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Sample records for high accuracy interferometric

  1. High-accuracy interferometric measurements of flatness and parallelism of a step gauge

    CSIR Research Space (South Africa)

    Kruger, OA

    2001-01-01

    Full Text Available The most commonly used method in the calibration of step gauges is the coordinate measuring machine (CMM), equipped with a laser interferometer for the highest accuracy. This paper describes a modification to a length-bar measuring machine...

  2. An airborne interferometric SAR system for high-performance 3D mapping

    Science.gov (United States)

    Lange, Martin; Gill, Paul

    2009-05-01

    With a vertical accuracy better than 1 m and collection rates up to 7000 km2/h, airborne interferometric synthetic aperture radars (InSAR) bridge the gap between space borne radar sensors and airborne optical LIDARs. This paper presents the latest generation of X-band InSAR sensors, developed by Intermap TechnologiesTM, which are operated on our four aircrafts. The sensors collect data for the NEXTMap(R) program - a digital elevation model (DEM) with 1 m vertical accuracy for the contiguous U.S., Hawaii, and most of Western Europe. For a successful operation, challenges like reduction of multipath reflections, very high interferometric phase stability, and a precise system calibration had to be mastered. Recent advances in sensor design, comprehensive system automation and diagnostics have increased the sensor reliability to a level where no radar operator is required onboard. Advanced flight planning significantly improved aircraft utilization and acquisition throughput, while reducing operational costs. Highly efficient data acquisition with straight flight lines up to 1200 km is daily routine meanwhile. The collected data pass though our automated processing cluster and finally are edited to our terrain model products. Extensive and rigorous quality control at every step of the workflow are key to maintain stable vertical accuracies of 1 m and horizontal accuracies of 2 m for our 3D maps. The combination of technical and operational advances presented in this paper enabled Intermap to survey two continents, producing 11 million km2 of uniform and accurate 3D terrain data.

  3. Interferometric determination of electron density in a high pressure hydrogen arc. 1. Calculation of refraction index

    Energy Technology Data Exchange (ETDEWEB)

    Radtke, R; Guenther, K; Ulbricht, R [Akademie der Wissenschaften der DDR, Berlin. Zentralinstitut fuer Elektronenphysik

    1980-01-14

    The refraction index of a hydrogen plasma in LTE was calculated as a function of the wavelength of observation, temperature and pressure, taking into account bound-bound and bound-free transitions of the neutral atom. According to the present calculation, the influence of excited states at higher temperatures is smaller than indicated by Baum et al (Plasma Phys.; 17: 79 (1975)) for argon. Using the calculations presented here, the interferometric investigation of a high pressure hydrogen arc should allow the determination of the electron density with an accuracy of the order of 1%.

  4. AN IMPROVED INTERFEROMETRIC CALIBRATION METHOD BASED ON INDEPENDENT PARAMETER DECOMPOSITION

    Directory of Open Access Journals (Sweden)

    J. Fan

    2018-04-01

    Full Text Available Interferometric SAR is sensitive to earth surface undulation. The accuracy of interferometric parameters plays a significant role in precise digital elevation model (DEM. The interferometric calibration is to obtain high-precision global DEM by calculating the interferometric parameters using ground control points (GCPs. However, interferometric parameters are always calculated jointly, making them difficult to decompose precisely. In this paper, we propose an interferometric calibration method based on independent parameter decomposition (IPD. Firstly, the parameters related to the interferometric SAR measurement are determined based on the three-dimensional reconstruction model. Secondly, the sensitivity of interferometric parameters is quantitatively analyzed after the geometric parameters are completely decomposed. Finally, each interferometric parameter is calculated based on IPD and interferometric calibration model is established. We take Weinan of Shanxi province as an example and choose 4 TerraDEM-X image pairs to carry out interferometric calibration experiment. The results show that the elevation accuracy of all SAR images is better than 2.54 m after interferometric calibration. Furthermore, the proposed method can obtain the accuracy of DEM products better than 2.43 m in the flat area and 6.97 m in the mountainous area, which can prove the correctness and effectiveness of the proposed IPD based interferometric calibration method. The results provide a technical basis for topographic mapping of 1 : 50000 and even larger scale in the flat area and mountainous area.

  5. An Improved Interferometric Calibration Method Based on Independent Parameter Decomposition

    Science.gov (United States)

    Fan, J.; Zuo, X.; Li, T.; Chen, Q.; Geng, X.

    2018-04-01

    Interferometric SAR is sensitive to earth surface undulation. The accuracy of interferometric parameters plays a significant role in precise digital elevation model (DEM). The interferometric calibration is to obtain high-precision global DEM by calculating the interferometric parameters using ground control points (GCPs). However, interferometric parameters are always calculated jointly, making them difficult to decompose precisely. In this paper, we propose an interferometric calibration method based on independent parameter decomposition (IPD). Firstly, the parameters related to the interferometric SAR measurement are determined based on the three-dimensional reconstruction model. Secondly, the sensitivity of interferometric parameters is quantitatively analyzed after the geometric parameters are completely decomposed. Finally, each interferometric parameter is calculated based on IPD and interferometric calibration model is established. We take Weinan of Shanxi province as an example and choose 4 TerraDEM-X image pairs to carry out interferometric calibration experiment. The results show that the elevation accuracy of all SAR images is better than 2.54 m after interferometric calibration. Furthermore, the proposed method can obtain the accuracy of DEM products better than 2.43 m in the flat area and 6.97 m in the mountainous area, which can prove the correctness and effectiveness of the proposed IPD based interferometric calibration method. The results provide a technical basis for topographic mapping of 1 : 50000 and even larger scale in the flat area and mountainous area.

  6. Laser interference lithography with highly accurate interferometric alignment

    NARCIS (Netherlands)

    van Soest, Frank J.; van Wolferen, Hendricus A.G.M.; Hoekstra, Hugo; de Ridder, R.M.; Worhoff, Kerstin; Lambeck, Paul

    It is shown experimentally that in laser interference lithography, by using a reference grating, respective grating layers can be positioned with high relative accuracy. A 0.001 degree angular and a few nanometers lateral resolution have been demonstrated.

  7. Robust snapshot interferometric spectropolarimetry.

    Science.gov (United States)

    Kim, Daesuk; Seo, Yoonho; Yoon, Yonghee; Dembele, Vamara; Yoon, Jae Woong; Lee, Kyu Jin; Magnusson, Robert

    2016-05-15

    This Letter describes a Stokes vector measurement method based on a snapshot interferometric common-path spectropolarimeter. The proposed scheme, which employs an interferometric polarization-modulation module, can extract the spectral polarimetric parameters Ψ(k) and Δ(k) of a transmissive anisotropic object by which an accurate Stokes vector can be calculated in the spectral domain. It is inherently strongly robust to the object 3D pose variation, since it is designed distinctly so that the measured object can be placed outside of the interferometric module. Experiments are conducted to verify the feasibility of the proposed system. The proposed snapshot scheme enables us to extract the spectral Stokes vector of a transmissive anisotropic object within tens of msec with high accuracy.

  8. A high-throughput surface plasmon resonance biosensor based on differential interferometric imaging

    International Nuclear Information System (INIS)

    Wang, Daqian; Ding, Lili; Zhang, Wei; Zhang, Enyao; Yu, Xinglong; Luo, Zhaofeng; Ou, Huichao

    2012-01-01

    A new high-throughput surface plasmon resonance (SPR) biosensor based on differential interferometric imaging is reported. The two SPR interferograms of the sensing surface are imaged on two CCD cameras. The phase difference between the two interferograms is 180°. The refractive index related factor (RIRF) of the sensing surface is calculated from the two simultaneously acquired interferograms. The simulation results indicate that the RIRF exhibits a linear relationship with the refractive index of the sensing surface and is unaffected by the noise, drift and intensity distribution of the light source. The affinity and kinetic information can be extracted in real time from continuously acquired RIRF distributions. The results of refractometry experiments show that the dynamic detection range of SPR differential interferometric imaging system can be over 0.015 refractive index unit (RIU). High refractive index resolution is down to 0.45 RU (1 RU = 1 × 10 −6 RIU). Imaging and protein microarray experiments demonstrate the ability of high-throughput detection. The aptamer experiments demonstrate that the SPR sensor based on differential interferometric imaging has a great capability to be implemented for high-throughput aptamer kinetic evaluation. These results suggest that this biosensor has the potential to be utilized in proteomics and drug discovery after further improvement. (paper)

  9. Squeezed light for the interferometric detection of high-frequency gravitational waves

    Science.gov (United States)

    Schnabel, R.; Harms, J.; Strain, K. A.; Danzmann, K.

    2004-03-01

    The quantum noise of the light field is a fundamental noise source in interferometric gravitational-wave detectors. Injected squeezed light is capable of reducing the quantum noise contribution to the detector noise floor to values that surpass the so-called standard quantum limit (SQL). In particular, squeezed light is useful for the detection of gravitational waves at high frequencies where interferometers are typically shot-noise limited, although the SQL might not be beaten in this case. We theoretically analyse the quantum noise of the signal-recycled laser interferometric gravitational-wave detector GEO 600 with additional input and output optics, namely frequency-dependent squeezing of the vacuum state of light entering the dark port and frequency-dependent homodyne detection. We focus on the frequency range between 1 kHz and 10 kHz, where, although signal recycled, the detector is still shot-noise limited. It is found that the GEO 600 detector with present design parameters will benefit from frequency-dependent squeezed light. Assuming a squeezing strength of -6 dB in quantum noise variance, the interferometer will become thermal noise limited up to 4 kHz without further reduction of bandwidth. At higher frequencies the linear noise spectral density of GEO 600 will still be dominated by shot noise and improved by a factor of 106dB/20dB ap 2 according to the squeezing strength assumed. The interferometer might reach a strain sensitivity of 6 × 10-23 above 1 kHz (tunable) with a bandwidth of around 350 Hz. We propose a scheme to implement the desired frequency-dependent squeezing by introducing an additional optical component into GEO 600's signal-recycling cavity.

  10. Squeezed light for the interferometric detection of high-frequency gravitational waves

    International Nuclear Information System (INIS)

    Schnabel, R; Harms, J; Strain, K A; Danzmann, K

    2004-01-01

    The quantum noise of the light field is a fundamental noise source in interferometric gravitational-wave detectors. Injected squeezed light is capable of reducing the quantum noise contribution to the detector noise floor to values that surpass the so-called standard quantum limit (SQL). In particular, squeezed light is useful for the detection of gravitational waves at high frequencies where interferometers are typically shot-noise limited, although the SQL might not be beaten in this case. We theoretically analyse the quantum noise of the signal-recycled laser interferometric gravitational-wave detector GEO 600 with additional input and output optics, namely frequency-dependent squeezing of the vacuum state of light entering the dark port and frequency-dependent homodyne detection. We focus on the frequency range between 1 kHz and 10 kHz, where, although signal recycled, the detector is still shot-noise limited. It is found that the GEO 600 detector with present design parameters will benefit from frequency-dependent squeezed light. Assuming a squeezing strength of -6 dB in quantum noise variance, the interferometer will become thermal noise limited up to 4 kHz without further reduction of bandwidth. At higher frequencies the linear noise spectral density of GEO 600 will still be dominated by shot noise and improved by a factor of 10 6dB/20dB ∼ 2 according to the squeezing strength assumed. The interferometer might reach a strain sensitivity of 6 x 10 -23 above 1 kHz (tunable) with a bandwidth of around 350 Hz. We propose a scheme to implement the desired frequency-dependent squeezing by introducing an additional optical component into GEO 600's signal-recycling cavity

  11. High current high accuracy IGBT pulse generator

    International Nuclear Information System (INIS)

    Nesterov, V.V.; Donaldson, A.R.

    1995-05-01

    A solid state pulse generator capable of delivering high current triangular or trapezoidal pulses into an inductive load has been developed at SLAC. Energy stored in a capacitor bank of the pulse generator is switched to the load through a pair of insulated gate bipolar transistors (IGBT). The circuit can then recover the remaining energy and transfer it back to the capacitor bank without reversing the capacitor voltage. A third IGBT device is employed to control the initial charge to the capacitor bank, a command charging technique, and to compensate for pulse to pulse power losses. The rack mounted pulse generator contains a 525 μF capacitor bank. It can deliver 500 A at 900V into inductive loads up to 3 mH. The current amplitude and discharge time are controlled to 0.02% accuracy by a precision controller through the SLAC central computer system. This pulse generator drives a series pair of extraction dipoles

  12. Surface slope metrology of highly curved x-ray optics with an interferometric microscope

    Science.gov (United States)

    Gevorkyan, Gevork S.; Centers, Gary; Polonska, Kateryna S.; Nikitin, Sergey M.; Lacey, Ian; Yashchuk, Valeriy V.

    2017-09-01

    The development of deterministic polishing techniques has given rise to vendors that manufacture high quality threedimensional x-ray optics. The surface metrology on these optics remains a difficult task. For the fabrication, vendors usually use unique surface metrology tools, generally developed on site, that are not available in the optical metrology labs at x-ray facilities. At the Advanced Light Source X-Ray Optics Laboratory, we have developed a rather straightforward interferometric-microscopy-based procedure capable of sub microradian characterization of sagittal slope variation of x-ray optics for two-dimensionally focusing and collimating (such as ellipsoids, paraboloids, etc.). In the paper, we provide the mathematical foundation of the procedure and describe the related instrument calibration. We also present analytical expression describing the ideal surface shape in the sagittal direction of a spheroid specified by the conjugate parameters of the optic's beamline application. The expression is useful when analyzing data obtained with such optics. The high efficiency of the developed measurement and data analysis procedures is demonstrated in results of measurements with a number of x-ray optics with sagittal radius of curvature between 56 mm and 480 mm. We also discuss potential areas of further improvement.

  13. Interferometric snapshot spectro-ellipsometry.

    Science.gov (United States)

    Dembele, Vamara; Jin, Moonseob; Choi, Inho; Chegal, Won; Kim, Daesuk

    2018-01-22

    We propose a snapshot spectroscopic ellipsometry and its applications for real-time thin-film thickness measurement. The proposed system employs an interferometric polarization-modulation module that can measure the spectroscopic ellipsometric phase for thin-film deposited on a substrate with a measurement speed of around 20 msec. It requires neither moving parts nor time dependent modulation devices. The accuracy of the proposed interferometric snapshot spectro-ellipsometer is analyzed through comparison with commercial equipment results.

  14. Fusion of space-borne multi-baseline and multi-frequency interferometric results based on extended Kalman filter to generate high quality DEMs

    Science.gov (United States)

    Zhang, Xiaojie; Zeng, Qiming; Jiao, Jian; Zhang, Jingfa

    2016-01-01

    Repeat-pass Interferometric Synthetic Aperture Radar (InSAR) is a technique that can be used to generate DEMs. But the accuracy of InSAR is greatly limited by geometrical distortions, atmospheric effect, and decorrelations, particularly in mountainous areas, such as western China where no high quality DEM has so far been accomplished. Since each of InSAR DEMs generated using data of different frequencies and baselines has their own advantages and disadvantages, it is therefore very potential to overcome some of the limitations of InSAR by fusing Multi-baseline and Multi-frequency Interferometric Results (MMIRs). This paper proposed a fusion method based on Extended Kalman Filter (EKF), which takes the InSAR-derived DEMs as states in prediction step and the flattened interferograms as observations in control step to generate the final fused DEM. Before the fusion, detection of layover and shadow regions, low-coherence regions and regions with large height error is carried out because MMIRs in these regions are believed to be unreliable and thereafter are excluded. The whole processing flow is tested with TerraSAR-X and Envisat ASAR datasets. Finally, the fused DEM is validated with ASTER GDEM and national standard DEM of China. The results demonstrate that the proposed method is effective even in low coherence areas.

  15. A study of cooling time reduction of interferometric cryogenic gravitational wave detectors using a high-emissivity coating

    Energy Technology Data Exchange (ETDEWEB)

    Sakakibara, Y.; Yamamoto, K.; Chen, D.; Tokoku, C.; Uchiyama, T.; Ohashi, M.; Kuroda, K. [Institute for Cosmic Ray Research (ICRR), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan); Kimura, N.; Suzuki, T.; Koike, S. [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2014-01-29

    In interferometric cryogenic gravitational wave detectors, there are plans to cool mirrors and their suspension systems (payloads) in order to reduce thermal noise, that is, one of the fundamental noise sources. Because of the large payload masses (several hundred kg in total) and their thermal isolation, a cooling time of several months is required. Our calculation shows that a high-emissivity coating (e.g. a diamond-like carbon (DLC) coating) can reduce the cooling time effectively by enhancing radiation heat transfer. Here, we have experimentally verified the effect of the DLC coating on the reduction of the cooling time.

  16. High Accuracy Transistor Compact Model Calibrations

    Energy Technology Data Exchange (ETDEWEB)

    Hembree, Charles E. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Mar, Alan [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Robertson, Perry J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    Typically, transistors are modeled by the application of calibrated nominal and range models. These models consists of differing parameter values that describe the location and the upper and lower limits of a distribution of some transistor characteristic such as current capacity. Correspond- ingly, when using this approach, high degrees of accuracy of the transistor models are not expected since the set of models is a surrogate for a statistical description of the devices. The use of these types of models describes expected performances considering the extremes of process or transistor deviations. In contrast, circuits that have very stringent accuracy requirements require modeling techniques with higher accuracy. Since these accurate models have low error in transistor descriptions, these models can be used to describe part to part variations as well as an accurate description of a single circuit instance. Thus, models that meet these stipulations also enable the calculation of quantifi- cation of margins with respect to a functional threshold and uncertainties in these margins. Given this need, new model high accuracy calibration techniques for bipolar junction transis- tors have been developed and are described in this report.

  17. High accuracy FIONA-AFM hybrid imaging

    International Nuclear Information System (INIS)

    Fronczek, D.N.; Quammen, C.; Wang, H.; Kisker, C.; Superfine, R.; Taylor, R.; Erie, D.A.; Tessmer, I.

    2011-01-01

    Multi-protein complexes are ubiquitous and play essential roles in many biological mechanisms. Single molecule imaging techniques such as electron microscopy (EM) and atomic force microscopy (AFM) are powerful methods for characterizing the structural properties of multi-protein and multi-protein-DNA complexes. However, a significant limitation to these techniques is the ability to distinguish different proteins from one another. Here, we combine high resolution fluorescence microscopy and AFM (FIONA-AFM) to allow the identification of different proteins in such complexes. Using quantum dots as fiducial markers in addition to fluorescently labeled proteins, we are able to align fluorescence and AFM information to ≥8 nm accuracy. This accuracy is sufficient to identify individual fluorescently labeled proteins in most multi-protein complexes. We investigate the limitations of localization precision and accuracy in fluorescence and AFM images separately and their effects on the overall registration accuracy of FIONA-AFM hybrid images. This combination of the two orthogonal techniques (FIONA and AFM) opens a wide spectrum of possible applications to the study of protein interactions, because AFM can yield high resolution (5-10 nm) information about the conformational properties of multi-protein complexes and the fluorescence can indicate spatial relationships of the proteins in the complexes. -- Research highlights: → Integration of fluorescent signals in AFM topography with high (<10 nm) accuracy. → Investigation of limitations and quantitative analysis of fluorescence-AFM image registration using quantum dots. → Fluorescence center tracking and display as localization probability distributions in AFM topography (FIONA-AFM). → Application of FIONA-AFM to a biological sample containing damaged DNA and the DNA repair proteins UvrA and UvrB conjugated to quantum dots.

  18. The nature of extragalactic radio-jets from high-resolution radio-interferometric observations

    OpenAIRE

    Perucho, Manel

    2014-01-01

    Extragalactic jets are a common feature of radio-loud active galaxies. The nature of the observed jets in relation to the bulk flow is still unclear. In particular it is not clear whether the observations of parsec-scale jets using the very long baseline interferometric technique (VLBI) reveal wave-like structures that develop and propagate along the jet, or trace the jet flow itself. In this contribution I review the evidence collected during the last years showing that the ridge-lines of he...

  19. High accuracy 3-D laser radar

    DEFF Research Database (Denmark)

    Busck, Jens; Heiselberg, Henning

    2004-01-01

    We have developed a mono-static staring 3-D laser radar based on gated viewing with range accuracy below 1 m at 10 m and 1 cm at 100. We use a high sensitivity, fast, intensified CCD camera, and a Nd:Yag passively Q-switched 32.4 kHz pulsed green laser at 532 nm. The CCD has 752x582 pixels. Camera...

  20. Modified interferometric imaging condition for reverse-time migration

    Science.gov (United States)

    Guo, Xue-Bao; Liu, Hong; Shi, Ying

    2018-01-01

    For reverse-time migration, high-resolution imaging mainly depends on the accuracy of the velocity model and the imaging condition. In practice, however, the small-scale components of the velocity model cannot be estimated by tomographical methods; therefore, the wavefields are not accurately reconstructed from the background velocity, and the imaging process will generate artefacts. Some of the noise is due to cross-correlation of unrelated seismic events. Interferometric imaging condition suppresses imaging noise very effectively, especially the unknown random disturbance of the small-scale part. The conventional interferometric imaging condition is extended in this study to obtain a new imaging condition based on the pseudo-Wigner distribution function (WDF). Numerical examples show that the modified interferometric imaging condition improves imaging precision.

  1. An ultra-high frequency boundary layer Doppler/interferometric profiler

    International Nuclear Information System (INIS)

    Van Baelen, J.S.

    1994-01-01

    The planetary boundary layer (PBL) is that portion of the earth's atmosphere that is directly influenced by the earth's surface. The PBL can be vigorously turbulent and range in depth from a few hundred meters to a few kilometers. Solar energy is primarily absorbed at the earth's surface and transmitted to the free atmosphere through boundary-layer processes. An accurate portrayal of these transfers within the PBL is crucial to understand and predict many atmospheric processes from pollutant dispersion to numerical weather prediction and numerical simulations of climate change. This paper describes and discusses wind profiling techniques, focusing on the newly developed radio acoustic sounding system (RASS), and reviews past efforts to measure flux within the PBL. A new UHF wind profiling radar, the UHF Doppler/Interferometric Boundary Layer Radar, for accurately measuring both mean and flux quantities, as well as wind divergence and acoustic wave propagation, is outlined

  2. A frequency domain radar interferometric imaging (FII) technique based on high-resolution methods

    Science.gov (United States)

    Luce, H.; Yamamoto, M.; Fukao, S.; Helal, D.; Crochet, M.

    2001-01-01

    In the present work, we propose a frequency-domain interferometric imaging (FII) technique for a better knowledge of the vertical distribution of the atmospheric scatterers detected by MST radars. This is an extension of the dual frequency-domain interferometry (FDI) technique to multiple frequencies. Its objective is to reduce the ambiguity (resulting from the use of only two adjacent frequencies), inherent with the FDI technique. Different methods, commonly used in antenna array processing, are first described within the context of application to the FII technique. These methods are the Fourier-based imaging, the Capon's and the singular value decomposition method used with the MUSIC algorithm. Some preliminary simulations and tests performed on data collected with the middle and upper atmosphere (MU) radar (Shigaraki, Japan) are also presented. This work is a first step in the developments of the FII technique which seems to be very promising.

  3. Spatially Extended and High-Velocity Dispersion Molecular Component in Spiral Galaxies: Single-Dish Versus Interferometric Observations

    Science.gov (United States)

    Caldú-Primo, Anahi; Schruba, Andreas; Walter, Fabian; Leroy, Adam; Bolatto, Alberto D.; Vogel, Stuart

    2015-02-01

    Recent studies of the molecular medium in nearby galaxies have provided mounting evidence that the molecular gas can exist in two phases: one that is clumpy and organized as molecular clouds and another one that is more diffuse. This last component has a higher velocity dispersion than the clumpy one. In order to investigate these two molecular components further, we compare the fluxes and line widths of CO in NGC 4736 and NGC 5055, two nearby spiral galaxies for which high-quality interferometric as well as single-dish data sets are available. Our analysis leads to two main results: (1) employing three different methods, we determine the flux recovery of the interferometer as compared to the single-dish to be within a range of 35%-74% for NGC 4736 and 81%-92% for NGC 5055, and (2) when focusing on high (S/N ≥ 5) lines of sight (LOSs), the single-dish line widths are larger by ˜(40 ± 20)% than the ones derived from interferometric data, which is in agreement with stacking all LOSs. These results point to a molecular gas component that is distributed over spatial scales larger than 30″(˜1 kpc), and is therefore filtered out by the interferometer. The available observations do not allow us to distinguish between a truly diffuse gas morphology and a uniform distribution of small clouds that are separated by less than the synthesized beam size (˜3″ or ˜100 pc), as they would both be invisible for the interferometer. This high velocity dispersion component has a dispersion similar to what is found in the atomic medium, as traced through observations of the H i line.

  4. Spatially extended and high-velocity dispersion molecular component in spiral galaxies: Single-dish versus interferometric observations

    International Nuclear Information System (INIS)

    Caldú-Primo, Anahi; Walter, Fabian; Schruba, Andreas; Leroy, Adam; Bolatto, Alberto D.; Vogel, Stuart

    2015-01-01

    Recent studies of the molecular medium in nearby galaxies have provided mounting evidence that the molecular gas can exist in two phases: one that is clumpy and organized as molecular clouds and another one that is more diffuse. This last component has a higher velocity dispersion than the clumpy one. In order to investigate these two molecular components further, we compare the fluxes and line widths of CO in NGC 4736 and NGC 5055, two nearby spiral galaxies for which high-quality interferometric as well as single-dish data sets are available. Our analysis leads to two main results: (1) employing three different methods, we determine the flux recovery of the interferometer as compared to the single-dish to be within a range of 35%–74% for NGC 4736 and 81%–92% for NGC 5055, and (2) when focusing on high (S/N ≥ 5) lines of sight (LOSs), the single-dish line widths are larger by ∼(40 ± 20)% than the ones derived from interferometric data, which is in agreement with stacking all LOSs. These results point to a molecular gas component that is distributed over spatial scales larger than 30″(∼1 kpc), and is therefore filtered out by the interferometer. The available observations do not allow us to distinguish between a truly diffuse gas morphology and a uniform distribution of small clouds that are separated by less than the synthesized beam size (∼3″ or ∼100 pc), as they would both be invisible for the interferometer. This high velocity dispersion component has a dispersion similar to what is found in the atomic medium, as traced through observations of the H i line.

  5. High accuracy satellite drag model (HASDM)

    Science.gov (United States)

    Storz, Mark F.; Bowman, Bruce R.; Branson, Major James I.; Casali, Stephen J.; Tobiska, W. Kent

    The dominant error source in force models used to predict low-perigee satellite trajectories is atmospheric drag. Errors in operational thermospheric density models cause significant errors in predicted satellite positions, since these models do not account for dynamic changes in atmospheric drag for orbit predictions. The Air Force Space Battlelab's High Accuracy Satellite Drag Model (HASDM) estimates and predicts (out three days) a dynamically varying global density field. HASDM includes the Dynamic Calibration Atmosphere (DCA) algorithm that solves for the phases and amplitudes of the diurnal and semidiurnal variations of thermospheric density near real-time from the observed drag effects on a set of Low Earth Orbit (LEO) calibration satellites. The density correction is expressed as a function of latitude, local solar time and altitude. In HASDM, a time series prediction filter relates the extreme ultraviolet (EUV) energy index E10.7 and the geomagnetic storm index ap, to the DCA density correction parameters. The E10.7 index is generated by the SOLAR2000 model, the first full spectrum model of solar irradiance. The estimated and predicted density fields will be used operationally to significantly improve the accuracy of predicted trajectories for all low-perigee satellites.

  6. Fast and High Accuracy Wire Scanner

    CERN Document Server

    Koujili, M; Koopman, J; Ramos, D; Sapinski, M; De Freitas, J; Ait Amira, Y; Djerdir, A

    2009-01-01

    Scanning of a high intensity particle beam imposes challenging requirements on a Wire Scanner system. It is expected to reach a scanning speed of 20 m.s-1 with a position accuracy of the order of 1 μm. In addition a timing accuracy better than 1 millisecond is needed. The adopted solution consists of a fork holding a wire rotating by a maximum of 200°. Fork, rotor and angular position sensor are mounted on the same axis and located in a chamber connected to the beam vacuum. The requirements imply the design of a system with extremely low vibration, vacuum compatibility, radiation and temperature tolerance. The adopted solution consists of a rotary brushless synchronous motor with the permanent magnet rotor installed inside of the vacuum chamber and the stator installed outside. The accurate position sensor will be mounted on the rotary shaft inside of the vacuum chamber, has to resist a bake-out temperature of 200°C and ionizing radiation up to a dozen of kGy/year. A digital feedback controller allows maxi...

  7. Self Calibrating Interferometric Sensor

    DEFF Research Database (Denmark)

    Sørensen, Henrik Schiøtt

    mask. The fabricated micro structures have been electroplated for later injection molding, showing the potential of the MIBD sensor to be mass produced with high reproducibility and sensitivity. In part three MIBD experiments on vital biological systems are described. Label–free binding studies of bio......This thesis deals with the development of an optical sensor based on micro interferometric backscatter detection (MIBD). A price effective, highly sensitive and ready for mass production platform is the goal of this project. The thesis covers three areas. The first part of the thesis deals...

  8. Electron ray tracing with high accuracy

    International Nuclear Information System (INIS)

    Saito, K.; Okubo, T.; Takamoto, K.; Uno, Y.; Kondo, M.

    1986-01-01

    An electron ray tracing program is developed to investigate the overall geometrical and chromatic aberrations in electron optical systems. The program also computes aberrations due to manufacturing errors in lenses and deflectors. Computation accuracy is improved by (1) calculating electrostatic and magnetic scalar potentials using the finite element method with third-order isoparametric elements, and (2) solving the modified ray equation which the aberrations satisfy. Computation accuracy of 4 nm is achieved for calculating optical properties of the system with an electrostatic lens

  9. Model Accuracy Comparison for High Resolution Insar Coherence Statistics Over Urban Areas

    Science.gov (United States)

    Zhang, Yue; Fu, Kun; Sun, Xian; Xu, Guangluan; Wang, Hongqi

    2016-06-01

    The interferometric coherence map derived from the cross-correlation of two complex registered synthetic aperture radar (SAR) images is the reflection of imaged targets. In many applications, it can act as an independent information source, or give additional information complementary to the intensity image. Specially, the statistical properties of the coherence are of great importance in land cover classification, segmentation and change detection. However, compared to the amount of work on the statistical characters of SAR intensity, there are quite fewer researches on interferometric SAR (InSAR) coherence statistics. And to our knowledge, all of the existing work that focuses on InSAR coherence statistics, models the coherence with Gaussian distribution with no discrimination on data resolutions or scene types. But the properties of coherence may be different for different data resolutions and scene types. In this paper, we investigate on the coherence statistics for high resolution data over urban areas, by making a comparison of the accuracy of several typical statistical models. Four typical land classes including buildings, trees, shadow and roads are selected as the representatives of urban areas. Firstly, several regions are selected from the coherence map manually and labelled with their corresponding classes respectively. Then we try to model the statistics of the pixel coherence for each type of region, with different models including Gaussian, Rayleigh, Weibull, Beta and Nakagami. Finally, we evaluate the model accuracy for each type of region. The experiments on TanDEM-X data show that the Beta model has a better performance than other distributions.

  10. MODEL ACCURACY COMPARISON FOR HIGH RESOLUTION INSAR COHERENCE STATISTICS OVER URBAN AREAS

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2016-06-01

    Full Text Available The interferometric coherence map derived from the cross-correlation of two complex registered synthetic aperture radar (SAR images is the reflection of imaged targets. In many applications, it can act as an independent information source, or give additional information complementary to the intensity image. Specially, the statistical properties of the coherence are of great importance in land cover classification, segmentation and change detection. However, compared to the amount of work on the statistical characters of SAR intensity, there are quite fewer researches on interferometric SAR (InSAR coherence statistics. And to our knowledge, all of the existing work that focuses on InSAR coherence statistics, models the coherence with Gaussian distribution with no discrimination on data resolutions or scene types. But the properties of coherence may be different for different data resolutions and scene types. In this paper, we investigate on the coherence statistics for high resolution data over urban areas, by making a comparison of the accuracy of several typical statistical models. Four typical land classes including buildings, trees, shadow and roads are selected as the representatives of urban areas. Firstly, several regions are selected from the coherence map manually and labelled with their corresponding classes respectively. Then we try to model the statistics of the pixel coherence for each type of region, with different models including Gaussian, Rayleigh, Weibull, Beta and Nakagami. Finally, we evaluate the model accuracy for each type of region. The experiments on TanDEM-X data show that the Beta model has a better performance than other distributions.

  11. The fresnel interferometric imager

    Science.gov (United States)

    Koechlin, Laurent; Serre, Denis; Deba, Paul; Pelló, Roser; Peillon, Christelle; Duchon, Paul; Gomez de Castro, Ana Ines; Karovska, Margarita; Désert, Jean-Michel; Ehrenreich, David; Hebrard, Guillaume; Lecavelier Des Etangs, Alain; Ferlet, Roger; Sing, David; Vidal-Madjar, Alfred

    2009-03-01

    The Fresnel Interferometric Imager has been proposed to the European Space Agency (ESA) Cosmic Vision plan as a class L mission. This mission addresses several themes of the CV Plan: Exoplanet study, Matter in extreme conditions, and The Universe taking shape. This paper is an abridged version of the original ESA proposal. We have removed most of the technical and financial issues, to concentrate on the instrumental design and astrophysical missions. The instrument proposed is an ultra-lightweight telescope, featuring a novel optical concept based on diffraction focussing. It yields high dynamic range images, while releasing constraints on positioning and manufacturing of the main optical elements. This concept should open the way to very large apertures in space. In this two spacecraft formation-flying instrument, one spacecraft holds the focussing element: the Fresnel interferometric array; the other spacecraft holds the field optics, focal instrumentation, and detectors. The Fresnel array proposed here is a 3.6 ×3.6 m square opaque foil punched with 105 to 106 void “subapertures”. Focusing is achieved with no other optical element: the shape and positioning of the subapertures (holes in the foil) is responsible for beam combining by diffraction, and 5% to 10% of the total incident light ends up into a sharp focus. The consequence of this high number of subapertures is high dynamic range images. In addition, as it uses only a combination of vacuum and opaque material, this focussing method is potentially efficient over a very broad wavelength domain. The focal length of such diffractive focussing devices is wavelength dependent. However, this can be corrected. We have tested optically the efficiency of the chromatism correction on artificial sources (500 < λ < 750 nm): the images are diffraction limited, and the dynamic range measured on an artificial double source reaches 6.2 10 - 6. We have also validated numerical simulation algorithms for larger Fresnel

  12. [Study of high energy nucleus-nucleus interactions with a Magnetic-Interferometric-Emulsion-Chamber

    International Nuclear Information System (INIS)

    Takahashi, Yoshiyuki.

    1990-01-01

    The Nuclear Physics group at the University of Alabama in Huntsville (UAH) has been analyzing 200 GeV/n S + Pb collision events with a Magnetic-Interactive-Emulsion-Chamber (MAGIC). The objectives of the research are to learn the nature of nuclear matter at high density of particles and to develop an all-particle tracking system for very high particle densities. To advance the study further, the detector capability has been improved so as to allow the best utilization of all-particle measurements. A design study for Pb + Pb interactions at 160 GeV/n was made for planned experiments in 1993

  13. Performance characterization of a pressure-tuned wide-angle Michelson interferometric spectral filter for high spectral resolution lidar

    Science.gov (United States)

    Seaman, Shane T.; Cook, Anthony L.; Scola, Salvatore J.; Hostetler, Chris A.; Miller, Ian; Welch, Wayne

    2015-09-01

    High Spectral Resolution Lidar (HSRL) is typically realized using an absorption filter to separate molecular returns from particulate returns. NASA Langley Research Center (LaRC) has designed and built a Pressure-Tuned Wide-Angle Michelson Interferometer (PTWAMI) as an alternate means to separate the two types of atmospheric returns. While absorption filters only work at certain wavelengths and suffer from low photon efficiency due to light absorption, an interferometric spectral filter can be designed for any wavelength and transmits nearly all incident photons. The interferometers developed at LaRC employ an air spacer in one arm, and a solid glass spacer in the other. Field widening is achieved by specific design and selection of the lengths and refractive indices of these two arms. The principal challenge in using such an interferometer as a spectral filter for HSRL aboard aircraft is that variations in glass temperature and air pressure cause changes in the interferometer's optical path difference. Therefore, a tuning mechanism is needed to actively accommodate for these changes. The pressure-tuning mechanism employed here relies on changing the pressure in an enclosed, air-filled arm of the interferometer to change the arm's optical path length. However, tuning using pressure will not adjust for tilt, mirror warpage, or thermally induced wavefront error, so the structural, thermal, and optical behavior of the device must be well understood and optimized in the design and manufacturing process. The PTWAMI has been characterized for particulate transmission ratio, wavefront error, and tilt, and shows acceptable performance for use in an HSRL instrument.

  14. Direct interferometric measurement of the atomic dipole phase in high-order harmonic generation

    International Nuclear Information System (INIS)

    Chiara Corsi; Angela Pirri; Emiliano Sali

    2006-01-01

    Complete test of publication follows. For low gas densities and negligible ionization, the so-called atomic dipole phase, connected with the electronic dynamics involved in the generation process, is the main source of phase modulation and incoherence of high-order harmonics. To accurately determine these laser-intensity-induced phase shifts is therefore of great importance, both for the possible spectroscopic applications of harmonics and for the controlled generation of attosecond pulses. In a semiclassical description, only two electronic trajectories contribute to generate plateau harmonics during each pump optical half-cycle. Electrons appearing in the continuum by tunnel ionization may follow two different quantum paths, namely a long (l) and a short (s) trajectory before recombination. According to the SFA approximation, the harmonic of q th order acquires a phase proportional to the electronic classical action, and simply given by: ψ 0 j (r,t) -α q j I(r,t) with j = l, s where α q j are non-linear phase coefficients, roughly proportional to the time that the originating electron spends in the continuum before recombination. The space and time variation of the laser intensity (I(r,t), causes just a little phase modulation for the s-trajectory harmonic component, while the l-trajectory component becomes strongly chirped and spatially defocused; this gives rise to two spatially-separated regions having different temporal coherence. Here we report the first direct measurement of such atomic dipole phase in the process of high-order harmonic generation. Differently from previous measurements based in the most natural way, i.e., by interferometry. Two phase-locked pump pulses generate two phase-locked harmonic pulses in two nearby positions in a gas jet; one of them is used as a fixed phase reference while the generating intensity of the other is varied. The shift of the XUV interference fringes observed in the far field then gives a direct estimate of the

  15. Development and Evaluation of the Interferometric Monitor for Greenhouse Gases: a High-throughput Fourier-transform Infrared Radiometer for Nadir Earth Observation

    Science.gov (United States)

    Kobayashi, Hirokazu; Shimota, Akiro; Kondo, Kayoko; Okumura, Eisuke; Kameda, Yoshihiko; Shimoda, Haruhisa; Ogawa, Toshihiro

    1999-11-01

    The interferometric monitor for greenhouse gases (IMG) was the precursor of the high-resolution Fourier-transform infrared radiometer (FTIR) onboard a satellite for observation of the Earth. The IMG endured the stress of a rocket launch, demonstrating that the high-resolution, high-throughput spectrometer is indeed feasible for use onboard a satellite. The IMG adopted a newly developed lubricant-free magnetic suspension mechanism and a dynamic alignment system for the moving mirror with a maximum traveling distance of 10 cm. We present the instrumentation of the IMG, characteristics of the movable mirror drive system, and the evaluation results of sensor specifications during space operation.

  16. Automated data reduction for optical interferometric data

    International Nuclear Information System (INIS)

    Boyd, R.D.; Miller, D.J.; Ghiglia, D.C.

    1983-01-01

    The potential for significant progress in understanding many transport processes exists through the use of a rapid and automated data reduction process of optical interferometric data. An example involving natural convection in a horizontal annulus is used to demonstrate that the accuracy possible in automated techniques is better than 99.0%

  17. A portfolio of products from the rapid terrain visualization interferometric SAR

    Science.gov (United States)

    Bickel, Douglas L.; Doerry, Armin W.

    2007-04-01

    The Rapid Terrain Visualization interferometric synthetic aperture radar was designed and built at Sandia National Laboratories as part of an Advanced Concept Technology Demonstration (ACTD) to "demonstrate the technologies and infrastructure to meet the Army requirement for rapid generation of digital topographic data to support emerging crisis or contingencies." This sensor was built by Sandia National Laboratories for the Joint Programs Sustainment and Development (JPSD) Project Office to provide highly accurate digital elevation models (DEMs) for military and civilian customers, both inside and outside of the United States. The sensor achieved better than HRTe Level IV position accuracy in near real-time. The system was flown on a deHavilland DHC-7 Army aircraft. This paper presents a collection of images and data products from the Rapid Terrain Visualization interferometric synthetic aperture radar. The imagery includes orthorectified images and DEMs from the RTV interferometric SAR radar.

  18. High-Accuracy Tidal Flat Digital Elevation Model Construction Using TanDEM-X Science Phase Data

    Science.gov (United States)

    Lee, Seung-Kuk; Ryu, Joo-Hyung

    2017-01-01

    This study explored the feasibility of using TanDEM-X (TDX) interferometric observations of tidal flats for digital elevation model (DEM) construction. Our goal was to generate high-precision DEMs in tidal flat areas, because accurate intertidal zone data are essential for monitoring coastal environment sand erosion processes. To monitor dynamic coastal changes caused by waves, currents, and tides, very accurate DEMs with high spatial resolution are required. The bi- and monostatic modes of the TDX interferometer employed during the TDX science phase provided a great opportunity for highly accurate intertidal DEM construction using radar interferometry with no time lag (bistatic mode) or an approximately 10-s temporal baseline (monostatic mode) between the master and slave synthetic aperture radar image acquisitions. In this study, DEM construction in tidal flat areas was first optimized based on the TDX system parameters used in various TDX modes. We successfully generated intertidal zone DEMs with 57-m spatial resolutions and interferometric height accuracies better than 0.15 m for three representative tidal flats on the west coast of the Korean Peninsula. Finally, we validated these TDX DEMs against real-time kinematic-GPS measurements acquired in two tidal flat areas; the correlation coefficient was 0.97 with a root mean square error of 0.20 m.

  19. High accuracy in silico sulfotransferase models.

    Science.gov (United States)

    Cook, Ian; Wang, Ting; Falany, Charles N; Leyh, Thomas S

    2013-11-29

    Predicting enzymatic behavior in silico is an integral part of our efforts to understand biology. Hundreds of millions of compounds lie in targeted in silico libraries waiting for their metabolic potential to be discovered. In silico "enzymes" capable of accurately determining whether compounds can inhibit or react is often the missing piece in this endeavor. This problem has now been solved for the cytosolic sulfotransferases (SULTs). SULTs regulate the bioactivities of thousands of compounds--endogenous metabolites, drugs and other xenobiotics--by transferring the sulfuryl moiety (SO3) from 3'-phosphoadenosine 5'-phosphosulfate to the hydroxyls and primary amines of these acceptors. SULT1A1 and 2A1 catalyze the majority of sulfation that occurs during human Phase II metabolism. Here, recent insights into the structure and dynamics of SULT binding and reactivity are incorporated into in silico models of 1A1 and 2A1 that are used to identify substrates and inhibitors in a structurally diverse set of 1,455 high value compounds: the FDA-approved small molecule drugs. The SULT1A1 models predict 76 substrates. Of these, 53 were known substrates. Of the remaining 23, 21 were tested, and all were sulfated. The SULT2A1 models predict 22 substrates, 14 of which are known substrates. Of the remaining 8, 4 were tested, and all are substrates. The models proved to be 100% accurate in identifying substrates and made no false predictions at Kd thresholds of 100 μM. In total, 23 "new" drug substrates were identified, and new linkages to drug inhibitors are predicted. It now appears to be possible to accurately predict Phase II sulfonation in silico.

  20. High accuracy autonomous navigation using the global positioning system (GPS)

    Science.gov (United States)

    Truong, Son H.; Hart, Roger C.; Shoan, Wendy C.; Wood, Terri; Long, Anne C.; Oza, Dipak H.; Lee, Taesul

    1997-01-01

    The application of global positioning system (GPS) technology to the improvement of the accuracy and economy of spacecraft navigation, is reported. High-accuracy autonomous navigation algorithms are currently being qualified in conjunction with the GPS attitude determination flyer (GADFLY) experiment for the small satellite technology initiative Lewis spacecraft. Preflight performance assessments indicated that these algorithms are able to provide a real time total position accuracy of better than 10 m and a velocity accuracy of better than 0.01 m/s, with selective availability at typical levels. It is expected that the position accuracy will be increased to 2 m if corrections are provided by the GPS wide area augmentation system.

  1. Systematic Calibration for Ultra-High Accuracy Inertial Measurement Units

    Directory of Open Access Journals (Sweden)

    Qingzhong Cai

    2016-06-01

    Full Text Available An inertial navigation system (INS has been widely used in challenging GPS environments. With the rapid development of modern physics, an atomic gyroscope will come into use in the near future with a predicted accuracy of 5 × 10−6°/h or better. However, existing calibration methods and devices can not satisfy the accuracy requirements of future ultra-high accuracy inertial sensors. In this paper, an improved calibration model is established by introducing gyro g-sensitivity errors, accelerometer cross-coupling errors and lever arm errors. A systematic calibration method is proposed based on a 51-state Kalman filter and smoother. Simulation results show that the proposed calibration method can realize the estimation of all the parameters using a common dual-axis turntable. Laboratory and sailing tests prove that the position accuracy in a five-day inertial navigation can be improved about 8% by the proposed calibration method. The accuracy can be improved at least 20% when the position accuracy of the atomic gyro INS can reach a level of 0.1 nautical miles/5 d. Compared with the existing calibration methods, the proposed method, with more error sources and high order small error parameters calibrated for ultra-high accuracy inertial measurement units (IMUs using common turntables, has a great application potential in future atomic gyro INSs.

  2. MUSCLE: multiple sequence alignment with high accuracy and high throughput.

    Science.gov (United States)

    Edgar, Robert C

    2004-01-01

    We describe MUSCLE, a new computer program for creating multiple alignments of protein sequences. Elements of the algorithm include fast distance estimation using kmer counting, progressive alignment using a new profile function we call the log-expectation score, and refinement using tree-dependent restricted partitioning. The speed and accuracy of MUSCLE are compared with T-Coffee, MAFFT and CLUSTALW on four test sets of reference alignments: BAliBASE, SABmark, SMART and a new benchmark, PREFAB. MUSCLE achieves the highest, or joint highest, rank in accuracy on each of these sets. Without refinement, MUSCLE achieves average accuracy statistically indistinguishable from T-Coffee and MAFFT, and is the fastest of the tested methods for large numbers of sequences, aligning 5000 sequences of average length 350 in 7 min on a current desktop computer. The MUSCLE program, source code and PREFAB test data are freely available at http://www.drive5. com/muscle.

  3. High accuracy wavelength calibration for a scanning visible spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Scotti, Filippo; Bell, Ronald E. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2010-10-15

    Spectroscopic applications for plasma velocity measurements often require wavelength accuracies {<=}0.2 A. An automated calibration, which is stable over time and environmental conditions without the need to recalibrate after each grating movement, was developed for a scanning spectrometer to achieve high wavelength accuracy over the visible spectrum. This method fits all relevant spectrometer parameters using multiple calibration spectra. With a stepping-motor controlled sine drive, an accuracy of {approx}0.25 A has been demonstrated. With the addition of a high resolution (0.075 arc sec) optical encoder on the grating stage, greater precision ({approx}0.005 A) is possible, allowing absolute velocity measurements within {approx}0.3 km/s. This level of precision requires monitoring of atmospheric temperature and pressure and of grating bulk temperature to correct for changes in the refractive index of air and the groove density, respectively.

  4. The rapid terrain visualization interferometric synthetic aperture radar sensor

    Science.gov (United States)

    Graham, Robert H.; Bickel, Douglas L.; Hensley, William H.

    2003-11-01

    The Rapid Terrain Visualization interferometric synthetic aperture radar was designed and built at Sandia National Laboratories as part of an Advanced Concept Technology Demonstration (ACTD) to "demonstrate the technologies and infrastructure to meet the Army requirement for rapid generation of digital topographic data to support emerging crisis or contingencies." This sensor is currently being operated by Sandia National Laboratories for the Joint Precision Strike Demonstration (JPSD) Project Office to provide highly accurate digital elevation models (DEMs) for military and civilian customers, both inside and outside of the United States. The sensor achieves better than DTED Level IV position accuracy in near real-time. The system is being flown on a deHavilland DHC-7 Army aircraft. This paper outlines some of the technologies used in the design of the system, discusses the performance, and will discuss operational issues. In addition, we will show results from recent flight tests, including high accuracy maps taken of the San Diego area.

  5. Interferometric filters for spectral discrimination in high-spectral-resolution lidar: performance comparisons between Fabry-Perot interferometer and field-widened Michelson interferometer.

    Science.gov (United States)

    Cheng, Zhongtao; Liu, Dong; Yang, Yongying; Yang, Liming; Huang, Hanlu

    2013-11-10

    Thanks to wavelength flexibility, interferometric filters such as Fabry-Perot interferometers (FPIs) and field-widened Michelson interferometers (FWMIs) have shown great convenience for spectrally separating the molecule and aerosol scattering components in the high-spectral-resolution lidar (HSRL) return signal. In this paper, performance comparisons between the FPI and FWMI as a spectroscopic discrimination filter in HSRL are performed. We first present a theoretical method for spectral transmission analysis and quantitative evaluation on the spectral discrimination. Then the process in determining the parameters of the FPI and FWMI for the performance comparisons is described. The influences from the incident field of view (FOV), the cumulative wavefront error induced by practical imperfections, and the frequency locking error on the spectral discrimination performance of the two filters are discussed in detail. Quantitative analyses demonstrate that FPI can produce higher transmittance while the remarkable spectral discrimination is one of the most appealing advantages of FWMI. As a result of the field-widened design, the FWMI still performs well even under the illumination with large FOV while the FPI is only qualified for a small incident angle. The cumulative wavefront error attaches a great effect on the spectral discrimination performance of the interferometric filters. We suggest if a cumulative wavefront error is less than 0.05 waves RMS, it is beneficial to employ the FWMI; otherwise, FPI may be more proper. Although the FWMI shows much more sensitivity to the frequency locking error, it can outperform the FPI given a locking error less than 0.1 GHz is achieved. In summary, the FWMI is very competent in HSRL applications if these practical engineering and control problems can be solved, theoretically. Some other estimations neglected in this paper can also be carried out through the analytical method illustrated herein.

  6. The use of low density high accuracy (LDHA) data for correction of high density low accuracy (HDLA) point cloud

    Science.gov (United States)

    Rak, Michal Bartosz; Wozniak, Adam; Mayer, J. R. R.

    2016-06-01

    Coordinate measuring techniques rely on computer processing of coordinate values of points gathered from physical surfaces using contact or non-contact methods. Contact measurements are characterized by low density and high accuracy. On the other hand optical methods gather high density data of the whole object in a short time but with accuracy at least one order of magnitude lower than for contact measurements. Thus the drawback of contact methods is low density of data, while for non-contact methods it is low accuracy. In this paper a method for fusion of data from two measurements of fundamentally different nature: high density low accuracy (HDLA) and low density high accuracy (LDHA) is presented to overcome the limitations of both measuring methods. In the proposed method the concept of virtual markers is used to find a representation of pairs of corresponding characteristic points in both sets of data. In each pair the coordinates of the point from contact measurements is treated as a reference for the corresponding point from non-contact measurement. Transformation enabling displacement of characteristic points from optical measurement to their match from contact measurements is determined and applied to the whole point cloud. The efficiency of the proposed algorithm was evaluated by comparison with data from a coordinate measuring machine (CMM). Three surfaces were used for this evaluation: plane, turbine blade and engine cover. For the planar surface the achieved improvement was of around 200 μm. Similar results were obtained for the turbine blade but for the engine cover the improvement was smaller. For both freeform surfaces the improvement was higher for raw data than for data after creation of mesh of triangles.

  7. High-accuracy measurements of the normal specular reflectance

    International Nuclear Information System (INIS)

    Voarino, Philippe; Piombini, Herve; Sabary, Frederic; Marteau, Daniel; Dubard, Jimmy; Hameury, Jacques; Filtz, Jean Remy

    2008-01-01

    The French Laser Megajoule (LMJ) is designed and constructed by the French Commissariata l'Energie Atomique (CEA). Its amplifying section needs highly reflective multilayer mirrors for the flash lamps. To monitor and improve the coating process, the reflectors have to be characterized to high accuracy. The described spectrophotometer is designed to measure normal specular reflectance with high repeatability by using a small spot size of 100 μm. Results are compared with ellipsometric measurements. The instrument can also perform spatial characterization to detect coating nonuniformity

  8. High accuracy 3D electromagnetic finite element analysis

    International Nuclear Information System (INIS)

    Nelson, E.M.

    1996-01-01

    A high accuracy 3D electromagnetic finite element field solver employing quadratic hexahedral elements and quadratic mixed-order one-form basis functions will be described. The solver is based on an object-oriented C++ class library. Test cases demonstrate that frequency errors less than 10 ppm can be achieved using modest workstations, and that the solutions have no contamination from spurious modes. The role of differential geometry and geometrical physics in finite element analysis will also be discussed

  9. High accuracy 3D electromagnetic finite element analysis

    International Nuclear Information System (INIS)

    Nelson, Eric M.

    1997-01-01

    A high accuracy 3D electromagnetic finite element field solver employing quadratic hexahedral elements and quadratic mixed-order one-form basis functions will be described. The solver is based on an object-oriented C++ class library. Test cases demonstrate that frequency errors less than 10 ppm can be achieved using modest workstations, and that the solutions have no contamination from spurious modes. The role of differential geometry and geometrical physics in finite element analysis will also be discussed

  10. Why is a high accuracy needed in dosimetry

    International Nuclear Information System (INIS)

    Lanzl, L.H.

    1976-01-01

    Dose and exposure intercomparisons on a national or international basis have become an important component of quality assurance in the practice of good radiotherapy. A high degree of accuracy of γ and x radiation dosimetry is essential in our international society, where medical information is so readily exchanged and used. The value of accurate dosimetry lies mainly in the avoidance of complications in normal tissue and an optimal degree of tumor control

  11. Achieving High Accuracy in Calculations of NMR Parameters

    DEFF Research Database (Denmark)

    Faber, Rasmus

    quantum chemical methods have been developed, the calculation of NMR parameters with quantitative accuracy is far from trivial. In this thesis I address some of the issues that makes accurate calculation of NMR parameters so challenging, with the main focus on SSCCs. High accuracy quantum chemical......, but no programs were available to perform such calculations. As part of this thesis the CFOUR program has therefore been extended to allow the calculation of SSCCs using the CC3 method. CC3 calculations of SSCCs have then been performed for several molecules, including some difficult cases. These results show...... vibrations must be included. The calculation of vibrational corrections to NMR parameters has been reviewed as part of this thesis. A study of the basis set convergence of vibrational corrections to nuclear shielding constants has also been performed. The basis set error in vibrational correction...

  12. A high accuracy land use/cover retrieval system

    Directory of Open Access Journals (Sweden)

    Alaa Hefnawy

    2012-03-01

    Full Text Available The effects of spatial resolution on the accuracy of mapping land use/cover types have received increasing attention as a large number of multi-scale earth observation data become available. Although many methods of semi automated image classification of remotely sensed data have been established for improving the accuracy of land use/cover classification during the past 40 years, most of them were employed in single-resolution image classification, which led to unsatisfactory results. In this paper, we propose a multi-resolution fast adaptive content-based retrieval system of satellite images. Through our proposed system, we apply a Super Resolution technique for the Landsat-TM images to have a high resolution dataset. The human–computer interactive system is based on modified radial basis function for retrieval of satellite database images. We apply the backpropagation supervised artificial neural network classifier for both the multi and single resolution datasets. The results show significant improved land use/cover classification accuracy for the multi-resolution approach compared with those from single-resolution approach.

  13. Two high accuracy digital integrators for Rogowski current transducers

    Science.gov (United States)

    Luo, Pan-dian; Li, Hong-bin; Li, Zhen-hua

    2014-01-01

    The Rogowski current transducers have been widely used in AC current measurement, but their accuracy is mainly subject to the analog integrators, which have typical problems such as poor long-term stability and being susceptible to environmental conditions. The digital integrators can be another choice, but they cannot obtain a stable and accurate output for the reason that the DC component in original signal can be accumulated, which will lead to output DC drift. Unknown initial conditions can also result in integral output DC offset. This paper proposes two improved digital integrators used in Rogowski current transducers instead of traditional analog integrators for high measuring accuracy. A proportional-integral-derivative (PID) feedback controller and an attenuation coefficient have been applied in improving the Al-Alaoui integrator to change its DC response and get an ideal frequency response. For the special design in the field of digital signal processing, the improved digital integrators have better performance than analog integrators. Simulation models are built for the purpose of verification and comparison. The experiments prove that the designed integrators can achieve higher accuracy than analog integrators in steady-state response, transient-state response, and temperature changing condition.

  14. High Accuracy Piezoelectric Kinemometer; Cinemometro piezoelectrico de alta exactitud (VUAE)

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez Martinez, F. J.; Frutos, J. de; Pastor, C.; Vazquez Rodriguez, M.

    2012-07-01

    We have developed a portable computerized and low consumption, our system is called High Accuracy Piezoelectric Kinemometer measurement, herein VUAE. By the high accuracy obtained by VUAE it make able to use the VUAE to obtain references measurements of system for measuring Speeds in Vehicles. Therefore VUAE could be used how reference equipment to estimate the error of installed kinemometers. The VUAE was created with n (n=2) pairs of ultrasonic transmitter-receiver, herein E-Rult. The transmitters used in the n couples E-Rult generate n ultrasonic barriers and receivers receive the echoes when the vehicle crosses the barriers. Digital processing of the echoes signals let us to obtain acceptable signals. Later, by mean of cross correlation technics is possible make a highly exact estimation of speed of the vehicle. The log of the moments of interception and the distance between each of the n ultrasounds allows for a highly exact estimation of speed of the vehicle. VUAE speed measurements were compared to a speed reference system based on piezoelectric cables. (Author) 11 refs.

  15. High accuracy 3D electromagnetic finite element analysis

    International Nuclear Information System (INIS)

    Nelson, E.M.

    1997-01-01

    A high accuracy 3D electromagnetic finite element field solver employing quadratic hexahedral elements and quadratic mixed-order one-form basis functions will be described. The solver is based on an object-oriented C++ class library. Test cases demonstrate that frequency errors less than 10 ppm can be achieved using modest workstations, and that the solutions have no contamination from spurious modes. The role of differential geometry and geometrical physics in finite element analysis will also be discussed. copyright 1997 American Institute of Physics

  16. Mission Analysis and Orbit Control of Interferometric Wheel Formation Flying

    Science.gov (United States)

    Fourcade, J.

    Flying satellite in formation requires maintaining the specific relative geometry of the spacecraft with high precision. This requirement raises new problem of orbit control. This paper presents the results of the mission analysis of a low Earth observation system, the interferometric wheel, patented by CNES. This wheel is made up of three receiving spacecraft, which follow an emitting Earth observation radar satellite. The first part of this paper presents trades off which were performed to choose orbital elements of the formation flying which fulfils all constraints. The second part presents orbit positioning strategies including reconfiguration of the wheel to change its size. The last part describes the station keeping of the formation. Two kinds of constraints are imposed by the interferometric system : a constraint on the distance between the wheel and the radar satellite, and constraints on the distance between the wheel satellites. The first constraint is fulfilled with a classical chemical station keeping strategy. The second one is fulfilled using pure passive actuators. Due to the high stability of the relative eccentricity of the formation, only the relative semi major axis had to be controlled. Differential drag due to differential attitude motion was used to control relative altitude. An autonomous orbit controller was developed and tested. The final accuracy is a relative station keeping better than few meters for a wheel size of one kilometer.

  17. High-accuracy mass spectrometry for fundamental studies.

    Science.gov (United States)

    Kluge, H-Jürgen

    2010-01-01

    Mass spectrometry for fundamental studies in metrology and atomic, nuclear and particle physics requires extreme sensitivity and efficiency as well as ultimate resolving power and accuracy. An overview will be given on the global status of high-accuracy mass spectrometry for fundamental physics and metrology. Three quite different examples of modern mass spectrometric experiments in physics are presented: (i) the retardation spectrometer KATRIN at the Forschungszentrum Karlsruhe, employing electrostatic filtering in combination with magnetic-adiabatic collimation-the biggest mass spectrometer for determining the smallest mass, i.e. the mass of the electron anti-neutrino, (ii) the Experimental Cooler-Storage Ring at GSI-a mass spectrometer of medium size, relative to other accelerators, for determining medium-heavy masses and (iii) the Penning trap facility, SHIPTRAP, at GSI-the smallest mass spectrometer for determining the heaviest masses, those of super-heavy elements. Finally, a short view into the future will address the GSI project HITRAP at GSI for fundamental studies with highly-charged ions.

  18. Read-only high accuracy volume holographic optical correlator

    Science.gov (United States)

    Zhao, Tian; Li, Jingming; Cao, Liangcai; He, Qingsheng; Jin, Guofan

    2011-10-01

    A read-only volume holographic correlator (VHC) is proposed. After the recording of all of the correlation database pages by angular multiplexing, a stand-alone read-only high accuracy VHC will be separated from the VHC recording facilities which include the high-power laser and the angular multiplexing system. The stand-alone VHC has its own low power readout laser and very compact and simple structure. Since there are two lasers that are employed for recording and readout, respectively, the optical alignment tolerance of the laser illumination on the SLM is very sensitive. The twodimensional angular tolerance is analyzed based on the theoretical model of the volume holographic correlator. The experimental demonstration of the proposed read-only VHC is introduced and discussed.

  19. Atom interferometric gravity gradiometer: Disturbance compensation and mobile gradiometry

    Science.gov (United States)

    Mahadeswaraswamy, Chetan

    First ever mobile gravity gradient measurement based on Atom Interferometric sensors has been demonstrated. Mobile gravity gradiometers play a significant role in high accuracy inertial navigation systems in order to distinguish inertial acceleration and acceleration due to gravity. The gravity gradiometer consists of two atom interferometric accelerometers. In each of the accelerometer an ensemble of laser cooled Cesium atoms is dropped and using counter propagating Raman pulses (pi/2-pi-pi/2) the ensemble is split into two states for carrying out atom interferometry. The interferometer phase is proportional to the specific force experienced by the atoms which is a combination of inertial acceleration and acceleration due to gravity. The difference in phase between the two atom interferometric sensors is proportional to gravity gradient if the platform does not undergo any rotational motion. However, any rotational motion of the platform induces spurious gravity gradient measurements. This apparent gravity gradient due to platform rotation is considerably different for an atom interferometric sensor compared to a conventional force rebalance type sensor. The atoms are in free fall and are not influenced by the motion of the case except at the instants of Raman pulses. A model for determining apparent gravity gradient due to rotation of platform was developed and experimentally verified for different frequencies. This transfer function measurement also lead to the development of a new technique for aligning the Raman laser beams with the atom clusters to within 20 mu rad. This gravity gradiometer is situated in a truck for the purpose of undertaking mobile surveys. A disturbance compensation system was designed and built in order to compensate for the rotational disturbances experienced on the floor of a truck. An electric drive system was also designed specifically to be able to move the truck in a uniform motion at very low speeds of about 1cm/s. A 250 x10-9 s-2

  20. Synchrotron accelerator technology for proton beam therapy with high accuracy

    International Nuclear Information System (INIS)

    Hiramoto, Kazuo

    2009-01-01

    Proton beam therapy was applied at the beginning to head and neck cancers, but it is now extended to prostate, lung and liver cancers. Thus the need for a pencil beam scanning method is increasing. With this method radiation dose concentration property of the proton beam will be further intensified. Hitachi group has supplied a pencil beam scanning therapy system as the first one for M. D. Anderson Hospital in United States, and it has been operational since May 2008. Hitachi group has been developing proton therapy system to correspond high-accuracy proton therapy to concentrate the dose in the diseased part which is located with various depths, and which sometimes has complicated shape. The author described here on the synchrotron accelerator technology that is an important element for constituting the proton therapy system. (K.Y.)

  1. High accuracy mantle convection simulation through modern numerical methods

    KAUST Repository

    Kronbichler, Martin

    2012-08-21

    Numerical simulation of the processes in the Earth\\'s mantle is a key piece in understanding its dynamics, composition, history and interaction with the lithosphere and the Earth\\'s core. However, doing so presents many practical difficulties related to the numerical methods that can accurately represent these processes at relevant scales. This paper presents an overview of the state of the art in algorithms for high-Rayleigh number flows such as those in the Earth\\'s mantle, and discusses their implementation in the Open Source code Aspect (Advanced Solver for Problems in Earth\\'s ConvecTion). Specifically, we show how an interconnected set of methods for adaptive mesh refinement (AMR), higher order spatial and temporal discretizations, advection stabilization and efficient linear solvers can provide high accuracy at a numerical cost unachievable with traditional methods, and how these methods can be designed in a way so that they scale to large numbers of processors on compute clusters. Aspect relies on the numerical software packages deal.II and Trilinos, enabling us to focus on high level code and keeping our implementation compact. We present results from validation tests using widely used benchmarks for our code, as well as scaling results from parallel runs. © 2012 The Authors Geophysical Journal International © 2012 RAS.

  2. High accuracy magnetic field mapping of the LEP spectrometer magnet

    CERN Document Server

    Roncarolo, F

    2000-01-01

    The Large Electron Positron accelerator (LEP) is a storage ring which has been operated since 1989 at the European Laboratory for Particle Physics (CERN), located in the Geneva area. It is intended to experimentally verify the Standard Model theory and in particular to detect with high accuracy the mass of the electro-weak force bosons. Electrons and positrons are accelerated inside the LEP ring in opposite directions and forced to collide at four locations, once they reach an energy high enough for the experimental purposes. During head-to-head collisions the leptons loose all their energy and a huge amount of energy is concentrated in a small region. In this condition the energy is quickly converted in other particles which tend to go away from the interaction point. The higher the energy of the leptons before the collisions, the higher the mass of the particles that can escape. At LEP four large experimental detectors are accommodated. All detectors are multi purpose detectors covering a solid angle of alm...

  3. Fusion of Multi-Temporal Interferometric Coherence and Optical Image Data for the 2016 Kumamoto Earthquake Damage Assessment

    Directory of Open Access Journals (Sweden)

    Nopphawan Tamkuan

    2017-06-01

    Full Text Available Earthquakes are one of the most devastating types of natural disasters, and happen with little to no warning. This study combined Landsat-8 and interferometric ALOS-2 coherence data without training area techniques by classifying the remote sensing ratios of specific features for damage assessment. Waterbodies and highly vegetated areas were extracted by the modified normalized difference water index (MNDWI and normalized difference vegetation index (NDVI, respectively, from after-earthquake images in order to improve the accuracy of damage maps. Urban areas were classified from pre-event interferometric coherence data. The affected areas from the earthquake were detected with the normalized difference (ND between the pre- and co-event interferometric coherence. The results presented three damage types; namely, damage to buildings caused by ground motion, liquefaction, and landslides. The overall accuracy (94% of the confusion matrix was excellent. Results for urban areas were divided into three damage levels (e.g., none–slight, slight–heavy, heavy–destructive at a high (90% overall accuracy level. Moreover, data on buildings damaged by liquefaction and landslides were in good agreement with field survey information. Overall, this study illustrates an effective damage assessment mapping approach that can support post-earthquake management activities for future events, especially in areas where geographical data are sparse.

  4. Accuracy assessment of high-rate GPS measurements for seismology

    Science.gov (United States)

    Elosegui, P.; Davis, J. L.; Ekström, G.

    2007-12-01

    Analysis of GPS measurements with a controlled laboratory system, built to simulate the ground motions caused by tectonic earthquakes and other transient geophysical signals such as glacial earthquakes, enables us to assess the technique of high-rate GPS. The root-mean-square (rms) position error of this system when undergoing realistic simulated seismic motions is 0.05~mm, with maximum position errors of 0.1~mm, thus providing "ground truth" GPS displacements. We have acquired an extensive set of high-rate GPS measurements while inducing seismic motions on a GPS antenna mounted on this system with a temporal spectrum similar to real seismic events. We found that, for a particular 15-min-long test event, the rms error of the 1-Hz GPS position estimates was 2.5~mm, with maximum position errors of 10~mm, and the error spectrum of the GPS estimates was approximately flicker noise. These results may however represent a best-case scenario since they were obtained over a short (~10~m) baseline, thereby greatly mitigating baseline-dependent errors, and when the number and distribution of satellites on the sky was good. For example, we have determined that the rms error can increase by a factor of 2--3 as the GPS constellation changes throughout the day, with an average value of 3.5~mm for eight identical, hourly-spaced, consecutive test events. The rms error also increases with increasing baseline, as one would expect, with an average rms error for a ~1400~km baseline of 9~mm. We will present an assessment of the accuracy of high-rate GPS based on these measurements, discuss the implications of this study for seismology, and describe new applications in glaciology.

  5. Non-interferometric determination of optical anisotropy in highly-oriented fibres using transport intensity equation technique

    Science.gov (United States)

    Sokkar, T. Z. N.; El-Farahaty, K. A.; El-Bakary, M. A.; Raslan, M. I.; Omar, E. Z.; Hamza, A. A.

    2018-03-01

    The optical setup of the transport intensity equation (TIE) technique is developed to be valid for measuring the optical properties of the highly-oriented anisotropic fibres. This development is based on the microstructure models of the highly-oriented anisotropic fibres and the principle of anisotropy. We provide the setup of TIE technique with polarizer which is controlled via stepper motor. This developed technique is used to investigate the refractive indices in the parallel and perpendicular polarization directions of light for the highly-oriented poly (ethylene terephthalate) (PET) fibres and hence its birefringence. The obtained results through the developed TIE technique for PET fibre are compared with that determined experimentally using the Mach-Zehnder interferometer under the same conditions. The comparison shows a good agreement between the obtained results from the developed technique and that obtained from the Mach-Zehnder interferometer technique.

  6. Interferometric redatuming by sparse inversion

    OpenAIRE

    Van der Neut, J.; Herrmann, F.J.

    2012-01-01

    Assuming that transmission responses are known between the surface and a particular depth level in the subsurface, seismic sources can be effectively mapped to this level by a process called interferometric redatuming. After redatuming, the obtained wavefields can be used for imaging below this particular depth level. Interferometric redatuming consists of two steps, namely (i) the decomposition of the observed wavefields into downgoing and upgoing constituents and (ii) a multidimensional dec...

  7. Accuracy assessment of cadastral maps using high resolution aerial photos

    Directory of Open Access Journals (Sweden)

    Alwan Imzahim

    2018-01-01

    Full Text Available A cadastral map is a map that shows the boundaries and ownership of land parcels. Some cadastral maps show additional details, such as survey district names, unique identifying numbers for parcels, certificate of title numbers, positions of existing structures, section or lot numbers and their respective areas, adjoining and adjacent street names, selected boundary dimensions and references to prior maps. In Iraq / Baghdad Governorate, the main problem is that the cadastral maps are georeferenced to a local geodetic datum known as Clark 1880 while the widely used reference system for navigation purpose (GPS and GNSS and uses Word Geodetic System 1984 (WGS84 as a base reference datum. The objective of this paper is to produce a cadastral map with scale 1:500 (metric scale by using aerial photographs 2009 with high ground spatial resolution 10 cm reference WGS84 system. The accuracy assessment for the cadastral maps updating approach to urban large scale cadastral maps (1:500-1:1000 was ± 0.115 meters; which complies with the American Social for Photogrammetry and Remote Sensing Standards (ASPRS.

  8. Determination of UAV position using high accuracy navigation platform

    Directory of Open Access Journals (Sweden)

    Ireneusz Kubicki

    2016-07-01

    Full Text Available The choice of navigation system for mini UAV is very important because of its application and exploitation, particularly when the installed on it a synthetic aperture radar requires highly precise information about an object’s position. The presented exemplary solution of such a system draws attention to the possible problems associated with the use of appropriate technology, sensors, and devices or with a complete navigation system. The position and spatial orientation errors of the measurement platform influence on the obtained SAR imaging. Both, turbulences and maneuvers performed during flight cause the changes in the position of the airborne object resulting in deterioration or lack of images from SAR. Consequently, it is necessary to perform operations for reducing or eliminating the impact of the sensors’ errors on the UAV position accuracy. You need to look for compromise solutions between newer better technologies and in the field of software. Keywords: navigation systems, unmanned aerial vehicles, sensors integration

  9. A high resolution interferometric method to measure local swelling due to CO2 exposure in coal and shale

    NARCIS (Netherlands)

    Pluymakers, A.; Liu, J.; Kohler, F.; Renard, F.; Dysthe, D.

    2018-01-01

    We present an experimental method to study time-dependent, CO2-induced, local topography changes in mm-sized composite samples, plus results showing heterogeneous swelling of coal and shale on the nano- to micrometer scale. These results were obtained using high resolution interferometry

  10. Modified sine bar device measures small angles with high accuracy

    Science.gov (United States)

    Thekaekara, M.

    1968-01-01

    Modified sine bar device measures small angles with enough accuracy to calibrate precision optical autocollimators. The sine bar is a massive bar of steel supported by two cylindrical rods at one end and one at the other.

  11. Interferometric Observations of the SiO High J Transition Maser associated with VY Canis Majoris with the Submillimeter Array

    Science.gov (United States)

    Shinnaga, H.; Moran, J. M.; Young, K. H.; Ho, P. T. P.

    2005-12-01

    We imaged the SiO maser emission of J=5-4 in the v=1 state associated with the peculiar red supergiant VY Canis Majoris using the partially completed Submillimeter Array. We identified seven maser components and measured the relative positions at sub-arcsecond scale in the high J transition for the first time. We have also measured the polarization of these maser components. The strongest maser feature has a linear polarization of ˜ 60%, and its direction of polarization is approximately aligned with the bipolar axis. Such a high degree of polarization suggests that radiative pumping is probably responsible for the maser inversion. Five of the other maser features have significant linear polarization.

  12. Application of seismic interferometric migration for shallow seismic high precision data processing: A case study in the Shenhu area

    Science.gov (United States)

    Wei, Jia; Liu, Huaishan; Xing, Lei; Du, Dong

    2018-02-01

    The stability of submarine geological structures has a crucial influence on the construction of offshore engineering projects and the exploitation of seabed resources. Marine geologists should possess a detailed understanding of common submarine geological hazards. Current marine seismic exploration methods are based on the most effective detection technologies. Therefore, current research focuses on improving the resolution and precision of shallow stratum structure detection methods. In this article, the feasibility of shallow seismic structure imaging is assessed by building a complex model, and differences between the seismic interferometry imaging method and the traditional imaging method are discussed. The imaging effect of the model is better for shallow layers than for deep layers because coherent noise produced by this method can result in an unsatisfactory imaging effect for deep layers. The seismic interference method has certain advantages for geological structural imaging of shallow submarine strata, which indicates continuous horizontal events, a high resolution, a clear fault, and an obvious structure boundary. The effects of the actual data applied to the Shenhu area can fully illustrate the advantages of the method. Thus, this method has the potential to provide new insights for shallow submarine strata imaging in the area.

  13. Measurement system with high accuracy for laser beam quality.

    Science.gov (United States)

    Ke, Yi; Zeng, Ciling; Xie, Peiyuan; Jiang, Qingshan; Liang, Ke; Yang, Zhenyu; Zhao, Ming

    2015-05-20

    Presently, most of the laser beam quality measurement system collimates the optical path manually with low efficiency and low repeatability. To solve these problems, this paper proposed a new collimated method to improve the reliability and accuracy of the measurement results. The system accuracy controlled the position of the mirror to change laser beam propagation direction, which can realize the beam perpendicularly incident to the photosurface of camera. The experiment results show that the proposed system has good repeatability and the measuring deviation of M2 factor is less than 0.6%.

  14. Diagnostic accuracy of high-definition CT coronary angiography in high-risk patients

    International Nuclear Information System (INIS)

    Iyengar, S.S.; Morgan-Hughes, G.; Ukoumunne, O.; Clayton, B.; Davies, E.J.; Nikolaou, V.; Hyde, C.J.; Shore, A.C.; Roobottom, C.A.

    2016-01-01

    Aim: To assess the diagnostic accuracy of computed tomography coronary angiography (CTCA) using a combination of high-definition CT (HD-CTCA) and high level of reader experience, with invasive coronary angiography (ICA) as the reference standard, in high-risk patients for the investigation of coronary artery disease (CAD). Materials and methods: Three hundred high-risk patients underwent HD-CTCA and ICA. Independent experts evaluated the images for the presence of significant CAD, defined primarily as the presence of moderate (≥50%) stenosis and secondarily as the presence of severe (≥70%) stenosis in at least one coronary segment, in a blinded fashion. HD-CTCA was compared to ICA as the reference standard. Results: No patients were excluded. Two hundred and six patients (69%) had moderate and 178 (59%) had severe stenosis in at least one vessel at ICA. The sensitivity, specificity, positive predictive value, and negative predictive value were 97.1%, 97.9%, 99% and 93.9% for moderate stenosis, and 98.9%, 93.4%, 95.7% and 98.3%, for severe stenosis, on a per-patient basis. Conclusion: The combination of HD-CTCA and experienced readers applied to a high-risk population, results in high diagnostic accuracy comparable to ICA. Modern generation CT systems in experienced hands might be considered for an expanded role. - Highlights: • Diagnostic accuracy of High-Definition CT Angiography (HD-CTCA) has been assessed. • Invasive Coronary angiography (ICA) is the reference standard. • Diagnostic accuracy of HD-CTCA is comparable to ICA. • Diagnostic accuracy is not affected by coronary calcium or stents. • HD-CTCA provides a non-invasive alternative in high-risk patients.

  15. High-accuracy user identification using EEG biometrics.

    Science.gov (United States)

    Koike-Akino, Toshiaki; Mahajan, Ruhi; Marks, Tim K; Ye Wang; Watanabe, Shinji; Tuzel, Oncel; Orlik, Philip

    2016-08-01

    We analyze brain waves acquired through a consumer-grade EEG device to investigate its capabilities for user identification and authentication. First, we show the statistical significance of the P300 component in event-related potential (ERP) data from 14-channel EEGs across 25 subjects. We then apply a variety of machine learning techniques, comparing the user identification performance of various different combinations of a dimensionality reduction technique followed by a classification algorithm. Experimental results show that an identification accuracy of 72% can be achieved using only a single 800 ms ERP epoch. In addition, we demonstrate that the user identification accuracy can be significantly improved to more than 96.7% by joint classification of multiple epochs.

  16. High Accuracy Nonlinear Control and Estimation for Machine Tool Systems

    DEFF Research Database (Denmark)

    Papageorgiou, Dimitrios

    Component mass production has been the backbone of industry since the second industrial revolution, and machine tools are producing parts of widely varying size and design complexity. The ever-increasing level of automation in modern manufacturing processes necessitates the use of more...... sophisticated machine tool systems that are adaptable to different workspace conditions, while at the same time being able to maintain very narrow workpiece tolerances. The main topic of this thesis is to suggest control methods that can maintain required manufacturing tolerances, despite moderate wear and tear....... The purpose is to ensure that full accuracy is maintained between service intervals and to advice when overhaul is needed. The thesis argues that quality of manufactured components is directly related to the positioning accuracy of the machine tool axes, and it shows which low level control architectures...

  17. Methodology for GPS Synchronization Evaluation with High Accuracy

    OpenAIRE

    Li Zan; Braun Torsten; Dimitrova Desislava

    2015-01-01

    Clock synchronization in the order of nanoseconds is one of the critical factors for time based localization. Currently used time synchronization methods are developed for the more relaxed needs of network operation. Their usability for positioning should be carefully evaluated. In this paper we are particularly interested in GPS based time synchronization. To judge its usability for localization we need a method that can evaluate the achieved time synchronization with nanosecond accuracy. Ou...

  18. Methodology for GPS Synchronization Evaluation with High Accuracy

    OpenAIRE

    Li, Zan; Braun, Torsten; Dimitrova, Desislava Cvetanova

    2015-01-01

    Clock synchronization in the order of nanoseconds is one of the critical factors for time-based localization. Currently used time synchronization methods are developed for the more relaxed needs of network operation. Their usability for positioning should be carefully evaluated. In this paper, we are particularly interested in GPS-based time synchronization. To judge its usability for localization we need a method that can evaluate the achieved time synchronization with nanosecond accuracy. O...

  19. MEMS Gyroscope with Interferometric Detection, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is a novel MEMS gyroscope that uses micro-interferometric detection to measure the motion of the proof mass. Using an interferometric...

  20. Interferometric reflection moire

    Science.gov (United States)

    Sciammarella, Cesar A.; Combell, Olivier

    1995-06-01

    A new reflection moire technique is introduced in this paper. The basic equations that relate the measurement of slopes to the basic geometric and optical parameters of the system are derived. The sensitivity and accuracy of the method are discussed. Examples of application to the study of silicon wafers and electronic chips are given.

  1. Research on Horizontal Accuracy Method of High Spatial Resolution Remotely Sensed Orthophoto Image

    Science.gov (United States)

    Xu, Y. M.; Zhang, J. X.; Yu, F.; Dong, S.

    2018-04-01

    At present, in the inspection and acceptance of high spatial resolution remotly sensed orthophoto image, the horizontal accuracy detection is testing and evaluating the accuracy of images, which mostly based on a set of testing points with the same accuracy and reliability. However, it is difficult to get a set of testing points with the same accuracy and reliability in the areas where the field measurement is difficult and the reference data with high accuracy is not enough. So it is difficult to test and evaluate the horizontal accuracy of the orthophoto image. The uncertainty of the horizontal accuracy has become a bottleneck for the application of satellite borne high-resolution remote sensing image and the scope of service expansion. Therefore, this paper proposes a new method to test the horizontal accuracy of orthophoto image. This method using the testing points with different accuracy and reliability. These points' source is high accuracy reference data and field measurement. The new method solves the horizontal accuracy detection of the orthophoto image in the difficult areas and provides the basis for providing reliable orthophoto images to the users.

  2. Innovative Fiber-Optic Gyroscopes (FOGs) for High Accuracy Space Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's future science and exploratory missions will require much lighter, smaller, and longer life rate sensors that can provide high accuracy navigational...

  3. High Accuracy Positioning using Jet Thrusters for Quadcopter

    Directory of Open Access Journals (Sweden)

    Pi ChenHuan

    2018-01-01

    Full Text Available A quadcopter is equipped with four additional jet thrusters on its horizontal plane and vertical to each other in order to improve the maneuverability and positioning accuracy of quadcopter. A dynamic model of the quadcopter with jet thrusters is derived and two controllers are implemented in simulation, one is a dual loop state feedback controller for pose control and another is an auxiliary jet thruster controller for accurate positioning. Step response simulations showed that the jet thruster can control the quadcopter with less overshoot compared to the conventional one. Over 10s loiter simulation with disturbance, the quadcopter with jet thruster decrease 85% of RMS error of horizontal disturbance compared to a conventional quadcopter with only a dual loop state feedback controller. The jet thruster controller shows the possibility for further accurate in the field of quadcopter positioning.

  4. High-accuracy contouring using projection moiré

    Science.gov (United States)

    Sciammarella, Cesar A.; Lamberti, Luciano; Sciammarella, Federico M.

    2005-09-01

    Shadow and projection moiré are the oldest forms of moiré to be used in actual technical applications. In spite of this fact and the extensive number of papers that have been published on this topic, the use of shadow moiré as an accurate tool that can compete with alternative devices poses very many problems that go to the very essence of the mathematical models used to obtain contour information from fringe pattern data. In this paper some recent developments on the projection moiré method are presented. Comparisons between the results obtained with the projection method and the results obtained by mechanical devices that operate with contact probes are presented. These results show that the use of projection moiré makes it possible to achieve the same accuracy that current mechanical touch probe devices can provide.

  5. Interferometric redatuming by sparse inversion

    Science.gov (United States)

    van der Neut, Joost; Herrmann, Felix J.

    2013-02-01

    Assuming that transmission responses are known between the surface and a particular depth level in the subsurface, seismic sources can be effectively mapped to this level by a process called interferometric redatuming. After redatuming, the obtained wavefields can be used for imaging below this particular depth level. Interferometric redatuming consists of two steps, namely (i) the decomposition of the observed wavefields into downgoing and upgoing constituents and (ii) a multidimensional deconvolution of the upgoing constituents with the downgoing constituents. While this method works in theory, sensitivity to noise and artefacts due to incomplete acquisition require a different formulation. In this letter, we demonstrate the benefits of formulating the two steps that undergird interferometric redatuming in terms of a transform-domain sparsity-promoting program. By exploiting compressibility of seismic wavefields in the curvelet domain, the method not only becomes robust with respect to noise but we are also able to remove certain artefacts while preserving the frequency content. Although we observe improvements when we promote sparsity in the redatumed data space, we expect better results when interferometric redatuming would be combined or integrated with least-squares migration with sparsity promotion in the image space.

  6. Cross-calibration of interferometric SAR data

    DEFF Research Database (Denmark)

    Dall, Jørgen

    2003-01-01

    Generation of digital elevation models from interferometric synthetic aperture radar (SAR) data is a well established technique. Achieving a high geometric fidelity calls for a calibration accounting for inaccurate navigation data and system parameters as well as system imperfections. Fully...... automated calibration techniques are preferable, especially for operational mapping. The author presents one such technique, called cross-calibration. Though developed for single-pass interferometry, it may be applicable to multi-pass interferometry, too. Cross-calibration requires stability during mapping...... ground control point is often needed. The paper presents the principles and mathematics of the cross-calibration technique and illustrates its successful application to EMISAR data....

  7. Theory, analysis and design of RF interferometric sensors

    CERN Document Server

    Nguyen, Cam

    2012-01-01

    Theory, Analysis and Design of RF Interferometric Sensors presents the theory, analysis and design of RF interferometric sensors. RF interferometric sensors are attractive for various sensing applications that require every fine resolution and accuracy as well as fast speed. The book also presents two millimeter-wave interferometric sensors realized using RF integrated circuits. The developed millimeter-wave homodyne sensor shows sub-millimeter resolution in the order of 0.05 mm without correction for the non-linear phase response of the sensor's quadrature mixer. The designed millimeter-wave double-channel homodyne sensor provides a resolution of only 0.01 mm, or 1/840th of the operating wavelength, and can inherently suppress the non-linearity of the sensor's quadrature mixer. The experimental results of displacement and velocity measurement are presented as a way to demonstrate the sensing ability of the RF interferometry and to illustrate its many possible applications in sensing. The book is succinct, ye...

  8. Compact, High Accuracy CO2 Monitor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovative Research Phase I proposal seeks to develop a low cost, robust, highly precise and accurate CO2 monitoring system. This system will...

  9. Compact, High Accuracy CO2 Monitor, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovative Research Phase II proposal seeks to develop a low cost, robust, highly precise and accurate CO2 monitoring system. This system will...

  10. High-accuracy Subdaily ERPs from the IGS

    Science.gov (United States)

    Ray, J. R.; Griffiths, J.

    2012-04-01

    Since November 2000 the International GNSS Service (IGS) has published Ultra-rapid (IGU) products for near real-time (RT) and true real-time applications. They include satellite orbits and clocks, as well as Earth rotation parameters (ERPs) for a sliding 48-hr period. The first day of each update is based on the most recent GPS and GLONASS observational data from the IGS hourly tracking network. At the time of release, these observed products have an initial latency of 3 hr. The second day of each update consists of predictions. So the predictions between about 3 and 9 hr into the second half are relevant for true RT uses. Originally updated twice daily, the IGU products since April 2004 have been issued every 6 hr, at 3, 9, 15, and 21 UTC. Up to seven Analysis Centers (ACs) contribute to the IGU combinations. Two sets of ERPs are published with each IGU update, observed values at the middle epoch of the first half and predicted values at the middle epoch of the second half. The latency of the near RT ERPs is 15 hr while the predicted ERPs, based on projections of each AC's most recent determinations, are issued 9 hr ahead of their reference epoch. While IGU ERPs are issued every 6 hr, each set represents an integrated estimate over the surrounding 24 hr. So successive values are temporally correlated with about 75% of the data being common; this fact should be taken into account in user assimilations. To evaluate the accuracy of these near RT and predicted ERPs, they have been compared to the IGS Final ERPs, available about 11 to 17 d after data collection. The IGU products improved dramatically in the earlier years but since about 2008.0 the performance has been stable and excellent. During the last three years, RMS differences for the observed IGU ERPs have been about 0.036 mas and 0.0101 ms for each polar motion component and LOD respectively. (The internal precision of the reference IGS ERPs over the same period is about 0.016 mas for polar motion and 0

  11. AN ASSESSMENT OF SPACEBORNE NEAR-NADIR INTERFEROMETRIC SAR PERFORMANCE OVER INLAND WATERS WITH REAL

    Directory of Open Access Journals (Sweden)

    H. Tan

    2018-04-01

    Full Text Available Elevation measurements of the continental water surface have been poorly collected with in situ measurements or occasionally with conventional altimeters with low accuracy. Techniques using InSAR at near-nadir angles to measure the inland water elevation with large swath and with high accuracy have been proposed, for instance, the WSOA on Jason 2 and the KaRIn on SWOT. However, the WSOA was abandoned unfortunately and the SWOT is planned to be launched in 2021. In this paper, we show real acquisitions of the first spaceborne InSAR of such kind, the Interferometric Imaging Radar Altimeter (InIRA, which has been working on Tiangong II spacecraft since 2016. We used the 90-m SRTM DEM as a reference to estimate the phase offset, and then an empirical calibration model was used to correct the baseline errors.

  12. An Assessment of Spaceborne Near-Nadir Interferometric SAR Performance Over Inland Waters with Real

    Science.gov (United States)

    Tan, H.; Li, S. Y.; Liu, Z. W.

    2018-04-01

    Elevation measurements of the continental water surface have been poorly collected with in situ measurements or occasionally with conventional altimeters with low accuracy. Techniques using InSAR at near-nadir angles to measure the inland water elevation with large swath and with high accuracy have been proposed, for instance, the WSOA on Jason 2 and the KaRIn on SWOT. However, the WSOA was abandoned unfortunately and the SWOT is planned to be launched in 2021. In this paper, we show real acquisitions of the first spaceborne InSAR of such kind, the Interferometric Imaging Radar Altimeter (InIRA), which has been working on Tiangong II spacecraft since 2016. We used the 90-m SRTM DEM as a reference to estimate the phase offset, and then an empirical calibration model was used to correct the baseline errors.

  13. Noise analysis of the measurement of group delay in Fourier white-light interferometric cross correlation

    International Nuclear Information System (INIS)

    Laude, Vincent

    2002-01-01

    The problem of noise analysis in measuring the group delay introduced by a dispersive optical element by use of white-light interferometric cross correlation is investigated. Two noise types, detection noise and position noise, are specifically analyzed. Detection noise is shown to be highly sensitive to the spectral content of the white-light source at the frequency considered and to the temporal acquisition window. Position noise, which arises from the finite accuracy of the measurement of the scanning mirror's position, can severely damage the estimation of the group delay. Such is shown to be the case for fast Fourier transform-based estimation algorithms. A new algorithm that is insensitive to scanning delay errors is proposed, and subfemtosecond accuracy is obtained without any postprocessing

  14. Accuracy of Handheld Blood Glucose Meters at High Altitude

    NARCIS (Netherlands)

    de Mol, Pieter; Krabbe, Hans G.; de Vries, Suzanna T.; Fokkert, Marion J.; Dikkeschei, Bert D.; Rienks, Rienk; Bilo, Karin M.; Bilo, Henk J. G.

    2010-01-01

    Background: Due to increasing numbers of people with diabetes taking part in extreme sports (e. g., high-altitude trekking), reliable handheld blood glucose meters (BGMs) are necessary. Accurate blood glucose measurement under extreme conditions is paramount for safe recreation at altitude. Prior

  15. Innovative Fiber-Optic Gyroscopes (FOGs) for High Accuracy Space Applications, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This project aims to develop a compact, highly innovative Inertial Reference/Measurement Unit (IRU/IMU) that pushes the state-of-the-art in high accuracy performance...

  16. Modeling and Validation of Performance Limitations for the Optimal Design of Interferometric and Intensity-Modulated Fiber Optic Displacement Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Moro, Erik A. [Los Alamos National Laboratory

    2012-06-07

    Optical fiber sensors offer advantages over traditional electromechanical sensors, making them particularly well-suited for certain measurement applications. Generally speaking, optical fiber sensors respond to a desired measurand through modulation of an optical signal's intensity, phase, or wavelength. Practically, non-contacting fiber optic displacement sensors are limited to intensity-modulated and interferometric (or phase-modulated) methodologies. Intensity-modulated fiber optic displacement sensors relate target displacement to a power measurement. The simplest intensity-modulated sensor architectures are not robust to environmental and hardware fluctuations, since such variability may cause changes in the measured power level that falsely indicate target displacement. Differential intensity-modulated sensors have been implemented, offering robustness to such intensity fluctuations, and the speed of these sensors is limited only by the combined speed of the photodetection hardware and the data acquisition system (kHz-MHz). The primary disadvantages of intensity-modulated sensing are the relatively low accuracy (?m-mm for low-power sensors) and the lack of robustness, which consequently must be designed, often with great difficulty, into the sensor's architecture. White light interferometric displacement sensors, on the other hand, offer increased accuracy and robustness. Unlike their monochromatic-interferometer counterparts, white light interferometric sensors offer absolute, unambiguous displacement measurements over large displacement ranges (cm for low-power, 5 mW, sources), necessitating no initial calibration, and requiring no environmental or feedback control. The primary disadvantage of white light interferometric displacement sensors is that their utility in dynamic testing scenarios is limited, both by hardware bandwidth and by their inherent high-sensitivity to Doppler-effects. The decision of whether to use either an intensity

  17. A High-Throughput, High-Accuracy System-Level Simulation Framework for System on Chips

    Directory of Open Access Journals (Sweden)

    Guanyi Sun

    2011-01-01

    Full Text Available Today's System-on-Chips (SoCs design is extremely challenging because it involves complicated design tradeoffs and heterogeneous design expertise. To explore the large solution space, system architects have to rely on system-level simulators to identify an optimized SoC architecture. In this paper, we propose a system-level simulation framework, System Performance Simulation Implementation Mechanism, or SPSIM. Based on SystemC TLM2.0, the framework consists of an executable SoC model, a simulation tool chain, and a modeling methodology. Compared with the large body of existing research in this area, this work is aimed at delivering a high simulation throughput and, at the same time, guaranteeing a high accuracy on real industrial applications. Integrating the leading TLM techniques, our simulator can attain a simulation speed that is not slower than that of the hardware execution by a factor of 35 on a set of real-world applications. SPSIM incorporates effective timing models, which can achieve a high accuracy after hardware-based calibration. Experimental results on a set of mobile applications proved that the difference between the simulated and measured results of timing performance is within 10%, which in the past can only be attained by cycle-accurate models.

  18. Impact of a highly detailed emission inventory on modeling accuracy

    Science.gov (United States)

    Taghavi, M.; Cautenet, S.; Arteta, J.

    2005-03-01

    During Expérience sur Site pour COntraindre les Modèles de Pollution atmosphérique et de Transport d'Emissions (ESCOMPTE) campaign (June 10 to July 14, 2001), two pollution events observed during an intensive measurement period (IOP2a and IOP2b) have been simulated. The comprehensive Regional Atmospheric Modeling Systems (RAMS) model, version 4.3, coupled online with a chemical module including 29 species is used to follow the chemistry of a polluted zone over Southern France. This online method takes advantage of a parallel code and use of the powerful computer SGI 3800. Runs are performed with two emission inventories: the Emission Pre Inventory (EPI) and the Main Emission Inventory (MEI). The latter is more recent and has a high resolution. The redistribution of simulated chemical species (ozone and nitrogen oxides) is compared with aircraft and surface station measurements for both runs at regional scale. We show that the MEI inventory is more efficient than the EPI in retrieving the redistribution of chemical species in space (three-dimensional) and time. In surface stations, MEI is superior especially for primary species, like nitrogen oxides. The ozone pollution peaks obtained from an inventory, such as EPI, have a large uncertainty. To understand the realistic geographical distribution of pollutants and to obtain a good order of magnitude in ozone concentration (in space and time), a high-resolution inventory like MEI is necessary. Coupling RAMS-Chemistry with MEI provides a very efficient tool able to simulate pollution plumes even in a region with complex circulations, such as the ESCOMPTE zone.

  19. Switched-capacitor techniques for high-accuracy filter and ADC design

    NARCIS (Netherlands)

    Quinn, P.J.; Roermund, van A.H.M.

    2007-01-01

    Switched capacitor (SC) techniques are well proven to be excellent candidates for implementing critical analogue functions with high accuracy, surpassing other analogue techniques when embedded in mixed-signal CMOS VLSI. Conventional SC circuits are primarily limited in accuracy by a) capacitor

  20. High accuracy laboratory spectroscopy to support active greenhouse gas sensing

    Science.gov (United States)

    Long, D. A.; Bielska, K.; Cygan, A.; Havey, D. K.; Okumura, M.; Miller, C. E.; Lisak, D.; Hodges, J. T.

    2011-12-01

    Recent carbon dioxide (CO2) remote sensing missions have set precision targets as demanding as 0.25% (1 ppm) in order to elucidate carbon sources and sinks [1]. These ambitious measurement targets will require the most precise body of spectroscopic reference data ever assembled. Active sensing missions will be especially susceptible to subtle line shape effects as the narrow bandwidth of these measurements will greatly limit the number of spectral transitions which are employed in retrievals. In order to assist these remote sensing missions we have employed frequency-stabilized cavity ring-down spectroscopy (FS-CRDS) [2], a high-resolution, ultrasensitive laboratory technique, to measure precise line shape parameters for transitions of O2, CO2, and other atmospherically-relevant species within the near-infrared. These measurements have led to new HITRAN-style line lists for both 16O2 [3] and rare isotopologue [4] transitions in the A-band. In addition, we have performed detailed line shape studies of CO2 transitions near 1.6 μm under a variety of broadening conditions [5]. We will address recent measurements in these bands as well as highlight recent instrumental improvements to the FS-CRDS spectrometer. These improvements include the use of the Pound-Drever-Hall locking scheme, a high bandwidth servo which enables measurements to be made at rates greater than 10 kHz [6]. In addition, an optical frequency comb will be utilized as a frequency reference, which should allow for transition frequencies to be measured with uncertainties below 10 kHz (3×10-7 cm-1). [1] C. E. Miller, D. Crisp, P. L. DeCola, S. C. Olsen, et al., J. Geophys. Res.-Atmos. 112, D10314 (2007). [2] J. T. Hodges, H. P. Layer, W. W. Miller, G. E. Scace, Rev. Sci. Instrum. 75, 849-863 (2004). [3] D. A. Long, D. K. Havey, M. Okumura, C. E. Miller, et al., J. Quant. Spectrosc. Radiat. Transfer 111, 2021-2036 (2010). [4] D. A. Long, D. K. Havey, S. S. Yu, M. Okumura, et al., J. Quant. Spectrosc

  1. The accuracy of QCD perturbation theory at high energies

    CERN Document Server

    Dalla Brida, Mattia; Korzec, Tomasz; Ramos, Alberto; Sint, Stefan; Sommer, Rainer

    2016-01-01

    We discuss the determination of the strong coupling $\\alpha_\\mathrm{\\overline{MS}}^{}(m_\\mathrm{Z})$ or equivalently the QCD $\\Lambda$-parameter. Its determination requires the use of perturbation theory in $\\alpha_s(\\mu)$ in some scheme, $s$, and at some energy scale $\\mu$. The higher the scale $\\mu$ the more accurate perturbation theory becomes, owing to asymptotic freedom. As one step in our computation of the $\\Lambda$-parameter in three-flavor QCD, we perform lattice computations in a scheme which allows us to non-perturbatively reach very high energies, corresponding to $\\alpha_s = 0.1$ and below. We find that perturbation theory is very accurate there, yielding a three percent error in the $\\Lambda$-parameter, while data around $\\alpha_s \\approx 0.2$ is clearly insufficient to quote such a precision. It is important to realize that these findings are expected to be generic, as our scheme has advantageous properties regarding the applicability of perturbation theory.

  2. A New Three-Dimensional High-Accuracy Automatic Alignment System For Single-Mode Fibers

    Science.gov (United States)

    Yun-jiang, Rao; Shang-lian, Huang; Ping, Li; Yu-mei, Wen; Jun, Tang

    1990-02-01

    In order to achieve the low-loss splices of single-mode fibers, a new three-dimension high-accuracy automatic alignment system for single -mode fibers has been developed, which includes a new-type three-dimension high-resolution microdisplacement servo stage driven by piezoelectric elements, a new high-accuracy measurement system for the misalignment error of the fiber core-axis, and a special single chip microcomputer processing system. The experimental results show that alignment accuracy of ±0.1 pin with a movable stroke of -±20μm has been obtained. This new system has more advantages than that reported.

  3. Accuracy Assessment for the Three-Dimensional Coordinates by High-Speed Videogrammetric Measurement

    Directory of Open Access Journals (Sweden)

    Xianglei Liu

    2018-01-01

    Full Text Available High-speed CMOS camera is a new kind of transducer to make the videogrammetric measurement for monitoring the displacement of high-speed shaking table structure. The purpose of this paper is to validate the three-dimensional coordinate accuracy of the shaking table structure acquired from the presented high-speed videogrammetric measuring system. In the paper, all of the key intermediate links are discussed, including the high-speed CMOS videogrammetric measurement system, the layout of the control network, the elliptical target detection, and the accuracy validation of final 3D spatial results. Through the accuracy analysis, the submillimeter accuracy can be made for the final the three-dimensional spatial coordinates which certify that the proposed high-speed videogrammetric technique is a better alternative technique which can replace the traditional transducer technique for monitoring the dynamic response for the shaking table structure.

  4. High-accuracy determination for optical indicatrix rotation in ferroelectric DTGS

    OpenAIRE

    O.S.Kushnir; O.A.Bevz; O.G.Vlokh

    2000-01-01

    Optical indicatrix rotation in deuterated ferroelectric triglycine sulphate is studied with the high-accuracy null-polarimetric technique. The behaviour of the effect in ferroelectric phase is referred to quadratic spontaneous electrooptics.

  5. New formulation for interferometric synthetic aperture radar for terrain mapping

    Science.gov (United States)

    Jakowatz, Charles V., Jr.; Wahl, Daniel E.; Eichel, Paul H.; Thompson, Paul A.

    1994-06-01

    The subject of interferometric synthetic aperture radar (IFSAR) for high-accuracy terrain elevation mapping continues to gain importance in the arena of radar signal processing. Applications to problems in precision terrain-aided guidance and automatic target recognition, as well as a variety of civil applications, are being studied by a number of researchers. Not unlike many other areas of SAR processing, the subject of IFSAR can, at first glance, appear to be somewhat mysterious. In this paper we show how the mathematics of IFSAR for terrain elevation mapping using a pair of spotlight mode SAR collections can be derived in a very straightforward manner. Here, we employ an approach that relies entirely on Fourier transforms, and utilizes no reference to range equations or Doppler concepts. The result is a simplified explanation of the fundamentals of interferometry, including an easily-seen link between image domain phase difference and terrain elevation height. The derivation builds upon previous work by the authors in which a framework for spotlight mode SAR image formation based on an analogy to 3D computerized axial tomography (CAT) was developed. After outlining the major steps in the mathematics, we show how a computer simulator which utilizes 3D Fourier transforms can be constructed that demonstrates all of the major aspects of IFSAR from spotlight mode collections.

  6. Interferometric crosstalk reduction by phase scrambling

    NARCIS (Netherlands)

    Tafur Monroy, I.; Tangdiongga, E.; Jonker, R.J.W.; Waardt, de H.

    2000-01-01

    Interferometric crosstalk, arising from the detection of undesired signals at the same nominal wavelength, may introduce large power penalties and bit-error rate (BER) floor significantly restricting the scalability of optical networks. In this paper, interferometric crosstalk reduction in optical

  7. Symmetry evaluation for an interferometric fiber optic gyro coil utilizing a bidirectional distributed polarization measurement system.

    Science.gov (United States)

    Peng, Feng; Li, Chuang; Yang, Jun; Hou, Chengcheng; Zhang, Haoliang; Yu, Zhangjun; Yuan, Yonggui; Li, Hanyang; Yuan, Libo

    2017-07-10

    We propose a dual-channel measurement system for evaluating the optical path symmetry of an interferometric fiber optic gyro (IFOG) coil. Utilizing a bidirectional distributed polarization measurement system, the forward and backward transmission performances of an IFOG coil are characterized simultaneously by just a one-time measurement. The simple but practical configuration is composed of a bidirectional Mach-Zehnder interferometer and multichannel transmission devices connected to the IFOG coil under test. The static and dynamic temperature results of the IFOG coil reveal that its polarization-related symmetric properties can be effectively obtained with high accuracy. The optical path symmetry investigation is highly beneficial in monitoring and improving the winding technology of an IFOG coil and reducing the nonreciprocal effect of an IFOG.

  8. X-ray interferometric Fourier holography

    International Nuclear Information System (INIS)

    Balyan, M.K.

    2016-01-01

    The X-ray interferometric Fourier holography is proposed and theoretically investigated. Fourier The X-ray interferometric Young fringes and object image reconstruction are investigated. It is shown that the interference pattern of two slits formed on the exit surface of the crystal-analyzer (the third plate of the interferometer) is the X-ray interferometric Young fringes. An expression for X-ray interferometric Young fringes period is obtained. The subsequent reconstruction of the slit image as an object is performed by means of Fourier transform of the intensity distribution on the hologram. Three methods of reconstruction of the amplitude transmission complex function of the object are presented: analytical - approximate method, method of iteration and step by step method. As an example the X-ray Fourier interferometric hologram recording and the complex amplitude transmission function reconstruction for a beryllium circular wire are considered

  9. The effect of pattern overlap on the accuracy of high resolution electron backscatter diffraction measurements

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Vivian, E-mail: v.tong13@imperial.ac.uk [Department of Materials, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom); Jiang, Jun [Department of Materials, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom); Wilkinson, Angus J. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Britton, T. Ben [Department of Materials, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom)

    2015-08-15

    High resolution, cross-correlation-based, electron backscatter diffraction (EBSD) measures the variation of elastic strains and lattice rotations from a reference state. Regions near grain boundaries are often of interest but overlap of patterns from the two grains could reduce accuracy of the cross-correlation analysis. To explore this concern, patterns from the interior of two grains have been mixed to simulate the interaction volume crossing a grain boundary so that the effect on the accuracy of the cross correlation results can be tested. It was found that the accuracy of HR-EBSD strain measurements performed in a FEG-SEM on zirconium remains good until the incident beam is less than 18 nm from a grain boundary. A simulated microstructure was used to measure how often pattern overlap occurs at any given EBSD step size, and a simple relation was found linking the probability of overlap with step size. - Highlights: • Pattern overlap occurs at grain boundaries and reduces HR-EBSD accuracy. • A test is devised to measure the accuracy of HR-EBSD in the presence of overlap. • High pass filters can sometimes, but not generally, improve HR-EBSD measurements. • Accuracy of HR-EBSD remains high until the reference pattern intensity is <72%. • 9% of points near a grain boundary will have significant error for 200nm step size in Zircaloy-4.

  10. The Space Infrared Interferometric Telescope (SPIRIT)

    Science.gov (United States)

    Leisawitz, David T.

    2014-01-01

    The far-infrared astrophysics community is eager to follow up Spitzer and Herschel observations with sensitive, high-resolution imaging and spectroscopy, for such measurements are needed to understand merger-driven star formation and chemical enrichment in galaxies, star and planetary system formation, and the development and prevalence of water-bearing planets. The Space Infrared Interferometric Telescope (SPIRIT) is a wide field-of-view space-based spatio-spectral interferometer designed to operate in the 25 to 400 micron wavelength range. This talk will summarize the SPIRIT mission concept, with a focus on the science that motivates it and the technology that enables it. Without mentioning SPIRIT by name, the astrophysics community through the NASA Astrophysics Roadmap Committee recently recommended this mission as the first in a series of space-based interferometers. Data from a laboratory testbed interferometer will be used to illustrate how the spatio-spectral interferometry technique works.

  11. High-accuracy drilling with an image guided light weight robot: autonomous versus intuitive feed control.

    Science.gov (United States)

    Tauscher, Sebastian; Fuchs, Alexander; Baier, Fabian; Kahrs, Lüder A; Ortmaier, Tobias

    2017-10-01

    Assistance of robotic systems in the operating room promises higher accuracy and, hence, demanding surgical interventions become realisable (e.g. the direct cochlear access). Additionally, an intuitive user interface is crucial for the use of robots in surgery. Torque sensors in the joints can be employed for intuitive interaction concepts. Regarding the accuracy, they lead to a lower structural stiffness and, thus, to an additional error source. The aim of this contribution is to examine, if an accuracy needed for demanding interventions can be achieved by such a system or not. Feasible accuracy results of the robot-assisted process depend on each work-flow step. This work focuses on the determination of the tool coordinate frame. A method for drill axis definition is implemented and analysed. Furthermore, a concept of admittance feed control is developed. This allows the user to control feeding along the planned path by applying a force to the robots structure. The accuracy is researched by drilling experiments with a PMMA phantom and artificial bone blocks. The described drill axis estimation process results in a high angular repeatability ([Formula: see text]). In the first set of drilling results, an accuracy of [Formula: see text] at entrance and [Formula: see text] at target point excluding imaging was achieved. With admittance feed control an accuracy of [Formula: see text] at target point was realised. In a third set twelve holes were drilled in artificial temporal bone phantoms including imaging. In this set-up an error of [Formula: see text] and [Formula: see text] was achieved. The results of conducted experiments show that accuracy requirements for demanding procedures such as the direct cochlear access can be fulfilled with compliant systems. Furthermore, it was shown that with the presented admittance feed control an accuracy of less then [Formula: see text] is achievable.

  12. Calibration Errors in Interferometric Radio Polarimetry

    Science.gov (United States)

    Hales, Christopher A.

    2017-08-01

    Residual calibration errors are difficult to predict in interferometric radio polarimetry because they depend on the observational calibration strategy employed, encompassing the Stokes vector of the calibrator and parallactic angle coverage. This work presents analytic derivations and simulations that enable examination of residual on-axis instrumental leakage and position-angle errors for a suite of calibration strategies. The focus is on arrays comprising alt-azimuth antennas with common feeds over which parallactic angle is approximately uniform. The results indicate that calibration schemes requiring parallactic angle coverage in the linear feed basis (e.g., the Atacama Large Millimeter/submillimeter Array) need only observe over 30°, beyond which no significant improvements in calibration accuracy are obtained. In the circular feed basis (e.g., the Very Large Array above 1 GHz), 30° is also appropriate when the Stokes vector of the leakage calibrator is known a priori, but this rises to 90° when the Stokes vector is unknown. These findings illustrate and quantify concepts that were previously obscure rules of thumb.

  13. Adaptive sensor-based ultra-high accuracy solar concentrator tracker

    Science.gov (United States)

    Brinkley, Jordyn; Hassanzadeh, Ali

    2017-09-01

    Conventional solar trackers use information of the sun's position, either by direct sensing or by GPS. Our method uses the shading of the receiver. This, coupled with nonimaging optics design allows us to achieve ultra-high concentration. Incorporating a sensor based shadow tracking method with a two stage concentration solar hybrid parabolic trough allows the system to maintain high concentration with acute accuracy.

  14. Measurement of morphing wing deflection by a cross-coherence fiber optic interferometric technique

    Science.gov (United States)

    Tomić, Miloš C.; Djinović, Zoran V.; Scheerer, Michael; Petricevic, Slobodan J.

    2018-01-01

    A fiber-optic interferometric technique aimed at measuring the deflection of aircrafts’ morphing wings is presented. The wing deflection induces a strain in the sensing fiber optic coils that are firmly fixed onto the wing. A change of the phase angle of the light propagating through the fiber is measured by an ‘all-in-fiber’ Michelson interferometer based on a 3 × 3 fiber-optic coupler. Two light sources of different coherence lengths and wavelengths are simultaneously used to ensure a wide measurement range and high accuracy. A new technique for determination of the zero deflection point using the cross-correlation of the two interferograms is proposed. The experiments performed on a specimen made of a carbon-fiber-reinforced plastic honeycomb structure demonstrated a relative uncertainty morphing wing deflection.

  15. Interferometric laser imaging for in-flight cloud droplet sizing

    International Nuclear Information System (INIS)

    Dunker, Christina; Roloff, Christoph; Grassmann, Arne

    2016-01-01

    A non-intrusive particle sizing method with a high spatial distribution is used to estimate cloud droplet spectra during flight test campaigns. The interferometric laser imaging for droplet sizing (ILIDS) method derives particle diameters of transparent spheres by evaluating the out-of-focus image patterns. This sizing approach requires a polarized monochromatic light source, a camera including an objective lens with a slit aperture, a synchronization unit and a processing tool for data evaluation. These components are adapted to a flight test environment to enable the microphysical investigation of different cloud genera. The present work addresses the design and specifications of ILIDS system, flight test preparation and selected results obtained in the lower and middle troposphere. The research platform was a Dornier Do228-101 commuter aircraft at the DLR Flight Operation Center in Braunschweig. It was equipped with the required instrumentation including a high-energy laser as the light source. A comprehensive data set of around 71 800 ILIDS images was acquired over the course of five flights. The data evaluation of the characteristic ILIDS fringe patterns relies, among other things, on a relationship between the fringe spacing and the diameter of the particle. The simplest way to extract this information from a pattern is by fringe counting, which is not viable for such an extensive number of data. A brief contrasting comparison of evaluation methods based on frequency analysis by means of fast Fourier transform and on correlation methods such as minimum quadratic difference is used to encompass the limits and accuracy of the ILIDS method for such applications. (paper)

  16. Accuracy of hiatal hernia detection with esophageal high-resolution manometry

    NARCIS (Netherlands)

    Weijenborg, P. W.; van Hoeij, F. B.; Smout, A. J. P. M.; Bredenoord, A. J.

    2015-01-01

    The diagnosis of a sliding hiatal hernia is classically made with endoscopy or barium esophagogram. Spatial separation of the lower esophageal sphincter (LES) and diaphragm, the hallmark of hiatal hernia, can also be observed on high-resolution manometry (HRM), but the diagnostic accuracy of this

  17. High-accuracy identification and bioinformatic analysis of in vivo protein phosphorylation sites in yeast

    DEFF Research Database (Denmark)

    Gnad, Florian; de Godoy, Lyris M F; Cox, Jürgen

    2009-01-01

    Protein phosphorylation is a fundamental regulatory mechanism that affects many cell signaling processes. Using high-accuracy MS and stable isotope labeling in cell culture-labeling, we provide a global view of the Saccharomyces cerevisiae phosphoproteome, containing 3620 phosphorylation sites ma...

  18. High accuracy positioning using carrier-phases with the opensource GPSTK software

    OpenAIRE

    Salazar Hernández, Dagoberto José; Hernández Pajares, Manuel; Juan Zornoza, José Miguel; Sanz Subirana, Jaume

    2008-01-01

    The objective of this work is to show how using a proper GNSS data management strategy, combined with the flexibility provided by the open source "GPS Toolkit" (GPSTk), it is possible to easily develop both simple code-based processing strategies as well as basic high accuracy carrier-phase positioning techniques like Precise Point Positioning (PPP

  19. Very high-accuracy calibration of radiation pattern and gain of a near-field probe

    DEFF Research Database (Denmark)

    Pivnenko, Sergey; Nielsen, Jeppe Majlund; Breinbjerg, Olav

    2014-01-01

    In this paper, very high-accuracy calibration of the radiation pattern and gain of a near-field probe is described. An open-ended waveguide near-field probe has been used in a recent measurement of the C-band Synthetic Aperture Radar (SAR) Antenna Subsystem for the Sentinel 1 mission of the Europ...

  20. From journal to headline: the accuracy of climate science news in Danish high quality newspapers

    DEFF Research Database (Denmark)

    Vestergård, Gunver Lystbæk

    2011-01-01

    analysis to examine the accuracy of Danish high quality newspapers in quoting scientific publications from 1997 to 2009. Out of 88 articles, 46 contained inaccuracies though the majority was found to be insignificant and random. The study concludes that Danish broadsheet newspapers are ‘moderately...

  1. Interferometric study of the small magellanic cloud

    International Nuclear Information System (INIS)

    Torres, G.; Carranza, G.J.

    1986-01-01

    interferometric observations of the general radial velocity field in the small magellanic cloud are being carried out. We present preliminary results in reasonable agreement with H I measurements. (author)

  2. Technics study on high accuracy crush dressing and sharpening of diamond grinding wheel

    Science.gov (United States)

    Jia, Yunhai; Lu, Xuejun; Li, Jiangang; Zhu, Lixin; Song, Yingjie

    2011-05-01

    Mechanical grinding of artificial diamond grinding wheel was traditional wheel dressing process. The rotate speed and infeed depth of tool wheel were main technics parameters. The suitable technics parameters of metals-bonded diamond grinding wheel and resin-bonded diamond grinding wheel high accuracy crush dressing were obtained by a mount of experiment in super-hard material wheel dressing grind machine and by analysis of grinding force. In the same time, the effect of machine sharpening and sprinkle granule sharpening was contrasted. These analyses and lots of experiments had extent instruction significance to artificial diamond grinding wheel accuracy crush dressing.

  3. High accuracy interface characterization of three phase material systems in three dimensions

    DEFF Research Database (Denmark)

    Jørgensen, Peter Stanley; Hansen, Karin Vels; Larsen, Rasmus

    2010-01-01

    Quantification of interface properties such as two phase boundary area and triple phase boundary length is important in the characterization ofmanymaterial microstructures, in particular for solid oxide fuel cell electrodes. Three-dimensional images of these microstructures can be obtained...... by tomography schemes such as focused ion beam serial sectioning or micro-computed tomography. We present a high accuracy method of calculating two phase surface areas and triple phase length of triple phase systems from subvoxel accuracy segmentations of constituent phases. The method performs a three phase...... polygonization of the interface boundaries which results in a non-manifold mesh of connected faces. We show how the triple phase boundaries can be extracted as connected curve loops without branches. The accuracy of the method is analyzed by calculations on geometrical primitives...

  4. Automated novel high-accuracy miniaturized positioning system for use in analytical instrumentation

    Science.gov (United States)

    Siomos, Konstadinos; Kaliakatsos, John; Apostolakis, Manolis; Lianakis, John; Duenow, Peter

    1996-01-01

    The development of three-dimensional automotive devices (micro-robots) for applications in analytical instrumentation, clinical chemical diagnostics and advanced laser optics, depends strongly on the ability of such a device: firstly to be positioned with high accuracy, reliability, and automatically, by means of user friendly interface techniques; secondly to be compact; and thirdly to operate under vacuum conditions, free of most of the problems connected with conventional micropositioners using stepping-motor gear techniques. The objective of this paper is to develop and construct a mechanically compact computer-based micropositioning system for coordinated motion in the X-Y-Z directions with: (1) a positioning accuracy of less than 1 micrometer, (the accuracy of the end-position of the system is controlled by a hard/software assembly using a self-constructed optical encoder); (2) a heat-free propulsion mechanism for vacuum operation; and (3) synchronized X-Y motion.

  5. Nanohertz gravitational wave searches with interferometric pulsar timing experiments.

    Science.gov (United States)

    Tinto, Massimo

    2011-05-13

    We estimate the sensitivity to nano-Hertz gravitational waves of pulsar timing experiments in which two highly stable millisecond pulsars are tracked simultaneously with two neighboring radio telescopes that are referenced to the same timekeeping subsystem (i.e., "the clock"). By taking the difference of the two time-of-arrival residual data streams we can exactly cancel the clock noise in the combined data set, thereby enhancing the sensitivity to gravitational waves. We estimate that, in the band (10(-9)-10(-8))  Hz, this "interferometric" pulsar timing technique can potentially improve the sensitivity to gravitational radiation by almost 2 orders of magnitude over that of single-telescopes. Interferometric pulsar timing experiments could be performed with neighboring pairs of antennas of the NASA's Deep Space Network and the forthcoming large arraying projects.

  6. Low-cost interferometric TDM technology for dynamic sensing applications

    Science.gov (United States)

    Bush, Jeff; Cekorich, Allen

    2004-12-01

    A low-cost design approach for Time Division Multiplexed (TDM) fiber-optic interferometric interrogation of multi-channel sensor arrays is presented. This paper describes the evolutionary design process of the subject design. First, the requisite elements of interferometric interrogation are defined for a single channel sensor. The concept is then extended to multi-channel sensor interrogation implementing a TDM multiplex scheme where "traditional" design elements are utilized. The cost of the traditional TDM interrogator is investigated and concluded to be too high for entry into many markets. A new design approach is presented which significantly reduces the cost for TDM interrogation. This new approach, in accordance with the cost objectives, shows promise to bring this technology to within the threshold of commercial acceptance for a wide range of distributed fiber sensing applications.

  7. High Accuracy Acoustic Relative Humidity Measurement inDuct Flow with Air

    Directory of Open Access Journals (Sweden)

    Cees van der Geld

    2010-08-01

    Full Text Available An acoustic relative humidity sensor for air-steam mixtures in duct flow is designed and tested. Theory, construction, calibration, considerations on dynamic response and results are presented. The measurement device is capable of measuring line averaged values of gas velocity, temperature and relative humidity (RH instantaneously, by applying two ultrasonic transducers and an array of four temperature sensors. Measurement ranges are: gas velocity of 0–12 m/s with an error of ±0.13 m/s, temperature 0–100 °C with an error of ±0.07 °C and relative humidity 0–100% with accuracy better than 2 % RH above 50 °C. Main advantage over conventional humidity sensors is the high sensitivity at high RH at temperatures exceeding 50 °C, with accuracy increasing with increasing temperature. The sensors are non-intrusive and resist highly humid environments.

  8. High accuracy digital aging monitor based on PLL-VCO circuit

    International Nuclear Information System (INIS)

    Zhang Yuejun; Jiang Zhidi; Wang Pengjun; Zhang Xuelong

    2015-01-01

    As the manufacturing process is scaled down to the nanoscale, the aging phenomenon significantly affects the reliability and lifetime of integrated circuits. Consequently, the precise measurement of digital CMOS aging is a key aspect of nanoscale aging tolerant circuit design. This paper proposes a high accuracy digital aging monitor using phase-locked loop and voltage-controlled oscillator (PLL-VCO) circuit. The proposed monitor eliminates the circuit self-aging effect for the characteristic of PLL, whose frequency has no relationship with circuit aging phenomenon. The PLL-VCO monitor is implemented in TSMC low power 65 nm CMOS technology, and its area occupies 303.28 × 298.94 μm 2 . After accelerating aging tests, the experimental results show that PLL-VCO monitor improves accuracy about high temperature by 2.4% and high voltage by 18.7%. (semiconductor integrated circuits)

  9. High accuracy acoustic relative humidity measurement in duct flow with air.

    Science.gov (United States)

    van Schaik, Wilhelm; Grooten, Mart; Wernaart, Twan; van der Geld, Cees

    2010-01-01

    An acoustic relative humidity sensor for air-steam mixtures in duct flow is designed and tested. Theory, construction, calibration, considerations on dynamic response and results are presented. The measurement device is capable of measuring line averaged values of gas velocity, temperature and relative humidity (RH) instantaneously, by applying two ultrasonic transducers and an array of four temperature sensors. Measurement ranges are: gas velocity of 0-12 m/s with an error of ± 0.13 m/s, temperature 0-100 °C with an error of ± 0.07 °C and relative humidity 0-100% with accuracy better than 2 % RH above 50 °C. Main advantage over conventional humidity sensors is the high sensitivity at high RH at temperatures exceeding 50 °C, with accuracy increasing with increasing temperature. The sensors are non-intrusive and resist highly humid environments.

  10. A proposal for limited criminal liability in high-accuracy endoscopic sinus surgery.

    Science.gov (United States)

    Voultsos, P; Casini, M; Ricci, G; Tambone, V; Midolo, E; Spagnolo, A G

    2017-02-01

    The aim of the present study is to propose legal reform limiting surgeons' criminal liability in high-accuracy and high-risk surgery such as endoscopic sinus surgery (ESS). The study includes a review of the medical literature, focusing on identifying and examining reasons why ESS carries a very high risk of serious complications related to inaccurate surgical manoeuvers and reviewing British and Italian legal theory and case-law on medical negligence, especially with regard to Italian Law 189/2012 (so called "Balduzzi" Law). It was found that serious complications due to inaccurate surgical manoeuvers may occur in ESS regardless of the skill, experience and prudence/diligence of the surgeon. Subjectivity should be essential to medical negligence, especially regarding high-accuracy surgery. Italian Law 189/2012 represents a good basis for the limitation of criminal liability resulting from inaccurate manoeuvres in high-accuracy surgery such as ESS. It is concluded that ESS surgeons should be relieved of criminal liability in cases of simple/ordinary negligence where guidelines have been observed. © Copyright by Società Italiana di Otorinolaringologia e Chirurgia Cervico-Facciale, Rome, Italy.

  11. Interferometric Imaging Directly with Closure Phases and Closure Amplitudes

    Science.gov (United States)

    Chael, Andrew A.; Johnson, Michael D.; Bouman, Katherine L.; Blackburn, Lindy L.; Akiyama, Kazunori; Narayan, Ramesh

    2018-04-01

    Interferometric imaging now achieves angular resolutions as fine as ∼10 μas, probing scales that are inaccessible to single telescopes. Traditional synthesis imaging methods require calibrated visibilities; however, interferometric calibration is challenging, especially at high frequencies. Nevertheless, most studies present only a single image of their data after a process of “self-calibration,” an iterative procedure where the initial image and calibration assumptions can significantly influence the final image. We present a method for efficient interferometric imaging directly using only closure amplitudes and closure phases, which are immune to station-based calibration errors. Closure-only imaging provides results that are as noncommittal as possible and allows for reconstructing an image independently from separate amplitude and phase self-calibration. While closure-only imaging eliminates some image information (e.g., the total image flux density and the image centroid), this information can be recovered through a small number of additional constraints. We demonstrate that closure-only imaging can produce high-fidelity results, even for sparse arrays such as the Event Horizon Telescope, and that the resulting images are independent of the level of systematic amplitude error. We apply closure imaging to VLBA and ALMA data and show that it is capable of matching or exceeding the performance of traditional self-calibration and CLEAN for these data sets.

  12. Gene masking - a technique to improve accuracy for cancer classification with high dimensionality in microarray data.

    Science.gov (United States)

    Saini, Harsh; Lal, Sunil Pranit; Naidu, Vimal Vikash; Pickering, Vincel Wince; Singh, Gurmeet; Tsunoda, Tatsuhiko; Sharma, Alok

    2016-12-05

    High dimensional feature space generally degrades classification in several applications. In this paper, we propose a strategy called gene masking, in which non-contributing dimensions are heuristically removed from the data to improve classification accuracy. Gene masking is implemented via a binary encoded genetic algorithm that can be integrated seamlessly with classifiers during the training phase of classification to perform feature selection. It can also be used to discriminate between features that contribute most to the classification, thereby, allowing researchers to isolate features that may have special significance. This technique was applied on publicly available datasets whereby it substantially reduced the number of features used for classification while maintaining high accuracies. The proposed technique can be extremely useful in feature selection as it heuristically removes non-contributing features to improve the performance of classifiers.

  13. High Accuracy Evaluation of the Finite Fourier Transform Using Sampled Data

    Science.gov (United States)

    Morelli, Eugene A.

    1997-01-01

    Many system identification and signal processing procedures can be done advantageously in the frequency domain. A required preliminary step for this approach is the transformation of sampled time domain data into the frequency domain. The analytical tool used for this transformation is the finite Fourier transform. Inaccuracy in the transformation can degrade system identification and signal processing results. This work presents a method for evaluating the finite Fourier transform using cubic interpolation of sampled time domain data for high accuracy, and the chirp Zeta-transform for arbitrary frequency resolution. The accuracy of the technique is demonstrated in example cases where the transformation can be evaluated analytically. Arbitrary frequency resolution is shown to be important for capturing details of the data in the frequency domain. The technique is demonstrated using flight test data from a longitudinal maneuver of the F-18 High Alpha Research Vehicle.

  14. High-Accuracy Spherical Near-Field Measurements for Satellite Antenna Testing

    DEFF Research Database (Denmark)

    Breinbjerg, Olav

    2017-01-01

    The spherical near-field antenna measurement technique is unique in combining several distinct advantages and it generally constitutes the most accurate technique for experimental characterization of radiation from antennas. From the outset in 1970, spherical near-field antenna measurements have...... matured into a well-established technique that is widely used for testing antennas for many wireless applications. In particular, for high-accuracy applications, such as remote sensing satellite missions in ESA's Earth Observation Programme with uncertainty requirements at the level of 0.05dB - 0.10d......B, the spherical near-field antenna measurement technique is generally superior. This paper addresses the means to achieving high measurement accuracy; these include the measurement technique per se, its implementation in terms of proper measurement procedures, the use of uncertainty estimates, as well as facility...

  15. A New Approach to High-accuracy Road Orthophoto Mapping Based on Wavelet Transform

    Directory of Open Access Journals (Sweden)

    Ming Yang

    2011-12-01

    Full Text Available Existing orthophoto map based on satellite photography and aerial photography is not precise enough for road marking. This paper proposes a new approach to high-accuracy orthophoto mapping. The approach uses inverse perspective transformation to process the image information and generates the orthophoto fragment. The offline interpolation algorithm is used to process the location information. It processes the dead reckoning and the EKF location information, and uses the result to transform the fragments to the global coordinate system. At last it uses wavelet transform to divides the image to two frequency bands and uses weighted median algorithm to deal with them separately. The result of experiment shows that the map produced with this method has high accuracy.

  16. Iterated unscented Kalman filter for phase unwrapping of interferometric fringes.

    Science.gov (United States)

    Xie, Xianming

    2016-08-22

    A fresh phase unwrapping algorithm based on iterated unscented Kalman filter is proposed to estimate unambiguous unwrapped phase of interferometric fringes. This method is the result of combining an iterated unscented Kalman filter with a robust phase gradient estimator based on amended matrix pencil model, and an efficient quality-guided strategy based on heap sort. The iterated unscented Kalman filter that is one of the most robust methods under the Bayesian theorem frame in non-linear signal processing so far, is applied to perform simultaneously noise suppression and phase unwrapping of interferometric fringes for the first time, which can simplify the complexity and the difficulty of pre-filtering procedure followed by phase unwrapping procedure, and even can remove the pre-filtering procedure. The robust phase gradient estimator is used to efficiently and accurately obtain phase gradient information from interferometric fringes, which is needed for the iterated unscented Kalman filtering phase unwrapping model. The efficient quality-guided strategy is able to ensure that the proposed method fast unwraps wrapped pixels along the path from the high-quality area to the low-quality area of wrapped phase images, which can greatly improve the efficiency of phase unwrapping. Results obtained from synthetic data and real data show that the proposed method can obtain better solutions with an acceptable time consumption, with respect to some of the most used algorithms.

  17. Identification and delineation of areas flood hazard using high accuracy of DEM data

    Science.gov (United States)

    Riadi, B.; Barus, B.; Widiatmaka; Yanuar, M. J. P.; Pramudya, B.

    2018-05-01

    Flood incidents that often occur in Karawang regency need to be mitigated. These expectations exist on technologies that can predict, anticipate and reduce disaster risks. Flood modeling techniques using Digital Elevation Model (DEM) data can be applied in mitigation activities. High accuracy DEM data used in modeling, will result in better flooding flood models. The result of high accuracy DEM data processing will yield information about surface morphology which can be used to identify indication of flood hazard area. The purpose of this study was to identify and describe flood hazard areas by identifying wetland areas using DEM data and Landsat-8 images. TerraSAR-X high-resolution data is used to detect wetlands from landscapes, while land cover is identified by Landsat image data. The Topography Wetness Index (TWI) method is used to detect and identify wetland areas with basic DEM data, while for land cover analysis using Tasseled Cap Transformation (TCT) method. The result of TWI modeling yields information about potential land of flood. Overlay TWI map with land cover map that produces information that in Karawang regency the most vulnerable areas occur flooding in rice fields. The spatial accuracy of the flood hazard area in this study was 87%.

  18. Accuracy of Estimating Highly Eccentric Binary Black Hole Parameters with Gravitational-wave Detections

    Science.gov (United States)

    Gondán, László; Kocsis, Bence; Raffai, Péter; Frei, Zsolt

    2018-03-01

    Mergers of stellar-mass black holes on highly eccentric orbits are among the targets for ground-based gravitational-wave detectors, including LIGO, VIRGO, and KAGRA. These sources may commonly form through gravitational-wave emission in high-velocity dispersion systems or through the secular Kozai–Lidov mechanism in triple systems. Gravitational waves carry information about the binaries’ orbital parameters and source location. Using the Fisher matrix technique, we determine the measurement accuracy with which the LIGO–VIRGO–KAGRA network could measure the source parameters of eccentric binaries using a matched filtering search of the repeated burst and eccentric inspiral phases of the waveform. We account for general relativistic precession and the evolution of the orbital eccentricity and frequency during the inspiral. We find that the signal-to-noise ratio and the parameter measurement accuracy may be significantly higher for eccentric sources than for circular sources. This increase is sensitive to the initial pericenter distance, the initial eccentricity, and the component masses. For instance, compared to a 30 {M}ȯ –30 {M}ȯ non-spinning circular binary, the chirp mass and sky-localization accuracy can improve by a factor of ∼129 (38) and ∼2 (11) for an initially highly eccentric binary assuming an initial pericenter distance of 20 M tot (10 M tot).

  19. A Smart High Accuracy Silicon Piezoresistive Pressure Sensor Temperature Compensation System

    Directory of Open Access Journals (Sweden)

    Guanwu Zhou

    2014-07-01

    Full Text Available Theoretical analysis in this paper indicates that the accuracy of a silicon piezoresistive pressure sensor is mainly affected by thermal drift, and varies nonlinearly with the temperature. Here, a smart temperature compensation system to reduce its effect on accuracy is proposed. Firstly, an effective conditioning circuit for signal processing and data acquisition is designed. The hardware to implement the system is fabricated. Then, a program is developed on LabVIEW which incorporates an extreme learning machine (ELM as the calibration algorithm for the pressure drift. The implementation of the algorithm was ported to a micro-control unit (MCU after calibration in the computer. Practical pressure measurement experiments are carried out to verify the system’s performance. The temperature compensation is solved in the interval from −40 to 85 °C. The compensated sensor is aimed at providing pressure measurement in oil-gas pipelines. Compared with other algorithms, ELM acquires higher accuracy and is more suitable for batch compensation because of its higher generalization and faster learning speed. The accuracy, linearity, zero temperature coefficient and sensitivity temperature coefficient of the tested sensor are 2.57% FS, 2.49% FS, 8.1 × 10−5/°C and 29.5 × 10−5/°C before compensation, and are improved to 0.13%FS, 0.15%FS, 1.17 × 10−5/°C and 2.1 × 10−5/°C respectively, after compensation. The experimental results demonstrate that the proposed system is valid for the temperature compensation and high accuracy requirement of the sensor.

  20. Optical System Error Analysis and Calibration Method of High-Accuracy Star Trackers

    Directory of Open Access Journals (Sweden)

    Zheng You

    2013-04-01

    Full Text Available The star tracker is a high-accuracy attitude measurement device widely used in spacecraft. Its performance depends largely on the precision of the optical system parameters. Therefore, the analysis of the optical system parameter errors and a precise calibration model are crucial to the accuracy of the star tracker. Research in this field is relatively lacking a systematic and universal analysis up to now. This paper proposes in detail an approach for the synthetic error analysis of the star tracker, without the complicated theoretical derivation. This approach can determine the error propagation relationship of the star tracker, and can build intuitively and systematically an error model. The analysis results can be used as a foundation and a guide for the optical design, calibration, and compensation of the star tracker. A calibration experiment is designed and conducted. Excellent calibration results are achieved based on the calibration model. To summarize, the error analysis approach and the calibration method are proved to be adequate and precise, and could provide an important guarantee for the design, manufacture, and measurement of high-accuracy star trackers.

  1. Optical system error analysis and calibration method of high-accuracy star trackers.

    Science.gov (United States)

    Sun, Ting; Xing, Fei; You, Zheng

    2013-04-08

    The star tracker is a high-accuracy attitude measurement device widely used in spacecraft. Its performance depends largely on the precision of the optical system parameters. Therefore, the analysis of the optical system parameter errors and a precise calibration model are crucial to the accuracy of the star tracker. Research in this field is relatively lacking a systematic and universal analysis up to now. This paper proposes in detail an approach for the synthetic error analysis of the star tracker, without the complicated theoretical derivation. This approach can determine the error propagation relationship of the star tracker, and can build intuitively and systematically an error model. The analysis results can be used as a foundation and a guide for the optical design, calibration, and compensation of the star tracker. A calibration experiment is designed and conducted. Excellent calibration results are achieved based on the calibration model. To summarize, the error analysis approach and the calibration method are proved to be adequate and precise, and could provide an important guarantee for the design, manufacture, and measurement of high-accuracy star trackers.

  2. Implementation of High Time Delay Accuracy of Ultrasonic Phased Array Based on Interpolation CIC Filter.

    Science.gov (United States)

    Liu, Peilu; Li, Xinghua; Li, Haopeng; Su, Zhikun; Zhang, Hongxu

    2017-10-12

    In order to improve the accuracy of ultrasonic phased array focusing time delay, analyzing the original interpolation Cascade-Integrator-Comb (CIC) filter, an 8× interpolation CIC filter parallel algorithm was proposed, so that interpolation and multichannel decomposition can simultaneously process. Moreover, we summarized the general formula of arbitrary multiple interpolation CIC filter parallel algorithm and established an ultrasonic phased array focusing time delay system based on 8× interpolation CIC filter parallel algorithm. Improving the algorithmic structure, 12.5% of addition and 29.2% of multiplication was reduced, meanwhile the speed of computation is still very fast. Considering the existing problems of the CIC filter, we compensated the CIC filter; the compensated CIC filter's pass band is flatter, the transition band becomes steep, and the stop band attenuation increases. Finally, we verified the feasibility of this algorithm on Field Programming Gate Array (FPGA). In the case of system clock is 125 MHz, after 8× interpolation filtering and decomposition, time delay accuracy of the defect echo becomes 1 ns. Simulation and experimental results both show that the algorithm we proposed has strong feasibility. Because of the fast calculation, small computational amount and high resolution, this algorithm is especially suitable for applications with high time delay accuracy and fast detection.

  3. Implementation of High Time Delay Accuracy of Ultrasonic Phased Array Based on Interpolation CIC Filter

    Directory of Open Access Journals (Sweden)

    Peilu Liu

    2017-10-01

    Full Text Available In order to improve the accuracy of ultrasonic phased array focusing time delay, analyzing the original interpolation Cascade-Integrator-Comb (CIC filter, an 8× interpolation CIC filter parallel algorithm was proposed, so that interpolation and multichannel decomposition can simultaneously process. Moreover, we summarized the general formula of arbitrary multiple interpolation CIC filter parallel algorithm and established an ultrasonic phased array focusing time delay system based on 8× interpolation CIC filter parallel algorithm. Improving the algorithmic structure, 12.5% of addition and 29.2% of multiplication was reduced, meanwhile the speed of computation is still very fast. Considering the existing problems of the CIC filter, we compensated the CIC filter; the compensated CIC filter’s pass band is flatter, the transition band becomes steep, and the stop band attenuation increases. Finally, we verified the feasibility of this algorithm on Field Programming Gate Array (FPGA. In the case of system clock is 125 MHz, after 8× interpolation filtering and decomposition, time delay accuracy of the defect echo becomes 1 ns. Simulation and experimental results both show that the algorithm we proposed has strong feasibility. Because of the fast calculation, small computational amount and high resolution, this algorithm is especially suitable for applications with high time delay accuracy and fast detection.

  4. High-accuracy determination of the neutron flux at n{sub T}OF

    Energy Technology Data Exchange (ETDEWEB)

    Barbagallo, M.; Colonna, N.; Mastromarco, M.; Meaze, M.; Tagliente, G.; Variale, V. [Sezione di Bari, INFN, Bari (Italy); Guerrero, C.; Andriamonje, S.; Boccone, V.; Brugger, M.; Calviani, M.; Cerutti, F.; Chin, M.; Ferrari, A.; Kadi, Y.; Losito, R.; Versaci, R.; Vlachoudis, V. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Tsinganis, A. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); National Technical University of Athens (NTUA), Athens (Greece); Tarrio, D.; Duran, I.; Leal-Cidoncha, E.; Paradela, C. [Universidade de Santiago de Compostela, Santiago (Spain); Altstadt, S.; Goebel, K.; Langer, C.; Reifarth, R.; Schmidt, S.; Weigand, M. [Johann-Wolfgang-Goethe Universitaet, Frankfurt (Germany); Andrzejewski, J.; Marganiec, J.; Perkowski, J. [Uniwersytet Lodzki, Lodz (Poland); Audouin, L.; Leong, L.S.; Tassan-Got, L. [Centre National de la Recherche Scientifique/IN2P3 - IPN, Orsay (France); Becares, V.; Cano-Ott, D.; Garcia, A.R.; Gonzalez-Romero, E.; Martinez, T.; Mendoza, E. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain); Becvar, F.; Krticka, M.; Kroll, J.; Valenta, S. [Charles University, Prague (Czech Republic); Belloni, F.; Fraval, K.; Gunsing, F.; Lampoudis, C.; Papaevangelou, T. [Commissariata l' Energie Atomique (CEA) Saclay - Irfu, Gif-sur-Yvette (France); Berthoumieux, E.; Chiaveri, E. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Commissariata l' Energie Atomique (CEA) Saclay - Irfu, Gif-sur-Yvette (France); Billowes, J.; Ware, T.; Wright, T. [University of Manchester, Manchester (United Kingdom); Bosnar, D.; Zugec, P. [University of Zagreb, Department of Physics, Faculty of Science, Zagreb (Croatia); Calvino, F.; Cortes, G.; Gomez-Hornillos, M.B.; Riego, A. [Universitat Politecnica de Catalunya, Barcelona (Spain); Carrapico, C.; Goncalves, I.F.; Sarmento, R.; Vaz, P. [Universidade Tecnica de Lisboa, Instituto Tecnologico e Nuclear, Instituto Superior Tecnico, Lisboa (Portugal); Cortes-Giraldo, M.A.; Praena, J.; Quesada, J.M.; Sabate-Gilarte, M. [Universidad de Sevilla, Sevilla (Spain); Diakaki, M.; Karadimos, D.; Kokkoris, M.; Vlastou, R. [National Technical University of Athens (NTUA), Athens (Greece); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L. [CSIC-Universidad de Valencia, Instituto de Fisica Corpuscular, Valencia (Spain); Dressler, R.; Kivel, N.; Schumann, D.; Steinegger, P. [Paul Scherrer Institut, Villigen PSI (Switzerland); Dzysiuk, N.; Mastinu, P.F. [Laboratori Nazionali di Legnaro, INFN, Rome (Italy); Eleftheriadis, C.; Manousos, A. [Aristotle University of Thessaloniki, Thessaloniki (Greece); Ganesan, S.; Gurusamy, P.; Saxena, A. [Bhabha Atomic Research Centre (BARC), Mumbai (IN); Griesmayer, E.; Jericha, E.; Leeb, H. [Technische Universitaet Wien, Atominstitut, Wien (AT); Hernandez-Prieto, A. [European Organization for Nuclear Research (CERN), Geneva (CH); Universitat Politecnica de Catalunya, Barcelona (ES); Jenkins, D.G.; Vermeulen, M.J. [University of York, Heslington, York (GB); Kaeppeler, F. [Institut fuer Kernphysik, Karlsruhe Institute of Technology, Campus Nord, Karlsruhe (DE); Koehler, P. [Oak Ridge National Laboratory (ORNL), Oak Ridge (US); Lederer, C. [Johann-Wolfgang-Goethe Universitaet, Frankfurt (DE); University of Vienna, Faculty of Physics, Vienna (AT); Massimi, C.; Mingrone, F.; Vannini, G. [Universita di Bologna (IT); INFN, Sezione di Bologna, Dipartimento di Fisica, Bologna (IT); Mengoni, A.; Ventura, A. [Agenzia nazionale per le nuove tecnologie, l' energia e lo sviluppo economico sostenibile (ENEA), Bologna (IT); Milazzo, P.M. [Sezione di Trieste, INFN, Trieste (IT); Mirea, M. [Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN HH, Bucharest - Magurele (RO); Mondalaers, W.; Plompen, A.; Schillebeeckx, P. [Institute for Reference Materials and Measurements, European Commission JRC, Geel (BE); Pavlik, A.; Wallner, A. [University of Vienna, Faculty of Physics, Vienna (AT); Rauscher, T. [University of Basel, Department of Physics and Astronomy, Basel (CH); Roman, F. [European Organization for Nuclear Research (CERN), Geneva (CH); Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN HH, Bucharest - Magurele (RO); Rubbia, C. [European Organization for Nuclear Research (CERN), Geneva (CH); Laboratori Nazionali del Gran Sasso dell' INFN, Assergi (AQ) (IT); Weiss, C. [European Organization for Nuclear Research (CERN), Geneva (CH); Johann-Wolfgang-Goethe Universitaet, Frankfurt (DE)

    2013-12-15

    The neutron flux of the n{sub T}OF facility at CERN was measured, after installation of the new spallation target, with four different systems based on three neutron-converting reactions, which represent accepted cross sections standards in different energy regions. A careful comparison and combination of the different measurements allowed us to reach an unprecedented accuracy on the energy dependence of the neutron flux in the very wide range (thermal to 1 GeV) that characterizes the n{sub T}OF neutron beam. This is a pre-requisite for the high accuracy of cross section measurements at n{sub T}OF. An unexpected anomaly in the neutron-induced fission cross section of {sup 235}U is observed in the energy region between 10 and 30keV, hinting at a possible overestimation of this important cross section, well above currently assigned uncertainties. (orig.)

  5. Fission product model for BWR analysis with improved accuracy in high burnup

    International Nuclear Information System (INIS)

    Ikehara, Tadashi; Yamamoto, Munenari; Ando, Yoshihira

    1998-01-01

    A new fission product (FP) chain model has been studied to be used in a BWR lattice calculation. In attempting to establish the model, two requirements, i.e. the accuracy in predicting burnup reactivity and the easiness in practical application, are simultaneously considered. The resultant FP model consists of 81 explicit FP nuclides and two lumped pseudo nuclides having the absorption cross sections independent of burnup history and fuel composition. For the verification, extensive numerical tests covering over a wide range of operational conditions and fuel compositions have been carried out. The results indicate that the estimated errors in burnup reactivity are within 0.1%Δk for exposures up to 100GWd/t. It is concluded that the present model can offer a high degree of accuracy for FP representation in BWR lattice calculation. (author)

  6. High Accuracy Attitude Control System Design for Satellite with Flexible Appendages

    Directory of Open Access Journals (Sweden)

    Wenya Zhou

    2014-01-01

    Full Text Available In order to realize the high accuracy attitude control of satellite with flexible appendages, attitude control system consisting of the controller and structural filter was designed. When the low order vibration frequency of flexible appendages is approximating the bandwidth of attitude control system, the vibration signal will enter the control system through measurement device to bring impact on the accuracy or even the stability. In order to reduce the impact of vibration of appendages on the attitude control system, the structural filter is designed in terms of rejecting the vibration of flexible appendages. Considering the potential problem of in-orbit frequency variation of the flexible appendages, the design method for the adaptive notch filter is proposed based on the in-orbit identification technology. Finally, the simulation results are given to demonstrate the feasibility and effectiveness of the proposed design techniques.

  7. High-accuracy numerical integration of charged particle motion – with application to ponderomotive force

    International Nuclear Information System (INIS)

    Furukawa, Masaru; Ohkawa, Yushiro; Matsuyama, Akinobu

    2016-01-01

    A high-accuracy numerical integration algorithm for a charged particle motion is developed. The algorithm is based on the Hamiltonian mechanics and the operator decomposition. The algorithm is made to be time-reversal symmetric, and its order of accuracy can be increased to any order by using a recurrence formula. One of the advantages is that it is an explicit method. An effective way to decompose the time evolution operator is examined; the Poisson tensor is decomposed and non-canonical variables are adopted. The algorithm is extended to a time dependent fields' case by introducing the extended phase space. Numerical tests showing the performance of the algorithm are presented. One is the pure cyclotron motion for a long time period, and the other is a charged particle motion in a rapidly oscillating field. (author)

  8. High-accuracy defect sizing for CRDM penetration adapters using the ultrasonic TOFD technique

    International Nuclear Information System (INIS)

    Atkinson, I.

    1995-01-01

    Ultrasonic time-of-flight diffraction (TOFD) is the preferred technique for critical sizing of throughwall orientated defects in a wide range of components, primarily because it is intrinsically more accurate than amplitude-based techniques. For the same reason, TOFD is the preferred technique for sizing the cracks in control rod drive mechanism (CRDM) penetration adapters, which have been the subject of much recent attention. Once the considerable problem of restricted access for the UT probes has been overcome, this inspection lends itself to very high accuracy defect sizing using TOFD. In qualification trials under industrial conditions, depth sizing to an accuracy of ≤ 0.5 mm has been routinely achieved throughout the full wall thickness (16 mm) of the penetration adapters, using only a single probe pair and without recourse to signal processing. (author)

  9. High accuracy of family history of melanoma in Danish melanoma cases

    DEFF Research Database (Denmark)

    Wadt, Karin A W; Drzewiecki, Krzysztof T; Gerdes, Anne-Marie

    2015-01-01

    The incidence of melanoma in Denmark has immensely increased over the last 10 years making Denmark a high risk country for melanoma. In the last two decades multiple public campaigns have sought to increase the awareness of melanoma. Family history of melanoma is a known major risk factor...... but previous studies have shown that self-reported family history of melanoma is highly inaccurate. These studies are 15 years old and we wanted to examine if a higher awareness of melanoma has increased the accuracy of self-reported family history of melanoma. We examined the family history of 181 melanoma...

  10. Automation, Operation, and Data Analysis in the Cryogenic, High Accuracy, Refraction Measuring System (CHARMS)

    Science.gov (United States)

    Frey, Bradley J.; Leviton, Douglas B.

    2005-01-01

    The Cryogenic High Accuracy Refraction Measuring System (CHARMS) at NASA's Goddard Space Flight Center has been enhanced in a number of ways in the last year to allow the system to accurately collect refracted beam deviation readings automatically over a range of temperatures from 15 K to well beyond room temperature with high sampling density in both wavelength and temperature. The engineering details which make this possible are presented. The methods by which the most accurate angular measurements are made and the corresponding data reduction methods used to reduce thousands of observed angles to a handful of refractive index values are also discussed.

  11. Satellite SAR interferometric techniques applied to emergency mapping

    Science.gov (United States)

    Stefanova Vassileva, Magdalena; Riccardi, Paolo; Lecci, Daniele; Giulio Tonolo, Fabio; Boccardo Boccardo, Piero; Chiesa, Giuliana; Angeluccetti, Irene

    2017-04-01

    This paper aim to investigate the capabilities of the currently available SAR interferometric algorithms in the field of emergency mapping. Several tests have been performed exploiting the Copernicus Sentinel-1 data using the COTS software ENVI/SARscape 5.3. Emergency Mapping can be defined as "creation of maps, geo-information products and spatial analyses dedicated to providing situational awareness emergency management and immediate crisis information for response by means of extraction of reference (pre-event) and crisis (post-event) geographic information/data from satellite or aerial imagery". The conventional differential SAR interferometric technique (DInSAR) and the two currently available multi-temporal SAR interferometric approaches, i.e. Permanent Scatterer Interferometry (PSI) and Small BAseline Subset (SBAS), have been applied to provide crisis information useful for the emergency management activities. Depending on the considered Emergency Management phase, it may be distinguished between rapid mapping, i.e. fast provision of geospatial data regarding the area affected for the immediate emergency response, and monitoring mapping, i.e. detection of phenomena for risk prevention and mitigation activities. In order to evaluate the potential and limitations of the aforementioned SAR interferometric approaches for the specific rapid and monitoring mapping application, five main factors have been taken into account: crisis information extracted, input data required, processing time and expected accuracy. The results highlight that DInSAR has the capacity to delineate areas affected by large and sudden deformations and fulfills most of the immediate response requirements. The main limiting factor of interferometry is the availability of suitable SAR acquisition immediately after the event (e.g. Sentinel-1 mission characterized by 6-day revisiting time may not always satisfy the immediate emergency request). PSI and SBAS techniques are suitable to produce

  12. Applications of interferometrically derived terrain slopes: Normalization of SAR backscatter and the interferometric correlation coefficient

    Science.gov (United States)

    Werner, Charles L.; Wegmueller, Urs; Small, David L.; Rosen, Paul A.

    1994-01-01

    Terrain slopes, which can be measured with Synthetic Aperture Radar (SAR) interferometry either from a height map or from the interferometric phase gradient, were used to calculate the local incidence angle and the correct pixel area. Both are required for correct thematic interpretation of SAR data. The interferometric correlation depends on the pixel area projected on a plane perpendicular to the look vector and requires correction for slope effects. Methods for normalization of the backscatter and interferometric correlation for ERS-1 SAR are presented.

  13. High-Accuracy Elevation Data at Large Scales from Airborne Single-Pass SAR Interferometry

    Directory of Open Access Journals (Sweden)

    Guy Jean-Pierre Schumann

    2016-01-01

    Full Text Available Digital elevation models (DEMs are essential data sets for disaster risk management and humanitarian relief services as well as many environmental process models. At present, on the hand, globally available DEMs only meet the basic requirements and for many services and modeling studies are not of high enough spatial resolution and lack accuracy in the vertical. On the other hand, LiDAR-DEMs are of very high spatial resolution and great vertical accuracy but acquisition operations can be very costly for spatial scales larger than a couple of hundred square km and also have severe limitations in wetland areas and under cloudy and rainy conditions. The ideal situation would thus be to have a DEM technology that allows larger spatial coverage than LiDAR but without compromising resolution and vertical accuracy and still performing under some adverse weather conditions and at a reasonable cost. In this paper, we present a novel single pass In-SAR technology for airborne vehicles that is cost-effective and can generate DEMs with a vertical error of around 0.3 m for an average spatial resolution of 3 m. To demonstrate this capability, we compare a sample single-pass In-SAR Ka-band DEM of the California Central Valley from the NASA/JPL airborne GLISTIN-A to a high-resolution LiDAR DEM. We also perform a simple sensitivity analysis to floodplain inundation. Based on the findings of our analysis, we argue that this type of technology can and should be used to replace large regions of globally available lower resolution DEMs, particularly in coastal, delta and floodplain areas where a high number of assets, habitats and lives are at risk from natural disasters. We conclude with a discussion on requirements, advantages and caveats in terms of instrument and data processing.

  14. On The Generation of Interferometric Colors in High Purity and Technical Grade Aluminum: An Alternative Green Process for Metal Finishing Industry

    International Nuclear Information System (INIS)

    Chen, Yuting; Santos, Abel; Ho, Daena; Wang, Ye; Kumeria, Tushar; Li, Junsheng; Wang, Changhai; Losic, Dusan

    2015-01-01

    Graphical abstract: Toward green processes in metal finishing industry by rationally designed electrochemical anodization. Biomimetic photonic films based on nanoporous anodic alumina produced in high purity and technical grade aluminum foils display vivid colors that can be precisely tuned across the visible spectrum. The presented method is a solid rationale aimed toward green processes for metal finishing industry. - Highlights: • Environmentally friendly approach to color aluminum through biomimetic photonic films. • Nanoporous anodic alumina distributed Bragg Reflectors (NAA-DBRs). • Rationally designed galvanostatic pulse anodization approach. • Macroscopic and microscopic differences in high purity and technical grade aluminum. • Substitute method for conventional coloring processes in metal finishing industry. - Abstract: Metal finishing industry is one of the leading pollutants worldwide and green approaches are urgently needed in order to address health and environmental issues associated with this industrial activity. Herein, we present an environmentally friendly approach aimed to overcome some of these issues by coloring aluminum through biomimetic photonic films based on nanoporous anodic alumina distributed Bragg Reflectors (NAA-DBRs). Our study aims to compare the macroscopic and microscopic differences between the resulting photonic films produced in high purity and technical grade aluminum in terms of color features, appearance, electrochemical behavior and internal nanoporous structure in order to establish a solid rationale toward optimal fabrication processes that can be readily incorporated into industrial methodologies. The obtained results reveal that our approach, based on a rational galvanostatic pulse anodization approach, makes it possible to precisely generate a complete palette of colors in both types of aluminum substrates. As a result of its versatility, this method could become a promising alternative to substitute

  15. Accuracy of cell calculation methods used for analysis of high conversion light water reactor lattice

    International Nuclear Information System (INIS)

    Jeong, Chang-Joon; Okumura, Keisuke; Ishiguro, Yukio; Tanaka, Ken-ichi

    1990-01-01

    Validation tests were made for the accuracy of cell calculation methods used in analyses of tight lattices of a mixed-oxide (MOX) fuel core in a high conversion light water reactor (HCLWR). A series of cell calculations was carried out for the lattices referred from an international HCLWR benchmark comparison, with emphasis placed on the resonance calculation methods; the NR, IR approximations, the collision probability method with ultra-fine energy group. Verification was also performed for the geometrical modelling; a hexagonal/cylindrical cell, and the boundary condition; mirror/white reflection. In the calculations, important reactor physics parameters, such as the neutron multiplication factor, the conversion ratio and the void coefficient, were evaluated using the above methods for various HCLWR lattices with different moderator to fuel volume ratios, fuel materials and fissile plutonium enrichments. The calculated results were compared with each other, and the accuracy and applicability of each method were clarified by comparison with continuous energy Monte Carlo calculations. It was verified that the accuracy of the IR approximation became worse when the neutron spectrum became harder. It was also concluded that the cylindrical cell model with the white boundary condition was not so suitable for MOX fuelled lattices, as for UO 2 fuelled lattices. (author)

  16. Accuracy of High-Resolution Ultrasonography in the Detection of Extensor Tendon Lacerations.

    Science.gov (United States)

    Dezfuli, Bobby; Taljanovic, Mihra S; Melville, David M; Krupinski, Elizabeth A; Sheppard, Joseph E

    2016-02-01

    Lacerations to the extensor mechanism are usually diagnosed clinically. Ultrasound (US) has been a growing diagnostic tool for tendon injuries since the 1990s. To date, there has been no publication establishing the accuracy and reliability of US in the evaluation of extensor mechanism lacerations in the hand. The purpose of this study is to determine the accuracy of US to detect extensor tendon injuries in the hand. Sixteen fingers and 4 thumbs in 4 fresh-frozen and thawed cadaveric hands were used. Sixty-eight 0.5-cm transverse skin lacerations were created. Twenty-seven extensor tendons were sharply transected. The remaining skin lacerations were used as sham dissection controls. One US technologist and one fellowship-trained musculoskeletal radiologist performed real-time dynamic US studies in and out of water bath. A second fellowship trained musculoskeletal radiologist subsequently reviewed the static US images. Dynamic and static US interpretation accuracy was assessed using dissection as "truth." All 27 extensor tendon lacerations and controls were identified correctly with dynamic imaging as either injury models that had a transected extensor tendon or sham controls with intact extensor tendons (sensitivity = 100%, specificity = 100%, positive predictive value = 1.0; all significantly greater than chance). Static imaging had a sensitivity of 85%, specificity of 89%, and accuracy of 88% (all significantly greater than chance). The results of the dynamic real time versus static US imaging were clearly different but did not reach statistical significance. Diagnostic US is a very accurate noninvasive study that can identify extensor mechanism injuries. Clinically suspected cases of acute extensor tendon injury scanned by high-frequency US can aid and/or confirm the diagnosis, with dynamic imaging providing added value compared to static. Ultrasonography, to aid in the diagnosis of extensor mechanism lacerations, can be successfully used in a reliable and

  17. Accuracy assessment of high frequency 3D ultrasound for digital impression-taking of prepared teeth

    Science.gov (United States)

    Heger, Stefan; Vollborn, Thorsten; Tinschert, Joachim; Wolfart, Stefan; Radermacher, Klaus

    2013-03-01

    Silicone based impression-taking of prepared teeth followed by plaster casting is well-established but potentially less reliable, error-prone and inefficient, particularly in combination with emerging techniques like computer aided design and manufacturing (CAD/CAM) of dental prosthesis. Intra-oral optical scanners for digital impression-taking have been introduced but until now some drawbacks still exist. Because optical waves can hardly penetrate liquids or soft-tissues, sub-gingival preparations still need to be uncovered invasively prior to scanning. High frequency ultrasound (HFUS) based micro-scanning has been recently investigated as an alternative to optical intra-oral scanning. Ultrasound is less sensitive against oral fluids and in principal able to penetrate gingiva without invasively exposing of sub-gingival preparations. Nevertheless, spatial resolution as well as digitization accuracy of an ultrasound based micro-scanning system remains a critical parameter because the ultrasound wavelength in water-like media such as gingiva is typically smaller than that of optical waves. In this contribution, the in-vitro accuracy of ultrasound based micro-scanning for tooth geometry reconstruction is being investigated and compared to its extra-oral optical counterpart. In order to increase the spatial resolution of the system, 2nd harmonic frequencies from a mechanically driven focused single element transducer were separated and corresponding 3D surface models were calculated for both fundamentals and 2nd harmonics. Measurements on phantoms, model teeth and human teeth were carried out for evaluation of spatial resolution and surface detection accuracy. Comparison of optical and ultrasound digital impression taking indicate that, in terms of accuracy, ultrasound based tooth digitization can be an alternative for optical impression-taking.

  18. Technical accuracy of a neuronavigation system measured with a high-precision mechanical micromanipulator.

    Science.gov (United States)

    Kaus, M; Steinmeier, R; Sporer, T; Ganslandt, O; Fahlbusch, R

    1997-12-01

    This study was designed to determine and evaluate the different system-inherent sources of erroneous target localization of a light-emitting diode (LED)-based neuronavigation system (StealthStation, Stealth Technologies, Boulder, CO). The localization accuracy was estimated by applying a high-precision mechanical micromanipulator to move and exactly locate (+/- 0.1 micron) the pointer at multiple positions in the physical three-dimensional space. The localization error was evaluated by calculating the spatial distance between the (known) LED positions and the LED coordinates measured by the neuronavigator. The results are based on a study of approximately 280,000 independent coordinate measurements. The maximum localization error detected was 0.55 +/- 0.29 mm, with the z direction (distance to the camera array) being the most erroneous coordinate. Minimum localization error was found at a distance of 1400 mm from the central camera (optimal measurement position). Additional error due to 1) mechanical vibrations of the camera tripod (+/- 0.15 mm) and the reference frame (+/- 0.08 mm) and 2) extrapolation of the pointer tip position from the LED coordinates of at least +/- 0.12 mm were detected, leading to a total technical error of 0.55 +/- 0.64 mm. Based on this technical accuracy analysis, a set of handling recommendations is proposed, leading to an improved localization accuracy. The localization error could be reduced by 0.3 +/- 0.15 mm by correct camera positioning (1400 mm distance) plus 0.15 mm by vibration-eliminating fixation of the camera. Correct handling of the probe during the operation may improve the accuracy by up to 0.1 mm.

  19. Time-delay interferometric ranging for space-borne gravitational-wave detectors

    International Nuclear Information System (INIS)

    Tinto, Massimo; Vallisneri, Michele; Armstrong, J.W.

    2005-01-01

    Space-borne interferometric gravitational-wave detectors, sensitive in the low-frequency (mHz) band, will fly in the next decade. In these detectors, the spacecraft-to-spacecraft light-travel times will necessarily be unequal and time varying, and (because of aberration) will have different values on up- and down-links. In such unequal-armlength interferometers, laser-phase noise will be canceled by taking linear combinations of the laser-phase observables measured between pairs of spacecraft, appropriately time shifted by the light propagation times along the corresponding arms. This procedure, known as time-delay interferometry (TDI), requires an accurate knowledge of the light-time delays as functions of time. Here we propose a high-accuracy technique to estimate these time delays, and we study its use in the context of the Laser Interferometer Space Antenna (LISA) mission. We refer to this ranging technique, which relies on the TDI combinations themselves, as time-delay interferometric ranging (TDIR). For every TDI combination, we show that, by minimizing the rms power in that combination (averaged over integration times ∼10 4 s) with respect to the time-delay parameters, we obtain estimates of the time delays accurate enough to cancel laser noise to a level well below the secondary noises. Thus TDIR allows the implementation of TDI without the use of dedicated interspacecraft ranging systems, with a potential simplification of the LISA design. In this paper we define the TDIR procedure formally, and we characterize its expected performance via simulations with the Synthetic LISA software package

  20. A method of noise reduction in heterodyne interferometric vibration metrology by combining auto-correlation analysis and spectral filtering

    Science.gov (United States)

    Hao, Hongliang; Xiao, Wen; Chen, Zonghui; Ma, Lan; Pan, Feng

    2018-01-01

    Heterodyne interferometric vibration metrology is a useful technique for dynamic displacement and velocity measurement as it can provide a synchronous full-field output signal. With the advent of cost effective, high-speed real-time signal processing systems and software, processing of the complex signals encountered in interferometry has become more feasible. However, due to the coherent nature of the laser sources, the sequence of heterodyne interferogram are corrupted by a mixture of coherent speckle and incoherent additive noise, which can severely degrade the accuracy of the demodulated signal and the optical display. In this paper, a new heterodyne interferometric demodulation method by combining auto-correlation analysis and spectral filtering is described leading to an expression for the dynamic displacement and velocity of the object under test that is significantly more accurate in both the amplitude and frequency of the vibrating waveform. We present a mathematical model of the signals obtained from interferograms that contain both vibration information of the measured objects and the noise. A simulation of the signal demodulation process is presented and used to investigate the noise from the system and external factors. The experimental results show excellent agreement with measurements from a commercial Laser Doppler Velocimetry (LDV).

  1. Broadband EIT borehole measurements with high phase accuracy using numerical corrections of electromagnetic coupling effects

    International Nuclear Information System (INIS)

    Zhao, Y; Zimmermann, E; Wolters, B; Van Waasen, S; Huisman, J A; Treichel, A; Kemna, A

    2013-01-01

    Electrical impedance tomography (EIT) is gaining importance in the field of geophysics and there is increasing interest for accurate borehole EIT measurements in a broad frequency range (mHz to kHz) in order to study subsurface properties. To characterize weakly polarizable soils and sediments with EIT, high phase accuracy is required. Typically, long electrode cables are used for borehole measurements. However, this may lead to undesired electromagnetic coupling effects associated with the inductive coupling between the double wire pairs for current injection and potential measurement and the capacitive coupling between the electrically conductive shield of the cable and the electrically conductive environment surrounding the electrode cables. Depending on the electrical properties of the subsurface and the measured transfer impedances, both coupling effects can cause large phase errors that have typically limited the frequency bandwidth of field EIT measurements to the mHz to Hz range. The aim of this paper is to develop numerical corrections for these phase errors. To this end, the inductive coupling effect was modeled using electronic circuit models, and the capacitive coupling effect was modeled by integrating discrete capacitances in the electrical forward model describing the EIT measurement process. The correction methods were successfully verified with measurements under controlled conditions in a water-filled rain barrel, where a high phase accuracy of 0.8 mrad in the frequency range up to 10 kHz was achieved. The corrections were also applied to field EIT measurements made using a 25 m long EIT borehole chain with eight electrodes and an electrode separation of 1 m. The results of a 1D inversion of these measurements showed that the correction methods increased the measurement accuracy considerably. It was concluded that the proposed correction methods enlarge the bandwidth of the field EIT measurement system, and that accurate EIT measurements can now

  2. An angle encoder for super-high resolution and super-high accuracy using SelfA

    Science.gov (United States)

    Watanabe, Tsukasa; Kon, Masahito; Nabeshima, Nobuo; Taniguchi, Kayoko

    2014-06-01

    Angular measurement technology at high resolution for applications such as in hard disk drive manufacturing machines, precision measurement equipment and aspherical process machines requires a rotary encoder with high accuracy, high resolution and high response speed. However, a rotary encoder has angular deviation factors during operation due to scale error or installation error. It has been assumed to be impossible to achieve accuracy below 0.1″ in angular measurement or control after the installation onto the rotating axis. Self-calibration (Lu and Trumper 2007 CIRP Ann. 56 499; Kim et al 2011 Proc. MacroScale; Probst 2008 Meas. Sci. Technol. 19 015101; Probst et al Meas. Sci. Technol. 9 1059; Tadashi and Makoto 1993 J. Robot. Mechatronics 5 448; Ralf et al 2006 Meas. Sci. Technol. 17 2811) and cross-calibration (Probst et al 1998 Meas. Sci. Technol. 9 1059; Just et al 2009 Precis. Eng. 33 530; Burnashev 2013 Quantum Electron. 43 130) technologies for a rotary encoder have been actively discussed on the basis of the principle of circular closure. This discussion prompted the development of rotary tables which achieve reliable and high accuracy angular verification. We apply these technologies for the development of a rotary encoder not only to meet the requirement of super-high accuracy but also to meet that of super-high resolution. This paper presents the development of an encoder with 221 = 2097 152 resolutions per rotation (360°), that is, corresponding to a 0.62″ signal period, achieved by the combination of a laser rotary encoder supplied by Magnescale Co., Ltd and a self-calibratable encoder (SelfA) supplied by The National Institute of Advanced Industrial Science & Technology (AIST). In addition, this paper introduces the development of a rotary encoder to guarantee ±0.03″ accuracy at any point of the interpolated signal, with respect to the encoder at the minimum resolution of 233, that is, corresponding to a 0.0015″ signal period after

  3. An angle encoder for super-high resolution and super-high accuracy using SelfA

    International Nuclear Information System (INIS)

    Watanabe, Tsukasa; Kon, Masahito; Nabeshima, Nobuo; Taniguchi, Kayoko

    2014-01-01

    Angular measurement technology at high resolution for applications such as in hard disk drive manufacturing machines, precision measurement equipment and aspherical process machines requires a rotary encoder with high accuracy, high resolution and high response speed. However, a rotary encoder has angular deviation factors during operation due to scale error or installation error. It has been assumed to be impossible to achieve accuracy below 0.1″ in angular measurement or control after the installation onto the rotating axis. Self-calibration (Lu and Trumper 2007 CIRP Ann. 56 499; Kim et al 2011 Proc. MacroScale; Probst 2008 Meas. Sci. Technol. 19 015101; Probst et al Meas. Sci. Technol. 9 1059; Tadashi and Makoto 1993 J. Robot. Mechatronics 5 448; Ralf et al 2006 Meas. Sci. Technol. 17 2811) and cross-calibration (Probst et al 1998 Meas. Sci. Technol. 9 1059; Just et al 2009 Precis. Eng. 33 530; Burnashev 2013 Quantum Electron. 43 130) technologies for a rotary encoder have been actively discussed on the basis of the principle of circular closure. This discussion prompted the development of rotary tables which achieve reliable and high accuracy angular verification. We apply these technologies for the development of a rotary encoder not only to meet the requirement of super-high accuracy but also to meet that of super-high resolution. This paper presents the development of an encoder with 2 21 = 2097 152 resolutions per rotation (360°), that is, corresponding to a 0.62″ signal period, achieved by the combination of a laser rotary encoder supplied by Magnescale Co., Ltd and a self-calibratable encoder (SelfA) supplied by The National Institute of Advanced Industrial Science and Technology (AIST). In addition, this paper introduces the development of a rotary encoder to guarantee ±0.03″ accuracy at any point of the interpolated signal, with respect to the encoder at the minimum resolution of 2 33 , that is, corresponding to a 0.0015″ signal period

  4. Ultra-high accuracy optical testing: creating diffraction-limitedshort-wavelength optical systems

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Kenneth A.; Naulleau, Patrick P.; Rekawa, Senajith B.; Denham, Paul E.; Liddle, J. Alexander; Gullikson, Eric M.; Jackson, KeithH.; Anderson, Erik H.; Taylor, John S.; Sommargren, Gary E.; Chapman,Henry N.; Phillion, Donald W.; Johnson, Michael; Barty, Anton; Soufli,Regina; Spiller, Eberhard A.; Walton, Christopher C.; Bajt, Sasa

    2005-08-03

    Since 1993, research in the fabrication of extreme ultraviolet (EUV) optical imaging systems, conducted at Lawrence Berkeley National Laboratory (LBNL) and Lawrence Livermore National Laboratory (LLNL), has produced the highest resolution optical systems ever made. We have pioneered the development of ultra-high-accuracy optical testing and alignment methods, working at extreme ultraviolet wavelengths, and pushing wavefront-measuring interferometry into the 2-20-nm wavelength range (60-600 eV). These coherent measurement techniques, including lateral shearing interferometry and phase-shifting point-diffraction interferometry (PS/PDI) have achieved RMS wavefront measurement accuracies of 0.5-1-{angstrom} and better for primary aberration terms, enabling the creation of diffraction-limited EUV optics. The measurement accuracy is established using careful null-testing procedures, and has been verified repeatedly through high-resolution imaging. We believe these methods are broadly applicable to the advancement of short-wavelength optical systems including space telescopes, microscope objectives, projection lenses, synchrotron beamline optics, diffractive and holographic optics, and more. Measurements have been performed on a tunable undulator beamline at LBNL's Advanced Light Source (ALS), optimized for high coherent flux; although many of these techniques should be adaptable to alternative ultraviolet, EUV, and soft x-ray light sources. To date, we have measured nine prototype all-reflective EUV optical systems with NA values between 0.08 and 0.30 (f/6.25 to f/1.67). These projection-imaging lenses were created for the semiconductor industry's advanced research in EUV photolithography, a technology slated for introduction in 2009-13. This paper reviews the methods used and our program's accomplishments to date.

  5. Ultra-high accuracy optical testing: creating diffraction-limited short-wavelength optical systems

    International Nuclear Information System (INIS)

    Goldberg, Kenneth A.; Naulleau, Patrick P.; Rekawa, Senajith B.; Denham, Paul E.; Liddle, J. Alexander; Gullikson, Eric M.; Jackson, KeithH.; Anderson, Erik H.; Taylor, John S.; Sommargren, Gary E.; Chapman, Henry N.; Phillion, Donald W.; Johnson, Michael; Barty, Anton; Soufli, Regina; Spiller, Eberhard A.; Walton, Christopher C.; Bajt, Sasa

    2005-01-01

    Since 1993, research in the fabrication of extreme ultraviolet (EUV) optical imaging systems, conducted at Lawrence Berkeley National Laboratory (LBNL) and Lawrence Livermore National Laboratory (LLNL), has produced the highest resolution optical systems ever made. We have pioneered the development of ultra-high-accuracy optical testing and alignment methods, working at extreme ultraviolet wavelengths, and pushing wavefront-measuring interferometry into the 2-20-nm wavelength range (60-600 eV). These coherent measurement techniques, including lateral shearing interferometry and phase-shifting point-diffraction interferometry (PS/PDI) have achieved RMS wavefront measurement accuracies of 0.5-1-(angstrom) and better for primary aberration terms, enabling the creation of diffraction-limited EUV optics. The measurement accuracy is established using careful null-testing procedures, and has been verified repeatedly through high-resolution imaging. We believe these methods are broadly applicable to the advancement of short-wavelength optical systems including space telescopes, microscope objectives, projection lenses, synchrotron beamline optics, diffractive and holographic optics, and more. Measurements have been performed on a tunable undulator beamline at LBNL's Advanced Light Source (ALS), optimized for high coherent flux; although many of these techniques should be adaptable to alternative ultraviolet, EUV, and soft x-ray light sources. To date, we have measured nine prototype all-reflective EUV optical systems with NA values between 0.08 and 0.30 (f/6.25 to f/1.67). These projection-imaging lenses were created for the semiconductor industry's advanced research in EUV photolithography, a technology slated for introduction in 2009-13. This paper reviews the methods used and our program's accomplishments to date

  6. Design of a high-magnification and low-aberration compact catadioptric telescope for the Advanced Virgo gravitational-wave interferometric detector

    International Nuclear Information System (INIS)

    Buy, C; Barsuglia, M; Tacca, M; Genin, E; Gouaty, R

    2017-01-01

    Advanced Virgo is a major upgrade of the Virgo gravitational-wave detector, aiming to increase its sensitivity by an order of magnitude. Among the main modifications of the instrument, the size of the laser beam inside the central area has been roughly doubled. Consequently, the input/output optics systems have been re-designed. Due to the overall Advanced Virgo optical scheme, high-magnification and compact telescopes are needed. These telescopes also have to fulfill stringent requirements in terms of aberrations, separation of secondary beams and scattered light. In this paper we describe the design of the Advanced Virgo telescopes and their estimated performances in terms of tuning capability and optical properties. (paper)

  7. Study of isospin correlation in high energy S + Pb and Pb + Pb interactions with a magnetic-interferometric-emulsion-chamber. Final report

    International Nuclear Information System (INIS)

    Takahashi, Yoshiyuki

    1997-01-01

    This report describes the research results of the study of high energy heavy-ion interactions and multi-cluster correlations at the University of Alabama in Huntsville (UAH). This study has been performed as the CERN experiments, EMU05, EMU09 and EMU16, and a part of the RHIC PHENIX and its MVD Collaboration work. Physics objectives and methods are described in chapters 1, 2, 3 and Appendices A1 and A2. The experimental set-up, measurements, an the data analyses at UAH are described in chapters 4 through 10 and Appendices. The UAH research was a quest for high density state of nuclear matter, in terms of finding analysis methods of multi-isospin correlations. The present work emphasized a study of the fluctuation of the particle density, discriminating the isospin for exploring the Disoriented Chiral Condensate (DCC). The analysis methods developed are: (1) Chi-square density test; (2) Run-test; (3) G-test; (4) Fourier analysis; and (5) Lomb's Periodogram. The application of these methods for central collision events in 2,000 GeV/n S + Pb and 167 GeV/n Pb + Pb produced interesting DCC correlations for a few events. However, further investigation of fluctuations with Monte Carlo method guided them to understand various hidden degree of freedoms in such analyses. The results of the analysis of the experimental data in comparison with the Monte Carlo data did not support the DCC process as compelling. The developed methods evolved for a plan to investigate the DCC in the PHENIX. The study has obtained several mathematical analysis methods from the CERN EMU05/16 experiments for a possible use in RHIC experiments

  8. The use of high accuracy NAA for the certification of NIST botanical standard reference materials

    International Nuclear Information System (INIS)

    Becker, D.A.; Greenberg, R.R.; Stone, S.F.

    1992-01-01

    Neutron activation analysis is one of many analytical techniques used at the National Institute of Standards and Technology (NIST) for the certification of NIST Standard Reference Materials (SRMs). NAA competes favorably with all other techniques because of it's unique capabilities for high accuracy even at very low concentrations for many elements. In this paper, instrumental and radiochemical NAA results are described for 25 elements in two new NIST SRMs, SRM 1515 (Apple Leaves) and SRM 1547 (Peach Leaves), and are compared to the certified values for 19 elements in these two new botanical reference materials. (author) 7 refs.; 4 tabs

  9. High-accuracy critical exponents for O(N) hierarchical 3D sigma models

    International Nuclear Information System (INIS)

    Godina, J. J.; Li, L.; Meurice, Y.; Oktay, M. B.

    2006-01-01

    The critical exponent γ and its subleading exponent Δ in the 3D O(N) Dyson's hierarchical model for N up to 20 are calculated with high accuracy. We calculate the critical temperatures for the measure δ(φ-vector.φ-vector-1). We extract the first coefficients of the 1/N expansion from our numerical data. We show that the leading and subleading exponents agree with Polchinski equation and the equivalent Litim equation, in the local potential approximation, with at least 4 significant digits

  10. High-accuracy mass determination of unstable nuclei with a Penning trap mass spectrometer

    CERN Multimedia

    2002-01-01

    The mass of a nucleus is its most fundamental property. A systematic study of nuclear masses as a function of neutron and proton number allows the observation of collective and single-particle effects in nuclear structure. Accurate mass data are the most basic test of nuclear models and are essential for their improvement. This is especially important for the astrophysical study of nuclear synthesis. In order to achieve the required high accuracy, the mass of ions captured in a Penning trap is determined via their cyclotron frequency $ \

  11. A variational nodal diffusion method of high accuracy; Varijaciona nodalna difuziona metoda visoke tachnosti

    Energy Technology Data Exchange (ETDEWEB)

    Tomasevic, Dj; Altiparmarkov, D [Institut za Nuklearne Nauke Boris Kidric, Belgrade (Yugoslavia)

    1988-07-01

    A variational nodal diffusion method with accurate treatment of transverse leakage shape is developed and presented in this paper. Using Legendre expansion in transverse coordinates higher order quasi-one-dimensional nodal equations are formulated. Numerical solution has been carried out using analytical solutions in alternating directions assuming Legendre expansion of the RHS term. The method has been tested against 2D and 3D IAEA benchmark problem, as well as 2D CANDU benchmark problem. The results are highly accurate. The first order approximation yields to the same order of accuracy as the standard nodal methods with quadratic leakage approximation, while the second order reaches reference solution. (author)

  12. A new ultra-high-accuracy angle generator: current status and future direction

    Science.gov (United States)

    Guertin, Christian F.; Geckeler, Ralf D.

    2017-09-01

    Lack of an extreme high-accuracy angular positioning device available in the United States has left a gap in industrial and scientific efforts conducted there, requiring certain user groups to undertake time-consuming work with overseas laboratories. Specifically, in x-ray mirror metrology the global research community is advancing the state-of-the-art to unprecedented levels. We aim to fill this U.S. gap by developing a versatile high-accuracy angle generator as a part of the national metrology tool set for x-ray mirror metrology and other important industries. Using an established calibration technique to measure the errors of the encoder scale graduations for full-rotation rotary encoders, we implemented an optimized arrangement of sensors positioned to minimize propagation of calibration errors. Our initial feasibility research shows that upon scaling to a full prototype and including additional calibration techniques we can expect to achieve uncertainties at the level of 0.01 arcsec (50 nrad) or better and offer the immense advantage of a highly automatable and customizable product to the commercial market.

  13. Interferometric Observation of the Highly Polarized SiO Maser Emission from the v = 1, J = 5-4 Transition Associated with VY Canis Majoris

    Science.gov (United States)

    Shinnaga, Hiroko; Moran, James M.; Young, Ken H.; Ho, Paul T. P.

    2004-11-01

    We used the Submillimeter Array to image the SiO maser emission in the v=1, J=5-4 transition associated with the peculiar red supergiant VY Canis Majoris. We identified seven maser components and measured their relative positions and linear polarization properties. Five of the maser components are coincident to within about 150 mas (~200 AU at the distance of 1.5 kpc); most of them may originate in the circumstellar envelope at a radius of about 50 mas from the star along with the SiO masers in the lowest rotational transitions. Our measurements show that two of the maser components may be offset from the inner stellar envelope (at the 3 σ level of significance) and may be part of a larger bipolar outflow associated with VY CMa identified by Shinnaga et al. The strongest maser feature at a velocity of 35.9 km s-1 has a 60% linear polarization, and its polarization direction is aligned with the bipolar axis. Such a high degree of polarization suggests that maser inversion is due to radiative pumping. Five of the other maser features have significant linear polarization.

  14. High Accuracy, Miniature Pressure Sensor for Very High Temperatures, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — SiWave proposes to develop a compact, low-cost MEMS-based pressure sensor for very high temperatures and low pressures in hypersonic wind tunnels. Most currently...

  15. Physics of interferometric gravitational wave detectors

    Indian Academy of Sciences (India)

    The Caltech-MIT joint LIGO project is operating three long-baseline interferometers (one of 2 km and two of 4 km) in order to unambiguously measure the infinitesimal displacements of isolated test masses which convey the signature of gravitational waves from astrophysical sources. An interferometric gravitational wave ...

  16. NiftyPET: a High-throughput Software Platform for High Quantitative Accuracy and Precision PET Imaging and Analysis.

    Science.gov (United States)

    Markiewicz, Pawel J; Ehrhardt, Matthias J; Erlandsson, Kjell; Noonan, Philip J; Barnes, Anna; Schott, Jonathan M; Atkinson, David; Arridge, Simon R; Hutton, Brian F; Ourselin, Sebastien

    2018-01-01

    We present a standalone, scalable and high-throughput software platform for PET image reconstruction and analysis. We focus on high fidelity modelling of the acquisition processes to provide high accuracy and precision quantitative imaging, especially for large axial field of view scanners. All the core routines are implemented using parallel computing available from within the Python package NiftyPET, enabling easy access, manipulation and visualisation of data at any processing stage. The pipeline of the platform starts from MR and raw PET input data and is divided into the following processing stages: (1) list-mode data processing; (2) accurate attenuation coefficient map generation; (3) detector normalisation; (4) exact forward and back projection between sinogram and image space; (5) estimation of reduced-variance random events; (6) high accuracy fully 3D estimation of scatter events; (7) voxel-based partial volume correction; (8) region- and voxel-level image analysis. We demonstrate the advantages of this platform using an amyloid brain scan where all the processing is executed from a single and uniform computational environment in Python. The high accuracy acquisition modelling is achieved through span-1 (no axial compression) ray tracing for true, random and scatter events. Furthermore, the platform offers uncertainty estimation of any image derived statistic to facilitate robust tracking of subtle physiological changes in longitudinal studies. The platform also supports the development of new reconstruction and analysis algorithms through restricting the axial field of view to any set of rings covering a region of interest and thus performing fully 3D reconstruction and corrections using real data significantly faster. All the software is available as open source with the accompanying wiki-page and test data.

  17. A generalized polynomial chaos based ensemble Kalman filter with high accuracy

    International Nuclear Information System (INIS)

    Li Jia; Xiu Dongbin

    2009-01-01

    As one of the most adopted sequential data assimilation methods in many areas, especially those involving complex nonlinear dynamics, the ensemble Kalman filter (EnKF) has been under extensive investigation regarding its properties and efficiency. Compared to other variants of the Kalman filter (KF), EnKF is straightforward to implement, as it employs random ensembles to represent solution states. This, however, introduces sampling errors that affect the accuracy of EnKF in a negative manner. Though sampling errors can be easily reduced by using a large number of samples, in practice this is undesirable as each ensemble member is a solution of the system of state equations and can be time consuming to compute for large-scale problems. In this paper we present an efficient EnKF implementation via generalized polynomial chaos (gPC) expansion. The key ingredients of the proposed approach involve (1) solving the system of stochastic state equations via the gPC methodology to gain efficiency; and (2) sampling the gPC approximation of the stochastic solution with an arbitrarily large number of samples, at virtually no additional computational cost, to drastically reduce the sampling errors. The resulting algorithm thus achieves a high accuracy at reduced computational cost, compared to the classical implementations of EnKF. Numerical examples are provided to verify the convergence property and accuracy improvement of the new algorithm. We also prove that for linear systems with Gaussian noise, the first-order gPC Kalman filter method is equivalent to the exact Kalman filter.

  18. A high accuracy algorithm of displacement measurement for a micro-positioning stage

    Directory of Open Access Journals (Sweden)

    Xiang Zhang

    2017-05-01

    Full Text Available A high accuracy displacement measurement algorithm for a two degrees of freedom compliant precision micro-positioning stage is proposed based on the computer micro-vision technique. The algorithm consists of an integer-pixel and a subpixel matching procedure. Series of simulations are conducted to verify the proposed method. The results show that the proposed algorithm possesses the advantages of high precision and stability, the resolution can attain to 0.01 pixel theoretically. In addition, the consuming time is reduced about 6.7 times compared with the classical normalized cross correlation algorithm. To validate the practical performance of the proposed algorithm, a laser interferometer measurement system (LIMS is built up. The experimental results demonstrate that the algorithm has better adaptability than that of the LIMS.

  19. Prediction of novel pre-microRNAs with high accuracy through boosting and SVM.

    Science.gov (United States)

    Zhang, Yuanwei; Yang, Yifan; Zhang, Huan; Jiang, Xiaohua; Xu, Bo; Xue, Yu; Cao, Yunxia; Zhai, Qian; Zhai, Yong; Xu, Mingqing; Cooke, Howard J; Shi, Qinghua

    2011-05-15

    High-throughput deep-sequencing technology has generated an unprecedented number of expressed short sequence reads, presenting not only an opportunity but also a challenge for prediction of novel microRNAs. To verify the existence of candidate microRNAs, we have to show that these short sequences can be processed from candidate pre-microRNAs. However, it is laborious and time consuming to verify these using existing experimental techniques. Therefore, here, we describe a new method, miRD, which is constructed using two feature selection strategies based on support vector machines (SVMs) and boosting method. It is a high-efficiency tool for novel pre-microRNA prediction with accuracy up to 94.0% among different species. miRD is implemented in PHP/PERL+MySQL+R and can be freely accessed at http://mcg.ustc.edu.cn/rpg/mird/mird.php.

  20. High Accuracy mass Measurement of the very Short-Lived Halo Nuclide $^{11}$Li

    CERN Multimedia

    Le scornet, G

    2002-01-01

    The archetypal halo nuclide $^{11}$Li has now attracted a wealth of experimental and theoretical attention. The most outstanding property of this nuclide, its extended radius that makes it as big as $^{48}$Ca, is highly dependent on the binding energy of the two neutrons forming the halo. New generation experiments using radioactive beams with elastic proton scattering, knock-out and transfer reactions, together with $\\textit{ab initio}$ calculations require the tightening of the constraint on the binding energy. Good metrology also requires confirmation of the sole existing precision result to guard against a possible systematic deviation (or mistake). We propose a high accuracy mass determintation of $^{11}$Li, a particularly challenging task due to its very short half-life of 8.6 ms, but one perfectly suiting the MISTRAL spectrometer, now commissioned at ISOLDE. We request 15 shifts of beam time.

  1. Computer modeling of oil spill trajectories with a high accuracy method

    International Nuclear Information System (INIS)

    Garcia-Martinez, Reinaldo; Flores-Tovar, Henry

    1999-01-01

    This paper proposes a high accuracy numerical method to model oil spill trajectories using a particle-tracking algorithm. The Euler method, used to calculate oil trajectories, can give adequate solutions in most open ocean applications. However, this method may not predict accurate particle trajectories in certain highly non-uniform velocity fields near coastal zones or in river problems. Simple numerical experiments show that the Euler method may also introduce artificial numerical dispersion that could lead to overestimation of spill areas. This article proposes a fourth-order Runge-Kutta method with fourth-order velocity interpolation to calculate oil trajectories that minimise these problems. The algorithm is implemented in the OilTrack model to predict oil trajectories following the 'Nissos Amorgos' oil spill accident that occurred in the Gulf of Venezuela in 1997. Despite lack of adequate field information, model results compare well with observations in the impacted area. (Author)

  2. High data rate atom interferometric device

    Science.gov (United States)

    Biedermann, Grant; McGuinness, Hayden James Evans; Rakholia, Akash

    2015-07-21

    A light-pulse atomic interferometry (LPAI) apparatus is provided. The LPAI apparatus comprises a vessel, two sets of magnetic coils configured to magnetically confine an atomic vapor in two respective magneto-optical traps (MOTs) within the vessel when activated, and an optical system configured to irradiate the atomic vapor within the vessel with laser radiation that, when suitably tuned, can launch atoms previously confined in each of the MOTs toward the other MOT. In embodiments, the magnetic coils are configured to produce a magnetic field that is non-zero at the midpoint between the traps. In embodiments, the time-of-flight of the launched atoms from one MOT to the other is 12 ms or less. In embodiments, the MOTs are situated approximately 36 mm apart. In embodiments, the apparatus is configured to activate the magnetic coils according to a particular temporal magnetic field gradient profile.

  3. Treatment accuracy of hypofractionated spine and other highly conformal IMRT treatments

    International Nuclear Information System (INIS)

    Sutherland, B.; Hanlon, P.; Charles, P.

    2011-01-01

    Full text: Spinal cord metastases pose difficult challenges for radiation treatment due to tight dose constraints and a concave PTY. This project aimed to thoroughly test the treatment accuracy of the Eclipse Treatment Planning System (TPS) for highly modulated IMRT treatments, in particular of the thoracic spine, using an Elekta Synergy Linear Accelerator. The increased understanding obtained through different quality assurance techniques allowed recommendations to be made for treatment site commissioning with improved accuracy at the Princess Alexandra Hospital (PAH). Three thoracic spine IMRT plans at the PAH were used for data collection. Complex phantom models were built using CT data, and fields simulated using Monte Carlo modelling. The simulated dose distributions were compared with the TPS using gamma analysis and DYH comparison. High resolution QA was done for all fields using the MatriXX ion chamber array, MapCHECK2 diode array shifted, and the EPlD to determine a procedure for commissioning new treatment sites. Basic spine simulations found the TPS overestimated absorbed dose to bone, however within spinal cord there was good agreement. High resolution QA found the average gamma pass rate of the fields to be 99.1 % for MatriXX, 96.5% for MapCHECK2 shifted and 97.7% for EPlD. Preliminary results indicate agreement between the TPS and delivered dose distributions higher than previously believed for the investigated IMRT plans. The poor resolution of the MatriXX, and normalisation issues with MapCHECK2 leads to probable recommendation of EPlD for future IMRT commissioning due to the high resolution and minimal setup required.

  4. Data quality studies of enhanced interferometric gravitational wave detectors

    International Nuclear Information System (INIS)

    McIver, Jessica

    2012-01-01

    Data quality assessment plays an essential role in the quest to detect gravitational wave signals in data from the LIGO and Virgo interferometric gravitational wave detectors. Interferometer data contain a high rate of noise transients from the environment, the detector hardware and the detector control systems. These transients severely limit the statistical significance of gravitational wave candidates of short duration and/or poorly modeled waveforms. This paper describes the data quality studies that have been performed in recent LIGO and Virgo observing runs to mitigate the impact of transient detector artifacts on the gravitational wave searches. (paper)

  5. High Accuracy, High Energy He-Erd Analysis of H,C, and T

    International Nuclear Information System (INIS)

    Browning, James F.; Langley, Robert A.; Doyle, Barney L.; Banks, James C.; Wampler, William R.

    1999-01-01

    A new analysis technique using high-energy helium ions for the simultaneous elastic recoil detection of all three hydrogen isotopes in metal hydride systems extending to depths of several microm's is presented. Analysis shows that it is possible to separate each hydrogen isotope in a heavy matrix such as erbium to depths of 5 microm using incident 11.48MeV 4 He 2 ions with a detection system composed of a range foil and ΔE-E telescope detector. Newly measured cross sections for the elastic recoil scattering of 4 He 2 ions from protons and deuterons are presented in the energy range 10 to 11.75 MeV for the laboratory recoil angle of 30degree

  6. PACMAN Project: A New Solution for the High-accuracy Alignment of Accelerator Components

    CERN Document Server

    Mainaud Durand, Helene; Buzio, Marco; Caiazza, Domenico; Catalán Lasheras, Nuria; Cherif, Ahmed; Doytchinov, Iordan; Fuchs, Jean-Frederic; Gaddi, Andrea; Galindo Munoz, Natalia; Gayde, Jean-Christophe; Kamugasa, Solomon; Modena, Michele; Novotny, Peter; Russenschuck, Stephan; Sanz, Claude; Severino, Giordana; Tshilumba, David; Vlachakis, Vasileios; Wendt, Manfred; Zorzetti, Silvia

    2016-01-01

    The beam alignment requirements for the next generation of lepton colliders have become increasingly challenging. As an example, the alignment requirements for the three major collider components of the CLIC linear collider are as follows. Before the first beam circulates, the Beam Position Monitors (BPM), Accelerating Structures (AS)and quadrupoles will have to be aligned up to 10 μm w.r.t. a straight line over 200 m long segments, along the 20 km of linacs. PACMAN is a study on Particle Accelerator Components' Metrology and Alignment to the Nanometre scale. It is an Innovative Doctoral Program, funded by the EU and hosted by CERN, providing high quality training to 10 Early Stage Researchers working towards a PhD thesis. The technical aim of the project is to improve the alignment accuracy of the CLIC components by developing new methods and tools addressing several steps of alignment simultaneously, to gain time and accuracy. The tools and methods developed will be validated on a test bench. This paper pr...

  7. High Accuracy Mass Measurement of the Dripline Nuclides $^{12,14}$Be

    CERN Multimedia

    2002-01-01

    State-of-the art, three-body nuclear models that describe halo nuclides require the binding energy of the halo neutron(s) as a critical input parameter. In the case of $^{14}$Be, the uncertainty of this quantity is currently far too large (130 keV), inhibiting efforts at detailed theoretical description. A high accuracy, direct mass deterlnination of $^{14}$Be (as well as $^{12}$Be to obtain the two-neutron separation energy) is therefore required. The measurement can be performed with the MISTRAL spectrometer, which is presently the only possible solution due to required accuracy (10 keV) and short half-life (4.5 ms). Having achieved a 5 keV uncertainty for the mass of $^{11}$Li (8.6 ms), MISTRAL has proved the feasibility of such measurements. Since the current ISOLDE production rate of $^{14}$Be is only about 10/s, the installation of a beam cooler is underway in order to improve MISTRAL transmission. The projected improvement of an order of magnitude (in each transverse direction) will make this measureme...

  8. Accuracy assessment of NOAA gridded daily reference evapotranspiration for the Texas High Plains

    Science.gov (United States)

    Moorhead, Jerry; Gowda, Prasanna H.; Hobbins, Michael; Senay, Gabriel; Paul, George; Marek, Thomas; Porter, Dana

    2015-01-01

    The National Oceanic and Atmospheric Administration (NOAA) provides daily reference evapotranspiration (ETref) maps for the contiguous United States using climatic data from North American Land Data Assimilation System (NLDAS). This data provides large-scale spatial representation of ETref, which is essential for regional scale water resources management. Data used in the development of NOAA daily ETref maps are derived from observations over surfaces that are different from short (grass — ETos) or tall (alfalfa — ETrs) reference crops, often in nonagricultural settings, which carries an unknown discrepancy between assumed and actual conditions. In this study, NOAA daily ETos and ETrs maps were evaluated for accuracy, using observed data from the Texas High Plains Evapotranspiration (TXHPET) network. Daily ETos, ETrs and the climatic data (air temperature, wind speed, and solar radiation) used for calculating ETref were extracted from the NOAA maps for TXHPET locations and compared against ground measurements on reference grass surfaces. NOAA ETrefmaps generally overestimated the TXHPET observations (1.4 and 2.2 mm/day ETos and ETrs, respectively), which may be attributed to errors in the NLDAS modeled air temperature and wind speed, to which reference ETref is most sensitive. Therefore, a bias correction to NLDAS modeled air temperature and wind speed data, or adjustment to the resulting NOAA ETref, may be needed to improve the accuracy of NOAA ETref maps.

  9. High Accuracy Beam Current Monitor System for CEBAF'S Experimental Hall A

    International Nuclear Information System (INIS)

    J. Denard; A. Saha; G. Lavessiere

    2001-01-01

    CEBAF accelerator delivers continuous wave (CW) electron beams to three experimental Halls. In Hall A, all experiments require continuous, non-invasive current measurements and a few experiments require an absolute accuracy of 0.2 % in the current range from 1 to 180 (micro)A. A Parametric Current Transformer (PCT), manufactured by Bergoz, has an accurate and stable sensitivity of 4 (micro)A/V but its offset drifts at the muA level over time preclude its direct use for continuous measurements. Two cavity monitors are calibrated against the PCT with at least 50 (micro)A of beam current. The calibration procedure suppresses the error due to PCT's offset drifts by turning the beam on and off, which is invasive to the experiment. One of the goals of the system is to minimize the calibration time without compromising the measurement's accuracy. The linearity of the cavity monitors is a critical parameter for transferring the accurate calibration done at high currents over the whole dynamic range. The method for measuring accurately the linearity is described

  10. Medication adherence assessment: high accuracy of the new Ingestible Sensor System in kidney transplants.

    Science.gov (United States)

    Eisenberger, Ute; Wüthrich, Rudolf P; Bock, Andreas; Ambühl, Patrice; Steiger, Jürg; Intondi, Allison; Kuranoff, Susan; Maier, Thomas; Green, Damian; DiCarlo, Lorenzo; Feutren, Gilles; De Geest, Sabina

    2013-08-15

    This open-label single-arm exploratory study evaluated the accuracy of the Ingestible Sensor System (ISS), a novel technology for directly assessing the ingestion of oral medications and treatment adherence. ISS consists of an ingestible event marker (IEM), a microsensor that becomes activated in gastric fluid, and an adhesive personal monitor (APM) that detects IEM activation. In this study, the IEM was combined to enteric-coated mycophenolate sodium (ECMPS). Twenty stable adult kidney transplants received IEM-ECMPS for a mean of 9.2 weeks totaling 1227 cumulative days. Eight patients prematurely discontinued treatment due to ECMPS gastrointestinal symptoms (n=2), skin intolerance to APM (n=2), and insufficient system usability (n=4). Rash or erythema due to APM was reported in 7 (37%) patients, all during the first month of use. No serious or severe adverse events and no rejection episode were reported. IEM detection accuracy was 100% over 34 directly observed ingestions; Taking Adherence was 99.4% over a total of 2824 prescribed IEM-ECMPS ingestions. ISS could detect accurately the ingestion of two IEM-ECMPS capsules taken at the same time (detection rate of 99.3%, n=2376). ISS is a promising new technology that provides highly reliable measurements of intake and timing of intake of drugs that are combined with the IEM.

  11. Combined Scintigraphy and Tumor Marker Analysis Predicts Unfavorable Histopathology of Neuroblastic Tumors with High Accuracy.

    Directory of Open Access Journals (Sweden)

    Wolfgang Peter Fendler

    Full Text Available Our aim was to improve the prediction of unfavorable histopathology (UH in neuroblastic tumors through combined imaging and biochemical parameters.123I-MIBG SPECT and MRI was performed before surgical resection or biopsy in 47 consecutive pediatric patients with neuroblastic tumor. Semi-quantitative tumor-to-liver count-rate ratio (TLCRR, MRI tumor size and margins, urine catecholamine and NSE blood levels of neuron specific enolase (NSE were recorded. Accuracy of single and combined variables for prediction of UH was tested by ROC analysis with Bonferroni correction.34 of 47 patients had UH based on the International Neuroblastoma Pathology Classification (INPC. TLCRR and serum NSE both predicted UH with moderate accuracy. Optimal cut-off for TLCRR was 2.0, resulting in 68% sensitivity and 100% specificity (AUC-ROC 0.86, p < 0.001. Optimal cut-off for NSE was 25.8 ng/ml, resulting in 74% sensitivity and 85% specificity (AUC-ROC 0.81, p = 0.001. Combination of TLCRR/NSE criteria reduced false negative findings from 11/9 to only five, with improved sensitivity and specificity of 85% (AUC-ROC 0.85, p < 0.001.Strong 123I-MIBG uptake and high serum level of NSE were each predictive of UH. Combined analysis of both parameters improved the prediction of UH in patients with neuroblastic tumor. MRI parameters and urine catecholamine levels did not predict UH.

  12. Enhancing the Accuracy of Advanced High Temperature Mechanical Testing through Thermography

    Directory of Open Access Journals (Sweden)

    Jonathan Jones

    2018-03-01

    Full Text Available This paper describes the advantages and enhanced accuracy thermography provides to high temperature mechanical testing. This technique is not only used to monitor, but also to control test specimen temperatures where the infra-red technique enables accurate non-invasive control of rapid thermal cycling for non-metallic materials. Isothermal and dynamic waveforms are employed over a 200–800 °C temperature range to pre-oxidised and coated specimens to assess the capability of the technique. This application shows thermography to be accurate to within ±2 °C of thermocouples, a standardised measurement technique. This work demonstrates the superior visibility of test temperatures previously unobtainable by conventional thermocouples or even more modern pyrometers that thermography can deliver. As a result, the speed and accuracy of thermal profiling, thermal gradient measurements and cold/hot spot identification using the technique has increased significantly to the point where temperature can now be controlled by averaging over a specified area. The increased visibility of specimen temperatures has revealed additional unknown effects such as thermocouple shadowing, preferential crack tip heating within an induction coil, and, fundamental response time of individual measurement techniques which are investigated further.

  13. An output amplitude configurable wideband automatic gain control with high gain step accuracy

    International Nuclear Information System (INIS)

    He Xiaofeng; Ye Tianchun; Mo Taishan; Ma Chengyan

    2012-01-01

    An output amplitude configurable wideband automatic gain control (AGC) with high gain step accuracy for the GNSS receiver is presented. The amplitude of an AGC is configurable in order to cooperate with baseband chips to achieve interference suppression and be compatible with different full range ADCs. And what's more, the gain-boosting technology is introduced and the circuit is improved to increase the step accuracy. A zero, which is composed by the source feedback resistance and the source capacity, is introduced to compensate for the pole. The AGC is fabricated in a 0.18 μm CMOS process. The AGC shows a 62 dB gain control range by 1 dB each step with a gain error of less than 0.2 dB. The AGC provides 3 dB bandwidth larger than 80 MHz and the overall power consumption is less than 1.8 mA, and the die area is 800 × 300 μm 2 . (semiconductor integrated circuits)

  14. High accuracy of family history of melanoma in Danish melanoma cases.

    Science.gov (United States)

    Wadt, Karin A W; Drzewiecki, Krzysztof T; Gerdes, Anne-Marie

    2015-12-01

    The incidence of melanoma in Denmark has immensely increased over the last 10 years making Denmark a high risk country for melanoma. In the last two decades multiple public campaigns have sought to increase the awareness of melanoma. Family history of melanoma is a known major risk factor but previous studies have shown that self-reported family history of melanoma is highly inaccurate. These studies are 15 years old and we wanted to examine if a higher awareness of melanoma has increased the accuracy of self-reported family history of melanoma. We examined the family history of 181 melanoma probands who reported 199 cases of melanoma in relatives, of which 135 cases where in first degree relatives. We confirmed the diagnosis of melanoma in 77% of all relatives, and in 83% of first degree relatives. In 181 probands we validated the negative family history of melanoma in 748 first degree relatives and found only 1 case of melanoma which was not reported in a 3 case melanoma family. Melanoma patients in Denmark report family history of melanoma in first and second degree relatives with a high level of accuracy with a true positive predictive value between 77 and 87%. In 99% of probands reporting a negative family history of melanoma in first degree relatives this information is correct. In clinical practice we recommend that melanoma diagnosis in relatives should be verified if possible, but even unverified reported melanoma cases in relatives should be included in the indication of genetic testing and assessment of melanoma risk in the family.

  15. High accuracy Primary Reference gas Mixtures for high-impact greenhouse gases

    Science.gov (United States)

    Nieuwenkamp, Gerard; Zalewska, Ewelina; Pearce-Hill, Ruth; Brewer, Paul; Resner, Kate; Mace, Tatiana; Tarhan, Tanil; Zellweger, Christophe; Mohn, Joachim

    2017-04-01

    Climate change, due to increased man-made emissions of greenhouse gases, poses one of the greatest risks to society worldwide. High-impact greenhouse gases (CO2, CH4 and N2O) and indirect drivers for global warming (e.g. CO) are measured by the global monitoring stations for greenhouse gases, operated and organized by the World Meteorological Organization (WMO). Reference gases for the calibration of analyzers have to meet very challenging low level of measurement uncertainty to comply with the Data Quality Objectives (DQOs) set by the WMO. Within the framework of the European Metrology Research Programme (EMRP), a project to improve the metrology for high-impact greenhouse gases was granted (HIGHGAS, June 2014-May 2017). As a result of the HIGHGAS project, primary reference gas mixtures in cylinders for ambient levels of CO2, CH4, N2O and CO in air have been prepared with unprecedented low uncertainties, typically 3-10 times lower than usually previously achieved by the NMIs. To accomplish these low uncertainties in the reference standards, a number of preparation and analysis steps have been studied and improved. The purity analysis of the parent gases had to be performed with lower detection limits than previously achievable. E.g., to achieve an uncertainty of 2•10-9 mol/mol (absolute) on the amount fraction for N2O, the detection limit for the N2O analysis in the parent gases has to be in the sub nmol/mol domain. Results of an OPO-CRDS analyzer set-up in the 5µm wavelength domain, with a 200•10-12 mol/mol detection limit for N2O, will be presented. The adsorption effects of greenhouse gas components at cylinder surfaces are critical, and have been studied for different cylinder passivation techniques. Results of a two-year stability study will be presented. The fit-for-purpose of the reference materials was studied for possible variation on isotopic composition between the reference material and the sample. Measurement results for a suit of CO2 in air

  16. Accuracy optimization of high-speed AFM measurements using Design of Experiments

    DEFF Research Database (Denmark)

    Tosello, Guido; Marinello, F.; Hansen, Hans Nørgaard

    2010-01-01

    Atomic Force Microscopy (AFM) is being increasingly employed in industrial micro/nano manufacturing applications and integrated into production lines. In order to achieve reliable process and product control at high measuring speed, instrument optimization is needed. Quantitative AFM measurement...... results are influenced by a number of scan settings parameters, defining topography sampling and measurement time: resolution (number of profiles and points per profile), scan range and direction, scanning force and speed. Such parameters are influencing lateral and vertical accuracy and, eventually......, the estimated dimensions of measured features. The definition of scan settings is based on a comprehensive optimization that targets maximization of information from collected data and minimization of measurement uncertainty and scan time. The Design of Experiments (DOE) technique is proposed and applied...

  17. Recent high-accuracy measurements of the 1S0 neutron-neutron scattering length

    International Nuclear Information System (INIS)

    Howell, C.R.; Chen, Q.; Gonzalez Trotter, D.E.; Salinas, F.; Crowell, A.S.; Roper, C.D.; Tornow, W.; Walter, R.L.; Carman, T.S.; Hussein, A.; Gibbs, W.R.; Gibson, B.F.; Morris, C.; Obst, A.; Sterbenz, S.; Whitton, M.; Mertens, G.; Moore, C.F.; Whiteley, C.R.; Pasyuk, E.; Slaus, I.; Tang, H.; Zhou, Z.; Gloeckle, W.; Witala, H.

    2000-01-01

    This paper reports two recent high-accuracy determinations of the 1 S 0 neutron-neutron scattering length, a nn . One was done at the Los Alamos National Laboratory using the π - d capture reaction to produce two neutrons with low relative momentum. The neutron-deuteron (nd) breakup reaction was used in other measurement, which was conducted at the Triangle Universities Nuclear Laboratory. The results from the two determinations were consistent with each other and with previous values obtained using the π - d capture reaction. The value obtained from the nd breakup measurements is a nn = -18.7 ± 0.1 (statistical) ± 0.6 (systematic) fm, and the value from the π - d capture experiment is a nn = -18.50 ± 0.05 ± 0.53 fm. The recommended value is a nn = -18.5 ± 0.3 fm. (author)

  18. High accuracy amplitude and phase measurements based on a double heterodyne architecture

    International Nuclear Information System (INIS)

    Zhao Danyang; Wang Guangwei; Pan Weimin

    2015-01-01

    In the digital low level RF (LLRF) system of a circular (particle) accelerator, the RF field signal is usually down converted to a fixed intermediate frequency (IF). The ratio of IF and sampling frequency determines the processing required, and differs in various LLRF systems. It is generally desirable to design a universally compatible architecture for different IFs with no change to the sampling frequency and algorithm. A new RF detection method based on a double heterodyne architecture for wide IF range has been developed, which achieves the high accuracy requirement of modern LLRF. In this paper, the relation of IF and phase error is systematically analyzed for the first time and verified by experiments. The effects of temperature drift for 16 h IF detection are inhibited by the amplitude and phase calibrations. (authors)

  19. High-accuracy biodistribution analysis of adeno-associated virus variants by double barcode sequencing.

    Science.gov (United States)

    Marsic, Damien; Méndez-Gómez, Héctor R; Zolotukhin, Sergei

    2015-01-01

    Biodistribution analysis is a key step in the evaluation of adeno-associated virus (AAV) capsid variants, whether natural isolates or produced by rational design or directed evolution. Indeed, when screening candidate vectors, accurate knowledge about which tissues are infected and how efficiently is essential. We describe the design, validation, and application of a new vector, pTR-UF50-BC, encoding a bioluminescent protein, a fluorescent protein and a DNA barcode, which can be used to visualize localization of transduction at the organism, organ, tissue, or cellular levels. In addition, by linking capsid variants to different barcoded versions of the vector and amplifying the barcode region from various tissue samples using barcoded primers, biodistribution of viral genomes can be analyzed with high accuracy and efficiency.

  20. Accuracy and high-speed technique for autoprocessing of Young's fringes

    Science.gov (United States)

    Chen, Wenyi; Tan, Yushan

    1991-12-01

    In this paper, an accurate and high-speed method for auto-processing of Young's fringes is proposed. A group of 1-D sampled intensity values along three or more different directions are taken from Young's fringes, and the fringe spacings of each direction are obtained by 1-D FFT respectively. Two directions that have smaller fringe spacing are selected from all directions. The accurate fringe spacings along these two directions are obtained by using orthogonal coherent phase detection technique (OCPD). The actual spacing and angle of Young's fringes, therefore, can be calculated. In this paper, the principle of OCPD is introduced in detail. The accuracy of the method is evaluated theoretically and experimentally.

  1. DEVELOPMENT OF COMPLEXITY, ACCURACY, AND FLUENCY IN HIGH SCHOOL STUDENTS’ WRITTEN FOREIGN LANGUAGE PRODUCTION

    Directory of Open Access Journals (Sweden)

    Bouchaib Benzehaf

    2016-11-01

    Full Text Available The present study aims to longitudinally depict the dynamic and interactive development of Complexity, Accuracy, and Fluency (CAF in multilingual learners’ L2 and L3 writing. The data sources include free writing tasks written in L2 French and L3 English by 45 high school participants over a period of four semesters. CAF dimensions are measured using a variation of Hunt’s T-units (1964. Analysis of the quantitative data obtained suggests that CAF measures develop differently for learners’ L2 French and L3 English. They increase more persistently in L3 English, and they display the characteristics of a dynamic, non-linear system characterized by ups and downs particularly in L2 French. In light of the results, we suggest more and denser longitudinal data to explore the nature of interactions between these dimensions in foreign language development, particularly at the individual level.

  2. Accuracy of thick-walled hollows during piercing on three-high mill

    International Nuclear Information System (INIS)

    Potapov, I.N.; Romantsev, B.A.; Shamanaev, V.I.; Popov, V.A.; Kharitonov, E.A.

    1975-01-01

    The results of investigations are presented concerning the accuracy of geometrical dimensions of thick-walled sleeves produced by piercing on a 100-ton trio screw rolling mill MISiS with three schemes of fixing and centering the rod. The use of a spherical thrust journal for the rod and of a long centering bushing makes it possible to diminish the non-uniformity of the wall thickness of the sleeves by 30-50%. It is established that thick-walled sleeves with accurate geometrical dimensions (nonuniformity of the wall thickness being less than 10%) can be produced if the system sleeve - mandrel - rod is highly rigid and the rod has a two- or three-fold stability margin over the length equal to that of the sleeve being pierced. The process of piercing is expedient to be carried out with increased angles of feed (14-16 deg). Blanks have been made from steel 12Kh1MF

  3. Integral equation models for image restoration: high accuracy methods and fast algorithms

    International Nuclear Information System (INIS)

    Lu, Yao; Shen, Lixin; Xu, Yuesheng

    2010-01-01

    Discrete models are consistently used as practical models for image restoration. They are piecewise constant approximations of true physical (continuous) models, and hence, inevitably impose bottleneck model errors. We propose to work directly with continuous models for image restoration aiming at suppressing the model errors caused by the discrete models. A systematic study is conducted in this paper for the continuous out-of-focus image models which can be formulated as an integral equation of the first kind. The resulting integral equation is regularized by the Lavrentiev method and the Tikhonov method. We develop fast multiscale algorithms having high accuracy to solve the regularized integral equations of the second kind. Numerical experiments show that the methods based on the continuous model perform much better than those based on discrete models, in terms of PSNR values and visual quality of the reconstructed images

  4. Innovative High-Accuracy Lidar Bathymetric Technique for the Frequent Measurement of River Systems

    Science.gov (United States)

    Gisler, A.; Crowley, G.; Thayer, J. P.; Thompson, G. S.; Barton-Grimley, R. A.

    2015-12-01

    Lidar (light detection and ranging) provides absolute depth and topographic mapping capability compared to other remote sensing methods, which is useful for mapping rapidly changing environments such as riverine systems. Effectiveness of current lidar bathymetric systems is limited by the difficulty in unambiguously identifying backscattered lidar signals from the water surface versus the bottom, limiting their depth resolution to 0.3-0.5 m. Additionally these are large, bulky systems that are constrained to expensive aircraft-mounted platforms and use waveform-processing techniques requiring substantial computation time. These restrictions are prohibitive for many potential users. A novel lidar device has been developed that allows for non-contact measurements of water depth down to 1 cm with an accuracy and precision of shallow to deep water allowing for shoreline charting, measuring water volume, mapping bottom topology, and identifying submerged objects. The scalability of the technique opens up the ability for handheld or UAS-mounted lidar bathymetric systems, which provides for potential applications currently unavailable to the community. The high laser pulse repetition rate allows for very fine horizontal resolution while the photon-counting technique permits real-time depth measurement and object detection. The enhanced measurement capability, portability, scalability, and relatively low-cost creates the opportunity to perform frequent high-accuracy monitoring and measuring of aquatic environments which is crucial for understanding how rivers evolve over many timescales. Results from recent campaigns measuring water depth in flowing creeks and murky ponds will be presented which demonstrate that the method is not limited by rough water surfaces and can map underwater topology through moderately turbid water.

  5. Innovative Technique for High-Accuracy Remote Monitoring of Surface Water

    Science.gov (United States)

    Gisler, A.; Barton-Grimley, R. A.; Thayer, J. P.; Crowley, G.

    2016-12-01

    Lidar (light detection and ranging) provides absolute depth and topographic mapping capability compared to other remote sensing methods, which is useful for mapping rapidly changing environments such as riverine systems and agricultural waterways. Effectiveness of current lidar bathymetric systems is limited by the difficulty in unambiguously identifying backscattered lidar signals from the water surface versus the bottom, limiting their depth resolution to 0.3-0.5 m. Additionally these are large, bulky systems that are constrained to expensive aircraft-mounted platforms and use waveform-processing techniques requiring substantial computation time. These restrictions are prohibitive for many potential users. A novel lidar device has been developed that allows for non-contact measurements of water depth down to 1 cm with an accuracy and precision of shallow to deep water allowing for shoreline charting, measuring water volume, mapping bottom topology, and identifying submerged objects. The scalability of the technique opens up the ability for handheld or UAS-mounted lidar bathymetric systems, which provides for potential applications currently unavailable to the community. The high laser pulse repetition rate allows for very fine horizontal resolution while the photon-counting technique permits real-time depth measurement and object detection. The enhanced measurement capability, portability, scalability, and relatively low-cost creates the opportunity to perform frequent high-accuracy monitoring and measuring of aquatic environments which is crucial for monitoring water resources on fast timescales. Results from recent campaigns measuring water depth in flowing creeks and murky ponds will be presented which demonstrate that the method is not limited by rough water surfaces and can map underwater topology through moderately turbid water.

  6. High-accuracy continuous airborne measurements of greenhouse gases (CO2 and CH4) during BARCA

    Science.gov (United States)

    Chen, H.; Winderlich, J.; Gerbig, C.; Hoefer, A.; Rella, C. W.; Crosson, E. R.; van Pelt, A. D.; Steinbach, J.; Kolle, O.; Beck, V.; Daube, B. C.; Gottlieb, E. W.; Chow, V. Y.; Santoni, G. W.; Wofsy, S. C.

    2009-12-01

    High-accuracy continuous measurements of greenhouse gases (CO2 and CH4) during the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) phase B campaign in Brazil in May 2009 were accomplished using a newly available analyzer based on the cavity ring-down spectroscopy (CRDS) technique. This analyzer was flown without a drying system or any in-flight calibration gases. Water vapor corrections associated with dilution and pressure-broadening effects for CO2 and CH4 were derived from laboratory experiments employing measurements of water vapor by the CRDS analyzer. Before the campaign, the stability of the analyzer was assessed by laboratory tests under simulated flight conditions. During the campaign, a comparison of CO2 measurements between the CRDS analyzer and a nondispersive infrared (NDIR) analyzer on board the same aircraft showed a mean difference of 0.22±0.09 ppm for all flights over the Amazon rain forest. At the end of the campaign, CO2 concentrations of the synthetic calibration gases used by the NDIR analyzer were determined by the CRDS analyzer. After correcting for the isotope and the pressure-broadening effects that resulted from changes of the composition of synthetic vs. ambient air, and applying those concentrations as calibrated values of the calibration gases to reprocess the CO2 measurements made by the NDIR, the mean difference between the CRDS and the NDIR during BARCA was reduced to 0.05±0.09 ppm, with the mean standard deviation of 0.23±0.05 ppm. The results clearly show that the CRDS is sufficiently stable to be used in flight without drying the air or calibrating in flight and the water corrections are fully adequate for high-accuracy continuous airborne measurements of CO2 and CH4.

  7. High-accuracy self-mixing interferometer based on single high-order orthogonally polarized feedback effects.

    Science.gov (United States)

    Zeng, Zhaoli; Qu, Xueming; Tan, Yidong; Tan, Runtao; Zhang, Shulian

    2015-06-29

    A simple and high-accuracy self-mixing interferometer based on single high-order orthogonally polarized feedback effects is presented. The single high-order feedback effect is realized when dual-frequency laser reflects numerous times in a Fabry-Perot cavity and then goes back to the laser resonator along the same route. In this case, two orthogonally polarized feedback fringes with nanoscale resolution are obtained. This self-mixing interferometer has the advantages of higher sensitivity to weak signal than that of conventional interferometer. In addition, two orthogonally polarized fringes are useful for discriminating the moving direction of measured object. The experiment of measuring 2.5nm step is conducted, which shows a great potential in nanometrology.

  8. Advanced interferometric gravitational-wave detectors

    CERN Document Server

    Saulson, Peter R

    2019-01-01

    Gravitational waves are one of the most exciting and promising emerging areas of physics and astrophysics today. The detection of gravitational waves will rank among the most significant physics discoveries of the 21st century.Advanced Interferometric Gravitational-Wave Detectors brings together many of the world's top experts to deliver an authoritative and in-depth treatment on current and future detectors. Volume I is devoted to the essentials of gravitational-wave detectors, presenting the physical principles behind large-scale precision interferometry, the physics of the underlying noise sources that limit interferometer sensitivity, and an explanation of the key enabling technologies that are used in the detectors. Volume II provides an in-depth look at the Advanced LIGO and Advanced Virgo interferometers that have just finished construction, as well as examining future interferometric detector concepts. This two-volume set will provide students and researchers the comprehensive background needed to und...

  9. Focused-laser interferometric position sensor

    International Nuclear Information System (INIS)

    Friedman, Stephen J.; Barwick, Brett; Batelaan, Herman

    2005-01-01

    We describe a simple method to measure the position shifts of an object with a range of tens of micrometers using a focused-laser (FL) interferometric position sensor. In this article we examine the effects of mechanical vibration on FL and Michelson interferometers. We tested both interferometers using vibration amplitudes ranging from 0 to 20 μm. Our FL interferometer has a resolution much better than the diffraction grating periodicities of 10 and 14 μm used in our experiments. A FL interferometer provides improved mechanical stability at the expense of spatial resolution. Our experimental results show that Michelson interferometers cannot be used when the vibration amplitude is more than an optical wavelength. The main purpose of this article is to demonstrate that a focused-laser interferometric position sensor can be used to measure the position shifts of an object on a less sensitive, micrometer scale when the vibration amplitude is too large to use a Michelson interferometer

  10. Accuracy assessment of high resolution satellite imagery orientation by leave-one-out method

    Science.gov (United States)

    Brovelli, Maria Antonia; Crespi, Mattia; Fratarcangeli, Francesca; Giannone, Francesca; Realini, Eugenio

    Interest in high-resolution satellite imagery (HRSI) is spreading in several application fields, at both scientific and commercial levels. Fundamental and critical goals for the geometric use of this kind of imagery are their orientation and orthorectification, processes able to georeference the imagery and correct the geometric deformations they undergo during acquisition. In order to exploit the actual potentialities of orthorectified imagery in Geomatics applications, the definition of a methodology to assess the spatial accuracy achievable from oriented imagery is a crucial topic. In this paper we want to propose a new method for accuracy assessment based on the Leave-One-Out Cross-Validation (LOOCV), a model validation method already applied in different fields such as machine learning, bioinformatics and generally in any other field requiring an evaluation of the performance of a learning algorithm (e.g. in geostatistics), but never applied to HRSI orientation accuracy assessment. The proposed method exhibits interesting features which are able to overcome the most remarkable drawbacks involved by the commonly used method (Hold-Out Validation — HOV), based on the partitioning of the known ground points in two sets: the first is used in the orientation-orthorectification model (GCPs — Ground Control Points) and the second is used to validate the model itself (CPs — Check Points). In fact the HOV is generally not reliable and it is not applicable when a low number of ground points is available. To test the proposed method we implemented a new routine that performs the LOOCV in the software SISAR, developed by the Geodesy and Geomatics Team at the Sapienza University of Rome to perform the rigorous orientation of HRSI; this routine was tested on some EROS-A and QuickBird images. Moreover, these images were also oriented using the world recognized commercial software OrthoEngine v. 10 (included in the Geomatica suite by PCI), manually performing the LOOCV

  11. High-Accuracy Measurements of Total Column Water Vapor From the Orbiting Carbon Observatory-2

    Science.gov (United States)

    Nelson, Robert R.; Crisp, David; Ott, Lesley E.; O'Dell, Christopher W.

    2016-01-01

    Accurate knowledge of the distribution of water vapor in Earth's atmosphere is of critical importance to both weather and climate studies. Here we report on measurements of total column water vapor (TCWV) from hyperspectral observations of near-infrared reflected sunlight over land and ocean surfaces from the Orbiting Carbon Observatory-2 (OCO-2). These measurements are an ancillary product of the retrieval algorithm used to measure atmospheric carbon dioxide concentrations, with information coming from three highly resolved spectral bands. Comparisons to high-accuracy validation data, including ground-based GPS and microwave radiometer data, demonstrate that OCO-2 TCWV measurements have maximum root-mean-square deviations of 0.9-1.3mm. Our results indicate that OCO-2 is the first space-based sensor to accurately and precisely measure the two most important greenhouse gases, water vapor and carbon dioxide, at high spatial resolution [1.3 x 2.3 km(exp. 2)] and that OCO-2 TCWV measurements may be useful in improving numerical weather predictions and reanalysis products.

  12. A new device for liver cancer biomarker detection with high accuracy

    Directory of Open Access Journals (Sweden)

    Shuaipeng Wang

    2015-06-01

    Full Text Available A novel cantilever array-based bio-sensor was batch-fabricated with IC compatible MEMS technology for precise liver cancer bio-marker detection. A micro-cavity was designed in the free end of the cantilever for local antibody-immobilization, thus adsorption of the cancer biomarker is localized in the micro-cavity, and the adsorption-induced k variation can be dramatically reduced with comparison to that caused by adsorption of the whole lever. The cantilever is pizeoelectrically driven into vibration which is pizeoresistively sensed by Wheatstone bridge. These structural features offer several advantages: high sensitivity, high throughput, high mass detection accuracy, and small volume. In addition, an analytical model has been established to eliminate the effect of adsorption-induced lever stiffness change and has been applied to precise mass detection of cancer biomarker AFP, the detected AFP antigen mass (7.6 pg/ml is quite close to the calculated one (5.5 pg/ml, two orders of magnitude better than the value by the fully antibody-immobilized cantilever sensor. These approaches will promote real application of the cantilever sensors in early diagnosis of cancer.

  13. Design and Performance Evaluation of Real-time Endovascular Interventional Surgical Robotic System with High Accuracy.

    Science.gov (United States)

    Wang, Kundong; Chen, Bing; Lu, Qingsheng; Li, Hongbing; Liu, Manhua; Shen, Yu; Xu, Zhuoyan

    2018-05-15

    Endovascular interventional surgery (EIS) is performed under a high radiation environment at the sacrifice of surgeons' health. This paper introduces a novel endovascular interventional surgical robot that aims to reduce radiation to surgeons and physical stress imposed by lead aprons during fluoroscopic X-ray guided catheter intervention. The unique mechanical structure allowed the surgeon to manipulate the axial and radial motion of the catheter and guide wire. Four catheter manipulators (to manipulate the catheter and guide wire), and a control console which consists of four joysticks, several buttons and two twist switches (to control the catheter manipulators) were presented. The entire robotic system was established on a master-slave control structure through CAN (Controller Area Network) bus communication, meanwhile, the slave side of this robotic system showed highly accurate control over velocity and displacement with PID controlling method. The robotic system was tested and passed in vitro and animal experiments. Through functionality evaluation, the manipulators were able to complete interventional surgical motion both independently and cooperatively. The robotic surgery was performed successfully in an adult female pig and demonstrated the feasibility of superior mesenteric and common iliac artery stent implantation. The entire robotic system met the clinical requirements of EIS. The results show that the system has the ability to imitate the movements of surgeons and to accomplish the axial and radial motions with consistency and high-accuracy. Copyright © 2018 John Wiley & Sons, Ltd.

  14. Astigmatism compensation in mode-cleaner cavities for the next generation of gravitational wave interferometric detectors

    Energy Technology Data Exchange (ETDEWEB)

    Barriga, Pablo J. [School of Physics, University of Western Australia, Crawley, WA 6009 (Australia)]. E-mail: pbarriga@cyllene.uwa.edu.au; Zhao Chunnong [School of Physics, University of Western Australia, Crawley, WA 6009 (Australia); Blair, David G. [School of Physics, University of Western Australia, Crawley, WA 6009 (Australia)

    2005-06-06

    Interferometric gravitational wave detectors use triangular ring cavities to filter spatial and frequency instabilities from the input laser beam. The next generation of interferometric detectors will use high laser power and greatly increased circulating power inside the cavities. The increased power inside the cavities increases thermal effects in their mirrors. The triangular configuration of conventional mode-cleaners creates an intrinsic astigmatism that can be corrected by using the thermal effects to advantage. In this Letter we show that an astigmatism free output beam can be created if the design parameters are correctly chosen.

  15. Astigmatism compensation in mode-cleaner cavities for the next generation of gravitational wave interferometric detectors

    International Nuclear Information System (INIS)

    Barriga, Pablo J.; Zhao Chunnong; Blair, David G.

    2005-01-01

    Interferometric gravitational wave detectors use triangular ring cavities to filter spatial and frequency instabilities from the input laser beam. The next generation of interferometric detectors will use high laser power and greatly increased circulating power inside the cavities. The increased power inside the cavities increases thermal effects in their mirrors. The triangular configuration of conventional mode-cleaners creates an intrinsic astigmatism that can be corrected by using the thermal effects to advantage. In this Letter we show that an astigmatism free output beam can be created if the design parameters are correctly chosen

  16. A Robust High-Accuracy Ultrasound Indoor Positioning System Based on a Wireless Sensor Network.

    Science.gov (United States)

    Qi, Jun; Liu, Guo-Ping

    2017-11-06

    This paper describes the development and implementation of a robust high-accuracy ultrasonic indoor positioning system (UIPS). The UIPS consists of several wireless ultrasonic beacons in the indoor environment. Each of them has a fixed and known position coordinate and can collect all the transmissions from the target node or emit ultrasonic signals. Every wireless sensor network (WSN) node has two communication modules: one is WiFi, that transmits the data to the server, and the other is the radio frequency (RF) module, which is only used for time synchronization between different nodes, with accuracy up to 1 μ s. The distance between the beacon and the target node is calculated by measuring the time-of-flight (TOF) for the ultrasonic signal, and then the position of the target is computed by some distances and the coordinate of the beacons. TOF estimation is the most important technique in the UIPS. A new time domain method to extract the envelope of the ultrasonic signals is presented in order to estimate the TOF. This method, with the envelope detection filter, estimates the value with the sampled values on both sides based on the least squares method (LSM). The simulation results show that the method can achieve envelope detection with a good filtering effect by means of the LSM. The highest precision and variance can reach 0.61 mm and 0.23 mm, respectively, in pseudo-range measurements with UIPS. A maximum location error of 10.2 mm is achieved in the positioning experiments for a moving robot, when UIPS works on the line-of-sight (LOS) signal.

  17. High-accuracy optical extensometer based on coordinate transform in two-dimensional digital image correlation

    Science.gov (United States)

    Lv, Zeqian; Xu, Xiaohai; Yan, Tianhao; Cai, Yulong; Su, Yong; Zhang, Qingchuan

    2018-01-01

    In the measurement of plate specimens, traditional two-dimensional (2D) digital image correlation (DIC) is challenged by two aspects: (1) the slant optical axis (misalignment of the optical camera axis and the object surface) and (2) out-of-plane motions (including translations and rotations) of the specimens. There are measurement errors in the results measured by 2D DIC, especially when the out-of-plane motions are big enough. To solve this problem, a novel compensation method has been proposed to correct the unsatisfactory results. The proposed compensation method consists of three main parts: 1) a pre-calibration step is used to determine the intrinsic parameters and lens distortions; 2) a compensation panel (a rigid panel with several markers located at known positions) is mounted to the specimen to track the specimen's motion so that the relative coordinate transformation between the compensation panel and the 2D DIC setup can be calculated using the coordinate transform algorithm; 3) three-dimensional world coordinates of measuring points on the specimen can be reconstructed via the coordinate transform algorithm and used to calculate deformations. Simulations have been carried out to validate the proposed compensation method. Results come out that when the extensometer length is 400 pixels, the strain accuracy reaches 10 με no matter out-of-plane translations (less than 1/200 of the object distance) nor out-of-plane rotations (rotation angle less than 5°) occur. The proposed compensation method leads to good results even when the out-of-plane translation reaches several percents of the object distance or the out-of-plane rotation angle reaches tens of degrees. The proposed compensation method has been applied in tensile experiments to obtain high-accuracy results as well.

  18. A Robust High-Accuracy Ultrasound Indoor Positioning System Based on a Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    Jun Qi

    2017-11-01

    Full Text Available This paper describes the development and implementation of a robust high-accuracy ultrasonic indoor positioning system (UIPS. The UIPS consists of several wireless ultrasonic beacons in the indoor environment. Each of them has a fixed and known position coordinate and can collect all the transmissions from the target node or emit ultrasonic signals. Every wireless sensor network (WSN node has two communication modules: one is WiFi, that transmits the data to the server, and the other is the radio frequency (RF module, which is only used for time synchronization between different nodes, with accuracy up to 1 μs. The distance between the beacon and the target node is calculated by measuring the time-of-flight (TOF for the ultrasonic signal, and then the position of the target is computed by some distances and the coordinate of the beacons. TOF estimation is the most important technique in the UIPS. A new time domain method to extract the envelope of the ultrasonic signals is presented in order to estimate the TOF. This method, with the envelope detection filter, estimates the value with the sampled values on both sides based on the least squares method (LSM. The simulation results show that the method can achieve envelope detection with a good filtering effect by means of the LSM. The highest precision and variance can reach 0.61 mm and 0.23 mm, respectively, in pseudo-range measurements with UIPS. A maximum location error of 10.2 mm is achieved in the positioning experiments for a moving robot, when UIPS works on the line-of-sight (LOS signal.

  19. High accuracy electromagnetic field solvers for cylindrical waveguides and axisymmetric structures using the finite element method

    International Nuclear Information System (INIS)

    Nelson, E.M.

    1993-12-01

    Some two-dimensional finite element electromagnetic field solvers are described and tested. For TE and TM modes in homogeneous cylindrical waveguides and monopole modes in homogeneous axisymmetric structures, the solvers find approximate solutions to a weak formulation of the wave equation. Second-order isoparametric lagrangian triangular elements represent the field. For multipole modes in axisymmetric structures, the solver finds approximate solutions to a weak form of the curl-curl formulation of Maxwell's equations. Second-order triangular edge elements represent the radial (ρ) and axial (z) components of the field, while a second-order lagrangian basis represents the azimuthal (φ) component of the field weighted by the radius ρ. A reduced set of basis functions is employed for elements touching the axis. With this basis the spurious modes of the curl-curl formulation have zero frequency, so spurious modes are easily distinguished from non-static physical modes. Tests on an annular ring, a pillbox and a sphere indicate the solutions converge rapidly as the mesh is refined. Computed eigenvalues with relative errors of less than a few parts per million are obtained. Boundary conditions for symmetric, periodic and symmetric-periodic structures are discussed and included in the field solver. Boundary conditions for structures with inversion symmetry are also discussed. Special corner elements are described and employed to improve the accuracy of cylindrical waveguide and monopole modes with singular fields at sharp corners. The field solver is applied to three problems: (1) cross-field amplifier slow-wave circuits, (2) a detuned disk-loaded waveguide linear accelerator structure and (3) a 90 degrees overmoded waveguide bend. The detuned accelerator structure is a critical application of this high accuracy field solver. To maintain low long-range wakefields, tight design and manufacturing tolerances are required

  20. The One to Multiple Automatic High Accuracy Registration of Terrestrial LIDAR and Optical Images

    Science.gov (United States)

    Wang, Y.; Hu, C.; Xia, G.; Xue, H.

    2018-04-01

    The registration of ground laser point cloud and close-range image is the key content of high-precision 3D reconstruction of cultural relic object. In view of the requirement of high texture resolution in the field of cultural relic at present, The registration of point cloud and image data in object reconstruction will result in the problem of point cloud to multiple images. In the current commercial software, the two pairs of registration of the two kinds of data are realized by manually dividing point cloud data, manual matching point cloud and image data, manually selecting a two - dimensional point of the same name of the image and the point cloud, and the process not only greatly reduces the working efficiency, but also affects the precision of the registration of the two, and causes the problem of the color point cloud texture joint. In order to solve the above problems, this paper takes the whole object image as the intermediate data, and uses the matching technology to realize the automatic one-to-one correspondence between the point cloud and multiple images. The matching of point cloud center projection reflection intensity image and optical image is applied to realize the automatic matching of the same name feature points, and the Rodrigo matrix spatial similarity transformation model and weight selection iteration are used to realize the automatic registration of the two kinds of data with high accuracy. This method is expected to serve for the high precision and high efficiency automatic 3D reconstruction of cultural relic objects, which has certain scientific research value and practical significance.

  1. High-resolution CT of nontuberculous mycobacterium infection in adult CF patients: diagnostic accuracy

    International Nuclear Information System (INIS)

    McEvoy, Sinead; Lavelle, Lisa; Kilcoyne, Aoife; McCarthy, Colin; Dodd, Jonathan D.; DeJong, Pim A.; Loeve, Martine; Tiddens, Harm A.W.M.; McKone, Edward; Gallagher, Charles G.

    2012-01-01

    To determine the diagnostic accuracy of high-resolution computed tomography (HRCT) for the detection of nontuberculous mycobacterium infection (NTM) in adult cystic fibrosis (CF) patients. Twenty-seven CF patients with sputum-culture-proven NTM (NTM+) underwent HRCT. An age, gender and spirometrically matched group of 27 CF patients without NTM (NTM-) was included as controls. Images were randomly and blindly analysed by two readers in consensus and scored using a modified Bhalla scoring system. Significant differences were seen between NTM (+) and NTM (-) patients in the severity of the bronchiectasis subscore [45 % (1.8/4) vs. 35 % (1.4/4), P = 0.029], collapse/consolidation subscore [33 % (1.3/3) vs. 15 % (0.6/3)], tree-in-bud/centrilobular nodules subscore [43 % (1.7/3) vs. 25 % (1.0/3), P = 0.002] and the total CT score [56 % (18.4/33) vs. 46 % (15.2/33), P = 0.002]. Binary logistic regression revealed BMI, peribronchial thickening, collapse/consolidation and tree-in-bud/centrilobular nodules to be predictors of NTM status (R 2 = 0.43). Receiver-operator curve analysis of the regression model showed an area under the curve of 0.89, P < 0.0001. In adults with CF, seven or more bronchopulmonary segments showing tree-in-bud/centrilobular nodules on HRCT is highly suggestive of NTM colonisation. (orig.)

  2. High-resolution CT of nontuberculous mycobacterium infection in adult CF patients: diagnostic accuracy

    Energy Technology Data Exchange (ETDEWEB)

    McEvoy, Sinead; Lavelle, Lisa; Kilcoyne, Aoife; McCarthy, Colin; Dodd, Jonathan D. [St. Vincent' s University Hospital, Department of Radiology, Dublin (Ireland); DeJong, Pim A. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Loeve, Martine; Tiddens, Harm A.W.M. [Erasmus MC-Sophia Children' s Hospital, Department of Radiology, Department of Pediatric Pulmonology and Allergology, Rotterdam (Netherlands); McKone, Edward; Gallagher, Charles G. [St. Vincent' s University Hospital, Department of Respiratory Medicine and National Referral Centre for Adult Cystic Fibrosis, Dublin (Ireland)

    2012-12-15

    To determine the diagnostic accuracy of high-resolution computed tomography (HRCT) for the detection of nontuberculous mycobacterium infection (NTM) in adult cystic fibrosis (CF) patients. Twenty-seven CF patients with sputum-culture-proven NTM (NTM+) underwent HRCT. An age, gender and spirometrically matched group of 27 CF patients without NTM (NTM-) was included as controls. Images were randomly and blindly analysed by two readers in consensus and scored using a modified Bhalla scoring system. Significant differences were seen between NTM (+) and NTM (-) patients in the severity of the bronchiectasis subscore [45 % (1.8/4) vs. 35 % (1.4/4), P = 0.029], collapse/consolidation subscore [33 % (1.3/3) vs. 15 % (0.6/3)], tree-in-bud/centrilobular nodules subscore [43 % (1.7/3) vs. 25 % (1.0/3), P = 0.002] and the total CT score [56 % (18.4/33) vs. 46 % (15.2/33), P = 0.002]. Binary logistic regression revealed BMI, peribronchial thickening, collapse/consolidation and tree-in-bud/centrilobular nodules to be predictors of NTM status (R{sup 2} = 0.43). Receiver-operator curve analysis of the regression model showed an area under the curve of 0.89, P < 0.0001. In adults with CF, seven or more bronchopulmonary segments showing tree-in-bud/centrilobular nodules on HRCT is highly suggestive of NTM colonisation. (orig.)

  3. Rigorous Training of Dogs Leads to High Accuracy in Human Scent Matching-To-Sample Performance.

    Directory of Open Access Journals (Sweden)

    Sophie Marchal

    Full Text Available Human scent identification is based on a matching-to-sample task in which trained dogs are required to compare a scent sample collected from an object found at a crime scene to that of a suspect. Based on dogs' greater olfactory ability to detect and process odours, this method has been used in forensic investigations to identify the odour of a suspect at a crime scene. The excellent reliability and reproducibility of the method largely depend on rigor in dog training. The present study describes the various steps of training that lead to high sensitivity scores, with dogs matching samples with 90% efficiency when the complexity of the scents presented during the task in the sample is similar to that presented in the in lineups, and specificity reaching a ceiling, with no false alarms in human scent matching-to-sample tasks. This high level of accuracy ensures reliable results in judicial human scent identification tests. Also, our data should convince law enforcement authorities to use these results as official forensic evidence when dogs are trained appropriately.

  4. Spline-based high-accuracy piecewise-polynomial phase-to-sinusoid amplitude converters.

    Science.gov (United States)

    Petrinović, Davor; Brezović, Marko

    2011-04-01

    We propose a method for direct digital frequency synthesis (DDS) using a cubic spline piecewise-polynomial model for a phase-to-sinusoid amplitude converter (PSAC). This method offers maximum smoothness of the output signal. Closed-form expressions for the cubic polynomial coefficients are derived in the spectral domain and the performance analysis of the model is given in the time and frequency domains. We derive the closed-form performance bounds of such DDS using conventional metrics: rms and maximum absolute errors (MAE) and maximum spurious free dynamic range (SFDR) measured in the discrete time domain. The main advantages of the proposed PSAC are its simplicity, analytical tractability, and inherent numerical stability for high table resolutions. Detailed guidelines for a fixed-point implementation are given, based on the algebraic analysis of all quantization effects. The results are verified on 81 PSAC configurations with the output resolutions from 5 to 41 bits by using a bit-exact simulation. The VHDL implementation of a high-accuracy DDS based on the proposed PSAC with 28-bit input phase word and 32-bit output value achieves SFDR of its digital output signal between 180 and 207 dB, with a signal-to-noise ratio of 192 dB. Its implementation requires only one 18 kB block RAM and three 18-bit embedded multipliers in a typical field-programmable gate array (FPGA) device. © 2011 IEEE

  5. Development and Evaluation of Science and Technology Education Program Using Interferometric SAR

    Science.gov (United States)

    Ito, Y.; Ikemitsu, H.; Nango, K.

    2016-06-01

    This paper proposes a science and technology education program to teach junior high school students to measure terrain changes by using interferometric synthetic aperture radar (SAR). The objectives of the proposed program are to evaluate and use information technology by performing SAR data processing in order to measure ground deformation, and to incorporate an understanding of Earth sciences by analyzing interferometric SAR processing results. To draft the teaching guidance plan for the developed education program, this study considers both science and technology education. The education program was used in a Japanese junior high school. An educational SAR processor developed by the authors and the customized Delft object-oriented radar interferometric software package were employed. Earthquakes as diastrophism events were chosen as practical teaching materials. The selected events indicate clear ground deformation in differential interferograms with high coherence levels. The learners were able to investigate the ground deformations and disasters caused by the events. They interactively used computers and became skilled at recognizing the knowledge and techniques of information technology, and then they evaluated the technology. Based on the results of pre- and post-questionnaire surveys and self-evaluation by the learners, it was clarified that the proposed program was applicable for junior high school education, and the learners recognized the usefulness of Earth observation technology by using interferometric SAR. The usefulness of the teaching materials in the learning activities was also shown through the practical teaching experience.

  6. Design and simulation of high accuracy power supplies for injector synchrotron dipole magnets

    International Nuclear Information System (INIS)

    Fathizadeh, M.

    1991-01-01

    The ring magnet of the injector synchrotron consists of 68 dipole magnets. These magnets are connected in series and are energized from two feed points 180 degrees apart by two identical 12-phase power supplies. The current in the magnet will be raised linearly at about 1 kA level, and after a small transition period (1 ms to 10 ms typical) the current will be reduced to below the injection level of 60 A. The repetition time for the current waveform is 500 ms. A relatively fast voltage loop along with a high gain current loop are utilized to control the current in the magnet with the required accuracy. Only one regulator circuit is used to control the firing pulses of the two sets of identical 12-phase power supplies. Pspice software was used to design and simulate the power supply performance under ramping and investigate the effect of current changes on the utility voltage and input power factor. A current ripple of ±2x10 -4 and tracking error of ±5x10 -4 was needed. 3 refs., 5 figs

  7. High accuracy line positions of the ν 1 fundamental band of 14 N 2 16 O

    KAUST Repository

    Alsaif, Bidoor

    2018-03-08

    The ν1 fundamental band of N2O is examined by a novel spectrometer that relies on the frequency locking of an external-cavity quantum cascade laser around 7.8 μm to a near-infrared Tm:based frequency comb at 1.9 μm. Due to the large tunability, nearly 70 lines in the 1240 – 1310 cm−1 range of the ν1 band of N2O, from P(40) to R(31), are for the first time measured with an absolute frequency calibration and an uncertainty from 62 to 180 kHz, depending on the line. Accurate values of the spectroscopic constants of the upper state are derived from a fit of the line centers (rms ≈ 4.8 × 10−6 cm−1 or 144 kHz). The ν1 transitions presently measured in a Doppler regime validate high accuracy predictions based on sub-Doppler measurements of the ν3 and ν3-ν1 transitions.

  8. Coronary CT angiography using prospective ECG triggering. High diagnostic accuracy with low radiation dose

    International Nuclear Information System (INIS)

    Arnoldi, E.; Ramos-Duran, L.; Abro, J.A.; Costello, P.; Zwerner, P.L.; Schoepf, U.J.; Nikolaou, K.; Reiser, M.F.

    2010-01-01

    The purpose of this study was to evaluate the diagnostic performance of coronary CT angiography (coronary CTA) using prospective ECG triggering (PT) for the detection of significant coronary artery stenosis compared to invasive coronary angiography (ICA). A total of 20 patients underwent coronary CTA with PT using a 128-slice CT scanner (Definition trademark AS+, Siemens) and ICA. All coronary CTA studies were evaluated for significant coronary artery stenoses (≥50% luminal narrowing) by 2 observers in consensus using the AHA-15-segment model. Findings in CTA were compared to those in ICA. Coronary CTA using PT had 88% sensitivity in comparison to 100% with ICA, 95% to 88% specificity, 80% to 92% positive predictive value and 97% to 100% negative predictive value for diagnosing significant coronary artery stenosis on per segment per patient analysis, respectively. Mean effective radiation dose-equivalent of CTA was 2.6±1 mSv. Coronary CTA using PT enables non-invasive diagnosis of significant coronary artery stenosis with high diagnostic accuracy in comparison to ICA and is associated with comparably low radiation exposure. (orig.) [de

  9. High accuracy line positions of the ν1 fundamental band of 14N216O

    Science.gov (United States)

    AlSaif, Bidoor; Lamperti, Marco; Gatti, Davide; Laporta, Paolo; Fermann, Martin; Farooq, Aamir; Lyulin, Oleg; Campargue, Alain; Marangoni, Marco

    2018-05-01

    The ν1 fundamental band of N2O is examined by a novel spectrometer that relies on the frequency locking of an external-cavity quantum cascade laser around 7.8 μm to a near-infrared Tm:based frequency comb at 1.9 μm. Due to the large tunability, nearly 70 lines in the 1240-1310 cm-1 range of the ν1 band of N2O, from P(40) to R(31), are for the first time measured with an absolute frequency calibration and an uncertainty from 62 to 180 kHz, depending on the line. Accurate values of the spectroscopic constants of the upper state are derived from a fit of the line centers (rms ≈ 4.8 × 10-6 cm-1 or 144 kHz). The ν1 transitions presently measured in a Doppler regime validate high accuracy predictions based on sub-Doppler measurements of the ν3 and ν3-ν1 transitions.

  10. On the impact of improved dosimetric accuracy on head and neck high dose rate brachytherapy.

    Science.gov (United States)

    Peppa, Vasiliki; Pappas, Eleftherios; Major, Tibor; Takácsi-Nagy, Zoltán; Pantelis, Evaggelos; Papagiannis, Panagiotis

    2016-07-01

    To study the effect of finite patient dimensions and tissue heterogeneities in head and neck high dose rate brachytherapy. The current practice of TG-43 dosimetry was compared to patient specific dosimetry obtained using Monte Carlo simulation for a sample of 22 patient plans. The dose distributions were compared in terms of percentage dose differences as well as differences in dose volume histogram and radiobiological indices for the target and organs at risk (mandible, parotids, skin, and spinal cord). Noticeable percentage differences exist between TG-43 and patient specific dosimetry, mainly at low dose points. Expressed as fractions of the planning aim dose, percentage differences are within 2% with a general TG-43 overestimation except for the spine. These differences are consistent resulting in statistically significant differences of dose volume histogram and radiobiology indices. Absolute differences of these indices are however small to warrant clinical importance in terms of tumor control or complication probabilities. The introduction of dosimetry methods characterized by improved accuracy is a valuable advancement. It does not appear however to influence dose prescription or call for amendment of clinical recommendations for the mobile tongue, base of tongue, and floor of mouth patient cohort of this study. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  11. Design and simulation of high accuracy power supplies for injector synchrotron dipole magnets

    International Nuclear Information System (INIS)

    Fathizadeh, M.

    1991-01-01

    The ring magnet of the injector synchrotron consists of 68 dipole magnets. These magnets are connected in series and are energized from two feed points 180 degree apart by two identical 12-phase power supplies. The current in the magnet will be raised linearly to about 1 kA level, and after a small transition period (1 ms to 10 ms typical) the current will be reduced to below the injection level of 60 A. The repetition time for the current waveform is 500 ms. A relatively fast voltage loop along with a high gain current loop are utilized to control the current in the magnet with the required accuracy. Only one regulator circuit is used to control the firing pulses of the two sets of identical 12-phase power supplies. Pspice software was used to design and simulate the power supply performance under ramping and investigate the effect of current changes on the utility voltage and input power factor. A current ripple of ± 2 x 10 -4 and tracking error of ± 5 x 10 -4 was needed

  12. Quantitative accuracy of serotonergic neurotransmission imaging with high-resolution 123I SPECT

    International Nuclear Information System (INIS)

    Kuikka, J.T.

    2004-01-01

    Aim: Serotonin transporter (SERT) imaging can be used to study the role of regional abnormalities of neurotransmitter release in various mental disorders and to study the mechanism of action of therapeutic drugs or drugs' abuse. We examine the quantitative accuracy and reproducibility that can be achieved with high-resolution SPECT of serotonergic neurotransmission. Method: Binding potential (BP) of 123 I labeled tracer specific for midbrain SERT was assessed in 20 healthy persons. The effects of scatter, attenuation, partial volume, misregistration and statistical noise were estimated using phantom and human studies. Results: Without any correction, BP was underestimated by 73%. The partial volume error was the major component in this underestimation whereas the most critical error for the reproducibility was misplacement of region of interest (ROI). Conclusion: The proper ROI registration, the use of the multiple head gamma camera with transmission based scatter correction introduce more relevant results. However, due to the small dimensions of the midbrain SERT structures and poor spatial resolution of SPECT, the improvement without the partial volume correction is not great enough to restore the estimate of BP to that of the true one. (orig.) [de

  13. High Accuracy Ground-based near-Earth-asteroid Astrometry using Synthetic Tracking

    Science.gov (United States)

    Zhai, Chengxing; Shao, Michael; Saini, Navtej; Sandhu, Jagmit; Werne, Thomas; Choi, Philip; Ely, Todd A.; Jacobs, Chirstopher S.; Lazio, Joseph; Martin-Mur, Tomas J.; Owen, William M.; Preston, Robert; Turyshev, Slava; Michell, Adam; Nazli, Kutay; Cui, Isaac; Monchama, Rachel

    2018-01-01

    Accurate astrometry is crucial for determining the orbits of near-Earth-asteroids (NEAs). Further, the future of deep space high data rate communications is likely to be optical communications, such as the Deep Space Optical Communications package that is part of the baseline payload for the planned Psyche Discovery mission to the Psyche asteroid. We have recently upgraded our instrument on the Pomona College 1 m telescope, at JPL's Table Mountain Facility, for conducting synthetic tracking by taking many short exposure images. These images can be then combined in post-processing to track both asteroid and reference stars to yield accurate astrometry. Utilizing the precision of the current and future Gaia data releases, the JPL-Pomona College effort is now demonstrating precision astrometry on NEAs, which is likely to be of considerable value for cataloging NEAs. Further, treating NEAs as proxies of future spacecraft that carry optical communication lasers, our results serve as a measure of the astrometric accuracy that could be achieved for future plane-of-sky optical navigation.

  14. Optimal design of a high accuracy photoelectric auto-collimator based on position sensitive detector

    Science.gov (United States)

    Yan, Pei-pei; Yang, Yong-qing; She, Wen-ji; Liu, Kai; Jiang, Kai; Duan, Jing; Shan, Qiusha

    2018-02-01

    A kind of high accuracy Photo-electric auto-collimator based on PSD was designed. The integral structure composed of light source, optical lens group, Position Sensitive Detector (PSD) sensor, and its hardware and software processing system constituted. Telephoto objective optical type is chosen during the designing process, which effectively reduces the length, weight and volume of the optical system, as well as develops simulation-based design and analysis of the auto-collimator optical system. The technical indicators of auto-collimator presented by this paper are: measuring resolution less than 0.05″; a field of view is 2ω=0.4° × 0.4° measuring range is +/-5' error of whole range measurement is less than 0.2″. Measuring distance is 10m, which are applicable to minor-angle precise measuring environment. Aberration analysis indicates that the MTF close to the diffraction limit, the spot in the spot diagram is much smaller than the Airy disk. The total length of the telephoto lens is only 450mm by the design of the optical machine structure optimization. The autocollimator's dimension get compact obviously under the condition of the image quality is guaranteed.

  15. Review of The SIAM 100-Digit Challenge: A Study in High-Accuracy Numerical Computing

    International Nuclear Information System (INIS)

    Bailey, David

    2005-01-01

    In the January 2002 edition of SIAM News, Nick Trefethen announced the '$100, 100-Digit Challenge'. In this note he presented ten easy-to-state but hard-to-solve problems of numerical analysis, and challenged readers to find each answer to ten-digit accuracy. Trefethen closed with the enticing comment: 'Hint: They're hard. If anyone gets 50 digits in total, I will be impressed.' This challenge obviously struck a chord in hundreds of numerical mathematicians worldwide, as 94 teams from 25 nations later submitted entries. Many of these submissions exceeded the target of 50 correct digits; in fact, 20 teams achieved a perfect score of 100 correct digits. Trefethen had offered $100 for the best submission. Given the overwhelming response, a generous donor (William Browning, founder of Applied Mathematics, Inc.) provided additional funds to provide a $100 award to each of the 20 winning teams. Soon after the results were out, four participants, each from a winning team, got together and agreed to write a book about the problems and their solutions. The team is truly international: Bornemann is from Germany, Laurie is from South Africa, Wagon is from the USA, and Waldvogel is from Switzerland. This book provides some mathematical background for each problem, and then shows in detail how each of them can be solved. In fact, multiple solution techniques are mentioned in each case. The book describes how to extend these solutions to much larger problems and much higher numeric precision (hundreds or thousands of digit accuracy). The authors also show how to compute error bounds for the results, so that one can say with confidence that one's results are accurate to the level stated. Numerous numerical software tools are demonstrated in the process, including the commercial products Mathematica, Maple and Matlab. Computer programs that perform many of the algorithms mentioned in the book are provided, both in an appendix to the book and on a website. In the process, the

  16. River Delta Subsidence Measured with Interferometric Synthetic Aperture Radar (InSAR)

    Science.gov (United States)

    Higgins, Stephanie

    This thesis addresses the need for high-resolution subsidence maps of major world river deltas. Driven by a combination of rising water, sediment compaction, and reduced sediment supply due to damming and flood control, many deltas are sinking relative to sea level. A lack of data constraining rates and patterns of subsidence has made it difficult to determine the relative contributions of each factor in any given delta, however, or to assess whether the primary drivers of land subsidence are natural or anthropogenic. In recent years, Interferometric Synthetic Aperture Radar (InSAR) has emerged as a satellite-based technique that can map ground deformation with mm-scale accuracy over thousands of square kilometers. These maps could provide critical insight into the drivers of subsidence in deltas, but InSAR is not typically applied to non-urban delta areas due to the difficulties of performing the technique in wet, vegetated settings. This thesis addresses those difficulties and achieves high-resolution measurements of ground deformation in rural deltaic areas. Chapter 1 introduces the processes that drive relative sea level rise in river deltas and investigates open questions in delta subsidence research. Chapter 2 assesses the performance of InSAR in delta settings and reviews interferogram generation in the context of delta analysis, presenting delta-specific processing details and guiding interpretation in these challenging areas. Chapter 3 applies Differential (D-) InSAR to the coast of the Yellow River Delta in China. Results show that subsidence rates are as high as 250 mm/y due to groundwater extraction at aquaculture facilities, a rate that exceeds local and global average sea level rise by nearly two orders of magnitude and suggests a significant hazard for Asian megadeltas. Chapter 4 applies interferometric stacking and Small Baseline Subset (SBAS)-InSAR to the Ganges-Brahmaputra Delta, Bangladesh. Results show that stratigraphy controls subsidence in

  17. Achieving numerical accuracy and high performance using recursive tile LU factorization with partial pivoting

    KAUST Repository

    Dongarra, Jack

    2013-09-18

    The LU factorization is an important numerical algorithm for solving systems of linear equations in science and engineering and is a characteristic of many dense linear algebra computations. For example, it has become the de facto numerical algorithm implemented within the LINPACK benchmark to rank the most powerful supercomputers in the world, collected by the TOP500 website. Multicore processors continue to present challenges to the development of fast and robust numerical software due to the increasing levels of hardware parallelism and widening gap between core and memory speeds. In this context, the difficulty in developing new algorithms for the scientific community resides in the combination of two goals: achieving high performance while maintaining the accuracy of the numerical algorithm. This paper proposes a new approach for computing the LU factorization in parallel on multicore architectures, which not only improves the overall performance but also sustains the numerical quality of the standard LU factorization algorithm with partial pivoting. While the update of the trailing submatrix is computationally intensive and highly parallel, the inherently problematic portion of the LU factorization is the panel factorization due to its memory-bound characteristic as well as the atomicity of selecting the appropriate pivots. Our approach uses a parallel fine-grained recursive formulation of the panel factorization step and implements the update of the trailing submatrix with the tile algorithm. Based on conflict-free partitioning of the data and lockless synchronization mechanisms, our implementation lets the overall computation flow naturally without contention. The dynamic runtime system called QUARK is then able to schedule tasks with heterogeneous granularities and to transparently introduce algorithmic lookahead. The performance results of our implementation are competitive compared to the currently available software packages and libraries. For example

  18. Reduced Set of Virulence Genes Allows High Accuracy Prediction of Bacterial Pathogenicity in Humans

    Science.gov (United States)

    Iraola, Gregorio; Vazquez, Gustavo; Spangenberg, Lucía; Naya, Hugo

    2012-01-01

    Although there have been great advances in understanding bacterial pathogenesis, there is still a lack of integrative information about what makes a bacterium a human pathogen. The advent of high-throughput sequencing technologies has dramatically increased the amount of completed bacterial genomes, for both known human pathogenic and non-pathogenic strains; this information is now available to investigate genetic features that determine pathogenic phenotypes in bacteria. In this work we determined presence/absence patterns of different virulence-related genes among more than finished bacterial genomes from both human pathogenic and non-pathogenic strains, belonging to different taxonomic groups (i.e: Actinobacteria, Gammaproteobacteria, Firmicutes, etc.). An accuracy of 95% using a cross-fold validation scheme with in-fold feature selection is obtained when classifying human pathogens and non-pathogens. A reduced subset of highly informative genes () is presented and applied to an external validation set. The statistical model was implemented in the BacFier v1.0 software (freely available at ), that displays not only the prediction (pathogen/non-pathogen) and an associated probability for pathogenicity, but also the presence/absence vector for the analyzed genes, so it is possible to decipher the subset of virulence genes responsible for the classification on the analyzed genome. Furthermore, we discuss the biological relevance for bacterial pathogenesis of the core set of genes, corresponding to eight functional categories, all with evident and documented association with the phenotypes of interest. Also, we analyze which functional categories of virulence genes were more distinctive for pathogenicity in each taxonomic group, which seems to be a completely new kind of information and could lead to important evolutionary conclusions. PMID:22916122

  19. Achieving numerical accuracy and high performance using recursive tile LU factorization with partial pivoting

    KAUST Repository

    Dongarra, Jack; Faverge, Mathieu; Ltaief, Hatem; Luszczek, Piotr R.

    2013-01-01

    The LU factorization is an important numerical algorithm for solving systems of linear equations in science and engineering and is a characteristic of many dense linear algebra computations. For example, it has become the de facto numerical algorithm implemented within the LINPACK benchmark to rank the most powerful supercomputers in the world, collected by the TOP500 website. Multicore processors continue to present challenges to the development of fast and robust numerical software due to the increasing levels of hardware parallelism and widening gap between core and memory speeds. In this context, the difficulty in developing new algorithms for the scientific community resides in the combination of two goals: achieving high performance while maintaining the accuracy of the numerical algorithm. This paper proposes a new approach for computing the LU factorization in parallel on multicore architectures, which not only improves the overall performance but also sustains the numerical quality of the standard LU factorization algorithm with partial pivoting. While the update of the trailing submatrix is computationally intensive and highly parallel, the inherently problematic portion of the LU factorization is the panel factorization due to its memory-bound characteristic as well as the atomicity of selecting the appropriate pivots. Our approach uses a parallel fine-grained recursive formulation of the panel factorization step and implements the update of the trailing submatrix with the tile algorithm. Based on conflict-free partitioning of the data and lockless synchronization mechanisms, our implementation lets the overall computation flow naturally without contention. The dynamic runtime system called QUARK is then able to schedule tasks with heterogeneous granularities and to transparently introduce algorithmic lookahead. The performance results of our implementation are competitive compared to the currently available software packages and libraries. For example

  20. Factors Determining the Inter-observer Variability and Diagnostic Accuracy of High-resolution Manometry for Esophageal Motility Disorders.

    Science.gov (United States)

    Kim, Ji Hyun; Kim, Sung Eun; Cho, Yu Kyung; Lim, Chul-Hyun; Park, Moo In; Hwang, Jin Won; Jang, Jae-Sik; Oh, Minkyung

    2018-01-30

    Although high-resolution manometry (HRM) has the advantage of visual intuitiveness, its diagnostic validity remains under debate. The aim of this study was to evaluate the diagnostic accuracy of HRM for esophageal motility disorders. Six staff members and 8 trainees were recruited for the study. In total, 40 patients enrolled in manometry studies at 3 institutes were selected. Captured images of 10 representative swallows and a single swallow in analyzing mode in both high-resolution pressure topography (HRPT) and conventional line tracing formats were provided with calculated metrics. Assessments of esophageal motility disorders showed fair agreement for HRPT and moderate agreement for conventional line tracing (κ = 0.40 and 0.58, respectively). With the HRPT format, the k value was higher in category A (esophagogastric junction [EGJ] relaxation abnormality) than in categories B (major body peristalsis abnormalities with intact EGJ relaxation) and C (minor body peristalsis abnormalities or normal body peristalsis with intact EGJ relaxation). The overall exact diagnostic accuracy for the HRPT format was 58.8% and rater's position was an independent factor for exact diagnostic accuracy. The diagnostic accuracy for major disorders was 63.4% with the HRPT format. The frequency of major discrepancies was higher for category B disorders than for category A disorders (38.4% vs 15.4%; P < 0.001). The interpreter's experience significantly affected the exact diagnostic accuracy of HRM for esophageal motility disorders. The diagnostic accuracy for major disorders was higher for achalasia than distal esophageal spasm and jackhammer esophagus.

  1. DIRECT GEOREFERENCING : A NEW STANDARD IN PHOTOGRAMMETRY FOR HIGH ACCURACY MAPPING

    Directory of Open Access Journals (Sweden)

    A. Rizaldy

    2012-07-01

    Full Text Available Direct georeferencing is a new method in photogrammetry, especially in the digital camera era. Theoretically, this method does not require ground control points (GCP and the Aerial Triangulation (AT, to process aerial photography into ground coordinates. Compared with the old method, this method has three main advantages: faster data processing, simple workflow and less expensive project, at the same accuracy. Direct georeferencing using two devices, GPS and IMU. GPS recording the camera coordinates (X, Y, Z, and IMU recording the camera orientation (omega, phi, kappa. Both parameters merged into Exterior Orientation (EO parameter. This parameters required for next steps in the photogrammetric projects, such as stereocompilation, DSM generation, orthorectification and mosaic. Accuracy of this method was tested on topographic map project in Medan, Indonesia. Large-format digital camera Ultracam X from Vexcel is used, while the GPS / IMU is IGI AeroControl. 19 Independent Check Point (ICP were used to determine the accuracy. Horizontal accuracy is 0.356 meters and vertical accuracy is 0.483 meters. Data with this accuracy can be used for 1:2.500 map scale project.

  2. Towards Building Reliable, High-Accuracy Solar Irradiance Database For Arid Climates

    Science.gov (United States)

    Munawwar, S.; Ghedira, H.

    2012-12-01

    Middle East's growing interest in renewable energy has led to increased activity in solar technology development with the recent commissioning of several utility-scale solar power projects and many other commercial installations across the Arabian Peninsula. The region, lying in a virtually rainless sunny belt with a typical daily average solar radiation exceeding 6 kWh/m2, is also one of the most promising candidates for solar energy deployment. However, it is not the availability of resource, but its characterization and reasonably accurate assessment that determines the application potential. Solar irradiance, magnitude and variability inclusive, is the key input in assessing the economic feasibility of a solar system. The accuracy of such data is of critical importance for realistic on-site performance estimates. This contribution aims to identify the key stages in developing a robust solar database for desert climate by focusing on the challenges that an arid environment presents to parameterization of solar irradiance attenuating factors. Adjustments are proposed based on the currently available resource assessment tools to produce high quality data for assessing bankability. Establishing and maintaining ground solar irradiance measurements is an expensive affair and fairly limited in time (recently operational) and space (fewer sites) in the Gulf region. Developers within solar technology industry, therefore, rely on solar radiation models and satellite-derived data for prompt resource assessment needs. It is imperative that such estimation tools are as accurate as possible. While purely empirical models have been widely researched and validated in the Arabian Peninsula's solar modeling history, they are known to be intrinsically site-specific. A primal step to modeling is an in-depth understanding of the region's climate, identifying the key players attenuating radiation and their appropriate characterization to determine solar irradiance. Physical approach

  3. Matterwave interferometric velocimetry of cold Rb atoms

    Science.gov (United States)

    Carey, Max; Belal, Mohammad; Himsworth, Matthew; Bateman, James; Freegarde, Tim

    2018-03-01

    We consider the matterwave interferometric measurement of atomic velocities, which forms a building block for all matterwave inertial measurements. A theoretical analysis, addressing both the laboratory and atomic frames and accounting for residual Doppler sensitivity in the beamsplitter and recombiner pulses, is followed by an experimental demonstration, with measurements of the velocity distribution within a 20 ?K cloud of rubidium atoms. Our experiments use Raman transitions between the long-lived ground hyperfine states, and allow quadrature measurements that yield the full complex interferometer signal and hence discriminate between positive and negative velocities. The technique is most suitable for measurement of colder samples.

  4. Light-pulse atom interferometric device

    Science.gov (United States)

    Biedermann, Grant; McGuinness, Hayden James Evans; Rakholia, Akash; Jau, Yuan-Yu; Schwindt, Peter; Wheeler, David R.

    2016-03-22

    An atomic interferometric device useful, e.g., for measuring acceleration or rotation is provided. The device comprises at least one vapor cell containing a Raman-active chemical species, an optical system, and at least one detector. The optical system is conformed to implement a Raman pulse interferometer in which Raman transitions are stimulated in a warm vapor of the Raman-active chemical species. The detector is conformed to detect changes in the populations of different internal states of atoms that have been irradiated by the optical system.

  5. The research of digital circuit system for high accuracy CCD of portable Raman spectrometer

    Science.gov (United States)

    Yin, Yu; Cui, Yongsheng; Zhang, Xiuda; Yan, Huimin

    2013-08-01

    The Raman spectrum technology is widely used for it can identify various types of molecular structure and material. The portable Raman spectrometer has become a hot direction of the spectrometer development nowadays for its convenience in handheld operation and real-time detection which is superior to traditional Raman spectrometer with heavy weight and bulky size. But there is still a gap for its measurement sensitivity between portable and traditional devices. However, portable Raman Spectrometer with Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy (SHINERS) technology can enhance the Raman signal significantly by several orders of magnitude, giving consideration in both measurement sensitivity and mobility. This paper proposed a design and implementation of driver and digital circuit for high accuracy CCD sensor, which is core part of portable spectrometer. The main target of the whole design is to reduce the dark current generation rate and increase signal sensitivity during the long integration time, and in the weak signal environment. In this case, we use back-thinned CCD image sensor from Hamamatsu Corporation with high sensitivity, low noise and large dynamic range. In order to maximize this CCD sensor's performance and minimize the whole size of the device simultaneously to achieve the project indicators, we delicately designed a peripheral circuit for the CCD sensor. The design is mainly composed with multi-voltage circuit, sequential generation circuit, driving circuit and A/D transition parts. As the most important power supply circuit, the multi-voltage circuits with 12 independent voltages are designed with reference power supply IC and set to specified voltage value by the amplifier making up the low-pass filter, which allows the user to obtain a highly stable and accurate voltage with low noise. What's more, to make our design easy to debug, CPLD is selected to generate sequential signal. The A/D converter chip consists of a correlated

  6. In-depth, high-accuracy proteomics of sea urchin tooth organic matrix

    Directory of Open Access Journals (Sweden)

    Mann Matthias

    2008-12-01

    Full Text Available Abstract Background The organic matrix contained in biominerals plays an important role in regulating mineralization and in determining biomineral properties. However, most components of biomineral matrices remain unknown at present. In sea urchin tooth, which is an important model for developmental biology and biomineralization, only few matrix components have been identified. The recent publication of the Strongylocentrotus purpuratus genome sequence rendered possible not only the identification of genes potentially coding for matrix proteins, but also the direct identification of proteins contained in matrices of skeletal elements by in-depth, high-accuracy proteomic analysis. Results We identified 138 proteins in the matrix of tooth powder. Only 56 of these proteins were previously identified in the matrices of test (shell and spine. Among the novel components was an interesting group of five proteins containing alanine- and proline-rich neutral or basic motifs separated by acidic glycine-rich motifs. In addition, four of the five proteins contained either one or two predicted Kazal protease inhibitor domains. The major components of tooth matrix were however largely identical to the set of spicule matrix proteins and MSP130-related proteins identified in test (shell and spine matrix. Comparison of the matrices of crushed teeth to intact teeth revealed a marked dilution of known intracrystalline matrix proteins and a concomitant increase in some intracellular proteins. Conclusion This report presents the most comprehensive list of sea urchin tooth matrix proteins available at present. The complex mixture of proteins identified may reflect many different aspects of the mineralization process. A comparison between intact tooth matrix, presumably containing odontoblast remnants, and crushed tooth matrix served to differentiate between matrix components and possible contributions of cellular remnants. Because LC-MS/MS-based methods directly

  7. Automated, high accuracy classification of Parkinsonian disorders: a pattern recognition approach.

    Directory of Open Access Journals (Sweden)

    Andre F Marquand

    Full Text Available Progressive supranuclear palsy (PSP, multiple system atrophy (MSA and idiopathic Parkinson's disease (IPD can be clinically indistinguishable, especially in the early stages, despite distinct patterns of molecular pathology. Structural neuroimaging holds promise for providing objective biomarkers for discriminating these diseases at the single subject level but all studies to date have reported incomplete separation of disease groups. In this study, we employed multi-class pattern recognition to assess the value of anatomical patterns derived from a widely available structural neuroimaging sequence for automated classification of these disorders. To achieve this, 17 patients with PSP, 14 with IPD and 19 with MSA were scanned using structural MRI along with 19 healthy controls (HCs. An advanced probabilistic pattern recognition approach was employed to evaluate the diagnostic value of several pre-defined anatomical patterns for discriminating the disorders, including: (i a subcortical motor network; (ii each of its component regions and (iii the whole brain. All disease groups could be discriminated simultaneously with high accuracy using the subcortical motor network. The region providing the most accurate predictions overall was the midbrain/brainstem, which discriminated all disease groups from one another and from HCs. The subcortical network also produced more accurate predictions than the whole brain and all of its constituent regions. PSP was accurately predicted from the midbrain/brainstem, cerebellum and all basal ganglia compartments; MSA from the midbrain/brainstem and cerebellum and IPD from the midbrain/brainstem only. This study demonstrates that automated analysis of structural MRI can accurately predict diagnosis in individual patients with Parkinsonian disorders, and identifies distinct patterns of regional atrophy particularly useful for this process.

  8. High accuracy of arterial spin labeling perfusion imaging in differentiation of pilomyxoid from pilocytic astrocytoma

    Energy Technology Data Exchange (ETDEWEB)

    Nabavizadeh, S.A.; Assadsangabi, R.; Hajmomenian, M.; Vossough, A. [Perelman School of Medicine of the University of Pennsylvania, Department of Radiology, Children' s Hospital of Philadelphia, Philadelphia, PA (United States); Santi, M. [Perelman School of Medicine of the University of Pennsylvania, Department of Pathology, Children' s Hospital of Philadelphia, Philadelphia, PA (United States)

    2015-05-01

    Pilomyxoid astrocytoma (PMA) is a relatively new tumor entity which has been added to the 2007 WHO Classification of tumors of the central nervous system. The goal of this study is to utilize arterial spin labeling (ASL) perfusion imaging to differentiate PMA from pilocytic astrocytoma (PA). Pulsed ASL and conventional MRI sequences of patients with PMA and PA in the past 5 years were retrospectively evaluated. Patients with history of radiation or treatment with anti-angiogenic drugs were excluded. A total of 24 patients (9 PMA, 15 PA) were included. There were statistically significant differences between PMA and PA in mean tumor/gray matter (GM) cerebral blood flow (CBF) ratios (1.3 vs 0.4, p < 0.001) and maximum tumor/GM CBF ratio (2.3 vs 1, p < 0.001). Area under the receiver operating characteristic (ROC) curves for differentiation of PMA from PA was 0.91 using mean tumor CBF, 0.95 using mean tumor/GM CBF ratios, and 0.89 using maximum tumor/GM CBF. Using a threshold value of 0.91, the mean tumor/GM CBF ratio was able to diagnose PMA with 77 % sensitivity, 100 % specificity, and a threshold value of 0.7, provided 88 % sensitivity and 86 % specificity. There was no statistically significant difference between the two tumors in enhancement pattern (p = 0.33), internal architecture (p = 0.15), or apparent diffusion coefficient (ADC) values (p = 0.07). ASL imaging has high accuracy in differentiating PMA from PA. The result of this study may have important applications in prognostication and treatment planning especially in patients with less accessible tumors such as hypothalamic-chiasmatic gliomas. (orig.)

  9. Functional knowledge transfer for high-accuracy prediction of under-studied biological processes.

    Directory of Open Access Journals (Sweden)

    Christopher Y Park

    Full Text Available A key challenge in genetics is identifying the functional roles of genes in pathways. Numerous functional genomics techniques (e.g. machine learning that predict protein function have been developed to address this question. These methods generally build from existing annotations of genes to pathways and thus are often unable to identify additional genes participating in processes that are not already well studied. Many of these processes are well studied in some organism, but not necessarily in an investigator's organism of interest. Sequence-based search methods (e.g. BLAST have been used to transfer such annotation information between organisms. We demonstrate that functional genomics can complement traditional sequence similarity to improve the transfer of gene annotations between organisms. Our method transfers annotations only when functionally appropriate as determined by genomic data and can be used with any prediction algorithm to combine transferred gene function knowledge with organism-specific high-throughput data to enable accurate function prediction. We show that diverse state-of-art machine learning algorithms leveraging functional knowledge transfer (FKT dramatically improve their accuracy in predicting gene-pathway membership, particularly for processes with little experimental knowledge in an organism. We also show that our method compares favorably to annotation transfer by sequence similarity. Next, we deploy FKT with state-of-the-art SVM classifier to predict novel genes to 11,000 biological processes across six diverse organisms and expand the coverage of accurate function predictions to processes that are often ignored because of a dearth of annotated genes in an organism. Finally, we perform in vivo experimental investigation in Danio rerio and confirm the regulatory role of our top predicted novel gene, wnt5b, in leftward cell migration during heart development. FKT is immediately applicable to many bioinformatics

  10. High accuracy subwavelength distance measurements: A variable-angle standing-wave total-internal-reflection optical microscope

    International Nuclear Information System (INIS)

    Haynie, A.; Min, T.-J.; Luan, L.; Mu, W.; Ketterson, J. B.

    2009-01-01

    We describe an extension of the total-internal-reflection microscopy technique that permits direct in-plane distance measurements with high accuracy (<10 nm) over a wide range of separations. This high position accuracy arises from the creation of a standing evanescent wave and the ability to sweep the nodal positions (intensity minima of the standing wave) in a controlled manner via both the incident angle and the relative phase of the incoming laser beams. Some control over the vertical resolution is available through the ability to scan the incoming angle and with it the evanescent penetration depth.

  11. High-accuracy dosimetry study for intensity-modulated radiation therapy(IMRT) commissioning

    International Nuclear Information System (INIS)

    Jeong, Hae Sun

    2010-02-01

    Intensity-modulated radiation therapy (IMRT), an advanced modality of high-precision radiotherapy, allows for an increase in dose to the tumor volume without increasing the dose to nearby critical organs. In order to successfully achieve the treatment, intensive dosimetry with accurate dose verification is necessary. A dosimetry for IMRT, however, is a challenging task due to dosimetric ally unfavorable phenomena such as dramatic changes of the dose at the field boundaries, dis-equilibrium of the electrons, non-uniformity between the detector and the phantom materials, and distortion of scanner-read doses. In the present study, therefore, the LEGO-type multi-purpose dosimetry phantom was developed and used for the studies on dose measurements and correction. Phantom materials for muscle, fat, bone, and lung tissue were selected after considering mass density, atomic composition, effective atomic number, and photon interaction coefficients. The phantom also includes dosimeter holders for several different types of detectors including films, which accommodates a construction of different designs of phantoms as necessary. In order to evaluate its performance, the developed phantom was tested by measuring the point dose and the percent depth dose (PDD) for small size fields under several heterogeneous conditions. However, the measurements with the two types of dosimeter did not agree well for the field sizes less than 1 x 1 cm 2 in muscle and bone, and less than 3 x 3 cm 2 in air cavity. Thus, it was recognized that several studies on small fields dosimetry and correction methods for the calculation with a PMCEPT code are needed. The under-estimated values from the ion chamber were corrected with a convolution method employed to eliminate the volume effect of the chamber. As a result, the discrepancies between the EBT film and the ion chamber measurements were significantly decreased, from 14% to 1% (1 x 1 cm 2 ), 10% to 1% (0.7 x 0.7 cm 2 ), and 42% to 7% (0.5 x 0

  12. High-accuracy dosimetry study for intensity-modulated radiation therapy(IMRT) commissioning

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hae Sun

    2010-02-15

    Intensity-modulated radiation therapy (IMRT), an advanced modality of high-precision radiotherapy, allows for an increase in dose to the tumor volume without increasing the dose to nearby critical organs. In order to successfully achieve the treatment, intensive dosimetry with accurate dose verification is necessary. A dosimetry for IMRT, however, is a challenging task due to dosimetric ally unfavorable phenomena such as dramatic changes of the dose at the field boundaries, dis-equilibrium of the electrons, non-uniformity between the detector and the phantom materials, and distortion of scanner-read doses. In the present study, therefore, the LEGO-type multi-purpose dosimetry phantom was developed and used for the studies on dose measurements and correction. Phantom materials for muscle, fat, bone, and lung tissue were selected after considering mass density, atomic composition, effective atomic number, and photon interaction coefficients. The phantom also includes dosimeter holders for several different types of detectors including films, which accommodates a construction of different designs of phantoms as necessary. In order to evaluate its performance, the developed phantom was tested by measuring the point dose and the percent depth dose (PDD) for small size fields under several heterogeneous conditions. However, the measurements with the two types of dosimeter did not agree well for the field sizes less than 1 x 1 cm{sup 2} in muscle and bone, and less than 3 x 3 cm{sup 2} in air cavity. Thus, it was recognized that several studies on small fields dosimetry and correction methods for the calculation with a PMCEPT code are needed. The under-estimated values from the ion chamber were corrected with a convolution method employed to eliminate the volume effect of the chamber. As a result, the discrepancies between the EBT film and the ion chamber measurements were significantly decreased, from 14% to 1% (1 x 1 cm{sup 2}), 10% to 1% (0.7 x 0.7 cm{sup 2}), and 42

  13. Accurate formulas for the penalty caused by interferometric crosstalk

    DEFF Research Database (Denmark)

    Rasmussen, Christian Jørgen; Liu, Fenghai; Jeppesen, Palle

    2000-01-01

    New simple formulas for the penalty caused by interferometric crosstalk in PIN receiver systems and optically preamplified receiver systems are presented. They are more accurate than existing formulas.......New simple formulas for the penalty caused by interferometric crosstalk in PIN receiver systems and optically preamplified receiver systems are presented. They are more accurate than existing formulas....

  14. Interferometric interpolation of sparse marine data

    KAUST Repository

    Hanafy, Sherif M.

    2013-10-11

    We present the theory and numerical results for interferometrically interpolating 2D and 3D marine surface seismic profiles data. For the interpolation of seismic data we use the combination of a recorded Green\\'s function and a model-based Green\\'s function for a water-layer model. Synthetic (2D and 3D) and field (2D) results show that the seismic data with sparse receiver intervals can be accurately interpolated to smaller intervals using multiples in the data. An up- and downgoing separation of both recorded and model-based Green\\'s functions can help in minimizing artefacts in a virtual shot gather. If the up- and downgoing separation is not possible, noticeable artefacts will be generated in the virtual shot gather. As a partial remedy we iteratively use a non-stationary 1D multi-channel matching filter with the interpolated data. Results suggest that a sparse marine seismic survey can yield more information about reflectors if traces are interpolated by interferometry. Comparing our results to those of f-k interpolation shows that the synthetic example gives comparable results while the field example shows better interpolation quality for the interferometric method. © 2013 European Association of Geoscientists & Engineers.

  15. Probing interferometric parallax with interplanetary spacecraft

    Science.gov (United States)

    Rodeghiero, G.; Gini, F.; Marchili, N.; Jain, P.; Ralston, J. P.; Dallacasa, D.; Naletto, G.; Possenti, A.; Barbieri, C.; Franceschini, A.; Zampieri, L.

    2017-07-01

    We describe an experimental scenario for testing a novel method to measure distance and proper motion of astronomical sources. The method is based on multi-epoch observations of amplitude or intensity correlations between separate receiving systems. This technique is called Interferometric Parallax, and efficiently exploits phase information that has traditionally been overlooked. The test case we discuss combines amplitude correlations of signals from deep space interplanetary spacecraft with those from distant galactic and extragalactic radio sources with the goal of estimating the interplanetary spacecraft distance. Interferometric parallax relies on the detection of wavefront curvature effects in signals collected by pairs of separate receiving systems. The method shows promising potentialities over current techniques when the target is unresolved from the background reference sources. Developments in this field might lead to the construction of an independent, geometrical cosmic distance ladder using a dedicated project and future generation instruments. We present a conceptual overview supported by numerical estimates of its performances applied to a spacecraft orbiting the Solar System. Simulations support the feasibility of measurements with a simple and time-saving observational scheme using current facilities.

  16. Effects of Target Positioning Error on Motion Compensation for Airborne Interferometric SAR

    Directory of Open Access Journals (Sweden)

    Li Yin-wei

    2013-12-01

    Full Text Available The measurement inaccuracies of Inertial Measurement Unit/Global Positioning System (IMU/GPS as well as the positioning error of the target may contribute to the residual uncompensated motion errors in the MOtion COmpensation (MOCO approach based on the measurement of IMU/GPS. Aiming at the effects of target positioning error on MOCO for airborne interferometric SAR, the paper firstly deduces a mathematical model of residual motion error bring out by target positioning error under the condition of squint. And the paper analyzes the effects on the residual motion error caused by system sampling delay error, the Doppler center frequency error and reference DEM error which result in target positioning error based on the model. Then, the paper discusses the effects of the reference DEM error on the interferometric SAR image quality, the interferometric phase and the coherent coefficient. The research provides theoretical bases for the MOCO precision in signal processing of airborne high precision SAR and airborne repeat-pass interferometric SAR.

  17. Analysis of the plasmodium falciparum proteome by high-accuracy mass spectrometry

    DEFF Research Database (Denmark)

    Lasonder, Edwin; Ishihama, Yasushi; Andersen, Jens S

    2002-01-01

    -accuracy (average deviation less than 0.02 Da at 1,000 Da) mass spectrometric proteome analysis of selected stages of the human malaria parasite Plasmodium falciparum. The analysis revealed 1,289 proteins of which 714 proteins were identified in asexual blood stages, 931 in gametocytes and 645 in gametes. The last...

  18. [Accuracy of placenta accreta prenatal diagnosis by ultrasound and MRI in a high-risk population].

    Science.gov (United States)

    Daney de Marcillac, F; Molière, S; Pinton, A; Weingertner, A-S; Fritz, G; Viville, B; Roedlich, M-N; Gaudineau, A; Sananes, N; Favre, R; Nisand, I; Langer, B

    2016-02-01

    Main objective was to compare accuracy of ultrasonography and MRI for antenatal diagnosis of placenta accreta. Secondary objectives were to specify the most common sonographic and RMI signs associated with diagnosis of placenta accreta. This retrospective study used data collected from all potential cases of placenta accreta (patients with an anterior placenta praevia with history of scarred uterus) admitted from 01/2010 to 12/2014 in a level III maternity unit in Strasbourg, France. High-risk patients beneficiated antenatally from ultrasonography and MRI. Sonographic signs registered were: abnormal placental lacunae, increased vascularity on color Doppler, absence of the retroplacental clear space, interrupted bladder line. MRI signs registered were: abnormal uterine bulging, intraplacental bands of low signal intensity on T2-weighted images, increased vascularity, heterogeneous signal of the placenta on T2-weighed, interrupted bladder line, protrusion of the placenta into the cervix. Diagnosis of placenta accreta was confirmed histologically after hysterectomy or clinically in case of successful conservative treatment. Twenty-two potential cases of placenta accreta were referred to our center and underwent both ultrasonography and MRI. All cases of placenta accreta had a placenta praevia associated with history of scarred uterus. Sensibility and specificity for ultrasonography were, respectively, 0.92 and 0.67, for MRI 0.84 and 0.78 without significant difference (p>0.05). The most relevant signs associated with diagnosis of placenta accreta in ultrasonography were increased vascularity on color Doppler (sensibility 0.85/specificity 0.78), abnormal placental lacunae (sensibility 0.92/specificity 0.55) and loss of retroplacental clear space (sensibility 0.76/specificity 1.0). The most relevant signs in MRI were: abnormal uterine bulging (sensitivity 0.92/specificity 0.89), dark intraplacental bands on T2-weighted images (sensitivity 0.83/specificity 0.80) or

  19. Interferometric system with tracking refractometry capability in the measuring axis

    International Nuclear Information System (INIS)

    Lazar, J; Holá, M; Číp, O; Hrabina, J; Oulehla, J

    2013-01-01

    We present a combined interferometric arrangement designed for measurement of one-axis displacement over a specified measuring range with mechanical referencing. This concept allows simultaneous measurement of the carriage position from both sides together with monitoring of the overall range. This can be used in configuration with in-line monitoring of the fluctuations of the refractive index-–tracking refractometry. Similarly, the wavelength of the laser source can be stabilized over the measuring range, effectively compensating for the refractive index changes. Otherwise, monitoring of length of the measuring range can give information about the thermal dilatation effects of frame of the whole measuring setup. This technique can find its way into high-precision positioning systems in nanometrology. (technical design note)

  20. Redundant interferometric calibration as a complex optimization problem

    Science.gov (United States)

    Grobler, T. L.; Bernardi, G.; Kenyon, J. S.; Parsons, A. R.; Smirnov, O. M.

    2018-05-01

    Observations of the redshifted 21 cm line from the epoch of reionization have recently motivated the construction of low-frequency radio arrays with highly redundant configurations. These configurations provide an alternative calibration strategy - `redundant calibration' - and boost sensitivity on specific spatial scales. In this paper, we formulate calibration of redundant interferometric arrays as a complex optimization problem. We solve this optimization problem via the Levenberg-Marquardt algorithm. This calibration approach is more robust to initial conditions than current algorithms and, by leveraging an approximate matrix inversion, allows for further optimization and an efficient implementation (`redundant STEFCAL'). We also investigated using the preconditioned conjugate gradient method as an alternative to the approximate matrix inverse, but found that its computational performance is not competitive with respect to `redundant STEFCAL'. The efficient implementation of this new algorithm is made publicly available.

  1. Low-redundancy linear arrays in mirrored interferometric aperture synthesis.

    Science.gov (United States)

    Zhu, Dong; Hu, Fei; Wu, Liang; Li, Jun; Lang, Liang

    2016-01-15

    Mirrored interferometric aperture synthesis (MIAS) is a novel interferometry that can improve spatial resolution compared with that of conventional IAS. In one-dimensional (1-D) MIAS, antenna array with low redundancy has the potential to achieve a high spatial resolution. This Letter presents a technique for the direct construction of low-redundancy linear arrays (LRLAs) in MIAS and derives two regular analytical patterns that can yield various LRLAs in short computation time. Moreover, for a better estimation of the observed scene, a bi-measurement method is proposed to handle the rank defect associated with the transmatrix of those LRLAs. The results of imaging simulation demonstrate the effectiveness of the proposed method.

  2. Multi-path interferometric Josephson directional amplifier for qubit readout

    Science.gov (United States)

    Abdo, Baleegh; Bronn, Nicholas T.; Jinka, Oblesh; Olivadese, Salvatore; Brink, Markus; Chow, Jerry M.

    2018-04-01

    We realize and characterize a quantum-limited, directional Josephson amplifier suitable for qubit readout. The device consists of two nondegenerate, three-wave-mixing amplifiers that are coupled together in an interferometric scheme, embedded in a printed circuit board. Nonreciprocity is generated by applying a phase gradient between the same-frequency pumps feeding the device, which plays the role of the magnetic field in a Faraday medium. Directional amplification and reflection-gain elimination are induced via wave interference between multiple paths in the system. We measure and discuss the main figures of merit of the device and show that the experimental results are in good agreement with theory. An improved version of this directional amplifier is expected to eliminate the need for bulky, off-chip isolation stages that generally separate quantum systems and preamplifiers in high-fidelity, quantum-nondemolition measurement setups.

  3. Accuracy of High-Resolution MRI with Lumen Distention in Rectal Cancer Staging and Circumferential Margin Involvement Prediction

    International Nuclear Information System (INIS)

    Iannicelli, Elsa; Di Renzo, Sara; Ferri, Mario; Pilozzi, Emanuela; Di Girolamo, Marco; Sapori, Alessandra; Ziparo, Vincenzo; David, Vincenzo

    2014-01-01

    To evaluate the accuracy of magnetic resonance imaging (MRI) with lumen distention for rectal cancer staging and circumferential resection margin (CRM) involvement prediction. Seventy-three patients with primary rectal cancer underwent high-resolution MRI with a phased-array coil performed using 60-80 mL room air rectal distention, 1-3 weeks before surgery. MRI results were compared to postoperative histopathological findings. The overall MRI T staging accuracy was calculated. CRM involvement prediction and the N staging, the accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were assessed for each T stage. The agreement between MRI and histological results was assessed using weighted-kappa statistics. The overall MRI accuracy for T staging was 93.6% (k = 0.85). The accuracy, sensitivity, specificity, PPV and NPV for each T stage were as follows: 91.8%, 86.2%, 95.5%, 92.6% and 91.3% for the group ≤ T2; 90.4%, 94.6%, 86.1%, 87.5% and 94% for T3; 98,6%, 85.7%, 100%, 100% and 98.5% for T4, respectively. The predictive CRM accuracy was 94.5% (k = 0.86); the sensitivity, specificity, PPV and NPV were 89.5%, 96.3%, 89.5%, and 96.3% respectively. The N staging accuracy was 68.49% (k = 0.4). MRI performed with rectal lumen distention has proved to be an effective technique both for rectal cancer staging and involved CRM predicting

  4. Accuracy of High-Resolution MRI with Lumen Distention in Rectal Cancer Staging and Circumferential Margin Involvement Prediction

    Energy Technology Data Exchange (ETDEWEB)

    Iannicelli, Elsa; Di Renzo, Sara [Radiology Institute, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Department of Surgical and Medical Sciences and Translational Medicine, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Ferri, Mario [Department of Surgical and Medical Sciences and Translational Medicine, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Pilozzi, Emanuela [Department of Clinical and Molecular Sciences, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Di Girolamo, Marco; Sapori, Alessandra [Radiology Institute, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Department of Surgical and Medical Sciences and Translational Medicine, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Ziparo, Vincenzo [Department of Surgical and Medical Sciences and Translational Medicine, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); David, Vincenzo [Radiology Institute, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Department of Surgical and Medical Sciences and Translational Medicine, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy)

    2014-07-01

    To evaluate the accuracy of magnetic resonance imaging (MRI) with lumen distention for rectal cancer staging and circumferential resection margin (CRM) involvement prediction. Seventy-three patients with primary rectal cancer underwent high-resolution MRI with a phased-array coil performed using 60-80 mL room air rectal distention, 1-3 weeks before surgery. MRI results were compared to postoperative histopathological findings. The overall MRI T staging accuracy was calculated. CRM involvement prediction and the N staging, the accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were assessed for each T stage. The agreement between MRI and histological results was assessed using weighted-kappa statistics. The overall MRI accuracy for T staging was 93.6% (k = 0.85). The accuracy, sensitivity, specificity, PPV and NPV for each T stage were as follows: 91.8%, 86.2%, 95.5%, 92.6% and 91.3% for the group ≤ T2; 90.4%, 94.6%, 86.1%, 87.5% and 94% for T3; 98,6%, 85.7%, 100%, 100% and 98.5% for T4, respectively. The predictive CRM accuracy was 94.5% (k = 0.86); the sensitivity, specificity, PPV and NPV were 89.5%, 96.3%, 89.5%, and 96.3% respectively. The N staging accuracy was 68.49% (k = 0.4). MRI performed with rectal lumen distention has proved to be an effective technique both for rectal cancer staging and involved CRM predicting.

  5. SFOL Pulse: A High Accuracy DME Pulse for Alternative Aircraft Position and Navigation

    Directory of Open Access Journals (Sweden)

    Euiho Kim

    2017-09-01

    Full Text Available In the Federal Aviation Administration’s (FAA performance based navigation strategy announced in 2016, the FAA stated that it would retain and expand the Distance Measuring Equipment (DME infrastructure to ensure resilient aircraft navigation capability during the event of a Global Navigation Satellite System (GNSS outage. However, the main drawback of the DME as a GNSS back up system is that it requires a significant expansion of the current DME ground infrastructure due to its poor distance measuring accuracy over 100 m. The paper introduces a method to improve DME distance measuring accuracy by using a new DME pulse shape. The proposed pulse shape was developed by using Genetic Algorithms and is less susceptible to multipath effects so that the ranging error reduces by 36.0–77.3% when compared to the Gaussian and Smoothed Concave Polygon DME pulses, depending on noise environment.

  6. Automatic J–A Model Parameter Tuning Algorithm for High Accuracy Inrush Current Simulation

    Directory of Open Access Journals (Sweden)

    Xishan Wen

    2017-04-01

    Full Text Available Inrush current simulation plays an important role in many tasks of the power system, such as power transformer protection. However, the accuracy of the inrush current simulation can hardly be ensured. In this paper, a Jiles–Atherton (J–A theory based model is proposed to simulate the inrush current of power transformers. The characteristics of the inrush current curve are analyzed and results show that the entire inrush current curve can be well featured by the crest value of the first two cycles. With comprehensive consideration of both of the features of the inrush current curve and the J–A parameters, an automatic J–A parameter estimation algorithm is proposed. The proposed algorithm can obtain more reasonable J–A parameters, which improve the accuracy of simulation. Experimental results have verified the efficiency of the proposed algorithm.

  7. [Method for evaluating the positional accuracy of a six-degrees-of-freedom radiotherapy couch using high definition digital cameras].

    Science.gov (United States)

    Takemura, Akihiro; Ueda, Shinichi; Noto, Kimiya; Kurata, Yuichi; Shoji, Saori

    2011-01-01

    In this study, we proposed and evaluated a positional accuracy assessment method with two high-resolution digital cameras for add-on six-degrees-of-freedom radiotherapy (6D) couches. Two high resolution digital cameras (D5000, Nikon Co.) were used in this accuracy assessment method. These cameras were placed on two orthogonal axes of a linear accelerator (LINAC) coordinate system and focused on the isocenter of the LINAC. Pictures of a needle that was fixed on the 6D couch were taken by the cameras during couch motions of translation and rotation of each axis. The coordinates of the needle in the pictures were obtained using manual measurement, and the coordinate error of the needle was calculated. The accuracy of a HexaPOD evo (Elekta AB, Sweden) was evaluated using this method. All of the mean values of the X, Y, and Z coordinate errors in the translation tests were within ±0.1 mm. However, the standard deviation of the Z coordinate errors in the Z translation test was 0.24 mm, which is higher than the others. In the X rotation test, we found that the X coordinate of the rotational origin of the 6D couch was shifted. We proposed an accuracy assessment method for a 6D couch. The method was able to evaluate the accuracy of the motion of only the 6D couch and revealed the deviation of the origin of the couch rotation. This accuracy assessment method is effective for evaluating add-on 6D couch positioning.

  8. Thermal Stability of Magnetic Compass Sensor for High Accuracy Positioning Applications

    OpenAIRE

    Van-Tang PHAM; Dinh-Chinh NGUYEN; Quang-Huy TRAN; Duc-Trinh CHU; Duc-Tan TRAN

    2015-01-01

    Using magnetic compass sensors in angle measurements have a wide area of application such as positioning, robot, landslide, etc. However, one of the most phenomenal that affects to the accuracy of the magnetic compass sensor is the temperature. This paper presents two thermal stability schemes for improving performance of a magnetic compass sensor. The first scheme uses the feedforward structure to adjust the angle output of the compass sensor adapt to the variation of the temperature. The se...

  9. A High-Accuracy Linear Conservative Difference Scheme for Rosenau-RLW Equation

    Directory of Open Access Journals (Sweden)

    Jinsong Hu

    2013-01-01

    Full Text Available We study the initial-boundary value problem for Rosenau-RLW equation. We propose a three-level linear finite difference scheme, which has the theoretical accuracy of Oτ2+h4. The scheme simulates two conservative properties of original problem well. The existence, uniqueness of difference solution, and a priori estimates in infinite norm are obtained. Furthermore, we analyze the convergence and stability of the scheme by energy method. At last, numerical experiments demonstrate the theoretical results.

  10. New perspectives for high accuracy SLR with second generation geodesic satellites

    Science.gov (United States)

    Lund, Glenn

    1993-01-01

    This paper reports on the accuracy limitations imposed by geodesic satellite signatures, and on the potential for achieving millimetric performances by means of alternative satellite concepts and an optimized 2-color system tradeoff. Long distance laser ranging, when performed between a ground (emitter/receiver) station and a distant geodesic satellite, is now reputed to enable short arc trajectory determinations to be achieved with an accuracy of 1 to 2 centimeters. This state-of-the-art accuracy is limited principally by the uncertainties inherent to single-color atmospheric path length correction. Motivated by the study of phenomena such as postglacial rebound, and the detailed analysis of small-scale volcanic and strain deformations, the drive towards millimetric accuracies will inevitably be felt. With the advent of short pulse (less than 50 ps) dual wavelength ranging, combined with adequate detection equipment (such as a fast-scanning streak camera or ultra-fast solid-state detectors) the atmospheric uncertainty could potentially be reduced to the level of a few millimeters, thus, exposing other less significant error contributions, of which by far the most significant will then be the morphology of the retroreflector satellites themselves. Existing geodesic satellites are simply dense spheres, several 10's of cm in diameter, encrusted with a large number (426 in the case of LAGEOS) of small cube-corner reflectors. A single incident pulse, thus, results in a significant number of randomly phased, quasi-simultaneous return pulses. These combine coherently at the receiver to produce a convolved interference waveform which cannot, on a shot to shot basis, be accurately and unambiguously correlated to the satellite center of mass. This paper proposes alternative geodesic satellite concepts, based on the use of a very small number of cube-corner retroreflectors, in which the above difficulties are eliminated while ensuring, for a given emitted pulse, the return

  11. A high-accuracy optical linear algebra processor for finite element applications

    Science.gov (United States)

    Casasent, D.; Taylor, B. K.

    1984-01-01

    Optical linear processors are computationally efficient computers for solving matrix-matrix and matrix-vector oriented problems. Optical system errors limit their dynamic range to 30-40 dB, which limits their accuray to 9-12 bits. Large problems, such as the finite element problem in structural mechanics (with tens or hundreds of thousands of variables) which can exploit the speed of optical processors, require the 32 bit accuracy obtainable from digital machines. To obtain this required 32 bit accuracy with an optical processor, the data can be digitally encoded, thereby reducing the dynamic range requirements of the optical system (i.e., decreasing the effect of optical errors on the data) while providing increased accuracy. This report describes a new digitally encoded optical linear algebra processor architecture for solving finite element and banded matrix-vector problems. A linear static plate bending case study is described which quantities the processor requirements. Multiplication by digital convolution is explained, and the digitally encoded optical processor architecture is advanced.

  12. High Accuracy Human Activity Recognition Based on Sparse Locality Preserving Projections.

    Science.gov (United States)

    Zhu, Xiangbin; Qiu, Huiling

    2016-01-01

    Human activity recognition(HAR) from the temporal streams of sensory data has been applied to many fields, such as healthcare services, intelligent environments and cyber security. However, the classification accuracy of most existed methods is not enough in some applications, especially for healthcare services. In order to improving accuracy, it is necessary to develop a novel method which will take full account of the intrinsic sequential characteristics for time-series sensory data. Moreover, each human activity may has correlated feature relationship at different levels. Therefore, in this paper, we propose a three-stage continuous hidden Markov model (TSCHMM) approach to recognize human activities. The proposed method contains coarse, fine and accurate classification. The feature reduction is an important step in classification processing. In this paper, sparse locality preserving projections (SpLPP) is exploited to determine the optimal feature subsets for accurate classification of the stationary-activity data. It can extract more discriminative activities features from the sensor data compared with locality preserving projections. Furthermore, all of the gyro-based features are used for accurate classification of the moving data. Compared with other methods, our method uses significantly less number of features, and the over-all accuracy has been obviously improved.

  13. High Accuracy Human Activity Recognition Based on Sparse Locality Preserving Projections.

    Directory of Open Access Journals (Sweden)

    Xiangbin Zhu

    Full Text Available Human activity recognition(HAR from the temporal streams of sensory data has been applied to many fields, such as healthcare services, intelligent environments and cyber security. However, the classification accuracy of most existed methods is not enough in some applications, especially for healthcare services. In order to improving accuracy, it is necessary to develop a novel method which will take full account of the intrinsic sequential characteristics for time-series sensory data. Moreover, each human activity may has correlated feature relationship at different levels. Therefore, in this paper, we propose a three-stage continuous hidden Markov model (TSCHMM approach to recognize human activities. The proposed method contains coarse, fine and accurate classification. The feature reduction is an important step in classification processing. In this paper, sparse locality preserving projections (SpLPP is exploited to determine the optimal feature subsets for accurate classification of the stationary-activity data. It can extract more discriminative activities features from the sensor data compared with locality preserving projections. Furthermore, all of the gyro-based features are used for accurate classification of the moving data. Compared with other methods, our method uses significantly less number of features, and the over-all accuracy has been obviously improved.

  14. High accuracy microwave frequency measurement based on single-drive dual-parallel Mach-Zehnder modulator

    DEFF Research Database (Denmark)

    Zhao, Ying; Pang, Xiaodan; Deng, Lei

    2011-01-01

    A novel approach for broadband microwave frequency measurement by employing a single-drive dual-parallel Mach-Zehnder modulator is proposed and experimentally demonstrated. Based on bias manipulations of the modulator, conventional frequency-to-power mapping technique is developed by performing a...... 10−3 relative error. This high accuracy frequency measurement technique is a promising candidate for high-speed electronic warfare and defense applications....

  15. THE EFFECT OF MODERATE AND HIGH-INTENSITY FATIGUE ON GROUNDSTROKE ACCURACY IN EXPERT AND NON-EXPERT TENNIS PLAYERS

    Directory of Open Access Journals (Sweden)

    Mark Lyons

    2013-06-01

    Full Text Available Exploring the effects of fatigue on skilled performance in tennis presents a significant challenge to the researcher with respect to ecological validity. This study examined the effects of moderate and high-intensity fatigue on groundstroke accuracy in expert and non-expert tennis players. The research also explored whether the effects of fatigue are the same regardless of gender and player's achievement motivation characteristics. 13 expert (7 male, 6 female and 17 non-expert (13 male, 4 female tennis players participated in the study. Groundstroke accuracy was assessed using the modified Loughborough Tennis Skills Test. Fatigue was induced using the Loughborough Intermittent Tennis Test with moderate (70% and high-intensities (90% set as a percentage of peak heart rate (attained during a tennis-specific maximal hitting sprint test. Ratings of perceived exertion were used as an adjunct to the monitoring of heart rate. Achievement goal indicators for each player were assessed using the 2 x 2 Achievement Goals Questionnaire for Sport in an effort to examine if this personality characteristic provides insight into how players perform under moderate and high-intensity fatigue conditions. A series of mixed ANOVA's revealed significant fatigue effects on groundstroke accuracy regardless of expertise. The expert players however, maintained better groundstroke accuracy across all conditions compared to the novice players. Nevertheless, in both groups, performance following high-intensity fatigue deteriorated compared to performance at rest and performance while moderately fatigued. Groundstroke accuracy under moderate levels of fatigue was equivalent to that at rest. Fatigue effects were also similar regardless of gender. No fatigue by expertise, or fatigue by gender interactions were found. Fatigue effects were also equivalent regardless of player's achievement goal indicators. Future research is required to explore the effects of fatigue on

  16. High accuracy prediction of beta-turns and their types using propensities and multiple alignments.

    Science.gov (United States)

    Fuchs, Patrick F J; Alix, Alain J P

    2005-06-01

    We have developed a method that predicts both the presence and the type of beta-turns, using a straightforward approach based on propensities and multiple alignments. The propensities were calculated classically, but the way to use them for prediction was completely new: starting from a tetrapeptide sequence on which one wants to evaluate the presence of a beta-turn, the propensity for a given residue is modified by taking into account all the residues present in the multiple alignment at this position. The evaluation of a score is then done by weighting these propensities by the use of Position-specific score matrices generated by PSI-BLAST. The introduction of secondary structure information predicted by PSIPRED or SSPRO2 as well as taking into account the flanking residues around the tetrapeptide improved the accuracy greatly. This latter evaluated on a database of 426 reference proteins (previously used on other studies) by a sevenfold crossvalidation gave very good results with a Matthews Correlation Coefficient (MCC) of 0.42 and an overall prediction accuracy of 74.8%; this places our method among the best ones. A jackknife test was also done, which gave results within the same range. This shows that it is possible to reach neural networks accuracy with considerably less computional cost and complexity. Furthermore, propensities remain excellent descriptors of amino acid tendencies to belong to beta-turns, which can be useful for peptide or protein engineering and design. For beta-turn type prediction, we reached the best accuracy ever published in terms of MCC (except for the irregular type IV) in the range of 0.25-0.30 for types I, II, and I' and 0.13-0.15 for types VIII, II', and IV. To our knowledge, our method is the only one available on the Web that predicts types I' and II'. The accuracy evaluated on two larger databases of 547 and 823 proteins was not improved significantly. All of this was implemented into a Web server called COUDES (French acronym

  17. Pion interferometric tests of transport models

    Energy Technology Data Exchange (ETDEWEB)

    Padula, S.S.; Gyulassy, M.; Gavin, S. (Lawrence Berkeley Lab., CA (USA). Nuclear Science Div.)

    1990-01-08

    In hadronic reactions, the usual space-time interpretation of pion interferometry often breaks down due to strong correlations between spatial and momentum coordinates. We derive a general interferometry formula based on the Wigner density formalism that allows for arbitrary phase space and multiparticle correlations. Correction terms due to intermediate state pion cascading are derived using semiclassical hadronic transport theory. Finite wave packets are used to reveal the sensitivity of pion interference effects on the details of the production dynamics. The covariant generalization of the formula is shown to be equivalent to the formula derived via an alternate current ensemble formalism for minimal wave packets and reduces in the nonrelativistic limit to a formula derived by Pratt. The final expression is ideally suited for pion interferometric tests of Monte Carlo transport models. Examples involving gaussian and inside-outside phase space distributions are considered. (orig.).

  18. Pion interferometric tests of transport models

    International Nuclear Information System (INIS)

    Padula, S.S.; Gyulassy, M.; Gavin, S.

    1990-01-01

    In hadronic reactions, the usual space-time interpretation of pion interferometry often breaks down due to strong correlations between spatial and momentum coordinates. We derive a general interferometry formula based on the Wigner density formalism that allows for arbitrary phase space and multiparticle correlations. Correction terms due to intermediate state pion cascading are derived using semiclassical hadronic transport theory. Finite wave packets are used to reveal the sensitivity of pion interference effects on the details of the production dynamics. The covariant generalization of the formula is shown to be equivalent to the formula derived via an alternate current ensemble formalism for minimal wave packets and reduces in the nonrelativistic limit to a formula derived by Pratt. The final expression is ideally suited for pion interferometric tests of Monte Carlo transport models. Examples involving gaussian and inside-outside phase space distributions are considered. (orig.)

  19. Distortion compensation in interferometric testing of mirrors

    International Nuclear Information System (INIS)

    Robinson, Brian M.; Reardon, Patrick J.

    2009-01-01

    We present a method to compensate for the imaging distortion encountered in interferometric testing of mirrors, which is introduced by interferometer optics as well as from geometric projection errors. Our method involves placing a mask, imprinted with a regular square grid, over the mirror and finding a transformation that relates the grid coordinates to coordinates in the base plane of the parent surface. This method can be used on finished mirrors since no fiducials have to be applied to the surfaces. A critical step in the process requires that the grid coordinates be projected onto the mirror base plane before the regression is performed. We apply the method successfully during a center-of-curvature null test of an F/2 off-axis paraboloid

  20. Fundamentals of interferometric gravitational wave detectors

    CERN Document Server

    Saulson, Peter R

    2017-01-01

    LIGO's recent discovery of gravitational waves was headline news around the world. Many people will want to understand more about what a gravitational wave is, how LIGO works, and how LIGO functions as a detector of gravitational waves.This book aims to communicate the basic logic of interferometric gravitational wave detectors to students who are new to the field. It assumes that the reader has a basic knowledge of physics, but no special familiarity with gravitational waves, with general relativity, or with the special techniques of experimental physics. All of the necessary ideas are developed in the book.The first edition was published in 1994. Since the book is aimed at explaining the physical ideas behind the design of LIGO, it stands the test of time. For the second edition, an Epilogue has been added; it brings the treatment of technical details up to date, and provides references that would allow a student to become proficient with today's designs.

  1. The 2014 interferometric imaging beauty contest

    Science.gov (United States)

    Monnier, John D.; Berger, Jean-Philippe; Le Bouquin, Jean-Baptiste; Tuthill, Peter G.; Wittkowski, Markus; Grellmann, Rebekka; Müller, André; Renganswany, Sridhar; Hummel, Christian; Hofmann, Karl-Heinz; Schertl, Dieter; Weigelt, Gerd; Young, John; Buscher, David; Sanchez-Bermudez, Joel; Alberdi, Antxon; Schoedel, Rainer; Köhler, Rainer; Soulez, Ferréol; Thiébaut, Éric; Kluska, Jacques; Malbet, Fabien; Duvert, Gilles; Kraus, Stefan; Kloppenborg, Brian K.; Baron, Fabien; de Wit, Willem-Jan; Rivinius, Thomas; Merand, Antoine

    2014-07-01

    Here we present the results of the 6th biennial optical interferometry imaging beauty contest. Taking advantage of a unique opportunity, the red supergiant VY CMa and the Mira variable R Car were observed in the astronomical H-band with three 4-telescope configurations of the VLTI-AT array using the PIONIER instrument. The community was invited to participate in the subsequent image reconstruction and interpretation phases of the project. Ten groups submitted entries to the beauty contest, and we found reasonable consistency between images obtained from independent workers using quite different algorithms. We also found that significant differences existed between the submitted images, much greater than in past beauty contests that were all based on simulated data. A novel crowd-sourcing" method allowed consensus median images to be constructed, filtering likely artifacts and retaining real features." We definitively detect strong spots on the surfaces of both stars as well as distinct circumstellar shells of emission (likely water/CO) around R Car. In a close contest, Joel Sanchez (IAA-CSIC/Spain) was named the winner of the 2014 interferometric imaging beauty contest. This process has shown that new comers" can use publicly-available imaging software to interpret VLTI/PIONIER imaging data, as long as sufficient observations are taken to have complete uv coverage { a luxury that is often missing. We urge proposers to request adequate observing nights to collect sufficient data for imaging and for time allocation committees to recognise the importance of uv coverage for reliable interpretation of interferometric data. We believe that the result of the proposed broad international project will contribute to inspiring trust in the image reconstruction processes in optical interferometry.

  2. Accuracy of applicator tip reconstruction in MRI-guided interstitial 192Ir-high-dose-rate brachytherapy of liver tumors

    International Nuclear Information System (INIS)

    Wybranski, Christian; Eberhardt, Benjamin; Fischbach, Katharina; Fischbach, Frank; Walke, Mathias; Hass, Peter; Röhl, Friedrich-Wilhelm; Kosiek, Ortrud; Kaiser, Mandy; Pech, Maciej; Lüdemann, Lutz; Ricke, Jens

    2015-01-01

    Background and purpose: To evaluate the reconstruction accuracy of brachytherapy (BT) applicators tips in vitro and in vivo in MRI-guided 192 Ir-high-dose-rate (HDR)-BT of inoperable liver tumors. Materials and methods: Reconstruction accuracy of plastic BT applicators, visualized by nitinol inserts, was assessed in MRI phantom measurements and in MRI 192 Ir-HDR-BT treatment planning datasets of 45 patients employing CT co-registration and vector decomposition. Conspicuity, short-term dislocation, and reconstruction errors were assessed in the clinical data. The clinical effect of applicator reconstruction accuracy was determined in follow-up MRI data. Results: Applicator reconstruction accuracy was 1.6 ± 0.5 mm in the phantom measurements. In the clinical MRI datasets applicator conspicuity was rated good/optimal in ⩾72% of cases. 16/129 applicators showed not time dependent deviation in between MRI/CT acquisition (p > 0.1). Reconstruction accuracy was 5.5 ± 2.8 mm, and the average image co-registration error was 3.1 ± 0.9 mm. Vector decomposition revealed no preferred direction of reconstruction errors. In the follow-up data deviation of planned dose distribution and irradiation effect was 6.9 ± 3.3 mm matching the mean co-registration error (6.5 ± 2.5 mm; p > 0.1). Conclusion: Applicator reconstruction accuracy in vitro conforms to AAPM TG 56 standard. Nitinol-inserts are feasible for applicator visualization and yield good conspicuity in MRI treatment planning data. No preferred direction of reconstruction errors were found in vivo

  3. Horizontal Positional Accuracy of Google Earth’s High-Resolution Imagery Archive

    Directory of Open Access Journals (Sweden)

    David Potere

    2008-12-01

    Full Text Available Google Earth now hosts high-resolution imagery that spans twenty percent of the Earth’s landmass and more than a third of the human population. This contemporary highresolution archive represents a significant, rapidly expanding, cost-free and largely unexploited resource for scientific inquiry. To increase the scientific utility of this archive, we address horizontal positional accuracy (georegistration by comparing Google Earth with Landsat GeoCover scenes over a global sample of 436 control points located in 109 cities worldwide. Landsat GeoCover is an orthorectified product with known absolute positional accuracy of less than 50 meters root-mean-squared error (RMSE. Relative to Landsat GeoCover, the 436 Google Earth control points have a positional accuracy of 39.7 meters RMSE (error magnitudes range from 0.4 to 171.6 meters. The control points derived from satellite imagery have an accuracy of 22.8 meters RMSE, which is significantly more accurate than the 48 control-points based on aerial photography (41.3 meters RMSE; t-test p-value < 0.01. The accuracy of control points in more-developed countries is 24.1 meters RMSE, which is significantly more accurate than the control points in developing countries (44.4 meters RMSE; t-test p-value < 0.01. These findings indicate that Google Earth highresolution imagery has a horizontal positional accuracy that is sufficient for assessing moderate-resolution remote sensing products across most of the world’s peri-urban areas.

  4. High accuracy mapping with cartographic assessment for a fixed-wing remotely piloted aircraft system

    Science.gov (United States)

    Alves Júnior, Leomar Rufino; Ferreira, Manuel Eduardo; Côrtes, João Batista Ramos; de Castro Jorge, Lúcio André

    2018-01-01

    The lack of updated maps on large scale representations has encouraged the use of remotely piloted aircraft systems (RPAS) to generate maps for a wide range of professionals. However, some questions arise: do the orthomosaics generated by these systems have the cartographic precision required to use them? Which problems can be identified in stitching orthophotos to generate orthomosaics? To answer these questions, an aerophotogrammetric survey was conducted in an environmental conservation unit in the city of Goiânia. The flight plan was set up using the E-motion software, provided by Sensefly-a Swiss manufacturer of the RPAS Swinglet CAM used in this work. The camera installed in the RPAS was the Canon IXUS 220 HS, with the number of pixels in the sensor array of 12.1 megapixel, complementary metal oxide semiconductor 1 ∶ 2.3 ? (4000 × 3000 pixel), horizontal and vertical pixel sizes of 1.54 μm. Using the orthophotos, four orthomosaics were generated in the Pix4D mapper software. The first orthomosaic was generated without using the control points. The other three mosaics were generated using 4, 8, and 16 premarked ground control points. To check the precision and accuracy of the orthomosaics, 46 premarked targets were uniformly distributed in the block. The three-dimensional (3-D) coordinates of the premarked targets were read on the orthomosaic and compared with the coordinates obtained by the geodetic survey real-time kinematic positioning method using the global navigation satellite system receiver signals. The cartographic accuracy standard was evaluated by discrepancies between these coordinates. The bias was analyzed by the Student's t test and the accuracy by the chi-square probability considering the orthomosaic on a scale of 1 ∶ 250, in which 90% of the points tested must have a planimetric error of control points the scale was 10-fold smaller (1 ∶ 3000).

  5. High-accuracy resolver-to-digital conversion via phase locked loop based on PID controller

    Science.gov (United States)

    Li, Yaoling; Wu, Zhong

    2018-03-01

    The problem of resolver-to-digital conversion (RDC) is transformed into the problem of angle tracking control, and a phase locked loop (PLL) method based on PID controller is proposed in this paper. This controller comprises a typical PI controller plus an incomplete differential which can avoid the amplification of higher-frequency noise components by filtering the phase detection error with a low-pass filter. Compared with conventional ones, the proposed PLL method makes the converter a system of type III and thus the conversion accuracy can be improved. Experimental results demonstrate the effectiveness of the proposed method.

  6. KLEIN: Coulomb functions for real lambda and positive energy to high accuracy

    International Nuclear Information System (INIS)

    Barnett, A.R.

    1981-01-01

    KLEIN computes relativistic Schroedinger (Klein-Gordon) equation solutions, i.e. Coulomb functions for real lambda > - 1, Fsub(lambda)(eta,x), Gsub(lambda)(eta,x), F'sub(lambda)(eta,x) and G'sub(lambda)(eta,x) for real kappa > 0 and real eta, - 10 4 4 . Hence it is also suitable for Bessel and spherical Bessel functions. Accuracies are in the range 10 -14 -10 -16 in oscillating region, and approx. equal to 10 -30 on an extended precision compiler. The program is suitable for generating Klein-Gordon wavefunctions for matching in pion and kaon physics. (orig.)

  7. Depth extraction method with high accuracy in integral imaging based on moving array lenslet technique

    Science.gov (United States)

    Wang, Yao-yao; Zhang, Juan; Zhao, Xue-wei; Song, Li-pei; Zhang, Bo; Zhao, Xing

    2018-03-01

    In order to improve depth extraction accuracy, a method using moving array lenslet technique (MALT) in pickup stage is proposed, which can decrease the depth interval caused by pixelation. In this method, the lenslet array is moved along the horizontal and vertical directions simultaneously for N times in a pitch to get N sets of elemental images. Computational integral imaging reconstruction method for MALT is taken to obtain the slice images of the 3D scene, and the sum modulus (SMD) blur metric is taken on these slice images to achieve the depth information of the 3D scene. Simulation and optical experiments are carried out to verify the feasibility of this method.

  8. Cause and Cure - Deterioration in Accuracy of CFD Simulations With Use of High-Aspect-Ratio Triangular Tetrahedral Grids

    Science.gov (United States)

    Chang, Sin-Chung; Chang, Chau-Lyan; Venkatachari, Balaji Shankar

    2017-01-01

    Traditionally high-aspect ratio triangular/tetrahedral meshes are avoided by CFD re-searchers in the vicinity of a solid wall, as it is known to reduce the accuracy of gradient computations in those regions and also cause numerical instability. Although for certain complex geometries, the use of high-aspect ratio triangular/tetrahedral elements in the vicinity of a solid wall can be replaced by quadrilateral/prismatic elements, ability to use triangular/tetrahedral elements in such regions without any degradation in accuracy can be beneficial from a mesh generation point of view. The benefits also carry over to numerical frameworks such as the space-time conservation element and solution element (CESE), where triangular/tetrahedral elements are the mandatory building blocks. With the requirement of the CESE method in mind, a rigorous mathematical framework that clearly identities the reason behind the difficulties in use of such high-aspect ratio triangular/tetrahedral elements is presented here. As will be shown, it turns out that the degree of accuracy deterioration of gradient computation involving a triangular element is hinged on the value of its shape factor Gamma def = sq sin Alpha1 + sq sin Alpha2 + sq sin Alpha3, where Alpha1; Alpha2 and Alpha3 are the internal angles of the element. In fact, it is shown that the degree of accuracy deterioration increases monotonically as the value of Gamma decreases monotonically from its maximal value 9/4 (attained by an equilateral triangle only) to a value much less than 1 (associated with a highly obtuse triangle). By taking advantage of the fact that a high-aspect ratio triangle is not necessarily highly obtuse, and in fact it can have a shape factor whose value is close to the maximal value 9/4, a potential solution to avoid accuracy deterioration of gradient computation associated with a high-aspect ratio triangular grid is given. Also a brief discussion on the extension of the current mathematical framework to the

  9. Affine-Invariant Geometric Constraints-Based High Accuracy Simultaneous Localization and Mapping

    Directory of Open Access Journals (Sweden)

    Gangchen Hua

    2017-01-01

    Full Text Available In this study we describe a new appearance-based loop-closure detection method for online incremental simultaneous localization and mapping (SLAM using affine-invariant-based geometric constraints. Unlike other pure bag-of-words-based approaches, our proposed method uses geometric constraints as a supplement to improve accuracy. By establishing an affine-invariant hypothesis, the proposed method excludes incorrect visual words and calculates the dispersion of correctly matched visual words to improve the accuracy of the likelihood calculation. In addition, camera’s intrinsic parameters and distortion coefficients are adequate for this method. 3D measuring is not necessary. We use the mechanism of Long-Term Memory and Working Memory (WM to manage the memory. Only a limited size of the WM is used for loop-closure detection; therefore the proposed method is suitable for large-scale real-time SLAM. We tested our method using the CityCenter and Lip6Indoor datasets. Our proposed method results can effectively correct the typical false-positive localization of previous methods, thus gaining better recall ratios and better precision.

  10. The use of high accuracy NAA for the certification of NIST Standard Reference Materials

    International Nuclear Information System (INIS)

    Becker, D.A.; Greenberg, R.R.; Stone, S.

    1991-01-01

    Neutron activation analysis (NAA) is only one of many analytical techniques used at the National Institute of Standards and Technology (NIST) for the certification of NIST Standard Reference Materials (SRMs). We compete daily against all of the other available analytical techniques in terms of accuracy, precision, and the cost required to obtain that requisite accuracy and precision. Over the years, the authors have found that NAA can and does compete favorably with these other techniques because of its' unique capabilities for redundancy and quality assurance. Good examples are the two new NIST leaf SRMs, Apple Leaves (SRM 1515) and Peach Leaves (SRM 1547). INAA was used to measure the homogeneity of 12 elements in 15 samples of each material at the 100 mg sample size. In addition, instrumental and radiochemical NAA combined for 27 elemental determinations, out of a total of 54 elemental determinations made on each material with all NIST techniques combined. This paper describes the NIST NAA procedures used in these analyses, the quality assurance techniques employed, and the analytical results for the 24 elements determined by NAA in these new botanical SRMs. The NAA results are also compared to the final certified values for these SRMs

  11. High-accuracy 3-D modeling of cultural heritage: the digitizing of Donatello's "Maddalena".

    Science.gov (United States)

    Guidi, Gabriele; Beraldin, J Angelo; Atzeni, Carlo

    2004-03-01

    Three-dimensional digital modeling of Heritage works of art through optical scanners, has been demonstrated in recent years with results of exceptional interest. However, the routine application of three-dimensional (3-D) modeling to Heritage conservation still requires the systematic investigation of a number of technical problems. In this paper, the acquisition process of the 3-D digital model of the Maddalena by Donatello, a wooden statue representing one of the major masterpieces of the Italian Renaissance which was swept away by the Florence flood of 1966 and successively restored, is described. The paper reports all the steps of the acquisition procedure, from the project planning to the solution of the various problems due to range camera calibration and to material non optically cooperative. Since the scientific focus is centered on the 3-D model overall dimensional accuracy, a methodology for its quality control is described. Such control has demonstrated how, in some situations, the ICP-based alignment can lead to incorrect results. To circumvent this difficulty we propose an alignment technique based on the fusion of ICP with close-range digital photogrammetry and a non-invasive procedure in order to generate a final accurate model. In the end detailed results are presented, demonstrating the improvement of the final model, and how the proposed sensor fusion ensure a pre-specified level of accuracy.

  12. Vision-based algorithms for high-accuracy measurements in an industrial bakery

    Science.gov (United States)

    Heleno, Paulo; Davies, Roger; Correia, Bento A. B.; Dinis, Joao

    2002-02-01

    This paper describes the machine vision algorithms developed for VIP3D, a measuring system used in an industrial bakery to monitor the dimensions and weight of loaves of bread (baguettes). The length and perimeter of more than 70 different varieties of baguette are measured with 1-mm accuracy, quickly, reliably and automatically. VIP3D uses a laser triangulation technique to measure the perimeter. The shape of the loaves is approximately cylindrical and the perimeter is defined as the convex hull of a cross-section perpendicular to the baguette axis at mid-length. A camera, mounted obliquely to the measuring plane, captures an image of a laser line projected onto the upper surface of the baguette. Three cameras are used to measure the baguette length, a solution adopted in order to minimize perspective-induced measurement errors. The paper describes in detail the machine vision algorithms developed to perform segmentation of the laser line and subsequent calculation of the perimeter of the baguette. The algorithms used to segment and measure the position of the ends of the baguette, to sub-pixel accuracy, are also described, as are the algorithms used to calibrate the measuring system and compensate for camera-induced image distortion.

  13. Interobserver Variability and Accuracy of High-Definition Endoscopic Diagnosis for Gastric Intestinal Metaplasia among Experienced and Inexperienced Endoscopists

    Science.gov (United States)

    Hyun, Yil Sik; Bae, Joong Ho; Park, Hye Sun; Eun, Chang Soo

    2013-01-01

    Accurate diagnosis of gastric intestinal metaplasia is important; however, conventional endoscopy is known to be an unreliable modality for diagnosing gastric intestinal metaplasia (IM). The aims of the study were to evaluate the interobserver variation in diagnosing IM by high-definition (HD) endoscopy and the diagnostic accuracy of this modality for IM among experienced and inexperienced endoscopists. Selected 50 cases, taken with HD endoscopy, were sent for a diagnostic inquiry of gastric IM through visual inspection to five experienced and five inexperienced endoscopists. The interobserver agreement between endoscopists was evaluated to verify the diagnostic reliability of HD endoscopy in diagnosing IM, and the diagnostic accuracy, sensitivity, and specificity were evaluated for validity of HD endoscopy in diagnosing IM. Interobserver agreement among the experienced endoscopists was "poor" (κ = 0.38) and it was also "poor" (κ = 0.33) among the inexperienced endoscopists. The diagnostic accuracy of the experienced endoscopists was superior to that of the inexperienced endoscopists (P = 0.003). Since diagnosis through visual inspection is unreliable in the diagnosis of IM, all suspicious areas for gastric IM should be considered to be biopsied. Furthermore, endoscopic experience and education are needed to raise the diagnostic accuracy of gastric IM. PMID:23678267

  14. Interobserver variability and accuracy of high-definition endoscopic diagnosis for gastric intestinal metaplasia among experienced and inexperienced endoscopists.

    Science.gov (United States)

    Hyun, Yil Sik; Han, Dong Soo; Bae, Joong Ho; Park, Hye Sun; Eun, Chang Soo

    2013-05-01

    Accurate diagnosis of gastric intestinal metaplasia is important; however, conventional endoscopy is known to be an unreliable modality for diagnosing gastric intestinal metaplasia (IM). The aims of the study were to evaluate the interobserver variation in diagnosing IM by high-definition (HD) endoscopy and the diagnostic accuracy of this modality for IM among experienced and inexperienced endoscopists. Selected 50 cases, taken with HD endoscopy, were sent for a diagnostic inquiry of gastric IM through visual inspection to five experienced and five inexperienced endoscopists. The interobserver agreement between endoscopists was evaluated to verify the diagnostic reliability of HD endoscopy in diagnosing IM, and the diagnostic accuracy, sensitivity, and specificity were evaluated for validity of HD endoscopy in diagnosing IM. Interobserver agreement among the experienced endoscopists was "poor" (κ = 0.38) and it was also "poor" (κ = 0.33) among the inexperienced endoscopists. The diagnostic accuracy of the experienced endoscopists was superior to that of the inexperienced endoscopists (P = 0.003). Since diagnosis through visual inspection is unreliable in the diagnosis of IM, all suspicious areas for gastric IM should be considered to be biopsied. Furthermore, endoscopic experience and education are needed to raise the diagnostic accuracy of gastric IM.

  15. Thermal Stability of Magnetic Compass Sensor for High Accuracy Positioning Applications

    Directory of Open Access Journals (Sweden)

    Van-Tang PHAM

    2015-12-01

    Full Text Available Using magnetic compass sensors in angle measurements have a wide area of application such as positioning, robot, landslide, etc. However, one of the most phenomenal that affects to the accuracy of the magnetic compass sensor is the temperature. This paper presents two thermal stability schemes for improving performance of a magnetic compass sensor. The first scheme uses the feedforward structure to adjust the angle output of the compass sensor adapt to the variation of the temperature. The second scheme increases both the temperature working range and steady error performance of the sensor. In this scheme, we try to keep the temperature of the sensor is stable at the certain value (e.g. 25 oC by using a PID (proportional-integral-derivative controller and a heating/cooling generator. Many experiment scenarios have implemented to confirm the effectivity of these solutions.

  16. Hyperbolic Method for Dispersive PDEs: Same High-Order of Accuracy for Solution, Gradient, and Hessian

    Science.gov (United States)

    Mazaheri, Alireza; Ricchiuto, Mario; Nishikawa, Hiroaki

    2016-01-01

    In this paper, we introduce a new hyperbolic first-order system for general dispersive partial differential equations (PDEs). We then extend the proposed system to general advection-diffusion-dispersion PDEs. We apply the fourth-order RD scheme of Ref. 1 to the proposed hyperbolic system, and solve time-dependent dispersive equations, including the classical two-soliton KdV and a dispersive shock case. We demonstrate that the predicted results, including the gradient and Hessian (second derivative), are in a very good agreement with the exact solutions. We then show that the RD scheme applied to the proposed system accurately captures dispersive shocks without numerical oscillations. We also verify that the solution, gradient and Hessian are predicted with equal order of accuracy.

  17. High-accuracy energy formulas for the attractive two-site Bose-Hubbard model

    Science.gov (United States)

    Ermakov, Igor; Byrnes, Tim; Bogoliubov, Nikolay

    2018-02-01

    The attractive two-site Bose-Hubbard model is studied within the framework of the analytical solution obtained by the application of the quantum inverse scattering method. The structure of the ground and excited states is analyzed in terms of solutions of Bethe equations, and an approximate solution for the Bethe roots is given. This yields approximate formulas for the ground-state energy and for the first excited-state energy. The obtained formulas work with remarkable precision for a wide range of parameters of the model, and are confirmed numerically. An expansion of the Bethe state vectors into a Fock space is also provided for evaluation of expectation values, although this does not have accuracy similar to that of the energies.

  18. Accuracy and repeatability positioning of high-performancel athe for non-circular turning

    Directory of Open Access Journals (Sweden)

    Majda Paweł

    2017-11-01

    Full Text Available This paper presents research on the accuracy and repeatability of CNC axis positioning in an innovative lathe with an additional Xs axis. This axis is used to perform movements synchronized with the angular position of the main drive, i.e. the spindle, and with the axial feed along the Z axis. This enables the one-pass turning of non-circular surfaces, rope and trapezoidal threads, as well as the surfaces of rotary tools such as a gear cutting hob, etc. The paper presents and discusses the interpretation of results and the calibration effects of positioning errors in the lathe’s numerical control system. Finally, it shows the geometric characteristics of the rope thread turned at various spindle speeds, including before and after-correction of the positioning error of the Xs axis.

  19. Accuracy and repeatability positioning of high-performancel athe for non-circular turning

    Science.gov (United States)

    Majda, Paweł; Powałka, Bartosz

    2017-11-01

    This paper presents research on the accuracy and repeatability of CNC axis positioning in an innovative lathe with an additional Xs axis. This axis is used to perform movements synchronized with the angular position of the main drive, i.e. the spindle, and with the axial feed along the Z axis. This enables the one-pass turning of non-circular surfaces, rope and trapezoidal threads, as well as the surfaces of rotary tools such as a gear cutting hob, etc. The paper presents and discusses the interpretation of results and the calibration effects of positioning errors in the lathe's numerical control system. Finally, it shows the geometric characteristics of the rope thread turned at various spindle speeds, including before and after-correction of the positioning error of the Xs axis.

  20. A method of high accuracy clock synchronization by frequency following with VCXO

    International Nuclear Information System (INIS)

    Ma Yichao; Wu Jie; Zhang Jie; Song Hongzhi; Kong Yang

    2011-01-01

    In this paper, the principle of the synchronous protocol of the IEEE1588 is analyzed, and the factors that affect the accuracy of synchronization is summarized. Through the hardware timer in a microcontroller, we give the exactly the time when a package is sent or received. So synchronization of the distributed clocks can reach 1 μs in this way. Another method to improve precision of the synchronization is to replace the traditional fixed frequency crystal of the slave device, which needs to follow up the master clock, by an adjustable VCXO. So it is possible to fine tune the frequency of the distributed clocks, and reduce the drift of clock, which shows great benefit for the clock synchronization. A test measurement shows the synchronization of distribute clocks can be better than 10 ns using this method, which is more accurate than the method realized by software. (authors)

  1. Advancements in the Interferometric Measurements of Real Time Finishing Birefringent Filter's Crystal Plates

    International Nuclear Information System (INIS)

    Gan, Ma; Kushtal, Gi; Skomorovsky, Vi; Domyshev, Gn; Sadokhin, Vp

    2006-01-01

    The finishing of birefringent plates consists of two processes: polishing and evaluation of a surface, which have been performed separately till now. The purpose of this work is achieving of high accuracy of the evaluation and machining of the plane-parallel plates from birefringent crystals, in particular of crystal plates of birefringent filters during their finishing. The developed process combines evaluation and polishing in an interactive way. We have found modes of treatment, shape of polisher, have designed interferometer, with a mirror arranged in polisher. Visual checking of optical thickness comparatively with reference plate was carried out using the interference fringes of equal birefringence, and checking of an optical wedge - by interference rings of an equal inclination. The automated processing of TV camera interference fringes was impossible, because of gaps of interference fringes on polishing cells above the mirror. Therefore a special software was developed for processing of a complex fringe pattern interferogram. Software FastInterf uses furrier analysis technique which allows to process an interferogram with multiply gaps. Interferograms are registered by a high resolution TV camera (1280 x1024). Automatic processing of a fringe interferogram using FastInterf software takes less then one second. The influence of gaps is excluded, and the flat field is taken into account. Software provides full 3D surface and wavefront maps. Aberration analysis of a wavefront gives information on thickness of a plate comparatively with a reference one, optical wedge of plate and azimuth of an inclination of wave front. Moreover, software provides a control of surface quality. The measuring device, features of the software are described and process of interferometric evaluation during polishing is illustrated

  2. Advancements in the Interferometric Measurements of Real Time Finishing Birefringent Filter's Crystal Plates

    Energy Technology Data Exchange (ETDEWEB)

    Gan, Ma [State Optical Institute, Birzhevaya linia, 12 St. Petersburg (Russian Federation); Kushtal, Gi; Skomorovsky, Vi; Domyshev, Gn; Sadokhin, Vp [Institute of Solar-Terrestrial Physics Siberian Branch of Russian Academy of Sciences, 126 Lermontova Str., PO 4026, 664033, Irkutsk (Russian Federation)

    2006-10-15

    The finishing of birefringent plates consists of two processes: polishing and evaluation of a surface, which have been performed separately till now. The purpose of this work is achieving of high accuracy of the evaluation and machining of the plane-parallel plates from birefringent crystals, in particular of crystal plates of birefringent filters during their finishing. The developed process combines evaluation and polishing in an interactive way. We have found modes of treatment, shape of polisher, have designed interferometer, with a mirror arranged in polisher. Visual checking of optical thickness comparatively with reference plate was carried out using the interference fringes of equal birefringence, and checking of an optical wedge - by interference rings of an equal inclination. The automated processing of TV camera interference fringes was impossible, because of gaps of interference fringes on polishing cells above the mirror. Therefore a special software was developed for processing of a complex fringe pattern interferogram. Software FastInterf uses furrier analysis technique which allows to process an interferogram with multiply gaps. Interferograms are registered by a high resolution TV camera (1280 x1024). Automatic processing of a fringe interferogram using FastInterf software takes less then one second. The influence of gaps is excluded, and the flat field is taken into account. Software provides full 3D surface and wavefront maps. Aberration analysis of a wavefront gives information on thickness of a plate comparatively with a reference one, optical wedge of plate and azimuth of an inclination of wave front. Moreover, software provides a control of surface quality. The measuring device, features of the software are described and process of interferometric evaluation during polishing is illustrated.

  3. STTR Phase I: Low-Cost, High-Accuracy, Whole-Building Carbon Dioxide Monitoring for Demand Control Ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Hallstrom, Jason; Ni, Zheng Richard

    2018-05-15

    This STTR Phase I project assessed the feasibility of a new CO2 sensing system optimized for low-cost, high-accuracy, whole-building monitoring for use in demand control ventilation. The focus was on the development of a wireless networking platform and associated firmware to provide signal conditioning and conversion, fault- and disruptiontolerant networking, and multi-hop routing at building scales to avoid wiring costs. Early exploration of a bridge (or “gateway”) to direct digital control services was also explored. Results of the project contributed to an improved understanding of a new electrochemical sensor for monitoring indoor CO2 concentrations, as well as the electronics and networking infrastructure required to deploy those sensors at building scales. New knowledge was acquired concerning the sensor’s accuracy, environmental response, and failure modes, and the acquisition electronics required to achieve accuracy over a wide range of CO2 concentrations. The project demonstrated that the new sensor offers repeatable correspondence with commercial optical sensors, with supporting electronics that offer gain accuracy within 0.5%, and acquisition accuracy within 1.5% across three orders of magnitude variation in generated current. Considering production, installation, and maintenance costs, the technology presents a foundation for achieving whole-building CO2 sensing at a price point below $0.066 / sq-ft – meeting economic feasibility criteria established by the Department of Energy. The technology developed under this award addresses obstacles on the critical path to enabling whole-building CO2 sensing and demand control ventilation in commercial retrofits, small commercial buildings, residential complexes, and other highpotential structures that have been slow to adopt these technologies. It presents an opportunity to significantly reduce energy use throughout the United States a

  4. Benefits and limitations of imaging multiples: Interferometric and resonant migration

    KAUST Repository

    Guo, Bowen; Yu, Jianhua; Huang, Yunsong; Hanafy, Sherif M.; Schuster, Gerard T.

    2015-01-01

    The benefits and limitations of imaging multiples are reviewed for interferometric migration and resonant migration. Synthetic and field data examples are used to characterize the effectiveness of the methods.

  5. Interferometric full-waveform inversion of time-lapse data

    KAUST Repository

    Sinha, Mrinal

    2017-01-01

    surveys. To overcome this challenge, we propose the use of interferometric full waveform inversion (IFWI) for inverting the velocity model from data recorded by baseline and monitor surveys. A known reflector is used as the reference reflector for IFWI

  6. Benefits and limitations of imaging multiples: Interferometric and resonant migration

    KAUST Repository

    Guo, Bowen

    2015-07-01

    The benefits and limitations of imaging multiples are reviewed for interferometric migration and resonant migration. Synthetic and field data examples are used to characterize the effectiveness of the methods.

  7. SPECTROSCOPIC AND INTERFEROMETRIC MEASUREMENTS OF NINE K GIANT STARS

    Energy Technology Data Exchange (ETDEWEB)

    Baines, Ellyn K. [Remote Sensing Division, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Döllinger, Michaela P. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Guenther, Eike W.; Hatzes, Artie P. [Thüringer Landessternwarte Tautenburg, Sternwarte 5, D-07778 Tautenburg (Germany); Hrudkovu, Marie [Isaac Newton Group of Telescopes, Apartado de Correos 321, E-387 00 Santa Cruz de la Palma, Canary Islands (Spain); Belle, Gerard T. van, E-mail: ellyn.baines@nrl.navy.mil [Lowell Observatory, Flagstaff, AZ 86001 (United States)

    2016-09-01

    We present spectroscopic and interferometric measurements for a sample of nine K giant stars. These targets are of particular interest because they are slated for stellar oscillation observations. Our improved parameters will directly translate into reduced errors in the final masses for these stars when interferometric radii and asteroseismic densities are combined. Here, we determine each star’s limb-darkened angular diameter, physical radius, luminosity, bolometric flux, effective temperature, surface gravity, metallicity, and mass. When we compare our interferometric and spectroscopic results, we find no systematic offsets in the diameters and the values generally agree within the errors. Our interferometric temperatures for seven of the nine stars are hotter than those determined from spectroscopy with an average difference of about 380 K.

  8. High-accuracy CFD prediction methods for fluid and structure temperature fluctuations at T-junction for thermal fatigue evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Shaoxiang, E-mail: qian.shaoxiang@jgc.com [EN Technology Center, Process Technology Division, JGC Corporation, 2-3-1 Minato Mirai, Nishi-ku, Yokohama 220-6001 (Japan); Kanamaru, Shinichiro [EN Technology Center, Process Technology Division, JGC Corporation, 2-3-1 Minato Mirai, Nishi-ku, Yokohama 220-6001 (Japan); Kasahara, Naoto [Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2015-07-15

    Highlights: • Numerical methods for accurate prediction of thermal loading were proposed. • Predicted fluid temperature fluctuation (FTF) intensity is close to the experiment. • Predicted structure temperature fluctuation (STF) range is close to the experiment. • Predicted peak frequencies of FTF and STF also agree well with the experiment. • CFD results show the proposed numerical methods are of sufficiently high accuracy. - Abstract: Temperature fluctuations generated by the mixing of hot and cold fluids at a T-junction, which is widely used in nuclear power and process plants, can cause thermal fatigue failure. The conventional methods for evaluating thermal fatigue tend to provide insufficient accuracy, because they were developed based on limited experimental data and a simplified one-dimensional finite element analysis (FEA). CFD/FEA coupling analysis is expected as a useful tool for the more accurate evaluation of thermal fatigue. The present paper aims to verify the accuracy of proposed numerical methods of simulating fluid and structure temperature fluctuations at a T-junction for thermal fatigue evaluation. The dynamic Smagorinsky model (DSM) is used for large eddy simulation (LES) sub-grid scale (SGS) turbulence model, and a hybrid scheme (HS) is adopted for the calculation of convective terms in the governing equations. Also, heat transfer between fluid and structure is calculated directly through thermal conduction by creating a mesh with near wall resolution (NWR) by allocating grid points within the thermal boundary sub-layer. The simulation results show that the distribution of fluid temperature fluctuation intensity and the range of structure temperature fluctuation are remarkably close to the experimental results. Moreover, the peak frequencies of power spectrum density (PSD) of both fluid and structure temperature fluctuations also agree well with the experimental results. Therefore, the numerical methods used in the present paper are

  9. Interferometric crosstalk suppression using polarization multiplexing technique and an SOA

    DEFF Research Database (Denmark)

    Liu, Fenghai; Xueyan, Zheng; Pedersen, Rune Johan Skullerud

    2000-01-01

    Interferometric crosstalk can be greatly suppressed at 10Gb/s and 20Gb/s by using a gain saturated SOA and a polarization multiplexing technique that eliminates impairments like waveform and extinction ratio degradation from the SOA.......Interferometric crosstalk can be greatly suppressed at 10Gb/s and 20Gb/s by using a gain saturated SOA and a polarization multiplexing technique that eliminates impairments like waveform and extinction ratio degradation from the SOA....

  10. Radiometric inter-sensor cross-calibration uncertainty using a traceable high accuracy reference hyperspectral imager

    Science.gov (United States)

    Gorroño, Javier; Banks, Andrew C.; Fox, Nigel P.; Underwood, Craig

    2017-08-01

    Optical earth observation (EO) satellite sensors generally suffer from drifts and biases relative to their pre-launch calibration, caused by launch and/or time in the space environment. This places a severe limitation on the fundamental reliability and accuracy that can be assigned to satellite derived information, and is particularly critical for long time base studies for climate change and enabling interoperability and Analysis Ready Data. The proposed TRUTHS (Traceable Radiometry Underpinning Terrestrial and Helio-Studies) mission is explicitly designed to address this issue through re-calibrating itself directly to a primary standard of the international system of units (SI) in-orbit and then through the extension of this SI-traceability to other sensors through in-flight cross-calibration using a selection of Committee on Earth Observation Satellites (CEOS) recommended test sites. Where the characteristics of the sensor under test allows, this will result in a significant improvement in accuracy. This paper describes a set of tools, algorithms and methodologies that have been developed and used in order to estimate the radiometric uncertainty achievable for an indicative target sensor through in-flight cross-calibration using a well-calibrated hyperspectral SI-traceable reference sensor with observational characteristics such as TRUTHS. In this study, Multi-Spectral Imager (MSI) of Sentinel-2 and Landsat-8 Operational Land Imager (OLI) is evaluated as an example, however the analysis is readily translatable to larger-footprint sensors such as Sentinel-3 Ocean and Land Colour Instrument (OLCI) and Visible Infrared Imaging Radiometer Suite (VIIRS). This study considers the criticality of the instrumental and observational characteristics on pixel level reflectance factors, within a defined spatial region of interest (ROI) within the target site. It quantifies the main uncertainty contributors in the spectral, spatial, and temporal domains. The resultant tool

  11. A Comparison of Acoustic Field Measurement by a Microphone and by an Optical Interferometric Probe

    Directory of Open Access Journals (Sweden)

    R. Bálek

    2002-01-01

    Full Text Available The objective of this work is to show that our optical method for measuring acoustic pressure is in some way superior to measurement using a microphone. Measurement of the integral acoustic pressure in the air by a laser interferometric probe is compared with measurement using a microphone. We determined the particular harmonic components in the acoustic field in the case of relatively high acoustic power in the ultrasonic frequency range.

  12. Application of holographic interferometric studies of underwater shock-wave focusing to medicine

    Science.gov (United States)

    Takayama, Kazuyoshi; Nagoya, H.; Obara, Tetsuro; Kuwahara, M.

    1993-01-01

    Holographic interferometric flow visualization was successfully applied to underwater shock wave focusing and its application to extracorporeal shock wave lithotripsy (ESWL). Real time diffuse holograms revealed the shock wave focusing process in an ellipsoidal reflector made from PMMA and double exposure holographic interferometry also clarified quantitatively the shock focusing process. Disintegration of urinary tract stones and gallbladder stones was observed by high speed photogrammetry. Tissue damage associated with the ESWL treatment is discussed in some detail.

  13. Dynamic spectro-polarimeter based on a modified Michelson interferometric scheme.

    Science.gov (United States)

    Dembele, Vamara; Jin, Moonseob; Baek, Byung-Joon; Kim, Daesuk

    2016-06-27

    A simple dynamic spectro-polarimeter based on a modified Michelson interferometric scheme is described. The proposed system can extract a spectral Stokes vector of a transmissive anisotropic object. Detail theoretical background is derived and experiments are conducted to verify the feasibility of the proposed novel snapshot spectro-polarimeter. The proposed dynamic spectro-polarimeter enables us to extract highly accurate spectral Stokes vector of any transmissive anisotropic object with a frame rate of more than 20Hz.

  14. The high accuracy data processing system of laser interferometry signals based on MSP430

    Science.gov (United States)

    Qi, Yong-yue; Lin, Yu-chi; Zhao, Mei-rong

    2009-07-01

    Generally speaking there are two orthogonal signals used in single-frequency laser interferometer for differentiating direction and electronic subdivision. However there usually exist three errors with the interferential signals: zero offsets error, unequal amplitude error and quadrature phase shift error. These three errors have a serious impact on subdivision precision. Based on Heydemann error compensation algorithm, it is proposed to achieve compensation of the three errors. Due to complicated operation of the Heydemann mode, a improved arithmetic is advanced to decrease the calculating time effectively in accordance with the special characteristic that only one item of data will be changed in each fitting algorithm operation. Then a real-time and dynamic compensatory circuit is designed. Taking microchip MSP430 as the core of hardware system, two input signals with the three errors are turned into digital quantity by the AD7862. After data processing in line with improved arithmetic, two ideal signals without errors are output by the AD7225. At the same time two original signals are turned into relevant square wave and imported to the differentiating direction circuit. The impulse exported from the distinguishing direction circuit is counted by the timer of the microchip. According to the number of the pulse and the soft subdivision the final result is showed by LED. The arithmetic and the circuit are adopted to test the capability of a laser interferometer with 8 times optical path difference and the measuring accuracy of 12-14nm is achieved.

  15. A new phase-shift microscope designed for high accuracy stitching interferometry

    International Nuclear Information System (INIS)

    Thomasset, Muriel; Idir, Mourad; Polack, François; Bray, Michael; Servant, Jean-Jacques

    2013-01-01

    Characterizing nanofocusing X-ray mirrors for the soon coming nano-imaging beamlines of synchrotron light sources motivates the development of new instruments with improved performances. The sensitivity and accuracy goal is now fixed well under the nm level and, at the same time, the spatial frequency range of the measurement should be pushed toward 50 mm −1 . SOLEIL synchrotron facility has therefore undertaken to equip with an interferential microscope suitable for stitching interferometry at this performance level. In order to keep control on the whole metrology chain it was decided to build a custom instrument in partnership with two small optics companies EOTECH and MBO. The new instrument is a Michelson micro-interferometer equipped with a custom-designed telecentric objective. It achieves the large depth of focus suitable for performing reliable calibrations and measurements. The concept has been validated with a predevelopment set-up, delivered in July 2010, which showed a static repeatability below 1 nm PV despite a non-thermally stabilized environment. The final instrument was delivered early this year and was installed inside SOLEIL's controlled environment facility, where thorough characterization tests are under way. Latest test results and first stitching measurements are presented

  16. Experimental study of very low permeability rocks using a high accuracy permeameter

    International Nuclear Information System (INIS)

    Larive, Elodie

    2002-01-01

    The measurement of fluid flow through 'tight' rocks is important to provide a better understanding of physical processes involved in several industrial and natural problems. These include deep nuclear waste repositories, management of aquifers, gas, petroleum or geothermal reservoirs, or earthquakes prevention. The major part of this work consisted of the design, construction and use of an elaborate experimental apparatus allowing laboratory permeability measurements (fluid flow) of very low permeability rocks, on samples at a centimetric scale, to constrain their hydraulic behaviour at realistic in-situ conditions. The accuracy permeameter allows the use of several measurement methods, the steady-state flow method, the transient pulse method, and the sinusoidal pore pressure oscillation method. Measurements were made with the pore pressure oscillation method, using different waveform periods, at several pore and confining pressure conditions, on different materials. The permeability of one natural standard, Westerly granite, and an artificial one, a micro-porous cement, were measured, and results obtained agreed with previous measurements made on these materials showing the reliability of the permeameter. A study of a Yorkshire sandstone shows a relationship between rock microstructure, permeability anisotropy and thermal cracking. Microstructure, porosity and permeability concepts, and laboratory permeability measurements specifications are presented, the permeameter is described, and then permeability results obtained on the investigated materials are reported [fr

  17. Demonstrating High-Accuracy Orbital Access Using Open-Source Tools

    Science.gov (United States)

    Gilbertson, Christian; Welch, Bryan

    2017-01-01

    Orbit propagation is fundamental to almost every space-based analysis. Currently, many system analysts use commercial software to predict the future positions of orbiting satellites. This is one of many capabilities that can replicated, with great accuracy, without using expensive, proprietary software. NASAs SCaN (Space Communication and Navigation) Center for Engineering, Networks, Integration, and Communications (SCENIC) project plans to provide its analysis capabilities using a combination of internal and open-source software, allowing for a much greater measure of customization and flexibility, while reducing recurring software license costs. MATLAB and the open-source Orbit Determination Toolbox created by Goddard Space Flight Center (GSFC) were utilized to develop tools with the capability to propagate orbits, perform line-of-sight (LOS) availability analyses, and visualize the results. The developed programs are modular and can be applied for mission planning and viability analysis in a variety of Solar System applications. The tools can perform 2 and N-body orbit propagation, find inter-satellite and satellite to ground station LOS access (accounting for intermediate oblate spheroid body blocking, geometric restrictions of the antenna field-of-view (FOV), and relativistic corrections), and create animations of planetary movement, satellite orbits, and LOS accesses. The code is the basis for SCENICs broad analysis capabilities including dynamic link analysis, dilution-of-precision navigation analysis, and orbital availability calculations.

  18. A study for high accuracy measurement of residual stress by deep hole drilling technique

    Science.gov (United States)

    Kitano, Houichi; Okano, Shigetaka; Mochizuki, Masahito

    2012-08-01

    The deep hole drilling technique (DHD) received much attention in recent years as a method for measuring through-thickness residual stresses. However, some accuracy problems occur when residual stress evaluation is performed by the DHD technique. One of the reasons is that the traditional DHD evaluation formula applies to the plane stress condition. The second is that the effects of the plastic deformation produced in the drilling process and the deformation produced in the trepanning process are ignored. In this study, a modified evaluation formula, which is applied to the plane strain condition, is proposed. In addition, a new procedure is proposed which can consider the effects of the deformation produced in the DHD process by investigating the effects in detail by finite element (FE) analysis. Then, the evaluation results obtained by the new procedure are compared with that obtained by traditional DHD procedure by FE analysis. As a result, the new procedure evaluates the residual stress fields better than the traditional DHD procedure when the measuring object is thick enough that the stress condition can be assumed as the plane strain condition as in the model used in this study.

  19. On a novel low cost high accuracy experimental setup for tomographic particle image velocimetry

    International Nuclear Information System (INIS)

    Discetti, Stefano; Ianiro, Andrea; Astarita, Tommaso; Cardone, Gennaro

    2013-01-01

    This work deals with the critical aspects related to cost reduction of a Tomo PIV setup and to the bias errors introduced in the velocity measurements by the coherent motion of the ghost particles. The proposed solution consists of using two independent imaging systems composed of three (or more) low speed single frame cameras, which can be up to ten times cheaper than double shutter cameras with the same image quality. Each imaging system is used to reconstruct a particle distribution in the same measurement region, relative to the first and the second exposure, respectively. The reconstructed volumes are then interrogated by cross-correlation in order to obtain the measured velocity field, as in the standard tomographic PIV implementation. Moreover, differently from tomographic PIV, the ghost particle distributions of the two exposures are uncorrelated, since their spatial distribution is camera orientation dependent. For this reason, the proposed solution promises more accurate results, without the bias effect of the coherent ghost particles motion. Guidelines for the implementation and the application of the present method are proposed. The performances are assessed with a parametric study on synthetic experiments. The proposed low cost system produces a much lower modulation with respect to an equivalent three-camera system. Furthermore, the potential accuracy improvement using the Motion Tracking Enhanced MART (Novara et al 2010 Meas. Sci. Technol. 21 035401) is much higher than in the case of the standard implementation of tomographic PIV. (paper)

  20. ISPA - a high accuracy X-ray and gamma camera Exhibition LEPFest 2000

    CERN Multimedia

    2000-01-01

    ISPA offers ... Ten times better resolution than Anger cameras High efficiency single gamma counting Noise reduction by sensitivity to gamma energy ...for Single Photon Emission Computed Tomography (SPECT)

  1. Interferometric capability for the Magellan Project

    Science.gov (United States)

    Carleton, Nathaniel P.; Traub, Wesley A.; Angel, J. Roger P.

    1998-07-01

    The Magellan Project is building two 6.5-m telescopes, 60 m apart, at the Las Campanas Observatory in Chile. There are on-going plans to combine the beams of the two main telescopes, and of smaller auxiliary telescopes, for interferometric measurements. In this paper we consider the array of auxiliary telescopes as a stand-alone instrument, recognizing that it will operate as such for some large fraction of the time. Our interest is sharpened by the availability of six 1.8-m optical systems, retired from the Smithsonian-Arizona Multiple-Mirror Telescope in preparation for the installation of a single-mirror 6.5-m system. We have completed a design for a 1.8-m telescope, in which the MMT components are supported on a proven tripod mount. The optics-support uses steel for stiffness, and low-thermal- expansion rods for passive stability. This array will be a powerful tool for the investigation of stellar limb darkening, surface features, and changes of diameter in pulsations, as well as dust disks, shells, and binary companions. The 1.8-m telescopes on good sites such as Magellan's should be able to operate at full aperture for interferometry at 2.2 micrometers . They should therefore be able to reach to magnitude K equals 10 or so, and thus to cover substantial samples of both main-sequence and pre-main- sequence stars, and of fully evolved stars as well.

  2. The 2016 interferometric imaging beauty contest

    Science.gov (United States)

    Sanchez-Bermudez, J.; Thiébaut, E.; Hofmann, K.-H.; Heininger, M.; Schertl, D.; Weigelt, G.; Millour, F.; Schutz, A.; Ferrari, A.; Vannier, M.; Mary, D.; Young, J.

    2016-08-01

    Image reconstruction in optical interferometry has gained considerable importance for astrophysical studies during the last decade. This has been mainly due to improvements in the imaging capabilities of existing interferometers and the expectation of new facilities in the coming years. However, despite the advances made so far, image synthesis in optical interferometry is still an open field of research. Since 2004, the community has organized a biennial contest to formally test the different methods and algorithms for image reconstruction. In 2016, we celebrated the 7th edition of the "Interferometric Imaging Beauty Contest". This initiative represented an open call to participate in the reconstruction of a selected set of simulated targets with a wavelength-dependent morphology as they could be observed by the 2nd generation of VLTI instruments. This contest represents a unique opportunity to benchmark, in a systematic way, the current advances and limitations in the field, as well as to discuss possible future approaches. In this contribution, we summarize: (a) the rules of the 2016 contest; (b) the different data sets used and the selection procedure; (c) the methods and results obtained by each one of the participants; and (d) the metric used to select the best reconstructed images. Finally, we named Karl-Heinz Hofmann and the group of the Max-Planck-Institut fur Radioastronomie as winners of this edition of the contest.

  3. Interferometric optical fiber microcantilever beam biosensor

    Science.gov (United States)

    Wavering, Thomas A.; Meller, Scott A.; Evans, Mishell K.; Pennington, Charles; Jones, Mark E.; VanTassell, Roger; Murphy, Kent A.; Velander, William H.; Valdes, E.

    2000-12-01

    With the proliferation of biological weapons, the outbreak of food poisoning occurrences, and the spread of antibiotic resistant strains of pathogenic bacteria, the demand has arisen for portable systems capable of rapid, specific, and quantitative target detection. The ability to detect minute quantities of targets will provide the means to quickly assess a health hazardous situation so that the appropriate response can be orchestrated. Conventional test results generally require hours or even several days to be reported, and there is no change for real-time feedback. An interferometric optical fiber microcantilever beam biosensor has successfully demonstrated real time detection of target molecules. The microcantilever biosensor effectively combines advanced technology from silicon micromachining, optical fiber sensor, and biochemistry to create a novel detection device. This approach utilizes affinity coatings on micromachiend cantilever beams to attract target molecules. The presence of the target molecule causes bending in the cantilever beam, which is monitored using an optical displacement system. Dose-response trials have shown measured responses at nanogram/ml concentrations of target molecules. Sensitivity is expected to extend from the nanogram to the picogram range of total captured mass as the microcantilever sensors are optimized.

  4. Interferometric microstructured polymer optical fiber ultrasound sensor for optoacoustic endoscopic imaging in biomedical applications

    DEFF Research Database (Denmark)

    Gallego, Daniel; Sáez-Rodríguez, David; Webb, David

    2014-01-01

    to conventional piezoelectric transducers. These kind of sensors, made of biocompatible polymers, are good candidates for the sensing element in an optoacoustic endoscope because of its high sensitivity, its shape and its non-brittle and non-electric nature. The acoustic sensitivity of the intrinsic fiber optic......We report a characterization of the acoustic sensitivity of microstructured polymer optical fiber interferometric sensors at ultrasonic frequencies from 100kHz to 10MHz. The use of wide-band ultrasonic fiber optic sensors in biomedical ultrasonic and optoacoustic applications is an open alternative...... interferometric sensors depends strongly of the material which is composed of. In this work we compare experimentally the intrinsic ultrasonic sensitivities of a PMMA mPOF with other three optical fibers: a singlemode silica optical fiber, a single-mode polymer optical fiber and a multimode graded...

  5. Effect of energy deposited by cosmic-ray particles on interferometric gravitational wave detectors

    International Nuclear Information System (INIS)

    Yamamoto, Kazuhiro; Hayakawa, Hideaki; Okada, Atsushi; Uchiyama, Takashi; Miyoki, Shinji; Ohashi, Masatake; Kuroda, Kazuaki; Kanda, Nobuyuki; Tatsumi, Daisuke; Tsunesada, Yoshiki

    2008-01-01

    We investigated the noise of interferometric gravitational wave detectors due to heat energy deposited by cosmic-ray particles. We derived a general formula that describes the response of a mirror against a cosmic-ray passage. We found that there are differences in the comic-ray responses (the dependence of temperature and cosmic-ray track position) in cases of interferometric and resonant gravitational wave detectors. The power spectral density of vibrations caused by low-energy secondary muons is 100 times smaller than the goal sensitivity of future second-generation interferometer projects, such as LCGT and Advanced LIGO. The arrival frequency of high-energy cosmic-ray muons that generate enough large showers inside mirrors of LCGT and Advanced LIGO is one per a millennium. We also discuss the probability of exotic-particle detection with interferometers.

  6. Gated viewing and high-accuracy three-dimensional laser radar

    DEFF Research Database (Denmark)

    Busck, Jens; Heiselberg, Henning

    2004-01-01

    , a high PRF of 32 kHz, and a high-speed camera with gate times down to 200 ps and delay steps down to 100 ps. The electronics and the software also allow for gated viewing with automatic gain control versus range, whereby foreground backscatter can be suppressed. We describe our technique for the rapid...

  7. High-accuracy measurement of ship velocities by DGPS; DGPS ni yoru sensoku keisoku no koseidoka ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, S; Koterayama, W [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

    1996-04-10

    The differential global positioning system (DGPS) can eliminate most of errors in ship velocity measurement by GPS positioning alone. Through two rounds of marine observations by towing an observation robot in summer 1995, the authors attempted high-accuracy measurement of ship velocities by DGPS, and also carried out both positioning by GPS alone and measurement using the bottom track of ADCP (acoustic Doppler current profiler). In this paper, the results obtained by these measurement methods were examined through comparison among them, and the accuracy of the measured ship velocities was considered. In DGPS measurement, both translocation method and interference positioning method were used. ADCP mounted on the observation robot allowed measurement of the velocity of current meter itself by its bottom track in shallow sea areas less than 350m. As the result of these marine observations, it was confirmed that the accuracy equivalent to that of direct measurement by bottom track is possible to be obtained by DGPS. 3 refs., 5 figs., 1 tab.

  8. High construal level can help negotiators to reach integrative agreements: The role of information exchange and judgement accuracy.

    Science.gov (United States)

    Wening, Stefanie; Keith, Nina; Abele, Andrea E

    2016-06-01

    In negotiations, a focus on interests (why negotiators want something) is key to integrative agreements. Yet, many negotiators spontaneously focus on positions (what they want), with suboptimal outcomes. Our research applies construal-level theory to negotiations and proposes that a high construal level instigates a focus on interests during negotiations which, in turn, positively affects outcomes. In particular, we tested the notion that the effect of construal level on outcomes was mediated by information exchange and judgement accuracy. Finally, we expected the mere mode of presentation of task material to affect construal levels and manipulated construal levels using concrete versus abstract negotiation tasks. In two experiments, participants negotiated in dyads in either a high- or low-construal-level condition. In Study 1, high-construal-level dyads outperformed dyads in the low-construal-level condition; this main effect was mediated by information exchange. Study 2 replicated both the main and mediation effects using judgement accuracy as mediator and additionally yielded a positive effect of a high construal level on a second, more complex negotiation task. These results not only provide empirical evidence for the theoretically proposed link between construal levels and negotiation outcomes but also shed light on the processes underlying this effect. © 2015 The British Psychological Society.

  9. Neutrino mass from cosmology: impact of high-accuracy measurement of the Hubble constant

    Energy Technology Data Exchange (ETDEWEB)

    Sekiguchi, Toyokazu [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582 (Japan); Ichikawa, Kazuhide [Department of Micro Engineering, Kyoto University, Kyoto 606-8501 (Japan); Takahashi, Tomo [Department of Physics, Saga University, Saga 840-8502 (Japan); Greenhill, Lincoln, E-mail: sekiguti@icrr.u-tokyo.ac.jp, E-mail: kazuhide@me.kyoto-u.ac.jp, E-mail: tomot@cc.saga-u.ac.jp, E-mail: greenhill@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2010-03-01

    Non-zero neutrino mass would affect the evolution of the Universe in observable ways, and a strong constraint on the mass can be achieved using combinations of cosmological data sets. We focus on the power spectrum of cosmic microwave background (CMB) anisotropies, the Hubble constant H{sub 0}, and the length scale for baryon acoustic oscillations (BAO) to investigate the constraint on the neutrino mass, m{sub ν}. We analyze data from multiple existing CMB studies (WMAP5, ACBAR, CBI, BOOMERANG, and QUAD), recent measurement of H{sub 0} (SHOES), with about two times lower uncertainty (5 %) than previous estimates, and recent treatments of BAO from the Sloan Digital Sky Survey (SDSS). We obtained an upper limit of m{sub ν} < 0.2eV (95 % C.L.), for a flat ΛCDM model. This is a 40 % reduction in the limit derived from previous H{sub 0} estimates and one-third lower than can be achieved with extant CMB and BAO data. We also analyze the impact of smaller uncertainty on measurements of H{sub 0} as may be anticipated in the near term, in combination with CMB data from the Planck mission, and BAO data from the SDSS/BOSS program. We demonstrate the possibility of a 5σ detection for a fiducial neutrino mass of 0.1 eV or a 95 % upper limit of 0.04 eV for a fiducial of m{sub ν} = 0 eV. These constraints are about 50 % better than those achieved without external constraint. We further investigate the impact on modeling where the dark-energy equation of state is constant but not necessarily -1, or where a non-flat universe is allowed. In these cases, the next-generation accuracies of Planck, BOSS, and 1 % measurement of H{sub 0} would all be required to obtain the limit m{sub ν} < 0.05−0.06 eV (95 % C.L.) for the fiducial of m{sub ν} = 0 eV. The independence of systematics argues for pursuit of both BAO and H{sub 0} measurements.

  10. Dynamic measurements of flowing cells labeled by gold nanoparticles using full-field photothermal interferometric imaging

    Science.gov (United States)

    Turko, Nir A.; Roitshtain, Darina; Blum, Omry; Kemper, Björn; Shaked, Natan T.

    2017-06-01

    We present highly dynamic photothermal interferometric phase microscopy for quantitative, selective contrast imaging of live cells during flow. Gold nanoparticles can be biofunctionalized to bind to specific cells, and stimulated for local temperature increase due to plasmon resonance, causing a rapid change of the optical phase. These phase changes can be recorded by interferometric phase microscopy and analyzed to form an image of the binding sites of the nanoparticles in the cells, gaining molecular specificity. Since the nanoparticle excitation frequency might overlap with the sample dynamics frequencies, photothermal phase imaging was performed on stationary or slowly dynamic samples. Furthermore, the computational analysis of the photothermal signals is time consuming. This makes photothermal imaging unsuitable for applications requiring dynamic imaging or real-time analysis, such as analyzing and sorting cells during fast flow. To overcome these drawbacks, we utilized an external interferometric module and developed new algorithms, based on discrete Fourier transform variants, enabling fast analysis of photothermal signals in highly dynamic live cells. Due to the self-interference module, the cells are imaged with and without excitation in video-rate, effectively increasing signal-to-noise ratio. Our approach holds potential for using photothermal cell imaging and depletion in flow cytometry.

  11. Challenges in high accuracy surface replication for micro optics and micro fluidics manufacture

    DEFF Research Database (Denmark)

    Tosello, Guido; Hansen, Hans Nørgaard; Calaon, Matteo

    2014-01-01

    Patterning the surface of polymer components with microstructured geometries is employed in optical and microfluidic applications. Mass fabrication of polymer micro structured products is enabled by replication technologies such as injection moulding. Micro structured tools are also produced...... by replication technologies such as nickel electroplating. All replication steps are enabled by a high precision master and high reproduction fidelity to ensure that the functionalities associated with the design are transferred to the final component. Engineered surface micro structures can be either...

  12. A content analysis of the quantity and accuracy of dietary supplement information found in magazines with high adolescent readership.

    Science.gov (United States)

    Shaw, Patricia; Zhang, Vivien; Metallinos-Katsaras, Elizabeth

    2009-02-01

    The objective of this study was to examine the quantity and accuracy of dietary supplement (DS) information through magazines with high adolescent readership. Eight (8) magazines (3 teen and 5 adult with high teen readership) were selected. A content analysis for DS was conducted on advertisements and editorials (i.e., articles, advice columns, and bulletins). Noted claims/cautions regarding DS were evaluated for accuracy using Medlineplus.gov and Naturaldatabase.com. Claims for dietary supplements with three or more types of ingredients and those in advertisements were not evaluated. Advertisements were evaluated with respect to size, referenced research, testimonials, and Dietary Supplement Health and Education Act of 1994 (DSHEA) warning visibility. Eighty-eight (88) issues from eight magazines yielded 238 DS references. Fifty (50) issues from five magazines contained no DS reference. Among teen magazines, seven DS references were found: five in the editorials and two in advertisements. In adult magazines, 231 DS references were found: 139 in editorials and 92 in advertisements. Of the 88 claims evaluated, 15% were accurate, 23% were inconclusive, 3% were inaccurate, 5% were partially accurate, and 55% were unsubstantiated (i.e., not listed in reference databases). Of the 94 DS evaluated in advertisements, 43% were full page or more, 79% did not have a DSHEA warning visible, 46% referred to research, and 32% used testimonials. Teen magazines contain few references to DS, none accurate. Adult magazines that have a high teen readership contain a substantial amount of DS information with questionable accuracy, raising concerns that this information may increase the chances of inappropriate DS use by adolescents, thereby increasing the potential for unexpected effects or possible harm.

  13. Interethnic differences in the accuracy of anthropometric indicators of obesity in screening for high risk of coronary heart disease

    Science.gov (United States)

    Herrera, VM; Casas, JP; Miranda, JJ; Perel, P; Pichardo, R; González, A; Sanchez, JR; Ferreccio, C; Aguilera, X; Silva, E; Oróstegui, M; Gómez, LF; Chirinos, JA; Medina-Lezama, J; Pérez, CM; Suárez, E; Ortiz, AP; Rosero, L; Schapochnik, N; Ortiz, Z; Ferrante, D; Diaz, M; Bautista, LE

    2009-01-01

    Background Cut points for defining obesity have been derived from mortality data among Whites from Europe and the United States and their accuracy to screen for high risk of coronary heart disease (CHD) in other ethnic groups has been questioned. Objective To compare the accuracy and to define ethnic and gender-specific optimal cut points for body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) when they are used in screening for high risk of CHD in the Latin-American and the US populations. Methods We estimated the accuracy and optimal cut points for BMI, WC and WHR to screen for CHD risk in Latin Americans (n=18 976), non-Hispanic Whites (Whites; n=8956), non-Hispanic Blacks (Blacks; n=5205) and Hispanics (n=5803). High risk of CHD was defined as a 10-year risk ≥20% (Framingham equation). The area under the receiver operator characteristic curve (AUC) and the misclassification-cost term were used to assess accuracy and to identify optimal cut points. Results WHR had the highest AUC in all ethnic groups (from 0.75 to 0.82) and BMI had the lowest (from 0.50 to 0.59). Optimal cut point for BMI was similar across ethnic/gender groups (27 kg/m2). In women, cut points for WC (94 cm) and WHR (0.91) were consistent by ethnicity. In men, cut points for WC and WHR varied significantly with ethnicity: from 91 cm in Latin Americans to 102 cm in Whites, and from 0.94 in Latin Americans to 0.99 in Hispanics, respectively. Conclusion WHR is the most accurate anthropometric indicator to screen for high risk of CHD, whereas BMI is almost uninformative. The same BMI cut point should be used in all men and women. Unique cut points for WC and WHR should be used in all women, but ethnic-specific cut points seem warranted among men. PMID:19238159

  14. High accuracy and precision micro injection moulding of thermoplastic elastomers micro ring production

    DEFF Research Database (Denmark)

    Calaon, Matteo; Tosello, Guido; Elsborg, René

    2016-01-01

    The mass-replication nature of the process calls for fast monitoring of process parameters and product geometrical characteristics. In this direction, the present study addresses the possibility to develop a micro manufacturing platform for micro assembly injection moulding with real-time process....../product monitoring and metrology. The study represent a new concept yet to be developed with great potential for high precision mass-manufacturing of highly functional 3D multi-material (i.e. including metal/soft polymer) micro components. The activities related to HINMICO project objectives proves the importance...

  15. High Accuracy Three-dimensional Simulation of Micro Injection Moulded Parts

    DEFF Research Database (Denmark)

    Tosello, Guido; Costa, F. S.; Hansen, Hans Nørgaard

    2011-01-01

    Micro injection moulding (μIM) is the key replication technology for high precision manufacturing of polymer micro products. Data analysis and simulations on micro-moulding experiments have been conducted during the present validation study. Detailed information about the μIM process was gathered...

  16. Museum genomics: low-cost and high-accuracy genetic data from historical specimens.

    Science.gov (United States)

    Rowe, Kevin C; Singhal, Sonal; Macmanes, Matthew D; Ayroles, Julien F; Morelli, Toni Lyn; Rubidge, Emily M; Bi, Ke; Moritz, Craig C

    2011-11-01

    Natural history collections are unparalleled repositories of geographical and temporal variation in faunal conditions. Molecular studies offer an opportunity to uncover much of this variation; however, genetic studies of historical museum specimens typically rely on extracting highly degraded and chemically modified DNA samples from skins, skulls or other dried samples. Despite this limitation, obtaining short fragments of DNA sequences using traditional PCR amplification of DNA has been the primary method for genetic study of historical specimens. Few laboratories have succeeded in obtaining genome-scale sequences from historical specimens and then only with considerable effort and cost. Here, we describe a low-cost approach using high-throughput next-generation sequencing to obtain reliable genome-scale sequence data from a traditionally preserved mammal skin and skull using a simple extraction protocol. We show that single-nucleotide polymorphisms (SNPs) from the genome sequences obtained independently from the skin and from the skull are highly repeatable compared to a reference genome. © 2011 Blackwell Publishing Ltd.

  17. Algorithm of dynamic regulation of a system of duct, for a high accuracy climatic system

    Science.gov (United States)

    Arbatskiy, A. A.; Afonina, G. N.; Glazov, V. S.

    2017-11-01

    Currently, major part of climatic system, are stationary in projected mode only. At the same time, many modern industrial sites, require constant or periodical changes in technological process. That is 80% of the time, the industrial site is not require ventilation system in projected mode and high precision of climatic parameters must maintain. While that not constantly is in use for climatic systems, which use in parallel for different rooms, we will be have a problem for balance of duct system. For this problem, was created the algorithm for quantity regulation, with minimal changes. Dynamic duct system: Developed of parallel control system of air balance, with high precision of climatic parameters. The Algorithm provide a permanent pressure in main duct, in different a flow of air. Therefore, the ending devises air flow have only one parameter for regulation - flaps open area. Precision of regulation increase and the climatic system provide high precision for temperature and humidity (0,5C for temperature, 5% for relative humidity). Result: The research has been made in CFD-system - PHOENICS. Results for velocity of air in duct, for pressure of air in duct for different operation mode, has been obtained. Equation for air valves positions, with different parameters for climate in room’s, has been obtained. Energy saving potential for dynamic duct system, for different types of a rooms, has been calculated.

  18. High-accuracy alignment based on atmospherical dispersion - technological approaches and solutions for the dual-wavelength transmitter

    International Nuclear Information System (INIS)

    Burkhard, Boeckem

    1999-01-01

    In the course of the progressive developments of sophisticated geodetic systems utilizing electromagnetic waves in the visible or near IR-range a more detailed knowledge of the propagation medium and coevally solutions of atmospherically induced limitations will become important. An alignment system based on atmospherical dispersion, called a dispersometer, is a metrological solution to the atmospherically induced limitations, in optical alignment and direction observations of high accuracy. In the dispersometer we are using the dual-wavelength method for dispersive air to obtain refraction compensated angle measurements, the detrimental impact of atmospheric turbulence notwithstanding. The principle of the dual-wavelength method utilizes atmospherical dispersion, i.e. the wavelength dependence of the refractive index. The difference angle between two light beams of different wavelengths, which is called the dispersion angle Δβ, is to first approximation proportional to the refraction angle: β IR ν(β blue - β IR ) = ν Δβ, this equation implies that the dispersion angle has to be measured at least 42 times more accurate than the desired accuracy of the refraction angle for the wavelengths used in the present dispersometer. This required accuracy constitutes one major difficulty for the instrumental performance in applying the dispersion effect. However, the dual-wavelength method can only be successfully used in an optimized transmitter-receiver combination. Beyond the above mentioned resolution requirement for the detector, major difficulties in instrumental realization arise in the availability of a suitable dual-wavelength laser light source, laser light modulation with a very high extinction ratio and coaxial emittance of mono-mode radiation at both wavelengths. Therefore, this paper focuses on the solutions of the dual-wavelength transmitter introducing a new hardware approach and a complete re-design of the in [1] proposed conception of the dual

  19. Interferometric interrogation of π-phase shifted fiber Bragg grating sensors

    Science.gov (United States)

    Srivastava, Deepa; Tiwari, Umesh; Das, Bhargab

    2018-03-01

    Interferometric interrogation technique realized for conventional fiber Bragg grating (FBG) sensors is historically known to offer the highest sensitivity measurements, however, it has not been yet explored for π-phase-shifted FBG (πFBG) sensors. This, we believe, is due to the complex nature of the reflection/transmission spectrum of a πFBG, which cannot be directly used for interferometric interrogation purpose. Therefore, we propose here an innovative as well as simple concept towards this direction, wherein, the transmission spectrum of a πFBG sensor is optically filtered using a specially designed fiber grating. The resulting filtered spectrum retains the entire characteristics of a πFBG sensor and hence the filtered spectrum can be interrogated with interferometric principles. Furthermore, due to the extremely narrow transmission notch of a πFBG sensor, a fiber interferometer can be realized with significantly longer path difference. This leads to substantially enhanced detection limit as compared to sensors based on a regular FBG of similar length. Theoretical analysis demonstrates that high resolution weak dynamic strain measurement down to 4 pε /√{ Hz } is easily achievable. Preliminary experimental results are also presented as proof-of-concept of the proposed interrogation principle.

  20. Event reconstruction using the radio-interferometric technique in the frame of AERA

    Energy Technology Data Exchange (ETDEWEB)

    Rogozin, Dmytro [Institut fuer Experimentelle Kernphysik, Karlsruher Institut fuer Technologie (KIT) (Germany); Collaboration: Pierre-Auger-Collaboration

    2016-07-01

    It is a well-known fact that there is coherent radio emission induced by extensive air-showers. This fact is exploited in the Auger Engineering Radio Array (AERA), the radio extension of the Pierre Auger Observatory. This is a unique radio experiment due to its world-largest size of 17 km{sup 2}, and due to its precise nanosecond timing calibration. These features become crucial for detection of highly inclined air-showers with their very large foot-prints, and for the ability to apply interferometric reconstruction techniques. The standard reconstruction techniques typically treat all radio stations as separate detectors. Nevertheless there is a possibility to do an interferometric analysis. This means combining all detected signals from all antennas in a specific way. In this talk we present a beam-forming interferometric technique and its application to AERA. According to the definition of the beam-forming quantities one can expect its correlation with the shower parameters such as energy of the primary particle and distance to the shower maximum. At the first step, Monte-Carlo simulations of AERA events including the noise from measured events were used to test these dependencies. The results and the future perspectives of this method are discussed with a particular emphasis on very inclined air-showers where the aforementioned correlations are assumed to be strongest.

  1. Modelling and Control of Stepper Motors for High Accuracy Positioning Systems Used in Radioactive Environments

    CERN Document Server

    Picatoste Ruilope, Ricardo; Masi, Alessandro

    Hybrid Stepper Motors are widely used in open-loop position applications. They are the choice of actuation for the collimators in the Large Hadron Collider, the largest particle accelerator at CERN. In this case the positioning requirements and the highly radioactive operating environment are unique. The latter forces both the use of long cables to connect the motors to the drives which act as transmission lines and also prevents the use of standard position sensors. However, reliable and precise operation of the collimators is critical for the machine, requiring the prevention of step loss in the motors and maintenance to be foreseen in case of mechanical degradation. In order to make the above possible, an approach is proposed for the application of an Extended Kalman Filter to a sensorless stepper motor drive, when the motor is separated from its drive by long cables. When the long cables and high frequency pulse width modulated control voltage signals are used together, the electrical signals difer greatl...

  2. The study of optimization on process parameters of high-accuracy computerized numerical control polishing

    Science.gov (United States)

    Huang, Wei-Ren; Huang, Shih-Pu; Tsai, Tsung-Yueh; Lin, Yi-Jyun; Yu, Zong-Ru; Kuo, Ching-Hsiang; Hsu, Wei-Yao; Young, Hong-Tsu

    2017-09-01

    Spherical lenses lead to forming spherical aberration and reduced optical performance. Consequently, in practice optical system shall apply a combination of spherical lenses for aberration correction. Thus, the volume of the optical system increased. In modern optical systems, aspherical lenses have been widely used because of their high optical performance with less optical components. However, aspherical surfaces cannot be fabricated by traditional full aperture polishing process due to their varying curvature. Sub-aperture computer numerical control (CNC) polishing is adopted for aspherical surface fabrication in recent years. By using CNC polishing process, mid-spatial frequency (MSF) error is normally accompanied during this process. And the MSF surface texture of optics decreases the optical performance for high precision optical system, especially for short-wavelength applications. Based on a bonnet polishing CNC machine, this study focuses on the relationship between MSF surface texture and CNC polishing parameters, which include feed rate, head speed, track spacing and path direction. The power spectral density (PSD) analysis is used to judge the MSF level caused by those polishing parameters. The test results show that controlling the removal depth of single polishing path, through the feed rate, and without same direction polishing path for higher total removal depth can efficiently reduce the MSF error. To verify the optical polishing parameters, we divided a correction polishing process to several polishing runs with different direction polishing paths. Compare to one shot polishing run, multi-direction path polishing plan could produce better surface quality on the optics.

  3. High accuracy injection circuit for the calibration of a large pixel sensor matrix

    International Nuclear Information System (INIS)

    Quartieri, E.; Comotti, D.; Manghisoni, M.

    2013-01-01

    Semiconductor pixel detectors, for particle tracking and vertexing in high energy physics experiments as well as for X-ray imaging, in particular for synchrotron light sources and XFELs, require a large area sensor matrix. This work will discuss the design and the characterization of a high-linearity, low dispersion injection circuit to be used for pixel-level calibration of detector readout electronics in a large pixel sensor matrix. The circuit provides a useful tool for the characterization of the readout electronics of the pixel cell unit for both monolithic active pixel sensors and hybrid pixel detectors. In the latter case, the circuit allows for precise analogue test of the readout channel already at the chip level, when no sensor is connected. Moreover, it provides a simple means for calibration of readout electronics once the detector has been connected to the chip. Two injection techniques can be provided by the circuit: one for a charge sensitive amplification and the other for a transresistance readout channel. The aim of the paper is to describe the architecture and the design guidelines of the calibration circuit, which has been implemented in a 130 nm CMOS technology. Moreover, experimental results of the proposed injection circuit will be presented in terms of linearity and dispersion

  4. Accuracy of an automated system for tuberculosis detection on chest radiographs in high-risk screening.

    Science.gov (United States)

    Melendez, J; Hogeweg, L; Sánchez, C I; Philipsen, R H H M; Aldridge, R W; Hayward, A C; Abubakar, I; van Ginneken, B; Story, A

    2018-05-01

    Tuberculosis (TB) screening programmes can be optimised by reducing the number of chest radiographs (CXRs) requiring interpretation by human experts. To evaluate the performance of computerised detection software in triaging CXRs in a high-throughput digital mobile TB screening programme. A retrospective evaluation of the software was performed on a database of 38 961 postero-anterior CXRs from unique individuals seen between 2005 and 2010, 87 of whom were diagnosed with TB. The software generated a TB likelihood score for each CXR. This score was compared with a reference standard for notified active pulmonary TB using receiver operating characteristic (ROC) curve and localisation ROC (LROC) curve analyses. On ROC curve analysis, software specificity was 55.71% (95%CI 55.21-56.20) and negative predictive value was 99.98% (95%CI 99.95-99.99), at a sensitivity of 95%. The area under the ROC curve was 0.90 (95%CI 0.86-0.93). Results of the LROC curve analysis were similar. The software could identify more than half of the normal images in a TB screening setting while maintaining high sensitivity, and may therefore be used for triage.

  5. A three axis turntable's online initial state measurement method based on the high-accuracy laser gyro SINS

    Science.gov (United States)

    Gao, Chunfeng; Wei, Guo; Wang, Qi; Xiong, Zhenyu; Wang, Qun; Long, Xingwu

    2016-10-01

    As an indispensable equipment in inertial technology tests, the three-axis turntable is widely used in the calibration of various types inertial navigation systems (INS). In order to ensure the calibration accuracy of INS, we need to accurately measure the initial state of the turntable. However, the traditional measuring method needs a lot of exterior equipment (such as level instrument, north seeker, autocollimator, etc.), and the test processing is complex, low efficiency. Therefore, it is relatively difficult for the inertial measurement equipment manufacturers to realize the self-inspection of the turntable. Owing to the high precision attitude information provided by the laser gyro strapdown inertial navigation system (SINS) after fine alignment, we can use it as the attitude reference of initial state measurement of three-axis turntable. For the principle that the fixed rotation vector increment is not affected by measuring point, we use the laser gyro INS and the encoder of the turntable to provide the attitudes of turntable mounting plat. Through this way, the high accuracy measurement of perpendicularity error and initial attitude of the three-axis turntable has been achieved.

  6. High-accuracy measurement and compensation of grating line-density error in a tiled-grating compressor

    Science.gov (United States)

    Zhao, Dan; Wang, Xiao; Mu, Jie; Li, Zhilin; Zuo, Yanlei; Zhou, Song; Zhou, Kainan; Zeng, Xiaoming; Su, Jingqin; Zhu, Qihua

    2017-02-01

    The grating tiling technology is one of the most effective means to increase the aperture of the gratings. The line-density error (LDE) between sub-gratings will degrade the performance of the tiling gratings, high accuracy measurement and compensation of the LDE are of significance to improve the output pulses characteristics of the tiled-grating compressor. In this paper, the influence of LDE on the output pulses of the tiled-grating compressor is quantitatively analyzed by means of numerical simulation, the output beams drift and output pulses broadening resulting from the LDE are presented. Based on the numerical results we propose a compensation method to reduce the degradations of the tiled grating compressor by applying angular tilt error and longitudinal piston error at the same time. Moreover, a monitoring system is setup to measure the LDE between sub-gratings accurately and the dispersion variation due to the LDE is also demonstrated based on spatial-spectral interference. In this way, we can realize high-accuracy measurement and compensation of the LDE, and this would provide an efficient way to guide the adjustment of the tiling gratings.

  7. High accuracy velocity control method for the french moving-coil watt balance

    International Nuclear Information System (INIS)

    Topcu, Suat; Chassagne, Luc; Haddad, Darine; Alayli, Yasser; Juncar, Patrick

    2004-01-01

    We describe a novel method of velocity control dedicated to the French moving-coil watt balance. In this project, a coil has to move in a magnetic field at a velocity of 2 mm s -1 with a relative uncertainty of 10 -9 over 60 mm. Our method is based on the use of both a heterodyne Michelson's interferometer, a two-level translation stage, and a homemade high frequency phase-shifting electronic circuit. To quantify the stability of the velocity, the output of the interferometer is sent into a frequency counter and the Doppler frequency shift is recorded. The Allan standard deviation has been used to calculate the stability and a σ y (τ) of about 2.2x10 -9 over 400 s has been obtained

  8. Real-time and high accuracy frequency measurements for intermediate frequency narrowband signals

    Science.gov (United States)

    Tian, Jing; Meng, Xiaofeng; Nie, Jing; Lin, Liwei

    2018-01-01

    Real-time and accurate measurements of intermediate frequency signals based on microprocessors are difficult due to the computational complexity and limited time constraints. In this paper, a fast and precise methodology based on the sigma-delta modulator is designed and implemented by first generating the twiddle factors using the designed recursive scheme. This scheme requires zero times of multiplications and only half amounts of addition operations by using the discrete Fourier transform (DFT) and the combination of the Rife algorithm and Fourier coefficient interpolation as compared with conventional methods such as DFT and Fast Fourier Transform. Experimentally, when the sampling frequency is 10 MHz, the real-time frequency measurements with intermediate frequency and narrowband signals have a measurement mean squared error of ±2.4 Hz. Furthermore, a single measurement of the whole system only requires approximately 0.3 s to achieve fast iteration, high precision, and less calculation time.

  9. A high-accuracy image registration algorithm using phase-only correlation for dental radiographs

    International Nuclear Information System (INIS)

    Ito, Koichi; Nikaido, Akira; Aoki, Takafumi; Kosuge, Eiko; Kawamata, Ryota; Kashima, Isamu

    2008-01-01

    Dental radiographs have been used for the accurate assessment and treatment of dental diseases. The nonlinear deformation between two dental radiographs may be observed, even if they are taken from the same oral regions of the subject. For an accurate diagnosis, the complete geometric registration between radiographs is required. This paper presents an efficient dental radiograph registration algorithm using Phase-Only Correlation (POC) function. The use of phase components in 2D (two-dimensional) discrete Fourier transforms of dental radiograph images makes possible to achieve highly robust image registration and recognition. Experimental evaluation using a dental radiograph database indicates that the proposed algorithm exhibits efficient recognition performance even for distorted radiographs. (author)

  10. Combination volumetric and gravimetric sorption instrument for high accuracy measurements of methane adsorption

    Science.gov (United States)

    Burress, Jacob; Bethea, Donald; Troub, Brandon

    2017-05-01

    The accurate measurement of adsorbed gas up to high pressures (˜100 bars) is critical for the development of new materials for adsorbed gas storage. The typical Sievert-type volumetric method introduces accumulating errors that can become large at maximum pressures. Alternatively, gravimetric methods employing microbalances require careful buoyancy corrections. In this paper, we present a combination gravimetric and volumetric system for methane sorption measurements on samples between ˜0.5 and 1 g. The gravimetric method described requires no buoyancy corrections. The tandem use of the gravimetric method allows for a check on the highest uncertainty volumetric measurements. The sources and proper calculation of uncertainties are discussed. Results from methane measurements on activated carbon MSC-30 and metal-organic framework HKUST-1 are compared across methods and within the literature.

  11. Accuracy of W' Recovery Kinetics in High Performance Cyclists - Modelling Intermittent Work Capacity.

    Science.gov (United States)

    Bartram, Jason C; Thewlis, Dominic; Martin, David T; Norton, Kevin I

    2017-10-16

    With knowledge of an individual's critical power (CP) and W' the SKIBA 2 model provides a framework with which to track W' balance during intermittent high intensity work bouts. There are fears the time constant controlling the recovery rate of W' (τ W' ) may require refinement to enable effective use in an elite population. Four elite endurance cyclists completed an array of intermittent exercise protocols to volitional exhaustion. Each protocol lasted approximately 3.5-6 minutes and featured a range of recovery intensities, set in relation to athlete's CPs (DCP). Using the framework of the SKIBA 2 model, the τ W ' values were modified for each protocol to achieve an accurate W' at volitional exhaustion. Modified τ W ' values were compared to equivalent SKIBA 2 τ W ' values to assess the difference in recovery rates for this population. Plotting modified τ W ' values against DCP showed the adjusted relationship between work-rate and recovery-rate. Comparing modified τ W' values against the SKIBA 2 τ W' values showed a negative bias of 112±46s (mean±95%CL), suggesting athlete's recovered W' faster than predicted by SKIBA 2 (p=0.0001). The modified τ W' to DCP relationship was best described by a power function: τ W' =2287.2∗D CP -0.688 (R 2 = 0.433). The current SKIBA 2 model is not appropriate for use in elite cyclists as it under predicts the recovery rate of W'. The modified τ W' equation presented will require validation, but appears more appropriate for high performance athletes. Individual τ W' relationships may be necessary in order to maximise the model's validity.

  12. Accuracy of Administrative Codes for Distinguishing Positive Pressure Ventilation from High-Flow Nasal Cannula.

    Science.gov (United States)

    Good, Ryan J; Leroue, Matthew K; Czaja, Angela S

    2018-06-07

    Noninvasive positive pressure ventilation (NIPPV) is increasingly used in critically ill pediatric patients, despite limited data on safety and efficacy. Administrative data may be a good resource for observational studies. Therefore, we sought to assess the performance of the International Classification of Diseases, Ninth Revision procedure code for NIPPV. Patients admitted to the PICU requiring NIPPV or heated high-flow nasal cannula (HHFNC) over the 11-month study period were identified from the Virtual PICU System database. The gold standard was manual review of the electronic health record to verify the use of NIPPV or HHFNC among the cohort. The presence or absence of a NIPPV procedure code was determined by using administrative data. Test characteristics with 95% confidence intervals (CIs) were generated, comparing administrative data with the gold standard. Among the cohort ( n = 562), the majority were younger than 5 years, and the most common primary diagnosis was bronchiolitis. Most (82%) required NIPPV, whereas 18% required only HHFNC. The NIPPV code had a sensitivity of 91.1% (95% CI: 88.2%-93.6%) and a specificity of 57.6% (95% CI: 47.2%-67.5%), with a positive likelihood ratio of 2.15 (95% CI: 1.70-2.71) and negative likelihood ratio of 0.15 (95% CI: 0.11-0.22). Among our critically ill pediatric cohort, NIPPV procedure codes had high sensitivity but only moderate specificity. On the basis of our study results, there is a risk of misclassification, specifically failure to identify children who require NIPPV, when using administrative data to study the use of NIPPV in this population. Copyright © 2018 by the American Academy of Pediatrics.

  13. Automatic camera to laser calibration for high accuracy mobile mapping systems using INS

    Science.gov (United States)

    Goeman, Werner; Douterloigne, Koen; Gautama, Sidharta

    2013-09-01

    A mobile mapping system (MMS) is a mobile multi-sensor platform developed by the geoinformation community to support the acquisition of huge amounts of geodata in the form of georeferenced high resolution images and dense laser clouds. Since data fusion and data integration techniques are increasingly able to combine the complementary strengths of different sensor types, the external calibration of a camera to a laser scanner is a common pre-requisite on today's mobile platforms. The methods of calibration, nevertheless, are often relatively poorly documented, are almost always time-consuming, demand expert knowledge and often require a carefully constructed calibration environment. A new methodology is studied and explored to provide a high quality external calibration for a pinhole camera to a laser scanner which is automatic, easy to perform, robust and foolproof. The method presented here, uses a portable, standard ranging pole which needs to be positioned on a known ground control point. For calibration, a well studied absolute orientation problem needs to be solved. In many cases, the camera and laser sensor are calibrated in relation to the INS system. Therefore, the transformation from camera to laser contains the cumulated error of each sensor in relation to the INS. Here, the calibration of the camera is performed in relation to the laser frame using the time synchronization between the sensors for data association. In this study, the use of the inertial relative movement will be explored to collect more useful calibration data. This results in a better intersensor calibration allowing better coloring of the clouds and a more accurate depth mask for images, especially on the edges of objects in the scene.

  14. Quantum Discord Determines the Interferometric Power of Quantum States

    Science.gov (United States)

    Girolami, Davide; Souza, Alexandre M.; Giovannetti, Vittorio; Tufarelli, Tommaso; Filgueiras, Jefferson G.; Sarthour, Roberto S.; Soares-Pinto, Diogo O.; Oliveira, Ivan S.; Adesso, Gerardo

    2014-05-01

    Quantum metrology exploits quantum mechanical laws to improve the precision in estimating technologically relevant parameters such as phase, frequency, or magnetic fields. Probe states are usually tailored to the particular dynamics whose parameters are being estimated. Here we consider a novel framework where quantum estimation is performed in an interferometric configuration, using bipartite probe states prepared when only the spectrum of the generating Hamiltonian is known. We introduce a figure of merit for the scheme, given by the worst-case precision over all suitable Hamiltonians, and prove that it amounts exactly to a computable measure of discord-type quantum correlations for the input probe. We complement our theoretical results with a metrology experiment, realized in a highly controllable room-temperature nuclear magnetic resonance setup, which provides a proof-of-concept demonstration for the usefulness of discord in sensing applications. Discordant probes are shown to guarantee a nonzero phase sensitivity for all the chosen generating Hamiltonians, while classically correlated probes are unable to accomplish the estimation in a worst-case setting. This work establishes a rigorous and direct operational interpretation for general quantum correlations, shedding light on their potential for quantum technology.

  15. Analysis of high accuracy, quantitative proteomics data in the MaxQB database.

    Science.gov (United States)

    Schaab, Christoph; Geiger, Tamar; Stoehr, Gabriele; Cox, Juergen; Mann, Matthias

    2012-03-01

    MS-based proteomics generates rapidly increasing amounts of precise and quantitative information. Analysis of individual proteomic experiments has made great strides, but the crucial ability to compare and store information across different proteome measurements still presents many challenges. For example, it has been difficult to avoid contamination of databases with low quality peptide identifications, to control for the inflation in false positive identifications when combining data sets, and to integrate quantitative data. Although, for example, the contamination with low quality identifications has been addressed by joint analysis of deposited raw data in some public repositories, we reasoned that there should be a role for a database specifically designed for high resolution and quantitative data. Here we describe a novel database termed MaxQB that stores and displays collections of large proteomics projects and allows joint analysis and comparison. We demonstrate the analysis tools of MaxQB using proteome data of 11 different human cell lines and 28 mouse tissues. The database-wide false discovery rate is controlled by adjusting the project specific cutoff scores for the combined data sets. The 11 cell line proteomes together identify proteins expressed from more than half of all human genes. For each protein of interest, expression levels estimated by label-free quantification can be visualized across the cell lines. Similarly, the expression rank order and estimated amount of each protein within each proteome are plotted. We used MaxQB to calculate the signal reproducibility of the detected peptides for the same proteins across different proteomes. Spearman rank correlation between peptide intensity and detection probability of identified proteins was greater than 0.8 for 64% of the proteome, whereas a minority of proteins have negative correlation. This information can be used to pinpoint false protein identifications, independently of peptide database

  16. Determination of the QCD Λ-parameter and the accuracy of perturbation theory at high energies

    International Nuclear Information System (INIS)

    Dalla Brida, Mattia; Fritzsch, Patrick; Korzec, Tomasz; Ramos, Alberto; Sint, Stefan; Sommer, Rainer; Humboldt-Universitaet, Berlin

    2016-04-01

    We discuss the determination of the strong coupling α_M_S(m_Z) or equivalently the QCD Λ-parameter. Its determination requires the use of perturbation theory in α_s(μ) in some scheme, s, and at some energy scale μ. The higher the scale μ the more accurate perturbation theory becomes, owing to asymptotic freedom. As one step in our computation of the Λ-parameter in three-flavor QCD, we perform lattice computations in a scheme which allows us to non-perturbatively reach very high energies, corresponding to α_s=0.1 and below. We find that (continuum) perturbation theory is very accurate there, yielding a three percent error in the Λ-parameter, while data around α_s∼0.2 is clearly insufficient to quote such a precision. It is important to realize that these findings are expected to be generic, as our scheme has advantageous properties regarding the applicability of perturbation theory.

  17. Determination of the QCD Λ-parameter and the accuracy of perturbation theory at high energies

    Energy Technology Data Exchange (ETDEWEB)

    Dalla Brida, Mattia [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Fritzsch, Patrick [Univ. Autonoma de Madrid (Spain). Inst. de Fisica Teorica UAM/CSIC; Korzec, Tomasz [Wuppertal Univ. (Germany). Dept. of Physics; Ramos, Alberto [CERN - European Organization for Nuclear Research, Geneva (Switzerland). Theory Div.; Sint, Stefan [Trinity College Dublin (Ireland). School of Mathematics; Sommer, Rainer [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Collaboration: ALPHA Collaboration

    2016-04-15

    We discuss the determination of the strong coupling α{sub MS}(m{sub Z}) or equivalently the QCD Λ-parameter. Its determination requires the use of perturbation theory in α{sub s}(μ) in some scheme, s, and at some energy scale μ. The higher the scale μ the more accurate perturbation theory becomes, owing to asymptotic freedom. As one step in our computation of the Λ-parameter in three-flavor QCD, we perform lattice computations in a scheme which allows us to non-perturbatively reach very high energies, corresponding to α{sub s}=0.1 and below. We find that (continuum) perturbation theory is very accurate there, yielding a three percent error in the Λ-parameter, while data around α{sub s}∼0.2 is clearly insufficient to quote such a precision. It is important to realize that these findings are expected to be generic, as our scheme has advantageous properties regarding the applicability of perturbation theory.

  18. High-accuracy X-ray detector calibration based on cryogenic radiometry

    Science.gov (United States)

    Krumrey, M.; Cibik, L.; Müller, P.

    2010-06-01

    Cryogenic electrical substitution radiometers (ESRs) are absolute thermal detectors, based on the equivalence of electrical power and radiant power. Their core piece is a cavity absorber, which is typically made of copper to achieve a short response time. At higher photon energies, the use of copper prevents the operation of ESRs due to increasing transmittance. A new absorber design for hard X-rays has been developed at the laboratory of the Physikalisch-Technische Bundesanstalt (PTB) at the electron storage ring BESSY II. The Monte Carlo simulation code Geant4 was applied to optimize its absorptance for photon energies of up to 60 keV. The measurement of the radiant power of monochromatized synchrotron radiation was achieved with relative standard uncertainties of less than 0.2 %, covering the entire photon energy range of three beamlines from 50 eV to 60 keV. Monochromatized synchrotron radiation of high spectral purity is used to calibrate silicon photodiodes against the ESR for photon energies up to 60 keV with relative standard uncertainties below 0.3 %. For some silicon photodiodes, the photocurrent is not linear with the incident radiant power.

  19. High-accuracy X-ray detector calibration based on cryogenic radiometry

    International Nuclear Information System (INIS)

    Krumrey, M.; Cibik, L.; Mueller, P.

    2010-01-01

    Cryogenic electrical substitution radiometers (ESRs) are absolute thermal detectors, based on the equivalence of electrical power and radiant power. Their core piece is a cavity absorber, which is typically made of copper to achieve a short response time. At higher photon energies, the use of copper prevents the operation of ESRs due to increasing transmittance. A new absorber design for hard X-rays has been developed at the laboratory of the Physikalisch-Technische Bundesanstalt (PTB) at the electron storage ring BESSY II. The Monte Carlo simulation code Geant4 was applied to optimize its absorptance for photon energies of up to 60 keV. The measurement of the radiant power of monochromatized synchrotron radiation was achieved with relative standard uncertainties of less than 0.2 %, covering the entire photon energy range of three beamlines from 50 eV to 60 keV. Monochromatized synchrotron radiation of high spectral purity is used to calibrate silicon photodiodes against the ESR for photon energies up to 60 keV with relative standard uncertainties below 0.3 %. For some silicon photodiodes, the photocurrent is not linear with the incident radiant power.

  20. High-accuracy local positioning network for the alignment of the Mu2e experiment.

    Energy Technology Data Exchange (ETDEWEB)

    Hejdukova, Jana B. [Czech Technical Univ., Prague (Czech Republic)

    2017-06-01

    This Diploma thesis describes the establishment of a high-precision local positioning network and accelerator alignment for the Mu2e physics experiment. The process of establishing new network consists of few steps: design of the network, pre-analysis, installation works, measurements of the network and making adjustments. Adjustments were performed using two approaches. First is a geodetic approach of taking into account the Earth’s curvature and the metrological approach of a pure 3D Cartesian system on the other side. The comparison of those two approaches is performed and evaluated in the results and compared with expected differences. The effect of the Earth’s curvature was found to be significant for this kind of network and should not be neglected. The measurements were obtained with Absolute Tracker AT401, leveling instrument Leica DNA03 and gyrotheodolite DMT Gyromat 2000. The coordinates of the points of the reference network were determined by the Least Square Meth od and the overall view is attached as Annexes.

  1. Diagnostic accuracy for X-ray chest in interstitial lung disease as confirmed by high resolution computed tomography (HRCT) chest

    International Nuclear Information System (INIS)

    Afzal, F.; Raza, S.; Shafique, M.

    2017-01-01

    Objective: To determine the diagnostic accuracy of x-ray chest in interstitial lung disease as confirmed by high resolution computed tomography (HRCT) chest. Study Design: A cross-sectional validational study. Place and Duration of Study: Department of Diagnostic Radiology, Combined Military Hospital Rawalpindi, from Oct 2013 to Apr 2014. Material and Method: A total of 137 patients with clinical suspicion of interstitial lung disease (ILD) aged 20-50 years of both genders were included in the study. Patients with h/o previous histopathological diagnosis, already taking treatment and pregnant females were excluded. All the patients had chest x-ray and then HRCT. The x-ray and HRCT findings were recorded as presence or absence of the ILD. Results: Mean age was 40.21 ± 4.29 years. Out of 137 patients, 79 (57.66 percent) were males and 58 (42.34 percent) were females with male to female ratio of 1.36:1. Chest x-ray detected ILD in 80 (58.39 percent) patients, out of which, 72 (true positive) had ILD and 8 (false positive) had no ILD on HRCT. Overall sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of chest x-ray in diagnosing ILD was 80.0 percent, 82.98 percent, 90.0 percent, 68.42 percent and 81.02 percent respectively. Conclusion: This study concluded that chest x-ray is simple, non-invasive, economical and readily available alternative to HRCT with an acceptable diagnostic accuracy of 81 percent in the diagnosis of ILD. (author)

  2. Social power and recognition of emotional prosody: High power is associated with lower recognition accuracy than low power.

    Science.gov (United States)

    Uskul, Ayse K; Paulmann, Silke; Weick, Mario

    2016-02-01

    Listeners have to pay close attention to a speaker's tone of voice (prosody) during daily conversations. This is particularly important when trying to infer the emotional state of the speaker. Although a growing body of research has explored how emotions are processed from speech in general, little is known about how psychosocial factors such as social power can shape the perception of vocal emotional attributes. Thus, the present studies explored how social power affects emotional prosody recognition. In a correlational study (Study 1) and an experimental study (Study 2), we show that high power is associated with lower accuracy in emotional prosody recognition than low power. These results, for the first time, suggest that individuals experiencing high or low power perceive emotional tone of voice differently. (c) 2016 APA, all rights reserved).

  3. High-accuracy detection of early Parkinson's Disease using multiple characteristics of finger movement while typing.

    Directory of Open Access Journals (Sweden)

    Warwick R Adams

    Full Text Available Parkinson's Disease (PD is a progressive neurodegenerative movement disease affecting over 6 million people worldwide. Loss of dopamine-producing neurons results in a range of both motor and non-motor symptoms, however there is currently no definitive test for PD by non-specialist clinicians, especially in the early disease stages where the symptoms may be subtle and poorly characterised. This results in a high misdiagnosis rate (up to 25% by non-specialists and people can have the disease for many years before diagnosis. There is a need for a more accurate, objective means of early detection, ideally one which can be used by individuals in their home setting. In this investigation, keystroke timing information from 103 subjects (comprising 32 with mild PD severity and the remainder non-PD controls was captured as they typed on a computer keyboard over an extended period and showed that PD affects various characteristics of hand and finger movement and that these can be detected. A novel methodology was used to classify the subjects' disease status, by utilising a combination of many keystroke features which were analysed by an ensemble of machine learning classification models. When applied to two separate participant groups, this approach was able to successfully discriminate between early-PD subjects and controls with 96% sensitivity, 97% specificity and an AUC of 0.98. The technique does not require any specialised equipment or medical supervision, and does not rely on the experience and skill of the practitioner. Regarding more general application, it currently does not incorporate a second cardinal disease symptom, so may not differentiate PD from similar movement-related disorders.

  4. Advanced Interferometric Synthetic Aperture Imaging Radar (InSAR) for Dune Mapping

    Science.gov (United States)

    Havivi, Shiran; Amir, Doron; Schvartzman, Ilan; August, Yitzhak; Mamman, Shimrit; Rotman, Stanely R.; Blumberg, Dan G.

    2016-04-01

    Aeolian morphologies are formed in the presence of sufficient wind energy and available lose particles. These processes occur naturally or are further enhanced or reduced by human intervention. The dimensions of change are dependent primarily on the wind energy and surface properties. Since the 1970s, remote sensing imagery, both optical and radar, have been used for documentation and interpretation of the geomorphologic changes of sand dunes. Remote sensing studies of aeolian morphologies is mostly useful to document major changes, yet, subtle changes, occurring in a period of days or months in scales of centimeters, are very difficult to detect in imagery. Interferometric Synthetic Aperture Radar (InSAR) is an imaging technique for measuring Earth's surface topography and deformation. InSAR images are produced by measuring the radar phase difference between two separated antennas that view the same surface area. Classical InSAR is based on high coherence between two or more images. The output (interferogram) can show subtle changes with an accuracy of several millimeters to centimeters. Very little work has been done on measuring or identifying the changes in dunes using InSAR methods. The reason is that dunes tend to be less coherent than firm, stable, surfaces. This work aims to demonstrate how interferometric decorrelation can be used for identifying dune instability. We hypothesize and demonstrate that the loss of radar coherence over time on dunes can be used as an indication of the dune's instability. When SAR images are acquired at sufficiently close intervals one can measure the time it takes to lose coherence and associate this time with geomorphic stability. To achieve our goals, the coherence change detection method was used, in order to identify dune stability or instability and the dune activity level. The Nitzanim-Ashdod coastal dunes along the Mediterranean, 40 km south of Tel-Aviv, Israel, were chosen as a case study. The dunes in this area are of

  5. Refractive Index Compensation in Over-Determined Interferometric Systems

    Directory of Open Access Journals (Sweden)

    Zdeněk Buchta

    2012-10-01

    Full Text Available We present an interferometric technique based on a differential interferometry setup for measurement under atmospheric conditions. The key limiting factor in any interferometric dimensional measurement are fluctuations of the refractive index of air representing a dominating source of uncertainty when evaluated indirectly from the physical parameters of the atmosphere. Our proposal is based on the concept of an over-determined interferometric setup where a reference length is derived from a mechanical frame made from a material with a very low thermal coefficient. The technique allows one to track the variations of the refractive index of air on-line directly in the line of the measuring beam and to compensate for the fluctuations. The optical setup consists of three interferometers sharing the same beam path where two measure differentially the displacement while the third evaluates the changes in the measuring range, acting as a tracking refractometer. The principle is demonstrated in an experimental setup.

  6. A diabetes dashboard and physician efficiency and accuracy in accessing data needed for high-quality diabetes care.

    Science.gov (United States)

    Koopman, Richelle J; Kochendorfer, Karl M; Moore, Joi L; Mehr, David R; Wakefield, Douglas S; Yadamsuren, Borchuluun; Coberly, Jared S; Kruse, Robin L; Wakefield, Bonnie J; Belden, Jeffery L

    2011-01-01

    We compared use of a new diabetes dashboard screen with use of a conventional approach of viewing multiple electronic health record (EHR) screens to find data needed for ambulatory diabetes care. We performed a usability study, including a quantitative time study and qualitative analysis of information-seeking behaviors. While being recorded with Morae Recorder software and "think-aloud" interview methods, 10 primary care physicians first searched their EHR for 10 diabetes data elements using a conventional approach for a simulated patient, and then using a new diabetes dashboard for another. We measured time, number of mouse clicks, and accuracy. Two coders analyzed think-aloud and interview data using grounded theory methodology. The mean time needed to find all data elements was 5.5 minutes using the conventional approach vs 1.3 minutes using the diabetes dashboard (P dashboard (P dashboard (P dashboard improves both the efficiency and accuracy of acquiring data needed for high-quality diabetes care. Usability analysis tools can provide important insights into the value of optimizing physician use of health information technologies.

  7. High-accuracy self-calibration method for dual-axis rotation-modulating RLG-INS

    Science.gov (United States)

    Wei, Guo; Gao, Chunfeng; Wang, Qi; Wang, Qun; Long, Xingwu

    2017-05-01

    Inertial navigation system has been the core component of both military and civil navigation systems. Dual-axis rotation modulation can completely eliminate the inertial elements constant errors of the three axes to improve the system accuracy. But the error caused by the misalignment angles and the scale factor error cannot be eliminated through dual-axis rotation modulation. And discrete calibration method cannot fulfill requirements of high-accurate calibration of the mechanically dithered ring laser gyroscope navigation system with shock absorbers. This paper has analyzed the effect of calibration error during one modulated period and presented a new systematic self-calibration method for dual-axis rotation-modulating RLG-INS. Procedure for self-calibration of dual-axis rotation-modulating RLG-INS has been designed. The results of self-calibration simulation experiment proved that: this scheme can estimate all the errors in the calibration error model, the calibration precision of the inertial sensors scale factor error is less than 1ppm and the misalignment is less than 5″. These results have validated the systematic self-calibration method and proved its importance for accuracy improvement of dual -axis rotation inertial navigation system with mechanically dithered ring laser gyroscope.

  8. Location accuracy evaluation of lightning location systems using natural lightning flashes recorded by a network of high-speed cameras

    Science.gov (United States)

    Alves, J.; Saraiva, A. C. V.; Campos, L. Z. D. S.; Pinto, O., Jr.; Antunes, L.

    2014-12-01

    This work presents a method for the evaluation of location accuracy of all Lightning Location System (LLS) in operation in southeastern Brazil, using natural cloud-to-ground (CG) lightning flashes. This can be done through a multiple high-speed cameras network (RAMMER network) installed in the Paraiba Valley region - SP - Brazil. The RAMMER network (Automated Multi-camera Network for Monitoring and Study of Lightning) is composed by four high-speed cameras operating at 2,500 frames per second. Three stationary black-and-white (B&W) cameras were situated in the cities of São José dos Campos and Caçapava. A fourth color camera was mobile (installed in a car), but operated in a fixed location during the observation period, within the city of São José dos Campos. The average distance among cameras was 13 kilometers. Each RAMMER sensor position was determined so that the network can observe the same lightning flash from different angles and all recorded videos were GPS (Global Position System) time stamped, allowing comparisons of events between cameras and the LLS. The RAMMER sensor is basically composed by a computer, a Phantom high-speed camera version 9.1 and a GPS unit. The lightning cases analyzed in the present work were observed by at least two cameras, their position was visually triangulated and the results compared with BrasilDAT network, during the summer seasons of 2011/2012 and 2012/2013. The visual triangulation method is presented in details. The calibration procedure showed an accuracy of 9 meters between the accurate GPS position of the object triangulated and the result from the visual triangulation method. Lightning return stroke positions, estimated with the visual triangulation method, were compared with LLS locations. Differences between solutions were not greater than 1.8 km.

  9. Interferometric detection of single gold nanoparticles calibrated against TEM size distributions

    DEFF Research Database (Denmark)

    Zhang, Lixue; Christensen, Sune; Bendix, Pól Martin

    2015-01-01

    Single nanoparticle analysis: An interferometric optical approach calibrates sizes of gold nanoparticles (AuNPs) from the interference intensities by calibrating their interferometric signals against the corresponding transmission electron microscopy measurements. This method is used to investigate...

  10. Assessment of high precision, high accuracy Inductively Coupled Plasma-Optical Emission Spectroscopy to obtain concentration uncertainties less than 0.2% with variable matrix concentrations

    International Nuclear Information System (INIS)

    Rabb, Savelas A.; Olesik, John W.

    2008-01-01

    The ability to obtain high precision, high accuracy measurements in samples with complex matrices using High Performance Inductively Coupled Plasma-Optical Emission Spectroscopy (HP-ICP-OES) was investigated. The Common Analyte Internal Standard (CAIS) procedure was incorporated into the High Performance Inductively Coupled Plasma-Optical Emission Spectroscopy method to correct for matrix-induced changes in emission intensity ratios. Matrix matching and standard addition approaches to minimize matrix-induced errors when using High Performance Inductively Coupled Plasma-Optical Emission Spectroscopy were also assessed. The High Performance Inductively Coupled Plasma-Optical Emission Spectroscopy method was tested with synthetic solutions in a variety of matrices, alloy standard reference materials and geological reference materials

  11. THE RRAT TRAP: INTERFEROMETRIC LOCALIZATION OF RADIO PULSES FROM J0628+0909

    International Nuclear Information System (INIS)

    Law, Casey J.; Bower, Geoffrey C.; Pokorny, Martin; Rupen, Michael P.; Sowinski, Ken

    2012-01-01

    We present the first blind interferometric detection and imaging of a millisecond radio transient with an observation of transient pulsar J0628+0909. We developed a special observing mode of the Karl G. Jansky Very Large Array to produce correlated data products (i.e., visibilities and images) on a timescale of 10 ms. Correlated data effectively produce thousands of beams on the sky that can localize sources anywhere over a wide field of view. We used this new observing mode to find and image pulses from the rotating radio transient (RRAT) J0628+0909, improving its localization by two orders of magnitude. Since the location of the RRAT was only approximately known when first observed, we searched for transients using a wide-field detection algorithm based on the bispectrum, an interferometric closure quantity. Over 16 minutes of observing, this algorithm detected one transient offset roughly 1' from its nominal location; this allowed us to image the RRAT to localize it with an accuracy of 1.''6. With a priori knowledge of the RRAT location, a traditional beam-forming search of the same data found two lower significance pulses. The refined RRAT position excludes all potential multiwavelength counterparts, limiting its optical luminosity to L i ' 31 erg s –1 and disfavoring source models with luminous neutron stars.

  12. THE RRAT TRAP: INTERFEROMETRIC LOCALIZATION OF RADIO PULSES FROM J0628+0909

    Energy Technology Data Exchange (ETDEWEB)

    Law, Casey J.; Bower, Geoffrey C. [Department of Astronomy and Radio Astronomy Lab, University of California, Berkeley, CA (United States); Pokorny, Martin; Rupen, Michael P.; Sowinski, Ken [National Radio Astronomy Observatory, Socorro, NM (United States)

    2012-12-01

    We present the first blind interferometric detection and imaging of a millisecond radio transient with an observation of transient pulsar J0628+0909. We developed a special observing mode of the Karl G. Jansky Very Large Array to produce correlated data products (i.e., visibilities and images) on a timescale of 10 ms. Correlated data effectively produce thousands of beams on the sky that can localize sources anywhere over a wide field of view. We used this new observing mode to find and image pulses from the rotating radio transient (RRAT) J0628+0909, improving its localization by two orders of magnitude. Since the location of the RRAT was only approximately known when first observed, we searched for transients using a wide-field detection algorithm based on the bispectrum, an interferometric closure quantity. Over 16 minutes of observing, this algorithm detected one transient offset roughly 1' from its nominal location; this allowed us to image the RRAT to localize it with an accuracy of 1.''6. With a priori knowledge of the RRAT location, a traditional beam-forming search of the same data found two lower significance pulses. The refined RRAT position excludes all potential multiwavelength counterparts, limiting its optical luminosity to L{sub i{sup '}}<1.1 Multiplication-Sign 10{sup 31} erg s{sup -1} and disfavoring source models with luminous neutron stars.

  13. Simplifying and expanding analytical capabilities for various classes of doping agents by means of direct urine injection high performance liquid chromatography high resolution/high accuracy mass spectrometry.

    Science.gov (United States)

    Görgens, Christian; Guddat, Sven; Thomas, Andreas; Wachsmuth, Philipp; Orlovius, Anne-Katrin; Sigmund, Gerd; Thevis, Mario; Schänzer, Wilhelm

    2016-11-30

    So far, in sports drug testing compounds of different classes are processed and measured using different screening procedures. The constantly increasing number of samples in doping analysis, as well as the large number of substances with doping related, pharmacological effects require the development of even more powerful assays than those already employed in sports drug testing, indispensably with reduced sample preparation procedures. The analysis of native urine samples after direct injection provides a promising analytical approach, which thereby possesses a broad applicability to many different compounds and their metabolites, without a time-consuming sample preparation. In this study, a novel multi-target approach based on liquid chromatography and high resolution/high accuracy mass spectrometry is presented to screen for more than 200 analytes of various classes of doping agents far below the required detection limits in sports drug testing. Here, classic groups of drugs as diuretics, stimulants, β 2 -agonists, narcotics and anabolic androgenic steroids as well as various newer target compounds like hypoxia-inducible factor (HIF) stabilizers, selective androgen receptor modulators (SARMs), selective estrogen receptor modulators (SERMs), plasma volume expanders and other doping related compounds, listed in the 2016 WADA prohibited list were implemented. As a main achievement, growth hormone releasing peptides could be implemented, which chemically belong to the group of small peptides (0.99), limit of detection (0.1-25ng/mL; 3'OH-stanozolol glucuronide: 50pg/mL; dextran/HES: 10μg/mL) and matrix effects. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. The linear interplay of intrinsic and extrinsic noises ensures a high accuracy of cell fate selection in budding yeast

    Science.gov (United States)

    Li, Yongkai; Yi, Ming; Zou, Xiufen

    2014-01-01

    To gain insights into the mechanisms of cell fate decision in a noisy environment, the effects of intrinsic and extrinsic noises on cell fate are explored at the single cell level. Specifically, we theoretically define the impulse of Cln1/2 as an indication of cell fates. The strong dependence between the impulse of Cln1/2 and cell fates is exhibited. Based on the simulation results, we illustrate that increasing intrinsic fluctuations causes the parallel shift of the separation ratio of Whi5P but that increasing extrinsic fluctuations leads to the mixture of different cell fates. Our quantitative study also suggests that the strengths of intrinsic and extrinsic noises around an approximate linear model can ensure a high accuracy of cell fate selection. Furthermore, this study demonstrates that the selection of cell fates is an entropy-decreasing process. In addition, we reveal that cell fates are significantly correlated with the range of entropy decreases. PMID:25042292

  15. A direct indication of plasma potential diagnostic with fast time response and high accuracy based on a differential emissive probe

    International Nuclear Information System (INIS)

    Yao, W.E.; Hershkowitz; Intrator, T.

    1985-01-01

    The floating potential of the emissive probe has been used to directly measure the plasma potential. The authors have recently presented another method for directly indicating the plasma potential with a differential emissive probe. In this paper they describe the effects of probe size, plasma density and plasma potential fluctuation on plasma potential measurements and give methods for reducing errors. A control system with fast time response (α 20 μs) and high accuracy (the order of the probe temperature T/sub w//e) for maintaining a differential emissive probe at plasma potential has been developed. It can be operated in pulsed discharge plasma to measure plasma potential dynamic characteristics. A solid state optical coupler is employed to improve circuit performance. This system was tested experimentally by measuring the plasma potential in an argon plasma device an on the Phaedrus tandem mirror

  16. A high-accuracy extraction of the isoscalar πN scattering length from pionic deuterium data

    International Nuclear Information System (INIS)

    Phillips, Daniel R.; Baru, Vadim; Hanhart, Christoph; Nogga, Andreas; Hoferichter, Martin; Kubis, Bastian

    2010-01-01

    We present a high-accuracy calculation of the π(bar sign)d scattering length using chiral perturbation theory up to order (M π /m p ) 7/2 . For the first time isospin-violating corrections are included consistently. The resulting value of a π -bar d has a theoretical uncertainty of a few percent. We use it, together with data on pionic deuterium and pionic hydrogen atoms, to extract the isoscalar and isovector pion-nucleon scattering lengths from a combined analysis, and obtain a + (7.9±3.2)·10 -3 M π -1 and a-bar (86.3±1.0)·10 -3 M π -1 .

  17. A direct indication of plasma potential diagnostic with fast time response and high accuracy based on a differential emissive probe

    International Nuclear Information System (INIS)

    Yao, W.E.; Hershkowitz, N.; Intrator, T.

    1985-01-01

    The floating potential of the emissive probe has been used to directly measure the plasma potential. The authors have recently presented another method for directly indicating the plasma potential with a differential emissive probe. In this paper they describe the effects of probe size, plasma density and plasma potential fluctuation on plasma potential measurements and give methods for reducing errors. A control system with fast time response (≅ 20 μs) and high accuracy (the order of the probe temperature T/sub w//e) for maintaining a differential emissive probe at plasma potential has been developed. It can be operated in pulsed discharge plasma to measure plasma potential dynamic characteristics. A solid state optical coupler is employed to improve circuit performance. This system was tested experimentally by measuring the plasma potential in an argon plasma device and on the Phaedrus tandem mirror

  18. High accuracy determination of trace elements in NIST standard reference materials by isotope dilution ICP-MS

    International Nuclear Information System (INIS)

    Paulsen, P.J.; Beary, E.S.

    1996-01-01

    At NIST (National Institute of Standards and Technology), ICP-MS ID (inductively coupled mass spectrometry isotope dilution) has been used to certify a wide range of elements in a variety of materials with high accuracy. Both the chemical preparation and instrumental procedures are simpler than with other ID mass spectrometric techniques. The ICP-MS has picogram/ml detection limits for most elements using fixed operating parameters. Chemical separations are required only to remove an interference (from molecular ions as well as isobaric atoms), or to pre-concentrate the analyte. For example, chemical separations were required for the analysis of SRM 2711, Montana II Soil, but not for boron in peach leaves, SRM 1547.(3 refs., 3 tabs., 2 figs

  19. Interferometric scattering (iSCAT) microscopy: studies of biological membrane dynamics

    Science.gov (United States)

    Reina, Francesco; Galiani, Silvia; Shrestha, Dilip; Sezgin, Erdinc; Lagerholm, B. Christoffer; Cole, Daniel; Kukura, Philipp; Eggeling, Christian

    2018-02-01

    The study of the organization and dynamics of molecules in model and cellular membranes is an important topic in contemporary biophysics. Imaging and single particle tracking in this particular field, however, proves particularly demanding, as it requires simultaneously high spatio-temporal resolution and high signal-to-noise ratios. A remedy to this challenge might be Interferometric Scattering (iSCAT) microscopy, due to its fast sampling rates, label-free imaging capabilities and, most importantly, tuneable signal level output. Here we report our recent advances in the imaging and molecular tracking on phase-separated model membrane systems and live-cell membranes using this technique.

  20. Snow cover volumes dynamic monitoring during melting season using high topographic accuracy approach for a Lebanese high plateau witness sinkhole

    Science.gov (United States)

    Abou Chakra, Charbel; Somma, Janine; Elali, Taha; Drapeau, Laurent

    2017-04-01

    Climate change and its negative impact on water resource is well described. For countries like Lebanon, undergoing major population's rise and already decreasing precipitations issues, effective water resources management is crucial. Their continuous and systematic monitoring overs long period of time is therefore an important activity to investigate drought risk scenarios for the Lebanese territory. Snow cover on Lebanese mountains is the most important water resources reserve. Consequently, systematic observation of snow cover dynamic plays a major role in order to support hydrologic research with accurate data on snow cover volumes over the melting season. For the last 20 years few studies have been conducted for Lebanese snow cover. They were focusing on estimating the snow cover surface using remote sensing and terrestrial measurement without obtaining accurate maps for the sampled locations. Indeed, estimations of both snow cover area and volumes are difficult due to snow accumulation very high variability and Lebanese mountains chains slopes topographic heterogeneity. Therefore, the snow cover relief measurement in its three-dimensional aspect and its Digital Elevation Model computation is essential to estimate snow cover volume. Despite the need to cover the all lebanese territory, we favored experimental terrestrial topographic site approaches due to high resolution satellite imagery cost, its limited accessibility and its acquisition restrictions. It is also most challenging to modelise snow cover at national scale. We therefore, selected a representative witness sinkhole located at Ouyoun el Siman to undertake systematic and continuous observations based on topographic approach using a total station. After four years of continuous observations, we acknowledged the relation between snow melt rate, date of total melting and neighboring springs discharges. Consequently, we are able to forecast, early in the season, dates of total snowmelt and springs low

  1. High-accuracy vibration sensor based on a Fabry-Perot interferometer with active phase-tracking technology.

    Science.gov (United States)

    Xia, Wei; Li, Chuncheng; Hao, Hui; Wang, Yiping; Ni, Xiaoqi; Guo, Dongmei; Wang, Ming

    2018-02-01

    A novel position-sensitive Fabry-Perot interferometer was constructed with direct phase modulation by a built-in electro-optic modulator. Pure sinusoidal phase modulation of the light was produced, and the first harmonic of the interference signal was extracted to dynamically maintain the interferometer phase to the most sensitive point of the interferogram. Therefore, the minute vibration of the object was coded on the variation of the interference signal and could be directly retrieved by the output voltage of a photodetector. The operating principle and the signal processing method for active feedback control of the interference phase have been demonstrated in detail. The developed vibration sensor was calibrated through a high-precision piezo-electric transducer and tested by a nano-positioning stage under a vibration magnitude of 60 nm and a frequency of 300 Hz. The active phase-tracking method of the system provides high immunity against environmental disturbances. Experimental results show that the proposed interferometer can effectively reconstruct tiny vibration waveforms with subnanometer resolution, paving the way for high-accuracy vibration sensing, especially for micro-electro-mechanical systems/nano-electro-mechanical systems and ultrasonic devices.

  2. Combined interferometric and polarimetric diagnostics for TEXTOR

    International Nuclear Information System (INIS)

    Soltwisch, H.

    1980-01-01

    A method for combining Faraday rotation measurements with a phase modulated HCN interferometer is described. Extended to a multichannel system this technique should allow to investigate the distributions of electron density and poloidal magnetic field in a Tokamak plasma. We discuss the principle of operation and appropriate evaluation of measured data with regard to TEXTOR parameters and give an estimate for the expected experimental accuracy. (orig./GG) 891 GG/orig.- 892 KN

  3. Size-selective detection in integrated optical interferometric biosensors

    NARCIS (Netherlands)

    Mulder, Harmen K P; Ymeti, Aurel; Subramaniam, Vinod; Kanger, Johannes S

    2012-01-01

    We present a new size-selective detection method for integrated optical interferometric biosensors that can strongly enhance their performance. We demonstrate that by launching multiple wavelengths into a Young interferometer waveguide sensor it is feasible to derive refractive index changes from

  4. Improved self-reliance shearing interferometric technique for collimation testing

    Science.gov (United States)

    Zhao, Mingshan; Li, Guohua; Wang, Zhaobing; Jing, Yaling; Li, Yi

    1995-06-01

    Self-reference single plate shearing interferometric technique used for collimation testing of light beams are briefly reviewed. Two improved configurations of this self-reference interferometry with an inclined screen and matched half-field interferograms are described in detail. Sensitivity of these configurations is analyzed and compared with that of the existing ones.

  5. Rapid interferometric imaging of printed drug laden multilayer structures

    DEFF Research Database (Denmark)

    Sandler, Niklas; Kassamakov, Ivan; Ehlers, Henrik

    2014-01-01

    The developments in printing technologies allow fabrication of micron-size nano-layered delivery systems to personal specifications. In this study we fabricated layered polymer structures for drug-delivery into a microfluidic channel and aimed to interferometrically assure their topography...

  6. Advanced Virgo: a second-generation interferometric gravitational wave detector

    NARCIS (Netherlands)

    Acernese, F.; Bulten, H.J.; Rabeling, D.S.; van den Brand, J.F.J.

    2015-01-01

    Advanced Virgo is the project to upgrade the Virgo interferometric detector of gravitational waves, with the aim of increasing the number of observable galaxies (and thus the detection rate) by three orders of magnitude. The project is now in an advanced construction phase and the assembly and

  7. Correction of Interferometric and Vegetation Biases in the SRTMGL1 Spaceborne DEM with Hydrological Conditioning towards Improved Hydrodynamics Modeling in the Amazon Basin

    Directory of Open Access Journals (Sweden)

    Sebastien Pinel

    2015-12-01

    Full Text Available In the Amazon basin, the recently released SRTM Global 1 arc-second (SRTMGL1 remains the best topographic information for hydrological and hydrodynamic modeling purposes. However, its accuracy is hindered by errors, partly due to vegetation, leading to erroneous simulations. Previous efforts to remove the vegetation signal either did not account for its spatial variability or relied on a single assumed percentage of penetration of the SRTM signal. Here, we propose a systematic approach over an Amazonian floodplain to remove the vegetation signal, addressing its heterogeneity by combining estimates of vegetation height and a land cover map. We improve this approach by interpolating the first results with drainage network, field and altimetry data to obtain a hydrological conditioned DEM. The averaged interferometric and vegetation biases over the forest zone were found to be −2.0 m and 7.4 m, respectively. Comparing the original and corrected DEM, vertical validation against Ground Control Points shows a RMSE reduction of 64%. Flood extent accuracy, controlled against Landsat and JERS-1 images, stresses improvements in low and high water periods (+24% and +18%, respectively. This study also highlights that a ground truth drainage network, as a unique input during the interpolation, achieves reasonable results in terms of flood extent and hydrological characteristics.

  8. THE IMPACT OF MODERATE AND HIGH INTENSITY TOTAL BODY FATIGUE ON PASSING ACCURACY IN EXPERT AND NOVICE BASKETBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    Mark Lyons

    2006-06-01

    Full Text Available Despite the acknowledged importance of fatigue on performance in sport, ecologically sound studies investigating fatigue and its effects on sport-specific skills are surprisingly rare. The aim of this study was to investigate the effect of moderate and high intensity total body fatigue on passing accuracy in expert and novice basketball players. Ten novice basketball players (age: 23.30 ± 1.05 yrs and ten expert basketball players (age: 22.50 ± 0.41 yrs volunteered to participate in the study. Both groups performed the modified AAHPERD Basketball Passing Test under three different testing conditions: rest, moderate intensity and high intensity total body fatigue. Fatigue intensity was established using a percentage of the maximal number of squat thrusts performed by the participant in one minute. ANOVA with repeated measures revealed a significant (F 2,36 = 5.252, p = 0.01 level of fatigue by level of skill interaction. On examination of the mean scores it is clear that following high intensity total body fatigue there is a significant detriment in the passing performance of both novice and expert basketball players when compared to their resting scores. Fundamentally however, the detrimental impact of fatigue on passing performance is not as steep in the expert players compared to the novice players. The results suggest that expert or skilled players are better able to cope with both moderate and high intensity fatigue conditions and maintain a higher level of performance when compared to novice players. The findings of this research therefore, suggest the need for trainers and conditioning coaches in basketball to include moderate, but particularly high intensity exercise into their skills sessions. This specific training may enable players at all levels of the game to better cope with the demands of the game on court and maintain a higher standard of play

  9. (abstract) Studies of Interferometric Penetration into Vegetation Canopies using Multifrequency Interferometry Data at JPL

    Science.gov (United States)

    Hensley, Scott; Rodriguez, Ernesto; Truhafft, Bob; van Zyl, Jakob; Rosen, Paul; Werner, Charles; Madsen, Sren; Chapin, Elaine

    1997-01-01

    Radar interferometric observations both from spaceborne and airborne platforms have been used to generate accurate topographic maps, measure milimeter level displacements from earthquakes and volcanoes, and for making land cover classification and land cover change maps. Interferometric observations have two basic measurements, interferometric phase, which depends upon the path difference between the two antennas and the correlation. One of the key questions concerning interferometric observations of vegetated regions is where in the canopy does the interferometric phase measure the height. Results for two methods of extracting tree heights and other vegetation parameters based upon the amount of volumetric decorrelation will be presented.

  10. High-accuracy determination of the neutron flux in the new experimental area nTOF-EAR2 at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Sabate-Gilarte, M. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Universidad de Sevilla, Departamento de Fisica Atomica, Molecular y Nuclear, Sevilla (Spain); Barbagallo, M.; Colonna, N.; Damone, L.; Belloni, F.; Mastromarco, M.; Tagliente, G.; Variale, V. [Istituto Nazionale di Fisica Nucleare, Sezione di Bari, Bari (Italy); Gunsing, F.; Berthoumieux, E.; Diakaki, M.; Papaevangelou, T.; Dupont, E. [Universite Paris-Saclay, CEA Irfu, Gif-sur-Yvette (France); Zugec, P.; Bosnar, D. [University of Zagreb, Department of Physics, Faculty of Science, Zagreb (Croatia); Vlachoudis, V.; Aberle, O.; Brugger, M.; Calviani, M.; Cardella, R.; Cerutti, F.; Chiaveri, E.; Ferrari, A.; Kadi, Y.; Losito, R.; Macina, D.; Montesano, S.; Rubbia, C. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Chen, Y.H.; Audouin, L.; Tassan-Got, L. [Centre National de la Recherche Scientifique/IN2P3 - IPN, Orsay (France); Stamatopoulos, A.; Kokkoris, M.; Tsinganis, A.; Vlastou, R. [National Technical University of Athens (NTUA), Athens (Greece); Lerendegui-Marco, J.; Cortes-Giraldo, M.A.; Guerrero, C.; Quesada, J.M. [Universidad de Sevilla, Departamento de Fisica Atomica, Molecular y Nuclear, Sevilla (Spain); Villacorta, A. [University of Salamanca, Salamanca (Spain); Cosentino, L.; Finocchiaro, P.; Piscopo, M. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Musumarra, A. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Universita di Catania, Dipartimento di Fisica, Catania (Italy); Andrzejewski, J.; Gawlik, A.; Marganiec, J.; Perkowski, J. [University of Lodz, Lodz (Poland); Becares, V.; Balibrea, J.; Cano-Ott, D.; Garcia, A.R.; Gonzalez, E.; Martinez, T.; Mendoza, E. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain); Bacak, M.; Weiss, C. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Technische Universitaet Wien, Wien (Austria); Baccomi, R.; Milazzo, P.M. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Trieste (Italy); Barros, S.; Ferreira, P.; Goncalves, I.F.; Vaz, P. [Instituto Superior Tecnico, Lisbon (Portugal); Becvar, F.; Krticka, M.; Valenta, S. [Charles University, Prague (Czech Republic); Beinrucker, C.; Goebel, K.; Heftrich, T.; Reifarth, R.; Schmidt, S.; Weigand, M.; Wolf, C. [Goethe University Frankfurt, Frankfurt (Germany); Billowes, J.; Frost, R.J.W.; Ryan, J.A.; Smith, A.G.; Warren, S.; Wright, T. [University of Manchester, Manchester (United Kingdom); Caamano, M.; Deo, K.; Duran, I.; Fernandez-Dominguez, B.; Leal-Cidoncha, E.; Paradela, C.; Robles, M.S. [University of Santiago de Compostela, Santiago de Compostela (Spain); Calvino, F.; Casanovas, A.; Riego-Perez, A. [Universitat Politecnica de Catalunya, Barcelona (Spain); Castelluccio, D.M.; Lo Meo, S. [Agenzia Nazionale per le Nuove Tecnologie (ENEA), Bologna (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, Bologna (Italy); Cortes, G.; Mengoni, A. [Agenzia Nazionale per le Nuove Tecnologie (ENEA), Bologna (Italy); Domingo-Pardo, C.; Tain, J.L. [Universidad de Valencia, Instituto de Fisica Corpuscular, Valencia (Spain); Dressler, R.; Heinitz, S.; Kivel, N.; Maugeri, E.A.; Schumann, D. [Paul Scherrer Institut (PSI), Villingen (Switzerland); Furman, V.; Sedyshev, P. [Joint Institute for Nuclear Research (JINR), Dubna (Russian Federation); Gheorghe, I.; Glodariu, T.; Mirea, M.; Oprea, A. [Horia Hulubei National Institute of Physics and Nuclear Engineering, Magurele (Romania); Goverdovski, A.; Ketlerov, V.; Khryachkov, V. [Institute of Physics and Power Engineering (IPPE), Obninsk (Russian Federation); Griesmayer, E.; Jericha, E.; Kavrigin, P.; Leeb, H. [Technische Universitaet Wien, Wien (Austria); Harada, H.; Kimura, A. [Japan Atomic Energy Agency (JAEA), Tokai-mura (Japan); Hernandez-Prieto, A. [European Organization for Nuclear Research (CERN), Geneva (CH); Universitat Politecnica de Catalunya, Barcelona (ES); Heyse, J.; Schillebeeckx, P. [European Commission, Joint Research Centre, Geel (BE); Jenkins, D.G. [University of York, York (GB); Kaeppeler, F. [Karlsruhe Institute of Technology, Karlsruhe (DE); Katabuchi, T. [Tokyo Institute of Technology, Tokyo (JP); Lederer, C.; Lonsdale, S.J.; Woods, P.J. [University of Edinburgh, School of Physics and Astronomy, Edinburgh (GB); Licata, M.; Massimi, C.; Vannini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, Bologna (IT); Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (IT); Mastinu, P. [Istituto Nazionale di Fisica Nucleare, Sezione di Legnaro, Legnaro (IT); Matteucci, F. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Trieste (IT); Universita di Trieste, Dipartimento di Astronomia, Trieste (IT); Mingrone, F. [European Organization for Nuclear Research (CERN), Geneva (CH); Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, Bologna (IT); Nolte, R. [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (DE); Palomo-Pinto, F.R. [Universidad de Sevilla, Dept. Ingenieria Electronica, Escuela Tecnica Superior de Ingenieros, Sevilla (ES); Patronis, N. [University of Ioannina, Ioannina (GR); Pavlik, A. [University of Vienna, Faculty of Physics, Vienna (AT); Porras, J.I. [University of Granada, Granada (ES); Praena, J. [Universidad de Sevilla, Departamento de Fisica Atomica, Molecular y Nuclear, Sevilla (ES); University of Granada, Granada (ES); Rajeev, K.; Rout, P.C.; Saxena, A.; Suryanarayana, S.V. [Bhabha Atomic Research Centre (BARC), Mumbai (IN); Rauscher, T. [University of Hertfordshire, Centre for Astrophysics Research, Hatfield (GB); University of Basel, Department of Physics, Basel (CH); Tarifeno-Saldivia, A. [Universitat Politecnica de Catalunya, Barcelona (ES); Universidad de Valencia, Instituto de Fisica Corpuscular, Valencia (ES); Ventura, A. [Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, Bologna (IT); Wallner, A. [Australian National University, Canberra (AU)

    2017-10-15

    A new high flux experimental area has recently become operational at the nTOF facility at CERN. This new measuring station, nTOF-EAR2, is placed at the end of a vertical beam line at a distance of approximately 20 m from the spallation target. The characterization of the neutron beam, in terms of flux, spatial profile and resolution function, is of crucial importance for the feasibility study and data analysis of all measurements to be performed in the new area. In this paper, the measurement of the neutron flux, performed with different solid-state and gaseous detection systems, and using three neutron-converting reactions considered standard in different energy regions is reported. The results of the various measurements have been combined, yielding an evaluated neutron energy distribution in a wide energy range, from 2 meV to 100 MeV, with an accuracy ranging from 2%, at low energy, to 6% in the high-energy region. In addition, an absolute normalization of the nTOF-EAR2 neutron flux has been obtained by means of an activation measurement performed with {sup 197}Au foils in the beam. (orig.)

  11. The Segmented Aperture Interferometric Nulling Testbed (SAINT) I: overview and air-side system description

    Science.gov (United States)

    Hicks, Brian A.; Lyon, Richard G.; Petrone, Peter; Ballard, Marlin; Bolcar, Matthew R.; Bolognese, Jeff; Clampin, Mark; Dogoda, Peter; Dworzanski, Daniel; Helmbrecht, Michael A.; Koca, Corina; Shiri, Ron

    2016-07-01

    This work presents an overview of the Segmented Aperture Interferometric Nulling Testbed (SAINT), a project that will pair an actively-controlled macro-scale segmented mirror with the Visible Nulling Coronagraph (VNC). SAINT will incorporate the VNC's demonstrated wavefront sensing and control system to refine and quantify end-to-end high-contrast starlight suppression performance. This pathfinder testbed will be used as a tool to study and refine approaches to mitigating instabilities and complex diffraction expected from future large segmented aperture telescopes.

  12. High Accuracy Potential Energy Surface, Dipole Moment Surface, Rovibrational Energies and Line List Calculations for ^{14}NH_3

    Science.gov (United States)

    Coles, Phillip; Yurchenko, Sergei N.; Polyansky, Oleg; Kyuberis, Aleksandra; Ovsyannikov, Roman I.; Zobov, Nikolay Fedorovich; Tennyson, Jonathan

    2017-06-01

    We present a new spectroscopic potential energy surface (PES) for ^{14}NH_3, produced by refining a high accuracy ab initio PES to experimental energy levels taken predominantly from MARVEL. The PES reproduces 1722 matched J=0-8 experimental energies with a root-mean-square error of 0.035 cm-1 under 6000 cm^{-1} and 0.059 under 7200 cm^{-1}. In conjunction with a new DMS calculated using multi reference configuration interaction (MRCI) and H=aug-cc-pVQZ, N=aug-cc-pWCVQZ basis sets, an infrared (IR) line list has been computed which is suitable for use up to 2000 K. The line list is used to assign experimental lines in the 7500 - 10,500 cm^{-1} region and previously unassigned lines in HITRAN in the 6000-7000 cm^{-1} region. Oleg L. Polyansky, Roman I. Ovsyannikov, Aleksandra A. Kyuberis, Lorenzo Lodi, Jonathan Tennyson, Andrey Yachmenev, Sergei N. Yurchenko, Nikolai F. Zobov, J. Mol. Spec., 327 (2016) 21-30 Afaf R. Al Derzia, Tibor Furtenbacher, Jonathan Tennyson, Sergei N. Yurchenko, Attila G. Császár, J. Quant. Spectrosc. Rad. Trans., 161 (2015) 117-130

  13. Emergence of realism: Enhanced visual artistry and high accuracy of visual numerosity representation after left prefrontal damage.

    Science.gov (United States)

    Takahata, Keisuke; Saito, Fumie; Muramatsu, Taro; Yamada, Makiko; Shirahase, Joichiro; Tabuchi, Hajime; Suhara, Tetsuya; Mimura, Masaru; Kato, Motoichiro

    2014-05-01

    Over the last two decades, evidence of enhancement of drawing and painting skills due to focal prefrontal damage has accumulated. It is of special interest that most artworks created by such patients were highly realistic ones, but the mechanism underlying this phenomenon remains to be understood. Our hypothesis is that enhanced tendency of realism was associated with accuracy of visual numerosity representation, which has been shown to be mediated predominantly by right parietal functions. Here, we report a case of left prefrontal stroke, where the patient showed enhancement of artistic skills of realistic painting after the onset of brain damage. We investigated cognitive, functional and esthetic characteristics of the patient׳s visual artistry and visual numerosity representation. Neuropsychological tests revealed impaired executive function after the stroke. Despite that, the patient׳s visual artistry related to realism was rather promoted across the onset of brain damage as demonstrated by blind evaluation of the paintings by professional art reviewers. On visual numerical cognition tasks, the patient showed higher performance in comparison with age-matched healthy controls. These results paralleled increased perfusion in the right parietal cortex including the precuneus and intraparietal sulcus. Our data provide new insight into mechanisms underlying change in artistic style due to focal prefrontal lesion. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. High-accuracy measurements of snow Bidirectional Reflectance Distribution Function at visible and NIR wavelengths – comparison with modelling results

    Directory of Open Access Journals (Sweden)

    M. Dumont

    2010-03-01

    Full Text Available High-accuracy measurements of snow Bidirectional Reflectance Distribution Function (BRDF were performed for four natural snow samples with a spectrogonio-radiometer in the 500–2600 nm wavelength range. These measurements are one of the first sets of direct snow BRDF values over a wide range of lighting and viewing geometry. They were compared to BRDF calculated with two optical models. Variations of the snow anisotropy factor with lighting geometry, wavelength and snow physical properties were investigated. Results show that at wavelengths with small penetration depth, scattering mainly occurs in the very top layers and the anisotropy factor is controlled by the phase function. In this condition, forward scattering peak or double scattering peak is observed. In contrast at shorter wavelengths, the penetration of the radiation is much deeper and the number of scattering events increases. The anisotropy factor is thus nearly constant and decreases at grazing observation angles. The whole dataset is available on demand from the corresponding author.

  15. Determining the Accuracy of Paleomagnetic Remanence and High-Resolution Chronostratigraphy for Sedimentary Rocks using Rock Magnetics

    Science.gov (United States)

    Kodama, K. P.

    2017-12-01

    The talk will consider two broad topics in rock magnetism and paleomagnetism: the accuracy of paleomagnetic remanence and the use of rock magnetics to measure geologic time in sedimentary sequences. The accuracy of the inclination recorded by sedimentary rocks is crucial to paleogeographic reconstructions. Laboratory compaction experiments show that inclination shallows on the order of 10˚-15˚. Corrections to the inclination can be made using the effects of compaction on the directional distribution of secular variation recorded by sediments or the anisotropy of the magnetic grains carrying the ancient remanence. A summary of all the compaction correction studies as of 2012 shows that 85% of sedimentary rocks studied have enjoyed some amount of inclination shallowing. Future work should also consider the effect of grain-scale strain on paleomagnetic remanence. High resolution chronostratigraphy can be assigned to a sedimentary sequence using rock magnetics to detect astronomically-forced climate cycles. The power of the technique is relatively quick, non-destructive measurements, the objective identification of the cycles compared to facies interpretations, and the sensitivity of rock magnetics to subtle changes in sedimentary source. An example of this technique comes from using rock magnetics to identify astronomically-forced climate cycles in three globally distributed occurrences of the Shuram carbon isotope excursion. The Shuram excursion may record the oxidation of the world ocean in the Ediacaran, just before the Cambrian explosion of metazoans. Using rock magnetic cyclostratigraphy, the excursion is shown to have the same duration (8-9 Myr) in southern California, south China and south Australia. Magnetostratigraphy of the rocks carrying the excursion in California and Australia shows a reversed to normal geomagnetic field polarity transition at the excursion's nadir, thus supporting the synchroneity of the excursion globally. Both results point to a

  16. Linear Discriminant Analysis achieves high classification accuracy for the BOLD fMRI response to naturalistic movie stimuli.

    Directory of Open Access Journals (Sweden)

    Hendrik eMandelkow

    2016-03-01

    Full Text Available Naturalistic stimuli like movies evoke complex perceptual processes, which are of great interest in the study of human cognition by functional MRI (fMRI. However, conventional fMRI analysis based on statistical parametric mapping (SPM and the general linear model (GLM is hampered by a lack of accurate parametric models of the BOLD response to complex stimuli. In this situation, statistical machine-learning methods, a.k.a. multivariate pattern analysis (MVPA, have received growing attention for their ability to generate stimulus response models in a data-driven fashion. However, machine-learning methods typically require large amounts of training data as well as computational resources. In the past this has largely limited their application to fMRI experiments involving small sets of stimulus categories and small regions of interest in the brain. By contrast, the present study compares several classification algorithms known as Nearest Neighbour (NN, Gaussian Naïve Bayes (GNB, and (regularised Linear Discriminant Analysis (LDA in terms of their classification accuracy in discriminating the global fMRI response patterns evoked by a large number of naturalistic visual stimuli presented as a movie.Results show that LDA regularised by principal component analysis (PCA achieved high classification accuracies, above 90% on average for single fMRI volumes acquired 2s apart during a 300s movie (chance level 0.7% = 2s/300s. The largest source of classification errors were autocorrelations in the BOLD signal compounded by the similarity of consecutive stimuli. All classifiers performed best when given input features from a large region of interest comprising around 25% of the voxels that responded significantly to the visual stimulus. Consistent with this, the most informative principal components represented widespread distributions of co-activated brain regions that were similar between subjects and may represent functional networks. In light of these

  17. Diagnostic accuracy of cone-beam computed tomography scans with high- and low-resolution modes for the detection of root perforations.

    Science.gov (United States)

    Shokri, Abbas; Eskandarloo, Amir; Norouzi, Marouf; Poorolajal, Jalal; Majidi, Gelareh; Aliyaly, Alireza

    2018-03-01

    This study compared the diagnostic accuracy of cone-beam computed tomography (CBCT) scans obtained with 2 CBCT systems with high- and low-resolution modes for the detection of root perforations in endodontically treated mandibular molars. The root canals of 72 mandibular molars were cleaned and shaped. Perforations measuring 0.2, 0.3, and 0.4 mm in diameter were created at the furcation area of 48 roots, simulating strip perforations, or on the external surfaces of 48 roots, simulating root perforations. Forty-eight roots remained intact (control group). The roots were filled using gutta-percha (Gapadent, Tianjin, China) and AH26 sealer (Dentsply Maillefer, Ballaigues, Switzerland). The CBCT scans were obtained using the NewTom 3G (QR srl, Verona, Italy) and Cranex 3D (Soredex, Helsinki, Finland) CBCT systems in high- and low-resolution modes, and were evaluated by 2 observers. The chi-square test was used to assess the nominal variables. In strip perforations, the accuracies of low- and high-resolution modes were 75% and 83% for NewTom 3G and 67% and 69% for Cranex 3D. In root perforations, the accuracies of low- and high-resolution modes were 79% and 83% for NewTom 3G and was 56% and 73% for Cranex 3D. The accuracy of the 2 CBCT systems was different for the detection of strip and root perforations. The Cranex 3D had non-significantly higher accuracy than the NewTom 3G. In both scanners, the high-resolution mode yielded significantly higher accuracy than the low-resolution mode. The diagnostic accuracy of CBCT scans was not affected by the perforation diameter.

  18. Xpert MTB/RIF testing in a low tuberculosis incidence, high-resource setting: limitations in accuracy and clinical impact.

    Science.gov (United States)

    Sohn, Hojoon; Aero, Abebech D; Menzies, Dick; Behr, Marcel; Schwartzman, Kevin; Alvarez, Gonzalo G; Dan, Andrei; McIntosh, Fiona; Pai, Madhukar; Denkinger, Claudia M

    2014-04-01

    Xpert MTB/RIF, the first automated molecular test for tuberculosis, is transforming the diagnostic landscape in low-income countries. However, little information is available on its performance in low-incidence, high-resource countries. We evaluated the accuracy of Xpert in a university hospital tuberculosis clinic in Montreal, Canada, for the detection of pulmonary tuberculosis on induced sputum samples, using mycobacterial cultures as the reference standard. We also assessed the potential reduction in time to diagnosis and treatment initiation. We enrolled 502 consecutive patients who presented for evaluation of possible active tuberculosis (most with abnormal chest radiographs, only 18% symptomatic). Twenty-five subjects were identified to have active tuberculosis by culture. Xpert had a sensitivity of 46% (95% confidence interval [CI], 26%-67%) and specificity of 100% (95% CI, 99%-100%) for detection of Mycobacterium tuberculosis. Sensitivity was 86% (95% CI, 42%-100%) in the 7 subjects with smear-positive results, and 28% (95% CI, 10%-56%) in the remaining subjects with smear-negative, culture-positive results; in this latter group, positive Xpert results were obtained a median 12 days before culture results. Subjects with positive cultures but negative Xpert results had minimal disease: 11 of 13 had no symptoms on presentation, and mean time to positive liquid culture results was 28 days (95% CI, 25-47 days) compared with 14 days (95% CI, 8-21 days) in Xpert/culture-positive cases. Our findings suggest limited potential impact of Xpert testing in high-resource, low-incidence ambulatory settings due to lower sensitivity in the context of less extensive disease, and limited potential to expedite diagnosis beyond what is achieved with the existing, well-performing diagnostic algorithm.

  19. A simple differential steady-state method to measure the thermal conductivity of solid bulk materials with high accuracy.

    Science.gov (United States)

    Kraemer, D; Chen, G

    2014-02-01

    Accurate measurements of thermal conductivity are of great importance for materials research and development. Steady-state methods determine thermal conductivity directly from the proportionality between heat flow and an applied temperature difference (Fourier Law). Although theoretically simple, in practice, achieving high accuracies with steady-state methods is challenging and requires rather complex experimental setups due to temperature sensor uncertainties and parasitic heat loss. We developed a simple differential steady-state method in which the sample is mounted between an electric heater and a temperature-controlled heat sink. Our method calibrates for parasitic heat losses from the electric heater during the measurement by maintaining a constant heater temperature close to the environmental temperature while varying the heat sink temperature. This enables a large signal-to-noise ratio which permits accurate measurements of samples with small thermal conductance values without an additional heater calibration measurement or sophisticated heater guards to eliminate parasitic heater losses. Additionally, the differential nature of the method largely eliminates the uncertainties of the temperature sensors, permitting measurements with small temperature differences, which is advantageous for samples with high thermal conductance values and/or with strongly temperature-dependent thermal conductivities. In order to accelerate measurements of more than one sample, the proposed method allows for measuring several samples consecutively at each temperature measurement point without adding significant error. We demonstrate the method by performing thermal conductivity measurements on commercial bulk thermoelectric Bi2Te3 samples in the temperature range of 30-150 °C with an error below 3%.

  20. Theoretical and experimental study of low-finesse extrinsic Fabry-Perot interferometric fiber optic sensors

    Science.gov (United States)

    Han, Ming

    In this dissertation, detailed and systematic theoretical and experimental study of low-finesse extrinsic Fabry-Perot interferometric (EFPI) fiber optic sensors together with their signal processing methods for white-light systems are presented. The work aims to provide a better understanding of the operational principle of EFPI fiber optic sensors, and is useful and important in the design, optimization, fabrication and application of single mode fiber(SMF) EFPI (SMF-EFPI) and multimode fiber (MMF) EFPI (MMF-EFPI) sensor systems. The cases for SMF-EFPI and MMF-EFPI sensors are separately considered. In the analysis of SMF-EFPI sensors, the light transmitted in the fiber is approximated by a Gaussian beam and the obtained spectral transfer function of the sensors includes an extra phase shift due to the light coupling in the fiber end-face. This extra phase shift has not been addressed by previous researchers and is of great importance for high accuracy and high resolution signal processing of white-light SMF-EFPI systems. Fringe visibility degradation due to gap-length increase and sensor imperfections is studied. The results indicate that the fringe visibility of a SMF-EFPI sensor is relatively insensitive to the gap-length change and sensor imperfections. Based on the spectral fringe pattern predicated by the theory of SMF-EFPI sensors, a novel curve fitting signal processing method (Type 1 curve-fitting method) is presented for white-light SMF-EFPI sensor systems. Other spectral domain signal processing methods including the wavelength-tracking, the Type 2-3 curve fitting, Fourier transform, and two-point interrogation methods are reviewed and systematically analyzed. Experiments were carried out to compare the performances of these signal processing methods. The results have shown that the Type 1 curve fitting method achieves high accuracy, high resolution, large dynamic range, and the capability of absolute measurement at the same time, while others either

  1. Contrast computation methods for interferometric measurement of sensor modulation transfer function

    Science.gov (United States)

    Battula, Tharun; Georgiev, Todor; Gille, Jennifer; Goma, Sergio

    2018-01-01

    Accurate measurement of image-sensor frequency response over a wide range of spatial frequencies is very important for analyzing pixel array characteristics, such as modulation transfer function (MTF), crosstalk, and active pixel shape. Such analysis is especially significant in computational photography for the purposes of deconvolution, multi-image superresolution, and improved light-field capture. We use a lensless interferometric setup that produces high-quality fringes for measuring MTF over a wide range of frequencies (here, 37 to 434 line pairs per mm). We discuss the theoretical framework, involving Michelson and Fourier contrast measurement of the MTF, addressing phase alignment problems using a moiré pattern. We solidify the definition of Fourier contrast mathematically and compare it to Michelson contrast. Our interferometric measurement method shows high detail in the MTF, especially at high frequencies (above Nyquist frequency). We are able to estimate active pixel size and pixel pitch from measurements. We compare both simulation and experimental MTF results to a lens-free slanted-edge implementation using commercial software.

  2. Microgravity vertical gradient measurement in the site of VIRGO interferometric antenna (Pisa plain, Italy

    Directory of Open Access Journals (Sweden)

    F. Fidecaro

    2008-06-01

    Full Text Available The site of the European Gravitational Observatory (EGO located in the countryside near Pisa (Tuscany, Italy was investigated by a microgravity vertical gradient (MVG survey. The EGO site houses the VIRGO interferometric antenna for gravitational waves detection. The microgravity survey aims to highlight the gravity anomalies of high-frequency related to more superficial geological sources in order to obtain a detailed model of the lithologic setting of the VIRGO site, that will allow an estimate of the noise induced by seismic waves and by Newtonian interference. This paper presents the results of the gradiometric survey of 2006 in the area of the interferometric antenna. MVG measurements allow us to enhance the high frequency signal strongly associated with the shallow structures. The gradient gravity map shows a main negative pattern that seems related to the trending of the high density layer of gravel that was evidenced in geotechnical drillings executed along the orthogonal arms during the construction of the VIRGO complex. Calibrating the relationship between the vertical gradient and the depth of the gravel interface we have computed a model of gravity gradient for the whole VIRGO site, defining the 3D distribution of the top surface of this layer. This latter shows a NE-SW negative pattern that may represent a palaeo-bed alluvial of the Serchio from the Bientina River system.

  3. Radio Interferometric Research of Ionosphere by Signals of Space Satellites

    Directory of Open Access Journals (Sweden)

    Dugin N.

    2013-03-01

    Full Text Available Since 2012, the Radiophysical Research Institute and the Lobachevsky State University at Nizhny Novgorod, Russia and the Ventspils International Radio Astronomy Centre at Irbene, Latvia are making radio interferometric experiments on study of ionosphere parameters in a quiet (natural state of medium and research of artificial turbulence of the ionosphere, heated by the emission from the SURA facility. Remote diagnostics of the ionosphere is implemented using a method of radio sounding by signals of navigation satellites in combination with the Very Long Baseline Interferometry (VLBI method. As a result of spectral and correlation analysis, interferometric responses of the two-element (RRI–UNN and three-element (RRI–UNN–Irbene interferometers were received by observations of 12 satellites of the navigation systems GLONASS and GPS. Here the first results are reported.

  4. Investigation of organic light emitting diodes for interferometric purposes

    Science.gov (United States)

    Pakula, Anna; Zimak, Marzena; Sałbut, Leszek

    2011-05-01

    Recently the new type of light source has been introduced to the market. Organic light emitting diode (OLED) is not only interesting because of the low applying voltage, wide light emitting areas and emission efficiency. It gives the possibility to create a light source of a various shape, various color and in the near future very likely even the one that will change shape and spectrum in time in controlled way. Those opportunities have not been in our reach until now. In the paper authors try to give an answer to the question if the new light source -OLED - is suitable for interferometric purposes. Tests cover the short and long term spectrum stability, spectrum changes due to the emission area selection. In the paper the results of two OLEDs (red and white) are shown together with the result of an attempt to use them in an interferometric setup.

  5. Data multiplexing in radio interferometric calibration

    Science.gov (United States)

    Yatawatta, Sarod; Diblen, Faruk; Spreeuw, Hanno; Koopmans, L. V. E.

    2018-03-01

    New and upcoming radio interferometers will produce unprecedented amount of data that demand extremely powerful computers for processing. This is a limiting factor due to the large computational power and energy costs involved. Such limitations restrict several key data processing steps in radio interferometry. One such step is calibration where systematic errors in the data are determined and corrected. Accurate calibration is an essential component in reaching many scientific goals in radio astronomy and the use of consensus optimization that exploits the continuity of systematic errors across frequency significantly improves calibration accuracy. In order to reach full consensus, data at all frequencies need to be calibrated simultaneously. In the SKA regime, this can become intractable if the available compute agents do not have the resources to process data from all frequency channels simultaneously. In this paper, we propose a multiplexing scheme that is based on the alternating direction method of multipliers with cyclic updates. With this scheme, it is possible to simultaneously calibrate the full data set using far fewer compute agents than the number of frequencies at which data are available. We give simulation results to show the feasibility of the proposed multiplexing scheme in simultaneously calibrating a full data set when a limited number of compute agents are available.

  6. Laser amplitude stabilization for advanced interferometric gravitational wave detectors

    International Nuclear Information System (INIS)

    Barr, B W; Strain, K A; Killow, C J

    2005-01-01

    We present results of experiments into the stabilization of the amplitude of Nd:YAG lasers for use in advanced gravitational wave detectors. By feeding back directly to the pump-diode driving current we achieved shot-noise-limited stabilization at frequencies up to several kHz with some residual noise at lower frequencies (sub ∼100 Hz). The method used is applicable to higher powered laser systems planned for advanced interferometric gravitational wave detectors

  7. High-throughput microsatellite genotyping in ecology: improved accuracy, efficiency, standardization and success with low-quantity and degraded DNA.

    Science.gov (United States)

    De Barba, M; Miquel, C; Lobréaux, S; Quenette, P Y; Swenson, J E; Taberlet, P

    2017-05-01

    Microsatellite markers have played a major role in ecological, evolutionary and conservation research during the past 20 years. However, technical constrains related to the use of capillary electrophoresis and a recent technological revolution that has impacted other marker types have brought to question the continued use of microsatellites for certain applications. We present a study for improving microsatellite genotyping in ecology using high-throughput sequencing (HTS). This approach entails selection of short markers suitable for HTS, sequencing PCR-amplified microsatellites on an Illumina platform and bioinformatic treatment of the sequence data to obtain multilocus genotypes. It takes advantage of the fact that HTS gives direct access to microsatellite sequences, allowing unambiguous allele identification and enabling automation of the genotyping process through bioinformatics. In addition, the massive parallel sequencing abilities expand the information content of single experimental runs far beyond capillary electrophoresis. We illustrated the method by genotyping brown bear samples amplified with a multiplex PCR of 13 new microsatellite markers and a sex marker. HTS of microsatellites provided accurate individual identification and parentage assignment and resulted in a significant improvement of genotyping success (84%) of faecal degraded DNA and costs reduction compared to capillary electrophoresis. The HTS approach holds vast potential for improving success, accuracy, efficiency and standardization of microsatellite genotyping in ecological and conservation applications, especially those that rely on profiling of low-quantity/quality DNA and on the construction of genetic databases. We discuss and give perspectives for the implementation of the method in the light of the challenges encountered in wildlife studies. © 2016 John Wiley & Sons Ltd.

  8. Strategies for achieving high sequencing accuracy for low diversity samples and avoiding sample bleeding using illumina platform.

    Science.gov (United States)

    Mitra, Abhishek; Skrzypczak, Magdalena; Ginalski, Krzysztof; Rowicka, Maga

    2015-01-01

    Sequencing microRNA, reduced representation sequencing, Hi-C technology and any method requiring the use of in-house barcodes result in sequencing libraries with low initial sequence diversity. Sequencing such data on the Illumina platform typically produces low quality data due to the limitations of the Illumina cluster calling algorithm. Moreover, even in the case of diverse samples, these limitations are causing substantial inaccuracies in multiplexed sample assignment (sample bleeding). Such inaccuracies are unacceptable in clinical applications, and in some other fields (e.g. detection of rare variants). Here, we discuss how both problems with quality of low-diversity samples and sample bleeding are caused by incorrect detection of clusters on the flowcell during initial sequencing cycles. We propose simple software modifications (Long Template Protocol) that overcome this problem. We present experimental results showing that our Long Template Protocol remarkably increases data quality for low diversity samples, as compared with the standard analysis protocol; it also substantially reduces sample bleeding for all samples. For comprehensiveness, we also discuss and compare experimental results from alternative approaches to sequencing low diversity samples. First, we discuss how the low diversity problem, if caused by barcodes, can be avoided altogether at the barcode design stage. Second and third, we present modified guidelines, which are more stringent than the manufacturer's, for mixing low diversity samples with diverse samples and lowering cluster density, which in our experience consistently produces high quality data from low diversity samples. Fourth and fifth, we present rescue strategies that can be applied when sequencing results in low quality data and when there is no more biological material available. In such cases, we propose that the flowcell be re-hybridized and sequenced again using our Long Template Protocol. Alternatively, we discuss how

  9. Strategies for achieving high sequencing accuracy for low diversity samples and avoiding sample bleeding using illumina platform.

    Directory of Open Access Journals (Sweden)

    Abhishek Mitra

    Full Text Available Sequencing microRNA, reduced representation sequencing, Hi-C technology and any method requiring the use of in-house barcodes result in sequencing libraries with low initial sequence diversity. Sequencing such data on the Illumina platform typically produces low quality data due to the limitations of the Illumina cluster calling algorithm. Moreover, even in the case of diverse samples, these limitations are causing substantial inaccuracies in multiplexed sample assignment (sample bleeding. Such inaccuracies are unacceptable in clinical applications, and in some other fields (e.g. detection of rare variants. Here, we discuss how both problems with quality of low-diversity samples and sample bleeding are caused by incorrect detection of clusters on the flowcell during initial sequencing cycles. We propose simple software modifications (Long Template Protocol that overcome this problem. We present experimental results showing that our Long Template Protocol remarkably increases data quality for low diversity samples, as compared with the standard analysis protocol; it also substantially reduces sample bleeding for all samples. For comprehensiveness, we also discuss and compare experimental results from alternative approaches to sequencing low diversity samples. First, we discuss how the low diversity problem, if caused by barcodes, can be avoided altogether at the barcode design stage. Second and third, we present modified guidelines, which are more stringent than the manufacturer's, for mixing low diversity samples with diverse samples and lowering cluster density, which in our experience consistently produces high quality data from low diversity samples. Fourth and fifth, we present rescue strategies that can be applied when sequencing results in low quality data and when there is no more biological material available. In such cases, we propose that the flowcell be re-hybridized and sequenced again using our Long Template Protocol. Alternatively

  10. High-accuracy single-pass InSAR DEM for large-scale flood hazard applications

    Science.gov (United States)

    Schumann, G.; Faherty, D.; Moller, D.

    2017-12-01

    In this study, we used a unique opportunity of the GLISTIN-A (NASA airborne mission designed to characterizing the cryosphere) track to Greenland to acquire a high-resolution InSAR DEM of a large area in the Red River of the North Basin (north of Grand Forks, ND, USA), which is a very flood-vulnerable valley, particularly in spring time due to increased soil moisture content near state of saturation and/or, typical for this region, snowmelt. Having an InSAR DEM that meets flood inundation modeling and mapping requirements comparable to LiDAR, would demonstrate great application potential of new radar technology for national agencies with an operational flood forecasting mandate and also local state governments active in flood event prediction, disaster response and mitigation. Specifically, we derived a bare-earth DEM in SAR geometry by first removing the inherent far range bias related to airborne operation, which at the more typical large-scale DEM resolution of 30 m has a sensor accuracy of plus or minus 2.5 cm. Subsequently, an intelligent classifier based on informed relationships between InSAR height, intensity and correlation was used to distinguish between bare-earth, roads or embankments, buildings and tall vegetation in order to facilitate the creation of a bare-earth DEM that would meet the requirements for accurate floodplain inundation mapping. Using state-of-the-art LiDAR terrain data, we demonstrate that capability by achieving a root mean squared error of approximately 25 cm and further illustrating its applicability to flood modeling.

  11. Improvements in dose calculation accuracy for small off-axis targets in high dose per fraction tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hardcastle, Nicholas; Bayliss, Adam; Wong, Jeannie Hsiu Ding; Rosenfeld, Anatoly B.; Tome, Wolfgang A. [Department of Human Oncology, University of Wisconsin-Madison, WI, 53792 (United States); Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, VIC 3002 (Australia) and Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia); Department of Human Oncology, University of Wisconsin-Madison, WI 53792 (United States); Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia) and Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur (Malaysia); Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia); Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53792 (United States); Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53792 (United States); Einstein Institute of Oncophysics, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461 (United States) and Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia)

    2012-08-15

    Purpose: A recent field safety notice from TomoTherapy detailed the underdosing of small, off-axis targets when receiving high doses per fraction. This is due to angular undersampling in the dose calculation gantry angles. This study evaluates a correction method to reduce the underdosing, to be implemented in the current version (v4.1) of the TomoTherapy treatment planning software. Methods: The correction method, termed 'Super Sampling' involved the tripling of the number of gantry angles from which the dose is calculated during optimization and dose calculation. Radiochromic film was used to measure the dose to small targets at various off-axis distances receiving a minimum of 21 Gy in one fraction. Measurements were also performed for single small targets at the center of the Lucy phantom, using radiochromic film and the dose magnifying glass (DMG). Results: Without super sampling, the peak dose deficit increased from 0% to 18% for a 10 mm target and 0% to 30% for a 5 mm target as off-axis target distances increased from 0 to 16.5 cm. When super sampling was turned on, the dose deficit trend was removed and all peak doses were within 5% of the planned dose. For measurements in the Lucy phantom at 9.7 cm off-axis, the positional and dose magnitude accuracy using super sampling was verified using radiochromic film and the DMG. Conclusions: A correction method implemented in the TomoTherapy treatment planning system which triples the angular sampling of the gantry angles used during optimization and dose calculation removes the underdosing for targets as small as 5 mm diameter, up to 16.5 cm off-axis receiving up to 21 Gy.

  12. Improvements in dose calculation accuracy for small off-axis targets in high dose per fraction tomotherapy

    International Nuclear Information System (INIS)

    Hardcastle, Nicholas; Bayliss, Adam; Wong, Jeannie Hsiu Ding; Rosenfeld, Anatoly B.; Tomé, Wolfgang A.

    2012-01-01

    Purpose: A recent field safety notice from TomoTherapy detailed the underdosing of small, off-axis targets when receiving high doses per fraction. This is due to angular undersampling in the dose calculation gantry angles. This study evaluates a correction method to reduce the underdosing, to be implemented in the current version (v4.1) of the TomoTherapy treatment planning software. Methods: The correction method, termed “Super Sampling” involved the tripling of the number of gantry angles from which the dose is calculated during optimization and dose calculation. Radiochromic film was used to measure the dose to small targets at various off-axis distances receiving a minimum of 21 Gy in one fraction. Measurements were also performed for single small targets at the center of the Lucy phantom, using radiochromic film and the dose magnifying glass (DMG). Results: Without super sampling, the peak dose deficit increased from 0% to 18% for a 10 mm target and 0% to 30% for a 5 mm target as off-axis target distances increased from 0 to 16.5 cm. When super sampling was turned on, the dose deficit trend was removed and all peak doses were within 5% of the planned dose. For measurements in the Lucy phantom at 9.7 cm off-axis, the positional and dose magnitude accuracy using super sampling was verified using radiochromic film and the DMG. Conclusions: A correction method implemented in the TomoTherapy treatment planning system which triples the angular sampling of the gantry angles used during optimization and dose calculation removes the underdosing for targets as small as 5 mm diameter, up to 16.5 cm off-axis receiving up to 21 Gy.

  13. Magnonic interferometric switch for multi-valued logic circuits

    Science.gov (United States)

    Balynsky, Michael; Kozhevnikov, Alexander; Khivintsev, Yuri; Bhowmick, Tonmoy; Gutierrez, David; Chiang, Howard; Dudko, Galina; Filimonov, Yuri; Liu, Guanxiong; Jiang, Chenglong; Balandin, Alexander A.; Lake, Roger; Khitun, Alexander

    2017-01-01

    We investigated a possible use of the magnonic interferometric switches in multi-valued logic circuits. The switch is a three-terminal device consisting of two spin channels where input, control, and output signals are spin waves. Signal modulation is achieved via the interference between the source and gate spin waves. We report experimental data on a micrometer scale prototype based on the Y3Fe2(FeO4)3 structure. The output characteristics are measured at different angles of the bias magnetic field. The On/Off ratio of the prototype exceeds 13 dB at room temperature. Experimental data are complemented by the theoretical analysis and the results of micro magnetic simulations showing spin wave propagation in a micrometer size magnetic junction. We also present the results of numerical modeling illustrating the operation of a nanometer-size switch consisting of just 20 spins in the source-drain channel. The utilization of spin wave interference as a switching mechanism makes it possible to build nanometer-scale logic gates, and minimize energy per operation, which is limited only by the noise margin. The utilization of phase in addition to amplitude for information encoding offers an innovative route towards multi-state logic circuits. We describe possible implementation of the three-value logic circuits based on the magnonic interferometric switches. The advantages and shortcomings inherent in interferometric switches are also discussed.

  14. Robust sparse image reconstruction of radio interferometric observations with PURIFY

    Science.gov (United States)

    Pratley, Luke; McEwen, Jason D.; d'Avezac, Mayeul; Carrillo, Rafael E.; Onose, Alexandru; Wiaux, Yves

    2018-01-01

    Next-generation radio interferometers, such as the Square Kilometre Array, will revolutionize our understanding of the Universe through their unprecedented sensitivity and resolution. However, to realize these goals significant challenges in image and data processing need to be overcome. The standard methods in radio interferometry for reconstructing images, such as CLEAN, have served the community well over the last few decades and have survived largely because they are pragmatic. However, they produce reconstructed interferometric images that are limited in quality and scalability for big data. In this work, we apply and evaluate alternative interferometric reconstruction methods that make use of state-of-the-art sparse image reconstruction algorithms motivated by compressive sensing, which have been implemented in the PURIFY software package. In particular, we implement and apply the proximal alternating direction method of multipliers algorithm presented in a recent article. First, we assess the impact of the interpolation kernel used to perform gridding and degridding on sparse image reconstruction. We find that the Kaiser-Bessel interpolation kernel performs as well as prolate spheroidal wave functions while providing a computational saving and an analytic form. Secondly, we apply PURIFY to real interferometric observations from the Very Large Array and the Australia Telescope Compact Array and find that images recovered by PURIFY are of higher quality than those recovered by CLEAN. Thirdly, we discuss how PURIFY reconstructions exhibit additional advantages over those recovered by CLEAN. The latest version of PURIFY, with developments presented in this work, is made publicly available.

  15. Strategy for high-accuracy-and-precision retrieval of atmospheric methane from the mid-infrared FTIR network

    Directory of Open Access Journals (Sweden)

    R. Sussmann

    2011-09-01

    Full Text Available We present a strategy (MIR-GBM v1.0 for the retrieval of column-averaged dry-air mole fractions of methane (XCH4 with a precision <0.3% (1-σ diurnal variation, 7-min integration and a seasonal bias <0.14% from mid-infrared ground-based solar FTIR measurements of the Network for the Detection of Atmospheric Composition Change (NDACC, comprising 22 FTIR stations. This makes NDACC methane data useful for satellite validation and for the inversion of regional-scale sources and sinks in addition to long-term trend analysis. Such retrievals complement the high accuracy and precision near-infrared observations of the younger Total Carbon Column Observing Network (TCCON with time series dating back 15 years or so before TCCON operations began.

    MIR-GBM v1.0 is using HITRAN 2000 (including the 2001 update release and 3 spectral micro windows (2613.70–2615.40 cm−1, 2835.50–2835.80 cm−1, 2921.00–2921.60 cm−1. A first-order Tikhonov constraint is applied to the state vector given in units of per cent of volume mixing ratio. It is tuned to achieve minimum diurnal variation without damping seasonality. Final quality selection of the retrievals uses a threshold for the goodness of fit (χ2 < 1 as well as for the ratio of root-mean-square spectral noise and information content (<0.15%. Column-averaged dry-air mole fractions are calculated using the retrieved methane profiles and four-times-daily pressure-temperature-humidity profiles from National Center for Environmental Prediction (NCEP interpolated to the time of measurement.

    MIR-GBM v1.0 is the optimum of 24 tested retrieval strategies (8 different spectral micro-window selections, 3 spectroscopic line lists: HITRAN 2000, 2004, 2008. Dominant errors of the non-optimum retrieval strategies are systematic HDO/H2O-CH4 interference errors leading to a seasonal bias up to ≈5%. Therefore interference

  16. Interferometric Imaging and its Application to 4D Imaging

    KAUST Repository

    Sinha, Mrinal

    2018-03-01

    This thesis describes new interferometric imaging methods for migration and waveform inversion. The key idea is to use reflection events from a known reference reflector to ”naturally redatum” the receivers and sources to the reference reflector. Here, ”natural redatuming” is a data-driven process where the redatuming Green’s functions are obtained from the data. Interferometric imaging eliminates the statics associated with the noisy overburden above the reference reflector. To mitigate the defocussing caused by overburden errors I first propose the use of interferometric least-squares migration (ILSM) to estimate the migration image. Here, a known reflector is used as the reference interface for ILSM, and the data are naturally redatumed to this reference interface before imaging. Numerical results on synthetic and field data show that ILSM can significantly reduce the defocussing artifacts in the migration image. Next, I develop a waveform tomography approach for inverting the velocity model by mitigating the velocity errors in the overburden. Unresolved velocity errors in the overburden velocity model can cause conventional full-waveform inversion to get stuck in a local minimum. To resolve this problem, I present interferometric full-waveform inversion (IFWI), where conventional waveform tomography is reformulated so a velocity model is found that minimizes the objective function with an interferometric crosscorrelogram misfit. Numerical examples show that IFWI, compared to FWI, computes a significantly more accurate velocity model in the presence of a nearsurface with unknown velocity anomalies. I use IFWI and ILSM for 4D imaging where seismic data are recorded at different times over the same reservoir. To eliminate the time-varying effects of the near surface both data sets are virtually redatumed to a common reference interface before migration. This largely eliminates the overburden-induced statics errors in both data sets. Results with

  17. High-accuracy and high-sensitivity spectroscopic measurement of dinitrogen pentoxide (N2O5) in an atmospheric simulation chamber using a quantum cascade laser.

    Science.gov (United States)

    Yi, Hongming; Wu, Tao; Lauraguais, Amélie; Semenov, Vladimir; Coeur, Cecile; Cassez, Andy; Fertein, Eric; Gao, Xiaoming; Chen, Weidong

    2017-12-04

    A spectroscopic instrument based on a mid-infrared external cavity quantum cascade laser (EC-QCL) was developed for high-accuracy measurements of dinitrogen pentoxide (N 2 O 5 ) at the ppbv-level. A specific concentration retrieval algorithm was developed to remove, from the broadband absorption spectrum of N 2 O 5 , both etalon fringes resulting from the EC-QCL intrinsic structure and spectral interference lines of H 2 O vapour absorption, which led to a significant improvement in measurement accuracy and detection sensitivity (by a factor of 10), compared to using a traditional algorithm for gas concentration retrieval. The developed EC-QCL-based N 2 O 5 sensing platform was evaluated by real-time tracking N 2 O 5 concentration in its most important nocturnal tropospheric chemical reaction of NO 3 + NO 2 ↔ N 2 O 5 in an atmospheric simulation chamber. Based on an optical absorption path-length of L eff = 70 m, a minimum detection limit of 15 ppbv was achieved with a 25 s integration time and it was down to 3 ppbv in 400 s. The equilibrium rate constant K eq involved in the above chemical reaction was determined with direct concentration measurements using the developed EC-QCL sensing platform, which was in good agreement with the theoretical value deduced from a referenced empirical formula under well controlled experimental conditions. The present work demonstrates the potential and the unique advantage of the use of a modern external cavity quantum cascade laser for applications in direct quantitative measurement of broadband absorption of key molecular species involved in chemical kinetic and climate-change related tropospheric chemistry.

  18. San Francisco Bay Interferometric Bathymetry: Area B

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — High resolution sonar data were collected over ultra-shallow areas of the San Francisco Bay estuary system. Bathymetric and acoustic backscatter data were collected...

  19. Spatial variability in sensitivity of reference crop ET to accuracy of climate data in the Texas High Plains

    Science.gov (United States)

    A detailed sensitivity analysis was conducted to determine the relative effects of measurement errors in climate data input parameters on the accuracy of calculated reference crop evapotranspiration (ET) using the ASCE-EWRI Standardized Reference ET Equation. Data for the period of 1995 to 2008, fro...

  20. Transformation Model with Constraints for High-Accuracy of 2D-3D Building Registration in Aerial Imagery

    Directory of Open Access Journals (Sweden)

    Guoqing Zhou

    2016-06-01

    Full Text Available This paper proposes a novel rigorous transformation model for 2D-3D registration to address the difficult problem of obtaining a sufficient number of well-distributed ground control points (GCPs in urban areas with tall buildings. The proposed model applies two types of geometric constraints, co-planarity and perpendicularity, to the conventional photogrammetric collinearity model. Both types of geometric information are directly obtained from geometric building structures, with which the geometric constraints are automatically created and combined into the conventional transformation model. A test field located in downtown Denver, Colorado, is used to evaluate the accuracy and reliability of the proposed method. The comparison analysis of the accuracy achieved by the proposed method and the conventional method is conducted. Experimental results demonstrated that: (1 the theoretical accuracy of the solved registration parameters can reach 0.47 pixels, whereas the other methods reach only 1.23 and 1.09 pixels; (2 the RMS values of 2D-3D registration achieved by the proposed model are only two pixels along the x and y directions, much smaller than the RMS values of the conventional model, which are approximately 10 pixels along the x and y directions. These results demonstrate that the proposed method is able to significantly improve the accuracy of 2D-3D registration with much fewer GCPs in urban areas with tall buildings.

  1. Continuous assessment of land mapping accuracy at High Resolution from global networks of atmospheric and field observatories -concept and demonstration

    Science.gov (United States)

    Sicard, Pierre; Martin-lauzer, François-regis

    2017-04-01

    In the context of global climate change and adjustment/resilience policies' design and implementation, there is a need not only i. for environmental monitoring, e.g. through a range of Earth Observations (EO) land "products" but ii. for a precise assessment of uncertainties of the aforesaid information that feed environmental decision-making (to be introduced in the EO metadata) and also iii. for a perfect handing of the thresholds which help translate "environment tolerance limits" to match detected EO changes through ecosystem modelling. Uncertainties' insight means precision and accuracy's knowledge and subsequent ability of setting thresholds for change detection systems. Traditionally, the validation of satellite-derived products has taken the form of intensive field campaigns to sanction the introduction of data processors in Payload Data Ground Segments chains. It is marred by logistical challenges and cost issues, reason why it is complemented by specific surveys at ground-based monitoring sites which can provide near-continuous observations at a high temporal resolution (e.g. RadCalNet). Unfortunately, most of the ground-level monitoring sites, in the number of 100th or 1000th, which are part of wider observation networks (e.g. FLUXNET, NEON, IMAGINES) mainly monitor the state of the atmosphere and the radiation exchange at the surface, which are different to the products derived from EO data. In addition they are "point-based" compared to the EO cover to be obtained from Sentinel-2 or Sentinel-3. Yet, data from these networks, processed by spatial extrapolation models, are well-suited to the bottom-up approach and relevant to the validation of vegetation parameters' consistency (e.g. leaf area index, fraction of absorbed photosynthetically active radiation). Consistency means minimal errors on spatial and temporal gradients of EO products. Test of the procedure for land-cover products' consistency assessment with field measurements delivered by worldwide

  2. Improved accuracy of cortical bone mineralization measured by polychromatic microcomputed tomography using a novel high mineral density composite calibration phantom

    International Nuclear Information System (INIS)

    Deuerling, Justin M.; Rudy, David J.; Niebur, Glen L.; Roeder, Ryan K.

    2010-01-01

    Purpose: Microcomputed tomography (micro-CT) is increasingly used as a nondestructive alternative to ashing for measuring bone mineral content. Phantoms are utilized to calibrate the measured x-ray attenuation to discrete levels of mineral density, typically including levels up to 1000 mg HA/cm 3 , which encompasses levels of bone mineral density (BMD) observed in trabecular bone. However, levels of BMD observed in cortical bone and levels of tissue mineral density (TMD) in both cortical and trabecular bone typically exceed 1000 mg HA/cm 3 , requiring extrapolation of the calibration regression, which may result in error. Therefore, the objectives of this study were to investigate (1) the relationship between x-ray attenuation and an expanded range of hydroxyapatite (HA) density in a less attenuating polymer matrix and (2) the effects of the calibration on the accuracy of subsequent measurements of mineralization in human cortical bone specimens. Methods: A novel HA-polymer composite phantom was prepared comprising a less attenuating polymer phase (polyethylene) and an expanded range of HA density (0-1860 mg HA/cm 3 ) inclusive of characteristic levels of BMD in cortical bone or TMD in cortical and trabecular bone. The BMD and TMD of cortical bone specimens measured using the new HA-polymer calibration phantom were compared to measurements using a conventional HA-polymer phantom comprising 0-800 mg HA/cm 3 and the corresponding ash density measurements on the same specimens. Results: The HA-polymer composite phantom exhibited a nonlinear relationship between x-ray attenuation and HA density, rather than the linear relationship typically employed a priori, and obviated the need for extrapolation, when calibrating the measured x-ray attenuation to high levels of mineral density. The BMD and TMD of cortical bone specimens measured using the conventional phantom was significantly lower than the measured ash density by 19% (p<0.001, ANCOVA) and 33% (p<0.05, Tukey's HSD

  3. Development of dynamic 3-D surface profilometry using stroboscopic interferometric measurement and vertical scanning techniques

    Energy Technology Data Exchange (ETDEWEB)

    Fan, K-C [Department of Mechanical Engineering, National Taiwan University, 1, Sec. 4 Roosevelt Rd, Taipei, Taiwan (China); Chen, L-C [Graduate Institute of Automation Technology, National Taipei University of Technology, 1 Sec. 3 Chung-Hsiao East Rd, Taipei, 106, Taiwan (China); Lin, C-D [Department of Mechanical Engineering, National Taiwan University, 1, Sec. 4 Roosevelt Rd, Taipei, Taiwan (China); Chang, Calvin C [Industrial Technology Research Institute, Centre for Measurement Standards, 321 Sec. 2, Kuang Fu Rd, Hsinchu, Taiwan, 300 (China); Kuo, C-F [Industrial Technology Research Institute, Centre for Measurement Standards, 321 Sec. 2, Kuang Fu Rd, Hsinchu, Taiwan, 300 (China); Chou, J-T [Industrial Technology Research Institute, Centre for Measurement Standards, 321 Sec. 2, Kuang Fu Rd, Hsinchu, Taiwan, 300 (China)

    2005-01-01

    The main objective of this technical advance is to provide a single optical interferometric framework and methodology to be capable of delivering both nano-scale static and dynamic surface profilometry. Microscopic interferometry is a powerful technique for static and dynamic characterization of micro (opto) electromechanical systems (M (O) EMS). In view of this need, a microscopic prototype based on white-light stroboscopic interferometry and the white light vertical scanning principle, was developed to achieve dynamic full-field profilometry and characterization of MEMS devices. The system primarily consists of an optical microscope, on which a Mirau interferometric objective embedded with a piezoelectric vertical translator, a high-power LED light module with dual operation modes and light synchronizing electronics unit are integrated. A micro cantilever beam used in AFM was measured to verify the system capability in accurate characterization of dynamic behaviours of the device. The full-field second-mode vibration at a vibratory frequency of 68.60 kHz can be fully characterized and 3-5 nm of vertical measurement resolution as well as tens of micrometers of vertical measurement range can be easily achieved.

  4. Lower frequency companions for the Advanced LIGO gravitational wave interferometric detectors: an observational opportunity?

    International Nuclear Information System (INIS)

    DeSalvo, Riccardo

    2004-01-01

    Recent x-ray and optical observations provide evidence for a population of intermediate mass black holes with masses of tens to thousands of solar masses. Dynamical braking in high stellar density regions may 'catalyze' the inspiral of heavy mass objects down to the million-year time scale. Black-hole binaries, with the masses implied by the observations, will plunge below 100 Hz. It may be technologically possible to build ground-based low frequency gravitational wave interferometric detectors optimized to detect these events and install them next to Advanced LIGO (AdL), within the existing LIGO facilities. This additional interferometer, operated coherently with AdL and Virgo, would greatly enhance the effectiveness of the existing interferometers by generating a wealth of triggers for potentially frequent but otherwise undetectable heavy mass inspirals. AdL would study, at higher frequency, the triggered, ultra-relativistic phases (merging and ringdown) of these inspirals. Comparisons are made between the expected detection performances of AdL in its proposed wide band tuning, as well as AdL in its best low frequency tuning, with a low frequency gravitational wave interferometric detector that is mechanically and optically optimized for operation at the lowest possible frequency. Finally, the synergies of tandem operation of AdL and the proposed low frequency interferometer have been considered

  5. Computational adaptive optics for broadband interferometric tomography of tissues and cells

    Science.gov (United States)

    Adie, Steven G.; Mulligan, Jeffrey A.

    2016-03-01

    Adaptive optics (AO) can shape aberrated optical wavefronts to physically restore the constructive interference needed for high-resolution imaging. With access to the complex optical field, however, many functions of optical hardware can be achieved computationally, including focusing and the compensation of optical aberrations to restore the constructive interference required for diffraction-limited imaging performance. Holography, which employs interferometric detection of the complex optical field, was developed based on this connection between hardware and computational image formation, although this link has only recently been exploited for 3D tomographic imaging in scattering biological tissues. This talk will present the underlying imaging science behind computational image formation with optical coherence tomography (OCT) -- a beam-scanned version of broadband digital holography. Analogous to hardware AO (HAO), we demonstrate computational adaptive optics (CAO) and optimization of the computed pupil correction in 'sensorless mode' (Zernike polynomial corrections with feedback from image metrics) or with the use of 'guide-stars' in the sample. We discuss the concept of an 'isotomic volume' as the volumetric extension of the 'isoplanatic patch' introduced in astronomical AO. Recent CAO results and ongoing work is highlighted to point to the potential biomedical impact of computed broadband interferometric tomography. We also discuss the advantages and disadvantages of HAO vs. CAO for the effective shaping of optical wavefronts, and highlight opportunities for hybrid approaches that synergistically combine the unique advantages of hardware and computational methods for rapid volumetric tomography with cellular resolution.

  6. High-accuracy continuous airborne measurements of greenhouse gases (CO2 and CH4) using the cavity ring-down spectroscopy (CRDS) technique

    NARCIS (Netherlands)

    Chen, H.; Winderlich, J.; Gerbig, C.; Hoefer, A.; Rella, C. W.; Crosson, E. R.; Van Pelt, A. D.; Steinbach, J.; Kolle, O.; Beck, V.; Daube, B. C.; Gottlieb, E. W.; Chow, V. Y.; Santoni, G. W.; Wofsy, S. C.

    2010-01-01

    High-accuracy continuous measurements of greenhouse gases (CO2 and CH4) during the BARCA (Balancao Atmosferico Regional de Carbono na Amazonia) phase B campaign in Brazil in May 2009 were accomplished using a newly available analyzer based on the cavity ring-down spectroscopy (CRDS) technique. This

  7. High accuracy results for the energy levels of the molecular ions H+2, D+2 and HD+, up to J = 2

    International Nuclear Information System (INIS)

    Karr, J Ph; Hilico, L

    2006-01-01

    We present a nonrelativistic calculation of the rotation-vibration levels of the molecular ions H + 2 , D + 2 and HD + , relying on the diagonalization of the exact three-body Hamiltonian in a variational basis. The J = 2 levels are obtained with a very high accuracy of 10 -14 au (for most levels) representing an improvement by five orders of magnitude over previous calculations. The accuracy is also improved for the J = 1 levels of H + 2 and D + 2 with respect to earlier works. Moreover, we have computed the sensitivities of the energy levels with respect to the mass ratios, allowing these levels to be used for metrological purposes

  8. Interferometric Star Tracker for High Precision Pointing, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Optical Physics Company (OPC) proposes to adapt the precision star tracker it is currently developing under several DoD contracts for deep space lasercom beam...

  9. High precision speed measurement by using interferometric techniques

    International Nuclear Information System (INIS)

    Ávila, M A Rodríguez; Valiente, R Ochoa; Trujillo, L A García

    2015-01-01

    In this work we present the experimental realization of speed measurement by the use of a two wave interferometer and digital signal processing techniques. We built an automated Michelson interferometer and using an He-Ne laser and with the use of the Fast Fourier Transform (FFT) and computer algorithms we derived a method for finding the speed of displacement. We report uncertainties in the order of 2-3 μm/s. with the use of this procedure. This brings the potential of another physical variable measurement like distance or pressure by this indirect measurement method. This approach is compared with an ultrasonic Logger Pro ® speed measurement system, and the results are compared between systems

  10. Interferometric measurements of plasma density in high-β plasmas

    International Nuclear Information System (INIS)

    Quinn, W.E.

    1977-01-01

    The coupled-cavity laser interferometer technique is particularly applicable to the measurement of pulsed plasma densities. This technique is based on the fact that if a small fraction of a gas laser's output radiation is reflected into the laser with an external mirror, the intensity of the laser output is modulated. These amplitude or intensity modulations are produced by changes in the laser gain. A rotating corner mirror or an oscillating mirror can be used to produce a continuous feedback modulation of the interferometer which produces a continuous background fringe pattern. The presence of plasma in the outer cavity causes an additional change which results in a phase shift of the regular period of the background fringe pattern. The integral of the plasma density along the line of sight can be evaluated by comparison of the time history of the fringes obtained with and without plasma

  11. High-speed optical coherence tomography by circular interferometric ranging

    Science.gov (United States)

    Siddiqui, Meena; Nam, Ahhyun S.; Tozburun, Serhat; Lippok, Norman; Blatter, Cedric; Vakoc, Benjamin J.

    2018-02-01

    Existing three-dimensional optical imaging methods excel in controlled environments, but are difficult to deploy over large, irregular and dynamic fields. This means that they can be ill-suited for use in areas such as material inspection and medicine. To better address these applications, we developed methods in optical coherence tomography to efficiently interrogate sparse scattering fields, that is, those in which most locations (voxels) do not generate meaningful signal. Frequency comb sources are used to superimpose reflected signals from equispaced locations through optical subsampling. This results in circular ranging, and reduces the number of measurements required to interrogate large volumetric fields. As a result, signal acquisition barriers that have limited speed and field in optical coherence tomography are avoided. With a new ultrafast, time-stretched frequency comb laser design operating with 7.6 MHz to 18.9 MHz repetition rates, we achieved imaging of multi-cm3 fields at up to 7.5 volumes per second.

  12. Stabilizing operation point technique based on the tunable distributed feedback laser for interferometric sensors

    Science.gov (United States)

    Mao, Xuefeng; Zhou, Xinlei; Yu, Qingxu

    2016-02-01

    We describe a stabilizing operation point technique based on the tunable Distributed Feedback (DFB) laser for quadrature demodulation of interferometric sensors. By introducing automatic lock quadrature point and wavelength periodically tuning compensation into an interferometric system, the operation point of interferometric system is stabilized when the system suffers various environmental perturbations. To demonstrate the feasibility of this stabilizing operation point technique, experiments have been performed using a tunable-DFB-laser as light source to interrogate an extrinsic Fabry-Perot interferometric vibration sensor and a diaphragm-based acoustic sensor. Experimental results show that good tracing of Q-point was effectively realized.

  13. CARETS: A prototype regional environmental information system. Volume 6: Cost, accuracy and consistency comparisons of land use maps made from high-altitude aircraft photography and ERTS imagery

    Science.gov (United States)

    Alexander, R. H. (Principal Investigator); Fitzpatrick, K. A.

    1975-01-01

    The author has identified the following significant results. Level 2 land use maps produced at three scales (1:24,000, 1:100,000, and 1:250,000) from high altitude photography were compared with each other and with point data obtained in the field. The same procedures were employed to determine the accuracy of the Level 1 land use maps produced at 1:250,000 from high altitude photography and color composite ERTS imagery. Accuracy of the Level 2 maps was 84.9 percent at 1:24,000, 77.4 percent at 1:100,000 and 73.0 percent at 1:250,000. Accuracy of the Level 1 1:250,000 maps was 76.5 percent for aerial photographs and 69.5 percent for ERTS imagery. The cost of Level 2 land use mapping at 1:24,000 was found to be high ($11.93 per sq km). The cost of mapping at 1:100,000 ($1.75) was about two times as expensive as mapping at 1:250,000 ($.88), and the accuracy increased by only 4.4 percent.

  14. Accurate mass measurements of very short-lived nuclei. Prerequisites for high-accuracy investigations of superallowed β-decays

    International Nuclear Information System (INIS)

    Herfurth, F.; Kellerbauer, A.; Sauvan, E.; Ames, F.; Engels, O.; Audi, G.; Lunney, D.; Beck, D.; Blaum, K.; Kluge, H.J.; Scheidenberger, C.; Sikler, G.; Weber, C.; Bollen, G.; Schwarz, S.; Moore, R.B.; Oinonen, M.

    2002-01-01

    Mass measurements of 34 Ar, 73-78 Kr, and 74,76 Rb were performed with the Penning-trap mass spectrometer ISOLTRAP. Very accurate Q EC -values are needed for the investigations of the Ft-value of 0 + → 0 + nuclear β-decays used to test the standard model predictions for weak interactions. The necessary accuracy on the Q EC -value requires the mass of mother and daughter nuclei to be measured with δm/m ≤ 3 . 10 -8 . For most of the measured nuclides presented here this has been reached. The 34 Ar mass has been measured with a relative accuracy of 1.1 .10 -8 . The Q EC -value of the 34 Ar 0 + → 0 + decay can now be determined with an uncertainty of about 0.01%. Furthermore, 74 Rb is the shortest-lived nuclide ever investigated in a Penning trap. (orig.)

  15. Accuracy of the solution of the transfer equation for a plane layer of high optical thickness with strongly anisotropic scattering

    International Nuclear Information System (INIS)

    Konovalov, N.V.

    The accuracy of the calculation of the characteristics of a radiation field in a plane layer is investigated by solving the transfer equation in dependence on the error in the specification of the scattering indicatrix. It is shown that a small error in the specification of the indicatrix can lead to a large error in the solution at large optical depths. An estimate is given for the region of optical thicknesses for which the emission field can be determined with sufficient degree of accuracy from the transfer equation with a known error in the specification of the indicatrix. For an estimation of the error involved in various numerical methods, and also for a determination of the region of their applicability, the results of calculations of problems with strongly anisotropic indicatrix are given

  16. Geometric Accuracy Investigations of SEVIRI High Resolution Visible (HRV Level 1.5 Imagery

    Directory of Open Access Journals (Sweden)

    Sultan Kocaman Aksakal

    2013-05-01

    Full Text Available GCOS (Global Climate Observing System is a long-term program for monitoring the climate, detecting the changes, and assessing their impacts. Remote sensing techniques are being increasingly used for climate-related measurements. Imagery of the SEVIRI instrument on board of the European geostationary satellites Meteosat-8 and Meteosat-9 are often used for the estimation of essential climate variables. In a joint project between the Swiss GCOS Office and ETH Zurich, geometric accuracy and temporal stability of 1-km resolution HRV channel imagery of SEVIRI have been evaluated over Switzerland. A set of tools and algorithms has been developed for the investigations. Statistical analysis and blunder detection have been integrated in the process for robust evaluation. The relative accuracy is evaluated by tracking large numbers of feature points in consecutive HRV images taken at 15-minute intervals. For the absolute accuracy evaluation, lakes in Switzerland and surroundings are used as reference. 20 lakes digitized from Landsat orthophotos are transformed into HRV images and matched via 2D translation terms at sub-pixel level. The algorithms are tested using HRV images taken on 24 days in 2008 (2 days per month. The results show that 2D shifts that are up to 8 pixels are present both in relative and absolute terms.

  17. Interferometric Reflectance Imaging Sensor (IRIS—A Platform Technology for Multiplexed Diagnostics and Digital Detection

    Directory of Open Access Journals (Sweden)

    Oguzhan Avci

    2015-07-01

    Full Text Available Over the last decade, the growing need in disease diagnostics has stimulated rapid development of new technologies with unprecedented capabilities. Recent emerging infectious diseases and epidemics have revealed the shortcomings of existing diagnostics tools, and the necessity for further improvements. Optical biosensors can lay the foundations for future generation diagnostics by providing means to detect biomarkers in a highly sensitive, specific, quantitative and multiplexed fashion. Here, we review an optical sensing technology, Interferometric Reflectance Imaging Sensor (IRIS, and the relevant features of this multifunctional platform for quantitative, label-free and dynamic detection. We discuss two distinct modalities for IRIS: (i low-magnification (ensemble biomolecular mass measurements and (ii high-magnification (digital detection of individual nanoparticles along with their applications, including label-free detection of multiplexed protein chips, measurement of single nucleotide polymorphism, quantification of transcription factor DNA binding, and high sensitivity digital sensing and characterization of nanoparticles and viruses.

  18. Integrating gravimetric and interferometric synthetic aperture radar data for enhancing reservoir history matching of carbonate gas and volatile oil reservoirs

    KAUST Repository

    Katterbauer, Klemens

    2016-08-25

    Reservoir history matching is assuming a critical role in understanding reservoir characteristics, tracking water fronts, and forecasting production. While production data have been incorporated for matching reservoir production levels and estimating critical reservoir parameters, the sparse spatial nature of this dataset limits the efficiency of the history matching process. Recently, gravimetry techniques have significantly advanced to the point of providing measurement accuracy in the microgal range and consequently can be used for the tracking of gas displacement caused by water influx. While gravity measurements provide information on subsurface density changes, i.e., the composition of the reservoir, these data do only yield marginal information about temporal displacements of oil and inflowing water. We propose to complement gravimetric data with interferometric synthetic aperture radar surface deformation data to exploit the strong pressure deformation relationship for enhancing fluid flow direction forecasts. We have developed an ensemble Kalman-filter-based history matching framework for gas, gas condensate, and volatile oil reservoirs, which synergizes time-lapse gravity and interferometric synthetic aperture radar data for improved reservoir management and reservoir forecasts. Based on a dual state-parameter estimation algorithm separating the estimation of static reservoir parameters from the dynamic reservoir parameters, our numerical experiments demonstrate that history matching gravity measurements allow monitoring the density changes caused by oil-gas phase transition and water influx to determine the saturation levels, whereas the interferometric synthetic aperture radar measurements help to improve the forecasts of hydrocarbon production and water displacement directions. The reservoir estimates resulting from the dual filtering scheme are on average 20%-40% better than those from the joint estimation scheme, but require about a 30% increase in

  19. Fiber-linked interferometric pressure sensor

    Science.gov (United States)

    Beheim, G.; Fritsch, K.; Poorman, R. N.

    1987-01-01

    A fiber-optic pressure sensor is described which uses a diaphragm to modulate the mirror separation of a Fabry-Perot cavity (the sensing cavity). A multimode optical fiber delivers broadband light to the sensing cavity and returns the spectrally modulated light which the cavity reflects. The sensor's output spectrum is analyzed using a tunable Fabry-Perot cavity (the reference cavity) to determine the mismatch in the mirror separations of the two cavities. An electronic servo control uses this result to cause the mirror separation of the reference cavity to equal that of the sensing cavity. The displacement of the pressure-sensing diaphragm is then obtained by measuring the capacitance of the reference cavity's metal-coated mirrors. Relative to other fiber-optic sensors, an important advantage of this instrument is its high immunity to the effects of variations in both the transmissivity of the fiber link and the wavelength of the optical source.

  20. Interferometric direction finding with a metamaterial detector

    Energy Technology Data Exchange (ETDEWEB)

    Venkatesh, Suresh; Schurig, David, E-mail: david.schurig@utah.edu [Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112 (United States); Shrekenhamer, David; Padilla, Willie [Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467 (United States); Xu, Wangren; Sonkusale, Sameer [Department of Electrical and Computer Engineering, Tufts University, Medford, Massachusetts 02155 (United States)

    2013-12-16

    We present measurements and analysis demonstrating useful direction finding of sources in the S band (2–4 GHz) using a metamaterial detector. An augmented metamaterial absorber that supports magnitude and phase measurement of the incident electric field, within each unit cell, is described. The metamaterial is implemented in a commercial printed circuit board process with off-board back-end electronics. We also discuss on-board back-end implementation strategies. Direction finding performance is analyzed for the fabricated metamaterial detector using simulated data and the standard algorithm, MUtiple SIgnal Classification. The performance of this complete system is characterized by its angular resolution as a function of radiation density at the detector. Sources with power outputs typical of mobile communication devices can be resolved at kilometer distances with sub-degree resolution and high frame rates.

  1. DETECTION OF FAST TRANSIENTS WITH RADIO INTERFEROMETRIC ARRAYS

    International Nuclear Information System (INIS)

    Bhat, N. D. R.; Chengalur, J. N.; Gupta, Y.; Prasad, J.; Roy, J.; Kudale, S. S.; Cox, P. J.; Bailes, M.; Burke-Spolaor, S.; Van Straten, W.

    2013-01-01

    Next-generation radio arrays, including the Square Kilometre Array (SKA) and its pathfinders, will open up new avenues for exciting transient science at radio wavelengths. Their innovative designs, comprising a large number of small elements, pose several challenges in digital processing and optimal observing strategies. The Giant Metre-wave Radio Telescope (GMRT) presents an excellent test-bed for developing and validating suitable observing modes and strategies for transient experiments with future arrays. Here we describe the first phase of the ongoing development of a transient detection system for GMRT that is planned to eventually function in a commensal mode with other observing programs. It capitalizes on the GMRT's interferometric and sub-array capabilities, and the versatility of a new software backend. We outline considerations in the plan and design of transient exploration programs with interferometric arrays, and describe a pilot survey that was undertaken to aid in the development of algorithms and associated analysis software. This survey was conducted at 325 and 610 MHz, and covered 360 deg 2 of the sky with short dwell times. It provides large volumes of real data that can be used to test the efficacies of various algorithms and observing strategies applicable for transient detection. We present examples that illustrate the methodologies of detecting short-duration transients, including the use of sub-arrays for higher resilience to spurious events of terrestrial origin, localization of candidate events via imaging, and the use of a phased array for improved signal detection and confirmation. In addition to demonstrating applications of interferometric arrays for fast transient exploration, our efforts mark important steps in the roadmap toward SKA-era science.

  2. Detection of Fast Transients with Radio Interferometric Arrays

    Science.gov (United States)

    Bhat, N. D. R.; Chengalur, J. N.; Cox, P. J.; Gupta, Y.; Prasad, J.; Roy, J.; Bailes, M.; Burke-Spolaor, S.; Kudale, S. S.; van Straten, W.

    2013-05-01

    Next-generation radio arrays, including the Square Kilometre Array (SKA) and its pathfinders, will open up new avenues for exciting transient science at radio wavelengths. Their innovative designs, comprising a large number of small elements, pose several challenges in digital processing and optimal observing strategies. The Giant Metre-wave Radio Telescope (GMRT) presents an excellent test-bed for developing and validating suitable observing modes and strategies for transient experiments with future arrays. Here we describe the first phase of the ongoing development of a transient detection system for GMRT that is planned to eventually function in a commensal mode with other observing programs. It capitalizes on the GMRT's interferometric and sub-array capabilities, and the versatility of a new software backend. We outline considerations in the plan and design of transient exploration programs with interferometric arrays, and describe a pilot survey that was undertaken to aid in the development of algorithms and associated analysis software. This survey was conducted at 325 and 610 MHz, and covered 360 deg2 of the sky with short dwell times. It provides large volumes of real data that can be used to test the efficacies of various algorithms and observing strategies applicable for transient detection. We present examples that illustrate the methodologies of detecting short-duration transients, including the use of sub-arrays for higher resilience to spurious events of terrestrial origin, localization of candidate events via imaging, and the use of a phased array for improved signal detection and confirmation. In addition to demonstrating applications of interferometric arrays for fast transient exploration, our efforts mark important steps in the roadmap toward SKA-era science.

  3. Cost-effective improvements of a rotating platform by integration of a high-accuracy inclinometer and encoders for attitude evaluation

    International Nuclear Information System (INIS)

    Wen, Chenyang; He, Shengyang; Hu, Peida; Bu, Changgen

    2017-01-01

    Attitude heading reference systems (AHRSs) based on micro-electromechanical system (MEMS) inertial sensors are widely used because of their low cost, light weight, and low power. However, low-cost AHRSs suffer from large inertial sensor errors. Therefore, experimental performance evaluation of MEMS-based AHRSs after system implementation is necessary. High-accuracy turntables can be used to verify the performance of MEMS-based AHRSs indoors, but they are expensive and unsuitable for outdoor tests. This study developed a low-cost two-axis rotating platform for indoor and outdoor attitude determination. A high-accuracy inclinometer and encoders were integrated into the platform to improve the achievable attitude test accuracy. An attitude error compensation method was proposed to calibrate the initial attitude errors caused by the movements and misalignment angles of the platform. The proposed attitude error determination method was examined through rotating experiments, which showed that the standard deviations of the pitch and roll errors were 0.050° and 0.090°, respectively. The pitch and roll errors both decreased to 0.024° when the proposed attitude error determination method was used. This decrease validates the effectiveness of the compensation method. Experimental results demonstrated that the integration of the inclinometer and encoders improved the performance of the low-cost, two-axis, rotating platform in terms of attitude accuracy. (paper)

  4. Imaging Stars by Performing Full-Stokes Optical Interferometric Polarimetry

    Directory of Open Access Journals (Sweden)

    Nicholas M. Elias II

    2012-03-01

    Full Text Available Optical interferometry and polarimetry have separately provided new insights into stellar astronomy, especially in the fields of fundamental parameters and atmospheric models. We present: scientific justifications for “full-Stokes” optical interferometric polarimetry (OIP; updated instrument requirements; preliminary beam combiner designs; polarimeter design; end-to-end OIP data reduction; and realistic reimaged full-Stokes models of Be stars with a suitable number of telescopes plus noise sources. All of this work represents preliminary research to construct an OIP beam combiner.

  5. Multi-Wavelength Interferometric Observations of YSO Disks

    Science.gov (United States)

    Ragland, Sam; Akeson, R.; Armandroff, T.; Colavita, M.; Cotton, W.; Danchi, W.; Hillenbrand, L.; Millan-Gabet, R.; Ridgway, S. T.; Traub, W.; Wizinowich, P.

    2010-01-01

    We initiated a multi-color interferometric study of YSO disks in the K, L and N bands using the Keck Interferometer. The initial results on two Herbig Ae/Be stars will be presented. Our observations are sensitive to the radial distribution of temperature in the inner region of the YSO disks. The geometric models show that the apparent size increases linearly with wavelength, suggesting that the disk is extended with a temperature gradient. We will discuss our results in conjunction with the previous measurements of these targets.

  6. Interferometric full-waveform inversion of time-lapse data

    KAUST Repository

    Sinha, Mrinal

    2017-08-17

    One of the key challenges associated with time-lapse surveys is ensuring the repeatability between the baseline and monitor surveys. Non-repeatability between the surveys is caused by varying environmental conditions over the course of different surveys. To overcome this challenge, we propose the use of interferometric full waveform inversion (IFWI) for inverting the velocity model from data recorded by baseline and monitor surveys. A known reflector is used as the reference reflector for IFWI, and the data are naturally redatumed to this reference reflector using natural reflections as the redatuming operator. This natural redatuming mitigates the artifacts introduced by the repeatability errors that originate above the reference reflector.

  7. New orbital elements of 5 interferometric double stars

    Directory of Open Access Journals (Sweden)

    Olević D.

    1999-01-01

    Full Text Available In this paper, for the first time, are presented elliptical and Thiel- Innes orbitatal elements for the following interferometric pairs: WDS 00416+2438 = WRH, WDS 03271+1845 = CHARA 10, WDS 04044+2406 = McA 13 Aa, WDS 17095+4047 = McA 45 and WDS 23019+4219 = o And Aa. For the pairs WDS 03271+1845 = CHARA 10 andWDS 04044+2406 = McA 13 Aa are calculated total masses and dynamical parallaxes which are compared with corresponding Hipparcos parallaxes.

  8. Broadband infrared beam splitter for spaceborne interferometric infrared sounder.

    Science.gov (United States)

    Yu, Tianyan; Liu, Dingquan; Qin, Yang

    2014-10-01

    A broadband infrared beam splitter (BS) on ZnSe substrate used for the spaceborne interferometric infrared sounder (SIIRS) is studied in the spectral range of 4.44-15 μm. Both broadband antireflection coating and broadband beam-splitter coating in this BS are designed and tested. To optimize the optical properties and the stability of the BS, suitable infrared materials were selected, and improved deposition techniques were applied. The designed structures matched experimental data well, and the properties of the BS met the application specification of SIIRS.

  9. Very high precision and accuracy analysis of triple isotopic ratios of water. A critical instrumentation comparison study.

    Science.gov (United States)

    Gkinis, Vasileios; Holme, Christian; Morris, Valerie; Thayer, Abigail Grace; Vaughn, Bruce; Kjaer, Helle Astrid; Vallelonga, Paul; Simonsen, Marius; Jensen, Camilla Marie; Svensson, Anders; Maffrezzoli, Niccolo; Vinther, Bo; Dallmayr, Remi

    2017-04-01

    We present a performance comparison study between two state of the art Cavity Ring Down Spectrometers (Picarro L2310-i, L2140-i). The comparison took place during the Continuous Flow Analysis (CFA) campaign for the measurement of the Renland ice core, over a period of three months. Instant and complete vaporisation of the ice core melt stream, as well as of in-house water reference materials is achieved by accurate control of microflows of liquid into a homemade calibration system by following simple principles of the Hagen-Poiseuille law. Both instruments share the same vaporisation unit in a configuration that minimises sample preparation discrepancies between the two analyses. We describe our SMOW-SLAP calibration and measurement protocols for such a CFA application and present quality control metrics acquired during the full period of the campaign on a daily basis. The results indicate an unprecedented performance for all 3 isotopic ratios (δ2H, δ17O, δ18O ) in terms of precision, accuracy and resolution. We also comment on the precision and accuracy of the second order excess parameters of HD16O and H217O over H218O (Dxs, Δ17O ). To our knowledge these are the first reported CFA measurements at this level of precision and accuracy for all three isotopic ratios. Differences on the performance of the two instruments are carefully assessed during the measurement and reported here. Our quality control protocols extend to the area of low water mixing ratios, a regime in which often atmospheric vapour measurements take place and Cavity Ring Down Analysers show a poorer performance due to the lower signal to noise ratios. We address such issues and propose calibration protocols from which water vapour isotopic analyses can benefit from.

  10. Mildronate (Meldonium) in professional sports - monitoring doping control urine samples using hydrophilic interaction liquid chromatography - high resolution/high accuracy mass spectrometry.

    Science.gov (United States)

    Görgens, Christian; Guddat, Sven; Dib, Josef; Geyer, Hans; Schänzer, Wilhelm; Thevis, Mario

    2015-01-01

    To date, substances such as Mildronate (Meldonium) are not on the radar of anti-doping laboratories as the compound is not explicitly classified as prohibited. However, the anti-ischemic drug Mildronate demonstrates an increase in endurance performance of athletes, improved rehabilitation after exercise, protection against stress, and enhanced activations of central nervous system (CNS) functions. In the present study, the existing evidence of Mildronate's usage in sport, which is arguably not (exclusively) based on medicinal reasons, is corroborated by unequivocal analytical data allowing the estimation of the prevalence and extent of misuse in professional sports. Such data are vital to support decision-making processes, particularly regarding the ban on drugs in sport. Due to the growing body of evidence (black market products and athlete statements) concerning its misuse in sport, adequate test methods for the reliable identification of Mildronate are required, especially since the substance has been added to the 2015 World Anti-Doping Agency (WADA) monitoring program. In the present study, two approaches were established using an in-house synthesized labelled internal standard (Mildronate-D3 ). One aimed at the implementation of the analyte into routine doping control screening methods to enable its monitoring at the lowest possible additional workload for the laboratory, and another that is appropriate for the peculiar specifics of the analyte, allowing the unequivocal confirmation of findings using hydrophilic interaction liquid chromatography-high resolution/high accuracy mass spectrometry (HILIC-HRMS). Here, according to applicable regulations in sports drug testing, a full qualitative validation was conducted. The assay demonstrated good specificity, robustness (rRT=0.3%), precision (intra-day: 7.0-8.4%; inter-day: 9.9-12.9%), excellent linearity (R>0.99) and an adequate lower limit of detection (<10 ng/mL). Copyright © 2015 John Wiley & Sons, Ltd.

  11. Mildronate (Meldonium) in professional sports – monitoring doping control urine samples using hydrophilic interaction liquid chromatography – high resolution/high accuracy mass spectrometry

    Science.gov (United States)

    Görgens, Christian; Dib, Josef; Geyer, Hans; Schänzer, Wilhelm; Thevis, Mario

    2015-01-01

    To date, substances such as Mildronate (Meldonium) are not on the radar of anti‐doping laboratories as the compound is not explicitly classified as prohibited. However, the anti‐ischemic drug Mildronate demonstrates an increase in endurance performance of athletes, improved rehabilitation after exercise, protection against stress, and enhanced activations of central nervous system (CNS) functions. In the present study, the existing evidence of Mildronate's usage in sport, which is arguably not (exclusively) based on medicinal reasons, is corroborated by unequivocal analytical data allowing the estimation of the prevalence and extent of misuse in professional sports. Such data are vital to support decision‐making processes, particularly regarding the ban on drugs in sport. Due to the growing body of evidence (black market products and athlete statements) concerning its misuse in sport, adequate test methods for the reliable identification of Mildronate are required, especially since the substance has been added to the 2015 World Anti‐Doping Agency (WADA) monitoring program. In the present study, two approaches were established using an in‐house synthesized labelled internal standard (Mildronate‐D3). One aimed at the implementation of the analyte into routine doping control screening methods to enable its monitoring at the lowest possible additional workload for the laboratory, and another that is appropriate for the peculiar specifics of the analyte, allowing the unequivocal confirmation of findings using hydrophilic interaction liquid chromatography‐high resolution/high accuracy mass spectrometry (HILIC‐HRMS). Here, according to applicable regulations in sports drug testing, a full qualitative validation was conducted. The assay demonstrated good specificity, robustness (rRT=0.3%), precision (intra‐day: 7.0–8.4%; inter‐day: 9.9–12.9%), excellent linearity (R>0.99) and an adequate lower limit of detection (<10 ng/mL). © 2015 The Authors

  12. Mid-infrared interferometric variability of DG Tauri: Implications for the inner-disk structure

    Science.gov (United States)

    Varga, J.; Gabányi, K. É.; Ábrahám, P.; Chen, L.; Kóspál, Á.; Menu, J.; Ratzka, Th.; van Boekel, R.; Dullemond, C. P.; Henning, Th.; Jaffe, W.; Juhász, A.; Moór, A.; Mosoni, L.; Sipos, N.

    2017-08-01

    Context. DG Tau is a low-mass pre-main sequence star, whose strongly accreting protoplanetary disk exhibits a so-far enigmatic behavior: its mid-infrared thermal emission is strongly time-variable, even turning the 10 μm silicate feature from emission to absorption temporarily. Aims: We look for the reason for the spectral variability at high spatial resolution and at multiple epochs. Methods: Infrared interferometry can spatially resolve the thermal emission of the circumstellar disk, also giving information about dust processing. We study the temporal variability of the mid-infrared interferometric signal, observed with the VLTI/MIDI instrument at six epochs between 2011 and 2014. We fit a geometric disk model to the observed interferometric signal to obtain spatial information about the disk. We also model the mid-infrared spectra by template fitting to characterize the profile and time dependence of the silicate emission. We use physically motivated radiative transfer modeling to interpret the mid-infrared interferometric spectra. Results: The inner disk (r 1-3 au) spectra show a crystalline silicate feature in emission, similar to the spectra of comet Hale-Bopp. The striking difference between the inner and outer disk spectral feature is highly unusual among T Tauri stars. The mid-infrared variability is dominated by the outer disk. The strength of the silicate feature changed by more than a factor of two. Between 2011 and 2014 the half-light radius of the mid-infrared-emitting region decreased from 1.15 to 0.7 au. Conclusions: For the origin of the absorption we discuss four possible explanations: a cold obscuring envelope, an accretion heated inner disk, a temperature inversion on the disk surface and a misaligned inner geometry. The silicate emission in the outer disk can be explained by dusty material high above the disk plane, whose mass can change with time, possibly due to turbulence in the disk. Based on observations made with the ESO Very Large

  13. Probe-level linear model fitting and mixture modeling results in high accuracy detection of differential gene expression

    Directory of Open Access Journals (Sweden)

    Lemieux Sébastien

    2006-08-01

    Full Text Available Abstract Background The identification of differentially expressed genes (DEGs from Affymetrix GeneChips arrays is currently done by first computing expression levels from the low-level probe intensities, then deriving significance by comparing these expression levels between conditions. The proposed PL-LM (Probe-Level Linear Model method implements a linear model applied on the probe-level data to directly estimate the treatment effect. A finite mixture of Gaussian components is then used to identify DEGs using the coefficients estimated by the linear model. This approach can readily be applied to experimental design with or without replication. Results On a wholly defined dataset, the PL-LM method was able to identify 75% of the differentially expressed genes within 10% of false positives. This accuracy was achieved both using the three replicates per conditions available in the dataset and using only one replicate per condition. Conclusion The method achieves, on this dataset, a higher accuracy than the best set of tools identified by the authors of the dataset, and does so using only one replicate per condition.

  14. Quadrature Errors and DC Offsets Calibration of Analog Complex Cross-Correlator for Interferometric Passive Millimeter-Wave Imaging Applications

    Directory of Open Access Journals (Sweden)

    Chao Wang

    2018-02-01

    Full Text Available The design and calibration of the cross-correlator are crucial issues for interferometric imaging systems. In this paper, an analog complex cross-correlator with output DC offsets and amplitudes calibration capability is proposed for interferometric passive millimeter-wave security sensing applications. By employing digital potentiometers in the low frequency amplification circuits of the correlator, the outputs characteristics of the correlator could be digitally controlled. A measurement system and a corresponding calibration scheme were developed in order to eliminate the output DC offsets and the quadrature amplitude error between the in-phase and the quadrature correlating subunits of the complex correlator. By using vector modulators to provide phase controllable correlated noise signals, the measurement system was capable of obtaining the output correlation circle of the correlator. When injected with −18 dBm correlated noise signals, the calibrated quadrature amplitude error was 0.041 dB and the calibrated DC offsets were under 26 mV, which was only 7.1% of the uncalibrated value. Furthermore, we also described a quadrature errors calibration algorithm in order to estimate the quadrature phase error and in order to improve the output phase accuracy of the correlator. After applying this calibration, we were able to reduce the output phase error of the correlator to 0.3°.

  15. A study on low-cost, high-accuracy, and real-time stereo vision algorithms for UAV power line inspection

    Science.gov (United States)

    Wang, Hongyu; Zhang, Baomin; Zhao, Xun; Li, Cong; Lu, Cunyue

    2018-04-01

    Conventional stereo vision algorithms suffer from high levels of hardware resource utilization due to algorithm complexity, or poor levels of accuracy caused by inadequacies in the matching algorithm. To address these issues, we have proposed a stereo range-finding technique that produces an excellent balance between cost, matching accuracy and real-time performance, for power line inspection using UAV. This was achieved through the introduction of a special image preprocessing algorithm and a weighted local stereo matching algorithm, as well as the design of a corresponding hardware architecture. Stereo vision systems based on this technique have a lower level of resource usage and also a higher level of matching accuracy following hardware acceleration. To validate the effectiveness of our technique, a stereo vision system based on our improved algorithms were implemented using the Spartan 6 FPGA. In comparative experiments, it was shown that the system using the improved algorithms outperformed the system based on the unimproved algorithms, in terms of resource utilization and matching accuracy. In particular, Block RAM usage was reduced by 19%, and the improved system was also able to output range-finding data in real time.

  16. A novel lightweight Fizeau infrared interferometric imaging system

    Science.gov (United States)

    Hope, Douglas A.; Hart, Michael; Warner, Steve; Durney, Oli; Romeo, Robert

    2016-05-01

    Aperture synthesis imaging techniques using an interferometer provide a means to achieve imagery with spatial resolution equivalent to a conventional filled aperture telescope at a significantly reduced size, weight and cost, an important implication for air- and space-borne persistent observing platforms. These concepts have been realized in SIRII (Space-based IR-imaging interferometer), a new light-weight, compact SWIR and MWIR imaging interferometer designed for space-based surveillance. The sensor design is configured as a six-element Fizeau interferometer; it is scalable, light-weight, and uses structural components and main optics made of carbon fiber replicated polymer (CFRP) that are easy to fabricate and inexpensive. A three-element prototype of the SIRII imager has been constructed. The optics, detectors, and interferometric signal processing principles draw on experience developed in ground-based astronomical applications designed to yield the highest sensitivity and resolution with cost-effective optical solutions. SIRII is being designed for technical intelligence from geo-stationary orbit. It has an instantaneous 6 x 6 mrad FOV and the ability to rapidly scan a 6x6 deg FOV, with a minimal SNR. The interferometric design can be scaled to larger equivalent filled aperture, while minimizing weight and costs when compared to a filled aperture telescope with equivalent resolution. This scalability in SIRII allows it address a range of IR-imaging scenarios.

  17. Super-virtual interferometric diffractions as guide stars

    KAUST Repository

    Dai, Wei

    2011-01-01

    A significant problem in seismic imaging is seismically seeing below salt structures: large velocity contrasts and the irregular geometry of the salt-sediment interface strongly defocus both the downgoing and upgoing seismic wavefields. This can result in severely defocused migration images so as to seismically render some subsalt reserves invisible. The potential cure is a good estimate of the subsalt and salt velocity distributions, but that is also the problem: severe velocity contrasts prevent the appearance of coherent subsalt reflections in the surface records so that MVA or tomographic methods can become ineffective. We now present an interferometric method for extracting the diffraction signals that emanate from diffractors, also denoted as seismic guide stars. The signal-to-noise ratio of these interferometric diffractions is enhanced by N, where N is the number of source points coincident with the receiver points. Thus, diffractions from subsalt guide stars can then be rendered visible and so can be used for velocity analysis, migration, and focusing of subsalt reflections. Both synthetic and field data records are used to demonstrate the benefits and limitations of this method. © 2011 Society of Exploration Geophysicists.

  18. a High Precision dem Extraction Method Based on Insar Data

    Science.gov (United States)

    Wang, Xinshuang; Liu, Lingling; Shi, Xiaoliang; Huang, Xitao; Geng, Wei

    2018-04-01

    In the 13th Five-Year Plan for Geoinformatics Business, it is proposed that the new InSAR technology should be applied to surveying and mapping production, which will become the innovation driving force of geoinformatics industry. This paper will study closely around the new outline of surveying and mapping and then achieve the TerraSAR/TanDEM data of Bin County in Shaanxi Province in X band. The studying steps are as follows; Firstly, the baseline is estimated from the orbital data; Secondly, the interferometric pairs of SAR image are accurately registered; Thirdly, the interferogram is generated; Fourth, the interferometric correlation information is estimated and the flat-earth phase is removed. In order to solve the phase noise and the discontinuity phase existing in the interferometric image of phase, a GAMMA adaptive filtering method is adopted. Aiming at the "hole" problem of missing data in low coherent area, the interpolation method of low coherent area mask is used to assist the phase unwrapping. Then, the accuracy of the interferometric baseline is estimated from the ground control points. Finally, 1 : 50000 DEM is generated, and the existing DEM data is used to verify the accuracy through statistical analysis. The research results show that the improved InSAR data processing method in this paper can obtain the high-precision DEM of the study area, exactly the same with the topography of reference DEM. The R2 can reach to 0.9648, showing a strong positive correlation.

  19. Performance enhancement of low-cost, high-accuracy, state estimation for vehicle collision prevention system using ANFIS

    Science.gov (United States)

    Saadeddin, Kamal; Abdel-Hafez, Mamoun F.; Jaradat, Mohammad A.; Jarrah, Mohammad Amin

    2013-12-01

    In this paper, a low-cost navigation system that fuses the measurements of the inertial navigation system (INS) and the global positioning system (GPS) receiver is developed. First, the system's dynamics are obtained based on a vehicle's kinematic model. Second, the INS and GPS measurements are fused using an extended Kalman filter (EKF) approach. Subsequently, an artificial intelligence based approach for the fusion of INS/GPS measurements is developed based on an Input-Delayed Adaptive Neuro-Fuzzy Inference System (IDANFIS). Experimental tests are conducted to demonstrate the performance of the two sensor fusion approaches. It is found that the use of the proposed IDANFIS approach achieves a reduction in the integration development time and an improvement in the estimation accuracy of the vehicle's position and velocity compared to the EKF based approach.

  20. New high accuracy super stable alternating direction implicit methods for two and three dimensional hyperbolic damped wave equations

    Directory of Open Access Journals (Sweden)

    R.K. Mohanty

    2014-01-01

    Full Text Available In this paper, we report new three level implicit super stable methods of order two in time and four in space for the solution of hyperbolic damped wave equations in one, two and three space dimensions subject to given appropriate initial and Dirichlet boundary conditions. We use uniform grid points both in time and space directions. Our methods behave like fourth order accurate, when grid size in time-direction is directly proportional to the square of grid size in space-direction. The proposed methods are super stable. The resulting system of algebraic equations is solved by the Gauss elimination method. We discuss new alternating direction implicit (ADI methods for two and three dimensional problems. Numerical results and the graphical representation of numerical solution are presented to illustrate the accuracy of the proposed methods.

  1. Secure space-to-space interferometric communications and its nexus to the physics of quantum entanglement

    Science.gov (United States)

    Duarte, F. J.

    2016-12-01

    The history of the probability amplitude equation | ψ > = ( | x , y > - | y , x > ) applicable to quanta pairs, propagating in different directions with entangled polarizations, is reviewed and traced back to the 1947-1949 period. The interferometric Dirac foundations common to | ψ > = ( | x , y > - | y , x > ) and the generalized N-slit interferometric equation, for indistinguishable quanta, are also described. The results from a series of experiments on N-slit laser interferometers, with intra interferometric propagation paths up to 527 m, are reviewed. Particular attention is given to explain the generation of interferometric characters, for secure space-to-space communications, which immediately collapse on attempts of interception. The design of a low divergence N-slit laser interferometer for low Earth orbit-low Earth orbit (LEO-LEO), and LEO-geostationary Earth orbit (LEO-GEO), secure interferometric communications is described and a weight assessment is provided.

  2. Diagnostic accuracy of magnetic resonance imaging techniques for treatment response evaluation in patients with high-grade glioma, a systematic review and meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Dijken, Bart R.J. van [University of Groningen, University Medical Center Groningen Department of Radiology, Groningen (Netherlands); Laar, Peter Jan van; Hoorn, Anouk van der [University of Groningen, University Medical Center Groningen Department of Radiology, Groningen (Netherlands); University of Groningen, University Medical Center Groningen, Center for Medical Imaging-North East Netherlands, Groningen (Netherlands); Holtman, Gea A. [University of Groningen, University Medical Center Groningen, Department of General Practice, Groningen (Netherlands)

    2017-10-15

    Treatment response assessment in high-grade gliomas uses contrast enhanced T1-weighted MRI, but is unreliable. Novel advanced MRI techniques have been studied, but the accuracy is not well known. Therefore, we performed a systematic meta-analysis to assess the diagnostic accuracy of anatomical and advanced MRI for treatment response in high-grade gliomas. Databases were searched systematically. Study selection and data extraction were done by two authors independently. Meta-analysis was performed using a bivariate random effects model when ≥5 studies were included. Anatomical MRI (five studies, 166 patients) showed a pooled sensitivity and specificity of 68% (95%CI 51-81) and 77% (45-93), respectively. Pooled apparent diffusion coefficients (seven studies, 204 patients) demonstrated a sensitivity of 71% (60-80) and specificity of 87% (77-93). DSC-perfusion (18 studies, 708 patients) sensitivity was 87% (82-91) with a specificity of 86% (77-91). DCE-perfusion (five studies, 207 patients) sensitivity was 92% (73-98) and specificity was 85% (76-92). The sensitivity of spectroscopy (nine studies, 203 patients) was 91% (79-97) and specificity was 95% (65-99). Advanced techniques showed higher diagnostic accuracy than anatomical MRI, the highest for spectroscopy, supporting the use in treatment response assessment in high-grade gliomas. (orig.)

  3. High diagnostic accuracy of the Sysmex XT-2000iV delta total nucleated cells on effusions for feline infectious peritonitis.

    Science.gov (United States)

    Giordano, Alessia; Stranieri, Angelica; Rossi, Gabriele; Paltrinieri, Saverio

    2015-06-01

    The ΔWBC (the ratio between DIFF and BASO counts of the Sysmex XT-2000iV), hereafter defined as ΔTNC (total nucleated cells), is high in effusions due to feline infectious peritonitis (FIP), as cells are entrapped in fibrin clots formed in the BASO reagent. Similar clots form in the Rivalta's test, a method with high diagnostic accuracy for FIP. The objective of this study was to determine the diagnostic accuracy for FIP and the optimal cutoff of ΔTNC. After a retrospective search of our database, DIFF and BASO counts, and the ΔTNC from cats with and without FIP were compared to each other. Sensitivity, specificity, and positive and negative likelihood ratios (LR+, LR-) were calculated. A ROC curve was designed to determine the cutoff for best sensitivity and specificity. Effusions from 20 FIP and 31 non-FIP cats were analyzed. The ΔTNC was higher (P  2.5 had 100% specificity. The ΔTNC has a high diagnostic accuracy for FIP-related effusions by providing an estimate of precipitable proteins, as the Rivalta's test, in addition to the cell count. As fibrin clots result in false lower BASO counts, the ΔTNC is preferable to the WBC count generated by the BASO channel alone in suspected FIP effusions. © 2015 American Society for Veterinary Clinical Pathology.

  4. Ground based interferometric radar initial look at Longview, Blue Springs, Tuttle Creek, and Milford Dams

    Science.gov (United States)

    Deng, Huazeng

    Measuring millimeter and smaller deformation has been demonstrated in the literature using RADAR. To address in part the limitations in current commercial satellite-based SAR datasets, a University of Missouri (MU) team worked with GAMMA Remote Sensing to develop a specialized (dual-frequency, polarimetric, and interferometric) ground-based real-aperture RADAR (GBIR) instrument. The GBIR device is portable with its tripod system and control electronics. It can be deployed to obtain data with high spatial resolution (i.e. on the order of 1 meter) and high temporal resolution (i.e. on the order 1 minute). The high temporal resolution is well suited for measurements of rapid deformation. From the same geodetic position, the GBIR may collect dual frequency data set using C-band and Ku-band. The overall goal of this project is to measure the deformation from various scenarios by applying the GBIR system. Initial efforts have been focusing on testing the system performance on different types of targets. This thesis details a number of my efforts on experimental and processing activities at the start of the MU GBIR imaging project. For improved close range capability, a wideband dual polarized antenna option was produced and tested. For GBIR calibration, several trihedral corner reflectors were designed and fabricated. In addition to experimental activities and site selection, I participated in advanced data processing activities. I processed GBIR data in several ways including single-look-complex (SLC) image generation, imagery registration, and interferometric processing. A number of initial-processed GBIR image products are presented from four dams: Longview, Blue Springs, Tuttle Creek, and Milford. Excellent imaging performance of the MU GBIR has been observed for various target types such as riprap, concrete, soil, rock, metal, and vegetation. Strong coherence of the test scene has been observed in the initial interferograms.

  5. Computational adaptive optics for broadband optical interferometric tomography of biological tissue.

    Science.gov (United States)

    Adie, Steven G; Graf, Benedikt W; Ahmad, Adeel; Carney, P Scott; Boppart, Stephen A

    2012-05-08

    Aberrations in optical microscopy reduce image resolution and contrast, and can limit imaging depth when focusing into biological samples. Static correction of aberrations may be achieved through appropriate lens design, but this approach does not offer the flexibility of simultaneously correcting aberrations for all imaging depths, nor the adaptability to correct for sample-specific aberrations for high-quality tomographic optical imaging. Incorporation of adaptive optics (AO) methods have demonstrated considerable improvement in optical image contrast and resolution in noninterferometric microscopy techniques, as well as in optical coherence tomography. Here we present a method to correct aberrations in a tomogram rather than the beam of a broadband optical interferometry system. Based on Fourier optics principles, we correct aberrations of a virtual pupil using Zernike polynomials. When used in conjunction with the computed imaging method interferometric synthetic aperture microscopy, this computational AO enables object reconstruction (within the single scattering limit) with ideal focal-plane resolution at all depths. Tomographic reconstructions of tissue phantoms containing subresolution titanium-dioxide particles and of ex vivo rat lung tissue demonstrate aberration correction in datasets acquired with a highly astigmatic illumination beam. These results also demonstrate that imaging with an aberrated astigmatic beam provides the advantage of a more uniform depth-dependent signal compared to imaging with a standard gaussian beam. With further work, computational AO could enable the replacement of complicated and expensive optical hardware components with algorithms implemented on a standard desktop computer, making high-resolution 3D interferometric tomography accessible to a wider group of users and nonspecialists.

  6. A New Image Processing Procedure Integrating PCI-RPC and ArcGIS-Spline Tools to Improve the Orthorectification Accuracy of High-Resolution Satellite Imagery

    Directory of Open Access Journals (Sweden)

    Hongying Zhang

    2016-10-01

    Full Text Available Given the low accuracy of the traditional remote sensing image processing software when orthorectifying satellite images that cover mountainous areas, and in order to make a full use of mutually compatible and complementary characteristics of the remote sensing image processing software PCI-RPC (Rational Polynomial Coefficients and ArcGIS-Spline, this study puts forward a new operational and effective image processing procedure to improve the accuracy of image orthorectification. The new procedure first processes raw image data into an orthorectified image using PCI with RPC model (PCI-RPC, and then the orthorectified image is further processed using ArcGIS with the Spline tool (ArcGIS-Spline. We used the high-resolution CBERS-02C satellite images (HR1 and HR2 scenes with a pixel size of 2 m acquired from Yangyuan County in Hebei Province of China to test the procedure. In this study, when separately using PCI-RPC and ArcGIS-Spline tools directly to process the HR1/HR2 raw images, the orthorectification accuracies (root mean square errors, RMSEs for HR1/HR2 images were 2.94 m/2.81 m and 4.65 m/4.41 m, respectively. However, when using our newly proposed procedure, the corresponding RMSEs could be reduced to 1.10 m/1.07 m. The experimental results demonstrated that the new image processing procedure which integrates PCI-RPC and ArcGIS-Spline tools could significantly improve image orthorectification accuracy. Therefore, in terms of practice, the new procedure has the potential to use existing software products to easily improve image orthorectification accuracy.

  7. Three-step interferometric method with blind phase shifts by use of interframe correlation between interferograms

    Science.gov (United States)

    Muravsky, Leonid I.; Kmet', Arkady B.; Stasyshyn, Ihor V.; Voronyak, Taras I.; Bobitski, Yaroslav V.

    2018-06-01

    A new three-step interferometric method with blind phase shifts to retrieve phase maps (PMs) of smooth and low-roughness engineering surfaces is proposed. Evaluating of two unknown phase shifts is fulfilled by using the interframe correlation between interferograms. The method consists of two stages. The first stage provides recording of three interferograms of a test object and their processing including calculation of unknown phase shifts, and retrieval of a coarse PM. The second stage implements firstly separation of high-frequency and low-frequency PMs and secondly producing of a fine PM consisting of areal surface roughness and waviness PMs. Extraction of the areal surface roughness and waviness PMs is fulfilled by using a linear low-pass filter. The computer simulation and experiments fulfilled to retrieve a gauge block surface area and its areal surface roughness and waviness have confirmed the reliability of the proposed three-step method.

  8. Broadband interferometric characterisation of nano-positioning stages with sub-10 pm resolution

    Science.gov (United States)

    Li, Zhi; Brand, Uwe; Wolff, Helmut; Koenders, Ludger; Yacoot, Andrew; Puranto, Prabowo

    2017-06-01

    A traceable calibration setup for investigation of the quasi-static and the dynamic performance of nano-positioning stages is detailed, which utilizes a differential plane-mirror interferometer with double-pass configuration from the National Physical Laboratory (NPL). An NPL-developed FPGA-based interferometric data acquisition and decoding system has been used to enable traceable quasi-static calibration of nano-positioning stages with high resolution. A lockin based modulation technique is further introduced to quantitatively calibrate the dynamic response of moving stages with a bandwidth up to 100 kHz and picometer resolution. First experimental results have proven that the calibration setup can achieve under nearly open-air conditions a noise floor lower than 10 pm/sqrt(Hz). A pico-positioning stage, that is used for nanoindentation with indentation depths down to a few picometers, has been characterized with this calibration setup.

  9. Mach-Zehnder interferometric photonic crystal fiber for low acoustic frequency detections

    Energy Technology Data Exchange (ETDEWEB)

    Pawar, Dnyandeo; Rao, Ch. N.; Kale, S. N., E-mail: sangeetakale2004@gmail.com [Department of Applied Physics, Defence Institute of Advanced Technology (DU), Girinagar, Pune 411 025, Maharashtra (India); Choubey, Ravi Kant [Department of Applied Physics, Amity Institute of Applied Sciences, Amity University, Noida 201 313 (India)

    2016-01-25

    Low frequency under-water acoustic signal detections are challenging, especially for marine applications. A Mach-Zehnder interferometric hydrophone is demonstrated using polarization-maintaining photonic-crystal-fiber (PM-PCF), spliced between two single-mode-fibers, operated at 1550 nm source. These data are compared with standard hydrophone, single-mode and multimode fiber. The PM-PCF sensor shows the highest response with a power shift (2.32 dBm) and a wavelength shift (392.8 pm) at 200 Hz. High birefringence values and the effect of the imparted acoustic pressure on this fiber, introducing the difference between the fast and slow axis changes, owing to the phase change in the propagation waves, demonstrate the strain-optic properties of the sensor.

  10. Manipulations of Wavefront Propagation: Useful Methods and Applications for Interferometric Measurements and Scanning

    Directory of Open Access Journals (Sweden)

    Avi Karsenty

    2017-01-01

    Full Text Available Phase measurements obtained by high-coherence interferometry are restricted by the 2π ambiguity, to height differences smaller than λ/2. A further restriction in most interferometric systems is for focusing the system on the measured object. We present two methods that overcome these restrictions. In the first method, different segments of a measured wavefront are digitally propagated and focused locally after measurement. The divergent distances, by which the diverse segments of the wavefront are propagated in order to achieve a focused image, provide enough information so as to resolve the 2π ambiguity. The second method employs an interferogram obtained by a spectrum constituting a small number of wavelengths. The magnitude of the interferogram’s modulations is utilized to resolve the 2π ambiguity. Such methods of wavefront propagation enable several applications such as focusing and resolving the 2π ambiguity, as described in the article.

  11. Ortho-Babinet polarization-interrogating filter: an interferometric approach to polarization measurement.

    Science.gov (United States)

    Van Delden, Jay S

    2003-07-15

    A novel, interferometric, polarization-interrogating filter assembly and method for the simultaneous measurement of all four Stokes parameters across a partially polarized irradiance image in a no-moving-parts, instantaneous, highly sensitive manner is described. In the reported embodiment of the filter, two spatially varying linear retarders and a linear polarizer comprise an ortho-Babinet, polarization-interrogating (OBPI) filter. The OBPI filter uniquely encodes the incident ensemble of electromagnetic wave fronts comprising a partially polarized irradiance image in a controlled, deterministic, spatially varying manner to map the complete state of polarization across the image to local variations in a superposed interference pattern. Experimental interferograms are reported along with a numerical simulation of the method.

  12. Improved imputation accuracy of rare and low-frequency variants using population-specific high-coverage WGS-based imputation reference panel.

    Science.gov (United States)

    Mitt, Mario; Kals, Mart; Pärn, Kalle; Gabriel, Stacey B; Lander, Eric S; Palotie, Aarno; Ripatti, Samuli; Morris, Andrew P; Metspalu, Andres; Esko, Tõnu; Mägi, Reedik; Palta, Priit

    2017-06-01

    Genetic imputation is a cost-efficient way to improve the power and resolution of genome-wide association (GWA) studies. Current publicly accessible imputation reference panels accurately predict genotypes for common variants with minor allele frequency (MAF)≥5% and low-frequency variants (0.5≤MAF<5%) across diverse populations, but the imputation of rare variation (MAF<0.5%) is still rather limited. In the current study, we evaluate imputation accuracy achieved with reference panels from diverse populations with a population-specific high-coverage (30 ×) whole-genome sequencing (WGS) based reference panel, comprising of 2244 Estonian individuals (0.25% of adult Estonians). Although the Estonian-specific panel contains fewer haplotypes and variants, the imputation confidence and accuracy of imputed low-frequency and rare variants was significantly higher. The results indicate the utility of population-specific reference panels for human genetic studies.

  13. Characterization of ANFO explosive by high accuracy ESI(±)-FTMS with forensic identification on real samples by EASI(-)-MS.

    Science.gov (United States)

    Hernandes, Vinicius Veri; Franco, Marcos Fernado; Santos, Jandyson Machado; Melendez-Perez, Jose J; de Morais, Damila Rodrigues; Rocha, Werickson Fortunato de Carvalho; Borges, Rodrigo; de Souza, Wanderley; Zacca, Jorge Jardim; Logrado, Lucio Paulo Lima; Eberlin, Marcos Nogueira; Correa, Deleon Nascimento

    2015-04-01

    Ammonium nitrate fuel oil (ANFO) is an explosive used in many civil applications. In Brazil, ANFO has unfortunately also been used in criminal attacks, mainly in automated teller machine (ATM) explosions. In this paper, we describe a detailed characterization of the ANFO composition and its two main constituents (diesel and a nitrate explosive) using high resolution and accuracy mass spectrometry performed on an FT-ICR-mass spectrometer with electrospray ionization (ESI(±)-FTMS) in both the positive and negative ion modes. Via ESI(-)-MS, an ion marker for ANFO was characterized. Using a direct and simple ambient desorption/ionization technique, i.e., easy ambient sonic-spray ionization mass spectrometry (EASI-MS), in a simpler, lower accuracy but robust single quadrupole mass spectrometer, the ANFO ion marker was directly detected from the surface of banknotes collected from ATM explosion theft. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  14. High-accuracy diagnostic tool for electron cloud observation in the LHC based on synchronous phase measurements

    CERN Document Server

    Esteban Müller, J F; Shaposhnikova, E; Valuch, D; Mastoridis, T

    2014-01-01

    Electron cloud effects such as heat load in the cryogenic system, pressure rise and beam instabilities are among the main limitations for the LHC operation with 25 ns spaced bunches. A new observation tool was developed to monitor the e-cloud activity and has been successfully used in the LHC during Run 1 (2010-2012). The power loss of each bunch due to the e-cloud can be estimated using very precise bunch-by-bunch measurement of the synchronous phase shift. In order to achieve the required accuracy, corrections for reflection in the cables and some systematic errors need to be applied followed by a post-processing of the measurements. Results clearly show the e-cloud build-up along the bunch trains and its evolution during each LHC fill as well as from fill to fill. Measurements during the 2012 LHC scrubbing run reveal a progressive reduction in the e-cloud activity and therefore a decrease in the secondary electron yield (SEY). The total beam power loss can be computed as a sum of the contributions from all...

  15. High-accuracy phase-field models for brittle fracture based on a new family of degradation functions

    Science.gov (United States)

    Sargado, Juan Michael; Keilegavlen, Eirik; Berre, Inga; Nordbotten, Jan Martin

    2018-02-01

    Phase-field approaches to fracture based on energy minimization principles have been rapidly gaining popularity in recent years, and are particularly well-suited for simulating crack initiation and growth in complex fracture networks. In the phase-field framework, the surface energy associated with crack formation is calculated by evaluating a functional defined in terms of a scalar order parameter and its gradients. These in turn describe the fractures in a diffuse sense following a prescribed regularization length scale. Imposing stationarity of the total energy leads to a coupled system of partial differential equations that enforce stress equilibrium and govern phase-field evolution. These equations are coupled through an energy degradation function that models the loss of stiffness in the bulk material as it undergoes damage. In the present work, we introduce a new parametric family of degradation functions aimed at increasing the accuracy of phase-field models in predicting critical loads associated with crack nucleation as well as the propagation of existing fractures. An additional goal is the preservation of linear elastic response in the bulk material prior to fracture. Through the analysis of several numerical examples, we demonstrate the superiority of the proposed family of functions to the classical quadratic degradation function that is used most often in the literature.

  16. High accuracy navigation information estimation for inertial system using the multi-model EKF fusing adams explicit formula applied to underwater gliders.

    Science.gov (United States)

    Huang, Haoqian; Chen, Xiyuan; Zhang, Bo; Wang, Jian

    2017-01-01

    The underwater navigation system, mainly consisting of MEMS inertial sensors, is a key technology for the wide application of underwater gliders and plays an important role in achieving high accuracy navigation and positioning for a long time of period. However, the navigation errors will accumulate over time because of the inherent errors of inertial sensors, especially for MEMS grade IMU (Inertial Measurement Unit) generally used in gliders. The dead reckoning module is added to compensate the errors. In the complicated underwater environment, the performance of MEMS sensors is degraded sharply and the errors will become much larger. It is difficult to establish the accurate and fixed error model for the inertial sensor. Therefore, it is very hard to improve the accuracy of navigation information calculated by sensors. In order to solve the problem mentioned, the more suitable filter which integrates the multi-model method with an EKF approach can be designed according to different error models to give the optimal estimation for the state. The key parameters of error models can be used to determine the corresponding filter. The Adams explicit formula which has an advantage of high precision prediction is simultaneously fused into the above filter to achieve the much more improvement in attitudes estimation accuracy. The proposed algorithm has been proved through theory analyses and has been tested by both vehicle experiments and lake trials. Results show that the proposed method has better accuracy and effectiveness in terms of attitudes estimation compared with other methods mentioned in the paper for inertial navigation applied to underwater gliders. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  17. Pulse retrieval algorithm for interferometric frequency-resolved optical gating based on differential evolution.

    Science.gov (United States)

    Hyyti, Janne; Escoto, Esmerando; Steinmeyer, Günter

    2017-10-01

    A novel algorithm for the ultrashort laser pulse characterization method of interferometric frequency-resolved optical gating (iFROG) is presented. Based on a genetic method, namely, differential evolution, the algorithm can exploit all available information of an iFROG measurement to retrieve the complex electric field of a pulse. The retrieval is subjected to a series of numerical tests to prove the robustness of the algorithm against experimental artifacts and noise. These tests show that the integrated error-correction mechanisms of the iFROG method can be successfully used to remove the effect from timing errors and spectrally varying efficiency in the detection. Moreover, the accuracy and noise resilience of the new algorithm are shown to outperform retrieval based on the generalized projections algorithm, which is widely used as the standard method in FROG retrieval. The differential evolution algorithm is further validated with experimental data, measured with unamplified three-cycle pulses from a mode-locked Ti:sapphire laser. Additionally introducing group delay dispersion in the beam path, the retrieval results show excellent agreement with independent measurements with a commercial pulse measurement device based on spectral phase interferometry for direct electric-field retrieval. Further experimental tests with strongly attenuated pulses indicate resilience of differential-evolution-based retrieval against massive measurement noise.

  18. Coherent change detection and interferometric ISAR measurements in the folded compact range

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, K.W.

    1996-08-01

    A folded compact range configuration has been developed ant the Sandia National Laboratories` compact range antenna and radar-cross- section measurement facility as a means of performing indoor, environmentally-controlled, far-field simulations of synthetic aperture radar (SAR) measurements of distributed target samples (i.e. gravel, sand, etc.). The folded compact range configuration has previously been used to perform coherent-change-detection (CCD) measurements, which allow disturbances to distributed targets on the order of fractions of a wavelength to be detected. This report describes follow-on CCD measurements of other distributed target samples, and also investigates the sensitivity of the CCD measurement process to changes in the relative spatial location of the SAR sensor between observations of the target. Additionally, this report describes the theoretical and practical aspects of performing interferometric inverse-synthetic-aperture-radar (IFISAR) measurements in the folded compact range environment. IFISAR measurements provide resolution of the relative heights of targets with accuracies on the order of a wavelength. Several examples are given of digital height maps that have been generated from measurements performed at the folded compact range facility.

  19. Interferometric 30 m bench for calibrations of 1D scales and optical distance measuring instruments

    International Nuclear Information System (INIS)

    Unkuri, J; Rantanen, A; Manninen, J; Esala, V-P; Lassila, A

    2012-01-01

    During construction of a new metrology building for MIKES, a 30 m interferometric bench was designed. The objective was to implement a straight, stable, adjustable and multifunctional 30 m measuring bench for calibrations. Special attention was paid to eliminating the effects of thermal expansion and inevitable concrete shrinkage. The linear guide, situated on top of a monolithic concrete beam, comprises two parallel round shafts with adjustable fixtures every 1 m. A carriage is moved along the rail and its position is followed by a reference interferometer. Depending on the measurement task, one or two retro-reflectors are fixed on the carriage. A microscope with a CCD camera and a monitor can be used to detect line mark positions on different line standards. When calibrating optical distance measuring instruments, various targets can be fixed to the carriage. For the most accurate measurements an online Abbe-error correction based on simultaneous carriage pitch measurement by a separate laser interferometer is applied. The bench is used for calibrations of machinist scales, tapes, circometers, electronic distance meters, total stations and laser trackers. The estimated expanded uncertainty for 30 m displacement for highest accuracy calibrations is 2.6 µm. (paper)

  20. Meditation experience predicts introspective accuracy.

    Directory of Open Access Journals (Sweden)

    Kieran C R Fox

    Full Text Available The accuracy of subjective reports, especially those involving introspection of one's own internal processes, remains unclear, and research has demonstrated large individual differences in introspective accuracy. It has been hypothesized that introspective accuracy may be heightened in persons who engage in meditation practices, due to the highly introspective nature of such practices. We undertook a preliminary exploration of this hypothesis, examining introspective accuracy in a cross-section of meditation practitioners (1-15,000 hrs experience. Introspective accuracy was assessed by comparing subjective reports of tactile sensitivity for each of 20 body regions during a 'body-scanning' meditation with averaged, objective measures of tactile sensitivity (mean size of body representation area in primary somatosensory cortex; two-point discrimination threshold as reported in prior research. Expert meditators showed significantly better introspective accuracy than novices; overall meditation experience also significantly predicted individual introspective accuracy. These results suggest that long-term meditators provide more accurate introspective reports than novices.

  1. Measurement of high-energy (10–60 keV) x-ray spectral line widths with eV accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Seely, J. F., E-mail: seelyjf@gmail.com; Feldman, U. [Artep Inc., 2922 Excelsior Springs Court, Ellicott City, Maryland 21042 (United States); Glover, J. L.; Hudson, L. T.; Ralchenko, Y.; Henins, Albert [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Pereira, N. [Ecopulse Inc., P. O. Box 528, Springfield, Virginia 22152 (United States); Di Stefano, C. A.; Kuranz, C. C.; Drake, R. P. [University of Michigan, Ann Arbor, Michigan 48109 (United States); Chen, Hui; Williams, G. J.; Park, J. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

    2014-11-15

    A high resolution crystal spectrometer utilizing a crystal in transmission geometry has been developed and experimentally optimized to measure the widths of emission lines in the 10–60 keV energy range with eV accuracy. The spectrometer achieves high spectral resolution by utilizing crystal planes with small lattice spacings (down to 2d = 0.099 nm), a large crystal bending radius and Rowland circle diameter (965 mm), and an image plate detector with high spatial resolution (60 μm in the case of the Fuji TR image plate). High resolution W L-shell and K-shell laboratory test spectra in the 10–60 keV range and Ho K-shell spectra near 47 keV recorded at the LLNL Titan laser facility are presented. The Ho K-shell spectra are the highest resolution hard x-ray spectra recorded from a solid target irradiated by a high-intensity laser.

  2. High diagnostic accuracy of low-dose gated-SPECT with solid-state ultrafast detectors: preliminary clinical results

    Energy Technology Data Exchange (ETDEWEB)

    Gimelli, Alessia; Genovesi, Dario; Giorgetti, Assuero; Marzullo, Paolo [CNR, Fondazione Toscana Gabriele Monasterio, Pisa (Italy); Bottai, Matteo [University of South Carolina, Division of Biostatistics, Columbia, SC (United States); Karolinska Institutet, Division of Biostatistics, Stockholm (Sweden); Di Martino, Fabio [AOUP, UO Fisica Sanitaria, Pisa (Italy)

    2012-01-15

    Appropriate use of SPECT imaging is regulated by evidence-based guidelines and appropriateness criteria in an effort to limit the burden of radiation administered to patients. We aimed at establishing whether the use of a low dose for stress-rest single-day nuclear myocardial perfusion imaging on an ultrafast (UF) cardiac gamma camera using cadmium-zinc-telluride solid-state detectors could be used routinely with the same accuracy obtained with standard doses and conventional cameras. To this purpose, 137 consecutive patients (mean age 61 {+-} 8 years) with known or suspected coronary artery disease (CAD) were enrolled. They underwent single-day low-dose stress-rest myocardial perfusion imaging using UF SPECT and invasive coronary angiography. Patients underwent the first scan with a 7-min acquisition time 10 min after the end of the stress protocol (dose range 185 to 222 MBq of {sup 99m}Tc-tetrofosmin). The rest scan (dose range 370 to 444 MBq of {sup 99m}Tc-tetrofosmin) was acquired with a 6-min acquisition time. The mean summed stress scores (SSS) and mean summed rest scores (SRS) were obtained semiquantitatively. Coronary angiograms showed significant epicardial CAD in 83% of patients. Mean SSS and SRS were 10 {+-} 5 and 3 {+-} 3, respectively. Overall the area under the ROC curve for the SSS values was 0.904, while the areas under the ROC curves for each vascular territory were 0.982 for the left anterior descending artery, 0.931 for the left circumflex artery and 0.889 for the right coronary artery. This pilot study demonstrated the feasibility of a low-dose single-day stress-rest fasting protocol performed using UF SPECT, with good sensitivity and specificity in detecting CAD at low patient exposure, opening new perspectives in the use of myocardial perfusion in ischaemic patients. (orig.)

  3. High diagnostic accuracy of low-dose gated-SPECT with solid-state ultrafast detectors: preliminary clinical results

    International Nuclear Information System (INIS)

    Gimelli, Alessia; Genovesi, Dario; Giorgetti, Assuero; Marzullo, Paolo; Bottai, Matteo; Di Martino, Fabio

    2012-01-01

    Appropriate use of SPECT imaging is regulated by evidence-based guidelines and appropriateness criteria in an effort to limit the burden of radiation administered to patients. We aimed at establishing whether the use of a low dose for stress-rest single-day nuclear myocardial perfusion imaging on an ultrafast (UF) cardiac gamma camera using cadmium-zinc-telluride solid-state detectors could be used routinely with the same accuracy obtained with standard doses and conventional cameras. To this purpose, 137 consecutive patients (mean age 61 ± 8 years) with known or suspected coronary artery disease (CAD) were enrolled. They underwent single-day low-dose stress-rest myocardial perfusion imaging using UF SPECT and invasive coronary angiography. Patients underwent the first scan with a 7-min acquisition time 10 min after the end of the stress protocol (dose range 185 to 222 MBq of 99m Tc-tetrofosmin). The rest scan (dose range 370 to 444 MBq of 99m Tc-tetrofosmin) was acquired with a 6-min acquisition time. The mean summed stress scores (SSS) and mean summed rest scores (SRS) were obtained semiquantitatively. Coronary angiograms showed significant epicardial CAD in 83% of patients. Mean SSS and SRS were 10 ± 5 and 3 ± 3, respectively. Overall the area under the ROC curve for the SSS values was 0.904, while the areas under the ROC curves for each vascular territory were 0.982 for the left anterior descending artery, 0.931 for the left circumflex artery and 0.889 for the right coronary artery. This pilot study demonstrated the feasibility of a low-dose single-day stress-rest fasting protocol performed using UF SPECT, with good sensitivity and specificity in detecting CAD at low patient exposure, opening new perspectives in the use of myocardial perfusion in ischaemic patients. (orig.)

  4. Real-time continuous glucose monitoring shows high accuracy within 6 hours after sensor calibration: a prospective study.

    Directory of Open Access Journals (Sweden)

    Xiao-Yan Yue

    Full Text Available Accurate and timely glucose monitoring is essential in intensive care units. Real-time continuous glucose monitoring system (CGMS has been advocated for many years to improve glycemic management in critically ill patients. In order to determine the effect of calibration time on the accuracy of CGMS, real-time subcutaneous CGMS was used in 18 critically ill patients. CGMS sensor was calibrated with blood glucose measurements by blood gas/glucose analyzer every 12 hours. Venous blood was sampled every 2 to 4 hours, and glucose concentration was measured by standard central laboratory device (CLD and by blood gas/glucose analyzer. With CLD measurement as reference, relative absolute difference (mean±SD in CGMS and blood gas/glucose analyzer were 14.4%±12.2% and 6.5%±6.2%, respectively. The percentage of matched points in Clarke error grid zone A was 74.8% in CGMS, and 98.4% in blood gas/glucose analyzer. The relative absolute difference of CGMS obtained within 6 hours after sensor calibration (8.8%±7.2% was significantly less than that between 6 to 12 hours after calibration (20.1%±13.5%, p<0.0001. The percentage of matched points in Clarke error grid zone A was also significantly higher in data sets within 6 hours after calibration (92.4% versus 57.1%, p<0.0001. In conclusion, real-time subcutaneous CGMS is accurate in glucose monitoring in critically ill patients. CGMS sensor should be calibrated less than 6 hours, no matter what time interval recommended by manufacturer.

  5. Interferometric data modelling: issues in realistic data generation

    International Nuclear Information System (INIS)

    Mukherjee, Soma

    2004-01-01

    This study describes algorithms developed for modelling interferometric noise in a realistic manner, i.e. incorporating non-stationarity that can be seen in the data from the present generation of interferometers. The noise model is based on individual component models (ICM) with the application of auto regressive moving average (ARMA) models. The data obtained from the model are vindicated by standard statistical tests, e.g. the KS test and Akaike minimum criterion. The results indicate a very good fit. The advantage of using ARMA for ICMs is that the model parameters can be controlled and hence injection and efficiency studies can be conducted in a more controlled environment. This realistic non-stationary noise generator is intended to be integrated within the data monitoring tool framework

  6. Interferometric control of the photon-number distribution

    Directory of Open Access Journals (Sweden)

    H. Esat Kondakci

    2017-07-01

    Full Text Available We demonstrate deterministic control over the photon-number distribution by interfering two coherent beams within a disordered photonic lattice. By sweeping a relative phase between two equal-amplitude coherent fields with Poissonian statistics that excite adjacent sites in a lattice endowed with disorder-immune chiral symmetry, we measure an output photon-number distribution that changes periodically between super-thermal and sub-thermal photon statistics upon ensemble averaging. Thus, the photon-bunching level is controlled interferometrically at a fixed mean photon-number by gradually activating the excitation symmetry of the chiral-mode pairs with structured coherent illumination and without modifying the disorder level of the random system itself.

  7. INTERFEROMETRIC SYNTHETIC APERTURE RADAR (INSAR TECHNOLOGY AND GEOMORPHOLOGY INTERPRETATION

    Directory of Open Access Journals (Sweden)

    M. Maghsoudi

    2013-09-01

    Full Text Available Geomorphology is briefly the study of landforms and their formative processes on the surface of the planet earth as human habitat. The landforms evolution and the formative processes can best be studied by technologies with main application in study of elevation. Interferometric Synthetic Aperture Radar (InSAR is the appropriate technology for this application. With phase differences calculations in radar waves, the results of this technology can extensively be interpreted for geomorphologic researches. The purpose of the study is to review the geomorphologic studies using InSAR and also the technical studies about InSAR with geomorphologic interpretations. This study states that the InSAR technology can be recommended to be employed as a fundamental for geomorphology researches.

  8. Segmented Aperture Interferometric Nulling Testbed (SAINT) II: component systems update

    Science.gov (United States)

    Hicks, Brian A.; Bolcar, Matthew R.; Helmbrecht, Michael A.; Petrone, Peter; Burke, Elliot; Corsetti, James; Dillon, Thomas; Lea, Andrew; Pellicori, Samuel; Sheets, Teresa; Shiri, Ron; Agolli, Jack; DeVries, John; Eberhardt, Andrew; McCabe, Tyler

    2017-09-01

    This work presents updates to the coronagraph and telescope components of the Segmented Aperture Interferometric Nulling Testbed (SAINT). The project pairs an actively-controlled macro-scale segmented mirror with the Visible Nulling Coronagraph (VNC) towards demonstrating capabilities for the future space observatories needed to directly detect and characterize a significant sample of Earth-sized worlds around nearby stars in the quest for identifying those which may be habitable and possibly harbor life. Efforts to improve the VNC wavefront control optics and mechanisms towards repeating narrowband results are described. A narrative is provided for the design of new optical components aimed at enabling broadband performance. Initial work with the hardware and software interface for controlling the segmented telescope mirror is also presented.

  9. All-optical phase modulation for integrated interferometric biosensors.

    Science.gov (United States)

    Dante, Stefania; Duval, Daphné; Sepúlveda, Borja; González-Guerrero, Ana Belen; Sendra, José Ramón; Lechuga, Laura M

    2012-03-26

    We present the theoretical and the experimental implementation of an all-optical phase modulation system in integrated Mach-Zehnder Interferometers to solve the drawbacks related to the periodic nature of the interferometric signal. Sensor phase is tuned by modulating the emission wavelength of low-cost commercial laser diodes by changing their output power. FFT deconvolution of the signal allows for direct phase readout, immune to sensitivity variations and to light intensity fluctuations. This simple phase modulation scheme increases the signal-to-noise ratio of the measurements in one order of magnitude, rendering in a sensor with a detection limit of 1.9·10⁻⁷ RIU. The viability of the all-optical modulation approach is demonstrated with an immunoassay detection as a biosensing proof of concept.

  10. Advanced Virgo: a second-generation interferometric gravitational wave detector

    International Nuclear Information System (INIS)

    Acernese, F; Barone, F; Agathos, M; Agatsuma, K; Bauer, Th S; Beker, M G; Aisa, D; Allemandou, N; Allocca, A; Amarni, J; Baronick, J-P; Barsuglia, M; Astone, P; Basti, F; Balestri, G; Ballardin, G; Bavigadda, V; Basti, A; Bejger, M; Belczynski, C

    2015-01-01

    Advanced Virgo is the project to upgrade the Virgo interferometric detector of gravitational waves, with the aim of increasing the number of observable galaxies (and thus the detection rate) by three orders of magnitude. The project is now in an advanced construction phase and the assembly and integration will be completed by the end of 2015. Advanced Virgo will be part of a network, alongside the two Advanced LIGO detectors in the US and GEO HF in Germany, with the goal of contributing to the early detection of gravitational waves and to opening a new window of observation on the universe. In this paper we describe the main features of the Advanced Virgo detector and outline the status of the construction. (paper)

  11. Interferometric detectors of gravitational waves on Earth: the next generations

    Energy Technology Data Exchange (ETDEWEB)

    Losurdo, G [INFN Firenze - Via G.Sansone 1, 50019 - Sesto F., Firenze (Italy)], E-mail: losurdo@fi.infn.it

    2008-05-15

    First generation long-baseline interferometric detectors of gravitational waves are now taking data. A first detection might be possible with these instruments, but more sensitive detectors will be needed to start the field of gravitational wave astronomy. Second generation interferometers will improve the sensitivity by a factor ten, allowing to explore a universe volume 1000 times larger. The technology is almost ready and the construction will start at the beginning of the next decade. The community of the physicists involved in the field has also started to make plans for third generation detectors, for which a long term technology development program will be required. The plans for the upgrades of the existing detectors and the scenario for the evolution of the field will be reviewed in this paper.

  12. Parametric estimation of time varying baselines in airborne interferometric SAR

    DEFF Research Database (Denmark)

    Mohr, Johan Jacob; Madsen, Søren Nørvang

    1996-01-01

    A method for estimation of time varying spatial baselines in airborne interferometric synthetic aperture radar (SAR) is described. The range and azimuth distortions between two images acquired with a non-linear baseline are derived. A parametric model of the baseline is then, in a least square...... sense, estimated from image shifts obtained by cross correlation of numerous small patches throughout the image. The method has been applied to airborne EMISAR imagery from the 1995 campaign over the Storstrommen Glacier in North East Greenland conducted by the Danish Center for Remote Sensing. This has...... reduced the baseline uncertainties from several meters to the centimeter level in a 36 km scene. Though developed for airborne SAR the method can easily be adopted to satellite data...

  13. Enhancing Raman signals with an interferometrically controlled AFM tip

    International Nuclear Information System (INIS)

    Oron-Carl, Matti; Krupke, Ralph

    2013-01-01

    We demonstrate the upgrade of a commercial confocal Raman microscope into a tip-enhanced Raman microscope/spectroscopy system (TERS) by integrating an interferometrically controlled atomic force microscope into the base of an existing upright microscope to provide near-field detection and thus signal enhancement. The feasibility of the system is demonstrated by measuring the Raman near-field enhancement on thin PEDOT:PSS films and on carbon nanotubes within a device geometry. An enhancement factor of 2–3 and of 5–6 is observed, respectively. Moreover, on a nanotube device we show local conductivity measurement and its correlation to Raman and topography recordings. Upgrading an existing upright confocal Raman microscope in the demonstrated way is significantly cheaper than purchasing a complete commercial TERS system. (paper)

  14. Heterodyne interferometric technique for displacement control at the nanometric scale

    Science.gov (United States)

    Topcu, Suat; Chassagne, Luc; Haddad, Darine; Alayli, Yasser; Juncar, Patrick

    2003-11-01

    We propose a method of displacement control that addresses the measurement requirements of the nanotechnology community and provide a traceability to the definition of the mèter at the nanometric scale. The method is based on the use of both a heterodyne Michelson's interferometer and a homemade high frequency electronic circuit. The system so established allows us to control the displacement of a translation stage with a known step of 4.945 nm. Intrinsic relative uncertainty on the step value is 1.6×10-9. Controls of the period of repetition of these steps with a high-stability quartz oscillator permits to impose an uniform speed to the translation stage with the same accuracy. This property will be used for the watt balance project of the Bureau National de Métrologie of France.

  15. The accuracy of {sup 68}Ga-PSMA PET/CT in primary lymph node staging in high-risk prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Oebek, Can; Doganca, Tuenkut [Acibadem Taksim Hospital, Department of Urology, Istanbul (Turkey); Demirci, Emre [Sisli Etfal Training and Research Hospital, Department of Nuclear Medicine, Istanbul (Turkey); Ocak, Meltem [Istanbul University, Faculty of Pharmacy, Department of Pharmaceutical Technology, Istanbul (Turkey); Kural, Ali Riza [Acibadem University, Department of Urology, Istanbul (Turkey); Yildirim, Asif [Istanbul Medeniyet University, Department of Urology, Istanbul (Turkey); Yuecetas, Ugur [Istanbul Training and Research Hospital, Department of Urology, Istanbul (Turkey); Demirdag, Cetin [Istanbul University, Cerrahpasa School of Medicine, Department of Urology, Istanbul (Turkey); Erdogan, Sarper M. [Istanbul University, Cerrahpasa School of Medicine, Department of Public Health, Istanbul (Turkey); Kabasakal, Levent [Istanbul University, Cerrahpasa School of Medicine, Department of Nuclear Medicine, Istanbul (Turkey); Collaboration: Members of Urooncology Association, Turkey

    2017-10-15

    To assess the diagnostic accuracy of {sup 68}Ga-PSMA PET in predicting lymph node (LN) metastases in primary N staging in high-risk and very high-risk nonmetastatic prostate cancer in comparison with morphological imaging. This was a multicentre trial of the Society of Urologic Oncology in Turkey in conjunction with the Nuclear Medicine Department of Cerrahpasa School of Medicine, Istanbul University. Patients were accrued from eight centres. Patients with high-risk and very high-risk disease scheduled to undergo surgical treatment with extended LN dissection between July 2014 and October 2015 were included. Either MRI or CT was used for morphological imaging. PSMA PET/CT was performed and evaluated at a single centre. Sensitivity, specificity and accuracy were calculated for the detection of lymphatic metastases by PSMA PET/CT and morphological imaging. Kappa values were calculated to evaluate the correlation between the numbers of LN metastases detected by PSMA PET/CT and by histopathology. Data on 51 eligible patients are presented. The sensitivity, specificity and accuracy of PSMA PET in detecting LN metastases in the primary setting were 53%, 86% and 76%, and increased to 67%, 88% and 81% in the subgroup with of patients with ≥15 LN removed. Kappa values for the correlation between imaging and pathology were 0.41 for PSMA PET and 0.18 for morphological imaging. PSMA PET/CT is superior to morphological imaging for the detection of metastatic LNs in patients with primary prostate cancer. Surgical dissection remains the gold standard for precise lymphatic staging. (orig.)

  16. Improving waveform inversion using modified interferometric imaging condition

    Science.gov (United States)

    Guo, Xuebao; Liu, Hong; Shi, Ying; Wang, Weihong; Zhang, Zhen

    2018-02-01

    Similar to the reverse-time migration, full waveform inversion in the time domain is a memory-intensive processing method. The computational storage size for waveform inversion mainly depends on the model size and time recording length. In general, 3D and 4D data volumes need to be saved for 2D and 3D waveform inversion gradient calculations, respectively. Even the boundary region wavefield-saving strategy creates a huge storage demand. Using the last two slices of the wavefield to reconstruct wavefields at other moments through the random boundary, avoids the need to store a large number of wavefields; however, traditional random boundary method is less effective at low frequencies. In this study, we follow a new random boundary designed to regenerate random velocity anomalies in the boundary region for each shot of each iteration. The results obtained using the random boundary condition in less illuminated areas are more seriously affected by random scattering than other areas due to the lack of coverage. In this paper, we have replaced direct correlation for computing the waveform inversion gradient by modified interferometric imaging, which enhances the continuity of the imaging path and reduces noise interference. The new imaging condition is a weighted average of extended imaging gathers can be directly used in the gradient computation. In this process, we have not changed the objective function, and the role of the imaging condition is similar to regularization. The window size for the modified interferometric imaging condition-based waveform inversion plays an important role in this process. The numerical examples show that the proposed method significantly enhances waveform inversion performance.

  17. Evaluation of the accuracy of the CellaVision™ DM96 in a high HIV-prevalence population in South Africa

    Directory of Open Access Journals (Sweden)

    Jenifer L. Vaughan

    2016-03-01

    Objectives: This study aimed to evaluate the accuracy of the DM96 in a South African laboratory, with emphasis on its performance in samples collected from HIV-positive patients. Methods: A total of 149 samples submitted for a routine differential white cell count in 2012 and 2013 at the Chris Hani Baragwanath Academic Hospital in Johannesburg, South Africa were included, of which 79 (53.0% were collected from HIV-positive patients. Results of DM96 analysis pre- and post-classification were compared with a manual differential white cell count and the impact of HIV infection and other variables of interest were assessed. Results: Pre- and post-classification accuracies were similar to those reported in developed countries. Reclassification was required in 16% of cells, with particularly high misclassification rates for eosinophils (31.7%, blasts (33.7% and basophils (93.5%. Multivariate analysis revealed a significant relationship between the number of misclassified cells and both the white cell count (p = 0.035 and the presence of malignant cells in the blood (p = 0.049, but not with any other variables analysed, including HIV status. Conclusion: The DM96 exhibited acceptable accuracy in this South African laboratory, which was not impacted by HIV infection. However, as it does not eliminate the need for experienced morphologists, its cost may be unjustifiable in a resource-constrained setting.

  18. Accuracy of Combined Computed Tomography Colonography and Dual Energy Iiodine Map Imaging for Detecting Colorectal masses using High-pitch Dual-source CT.

    Science.gov (United States)

    Sun, Kai; Han, Ruijuan; Han, Yang; Shi, Xuesen; Hu, Jiang; Lu, Bin

    2018-02-28

    To evaluate the diagnostic accuracy of combined computed tomography colonography (CTC) and dual-energy iodine map imaging for detecting colorectal masses using high-pitch dual-source CT, compared with optical colonography (OC) and histopathologic findings. Twenty-eight consecutive patients were prospectively enrolled in this study. All patients were underwent contrast-enhanced CTC acquisition using dual-energy mode and OC and pathologic examination. The size of the space-occupied mass, the CT value after contrast enhancement, and the iodine value were measured and statistically compared. The sensitivity, specificity, accuracy rate, and positive predictive and negative predictive values of dual-energy contrast-enhanced CTC were calculated and compared between conventional CTC and dual-energy iodine images. The iodine value of stool was significantly lower than the colonic neoplasia (P dual-energy iodine maps imaging was 95.6% (95% CI = 77.9%-99.2%). The specificity of the two methods was 42.8% (95% CI = 15.4%-93.5%) and 100% (95% CI = 47.9%-100%; P = 0.02), respectively. Compared with optical colonography and histopathology, combined CTC and dual-energy iodine maps imaging can distinguish stool and colonic neoplasia, distinguish between benign and malignant tumors initially and improve the diagnostic accuracy of CTC for colorectal cancer screening.

  19. Effect of the high-pitch mode in dual-source computed tomography on the accuracy of three-dimensional volumetry of solid pulmonary nodules: A phantom study

    International Nuclear Information System (INIS)

    Hwang, Sung Ho; Oh, Yu Whan; Ham, Soo Youn; Kang, Eun Young; Lee, Ki Yeol

    2015-01-01

    To evaluate the influence of high-pitch mode (HPM) in dual-source computed tomography (DSCT) on the accuracy of three-dimensional (3D) volumetry for solid pulmonary nodules. A lung phantom implanted with 45 solid pulmonary nodules (n = 15 for each of 4-mm, 6-mm, and 8-mm in diameter) was scanned twice, first in conventional pitch mode (CPM) and then in HPM using DSCT. The relative percentage volume errors (RPEs) of 3D volumetry were compared between the HPM and CPM. In addition, the intermode volume variability (IVV) of 3D volumetry was calculated. In the measurement of the 6-mm and 8-mm nodules, there was no significant difference in RPE (p > 0.05, respectively) between the CPM and HPM (IVVs of 1.2 +/- 0.9%, and 1.7 +/- 1.5%, respectively). In the measurement of the 4-mm nodules, the mean RPE in the HPM (35.1 +/- 7.4%) was significantly greater (p < 0.01) than that in the CPM (18.4 +/- 5.3%), with an IVV of 13.1 +/- 6.6%. However, the IVVs were in an acceptable range (< 25%), regardless of nodule size. The accuracy of 3D volumetry with HPM for solid pulmonary nodule is comparable to that with CPM. However, the use of HPM may adversely affect the accuracy of 3D volumetry for smaller (< 5 mm in diameter) nodule.

  20. Effect of the high-pitch mode in dual-source computed tomography on the accuracy of three-dimensional volumetry of solid pulmonary nodules: A phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Sung Ho; Oh, Yu Whan; Ham, Soo Youn [Dept. of Radiology, Korea University Anam Hospital, Seoul (Korea, Republic of); Kang, Eun Young [Dept. of Radiology, Korea University Guro Hospital, Seoul (Korea, Republic of); Lee, Ki Yeol [Dept. of Radiology, Korea University Ansan Hospital, Ansan (Korea, Republic of)

    2015-06-15

    To evaluate the influence of high-pitch mode (HPM) in dual-source computed tomography (DSCT) on the accuracy of three-dimensional (3D) volumetry for solid pulmonary nodules. A lung phantom implanted with 45 solid pulmonary nodules (n = 15 for each of 4-mm, 6-mm, and 8-mm in diameter) was scanned twice, first in conventional pitch mode (CPM) and then in HPM using DSCT. The relative percentage volume errors (RPEs) of 3D volumetry were compared between the HPM and CPM. In addition, the intermode volume variability (IVV) of 3D volumetry was calculated. In the measurement of the 6-mm and 8-mm nodules, there was no significant difference in RPE (p > 0.05, respectively) between the CPM and HPM (IVVs of 1.2 +/- 0.9%, and 1.7 +/- 1.5%, respectively). In the measurement of the 4-mm nodules, the mean RPE in the HPM (35.1 +/- 7.4%) was significantly greater (p < 0.01) than that in the CPM (18.4 +/- 5.3%), with an IVV of 13.1 +/- 6.6%. However, the IVVs were in an acceptable range (< 25%), regardless of nodule size. The accuracy of 3D volumetry with HPM for solid pulmonary nodule is comparable to that with CPM. However, the use of HPM may adversely affect the accuracy of 3D volumetry for smaller (< 5 mm in diameter) nodule.