WorldWideScience

Sample records for time resolution performance

  1. Time resolution performance studies of contemporary high speed photomultipliers

    International Nuclear Information System (INIS)

    Leskovar, B.; Lo, C.C.

    1977-01-01

    The time resolution capabilities of prototype microchannel plate and static crossed-field photomultipliers have been investigated. Measurements were made of electron transit time, rise time, time response, single photoelectron time spread and multiphotoelectron time spread for LEP HR350 proximity focused high gain curved microchannel plate and VPM-154A/1.6L static crossed-field photomultipliers. The experimental data have been compared with results obtained with conventionally designed RCS 8850 and C31024 high speed photomultipliers. Descriptions are given of both the measuring techniques and the measuring systems

  2. Characterisation and exploitation of Atlas electromagnetic calorimeter performances: muons study and timing resolution use

    International Nuclear Information System (INIS)

    Camard, A.

    2004-10-01

    The ATLAS detector in LHC involves electromagnetic calorimeters. The purpose of this work is to study the calorimeter response to the muons contaminating the beam used to test the different modules of ATLAS. We have showed how data analysis from the testing beam can be used to assure that the required performance for the study of the detector response to muons provides a complementary diagnostic tool for electrons. We have taken part into the design of a testing bench aimed at assessing the performance of the receiver circuit for timing and triggering signals. We have developed, in the framework of a quick simulation of ATLAS, a tool for the reconstruction in a simple and fast manner of the localization of the main event vertex by using the measurement of the arrival time of particles with ATLAS's calorimeters. It is likely that this tool will be fully used during the starting phase of the ATLAS experiment because it is easier to operate it quickly and is less sensitive to the background noise than traditional tools based on charged-particle tracks recognition inside the detector

  3. High Time Resolution Astrophysics

    CERN Document Server

    Phelan, Don; Shearer, Andrew

    2008-01-01

    High Time Resolution Astrophysics (HTRA) is an important new window to the universe and a vital tool in understanding a range of phenomena from diverse objects and radiative processes. This importance is demonstrated in this volume with the description of a number of topics in astrophysics, including quantum optics, cataclysmic variables, pulsars, X-ray binaries and stellar pulsations to name a few. Underlining this science foundation, technological developments in both instrumentation and detectors are described. These instruments and detectors combined cover a wide range of timescales and can measure fluxes, spectra and polarisation. These advances make it possible for HTRA to make a big contribution to our understanding of the Universe in the next decade.

  4. Design and Implementation of a Real-time Processing System of Full Resolution Quick-look Image of HJ-1 Environmental Satellite C SAR Based on High Performance Cluster

    Directory of Open Access Journals (Sweden)

    Li Jing-shan

    2014-06-01

    Full Text Available This study is concerned with the design and implementation of a real-time processing system of full resolution quick-look image of HJ-1 environmental satellite C SAR based on high-performance clusters. The system processes the first quick-look SAR image on December 9, 2012. The results show that the design and implementation of the quick-look processing system satisfies the real-time SAR image processing performance requirements at full resolution. Moreover, this system is the first real-time business system of full-resolution quick-look spaceborne SAR images in China.

  5. Characterisation and exploitation of Atlas electromagnetic calorimeter performances: muons study and timing resolution use; Caracterisation et exploitation des performances du calorimetre electromagneique d'Atlas: etude des muons et mise a profit de la resolution en temps

    Energy Technology Data Exchange (ETDEWEB)

    Camard, A

    2004-10-01

    The ATLAS detector in LHC involves electromagnetic calorimeters. The purpose of this work is to study the calorimeter response to the muons contaminating the beam used to test the different modules of ATLAS. We have showed how data analysis from the testing beam can be used to assure that the required performance for the study of the detector response to muons provides a complementary diagnostic tool for electrons. We have taken part into the design of a testing bench aimed at assessing the performance of the receiver circuit for timing and triggering signals. We have developed, in the framework of a quick simulation of ATLAS, a tool for the reconstruction in a simple and fast manner of the localization of the main event vertex by using the measurement of the arrival time of particles with ATLAS's calorimeters. It is likely that this tool will be fully used during the starting phase of the ATLAS experiment because it is easier to operate it quickly and is less sensitive to the background noise than traditional tools based on charged-particle tracks recognition inside the detector.

  6. A method for coincidence timing resolution enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Ermis, E. E., E-mail: elermis@hotmail.com; Celiktas, C. [Faculty of Science, Physics Department, Ege University, 35100 Bornova, Izmir (Turkey); Pilicer, E. [Faculty of Arts and Science, Physics Department, Uludag University, Gorukle, Bursa (Turkey)

    2016-05-15

    A method including the coincidence time resolution improvement for a TOF/positron emission tomography system was suggested. The spectrometer for this aim was composed of two NaI(Tl) and two plastic scintillation detectors. Experimental results were supported by FLUKA Monte Carlo simulation program by constructing the detector setup in software medium. Present experimental results verified our previous results and conclusions obtained from the suggested method. It was concluded that better resolutions would help the improvement not only on the TOF gain but also on the spatial resolution, leading to better images and helping the Physician in his/her diagnosis and treatment.

  7. 10 ps resolution, 160 ns full scale range and less than 1.5% differential non-linearity time-to-digital converter module for high performance timing measurements

    Energy Technology Data Exchange (ETDEWEB)

    Markovic, B.; Tamborini, D.; Villa, F.; Tisa, S.; Tosi, A.; Zappa, F. [Politecnico di Milano, Dipartimento di Elettronica e Informazione, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2012-07-15

    We present a compact high performance time-to-digital converter (TDC) module that provides 10 ps timing resolution, 160 ns dynamic range and a differential non-linearity better than 1.5% LSB{sub rms}. The TDC can be operated either as a general-purpose time-interval measurement device, when receiving external START and STOP pulses, or in photon-timing mode, when employing the on-chip SPAD (single photon avalanche diode) detector for detecting photons and time-tagging them. The instrument precision is 15 ps{sub rms} (i.e., 36 ps{sub FWHM}) and in photon timing mode it is still better than 70 ps{sub FWHM}. The USB link to the remote PC allows the easy setting of measurement parameters, the fast download of acquired data, and their visualization and storing via an user-friendly software interface. The module proves to be the best candidate for a wide variety of applications such as: fluorescence lifetime imaging, time-of-flight ranging measurements, time-resolved positron emission tomography, single-molecule spectroscopy, fluorescence correlation spectroscopy, diffuse optical tomography, optical time-domain reflectometry, quantum optics, etc.

  8. Silicon photomultiplier timing performance study

    Science.gov (United States)

    Gamal, Ahmed; Paul, Bühler; Johann, Marton; Ken, Suzuki

    2011-10-01

    Many characteristics of Silicon Photomultipliers can be tuned with temperature and operation voltage. We present preliminary results of a study of the effect of these two operation parameters on the time resolution of large active area Multi-Pixel Photon Counters (MPPCs) manufactured by Hamamatsu. Measurements at -10, 0, and 10 °C at different bias voltages were performed. The time resolution is best at low temperature and high over-voltage. Most significant improvements can be achieved in cases with low number of fired pixels (40 pixels) the effect of temperature and operation voltage becomes smaller. The timing performance still improves with decreasing temperature ( ≈factor of 2) but it hardly depends on the operation voltage. The study shows that especially in applications where only few photons are available for detection a careful optimization of temperature and operation voltage are advisable to obtain optimum timing results with the MPPC.

  9. Time resolution research in liquid scintillating detection

    International Nuclear Information System (INIS)

    He Hongkun; Shi Haoshan

    2006-01-01

    The signal processing design method is introduced into liquid scintillating detection system design. By analyzing the signal of liquid scintillating detection, improving time resolution is propitious to upgrade efficiency of detecting. The scheme of realization and satisfactory experiment data is demonstrated. Besides other types of liquid scintillating detection is the same, just using more high speed data signal processing techniques and elements. (authors)

  10. On Time Performance Pressure

    Science.gov (United States)

    Connell, Linda; Wichner, David; Jakey, Abegael

    2013-01-01

    Within many operations, the pressures for on-time performance are high. Each month, on-time statistics are reported to the Department of Transportation and made public. There is a natural tendency for employees under pressure to do their best to meet these objectives. As a result, pressure to get the job done within the allotted time may cause personnel to deviate from procedures and policies. Additionally, inadequate or unavailable resources may drive employees to work around standard processes that are seen as barriers. However, bypassing practices to enable on-time performance may affect more than the statistics. ASRS reports often highlight on-time performance pressures which may result in impact across all workgroups in an attempt to achieve on-time performance. Reporters often provide in-depth insights into their experiences which can be used by industry to identify and focus on the implementation of systemic fixes.

  11. Analysis of Time Resolution in HGCAL Testbeam

    CERN Document Server

    Steentoft, Jonas

    2017-01-01

    Using data from a 250 GeV electron run during the November 2016 HGCAL testbeam, the time resolution of the High Granularity hadronic endcap Calorimeter, HGCAL, was investigated, looking at the seven innermost Si cells, and using them as reference timers for each other. Cuts in the data was applied based on signal amplitude,$0.05 \\hspace{1mm} V < A < 0.45 \\hspace{1mm} V$, position of incoming beam particle,$0 \\hspace{1mm} mm < TDCx < 22\\hspace{1mm} mm$ and $-7\\hspace{1mm} mm time difference between two cells, $\\vert t_1 - t_2 \\vert < 200 \\hspace{1mm} ps.$ Timewalk corrections, wrt in-cell amplitude, were applied to the cut data, with the Photek as reference.\\\\ Gaussian functions were fitted to the corrected $\\Delta t$ distributions, and a time resolution of $15-50$ $ps$ was obtained, depending on which two cells were compared, and how the low-statistics cut were placed. We also confirmed a slight correlation between time resolution and distanc...

  12. A new timing model for calculating the intrinsic timing resolution of a scintillator detector

    International Nuclear Information System (INIS)

    Shao Yiping

    2007-01-01

    The coincidence timing resolution is a critical parameter which to a large extent determines the system performance of positron emission tomography (PET). This is particularly true for time-of-flight (TOF) PET that requires an excellent coincidence timing resolution (<<1 ns) in order to significantly improve the image quality. The intrinsic timing resolution is conventionally calculated with a single-exponential timing model that includes two parameters of a scintillator detector: scintillation decay time and total photoelectron yield from the photon-electron conversion. However, this calculation has led to significant errors when the coincidence timing resolution reaches 1 ns or less. In this paper, a bi-exponential timing model is derived and evaluated. The new timing model includes an additional parameter of a scintillator detector: scintillation rise time. The effect of rise time on the timing resolution has been investigated analytically, and the results reveal that the rise time can significantly change the timing resolution of fast scintillators that have short decay time constants. Compared with measured data, the calculations have shown that the new timing model significantly improves the accuracy in the calculation of timing resolutions

  13. A multi-channel high-resolution time recorder system

    International Nuclear Information System (INIS)

    Zhang Lingyun; Yang Xiaojun; Song Kezhu; Wang Yanfang

    2004-01-01

    This paper introduces a multi-channel and high-speed time recorder system, which was originally designed to work in the experiments of quantum cryptography research. The novelty of the system is that all the hardware logic is performed by only one FPGA. The system can achieve several desirable features, such as simplicity, high resolution and high processing speed. (authors)

  14. Super-resolution Time-Lapse Seismic Waveform Inversion

    Science.gov (United States)

    Ovcharenko, O.; Kazei, V.; Peter, D. B.; Alkhalifah, T.

    2017-12-01

    Time-lapse seismic waveform inversion is a technique, which allows tracking changes in the reservoirs over time. Such monitoring is relatively computationally extensive and therefore it is barely feasible to perform it on-the-fly. Most of the expenses are related to numerous FWI iterations at high temporal frequencies, which is inevitable since the low-frequency components can not resolve fine scale features of a velocity model. Inverted velocity changes are also blurred when there is noise in the data, so the problem of low-resolution images is widely known. One of the problems intensively tackled by computer vision research community is the recovering of high-resolution images having their low-resolution versions. Usage of artificial neural networks to reach super-resolution from a single downsampled image is one of the leading solutions for this problem. Each pixel of the upscaled image is affected by all the pixels of its low-resolution version, which enables the workflow to recover features that are likely to occur in the corresponding environment. In the present work, we adopt machine learning image enhancement technique to improve the resolution of time-lapse full-waveform inversion. We first invert the baseline model with conventional FWI. Then we run a few iterations of FWI on a set of the monitoring data to find desired model changes. These changes are blurred and we enhance their resolution by using a deep neural network. The network is trained to map low-resolution model updates predicted by FWI into the real perturbations of the baseline model. For supervised training of the network we generate a set of random perturbations in the baseline model and perform FWI on the noisy data from the perturbed models. We test the approach on a realistic perturbation of Marmousi II model and demonstrate that it outperforms conventional convolution-based deblurring techniques.

  15. Silicon photomultiplier timing performance study

    Energy Technology Data Exchange (ETDEWEB)

    Gamal, Ahmed, E-mail: gamal.ahmed@assoc.oeaw.ac.at [Stefan Meyer Institute for Subatomic Physics of the Austrian Academy of Sciences, Vienna (Austria); Al-Azhar University, Faculty of Science, Physics Department, Cairo (Egypt); Paul, Buehler; Johann, Marton; Ken, Suzuki [Stefan Meyer Institute for Subatomic Physics of the Austrian Academy of Sciences, Vienna (Austria)

    2011-10-01

    Many characteristics of Silicon Photomultipliers can be tuned with temperature and operation voltage. We present preliminary results of a study of the effect of these two operation parameters on the time resolution of large active area Multi-Pixel Photon Counters (MPPCs) manufactured by Hamamatsu. Measurements at -10, 0, and 10 deg. C at different bias voltages were performed. The time resolution is best at low temperature and high over-voltage. Most significant improvements can be achieved in cases with low number of fired pixels (<10pixels). Between the worst and best case among the considered conditions a factor of five improvement was observed. In cases with large number of fired pixels (>40pixels) the effect of temperature and operation voltage becomes smaller. The timing performance still improves with decreasing temperature ({approx}factor of 2) but it hardly depends on the operation voltage. The study shows that especially in applications where only few photons are available for detection a careful optimization of temperature and operation voltage are advisable to obtain optimum timing results with the MPPC.

  16. Keeping time - Performing Place

    DEFF Research Database (Denmark)

    Dvinge, Anne Christine

    2012-01-01

    Candace Allen’s novel Valaida (2004) illustrates the migratory patterns of early 20th century jazz music and musicians, positing the art form and its performers as “heterotopians”; simultaneously in and outside of the power relations of hegemonic time-space compression, travelling in an alternate...... and progressive space, signified by the music. However, through a reading of heterotopic spaces in Valaida, this article seeks to complicate the notion of heterotopias as purely progressive spaces for reversal and liberation. It does so by emphasizing the double nature of heterotopias as both progressive...... and reactionary and suggests that the way time is employed in a heterotopic space determines its progressive potential. Spaces of accumulative, static, or frozen time refuse to yield any utopian promise, whereas fluid, dynamic, and ephemeral time offers moments of agency. In the case of Valaida, music...

  17. Real time SQUID dynamics revealed using high resolution cryogenic sampler

    International Nuclear Information System (INIS)

    Faris, S.M.; Pedersen, N.F.

    1981-01-01

    Real time measurements of SQUID dynamics have been performed using a fast cryogenic sampler based on Josephson junction electronics. Complex waveforms representing the switching of a SQUID from one voltage state to another are obtained with time and current resolution of 10 ps and 1 μA, respectively. With this setup, it is possible to demonstrate the interaction between the internal SQUID dynamics (resonances) and the load. The interaction depends on the details of the bias and control currents. (orig.)

  18. Time-reversal waves and super resolution

    Energy Technology Data Exchange (ETDEWEB)

    Fink, M [Laboratoire Ondes et Acoustique, Ecole Suprieure de Physique et de Chimie Industrielle de la Ville de Paris, Universit Denis Diderot, UMR CNRS 7587, 10 Rue Vauquelin, 75005 Paris (France)], E-mail: mathias.fink@espci.fr

    2008-07-15

    Time-reversal mirrors (TRMs) refocus an incident acoustic field to the position of the original source regardless of the complexity of the propagation medium. TRM's have now been implemented in a variety of physical scenarios from MHz ultrasonics with order centimeter aperture size to hundreds/thousands of Hz in ocean acoustics with order hundred meter aperture size. Common to this broad range of scales is a remarkable robustness exemplified by observations at all scales that the more complex the medium between the probe source and the TRM, the sharper the focus. The relation between the medium complexity and the size of the focal spot is studied in this paper. It is certainly the most exciting property of TRM compared to standard focusing devices. A TRM acts as an antenna that uses complex environments to appears wider than it is, resulting for a broadband pulse in a refocusing quality that does not depend of the TRM aperture. In this paper, we investigate the time-reversal approach in various media of increasing complexity We will also demonstrated that time-reversal focusing opens completely new approaches to super-resolution. We will show that in medium made of random distribution of sub-wavelength scatterers, a time-reversed wave field interacts with the random medium to regenerate not only the propagating but also the evanescent waves required to refocus below the diffraction limit. Finally, we will discuss the link existing between time-reversal approaches and new imaging methods recently developed where Green's functions of complex media can be extracted from diffusive noise by cross-correlating the recordings of a diffuse random wave field.

  19. Time stamping of single optical photons with 10 ns resolution

    Science.gov (United States)

    Chakaberia, Irakli; Cotlet, Mircea; Fisher-Levine, Merlin; Hodges, Diedra R.; Nguyen, Jayke; Nomerotski, Andrei

    2017-05-01

    High spatial and temporal resolution are key features for many modern applications, e.g. mass spectrometry, probing the structure of materials via neutron scattering, studying molecular structure, etc.1-5 Fast imaging also provides the capability of coincidence detection, and the further addition of sensitivity to single optical photons with the capability of timestamping them further broadens the field of potential applications. Photon counting is already widely used in X-ray imaging,6 where the high energy of the photons makes their detection easier. TimepixCam is a novel optical imager,7 which achieves high spatial resolution using an array of 256×256 55 μm × 55μm pixels which have individually controlled functionality. It is based on a thin-entrance-window silicon sensor, bump-bonded to a Timepix ASIC.8 TimepixCam provides high quantum efficiency in the optical wavelength range (400-1000 nm). We perform the timestamping of single photons with a time resolution of 20 ns, by coupling TimepixCam to a fast image-intensifier with a P47 phosphor screen. The fast emission time of the P479 allows us to preserve good time resolution while maintaining the capability to focus the optical output of the intensifier onto the 256×256 pixel Timepix sensor area. We demonstrate the capability of the (TimepixCam + image intensifier) setup to provide high-resolution single-photon timestamping, with an effective frame rate of 50 MHz.

  20. Energy Resolution Performance of the CMS Electromagnetic Calorimeter

    CERN Document Server

    Adzic, Petar; Almeida, Carlos; Almeida, Nuno; Anagnostou, Georgios; Anfreville, Marc; Anicin, Ivan; Antunovic, Zeljko; Auffray, Etiennette; Baccaro, Stefania; Baffioni, Stephanie; Barney, David; Barone, Luciano; Barrillon, Pierre; Bartoloni, Alessandro; Beauceron, Stephanie; Beaudette, Florian; Bell, Ken W; Benetta, Robert; Bercher, Michel; Berthon, Ursula; Betev, Botjo; Beuselinck, Raymond; Bhardwaj, Ashutosh; Biino, Cristina; Bimbot, Stephane; Blaha, Jan; Bloch, Philippe; Blyth, Simon; Bordalo, Paula; Bornheim, Adolf; Bourotte, Jean; Britton1, D; Brown, Robert M; Brunelière, Renaud; Busson, Philippe; Camporesi, Tiziano; Cartiglia, Nicolo; Cavallari, Francesca; Cerutti, Muriel; Chamont, David; Chang, Paoti; Chang, You-Hao; Charlot, Claude; Chatterji, Sudeep; Chen, E Augustine; Chipaux, Rémi; Choudhary, Brajesh C; Cockerill, David J A; Collard, Caroline; Combaret, Christophe; Cossutti, Fabio; Costantini, Silvia; Da Silva, J C; Dafinei, Ioan; Daskalakis, Georgios; Davatz, Giovanna; Debraine, Alain; Decotigny, David; De Min, Alberto; Deiters, Konrad; Dejardin, Marc; Della Negra, Rodolphe; Della Ricca, Giuseppe; Depasse, Pierre; Descamp, J; Dewhirst, Guy; Dhawan, Satish; Diemoz, Marcella; Dissertori, Günther; Dittmar, Michael; Djambazov, Lubomir; Dobrzynski, Ludwik; Drndarevic, Snezana; Dupanloup, Michel; Dzelalija, Mile; Ehlers, Jan; El-Mamouni, H; Peisert, Anna; Evangelou, Ioannis; Fabbro, Bernard; Faure, Jean-Louis; Fay, Jean; Ferri, Federico; Flower, Paul S; Franzoni, Giovanni; Funk, Wolfgang; Gaillac, Anne-Marie; Gargiulo, Corrado; Gascon-Shotkin, S; Geerebaert, Yannick; Gentit, François-Xavier; Ghezzi, Alessio; Gilly, Jean; Giolo-Nicollerat, Anne-Sylvie; Givernaud, Alain; Gninenko, Sergei; Go, Apollo; Godinovic, Nikola; Golubev, Nikolai; Golutvin, Igor; Gómez-Reino, Robert; Govoni, Pietro; Grahl1, J; Gras1, P; Greenhalgh, Justin; Guillaud, Jean-Paul; Haguenauer, Maurice; Hamel-de-Montechenault, G; Hansen, Magnus; Heath, Helen F; AHill, J; Hobson, Peter R; Holmes, Daniel; Holzner, André; Hou, George Wei-Shu; Ille, Bernard; Ingram, Quentin; Jain, Adarsh; Jarry, Patrick; Jauffret, C; Jha, Manoj; Karar, Akli; Kataria, Sushil Kumar; Katchanov, V A; Kennedy, Bruce W; Kloukinas, Kostas; Kokkas, Panagiotis; Korjik, M; Krasnikov, Nikolai; Krpic, Dragomir; Kyriakis, Aristotelis; Lebeau, Michel; Lecomte, Pierre; Lecoq, Paul; Lemaire, Marie-Claude; Lethuillier, Morgan; Lin, Willis; Lintern, A L; Lister, Alison; Litvin, V; Locci, Elizabeth; Lodge, Anthony B; Longo, Egidio; Loukas, Demetrios; Luckey, D; Lustermann, Werner; Lynch, Clare; MacKay, Catherine Kirsty; Malberti, Martina; Maletic, Dimitrije; Mandjavidze, Irakli; Manthos, Nikolaos; Markou, Athanasios; Mathez, Hervé; Mathieu, Antoine; Matveev, Viktor; Maurelli, Georges; Menichetti, Ezio; Meridiani, Paolo; Milenovic, Predrag; Milleret, Gérard; Miné, Philippe; Mur, Michel; Musienko, Yuri; Nardulli, Alessandro; Nash, Jordan; Neal, Homer; Nédélec, Patrick; Negri, Pietro; Nessi-Tedaldi, Francesca; Newman26, H B; Nikitenko, Alexander; Obertino, Maria Margherita; Ofierzynski, Radoslaw Adrian; Organtini, Giovanni; Paganini, Pascal; Paganoni, Marco; Papadopoulos, Ioannis; Paramatti, Riccardo; Pastrone, Nadia; Pauss, Felicitas; Poilleux, Patrick; Puljak, Ivica; Pullia, Antonino; Puzovic, Jovan; Ragazzi, Stefano; Ramos, Sergio; Rahatlou, Shahram; Rander, John; Ranjan, Kirti; Ravat, Olivier; Raymond, M; Razis, Panos A; Redaelli, Nicola; Renker, Dieter; Reucroft, Steve; Reymond, Jean-Marc; Reynaud, Michel; Reynaud, Serge; Romanteau, Thierry; Rondeaux, Françoise; Rosowsky, André; Rovelli, Chiara; Rumerio, Paolo; Rusack, Roger; Rusakov, Sergey V; Ryan, Matthew John; Rykaczewski, Hans; Sakhelashvili, Tariel; Salerno, Roberto; Santos, Marcelino; Seez, Christopher; Semeniouk, Igor; Sharif, Omar; Sharp, Peter; Shepherd-Themistocleous, Claire; Shevchenko, Sergey; Shivpuri, Ram Krishen; Sidiropoulos, Georgios; Sillou, Daniel; Singovsky, Alexander; Sirois, Yves; Sirunyan, Albert M; Smith, Brian; Smith, Vincent J; Sproston, Martin; Suter, Henry; Swain, John; Tabarelli de Fatis, Tommaso; Takahashi, Maiko; Tapper, Robert J; Tcheremoukhine, Alexandre; Teixeira, Isabel; Teixeira, Joao Paulo; Teller, Olivier; Timlin, Claire; ATriantis, F; Troshin, Sergey; Tyurin, Nikolay; Ueno, Koji; Uzunian, Andrey; Varela, Joao; Vaz-Cardoso, N; Verrecchia, Patrice; Vichoudis, Paschalis; Vigano, S; Viertel, Gert; Virdee, Tejinder; Vlassov, E; Wang, Minzu; Weinstein, Alan; Williams, Jennifer C; Yaselli, Ignacio; Zabi, Alexandre; Zamiatin, Nikolai; Zelepoukine, Serguei; Zeller, Michael E; Zhang, Lin; Zhang, Yawei; Zhu, Kejun; Zhu, Ren-Yuan

    2006-01-01

    The energy resolution performance of the CMS lead tungstate crystal electromagnetic calorimeter is presented. Measurements were made with an electron beam using a fully equipped supermodule of the calorimeter barrel. Results are given both for electrons incident on the centre of crystals and for electrons distributed uniformly over the calorimeter surface. The electron energy is reconstructed in matrices of 3 times 3 or 5 times 5 crystals centred on the crystal containing the maximum energy. Corrections for variations in the shower containment are applied in the case of uniform incidence. The resolution measured is consistent with the design goals.

  1. High resolution time-of-flight electronics system

    International Nuclear Information System (INIS)

    Grund, J.E.

    1979-10-01

    A new electronics system for time-of-flight measurements has been developed to meet the performance requirements of the Mark II Detector for operation at the PEP Storage Ring of the Stanford Linear Accelerator Center. This system incorporated high resolution time measurements with the capability to correct systemic errors from the scintillator and photomultiplier tubes. The correction technique involves making three measurements on each photomultiplier signal every storage ring beam interaction. Two timing measurements are made relative to the beam interaction time with different discriminator threshold level settings. The charge integral of each photomultiplier pulse is also recorded

  2. High time-resolution sprite observations

    Science.gov (United States)

    Stenbaek-Nielsen, H. C.; McHarg, G. G.

    2007-12-01

    Imaging sprites at 10,000 fps have revealed new details about their temporal development. TV observations show a highly structured central body with downward tendrils and upward branches. But rather than being leaders, as suggested by the long streaks in the TV recordings, tendrils and branches are actually formed by spatially compact streamer heads moving at velocities up to 0.3 c. In an individual sprite event the downward moving streamer heads start first forming the tendrils; later, and from a lower altitude and from existing luminous sprite structures, upward moving streamer heads may appear to form the branches. If there are no upward moving streamer heads the event would be classified as a C-sprite, otherwise it would be a carrot sprite. Following the streamer head activity we see afterglow in which little or no temporal and spatial activity is present. The streamer heads are very bright and they appear to be point sources, i.e. their spatial dimensions are less than our 100-200 m image resolution. Streamer head modeling indicates a scale size of ~25 m in which case the brightness would be in the range 1-100 GR. Other models predict volume emission rates leading to a streamer head spatial scale size in the 10 to 100 m range. Our observations conclusively show the downward and upward propagating streamer heads to be separated in time and space. This is in contrast to a number of models in which both down and up going streamer heads emanates from the origin of the process. We frequently see old sprites re-appear in response to new activity suggesting that sprite activity leaves some imprint on the background atmosphere. Given the very large brightness of the streamer heads it would not be surprising if sprite activity initiates chemical processes that could locally affect the composition of the atmosphere, but whether this affects the mesosphere on a larger scale remains uncertain.

  3. 3D detectors with high space and time resolution

    Science.gov (United States)

    Loi, A.

    2018-01-01

    For future high luminosity LHC experiments it will be important to develop new detector systems with increased space and time resolution and also better radiation hardness in order to operate in high luminosity environment. A possible technology which could give such performances is 3D silicon detectors. This work explores the possibility of a pixel geometry by designing and simulating different solutions, using Sentaurus Tecnology Computer Aided Design (TCAD) as design and simulation tool, and analysing their performances. A key factor during the selection was the generated electric field and the carrier velocity inside the active area of the pixel.

  4. arXiv Time resolution of silicon pixel sensors

    CERN Document Server

    Riegler, W.

    2017-11-21

    We derive expressions for the time resolution of silicon detectors, using the Landau theory and a PAI model for describing the charge deposit of high energy particles. First we use the centroid time of the induced signal and derive analytic expressions for the three components contributing to the time resolution, namely charge deposit fluctuations, noise and fluctuations of the signal shape due to weighting field variations. Then we derive expressions for the time resolution using leading edge discrimination of the signal for various electronics shaping times. Time resolution of silicon detectors with internal gain is discussed as well.

  5. Performance evaluation of a high resolution dedicated breast PET scanner

    Energy Technology Data Exchange (ETDEWEB)

    García Hernández, Trinitat, E-mail: mtrinitat@eresa.com; Vicedo González, Aurora; Brualla González, Luis; Granero Cabañero, Domingo [Department of Medical Physics, ERESA, Hospital General Universitario, Valencia 46014 (Spain); Ferrer Rebolleda, Jose; Sánchez Jurado, Raúl; Puig Cozar Santiago, Maria del [Department of Nuclear Medicine, ERESA, Hospital General Universitario, Valencia 46014 (Spain); Roselló Ferrando, Joan [Department of Medical Physics, ERESA, Hospital General Universitario, Valencia 46014 (Spain); Department of Physiology, University of Valencia, Valencia 46010 (Spain)

    2016-05-15

    Purpose: Early stage breast cancers may not be visible on a whole-body PET scan. To overcome whole-body PET limitations, several dedicated breast positron emission tomography (DbPET) systems have emerged nowadays aiming to improve spatial resolution. In this work the authors evaluate the performance of a high resolution dedicated breast PET scanner (Mammi-PET, Oncovision). Methods: Global status, uniformity, sensitivity, energy, and spatial resolution were measured. Spheres of different sizes (2.5, 4, 5, and 6 mm diameter) and various 18 fluorodeoxyglucose ({sup 18}F-FDG) activity concentrations were randomly inserted in a gelatine breast phantom developed at our institution. Several lesion-to-background ratios (LBR) were simulated, 5:1, 10:1, 20:1, 30:1, and 50:1. Images were reconstructed using different voxel sizes. The ability of experienced reporters to detect spheres was tested as a function of acquisition time, LBR, sphere size, and matrix reconstruction voxel size. For comparison, phantoms were scanned in the DbPET camera and in a whole body PET (WB-PET). Two patients who just underwent WB-PET/CT exams were imaged with the DbPET system and the images were compared. Results: The measured absolute peak sensitivity was 2.0%. The energy resolution was 24.0% ± 1%. The integral and differential uniformity were 10% and 6% in the total field of view (FOV) and 9% and 5% in the central FOV, respectively. The measured spatial resolution was 2.0, 1.9, and 1.7 mm in the radial, tangential, and axial directions. The system exhibited very good detectability for spheres ≥4 mm and LBR ≥10 with a sphere detection of 100% when acquisition time was set >3 min/bed. For LBR = 5 and acquisition time of 7 min the detectability was 100% for spheres of 6 mm and 75% for spheres of 5, 4, and 2.5 mm. Lesion WB-PET detectability was only comparable to the DbPET camera for lesion sizes ≥5 mm when acquisition time was >3 min and LBR > 10. Conclusions: The DbPET has a good

  6. Performance evaluation of a high resolution dedicated breast PET scanner

    International Nuclear Information System (INIS)

    García Hernández, Trinitat; Vicedo González, Aurora; Brualla González, Luis; Granero Cabañero, Domingo; Ferrer Rebolleda, Jose; Sánchez Jurado, Raúl; Puig Cozar Santiago, Maria del; Roselló Ferrando, Joan

    2016-01-01

    Purpose: Early stage breast cancers may not be visible on a whole-body PET scan. To overcome whole-body PET limitations, several dedicated breast positron emission tomography (DbPET) systems have emerged nowadays aiming to improve spatial resolution. In this work the authors evaluate the performance of a high resolution dedicated breast PET scanner (Mammi-PET, Oncovision). Methods: Global status, uniformity, sensitivity, energy, and spatial resolution were measured. Spheres of different sizes (2.5, 4, 5, and 6 mm diameter) and various 18 fluorodeoxyglucose ( 18 F-FDG) activity concentrations were randomly inserted in a gelatine breast phantom developed at our institution. Several lesion-to-background ratios (LBR) were simulated, 5:1, 10:1, 20:1, 30:1, and 50:1. Images were reconstructed using different voxel sizes. The ability of experienced reporters to detect spheres was tested as a function of acquisition time, LBR, sphere size, and matrix reconstruction voxel size. For comparison, phantoms were scanned in the DbPET camera and in a whole body PET (WB-PET). Two patients who just underwent WB-PET/CT exams were imaged with the DbPET system and the images were compared. Results: The measured absolute peak sensitivity was 2.0%. The energy resolution was 24.0% ± 1%. The integral and differential uniformity were 10% and 6% in the total field of view (FOV) and 9% and 5% in the central FOV, respectively. The measured spatial resolution was 2.0, 1.9, and 1.7 mm in the radial, tangential, and axial directions. The system exhibited very good detectability for spheres ≥4 mm and LBR ≥10 with a sphere detection of 100% when acquisition time was set >3 min/bed. For LBR = 5 and acquisition time of 7 min the detectability was 100% for spheres of 6 mm and 75% for spheres of 5, 4, and 2.5 mm. Lesion WB-PET detectability was only comparable to the DbPET camera for lesion sizes ≥5 mm when acquisition time was >3 min and LBR > 10. Conclusions: The DbPET has a good performance

  7. High-resolution twin-ion metabolite extraction (HiTIME) mass spectrometry: nontargeted detection of unknown drug metabolites by isotope labeling, liquid chromatography mass spectrometry, and automated high-performance computing.

    Science.gov (United States)

    Leeming, Michael G; Isaac, Andrew P; Pope, Bernard J; Cranswick, Noel; Wright, Christine E; Ziogas, James; O'Hair, Richard A J; Donald, William A

    2015-04-21

    The metabolic fate of a compound can often determine the success of a new drug lead. Thus, significant effort is directed toward identifying the metabolites formed from a given molecule. Here, an automated and nontargeted procedure is introduced for detecting drug metabolites without authentic metabolite standards via the use of stable isotope labeling, liquid chromatography mass spectrometry (LC/MS), and high-performance computing. LC/MS of blood plasma extracts from rats that were administered a 1:1 mixture of acetaminophen (APAP) and (13)C6-APAP resulted in mass spectra that contained "twin" ions for drug metabolites that were not detected in control spectra (i.e., no APAP administered). Because of the development of a program (high-resolution twin-ion metabolite extraction; HiTIME) that can identify twin-ions in high-resolution mass spectra without centroiding (i.e., reduction of mass spectral peaks to single data points), 9 doublets corresponding to APAP metabolites were identified. This is nearly twice that obtained by use of existing programs that make use of centroiding to reduce computational cost under these conditions with a quadrupole time-of-flight mass spectrometer. By a manual search for all reported APAP metabolite ions, no additional twin-ion signals were assigned. These data indicate that all the major metabolites of APAP and multiple low-abundance metabolites (e.g., acetaminophen hydroxy- and methoxysulfate) that are rarely reported were detected. This methodology can be used to detect drug metabolites without prior knowledge of their identity. HiTIME is freely available from https://github.com/bjpop/HiTIME .

  8. High resolution time integration for Sn radiation transport

    International Nuclear Information System (INIS)

    Thoreson, Greg; McClarren, Ryan G.; Chang, Jae H.

    2008-01-01

    First order, second order and high resolution time discretization schemes are implemented and studied for the S n equations. The high resolution method employs a rate of convergence better than first order, but also suppresses artificial oscillations introduced by second order schemes in hyperbolic differential equations. All three methods were compared for accuracy and convergence rates. For non-absorbing problems, both second order and high resolution converged to the same solution as the first order with better convergence rates. High resolution is more accurate than first order and matches or exceeds the second order method. (authors)

  9. ASIC-enabled High Resolution Optical Time Domain Reflectometer

    Science.gov (United States)

    Skendzic, Sandra

    Fiber optics has become the preferred technology in communication systems because of what it has to offer: high data transmission rates, immunity to electromagnetic interference, and lightweight, flexible cables. An optical time domain reflectometer (OTDR) provides a convenient method of locating and diagnosing faults (e.g. break in a fiber) along a fiber that can obstruct crucial optical pathways. Both the ability to resolve the precise location of the fault and distinguish between two discrete, closely spaced faults are figures of merit. This thesis presents an implementation of a high resolution OTDR through the use of a compact and programmable ASIC (application specific integrated circuit). The integration of many essential OTDR functions on a single chip is advantageous over existing commercial instruments because it enables small, lightweight packaging, and offers low power and cost efficiency. Furthermore, its compactness presents the option of placing multiple ASICs in parallel, which can conceivably ease the characterization of densely populated fiber optic networks. The OTDR ASIC consists of a tunable clock, pattern generator, precise timer, electrical receiver, and signal sampling circuit. During OTDR operation, the chip generates narrow electrical pulse, which can then be converted to optical format when coupled with an external laser diode driver. The ASIC also works with an external photodetector to measure the timing and amplitude of optical reflections in a fiber. It has a 1 cm sampling resolution, which allows for a 2 cm spatial resolution. While this OTDR ASIC has been previously demonstrated for multimode fiber fault diagnostics, this thesis focuses on extending its functionality to single mode fiber. To validate this novel approach to OTDR, this thesis is divided into five chapters: (1) introduction, (2) implementation, (3), performance of ASIC-based OTDR, (4) exploration in optical pre-amplification with a semiconductor optical amplifier, and

  10. Digital timing: sampling frequency, anti-aliasing filter and signal interpolation filter dependence on timing resolution

    International Nuclear Information System (INIS)

    Cho, Sanghee; Grazioso, Ron; Zhang Nan; Aykac, Mehmet; Schmand, Matthias

    2011-01-01

    The main focus of our study is to investigate how the performance of digital timing methods is affected by sampling rate, anti-aliasing and signal interpolation filters. We used the Nyquist sampling theorem to address some basic questions such as what will be the minimum sampling frequencies? How accurate will the signal interpolation be? How do we validate the timing measurements? The preferred sampling rate would be as low as possible, considering the high cost and power consumption of high-speed analog-to-digital converters. However, when the sampling rate is too low, due to the aliasing effect, some artifacts are produced in the timing resolution estimations; the shape of the timing profile is distorted and the FWHM values of the profile fluctuate as the source location changes. Anti-aliasing filters are required in this case to avoid the artifacts, but the timing is degraded as a result. When the sampling rate is marginally over the Nyquist rate, a proper signal interpolation is important. A sharp roll-off (higher order) filter is required to separate the baseband signal from its replicates to avoid the aliasing, but in return the computation will be higher. We demonstrated the analysis through a digital timing study using fast LSO scintillation crystals as used in time-of-flight PET scanners. From the study, we observed that there is no significant timing resolution degradation down to 1.3 Ghz sampling frequency, and the computation requirement for the signal interpolation is reasonably low. A so-called sliding test is proposed as a validation tool checking constant timing resolution behavior of a given timing pick-off method regardless of the source location change. Lastly, the performance comparison for several digital timing methods is also shown.

  11. Time resolution in scintillator based detectors for positron emission tomography

    International Nuclear Information System (INIS)

    Gundacker, S.

    2014-01-01

    In the domain of medical photon detectors L(Y)SO scintillators are used for positron emission tomography (PET). The interest for time of flight (TOF) in PET is increasing since measurements have shown that new crystals like L(Y)SO coupled to state of the art photodetectors, e.g. silicon photomultipliers (SiPM), can reach coincidence time resolutions (CTRs) of far below 500ps FWHM. To achieve these goals it is important to study the processe in the whole detection chain, i.e. the high energy particle or gamma interaction in the crystal, the scintillation process itself, the light propagation in the crystal with the light transfer to the photodetector, and the electronic readout. In this thesis time resolution measurements for a PET like system are performed in a coincidence setup utilizing the ultra fast amplifier discriminator NINO. We found that the time-over-threshold energy information provided by NINO shows a degradation in energy resolution for higher SiPM bias voltages. This is a consequence of the increasing dark count rate (DCR) of the SiPM with higher bias voltages together with the exponential decay of the signal. To overcome this problem and to operate the SiPM at its optimum voltage in terms of timing we developed a new electronic board that employs NINO only as a low noise leading edge discriminator together with an analog amplifier which delivers the energy information. With this new electronic board we indeed improved the measured CTR by about 15%. To study the limits of time resolution in more depth we measured the CTR with 2x2x3mm3 LSO:Ce codoped 0.4%Ca crystals coupled to commercially available SiPMs (Hamamatsu S10931-50P MPPC) and achieved a CTR of 108±5ps FWHM at an energy of 511keV. We determined the influence of the data acquisition system and the electronics on the CTR to be 27±2ps FWHM and thus negligible. To quantitatively understand the measured values, we developed a Monte Carlo simulation tool in MATLAB that incorporates the timing

  12. Effect of exposure time and image resolution on fractal dimension

    Energy Technology Data Exchange (ETDEWEB)

    An, Byung Mo; Heo, Min Suk; Lee, Seung Pyo; Lee, Sam Sun; Choi, Soon Chul; Park, Tae Won [College of Dentistry, Seoul National University, Seoul (Korea, Republic of); Kim, Jong Dae [Division of Information and Communication Engineering, Hallym University, Chuncheon (Korea, Republic of)

    2002-06-15

    To evaluate the effect of exposure time and image resolution on fractal dimension calculations for determining the optimal range of these two variances. Thirty-one radiographs of the mandibular angle area of sixteen human dry mandibles were taken at different exposure times (0.01, 0.08, 0.16, 0.25, 0.40, 0.64, and 0.80 s). Each radiograph was digitized at 1200 dpi, 8 bit, 256 gray level using a film scanner. We selected an Region of Interest (ROI) that corresponded to the same region as in each radiograph, but the resolution of ROI was degraded to 1000, 800, 600, 500, 400, 300, 200, and 100 dpi. The fractal dimension was calculated by using the tile-counting method for each image, and the calculated values were then compared statistically. As the exposure time and the image resolution increased, the mean value of the fractal dimension decreased, except the case where exposure time was set at 0.01 seconds (alpha = 0.05). The exposure time and image resolution affected the fractal dimension by interaction (p<0.001). When the exposure time was set to either 0.64 seconds or 0.80 seconds, the resulting fractal dimensions were lower, irrespective of image resolution, than at shorter exposure times (alpha = 0.05). The optimal range for exposure time and resolution was determined to be 0.08-0.40 seconds and from 400-1000 dpi, respectively. Adequate exposure time and image resolution is essential for acquiring the fractal dimension using tile-counting method for evaluation of the mandible.

  13. Effect of exposure time and image resolution on fractal dimension

    International Nuclear Information System (INIS)

    An, Byung Mo; Heo, Min Suk; Lee, Seung Pyo; Lee, Sam Sun; Choi, Soon Chul; Park, Tae Won; Kim, Jong Dae

    2002-01-01

    To evaluate the effect of exposure time and image resolution on fractal dimension calculations for determining the optimal range of these two variances. Thirty-one radiographs of the mandibular angle area of sixteen human dry mandibles were taken at different exposure times (0.01, 0.08, 0.16, 0.25, 0.40, 0.64, and 0.80 s). Each radiograph was digitized at 1200 dpi, 8 bit, 256 gray level using a film scanner. We selected an Region of Interest (ROI) that corresponded to the same region as in each radiograph, but the resolution of ROI was degraded to 1000, 800, 600, 500, 400, 300, 200, and 100 dpi. The fractal dimension was calculated by using the tile-counting method for each image, and the calculated values were then compared statistically. As the exposure time and the image resolution increased, the mean value of the fractal dimension decreased, except the case where exposure time was set at 0.01 seconds (alpha = 0.05). The exposure time and image resolution affected the fractal dimension by interaction (p<0.001). When the exposure time was set to either 0.64 seconds or 0.80 seconds, the resulting fractal dimensions were lower, irrespective of image resolution, than at shorter exposure times (alpha = 0.05). The optimal range for exposure time and resolution was determined to be 0.08-0.40 seconds and from 400-1000 dpi, respectively. Adequate exposure time and image resolution is essential for acquiring the fractal dimension using tile-counting method for evaluation of the mandible.

  14. Observation time and spontaneous resolution of primary phimosis in children

    Directory of Open Access Journals (Sweden)

    Pedro Luiz Toledo de Arruda Lourenção

    Full Text Available ABSTRACT Objective: to investigate spontaneous resolution rate of a series of patients with physiologic phimosis in relation to observation time and presence of symptoms. Methods: retrospective and longitudinal follow-up study of patients with physiologic phimosis, that did not apply topic treatment. These patients were invited for a new visit for reevaluation, or recent data were obtained by chart analysis. Spontaneous resolution rate was determined and statistically compared to age, presence of symptoms at first medical visit and time until reevaluation. Results: seventy one patients were included. Medium time of observation from first visit to reevaluation was 37.4 months. There was spontaneous resolution of phimosis in 32 (45% patients. Children with spontaneous resolution were younger at initial diagnosis and were observed during a longer period of time. Most asymptomatic patients at first visit presented spontaneous resolution. However, it was not possible to stablish a significant relationship between presence of symptoms and evolution of physiologic phimosis. Conclusions: time of observation was the main determinant of spontaneous resolution of patients with physiologic phimosis, reinforcing the current more conservative approach regarding circumcision of those patients.

  15. Precision cosmology with time delay lenses: high resolution imaging requirements

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Xiao-Lei; Liao, Kai [Department of Astronomy, Beijing Normal University, 19 Xinjiekouwai Street, Beijing, 100875 (China); Treu, Tommaso; Agnello, Adriano [Department of Physics, University of California, Broida Hall, Santa Barbara, CA 93106 (United States); Auger, Matthew W. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Marshall, Philip J., E-mail: xlmeng919@gmail.com, E-mail: tt@astro.ucla.edu, E-mail: aagnello@physics.ucsb.edu, E-mail: mauger@ast.cam.ac.uk, E-mail: liaokai@mail.bnu.edu.cn, E-mail: dr.phil.marshall@gmail.com [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, CA 94305 (United States)

    2015-09-01

    Lens time delays are a powerful probe of cosmology, provided that the gravitational potential of the main deflector can be modeled with sufficient precision. Recent work has shown that this can be achieved by detailed modeling of the host galaxies of lensed quasars, which appear as ''Einstein Rings'' in high resolution images. The distortion of these arcs and counter-arcs, as measured over a large number of pixels, provides tight constraints on the difference between the gravitational potential between the quasar image positions, and thus on cosmology in combination with the measured time delay. We carry out a systematic exploration of the high resolution imaging required to exploit the thousands of lensed quasars that will be discovered by current and upcoming surveys with the next decade. Specifically, we simulate realistic lens systems as imaged by the Hubble Space Telescope (HST), James Webb Space Telescope (JWST), and ground based adaptive optics images taken with Keck or the Thirty Meter Telescope (TMT). We compare the performance of these pointed observations with that of images taken by the Euclid (VIS), Wide-Field Infrared Survey Telescope (WFIRST) and Large Synoptic Survey Telescope (LSST) surveys. We use as our metric the precision with which the slope γ' of the total mass density profile ρ{sub tot}∝ r{sup −γ'} for the main deflector can be measured. Ideally, we require that the statistical error on γ' be less than 0.02, such that it is subdominant to other sources of random and systematic uncertainties. We find that survey data will likely have sufficient depth and resolution to meet the target only for the brighter gravitational lens systems, comparable to those discovered by the SDSS survey. For fainter systems, that will be discovered by current and future surveys, targeted follow-up will be required. However, the exposure time required with upcoming facilitites such as JWST, the Keck Next Generation

  16. Precision cosmology with time delay lenses: High resolution imaging requirements

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Xiao -Lei [Beijing Normal Univ., Beijing (China); Univ. of California, Santa Barbara, CA (United States); Treu, Tommaso [Univ. of California, Santa Barbara, CA (United States); Univ. of California, Los Angeles, CA (United States); Agnello, Adriano [Univ. of California, Santa Barbara, CA (United States); Univ. of California, Los Angeles, CA (United States); Auger, Matthew W. [Univ. of Cambridge, Cambridge (United Kingdom); Liao, Kai [Beijing Normal Univ., Beijing (China); Univ. of California, Santa Barbara, CA (United States); Univ. of California, Los Angeles, CA (United States); Marshall, Philip J. [Stanford Univ., Stanford, CA (United States)

    2015-09-28

    Lens time delays are a powerful probe of cosmology, provided that the gravitational potential of the main deflector can be modeled with sufficient precision. Recent work has shown that this can be achieved by detailed modeling of the host galaxies of lensed quasars, which appear as ``Einstein Rings'' in high resolution images. The distortion of these arcs and counter-arcs, as measured over a large number of pixels, provides tight constraints on the difference between the gravitational potential between the quasar image positions, and thus on cosmology in combination with the measured time delay. We carry out a systematic exploration of the high resolution imaging required to exploit the thousands of lensed quasars that will be discovered by current and upcoming surveys with the next decade. Specifically, we simulate realistic lens systems as imaged by the Hubble Space Telescope (HST), James Webb Space Telescope (JWST), and ground based adaptive optics images taken with Keck or the Thirty Meter Telescope (TMT). We compare the performance of these pointed observations with that of images taken by the Euclid (VIS), Wide-Field Infrared Survey Telescope (WFIRST) and Large Synoptic Survey Telescope (LSST) surveys. We use as our metric the precision with which the slope γ' of the total mass density profile ρtot∝ r–γ' for the main deflector can be measured. Ideally, we require that the statistical error on γ' be less than 0.02, such that it is subdominant to other sources of random and systematic uncertainties. We find that survey data will likely have sufficient depth and resolution to meet the target only for the brighter gravitational lens systems, comparable to those discovered by the SDSS survey. For fainter systems, that will be discovered by current and future surveys, targeted follow-up will be required. Furthermore, the exposure time required with upcoming facilitites such as JWST, the Keck Next Generation Adaptive

  17. The timing resolution of scintillation-detector systems: Monte Carlo analysis

    International Nuclear Information System (INIS)

    Choong, Woon-Seng

    2009-01-01

    Recent advancements in fast scintillating materials and fast photomultiplier tubes (PMTs) have stimulated renewed interest in time-of-flight (TOF) positron emission tomography (PET). It is well known that the improvement in the timing resolution in PET can significantly reduce the noise variance in the reconstructed image resulting in improved image quality. In order to evaluate the timing performance of scintillation detectors used in TOF PET, we use Monte Carlo analysis to model the physical processes (crystal geometry, crystal surface finish, scintillator rise time, scintillator decay time, photoelectron yield, PMT transit time spread, PMT single-electron response, amplifier response and time pick-off method) that can contribute to the timing resolution of scintillation-detector systems. In the Monte Carlo analysis, the photoelectron emissions are modeled by a rate function, which is used to generate the photoelectron time points. The rate function, which is simulated using Geant4, represents the combined intrinsic light emissions of the scintillator and the subsequent light transport through the crystal. The PMT output signal is determined by the superposition of the PMT single-electron response resulting from the photoelectron emissions. The transit time spread and the single-electron gain variation of the PMT are modeled in the analysis. Three practical time pick-off methods are considered in the analysis. Statistically, the best timing resolution is achieved with the first photoelectron timing. The calculated timing resolution suggests that a leading edge discriminator gives better timing performance than a constant fraction discriminator and produces comparable results when a two-threshold or three-threshold discriminator is used. For a typical PMT, the effect of detector noise on the timing resolution is negligible. The calculated timing resolution is found to improve with increasing mean photoelectron yield, decreasing scintillator decay time and

  18. High spatial and time resolutions with gas ionization detectors

    International Nuclear Information System (INIS)

    Pouthas, J.

    2001-09-01

    This document presents the principles and the characteristics of the gaseous ionisation detectors used in position and timing measurements. The first two parts recall the main notions (electron and ion motions, gaseous amplification, signal formation) and their applications to the proportional counter and the wire chamber. The explanation of the signal formation makes use of the Ramo theorem. The third part is devoted to the different types of wire chambers: drift or cathode strip chambers, TPC (time projection chamber). Some aspects on construction and ageing are also presented. Part 4 is on the detectors in which the multiplication is performed by a 'Parallel Plate' system (PPAC, Pestov counter). Special attention is paid to the RPCs (Resistive Plate Chambers) and their timing resolutions. Part 5 concentrates on 'Micro-pattern detectors' which use different kinds of microstructure for gaseous amplification. The new detectors MICROMEGAS, CAT (compteur a trous) and GEM (gas electron multiplier) and some of their applications are presented. The last part is a bibliography including some comments on the documents. (author)

  19. Correction of time resolution of an ambulatory cardiac monitor (VEST)

    International Nuclear Information System (INIS)

    Kumita, Shin-ichiro; Nishimura, Tsunehiko; Hayashida, Kohei; Uehara, Toshiisa

    1990-01-01

    Using ambulatory cardiac monitor (VEST) at exercise study, its time resolution is very important factor. We evaluated the time resolution of VEST using pulsate cardiac baloon phantom. Four analysis were carried out; no smoothing (NS) method, 3 points smoothing (3S) method, short sampling interval (SS) method, and digital filter (DF) method. By comparison of |ΔEF| (|EF:HR120-EF: HR60|) among 4 analysis methods, |ΔEF| by DF method was significant small (NS:3.58±3.01, 3S: 4.46±0.95, SS: 3.35±3.26, DF: 1.11±1.28%). We conclude that correction of time resolution by digital filter is necessary when we use VEST during exercise. (author)

  20. Visualization of Time-Varying Weather Ensembles across Multiple Resolutions.

    Science.gov (United States)

    Biswas, Ayan; Lin, Guang; Liu, Xiaotong; Shen, Han-Wei

    2017-01-01

    Uncertainty quantification in climate ensembles is an important topic for the domain scientists, especially for decision making in the real-world scenarios. With powerful computers, simulations now produce time-varying and multi-resolution ensemble data sets. It is of extreme importance to understand the model sensitivity given the input parameters such that more computation power can be allocated to the parameters with higher influence on the output. Also, when ensemble data is produced at different resolutions, understanding the accuracy of different resolutions helps the total time required to produce a desired quality solution with improved storage and computation cost. In this work, we propose to tackle these non-trivial problems on the Weather Research and Forecasting (WRF) model output. We employ a moment independent sensitivity measure to quantify and analyze parameter sensitivity across spatial regions and time domain. A comparison of clustering structures across three resolutions enables the users to investigate the sensitivity variation over the spatial regions of the five input parameters. The temporal trend in the sensitivity values is explored via an MDS view linked with a line chart for interactive brushing. The spatial and temporal views are connected to provide a full exploration system for complete spatio-temporal sensitivity analysis. To analyze the accuracy across varying resolutions, we formulate a Bayesian approach to identify which regions are better predicted at which resolutions compared to the observed precipitation. This information is aggregated over the time domain and finally encoded in an output image through a custom color map that guides the domain experts towards an adaptive grid implementation given a cost model. Users can select and further analyze the spatial and temporal error patterns for multi-resolution accuracy analysis via brushing and linking on the produced image. In this work, we collaborate with a domain expert whose

  1. High-resolution seismic wave propagation using local time stepping

    KAUST Repository

    Peter, Daniel

    2017-03-13

    High-resolution seismic wave simulations often require local refinements in numerical meshes to accurately capture e.g. steep topography or complex fault geometry. Together with explicit time schemes, this dramatically reduces the global time step size for ground-motion simulations due to numerical stability conditions. To alleviate this problem, local time stepping (LTS) algorithms allow an explicit time stepping scheme to adapt the time step to the element size, allowing nearoptimal time steps everywhere in the mesh. This can potentially lead to significantly faster simulation runtimes.

  2. [Performance of normal young adults in two temporal resolution tests].

    Science.gov (United States)

    Zaidan, Elena; Garcia, Adriana Pontin; Tedesco, Maria Lucy Fraga; Baran, Jane A

    2008-01-01

    temporal auditory processing is defined as the perception of sound or of sound alteration within a restricted time interval and is considered a fundamental ability for the auditory perception of verbal and non verbal sounds, for the perception of music, rhythm, periodicity and in the discrimination of pitch, duration and of phonemes. to compare the performance of normal Brazilian adults in two temporal resolution tests: the Gaps-in-Noise Test (GIN) and the Random Gap Detection Test (RGDT), and to analyze potential differences of performance in these two tests. twenty-five college students with normal hearing (11 males and 14 females) and no history of educational, neurological and/or language problems, underwent the GIN and RGDT at 40dB SL. statistically significant gender effects for both tests were found, with female participants showing poorer performance on both temporal processing tests. In addition, a comparative analysis of the results obtained in the GIN and RGDT revealed significant differences in the threshold measures derived for these two tests. In general, significantly better gap detection thresholds were observed for both male and female participants on the GIN test when compared to the results obtained for the RGDT. male participants presented better performances on both RGDT and GIN, when compared to the females. There were no differences in performance between right and left ears on the GIN test. Participants of the present investigation, males and females, performed better on the GIN when compared to the RGDT. The GIN presented advantages over the RGDT, not only in terms of clinical validity and sensibility, but also in terms of application and scoring.

  3. Super-High Resolution Time Interval Measurement Method Based on Time-Space Relationships

    International Nuclear Information System (INIS)

    Bao-Qiang, Du; Wei, Zhou

    2009-01-01

    Based on the principle of quantized delay-time, a super-high resolution time interval measurement method is proposed based on time-space relationships. Using the delay-time stability that time and frequency signal travel in a specific medium, the measured time interval can be quantized. Combined with the phase coincidence detection technique, the measurement of time can be changed into the measurement of space length. The resolution and the stability of the measurement system are easily improved. Experimental results show that the measurement resolution of the measured time interval depends on the length difference of the double delay-time unit. When the length difference is set up on millimeter level or sub-millimeter level, super-high measurement resolution from hundreds of picosecond to tens of picosecond can be obtained

  4. Measurement of time resolution of thermoregulated SiPM for time of flight detectors

    Energy Technology Data Exchange (ETDEWEB)

    Cavazza, D.; D' Antone, I.; Foschi, E.; Guandalini, C.; Lax, I.; Levi, G.; Quadrani, L. [Department of Physics and INFN, Viale B. Pichat 4/2, 40127 Bologna (Italy); Sbarra, C., E-mail: cristina.sbarra@bo.infn.it [INFN of Padova, Via Marzolo 8, 35131 Padova (Italy); Zuffa, M. [Department of Physics and INFN, Viale B. Pichat 4/2, 40127 Bologna (Italy)

    2012-11-11

    Silicon Photomultipliers (SiPM) are considered very promising in many application where high timing performances, low cost, hardness to radiation damage and single photon counting are requested. Such applications go from astrophysics, high energy accelerator physics to medical physics. A group of SiPM from Hamamatsu has been tested with a low noise fast amplifier based on a hetero-junction FET, mounted on a proper front end board. A first telescope prototype has been used to test the electronics and results are shown. The SiPM time resolution has been measured to be {sigma}{approx}30 ps, in agreement with other studies reported in literature. The SiPM gain depends critically on temperature and a thermoelectric module to control the circuit was also studied in order to use the system for space detectors.

  5. Performance Evaluations for Super-Resolution Mosaicing on UAS Surveillance Videos

    Directory of Open Access Journals (Sweden)

    Aldo Camargo

    2013-05-01

    Full Text Available Abstract Unmanned Aircraft Systems (UAS have been widely applied for reconnaissance and surveillance by exploiting information collected from the digital imaging payload. The super-resolution (SR mosaicing of low-resolution (LR UAS surveillance video frames has become a critical requirement for UAS video processing and is important for further effective image understanding. In this paper we develop a novel super-resolution framework, which does not require the construction of sparse matrices. The proposed method implements image operations in the spatial domain and applies an iterated back-projection to construct super-resolution mosaics from the overlapping UAS surveillance video frames. The Steepest Descent method, the Conjugate Gradient method and the Levenberg-Marquardt algorithm are used to numerically solve the nonlinear optimization problem for estimating a super-resolution mosaic. A quantitative performance comparison in terms of computation time and visual quality of the super-resolution mosaics through the three numerical techniques is presented.

  6. Breaking time-resolution limits in pulse radiolysis

    International Nuclear Information System (INIS)

    Yang Jinfeng; Kondoh, Takafumi; Norizawa, Kimihiro; Yoshida, Yoichi; Tagawa, Seiichi

    2009-01-01

    Pulse radiolysis, which is a time-resolved stroboscopic method based on ultrashort electron pulse and ultrashort analyzing light, is widely used for the study of the chemical kinetics and radiation primary processes or reactions. Although it has become possible to use femtosecond-pulse electron beam and femtosecond laser light in pulse radiolysis, the resolution is limited by the difference in group velocities of the electrons and the light in sample. In this contribution, we introduce a concept of equivalent velocity spectroscopy (EVS) into pulse radiolysis and demonstrate the methodology experimentally. In EVS, both the electron and the analyzing light pulses precisely overlap at every point in the sample and throughout the propagation time by rotating the electron pulse. The advance allows us to overcome the resolution degradation due to the different group velocity. We also present a method for measuring the rotated angle of the electron pulse and a technique for rotating the electron pulse with a deflecting cavity.

  7. Can Transient Phenomena Help Improving Time Resolution in Scintillators?

    CERN Document Server

    Lecoq, P; Vasiliev, A

    2014-01-01

    The time resolution of a scintillator-based detector is directly driven by the density of photoelectrons generated in the photodetector at the detection threshold. At the scintillator level it is related to the intrinsic light yield, the pulse shape (rise time and decay time) and the light transport from the gamma-ray conversion point to the photodetector. When aiming at 10 ps time resolution, fluctuations in the thermalization and relaxation time of hot electrons and holes generated by the interaction of ionization radiation with the crystal become important. These processes last for up to a few tens of ps and are followed by a complex trapping-detrapping process, Poole-Frenkel effect, Auger ionization of traps and electron-hole recombination, which can last for a few ns with very large fluctuations. This paper will review the different processes at work and evaluate if some of the transient phenomena taking place during the fast thermalization phase can be exploited to extract a time tag with a precision in...

  8. Time resolution improvement of Schottky CdTe PET detectors using digital signal processing

    International Nuclear Information System (INIS)

    Nakhostin, M.; Ishii, K.; Kikuchi, Y.; Matsuyama, S.; Yamazaki, H.; Torshabi, A. Esmaili

    2009-01-01

    We present the results of our study on the timing performance of Schottky CdTe PET detectors using the technique of digital signal processing. The coincidence signals between a CdTe detector (15x15x1 mm 3 ) and a fast liquid scintillator detector were digitized by a fast digital oscilloscope and analyzed. In the analysis, digital versions of the elements of timing circuits, including pulse shaper and time discriminator, were created and a digital implementation of the Amplitude and Rise-time Compensation (ARC) mode of timing was performed. Owing to a very fine adjustment of the parameters of timing measurement, a good time resolution of less than 9.9 ns (FWHM) at an energy threshold of 150 keV was achieved. In the next step, a new method of time pickoff for improvement of timing resolution without loss in the detection efficiency of CdTe detectors was examined. In the method, signals from a CdTe detector are grouped by their rise-times and different procedures of time pickoff are applied to the signals of each group. Then, the time pickoffs are synchronized by compensating the fixed time offset, caused by the different time pickoff procedures. This method leads to an improved time resolution of ∼7.2 ns (FWHM) at an energy threshold of as low as 150 keV. The methods presented in this work are computationally fast enough to be used for online processing of data in an actual PET system.

  9. Time and Frequency Localized Pulse Shape for Resolution Enhancement in STFT-BOTDR

    Directory of Open Access Journals (Sweden)

    Linqing Luo

    2016-01-01

    Full Text Available Short-Time Fourier Transform-Brillouin Optical Time-Domain Reflectometry (STFT-BOTDR implements STFT over the full frequency spectrum to measure the distributed temperature and strain along the optic fiber, providing new research advances in dynamic distributed sensing. The spatial and frequency resolution of the dynamic sensing are limited by the Signal to Noise Ratio (SNR and the Time-Frequency (T-F localization of the input pulse shape. T-F localization is fundamentally important for the communication system, which suppresses interchannel interference (ICI and intersymbol interference (ISI to improve the transmission quality in multicarrier modulation (MCM. This paper demonstrates that the T-F localized input pulse shape can enhance the SNR and the spatial and frequency resolution in STFT-BOTDR. Simulation and experiments of T-F localized different pulses shapes are conducted to compare the limitation of the system resolution. The result indicates that rectangular pulse should be selected to optimize the spatial resolution and Lorentzian pulse could be chosen to optimize the frequency resolution, while Gaussian shape pulse can be used in general applications for its balanced performance in both spatial and frequency resolution. Meanwhile, T-F localization is proved to be useful in the pulse shape selection for system resolution optimization.

  10. Effect produced by the charge collection time upon the time and energy resolution of semiconductor detectors

    International Nuclear Information System (INIS)

    Morozov, V.A.; Stegailov, V.I.; Zinov, V.G.; Yashin, S.N.

    1986-01-01

    The effect produced by the charge collection time upon the time and energy resolution of semiconductor detectors has been studied. It is shown that sampling of pulse rise times permits one to identify in coaxial detectors a group of pulses corresponding to the detection of radiation in surface layers of the detector. Choosing pulses with the maximum rise time rate allows one to improve the time resolution of the coincidence sepectrometer and achieve 2tau=1.65 ns, instead of the 2tau=5.50 ns for coincidences of the 1332 keV gamma line and β - particles from 60 Co. (orig.)

  11. Time Reconstruction and Performance of the CMS Electromagnetic Calorimeter

    CERN Document Server

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Gomez Ceballos, G; Hahn, K A; Harris, P; Jaditz, S; Kim, Y; Klute, M; Lee, Y J; Li, W; Loizides, C; Ma, T; Miller, M; Nahn, S; Paus, C; Roland, C; Roland, G; Rudolph, M; Stephans, G; Sumorok, K; Sung, K; Vaurynovich, S; Wenger, E A; Wyslouch, B; Xie, S; Yilmaz, Y; Yoon, A S; Bailleux, D; Cooper, S I; Cushman, P; Dahmes, B; De Benedetti, A; Dolgopolov, A; Dudero, P R; Egeland, R; Franzoni, G; Haupt, J; Inyakin, A; Klapoetke, K; Kubota, Y; Mans, J; Mirman, N; Petyt, D; Rekovic, V; Rusack, R; Schroeder, M; Singovsky, A; Zhang, J; Cremaldi, L M; Godang, R; Kroeger, R; Perera, L; Rahmat, R; Sanders, D A; Sonnek, P; Summers, D; Bloom, K; Bockelman, B; Bose, S; Butt, J; Claes, D R; Dominguez, A; Eads, M; Keller, J; Kelly, T; Kravchenko, I; Lazo-Flores, J; Lundstedt, C; Malbouisson, H; Malik, S; Snow, G R; Baur, U; Iashvili, I; Kharchilava, A; Kumar, A; Smith, K; Strang, M; Alverson, G; Barberis, E; Boeriu, O; Eulisse, G; Govi, G; McCauley, T; Musienko, Y; Muzaffar, S; Osborne, I; Paul, T; Reucroft, S; Swain, J; Taylor, L; Tuura, L; Anastassov, A; Gobbi, B; Kubik, A; Ofierzynski, R A; Pozdnyakov, A; Schmitt, M; Stoynev, S; Velasco, M; Won, S; Antonelli, L; Berry, D; Hildreth, M; Jessop, C; Karmgard, D J; Kolberg, T; Lannon, K; Lynch, S; Marinelli, N; Morse, D M; Ruchti, R; Slaunwhite, J; Warchol, J; Wayne, M; Bylsma, B; Durkin, L S; Gilmore, J; Gu, J; Killewald, P; Ling, T Y; Williams, G; Adam, N; Berry, E; Elmer, P; Garmash, A; Gerbaudo, D; Halyo, V; Hunt, A; Jones, J; Laird, E; Marlow, D; Medvedeva, T; Mooney, M; Olsen, J; Piroué, P; Stickland, D; Tully, C; Werner, J S; Wildish, T; Xie, Z; Zuranski, A; Acosta, J G; Bonnett Del Alamo, M; Huang, X T; Lopez, A; Mendez, H; Oliveros, S; Ramirez Vargas, J E; Santacruz, N; Zatzerklyany, A; Alagoz, E; Antillon, E; Barnes, V E; Bolla, G; Bortoletto, D; Everett, A; Garfinkel, A F; Gecse, Z; Gutay, L; Ippolito, N; Jones, M; Koybasi, O; Laasanen, A T; Leonardo, N; Liu, C; Maroussov, V; Merkel, P; Miller, D H; Neumeister, N; Sedov, A; Shipsey, I; Yoo, H D; Zheng, Y; Jindal, P; Parashar, N; Cuplov, V; Ecklund, K M; Geurts, F J M; Liu, J H; Maronde, D; Matveev, M; Padley, B P; Redjimi, R; Roberts, J; Sabbatini, L; Tumanov, A; Betchart, B; Bodek, A; Budd, H; Chung, Y S; de Barbaro, P; Demina, R; Flacher, H; Gotra, Y; Harel, A; Korjenevski, S; Miner, D C; Orbaker, D; Petrillo, G; Vishnevskiy, D; Zielinski, M; Bhatti, A; Demortier, L; Goulianos, K; Hatakeyama, K; Lungu, G; Mesropian, C; Yan, M; Atramentov, O; Bartz, E; Gershtein, Y; Halkiadakis, E; Hits, D; Lath, A; Rose, K; Schnetzer, S; Somalwar, S; Stone, R; Thomas, S; Watts, T L; Cerizza, G; Hollingsworth, M; Spanier, S; Yang, Z C; York, A; Asaadi, J; Aurisano, A; Eusebi, R; Golyash, A; Gurrola, A; Kamon, T; Nguyen, C N; Pivarski, J; Safonov, A; Sengupta, S; Toback, D; Weinberger, M; Akchurin, N; Berntzon, L; Gumus, K; Jeong, C; Kim, H; Lee, S W; Popescu, S; Roh, Y; Sill, A; Volobouev, I; Washington, E; Wigmans, R; Yazgan, E; Engh, D; Florez, C; Johns, W; Pathak, S; Sheldon, P; Andelin, D; Arenton, M W; Balazs, M; Boutle, S; Buehler, M; Conetti, S; Cox, B; Hirosky, R; Ledovskoy, A; Neu, C; Phillips II, D; Ronquest, M; Yohay, R; Gollapinni, S; Gunthoti, K; Harr, R; Karchin, P E; Mattson, M; Sakharov, A; Anderson, M; Bachtis, M; Bellinger, J N; Carlsmith, D; Crotty, I; Dasu, S; Dutta, S; Efron, J; Feyzi, F; Flood, K; Gray, L; Grogg, K S; Grothe, M; Hall-Wilton, R; Jaworski, M; Klabbers, P; Klukas, J; Lanaro, A; Lazaridis, C; Leonard, J; Loveless, R; Magrans de Abril, M; Mohapatra, A; Ott, G; Polese, G; Reeder, D; Savin, A; Smith, W H; Sourkov, A; Swanson, J; Weinberg, M; Wenman, D; Wensveen, M; White, A

    2010-01-01

    The resolution and the linearity of time measurements made with the CMS electromagnetic calorimeter are studied with samples of data from test beam electrons, cosmic rays, and beam-produced muons. The resulting time resolution measured by lead tungstate crystals is better than 100 ps for energy deposits larger than 10 GeV. Crystal-to-crystal synchronization with a precision of 500 ps is performed using muons produced with the first LHC beams in 2008.

  12. Subpicosecond time-resolution image converter the picochron

    International Nuclear Information System (INIS)

    Butslov, M.M.; Fanchenko, S.D.; Chikin, R.V.

    The problem of X-band resonance ultra-high-speed electron image swept in image converters is considered. A time analysis image converter tube is described. It is provided with a circular image-sweeping system, the sweeping speed ranging from 1 up to 2 light velocities. The swept-image intensifier makes it possible to record every electron emerging from the input photocathode. The time analysis electrostatic lens provides an electronic field at the input photocathode, strong enough to obtain a high physical time resolution. The image sweeping system to be described enables one to have a 5.10 -13 s time resolution over on observation period as long as 5.10 -8 s. It requires no precise limiting with the process to observed. The picochron tube design is described together with some results of its testing in Nd-laser experiments. Transitories as short as 0.5-1psec have been detected in ultra-short laser radiation pulses

  13. Femtosecond Resolution Timing in Multi-GS/s Waveform Digitizing ASICs

    Science.gov (United States)

    Orel, Peter; Varner, Gary S.

    2017-07-01

    A waveform digitizer with high-resolution timing provides with the possibility of a novel approach to vertex detectors for high-luminosity particle colliders. Present efforts are centered on the development of an application specific integrated circuit (ASIC) intended to measure signal arrival times with timing resolution in the range of 100 fs or less. The design of such an ASIC requires very good understanding of the effects that impact the timing resolution. This paper presents the simulation results that clearly identify and quantify the sources of error and the underlying coupling mechanisms. In addition, a synthetic waveform generator, developed solely for this purpose, is presented and validated through the measurement results. Crucial knowledge, insights, and confidence have been gained for the development of the ASIC or any other fast, wideband RF systems that aim to achieve such performance.

  14. Time lens for high-resolution neutron time-of-flight spectrometers

    International Nuclear Information System (INIS)

    Baumann, K.; Gaehler, R.; Grigoriev, P.; Kats, E.I.

    2005-01-01

    We examine in analytic and numeric ways the imaging effects of temporal neutron lenses created by traveling magnetic fields. For fields of parabolic shape we derive the imaging equations, investigate the time magnification, the evolution of the phase-space element, the gain factor, and the effect of finite beam size. The main aberration effects are calculated numerically. The system is technologically feasible and should convert neutron time-of-flight instruments from pinhole to imaging configuration in time, thus enhancing intensity and/or time resolution. Further fields of application for high-resolution spectrometry may be opened

  15. How Photonic Crystals Can Improve the Timing Resolution of Scintillators

    CERN Document Server

    Lecoq, P; Knapitsch, A

    2013-01-01

    Photonic crystals (PhCs) and quantum optics phenomena open interesting perspectives to enhance the light extraction from scintillating me dia with high refractive indices as demonstrated by our previous work. By doing so, they also in fl uence the timing resolution of scintillators by improving the photostatistics. The present cont ribution will demonstrate that they are actually doing much more. Indeed, photonic crystals, if properly designed, allow the extr action of fast light propagation modes in the crystal with higher efficiency, therefore contributing to increasing the density of photons in the early phase of the light pulse. This is of particular interest to tag events at future high-energy physics colliders, such as CLIC, with a bunch-crossing rate of 2 GHz, as well as for a new generation of time-of-flight positron emission tomographs (TOFPET) aiming at a coincidence timing resolution of 100 ps FWHM. At this level of precision, good control of the light propagation modes is crucial if we consid...

  16. Test beam & time resolution analysis for UFSD and CVD diamond detectors

    CERN Document Server

    Scali, Stefano

    2017-01-01

    The ever-increasing luminosity in particle physics, aimed at seeking new phenomena, has led to the need for radiation-hard detectors with a remarkable time resolution. To reach the goal several tests and data analysis has been performed but further development is still required. During my internship I have participated to the test of new sensors. After an introduction to the theoretical framework this report describes the data taking procedure using SPS beam at the H8 site in Prevessin. The second part describes the data analysis and extrapolation of the time resolution for many boards.

  17. Measurements of timing resolution of ultra-fast silicon detectors with the SAMPIC WTDC

    CERN Document Server

    Breton, Dominique

    2016-11-01

    The SAMpler for PICosecond time (SAMPIC) chip has been designed by a collaboration including CEA/IRFU/SEDI, Saclay and CNRS/LAL/SERDI, Orsay. It benefits from both the quick response of a time to digital converter (TDC) and the versatility of a waveform digitizer to perform accurate timing measurements. Thanks to the sampled signals, smart algorithms making best use of the pulse shape can be used to maximize time resolution. A software framework has been developed to analyse the SAMPIC output data and extract timing information by using either a constant fraction discriminator or a fast cross-correlation algorithm. SAMPIC timing capabilities together with the software framework have been tested using Gaussian signals generated by a signal generator or by silicon detectors pulsed with an infra-red laser. Under these ideal experimental conditions, the SAMPIC chip has proven to be capable of timing resolutions down to 4 (40) ps with synthesized (silicon detector) signals.

  18. Measurement of Time Resolution of the Mu2e LYSO Calorimeter Prototype

    Energy Technology Data Exchange (ETDEWEB)

    Atanov, N. [Jouint Inst. of Nuclear Research, Dubna (Russia); et al.

    2015-09-16

    In this paper we present the time resolution measurements of the LutetiumYttrium Oxyorthosilicate (LYSO) calorimeter prototype for the Mu2e experiment. The measurements have been performed using the e- beam of the Beam Test Facility (BTF) in Frascati, Italy in the energy range from 100 to 400 MeV. The calorimeter prototype consisted of twenty five 30x30x130 mm3, LYSO crystals read out by 10x10 mm2 Hamamatsu Avalanche Photodiodes (APDs). The energy dependence of the measured time resolution can be parametrized as σt(E) = a/pE/GeV⊕b, with the stochastic and constant terms a = (51±1) ps and b = (14 ± 1) ps, respectively. This corresponds to the time resolution of (162 ± 3) ps at 100 MeV.

  19. Motor preparation is modulated by the resolution of the response timing information.

    Science.gov (United States)

    Carlsen, Anthony N; Mackinnon, Colum D

    2010-03-31

    In the present experiment, the temporal predictability of response time was systematically manipulated to examine its effect on the time course of motor pre-programming and release of the intended movement by an acoustic startle stimulus. Participants performed a ballistic right wrist extension task in four different temporal conditions: 1) a variable foreperiod simple RT task, 2) a fixed foreperiod simple RT task, 3) a low resolution countdown anticipation-timing task, and 4) a high resolution anticipation-timing task. For each task, a startling acoustic stimulus (124dB) was presented at several intervals prior to the "go" signal ("go" -150ms, -500ms, and -1500ms). Results from the startle trials showed that the time course of movement pre-programming was affected by the temporal uncertainty of the imperative "go" cue. These findings demonstrate that the resolution of the timing information regarding the response cue has a marked effect on the timing of movement preparation such that under conditions of low temporal resolution, participants plan the movement well in advance in accordance with the anticipated probability of onset of the cue, whereas movement preparation is delayed until less than 500ms prior to response time when continuous temporal information is provided. Copyright 2010 Elsevier B.V. All rights reserved.

  20. Resolution studies and performance evaluation of the LHCb VELO upgrade

    CERN Document Server

    Hynds, Daniel Peter McFarlane; Soler, Paul; Parkes, Christopher

    2015-03-25

    The LHCb detector at CERN is scheduled to undergo an upgrade during the second long shutdown of the LHC. As part of this upgrade, the vertex detector (VELO) will be replaced with a new hybrid pixel detector, based on an evolution of the Timepix ASIC. The performance of this detector should improve upon that achieved by the current VELO, in addition to facilitating the complete detector readout at 40 MHz. As part of the preparation for this upgrade, this thesis presents the results of studies carried out on the single hit resolution of silicon hybrid pixel detectors. The development of a particle beam telescope has been carried out to allow these studies, shown to operate with track rates in excess of 45 kHz and with a pointing resolution at the device under test of less than 2 μm. A wide range of sensor types, thicknesses and resistivities have then been tested under different operating conditions and the results presented, with single hit resolutions varying between 4 μm and 12 μm depending on the conditi...

  1. A flexible multi-channel high-resolution time-to-digital converter ASIC

    CERN Document Server

    Mota, M; Debieux, S; Ryzhov, V; Moreira, P; Marchioro, A

    2000-01-01

    A data driven multi-channel Time-to-Digital Converter (TDC) circuit with programmable resolution ( similar to 25ps - 8OOps binning) and a dynamic range of 102.4mus has been implemented in a 0.25mum CMOS technology. An on-chip PLL is used for clock multiplication up to 320MHz from an external 40MHz reference. A 32 element Delay Locked Loop (DLL) performs time interpolation down to 97.5ps. Finally, finer time interpolation is obtained using four samples of the DLL separated by 24.5ps generated by an adjustable on-chip RC delay line. In the lower resolution modes of operation, 32 TDC channels are available. In the highest resolution mode eight channels are available, since four low-resolution channels are used to perform a single fine time interpolation. The TDC is capable of measuring both leading and trailing edges of the input signal. Measurements are initially stored as time stamps in individual four-location deep asynchronous channel buffers. After proper encoding, measurements are written into four 256-dee...

  2. High-resolution (noble) gas time series for aquatic research

    Science.gov (United States)

    Popp, A. L.; Brennwald, M. S.; Weber, U.; Kipfer, R.

    2017-12-01

    We developed a portable mass spectrometer (miniRUEDI) for on-site quantification of gas concentrations (He, Ar, Kr, N2, O2, CO2, CH4, etc.) in terrestrial gases [1,2]. Using the gas-equilibrium membrane-inlet technique (GE-MIMS), the miniRUEDI for the first time also allows accurate on-site and long-term dissolved-gas analysis in water bodies. The miniRUEDI is designed for operation in the field and at remote locations, using battery power and ambient air as a calibration gas. In contrast to conventional sampling and subsequent lab analysis, the miniRUEDI provides real-time and continuous time series of gas concentrations with a time resolution of a few seconds.Such high-resolution time series and immediate data availability open up new opportunities for research in highly dynamic and heterogeneous environmental systems. In addition the combined analysis of inert and reactive gas species provides direct information on the linkages of physical and biogoechemical processes, such as the air/water gas exchange, excess air formation, O2 turnover, or N2 production by denitrification [1,3,4].We present the miniRUEDI instrument and discuss its use for environmental research based on recent applications of tracking gas dynamics related to rapid and short-term processes in aquatic systems. [1] Brennwald, M.S., Schmidt, M., Oser, J., and Kipfer, R. (2016). Environmental Science and Technology, 50(24):13455-13463, doi: 10.1021/acs.est.6b03669[2] Gasometrix GmbH, gasometrix.com[3] Mächler, L., Peter, S., Brennwald, M.S., and Kipfer, R. (2013). Excess air formation as a mechanism for delivering oxygen to groundwater. Water Resources Research, doi:10.1002/wrcr.20547[4] Mächler, L., Brennwald, M.S., and Kipfer, R. (2013). Argon Concentration Time-Series As a Tool to Study Gas Dynamics in the Hyporheic Zone. Environmental Science and Technology, doi: 10.1021/es305309b

  3. Sub-picosecond Resolution Time-to-Digital Converter

    Energy Technology Data Exchange (ETDEWEB)

    Bratov, Vladimir [Advanced Science and Novel Technology Company, Rancho Palos Verdes, CA (United States); Katzman, Vladimir [Advanced Science and Novel Technology Company, Rancho Palos Verdes, CA (United States); Binkley, Jeb [Advanced Science and Novel Technology Company, Rancho Palos Verdes, CA (United States)

    2006-03-30

    Time-to-digital converters with sub-picosecond resolutions are needed to satisfy the requirements of time-on-flight measurements of the next generation of high energy and nuclear physics experiments. The converters must be highly integrated, power effective, low cost, and feature plug-and-play capabilities to handle the increasing number of channels (up to hundreds of millions) in future Department of Energy experiments. Current state-off-the-art time-to-digital converter integrated circuits do not have the sufficient degree of integration and flexibility to fulfill all the described requirements. During Phase I, the Advanced Science and Novel Technology Company in cooperation with the nuclear physics division of the Oak Ridge National Laboratory has developed the architecture of a novel time-to-digital converter with multiple channels connected to an external processor through a special interfacing block and synchronized by clock signals generated by an internal phase-locked loop. The critical blocks of the system including signal delay lines and delay-locked loops with proprietary differential delay cells, as well as the required digital code converter and the clock period counter have been designed and simulated using the advanced SiGe120 BiCMOS technological process. The results of investigations demonstrate a possibility to achieve the digitization accuracy within 1ps. ADSANTEC has demonstrated the feasibility of the proposed concept in computer simulations. The proposed system will be a critical component for the next generation of NEP experiments.

  4. Measuring the electron bunch timing with femtosecond resolution at FLASH

    International Nuclear Information System (INIS)

    Bock, Marie Kristin

    2013-03-01

    Bunch arrival time monitors (BAMs) are an integral part of the laser-based synchronisation system which is being developed at the Free Electron Laser in Hamburg (FLASH).The operation principle comprises the measurement of the electron bunch arrival time relative to the optical timing reference, which is provided by actively length-stabilised fibre-links of the synchronisation system. The monitors are foreseen to be used as a standard diagnostic tool, not only for FLASH but also for the future European X-Ray Free-Electron Laser (European XFEL). The present bunch arrival time monitors have evolved from proof-of-principle experiments to beneficial diagnostic devices, which are almost permanently available during standard machine operation. This achievement has been a major objective of this thesis. The developments went in parallel to improvements in the reliable and low-maintenance operation of the optical synchronisation system. The key topics of this thesis comprised the characterisation and optimisation of the opto-mechanical front-ends of both, the fibre-links and the BAMs. The extent of applications involving the bunch arrival time information has been enlarged, providing automated measurements for properties of the RF acceleration modules, for instance, the RF on-crest phase determination and the measurement of energy fluctuations. Furthermore, two of the currently installed BAMs are implemented in an active phase and gradient stabilisation of specific modules in order to minimise the arrival time jitter of the electron bunches at the location of the FEL undulators, which is crucial for a high timing resolution of pump-probe experiments.

  5. Measuring the electron bunch timing with femtosecond resolution at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Bock, Marie Kristin

    2013-03-15

    Bunch arrival time monitors (BAMs) are an integral part of the laser-based synchronisation system which is being developed at the Free Electron Laser in Hamburg (FLASH).The operation principle comprises the measurement of the electron bunch arrival time relative to the optical timing reference, which is provided by actively length-stabilised fibre-links of the synchronisation system. The monitors are foreseen to be used as a standard diagnostic tool, not only for FLASH but also for the future European X-Ray Free-Electron Laser (European XFEL). The present bunch arrival time monitors have evolved from proof-of-principle experiments to beneficial diagnostic devices, which are almost permanently available during standard machine operation. This achievement has been a major objective of this thesis. The developments went in parallel to improvements in the reliable and low-maintenance operation of the optical synchronisation system. The key topics of this thesis comprised the characterisation and optimisation of the opto-mechanical front-ends of both, the fibre-links and the BAMs. The extent of applications involving the bunch arrival time information has been enlarged, providing automated measurements for properties of the RF acceleration modules, for instance, the RF on-crest phase determination and the measurement of energy fluctuations. Furthermore, two of the currently installed BAMs are implemented in an active phase and gradient stabilisation of specific modules in order to minimise the arrival time jitter of the electron bunches at the location of the FEL undulators, which is crucial for a high timing resolution of pump-probe experiments.

  6. Picosecond resolution on relativistic heavy ions' time-of-flight measurement

    Science.gov (United States)

    Ebran, A.; Taieb, J.; Belier, G.; Chatillon, A.; Laurent, B.; Martin, J.-F.; Pellereau, E.

    2013-11-01

    We developed a time-of-flight measurement system for relativistic heavy ions with a requested resolution of 40 ps Full Width Half Maximum. Such a resolution is mandatory to assign the correct mass number to every fission fragment, identified using the Bρ-ToF-ΔE method with the recoil spectrometer designed for the SOFIA experiment-which hold very recently at GSI. To achieve such a performance, fast plastic scintillators read-out by dedicated photomultiplier tubes were chosen among other possible options. We have led several test-measurements from 2009 to 2011, in order to investigate: the effect of the addition of a quenching molecule in the scintillator's matrix, the influence of the detector's size and the impact of the photomultiplier tube. The contribution of the dedicated electronics is also characterized. Time-of-flight measurements were performed realized with electron pulses and relativistic heavy ions, respectively provided by the LASER driven electron-accelerator (ELSA) at CEA-DAM Ile-de-France and by the SIS18/FRS facility at GSI. The reported results exhibit a time resolution better than 20 ps Full Width Half Maximum reached with the last prototype at GSI with an Uranium beam. These results confirm that the SOFIA experiment should enable the measurement of the relativistic fission fragments' time-of-flight with the requested resolution.

  7. Picosecond resolution on relativistic heavy ions' time-of-flight measurement

    International Nuclear Information System (INIS)

    Ebran, A.; Taieb, J.; Belier, G.; Chatillon, A.; Laurent, B.; Martin, J.-F.; Pellereau, E.

    2013-01-01

    We developed a time-of-flight measurement system for relativistic heavy ions with a requested resolution of 40 ps Full Width Half Maximum. Such a resolution is mandatory to assign the correct mass number to every fission fragment, identified using the Bρ-ToF-ΔE method with the recoil spectrometer designed for the SOFIA experiment—which hold very recently at GSI. To achieve such a performance, fast plastic scintillators read-out by dedicated photomultiplier tubes were chosen among other possible options. We have led several test-measurements from 2009 to 2011, in order to investigate: the effect of the addition of a quenching molecule in the scintillator's matrix, the influence of the detector's size and the impact of the photomultiplier tube. The contribution of the dedicated electronics is also characterized. Time-of-flight measurements were performed realized with electron pulses and relativistic heavy ions, respectively provided by the LASER driven electron–accelerator (ELSA) at CEA–DAM Ile-de-France and by the SIS18/FRS facility at GSI. The reported results exhibit a time resolution better than 20 ps Full Width Half Maximum reached with the last prototype at GSI with an Uranium beam. These results confirm that the SOFIA experiment should enable the measurement of the relativistic fission fragments' time-of-flight with the requested resolution

  8. Simulations of the temporal and spatial resolution for a compact time-resolved electron diffractometer

    Science.gov (United States)

    Robinson, Matthew S.; Lane, Paul D.; Wann, Derek A.

    2016-02-01

    A novel compact electron gun for use in time-resolved gas electron diffraction experiments has recently been designed and commissioned. In this paper we present and discuss the extensive simulations that were performed to underpin the design in terms of the spatial and temporal qualities of the pulsed electron beam created by the ionisation of a gold photocathode using a femtosecond laser. The response of the electron pulses to a solenoid lens used to focus the electron beam has also been studied. The simulated results show that focussing the electron beam affects the overall spatial and temporal resolution of the experiment in a variety of ways, and that factors that improve the resolution of one parameter can often have a negative effect on the other. A balance must, therefore, be achieved between spatial and temporal resolution. The optimal experimental time resolution for the apparatus is predicted to be 416 fs for studies of gas-phase species, while the predicted spatial resolution of better than 2 nm-1 compares well with traditional time-averaged electron diffraction set-ups.

  9. Performance evaluation of optimization methods for super-resolution mosaicking on UAS surveillance videos

    Science.gov (United States)

    Camargo, Aldo; He, Qiang; Palaniappan, K.

    2012-06-01

    Unmanned Aircraft Systems (UAS) have been widely applied into military reconnaissance and surveillance by exploiting the information collected from the digital imaging payload. However, the data analysis of UAS videos is frequently limited by motion blur; the frame-to-frame movement induced by aircraft roll, wind gusts, and less than ideal atmospheric conditions; and the noise inherent within the image sensors. Therefore, the super-resolution mosaicking on low-resolution UAS surveillance video frames, becomes an important task for UAS video processing and is a pre-step for further effective image understanding. Here we develop a novel super-resolution framework which does not require the construction of sparse matrices. This method applied image operators in spatial domain and adopted an iterated back-projection method to conduct super-resolution mosaics from UAS surveillance video frames. The Steepest Descent method, Conjugate Gradient method and Levenberg Marquardt algorithm are used to numerically solve the nonlinear optimization problem in the modeling of super-resolution mosaic. A quantity comparison in computation time and visual performance of the super-resolution using the three numerical methods is performed. The Levenberg Marquardt algorithm provides a numerical solution to the least squares curve fitting, which avoids the time-consuming computation of the inverse of the pseudo Hessian matrix in regular singular value decomposition (SVD). The Levenberg Marquardt method, interpolating between the Gauss-Newton algorithm (GNA) and the method of gradient descent, is efficient, robust, and easy to implement. The results obtained in our simulations shows a great improvement of the resolution of the low resolution mosaic of up to 47.54 dB for synthetic images, and a considerable visual improvement in sharpness and visual details for real UAS surveillance frames. The convergence is generally reached in no more than ten iterations.

  10. 10 microsecond time resolution studies of Cygnus X-1

    Energy Technology Data Exchange (ETDEWEB)

    Wen, H. C. [Stanford Univ., CA (United States)

    1997-06-01

    Time variability analyses have been applied to data composed of event times of X-rays emitted from the binary system Cygnus X-1 to search for unique black hole signatures. The X-ray data analyzed was collected at ten microsecond time resolution or better from two instruments, the High Energy Astrophysical Observatory (HEAO) A-1 detector and the Rossi X-ray Timing Explorer (XTE) Proportional Counter Array (PCA). HEAO A-1 and RXTE/PCA collected data from 1977--79 and from 1996 on with energy sensitivity from 1--25 keV and 2--60 keV, respectively. Variability characteristics predicted by various models of an accretion disk around a black hole have been searched for in the data. Drop-offs or quasi-periodic oscillations (QPOs) in the Fourier power spectra are expected from some of these models. The Fourier spectral technique was applied to the HEAO A-1 and RXTE/PCA data with careful consideration given for correcting the Poisson noise floor for instrumental effects. Evidence for a drop-off may be interpreted from the faster fall off in variability at frequencies greater than the observed breaks. Both breaks occur within the range of Keplerian frequencies associated with the inner edge radii of advection-dominated accretion disks predicted for Cyg X-1. The break between 10--20 Hz is also near the sharp rollover predicted by Nowak and Wagoner`s model of accretion disk turbulence. No QPOs were observed in the data for quality factors Q > 9 with a 95% confidence level upper limit for the fractional rms amplitude at 1.2% for a 16 M⊙ black hole.

  11. High energy resolution and first time-dependent positron annihilation induced Auger electron spectroscopty

    International Nuclear Information System (INIS)

    Mayer, Jakob

    2010-01-01

    It was the aim of this thesis to improve the existing positron annihilation induced Auger spectrometer at the highly intense positron source NEPOMUC (NEutron induced POsitron source MUniCh) in several ways: Firstly, the measurement time for a single spectrum should be reduced from typically 12 h to roughly 1 h or even less. Secondly, the energy resolution, which amounted to ΔE/E∼10%, should be increased by at least one order of magnitude in order to make high resolution positron annihilation induced Auger spectroscopy (PAES)-measurements of Auger transitions possible and thus deliver more information about the nature of the Auger process. In order to achieve these objectives, the PAES spectrometer was equipped with a new electron energy analyzer. For its ideal operation all other components of the Auger analysis chamber had to be adapted. Particularly the sample manipulation and the positron beam guidance had to be renewed. Simulations with SIMION registered ensured the optimal positron lens parameters. After the adjustment of the new analyzer and its components, first measurements illustrated the improved performance of the PAES setup: Firstly, the measurement time for short overview measurements was reduced from 3 h to 420 s. The measurement time for more detailed Auger spectra was shortened from 12 h to 80 min. Secondly, even with the reduced measurement time, the signal to noise ratio was also enhanced by one order of magnitude. Finally, the energy resolution was improved to ΔE/E 2,3 VV-transition with PAES. Thus, within this thesis two objectives were achieved: Firstly, the PAES spectrometer was renewed and improved by at least one order of magnitude with respect to the signal to noise ratio, the measurement time and the energy resolution. Secondly, several measurements have been carried out, demonstrating the high performance of the spectrometer. Amongst them are first dynamic PAES measurements and a high resolution measurement of the CuM 2,3 VV

  12. High performance current generator with one-picoampere resolution

    International Nuclear Information System (INIS)

    Grillo, L.; Manfredi, P.F.; Marchesini, R.

    1975-01-01

    A high-performance current generator for the picoampere region is presented. Although it was primarily developed as a part of an automatic test system to calibrate charge integrators for accelerating machines. It can suit a wide range of applications. It consists basically of a positive feedback loop of controlled gain which includes a varactor bridge operational amplifier. The essential features of the instrument are a 1 pA resolution and a 10 15 Ω output impedance. The output is guarded and floating between - 120 V and + 120 V, and the voltage across the external loads is measured without affecting the delivered current by a digital panel meter on the front panel. The unit can therefore operate as a high-accuracy dc impedance meter. (Auth.)

  13. The Pleiades System High Resolution Optical Satellite and its Performances

    Science.gov (United States)

    Boussarie, E.

    France is setting up a cooperative program with Italy as main partner, including other european cooperative countries, in order to develop a dual use system. This means that it intends to be used by civilian users, and by military ones, as well. It will deliver optical images (part of the system developed under french responsibility), and radar images (part of the system developed under italian responsibility). This paper aims at describing the optical satellite inside the overall system. The Pléiades optical high resolution system is based upon the use of a satellite featuring a set of newly european developed technologies. This paper reports the status of the satellite development. It describes the newly developed technologies, explains the system sizing philosophy, and describes the performances status.

  14. Young weightlifters' performance across time.

    Science.gov (United States)

    Byrd, Ronald; Pierce, Kyle; Rielly, Lee; Brady, Jenny

    2003-01-01

    Prestigious professional organisations have questioned the efficacy of resistive training by children or have often neglected to address weightlifting in their position papers on resistive training for children. The purpose of this paper was to address the deficit in data regarding the efficacy of training children for weightlifting and to report data regarding to safety in this population. Eleven subjects (3 female, 8 male) who had trained at the USA Weightlifting Development Centre in Shreveport Louisiana for a minimum of 22 months (mean = 28.8; SD +/- 4.4) served as subjects for this study. Means for the pool of subjects subjected to t-test to compare data obtained at each subject's initial competition with that obtained at the individual's most recent competition revealed significant positive changes in body weight, snatch weight, clean and jerk weight, and total weight lifted. The latter three were significant both in absolute weight and in weight lifted per kg of body weight. Total weight lifted at competitions plotted separately for boys and for girls across time indicated an apparently steeper slope of improvement for boys. The latter were not tested for significance because of the small sample sizes. The lack of injury in training and in 534 competitive lifts was discussed. None required medical attention or loss of training time. It was concluded that there can be no doubt regarding the efficacy of weightlifting as carried out at the USA Weightlifting Development Centre. The importance of proper application of scientific theory of conditioning in a conservative manner for this population was emphasised.

  15. Time resolution deterioration with increasing crystal length in a TOF-PET system

    CERN Document Server

    Gundacker, S; Auffray, E; Jarron, P; Meyer, T; Lecoq, P

    2014-01-01

    Highest time resolution in scintillator based detectors is becoming more and more important. In medical detector physics L(Y)SO scintillators are commonly used for time of flight positron emission tomography (TOF-PET). Coincidence time resolutions (CTRs) smaller than 100 ps FWHM are desirable in order to improve the image signal to noise ratio and thus give benefit to the patient by shorter scanning times. Also in high energy physics there is the demand to improve the timing capabilities of calorimeters down to 10 ps. To achieve these goals it is important to study the whole chain, i.e. the high energy particle interaction in the crystal, the scintillation process itself, the scintillation light transfer in the crystal, the photodetector and the electronics. Time resolution measurements for a PET like system are performed with the time-over-threshold method in a coincidence setup utilizing the ultra-fast amplifier-discriminator NINO. With 2×2×3 mm3 LSO:Ce codoped 0.4%Ca crystals coupled to commercially avai...

  16. Test and characterisation of SiPMs for the MEGII high resolution Timing Counter

    Energy Technology Data Exchange (ETDEWEB)

    Simonetta, M., E-mail: marcello.simonetta@pv.infn.it [INFN-Pavia, Via A. Bassi 6, I-27100 Pavia (Italy); Dipartimento di Fisica dell' Università degli Studi di Pavia, Via A. Bassi 6, I-27100 Pavia (Italy); Biasotti, M. [INFN-Genova, Via Dodecaneso 33, I-16146 Genova (Italy); Dipartimento di Fisica dell' Università di Genova, Via Dodecaneso 33, I-16146 Genova (Italy); Boca, G. [INFN-Pavia, Via A. Bassi 6, I-27100 Pavia (Italy); Dipartimento di Fisica dell' Università degli Studi di Pavia, Via A. Bassi 6, I-27100 Pavia (Italy); Cattaneo, P.W. [INFN-Pavia, Via A. Bassi 6, I-27100 Pavia (Italy); De Gerone, M.; Gatti, F. [INFN-Genova, Via Dodecaneso 33, I-16146 Genova (Italy); Dipartimento di Fisica dell' Università di Genova, Via Dodecaneso 33, I-16146 Genova (Italy); Nardò, R. [INFN-Pavia, Via A. Bassi 6, I-27100 Pavia (Italy); Dipartimento di Fisica dell' Università degli Studi di Pavia, Via A. Bassi 6, I-27100 Pavia (Italy); Nishimura, M. [Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Ootani, W. [ICEPP, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Pizzigoni, G. [INFN-Genova, Via Dodecaneso 33, I-16146 Genova (Italy); Dipartimento di Fisica dell' Università di Genova, Via Dodecaneso 33, I-16146 Genova (Italy); Prata, M.C.; Rossella, M. [INFN-Pavia, Via A. Bassi 6, I-27100 Pavia (Italy); Shibata, N. [Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Uchiyama, Y. [ICEPP, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Yoshida, K. [Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2016-07-11

    The MEGII Timing Counter will measure the positron time of arrival with a resolution of ~ 30 ps relying on two arrays of scintillator pixels read out by 6144 Silicon Photomultipliers (SiPMs) from AdvanSiD. They are characterised, measuring their breakdown voltage, to assure that the gains of the SiPMs of each pixel are as uniform as possible, to maximise the pixel resolution. Gain measurements have also been performed. - Highlights: • Characterisation of SiPMs for MEG-II Timing Counter is illustrated. • SiPMs breakdown voltage and gain measurement are reported. • The criterion for the choice of each single pixel SiPMs is explained.

  17. Optimizing timing performance of CdTe detectors for PET

    Science.gov (United States)

    Nakhostin, M.

    2017-10-01

    Despite several attractive properties, the poor timing performance of compound semiconductor detectors such as CdTe and CdZnTe has hindered their use in commercial PET imaging systems. The standard method of pulse timing with such detectors is to employ a constant-fraction discriminator at the output of a timing filter which is fed by the pulses from a charge-sensitive preamplifier. The method has led to a time resolution of about 10 ns at full-width at half-maximum (FWHM) with 1 mm thick CdTe detectors. This paper presents a detailed investigation on the parameters limiting the timing performance of Ohmic contact planar CdTe detectors with the standard pulse timing method. The jitter and time-walk errors are studied through simulation and experimental measurements and it is revealed that the best timing results obtained with the standard timing method suffer from a significant loss of coincidence events (~50%). In order to improve the performance of the detectors with full detection efficiency, a new digital pulse timing method based on a simple pattern recognition technique was developed. A time resolution of 3.29  ±  0.10 ns (FWHM) in the energy range of 300-650 keV was achieved with an Ohmic contact planar CdTe detector (5  ×  5  ×  1 mm3). The digital pulse processing method was also used to correct for the charge-trapping effect and an improvement in the energy resolution from 4.83  ±  0.66% to 2.780  ±  0.002% (FWHM) at 511 keV was achieved. Further improvement of time resolution through a moderate cooling of the detector and the application of the method to other detector structures are also discussed.

  18. A digital approach for real time high-rate high-resolution radiation measurements

    International Nuclear Information System (INIS)

    Gerardi, G.; Abbene, L.

    2014-01-01

    Modern spectrometers are currently developed by using digital pulse processing (DPP) systems, showing several advantages over traditional analog electronics. The aim of this work is to present digital strategies, in a time domain, for the development of real time high-rate high-resolution spectrometers. We propose a digital method, based on the single delay line (SDL) shaping technique, able to perform multi-parameter analysis with high performance even at high photon counting rates. A robust pulse shape and height analysis (PSHA), applied on single isolated time windows of the detector output waveforms, is presented. The potentialities of the proposed strategy are highlighted through both theoretical and experimental approaches. To strengthen our approach, the implementation of the method on a real-time system together with some experimental results are presented. X-ray spectra measurements with a semiconductor detector are performed both at low and high photon counting rates (up to 1.1 Mcps)

  19. A digital approach for real time high-rate high-resolution radiation measurements

    Energy Technology Data Exchange (ETDEWEB)

    Gerardi, G.; Abbene, L., E-mail: leonardo.abbene@unipa.it

    2014-12-21

    Modern spectrometers are currently developed by using digital pulse processing (DPP) systems, showing several advantages over traditional analog electronics. The aim of this work is to present digital strategies, in a time domain, for the development of real time high-rate high-resolution spectrometers. We propose a digital method, based on the single delay line (SDL) shaping technique, able to perform multi-parameter analysis with high performance even at high photon counting rates. A robust pulse shape and height analysis (PSHA), applied on single isolated time windows of the detector output waveforms, is presented. The potentialities of the proposed strategy are highlighted through both theoretical and experimental approaches. To strengthen our approach, the implementation of the method on a real-time system together with some experimental results are presented. X-ray spectra measurements with a semiconductor detector are performed both at low and high photon counting rates (up to 1.1 Mcps)

  20. High-Resolution Near Real-Time Drought Monitoring in South Asia

    Science.gov (United States)

    Aadhar, S.; Mishra, V.

    2017-12-01

    Drought in South Asia affect food and water security and pose challenges for millions of people. For policy-making, planning and management of water resources at the sub-basin or administrative levels, high-resolution datasets of precipitation and air temperature are required in near-real time. Here we develop a high resolution (0.05 degree) bias-corrected precipitation and temperature data that can be used to monitor near real-time drought conditions over South Asia. Moreover, the dataset can be used to monitor climatic extremes (heat waves, cold waves, dry and wet anomalies) in South Asia. A distribution mapping method was applied to correct bias in precipitation and air temperature (maximum and minimum), which performed well compared to the other bias correction method based on linear scaling. Bias-corrected precipitation and temperature data were used to estimate Standardized precipitation index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) to assess the historical and current drought conditions in South Asia. We evaluated drought severity and extent against the satellite-based Normalized Difference Vegetation Index (NDVI) anomalies and satellite-driven Drought Severity Index (DSI) at 0.05˚. We find that the bias-corrected high-resolution data can effectively capture observed drought conditions as shown by the satellite-based drought estimates. High resolution near real-time dataset can provide valuable information for decision-making at district and sub- basin levels.

  1. High-resolution near real-time drought monitoring in South Asia

    Science.gov (United States)

    Aadhar, Saran; Mishra, Vimal

    2017-10-01

    Drought in South Asia affect food and water security and pose challenges for millions of people. For policy-making, planning, and management of water resources at sub-basin or administrative levels, high-resolution datasets of precipitation and air temperature are required in near-real time. We develop a high-resolution (0.05°) bias-corrected precipitation and temperature data that can be used to monitor near real-time drought conditions over South Asia. Moreover, the dataset can be used to monitor climatic extremes (heat and cold waves, dry and wet anomalies) in South Asia. A distribution mapping method was applied to correct bias in precipitation and air temperature, which performed well compared to the other bias correction method based on linear scaling. Bias-corrected precipitation and temperature data were used to estimate Standardized precipitation index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) to assess the historical and current drought conditions in South Asia. We evaluated drought severity and extent against the satellite-based Normalized Difference Vegetation Index (NDVI) anomalies and satellite-driven Drought Severity Index (DSI) at 0.05°. The bias-corrected high-resolution data can effectively capture observed drought conditions as shown by the satellite-based drought estimates. High resolution near real-time dataset can provide valuable information for decision-making at district and sub-basin levels.

  2. Design and performance evaluation of a high resolution IRI-microPET preclinical scanner

    Energy Technology Data Exchange (ETDEWEB)

    Islami rad, S.Z., E-mail: szislami@yahoo.com [Department of Physic, Faculty of Science, University of Qom, Qom (Iran, Islamic Republic of); Peyvandi, R. Gholipour; Lehdarboni, M. Askari; Ghafari, A.A. [Instrumentation Research Group, Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of)

    2015-05-01

    PET for small animal, IRI-microPET, was designed and built at the NSTRI. The scanner is made of four detectors positioned on a rotating gantry at a distance 50 mm from the center. Each detector consists of a 10×10 crystal matrix of 2×2×10 mm{sup 3} directly coupled to a PS-PMT. A position encoding circuit for specific PS-PMT has been designed, built and tested with a PD-MFS-2MS/s-8/14 data acquisition board. After implementing reconstruction algorithms (FBP, MLEM and SART) on sinograms, images quality and system performance were evaluated by energy resolution, timing resolution, spatial resolution, scatter fraction, sensitivity, RMS contrast and SNR parameters. The energy spectra were obtained for the crystals with an energy window of 300–700 keV. The energy resolution in 511 keV averaged over all modules, detectors, and crystals, was 23.5%. A timing resolution of 2.4 ns FWHM obtained by coincidence timing spectrum was measured with crystal LYSO. The radial and tangential resolutions for {sup 18}F (1.15-mm inner diameter) at the center of the field of view were 1.81 mm and 1.90 mm, respectively. At a radial offset of 5 mm, the FWHM values were 1.96 and 2.06 mm. The system scatter fraction was 7.1% for the mouse phantom. The sensitivity was measured for different energy windows, leading to a sensitivity of 1.74% at the center of FOV. Also, images quality was evaluated by RMS contrast and SNR factors, and the results show that the reconstructed images by MLEM algorithm have the best RMS contrast, and SNR. The IRI-microPET presents high image resolution, low scatter fraction values and improved SNR for animal studies.

  3. Evaluating SWAT Predictive Performance Based on Different Spatial Resolution Climatic Data

    Science.gov (United States)

    Tedla Shiferaw, Elias; Singh, Shailesh Kumar; Bárdossy, András.

    2010-05-01

    Complex Physically based hydrological models require sufficient, detailed, and complex data which represents the overall systems in the respective catchment. Subsequently, the predictive performance of these models is highly influenced by scale of data measurement both in terms of space and time. Soil and Water Assessment Tool (SWAT) was developed to predict the impact of land management practices on water, sediment and agricultural chemical yields in large complex watershed with varying soil, land use and management conditions over long period of times. In this study an attempt has been made to evaluate SWAT predictive performance in two different regions of catchment with different spatial resolution climatic data. Catchments from Ethiopia and Germany have been chosen for the collection of climatic time series data. Data availability at both the catchments is different. German catchments have good data availability at fine resolution; where as counter catchments in Ethiopia have very course and less data. ArcSWAT2.3.4 of the SWAT2005 version for ArcGIS9.3 was used for this study. Calibration and Sensitivity analyses were implemented to parameterize the model for the both the catchments. It has been found that the spatial resolution of climatic data have significant influence on the predictive performance of the SWAT model. The simulation result seems promising and gives a better understanding how the scale can have great impact on the models performance.

  4. Influence of horizontal resolution and ensemble size on model performance

    CSIR Research Space (South Africa)

    Dalton, A

    2014-10-01

    Full Text Available Computing costs increase with an increase in global model resolution and ensemble size. This paper strives to determine the extent to which resolution and ensemble size affect seasonal forecast skill when simulating mid-summer rainfall totals over...

  5. Measuring the performance of super-resolution reconstruction algorithms

    NARCIS (Netherlands)

    Dijk, J.; Schutte, K.; Eekeren, A.W.M. van; Bijl, P.

    2012-01-01

    For many military operations situational awareness is of great importance. This situational awareness and related tasks such as Target Acquisition can be acquired using cameras, of which the resolution is an important characteristic. Super resolution reconstruction algorithms can be used to improve

  6. On the resolution and intensity of a time-of-flight neutron reflectometer

    International Nuclear Information System (INIS)

    Well, A.A. van; Fredrikze, H.

    2005-01-01

    In a neutron reflection experiment, the reflectivity is determined as a function of wave-vector transfer q=4πθ/λ, with θ the glancing angle and λ the neutron wavelength. At a continuous neutron source, it may be advantageous to use the time-of-flight technique to determine λ. Then, a chopper system is used to pulse the beam. We will discuss all contributions to both q resolution and intensity. Special attention is paid to the comparison of using a single- and double-disc chopper system. Examples of the performance of both systems are given. The double-disc chopper produces a burst time proportional to λ. By matching the different contributions to the resolution, the resulting intensity can be optimised

  7. Investigation of electron emission energy composition from micro-pinch discharge plasma with time resolution

    International Nuclear Information System (INIS)

    Gulin, M.A.; Dolgov, A.N.; Kirichenko, N.N.; Savelov, A.S.

    1995-01-01

    Time features of electron emission from micro-pinch discharge plasma are investigated. Detection of > 25 keV energy electrons, emitted in the axial direction and x radiation with > 2 keV quantum energy is performed with nanosecond time resolution using a multichannel system of scintillation detectors. Comparison of amplitude ratio of electron signals from two detectors, placed behind aluminium filters, to the estimated ratio, corresponding to one-component temperature model of particle energy spectrum, allows one to distinguish two groups of emitted electrons: one is characterized by effective kT e e > 30 keV. 9 refs., 5 figs., 1 tab

  8. High frequency, high time resolution time-to-digital converter employing passive resonating circuits

    Energy Technology Data Exchange (ETDEWEB)

    Ripamonti, Giancarlo; Abba, Andrea; Geraci, Angelo [Department of Electronics, Politecnico di Milano, via C. Golgi 40, Milano 20133 (Italy)

    2010-05-15

    A method for measuring time intervals accurate to the picosecond range is based on phase measurements of oscillating waveforms synchronous with their beginning and/or end. The oscillation is generated by triggering an LC resonant circuit, whose capacitance is precharged. By using high Q resonators and a final active quenching of the oscillation, it is possible to conjugate high time resolution and a small measurement time, which allows a high measurement rate. Methods for fast analysis of the data are considered and discussed with reference to computing resource requirements, speed, and accuracy. Experimental tests show the feasibility of the method and a time accuracy better than 4 ps rms. Methods aimed at further reducing hardware resources are finally discussed.

  9. Timing performance of ZnO:Ga nanopowder composite scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Turtos, Rosana M. [Universita degli Studi di Milano-Bicocca, Milano (Italy); Gundacker, Stefan; Lucchini, Marco T.; Lecoq, Paul; Auffray, Etiennette [CERN, Geneva (Switzerland); Prochazkova, Lenka; Cuba, Vaclav [Czech Technical University, Faculty of Nuclear Sciences and Physical Engineering, Prague (Czech Republic); Buresova, Hana [Nuvia a.s, Kralupy nad Vltavou (Czech Republic); Mrazek, Jan [Institute of Photonics and Electronics AS CR, Prague (Czech Republic); Nikl, Martin [Institute of Physics of the AS CR, Prague (Czech Republic)

    2016-11-15

    The implementation of nanocrystal-based composite scintillators as a new generation of ultrafast particle detectors is explored using ZnO:Ga nanopowder. Samples are characterized with a spectral-time resolved photon counting system and pulsed X-rays, followed by coincidence time resolution (CTR) measurements under 511 keV gamma excitation. Results are comparable to CTR values obtained using bulk inorganic scintillators. Bringing the ZnO:Ga nanocrystal's timing performance to radiation detectors could pave the research path towards sub-20 ps time resolution as shown in this contribution. However, an efficiency boost when placing nanopowders in a transparent host constitutes the main challenge in order to benefit from sub-nanosecond recombination times. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Investigation of digital timing resolution and further improvement by using constant fraction signal time marker slope for fast scintillator detectors

    Science.gov (United States)

    Singh, Kundan; Siwal, Davinder

    2018-04-01

    A digital timing algorithm is explored for fast scintillator detectors, viz. LaBr3, BaF2, and BC501A. Signals were collected with CAEN 250 mega samples per second (MSPS) and 500 MSPS digitizers. The zero crossing time markers (TM) were obtained with a standard digital constant fraction timing (DCF) method. Accurate timing information is obtained using cubic spline interpolation of a DCF transient region sample points. To get the best time-of-flight (TOF) resolution, an optimization of DCF parameters is performed (delay and constant fraction) for each pair of detectors: (BaF2-LaBr3), (BaF2-BC501A), and (LaBr3-BC501A). In addition, the slope information of an interpolated DCF signal is extracted at TM position. This information gives a new insight to understand the broadening in TOF, obtained for a given detector pair. For a pair of signals having small relative slope and interpolation deviations at TM, leads to minimum time broadening. However, the tailing in TOF spectra is dictated by the interplay between the interpolation error and slope variations. Best TOF resolution achieved at the optimum DCF parameters, can be further improved by using slope parameter. Guided by the relative slope parameter, events selection can be imposed which leads to reduction in TOF broadening. While the method sets a trade-off between timing response and coincidence efficiency, it provides an improvement in TOF. With the proposed method, the improved TOF resolution (FWHM) for the aforementioned detector pairs are; 25% (0.69 ns), 40% (0.74 ns), 53% (0.6 ns) respectively, obtained with 250 MSPS, and corresponds to 12% (0.37 ns), 33% (0.72 ns), 35% (0.69 ns) respectively with 500 MSPS digitizers. For the same detector pair, event survival probabilities are; 57%, 58%, 51% respectively with 250 MSPS and becomes 63%, 57%, 68% using 500 MSPS digitizers.

  11. SiPM Photodetectors for Highest Time Resolution in PET

    CERN Document Server

    Gundacker, S; Meyer, T; Lecoq, P; Jarron, P; Frisch, B

    2012-01-01

    Mesh anode Vacuum Phototriodes (VPTs) are radiation resistant, single gain-stage photomultipliers which are designed to operate in a strong quasi-axial magnetic field. These VPTs are used in the endcap electromagnetic calorimeter of the CMS experiment at the CERN LHC to detect scintillation light from lead tungstate crystals. Short term dynamic response changes occur because of pulse rate variations during normal LHC operation cycles. Over the longer term the effect of increasing integrated charge taken from the photocathode causes an overall degradation of response. We have investigated these effects over time periods exceeding two years of simulated operation and discuss the implications for the long term performance of the VPTs in CMS.

  12. Time-lapse high-resolution seismic surveys in the Mississippi Delta mudflow area, offshore Louisiana

    Energy Technology Data Exchange (ETDEWEB)

    Son-Hindmarsh, R.; Hughson, R.A.; Ploessel, M.R.

    1984-05-01

    Time-lapse high-resolution surveys are useful for studying rapidly changing geologic features such as the mudflows of the Mississippi Delta, and for assessing how these potentially hazardous features might affect offshore structures. For time-lapse surveys, an initial high-resolution seismic survey is repeated at specified time intervals, following the same grid of tracklines, using the same seismic systems and a precise navigation system. Time-lapse surveys have been used successfully to monitor the active mudflow about 6 miles upslope from Shell Offshore Inc.'s Cognac Platform. The surveys show that mudflow activity has had no effect on the Platform. Time-lapse surveys obtain the most accurate determination of seafloor changes available at the present time. If one compares two or more random surveys in an area, instead of carefully performed time-lapse surveys, the accuracy of the results may be less than the actural amount of change; so results may be meaningless or misleading. Time-lapse surveys can produce results with vertical accuracy of about + or 5 feet along survey tracklines.

  13. Performance of a high resolution cavity beam position monitor system

    International Nuclear Information System (INIS)

    Walston, Sean; Boogert, Stewart; Chung, Carl; Fitsos, Pete; Frisch, Joe; Gronberg, Jeff; Hayano, Hitoshi; Honda, Yosuke; Kolomensky, Yury; Lyapin, Alexey; Malton, Stephen; May, Justin; McCormick, Douglas; Meller, Robert; Miller, David; Orimoto, Toyoko; Ross, Marc; Slater, Mark; Smith, Steve; Smith, Tonee; Terunuma, Nobuhiro; Thomson, Mark; Urakawa, Junji; Vogel, Vladimir; Ward, David; White, Glen

    2007-01-01

    It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than 1nm. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6nm and a tilt resolution of 2.1μrad over a dynamic range of approximately +/-20μm

  14. Performance of a High Resolution Cavity Beam Position Monitor System

    Energy Technology Data Exchange (ETDEWEB)

    Walston, S; Boogert, S; Chung, C; Fitsos, P; Frisch, J; Gronberg, J; Hayano, H; Honda, Y; Kolomensky, Y; Lyapin, A; Malton, S; May, J; McCormick, D; Meller, R; Miller, D; Orimoto, T; Ross, M; Slater, M; Smith, S; Smith, T; Terunuma, N; Thomson, M; Urakawa, J; Vogel, V; Ward, D; White, G

    2006-12-18

    It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than one nanometer. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6 nm and a tilt resolution of 2.1 {micro}rad over a dynamic range of approximately {+-} 20 {micro}m.

  15. Performance of a High Resolution Cavity Beam Position Monitor System

    Energy Technology Data Exchange (ETDEWEB)

    Walston, Sean; Boogert, Stewart; Chung, Carl; Fitsos, Joe; Frisch, Joe; Gronberg, Jeff; Hayano, Hitoshi; Honda, Yosuke; Kolomensky, Yury; Lyapin, Alexey; Malton, Stephen; May, Justin; McCormick, Douglas; Meller, Robert; Miller, David John; Orimoto, Toyoko; Ross, Marc; Slater, Mark; Smith, Steve; Smith, Tonee; Terunuma, Nobuhiro; /Fermilab /UC,

    2007-06-08

    It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than one nanometer. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6 nm and a tilt resolution of 2.1 {mu}rad over a dynamic range of approximately {+-} 20 {mu}m.

  16. Improved-Resolution, Real-Time Skin-Dose Mapping for Interventional Fluoroscopic Procedures.

    Science.gov (United States)

    Rana, Vijay K; Rudin, Stephen; Bednarek, Daniel R

    2014-03-19

    We have developed a dose-tracking system (DTS) that provides a real-time display of the skin-dose distribution on a 3D patient graphic during fluoroscopic procedures. Radiation dose to individual points on the skin is calculated using exposure and geometry parameters from the digital bus on a Toshiba C-arm unit. To accurately define the distribution of dose, it is necessary to use a high-resolution patient graphic consisting of a large number of elements. In the original DTS version, the patient graphics were obtained from a library of population body scans which consisted of larger-sized triangular elements resulting in poor congruence between the graphic points and the x-ray beam boundary. To improve the resolution without impacting real-time performance, the number of calculations must be reduced and so we created software-designed human models and modified the DTS to read the graphic as a list of vertices of the triangular elements such that common vertices of adjacent triangles are listed once. Dose is calculated for each vertex point once instead of the number of times that a given vertex appears in multiple triangles. By reformatting the graphic file, we were able to subdivide the triangular elements by a factor of 64 times with an increase in the file size of only 1.3 times. This allows a much greater number of smaller triangular elements and improves resolution of the patient graphic without compromising the real-time performance of the DTS and also gives a smoother graphic display for better visualization of the dose distribution.

  17. High time resolution measurements of the thermosphere from Fabry-Perot Interferometer measurements of atomic oxygen

    Directory of Open Access Journals (Sweden)

    E. A. K. Ford

    2007-06-01

    Full Text Available Recent advances in the performance of CCD detectors have enabled a high time resolution study of the high latitude upper thermosphere with Fabry-Perot Interferometers (FPIs to be performed. 10-s integration times were used during a campaign in April 2004 on an FPI located in northern Sweden in the auroral oval. The FPI is used to study the thermosphere by measuring the oxygen red line emission at 630.0 nm, which emits at an altitude of approximately 240 km. Previous time resolutions have been 4 min at best, due to the cycle of look directions normally observed. By using 10 s rather than 40 s integration times, and by limiting the number of full cycles in a night, high resolution measurements down to 15 s were achievable. This has allowed the maximum variability of the thermospheric winds and temperatures, and 630.0 nm emission intensities, at approximately 240 km, to be determined as a few minutes. This is a significantly greater variability than the often assumed value of 1 h or more. A Lomb-Scargle analysis of this data has shown evidence of gravity wave activity with waves with short periods. Gravity waves are an important feature of mesosphere-lower thermosphere (MLT dynamics, observed using many techniques and providing an important mechanism for energy transfer between atmospheric regions. At high latitudes gravity waves may be generated in-situ by localised auroral activity. Short period waves were detected in all four clear nights when this experiment was performed, in 630.0 nm intensities and thermospheric winds and temperatures. Waves with many periodicities were observed, from periods of several hours, down to 14 min. These waves were seen in all parameters over several nights, implying that this variability is a typical property of the thermosphere.

  18. Universal behavior of the interoccurrence times between losses in financial markets: independence of the time resolution.

    Science.gov (United States)

    Ludescher, Josef; Bunde, Armin

    2014-12-01

    We consider representative financial records (stocks and indices) on time scales between one minute and one day, as well as historical monthly data sets, and show that the distribution P(Q)(r) of the interoccurrence times r between losses below a negative threshold -Q, for fixed mean interoccurrence times R(Q) in multiples of the corresponding time resolutions, can be described on all time scales by the same q exponentials, P(Q)(r)∝1/{[1+(q-1)βr](1/(q-1))}. We propose that the asset- and time-scale-independent analytic form of P(Q)(r) can be regarded as an additional stylized fact of the financial markets and represents a nontrivial test for market models. We analyze the distribution P(Q)(r) as well as the autocorrelation C(Q)(s) of the interoccurrence times for three market models: (i) multiplicative random cascades, (ii) multifractal random walks, and (iii) the generalized autoregressive conditional heteroskedasticity [GARCH(1,1)] model. We find that only one of the considered models, the multifractal random walk model, approximately reproduces the q-exponential form of P(Q)(r) and the power-law decay of C(Q)(s).

  19. Universal behavior of the interoccurrence times between losses in financial markets: Independence of the time resolution

    Science.gov (United States)

    Ludescher, Josef; Bunde, Armin

    2014-12-01

    We consider representative financial records (stocks and indices) on time scales between one minute and one day, as well as historical monthly data sets, and show that the distribution PQ(r ) of the interoccurrence times r between losses below a negative threshold -Q , for fixed mean interoccurrence times RQ in multiples of the corresponding time resolutions, can be described on all time scales by the same q exponentials, PQ(r ) ∝1 /{[1+(q -1 ) β r ] 1 /(q -1 )} . We propose that the asset- and time-scale-independent analytic form of PQ(r ) can be regarded as an additional stylized fact of the financial markets and represents a nontrivial test for market models. We analyze the distribution PQ(r ) as well as the autocorrelation CQ(s ) of the interoccurrence times for three market models: (i) multiplicative random cascades, (ii) multifractal random walks, and (iii) the generalized autoregressive conditional heteroskedasticity [GARCH(1,1)] model. We find that only one of the considered models, the multifractal random walk model, approximately reproduces the q -exponential form of PQ(r ) and the power-law decay of CQ(s ) .

  20. Hypoxia: Exposure Time Until Significant Performance Effects

    Science.gov (United States)

    2016-03-07

    1994). Acute hypoxia fails to influence two aspects of short-term memory : implications for the source of cognitive deficits. Aviation, Space...Naval Medical Research Unit Dayton HYPOXIA : EXPOSURE TIME UNTIL SIGNIFICANT PERFORMANCE EFFECTS PHILLIPS, J.P., DRUMMOND, L.A...Andrews, CAPT, MSC, USN Commanding Officer i 1 ARTICLE TYPE: Research Article TITLE: Hypoxia : Exposure Time Until Significant Performance

  1. Constraint Logic Programming for Resolution of Relative Time Expressions

    DEFF Research Database (Denmark)

    Christiansen, Henning

    2014-01-01

    Translating time expression into absolute time points or durations is a challenge for natural languages processing such as text mining and text understanding in general. We present a constraint logic language CLP(Time) tailored to text usages concerned with time and calendar. It provides a simple...... and flexible formalism to express relationships between different time expressions in a text, thereby giving a recipe for resolving them into absolute time. A constraint solver is developed which, as opposed to some earlier approaches, is independent of the order in which temporal information is introduced......, and it can give meaningful output also when no exact reference time is available....

  2. High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors

    DEFF Research Database (Denmark)

    Andersen, Thomas; Jensen, Robert; Christensen, M. K.

    2012-01-01

    We demonstrate a combined microreactor and time of flight system for testing and characterization of heterogeneous catalysts with high resolution mass spectrometry and high sensitivity. Catalyst testing is performed in silicon-based microreactors which have high sensitivity and fast thermal...... response. Gas analysis is performed with a time of flight mass spectrometer with a modified nude Bayard-Alpert ionization gauge as gas ionization source. The mass resolution of the time of flight mass spectrometer using the ion gauge as ionization source is estimated to m∕Δm > 2500. The system design...... is superior to conventional batch and flow reactors with accompanying product detection by quadrupole mass spectrometry or gas chromatography not only due to the high sensitivity, fast temperature response, high mass resolution, and fast acquisition time of mass spectra but it also allows wide mass range (0...

  3. Highly segmented, high resolution time-of-flight system

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, T.K.; Nagamiya, S.; Vossnack, O.; Wu, Y.D.; Zajc, W.A. [Columbia Univ., New York, NY (United States); Miake, Y.; Ueno, S.; Kitayama, H.; Nagasaka, Y.; Tomizawa, K.; Arai, I.; Yagi, K [Univ. of Tsukuba, (Japan)

    1991-12-31

    The light attenuation and timing characteristics of time-of-flight counters constructed of 3m long scintillating fiber bundles of different shapes and sizes are presented. Fiber bundles made of 5mm diameter fibers showed good timing characteristics and less light attenuation. The results for a 1.5m long scintillator rod are also presented.

  4. Pathophysiological Distortions in Time Perception and Timed Performance

    Science.gov (United States)

    Allman, Melissa J.; Meck, Warren H.

    2012-01-01

    Distortions in time perception and timed performance are presented by a number of different neurological and psychiatric conditions (e.g. Parkinson's disease, schizophrenia, attention deficit hyperactivity disorder and autism). As a consequence, the primary focus of this review is on factors that define or produce systematic changes in the…

  5. A review on high-resolution CMOS delay lines: towards sub-picosecond jitter performance.

    Science.gov (United States)

    Abdulrazzaq, Bilal I; Abdul Halin, Izhal; Kawahito, Shoji; Sidek, Roslina M; Shafie, Suhaidi; Yunus, Nurul Amziah Md

    2016-01-01

    A review on CMOS delay lines with a focus on the most frequently used techniques for high-resolution delay step is presented. The primary types, specifications, delay circuits, and operating principles are presented. The delay circuits reported in this paper are used for delaying digital inputs and clock signals. The most common analog and digitally-controlled delay elements topologies are presented, focusing on the main delay-tuning strategies. IC variables, namely, process, supply voltage, temperature, and noise sources that affect delay resolution through timing jitter are discussed. The design specifications of these delay elements are also discussed and compared for the common delay line circuits. As a result, the main findings of this paper are highlighting and discussing the followings: the most efficient high-resolution delay line techniques, the trade-off challenge found between CMOS delay lines designed using either analog or digitally-controlled delay elements, the trade-off challenge between delay resolution and delay range and the proposed solutions for this challenge, and how CMOS technology scaling can affect the performance of CMOS delay lines. Moreover, the current trends and efforts used in order to generate output delayed signal with low jitter in the sub-picosecond range are presented.

  6. High energy resolution and first time-dependent positron annihilation induced Auger electron spectroscopty

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Jakob

    2010-04-03

    It was the aim of this thesis to improve the existing positron annihilation induced Auger spectrometer at the highly intense positron source NEPOMUC (NEutron induced POsitron source MUniCh) in several ways: Firstly, the measurement time for a single spectrum should be reduced from typically 12 h to roughly 1 h or even less. Secondly, the energy resolution, which amounted to {delta}E/E{approx}10%, should be increased by at least one order of magnitude in order to make high resolution positron annihilation induced Auger spectroscopy (PAES)-measurements of Auger transitions possible and thus deliver more information about the nature of the Auger process. In order to achieve these objectives, the PAES spectrometer was equipped with a new electron energy analyzer. For its ideal operation all other components of the Auger analysis chamber had to be adapted. Particularly the sample manipulation and the positron beam guidance had to be renewed. Simulations with SIMION {sup registered} ensured the optimal positron lens parameters. After the adjustment of the new analyzer and its components, first measurements illustrated the improved performance of the PAES setup: Firstly, the measurement time for short overview measurements was reduced from 3 h to 420 s. The measurement time for more detailed Auger spectra was shortened from 12 h to 80 min. Secondly, even with the reduced measurement time, the signal to noise ratio was also enhanced by one order of magnitude. Finally, the energy resolution was improved to {delta}E/E < 1. The exceptional surface sensitivity and elemental selectivity of PAES was demonstrated in measurements of Pd and Fe, both coated with Cu layers of varying thickness. PAES showed that with 0.96 monolayer of Cu on Fe, more than 55% of the detected Auger electrons stem from Cu. In the case of the Cu coated Pd sample 0.96 monolayer of Cu resulted in a Cu Auger fraction of more than 30% with PAES and less than 5% with electron induced Auger spectroscopy

  7. Experimental Performance of a Genetic Algorithm for Airborne Strategic Conflict Resolution

    Science.gov (United States)

    Karr, David A.; Vivona, Robert A.; Roscoe, David A.; DePascale, Stephen M.; Consiglio, Maria

    2009-01-01

    The Autonomous Operations Planner, a research prototype flight-deck decision support tool to enable airborne self-separation, uses a pattern-based genetic algorithm to resolve predicted conflicts between the ownship and traffic aircraft. Conflicts are resolved by modifying the active route within the ownship's flight management system according to a predefined set of maneuver pattern templates. The performance of this pattern-based genetic algorithm was evaluated in the context of batch-mode Monte Carlo simulations running over 3600 flight hours of autonomous aircraft in en-route airspace under conditions ranging from typical current traffic densities to several times that level. Encountering over 8900 conflicts during two simulation experiments, the genetic algorithm was able to resolve all but three conflicts, while maintaining a required time of arrival constraint for most aircraft. Actual elapsed running time for the algorithm was consistent with conflict resolution in real time. The paper presents details of the genetic algorithm's design, along with mathematical models of the algorithm's performance and observations regarding the effectiveness of using complimentary maneuver patterns when multiple resolutions by the same aircraft were required.

  8. Time preferences, study effort, and academic performance

    NARCIS (Netherlands)

    Non, J.A.; Tempelaar, D.T.

    2014-01-01

    We analyze the relation between time preferences, study effort, and academic performance among first-year Business and Economics students. Time preferences are measured by stated preferences for an immediate payment over larger delayed payments. Data on study efforts are derived from an electronic

  9. Competition, Time Horizon and Corporate Social Performance

    NARCIS (Netherlands)

    Graafland, J.J.; Smid, H.

    2013-01-01

    Abstract: This paper develops and tests a conceptual framework on the relationships between competition, time horizon and corporate social performance (CSP). We hypothesize that more intense competition discourages CSP by lowering the time horizon of companies. We test the hypothesis on a sample of

  10. Millisecond time resolution neutron reflection from a nematic liquid crystal

    International Nuclear Information System (INIS)

    Dalgliesh, R.M.; Lau, Y.G.J.; Richardson, R.M.; Riley, D.J.

    2004-01-01

    The director reorientation of the liquid crystal 4,4' octyl cyanobiphenyl in the nematic phase under application of bursts of ac field have been observed using time-resolved neutron scattering in reflection geometry. The relaxation of the director has been shown to agree with existing theory, as determined by material and cell parameters. This result shows that it is possible to use neutron reflection measurements from buried interfaces to follow kinetic processes on a time scale comparable with the pulse length of the ISIS neutron source (20 ms)

  11. Timing Variations in Two Balkan Percussion Performances

    Directory of Open Access Journals (Sweden)

    Daniel Goldberg

    2016-01-01

    Full Text Available Many songs and dance pieces from the Balkan Peninsula employ aksak meter, in which two categorically different durations, long and short, coexist in the sequence of beats that performers emphasize and listeners move to. This paper analyzes the durations of aksak beats and measures in two recorded percussion performances that use a particular aksak beat sequence, long-short-short. The results suggest that the timing of beats varies in conjunction with factors including melodic grouping and interaction among members of a performing ensemble and audience. Timing variation linked to melodic groups occurs on a solo recording of a Macedonian Romani folk song. The performer, Muzafer Bizlim, taps an ostinato while singing, and the timing of his taps seems to mark some local and large-scale group boundaries. Melodic organization also seems relevant to the timing of beats and measures on a recording of Bulgarian percussionist Mitko Popov playing the tŭpan, a double-headed bass drum, in a small folk music ensemble. In Popov’s performance, however, timing differences might be related to characteristics of the ensemble dynamic, such as the coordination of multiple musical participants. These interpretations generate possibilities for future study of timing variations in relation to rhythm and meter.

  12. An advection-based model to increase the temporal resolution of PIV time series.

    Science.gov (United States)

    Scarano, Fulvio; Moore, Peter

    A numerical implementation of the advection equation is proposed to increase the temporal resolution of PIV time series. The method is based on the principle that velocity fluctuations are transported passively, similar to Taylor's hypothesis of frozen turbulence . In the present work, the advection model is extended to unsteady three-dimensional flows. The main objective of the method is that of lowering the requirement on the PIV repetition rate from the Eulerian frequency toward the Lagrangian one. The local trajectory of the fluid parcel is obtained by forward projection of the instantaneous velocity at the preceding time instant and backward projection from the subsequent time step. The trajectories are approximated by the instantaneous streamlines, which yields accurate results when the amplitude of velocity fluctuations is small with respect to the convective motion. The verification is performed with two experiments conducted at temporal resolutions significantly higher than that dictated by Nyquist criterion. The flow past the trailing edge of a NACA0012 airfoil closely approximates frozen turbulence , where the largest ratio between the Lagrangian and Eulerian temporal scales is expected. An order of magnitude reduction of the needed acquisition frequency is demonstrated by the velocity spectra of super-sampled series. The application to three-dimensional data is made with time-resolved tomographic PIV measurements of a transitional jet. Here, the 3D advection equation is implemented to estimate the fluid trajectories. The reduction in the minimum sampling rate by the use of super-sampling in this case is less, due to the fact that vortices occurring in the jet shear layer are not well approximated by sole advection at large time separation. Both cases reveal that the current requirements for time-resolved PIV experiments can be revised when information is poured from space to time . An additional favorable effect is observed by the analysis in the

  13. A design for a high resolution very-low-Q time-of flight diffractometer

    International Nuclear Information System (INIS)

    Hjelm, R. P.

    1998-01-01

    The design of a high resolution view low-Q time of flight diffractometer was motivated by the anticipated need to perform small-angle neutron scattering measurements at far lower momentum transfer and higher precision than currently available at either pulsed or steady state sources. In addition, it was recognized that flexibility in the configuration of the instrument and ease in which data is acquired are important. The design offers two configurations, a high intensity/very low Q geometry employing a focusing mirror and a medium to high Q-precision/low Q configuration using standard pinhole collimation geometry. The quality of the mirror optics is very important to the performance of the high intensity/very low Q configuration. We believe that the necessary technology exists to fabricate the high quality mirror optics required for the instrument

  14. Divided Timed and Continuous Timed Assessment Protocols and Academic Performance

    Science.gov (United States)

    Perucca, David.

    2013-01-01

    Children from a low socioeconomic status (SES) are exposed to numerous stress factors that are negatively associated with sustained attention and academic performance. This association suggests that the timed component of lengthy assessments may be unfair for students from such backgrounds, as they may have an inability to sustain attention during…

  15. Single-photon detectors combining high efficiency, high detection rates, and ultra-high timing resolution

    Directory of Open Access Journals (Sweden)

    Iman Esmaeil Zadeh

    2017-11-01

    Full Text Available Single-photon detection with high efficiency, high time resolution, low dark counts, and high photon detection rates is crucial for a wide range of optical measurements. Although efficient detectors have been reported before, combining all performance parameters in a single device remains a challenge. Here, we show a broadband NbTiN superconducting nanowire detector with an efficiency exceeding 92%, over 150 MHz photon detection rate, and a dark count rate below 130 Hz operated in a Gifford-McMahon cryostat. Furthermore, with careful optimization of the detector design and readout electronics, we reach an ultra-low system timing jitter of 14.80 ps (13.95 ps decoupled while maintaining high detection efficiencies (>75%.

  16. Large area spark counters with fine time and position resolution

    International Nuclear Information System (INIS)

    Ogawa, A.; Atwood, W.B.; Fujiwara, N.; Pestov, Yu.N.; Sugahara, R.

    1983-10-01

    Spark counters trace their history back over three decades but have been used in only a limited number of experiments. The key properties of these devices include their capability of precision timing (at the sub 100 ps level) and of measuring the position of the charged particle to high accuracy. At SLAC we have undertaken a program to develop these devices for use in high energy physics experiments involving large detectors. A spark counter of size 1.2 m x 0.1 m has been constructed and has been operating continuously in our test setup for several months. In this talk I will discuss some details of its construction and its properties as a particle detector. 14 references

  17. Design and Performance of a 1 mm3 Resolution Clinical PET System Comprising 3-D Position Sensitive Scintillation Detectors.

    Science.gov (United States)

    Hsu, David F C; Freese, David L; Reynolds, Paul D; Innes, Derek R; Levin, Craig S

    2018-04-01

    We are developing a 1-mm 3 resolution, high-sensitivity positron emission tomography (PET) system for loco-regional cancer imaging. The completed system will comprise two cm detector panels and contain 4 608 position sensitive avalanche photodiodes (PSAPDs) coupled to arrays of mm 3 LYSO crystal elements for a total of 294 912 crystal elements. For the first time, this paper summarizes the design and reports the performance of a significant portion of the final clinical PET system, comprising 1 536 PSAPDs, 98 304 crystal elements, and an active field-of-view (FOV) of cm. The sub-system performance parameters, such as energy, time, and spatial resolutions are predictive of the performance of the final system due to the modular design. Analysis of the multiplexed crystal flood histograms shows 84% of the crystal elements have>99% crystal identification accuracy. The 511 keV photopeak energy resolution was 11.34±0.06% full-width half maximum (FWHM), and coincidence timing resolution was 13.92 ± 0.01 ns FWHM at 511 keV. The spatial resolution was measured using maximum likelihood expectation maximization reconstruction of a grid of point sources suspended in warm background. The averaged resolution over the central 6 cm of the FOV is 1.01 ± 0.13 mm in the X-direction, 1.84 ± 0.20 mm in the Y-direction, and 0.84 ± 0.11 mm in the Z-direction. Quantitative analysis of acquired micro-Derenzo phantom images shows better than 1.2 mm resolution at the center of the FOV, with subsequent resolution degradation in the y-direction toward the edge of the FOV caused by limited angle tomography effects.

  18. Multi-resolution time series imagery for forest disturbance and regrowth monitoring in Queensland, Australia

    NARCIS (Netherlands)

    Schmidt, M.; Lucas, R.; Bunting, P.; Verbesselt, J.; Armston, J.

    2015-01-01

    High spatio-temporal resolution optical remote sensing data provide unprecedented opportunities to monitor and detect forest disturbance and loss. To demonstrate this potential, a 12-year time series (2000 to 2011) with an 8-day interval of a 30 m spatial resolution data was generated by the use of

  19. A 30 ps Timing Resolution for Single Photons with Multi-pixel Burle MCP-PMT

    Energy Technology Data Exchange (ETDEWEB)

    Va' vra, J.; Benitez, J.; Coleman, J.; Leith, D.W.G.S.; Mazaheri, G.; Ratcliff, B.; Schwiening, J.; /SLAC

    2006-07-05

    We have achieved {approx}30 psec single-photoelectron and {approx}12ps for multi-photoelectron timing resolution with a new 64 pixel Burle MCP-PMT with 10 micron microchannel holes. We have also demonstrated that this detector works in a magnetic field of 15kG, and achieved a single-photoelectron timing resolution of better than 60 psec. The study is relevant for a new focusing DIRC RICH detector for particle identification at future Colliders such as the super B-factory or ILC, and for future TOF techniques. This study shows that a highly pixilated MCP-PMT can deliver excellent timing resolution.

  20. 0.5 ns resolution, 8-bit time-to-digital converter with flash ADC

    International Nuclear Information System (INIS)

    Sobczynski, C.

    1987-01-01

    A two-channel time-to-digital converter based on an 8-bit flash ADC is presented. The full scale time range of 127.5 ns is digitized to 8 bits providing 500 ps time resolution. The conversion time per channel is less than 800 ns. The design is foreseen to be implemented into Fastbus. (orig.)

  1. High resolution distributed time-to-digital converter (TDC) in a White Rabbit network

    International Nuclear Information System (INIS)

    Pan, Weibin; Gong, Guanghua; Du, Qiang; Li, Hongming; Li, Jianmin

    2014-01-01

    The Large High Altitude Air Shower Observatory (LHAASO) project consists of a complex detector array with over 6000 detector nodes spreading over 1.2 km 2 areas. The arrival times of shower particles are captured by time-to-digital converters (TDCs) in the detectors' frontend electronics, the arrival direction of the high energy cosmic ray are then to be reconstructed from the space-time information of all detector nodes. To guarantee the angular resolution of 0.5°, a time synchronization of 500 ps (RMS) accuracy and 100 ps precision must be achieved among all TDC nodes. A technology enhancing Gigabit Ethernet, called the White Rabbit (WR), has shown the capability of delivering sub-nanosecond accuracy and picoseconds precision of synchronization over the standard data packet transfer. In this paper we demonstrate a distributed TDC prototype system combining the FPGA based TDC and the WR technology. With the time synchronization and data transfer services from a compact WR node, separate FPGA-TDC nodes can be combined to provide uniform time measurement information for correlated events. The design detail and test performance will be described in the paper

  2. Measurement and simulation of the inelastic resolution function of a time-of-flight spectrometer

    International Nuclear Information System (INIS)

    Roth, S.V.; Zirkel, A.; Neuhaus, J.; Petry, W.; Bossy, J.; Peters, J.; Schober, H.

    2002-01-01

    The deconvolution of inelastic neutron scattering data requires the knowledge of the inelastic resolution function. The inelastic resolution function of the time-of-flight spectrometer IN5/ILL has been measured by exploiting the sharp resonances of the roton and maxon excitations in superfluid 4 He for the two respective (q,ω) values. The calculated inelastic resolution function for three different instrumental setups is compared to the experimentally determined resolution function. The agreement between simulation and experimental data is excellent, allowing us in principle to extrapolate the simulations and thus to determine the resolution function in the whole accessible dynamic range of IN5 or any other time-of-flight spectrometer. (orig.)

  3. Measurement and simulation of the inelastic resolution function of a time-of-flight spectrometer

    CERN Document Server

    Roth, S V; Neuhaus, J; Petry, W; Bossy, J; Peters, J; Schober, H

    2002-01-01

    The deconvolution of inelastic neutron scattering data requires the knowledge of the inelastic resolution function. The inelastic resolution function of the time-of-flight spectrometer IN5/ILL has been measured by exploiting the sharp resonances of the roton and maxon excitations in superfluid sup 4 He for the two respective (q,omega) values. The calculated inelastic resolution function for three different instrumental setups is compared to the experimentally determined resolution function. The agreement between simulation and experimental data is excellent, allowing us in principle to extrapolate the simulations and thus to determine the resolution function in the whole accessible dynamic range of IN5 or any other time-of-flight spectrometer. (orig.)

  4. Analysis of single-photon time resolution of FBK silicon photomultipliers

    International Nuclear Information System (INIS)

    Acerbi, Fabio; Ferri, Alessandro; Gola, Alberto; Zorzi, Nicola; Piemonte, Claudio

    2015-01-01

    We characterized and analyzed an important feature of silicon photomultipliers: the single-photon time resolution (SPTR). We characterized the SPTR of new RGB (Red–Green–Blue) type Silicon Photomultipliers and SPADs produced at FBK (Trento, Italy), studying its main limiting factors. We compared time resolution of 1×1 mm 2 and 3×3 mm 2 SiPMs and a single SiPM cell (i.e. a SPAD with integrated passive-quenching), employing a mode-locked pulsed laser with 2-ps wide pulses. We estimated the contribution of front-end electronic-noise, of cell-to-cell uniformity, and intrinsic cell time-resolution. At a single-cell level, we compared the results obtained with different layouts. With a circular cell with a top metallization covering part of the edge and enhancing the signal extraction, we reached ~20 ps FWHM of time resolution

  5. Analysis of single-photon time resolution of FBK silicon photomultipliers

    Energy Technology Data Exchange (ETDEWEB)

    Acerbi, Fabio, E-mail: acerbi@fbk.eu; Ferri, Alessandro; Gola, Alberto; Zorzi, Nicola; Piemonte, Claudio

    2015-07-01

    We characterized and analyzed an important feature of silicon photomultipliers: the single-photon time resolution (SPTR). We characterized the SPTR of new RGB (Red–Green–Blue) type Silicon Photomultipliers and SPADs produced at FBK (Trento, Italy), studying its main limiting factors. We compared time resolution of 1×1 mm{sup 2} and 3×3 mm{sup 2} SiPMs and a single SiPM cell (i.e. a SPAD with integrated passive-quenching), employing a mode-locked pulsed laser with 2-ps wide pulses. We estimated the contribution of front-end electronic-noise, of cell-to-cell uniformity, and intrinsic cell time-resolution. At a single-cell level, we compared the results obtained with different layouts. With a circular cell with a top metallization covering part of the edge and enhancing the signal extraction, we reached ~20 ps FWHM of time resolution.

  6. Deep Learning for Super-Resolution of Time Series Satellite Images

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to use deep learning techniques to enhance the spatial resolution of time series satellite images. This improvement, also called “super-resolution” is...

  7. Analytical model of SiPM time resolution and order statistics with crosstalk

    Energy Technology Data Exchange (ETDEWEB)

    Vinogradov, S., E-mail: Sergey.Vinogradov@liverpool.ac.uk [University of Liverpool and Cockcroft Institute, Sci-Tech Daresbury, Keckwick Lane, Warrington WA4 4AD (United Kingdom); P.N. Lebedev Physical Institute of the Russian Academy of Sciences, 119991 Leninskiy Prospekt 53, Moscow (Russian Federation)

    2015-07-01

    Time resolution is the most important parameter of photon detectors in a wide range of time-of-flight and time correlation applications within the areas of high energy physics, medical imaging, and others. Silicon photomultipliers (SiPM) have been initially recognized as perfect photon-number-resolving detectors; now they also provide outstanding results in the scintillator timing resolution. However, crosstalk and afterpulsing introduce false secondary non-Poissonian events, and SiPM time resolution models are experiencing significant difficulties with that. This study presents an attempt to develop an analytical model of the timing resolution of an SiPM taking into account statistics of secondary events resulting from a crosstalk. Two approaches have been utilized to derive an analytical expression for time resolution: the first one based on statistics of independent identically distributed detection event times and the second one based on order statistics of these times. The first approach is found to be more straightforward and “analytical-friendly” to model analog SiPMs. Comparisons of coincidence resolving times predicted by the model with the known experimental results from a LYSO:Ce scintillator and a Hamamatsu MPPC are presented.

  8. Analytical model of SiPM time resolution and order statistics with crosstalk

    International Nuclear Information System (INIS)

    Vinogradov, S.

    2015-01-01

    Time resolution is the most important parameter of photon detectors in a wide range of time-of-flight and time correlation applications within the areas of high energy physics, medical imaging, and others. Silicon photomultipliers (SiPM) have been initially recognized as perfect photon-number-resolving detectors; now they also provide outstanding results in the scintillator timing resolution. However, crosstalk and afterpulsing introduce false secondary non-Poissonian events, and SiPM time resolution models are experiencing significant difficulties with that. This study presents an attempt to develop an analytical model of the timing resolution of an SiPM taking into account statistics of secondary events resulting from a crosstalk. Two approaches have been utilized to derive an analytical expression for time resolution: the first one based on statistics of independent identically distributed detection event times and the second one based on order statistics of these times. The first approach is found to be more straightforward and “analytical-friendly” to model analog SiPMs. Comparisons of coincidence resolving times predicted by the model with the known experimental results from a LYSO:Ce scintillator and a Hamamatsu MPPC are presented

  9. Estuarine modeling: Does a higher grid resolution improve model performance?

    Science.gov (United States)

    Ecological models are useful tools to explore cause effect relationships, test hypothesis and perform management scenarios. A mathematical model, the Gulf of Mexico Dissolved Oxygen Model (GoMDOM), has been developed and applied to the Louisiana continental shelf of the northern ...

  10. ATLAS Tile Calorimeter time calibration, monitoring and performance

    CERN Document Server

    Davidek, Tomas; The ATLAS collaboration

    2016-01-01

    The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the central region of the ATLAS experiment at the LHC. This sampling device is made of plastic scintillating tiles alternated with iron plates and its response is calibrated to electromagnetic scale by means of several dedicated calibration systems. The accurate time calibration is important for the energy reconstruction, non-collision background removal as well as for specific physics analyses. The initial time calibration with so-called splash events and subsequent fine-tuning with collision data are presented. The monitoring of the time calibration with laser system and physics collision data is discussed as well as the corrections for sudden changes performed still before the recorded data are processed for physics analyses. Finally, the time resolution as measured with jets and isolated muons particles is presented.

  11. Improvements in the energy resolution and high-count-rate performance of bismuth germanate

    International Nuclear Information System (INIS)

    Koehler, P.E.; Wender, S.A.; Kapustinsky, J.S.

    1985-01-01

    Several methods for improving the energy resolution of bismuth germanate (BGO) have been investigated. It is shown that some of these methods resulted in a substantial improvement in the energy resolution. In addition, a method to improve the performance of BGO at high counting rates has been systematically studied. The results of this study are presented and discussed

  12. High-resolution real-time sonography and MR imaging in assessment of osteocartilaginous exostoses

    International Nuclear Information System (INIS)

    Prayer, L.M.; Kropej, D.H.; Wimberger, D.M.; Wurnig, C.F.; Kramer, J.; Kainberger, F.M.; Braun, O.H.; Ritschl, P.W.; Imhof, H.

    1991-01-01

    High-resolution real-time ultrasonography (US) and MR imaging, using both spin-echo (SE) and gradient-echo (GE) sequences, were performed prospectively in 14 patients with solitary osteocartilaginous exostoses to assess cartilage cap thickness and bursa formation. Results were compared to surgical and histopathologic findings in all cases. Both US and MR imaging were useful in evaluating exostotic cartilage cap thickness, which is supposed to be the most reliable sign of malignant transformation. Hyaline cartilage matrix had distinctive features in US and MR imaging caused by its specific histologic composition. The formation of bursae over the protruding exostoses, which results in pain and clinically could raise the suspicion of growth and malignant transformation, was demonstrated best using GE sequences. MR imaging was thus superior to US in the detection of bursa formation. (orig.)

  13. Performance comparison of various time variant filters

    Energy Technology Data Exchange (ETDEWEB)

    Kuwata, M. [JEOL Engineering Co. Ltd., Akishima, Tokyo (Japan); Husimi, K.

    1996-07-01

    This paper describes the advantage of the trapezoidal filter used in semiconductor detector system comparing with the other time variant filters. The trapezoidal filter is the compose of a rectangular pre-filter and a gated integrator. We indicate that the best performance is obtained by the differential-integral summing type rectangular pre-filter. This filter is not only superior in performance, but also has the useful feature that the rising edge of the output waveform is linear. We introduce an example of this feature used in a high-energy experiment. (author)

  14. A high-resolution mini-microscope system for wireless real-time monitoring.

    Science.gov (United States)

    Wang, Zongjie; Boddeda, Akash; Parker, Benjamin; Samanipour, Roya; Ghosh, Sanjoy; Menard, Frederic; Kim, Keekyoung

    2017-09-04

    Compact, cost-effective and high-performance microscope that enables the real-time imaging of cells and lab-on-a-chip devices is highly demanded for cell biology and biomedical engineering. This paper aims to present the design and application of an inexpensive wireless mini-microscope with resolution up to 2592 × 1944 pixels and speed up to 90 fps. The mini-microscope system was built on a commercial embedded system (Raspberry Pi). We modified a camera module and adopted an inverse dual lens system to obtain the clear field of view and appropriate magnification for tens of micrometer objects. The system was capable of capturing time-lapse images and transferring image data wirelessly. The entire system can be operated wirelessly and cordlessly in a conventional cell culturing incubator. The developed mini-microscope was used to monitor the attachment and proliferation of NIH-3T3 and HEK 293 cells inside an incubator for 50 hours. In addition, the mini-microscope was used to monitor a droplet generation process in a microfluidic device. The high-quality images captured by the mini-microscope enabled us an automated analysis of experimental parameters. The successful applications prove the great potential of the developed mini-microscope for monitoring various biological samples and microfluidic devices. This paper presents the design of a high resolution mini-microscope system that enables the wireless real-time imaging of cells inside the incubator. This system has been verified to be a useful tool to obtain high-quality images and videos for the automated quantitative analysis of biological samples and lab-on-a-chip devices in the long term.

  15. Small angle neutron scattering at very high time resolution: Principle and simulations of 'TISANE'

    International Nuclear Information System (INIS)

    Kipping, D.; Gaehler, R.; Habicht, K.

    2008-01-01

    The time resolution of SANS experiments is generally limited by frame overlap to some ms. We report on a new time-resolved stroboscopic SANS method, called TISANE, offering μs time resolution without a major sacrifice in intensity by making use of very large frame overlap. We may explore a new field in neutron scattering and complement the emerging field of time resolved small angle X-ray scattering. Here we discuss the principle of TISANE, its mathematical treatment and its limitations

  16. Wide-range time-to-digital converters with a high resolution

    International Nuclear Information System (INIS)

    Aul'chenko, V.M.

    1977-01-01

    A combined time-number converter in which measurements of time intervals to within a period of clock frequency are made directly and those within a period are by a time-amplitude-code conversion is described. It allows time intervals up to 4 mcsec with a resolution of 100 psec to be measured. The differential nonlinearity of conversion is not greater than +-1.5%, and the integral error from measurements of time intervals is not greater than +-100 psec

  17. Performance of High Resolution Satellite Rainfall Products over Data Scarce Parts of Eastern Ethiopia

    Directory of Open Access Journals (Sweden)

    Shimelis B. Gebere

    2015-09-01

    Full Text Available Accurate estimation of rainfall in mountainous areas is necessary for various water resource-related applications. Though rain gauges accurately measure rainfall, they are rarely found in mountainous regions and satellite rainfall data can be used as an alternative source over these regions. This study evaluated the performance of three high-resolution satellite rainfall products, the Tropical Rainfall Measuring Mission (TRMM 3B42, the Global Satellite Mapping of Precipitation (GSMaP_MVK+, and the Precipitation Estimation from Remotely-Sensed Information using Artificial Neural Networks (PERSIANN at daily, monthly, and seasonal time scales against rain gauge records over data-scarce parts of Eastern Ethiopia. TRMM 3B42 rain products show relatively better performance at the three time scales, while PERSIANN did much better than GSMaP. At the daily time scale, TRMM correctly detected 88% of the rainfall from the rain gauge. The correlation at the monthly time scale also revealed that the TRMM has captured the observed rainfall better than the other two. For Belg (short rain and Kiremt (long rain seasons, the TRMM did better than the others by far. However, during Bega (dry season, PERSIANN showed a relatively good estimate. At all-time scales, noticing the bias, TRMM tends to overestimate, while PERSIANN and GSMaP tend to underestimate the rainfall. The overall result suggests that monthly and seasonal TRMM rainfall performed better than daily rainfall. It has also been found that both GSMaP and PERSIANN performed better in relatively flat areas than mountainous areas. Before the practical use of TRMM, the RMSE value needs to be improved by considering the topography of the study area or adjusting the bias.

  18. A comprehensive & systematic study of coincidence time resolution and light yield using scintillators of different size, wrapping and doping

    CERN Document Server

    Auffray, E.; Geraci, F.; Ghezzi, A.; Gundacker, S.; Hillemanns, H.; Jarron, P.; Meyer, T.; Paganoni, M.; Pauwels, K.; Pizzichemi, M.; Lecoq, P.

    2011-01-01

    Over the last years interest in using time-of-flight-based Positron Emission Tomography (TOF-PET) systems has significantly increased. High time resolution in such PET systems is a powerful tool to improve signal to noise ratio and therefore to allow smaller exposure rates for patients as well as faster image reconstruction. Improvement in coincidence time resolution (CTR) in PET systems to the level of 200ps FWHM requires the optimization of all parameters in the photon detection chain influencing the time resolution: crystal, photodetector and readout electronics. After reviewing the factors influencing the time resolution of scintillators, we will present in this paper the light yield and CTR obtained for different scintillator types (LSO:Ce, LYSO:Ce, LGSO:Ce, LSO:Ce:0.4Ca, LuAG:Ce, LuAG:Pr) with different cross-sections, lengths and reflectors. Whereas light yield measurements were made with a classical PMT, all CTR tests were performed with Hamamatsu-MPPCs or SiPMs S10931-050P. The CTR measurements were ...

  19. Development of high speed integrated circuit for very high resolution timing measurements

    International Nuclear Information System (INIS)

    Mester, Christian

    2009-10-01

    A multi-channel high-precision low-power time-to-digital converter application specific integrated circuit for high energy physics applications has been designed and implemented in a 130 nm CMOS process. To reach a target resolution of 24.4 ps, a novel delay element has been conceived. This nominal resolution has been experimentally verified with a prototype, with a minimum resolution of 19 ps. To further improve the resolution, a new interpolation scheme has been described. The ASIC has been designed to use a reference clock with the LHC bunch crossing frequency of 40 MHz and generate all required timing signals internally, to ease to use within the framework of an LHC upgrade. Special care has been taken to minimise the power consumption. (orig.)

  20. Development of high speed integrated circuit for very high resolution timing measurements

    Energy Technology Data Exchange (ETDEWEB)

    Mester, Christian

    2009-10-15

    A multi-channel high-precision low-power time-to-digital converter application specific integrated circuit for high energy physics applications has been designed and implemented in a 130 nm CMOS process. To reach a target resolution of 24.4 ps, a novel delay element has been conceived. This nominal resolution has been experimentally verified with a prototype, with a minimum resolution of 19 ps. To further improve the resolution, a new interpolation scheme has been described. The ASIC has been designed to use a reference clock with the LHC bunch crossing frequency of 40 MHz and generate all required timing signals internally, to ease to use within the framework of an LHC upgrade. Special care has been taken to minimise the power consumption. (orig.)

  1. A new high resolution time-of-flight mass spectrometer with gridless reflector

    International Nuclear Information System (INIS)

    Bhowmick, A.; Korgaonkar, A.V.; Carvalho, W.C.J.; Yakhmi, J.V.; Sahni, V.C.

    2004-01-01

    High resolution in time-of-flight mass spectrometers essentially depends upon the capacity of the machine to control the initial spatial and energy distributions of the ions from the source or of any particular ionization process. In the present scenario, high resolution time-of-flight mass spectrometers are becoming more and more essential for rapid mass analysis of fairly large molecules or species e.g. large biomolecules, proteins, drugs, atomic clusters, etc. Simple mass measurements of atomic clusters have revealed major fundamental information about their electronic and geometric structures. Newer designs of time-of-flight mass spectrometers have high resolution, adaptability to multiple ionization techniques, high sensitivity, capability of addressing comparatively slower physical events etc. are, therefore, being reported regularly. A newly developed time-of-flight mass spectrometer is described

  2. Progress, Performance, and Prospects of Ultra-High Resolution Microcalorimeter Spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Hoover, Andrew Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bennett, D. A. [National Inst. of Standards and Technology (NIST), Boulder, CO (United States); Croce, Mark Philip [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rabin, Michael W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ullom, J. N. [National Inst. of Standards and Technology (NIST), Boulder, CO (United States); Univ. of Colorado, Boulder, CO (United States)

    2017-01-23

    In 2005 the LANL/NIST team used a single high-resolution microcalorimeter detector to measure the gamma-ray spectrum of a plutonium sample. After more than a decade of research and development on this topic, both the technology and our general understanding of its capabilities have advanced greatly, such that a progress review is now timely. We examine the scenario of a large-scale reprocessing plant and conclude that current non-destructive analysis (NDA) methods are inadequate to safeguard such a facility to the desired levels, leading to undesirable dependence on massspectrometry (MS) destructive analysis (DA). The development of microcalorimeter detectors is intended to close the performance gap between NDA and DA methods to address the needs of nuclear facilities.

  3. Real-time cardiovascular magnetic resonance at high temporal resolution: radial FLASH with nonlinear inverse reconstruction

    Directory of Open Access Journals (Sweden)

    Merboldt Klaus-Dietmar

    2010-07-01

    Full Text Available Abstract Background Functional assessments of the heart by dynamic cardiovascular magnetic resonance (CMR commonly rely on (i electrocardiographic (ECG gating yielding pseudo real-time cine representations, (ii balanced gradient-echo sequences referred to as steady-state free precession (SSFP, and (iii breath holding or respiratory gating. Problems may therefore be due to the need for a robust ECG signal, the occurrence of arrhythmia and beat to beat variations, technical instabilities (e.g., SSFP "banding" artefacts, and limited patient compliance and comfort. Here we describe a new approach providing true real-time CMR with image acquisition times as short as 20 to 30 ms or rates of 30 to 50 frames per second. Methods The approach relies on a previously developed real-time MR method, which combines a strongly undersampled radial FLASH CMR sequence with image reconstruction by regularized nonlinear inversion. While iterative reconstructions are currently performed offline due to limited computer speed, online monitoring during scanning is accomplished using gridding reconstructions with a sliding window at the same frame rate but with lower image quality. Results Scans of healthy young subjects were performed at 3 T without ECG gating and during free breathing. The resulting images yield T1 contrast (depending on flip angle with an opposed-phase or in-phase condition for water and fat signals (depending on echo time. They completely avoid (i susceptibility-induced artefacts due to the very short echo times, (ii radiofrequency power limitations due to excitations with flip angles of 10° or less, and (iii the risk of peripheral nerve stimulation due to the use of normal gradient switching modes. For a section thickness of 8 mm, real-time images offer a spatial resolution and total acquisition time of 1.5 mm at 30 ms and 2.0 mm at 22 ms, respectively. Conclusions Though awaiting thorough clinical evaluation, this work describes a robust and

  4. Improved Resolution Optical Time Stretch Imaging Based on High Efficiency In-Fiber Diffraction.

    Science.gov (United States)

    Wang, Guoqing; Yan, Zhijun; Yang, Lei; Zhang, Lin; Wang, Chao

    2018-01-12

    Most overlooked challenges in ultrafast optical time stretch imaging (OTSI) are sacrificed spatial resolution and higher optical loss. These challenges are originated from optical diffraction devices used in OTSI, which encode image into spectra of ultrashort optical pulses. Conventional free-space diffraction gratings, as widely used in existing OTSI systems, suffer from several inherent drawbacks: limited diffraction efficiency in a non-Littrow configuration due to inherent zeroth-order reflection, high coupling loss between free-space gratings and optical fibers, bulky footprint, and more importantly, sacrificed imaging resolution due to non-full-aperture illumination for individual wavelengths. Here we report resolution-improved and diffraction-efficient OTSI using in-fiber diffraction for the first time to our knowledge. The key to overcome the existing challenges is a 45° tilted fiber grating (TFG), which serves as a compact in-fiber diffraction device offering improved diffraction efficiency (up to 97%), inherent compatibility with optical fibers, and improved imaging resolution owning to almost full-aperture illumination for all illumination wavelengths. 50 million frames per second imaging of fast moving object at 46 m/s with improved imaging resolution has been demonstrated. This conceptually new in-fiber diffraction design opens the way towards cost-effective, compact and high-resolution OTSI systems for image-based high-throughput detection and measurement.

  5. Performance of a high-resolution depth-encoding PET detector module using linearly-graded SiPM arrays

    Science.gov (United States)

    Du, Junwei; Bai, Xiaowei; Gola, Alberto; Acerbi, Fabio; Ferri, Alessandro; Piemonte, Claudio; Yang, Yongfeng; Cherry, Simon R.

    2018-02-01

    The goal of this study was to exploit the excellent spatial resolution characteristics of a position-sensitive silicon photomultiplier (SiPM) and develop a high-resolution depth-of-interaction (DOI) encoding positron emission tomography (PET) detector module. The detector consists of a 30  ×  30 array of 0.445  ×  0.445  ×  20 mm3 polished LYSO crystals coupled to two 15.5  ×  15.5 mm2 linearly-graded SiPM (LG-SiPM) arrays at both ends. The flood histograms show that all the crystals in the LYSO array can be resolved. The energy resolution, the coincidence timing resolution and the DOI resolution were 21.8  ±  5.8%, 1.23  ±  0.10 ns and 3.8  ±  1.2 mm, respectively, at a temperature of ‑10 °C and a bias voltage of 35.0 V. The performance did not degrade significantly for event rates of up to 130 000 counts s‑1. This detector represents an attractive option for small-bore PET scanner designs that simultaneously emphasize high spatial resolution and high detection efficiency, important, for example, in preclinical imaging of the rodent brain with neuroreceptor ligands.

  6. Performance of a high-resolution depth-encoding PET detector module using linearly-graded SiPM arrays.

    Science.gov (United States)

    Du, Junwei; Bai, Xiaowei; Gola, Alberto; Acerbi, Fabio; Ferri, Alessandro; Piemonte, Claudio; Yang, Yongfeng; Cherry, Simon R

    2018-02-05

    The goal of this study was to exploit the excellent spatial resolution characteristics of a position-sensitive silicon photomultiplier (SiPM) and develop a high-resolution depth-of-interaction (DOI) encoding positron emission tomography (PET) detector module. The detector consists of a 30  ×  30 array of 0.445  ×  0.445  ×  20 mm 3 polished LYSO crystals coupled to two 15.5  ×  15.5 mm 2 linearly-graded SiPM (LG-SiPM) arrays at both ends. The flood histograms show that all the crystals in the LYSO array can be resolved. The energy resolution, the coincidence timing resolution and the DOI resolution were 21.8  ±  5.8%, 1.23  ±  0.10 ns and 3.8  ±  1.2 mm, respectively, at a temperature of -10 °C and a bias voltage of 35.0 V. The performance did not degrade significantly for event rates of up to 130 000 counts s -1 . This detector represents an attractive option for small-bore PET scanner designs that simultaneously emphasize high spatial resolution and high detection efficiency, important, for example, in preclinical imaging of the rodent brain with neuroreceptor ligands.

  7. Sharp or broad pulse peak for high resolution instruments? Choice of moderator performance

    International Nuclear Information System (INIS)

    Arai, M.; Watanabe, N.; Teshigawara, M.

    2001-01-01

    We demonstrate a concept how we should choose moderator performance to realize required performance for instruments. Neutron burst pulse can be characterized with peak intensity, peak width and tail. Those can be controllable by designing moderator, i.e. material, temperature, shape, decoupling, poisoning and having premoderator. Hence there are large number of variable parameters to be determined. Here we discuss the required moderator performance for some typical examples, i.e. high resolution powder instrument, chopper instrument, high resolution back scattering machine. (author)

  8. Monthly Rainfall Erosivity: Conversion Factors for Different Time Resolutions and Regional Assessments

    DEFF Research Database (Denmark)

    Panagos, Panos; Borrelli, Pasquale; Spinoni, Jonathan

    2016-01-01

    , for the optimization of land management (seasonal variation of vegetation cover and agricultural support practices) as well as natural hazard protection (landslides and flood prediction). We expanded REDES by 140 rainfall stations, thus covering areas where monthly R-factor values were missing (Slovakia, Poland......) or former data density was not satisfactory (Austria, France, and Spain). The different time resolutions (from 5 to 60 min) of high temporal data require a conversion of monthly R-factor based on a pool of stations with available data at all time resolutions. Because the conversion factors show smaller...

  9. Calculation of the time resolution of the J-PET tomograph using kernel density estimation

    Science.gov (United States)

    Raczyński, L.; Wiślicki, W.; Krzemień, W.; Kowalski, P.; Alfs, D.; Bednarski, T.; Białas, P.; Curceanu, C.; Czerwiński, E.; Dulski, K.; Gajos, A.; Głowacz, B.; Gorgol, M.; Hiesmayr, B.; Jasińska, B.; Kamińska, D.; Korcyl, G.; Kozik, T.; Krawczyk, N.; Kubicz, E.; Mohammed, M.; Pawlik-Niedźwiecka, M.; Niedźwiecki, S.; Pałka, M.; Rudy, Z.; Rundel, O.; Sharma, N. G.; Silarski, M.; Smyrski, J.; Strzelecki, A.; Wieczorek, A.; Zgardzińska, B.; Zieliński, M.; Moskal, P.

    2017-06-01

    In this paper we estimate the time resolution of the J-PET scanner built from plastic scintillators. We incorporate the method of signal processing using the Tikhonov regularization framework and the kernel density estimation method. We obtain simple, closed-form analytical formulae for time resolution. The proposed method is validated using signals registered by means of the single detection unit of the J-PET tomograph built from a 30 cm long plastic scintillator strip. It is shown that the experimental and theoretical results obtained for the J-PET scanner equipped with vacuum tube photomultipliers are consistent.

  10. High-resolution near real-time drought monitoring in South Asia

    OpenAIRE

    Aadhar, Saran; Mishra, Vimal

    2017-01-01

    Drought in South Asia affect food and water security and pose challenges for millions of people. For policy-making, planning, and management of water resources at sub-basin or administrative levels, high-resolution datasets of precipitation and air temperature are required in near-real time. We develop a high-resolution (0.05°) bias-corrected precipitation and temperature data that can be used to monitor near real-time drought conditions over South Asia. Moreover, the dataset can be used to m...

  11. Measurement of the time resolution of small SiPM-based scintillation counters

    Science.gov (United States)

    Kravchenko, E. A.; Porosev, V. V.; Savinov, G. A.

    2017-12-01

    In this research, we evaluated the timing resolution of SiPM-based scintillation detector on a 1-GeV electron beam "extracted" from VEPP-4M. We tested small scintillation crystals of pure CsI, YAP, LYSO, and LFS-3 with HAMAMATSU S10362-33-025C and S13360-3050CS. The CsI scintillator together with HAMAMATSU S13360-3050CS demonstrated the best results. Nevertheless, the achieved time resolution of ~80 ps (RMS) relates mainly to the photodetector itself. It makes the silicon photomultiplier an attractive candidate to replace other devices in applications where sub-nanosecond accuracy is required.

  12. Real-time analysis and visualization for single-molecule based super-resolution microscopy.

    Directory of Open Access Journals (Sweden)

    Adel Kechkar

    Full Text Available Accurate multidimensional localization of isolated fluorescent emitters is a time consuming process in single-molecule based super-resolution microscopy. We demonstrate a functional method for real-time reconstruction with automatic feedback control, without compromising the localization accuracy. Compatible with high frame rates of EM-CCD cameras, it relies on a wavelet segmentation algorithm, together with a mix of CPU/GPU implementation. A combination with Gaussian fitting allows direct access to 3D localization. Automatic feedback control ensures optimal molecule density throughout the acquisition process. With this method, we significantly improve the efficiency and feasibility of localization-based super-resolution microscopy.

  13. High-resolution and super stacking of time-reversal mirrors in locating seismic sources

    KAUST Repository

    Cao, Weiping

    2011-07-08

    Time reversal mirrors can be used to backpropagate and refocus incident wavefields to their actual source location, with the subsequent benefits of imaging with high-resolution and super-stacking properties. These benefits of time reversal mirrors have been previously verified with computer simulations and laboratory experiments but not with exploration-scale seismic data. We now demonstrate the high-resolution and the super-stacking properties in locating seismic sources with field seismic data that include multiple scattering. Tests on both synthetic data and field data show that a time reversal mirror has the potential to exceed the Rayleigh resolution limit by factors of 4 or more. Results also show that a time reversal mirror has a significant resilience to strong Gaussian noise and that accurate imaging of source locations from passive seismic data can be accomplished with traces having signal-to-noise ratios as low as 0.001. Synthetic tests also demonstrate that time reversal mirrors can sometimes enhance the signal by a factor proportional to the square root of the product of the number of traces, denoted as N and the number of events in the traces. This enhancement property is denoted as super-stacking and greatly exceeds the classical signal-to-noise enhancement factor of. High-resolution and super-stacking are properties also enjoyed by seismic interferometry and reverse-time migration with the exact velocity model. © 2011 European Association of Geoscientists & Engineers.

  14. A high time resolution x-ray diagnostic on the Madison Symmetric Torus

    Science.gov (United States)

    DuBois, Ami M.; Lee, John David; Almagri, Abdulgadar F.

    2015-07-01

    A new high time resolution x-ray detector has been installed on the Madison Symmetric Torus (MST) to make measurements around sawtooth events. The detector system is comprised of a silicon avalanche photodiode, a 20 ns Gaussian shaping amplifier, and a 500 MHz digitizer with 14-bit sampling resolution. The fast shaping time diminishes the need to restrict the amount of x-ray flux reaching the detector, limiting the system dead-time. With a much higher time resolution than systems currently in use in high temperature plasma physics experiments, this new detector has the versatility to be used in a variety of discharges with varying flux and the ability to study dynamics on both slow and fast time scales. This paper discusses the new fast x-ray detector recently installed on MST and the improved time resolution capabilities compared to the existing soft and hard x-ray diagnostics. In addition to the detector hardware, improvements to the detector calibration and x-ray pulse identification software, such as additional fitting parameters and a more sophisticated fitting routine are discussed. Finally, initial data taken in both high confinement and standard reversed-field pinch plasma discharges are compared.

  15. All-passive pixel super-resolution of time-stretch imaging

    Science.gov (United States)

    Chan, Antony C. S.; Ng, Ho-Cheung; Bogaraju, Sharat C. V.; So, Hayden K. H.; Lam, Edmund Y.; Tsia, Kevin K.

    2017-03-01

    Based on image encoding in a serial-temporal format, optical time-stretch imaging entails a stringent requirement of state-of-the-art fast data acquisition unit in order to preserve high image resolution at an ultrahigh frame rate — hampering the widespread utilities of such technology. Here, we propose a pixel super-resolution (pixel-SR) technique tailored for time-stretch imaging that preserves pixel resolution at a relaxed sampling rate. It harnesses the subpixel shifts between image frames inherently introduced by asynchronous digital sampling of the continuous time-stretch imaging process. Precise pixel registration is thus accomplished without any active opto-mechanical subpixel-shift control or other additional hardware. Here, we present the experimental pixel-SR image reconstruction pipeline that restores high-resolution time-stretch images of microparticles and biological cells (phytoplankton) at a relaxed sampling rate (≈2-5 GSa/s)—more than four times lower than the originally required readout rate (20 GSa/s) — is thus effective for high-throughput label-free, morphology-based cellular classification down to single-cell precision. Upon integration with the high-throughput image processing technology, this pixel-SR time-stretch imaging technique represents a cost-effective and practical solution for large scale cell-based phenotypic screening in biomedical diagnosis and machine vision for quality control in manufacturing.

  16. Photonics-based broadband radar for high-resolution and real-time inverse synthetic aperture imaging.

    Science.gov (United States)

    Zhang, Fangzheng; Guo, Qingshui; Wang, Ziqian; Zhou, Pei; Zhang, Guoqiang; Sun, Jun; Pan, Shilong

    2017-07-10

    A photonics-based radar with generation and de-chirp processing of broadband linear frequency modulated continuous-wave (LFMCW) signal in optical domain is proposed for high-resolution and real-time inverse synthetic aperture radar (ISAR) imaging. In the proposed system, a broadband LFMCW signal is generated by a photonic frequency quadrupler based on a single integrated electro-optical modulator, and the echoes reflected from the targets are de-chirped to a low frequency signal by a microwave photonic frequency mixer. The proposed radar can operate at a high frequency with a large bandwidth, and thus achieve an ultra-high range resolution for ISAR imaging. Thanks to the wideband photonic de-chirp technique, the radar receiver could apply low-speed analog-to-digital conversion and mature digital signal processing, which makes real-time ISAR imaging possible. A K-band photonics-based radar with an instantaneous bandwidth of 8 GHz (18-26 GHz) is established and its performance for ISAR imaging is experimentally investigated. Results show that a recorded two-dimensional imaging resolution of ~2 cm × ~2 cm is achieved with a sampling rate of 100 MSa/s in the receiver. Besides, fast ISAR imaging with 100 frames per second is verified. The proposed radar is an effective solution to overcome the limitations on operation bandwidth and processing speed of current radar imaging technologies, which may enable applications where high-resolution and real-time radar imaging is required.

  17. Simulation studies for a high resolution time projection chamber at the international linear collider

    Energy Technology Data Exchange (ETDEWEB)

    Muennich, A.

    2007-03-26

    The International Linear Collider (ILC) is planned to be the next large accelerator. The ILC will be able to perform high precision measurements only possible at the clean environment of electron positron collisions. In order to reach this high accuracy, the requirements for the detector performance are challenging. Several detector concepts are currently under study. The understanding of the detector and its performance will be crucial to extract the desired physics results from the data. To optimise the detector design, simulation studies are needed. Simulation packages like GEANT4 allow to model the detector geometry and simulate the energy deposit in the different materials. However, the detector response taking into account the transportation of the produced charge to the readout devices and the effects ofthe readout electronics cannot be described in detail. These processes in the detector will change the measured position of the energy deposit relative to the point of origin. The determination of this detector response is the task of detailed simulation studies, which have to be carried out for each subdetector. A high resolution Time Projection Chamber (TPC) with gas amplification based on micro pattern gas detectors, is one of the options for the main tracking system at the ILC. In the present thesis a detailed simulation tool to study the performance of a TPC was developed. Its goal is to find the optimal settings to reach an excellent momentum and spatial resolution. After an introduction to the present status of particle physics and the ILC project with special focus on the TPC as central tracker, the simulation framework is presented. The basic simulation methods and implemented processes are introduced. Within this stand-alone simulation framework each electron produced by primary ionisation is transferred through the gas volume and amplified using Gas Electron Multipliers (GEMs). The output format of the simulation is identical to the raw data from a

  18. Development of high time resolution measurement system of frequency characteristics in bioelectrical impedance for biodynamic analysis

    Science.gov (United States)

    Nakamura, Takao; Kusuhara, Toshimasa; Yamamoto, Yoshitake

    2006-11-01

    We have proposed biodynamic analysis using bioelectrical impedance at 50 kHz, which is measured with synchronous rectification method. In order to analyze impedance parameters in biodynamics, the measurement of frequency characteristics in bioelectrical impedance with a high time resolution are required. Therefore we have developed a high time resolution measurement system for bioelectrical impedance with 10 frequency points and time resolution of 1 ms. A voltage E A, which consisted of fundamental wave and 9 kinds of harmonic wave from 1 kHz to 1MHz, were converted to current. The current flowed through human body and a potential voltage, EV was detected in the measured part. After A/D conversion of EV and E A in the sampling frequency 2 MHz, data number 2048 points, the impedance were calculated using Fast Fourier Transform. The measured time 1.024 ms was the period of the fundamental wave and time resolution of this system. The specification is enough accuracy for measurement of bioelectrical impedance for biodynamic analysis.

  19. Performance of the operational high-resolution numerical weather predictions of the Daphne project

    Science.gov (United States)

    Tegoulias, Ioannis; Pytharoulis, Ioannis; Karacostas, Theodore; Kartsios, Stergios; Kotsopoulos, Stelios; Bampzelis, Dimitrios

    2015-04-01

    In the framework of the DAPHNE project, the Department of Meteorology and Climatology (http://meteo.geo.auth.gr) of the Aristotle University of Thessaloniki, Greece, utilizes the nonhydrostatic Weather Research and Forecasting model with the Advanced Research dynamic solver (WRF-ARW) in order to produce high-resolution weather forecasts over Thessaly in central Greece. The aim of the DAPHNE project is to tackle the problem of drought in this area by means of Weather Modification. Cloud seeding assists the convective clouds to produce rain more efficiently or reduce hailstone size in favour of raindrops. The most favourable conditions for such a weather modification program in Thessaly occur in the period from March to October when convective clouds are triggered more frequently. Three model domains, using 2-way telescoping nesting, cover: i) Europe, the Mediterranean sea and northern Africa (D01), ii) Greece (D02) and iii) the wider region of Thessaly (D03; at selected periods) at horizontal grid-spacings of 15km, 5km and 1km, respectively. This research work intents to describe the atmospheric model setup and analyse its performance during a selected period of the operational phase of the project. The statistical evaluation of the high-resolution operational forecasts is performed using surface observations, gridded fields and radar data. Well established point verification methods combined with novel object based upon these methods, provide in depth analysis of the model skill. Spatial characteristics are adequately captured but a variable time lag between forecast and observation is noted. Acknowledgments: This research work has been co-financed by the European Union (European Regional Development Fund) and Greek national funds, through the action "COOPERATION 2011: Partnerships of Production and Research Institutions in Focused Research and Technology Sectors" (contract number 11SYN_8_1088 - DAPHNE) in the framework of the operational programme "Competitiveness

  20. Time-resolved ARPES with sub-15 fs temporal and near Fourier-limited spectral resolution.

    Science.gov (United States)

    Rohde, G; Hendel, A; Stange, A; Hanff, K; Oloff, L-P; Yang, L X; Rossnagel, K; Bauer, M

    2016-10-01

    An experimental setup for time- and angle-resolved photoelectron spectroscopy with sub-15 fs temporal resolution is presented. A hollow-fiber compressor is used for the generation of 6.5 fs white light pump pulses, and a high-harmonic-generation source delivers 11 fs probe pulses at a photon energy of 22.1 eV. A value of 13 fs full width at half-maximum of the pump-probe cross correlation signal is determined by analyzing a photoemission intensity transient probing a near-infrared interband transition in 1T-TiSe 2 . Notably, the energy resolution of the setup conforms to typical values reported in conventional time-resolved photoemission studies using high harmonics, and an ultimate resolution of 170 meV is feasible.

  1. Tablet disintegration studied by high-resolution real-time magnetic resonance imaging.

    Science.gov (United States)

    Quodbach, Julian; Moussavi, Amir; Tammer, Roland; Frahm, Jens; Kleinebudde, Peter

    2014-01-01

    The present work employs recent advances in high-resolution real-time magnetic resonance imaging (MRI) to investigate the disintegration process of tablets containing disintegrants. A temporal resolution of 75 ms and a spatial resolution of 80 × 80 µm with a section thickness of only 600 µm were achieved. The histograms of MRI videos were quantitatively analyzed with MATLAB. The mechanisms of action of six commercially available disintegrants, the influence of relative tablet density, and the impact of disintegrant concentration were examined. Crospovidone seems to be the only disintegrant acting by a shape memory effect, whereas the others mainly swell. A higher relative density of tablets containing croscarmellose sodium leads to a more even distribution of water within the tablet matrix but hardly impacts the disintegration kinetics. Increasing the polacrilin potassium disintegrant concentration leads to a quicker and more thorough disintegration process. Real-time MRI emerges as valuable tool to visualize and investigate the process of tablet disintegration.

  2. Real-time Tsunami Inundation Prediction Using High Performance Computers

    Science.gov (United States)

    Oishi, Y.; Imamura, F.; Sugawara, D.

    2014-12-01

    Recently off-shore tsunami observation stations based on cabled ocean bottom pressure gauges are actively being deployed especially in Japan. These cabled systems are designed to provide real-time tsunami data before tsunamis reach coastlines for disaster mitigation purposes. To receive real benefits of these observations, real-time analysis techniques to make an effective use of these data are necessary. A representative study was made by Tsushima et al. (2009) that proposed a method to provide instant tsunami source prediction based on achieving tsunami waveform data. As time passes, the prediction is improved by using updated waveform data. After a tsunami source is predicted, tsunami waveforms are synthesized from pre-computed tsunami Green functions of linear long wave equations. Tsushima et al. (2014) updated the method by combining the tsunami waveform inversion with an instant inversion of coseismic crustal deformation and improved the prediction accuracy and speed in the early stages. For disaster mitigation purposes, real-time predictions of tsunami inundation are also important. In this study, we discuss the possibility of real-time tsunami inundation predictions, which require faster-than-real-time tsunami inundation simulation in addition to instant tsunami source analysis. Although the computational amount is large to solve non-linear shallow water equations for inundation predictions, it has become executable through the recent developments of high performance computing technologies. We conducted parallel computations of tsunami inundation and achieved 6.0 TFLOPS by using 19,000 CPU cores. We employed a leap-frog finite difference method with nested staggered grids of which resolution range from 405 m to 5 m. The resolution ratio of each nested domain was 1/3. Total number of grid points were 13 million, and the time step was 0.1 seconds. Tsunami sources of 2011 Tohoku-oki earthquake were tested. The inundation prediction up to 2 hours after the

  3. Super-resolution imaging of low-frequency sound sources using a corrected monopole time reversal method

    Science.gov (United States)

    Bi, Chuan-Xing; Li, Yong-Chang; Zhang, Yong-Bin; Xu, Liang

    2017-12-01

    A limitation of the monopole time reversal (MTR) method, which records and retransmits the monopole field only, is that the spatial resolution of the focus cannot be better than half a wavelength, and therefore it is not suitable for locating low-frequency sound sources. In this paper, the time-reversed pressure field obtained by the MTR method is first transformed into the wavenumber domain, and is then decomposed into a filter term that controls the spatial resolution of the focus and a source term that is related to the sound source and focusing plane. Subsequently, a correction is made to the time-reversed pressure field of the MTR method by replacing its filter with the filter for the time-reversed pressure gradient field of the dipole TR (DTR) method, a constant filter and an empirical filter, which makes it possible to include many more evanescent waves and obtain subwavelength focusing. Numerical simulation and experimental results show that compared to the original MTR method, the corrected one is able to dramatically improve the spatial resolution of the focus at low frequencies. It is also found that the constant filter is applicable when the signal-to-noise ratio (SNR) is high (generally above 30 dB), the filter for the time-reversed pressure gradient field of the DTR method works stably even in the situation of low SNR, and the empirical filter performs best when the SNR is above 10 dB.

  4. The Resolution Integral as a metric of performance for diagnostic grey-scale imaging

    International Nuclear Information System (INIS)

    Pye, S D; Ellis, W

    2011-01-01

    There is a strong clinical need for objective measurements of grey-scale ultrasound imaging performance. We have previously proposed the Resolution Integral R as a suitable metric, because it defines the ratio of the penetration of an ultrasound beam in soft tissue to the ultrasound beam width. Transducers with good performance combine deep penetration with high lateral resolution, giving a large ratio of penetration to beam-width. Depth of Field L R and Characteristic Resolution D R are defined such that R L R /D R . L R defines a region of optimum resolution, and D R is representative of the lateral and elevation resolution within L R . We report the results of a survey of the imaging performance of 79 models of ultrasound scanner made using an Edinburgh Pipe Phantom to measure values of R, L R and D R . The scanners were manufactured between 1986 and 2009 and were from 23 manufacturers. A total of 171 different transducers were tested, including linear and convex arrays, and mechanical sector probes. The results demonstrate that R successfully distinguishes transducers with differing levels of performance, and that L R and D R characterise probes suitable for different clinical applications. The characteristics of individual probes are concisely quantified and displayed on a plot of L R vs D R .

  5. A homemade high-resolution orthogonal-injection time-of-flight mass spectrometer with a heated capillary inlet

    International Nuclear Information System (INIS)

    Guo Changjuan; Huang Zhengxu; Gao Wei; Nian Huiqing; Chen Huayong; Dong Junguo; Shen Guoying; Fu Jiamo; Zhou Zhen

    2008-01-01

    We describe a homemade high-resolution orthogonal-injection time-of-flight (O-TOF) mass spectrometer combing a heated capillary inlet. The O-TOF uses a heated capillary tube combined with a radio-frequency only quadrupole (rf-only quadrupole) as an interface to help the ion transmission from the atmospheric pressure to the low-pressure regions. The principle, configuration of the O-TOF, and the performance of the instrument are introduced in this paper. With electrospray ion source, the performances of the mass resolution, the sensitivity, the mass range, and the mass accuracy are described. We also include our results obtained by coupling atmospheric pressure matrix-assisted laser deporption ionization with this instrument

  6. Performance evaluation of a sub-millimeter spatial resolution PET detector module using a digital silicon photomultiplier coupled LGSO array

    Energy Technology Data Exchange (ETDEWEB)

    Leem, Hyun Tae [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Choi, Yong, E-mail: ychoi@sogang.ac.kr [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Kim, Kyu Bom; Lee, Sangwon [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Yamamoto, Seiichi [Department of Medical Technology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Yeom, Jung-Yeol, E-mail: jungyeol@korea.ac.kr [School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of)

    2017-02-21

    In positron emission tomography (PET) for breast, brain and small animal imaging, the spatial resolution of a PET detector is crucial to obtain high quality PET images. In this study, a PET detector for sub-millimeter spatial resolution imaging purpose was assembled using 4×4 pixels of a digital silicon photomultiplier (dSiPM, DPC-3200-22-44, Philips) coupled with a 15×15 LGSO array with BaSO{sub 4} reflector, and a 1 mm thick acrylic light guide for light distribution between the dSiPM pixels. The active area of each dSiPM pixel was 3.2×3.9 mm{sup 2} and the size of each LGSO scintillator element was 0.7×0.7×6 mm{sup 3}. In this paper, we experimentally demonstrated the performance of the PET detector by measuring the energy resolution, 2D flood map, peak to valley (P/V) ratio, and coincidence resolving time (CRT). All measurements were performed at a temperature of 10±1 ℃. The average energy resolution was 15.6% (without correcting for saturation effects) at 511 keV and the best CRT was 242±5 ps. The 2D flood map obtained with an energy window of 400–600 keV demonstrated clear identification of all pixels, and the average P/V ratio of the X- and Y-directions were 7.31 and 7.81, respectively. This study demonstrated that the PET detector could be suitable for application in high resolution PET while achieving good timing resolution.

  7. Divergence identities in curved space-time. A resolution of the stress-energy problem

    International Nuclear Information System (INIS)

    Yilmaz, H.; Tufts Univ., Medford, MA

    1989-01-01

    It is noted that the joint use of two basic differential identities in curved space-time, namely. 1) the Einstein-Hilbert identity (1915), and 2) the identity of P. Freud (1939), permits a viable alternative to general relativity and a resolution of the field stress-energy' problem of the gravitational theory. (orig.)

  8. An FPGA-Integrated Time-to-Digital Converter Based on a Ring Oscillator for Programmable Delay Line Resolution Measurement

    Directory of Open Access Journals (Sweden)

    Chao Chen

    2014-01-01

    Full Text Available We describe the architecture of a time-to-digital converter (TDC, specially intended to measure the delay resolution of a programmable delay line (PDL. The configuration, which consists of a ring oscillator, a frequency divider (FD, and a period measurement circuit (PMC, is implemented in a field programmable gate array (FPGA device. The ring oscillator realized in loop containing a PDL and a look-up table (LUT generates periodic oscillatory pulses. The FD amplifies the oscillatory period from nanosecond range to microsecond range. The time-to-digital conversion is based on counting the number of clock cycles between two consecutive pulses of the FD by the PMC. Experiments have been conducted to verify the performance of the TDC. The achieved relative errors for four PDLs are within 0.50%–1.21% and the TDC has an equivalent resolution of about 0.4 ps.

  9. Factors Influencing Time Resolution of Scintillators and Ways to Improve Them

    CERN Document Server

    Lecoq, P; Brunner, S; Meyer, T; Auffray, E; Knapitsch, A; Jarron, P

    2010-01-01

    The renewal of interest in Time of Flight Positron Emission Tomography (TOF-PET), as well as the necessity to precisely tag events in high energy physics (HEP) experiments at future colliders are pushing for an optimization of all factors affecting the time resolution of the whole acquisition chain comprising the crystal, the photo detector, and the electronics. The time resolution of a scintillator-based detection system is determined by the rate of photo electrons at the detection threshold, which depends on the time distribution of photons being converted in the photo detector. The possibility to achieve time resolution of about 100 ps Full Width at Half Maximum (FWHM) requires an optimization of the light production in the scintillator, the light transport and its transfer from the scintillator to the photo detector. In order to maximize the light yield, and in particular the density of photons in the first nanosecond, while minimizing the rise time and decay time, particular attention must be paid to the...

  10. Does image quality matter? Impact of resolution and noise on mammographic task performance

    International Nuclear Information System (INIS)

    Saunders, Robert S. Jr.; Baker, Jay A.; Delong, David M.; Johnson, Jeff P.; Samei, Ehsan

    2007-01-01

    The purpose of this study was to examine the effects of different resolution and noise levels on task performance in digital mammography. This study created an image set with images at three different resolution levels, corresponding to three digital display devices, and three different noise levels, with noise magnitudes similar to full clinical dose, half clinical dose, and quarter clinical dose. The images were read by five experienced breast imaging radiologists. The data were then analyzed to compute two accuracy statistics (overall classification accuracy and lesion detection accuracy) and performance at four diagnostic tasks (detection of microcalcifications, benign masses, malignant masses, and discrimination of benign and malignant masses). Human observer results showed decreasing display resolution had little effect on overall classification accuracy and individual diagnostic task performance, but increasing noise caused overall classification accuracy to decrease by a statistically significant 21% as the breast dose went to one quarter of its normal clinical value. The noise effects were most prominent for the tasks of microcalcification detection and mass discrimination. When the noise changed from full clinical dose to quarter clinical dose, the microcalcification detection performance fell from 89% to 67% and the mass discrimination performance decreased from 93% to 79%, while malignant mass detection performance remained relatively constant with values of 88% and 84%, respectively. As a secondary aim, the image set was also analyzed by two observer models to examine whether their performance was similar to humans. Observer models differed from human observers and each other in their sensitivity to resolution degradation and noise. The primary conclusions of this study suggest that quantum noise appears to be the dominant image quality factor in digital mammography, affecting radiologist performance much more profoundly than display resolution

  11. Mobile Robots Path Planning Using the Overall Conflict Resolution and Time Baseline Coordination

    Directory of Open Access Journals (Sweden)

    Yong Ma

    2014-01-01

    Full Text Available This paper aims at resolving the path planning problem in a time-varying environment based on the idea of overall conflict resolution and the algorithm of time baseline coordination. The basic task of the introduced path planning algorithms is to fulfill the automatic generation of the shortest paths from the defined start poses to their end poses with consideration of generous constraints for multiple mobile robots. Building on this, by using the overall conflict resolution, within the polynomial based paths, we take into account all the constraints including smoothness, motion boundary, kinematics constraints, obstacle avoidance, and safety constraints among robots together. And time baseline coordination algorithm is proposed to process the above formulated problem. The foremost strong point is that much time can be saved with our approach. Numerical simulations verify the effectiveness of our approach.

  12. Determination of atomic positions from time resolved high resolution transmission electron microscopy images.

    Science.gov (United States)

    Hussaini, Zahra; Lin, Pin Ann; Natarajan, Bharath; Zhu, Wenhui; Sharma, Renu

    2018-03-01

    For many reaction processes, such as catalysis, phase transformations, nanomaterial synthesis etc., nanoscale observations at high spatial (sub-nanometer) and temporal (millisecond) resolution are required to characterize and comprehend the underlying factors that favor one reaction over another. The combination of such spatial and temporal resolution (up to 600 µs), while rich in information, produces a large number of snapshots, each of which must be analyzed to obtain the structural (and thereby chemical) information. Here we present a methodology for automated quantitative measurement of real-time atomic position fluctuations in a nanoparticle. We leverage a combination of several image processing algorithms to precisely identify the positions of the atomic columns in each image. A geometric model is then used to measure the time-evolution of distances and angles between neighboring atomic columns to identify different phases and quantify local structural fluctuations. We apply this technique to determine the atomic-level fluctuations in the relative fractions of metal and metal-carbide phases in a cobalt catalyst nanoparticle during single-walled carbon nanotube (SWCNT) growth. These measurements provided a means to obtain the number of carbon atoms incorporated into and released from the catalyst particle, thereby helping resolve carbon reaction pathways during SWCNT growth. Further we demonstrate the use of this technique to measure the reaction kinetics of iron oxide reduction. Apart from reducing the data analysis time, the statistical approach allows us to measure atomic distances with sub-pixel resolution. We show that this method can be applied universally to measure atomic positions with a precision of 0.01 nm from any set of atomic-resolution video images. With the advent of high time-resolution direct detection cameras, we anticipate such methods will be essential in addressing the metrology problem of quantifying large datasets of time

  13. Real-time underwater object detection based on an electrically scanned high-resolution sonar

    DEFF Research Database (Denmark)

    Henriksen, Lars

    1994-01-01

    The paper describes an approach to real time detection and tracking of underwater objects, using image sequences from an electrically scanned high-resolution sonar. The use of a high resolution sonar provides a good estimate of the location of the objects, but strains the computers on board, beca...... of different on-board sensors also makes it possible to scan a map of a larger area of the seabed in world coordinates. The work is in collaboration with partners under MAST-C-T90-0059...

  14. A high-resolution time interpolator based on a delay locked loop and an RC delay line

    CERN Document Server

    Mota, M

    1999-01-01

    An architecture for a time interpolation circuit with an rms error of ~25 ps has been developed in a 0.7- mu m CMOS technology. It is based on a delay locked loop (DLL) driven by a 160-MHz reference clock and a passive RC delay line controlled by an autocalibration circuit. Start-up calibration of the RC delay line is performed using code density tests (CDT). The very small temperature/voltage dependence of R and C parameters and the self calibrating DLL results in a low- power, high-resolution time interpolation circuit in a standard digital CMOS technology. (11 refs).

  15. A Compressed Sensing Based Method for Reducing the Sampling Time of A High Resolution Pressure Sensor Array System.

    Science.gov (United States)

    Sun, Chenglu; Li, Wei; Chen, Wei

    2017-08-10

    For extracting the pressure distribution image and respiratory waveform unobtrusively and comfortably, we proposed a smart mat which utilized a flexible pressure sensor array, printed electrodes and novel soft seven-layer structure to monitor those physiological information. However, in order to obtain high-resolution pressure distribution and more accurate respiratory waveform, it needs more time to acquire the pressure signal of all the pressure sensors embedded in the smart mat. In order to reduce the sampling time while keeping the same resolution and accuracy, a novel method based on compressed sensing (CS) theory was proposed. By utilizing the CS based method, 40% of the sampling time can be decreased by means of acquiring nearly one-third of original sampling points. Then several experiments were carried out to validate the performance of the CS based method. While less than one-third of original sampling points were measured, the correlation degree coefficient between reconstructed respiratory waveform and original waveform can achieve 0.9078, and the accuracy of the respiratory rate (RR) extracted from the reconstructed respiratory waveform can reach 95.54%. The experimental results demonstrated that the novel method can fit the high resolution smart mat system and be a viable option for reducing the sampling time of the pressure sensor array.

  16. A Compressed Sensing Based Method for Reducing the Sampling Time of A High Resolution Pressure Sensor Array System

    Directory of Open Access Journals (Sweden)

    Chenglu Sun

    2017-08-01

    Full Text Available For extracting the pressure distribution image and respiratory waveform unobtrusively and comfortably, we proposed a smart mat which utilized a flexible pressure sensor array, printed electrodes and novel soft seven-layer structure to monitor those physiological information. However, in order to obtain high-resolution pressure distribution and more accurate respiratory waveform, it needs more time to acquire the pressure signal of all the pressure sensors embedded in the smart mat. In order to reduce the sampling time while keeping the same resolution and accuracy, a novel method based on compressed sensing (CS theory was proposed. By utilizing the CS based method, 40% of the sampling time can be decreased by means of acquiring nearly one-third of original sampling points. Then several experiments were carried out to validate the performance of the CS based method. While less than one-third of original sampling points were measured, the correlation degree coefficient between reconstructed respiratory waveform and original waveform can achieve 0.9078, and the accuracy of the respiratory rate (RR extracted from the reconstructed respiratory waveform can reach 95.54%. The experimental results demonstrated that the novel method can fit the high resolution smart mat system and be a viable option for reducing the sampling time of the pressure sensor array.

  17. Daily High-Resolution Flood Maps of Africa: 1992-present with Near Real Time Updates

    Science.gov (United States)

    Picton, J.; Galantowicz, J. F.; Root, B.

    2016-12-01

    The ability to characterize past and current flood extents frequently, accurately, and at high resolution is needed for many applications including risk assessment, wetlands monitoring, and emergency management. However, remote sensing methods have not been capable of meeting all of these requirements simultaneously. Cloud cover too often obscures the surface for visual and infrared sensors and observations from radar sensors are too infrequent to create consistent historical databases or monitor evolving events. Lower-resolution (10-50 km) passive microwave sensors, such as SSM/I, AMSR-E, and AMSR2, are sensitive to water cover, acquire useful data during clear and cloudy conditions, have revisit periods of up to twice daily, and provide a continuous record of data from 1992 to the present. What they lack most is the resolution needed to map flood extent. We will present results from a flood mapping system capable of producing high-resolution (90-m) flood extent depictions from lower resolution microwave data. The system uses the strong sensitivity of microwave data to surface water coverage combined with land surface and atmospheric data to derive daily flooded fraction estimates on a sensor-footprint basis. The system downscales flooded fraction to make high-resolution Boolean flood extent depictions that are spatially continuous and consistent with the lower resolution data. The downscaling step is based on a relative floodability (RF) index derived from higher-resolution topographic and hydrological data. We process RF to create a flooded fraction threshold map that relates each 90-m grid point to the surrounding terrain at the microwave scale. We have derived daily, 90-m resolution flood maps for Africa covering 1992-present using SSM/I, AMSR-E, and AMSR2 data and we are now producing new daily maps in near real time. The flood maps are being used by the African Risk Capacity (ARC) Agency to underpin an intergovernmental river flood insurance program in

  18. Performance and results of the high-resolution biogeochemical model PELAGOS025 within NEMO

    Science.gov (United States)

    Epicoco, I.; Mocavero, S.; Macchia, F.; Vichi, M.; Lovato, T.; Masina, S.; Aloisio, G.

    2015-12-01

    The present work aims at evaluating the scalability performance of a high-resolution global ocean biogeochemistry model (PELAGOS025) on massive parallel architectures and the benefits in terms of the time-to-solution reduction. PELAGOS025 is an on-line coupling between the physical ocean model NEMO and the BFM biogeochemical model. Both the models use a parallel domain decomposition along the horizontal dimension. The parallelisation is based on the message passing paradigm. The performance analysis has been done on two parallel architectures, an IBM BlueGene/Q at ALCF (Argonne Leadership Computing Facilities) and an IBM iDataPlex with Sandy Bridge processors at CMCC (Euro Mediterranean Center on Climate Change). The outcome of the analysis demonstrated that the lack of scalability is due to several factors such as the I/O operations, the memory contention, the load unbalancing due to the memory structure of the BFM component and, for the BlueGene/Q, the absence of a hybrid parallelisation approach.

  19. Real-time and quantitative isotropic spatial resolution susceptibility imaging for magnetic nanoparticles

    Science.gov (United States)

    Pi, Shiqiang; Liu, Wenzhong; Jiang, Tao

    2018-03-01

    The magnetic transparency of biological tissue allows the magnetic nanoparticle (MNP) to be a promising functional sensor and contrast agent. The complex susceptibility of MNPs, strongly influenced by particle concentration, excitation magnetic field and their surrounding microenvironment, provides significant implications for biomedical applications. Therefore, magnetic susceptibility imaging of high spatial resolution will give more detailed information during the process of MNP-aided diagnosis and therapy. In this study, we present a novel spatial magnetic susceptibility extraction method for MNPs under a gradient magnetic field, a low-frequency drive magnetic field, and a weak strength high-frequency magnetic field. Based on this novel method, a magnetic particle susceptibility imaging (MPSI) of millimeter-level spatial resolution (<3 mm) was achieved using our homemade imaging system. Corroborated by the experimental results, the MPSI shows real-time (1 s per frame acquisition) and quantitative abilities, and isotropic high resolution.

  20. Numerical Studies on Time Resolution of Micro-Pattern Gaseous Detectors

    Science.gov (United States)

    Bhattacharya, Purba; Majumdar, Nayana; Mukhopadhyay, Supratik; Bhattacharya, Sudeb

    2018-02-01

    The Micro-Pattern Gaseous Detectors offer excellent spatial and temporal resolution in harsh radiation environments of high-luminosity colliders. In this work, an attempt has been made to establish an algorithm for estimating the time resolution of different MPGDs. It has been estimated numerically on the basis of two aspects, statistics and distribution of primary electrons and their diffusion in gas medium, while ignoring their multiplication. The effect of detector design parameters, field configuration and the composition of gas mixture on the resolution have also been investigated. Finally, a modification in the numerical approach considering the threshold limit of detecting the signal has been done and tested for the RPC detector for its future implementation in case of MPGDs.

  1. The Performance of Fine Resolution Neutron Powder Diffractometer at PTBIN-BATAN

    Directory of Open Access Journals (Sweden)

    A. Fajar

    2010-04-01

    Full Text Available We describe the performance of a fine resolution neutron powder diffractometer, DN3, which has been installed at the neutron guide (NG2 in the Neutron Guide Hall about 71 m away from the Multipurpose G. A. Siwabessy reactor core. DN3 has a multi-detector system which consists of 32 3He neutron detectors and soller-type collimation. The resolution curve of the instrument was found to have little variation over a wide angular region. The best resolution is Δ2θ (FWHM of 0.23º and Δd / d of 5x10-3, where 2θ and d are scattering angle and d-spacing, respectively. The instrument provides sample environment of low temperatures using a cryostat having a temperature range of 10-300K. Several experimental results, interlaboratory comparison study and he next activities to improve the performance of DN3 equipment have also been discussed.

  2. High resolution dynamical downscaling of air temperature and relative humidity: performance assessment of WRF for Portugal

    Science.gov (United States)

    Menezes, Isilda; Pereira, Mário; Moreira, Demerval; Carvalheiro, Luís; Bugalho, Lourdes; Corte-Real, João

    2017-04-01

    Air temperature and relative humidity are two of the atmospheric variables with higher impact on human and natural systems, contributing to define the stress/comfortable conditions, affecting the productivity and health of the individuals as well as diminishing the resilience to other environmental hazards. Atmospheric regional models, driven by large scale forecasts from global circulation models, are the best way to reproduce such environmental conditions in high space-time resolution. This study is focused on the performance assessment of the WRF mesoscale model to perform high resolution dynamical downscaling for Portugal with three two-way nested grids, at 60 km, 20 km and 5 km horizontal resolution. The simulations of WRF models were produced with different initial and boundary forcing conditions. The NCEP-FNL Operational Global Analysis data available on 1-degree by 1-degree grid every six hours and ERA-Interim reanalyses dataset were used to drive the models. Two alternative configurations of the WRF model, including planetary boundary, layer schemes, microphysics, land-surface models, radiation schemes, were used and tested within the 5 km spatial resolution domain. Simulations of air temperature and relative humidity were produced for January and July of 2016 and compared with the observed datasets provided by the Instituto Português do Mar e da Atmosfera (IPMA) for 83 weather stations. Different performance measures of bias, precision, and accuracy were used, namely normalized bias, standard deviation, mean absolute error, root mean square error, bias of root mean square error as well as correlation based measures (e.g., coefficient of determination) and goodness of fit measures (index of agreement). Main conclusions from the obtained results reveal: (i) great similarity between the spatial patterns of the simulated and observed fields; (ii) only small differences between simulations produced with ERA-Interim and NCEP-FNL, in spite of some differences

  3. Time resolution of the plastic scintillator strips with matrix photomultiplier readout for J-PET tomograph

    Science.gov (United States)

    Moskal, P.; Rundel, O.; Alfs, D.; Bednarski, T.; Białas, P.; Czerwiński, E.; Gajos, A.; Giergiel, K.; Gorgol, M.; Jasińska, B.; Kamińska, D.; Kapłon, Ł.; Korcyl, G.; Kowalski, P.; Kozik, T.; Krzemień, W.; Kubicz, E.; Niedźwiecki, Sz; Pałka, M.; Raczyński, L.; Rudy, Z.; Sharma, N. G.; Słomski, A.; Silarski, M.; Strzelecki, A.; Wieczorek, A.; Wiślicki, W.; Witkowski, P.; Zieliński, M.; Zoń, N.

    2016-03-01

    Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the determination of time of the interaction of 0.511 MeV gamma quanta in plastic scintillators is much lower. As the major point of the article, a method allowing to record timestamps of several photons, at two ends of the scintillator strip, by means of matrix of silicon photomultipliers (SiPM) is introduced. As a result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with the growing number of photomultipliers, and that the 2× 5 configuration at two ends allowing to read twenty timestamps, constitutes an optimal solution. The conducted simulations accounted for the emission time distribution, photon transport and absorption inside the scintillator, as well as quantum efficiency and transit time spread of photosensors, and were checked based on the experimental results. Application of the 2× 5 matrix of SiPM allows for achieving the coincidence resolving time in positron emission tomography of ≈ 0.170 ns for 15 cm axial field-of-view (AFOV) and ≈ 0.365 ns for 100 cm AFOV. The results open perspectives for construction of a cost-effective TOF-PET scanner with significantly better TOF resolution and larger AFOV with respect to the current TOF-PET modalities.

  4. Time-resolved PIV technique for high temporal resolution measurement of mechanical prosthetic aortic valve fluid dynamics.

    Science.gov (United States)

    Kaminsky, R; Morbiducci, U; Rossi, M; Scalise, L; Verdonck, P; Grigioni, M

    2007-02-01

    Prosthetic heart valves (PHVs) have been used to replace diseased native valves for more than five decades. Among these, mechanical PHVs are the most frequently implanted. Unfortunately, these devices still do not achieve ideal behavior and lead to many complications, many of which are related to fluid mechanics. The fluid dynamics of mechanical PHVs are particularly complex and the fine-scale characteristics of such flows call for very accurate experimental techniques. Adequate temporal resolution can be reached by applying time-resolved PIV, a high-resolution dynamic technique which is able to capture detailed chronological changes in the velocity field. The aim of this experimental study is to investigate the evolution of the flow field in a detailed time domain of a commercial bileaflet PHV in a mock-loop mimicking unsteady conditions, by means of time-resolved 2D Particle Image Velocimetry (PIV). The investigated flow field corresponded to the region immediately downstream of the valve plane. Spatial resolution as in "standard" PIV analysis of prosthetic valve fluid dynamics was used. The combination of a Nd:YLF high-repetition-rate double-cavity laser with a high frame rate CMOS camera allowed a detailed, highly temporally resolved acquisition (up to 10000 fps depending on the resolution) of the flow downstream of the PHV. Features that were observed include the non-homogeneity and unsteadiness of the phenomenon and the presence of large-scale vortices within the field, especially in the wake of the valve leaflets. Furthermore, we observed that highly temporally cycle-resolved analysis allowed the different behaviors exhibited by the bileaflet valve at closure to be captured in different acquired cardiac cycles. By accurately capturing hemodynamically relevant time scales of motion, time-resolved PIV characterization can realistically be expected to help designers in improving PHV performance and in furnishing comprehensive validation with experimental data

  5. Pulse Rise Time Characterization of a High Pressure Xenon Gamma Detector for use in Resolution Enhancement

    CERN Document Server

    Troyer, G L

    2000-01-01

    High pressure xenon ionization chamber detectors are possible alternatives to traditional thallium doped sodium iodide (NaI(Tl)) and hyperpure germanium as gamma spectrometers in certain applications. Xenon detectors incorporating a Frisch grid exhibit energy resolutions comparable to cadmium/zinc/telluride (CZT) (e.g. 2% (at) 662keV) but with far greater sensitive volumes. The Frisch grid reduces the position dependence of the anode pulse risetimes, but it also increases the detector vibration sensitivity, anode capacitance, voltage requirements and mechanical complexity. We have been investigating the possibility of eliminating the grid electrode in high-pressure xenon detectors and preserving the high energy resolution using electronic risetime compensation methods. A two-electrode cylindrical high pressure xenon gamma detector coupled to time-to-amplitude conversion electronics was used to characterize the pulse rise time of deposited gamma photons. Time discrimination was used to characterize the pulse r...

  6. Signal Tracking Beyond the Time Resolution of an Atomic Sensor by Kalman Filtering

    Science.gov (United States)

    Jiménez-Martínez, Ricardo; Kołodyński, Jan; Troullinou, Charikleia; Lucivero, Vito Giovanni; Kong, Jia; Mitchell, Morgan W.

    2018-01-01

    We study causal waveform estimation (tracking) of time-varying signals in a paradigmatic atomic sensor, an alkali vapor monitored by Faraday rotation probing. We use Kalman filtering, which optimally tracks known linear Gaussian stochastic processes, to estimate stochastic input signals that we generate by optical pumping. Comparing the known input to the estimates, we confirm the accuracy of the atomic statistical model and the reliability of the Kalman filter, allowing recovery of waveform details far briefer than the sensor's intrinsic time resolution. With proper filter choice, we obtain similar benefits when tracking partially known and non-Gaussian signal processes, as are found in most practical sensing applications. The method evades the trade-off between sensitivity and time resolution in coherent sensing.

  7. Accuracy VS Performance: Finding the Sweet Spot in the Geospatial Resolution of Satellite Metadata

    Science.gov (United States)

    Baskin, W. E.; Mangosing, D. C.; Rinsland, P. L.

    2010-12-01

    NASA’s Atmospheric Science Data Center (ASDC) and the Cloud-Aerosol LIDAR and Infrared Pathfinder Satellite Observation (CALIPSO) team at the NASA Langley Research Center recently collaborated in the development of a new CALIPSO Search and Subset web application. The web application is comprised of three elements: (1) A PostGIS-enabled PostgreSQL database system, which is used to store temporal and geospatial metadata from CALIPSO’s LIDAR, Infrared, and Wide Field Camera datasets, (2) the SciFlo engine, which is a data flow engine that enables semantic, scientific data flow executions in a grid or clustered network computational environment, and (3) PHP-based web application that incorporates some Web 2.0 / AJAX technologies used in the web interface. The search portion of the web application leverages geodetic indexing and search capabilities that became available in the February 2010 release of PostGIS version1.5. This presentation highlights the lessons learned in experimenting with various geospatial resolutions of CALIPSO’s LIDAR sensor ground track metadata. Details of the various spatial resolutions, spatial database schema designs, spatial indexing strategies, and performance results will be discussed. The focus will be on illustrating our findings on the spatial resolutions for ground track metadata that optimized search time and search accuracy in the CALIPSO Search and Subset Application. The CALIPSO satellite provides new insight into the role that clouds and atmospheric aerosols (airborne particles) play in regulating Earth's weather, climate, and air quality. CALIPSO combines an active LIDAR instrument with passive infrared and visible imagers to probe the vertical structure and properties of thin clouds and aerosols over the globe. The CALIPSO satellite was launched on April 28, 2006 and is part of the A-train satellite constellation. The ASDC in Langley’s Science Directorate leads NASA’s program for the processing, archival and

  8. Effectiveness and resolution of tests for evaluating the performance of cutting fluids in machining aerospace alloys

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo; Axinte, Dragos A.

    2008-01-01

    The paper discusses effectiveness and resolution of five cutting tests (turning, milling, drilling, tapping, VIPER grinding) and their quality output measures used in a multi-task procedure for evaluating the performance of cutting fluids when machining aerospace materials. The evaluation takes...

  9. Investigating the Effects of Group Practice Performed Using Psychodrama Techniques on Adolescents' Conflict Resolution Skills

    Science.gov (United States)

    Karatas, Zeynep

    2011-01-01

    The aim of this study is to examine the effects of group practice which is performed using psychodrama techniques on adolescents' conflict resolution skills. The subjects, for this study, were selected among the high school students who have high aggression levels and low problem solving levels attending Haci Zekiye Arslan High School, in Nigde.…

  10. Performance analysis of different PSF shapes for the quad-HIDAC PET submillimetre resolution recovery

    Energy Technology Data Exchange (ETDEWEB)

    Ortega Maynez, Leticia, E-mail: lortega@uacj.mx [Departamento de Ingenieria Eectrica y Computacion , Universidad Autonoma de Ciudad Juarez, Avenida del Charro 450 Norte, C.P. 32310 Ciudad Juarez, Chihuahua (Mexico); Dominguez de Jesus Ochoa, Humberto; Villegas Osiris Vergara, Osslan; Gordillo, Nelly; Guadalupe Cruz Sanchez, Vianey; Gutierrez Casas, Efren David [Departamento de Ingenieria Eectrica y Computacion, Universidad Autonoma de Ciudad Juarez, Avenida del Charro 450 Norte, C.P. 32310 Ciudad Juarez, Chihuahua (Mexico)

    2011-10-01

    In pre-clinical applications, it is quite important to preserve the image resolution because it is necessary to show the details of structures of small animals. Therefore, small animal PET scanners require high spatial resolution and good sensitivity. For the quad-HIDAC PET scanner, which has virtually continuous spatial sampling; improvements in resolution, noise and contrast are obtained as a result of avoiding artifacts introduced by binning the data into sampled projections used during the reconstruction process. In order to reconstruct high-resolution images in 3D-PET, background correction and resolution recovery are included within the Maximum Likelihood list-mode Expectation Maximization reconstruction model. This paper, introduces the performance analysis of the Gaussian, Laplacian and Triangular kernels. The Full-Width Half-Maximum used for each kernel was varied from 0.8 to 1.6 mm. For each quality compartment within the phantom, transaxial middle slices from the 3D reconstructed images are shown. Results show that, according to the quantitative measures, the triangular kernel has the best performance.

  11. Activity on improving performance of time-of-flight detector at CDF

    International Nuclear Information System (INIS)

    Menzione, A.; Cerri, C.; Vataga, E.; Prokoshin, F.; Tokar, S.

    2002-01-01

    The paper describes activity on improving the time resolution of the Time-of-Flight detector at CDF. The main goal of the detector is the identification of kaons and pions for b-quark (B-meson) flavour tagging. Construction of the detector has been described as well as proposals on detector design changes to improve its time resolution. Monte Carlo simulation of the detector response to MIP was performed. The results of the simulation showed that the proposed modifications (at least with currently available materials) bring modest or no improvement of the detector time resolution. An automated set-up was assembled to test and check out the changes in the electronic readout system of the detector. Sophisticated software has been developed for this set-up to provide control of the system as well as processing and presentation of data from the detector. This software can perform various tests using different implementations of the hardware set-up

  12. Time resolution requirements for civilian radioxenon emission data for the CTBT verification regime.

    Science.gov (United States)

    De Meutter, Pieter; Camps, Johan; Delcloo, Andy; Deconninck, Benoît; Termonia, Piet

    2018-02-01

    The capability of the noble gas component of the International Monitoring System as a verification tool for the Comprehensive Nuclear-Test-Ban Treaty is deteriorated by a background of radioxenon emitted by civilian sources. One of the possible approaches to deal with this issue, is to simulate the daily radioxenon concentrations from these civilian sources at noble gas stations by using atmospheric transport models. In order to accurately quantify the contribution from these civilian sources, knowledge on the releases is required. However, such data are often not available and furthermore it is not clear what temporal resolution such data should have. In this paper, we assess which temporal resolution is required to best model the 133 Xe contribution from civilian sources at noble gas stations in an operational context. We consider different sampling times of the noble gas stations and discriminate between nearby and distant sources. We find that for atmospheric transport and dispersion problems on a scale of 1000 km or more, emission data with subdaily temporal resolution is generally not necessary. However, when the source-receptor distance decreases, time-resolved emission data become more important. The required temporal resolution of emission data thus depends on the transport scale of the problem. In the context of the Comprehensive Nuclear-Test-Ban Treaty, where forty noble gas stations will monitor the whole globe, daily emission data are generally sufficient, but for certain meteorological conditions, better temporally resolved emission data are required. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Hi-Res scan mode in clinical MDCT systems: Experimental assessment of spatial resolution performance.

    Science.gov (United States)

    Cruz-Bastida, Juan P; Gomez-Cardona, Daniel; Li, Ke; Sun, Heyi; Hsieh, Jiang; Szczykutowicz, Timothy P; Chen, Guang-Hong

    2016-05-01

    The introduction of a High-Resolution (Hi-Res) scan mode and another associated option that combines Hi-Res mode with the so-called High Definition (HD) reconstruction kernels (referred to as a Hi-Res/HD mode in this paper) in some multi-detector CT (MDCT) systems offers new opportunities to increase spatial resolution for some clinical applications that demand high spatial resolution. The purpose of this work was to quantify the in-plane spatial resolution along both the radial direction and tangential direction for the Hi-Res and Hi-Res/HD scan modes at different off-center positions. A technique was introduced and validated to address the signal saturation problem encountered in the attempt to quantify spatial resolution for the Hi-Res and Hi-Res/HD scan modes. Using the proposed method, the modulation transfer functions (MTFs) of a 64-slice MDCT system (Discovery CT750 HD, GE Healthcare) equipped with both Hi-Res and Hi-Res/HD modes were measured using a metal bead at nine different off-centered positions (0-16 cm with a step size of 2 cm); at each position, both conventional scans and Hi-Res scans were performed. For each type of scan and position, 80 repeated acquisitions were performed to reduce noise induced uncertainties in the MTF measurements. A total of 15 reconstruction kernels, including eight conventional kernels and seven HD kernels, were used to reconstruct CT images of the bead. An ex vivo animal study consisting of a bone fracture model was performed to corroborate the MTF results, as the detection of this high-contrast and high frequency task is predominantly determined by spatial resolution. Images of this animal model generated by different scan modes and reconstruction kernels were qualitatively compared with the MTF results. At the centered position, the use of Hi-Res mode resulted in a slight improvement in the MTF; each HD kernel generated higher spatial resolution than its counterpart conventional kernel. However, the MTF along the

  14. Parallel Reaction Monitoring: A Targeted Experiment Performed Using High Resolution and High Mass Accuracy Mass Spectrometry.

    Science.gov (United States)

    Rauniyar, Navin

    2015-12-02

    The parallel reaction monitoring (PRM) assay has emerged as an alternative method of targeted quantification. The PRM assay is performed in a high resolution and high mass accuracy mode on a mass spectrometer. This review presents the features that make PRM a highly specific and selective method for targeted quantification using quadrupole-Orbitrap hybrid instruments. In addition, this review discusses the label-based and label-free methods of quantification that can be performed with the targeted approach.

  15. Parallel Reaction Monitoring: A Targeted Experiment Performed Using High Resolution and High Mass Accuracy Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Navin Rauniyar

    2015-12-01

    Full Text Available The parallel reaction monitoring (PRM assay has emerged as an alternative method of targeted quantification. The PRM assay is performed in a high resolution and high mass accuracy mode on a mass spectrometer. This review presents the features that make PRM a highly specific and selective method for targeted quantification using quadrupole-Orbitrap hybrid instruments. In addition, this review discusses the label-based and label-free methods of quantification that can be performed with the targeted approach.

  16. Time Resolution Dependence of Information Measures for Spiking Neurons: Scaling and Universality

    Directory of Open Access Journals (Sweden)

    James P Crutchfield

    2015-08-01

    Full Text Available The mutual information between stimulus and spike-train response is commonly used to monitor neural coding efficiency, but neuronal computation broadly conceived requires more refined and targeted information measures of input-output joint processes. A first step towards that larger goal is todevelop information measures for individual output processes, including information generation (entropy rate, stored information (statisticalcomplexity, predictable information (excess entropy, and active information accumulation (bound information rate. We calculate these for spike trains generated by a variety of noise-driven integrate-and-fire neurons as a function of time resolution and for alternating renewal processes. We show that their time-resolution dependence reveals coarse-grained structural properties of interspike interval statistics; e.g., $tau$-entropy rates that diverge less quickly than the firing rate indicate interspike interval correlations. We also find evidence that the excess entropy and regularized statistical complexity of different types of integrate-and-fire neurons are universal in the continuous-time limit in the sense that they do not depend on mechanism details. This suggests a surprising simplicity in the spike trains generated by these model neurons. Interestingly, neurons with gamma-distributed ISIs and neurons whose spike trains are alternating renewal processes do not fall into the same universality class. These results lead to two conclusions. First, the dependence of information measures on time resolution reveals mechanistic details about spike train generation. Second, information measures can be used as model selection tools for analyzing spike train processes.

  17. High-resolution morphologic and ultrashort time-to-echo quantitative magnetic resonance imaging of the temporomandibular joint

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Won C.; Chang, Eric Y.; Biswas, Reni; Statum, Sheronda; Chung, Christine B. [Veterans Administration San Diego Healthcare System, Department of Radiology, San Diego, CA (United States); University of California, San Diego, School of Medicine, Department of Radiology, San Diego, CA (United States); Tafur, Monica; Du, Jiang; Healey, Robert [University of California, San Diego, School of Medicine, Department of Radiology, San Diego, CA (United States); Kwack, Kyu-Sung [Ajou University Medical Center, Department of Radiology, Wonchon-dong, Yeongtong-gu, Gyeonggi-do, Suwon (Korea, Republic of)

    2016-03-15

    To implement high-resolution morphologic and quantitative magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) using ultrashort time-to-echo (UTE) techniques in cadavers and volunteers. This study was approved by the institutional review board. TMJs of cadavers and volunteers were imaged on a 3-T MR system. High-resolution morphologic and quantitative sequences using conventional and UTE techniques were performed in cadaveric TMJs. Morphologic and UTE quantitative sequences were performed in asymptomatic and symptomatic volunteers. Morphologic evaluation demonstrated the TMJ structures in open- and closed-mouth position. UTE techniques facilitated the visualization of the disc and fibrocartilage. Quantitative UTE MRI was successfully performed ex vivo and in vivo, reflecting the degree of degeneration. There was a difference in the mean UTE T2* values between asymptomatic and symptomatic volunteers. MRI evaluation of the TMJ using UTE techniques allows characterization of the internal structure and quantification of the MR properties of the disc. Quantitative UTE MRI can be performed in vivo with short scan times. (orig.)

  18. Narrowing the Expertise Gap for Predicting Intracranial Aneurysm Hemodynamics: Impact of Solver Numerics versus Mesh and Time-Step Resolution.

    Science.gov (United States)

    Khan, M O; Valen-Sendstad, K; Steinman, D A

    2015-07-01

    Recent high-resolution computational fluid dynamics studies have uncovered the presence of laminar flow instabilities and possible transitional or turbulent flow in some intracranial aneurysms. The purpose of this study was to elucidate requirements for computational fluid dynamics to detect these complex flows, and, in particular, to discriminate the impact of solver numerics versus mesh and time-step resolution. We focused on 3 MCA aneurysms, exemplifying highly unstable, mildly unstable, or stable flow phenotypes, respectively. For each, the number of mesh elements was varied by 320× and the number of time-steps by 25×. Computational fluid dynamics simulations were performed by using an optimized second-order, minimally dissipative solver, and a more typical first-order, stabilized solver. With the optimized solver and settings, qualitative differences in flow and wall shear stress patterns were negligible for models down to ∼800,000 tetrahedra and ∼5000 time-steps per cardiac cycle and could be solved within clinically acceptable timeframes. At the same model resolutions, however, the stabilized solver had poorer accuracy and completely suppressed flow instabilities for the 2 unstable flow cases. These findings were verified by using the popular commercial computational fluid dynamics solver, Fluent. Solver numerics must be considered at least as important as mesh and time-step resolution in determining the quality of aneurysm computational fluid dynamics simulations. Proper computational fluid dynamics verification studies, and not just superficial grid refinements, are therefore required to avoid overlooking potentially clinically and biologically relevant flow features. © 2015 by American Journal of Neuroradiology.

  19. Particle filter-based estimation of inter-frequency phase bias for real-time GLONASS integer ambiguity resolution

    Science.gov (United States)

    Tian, Yumiao; Ge, Maorong; Neitzel, Frank

    2015-11-01

    GLONASS could hardly reach the positioning performance of GPS, especially for fast and real-time precise positioning. One of the reasons is the phase inter-frequency bias (IFB) at the receiver end prevents its integer ambiguity resolution. A number of studies were carried out to achieve the integer ambiguity resolution for GLONASS. Based on some of the revealed IFB characteristics, for instance IFB is a linear function of the received carrier frequency and L1 and L2 have the same IFB in unit of length, most of recent methods recommend estimating the IFB rate together with ambiguities. However, since the two sets of parameters are highly correlated, as demonstrated in previous studies, observations over several hours up to 1 day are needed even with simultaneous GPS observations to obtain a reasonable solution. Obviously, these approaches cannot be applied for real-time positioning. Actually, it can be demonstrated that GLONASS ambiguity resolution should also be available even for a single epoch if the IFB rate is precisely known. In addition, the closer the IFB rate value is to its true value, the larger the fixing RATIO will be. Based on this fact, in this paper, a new approach is developed to estimate the IFB rate by means of particle filtering with the likelihood function derived from RATIO. This approach is evaluated with several sets of experimental data. For both static and kinematic cases, the results show that IFB rates could be estimated precisely just with GLONASS data of a few epochs depending on the baseline length. The time cost with a normal PC can be controlled around 1 s and can be further reduced. With the estimated IFB rate, integer ambiguity resolution is available immediately and as a consequence, the positioning accuracy is improved significantly to the level of GPS fixed solution. Thus the new approach enables real-time precise applications of GLONASS.

  20. Applications of a streak-camera-based imager with simultaneous high space and time resolution

    Science.gov (United States)

    Klick, David I.; Knight, Frederick K.

    1993-01-01

    A high-speed imaging device has been built that is capable of recording several hundred images over a time span of 25 to 400 ns. The imager is based on a streak camera, which provides both spatial and temporal resolution. The system's current angular resolution is 16 X 16 pixels, with a time resolution of 250 ps. It was initially employed to provide 3-D images of objects, in conjunction with a short-pulse (approximately 100 ps) laser. For the 3-D (angle-angle-range) laser radar, the 250 ps time resolution corresponds to a range resolution of 4 cm. In the 3-D system, light from a short-pulse laser (a frequency-doubled, Q-switched, mode-locked Nd:YAG laser operating at a wavelength of 532 nm) flood-illuminates a target of linear dimension approximately 1 m. The returning light from the target is imaged, and the image is dissected by a 16 X 16 array of optical fibers. At the other end of the fiber optic image converter, the 256 fibers form a vertical line array, which is input to the slit of a streak camera. The streak camera sweeps the input line across the output phosphor screen so that horizontal position is directly proportional to time. The resulting 2-D image (fiber location vs. time) at the phosphor is read by an intensified (SIT) vidicon TV tube, and the image is digitized and stored. A computer subsequently decodes the image, unscrambling the linear pixels into an angle-angle image at each time or range bin. We are left with a series of snapshots, each one depicting the portion of target surface in a given range bin. The pictures can be combined to form a 3-D realization of the target. Continuous recording of many images over a short time span is of use in imaging other transient phenomena. These applications share a need for multiple images from a nonrepeatable transient event of time duration on the order of nanoseconds. Applications discussed for the imager include (1) pulsed laser beam diagnostics -- measuring laser beam spatial and temporal structure, (2

  1. Machine vision-based high-resolution weed mapping and patch-sprayer performance simulation

    NARCIS (Netherlands)

    Tang, L.; Tian, L.F.; Steward, B.L.

    1999-01-01

    An experimental machine vision-based patch-sprayer was developed. This sprayer was primarily designed to do real-time weed density estimation and variable herbicide application rate control. However, the sprayer also had the capability to do high-resolution weed mapping if proper mapping techniques

  2. Effects of detector–source distance and detector bias voltage variations on time resolution of general purpose plastic scintillation detectors

    International Nuclear Information System (INIS)

    Ermis, E.E.; Celiktas, C.

    2012-01-01

    Effects of source-detector distance and the detector bias voltage variations on time resolution of a general purpose plastic scintillation detector such as BC400 were investigated. 133 Ba and 207 Bi calibration sources with and without collimator were used in the present work. Optimum source-detector distance and bias voltage values were determined for the best time resolution by using leading edge timing method. Effect of the collimator usage on time resolution was also investigated. - Highlights: ► Effect of the source-detector distance on time spectra was investigated. ► Effect of the detector bias voltage variations on time spectra was examined. ► Optimum detector–source distance was determined for the best time resolution. ► Optimum detector bias voltage was determined for the best time resolution. ► 133 Ba and 207 Bi radioisotopes were used.

  3. The TDCpix Readout ASIC: A 75 ps Resolution Timing Front-End for the Gigatrackerof theNA62 Experiment

    Science.gov (United States)

    Rinella, G. Aglieri; Fiorini, M.; Jarron, P.; Kaplon, J.; Kluge, A.; Martin, E.; Morel, M.; Noy, M.; Perktold, L.; Poltorak, K.

    NA62 is an experiment under development at the CERN Super Proton Synchrotron, aiming at measuring ultra rare kaon decays. The Gigatracker (GTK) detector shall combine on-beam tracking of individual particles with a time resolution of 150 ps rms. The peak flow of particles crossing the detector modules reaches 1.27 MHz/mm2 fora total rateof about 0.75 GHz.Ahybrid siliconpixel detectoris beingdevelopedto meet these requirements. The pixel chip for the Gigatracker (TDCpix) is under design. The TDCpix chip will feature 1800 square pixels of 300×300 μm2 arranged in a matrix of 45 rows × 40 columns. Bump-bonded to a silicon pixel sensor it shall perform time stamping of particle hits with a timing accuracybetter than 200 ps rms and a detection efficiencyabove 99%. The chosen architecture provides full separation of the sensitive analog amplifiers of the pixel matrix from the noisy digital circuits of the TDCs and of the readout blocks. Discriminated hit signals from each pixel are transmitted to the end of column region. An array ofTime to Digital Converters (TDC) is implemented at the bottom of the pixel array. The TDCs are based on time tagging the events with the fine time codes generated by Delay Locked Loops (DLL) and have a nominal time bin of ˜100 ps. Time stamps and time-over-threshold are recorded for each discriminated hit and the correction of the discriminator's time-walk is performed off-detector. Data are continuously transmitted on four 2.4 Gb/s serial output links. Adescription of the on-going design of the final TDCpix is given in this paper. Design choices and some technical implementation details are presented. Aprototype ASIC including thekeycomponents of this architecture has been manufactured. The achievement of specification figures such as a time resolution of the processing chain of 75 ps rms as well as charged particle time stampingwitha resolutionbetterthan200psrmswere demonstratedexperimentally.Asummaryoftheseresultsisalso presented in

  4. Real-time observation of Zn electro-deposition with high-resolution microradiology

    CERN Document Server

    Tsai, W L; Hwu, Y; Chen, C H; Chang, L W; Je, J H; Margaritondo, G

    2003-01-01

    We used phase contrast radiography to study the electro-deposition of Zn in real time and with high lateral resolution. Using unmonochromatic synchrotron X-rays and an optics-less imaging setup, we were able to obtain real-time radiographs of the electro-deposition in situ with mu m resolution. A detailed analysis of the microstructure evolution relates the different growth parameters - such as the electric current density, the voltage bias, the pH value and the ion concentration - to very different growth morphology, ranging from film, porous, whisker and dendrite deposition. This link is both global and local. Local variations of the metal ion concentration in the electrolyte were also successfully imaged and the density profile is used to compare with the standard theory to explain the phenomenon of metal ion depletion near the electrode. The potential application of this technique to study growth with micropatterned electrodes and pulsed electric current is evaluated.

  5. SMBOs: buying time or improving performance?

    OpenAIRE

    Zhou, D; Jelic, R; Wright, M

    2014-01-01

    On the basis of an empirical analysis of 491 UK recent secondary management buyouts (SMBOs), we find strong evidence of a deterioration in long-run abnormal returns following SMBO deals. SMBOs also perform worse than primary buyouts in terms of profitability, labor productivity, and growth. We find no evidence for superior performance of private equity (PE) backed SMBOs, compared with their non-PE-backed counterparts. It appears that a PE firm's reputation and change in management are importa...

  6. Low-Power Amplifier-Discriminators for High Time Resolution Detection

    CERN Document Server

    Despeisse, M; Anghinolfi, F; Tiuraniemi, S; Osmic, F; Riedler, P; Kluge, A; Ceccucci, A

    2009-01-01

    Low-power amplifier-discriminators based on a so-called NINO architecture have been developed with high time resolution for the readout of radiation detectors. Two different circuits were integrated in the NINO13 chip, processed in IBM 130 nm CMOS technology. The LCO version (Low Capacitance and consumption Optimization) was designed for potential use as front-end electronics in the Gigatracker of the NA62 experiment at CERN. It was developed as pixel readout for solid-state pixel detectors to permit minimum ionizing particle detection with less than 180 ps rms resolution per pixel on the output pulse, for power consumption below 300 mu W per pixel. The HCO version (High Capacitance Optimization) was designed with 4 mW power consumption per channel to provide timing resolution below 20 ps rms on the output pulse, for charges above 10 fC. Results presented show the potential of the LCO and HCO circuits for the precise timing readout of solid-state detectors, vacuum tubes or gas detectors, for applications in h...

  7. Implementation and performance of an optical motion tracking system for high resolution brain PET imaging

    Science.gov (United States)

    Lopresti, B. J.; Russo, A.; Jones, W. F.; Fisher, T.; Crouch, D. G.; Altenburger, D. E.; Townsend, D. W.

    1999-12-01

    Head motion during PET scanning is widely regarded as a source of image degradation and resolution loss. Recent improvements in the spatial resolution of state-of-the-art tomographs may be compromised by patient motion during scanning, as these high resolution data will be increasingly susceptible to smaller movements of the head. The authors have developed an opto-electronic motion tracking system based on commercially-available technology that is capable of very accurate real-time measurements of the position and orientation of the patient's head. These positions are transformed to the reference frame of the PET scanner, and could potentially be used to provide motion correction of list-mode emission data on an event-by-event basis.

  8. Performance of high-resolution X-band radar for rainfall measurement in The Netherlands

    Directory of Open Access Journals (Sweden)

    C. Z. van de Beek

    2010-02-01

    Full Text Available This study presents an analysis of 195 rainfall events gathered with the X-band weather radar SOLIDAR and a tipping bucket rain gauge network near Delft, The Netherlands, between May 1993 and April 1994. The aim of this paper is to present a thorough analysis of a climatological dataset using a high spatial (120 m and temporal (16 s resolution X-band radar. This makes it a study of the potential for high-resolution rainfall measurements with non-polarimetric X-band radar over flat terrain. An appropriate radar reflectivity – rain rate relation is derived from measurements of raindrop size distributions and compared with radar – rain gauge data. The radar calibration is assessed using a long-term comparison of rain gauge measurements with corresponding radar reflectivities as well as by analyzing the evolution of the stability of ground clutter areas over time. Three different methods for ground clutter correction as well as the effectiveness of forward and backward attenuation correction algorithms have been studied. Five individual rainfall events are discussed in detail to illustrate the strengths and weaknesses of high-resolution X-band radar and the effectiveness of the presented correction methods. X-band radar is found to be able to measure the space-time variation of rainfall at high resolution, far greater than what can be achieved by rain gauge networks or a typical operational C-band weather radar. On the other hand, SOLIDAR can suffer from receiver saturation, wet radome attenuation as well as signal loss along the path. During very strong convective situations the signal can even be lost completely. In combination with several rain gauges for quality control, high resolution X-band radar is considered to be suitable for rainfall monitoring over relatively small (urban catchments. These results offer great prospects for the new high resolution polarimetric doppler X-band radar IDRA.

  9. Time-domain multiplexed high resolution fiber optics strain sensor system based on temporal response of fiber Fabry-Perot interferometers.

    Science.gov (United States)

    Chen, Jiageng; Liu, Qingwen; He, Zuyuan

    2017-09-04

    We developed a multiplexed strain sensor system with high resolution using fiber Fabry-Perot interferometers (FFPI) as sensing elements. The temporal responses of the FFPIs excited by rectangular laser pulses are used to obtain the strain applied on each FFPI. The FFPIs are connected by cascaded couplers and delay fiber rolls for the time-domain multiplexing. A compact optoelectronic system performing closed-loop cyclic interrogation is employed to improve the sensing resolution and the frequency response. In the demonstration experiment, 3-channel strain sensing with resolutions better than 0.1 nε and frequency response higher than 100 Hz is realized.

  10. Performance characteristics of high-resolution charge-coupled device film digitizers

    Science.gov (United States)

    Lo, Shih-Chung B.; Butson, Philip D.; Lin, Jyh-Shyan; Li, Huai; Freedman, Matthew T.; Mun, Seong K.

    1995-05-01

    This paper describes the performance characteristics of two high resolution charged-coupled device (CCD) film scanners for radiological imaging. The two models of recently developed CCD film scanners made by DBA Systems have been available on the market for ultra high resolution film digitization. One model of the scanner digitizes the film at 21 micrometers and the other one at 42 micrometers . Both systems can be interfaced to a PC. Line-pair, star-pattern and single edge on films were used to test the spatial resolution in the directions perpendicular and parallel to the CCD scan line. Step wedges generated on films through a mammographic system and print transparencies were employed to test the gray value versus the optical density response and variations on a `uniform area.' Geometric distortion of the digitized images was determined to be negligible at less than 1%. This gray value versus optical density response was linearly plotted from optical density (OD) 0 to 2.8. Depending upon optical density regions, gray value fluctuations varied. Both ultra high resolution CCD scanners showed reasonable performance. However, some digital noises were shown in the high OD range.

  11. The TDCpix readout ASIC: A 75ps resolution timing front-end for the NA62 Gigatracker hybrid pixel detector

    CERN Document Server

    Kluge, A; Bonacini, S; Jarron, P; Kaplon, J; Morel, M; Noy, M; Perktold, L; Poltorak, K

    2013-01-01

    The TDCpix is a novel pixel readout ASIC for the NA62 Gigatracker detector. NA62 is a new experiment being installed at the CERN Super Proton Synchrotron. Its Gigatracker detector shall provide on-beam tracking and time stamping of individual particles with a time resolution of 150 ps rms. It will consist of three tracking stations, each with one hybrid pixel sensor. The peak fl ow of particles crossing the detector modules reaches 1.27 MHz/mm 2 for a total rate of about 0.75 GHz. Ten TDCpix chips will be bump-bonded to every silicon pixel sensor. Each chip shall perform time stamping of 100 M particle hits per second with a detection ef fi ciency above 99% and a timing accuracy better than 200 ps rms for an overall three-station-setup time resolution of better than 150 ps. The TDCpix chip has been designed in a 130 nm CMOS technology. It will feature 45 40 square pixels of 300 300 μ m 2 and a complex End of Column peripheral region including an array of TDCs based on DLLs, four high speed serializers, a low...

  12. Now's the Time: Implementing Performance Management

    Science.gov (United States)

    Legutko, Lee V.

    2012-01-01

    During the past several years, school systems have implemented a variety of organizational improvement initiatives, such as Six Sigma, Balanced Scorecards, Baldrige Criteria, activity-based costing, and managing for results. Unfortunately, evidence of sustained success is fleeting as school districts remain trapped in a time warp of command,…

  13. Resolution performance of a 0.60-NA, 364-nm laser direct writer

    Science.gov (United States)

    Allen, Paul C.; Buck, Peter D.

    1990-06-01

    ATEQ has developed a high resolution laser scanning printing engine based on the 8 beam architecture of the CORE- 2000. This printing engine has been incorporated into two systems: the CORE-2500 for the production of advanced masks and reticles and a prototype system for direct write on wafers. The laser direct writer incorporates a through-the-lens alignment system and a rotary chuck for theta alignment. Its resolution performance is delivered by a 0. 60 NA laser scan lens and a novel air-jet focus system. The short focal length high resolution lens also reduces beam position errors thereby improving overall pattern accuracy. In order to take advantage of the high NA optics a high performance focus servo was developed capable of dynamic focus with a maximum error of 0. 15 tm. The focus system uses a hot wire anemometer to measure air flow through an orifice abutting the wafer providing a direct measurement to the top surface of resist independent of substrate properties. Lens specifications are presented and compared with the previous design. Bench data of spot size vs. entrance pupil filling show spot size performance down to 0. 35 m FWHM. The lens has a linearity specification of 0. 05 m system measurements of lens linearity indicate system performance substantially below this. The aerial image of the scanned beams is measured using resist as a threshold detector. An effective spot size is

  14. Development of a real-time transport performance optimization methodology

    Science.gov (United States)

    Gilyard, Glenn

    1996-01-01

    The practical application of real-time performance optimization is addressed (using a wide-body transport simulation) based on real-time measurements and calculation of incremental drag from forced response maneuvers. Various controller combinations can be envisioned although this study used symmetric outboard aileron and stabilizer. The approach is based on navigation instrumentation and other measurements found on state-of-the-art transports. This information is used to calculate winds and angle of attack. Thrust is estimated from a representative engine model as a function of measured variables. The lift and drag equations are then used to calculate lift and drag coefficients. An expression for drag coefficient, which is a function of parasite drag, induced drag, and aileron drag, is solved from forced excitation response data. Estimates of the parasite drag, curvature of the aileron drag variation, and minimum drag aileron position are produced. Minimum drag is then obtained by repositioning the symmetric aileron. Simulation results are also presented which evaluate the affects of measurement bias and resolution.

  15. Ultra-Wideband Time-Difference-of-Arrival High Resolution 3D Proximity Tracking System

    Science.gov (United States)

    Ni, Jianjun; Arndt, Dickey; Ngo, Phong; Phan, Chau; Dekome, Kent; Dusl, John

    2010-01-01

    This paper describes a research and development effort for a prototype ultra-wideband (UWB) tracking system that is currently under development at NASA Johnson Space Center (JSC). The system is being studied for use in tracking of lunar./Mars rovers and astronauts during early exploration missions when satellite navigation systems are not available. U IATB impulse radio (UWB-IR) technology is exploited in the design and implementation of the prototype location and tracking system. A three-dimensional (3D) proximity tracking prototype design using commercially available UWB products is proposed to implement the Time-Difference- Of-Arrival (TDOA) tracking methodology in this research effort. The TDOA tracking algorithm is utilized for location estimation in the prototype system, not only to exploit the precise time resolution possible with UWB signals, but also to eliminate the need for synchronization between the transmitter and the receiver. Simulations show that the TDOA algorithm can achieve the fine tracking resolution with low noise TDOA estimates for close-in tracking. Field tests demonstrated that this prototype UWB TDOA High Resolution 3D Proximity Tracking System is feasible for providing positioning-awareness information in a 3D space to a robotic control system. This 3D tracking system is developed for a robotic control system in a facility called "Moonyard" at Honeywell Defense & System in Arizona under a Space Act Agreement.

  16. Near-Real time, High Resolution Reservoir Monitoring and Modeling with Micro-earthquake Data

    Science.gov (United States)

    Hutchings, L. J.; Jarpe, S.; Boyle, K. L.; Bonner, B. P.; Viegas, G.; Philson, H.; Statz-Boyer, P.; Majer, E.

    2011-12-01

    We present a micro-earthquake recording and automated processing system along with a methodology to provide near-real time, high resolution reservoir monitoring and modeling. An interactive program for testing micro-earthquake network designs helps identify configurations for optimum accuracy and resolution. We select the Northwest Geysers, California geothermal field to showcase the usefulness of the system. The system's inexpensive recorders requires very little time or expertise to install, and the automated processing requires merely placing flash memory chips (or telemetry) into a computer. Together these make the deployment of a large numbers of sensors feasible and thus rapid, high resolution results possible. Data are arranged into input files for tomography for Vp, Vs, Qp and Qs, and their combinations to provide for interpretation in terms of rock properties. Micro-earthquake source parameters include seismic moments, full moment tensor solutions, stress drops, source durations, radiated energy, and hypocentral locations. The methodology for interpretation is to utilize visualization with GUI analysis to cross compare tomography and source property results along with borehole or other independent information and rock physics to identify reservoir properties. The system can potentially provide information heretofore unattainable or affordable to many small companies, organizations, and countries around the world.

  17. Discrete time interval measurement system: fundamentals, resolution and errors in the measurement of angular vibrations

    International Nuclear Information System (INIS)

    Gómez de León, F C; Meroño Pérez, P A

    2010-01-01

    The traditional method for measuring the velocity and the angular vibration in the shaft of rotating machines using incremental encoders is based on counting the pulses at given time intervals. This method is generically called the time interval measurement system (TIMS). A variant of this method that we have developed in this work consists of measuring the corresponding time of each pulse from the encoder and sampling the signal by means of an A/D converter as if it were an analog signal, that is to say, in discrete time. For this reason, we have denominated this method as the discrete time interval measurement system (DTIMS). This measurement system provides a substantial improvement in the precision and frequency resolution compared with the traditional method of counting pulses. In addition, this method permits modification of the width of some pulses in order to obtain a mark-phase on every lap. This paper explains the theoretical fundamentals of the DTIMS and its application for measuring the angular vibrations of rotating machines. It also displays the required relationship between the sampling rate of the signal, the number of pulses of the encoder and the rotating velocity in order to obtain the required resolution and to delimit the methodological errors in the measurement

  18. Robust high-resolution quantification of time signals encoded by in vivo magnetic resonance spectroscopy

    Science.gov (United States)

    Belkić, Dževad; Belkić, Karen

    2018-01-01

    This paper on molecular imaging emphasizes improving specificity of magnetic resonance spectroscopy (MRS) for early cancer diagnostics by high-resolution data analysis. Sensitivity of magnetic resonance imaging (MRI) is excellent, but specificity is insufficient. Specificity is improved with MRS by going beyond morphology to assess the biochemical content of tissue. This is contingent upon accurate data quantification of diagnostically relevant biomolecules. Quantification is spectral analysis which reconstructs chemical shifts, amplitudes and relaxation times of metabolites. Chemical shifts inform on electronic shielding of resonating nuclei bound to different molecular compounds. Oscillation amplitudes in time signals retrieve the abundance of MR sensitive nuclei whose number is proportional to metabolite concentrations. Transverse relaxation times, the reciprocal of decay probabilities of resonances, arise from spin-spin coupling and reflect local field inhomogeneities. In MRS single voxels are used. For volumetric coverage, multi-voxels are employed within a hybrid of MRS and MRI called magnetic resonance spectroscopic imaging (MRSI). Common to MRS and MRSI is encoding of time signals and subsequent spectral analysis. Encoded data do not provide direct clinical information. Spectral analysis of time signals can yield the quantitative information, of which metabolite concentrations are the most clinically important. This information is equivocal with standard data analysis through the non-parametric, low-resolution fast Fourier transform and post-processing via fitting. By applying the fast Padé transform (FPT) with high-resolution, noise suppression and exact quantification via quantum mechanical signal processing, advances are made, presented herein, focusing on four areas of critical public health importance: brain, prostate, breast and ovarian cancers.

  19. Calculation of upper esophageal sphincter restitution time from high resolution manometry data using machine learning.

    Science.gov (United States)

    Jungheim, Michael; Busche, Andre; Miller, Simone; Schilling, Nicolas; Schmidt-Thieme, Lars; Ptok, Martin

    2016-10-15

    After swallowing, the upper esophageal sphincter (UES) needs a certain amount of time to return from maximum pressure to the resting condition. Disturbances of sphincter function not only during the swallowing process but also in this phase of pressure restitution may lead to globus sensation or dysphagia. Since UES pressures do not decrease in a linear or asymptotic manner, it is difficult to determine the exact time when the resting pressure is reached, even when using high resolution manometry (HRM). To overcome this problem a Machine Learning model was established to objectively determine the UES restitution time (RT) and moreover to collect physiological data on sphincter function after swallowing. HRM-data of 15 healthy participants performing 10 swallows each were included. After manual annotation of the RT interval by two swallowing experts, data were transferred to the Machine Learning model, which applied a sequence labeling modeling approach based on logistic regression to learn and objectivize the characteristics of all swallows. Individually computed RT values were then compared with the annotated values. Estimates of the RT were generated by the Machine Learning model for all 150 swallows. When annotated by swallowing experts mean RT of 11.16s±5.7 (SD) and 10.04s±5.74 were determined respectively, compared to model-generated values from 8.91s±3.71 to 10.87s±4.68 depending on model selection. The correlation score for the annotated RT of both examiners was 0.76 and 0.63 to 0.68 for comparison of model predicted values. Restitution time represents an important physiologic swallowing parameter not previously considered in HRM-studies of the UES, especially since disturbances of UES restitution may increase the risk of aspiration. The data presented here show that it takes approximately 9 to 11s for the UES to come to rest after swallowing. Based on maximal RT values, we demonstrate that an interval of 25-30s in between swallows is necessary until the

  20. Design and Performance of A High Resolution Micro-Spec: An Integrated Sub-Millimeter Spectrometer

    Science.gov (United States)

    Barrentine, Emily M.; Cataldo, Giuseppe; Brown, Ari D.; Ehsan, Negar; Noroozian, Omid; Stevenson, Thomas R.; U-Yen, Kongpop; Wollack, Edward J.; Moseley, S. Harvey

    2016-01-01

    Micro-Spec is a compact sub-millimeter (approximately 100 GHz--1:1 THz) spectrometer which uses low loss superconducting microstrip transmission lines and a single-crystal silicon dielectric to integrate all of the components of a diffraction grating spectrometer onto a single chip. We have already successfully evaluated the performance of a prototype Micro-Spec, with spectral resolving power, R=64. Here we present our progress towards developing a higher resolution Micro-Spec, which would enable the first science returns in a balloon flight version of this instrument. We describe modifications to the design in scaling from a R=64 to a R=256 instrument, as well as the ultimate performance limits and design concerns when scaling this instrument to higher resolutions.

  1. Timing performances and edge effects of detectors worked from 6-in. silicon slices

    International Nuclear Information System (INIS)

    Aiello, S.; Anzalone, A.; Cardella, G.; Cavallaro, Sl.; De Filippo, E.; Di Pietro, A.; Femino, S.; Geraci, M.; Giustolisi, F.; Guazzoni, P.; Iacono Manno, M.; Lanzalone, G.; Lanzano, G.; Lo Nigro, S.; Musumarra, A.; Pagano, A.; Papa, M.; Pirrone, S.; Politi, G.; Porto, F.; Rizzo, F.; Sambataro, S.; Sperduto, M.L.; Sutera, C.; Zetta, L.

    1997-01-01

    Prototypes of new passivated implanted planar silicon detectors, obtained for the first time from 6 in. silicon slices, have been tested. The time and energy resolutions have been studied as a function of the type and energy of the detected particles, in order to test the performances of these detectors for time of flight measurements in the Chimera project. Some problems arising from edge effects observed in double-pad detectors have been solved by using a guard ring. (orig.)

  2. Wide-field time-correlated single photon counting (TCSPC) microscopy with time resolution below the frame exposure time

    Energy Technology Data Exchange (ETDEWEB)

    Hirvonen, Liisa M. [Department of Physics, King' s College London, Strand, London WC2R 2LS (United Kingdom); Petrášek, Zdeněk [Max Planck Institute of Biochemistry, Department of Cellular and Molecular Biophysics, Am Klopferspitz 18, D-82152 Martinsried (Germany); Suhling, Klaus, E-mail: klaus.suhling@kcl.ac.uk [Department of Physics, King' s College London, Strand, London WC2R 2LS (United Kingdom)

    2015-07-01

    Fast frame rate CMOS cameras in combination with photon counting intensifiers can be used for fluorescence imaging with single photon sensitivity at kHz frame rates. We show here how the phosphor decay of the image intensifier can be exploited for accurate timing of photon arrival well below the camera exposure time. This is achieved by taking ratios of the intensity of the photon events in two subsequent frames, and effectively allows wide-field TCSPC. This technique was used for measuring decays of ruthenium compound Ru(dpp) with lifetimes as low as 1 μs with 18.5 μs frame exposure time, including in living HeLa cells, using around 0.1 μW excitation power. We speculate that by using an image intensifier with a faster phosphor decay to match a higher camera frame rate, photon arrival time measurements on the nanosecond time scale could well be possible.

  3. High-performance electronics for time-of-flight PET systems

    International Nuclear Information System (INIS)

    Choong, W-S; Peng, Q; Vu, C Q; Turko, B T; Moses, W W

    2013-01-01

    We have designed and built a high-performance readout electronics system for time-of-flight positron emission tomography (TOF PET) cameras. The electronics architecture is based on the electronics for a commercial whole-body PET camera (Siemens/CPS Cardinal electronics), modified to improve the timing performance. The fundamental contributions in the electronics that can limit the timing resolution include the constant fraction discriminator (CFD), which converts the analog electrical signal from the photo-detector to a digital signal whose leading edge is time-correlated with the input signal, and the time-to-digital converter (TDC), which provides a time stamp for the CFD output. Coincident events are identified by digitally comparing the values of the time stamps. In the Cardinal electronics, the front-end processing electronics are performed by an Analog subsection board, which has two application-specific integrated circuits (ASICs), each servicing a PET block detector module. The ASIC has a built-in CFD and TDC. We found that a significant degradation in the timing resolution comes from the ASIC's CFD and TDC. Therefore, we have designed and built an improved Analog subsection board that replaces the ASIC's CFD and TDC with a high-performance CFD (made with discrete components) and TDC (using the CERN high-performance TDC ASIC). The improved Analog subsection board is used in a custom single-ring LSO-based TOF PET camera. The electronics system achieves a timing resolution of 60 ps FWHM. Prototype TOF detector modules are read out with the electronics system and give coincidence timing resolutions of 259 ps FWHM and 156 ps FWHM for detector modules coupled to LSO and LaBr 3 crystals respectively.

  4. Detecting shifts in gene regulatory networks during time-course experiments at single-time-point temporal resolution.

    Science.gov (United States)

    Takenaka, Yoichi; Seno, Shigeto; Matsuda, Hideo

    2015-10-01

    Comprehensively understanding the dynamics of biological systems is one of the greatest challenges in biology. Vastly improved biological technologies have provided vast amounts of information that must be understood by bioinformatics and systems biology researchers. Gene regulations have been frequently modeled by ordinary differential equations or graphical models based on time-course gene expression profiles. The state-of-the-art computational approaches for analyzing gene regulations assume that their models are same throughout time-course experiments. However, these approaches cannot easily analyze transient changes at a time point, such as diauxic shift. We propose a score that analyzes the gene regulations at each time point. The score is based on the information gains of information criterion values. The method detects the shifts in gene regulatory networks (GRNs) during time-course experiments with single-time-point resolution. The effectiveness of the method is evaluated on the diauxic shift from glucose to lactose in Escherichia coli. Gene regulation shifts were detected at two time points: the first corresponding to the time at which the growth of E. coli ceased and the second corresponding to the end of the experiment, when the nutrient sources (glucose and lactose) had become exhausted. According to these results, the proposed score and method can appropriately detect the time of gene regulation shifts. The method based on the proposed score provides a new tool for analyzing dynamic biological systems. Because the score value indicates the strength of gene regulation at each time point in a gene expression profile, it can potentially infer hidden GRNs from time-course experiments.

  5. New strategy to identify radicals in a time evolving EPR data set by multivariate curve resolution-alternating least squares.

    Science.gov (United States)

    Fadel, Maya Abou; de Juan, Anna; Vezin, Hervé; Duponchel, Ludovic

    2016-12-01

    Electron paramagnetic resonance (EPR) spectroscopy is a powerful technique that is able to characterize radicals formed in kinetic reactions. However, spectral characterization of individual chemical species is often limited or even unmanageable due to the severe kinetic and spectral overlap among species in kinetic processes. Therefore, we applied, for the first time, multivariate curve resolution-alternating least squares (MCR-ALS) method to EPR time evolving data sets to model and characterize the different constituents in a kinetic reaction. Here we demonstrate the advantage of multivariate analysis in the investigation of radicals formed along the kinetic process of hydroxycoumarin in alkaline medium. Multiset analysis of several EPR-monitored kinetic experiments performed in different conditions revealed the individual paramagnetic centres as well as their kinetic profiles. The results obtained by MCR-ALS method demonstrate its prominent potential in analysis of EPR time evolved spectra. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. An experimentally verified model for estimating the distance resolution capability of direct time of flight 3D optical imaging systems

    International Nuclear Information System (INIS)

    Nguyen, K Q K; Fisher, E M D; Walton, A J; Underwood, I

    2013-01-01

    This report introduces a new statistical model for time-resolved photon detection in a generic single-photon-sensitive sensor array. The model is validated by comparing modelled data with experimental data collected on a single-photon avalanche diode sensor array. Data produced by the model are used alongside corresponding experimental data to calculate, for the first time, the effective distance resolution of a pulsed direct time of flight 3D optical imaging system over a range of conditions using four peak-detection algorithms. The relative performance of the algorithms is compared. The model can be used to improve the system design process and inform selection of the optimal peak-detection algorithm. (paper)

  7. Performance of the Lep Time Digitizer (LTD)

    International Nuclear Information System (INIS)

    Berst, J.D.; Colledani, C.; Loukas, D.

    1988-01-01

    Performance of the fastbus digitizer to be used for signal digitizing in the DELPHI detectors is described. Two prototypes, a 128 multihit capability device and a 256 capability device were tested. Test results show that the digitizer works properly. A very good stability is achieved in the range of + 150 mV from the nominal (-2V) supply with the total number of lost hits of the order of 10 -6 either in veto or non veto mode. The optimum clock frequency strongly depends on the gates used as delay elements. With the gates of the first prototype, the optimum frequencies obtained are 117 MHz for the first prototype, and 112 MHz for the second. Output linearity is excellent

  8. Comparative timing measurements of LYSO and LFS-3 to achieve the best time resolution for TOF-PET

    CERN Document Server

    Doroud, K; Zichichi, A; Zuyeuski, R

    2015-01-01

    The best Coincidence Time Resolution (CTR) obtained so far – with very short crystals of 3–5 mm in length – reach values between 100 and 150 ps. Such crystals are not really practical for a TOF PET imaging device, since the sensitivity is quite small for the detection of the 511 keV gammas resulting from a positron annihilation. We present our setup and measurements using 15 mm length crystals; a length we regard as reasonable for a TOF-PET scanner. We have used a new series of Silicon Photo-Multipliers (SiPM) manufactured by Hamamatsu. These are the High Fill Factor (HFF) and Low Cross-Talk (LCT) Multi-Pixel Photon Counters (MPPC). We have compared three different crystals, LFS-3 (supplied by Zecotek) and two samples of LYSO (manufactured by Saint Gobain and CPI). We have obtained an excellent value of 148 ps for the Coincidence Time Resolution (CTR) with two LFS-3 crystals (15 mm long) mounted on each side of a 22Na radioactive source with the HFF-MPPCs at 3.3 V over-voltage. Our results are148 ps obt...

  9. An approach for generating synthetic fine temporal resolution solar radiation time series from hourly gridded datasets

    Directory of Open Access Journals (Sweden)

    Matthew Perry

    2017-06-01

    Full Text Available A tool has been developed to statistically increase the temporal resolution of solar irradiance time series. Fine temporal resolution time series are an important input into the planning process for solar power plants, and lead to increased understanding of the likely short-term variability of solar energy. The approach makes use of the spatial variability of hourly gridded datasets around a location of interest to make inferences about the temporal variability within the hour. The unique characteristics of solar irradiance data are modelled by classifying each hour into a typical weather situation. Low variability situations are modelled using an autoregressive process which is applied to ramps of clear-sky index. High variability situations are modelled as a transition between states of clear sky conditions and different levels of cloud opacity. The methods have been calibrated to Australian conditions using 1 min data from four ground stations for a 10 year period. These stations, together with an independent dataset, have also been used to verify the quality of the results using a number of relevant metrics. The results show that the method generates realistic fine resolution synthetic time series. The synthetic time series correlate well with observed data on monthly and annual timescales as they are constrained to the nearest grid-point value on each hour. The probability distributions of the synthetic and observed global irradiance data are similar, with Kolmogorov-Smirnov test statistic less than 0.04 at each station. The tool could be useful for the estimation of solar power output for integration studies.

  10. Transmission-Line Readout with Good Time and Space Resolutions for Planacon MCP-PMTs

    CERN Document Server

    Tang, F; Byrum, K; Drake, G; Ertley, C; Frisch, H; Genat, J-F; May, E

    2008-01-01

    With commercially-available multi-anode microchannel plate photomultiplier tubes (MCP-PMT) and electronics, resolutions significantly better than 10 psec have been achieved in small systems with a few readout channels[1,2]. For large-scale time-of-flight systems used in particle physics, which may cover tens of square meters, a solution must be found with a manageable number of electronics channels and low total power consumption on the readout electronics without degrading the system timing resolution. We present here the design of a transmission-line readout for a Photonis Planacon MCP-PMT that has these characteristics. The tube, which is 5 cm square, is characterized by signal pulse rise times in the order of 200 psec and transit time spreads (TTS) in the order of 25 psec[1, 2]. The model 85011-011 MCP has 1024 anode pads laid out in an array of 32 by 32 on the back of the tube. The proposed readout is implemented on a Rogers 4350B printed circuit board with 32 parallel 50-ohm transmission lines on 1.6 mm...

  11. On high time-range resolution observations of PMSE: Statistical characteristics

    Science.gov (United States)

    Sommer, Svenja; Chau, Jorge L.; Schult, Carsten

    2016-06-01

    We present observations of polar mesospheric summer echoes (PMSE) with an unprecedented temporal sampling of 2 ms and range resolution down to 75 m. On these time and spatial scales, PMSE exhibit features, like correlation in time and range, that have not been described before. To characterize our high resolution observations, we provide a 4-D statistical model, based on random processes. In this way we can distinguish between geophysical and instrumental effects on our measurements. In our simulations, PMSE is statistically characterized in frequency, angular space, and inverse altitude. With this model, we are able to reproduce our observations on a statistical basis and estimate the intrinsic spectral width of PMSE. For chosen data sets, such values range between 0.5 Hz and 4 Hz (1.4 ms-1 to 11.2 ms-1). Furthermore, we show that apparent oscillations in time and an apparent high speed motion of the mean scattering center are just representations of the random nature of PMSE measurements on short time scales.

  12. High-Resolution Over-the-Horizon Radar Using Time Reversal

    Science.gov (United States)

    2009-12-07

    SUBTITLE 6. AUTHOR(S) 8. PERFORMING ORGANIZATION REPORT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 10. SPONSOR / MONITOR’S ACRONYM(S)9...reversal operator) [21], the MUltiple-SIgnal-Classification ( MUSIC ) algorithm [22], etc. However, besides extensive computation, these methods require a...measurements are performed in the time-domain in an all-digital manner, unlike most of other time reversal experiments done in frequency domain with the

  13. Automatic Near-Real-Time Image Processing Chain for Very High Resolution Optical Satellite Data

    Science.gov (United States)

    Ostir, K.; Cotar, K.; Marsetic, A.; Pehani, P.; Perse, M.; Zaksek, K.; Zaletelj, J.; Rodic, T.

    2015-04-01

    In response to the increasing need for automatic and fast satellite image processing SPACE-SI has developed and implemented a fully automatic image processing chain STORM that performs all processing steps from sensor-corrected optical images (level 1) to web-delivered map-ready images and products without operator's intervention. Initial development was tailored to high resolution RapidEye images, and all crucial and most challenging parts of the planned full processing chain were developed: module for automatic image orthorectification based on a physical sensor model and supported by the algorithm for automatic detection of ground control points (GCPs); atmospheric correction module, topographic corrections module that combines physical approach with Minnaert method and utilizing anisotropic illumination model; and modules for high level products generation. Various parts of the chain were implemented also for WorldView-2, THEOS, Pleiades, SPOT 6, Landsat 5-8, and PROBA-V. Support of full-frame sensor currently in development by SPACE-SI is in plan. The proposed paper focuses on the adaptation of the STORM processing chain to very high resolution multispectral images. The development concentrated on the sub-module for automatic detection of GCPs. The initially implemented two-step algorithm that worked only with rasterized vector roads and delivered GCPs with sub-pixel accuracy for the RapidEye images, was improved with the introduction of a third step: super-fine positioning of each GCP based on a reference raster chip. The added step exploits the high spatial resolution of the reference raster to improve the final matching results and to achieve pixel accuracy also on very high resolution optical satellite data.

  14. CMS electromagnetic calorimeter calibration and timing performance during LHC Run I and future prospects

    CERN Document Server

    Di Marco, Emanuele

    2014-01-01

    The CMS ECAL is a high-resolution, hermetic, and homogeneous electromagnetic calorimeter made of 75,848 scintillating lead tungstate crystals. It relies on precision calibration as well as a stable timing measurement to achieve and maintain its design performance. A set of inter-calibration procedures, in particular utilizing different physics channels, is carried out to normalize the differences in crystal light yield and photodetector response between channels. The timing precision achieved is used in important physics measurements and also allows the study of subtle calorimetric effects, such as the timing response of different crystals belonging to the same electromagnetic shower. The challenges of the different calibration techniques and the performance evolution during LHC Run I, as well as the timing resolution achieved in beam tests and during Run I, will be presented. The impact of the calibration and timing precision on physics is illustrated through the successful quest for the Higgs boson via its...

  15. A 1.6-Gsps High-Resolution Waveform Digitizer Based on a Time-Interleaved Technique

    Science.gov (United States)

    Zhao, Lei; Hu, Xiaofang; Feng, Changqing; Tang, Shaochun; Liu, Shubin; An, Qi

    2013-06-01

    A high-speed and high-resolution Analog-to-Digital Conversion circuit is the crucial part in many physics experiments, data communication, and measurement instrumentation. We present the design and test results on a 1.6-Gsps high-resolution waveform digitizer based on a high-speed AD conversion and time-interleaved technique. Considering the mismatch (gain, offset, and skew) among different ADC channels, we employ real-time correction algorithms integrated in an FPGA to enhance the system performance. In the very high-speed situation, simplification of digital processing algorithms is an important task to guarantee a high processing speed. We proposed a novel correction method based on a fully parallel structure. To achieve good performance, we designed a special jitter-cleaning circuit for the sampling clock and front end coupling circuits for the ADCs, and carefully implemented the hardware circuits to guarantee the signal integrity. Test results indicate that this waveform digitizer achieves a sampling rate of 1.6 Gsps and an ENOB around 11 bits for an input signal from 5 MHz to 150 MHz. The ENOB is still above 10.4 bits for an input up to 300 MHz, with the correction algorithms applied.

  16. eWaterCycle: real time assimilation of massive data streams into a hyper-resolution global hydrological model

    Science.gov (United States)

    Hut, Rolf; Sutanudjaja, Edwin; Drost, Niels; Steele-Dunne, Susan; de Jong, Kor; van Beek, Ludovicus; van de Giesen, Nick; Bierkens, Marc

    2013-04-01

    This research is focused on the ICT challenges involved in assimilating massive remote sensing datasets into a hyper-resolution hydrology model. The development of a hyper-resolution (100m) global hydrological model has recently been put forward as a "Grand Challenge" for the hydrological community. PCR-GLOBWB is a unique hydrological model including lateral flow and groundwater as well as human intervention through water consumption, dams and reservoir operations. Over the past decade, remotely sensed states, parameters and fluxes have become available through satellite observations. Exponential growth can be anticipated in the volume of hydrologically useful remote sensing data given the current plans of JAXA, NASA and ESA with respect to Earth observation satellites. Real time assimilation of these data into a hyper-resolution hydrology model would allow us to constrain the estimated states and fluxes and improve the model forecasts. However, this poses significant hydrological and ICT challenges. This project is a unique collaboration between hydrologists, and the computer scientists of the Netherlands eScience Center. Together, we will explore existing and novel ICT technologies to address the CPU and memory requirements of running the forward model. In addition, we will add data assimilation to this model, requiring streaming, management and processing of massive remote sensing datasets, as well as running the model for large ensembles and performing assimilation on a global scale.

  17. A quenched-flow system for measuring heterogeneous enzyme kinetics with sub-second time resolution

    DEFF Research Database (Denmark)

    Olsen, Johan Pelck; Kari, Jeppe; Borch, Kim

    2017-01-01

    approach to elucidate multi-step reactions is transient (or pre steady-state) kinetics. A key requirement for pre steady-state measurements is good time resolution, and while this has been amply achieved in different commercial instruments, they are generally not applicable to precipitating suspensions...... catalyzed hydrolysis of 2,4-dinitrophenyl acetate (DNPA), and the applicability to heterogeneous reactions was documented by two cellulases (Cel7A and Cel7B) acting on suspensions of microcrystalline cellulose (Avicel) at different loads up to 15 g/l. The results showed distinctive differences between...

  18. High-Resolution Light Transmission Spectroscopy of Nanoparticles in Real Time

    Science.gov (United States)

    Tanner, Carol; Sun, Nan; Deatsch, Alison; Li, Frank; Ruggiero, Steven

    2017-04-01

    As implemented here, Light Transmission Spectroscopy (LTS) is a high-resolution real-time technique for eliminating spectral noise and systematic effects in wide band spectroscopic measurements of nanoparticles. In this work, we combine LTS with spectral inversion for the purpose of characterizing the size, shape, and number of nanoparticles in solution. The apparatus employs a wide-band multi-wavelength light source and grating spectrometers coupled to CCD detectors. The light source ranges from 210 to 2000 nm, and the wavelength dependent light detection system ranges from 200 to 1100 nm with College of Science, Department of Physics, and USDA.

  19. Single photon timing resolution and detection efficiency of the IRST silicon photo-multipliers

    International Nuclear Information System (INIS)

    Collazuol, G.; Ambrosi, G.; Boscardin, M.; Corsi, F.; Dalla Betta, G.F.; Del Guerra, A.; Dinu, N.; Galimberti, M.; Giulietti, D.; Gizzi, L.A.; Labate, L.; Llosa, G.; Marcatili, S.; Morsani, F.; Piemonte, C.; Pozza, A.; Zaccarelli, L.; Zorzi, N.

    2007-01-01

    Silicon photo-multipliers (SiPM) consist in matrices of tiny, passive quenched avalanche photo-diode cells connected in parallel via integrated resistors and operated in Geiger mode. Novel types of SiPM are being developed at FBK-IRST (Trento, Italy). Despite their classical shallow junction n-on-p structure the devices are unique in their enhanced photo-detection efficiency (PDE) for short-wavelengths and in their low level of dark rate and excess noise factor. After a summary of the extensive SiPM characterization we will focus on the study of PDE and the single photon timing resolution

  20. The optimization of the time resolution and the sensitivity in the pulsed nuclear resonance

    International Nuclear Information System (INIS)

    Umathum, R.

    1987-01-01

    The time resolution of pulsed NMR spectrometer and its spectral sensitivity are closely connected together. An important obstacle in the attempt to increase the resolution represents the dead time of the spectrometer. In the present thesis therefore the different contributions to the system dead time and their causes are analyzed and ways to the reduction respectively complete removement of a part of these contributions are indicated. So a duplexer was developed and constructed on the base of a principle novel for the NMR under application of quadrature hybrids which reduces the residual voltage of the sender pulse to less than 1/10 of the hitherto reached value. In this thesis a concept is extensively discussed which allows to generate at constant quality respectively damping constant of the sample circuit and given sender power a larger high frequency field strength than it is possible in the state of the power fitting. It could be shown than also concerning the noise behaviour by the application of the principle of the defined misfit no compromise must be made but it is even facilitated to approach the ideal of the noise fit of the first receiver stage to the sample circuit. (orig./HSI) [de

  1. Electron-optical metrology with femtosecond time resolution (theory and experiment)

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, S V; Vorob' ev, Nikolai S; Greenfield, D E; Lozovoi, V I; Monastyrskii, M A; Serdyuchenko, Yu N; Smirnov, A V; Shchelev, Mikhail Ya [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2013-04-30

    The principles of simultaneous spatial and temporal focusing of photoelectron beams in nonstationary electric fields are theoretically studied and experimentally realised as applied to time-analysing image-converter tubes (ICTs). It is theoretically shown that the use of nonstationary focusing electric fields makes it possible to surpass the theoretical time resolution limit of ICTs (10{sup -4} s) determined for stationary fields by Zavoisky and Fanchenko in the 40s-50s of the last century. The possibility of forming electron packets with an energy of 10-30 KeV and a subfemtosecond duration (below 10{sup -15} s) gives impetus to the development of time-resolved electron diffraction, which is a direct method of investigation of atomic-molecular dynamics in solid and gaseous media. (extreme light fields and their applications)

  2. Performance of a TV white space database with different terrain resolutions and propagation models

    Directory of Open Access Journals (Sweden)

    A. M. Fanan

    2017-11-01

    Full Text Available Cognitive Radio has now become a realistic option for the solution of the spectrum scarcity problem in wireless communication. TV channels (the primary user can be protected from secondary-user interference by accurate prediction of TV White Spaces (TVWS by using appropriate propagation modelling. In this paper we address two related aspects of channel occupancy prediction for cognitive radio. Firstly we investigate the best combination of empirical propagation model and spatial resolution of terrain data for predicting TVWS by examining the performance of three propagation models (Extended-Hata, Davidson-Hata and Egli in the TV band 470 to 790 MHz along with terrain data resolutions of 1000, 100 and 30 m, when compared with a comprehensive set of propagation measurements taken in randomly-selected locations around Hull, UK. Secondly we describe how such models can be integrated into a database-driven tool for cognitive radio channel selection within the TVWS environment.

  3. Distributed UAV-Swarm Real-Time Geomatic Data Collection Under Dynamically Changing Resolution Requirements

    Science.gov (United States)

    Almeida, Miguel; Hildmann, Hanno; Solmaz, Gürkan

    2017-08-01

    Unmanned Aerial Vehicles (UAVs) have been used for reconnaissance and surveillance missions as far back as the Vietnam War, but with the recent rapid increase in autonomy, precision and performance capabilities - and due to the massive reduction in cost and size - UAVs have become pervasive products, available and affordable for the general public. The use cases for UAVs are in the areas of disaster recovery, environmental mapping & protection and increasingly also as extended eyes and ears of civil security forces such as fire-fighters and emergency response units. In this paper we present a swarm algorithm that enables a fleet of autonomous UAVs to collectively perform sensing tasks related to environmental and rescue operations and to dynamically adapt to e.g. changing resolution requirements. We discuss the hardware used to build our own drones and the settings under which we validate the proposed approach.

  4. DISTRIBUTED UAV-SWARM-BASED REAL-TIME GEOMATIC DATA COLLECTION UNDER DYNAMICALLY CHANGING RESOLUTION REQUIREMENTS

    Directory of Open Access Journals (Sweden)

    M. Almeida

    2017-08-01

    Full Text Available Unmanned Aerial Vehicles (UAVs have been used for reconnaissance and surveillance missions as far back as the Vietnam War, but with the recent rapid increase in autonomy, precision and performance capabilities – and due to the massive reduction in cost and size – UAVs have become pervasive products, available and affordable for the general public. The use cases for UAVs are in the areas of disaster recovery, environmental mapping & protection and increasingly also as extended eyes and ears of civil security forces such as fire-fighters and emergency response units. In this paper we present a swarm algorithm that enables a fleet of autonomous UAVs to collectively perform sensing tasks related to environmental and rescue operations and to dynamically adapt to e.g. changing resolution requirements. We discuss the hardware used to build our own drones and the settings under which we validate the proposed approach.

  5. High spatial and temporal resolution retrospective cine cardiovascular magnetic resonance from shortened free breathing real-time acquisitions.

    Science.gov (United States)

    Xue, Hui; Kellman, Peter; Larocca, Gina; Arai, Andrew E; Hansen, Michael S

    2013-11-14

    Cine cardiovascular magnetic resonance (CMR) is challenging in patients who cannot perform repeated breath holds. Real-time, free-breathing acquisition is an alternative, but image quality is typically inferior. There is a clinical need for techniques that achieve similar image quality to the segmented cine using a free breathing acquisition. Previously, high quality retrospectively gated cine images have been reconstructed from real-time acquisitions using parallel imaging and motion correction. These methods had limited clinical applicability due to lengthy acquisitions and volumetric measurements obtained with such methods have not previously been evaluated systematically. This study introduces a new retrospective reconstruction scheme for real-time cine imaging which aims to shorten the required acquisition. A real-time acquisition of 16-20s per acquired slice was inputted into a retrospective cine reconstruction algorithm, which employed non-rigid registration to remove respiratory motion and SPIRiT non-linear reconstruction with temporal regularization to fill in missing data. The algorithm was used to reconstruct cine loops with high spatial (1.3-1.8 × 1.8-2.1 mm²) and temporal resolution (retrospectively gated, 30 cardiac phases, temporal resolution 34.3 ± 9.1 ms). Validation was performed in 15 healthy volunteers using two different acquisition resolutions (256 × 144/192 × 128 matrix sizes). For each subject, 9 to 12 short axis and 3 long axis slices were imaged with both segmented and real-time acquisitions. The retrospectively reconstructed real-time cine images were compared to a traditional segmented breath-held acquisition in terms of image quality scores. Image quality scoring was performed by two experts using a scale between 1 and 5 (poor to good). For every subject, LAX and three SAX slices were selected and reviewed in the random order. The reviewers were blinded to the reconstruction approach and acquisition protocols and

  6. An ion trap time-of-flight mass spectrometer with high mass resolution for cold trapped ion experiments

    Science.gov (United States)

    Schmid, P. C.; Greenberg, J.; Miller, M. I.; Loeffler, K.; Lewandowski, H. J.

    2017-12-01

    Trapping molecular ions that have been sympathetically cooled with laser-cooled atomic ions is a useful platform for exploring cold ion chemistry. We designed and characterized a new experimental apparatus for probing chemical reaction dynamics between molecular cations and neutral radicals at temperatures below 1 K. The ions are trapped in a linear quadrupole radio-frequency trap and sympathetically cooled by co-trapped, laser-cooled, atomic ions. The ion trap is coupled to a time-of-flight mass spectrometer to readily identify product ion species and to accurately determine trapped ion numbers. We discuss, and present in detail, the design of this ion trap time-of-flight mass spectrometer and the electronics required for driving the trap and mass spectrometer. Furthermore, we measure the performance of this system, which yields mass resolutions of m/Δm ≥ 1100 over a wide mass range, and discuss its relevance for future measurements in chemical reaction kinetics and dynamics.

  7. Dynamics of Transformation from Platinum Icosahedral Nanoparticles to Larger FCC Crystal at Millisecond Time Resolution

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wenpei [Univ. of Illinois at Urbana-Champaign, IL (United States). Dept. of Materials Science and Engineering and Fredrick Seitz Materials Research Lab.; Wu, Jianbo [Univ. of Illinois at Urbana-Champaign, IL (United States). Dept. of Materials Science and Engineering, Fredrick Seitz Materials Research Lab. and Dept. of Chemical and Biomolecular Engineering; Shanghai Jiao Tong Univ. (China). School of Materials Science and Engineering; Yoon, Aram [Univ. of Illinois at Urbana-Champaign, IL (United States). Dept. of Materials Science and Engineering and Fredrick Seitz Materials Research Lab.; Lu, Ping [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Qi, Liang [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Materials Science and Engineering; Wen, Jianguo [Argonne National Lab. (ANL), Argonne, IL (United States). Center for Nanoscale Materials and Electron Microscopy Center; Miller, Dean J. [Argonne National Lab. (ANL), Argonne, IL (United States). Center for Nanoscale Materials and Electron Microscopy Center; Mabon, James C. [Univ. of Illinois at Urbana-Champaign, IL (United States). Fredrick Seitz Materials Research Lab.; Wilson, William L. [Univ. of Illinois at Urbana-Champaign, IL (United States). Dept. of Materials Science and Engineering and Fredrick Seitz Materials Research Lab.; Yang, Hong [Univ. of Illinois at Urbana-Champaign, IL (United States). Dept. of Chemical and Biomolecular Engineering; Zuo, Jian-Min [Univ. of Illinois at Urbana-Champaign, IL (United States). Dept. of Materials Science and Engineering and Fredrick Seitz Materials Research Lab.

    2017-12-08

    Atomic motion at grain boundaries is essential to microstructure development, growth and stability of catalysts and other nanostructured materials. However, boundary atomic motion is often too fast to observe in a conventional transmission electron microscope (TEM) and too slow for ultrafast electron microscopy. We report on the entire transformation process of strained Pt icosahedral nanoparticles (ICNPs) into larger FCC crystals, captured at 2.5 ms time resolution using a fast electron camera. Results show slow diffusive dislocation motion at nm/s inside ICNPs and fast surface transformation at μm/s. By characterizing nanoparticle strain, we show that the fast transformation is driven by inhomogeneous surface stress. And interaction with pre-existing defects led to the slowdown of the transformation front inside the nanoparticles. Particle coalescence, assisted by oxygen-induced surface migration at T ≥ 300°C, also played a critical role. Thus by studying transformation in the Pt ICNPs at high time and spatial resolution, we obtain critical insights into the transformation mechanisms in strained Pt nanoparticles.

  8. Time-efficient, high-resolution, whole brain three-dimensional macromolecular proton fraction mapping.

    Science.gov (United States)

    Yarnykh, Vasily L

    2016-05-01

    Macromolecular proton fraction (MPF) mapping is a quantitative MRI method that reconstructs parametric maps of a relative amount of macromolecular protons causing the magnetization transfer (MT) effect and provides a biomarker of myelination in neural tissues. This study aimed to develop a high-resolution whole brain MPF mapping technique using a minimal number of source images for scan time reduction. The described technique was based on replacement of an actually acquired reference image without MT saturation by a synthetic one reconstructed from R1 and proton density maps, thus requiring only three source images. This approach enabled whole brain three-dimensional MPF mapping with isotropic 1.25 × 1.25 × 1.25 mm(3) voxel size and a scan time of 20 min. The synthetic reference method was validated against standard MPF mapping with acquired reference images based on data from eight healthy subjects. Mean MPF values in segmented white and gray matter appeared in close agreement with no significant bias and small within-subject coefficients of variation (maps demonstrated sharp white-gray matter contrast and clear visualization of anatomical details, including gray matter structures with high iron content. The proposed synthetic reference method improves resolution of MPF mapping and combines accurate MPF measurements with unique neuroanatomical contrast features. © 2015 Wiley Periodicals, Inc.

  9. Time-optimized high-resolution readout-segmented diffusion tensor imaging.

    Directory of Open Access Journals (Sweden)

    Gernot Reishofer

    Full Text Available Readout-segmented echo planar imaging with 2D navigator-based reacquisition is an uprising technique enabling the sampling of high-resolution diffusion images with reduced susceptibility artifacts. However, low signal from the small voxels and long scan times hamper the clinical applicability. Therefore, we introduce a regularization algorithm based on total variation that is applied directly on the entire diffusion tensor. The spatially varying regularization parameter is determined automatically dependent on spatial variations in signal-to-noise ratio thus, avoiding over- or under-regularization. Information about the noise distribution in the diffusion tensor is extracted from the diffusion weighted images by means of complex independent component analysis. Moreover, the combination of those features enables processing of the diffusion data absolutely user independent. Tractography from in vivo data and from a software phantom demonstrate the advantage of the spatially varying regularization compared to un-regularized data with respect to parameters relevant for fiber-tracking such as Mean Fiber Length, Track Count, Volume and Voxel Count. Specifically, for in vivo data findings suggest that tractography results from the regularized diffusion tensor based on one measurement (16 min generates results comparable to the un-regularized data with three averages (48 min. This significant reduction in scan time renders high resolution (1 × 1 × 2.5 mm(3 diffusion tensor imaging of the entire brain applicable in a clinical context.

  10. A novel capacitive absolute positioning sensor based on time grating with nanometer resolution

    Science.gov (United States)

    Pu, Hongji; Liu, Hongzhong; Liu, Xiaokang; Peng, Kai; Yu, Zhicheng

    2018-05-01

    The present work proposes a novel capacitive absolute positioning sensor based on time grating. The sensor includes a fine incremental-displacement measurement component combined with a coarse absolute-position measurement component to obtain high-resolution absolute positioning measurements. A single row type sensor was proposed to achieve fine displacement measurement, which combines the two electrode rows of a previously proposed double-row type capacitive displacement sensor based on time grating into a single row. To achieve absolute positioning measurement, the coarse measurement component is designed as a single-row type displacement sensor employing a single spatial period over the entire measurement range. In addition, this component employs a rectangular induction electrode and four groups of orthogonal discrete excitation electrodes with half-sinusoidal envelope shapes, which were formed by alternately extending the rectangular electrodes of the fine measurement component. The fine and coarse measurement components are tightly integrated to form a compact absolute positioning sensor. A prototype sensor was manufactured using printed circuit board technology for testing and optimization of the design in conjunction with simulations. Experimental results show that the prototype sensor achieves a ±300 nm measurement accuracy with a 1 nm resolution over a displacement range of 200 mm when employing error compensation. The proposed sensor is an excellent alternative to presently available long-range absolute nanometrology sensors owing to its low cost, simple structure, and ease of manufacturing.

  11. APES: Acute Precipitating Electron Spectrometer - A High Time Resolution Monodirectional Magnetic Deflection Electron Spectrometer

    Science.gov (United States)

    Michell, R. G.; Samara, M.; Grubbs, G., II; Ogasawara, K.; Miller, G.; Trevino, J. A.; Webster, J.; Stange, J.

    2016-01-01

    We present a description of the Acute Precipitating Electron Spectrometer (APES) that was designed and built for the Ground-to-Rocket Electron Electrodynamics Correlative Experiment (GREECE) auroral sounding rocket mission. The purpose was to measure the precipitating electron spectrum with high time resolution, on the order of milliseconds. The trade-off made in order to achieve high time resolution was to limit the aperture to only one look direction. The energy selection was done by using a permanent magnet to separate the incoming electrons, such that the different energies would fall onto different regions of the microchannel plate and therefore be detected by different anodes. A rectangular microchannel plate (MCP) was used (15 mm x 100 mm), and there was a total of 50 discrete anodes under the MCP, each one 15 mm x 1.5 mm, with a 0.5 mm spacing between anodes. The target energy range of APES was 200 eV to 30 keV.

  12. 'Moving source': test realization at VEPP-3 of a diffraction experiment with nanosecond time resolution

    CERN Document Server

    Mishnev, S I; Fedotov, M G; Tolochko, B P

    2000-01-01

    The purpose of this work is a demonstration of the basic possibility of the practical realization of the 'moving source' idea for X-ray diffraction with nanosecond time resolution. The idea of 'moving source' was published earlier. The principle of this idea is: a quick change of electron trajectory by the kicker is responsible for a quick change of direction of synchrotron radiation (SR). In such a way a 'moving source' can be created. Using the 'moving source' it is possible to scan a sample with the SR beam. As a result, diffraction with nanoseconds time resolution can be achieved . The experiment at the VEPP-3 storage ring has confirmed such a possibility. The following answers to the main questions were received: (1) SR intensities are enough for obtaining satisfactory statistics from one bunch (2) it is possible to realize synchronization of an impact with the motion of electrons in the storage ring and with the systems of image registration ; (3) it is possible to compensate the betatron oscillation wh...

  13. Global system for hydrological monitoring and forecasting in real time at high resolution

    Science.gov (United States)

    Ortiz, Enrique; De Michele, Carlo; Todini, Ezio; Cifres, Enrique

    2016-04-01

    This project presented at the EGU 2016 born of solidarity and the need to dignify the most disadvantaged people living in the poorest countries (Africa, South America and Asia, which are continually exposed to changes in the hydrologic cycle suffering events of large floods and/or long periods of droughts. It is also a special year this 2016, Year of Mercy, in which we must engage with the most disadvantaged of our Planet (Gaia) making available to them what we do professionally and scientifically. The project called "Global system for hydrological monitoring and forecasting in real time at high resolution" is Non-Profit and aims to provide at global high resolution (1km2) hydrological monitoring and forecasting in real time and continuously coupling Weather Forecast of Global Circulation Models, such us GFS-0.25° (Deterministic and Ensembles Run) forcing a physically based distributed hydrological model computationally efficient, such as the latest version extended of TOPKAPI model, named TOPKAPI-eXtended. Finally using the MCP approach for the proper use of ensembles for Predictive Uncertainty assessment essentially based on a multiple regression in the Normal space, can be easily extended to use ensembles to represent the local (in time) smaller or larger conditional predictive uncertainty, as a function of the ensemble spread. In this way, each prediction in time accounts for both the predictive uncertainty of the ensemble mean and that of the ensemble spread. To perform a continuous hydrological modeling with TOPKAPI-X model and have hot start of hydrological status of watersheds, the system assimilated products of rainfall and temperature derived from remote sensing, such as product 3B42RT of TRMM NASA and others.The system will be integrated into a Decision Support System (DSS) platform, based on geographical data. The DSS is a web application (For Pc, Tablet/Mobile phone): It does not need installation (all you need is a web browser and an internet

  14. Pulse radiolysis with (sub) nanosecond time resolution using a 3 MV electron accelerator

    International Nuclear Information System (INIS)

    Luthjens, L.H.

    1986-01-01

    In this thesis the development of equipment for pulse radiolysis is described and the application of the technique to time-resolved measurements of the fluorescence emission of excited states formed after irradiation of some alkanes is dealt with. A review is given of the development of the pulsed 3MV Van de Graaf electron accelerator for the generation of subnanosecond electron beam pulses and of the development of the equipment for optical detection as accomplished by the author. The initial stage of a further development for shorter pulses and higher time resolution is briefly discussed. A collection of papers on the development of apparatus and a collection of papers dealing with the results obtained from measurements of the fluorescence of excited states, formed by the recombination of electrons and ions in irradiated alkanes such as cyclohexane and the decalines, are included. (Auth.)

  15. An Improvement on Space Focusing Resolution in Two-Field Time-of-Flight Mass Spectrometers

    International Nuclear Information System (INIS)

    Yildirim, M.; Aydin, R.; Akin, U.; Kilic, H. S.; Sise, O.; Ulu, M.; Dogan, M.

    2007-01-01

    Time-of-Flight Mass Spectrometer (TOFMS) is a sophisticated device for the mass selective analysis of a variety of samples. The main limitation on TOFMS technique is the obtainable resolution where the two main limiting factors are the initial space and energy spread of particles created in ionization region. Similar charged particles starting at different points will reach the detector at different times. So, this problem makes space focusing is very important subject. We have presented principles of two-fields TOFMS with second-order space focusing both using analytical methods and ray-tracing simulation. This work aims understanding of ion optical system clearly and gives hint of expectation for future developments

  16. Magnetic marker monitoring: high resolution real-time tracking of oral solid dosage forms in the gastrointestinal tract.

    Science.gov (United States)

    Weitschies, Werner; Blume, Henning; Mönnikes, Hubert

    2010-01-01

    Knowledge about the performance of dosage forms in the gastrointestinal tract is essential for the development of new oral delivery systems, as well as for the choice of the optimal formulation technology. Magnetic Marker Monitoring (MMM) is an imaging technology for the investigation of the behaviour of solid oral dosage forms within the gastrointestinal tract, which is based on the labelling of solid dosage forms as a magnetic dipole and determination of the location, orientation and strength of the dipole after oral administration using measurement equipment and localization methods that are established in biomagnetism. MMM enables the investigation of the performance of solid dosage forms in the gastrointestinal tract with a temporal resolution in the range of a few milliseconds and a spatial resolution in 3D in the range of some millimetres. Thereby, MMM provides real-time tracking of dosage forms in the gastrointestinal tract. MMM is also suitable for the determination of dosage form disintegration and for quantitative measurement of in vivo drug release in case of appropriate extended release dosage forms like hydrogel-forming matrix tablets. The combination of MMM with pharmacokinetic measurements (pharmacomagnetography) enables the determination of in vitro-in vivo correlations (IVIC) and the delineation of absorption sites in the gastrointestinal tract. Copyright 2009 Elsevier B.V. All rights reserved.

  17. FastTracker performance using the new“Variable Resolution Associative Memory”for Atlas

    CERN Document Server

    Iizawa, T; The ATLAS collaboration

    2012-01-01

    We report on performances of the new “variable resolution Associative Memory (AM)”applied to the reconstruction of top pair events buried in a large pile-up environment using the ATLAS detector. The AM is a VLSI processor for pattern recognition based on Content Addressable Memory (CAM) architecture. The AM is optimized for on-line track finding in high-energy physics experiments. Pattern matching is carried out by finding track candidates in coarse resolution “roads”. A large AM bank stores all trajectories of interest, called “patterns”, for a given detector resolution. The AM extracts roads compatible with a given event during detector read-out. Two important variables characterize the quality of the AM bank: its “coverage” (the fraction of tracks that match at least one pattern in the bank) and the level of “fake candidates” (roughly proportional to the number of patterns in the bank). As the luminosity increases, the fake rate increases rapidly because of the increased silicon occupan...

  18. Performances of a specific denoising wavelet process for high-resolution gamma imaging

    Science.gov (United States)

    Pousse, Annie; Dornier, Christophe; Parmentier, Michel; Kastler, Bruno; Chavanelle, Jerome

    2004-02-01

    Due to its functional capabilities, gamma imaging is an interesting tool for medical diagnosis. Recent developments lead to improved intrinsic resolution. However this gain is impaired by the poor activity detected and the Poissonian feature of gamma ray emission. High resolution gamma images are grainy. This is a real nuisance for detecting cold nodules in an emitting organ. A specific translation wavelet filter which takes into account the Poissonian feature of noise, has been developed in order to improve the diagnostic capabilities of radioisotopic high resolution images. Monte Carlo simulations of a hot thyroid phantom in which cold spheres, 3-7 mm in diameter, could be included were performed. The loss of activity induced by cold nodules was determined on filtered images by using catchment basins determination. On the original images, only 5-7 mm cold spheres were clearly visible. On filtered images, 3 and 4 mm spheres were put in prominent. The limit of the developed filter is approximately the detection of 3 mm spherical cold nodule in acquisition and activity conditions which mimic a thyroid examination. Furthermore, no disturbing artifacts are generated. It is therefore a powerful tool for detecting small cold nodules in a gamma emitting medium.

  19. Femtosecond resolution timing jitter correction on a TW scale Ti:sapphire laser system for FEL pump-probe experiments.

    Science.gov (United States)

    Csatari Divall, Marta; Mutter, Patrick; Divall, Edwin J; Hauri, Christoph P

    2015-11-16

    Intense ultrashort pulse lasers are used for fs resolution pump-probe experiments more and more at large scale facilities, such as free electron lasers (FEL). Measurement of the arrival time of the laser pulses and stabilization to the machine or other sub-systems on the target, is crucial for high time-resolution measurements. In this work we report on a single shot, spectrally resolved, non-collinear cross-correlator with sub-fs resolution. With a feedback applied we keep the output of the TW class Ti:sapphire amplifier chain in time with the seed oscillator to ~3 fs RMS level for several hours. This is well below the typical pulse duration used at FELs and supports fs resolution pump-probe experiments. Short term jitter and long term timing drift measurements are presented. Applicability to other wavelengths and integration into the timing infrastructure of the FEL are also covered to show the full potential of the device.

  20. Classification of Small-Scale Eucalyptus Plantations Based on NDVI Time Series Obtained from Multiple High-Resolution Datasets

    Directory of Open Access Journals (Sweden)

    Hailang Qiao

    2016-02-01

    Full Text Available Eucalyptus, a short-rotation plantation, has been expanding rapidly in southeast China in recent years owing to its short growth cycle and high yield of wood. Effective identification of eucalyptus, therefore, is important for monitoring land use changes and investigating environmental quality. For this article, we used remote sensing images over 15 years (one per year with a 30-m spatial resolution, including Landsat 5 thematic mapper images, Landsat 7-enhanced thematic mapper images, and HJ 1A/1B images. These data were used to construct a 15-year Normalized Difference Vegetation Index (NDVI time series for several cities in Guangdong Province, China. Eucalyptus reference NDVI time series sub-sequences were acquired, including one-year-long and two-year-long growing periods, using invested eucalyptus samples in the study region. In order to compensate for the discontinuity of the NDVI time series that is a consequence of the relatively coarse temporal resolution, we developed an inverted triangle area methodology. Using this methodology, the images were classified on the basis of the matching degree of the NDVI time series and two reference NDVI time series sub-sequences during the growing period of the eucalyptus rotations. Three additional methodologies (Bounding Envelope, City Block, and Standardized Euclidian Distance were also tested and used as a comparison group. Threshold coefficients for the algorithms were adjusted using commission–omission error criteria. The results show that the triangle area methodology out-performed the other methodologies in classifying eucalyptus plantations. Threshold coefficients and an optimal discriminant function were determined using a mosaic photograph that had been taken by an unmanned aerial vehicle platform. Good stability was found as we performed further validation using multiple-year data from the high-resolution Gaofen Satellite 1 (GF-1 observations of larger regions. Eucalyptus planting dates

  1. FAST INTEGER AMBIGUITY RESOLUTION IN GPS KINEMATIC POSITIONING USING LEFT NULL SPACE AND MULTI-TIME (INVERSE PAIRED CHOLESKY DECORRELATION

    Directory of Open Access Journals (Sweden)

    Rong Duan

    Full Text Available Aiming at the problems that huge amount of computation in ambiguity resolution with multiple epochs and high-order matrix inversion occurred in the GPS kinematic relative positioning, a modified algorithm for fast integer ambiguity resolution is proposed. Firstly, Singular Value Decomposition (SVD is applied to construct the left null space matrix in order to eliminate the baselines components, which is able to separate ambiguity parameters from the position parameters efficiently. Kalman filter is applied only to estimate the ambiguity parameters so that the real-time ambiguity float solution is obtained. Then, sorting and multi-time (inverse paired Cholesky decomposition are adopted for decorrelation of ambiguity. After diagonal elements preprocessing and diagonal elements sorting according to the results of Cholesky decomposition, the efficiency of decomposition and decorrelation is improved. Lastly, the integer search algorithm implemented in LAMBDA method is used for searching the integer ambiguity. To verify the validity and efficacy of the proposed algorithm, static and kinematic tests are carried out. Experimental results show that this algorithm has good performance of decorrelation and precision of float solution, with computation speed also increased effectively. The final positioning accuracy result with static baseline error less than 1 cm and kinematic error less than 2 cm, which indicates that it can be used for fast kinematic positioning of high precision carrier.

  2. Real-time Precise Point Positioning with Ambiguity Resolution for Geosciences

    Science.gov (United States)

    Geng, J.; Meng, X.; Teferle, F. N.; Dodson, A. H.; Ge, M.; Shi, C.; Liu, J.

    2009-04-01

    Real-time provision of information on large scale crustal deformation during an earthquake can be crucial in assessing property damage and managing relief operations. Moreover, such a real-time monitoring system may even lead to the accurate prediction of earthquakes in future and help the subsequent studies on the mechanism involved. During the past two decades, Global Positioning System (GPS) measurements have been extensively applied to investigate such processes in the geosciences. Precise point positioning (PPP) using GPS based on single stations can achieve comparable accuracies to conventional relative positioning, when precise satellite orbits and clocks, and Earth rotation products are used. Thus, PPP does not need any reference stations to achieve high positioning accuracy, e.g. at the millimetre level in static and centimetre level in kinematic applications. This has both technical and economic advantages and may be the only feasible option in some specific applications such as Tsunami early warning systems. However, unlike relative positioning, PPP suffers from unresolved integer ambiguities, which prevented further accuracy improvements within short observation periods or in real-time. On account of the great potential of PPP, we developed a prototype real-time PPP system which also employs ambiguity resolution at a single station. This development is based on the PANDA (Positioning And Navigation Data Analyst) software, which was originally developed at Wuhan University in China, and has been significantly refined by the authors. To assess this system, about 30 stations from the EUREF Permanent Network Internet Protocol (EUREF-IP) pilot project are used to produce the real-time satellite clocks, with satellite orbits and Earth rotation parameters (ERP) fixed to the predicted part of the IGS (International GNSS Service) ultra-rapid products. This is followed by the estimation of the uncalibrated hardware delays (UHD), which are crucial in resolving the

  3. Performance of a high resolution, high flux density SGM undulator beamline at the ALS

    International Nuclear Information System (INIS)

    Warwick, T.; Heimann, P.; Mossessian, D.; McKinney, W.; Padmore, H.

    1994-01-01

    The performance of ALS beamline 7.0 is described. This is an integrated system for delivering radiation from a 5cm period undulator to spectroscopy and microscopy experiments across the range of photon energies from 60eV to 1200eV. The beamline is engineered to deliver the highest possible flux, with negligible deformation of the optic surfaces due to heating. Two experiment stations are served with rapid interchangeability. We report on the measured operational parameters, the resolution and flux delivered, and the refocus of the light into a small spot at the experiment

  4. A tutorial on the construction of high-performance resolution/paramodulation systems

    Energy Technology Data Exchange (ETDEWEB)

    Butler, R.; Overbeek, R.

    1990-09-01

    Over the past 25 years, researchers have written numerous deduction systems based on resolution and paramodulation. Of these systems, a very few have been capable of generating and maintaining a formula database'' containing more than just a few thousand clauses. These few systems were used to explore mechanisms for rapidly extracting limited subsets of relevant'' clauses. We have written this tutorial to reflect some of the best ideas that have emerged and to cast them in a form that makes them easily accessible to students wishing to write their own high-performance systems. 4 refs.

  5. Development and Operation of a High Resolution Positron Emission Tomography System to Perform Metabolic Studies on Small Animals.

    Science.gov (United States)

    Hogan, Matthew John

    A positron emission tomography system designed to perform high resolution imaging of small volumes has been characterized. Two large area planar detectors, used to detect the annihilation gamma rays, formed a large aperture stationary positron camera. The detectors were multiwire proportional chambers coupled to high density lead stack converters. Detector efficiency was 8%. The coincidence resolving time was 500 nsec. The maximum system sensitivity was 60 cps/(mu)Ci for a solid angle of acceptance of 0.74(pi) St. The maximum useful coincidence count rate was 1500 cps and was limited by electronic dead time. Image reconstruction was done by performing a 3-dimensional deconvolution using Fourier transform methods. Noise propagation during reconstruction was minimized by choosing a 'minimum norm' reconstructed image. In the stationary detector system (with a limited angle of acceptance for coincident events) statistical uncertainty in the data limited reconstruction in the direction normal to the detector surfaces. Data from a rotated phantom showed that detector rotation will correct this problem. Resolution was 4 mm in planes parallel to the detectors and (TURN)15 mm in the normal direction. Compton scattering of gamma rays within a source distribution was investigated using both simulated and measured data. Attenuation due to scatter was as high as 60%. For small volume imaging the Compton background was identified and an approximate correction was performed. A semiquantitative blood flow measurement to bone in the leg of a cat using the ('18)F('-) ion was performed. The results were comparable to investigations using more conventional techniques. Qualitative scans using ('18)F labelled deoxy -D-glucose to assess brain glucose metabolism in a rhesus monkey were also performed.

  6. Single-pixel three-dimensional imaging with time-based depth resolution

    Science.gov (United States)

    Sun, Ming-Jie; Edgar, Matthew P.; Gibson, Graham M.; Sun, Baoqing; Radwell, Neal; Lamb, Robert; Padgett, Miles J.

    2016-07-01

    Time-of-flight three-dimensional imaging is an important tool for applications such as object recognition and remote sensing. Conventional time-of-flight three-dimensional imaging systems frequently use a raster scanned laser to measure the range of each pixel in the scene sequentially. Here we show a modified time-of-flight three-dimensional imaging system, which can use compressed sensing techniques to reduce acquisition times, whilst distributing the optical illumination over the full field of view. Our system is based on a single-pixel camera using short-pulsed structured illumination and a high-speed photodiode, and is capable of reconstructing 128 × 128-pixel resolution three-dimensional scenes to an accuracy of ~3 mm at a range of ~5 m. Furthermore, by using a compressive sampling strategy, we demonstrate continuous real-time three-dimensional video with a frame-rate up to 12 Hz. The simplicity of the system hardware could enable low-cost three-dimensional imaging devices for precision ranging at wavelengths beyond the visible spectrum.

  7. College Students' Time Management: Correlations with Academic Performance and Stress.

    Science.gov (United States)

    Macan, Therese Hoff; And Others

    1990-01-01

    The relationships between time management of college students and self-reported academic performance and various affective measures of stress were explored for 123 undergraduates. The study indicates that self-reported time management is multidimensional and that there are important relationships among time management, performance, and stress.…

  8. Cross strip microchannel plate imaging photon counters with high time resolution

    Energy Technology Data Exchange (ETDEWEB)

    Stonehill, Laura C [Los Alamos National Laboratory; Shirey, Robert [Los Alamos National Laboratory; Rabin, Michael W [Los Alamos National Laboratory; Thompson, David C [Los Alamos National Laboratory; Siegmund, Oswald H W [U.C. BERKELEY; Vallerga, John V [U.C. BERKELEY; Tremsin, Anton S [U.C. BERKELEY

    2010-01-01

    We have implemented cross strip readout microchannel plate detectors in 18 mm active area format including open face (UV/particle) and sealed tube (optical) configurations. These have been tested with a field programmable gate array based parallel channel electronics for event encoding which can process high input event rates (> 5 MHz) with high spatial resolution. Using small pore MCPs (6 {micro}m) operated in a pair, we achieve gains of >5 x 10{sup 5} which is sufficient to provide spatial resolution of <35 {micro}m FHWM, with self triggered event timing accuracy of {approx}2 ns for sealed tube optical sensors. A peak quantum efficiency of {approx}19% at 500 nm has been achieved with SuperGenII photocathodes that have response over the 400 nm to 900 nm range. Local area counting rates of up to >200 events/mcp pore sec{sup -1} have been attained, along with image linearity and stability to better than 50 {micro}m.

  9. The Assessment of Grid Resolution for Real-time Flood Warning in Urban area

    Science.gov (United States)

    Hsu, M. H.; Huang, C. J.; Teng, W. H.; Huang, C. Y.

    2016-12-01

    According to the unique natural environment, Taiwan confronts a severe flood damage problem in typhoon seasons. Recently, due to global climate change and extreme weather, the prediction and prevention of flood damage becomes one of the most important research issues. The highly development area and densely concentrated population result in severe damage during flood occurs. Flood management and response plan become more important in metropolitan area. For the past two decades, the hydrological monitory and rainfall intense prediction techniques have a great progress in its accuracy. QPESUMS (Quantitative Precipitation Estimation and Segregation Using Multiple Sensors) developed by the Central Weather Bureau was applied to observe real-time Radar rainfall and its spatial distribution. DTM (Digital Terrain Model) and 2D inundation model which considers the blockage effect of buildings were applied to simulate the water depth in metropolitan area. In this study, Kaohsiung city is selected as the study area and typhoon Fanapi which makes tremendous flood damage in Southern Taiwan in 2010 is adopted as the study case. The main purpose of this study is to find the proper grid resolution of flood forecasting computations in Kaohsiung city from the evaluations of the efficiency and accuracy of three different resolutions.

  10. Timing performance of ZnO: Ga nanopowder composite scintillators

    Czech Academy of Sciences Publication Activity Database

    Turtos, R.M.; Gundacker, S.; Lucchini, M.T.; Procházková, L.; Čuba, V.; Burešová, H.; Mrázek, Jan; Nikl, Martin; Lecoq, P.; Auffray, E.

    2016-01-01

    Roč. 10, č. 11 (2016), s. 843-847 ISSN 1862-6254 R&D Projects: GA ČR GA13-09876S EU Projects: European Commission(XE) 690599 - ASCIMAT Grant - others:COST(XE) TD1401 Institutional support: RVO:67985882 ; RVO:68378271 Keywords : nanocrystals * coincidence time resolution * scintillators ZnO:Ga Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering; BM - Solid Matter Physics ; Magnetism (FZU-D) Impact factor: 3.032, year: 2016

  11. LIS/OTD 2.5 Degree Low Resolution Annual Climatology Time Series (LRACTS) V2.3.2015

    Data.gov (United States)

    National Aeronautics and Space Administration — The LIS/OTD 2.5 Degree Low Resolution Annual Climatology Time Series (LRACTS) consists of gridded climatologies of total lightning flash rates seen by the spaceborne...

  12. LIS/OTD 2.5 Degree Low Resolution Monthly Climatology Time Series (LRMTS) V2.3.2015

    Data.gov (United States)

    National Aeronautics and Space Administration — The LIS/OTD 2.5 Degree Low Resolution Monthly Climatology Time Series (LRMTS) contains a variety of gridded climatologies of total lightning flash rates obtained...

  13. LIS/OTD 2.5 Degree Low Resolution Time Series (LRTS) V2.3.2015

    Data.gov (United States)

    National Aeronautics and Space Administration — The LIS/OTD 2.5 Degree Low Resolution Time Series (LRTS) contains a variety of gridded climatologies of total lightning flash rates obtained from two lightning...

  14. Increasing the time resolution of a pulse width modulator in a class D power amplifier by using delay lines

    Science.gov (United States)

    Weber, M.; Vennemann, T.; Mathis, W.

    2014-11-01

    In this paper, we present a method to increase the time resolution of a pulse width modulator by using delay lines. The modulator is part of an open loop class D power amplifier, which uses the ZePoC algorithm to code the audio signal which is amplified in the class D power stage. If the time resolution of the pulse width modulator is high enough, ZePoC could also be used to build an high accuracy AC power standard, because of its open loop property. With the presented method the time resolution theoretically could be increased by a factor of 16, which means here the time resolution will be enhanced from 5 ns to 312.5 ps.

  15. Clinical evaluation of reducing acquisition time on single-photon emission computed tomography image quality using proprietary resolution recovery software.

    Science.gov (United States)

    Aldridge, Matthew D; Waddington, Wendy W; Dickson, John C; Prakash, Vineet; Ell, Peter J; Bomanji, Jamshed B

    2013-11-01

    A three-dimensional model-based resolution recovery (RR) reconstruction algorithm that compensates for collimator-detector response, resulting in an improvement in reconstructed spatial resolution and signal-to-noise ratio of single-photon emission computed tomography (SPECT) images, was tested. The software is said to retain image quality even with reduced acquisition time. Clinically, any improvement in patient throughput without loss of quality is to be welcomed. Furthermore, future restrictions in radiotracer supplies may add value to this type of data analysis. The aims of this study were to assess improvement in image quality using the software and to evaluate the potential of performing reduced time acquisitions for bone and parathyroid SPECT applications. Data acquisition was performed using the local standard SPECT/CT protocols for 99mTc-hydroxymethylene diphosphonate bone and 99mTc-methoxyisobutylisonitrile parathyroid SPECT imaging. The principal modification applied was the acquisition of an eight-frame gated data set acquired using an ECG simulator with a fixed signal as the trigger. This had the effect of partitioning the data such that the effect of reduced time acquisitions could be assessed without conferring additional scanning time on the patient. The set of summed data sets was then independently reconstructed using the RR software to permit a blinded assessment of the effect of acquired counts upon reconstructed image quality as adjudged by three experienced observers. Data sets reconstructed with the RR software were compared with the local standard processing protocols; filtered back-projection and ordered-subset expectation-maximization. Thirty SPECT studies were assessed (20 bone and 10 parathyroid). The images reconstructed with the RR algorithm showed improved image quality for both full-time and half-time acquisitions over local current processing protocols (Pquality compared with local processing protocols and has been introduced into

  16. REAL-TIME high-resolution urban surface water flood mapping to support flood emergency management

    Science.gov (United States)

    Guan, M.; Yu, D.; Wilby, R.

    2016-12-01

    Strong evidence has shown that urban flood risks will substantially increase because of urbanisation, economic growth, and more frequent weather extremes. To effectively manage these risks require not only traditional grey engineering solutions, but also a green management solution. Surface water flood risk maps based on return period are useful for planning purposes, but are limited for application in flood emergencies, because of the spatiotemporal heterogeneity of rainfall and complex urban topography. Therefore, a REAL-TIME urban surface water mapping system is highly beneficial to increasing urban resilience to surface water flooding. This study integrated numerical weather forecast and high-resolution urban surface water modelling into a real-time multi-level surface water mapping system for Leicester City in the UK. For rainfall forecast, the 1km composite rain radar from the Met Office was used, and we used the advanced rainfall-runoff model - FloodMap to predict urban surface water at both city-level (10m-20m) and street-level (2m-5m). The system is capable of projecting 3-hour urban surface water flood, driven by rainfall derived from UK Met Office radar. Moreover, this system includes real-time accessibility mapping to assist the decision-making of emergency responders. This will allow accessibility (e.g. time to travel) from individual emergency service stations (e.g. Fire & Rescue; Ambulance) to vulnerable places to be evaluated. The mapping results will support contingency planning by emergency responders ahead of potential flood events.

  17. The effect of extrinsic motivation on cycle time trial performance

    NARCIS (Netherlands)

    Hulleman, M.; de Koning, J.J.; Hettinga, F.J.; Foster, C.

    2007-01-01

    PURPOSE: Athletes occasionally follow pacing patterns that seem unreasonably aggressive compared with those of prerace performances, potentially because of the motivation provided by competition. This study evaluated the effect of extrinsic motivation on cyclists' time trial performance. METHODS:

  18. Real-Time Application Performance Steering and Adaptive Control

    National Research Council Canada - National Science Library

    Reed, Daniel

    2002-01-01

    .... The objective of the Real-time Application Performance Steering and Adaptive Control project is to replace ad hoc, post-mortem performance optimization with an extensible, portable, and distributed...

  19. Generation of future high-resolution rainfall time series with a disaggregation model

    Science.gov (United States)

    Müller, Hannes; Haberlandt, Uwe

    2017-04-01

    High-resolution rainfall data are needed in many fields of hydrology and water resources management. For analyzes of future rainfall condition climate scenarios exist with hourly values of rainfall. However, the direct usage of these data is associated with uncertainties which can be indicated by comparisons of observations and C20 control runs. An alternative is the derivation of changes of rainfall behavior over the time from climate simulations. Conclusions about future rainfall conditions can be drawn by adding these changes to observed time series. A multiplicative cascade model is used in this investigation for the disaggregation of daily rainfall amounts to hourly values. Model parameters can be estimated by REMO rainfall time series (UBA-, BfG- and ENS-realization), based on ECHAM5. Parameter estimation is carried out for C20 period as well as near term and long term future (2021-2050 and 2071-2100). Change factors for both future periods are derived by parameter comparisons and added to the parameters estimated from observed time series. This enables the generation of hourly rainfall time series from observed daily values with respect to future changes. The investigation is carried out for rain gauges in Lower Saxony. Generated Time series are analyzed regarding statistical characteristics, e.g. extreme values, event-based (wet spell duration and amounts, dry spell duration, …) and continuum characteristics (average intensity, fraction of dry intervals,…). The generation of the time series is validated by comparing the changes in the statistical characteristics from the REMO data and from the disaggregated data.

  20. Performance Evaluation of Super-Resolution Reconstruction Methods on Real-World Data

    Directory of Open Access Journals (Sweden)

    L. J. van Vliet

    2007-01-01

    Full Text Available The performance of a super-resolution (SR reconstruction method on real-world data is not easy to measure, especially as a ground-truth (GT is often not available. In this paper, a quantitative performance measure is used, based on triangle orientation discrimination (TOD. The TOD measure, simulating a real-observer task, is capable of determining the performance of a specific SR reconstruction method under varying conditions of the input data. It is shown that the performance of an SR reconstruction method on real-world data can be predicted accurately by measuring its performance on simulated data. This prediction of the performance on real-world data enables the optimization of the complete chain of a vision system; from camera setup and SR reconstruction up to image detection/recognition/identification. Furthermore, different SR reconstruction methods are compared to show that the TOD method is a useful tool to select a specific SR reconstruction method according to the imaging conditions (camera's fill-factor, optical point-spread-function (PSF, signal-to-noise ratio (SNR.

  1. High-efficient method for spectrometric data real time processing with increased resolution of a measuring channel

    International Nuclear Information System (INIS)

    Ashkinaze, S.I.; Voronov, V.A.; Nechaev, Yu.I.

    1988-01-01

    Solution of reduction problem as a mean to increase spectrometric tract resolution when it is realized using the digit-by-digit modified method and special strategy, significantly reducing the time of processing, is considered. The results presented confirm that the complex measurement tract plus microcomputer is equivalent to the use of the tract with a higher resolution, and the use of the digit-by-digit modified method permits to process spectrometric information in real time scale

  2. Direct Push Optical Screening Tool for High Resolution, Real-Time Mapping of Chlorinated Solvent DNAPL Architecture

    Science.gov (United States)

    2016-07-01

    sites impacted by petroleum hydrocarbon fuels, creosotes , and MGP tars. The rapid, high-resolution, real-time nature of LIF technologies described...Green Optical Screening Tool (TarGOST®) are popular tools for real-time, high-resolution mapping of petroleum hydrocarbons, creosotes , and coal tar...solvent DNAPL at many sites will have more complex architectures and be present at lower saturations and in thinner layers than MGP tar, creosote , and

  3. Novel Super-Resolution Approach to Time-Resolved Volumetric 4-Dimensional Magnetic Resonance Imaging With High Spatiotemporal Resolution for Multi-Breathing Cycle Motion Assessment.

    Science.gov (United States)

    Li, Guang; Wei, Jie; Kadbi, Mo; Moody, Jason; Sun, August; Zhang, Shirong; Markova, Svetlana; Zakian, Kristen; Hunt, Margie; Deasy, Joseph O

    2017-06-01

    To develop and evaluate a super-resolution approach to reconstruct time-resolved 4-dimensional magnetic resonance imaging (TR-4DMRI) with a high spatiotemporal resolution for multi-breathing cycle motion assessment. A super-resolution approach was developed to combine fast 3-dimensional (3D) cine MRI with low resolution during free breathing (FB) and high-resolution 3D static MRI during breath hold (BH) using deformable image registration. A T1-weighted, turbo field echo sequence, coronal 3D cine acquisition, partial Fourier approximation, and SENSitivity Encoding parallel acceleration were used. The same MRI pulse sequence, field of view, and acceleration techniques were applied in both FB and BH acquisitions; the intensity-based Demons deformable image registration method was used. Under an institutional review board-approved protocol, 7 volunteers were studied with 3D cine FB scan (voxel size: 5 × 5 × 5 mm 3 ) at 2 Hz for 40 seconds and a 3D static BH scan (2 × 2 × 2 mm 3 ). To examine the image fidelity of 3D cine and super-resolution TR-4DMRI, a mobile gel phantom with multi-internal targets was scanned at 3 speeds and compared with the 3D static image. Image similarity among 3D cine, 4DMRI, and 3D static was evaluated visually using difference image and quantitatively using voxel intensity correlation and Dice index (phantom only). Multi-breathing-cycle waveforms were extracted and compared in both phantom and volunteer images using the 3D cine as the references. Mild imaging artifacts were found in the 3D cine and TR-4DMRI of the mobile gel phantom with a Dice index of >0.95. Among 7 volunteers, the super-resolution TR-4DMRI yielded high voxel-intensity correlation (0.92 ± 0.05) and low voxel-intensity difference (Super-resolution TR-4DMRI has been reconstructed with adequate temporal (2 Hz) and spatial (2 × 2 × 2 mm 3 ) resolutions. Further TR-4DMRI characterization and improvement are necessary before clinical applications. Multi

  4. Continuous real-time digital data acquisition with high-resolution visible and infrared CCD cameras

    Science.gov (United States)

    Stufflebeam, Joseph L.; Waldie, Arthur H.; Qualtrough, John A.; Soules, David B.; Ambrose, Joseph G.; Reed, Michelle F.

    1993-08-01

    A high speed digital interface has been developed to accept real time digital pixel data from high resolution CCD cameras. The interface is currently in use with both a 640 X 486 12-bit digital infrared camera operating in non-interlaced mode at 30 frames per second, and a 756 X 484 8-bit digital visible camera operating in interlaced mode at 60 fields per second. Using programmable logic, the interface is reconfigurable to accept digital data from a variety of sensors at data rates of up to 18 megabytes per second. The buffered digital data is recorded on a hard disk array consisting of up to nine individual drives, with a present capacity exceeding 5.9 gigabytes. Continuous recording is achieved by implementing a loop function on the disk array.

  5. Monitoring agricultural expansion in Burkina Faso over 14 years with 30 m resolution time series

    DEFF Research Database (Denmark)

    Knauer, Kim; Gessner, Ursula; Fensholt, Rasmus

    2017-01-01

    and 3000 MODIS scenes were processed with this automated framework. The generated ESTARFM NDVI time series enabled extraction of per-pixel phenological features that all together served as input for the delineation of agricultural areas via random forest classification at 30 m spatial resolution for entire......Burkina Faso ranges amongst the fastest growing countries in the world with an annual population growth rate of more than three percent. This trend has consequences for food security since agricultural productivity is still on a comparatively low level in Burkina Faso. In order to compensate...... for the low productivity, the agricultural areas are expanding quickly. The mapping and monitoring of this expansion is difficult, even on the basis of remote sensing imagery, since the extensive farming practices and frequent cloud coverage in the area make the delineation of cultivated land from other land...

  6. Auditory temporal resolution and integration - stages of analyzing time-varying sounds

    DEFF Research Database (Denmark)

    Pedersen, Benjamin

    2007-01-01

    . Specifically, the auditory tasks of the described experiments may be considered as falling into two categories: (1) Temporal integration when listeners have to judge the overall loudness of relatively long (compared to the temporal resolution of the auditory system) sounds fluctuating in level, and (2......) temporal pattern recognition where listeners have to identify properties of the actual patterns of level changes. Typically temporal processing is modeled by some sort of temporal summation or integration device. The results of the present experiments are to a large extent incompatible with this modeling...... scheme: Effects such as attention seem to play an important role in loudness integration, and further, it will be demonstrated that the auditory system can rely on temporal cues at a much finer level of detail than predicted be existing models (temporal details in the time-range of 60 ?s can...

  7. Performance improvement of the high resolution neutron diffractometer at CAEP with Geant4 simulation

    International Nuclear Information System (INIS)

    Zhang, J.; Xia, Y.; Zhang, Y.; Pang, B.; Sun, G.; Li, J.; Huang, C.; Wang, Y.; Pan, J.; Xie, C.

    2017-01-01

    The newly-built high resolution neutron diffractometer (HRND) at China Academy of Engineering Physics (CAEP) could not acquire high-quality diffraction patterns. In order to solve the problem, the present work introduces the Monte Carlo method based software called Geant4 which is rarely applied in the field of neutron diffraction. The geometrical structure of HRND has been structured by Geant4, thus simulation results can not only re-display the problems of HRND but help to solve such problems as well. According to the simulation results, some effective measures have been carried out to obtain higher instrument performance. It is found that the performance of HRND is improved eventually after new experimental diffraction patterns are acquired.

  8. Performance improvement of the high resolution neutron diffractometer at CAEP with Geant4 simulation

    Science.gov (United States)

    Zhang, J.; Xia, Y.; Zhang, Y.; Pang, B.; Sun, G.; Li, J.; Huang, C.; Wang, Y.; Pan, J.; Xie, C.

    2017-10-01

    The newly-built high resolution neutron diffractometer (HRND) at China Academy of Engineering Physics (CAEP) could not acquire high-quality diffraction patterns. In order to solve the problem, the present work introduces the Monte Carlo method based software called Geant4 which is rarely applied in the field of neutron diffraction. The geometrical structure of HRND has been structured by Geant4, thus simulation results can not only re-display the problems of HRND but help to solve such problems as well. According to the simulation results, some effective measures have been carried out to obtain higher instrument performance. It is found that the performance of HRND is improved eventually after new experimental diffraction patterns are acquired.

  9. Parotid gland shrinkage during IMRT predicts the time to Xerostomia resolution.

    Science.gov (United States)

    Sanguineti, Giuseppe; Ricchetti, Francesco; Wu, Binbin; McNutt, Todd; Fiorino, Claudio

    2015-01-17

    To assess the impact of mid-treatment parotid gland shrinkage on long term xerostomia during IMRT for oropharyngeal SCC. All patients treated with IMRT at a single Institution from November 2007 to June 2010 and undergoing weekly CT scans were selected. Parotid glands were contoured retrospectively on the mid treatment CT scan. For each parotid gland, the percent change relative to the planning volume was calculated and combined as weighted average. Patients were considered to be xerostomic if developed GR2+ dry mouth according to CTCAE v3.0. Predictors of the time to xerostomia resolution or downgrade to 1 were investigated at both uni- and multivariate analysis. 85 patients were selected. With a median follow up of 35.8 months (range: 2.4-62.6 months), the actuarial rate of xerostomia is 26.2% (SD: 5.3%) and 15.9% (SD: 5.3%) at 2 and 3 yrs, respectively. At multivariate analysis, mid-treatment shrink along with weighted average mean parotid dose at planning and body mass index are independent predictors of the time to xerostomia resolution. Patients were pooled in 4 groups based on median values of both mid-treatment shrink (cut-off: 19.6%) and mean WA parotid pl-D (cut-off: 35.7 Gy). Patients with a higher than median parotid dose at planning and who showed poor shrinkage at mid treatment are the ones with the outcome significantly worse (3-yr rate of xerostomia ≈ 50%) than the other three subgroups (3-yr rate of xerostomia ≈ 10%). For a given planned dose, patients whose parotids significantly shrink during IMRT are less likely to be long-term supplemental fluids dependent.

  10. High-Resolution Gravity and Time-Varying Gravity Field Recovery using GRACE and CHAMP

    Science.gov (United States)

    Shum, C. K.

    2002-01-01

    This progress report summarizes the research work conducted under NASA's Solid Earth and Natural Hazards Program 1998 (SENH98) entitled High Resolution Gravity and Time Varying Gravity Field Recovery Using GRACE (Gravity Recovery and Climate Experiment) and CHAMP (Challenging Mini-satellite Package for Geophysical Research and Applications), which included a no-cost extension time period. The investigation has conducted pilot studies to use the simulated GRACE and CHAMP data and other in situ and space geodetic observable, satellite altimeter data, and ocean mass variation data to study the dynamic processes of the Earth which affect climate change. Results from this investigation include: (1) a new method to use the energy approach for expressing gravity mission data as in situ measurements with the possibility to enhance the spatial resolution of the gravity signal; (2) the method was tested using CHAMP and validated with the development of a mean gravity field model using CHAMP data, (3) elaborate simulation to quantify errors of tides and atmosphere and to recover hydrological and oceanic signals using GRACE, results show that there are significant aliasing effect and errors being amplified in the GRACE resonant geopotential and it is not trivial to remove these errors, and (4) quantification of oceanic and ice sheet mass changes in a geophysical constraint study to assess their contributions to global sea level change, while the results improved significant over the use of previous studies using only the SLR (Satellite Laser Ranging)-determined zonal gravity change data, the constraint could be further improved with additional information on mantle rheology, PGR (Post-Glacial Rebound) and ice loading history. A list of relevant presentations and publications is attached, along with a summary of the SENH investigation generated in 2000.

  11. Ensemble Time in GNSS - Performance Requirements and Algorithm Tests

    National Research Council Canada - National Science Library

    Suess, Mattgias; Moudrak, Alexandre; Frolova, E

    2007-01-01

    Any Global Navigation Satellite System (GNSS) relies on a highly stable and reliable System Time that has to meet high-performance requirements to enable GNSS services suitable for navigation and timing communities...

  12. Enhanced Processing of 1-km Spatial Resolution fAPAR Time Series for Sugarcane Yield Forecasting and Monitoring

    Directory of Open Access Journals (Sweden)

    Bettina Baruth

    2013-03-01

    Full Text Available A processing of remotely-sensed Fraction of Absorbed Photosynthetically Active Radiation (fAPAR time series at 1-km spatial resolution is established to estimate sugarcane yield over the state of São Paulo, Brazil. It includes selecting adequate time series according to the signal spatial purity, using thermal time instead of calendar time and smoothing temporally the irregularly sampled observations. A systematic construction of various metrics and their capacity to predict yield is explored to identify the best performance, and see how timely the yield forecast can be made. The resulting dataset not only reveals a strong spatio-temporal structure, but is also capable of detecting both absolute changes in biomass accumulation and changes in its inter-annual variability. Sugarcane yield can thus be estimated with a RMSE of 1.5 t/ha (or 2% without taking into account the strong linear trend in yield increase witnessed in the past decade. Including the trend reduces the error to 0.6 t/ha, correctly predicting whether the yield in a given year is above or below the trend in 90% of cases. The methodological framework presented here could be applied beyond the specific case of sugarcane in São Paulo, namely to other crops in other agro-ecological landscapes, to enhance current systems for monitoring agriculture or forecasting yield using remote sensing.

  13. Polarized high-brilliance and high-resolution soft x-ray source at ELETTRA: The performance of beamline BACH

    International Nuclear Information System (INIS)

    Zangrando, M.; Zacchigna, M.; Finazzi, M.; Cocco, D.; Rochow, R.; Parmigiani, F.

    2004-01-01

    BACH, a soft x-ray beamline for polarization-dependent experiments at the Italian synchrotron radiation facility ELETTRA, was recently completed and characterized. Its performance, in terms of energy resolution, flux and polarization, is presented. Based on two APPLE II undulators, BACH covers the energy range between 35 and 1600 eV with the control of the light polarization. The monochromator is equipped with four gratings and allows one to work either in a high resolution or in a high flux mode. After the monochromator, the beamline is split into two branches with different refocusing properties. One is optimized to exploit the performance of the soft x-ray spectrometer (ComIXS) available at the beamline. Resolving powers between 12000 at 90 eV photon energy and 6600 near 867 eV were achieved using the high-resolution gratings and the smallest available slit width (10 μm). For the high-brilliance grating, which works between 290 and 1600 eV, resolving powers between 7000 at 400 eV and 2200 at 867 eV were obtained. The flux in the experimental chamber, measured with the high-resolution gratings for linearly polarized light at the best achievable resolution, ranges between 4x10 11 photons/s at 125 eV and 2x10 10 photons/s between 900 and 1250 eV. In circularly polarized mode the flux is two times larger for energies up to 380 eV. A gain of nearly one order of magnitude is obtained for the high-brilliance grating, in accordance with theoretical predictions. Flux beyond 1.3x10 11 photons/s was measured up to 1300 eV, and thus over nearly the complete energy range covered by this high-brilliance grating, with a maximum of 1.6x10 11 photons/s between 800 and 1100 eV. First results from polarization measurements confirm a polarization above 99.7% for both linearly and circularly polarized modes at low energies. Circular dichroism experiments indicate a circular polarization beyond 90% at the Fe L 2 /L 3 edge near 720 eV

  14. High-resolution spectroscopy and time-resolved study of electroluminescence of Er-1 center in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Kudryavtsev, K.E., E-mail: konstantin@ipm.sci-nnov.r [Institute for Physics of Microstructures, GSP-105, 603950 Nizhniy Novgorod (Russian Federation); Shmagin, V.B.; Shengurov, D.V.; Krasilnik, Z.F. [Institute for Physics of Microstructures, GSP-105, 603950 Nizhniy Novgorod (Russian Federation)

    2009-12-15

    High-resolution and time-resolved measurements on the electroluminescence from Er-doped silicon diode structures with Er-1 center, grown with sublimation molecular beam epitaxy, have been performed within the temperature interval 30-120 K. We find emission lines with full width down to 0.2 cm{sup -1} (25 mueV) at 30 K, the narrowest lines ever observed in Si:Er electroluminescence spectra, and excitation cross-section of 4x1{sup -15} cm{sup 2}. Auger-deexcitation of Er{sup 3+} ions with the activation energy of 16 meV was found to be the only deexcitation process in these structures and no 'back-transfer' deexcitation was observed. Due to ultra narrow emission lines and a high excitation cross-section such diode structures are promising for realization of an electrically pumped silicon-based laser.

  15. A Numerical Method to Generate High Temporal Resolution Precipitation Time Series by Combining Weather Radar Measurements with a Nowcast Model

    DEFF Research Database (Denmark)

    Nielsen, Jesper Ellerbæk; Thorndahl, Søren Liedtke; Rasmussen, Michael R.

    2014-01-01

    for vector field estimation already known from short-term weather radar nowcasting. However, instead of forecasting the weather radar rainfall, the proposed interpolation method exploits the advection of the rainfall in the interpolation. The interpolated rainfall fields are validated by measurements......The topic of this paper is temporal interpolation of precipitation observed by weather radars. Precipitation measurements with high spatial and temporal resolution are, in general, desired for urban drainage applications. An advection-based interpolation method is developed which uses methods...... at ground level from laser disdrometers. The proposed interpolation method performs better when compared to traditional interpolation of weather radar rainfall where the radar observation is considered constant in time between measurements. It is demonstrated that the advection-based interpolation method...

  16. The performance of the new enhanced-resolution satellite passive microwave dataset applied for snow water equivalent estimation

    Science.gov (United States)

    Pan, J.; Durand, M. T.; Jiang, L.; Liu, D.

    2017-12-01

    The newly-processed NASA MEaSures Calibrated Enhanced-Resolution Brightness Temperature (CETB) reconstructed using antenna measurement response function (MRF) is considered to have significantly improved fine-resolution measurements with better georegistration for time-series observations and equivalent field of view (FOV) for frequencies with the same monomial spatial resolution. We are looking forward to its potential for the global snow observing purposes, and therefore aim to test its performance for characterizing snow properties, especially the snow water equivalent (SWE) in large areas. In this research, two candidate SWE algorithms will be tested in China for the years between 2005 to 2010 using the reprocessed TB from the Advanced Microwave Scanning Radiometer for EOS (AMSR-E), with the results to be evaluated using the daily snow depth measurements at over 700 national synoptic stations. One of the algorithms is the SWE retrieval algorithm used for the FengYun (FY) - 3 Microwave Radiation Imager. This algorithm uses the multi-channel TB to calculate SWE for three major snow regions in China, with the coefficients adapted for different land cover types. The second algorithm is the newly-established Bayesian Algorithm for SWE Estimation with Passive Microwave measurements (BASE-PM). This algorithm uses the physically-based snow radiative transfer model to find the histogram of most-likely snow property that matches the multi-frequency TB from 10.65 to 90 GHz. It provides a rough estimation of snow depth and grain size at the same time and showed a 30 mm SWE RMS error using the ground radiometer measurements at Sodankyla. This study will be the first attempt to test it spatially for satellite. The use of this algorithm benefits from the high resolution and the spatial consistency between frequencies embedded in the new dataset. This research will answer three questions. First, to what extent can CETB increase the heterogeneity in the mapped SWE? Second, will

  17. Resolution of ray-finned fish phylogeny and timing of diversification.

    Science.gov (United States)

    Near, Thomas J; Eytan, Ron I; Dornburg, Alex; Kuhn, Kristen L; Moore, Jon A; Davis, Matthew P; Wainwright, Peter C; Friedman, Matt; Smith, W Leo

    2012-08-21

    Ray-finned fishes make up half of all living vertebrate species. Nearly all ray-finned fishes are teleosts, which include most commercially important fish species, several model organisms for genomics and developmental biology, and the dominant component of marine and freshwater vertebrate faunas. Despite the economic and scientific importance of ray-finned fishes, the lack of a single comprehensive phylogeny with corresponding divergence-time estimates has limited our understanding of the evolution and diversification of this radiation. Our analyses, which use multiple nuclear gene sequences in conjunction with 36 fossil age constraints, result in a well-supported phylogeny of all major ray-finned fish lineages and molecular age estimates that are generally consistent with the fossil record. This phylogeny informs three long-standing problems: specifically identifying elopomorphs (eels and tarpons) as the sister lineage of all other teleosts, providing a unique hypothesis on the radiation of early euteleosts, and offering a promising strategy for resolution of the "bush at the top of the tree" that includes percomorphs and other spiny-finned teleosts. Contrasting our divergence time estimates with studies using a single nuclear gene or whole mitochondrial genomes, we find that the former underestimates ages of the oldest ray-finned fish divergences, but the latter dramatically overestimates ages for derived teleost lineages. Our time-calibrated phylogeny reveals that much of the diversification leading to extant groups of teleosts occurred between the late Mesozoic and early Cenozoic, identifying this period as the "Second Age of Fishes."

  18. Very-High-Resolution Time-Lapse Photography for Plant and Ecosystems Research

    Directory of Open Access Journals (Sweden)

    Mary H. Nichols

    2013-09-01

    Full Text Available Premise of the study: Traditional photography is a compromise between image detail and area covered. We report a new method for creating time-lapse sequences of very-high-resolution photographs to produce zoomable images that facilitate observation across a range of spatial and temporal scales. Methods and Results: A robotic camera mount and software were used to capture images of the growth and movement in Brassica rapa every 15 s in the laboratory. The resultant time-lapse sequence (http://timemachine.gigapan.org/wiki/Plant_Growth captures growth detail such as circumnutation. A modified, solar-powered system was deployed at a remote field site in southern Arizona. Images were collected every 2 h over a 3-mo period to capture the response of vegetation to monsoon season rainfall (http://timemachine.gigapan.org/wiki/Arizona_Grasslands. Conclusions: A technique for observing time sequences of both individual plant and ecosystem response at a range of spatial scales is available for use in the laboratory and in the field.

  19. Electric field measurements in a dielectric barrier nanosecond pulse discharge with sub-nanosecond time resolution

    International Nuclear Information System (INIS)

    Goldberg, Benjamin M; Shkurenkov, Ivan; Adamovich, Igor V; Lempert, Walter R; O’Byrne, Sean

    2015-01-01

    The paper presents the results of time-resolved electric field measurements in a nanosecond discharge between two plane electrodes covered by dielectric plates, using picosecond four-wave mixing diagnostics. For absolute calibration, the IR signal was measured in hydrogen at a pressure of 440 Torr, for electrostatic electric field ranging from 0 to 8 kV cm −1 . The calibration curve (i.e. the square root of IR signal intensity versus electric field) was shown to be linear. By measuring the intensities of the pump, Stokes, and IR signal beam for each laser shot during the time sweep across the high-voltage pulse, temporal evolution of the electric field in the nanosecond pulse discharge was determined with sub-nanosecond time resolution. The results are compared to kinetic modeling predictions, showing good agreement, including non-zero electric field offset before the main high voltage pulse, breakdown moment, and reduction of electric field in the plasma after breakdown. The difference between the experimental results and model predictions is likely due to non-1D structure of the discharge. Comparison with the kinetic modeling predictions shows that electric field in the nanosecond pulse discharge is controlled primarily by electron impact excitation and charge accumulation on the dielectric surfaces. (paper)

  20. Faster-Than-Real-Time Simulation of Lithium Ion Batteries with Full Spatial and Temporal Resolution

    Directory of Open Access Journals (Sweden)

    Sandip Mazumder

    2013-01-01

    Full Text Available A one-dimensional coupled electrochemical-thermal model of a lithium ion battery with full temporal and normal-to-electrode spatial resolution is presented. Only a single pair of electrodes is considered in the model. It is shown that simulation of a lithium ion battery with the inclusion of detailed transport phenomena and electrochemistry is possible with faster-than-real-time compute times. The governing conservation equations of mass, charge, and energy are discretized using the finite volume method and solved using an iterative procedure. The model is first successfully validated against experimental data for both charge and discharge processes in a LixC6-LiyMn2O4 battery. Finally, it is demonstrated for an arbitrary rapidly changing transient load typical of a hybrid electric vehicle drive cycle. The model is able to predict the cell voltage of a 15-minute drive cycle in less than 12 seconds of compute time on a laptop with a 2.33 GHz Intel Pentium 4 processor.

  1. The time-of-flight TOFW detector of the HARP experiment: construction and performance

    International Nuclear Information System (INIS)

    Baldo-Ceolin, M.; Barichello, G.; Bobisut, F.; Bonesini, M.; De Min, A.; Ferri, A.F.; Gibin, D.; Guglielmi, A.; Laveder, M.; Menegolli, A.; Mezzetto, M.; Paganoni, M.; Paleari, F.; Pepato, A.; Tonazzo, A.; Vascon, M.

    2004-01-01

    The construction and performance of a large area scintillator-based time-of-flight detector for the HARP experiment at CERN are reported. An intrinsic counter time resolution of ∼160 ps was achieved. The precision on the time calibration and monitoring of the detector was maintained at better than 100 ps by using dedicated cosmic rays runs, a fast laser-based system and calibrations with beam particles. The detector was operated on the T9 PS beamline during 2001 and 2002. A time-of-flight resolution of ∼200 ps was obtained, providing π/p discrimination at more than 3σ up to 4.0 GeV/c momentum

  2. Time-of-flight resolution of scintillating counters with Burle 85001 microchannel plate photomultipliers in comparison with Hamamatsu R2083

    Energy Technology Data Exchange (ETDEWEB)

    Baturin, V. [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Burkert, V. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Kim, W. [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of)]. E-mail: wooyoung@jlab.org; Majewsky, S. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Park, K. [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Popov, V. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Smith, E.S. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Son, D. [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Stepanyan, S.S. [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Zorn, C. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)

    2006-06-15

    Improvements in the time resolution of the CEBAF Large Acceptance Spectrometer (CLAS) below {approx}50ps will be required for experiments using the planned upgraded accelerator facility at Jefferson Lab. The improved time resolution will allow particle identification using time-of-flight techniques to be used effectively up to the proposed operating energy of 12GeV. The challenge of achieving this time resolution over a relatively large area is compounded because the photomultipliers (PM) in the CLAS 'time-zero' scintillating counters must operate in very high magnetic fields. Therefore, we have studied the resolution of 'time-zero' prototypes with microchannel plate PMs 85001-501 from Burle. For reference and comparison, measurements were also made using the standard PMs R2083 from Hamamatsu using two timing methods. The cosmic ray method, which utilizes three identical scintillating counters (Bicron BC-408, 2x3x50cm{sup 3}) with PMs at the ends, yields {sigma}{sub R2083}=59.1+/-0.7ps. The location method of particles from a radiative source with known coordinates has been used to compare timing resolutions of R2083 and 85001-501. This method yields {sigma}{sub R2083}=59.5+/-0.7ps and it also provides an estimate of the number of primary photoelectrons. For the microchannel plate PM from Burle the method yields {sigma}{sub 85001}=130+/-4ps due to lower number of primary photoelectrons.

  3. Comparing range data across the slow-time dimension to correct motion measurement errors beyond the range resolution of a synthetic aperture radar

    Science.gov (United States)

    Doerry, Armin W.; Heard, Freddie E.; Cordaro, J. Thomas

    2010-08-17

    Motion measurement errors that extend beyond the range resolution of a synthetic aperture radar (SAR) can be corrected by effectively decreasing the range resolution of the SAR in order to permit measurement of the error. Range profiles can be compared across the slow-time dimension of the input data in order to estimate the error. Once the error has been determined, appropriate frequency and phase correction can be applied to the uncompressed input data, after which range and azimuth compression can be performed to produce a desired SAR image.

  4. EUV high resolution imager on-board solar orbiter: optical design and detector performances

    Science.gov (United States)

    Halain, J. P.; Mazzoli, A.; Rochus, P.; Renotte, E.; Stockman, Y.; Berghmans, D.; BenMoussa, A.; Auchère, F.

    2017-11-01

    The EUV high resolution imager (HRI) channel of the Extreme Ultraviolet Imager (EUI) on-board Solar Orbiter will observe the solar atmospheric layers at 17.4 nm wavelength with a 200 km resolution. The HRI channel is based on a compact two mirrors off-axis design. The spectral selection is obtained by a multilayer coating deposited on the mirrors and by redundant Aluminum filters rejecting the visible and infrared light. The detector is a 2k x 2k array back-thinned silicon CMOS-APS with 10 μm pixel pitch, sensitive in the EUV wavelength range. Due to the instrument compactness and the constraints on the optical design, the channel performance is very sensitive to the manufacturing, alignments and settling errors. A trade-off between two optical layouts was therefore performed to select the final optical design and to improve the mirror mounts. The effect of diffraction by the filter mesh support and by the mirror diffusion has been included in the overall error budget. Manufacturing of mirror and mounts has started and will result in thermo-mechanical validation on the EUI instrument structural and thermal model (STM). Because of the limited channel entrance aperture and consequently the low input flux, the channel performance also relies on the detector EUV sensitivity, readout noise and dynamic range. Based on the characterization of a CMOS-APS back-side detector prototype, showing promising results, the EUI detector has been specified and is under development. These detectors will undergo a qualification program before being tested and integrated on the EUI instrument.

  5. EEG can track the time course of successful reference resolution in small visual worlds

    Directory of Open Access Journals (Sweden)

    Christian eBrodbeck

    2015-11-01

    Full Text Available Previous research has shown that language comprehenders resolve reference quickly and incrementally, but not much is known about the neural processes and representations that are involved. Studies of visual short-term memory suggest that access to the representation of an item from a previously seen display is associated with a negative evoked potential at posterior electrodes contralateral to the spatial location of that item in the display. In this paper we demonstrate that resolving the reference of a noun phrase in a recently seen visual display is associated with an event-related potential that is analogous to this effect. Our design was adapted from the visual world paradigm: in each trial, participants saw a display containing 3 simple objects, followed by a question about the objects, such as Was the pink fish next to a boat?, presented word by word. Questions differed in whether the color adjective allowed the reader to identify the referent of the noun phrase or not (i.e., whether one or more objects of the named color were present. Consistent with our hypothesis, we observed that reference resolution by the adjective was associated with a negative evoked potential at posterior electrodes contralateral to spatial location of the referent, starting approximately 333 ms after the onset of the adjective. The fact that the laterality of the effect depended upon the location of the referent within the display suggests that reference resolution in visual domains involves, at some level, a modality-specific representation. In addition, the effect gives us an estimate of the time course of processing from perception of the written word to the point at which its meaning is brought into correspondence with the referential domain.

  6. New strategy to identify radicals in a time evolving EPR data set by multivariate curve resolution-alternating least squares

    Energy Technology Data Exchange (ETDEWEB)

    Fadel, Maya Abou [LASIR CNRS UMR 8516, Université Lille 1, Sciences et Technologies, 59655 Villeneuve d' Ascq Cedex (France); Juan, Anna de [Chemometrics Group, Section of Analytical Chemistry, Universitat de Barcelona, Diagonal 645, 08028 Barcelona (Spain); Vezin, Hervé [LASIR CNRS UMR 8516, Université Lille 1, Sciences et Technologies, 59655 Villeneuve d' Ascq Cedex (France); Duponchel, Ludovic, E-mail: ludovic.duponchel@univ-lille1.fr [LASIR CNRS UMR 8516, Université Lille 1, Sciences et Technologies, 59655 Villeneuve d' Ascq Cedex (France)

    2016-12-01

    Electron paramagnetic resonance (EPR) spectroscopy is a powerful technique that is able to characterize radicals formed in kinetic reactions. However, spectral characterization of individual chemical species is often limited or even unmanageable due to the severe kinetic and spectral overlap among species in kinetic processes. Therefore, we applied, for the first time, multivariate curve resolution-alternating least squares (MCR-ALS) method to EPR time evolving data sets to model and characterize the different constituents in a kinetic reaction. Here we demonstrate the advantage of multivariate analysis in the investigation of radicals formed along the kinetic process of hydroxycoumarin in alkaline medium. Multiset analysis of several EPR-monitored kinetic experiments performed in different conditions revealed the individual paramagnetic centres as well as their kinetic profiles. The results obtained by MCR-ALS method demonstrate its prominent potential in analysis of EPR time evolved spectra. - Highlights: • A new strategy to identify radicals in a time evolving EPR data set. • Extraction of pure EPR spectral signatures and corresponding kinetic profiles. • The proposed method does not require any prior knowledge of the chemical system. • A multiset analysis in order to decrease rotational ambiguity.

  7. Design and performance of AERHA, a high acceptance high resolution soft x-ray spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Chiuzbăian, Sorin G., E-mail: gheorghe.chiuzbaian@upmc.fr; Hague, Coryn F.; Brignolo, Stefania; Baumier, Cédric; Lüning, Jan [Sorbonne Universités, UPMC Univ Paris 06, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75005 Paris (France); CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75005 Paris (France); Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, B.P. 48, F-91192 Gif-sur-Yvette (France); Avila, Antoine; Delaunay, Renaud; Mariot, Jean-Michel [Sorbonne Universités, UPMC Univ Paris 06, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75005 Paris (France); CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75005 Paris (France); Jaouen, Nicolas; Polack, François; Thomasset, Muriel; Lagarde, Bruno; Nicolaou, Alessandro [Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, B.P. 48, F-91192 Gif-sur-Yvette (France); Sacchi, Maurizio [Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, B.P. 48, F-91192 Gif-sur-Yvette (France); Sorbonne Universités, UPMC Univ Paris 06, UMR 7588, Institut des NanoSciences de Paris, 4 place Jussieu, F-75252 Paris Cedex 05 (France); CNRS, UMR 7588, Institut des NanoSciences de Paris, 4 place Jussieu, F-75252 Paris Cedex 05 (France)

    2014-04-15

    A soft x-ray spectrometer based on the use of an elliptical focusing mirror and a plane varied line spacing grating is described. It achieves both high resolution and high overall efficiency while remaining relatively compact. The instrument is dedicated to resonant inelastic x-ray scattering studies. We set out how this optical arrangement was judged best able to guarantee performance for the 50 − 1000 eV range within achievable fabrication targets. The AERHA (adjustable energy resolution high acceptance) spectrometer operates with an effective angular acceptance between 100 and 250 μsr (energy dependent) and a resolving power well in excess of 5000 according to the Rayleigh criterion. The high angular acceptance is obtained by means of a collecting pre-mirror. Three scattering geometries are available to enable momentum dependent measurements with 135°, 90°, and 50° scattering angles. The instrument operates on the Synchrotron SOLEIL SEXTANTS beamline which serves as a high photon flux 2 × 200 μm{sup 2} focal spot source with full polarization control.

  8. High-resolution 3D simulations of NIF ignition targets performed on Sequoia with HYDRA

    Science.gov (United States)

    Marinak, M. M.; Clark, D. S.; Jones, O. S.; Kerbel, G. D.; Sepke, S.; Patel, M. V.; Koning, J. M.; Schroeder, C. R.

    2015-11-01

    Developments in the multiphysics ICF code HYDRA enable it to perform large-scale simulations on the Sequoia machine at LLNL. With an aggregate computing power of 20 Petaflops, Sequoia offers an unprecedented capability to resolve the physical processes in NIF ignition targets for a more complete, consistent treatment of the sources of asymmetry. We describe modifications to HYDRA that enable it to scale to over one million processes on Sequoia. These include new options for replicating parts of the mesh over a subset of the processes, to avoid strong scaling limits. We consider results from a 3D full ignition capsule-only simulation performed using over one billion zones run on 262,000 processors which resolves surface perturbations through modes l = 200. We also report progress towards a high-resolution 3D integrated hohlraum simulation performed using 262,000 processors which resolves surface perturbations on the ignition capsule through modes l = 70. These aim for the most complete calculations yet of the interactions and overall impact of the various sources of asymmetry for NIF ignition targets. This work was performed under the auspices of the Lawrence Livermore National Security, LLC, (LLNS) under Contract No. DE-AC52-07NA27344.

  9. Real-time performance evaluation of flooding & recursive time synchronization protocols over Arduino & XBee

    Science.gov (United States)

    Sattar, Danish

    Time synchronization plays an important role in distributed systems. Distributed wireless sensor networks (WSNs) often require accurate time synchronization for coordination and data reliability. The wireless sensor networks have three ma- jor goals: time synchronization, low bandwidth operation, and energy eciency. Dierent time synchronization algorithms aim to achieve these objectives using various methods. In this thesis, performance evaluation of two state-of-the-art time synchronization protocols is presented, namely; Flooding Time Synchronization Protocol and Recursive Time Synchronization Protocol. To achieve time synchronization in WSNs, these two protocols make use of dierent mechanisms: broadcast mechanism is used by Flooding Time Synchronization while peer-to-peer communication is used by Recursive Time Synchronization Protocol. As this is a performance evaluation, three performance parameters were set: the synchronization message count per cycle, the bandwidth and convergence time. Both have been veried using Arduino and XBee using various topologies including bus, grid, mesh, and tree. Each protocol performs dierently based on the topology.

  10. Statistically significant performance results of a mine detector and fusion algorithm from an x-band high-resolution SAR

    Science.gov (United States)

    Williams, Arnold C.; Pachowicz, Peter W.

    2004-09-01

    Current mine detection research indicates that no single sensor or single look from a sensor will detect mines/minefields in a real-time manner at a performance level suitable for a forward maneuver unit. Hence, the integrated development of detectors and fusion algorithms are of primary importance. A problem in this development process has been the evaluation of these algorithms with relatively small data sets, leading to anecdotal and frequently over trained results. These anecdotal results are often unreliable and conflicting among various sensors and algorithms. Consequently, the physical phenomena that ought to be exploited and the performance benefits of this exploitation are often ambiguous. The Army RDECOM CERDEC Night Vision Laboratory and Electron Sensors Directorate has collected large amounts of multisensor data such that statistically significant evaluations of detection and fusion algorithms can be obtained. Even with these large data sets care must be taken in algorithm design and data processing to achieve statistically significant performance results for combined detectors and fusion algorithms. This paper discusses statistically significant detection and combined multilook fusion results for the Ellipse Detector (ED) and the Piecewise Level Fusion Algorithm (PLFA). These statistically significant performance results are characterized by ROC curves that have been obtained through processing this multilook data for the high resolution SAR data of the Veridian X-Band radar. We discuss the implications of these results on mine detection and the importance of statistical significance, sample size, ground truth, and algorithm design in performance evaluation.

  11. Large Area and High Efficiency Photon Counting Imaging Detectors with High Time and Spatial Resolution for Night Time Sensing and Astronomy

    Science.gov (United States)

    Siegmund, O.; Vallerga, J.; Tremsin, A.; McPhate, J.; Frisch, H.; Elam, J.; Mane, A.; Wagner, R.; Varner, G.

    2012-09-01

    The development of large area photon counting, imaging, timing detectors with high performance has significance for applications in astronomy (such as our sensor on the SAAO SALT 10m telescope), night time remote reconnaissance, airborne/space situational awareness, and high-speed adaptive optics. Sealed tube configurations for optical/IR sensing also have applications in detection of Cherenkov light (RICH), biological single-molecule fluorescence lifetime imaging microscopy and neutron imaging applications. In open faced configurations these devices are important for UV and particle detection in space astrophysics, mass spectroscopy and many time-of flight applications. Currently available devices are limited to sizes of about 5 cm and use either conventional microchannel plates, or dynode multipliers for amplification, coupled coarse pad array readouts. Extension of these schemes to devices as large as 20 cm with high spatial resolution presents significant problems and potentially considerable cost. A collaboration (Large Area Picosecond Photon Detector) of the U. Chicago, Argonne National Laboratory, U.C. Berkeley, U. Hawaii and a number of other institutions has developed novel technologies to realize 20 cm format detectors in open face or sealed tube configurations. One critical component of this development is novel microchannel plates employing borosilicate micro-capillary arrays. The microchannel plates are based on a novel concept where the substrate is constructed from a borosilicate micro-capillary array that is made to function as a microchannel plate by deposition of resistive and secondary emissive layers using atomic layer deposition. The process is relatively inexpensive compared with conventional microchannel plates and allows very large microchannel plates to be produced with pore sizes as small as 10 microns. These provide many performance characteristics typical of conventional microchannel plates, but have been made in sizes up to 20 cm, have

  12. Homework and performance for time-constrained students

    OpenAIRE

    William Neilson

    2005-01-01

    Most studies of homework effectiveness relate time spent on homework to test performance, and find a nonmonotonic relationship. A theoretical model shows that this can occur even when additional homework helps all students because of the way in which variables are defined. However, some students are time-constrained, limiting the amount of homework they can complete. In the presence of time constraints, additional homework can increase the spread between the performance of the best and worst ...

  13. HIGH RESOLUTION PREDICTION OF GAS INJECTION PROCESS PERFORMANCE FOR HETEROGENEOUS RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Franklin M. Orr, Jr.

    2002-06-30

    This report outlines progress in the third quarter of the second year of the DOE project ''High Resolution Prediction of Gas Injection Process Performance for Heterogeneous Reservoirs''. High order finite difference schemes for one-dimensional, two-phase, multicomponent displacements are investigated. Numerical tests are run using a three component fluid description for a case when the interaction between phase behavior and flow is strong. Some currently used total variation diminishing (TVD) methods produce unstable results. A third order essentially non-oscillatory (ENO) method captures the effects of phase behavior for this test case. Possible modifications to ensure stability are discussed along with plans to incorporate higher order schemes into the 3DSL streamline simulator.

  14. HIGH RESOLUTION PREDICTION OF GAS INJECTION PROCESS PERFORMANCE FOR HETEROGENEOUS RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Franklin M. Orr, Jr.

    2001-12-31

    This report outlines progress in the first quarter of the second year of the DOE project ''High Resolution Prediction of Gas Injection Process Performance for Heterogeneous Reservoirs''. The application of the analytical theory for gas injection processes, including the effects of volume change on mixing, has up to now been limited to fully self-sharpening systems, systems where all solution segments that connect the key tie lines present in the displacement are shock fronts. In the following report, we describe the extension of the analytical theory to include systems with rarefactions (continuous composition and saturation variations) between key tie lines. With the completion of this analysis, a completely general procedure has been developed for finding solutions for problems in which a multicomponent gas displaces a multicomponent oil.

  15. Towards a High-resolution Time Scale for the Early Devonian

    Science.gov (United States)

    Dekkers, M. J.; da Silva, A. C.

    2017-12-01

    High-resolution time scales are crucial to understand Earth's history in detail. The construction of a robust geological time scale, however, inevitably becomes increasingly harder further back in time. Uncertainties associated with anchor radiometric ages increase in size, not speaking of the mere presence of suitable datable strata. However, durations of stages can be tightly constrained by making use of cyclic expressions in sediments, an approach that revolutionized the Cenozoic time scale. When precisely determined durations are stitched together, ultimately, a very precise time scale is the result. For the Mesozoic and Paleozoic an astronomical solution as a tuning target is not available but the dominant periods of eccentricity, obliquity and precession are reasonably well constrained for the entire Phanerozoic which enables their detection by means of spectral analysis. Eccentricity is time-invariant and is used as the prime building block. Here we focus on the Early Devonian, on its lowermost three stages: the Lochkovian, Pragian and Emsian. The uncertainties on the Devonian stage boundaries are currently in the order of several millions of years. The preservation of climatic cycles in diagenetically or even anchimetamorphically affected successions, however, is essential. The fit of spectral peak ratios with those calculated for orbital cycles, is classically used as a strong argument for a preserved climatic signal. Here we use primarily the low field magnetic susceptibility (MS) as proxy parameter, supported by gamma-ray spectrometry to test for consistency. Continuous Wavelet Transform, Evolutive Harmonic Analysis, Multitaper Method, and Average Spectral Misfit are used to reach an optimal astronomical interpretation. We report on classic Early Devonian sections from the Czech Republic: the Pozar-CS (Lochkovian and Pragian), Pod Barrandovem (Pragian and Lower Emsian), and Zlichov (Middle-Upper Emsian). Also a Middle-Upper Emsian section from the US

  16. Experimental and theoretical performance analysis for a CMOS-based high resolution image detector

    Science.gov (United States)

    Jain, Amit; Bednarek, Daniel R.; Rudin, Stephen

    2014-03-01

    Increasing complexity of endovascular interventional procedures requires superior x-ray imaging quality. Present stateof- the-art x-ray imaging detectors may not be adequate due to their inherent noise and resolution limitations. With recent developments, CMOS based detectors are presenting an option to fulfill the need for better image quality. For this work, a new CMOS detector has been analyzed experimentally and theoretically in terms of sensitivity, MTF and DQE. The detector (Dexela Model 1207, Perkin-Elmer Co., London, UK) features 14-bit image acquisition, a CsI phosphor, 75 μm pixels and an active area of 12 cm x 7 cm with over 30 fps frame rate. This detector has two modes of operations with two different full-well capacities: high and low sensitivity. The sensitivity and instrumentation noise equivalent exposure (INEE) were calculated for both modes. The detector modulation-transfer function (MTF), noise-power spectra (NPS) and detective quantum efficiency (DQE) were measured using an RQA5 spectrum. For the theoretical performance evaluation, a linear cascade model with an added aliasing stage was used. The detector showed excellent linearity in both modes. The sensitivity and the INEE of the detector were found to be 31.55 DN/μR and 0.55 μR in high sensitivity mode, while they were 9.87 DN/μR and 2.77 μR in low sensitivity mode. The theoretical and experimental values for the MTF and DQE showed close agreement with good DQE even at fluoroscopic exposure levels. In summary, the Dexela detector's imaging performance in terms of sensitivity, linear system metrics, and INEE demonstrates that it can overcome the noise and resolution limitations of present state-of-the-art x-ray detectors.

  17. Time-based prospective memory performance and time-monitoring in children with ADHD.

    Science.gov (United States)

    Zinke, Katharina; Altgassen, Mareike; Mackinlay, Rachael J; Rizzo, Patrizia; Drechsler, Renate; Kliegel, Matthias

    2010-01-01

    The current study investigated prospective memory (PM) performance in children with attention deficit/hyperactivity disorder (ADHD) and controls and aimed at exploring possible underlying factors of PM performance. Twenty-two children with ADHD and 39 age- and ability-matched typically developing children performed a computerized time-based PM task. As predicted, children with ADHD had fewer correct PM responses than controls. Neither differences in overall ongoing task performance nor, remarkably, differences in overall frequency and accuracy of time monitoring were found. Exploratory analyses suggest that individual differences in time monitoring in the final interval before target times may be related to PM performance in ADHD.

  18. Characterization of space-time rainfall patterns over Switzerland based on high-resolution radar images

    Science.gov (United States)

    Benoit, Lionel; Mariethoz, Gregoire; Vrac, Mathieu

    2017-04-01

    Rainfall is generated by diverse and complex processes that produce rain fields with a large variability of patterns. High-resolution measurements of rainfall, provided for instance by networks of terrestrial weather radars, allow observing the spatial variability of rainfall patterns and its temporal evolution. The characterization of these space-time rainfall patterns is important for both the understanding of rain generation processes and the study of environmental impacts of rainfall on hydrology, erosion or plants growth, among others. Here we propose to study rainfall patterns using image processing methods on high-resolution radar images (1km x 1km x 1min) over Switzerland. The time series of radar images is first segmented in rain events. Then, the spatial structure of each rain event is characterized by computing statistics over several geometrical indices extracted from radar images, by adapting to the context of mid-latitude rainfalls the indices proposed by Aghakouchak, Nasrollahi et al. (2011) and Zick and Matyas (2016) for tropical rainfall characterization. Finally, the dynamics of rainfall patterns is characterized by estimating rain advection through image correlation, and by quantifying the temporal morphing of spatial patterns in a Lagrangian reference frame, where radar images are re-projected to cancel out rain advection. Two years of data (2015 - 2016) are used to investigate the variability of rainfall patterns over Switzerland. Typical values of the indicators measuring rainfall patterns and their dynamics are extracted for different areas, namely the Jura Mountain, the Swiss Plateau and the Alps. These measures of rainfall variability could be subsequently used to parameterize local weather generators or to investigate the relationships between rainfall patterns and atmospheric synoptic conditions. References: Aghakouchak, A., N. Nasrollahi, J. Li, B. Imam and S. Sorooshian (2011). "Geometrical Characterization of Precipitation Patterns

  19. Real-time person detection in low-resolution thermal infrared imagery with MSER and CNNs

    Science.gov (United States)

    Herrmann, Christian; Müller, Thomas; Willersinn, Dieter; Beyerer, Jürgen

    2016-10-01

    In many camera-based systems, person detection and localization is an important step for safety and security applications such as search and rescue, reconnaissance, surveillance, or driver assistance. Long-wave infrared (LWIR) imagery promises to simplify this task because it is less affected by background clutter or illumination changes. In contrast to a lot of related work, we make no assumptions about any movement of persons or the camera, i.e. persons may stand still and the camera may move or any combination thereof. Furthermore, persons may appear arbitrarily in near or far distances to the camera leading to low-resolution persons in far distances. To address this task, we propose a two-stage system, including a proposal generation method and a classifier to verify, if the detected proposals really are persons. In contradiction to use all possible proposals as with sliding window approaches, we apply Maximally Stable Extremal Regions (MSER) and classify the detected proposals afterwards with a Convolutional Neural Network (CNN). The MSER algorithm acts as a hot spot detector when applied to LWIR imagery. Because the body temperature of persons is usually higher than the background, they appear as hot spots in the image. However, the MSER algorithm is unable to distinguish between different kinds of hot spots. Thus, all further LWIR sources such as windows, animals or vehicles will be detected, too. Still by applying MSER, the number of proposals is reduced significantly in comparison to a sliding window approach which allows employing the high discriminative capabilities of deep neural networks classifiers that were recently shown in several applications such as face recognition or image content classification. We suggest using a CNN as classifier for the detected hot spots and train it to discriminate between person hot spots and all further hot spots. We specifically design a CNN that is suitable for the low-resolution person hot spots that are common with

  20. Radio and X-ray observations of a multiple impulsive solar burst with high time resolution

    International Nuclear Information System (INIS)

    Kosugi, T.

    1981-01-01

    A well-developed multiple impulsive microwave burst occurred on February 17, 1979 simultaneously with a hard X-ray burst and a large group of type III bursts at metric wavelengths. The whole event is composed of serveral subgroups of elementary spike bursts. Detailed comparisons between these three classes of emissions with high time resolution of approx. equal to0.5 s reveal that individual type III bursts coincide in time with corresponding elementary X-ray and microwave spike bursts. It suggests that a non-thermal electron pulse generating a type III spike burst is produced simultaneously with those responsible for the corresponding hard X-ray and microwave spike bursts. The rise and decay characteristic time scales of the elementary spike burst are << 1 s, and approx. equal to1 s and approx. equal to3 s for type III, hard X-ray and microwave emissions respectively. Radio interferometric observations made at 17 GHz reveal that the spatial structure varies from one subgroup to others while it remains unchanged in a subgroup. Spectral evolution of the microwave burst seems to be closely related to the spatial evolution. The spatial evolution together with the spectral evolution suggests that the electron-accelerating region shifts to a different location after it stays at one location for several tens of seconds, duration of a subgroup of elementary spike bursts. We discuss several requirements for a model of the impulsive burst which come out from these observational results, and propose a migrating double-source model. (orig.)

  1. Deconstructing the Tower of London: alternative moves and conflict resolution as predictors of task performance.

    Science.gov (United States)

    Carder, Hassina; Handley, Simon; Perfect, Timothy

    2004-11-01

    Despite widespread use the cognitive demands of the five-disc Tower of London (TOL) are unknown. Research suggests that conflict moves (those that are essential to the solution but do not place a disc in its final position) are a key aspect of performance. These were examined in three studies via a verification paradigm, in which normal participants were asked to decide whether a demonstrated move was correct. Experiment 1 showed that individual move latencies increase with the number of intermediate moves until the disc is placed in its goal position (resolution). Post hoc tests suggested that the number of alternative moves and moves to resolve a disc were independent predictors of performance. Experiment 2 successfully manipulated these factors in an experimental design. Experiment 3 showed that they remain determinants of performance as familiarity increased. Overall, errors on the task were significantly correlated with spatial memory. The implications of these findings for the use of the TOLin cognitive psychology and as an assessment tool are discussed.

  2. Micro-Doppler Ambiguity Resolution Based on Short-Time Compressed Sensing

    Directory of Open Access Journals (Sweden)

    Jing-bo Zhuang

    2015-01-01

    Full Text Available When using a long range radar (LRR to track a target with micromotion, the micro-Doppler embodied in the radar echoes may suffer from ambiguity problem. In this paper, we propose a novel method based on compressed sensing (CS to solve micro-Doppler ambiguity. According to the RIP requirement, a sparse probing pulse train with its transmitting time random is designed. After matched filtering, the slow-time echo signals of the micromotion target can be viewed as randomly sparse sampling of Doppler spectrum. Select several successive pulses to form a short-time window and the CS sensing matrix can be built according to the time stamps of these pulses. Then performing Orthogonal Matching Pursuit (OMP, the unambiguous micro-Doppler spectrum can be obtained. The proposed algorithm is verified using the echo signals generated according to the theoretical model and the signals with micro-Doppler signature produced using the commercial electromagnetic simulation software FEKO.

  3. FRANCHISOR-FRANCHISEE RELATIONSHIP QUALITY: TIME OF RELATIONSHIP AND PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Luís Fernando Varotto

    2016-11-01

    Full Text Available Franchise literature disputes how the relationship between franchisors and franchisees develops over time. Traditional lifecycle theory views relationships following an ascendant curve, in which relationship quality and performance strengthen over time. Another perspective better reflects the peculiarities of the franchisor-franchisee relationship, indicating that relationship quality in franchise systems follows a U-shaped curve. There is also limited research on the moderating effect of time on the relationship between relational variables and outcomes. This study sheds light on the influence of relationship duration on relationship quality and financial performance in the franchisee-franchisor relationship. Using a self-report survey from a sample of 342 franchisees, mean and regression analyses are conducted to test relationships. Results confirm the time effect on franchisor-franchisee relationship quality and performance, but the hypothesized shape of relationship phases is only partially confirmed. Moreover, time has a positive moderating effect on the impact of relationship quality on financial performance.

  4. Comparative analysis of time efficiency and spatial resolution between different EIT reconstruction algorithms

    International Nuclear Information System (INIS)

    Kacarska, Marija; Loskovska, Suzana

    2002-01-01

    In this paper comparative analysis between different EIT algorithms is presented. Analysis is made for spatial and temporal resolution of obtained images by several different algorithms. Discussions consider spatial resolution dependent on data acquisition method, too. Obtained results show that conventional applied-current EIT is more powerful compared to induced-current EIT. (Author)

  5. Sub-100 ps coincidence time resolution for positron emission tomography with LSO:Ce codoped with Ca

    CERN Document Server

    Nemallapudi, Mythra Varun; Lecoq, Paul; Auffray, Etiennette; Ferri, Alessandro; Gola, Alberto; Piemonte, Claudio

    2015-01-01

    The coincidence time resolution (CTR) becomes a key parameter of 511keV gamma detection in time of flight positron emission tomography (TOF-PET). This is because additional information obtained through timing leads to a better noise suppression and therefore a better signal to noise ratio in the reconstructed image. In this paper we present the results of CTR measurements on two different SiPM technologies from FBK coupled to LSO:Ce codoped 0.4%Ca crystals. We compare the measurements performed at two separate test setups, i.e. at CERN and at FBK, showing that the obtained results agree within a few percent. We achieve a best CTR value of 85  ±  4 ps FWHM for 2  ×  2  ×  3 mm3 LSO:Ce codoped 0.4%Ca crystals, thus breaking the 100 ps barrier with scintillators similar to LSO:Ce or LYSO:Ce. We also demonstrate that a CTR of 140  ±  5 ps can be achieved for longer 2  ×  2  ×  20 mm3 crystals, which can readily be implemented in the current generation PET syst...

  6. Benchmarking flood models from space in near real-time: accommodating SRTM height measurement errors with low resolution flood imagery

    Science.gov (United States)

    Schumann, G.; di Baldassarre, G.; Alsdorf, D.; Bates, P. D.

    2009-04-01

    In February 2000, the Shuttle Radar Topography Mission (SRTM) measured the elevation of most of the Earth's surface with spatially continuous sampling and an absolute vertical accuracy greater than 9 m. The vertical error has been shown to change with topographic complexity, being less important over flat terrain. This allows water surface slopes to be measured and associated discharge volumes to be estimated for open channels in large basins, such as the Amazon. Building on these capabilities, this paper demonstrates that near real-time coarse resolution radar imagery of a recent flood event on a 98 km reach of the River Po (Northern Italy) combined with SRTM terrain height data leads to a water slope remarkably similar to that derived by combining the radar image with highly accurate airborne laser altimetry. Moreover, it is shown that this space-borne flood wave approximation compares well to a hydraulic model and thus allows the performance of the latter, calibrated on a previous event, to be assessed when applied to an event of different magnitude in near real-time. These results are not only of great importance to real-time flood management and flood forecasting but also support the upcoming Surface Water and Ocean Topography (SWOT) mission that will routinely provide water levels and slopes with higher precision around the globe.

  7. Lognormal switching times for titanium dioxide bipolar memristors: origin and resolution

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros-Ribeiro, Gilberto; Perner, Frederick; Carter, Richard; Abdalla, Hisham; Pickett, Matthew D; Williams, R Stanley [Hewlett-Packard Laboratories, 1501 Page Mill Road, MS 1123 Palo Alto, CA 94304 (United States)

    2011-03-04

    We measured the switching time statistics for a TiO{sub 2} memristor and found that they followed a lognormal distribution, which is a potentially serious problem for computer memory and data storage applications. We examined the underlying physical phenomena that determine the switching statistics and proposed a simple analytical model for the distribution based on the drift/diffusion equation and previously measured nonlinear drift behavior. We designed a closed-loop switching protocol that dramatically narrows the time distribution, which can significantly improve memory circuit performance and reliability.

  8. A Kalman Filter-Based Method to Generate Continuous Time Series of Medium-Resolution NDVI Images

    Directory of Open Access Journals (Sweden)

    Fernando Sedano

    2014-12-01

    Full Text Available A data assimilation method to produce complete temporal sequences of synthetic medium-resolution images is presented. The method implements a Kalman filter recursive algorithm that integrates medium and moderate resolution imagery. To demonstrate the approach, time series of 30-m spatial resolution NDVI images at 16-day time steps were generated using Landsat NDVI images and MODIS NDVI products at four sites with different ecosystems and land cover-land use dynamics. The results show that the time series of synthetic NDVI images captured seasonal land surface dynamics and maintained the spatial structure of the landscape at higher spatial resolution. The time series of synthetic medium-resolution NDVI images were validated within a Monte Carlo simulation framework. Normalized residuals decreased as the number of available observations increased, ranging from 0.2 to below 0.1. Residuals were also significantly lower for time series of synthetic NDVI images generated at combined recursion (smoothing than individually at forward and backward recursions (filtering. Conversely, the uncertainties of the synthetic images also decreased when the number of available observations increased and combined recursions were implemented.

  9. Performance evaluation of novel LaBr{sub 3}(Ce) scintillator geometries for fast-timing applications

    Energy Technology Data Exchange (ETDEWEB)

    Vedia, V., E-mail: mv.vedia@ucm.es [Grupo de Física Nuclear, Facultad de CC. Físicas, Universidad Complutense, CEI Moncloa, 28040 Madrid (Spain); Carmona-Gallardo, M.; Fraile, L.M. [Grupo de Física Nuclear, Facultad de CC. Físicas, Universidad Complutense, CEI Moncloa, 28040 Madrid (Spain); Mach, H. [Grupo de Física Nuclear, Facultad de CC. Físicas, Universidad Complutense, CEI Moncloa, 28040 Madrid (Spain); National Centre for Nuclear Research, Division for Nuclear Physics, BP1, Warsaw (Poland); Udías, J.M. [Grupo de Física Nuclear, Facultad de CC. Físicas, Universidad Complutense, CEI Moncloa, 28040 Madrid (Spain)

    2017-06-11

    We evaluate the performance of two LaBr{sub 3}(Ce) crystals that were produced with special geometries, aimed at enhancing the scintillation light collection and thus the time resolution. Their design was motivated by the construction of high-performance fast-timing arrays like the FAst TIMing array for DESPEC (FATIMA), which demands a high packing factor in addition to good time and energy resolutions. Energy resolution and efficiency were measured using standard calibration sources. Timing measurements were performed at {sup 60}Co and {sup 22}Na γ-energies against a fast BaF{sub 2} reference detector. The time resolution was optimized by the choice of the photomultiplier bias voltage and the fine tuning of the constant fraction discriminator parameters. Monte Carlo simulations using the Geant4 toolkit were performed in order to achieve a better understanding of how the new geometries affect the light transport and thus the performance of the crystals. It is found that the conical-shaped LaBr{sub 3}(Ce) crystals are optimal for fast-timing applications and for the construction of arrays such as FATIMA.

  10. High-resolution X-ray emission spectroscopy with transition-edge sensors: present performance and future potential

    Energy Technology Data Exchange (ETDEWEB)

    Uhlig, J.; Doriese, W. B.; Fowler, J. W.; Swetz, D. S.; Jaye, C.; Fischer, D. A.; Reintsema, C. D.; Bennett, D. A.; Vale, L. R.; Mandal, U.; O' Neil, G. C.; Miaja-Avila, L.; Joe, Y. I.; El Nahhas, A.; Fullagar, W.; Parnefjord Gustafsson, F.; Sundström, V.; Kurunthu, D.; Hilton, G. C.; Schmidt, D. R.; Ullom, J. N.

    2015-04-21

    X-ray emission spectroscopy (XES) is a powerful element-selective tool to analyze the oxidation states of atoms in complex compounds, determine their electronic configuration, and identify unknown compounds in challenging environments. Until now the low efficiency of wavelength-dispersive X-ray spectrometer technology has limited the use of XES, especially in combination with weaker laboratory X-ray sources. More efficient energy-dispersive detectors have either insufficient energy resolution because of the statistical limits described by Fano or too low counting rates to be of practical use. This paper updates an approach to high-resolution X-ray emission spectroscopy that uses a microcalorimeter detector array of superconducting transition-edge sensors (TESs). TES arrays are discussed and compared with conventional methods, and shown under which circumstances they are superior. It is also shown that a TES array can be integrated into a table-top time-resolved X-ray source and a soft X-ray synchrotron beamline to perform emission spectroscopy with good chemical sensitivity over a very wide range of energies.

  11. Mapping the Dissociative Ionization Dynamics of Molecular Nitrogen with Attosecond Time Resolution

    Directory of Open Access Journals (Sweden)

    A. Trabattoni

    2015-12-01

    Full Text Available Studying the interaction of molecular nitrogen with extreme ultraviolet (XUV radiation is of prime importance to understand radiation-induced processes occurring in Earth’s upper atmosphere. In particular, photoinduced dissociation dynamics involving excited states of N_{2}^{+} leads to N and N^{+} atomic species that are relevant in atmospheric photochemical processes. However, tracking the relaxation dynamics of highly excited states of N_{2}^{+} is difficult to achieve, and its theoretical modeling is notoriously complex. Here, we report on an experimental and theoretical investigation of the dissociation dynamics of N_{2}^{+} induced by isolated attosecond XUV pulses in combination with few-optical-cycle near-infrared/visible (NIR/VIS pulses. The momentum distribution of the produced N^{+} fragments is measured as a function of pump-probe delay with subfemtosecond resolution using a velocity map imaging spectrometer. The time-dependent measurements reveal the presence of NIR/VIS-induced transitions between N_{2}^{+} states together with an interference pattern that carries the signature of the potential energy curves activated by the XUV pulse. We show that the subfemtosecond characterization of the interference pattern is essential for a semiquantitative determination of the repulsive part of these curves.

  12. Observation of human embryonic behavior in vitro by high-resolution time-lapse cinematography.

    Science.gov (United States)

    Iwata, Kyoko; Mio, Yasuyuki

    2016-07-01

    Assisted reproductive technology (ART) has yielded vast amounts of information and knowledge on human embryonic development in vitro; however, still images provide limited data on dynamic changes in the developing embryos. Using our high-resolution time-lapse cinematography (hR-TLC) system, we were able to describe normal human embryonic development continuously from the fertilization process to the hatched blastocyst stage in detail. Our hR-TLC observation also showed the embryonic abnormality of a third polar body (PB)-like substance likely containing a small pronucleus being extruded and resulting in single-pronucleus (1PN) formation, while our molecular biological investigations suggested the possibility that some 1PN embryos could be diploid, carrying both maternal and paternal genomes. Furthermore, in some embryos the extruded third PB-like substance was eventually re-absorbed into the ooplasm resulting in the formation of an uneven-sized, two-PN zygote. In addition, other hR-TLC observations showed that cytokinetic failure was correlated with equal-sized, multi-nucleated blastomeres that were also observed in the embryo showing early initiation of compaction. Assessment combining our hR-TLC with molecular biological techniques enables a better understanding of embryonic development and potential improvements in ART outcomes.

  13. Augmented Reality Experience: From High-Resolution Acquisition to Real Time Augmented Contents

    Directory of Open Access Journals (Sweden)

    Paolo Clini

    2014-01-01

    Full Text Available This paper presents results of a research project “dUcale” that experiments ICT solutions for the museum of Palazzo Ducale (Urbino. In this project, the famed painting the “Città Ideale” becomes a case to exemplify a specific approach to the digital mediation of cultural heritage. An augmented reality (AR mobile application, able to enhance the museum visit experience, is presented. The computing technologies involved in the project (websites, desktop and social applications, mobile software, and AR constitute a persuasive environment for the artwork knowledge. The overall goal of our research is to provide to cultural institutions best practices efficiently on low budgets. Therefore, we present a low cost method for high-resolution acquisition of paintings; the image is used as a base in AR approach. The proposed methodology consists of an improved SIFT extractor for real time image. The other novelty of this work is the multipoint probabilistic layer. Experimental results demonstrated the robustness of the proposed approach with extensive use of the AR application in front of the “Città Ideale” painting. To prove the usability of the application and to ensure a good user experience, we also carried out several users tests in the real scenario.

  14. Performance of CMS hadron calorimeter timing and synchronization using test beam, cosmic ray, and LHC beam data

    CERN Document Server

    Chatrchyan, S; Sirunyan, A M; Adam, W; Arnold, B; Bergauer, H; Bergauer, T; Dragicevic, M; Eichberger, M; Erö, J; Friedl, M; Frühwirth, R; Ghete, V M; Hammer, J; Hänsel, S; Hoch, M; Hörmann, N; Hrubec, J; Jeitler, M; Kasieczka, G; Kastner, K; Krammer, M; Liko, D; Magrans de Abril, I; Mikulec, I; Mittermayr, F; Neuherz, B; Oberegger, M; Padrta, M; Pernicka, M; Rohringer, H; Schmid, S; Schöfbeck, R; Schreiner, T; Stark, R; Steininger, H; Strauss, J; Taurok, A; Teischinger, F; Themel, T; Uhl, D; Wagner, P; Waltenberger, W; Walzel, G; Widl, E; Wulz, C E; Chekhovsky, V; Dvornikov, O; Emeliantchik, I; Litomin, A; Makarenko, V; Marfin, I; Mossolov, V; Shumeiko, N; Solin, A; Stefanovitch, R; Suarez Gonzalez, J; Tikhonov, A; Fedorov, A; Karneyeu, A; Korzhik, M; Panov, V; Zuyeuski, R; Kuchinsky, P; Beaumont, W; Benucci, L; Cardaci, M; De Wolf, E A; Delmeire, E; Druzhkin, D; Hashemi, M; Janssen, X; Maes, T; Mucibello, L; Ochesanu, S; Rougny, R; Selvaggi, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Adler, V; Beauceron, S; Blyweert, S; D'Hondt, J; De Weirdt, S; Devroede, O; Heyninck, J; Kalogeropoulos, A; Maes, J; Maes, M; Mozer, M U; Tavernier, S; Van Doninck, W; Van Mulders, P; Villella, I; Bouhali, O; Chabert, E C; Charaf, O; Clerbaux, B; De Lentdecker, G; Dero, V; Elgammal, S; Gay, A P R; Hammad, G H; Marage, P E; Rugovac, S; Vander Velde, C; Vanlaer, P; Wickens, J; Grunewald, M; Klein, B; Marinov, A; Ryckbosch, D; Thyssen, F; Tytgat, M; Vanelderen, L; Verwilligen, P; Basegmez, S; Bruno, G; Caudron, J; Delaere, C; Demin, P; Favart, D; Giammanco, A; Grégoire, G; Lemaitre, V; Militaru, O; Ovyn, S; Piotrzkowski, K; Quertenmont, L; Schul, N; Beliy, N; Daubie, E; Alves, G A; Pol, M E; Souza, M H G; Carvalho, W; De Jesus Damiao, D; De Oliveira Martins, C; Fonseca De Souza, S; Mundim, L; Oguri, V; Santoro, A; Silva Do Amaral, S M; Sznajder, A; Fernandez Perez Tomei, T R; Ferreira Dias, M A; Gregores, E M; Novaes, S F; Abadjiev, K; Anguelov, T; Damgov, J; Darmenov, N; Dimitrov, L; Genchev, V; Iaydjiev, P; Piperov, S; Stoykova, S; Sultanov, G; Trayanov, R; Vankov, I; Dimitrov, A; Dyulendarova, M; Kozhuharov, V; Litov, L; Marinova, E; Mateev, M; Pavlov, B; Petkov, P; Toteva, Z; Chen, G M; Chen, H S; Guan, W; Jiang, C H; Liang, D; Liu, B; Meng, X; Tao, J; Wang, J; Wang, Z; Xue, Z; Zhang, Z; Ban, Y; Cai, J; Ge, Y; Guo, S; Hu, Z; Mao, Y; Qian, S J; Teng, H; Zhu, B; Avila, C; Baquero Ruiz, M; Carrillo Montoya, C A; Gomez, A; Gomez Moreno, B; Ocampo Rios, A A; Osorio Oliveros, A F; Reyes Romero, D; Sanabria, J C; Godinovic, N; Lelas, K; Plestina, R; Polic, D; Puljak, I; Antunovic, Z; Dzelalija, M; Brigljevic, V; Duric, S; Kadija, K; Morovic, S; Fereos, R; Galanti, M; Mousa, J; Papadakis, A; Ptochos, F; Razis, P A; Tsiakkouri, D; Zinonos, Z; Hektor, A; Kadastik, M; Kannike, K; Müntel, M; Raidal, M; Rebane, L; Anttila, E; Czellar, S; Härkönen, J; Heikkinen, A; Karimäki, V; Kinnunen, R; Klem, J; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Mäenpää, T; Nysten, J; Tuominen, E; Tuominiemi, J; Ungaro, D; Wendland, L; Banzuzi, K; Korpela, A; Tuuva, T; Nedelec, P; Sillou, D; Besancon, M; Chipaux, R; Dejardin, M; Denegri, D; Descamps, J; Fabbro, B; Faure, J L; Ferri, F; Ganjour, S; Gentit, F X; Givernaud, A; Gras, P; Hamel de Monchenault, G; Jarry, P; Lemaire, M C; Locci, E; Malcles, J; Marionneau, M; Millischer, L; Rander, J; Rosowsky, A; Rousseau, D; Titov, M; Verrecchia, P; Baffioni, S; Bianchini, L; Bluj, M; Busson, P; Charlot, C; Dobrzynski, L; Granier de Cassagnac, R; Haguenauer, M; Miné, P; Paganini, P; Sirois, Y; Thiebaux, C; Zabi, A; Agram, J L; Besson, A; Bloch, D; Bodin, D; Brom, J M; Conte, E; Drouhin, F; Fontaine, J C; Gelé, D; Goerlach, U; Gross, L; Juillot, P; Le Bihan, A C; Patois, Y; Speck, J; Van Hove, P; Baty, C; Bedjidian, M; Blaha, J; Boudoul, G; Brun, H; Chanon, N; Chierici, R; Contardo, D; Depasse, P; Dupasquier, T; El Mamouni, H; Fassi, F; Fay, J; Gascon, S; Ille, B; Kurca, T; Le Grand, T; Lethuillier, M; Lumb, N; Mirabito, L; Perries, S; Vander Donckt, M; Verdier, P; Djaoshvili, N; Roinishvili, N; Roinishvili, V; Amaglobeli, N; Adolphi, R; Anagnostou, G; Brauer, R; Braunschweig, W; Edelhoff, M; Esser, H; Feld, L; Karpinski, W; Khomich, A; Klein, K; Mohr, N; Ostaptchouk, A; Pandoulas, D; Pierschel, G; Raupach, F; Schael, S; Schultz von Dratzig, A; Schwering, G; Sprenger, D; Thomas, M; Weber, M; Wittmer, B; Wlochal, M; Actis, O; Altenhöfer, G; Bender, W; Biallass, P; Erdmann, M; Fetchenhauer, G; Frangenheim, J; Hebbeker, T; Hilgers, G; Hinzmann, A; Hoepfner, K; Hof, C; Kirsch, M; Klimkovich, T; Kreuzer, P; Lanske, D; Merschmeyer, M; Meyer, A; Philipps, B; Pieta, H; Reithler, H; Schmitz, S A; Sonnenschein, L; Sowa, M; Steggemann, J; Szczesny, H; Teyssier, D; Zeidler, C; Bontenackels, M; Davids, M; Duda, M; Flügge, G; Geenen, H; Giffels, M; Haj Ahmad, W; Hermanns, T; Heydhausen, D; Kalinin, S; Kress, T; Linn, A; Nowack, A; Perchalla, L; Poettgens, M; Pooth, O; Sauerland, P; Stahl, A; Tornier, D; Zoeller, M H; Aldaya Martin, M; Behrens, U; Borras, K; Campbell, A; Castro, E; Dammann, D; Eckerlin, G; Flossdorf, A; Flucke, G; Geiser, A; Hatton, D; Hauk, J; Jung, H; Kasemann, M; Katkov, I; Kleinwort, C; Kluge, H; Knutsson, A; Kuznetsova, E; Lange, W; Lohmann, W; Mankel, R; Marienfeld, M; Meyer, A B; Miglioranzi, S; Mnich, J; Ohlerich, M; Olzem, J; Parenti, A; Rosemann, C; Schmidt, R; Schoerner-Sadenius, T; Volyanskyy, D; Wissing, C; Zeuner, W D; Autermann, C; Bechtel, F; Draeger, J; Eckstein, D; Gebbert, U; Kaschube, K; Kaussen, G; Klanner, R; Mura, B; Naumann-Emme, S; Nowak, F; Pein, U; Sander, C; Schleper, P; Schum, T; Stadie, H; Steinbrück, G; Thomsen, J; Wolf, R; Bauer, J; Blüm, P; Buege, V; Cakir, A; Chwalek, T; De Boer, W; Dierlamm, A; Dirkes, G; Feindt, M; Felzmann, U; Frey, M; Furgeri, A; Gruschke, J; Hackstein, C; Hartmann, F; Heier, S; Heinrich, M; Held, H; Hirschbuehl, D; Hoffmann, K H; Honc, S; Jung, C; Kuhr, T; Liamsuwan, T; Martschei, D; Mueller, S; Müller, Th; Neuland, M B; Niegel, M; Oberst, O; Oehler, A; Ott, J; Peiffer, T; Piparo, D; Quast, G; Rabbertz, K; Ratnikov, F; Ratnikova, N; Renz, M; Saout, C; Sartisohn, G; Scheurer, A; Schieferdecker, P; Schilling, F P; Schott, G; Simonis, H J; Stober, F M; Sturm, P; Troendle, D; Trunov, A; Wagner, W; Wagner-Kuhr, J; Zeise, M; Zhukov, V; Ziebarth, E B; Daskalakis, G; Geralis, T; Karafasoulis, K; Kyriakis, A; Loukas, D; Markou, A; Markou, C; Mavrommatis, C; Petrakou, E; Zachariadou, A; Gouskos, L; Katsas, P; Panagiotou, A; Evangelou, I; Kokkas, P; Manthos, N; Papadopoulos, I; Patras, V; Triantis, F A; Bencze, G; Boldizsar, L; Debreczeni, G; Hajdu, C; Hernath, S; Hidas, P; Horvath, D; Krajczar, K; Laszlo, A; Patay, G; Sikler, F; Toth, N; Vesztergombi, G; Beni, N; Christian, G; Imrek, J; Molnar, J; Novak, D; Palinkas, J; Szekely, G; Szillasi, Z; Tokesi, K; Veszpremi, V; Kapusi, A; Marian, G; Raics, P; Szabo, Z; Trocsanyi, Z L; Ujvari, B; Zilizi, G; Bansal, S; Bawa, H S; Beri, S B; Bhatnagar, V; Jindal, M; Kaur, M; Kaur, R; Kohli, J M; Mehta, M Z; Nishu, N; Saini, L K; Sharma, A; Singh, A; Singh, J B; Singh, S P; Ahuja, S; Arora, S; Bhattacharya, S; Chauhan, S; Choudhary, B C; Gupta, P; Jain, S; Jha, M; Kumar, A; Ranjan, K; Shivpuri, R K; Srivastava, A K; Choudhury, R K; Dutta, D; Kailas, S; Kataria, S K; Mohanty, A K; Pant, L M; Shukla, P; Topkar, A; Aziz, T; Guchait, M; Gurtu, A; Maity, M; Majumder, D; Majumder, G; Mazumdar, K; Nayak, A; Saha, A; Sudhakar, K; Banerjee, S; Dugad, S; Mondal, N K; Arfaei, H; Bakhshiansohi, H; Fahim, A; Jafari, A; Mohammadi Najafabadi, M; Moshaii, A; Paktinat Mehdiabadi, S; Rouhani, S; Safarzadeh, B; Zeinali, M; Felcini, M; Abbrescia, M; Barbone, L; Chiumarulo, F; Clemente, A; Colaleo, A; Creanza, D; Cuscela, G; De Filippis, N; De Palma, M; De Robertis, G; Donvito, G; Fedele, F; Fiore, L; Franco, M; Iaselli, G; Lacalamita, N; Loddo, F; Lusito, L; Maggi, G; Maggi, M; Manna, N; Marangelli, B; My, S; Natali, S; Nuzzo, S; Papagni, G; Piccolomo, S; Pierro, G A; Pinto, C; Pompili, A; Pugliese, G; Rajan, R; Ranieri, A; Romano, F; Roselli, G; Selvaggi, G; Shinde, Y; Silvestris, L; Tupputi, S; Zito, G; Abbiendi, G; Bacchi, W; Benvenuti, A C; Boldini, M; Bonacorsi, D; Braibant-Giacomelli, S; Cafaro, V D; Caiazza, S S; Capiluppi, P; Castro, A; Cavallo, F R; Codispoti, G; Cuffiani, M; D'Antone, I; Dallavalle, G M; Fabbri, F; Fanfani, A; Fasanella, D; Giacomelli, P; Giordano, V; Giunta, M; Grandi, C; Guerzoni, M; Marcellini, S; Masetti, G; Montanari, A; Navarria, F L; Odorici, F; Pellegrini, G; Perrotta, A; Rossi, A M; Rovelli, T; Siroli, G; Torromeo, G; Travaglini, R; Albergo, S; Costa, S; Potenza, R; Tricomi, A; Tuve, C; Barbagli, G; Broccolo, G; Ciulli, V; Civinini, C; D'Alessandro, R; Focardi, E; Frosali, S; Gallo, E; Genta, C; Landi, G; Lenzi, P; Meschini, M; Paoletti, S; Sguazzoni, G; Tropiano, A; Benussi, L; Bertani, M; Bianco, S; Colafranceschi, S; Colonna, D; Fabbri, F; Giardoni, M; Passamonti, L; Piccolo, D; Pierluigi, D; Ponzio, B; Russo, A; Fabbricatore, P; Musenich, R; Benaglia, A; Calloni, M; Cerati, G B; D'Angelo, P; De Guio, F; Farina, F M; Ghezzi, A; Govoni, P; Malberti, M; Malvezzi, S; Martelli, A; Menasce, D; Miccio, V; Moroni, L; Negri, P; Paganoni, M; Pedrini, D; Pullia, A; Ragazzi, S; Redaelli, N; Sala, S; Salerno, R; Tabarelli de Fatis, T; Tancini, V; Taroni, S; Buontempo, S; Cavallo, N; Cimmino, A; De Gruttola, M; Fabozzi, F; Iorio, A O M; Lista, L; Lomidze, D; Noli, P; Paolucci, P; Sciacca, C; Azzi, P; Bacchetta, N; Barcellan, L; Bellan, P; Bellato, M; Benettoni, M; Biasotto, M; Bisello, D; Borsato, E; Branca, A; Carlin, R; Castellani, L; Checchia, P; Conti, E; Dal Corso, F; De Mattia, M; Dorigo, T; Dosselli, U; Fanzago, F; Gasparini, F; Gasparini, U; Giubilato, P; Gonella, F; Gresele, A; Gulmini, M; Kaminskiy, A; Lacaprara, S; Lazzizzera, I; Margoni, M; Maron, G; Mattiazzo, S; Mazzucato, M; Meneghelli, M; Meneguzzo, A T; Michelotto, M; Montecassiano, F; Nespolo, M; Passaseo, M; Pegoraro, M; Perrozzi, L; Pozzobon, N; Ronchese, P; Simonetto, F; Toniolo, N; Torassa, E; Tosi, M; Triossi, A; Vanini, S; Ventura, S; Zotto, P; Zumerle, G; Baesso, P; Berzano, U; Bricola, S; Necchi, M M; Pagano, D; Ratti, S P; Riccardi, C; Torre, P; Vicini, A; Vitulo, P; Viviani, C; Aisa, D; Aisa, S; Babucci, E; Biasini, M; Bilei, G M; Caponeri, B; Checcucci, B; Dinu, N; Fanò, L; Farnesini, L; Lariccia, P; Lucaroni, A; Mantovani, G; Nappi, A; Piluso, A; Postolache, V; Santocchia, A; Servoli, L; Tonoiu, D; Vedaee, A; Volpe, R; Azzurri, P; Bagliesi, G; Bernardini, J; Berretta, L; Boccali, T; Bocci, A; Borrello, L; Bosi, F; Calzolari, F; Castaldi, R; Dell'Orso, R; Fiori, F; Foà, L; Gennai, S; Giassi, A; Kraan, A; Ligabue, F; Lomtadze, T; Mariani, F; Martini, L; Massa, M; Messineo, A; Moggi, A; Palla, F; Palmonari, F; Petragnani, G; Petrucciani, G; Raffaelli, F; Sarkar, S; Segneri, G; Serban, A T; Spagnolo, P; Tenchini, R; Tolaini, S; Tonelli, G; Venturi, A; Verdini, P G; Baccaro, S; Barone, L; Bartoloni, A; Cavallari, F; Dafinei, I; Del Re, D; Di Marco, E; Diemoz, M; Franci, D; Longo, E; Organtini, G; Palma, A; Pandolfi, F; Paramatti, R; Pellegrino, F; Rahatlou, S; Rovelli, C; Alampi, G; Amapane, N; Arcidiacono, R; Argiro, S; Arneodo, M; Biino, C; Borgia, M A; Botta, C; Cartiglia, N; Castello, R; Cerminara, G; Costa, M; Dattola, D; Dellacasa, G; Demaria, N; Dughera, G; Dumitrache, F; Graziano, A; Mariotti, C; Marone, M; Maselli, S; Migliore, E; Mila, G; Monaco, V; Musich, M; Nervo, M; Obertino, M M; Oggero, S; Panero, R; Pastrone, N; Pelliccioni, M; Romero, A; Ruspa, M; Sacchi, R; Solano, A; Staiano, A; Trapani, P P; Trocino, D; Vilela Pereira, A; Visca, L; Zampieri, A; Ambroglini, F; Belforte, S; Cossutti, F; Della Ricca, G; Gobbo, B; Penzo, A; Chang, S; Chung, J; Kim, D H; Kim, G N; Kong, D J; Park, H; Son, D C; Bahk, S Y; Song, S; Jung, S Y; Hong, B; Kim, H; Kim, J H; Lee, K S; Moon, D H; Park, S K; Rhee, H B; Sim, K S; Kim, J; Choi, M; Hahn, G; Park, I C; Choi, S; Choi, Y; Goh, J; Jeong, H; Kim, T J; Lee, J; Lee, S; Janulis, M; Martisiute, D; Petrov, P; Sabonis, T; Castilla Valdez, H; Sánchez Hernández, A; Carrillo Moreno, S; Morelos Pineda, A; Allfrey, P; Gray, R N C; Krofcheck, D; Bernardino Rodrigues, N; Butler, P H; Signal, T; Williams, J C; Ahmad, M; Ahmed, I; Ahmed, W; Asghar, M I; Awan, M I M; Hoorani, H R; Hussain, I; Khan, W A; Khurshid, T; Muhammad, S; Qazi, S; Shahzad, H; Cwiok, M; Dabrowski, R; Dominik, W; Doroba, K; Konecki, M; Krolikowski, J; Pozniak, K; Romaniuk, Ryszard; Zabolotny, W; Zych, P; Frueboes, T; Gokieli, R; Goscilo, L; Górski, M; Kazana, M; Nawrocki, K; Szleper, M; Wrochna, G; Zalewski, P; Almeida, N; Antunes Pedro, L; Bargassa, P; David, A; Faccioli, P; Ferreira Parracho, P G; Freitas Ferreira, M; Gallinaro, M; Guerra Jordao, M; Martins, P; Mini, G; Musella, P; Pela, J; Raposo, L; Ribeiro, P Q; Sampaio, S; Seixas, J; Silva, J; Silva, P; Soares, D; Sousa, M; Varela, J; Wöhri, H K; Altsybeev, I; Belotelov, I; Bunin, P; Ershov, Y; Filozova, I; Finger, M; Finger, M., Jr.; Golunov, A; Golutvin, I; Gorbounov, N; Kalagin, V; Kamenev, A; Karjavin, V; Konoplyanikov, V; Korenkov, V; Kozlov, G; Kurenkov, A; Lanev, A; Makankin, A; Mitsyn, V V; Moisenz, P; Nikonov, E; Oleynik, D; Palichik, V; Perelygin, V; Petrosyan, A; Semenov, R; Shmatov, S; Smirnov, V; Smolin, D; Tikhonenko, E; Vasil'ev, S; Vishnevskiy, A; Volodko, A; Zarubin, A; Zhiltsov, V; Bondar, N; Chtchipounov, L; Denisov, A; Gavrikov, Y; Gavrilov, G; Golovtsov, V; Ivanov, Y; Kim, V; Kozlov, V; Levchenko, P; Obrant, G; Orishchin, E; Petrunin, A; Shcheglov, Y; Shchetkovskiy, A; Sknar, V; Smirnov, I; Sulimov, V; Tarakanov, V; Uvarov, L; Vavilov, S; Velichko, G; Volkov, S; Vorobyev, A; Andreev, Yu; Anisimov, A; Antipov, P; Dermenev, A; Gninenko, S; Golubev, N; Kirsanov, M; Krasnikov, N; Matveev, V; Pashenkov, A; Postoev, V E; Solovey, A; Toropin, A; Troitsky, S; Baud, A; Epshteyn, V; Gavrilov, V; Ilina, N; Kaftanov, V; Kolosov, V; Kossov, M; Krokhotin, A; Kuleshov, S; Oulianov, A; Safronov, G; Semenov, S; Shreyber, I; Stolin, V; Vlasov, E; Zhokin, A; Boos, E; Dubinin, M; Dudko, L; Ershov, A; Gribushin, A; Klyukhin, V; Kodolova, O; Lokhtin, I; Petrushanko, S; Sarycheva, L; Savrin, V; Snigirev, A; Vardanyan, I; Dremin, I; Kirakosyan, M; Konovalova, N; Rusakov, S V; Vinogradov, A; Akimenko, S; Artamonov, A; Azhgirey, I; Bitioukov, S; Burtovoy, V; Grishin, V; Kachanov, V; Konstantinov, D; Krychkine, V; Levine, A; Lobov, I; Lukanin, V; Mel'nik, Y; Petrov, V; Ryutin, R; Slabospitsky, S; Sobol, A; Sytine, A; Tourtchanovitch, L; Troshin, S; Tyurin, N; Uzunian, A; Volkov, A; Adzic, P; Djordjevic, M; Jovanovic, D; Krpic, D; Maletic, D; Puzovic, J; Smiljkovic, N; Aguilar-Benitez, M; Alberdi, J; Alcaraz Maestre, J; Arce, P; Barcala, J M; Battilana, C; Burgos Lazaro, C; Caballero Bejar, J; Calvo, E; Cardenas Montes, M; Cepeda, M; Cerrada, M; Chamizo Llatas, M; Clemente, F; Colino, N; Daniel, M; De La Cruz, B; Delgado Peris, A; Diez Pardos, C; Fernandez Bedoya, C; Fernández Ramos, J P; Ferrando, A; Flix, J; Fouz, M C; Garcia-Abia, P; 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    2010-01-01

    This paper discusses the design and performance of the time measurement technique and of the synchronization systems of the CMS hadron calorimeter. Timing performance results are presented from the Cosmic Run At Four Tesla and LHC beam runs taken in the Autumn of 2008. For hadronic showers of energy greater than 100 GeV, the timing resolution is measured to be about 1.2 ns. The inter-channel synchronization is measured to be within 2 ns.

  15. High-Resolution Melting System to Perform Multilocus Sequence Typing of Campylobacter jejuni

    Science.gov (United States)

    Lévesque, Simon; Michaud, Sophie; Arbeit, Robert D.; Frost, Eric H.

    2011-01-01

    Multi-locus sequence typing (MLST) has emerged as the state-of-the-art method for resolving bacterial population genetics but it is expensive and time consuming. We evaluated the potential of high resolution melting (HRM) to identify known MLST alleles of Campylobacter jejuni at reduced cost and time. Each MLST locus was amplified in two or three sub fragments, which were analyzed by HRM. The approach was investigated using 47 C. jejuni isolates, previously characterized by classical MLST, representing isolates from diverse environmental, animal and clinical sources and including the six most prevalent sequence types (ST) and the most frequent alleles. HRM was then applied to a validation set of 84 additional C. jejuni isolates from chickens; 92% of the alleles were resolved in 35 hours of laboratory time and the cost of reagents per isolate was $20 compared with $100 for sequence-based typing. HRM has the potential to complement sequence-based methods for resolving SNPs and to facilitate a wide range of genotyping studies. PMID:21297862

  16. High-resolution melting system to perform multilocus sequence typing of Campylobacter jejuni.

    Directory of Open Access Journals (Sweden)

    Simon Lévesque

    Full Text Available Multi-locus sequence typing (MLST has emerged as the state-of-the-art method for resolving bacterial population genetics but it is expensive and time consuming. We evaluated the potential of high resolution melting (HRM to identify known MLST alleles of Campylobacter jejuni at reduced cost and time. Each MLST locus was amplified in two or three sub fragments, which were analyzed by HRM. The approach was investigated using 47 C. jejuni isolates, previously characterized by classical MLST, representing isolates from diverse environmental, animal and clinical sources and including the six most prevalent sequence types (ST and the most frequent alleles. HRM was then applied to a validation set of 84 additional C. jejuni isolates from chickens; 92% of the alleles were resolved in 35 hours of laboratory time and the cost of reagents per isolate was $20 compared with $100 for sequence-based typing. HRM has the potential to complement sequence-based methods for resolving SNPs and to facilitate a wide range of genotyping studies.

  17. High-resolution spectroscopy for Cepheids distance determination. IV. Time series of Hα line profiles

    Science.gov (United States)

    Nardetto, N.; Groh, J. H.; Kraus, S.; Millour, F.; Gillet, D.

    2008-10-01

    Context: In recent years, infrared interferometry has revealed the presence of faint dusty circumstellar envelopes (CSE) around Cepheids. However the size, shape, chemical nature, and the interaction of the CSE with the star itself are still under investigation. The presence of a CSE might have an effect on the angular diameter estimates used in the interferometric Baade-Wesselink and surface-brightness methods of determining the distance of Cepheids. Aims: By studying Hα profiles as a function of the period, we investigate the permanent mass loss and the CSE around Cepheids. Our high spectral- and time-resolution data, combined with a very good S/N, will be useful in constraining future hydrodynamical models of Cepheids atmosphere and their close environment. Methods: We present HARPS (High Accuracy Radial velocity Planetary Search project developed by the European Southern Observatory.) high-resolution spectroscopy (R = 120 000) of eight galactic Cepheids: R Tra, S Cru, Y Sgr, β Dor, zeta Gem, RZ Vel, ell Car, and RS Pup, providing a good period sampling (P = 3.39 d to P = 41.52 d). The Hα line profiles are described for all stars using a 2D (wavelength versus pulsation phase) representation. For each star, an average spectral line profile is derived, together with its first moment (γ-velocity) and its asymmetry (γ-asymmetry). Results: Short-period Cepheids show Hα line profiles following the pulsating envelope of the star, while long-period Cepheids show very complex line profiles and, in particular, large asymmetries. We find a new relationship between the period of Cepheids and their γ-velocities and -asymmetries. These results may be related to the dynamical structure of the atmosphere and to a permanent mass loss of Cepheids. In particular, we confirm for ell Car a dominant absorption component whose velocity is constant and nearly of zero km s-1 in the stellar rest frame. This component is attributed to the presence of circumstellar envelope

  18. How can audiovisual pathways enhance the temporal resolution of time-compressed speech in blind subjects?

    Directory of Open Access Journals (Sweden)

    Ingo eHertrich

    2013-08-01

    Full Text Available In blind people, the visual channel cannot assist face-to-face communication via lipreading or visual prosody. Nevertheless, the visual system may enhance the evaluation of auditory information due to its cross-links to (1 the auditory system, (2 supramodal representations, and (3 frontal action-related areas. Apart from feedback or top-down support of, for example, the processing of spatial or phonological representations, experimental data have shown that the visual system can impact auditory perception at more basic computational stages such as temporal resolution. For example, blind as compared to sighted subjects are more resistant against backward masking, and this ability appears to be associated with activity in visual cortex. Regarding the comprehension of continuous speech, blind subjects can learn to use accelerated text-to-speech systems for "reading" texts at ultra-fast speaking rates (> 16 syllables/s, exceeding by far the normal range of 6 syllables/s. An fMRI study has shown that this ability, among other brain regions, significantly covaries with BOLD responses in bilateral pulvinar, right visual cortex, and left supplementary motor area. Furthermore, magnetoencephalographic (MEG measurements revealed a particular component in right occipital cortex phase-locked to the syllable onsets of accelerated speech. In sighted people, the "bottleneck" for understanding time-compressed speech seems related to a demand for buffering phonological material and is, presumably, linked to frontal brain structures. On the other hand, the neurophysiological correlates of functions overcoming this bottleneck, seem to depend upon early visual cortex activity. The present Hypothesis and Theory paper outlines a model that aims at binding these data together, based on early cross-modal pathways that are already known from various audiovisual experiments considering cross-modal adjustments in space, time, and object recognition.

  19. High Time-Resolution 640-Gb/s Clock Recovery Using Time-Domain Optical Fourier Transformation and Narrowband Optical Filter

    DEFF Research Database (Denmark)

    Guan, P.; Mulvad, Hans Christian Hansen; Kasai, K.

    2010-01-01

    We present a novel scheme for subharmonic clock recovery from an optical time-division-multiplexing signal using time-domain optical Fourier transformation and a narrowband optical filter. High-resolution 640-Gb/s clock recovery is successfully demonstrated with no pattern dependence. The clock...

  20. High Time Resolution Measurements of VOCs from Vehicle Cold Starts: The Air Toxic Cold Start Pulse

    Science.gov (United States)

    Jobson, B. T.; Huangfu, Y.; Vanderschelden, G. S.

    2017-12-01

    Pollutants emitted during motor vehicle cold starts, especially in winter in some climates, is a significant source of winter time air pollution. While data exist for CO, NO, and total hydrocarbon emissions from federal testing procedures for vehicle emission certification, little is known about the emission rates of individual volatile organic compounds, in particular the air toxics benzene, formaldehyde, and acetaldehyde. Little is known about the VOC speciation and temperature dependence for cold starts. The US EPA vehicle emission model MOVES assumes that cold start emissions have the same speciation profile as running emissions. We examined this assumption by measuring cold start exhaust composition for 4 vehicles fueled with E10 gasoline over a temperature range of -4°C to 10°C in winter of 2015. The extra cold start emissions were determined by comparison with emissions during engine idling. In addition to CO and NOx measurements a proton transfer reaction mass spectrometer was used to measure formaldehyde, acetaldehyde, benzene, toluene, and C2-alkylbenzenes at high time resolution to compare with the cold start emission speciation profiles used in the EPA MOVES2014 model. The results show that after the vehicle was started, CO mixing ratios can reach a few percent of the exhaust and then drop to several ppmv within 2 minutes of idling, while NOx showed different temporal behaviors among the four vehicles. VOCs displayed elevated levels during cold start and the peak mixing ratios can be two orders higher than idling phase levels. Molar emission ratios relative to toluene were used to compare with the emission ratio used in MOVES2014 and we found the formaldehyde-to-toluene emission ratio was about 0.19, which is 5 times higher than the emission ratio used in MOVES2014 and the acetaldehyde-to-toluene emission ratios were 0.86-0.89, which is 8 times higher than the ones in MOVES2014. The C2-alkylbenzene-to-toluene ratio agreed well with moves. Our results

  1. Performance Assessment of High Resolution Airborne Full Waveform LiDAR for Shallow River Bathymetry

    Directory of Open Access Journals (Sweden)

    Zhigang Pan

    2015-04-01

    Full Text Available We evaluate the performance of full waveform LiDAR decomposition algorithms with a high-resolution single band airborne LiDAR bathymetry system in shallow rivers. A continuous wavelet transformation (CWT is proposed and applied in two fluvial environments, and the results are compared to existing echo retrieval methods. LiDAR water depths are also compared to independent field measurements. In both clear and turbid water, the CWT algorithm outperforms the other methods if only green LiDAR observations are available. However, both the definition of the water surface, and the turbidity of the water significantly influence the performance of the LiDAR bathymetry observations. The results suggest that there is no single best full waveform processing algorithm for all bathymetric situations. Overall, the optimal processing strategies resulted in a determination of water depths with a 6 cm mean at 14 cm standard deviation for clear water, and a 16 cm mean and 27 cm standard deviation in more turbid water.

  2. Novel Super-Resolution Approach to Time-Resolved Volumetric 4-Dimensional Magnetic Resonance Imaging With High Spatiotemporal Resolution for Multi-Breathing Cycle Motion Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Li, Guang, E-mail: lig2@mskcc.org [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York (United States); Wei, Jie [Department of Computer Science, City College of New York, New York, New York (United States); Kadbi, Mo [Philips Healthcare, MR Therapy Cleveland, Ohio (United States); Moody, Jason; Sun, August; Zhang, Shirong; Markova, Svetlana; Zakian, Kristen; Hunt, Margie; Deasy, Joseph O. [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York (United States)

    2017-06-01

    Purpose: To develop and evaluate a super-resolution approach to reconstruct time-resolved 4-dimensional magnetic resonance imaging (TR-4DMRI) with a high spatiotemporal resolution for multi-breathing cycle motion assessment. Methods and Materials: A super-resolution approach was developed to combine fast 3-dimensional (3D) cine MRI with low resolution during free breathing (FB) and high-resolution 3D static MRI during breath hold (BH) using deformable image registration. A T1-weighted, turbo field echo sequence, coronal 3D cine acquisition, partial Fourier approximation, and SENSitivity Encoding parallel acceleration were used. The same MRI pulse sequence, field of view, and acceleration techniques were applied in both FB and BH acquisitions; the intensity-based Demons deformable image registration method was used. Under an institutional review board–approved protocol, 7 volunteers were studied with 3D cine FB scan (voxel size: 5 × 5 × 5 mm{sup 3}) at 2 Hz for 40 seconds and a 3D static BH scan (2 × 2 × 2 mm{sup 3}). To examine the image fidelity of 3D cine and super-resolution TR-4DMRI, a mobile gel phantom with multi-internal targets was scanned at 3 speeds and compared with the 3D static image. Image similarity among 3D cine, 4DMRI, and 3D static was evaluated visually using difference image and quantitatively using voxel intensity correlation and Dice index (phantom only). Multi-breathing-cycle waveforms were extracted and compared in both phantom and volunteer images using the 3D cine as the references. Results: Mild imaging artifacts were found in the 3D cine and TR-4DMRI of the mobile gel phantom with a Dice index of >0.95. Among 7 volunteers, the super-resolution TR-4DMRI yielded high voxel-intensity correlation (0.92 ± 0.05) and low voxel-intensity difference (<0.05). The detected motion differences between TR-4DMRI and 3D cine were −0.2 ± 0.5 mm (phantom) and −0.2 ± 1.9 mm (diaphragms). Conclusion: Super-resolution TR-4

  3. Reviewing real-time performance of nuclear reactor safety systems

    Energy Technology Data Exchange (ETDEWEB)

    Preckshot, G.G. [Lawrence Livermore National Lab., CA (United States)

    1993-08-01

    The purpose of this paper is to recommend regulatory guidance for reviewers examining real-time performance of computer-based safety systems used in nuclear power plants. Three areas of guidance are covered in this report. The first area covers how to determine if, when, and what prototypes should be required of developers to make a convincing demonstration that specific problems have been solved or that performance goals have been met. The second area has recommendations for timing analyses that will prove that the real-time system will meet its safety-imposed deadlines. The third area has description of means for assessing expected or actual real-time performance before, during, and after development is completed. To ensure that the delivered real-time software product meets performance goals, the paper recommends certain types of code-execution and communications scheduling. Technical background is provided in the appendix on methods of timing analysis, scheduling real-time computations, prototyping, real-time software development approaches, modeling and measurement, and real-time operating systems.

  4. A Process For Performance Evaluation Of Real-Time Systems

    Directory of Open Access Journals (Sweden)

    Andrew J. Kornecki

    2003-12-01

    Full Text Available Real-time developers and engineers must not only meet the system functional requirements, but also the stringent timing requirements. One of the critical decisions leading to meeting these timing requirements is the selection of an operating system under which the software will be developed and run. Although there is ample documentation on real-time systems performance and evaluation, little can be found that combines such information into an efficient process for use by developers. As the software industry moves towards clearly defined processes, creation of appropriate guidelines describing a process for performance evaluation of real-time system would greatly benefit real-time developers. This technology transition research focuses on developing such a process. PROPERT (PROcess for Performance Evaluation of Real Time systems - the process described in this paper - is based upon established techniques for evaluating real-time systems. It organizes already existing real-time performance criteria and assessment techniques in a manner consistent with a well-formed process, based on the Personal Software Process concepts.

  5. Reviewing real-time performance of nuclear reactor safety systems

    International Nuclear Information System (INIS)

    Preckshot, G.G.

    1993-08-01

    The purpose of this paper is to recommend regulatory guidance for reviewers examining real-time performance of computer-based safety systems used in nuclear power plants. Three areas of guidance are covered in this report. The first area covers how to determine if, when, and what prototypes should be required of developers to make a convincing demonstration that specific problems have been solved or that performance goals have been met. The second area has recommendations for timing analyses that will prove that the real-time system will meet its safety-imposed deadlines. The third area has description of means for assessing expected or actual real-time performance before, during, and after development is completed. To ensure that the delivered real-time software product meets performance goals, the paper recommends certain types of code-execution and communications scheduling. Technical background is provided in the appendix on methods of timing analysis, scheduling real-time computations, prototyping, real-time software development approaches, modeling and measurement, and real-time operating systems

  6. Performance evaluation of near-real-time accounting systems

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    Examples are given illustrating the application of near-real-time accounting concepts and principles to actual nuclear facilities. Experience with prototypical systems at the AGNS reprocessing plant and the Los Alamos plutonium facility is described using examples of actual data to illustrate the performance and effectiveness of near-real-time systems. The purpose of the session is to enable participants to: (1) identify the major components of near-real-time accounting systems; (2) describe qualitatively the advantages, limitations, and performance of such systems in real nuclear facilities; (3) identify process and facility design characteristics that affect the performance of near-real-time systems; and (4) describe qualitatively the steps necessary to implement a near-real-time accounting and control system in a nuclear facility

  7. Towards real-time feedback in high performance speed skating

    NARCIS (Netherlands)

    van der Eb, Jeroen; Zandee, Willem; van den Bogaard, Timo; Geraets, Sjoerd; Veeger, H.E.J.; Beek, Peter; Potthast, Wolfgang; Niehoff, Anja; David, Sina

    2017-01-01

    The aim of the current study is to evaluate several performance indicators to be used as real-time feedback in the coming experiments to enhance performance of elite speeds skaters. Six speed skaters, wearing one IMU per skate, collected data over one full training season to evaluate and pinpoint

  8. Improvements in localized proton NMR spectroscopy of human brain. Water suppression, short echo times, and 1 ml resolution

    Science.gov (United States)

    Frahm, J.; Michaelis, T.; Merboldt, K. D.; Bruhn, H.; Gyngell, M. L.; Hänicke, W.

    Considerable technical improvements are reported for localized proton NMR spectroscopy using stimulated echoes. When compared to previous results, proton NMR spectra of the human brain are now obtainable (i) with in vivo water suppression factors of ⩾1000, (ii) with only minor T2 losses and negligible distortions due to J modulation at short echo times of 10-20 ms, and (iii) from volumes of interest as small as 1-8 ml within measuring times of 1-10 min. As a consequence, the detection of cerebral metabolites is greatly facilitated. This particularly applies to the assignment of those resonances (e.g., glutamate, taurine, inositols) that suffer from strong spin-spin coupling at the field strengths commonly in use for NMR in man. Studies of regional metabolite differences, tissue heterogeneity, and focal lesions in patients benefit from the increased spatial resolution and a concomitant reduction of partial volume effects. Localized proton NMR spectroscopy was performed on young healthy volunteers. Experiments were carried out on a 2.0 T whole-body MRI/MRS system using the standard headcoil for both imaging and spectroscopy.

  9. In-situ high resolution particle sampling by large time sequence inertial spectrometry

    International Nuclear Information System (INIS)

    Prodi, V.; Belosi, F.

    1990-09-01

    In situ sampling is always preferred, when possible, because of the artifacts that can arise when the aerosol has to flow through long sampling lines. On the other hand, the amount of possible losses can be calculated with some confidence only when the size distribution can be measured with a sufficient precision and the losses are not too large. This makes it desirable to sample directly in the vicinity of the aerosol source or containment. High temperature sampling devices with a detailed aerodynamic separation are extremely useful to this purpose. Several measurements are possible with the inertial spectrometer (INSPEC), but not with cascade impactors or cyclones. INSPEC - INertial SPECtrometer - has been conceived to measure the size distribution of aerosols by separating the particles while airborne according to their size and collecting them on a filter. It consists of a channel of rectangular cross-section with a 90 degree bend. Clean air is drawn through the channel, with a thin aerosol sheath injected close to the inner wall. Due to the bend, the particles are separated according to their size, leaving the original streamline by a distance which is a function of particle inertia and resistance, i.e. of aerodynamic diameter. The filter collects all the particles of the same aerodynamic size at the same distance from the inlet, in a continuous distribution. INSPEC particle separation at high temperature (up to 800 C) has been tested with Zirconia particles as calibration aerosols. The feasibility study has been concerned with resolution and time sequence sampling capabilities under high temperature (700 C)

  10. Time assignment system and its performance aboard the Hitomi satellite

    Science.gov (United States)

    Terada, Yukikatsu; Yamaguchi, Sunao; Sugimoto, Shigenobu; Inoue, Taku; Nakaya, Souhei; Murakami, Maika; Yabe, Seiya; Oshimizu, Kenya; Ogawa, Mina; Dotani, Tadayasu; Ishisaki, Yoshitaka; Mizushima, Kazuyo; Kominato, Takashi; Mine, Hiroaki; Hihara, Hiroki; Iwase, Kaori; Kouzu, Tomomi; Tashiro, Makoto S.; Natsukari, Chikara; Ozaki, Masanobu; Kokubun, Motohide; Takahashi, Tadayuki; Kawakami, Satoko; Kasahara, Masaru; Kumagai, Susumu; Angelini, Lorella; Witthoeft, Michael

    2018-01-01

    Fast timing capability in x-ray observation of astrophysical objects is one of the key properties for the ASTRO-H (Hitomi) mission. Absolute timing accuracies of 350 or 35 μs are required to achieve nominal scientific goals or to study fast variabilities of specific sources. The satellite carries a GPS receiver to obtain accurate time information, which is distributed from the central onboard computer through the large and complex SpaceWire network. The details of the time system on the hardware and software design are described. In the distribution of the time information, the propagation delays and jitters affect the timing accuracy. Six other items identified within the timing system will also contribute to absolute time error. These error items have been measured and checked on ground to ensure the time error budgets meet the mission requirements. The overall timing performance in combination with hardware performance, software algorithm, and the orbital determination accuracies, etc. under nominal conditions satisfies the mission requirements of 35 μs. This work demonstrates key points for space-use instruments in hardware and software designs and calibration measurements for fine timing accuracy on the order of microseconds for midsized satellites using the SpaceWire (IEEE1355) network.

  11. Working with Time Management in IT Consulting : Developing a Time Management Strategy by Using Performance Management

    OpenAIRE

    Angermund, Emma; Lindqvist, Emma

    2013-01-01

    Time is in control of our everyday life and work life. Time is a valuable resource of which everyone possesses the same amount. In work life, time is important; it rules the workday and the tasks that are being performed. Time is even more significant within the consultancy industry, where worked time and competence is what is being delivered to the customers. Since time is of great importance for consulting firms, time management systems and time reporting become a crucial part of a consulta...

  12. SU-C-201-04: Noise and Temporal Resolution in a Near Real-Time 3D Dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Rilling, M [Department of physics, engineering physics and optics, Universite Laval, Quebec City, QC (Canada); Centre de recherche sur le cancer, Universite Laval, Quebec City, QC (Canada); Radiation oncology department, CHU de Quebec, Quebec City, QC (Canada); Center for optics, photonics and lasers, Universite Laval, Quebec City, Quebec (Canada); Goulet, M [Radiation oncology department, CHU de Quebec, Quebec City, QC (Canada); Beaulieu, L; Archambault, L [Department of physics, engineering physics and optics, Universite Laval, Quebec City, QC (Canada); Centre de recherche sur le cancer, Universite Laval, Quebec City, QC (Canada); Radiation oncology department, CHU de Quebec, Quebec City, QC (Canada); Thibault, S [Center for optics, photonics and lasers, Universite Laval, Quebec City, Quebec (Canada)

    2016-06-15

    Purpose: To characterize the performance of a real-time three-dimensional scintillation dosimeter in terms of signal-to-noise ratio (SNR) and temporal resolution of 3D dose measurements. This study quantifies its efficiency in measuring low dose levels characteristic of EBRT dynamic treatments, and in reproducing field profiles for varying multileaf collimator (MLC) speeds. Methods: The dosimeter prototype uses a plenoptic camera to acquire continuous images of the light field emitted by a 10×10×10 cm{sup 3} plastic scintillator. Using EPID acquisitions, ray tracing-based iterative tomographic algorithms allow millimeter-sized reconstruction of relative 3D dose distributions. Measurements were taken at 6MV, 400 MU/min with the scintillator centered at the isocenter, first receiving doses from 1.4 to 30.6 cGy. Dynamic measurements were then performed by closing half of the MLCs at speeds of 0.67 to 2.5 cm/s, at 0° and 90° collimator angles. A reference static half-field was obtained for measured profile comparison. Results: The SNR steadily increases as a function of dose and reaches a clinically adequate plateau of 80 at 10 cGy. Below this, the decrease in light collected and increase in pixel noise diminishes the SNR; nonetheless, the EPID acquisitions and the voxel correlation employed in the reconstruction algorithms result in suitable SNR values (>75) even at low doses. For dynamic measurements at varying MLC speeds, central relative dose profiles are characterized by gradients at %D{sub 50} of 8.48 to 22.7 %/mm. These values converge towards the 32.8 %/mm-gradient measured for the static reference field profile, but are limited by the dosimeter’s current acquisition rate of 1Hz. Conclusion: This study emphasizes the efficiency of the 3D dose distribution reconstructions, while identifying limits of the current prototype’s temporal resolution in terms of dynamic EBRT parameters. This work paves the way for providing an optimized, second

  13. Visualizations of Travel Time Performance Based on Vehicle Reidentification Data

    Energy Technology Data Exchange (ETDEWEB)

    Young, Stanley Ernest [National Renewable Energy Lab, 15013 Denver West Parkway, Golden, CO 80401; Sharifi, Elham [Center for Advanced Transportation Technology, University of Maryland, College Park, Technology Ventures Building, Suite 2200, 5000 College Avenue, College Park, MD 20742; Day, Christopher M. [Joint Transportation Research Program, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47906; Bullock, Darcy M. [Lyles School of Civil Engineering, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47906

    2017-01-01

    This paper provides a visual reference of the breadth of arterial performance phenomena based on travel time measures obtained from reidentification technology that has proliferated in the past 5 years. These graphical performance measures are revealed through overlay charts and statistical distribution as revealed through cumulative frequency diagrams (CFDs). With overlays of vehicle travel times from multiple days, dominant traffic patterns over a 24-h period are reinforced and reveal the traffic behavior induced primarily by the operation of traffic control at signalized intersections. A cumulative distribution function in the statistical literature provides a method for comparing traffic patterns from various time frames or locations in a compact visual format that provides intuitive feedback on arterial performance. The CFD may be accumulated hourly, by peak periods, or by time periods specific to signal timing plans that are in effect. Combined, overlay charts and CFDs provide visual tools with which to assess the quality and consistency of traffic movement for various periods throughout the day efficiently, without sacrificing detail, which is a typical byproduct of numeric-based performance measures. These methods are particularly effective for comparing before-and-after median travel times, as well as changes in interquartile range, to assess travel time reliability.

  14. Photonics-based real-time ultra-high-range-resolution radar with broadband signal generation and processing.

    Science.gov (United States)

    Zhang, Fangzheng; Guo, Qingshui; Pan, Shilong

    2017-10-23

    Real-time and high-resolution target detection is highly desirable in modern radar applications. Electronic techniques have encountered grave difficulties in the development of such radars, which strictly rely on a large instantaneous bandwidth. In this article, a photonics-based real-time high-range-resolution radar is proposed with optical generation and processing of broadband linear frequency modulation (LFM) signals. A broadband LFM signal is generated in the transmitter by photonic frequency quadrupling, and the received echo is de-chirped to a low frequency signal by photonic frequency mixing. The system can operate at a high frequency and a large bandwidth while enabling real-time processing by low-speed analog-to-digital conversion and digital signal processing. A conceptual radar is established. Real-time processing of an 8-GHz LFM signal is achieved with a sampling rate of 500 MSa/s. Accurate distance measurement is implemented with a maximum error of 4 mm within a range of ~3.5 meters. Detection of two targets is demonstrated with a range-resolution as high as 1.875 cm. We believe the proposed radar architecture is a reliable solution to overcome the limitations of current radar on operation bandwidth and processing speed, and it is hopefully to be used in future radars for real-time and high-resolution target detection and imaging.

  15. Coastal CO2 climatology of Oahu, Hawaii: Six years of high resolution time-series data

    Science.gov (United States)

    Terlouw, G. J.; Drupp, P. S.; De Carlo, E. H.; Tomlinson, M.

    2014-12-01

    Six years of high resolution pCO2, water quality, and meteorological data were used to calculate air-sea CO2 fluxes on yearly, seasonal and monthly timescales, and relate the temporal and spatial variation in CO2 fluxes to meteorological events and land derived inputs. Three MAPCO2 buoys are deployed in coastal waters of Oahu as part of the NOAA/PMEL Carbon Program, that autonomously collects CO2 and water quality data at 3-hour intervals. The buoys are located on a backreef in Kaneohe Bay and two fringing reef sites on Oahu's south shore, the latter two in open ocean like conditions but with one also influenced by fluvial inputs. Data for this study were collected from June 2008 to July 2014. Mean pCO2 values at the Ala Wai, Kilo Nalu and CRIMP2 buoys were 396, 381 and 447μatm, respectively, with mean daily ranges of 51, 32 and 190 μatm, respectively. The daily range in pCO2 is largest at CRIMP2, reflecting a combination of higher primary production and respiration, vigorous calcification and longer water residence time within the barrier reef environment. Net annualized air-sea CO2 fluxes of the entire study period were 0.083, -0.014 and 1.167 mol C m-2 year-1 for Ala Wai, Kilo Nalu and CRIMP2, respectively. Positive values indicate a CO2 flux from the water to the atmosphere (source behavior), and negative values from the atmosphere to the water (sink behavior). This presentation will also discuss the effects physical and biogeochemical processes on the magnitude and variability of air-sea CO2 fluxes. We observe a negative correlation between CO2 flux and rainfall over monthly, seasonal, and annual timescales. This correlation however, can partly be explained by temperature, because increased rainfall is more common during the colder winter months. Nevertheless, rainfall affects CO2 fluxes, both by rain-induced nutrient and organic matter runoff, as well as the physical effect of raindrops on air-sea gas exchange and the dilution of the air-sea boundary layer

  16. Time resolution below 100 ps for the SciTil detector of PANDA employing SiPM

    Science.gov (United States)

    Brunner, S. E.; Gruber, L.; Marton, J.; Orth, H.; Suzuki, K.

    2014-03-01

    The barrel time-of-flight (TOF) detector for the bar PANDA experiment at FAIR in Darmstadt is planned as a scintillator tile hodoscope (SciTil) using 8000 small scintillator tiles. It will provide fast event timing for a software trigger in the otherwise trigger-less data acquisition scheme of bar PANDA, relative timing in a multiple track event topology as well as additional particle identification in the low momentum region. The goal is to achieve a time resolution of σ simeq 100 ps. We have conducted measurements using organic scintillators coupled to Silicon Photomultipliers (SiPM). The results are encouraging such that we are confident to reach the required system time resolution.

  17. Retrospective Reconstruction of High Temporal Resolution Cine Images from Real-Time MRI using Iterative Motion Correction

    DEFF Research Database (Denmark)

    Hansen, Michael Schacht; Sørensen, Thomas Sangild; Arai, Andrew

    2012-01-01

    Cardiac function has traditionally been evaluated using breath-hold cine acquisitions. However, there is a great need for free breathing techniques in patients who have difficulty in holding their breath. Real-time cardiac MRI is a valuable alternative to the traditional breath-hold imaging...... approach, but the real-time images are often inferior in spatial and temporal resolution. This article presents a general method for reconstruction of high spatial and temporal resolution cine images from a real-time acquisition acquired over multiple cardiac cycles. The method combines parallel imaging...... and motion correction based on nonrigid registration and can be applied to arbitrary k-space trajectories. The method is demonstrated with real-time Cartesian imaging and Golden Angle radial acquisitions, and the motion-corrected acquisitions are compared with raw real-time images and breath-hold cine...

  18. Verification and Performance Evaluation of Timed Game Strategies

    DEFF Research Database (Denmark)

    David, Alexandre; Fang, Huixing; Larsen, Kim Guldstrand

    2014-01-01

    under the synthesized strategy in order to verify additional correctness properties. Secondly, we want to apply statistical model checking to evaluate various performance aspects of the synthesized strategy. For this, the underlying timed game is extended with relevant price and stochastic information......Control synthesis techniques, based on timed games, derive strategies to ensure a given control objective, e.g., time-bounded reachability. Model checking verifies correctness properties of systems. Statistical model checking can be used to analyse performance aspects of systems, e.g., energy...... consumption. In this work, we propose to combine these three techniques. In particular, given a strategy synthesized for a timed game and a given control objective, we want to make a deeper examination of the consequences of adopting this strategy. Firstly, we want to apply model checking to the timed game...

  19. High resolution time-intensity recording with synchronized solution delivery system for the human dynamic taste perception.

    Science.gov (United States)

    Goto, Tazuko K; Yeung, Andy Wai Kan; Suen, Justin Long Kiu; Fong, Barry Siu Keung; Ninomiya, Yuzo

    2015-04-30

    Time-intensity sensory evaluation of human taste perception is useful to know the feedback of a taste stimulus from tongue. However, it has not been profiled together with reaction time under the constant stimulating tongue in high time resolution. We first made intra-oral device to deliver taste solution to anterior, lateral and posterior tongue in standardized condition. Second, we developed a time-intensity sensory evaluation meter linked to synchronized taste solution delivery system. Time-intensity profiles were recorded in higher temporal resolution than our past study. Third, we analyzed the corrected taste quality reaction time from raw sensory perception data, and following sensory evaluation profile. The new method acquired taste sensory evaluation data with 1 ms temporal resolution and found the reaction timing was 908 ms, the corrected taste quality reaction time was 712 ms, maximum intensity was 3.47, and corrected time to reach maximum intensity was 1312 ms. The coefficient of variation ranged from 0.007 to 0.236 indicating low variance. Time-intensity sensory evaluation in this study did not sacrifice the feature of raw data. The relative comparison of time-intensity sensory profile among subjects will be available in this system in future study, while it was still difficult to define the absolute value of reaction time. Our method could gather real-time feedback for the time-intensity sensory evaluation of a taste stimulus under the standardized stimulating tongue. This could be useful for establishing database of time-intensity sensory profiles for comparison of delicate taste perceptions. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Gas chromatographic quadrupole time-of-flight full scan high resolution mass spectrometric screening of human urine in antidoping analysis

    NARCIS (Netherlands)

    Abushareeda, Wadha; Lyris, Emmanouil; Kraiem, Suhail; Wahaibi, Aisha Al; Alyazidi, Sameera; Dbes, Najib; Lommen, Arjen; Nielen, Michel; Horvatovich, Peter L.; Alsayrafi, Mohammed; Georgakopoulos, Costas

    2017-01-01

    This paper presents the development and validation of a high-resolution full scan (FS) electron impact ionization (EI) gas chromatography coupled to quadrupole Time-of-Flight mass spectrometry (GC/QTOF) platform for screening anabolic androgenic steroids (AAS) in human urine samples. The World

  1. Gas chromatographic quadrupole time-of-flight full scan high resolution mass spectrometric screening of human urine in antidoping analysis

    NARCIS (Netherlands)

    Abushareeda, Wadha; Lyris, Emmanouil; Kraiem, Suhail; Wahaibi, Aisha Al; Alyazidi, Sameera; Dbes, Najib; Lommen, Arjen; Nielen, Michel; Horvatovich, Peter L.; Alsayrafi, Mohammed; Georgakopoulos, Costas

    2017-01-01

    This paper presents the development and validation of a high-resolution full scan (FS) electron impact ionization (EI) gas chromatography coupled to quadrupole Time-of-Flight mass spectrometry (GC/QTOF) platform for screening anabolic androgenic steroids (AAS) in human urine samples. The World

  2. : Signal Decomposition of High Resolution Time Series River data to Separate Local and Regional Components of Conductivity

    Science.gov (United States)

    Signal processing techniques were applied to high-resolution time series data obtained from conductivity loggers placed upstream and downstream of a wastewater treatment facility along a river. Data was collected over 14-60 days, and several seasons. The power spectral densit...

  3. Signal Decomposition of High Resolution Time Series River Data to Separate Local and Regional Components of Conductivity

    Science.gov (United States)

    Signal processing techniques were applied to high-resolution time series data obtained from conductivity loggers placed upstream and downstream of an oil and gas wastewater treatment facility along a river. Data was collected over 14-60 days. The power spectral density was us...

  4. Analysis of the statistical operation of a time-numerical code multistop with a resolution of 0.5ns

    International Nuclear Information System (INIS)

    Festa, E.; Sellem, R.; Tassan-Got, L.

    1983-01-01

    This article describes a multistop TDC with a resolution of 0.5 ns and a dead time less than 40 ns. The broadening of measured distributions is analyzed and calculated for the real device having a discrepancy in channel width and working randomly with sliding scale effect [fr

  5. Development of hard X-ray spectrometer with high time resolution on the J-TEXT tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Ma, T.K.; Chen, Z.Y., E-mail: zychen@hust.edu.cn; Huang, D.W.; Tong, R.H.; Yan, W.; Wang, S.Y.; Dai, A.J.; Wang, X.L.

    2017-06-01

    A hard X-ray (HXR) spectrometer has been developed to study the runaway electrons during the sawtooth activities and during the runaway current plateau phase on the J-TEXT tokamak. The spectrometer system contains four NaI scintillator detectors and a multi-channel analyzer (MCA) with 0.5 ms time resolution. The dedicated peak detection circuit embedded in the MCA provides a pulse height analysis at count rate up to 1.2 million counts per second (Mcps), which is the key to reach the high time resolution. The accuracy and reliability of the system have been verified by comparing with the hardware integrator of HXR flux. The temporal evolution of HXR flux in different energy ranges can be obtained with high time resolution by this dedicated HXR spectrometer. The response of runaway electron transport with different energy during the sawtooth activities can be studied. The energy evolution of runaway electrons during the plateau phase of runaway current can be obtained. - Highlights: • A HXR spectrometer with high time resolution has been developed on J-TEXT tokamak. • The response of REs transport during the sawtooth activities can be investigated. • The energy evolution of REs following the disruptions can be monitored.

  6. Radio frequency phototube and optical clock: High resolution, high rate and highly stable single photon timing technique

    Energy Technology Data Exchange (ETDEWEB)

    Margaryan, Amur

    2011-10-01

    A new timing technique for single photons based on the radio frequency phototube and optical clock or femtosecond optical frequency comb generator is proposed. The technique has a 20 ps resolution for single photons, is capable of operating with MHz frequencies and achieving 10 fs instability level.

  7. Fast collision resolution for real time services in SDMA based wireless ATM networks

    DEFF Research Database (Denmark)

    Vornefeld, U.; Schieimer, D.; Walke, B.

    1999-01-01

    This paper considers random access and collision resolution algorithms in the context of spatial division multiple access (SDMA). We focus on the random access phase of HIPERLAN/2 systems currently under standardization at ETSI-BRAN. Based on the dynamic slot assignment, DSA++ medium access control...... protocol, the influence of SDMA on a contention based access protocol is investigated under collision resolution schemes derived from classical splitting algorithms. Although this work is embedded in the framework of wireless ATM and HIPERLAN/2 systems, the ideas are generally applicable....

  8. Proton Radiography of Laser-Plasma Interactions with Picosecond Time Resolution

    International Nuclear Information System (INIS)

    Mackinnon, A J; Patel, P K; Town, R J; Hatchett, S P; Hicks, D; Phillips, T H; Wilks, S C; Price, D; Key, M H; Lasinski, B; Langdon, B; Borghesi, M; Romagnani, L; Kar, S

    2005-01-01

    Radiography of laser-produced plasmas with MeV protons has the potential to provide new information on plasma conditions in extreme states of matter. Protons with energies up to many hundreds MeV, produced by large scale accelerators have been recently been used to obtain mass density radiographs of the behavior of large samples which have been shocked on microsecond timescales with approximately mm spatial resolution. The recent discovery of laminar proton beams accelerated to multi-MeV energies by picosecond duration laser beams has provided the opportunity to probe dense plasmas with hitherto unparalleled temporal and spatial resolution

  9. A versatile fluorescence lifetime imaging system for scanning large areas with high time and spatial resolution

    Science.gov (United States)

    Bernardo, César; Belsley, Michael; de Matos Gomes, Etelvina; Gonçalves, Hugo; Isakov, Dmitry; Liebold, Falk; Pereira, Eduardo; Pires, Vladimiro; Samantilleke, Anura; Vasilevskiy, Mikhail; Schellenberg, Peter

    2014-08-01

    We present a flexible fluorescence lifetime imaging device which can be employed to scan large sample areas with a spatial resolution adjustable from many micrometers down to sub-micrometers and a temporal resolution of 20 picoseconds. Several different applications of the system will be presented including protein microarrays analysis, the scanning of historical samples, evaluation of solar cell surfaces and nanocrystalline organic crystals embedded in electrospun polymeric nanofibers. Energy transfer processes within semiconductor quantum dot superstructures as well as between dye probes and graphene layers were also investigated.

  10. Non-intrusive, high-resolution, real-time, two-dimensional imaging of multiphase materials using acoustic array sensors

    Energy Technology Data Exchange (ETDEWEB)

    Cassiède, M.; Shaw, J. M. [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2G6 (Canada)

    2015-04-15

    Two parallel multi-element ultrasonic acoustic arrays combined with sets of focal laws for acoustic signal generation and a classical tomographic inversion algorithm are used to generate real-time two-dimensional micro seismic acoustic images of multiphase materials. Proof of concept and calibration measurements were performed for single phase and two phase liquids, uniform polyvinyl chloride (PVC) plates, and aluminum cylinders imbedded in PVC plates. Measurement artefacts, arising from the limited range of viewing angles, and the compromise between data acquisition rate and image quality are discussed. The angle range of scanning and the image resolution were varied, and the effects on the quality of the reproduction of the speed of sound profiles of model solids and liquids with known geometries and compositions were analysed in detail. The best image quality results were obtained for a scanning angle range of [−35°, 35°] at a step size of 2.5° post processed to generate images on a 40 μm square grid. The data acquisition time for high quality images with a 30 mm × 40 mm view field is 10 min. Representation of two-phase solids with large differences in speed of sound between phases and where one phase is dispersed in the form of macroscopic objects (greater than 1 mm in diameter) proved to be the most difficult to image accurately. Liquid-liquid and liquid-vapor phase boundaries, in micro porous solids by contrast, were more readily defined. Displacement of air by water and water by heptane in natural porous limestone provides illustrative kinetic examples. Measurement results with these realistic cases demonstrate the feasibility of the technique to monitor in real time and on the micrometer length scale local composition and flow of organic liquids in inorganic porous media, one of many envisioned engineering applications. Improvement of data acquisition rate is an area for future collaborative study.

  11. Non-intrusive, high-resolution, real-time, two-dimensional imaging of multiphase materials using acoustic array sensors

    Science.gov (United States)

    Cassiède, M.; Shaw, J. M.

    2015-04-01

    Two parallel multi-element ultrasonic acoustic arrays combined with sets of focal laws for acoustic signal generation and a classical tomographic inversion algorithm are used to generate real-time two-dimensional micro seismic acoustic images of multiphase materials. Proof of concept and calibration measurements were performed for single phase and two phase liquids, uniform polyvinyl chloride (PVC) plates, and aluminum cylinders imbedded in PVC plates. Measurement artefacts, arising from the limited range of viewing angles, and the compromise between data acquisition rate and image quality are discussed. The angle range of scanning and the image resolution were varied, and the effects on the quality of the reproduction of the speed of sound profiles of model solids and liquids with known geometries and compositions were analysed in detail. The best image quality results were obtained for a scanning angle range of [-35°, 35°] at a step size of 2.5° post processed to generate images on a 40 μm square grid. The data acquisition time for high quality images with a 30 mm × 40 mm view field is 10 min. Representation of two-phase solids with large differences in speed of sound between phases and where one phase is dispersed in the form of macroscopic objects (greater than 1 mm in diameter) proved to be the most difficult to image accurately. Liquid-liquid and liquid-vapor phase boundaries, in micro porous solids by contrast, were more readily defined. Displacement of air by water and water by heptane in natural porous limestone provides illustrative kinetic examples. Measurement results with these realistic cases demonstrate the feasibility of the technique to monitor in real time and on the micrometer length scale local composition and flow of organic liquids in inorganic porous media, one of many envisioned engineering applications. Improvement of data acquisition rate is an area for future collaborative study.

  12. Modeling time-lagged reciprocal psychological empowerment-performance relationships.

    Science.gov (United States)

    Maynard, M Travis; Luciano, Margaret M; D'Innocenzo, Lauren; Mathieu, John E; Dean, Matthew D

    2014-11-01

    Employee psychological empowerment is widely accepted as a means for organizations to compete in increasingly dynamic environments. Previous empirical research and meta-analyses have demonstrated that employee psychological empowerment is positively related to several attitudinal and behavioral outcomes including job performance. While this research positions psychological empowerment as an antecedent influencing such outcomes, a close examination of the literature reveals that this relationship is primarily based on cross-sectional research. Notably, evidence supporting the presumed benefits of empowerment has failed to account for potential reciprocal relationships and endogeneity effects. Accordingly, using a multiwave, time-lagged design, we model reciprocal relationships between psychological empowerment and job performance using a sample of 441 nurses from 5 hospitals. Incorporating temporal effects in a staggered research design and using structural equation modeling techniques, our findings provide support for the conventional positive correlation between empowerment and subsequent performance. Moreover, accounting for the temporal stability of variables over time, we found support for empowerment levels as positive influences on subsequent changes in performance. Finally, we also found support for the reciprocal relationship, as performance levels were shown to relate positively to changes in empowerment over time. Theoretical and practical implications of the reciprocal psychological empowerment-performance relationships are discussed. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  13. Resolution tests of global geodynamic models by travel-time tomography

    Czech Academy of Sciences Publication Activity Database

    Běhounková, Marie; Čížková, H.; Matyska, C.

    2005-01-01

    Roč. 49, č. 3 (2005), s. 343-363 ISSN 0039-3169 R&D Projects: GA ČR GA205/02/1306 Institutional research plan: CEZ:AV0Z30120515 Keywords : seismic tomography * synthetic inversion * resolution tests Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.656, year: 2005

  14. Explorative analysis of long time series of very high resolution spatial rainfall

    DEFF Research Database (Denmark)

    Thomassen, Emma Dybro; Sørup, Hjalte Jomo Danielsen; Scheibel, Marc

    2017-01-01

    We examine rainfall characteristics of convective and front extreme events in high spatio-temporal resolution (5 minutes, 1x1 km) over an area of 1824 km2 covering the catchment of the Wupperverband, North Rhine-Westphalia. The main focus of the analysis is a description of the complexity of hour...

  15. Agricultural Recharge Practices for Managing Nitrate in Regional Groundwater: Time-Resolution Assessment of Numerical Modeling Approach

    Science.gov (United States)

    Bastani, M.; Harter, T.

    2017-12-01

    Intentional recharge practices in irrigated landscapes are promising options to control and remediate groundwater quality degradation with respect to nitrate. To better understand the effect of these practices, a fully 3D transient heterogeneous transport model simulation is developed using MODFLOW and MT3D. The model is developed for a long-term study of nitrate improvements in an alluvial groundwater basin in Eastern San Joaquin Valley, CA. Different scenarios of agricultural recharge strategies including crop type change and winter flood flows are investigated. Transient simulations with high spatio-temporal resolutions are performed. We then consider upscaling strategies that would allow us to simplify the modeling process such that it can be applied at a very large basin-scale (1000s of square kilometers) for scenario analysis. We specifically consider upscaling of time-variant boundary conditions (both internal and external) that have significant influence on calculation cost of the model. We compare monthly transient stresses to upscaled annual and further upscaled average steady-state stresses on nitrate transport in groundwater under recharge scenarios.

  16. Position and time resolution measurements with a microchannel plate image intensifier: A comparison of monolithic and pixelated CeBr{sub 3} scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, Ulrich, E-mail: ulrich.ackermann@unibw.de [Universität der Bundeswehr München, Institut für angewandte Physik und Messtechnik (LRT2), Werner-Heisenberg-Weg 39, 85577 Neubiberg (Germany); Eschbaumer, Stephan, E-mail: stephan.eschbaumer@unibw.de [Universität der Bundeswehr München, Institut für angewandte Physik und Messtechnik (LRT2), Werner-Heisenberg-Weg 39, 85577 Neubiberg (Germany); Bergmaier, Andreas, E-mail: andreas.bergmaier@unibw.de [Universität der Bundeswehr München, Institut für angewandte Physik und Messtechnik (LRT2), Werner-Heisenberg-Weg 39, 85577 Neubiberg (Germany); Egger, Werner, E-mail: werner.egger@unibw.de [Universität der Bundeswehr München, Institut für angewandte Physik und Messtechnik (LRT2), Werner-Heisenberg-Weg 39, 85577 Neubiberg (Germany); Sperr, Peter, E-mail: peter.sperr@unibw.de [Universität der Bundeswehr München, Institut für angewandte Physik und Messtechnik (LRT2), Werner-Heisenberg-Weg 39, 85577 Neubiberg (Germany); Greubel, Christoph, E-mail: christoph.greubel@unibw.de [Universität der Bundeswehr München, Institut für angewandte Physik und Messtechnik (LRT2), Werner-Heisenberg-Weg 39, 85577 Neubiberg (Germany); and others

    2016-07-01

    To perform Four Dimensional Age Momentum Correlation measurements in the near future, where one obtains the positron lifetime in coincidence with the three dimensional momentum of the electron annihilating with the positron, we have investigated the time and position resolution of two CeBr{sub 3} scintillators (monolithic and an array of pixels) using a Photek IPD340/Q/BI/RS microchannel plate image intensifier. The microchannel plate image intensifier has an active diameter of 40 mm and a stack of two microchannel plates in chevron configuration. The monolithic CeBr{sub 3} scintillator was cylindrically shaped with a diameter of 40 mm and a height of 5 mm. The pixelated scintillator array covered the whole active area of the microchannel plate image intensifier and the shape of each pixel was 2.5·2.5·8 mm{sup 3} with a pixel pitch of 3.3 mm. For the monolithic setup the measured mean single time resolution was 330 ps (FWHM) at a gamma energy of 511 keV. No significant dependence on the position was detected. The position resolution at the center of the monolithic scintillator was about 2.5 mm (FWHM) at a gamma energy of 662 keV. The single time resolution of the pixelated crystal setup reached 320 ps (FWHM) in the region of the center of the active area of the microchannel plate image intensifier. The position resolution was limited by the cross-section of the pixels. The gamma energy for the pixel setup measurements was 511 keV.

  17. Quality of E-Learners’ Time and Learning Performance Beyond Quantitative Time-on-Task

    Directory of Open Access Journals (Sweden)

    Margarida Romero

    2011-06-01

    Full Text Available AbstractAlong with the amount of time spent learning (or time-on-task, the quality of learning time has a real influence on learning performance. Quality of time in online learning depends on students’ time availability and their willingness to devote quality cognitive time to learning activities. However, the quantity and quality of the time spent by adult e-learners on learning activities can be reduced by professional, family, and social commitments. Considering that the main time pattern followed by most adult e-learners is a professional one, it may be beneficial for online education programs to offer a certain degree of flexibility in instructional time that might allow adult learners to adjust their learning times to their professional constraints. However, using the time left over once professional and family requirements have been fulfilled could lead to a reduction in quality time for learning. This paper starts by introducing the concept of quality of learning time from an online student-centred perspective. The impact of students’ time-related variables (working hours, time-on-task engagement, time flexibility, time of day, day of week is then analyzed according to individual and collaborative grades achieved during an online master’s degree program. The data show that both students’ time flexibility (r = .98 and especially their availability to learn in the morning are related to better grades in individual (r = .93 and collaborative activities (r = .46.

  18. Comparing targeted and non-targeted high-resolution mass spectrometric approaches for assessing advanced oxidation reactor performance.

    Science.gov (United States)

    Parry, Emily; Young, Thomas M

    2016-11-01

    High resolution mass spectrometry (HR-MS) offers the opportunity to track large numbers of non-target analytes through water treatment processes, providing a more comprehensive view of reactor performance than targeted evaluation. Both approaches were used to evaluate the performance of a pilot scale advanced oxidation process (AOP) employing ultraviolet light and hydrogen peroxide (UV/H 2 O 2 ) to treat municipal wastewater effluent. Twelve pharmaceuticals and personal care products were selected as target compounds and added to reactor influent. Target compound removal over a range of flow rates and hydrogen peroxide addition levels was assessed using a liquid chromatograph combined with a quadrupole time-of-flight mass spectrometer (LC-qTOF-MS). Target compound removals were used to determine hydroxyl radical concentrations and UV fluence under pilot scale conditions. The experiments were also analyzed using a nontarget approach, which identified "molecular features" in either reactor influent or effluent. Strong correlation (r = 0.94) was observed between target compound removals calculated using the targeted and non-targeted approaches across the range of reactor conditions tested. The two approaches also produced consistent rankings of the performance of the various reactor operating conditions, although the distribution of compound removal efficiencies was usually less favorable with the broader, nontarget approach. For example, in the UV only treatment 8.3% of target compounds and 2.2% of non-target compounds exhibited removals above 50%, while 100% of target compounds and 74% of non-target compounds exhibited removals above 50% in the best condition tested. These results suggest that HR-MS methods can provide more holistic evaluation of reactor performance, and may reduce biases caused by selection of a limited number of target compounds. HR-MS methods also offer insights into the composition of poorly removed compounds and the formation of

  19. Understanding the Performance of Automotive Catalysts via Spatial Resolution of Reactions inside Honeycomb Monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Partridge Jr, William P. [ORNL; Choi, Jae-Soon [ORNL

    2017-11-01

    By directly resolving spatial and temporal species distributions within operating honeycomb monolith catalysts, spatially resolved capillary inlet mass spectrometry (SpaciMS) provides a uniquely enabling perspective for advancing automotive catalysis. Specifically, the ability to follow the spatiotemporal evolution of reactions throughout the catalyst is a significant advantage over inlet-and-effluent-limited analysis. Intracatalyst resolution elucidates numerous catalyst details including the network and sequence of reactions, clarifying reaction pathways; the relative rates of different reactions and impacts of operating conditions and catalyst state; and reaction dynamics and intermediate species that exist only within the catalyst. These details provide a better understanding of how the catalyst functions and have basic and practical benefits; e.g., catalyst system design; strategies for on-road catalyst state assessment, control, and on-board diagnostics; and creating robust and accurate predictive catalyst models. Moreover, such spatiotemporally distributed data provide for critical model assessment, and identification of improvement opportunities that might not be apparent from effluent assessment; i.e., while an incorrectly formulated model may provide correct effluent predictions, one that can accurately predict the spatiotemporal evolution of reactions along the catalyst channels will be more robust, accurate, and reliable. In such ways, intracatalyst diagnostics comprehensively enable improved design and development tools, and faster and lower-cost development of more efficient and durable automotive catalyst systems. Beyond these direct contributions, SpaciMS has spawned and been applied to enable other analytical techniques for resolving transient distributed intracatalyst performance. This chapter focuses on SpaciMS applications and associated catalyst insights and improvements, with specific sections related to lean NOx traps, selective catalytic

  20. Analysis of high resolution scatter images from laser damage experiments performed on KDP

    International Nuclear Information System (INIS)

    Runkel, M.; Woods, B.; Yan, M.

    1996-01-01

    Interest in producing high damage threshold KH 2 PO 4 (KDP) and (D x H 1-x ) 2 PO 4 (KD*P, DKDP) for optical switching and frequency conversion applications is being driven by the system requirements for the National Ignition Facility (NIF) at Lawrence Livermore National Lab (LLNL). Historically, the path to achieving higher damage thresholds has been to improve the purity of crystal growth solutions. Application of advanced filtration technology has increased the damage threshold, but gives little insight into the actual mechanisms of laser damage. We have developed a laser scatter diagnostic to better study bulk defects and laser damage mechanisms in KDP and KD*P crystals. This diagnostic consists of a cavity doubled, kilohertz class, Nd:YLF laser (527 nm) and high dynamic range CCD camera which allows imaging of bulk scatter signals. With it, we have performed damage tests at 355 nm on four different open-quotes vintagesclose quotes of KDP crystals, concentrating on crystals produced via fast growth methods. We compare the diagnostic's resolution to LLNL's standard damage detection method of 100X darkfield microscopy and discuss its impact on damage threshold determination. We have observed the disappearance of scatter sites upon exposure to subthreshold irradiation. In contrast, we have seen scatterers appear where none previously existed. This includes isolated, large (high signal) sites as well as multiple small scatter sites which appear at fluences above 7 J/cm 2 (fine tracking). However, we have not observed a strong correlation of preexisting scatter sites and laser damage sites. We speculate on the connection between the laser-induced disappearance of scatter sites and the observed increase in damage threshold with laser conditioning

  1. Open design eight-channel transmit/receive coil for high-resolution and real-time ankle imaging at 7 T.

    Science.gov (United States)

    Orzada, Stephan; Bitz, Andreas K; Schäfer, Lena C; Ladd, Susanne C; Ladd, Mark E; Maderwald, Stefan

    2011-03-01

    At 1.5 T, real-time MRI of joint movement has been shown to be feasible. However, 7 T, provides higher SNR and thus an improved potential for parallel imaging acceleration. The purpose of this work was to build an open, U-shaped eight-channel transmit/receive microstrip coil for 7 T MRI to enable high-resolution and real-time imaging of the moving ankle joint. A U-shaped eight-channel transmit/receive array for the human ankle was built. S-parameters and g-factor were measured. SAR calculations of different ankle postures were performed to ensure patient safety. Inhomogeneities in the transmit field consequent to the open design were compensated for by the use of static RF shimming. High-resolution and real-time imaging was performed in human volunteers. The presented array showed good performance with regard to patient comfort and image quality. High acceleration factors of up to 4 are feasible without visible acceleration artifacts. Reasonable image homogeneity was achieved with RF shimming. Open, noncylindrical designs for transmit/receive coils are practical at 7 T and real-time imaging of the moving joint is feasible with the presented coil design.

  2. arXiv Photon detector system performance in the DUNE 35-ton prototype liquid argon time projection chamber

    CERN Document Server

    Adams, D.L.; Anderson, J.T.; Bagby, L.; Baird, M.; Barr, G.; Barros, N.; Biery, K.; Blake, A.; Blaufuss, E.; Boone, T.; Booth, A.; Brailsford, D.; Buchanan, N.; Chatterjee, A.; Convery, M.; Davies, J.; Dealtry, T.; DeLurgio, P.; Deuerling, G.; Dharmapalan, R.; Djurcic, Z.; Drake, G.; Eberly, B.; Freeman, J.; Glavin, S.; Gomes, R.A.; Goodman, M.C.; Graham, M.; Hahn, A.; Haigh, J.T.; Hartnell, J.; Higuera, A.; Himmel, A.; Insler, J.; Jacobsen, J.; Junk, T.; Kirby, B.; Klein, J.; Kudryavtsev, V.A.; Kutter, T.; Li, Y.; Li, X.; Lin, S.; Martin-Albo, J.; McConkey, N.; Moura, C.A.; Mufson, S.; Nicholls, T.C.; Nowak, J.; Oberling, M.; Paley, J.; Qian, X.; Raaf, J.L.; Rivera, D.; Santucci, G.; Sinev, G.; Spooner, N.J. C.; Stancari, M.; Stancu, I.; Stefan, D.; Stewart, J.; Stock, J.; Strauss, T.; Sulej, R.; Sun, Y.; Thiesse, M.; Thompson, L.F.; Tsai, Y.T.; Wallbank, M.; Warburton, T.K.; Warner, D.; Whittington, D.; Wilson, R.J.; Worcester, M.; Worcester, E.; Yang, T.; Zhang, C.

    The 35-ton prototype for the Deep Underground Neutrino Experiment far detector was a single-phase liquid argon time projection chamber with an integrated photon detector system, all situated inside a membrane cryostat. The detector took cosmic-ray data for six weeks during the period of February 1, 2016 to March 12, 2016. The performance of the photon detection system was checked with these data. An installed photon detector was demonstrated to measure the arrival times of cosmic-ray muons with a resolution better than 32 ns, limited by the timing of the trigger system. A measurement of the timing resolution using closely-spaced calibration pulses yielded a resolution of 15 ns for pulses at a level of 6 photo-electrons. Scintillation light from cosmic-ray muons was observed to be attenuated with increasing distance with a characteristic length of $155 \\pm 28$ cm.

  3. Performance Evaluation of Real-Time Precise Point Positioning Method

    Science.gov (United States)

    Alcay, Salih; Turgut, Muzeyyen

    2017-12-01

    Post-Processed Precise Point Positioning (PPP) is a well-known zero-difference positioning method which provides accurate and precise results. After the experimental tests, IGS Real Time Service (RTS) officially provided real time orbit and clock products for the GNSS community that allows real-time (RT) PPP applications. Different software packages can be used for RT-PPP. In this study, in order to evaluate the performance of RT-PPP, 3 IGS stations are used. Results, obtained by using BKG Ntrip Client (BNC) Software v2.12, are examined in terms of both accuracy and precision.

  4. Does expressive timing in music performance scale proportionally with tempo?

    NARCIS (Netherlands)

    Desain, P.; Honing, H.

    1994-01-01

    Evidence is presented that expressive timing in music is not relationally invariant with global tempo. Our results stem from an analysis of repeated performances of Beethoven's variations on a Paisiello theme. Recordings were made of two pianists playing the pieces at three tempi. In contrast with

  5. Timing the arrival at 2340m altitude for aerobic performance

    DEFF Research Database (Denmark)

    Schuler, B; Thomsen, JJ; Gassmann, M

    2007-01-01

    samples were taken on these days before performing two consecutive maximal exercise trials. Acclimatization reased hemoglobin concentration and arterial oxygen content. On Day 1, VO2max and time to exhaustion (at 80% of sea-level maximal power output) decreased by 12.8% (P

  6. Timing performances of a data acquisition system for Time of Flight PET

    International Nuclear Information System (INIS)

    Morrocchi, Matteo; Marcatili, Sara; Belcari, Nicola; Bisogni, Maria G.; Collazuol, Gianmaria; Ambrosi, Giovanni; Corsi, Francesco; Foresta, Maurizio; Marzocca, Cristoforo; Matarrese, Gianvito; Sportelli, Giancarlo; Guerra, Pedro; Santos, Andres; Del Guerra, Alberto

    2012-01-01

    We are investigating the performances of a data acquisition system for Time of Flight PET, based on LYSO crystal slabs and 64 channels Silicon Photomultipliers matrices (1.2 cm 2 of active area each). Measurements have been performed to test the timing capability of the detection system (SiPM matices coupled to a LYSO slab and the read-out electronics) with both test signal and radioactive source.

  7. Timing performances of a data acquisition system for Time of Flight PET

    Energy Technology Data Exchange (ETDEWEB)

    Morrocchi, Matteo, E-mail: matteo.morrocchi@pi.infn.it [University of Pisa and INFN Sezione di Pisa, I 56127 Pisa (Italy); Marcatili, Sara; Belcari, Nicola; Bisogni, Maria G. [University of Pisa and INFN Sezione di Pisa, I 56127 Pisa (Italy); Collazuol, Gianmaria [University of Padova and INFN Sezione di Padova (Italy); Ambrosi, Giovanni [INFN Sezione di Perugia, I 06100 Perugia (Italy); Corsi, Francesco; Foresta, Maurizio; Marzocca, Cristoforo; Matarrese, Gianvito [Politecnico di Bari and INFN Sezione di Bari, I 70100 Bari (Italy); Sportelli, Giancarlo; Guerra, Pedro; Santos, Andres [Universidad Politecnica de Madrid, E 28040 Madrid (Spain); Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Del Guerra, Alberto [University of Pisa and INFN Sezione di Pisa, I 56127 Pisa (Italy)

    2012-12-11

    We are investigating the performances of a data acquisition system for Time of Flight PET, based on LYSO crystal slabs and 64 channels Silicon Photomultipliers matrices (1.2 cm{sup 2} of active area each). Measurements have been performed to test the timing capability of the detection system (SiPM matices coupled to a LYSO slab and the read-out electronics) with both test signal and radioactive source.

  8. Improved Count Rate and Resolution Performance of a Thermoelectrically Cooled Si(Li) X-ray Detector.

    Science.gov (United States)

    Barkan; Ihrig; Abott

    1999-03-01

    : A new energy-dispersive spectrometer Si(Li) detector for microanalysis applications, cooled by a thermoelectric (Peltier) refrigerator, was significantly improved with regard to the resolution and high count-rate performance. This new detector was mounted on a JEOL 6400 scanning electron microscope, and several application tests were run to analyze its performance. The common resolution test using an Fe55 radioactive source was performed, and it was compared with the conventional liquid nitrogen (LN) detector. The resolution at low and high count-rate was found to be slightly less than the LN detector's performance; however, these differences are minor and most application requirements were easily met. The thermoelectric cooling mechanism was found to be stable and reliable with no degradation in its performance recorded during several years of use. The collected data show improved performance by the new thermoelectrically cooled (TEC) detector compared with the old TEC design and underscore performance very close to the LN product. For most microanalysis applications, the new TEC X-ray detector can easily replace the LN detector and avoid the maintenance associated with LN filling.

  9. Freight Transport Time Savings and Organizational Performance: A Systemic Approach

    Directory of Open Access Journals (Sweden)

    Evangelos Sambracos

    2013-04-01

    Full Text Available This paper investigates the effect of freight transport time savings (FTTS on the performance of transport consuming companies. In the first part existing methods on FTTS valuation are critically discussed and their limitations are identified. Following, a conceptual model is built introducing an alternative approach for the valuation of FTTS that is based on the system perspective of firms, integrating the disciplines of systems thinking, performance measurement, transport and logistics decision making. Evidence from a Systems Dynamics’ simulation experiment on a retailer suggests that the effect of FTTS on performance depends highly on the structure of the firm's transport related processes and decision making process. Through the development and simulation of several scenarios concerning the reaction of the firm to the FTTS, it is concluded that the value of FTTS is sensitive to the type of the reaction and its time profile.

  10. Danish Mutual Fund Performance - Selectivity, Market Timing and Persistence

    DEFF Research Database (Denmark)

    Christensen, Michael

    Funds under management by Danish mutual funds have increased by 25% annually during the last 10 years and measured per capita Denmark has the third largest mutual fund industry in Europe. This paper provides the first independent performance analysis of Danish mutual funds. We analyse selectivity...... applying a single index model and a multi-factor model, respectively. Furthermore, we analyse the timing ability of the Danish mutual funds pursuing both the quadratic regressions of Treynor and Mazuy (1966) and the option approach suggested by Henriksson and Merton (1981). Finally, we analyse performance...... persistence using parametric as well as non-parametric methodologies. We conclude that in general Danish mutual funds perform neutrally, returns are non-persistent and Danish mutual funds have no timing ability....

  11. The effect of extrinsic motivation on cycle time trial performance.

    Science.gov (United States)

    Hulleman, Michiel; De Koning, Jos J; Hettinga, Florentina J; Foster, Carl

    2007-04-01

    Athletes occasionally follow pacing patterns that seem unreasonably aggressive compared with those of prerace performances, potentially because of the motivation provided by competition. This study evaluated the effect of extrinsic motivation on cyclists' time trial performance. Well-trained recreational cyclists (N=7) completed four 1500-m laboratory time trials including a practice trial, two self-paced trials, and a trial where a monetary reward was offered. Time, total power output, power output attributable to aerobic and anaerobic metabolic sources, VO2, and HR were measured. The time required for the second, third, and last (extrinsically motivated) time trials was 133.1 +/- 2.1, 134.1 +/- 3.4, and 133.6 +/- 3.0 s, respectively, and was not different (P>0.05). There were no differences for total (396 +/- 19, 397 +/- 23, and 401 +/- 17 W), aerobic (253 +/- 12, 254 +/- 10, and 246 +/- 13 W), and anaerobic (143 +/- 14, 143 +/- 21, and 155 +/- 11 W) power output. The highest VO2 was not different over consecutive time trials (3.76 +/- 0.19, 3.73 +/- 0.16, and 3.71 +/- 0.22 L x min(-1)). When ranked by performance, without reference to the extrinsic motivation (131.9 +/- 2.4, 133.4 +/- 2.4, and 135.4 +/- 2.5 s), there was a significant difference for the first 100 m and from 100 to 300 m in power output, with a larger total power (560 +/- 102, 491 +/- 82, and 493 +/- 93; and 571 +/- 94, 513 +/- 41, and 484 +/- 88 W) and power attributable to anaerobic sources (446 +/- 100, 384 +/- 80, and 324 +/- 43; and 381 +/- 87, 383 +/- 90, and 289 +/- 91 W) for the fastest trial. Extrinsic motivation did not change the time trial performance, suggesting that 1500-m performance is extremely stable and not readily changeable with simple external motivation. The results suggest that spontaneous improvement in performance for time trials of this duration is attributable to greater early power output, which is primarily attributable to anaerobic metabolic sources.

  12. Estimate of Passive Time Reversal Communication Performance in Shallow Water

    Directory of Open Access Journals (Sweden)

    Sunhyo Kim

    2017-12-01

    Full Text Available Time reversal processes have been used to improve communication performance in the severe underwater communication environment characterized by significant multipath channels by reducing inter-symbol interference and increasing signal-to-noise ratio. In general, the performance of the time reversal is strongly related to the behavior of the q -function, which is estimated by a sum of the autocorrelation of the channel impulse response for each channel in the receiver array. The q -function depends on the complexity of the communication channel, the number of channel elements and their spacing. A q -function with a high side-lobe level and a main-lobe width wider than the symbol duration creates a residual ISI (inter-symbol interference, which makes communication difficult even after time reversal is applied. In this paper, we propose a new parameter, E q , to describe the performance of time reversal communication. E q is an estimate of how much of the q -function lies within one symbol duration. The values of E q were estimated using communication data acquired at two different sites: one in which the sound speed ratio of sediment to water was less than unity and one where the ratio was higher than unity. Finally, the parameter E q was compared to the bit error rate and the output signal-to-noise ratio obtained after the time reversal operation. The results show that these parameters are strongly correlated to the parameter E q .

  13. Flexibility of Expressive Timing in Repeated Musical Performances.

    Science.gov (United States)

    Demos, Alexander P; Lisboa, Tânia; Chaffin, Roger

    2016-01-01

    Performances by soloists in the Western classical tradition are normally highly prepared, yet must sound fresh and spontaneous. How do musicians manage this? We tested the hypothesis that they achieve the necessary spontaneity by varying the musical gestures that express their interpretation of a piece. We examined the tempo arches produced by final slowing at the ends of phrases in performances of J. S. Bach's No. 6 (Prelude) for solo cello (12 performances) and the Italian Concerto (Presto) for solo piano (eight performances). The performances were given by two experienced concert soloists during a short time period (3½ months for the Prelude, 2 weeks for the Presto) after completing their preparations for public performance. We measured the tempo of each bar or half-bar, and the stability of tempo across performances (difference of the tempo of each bar/half bar from each of the other performances). There were phrase arches for both tempo and stability with slower, less stable tempi at beginnings and ends of phrases and faster, more stable tempi mid-phrase. The effects of practice were complex. Tempo decreased overall with practice, while stability increased in some bars and decreased in others. One effect of practice may be to imbue well-learned, automatic motor sequences with freshness and spontaneity through cognitive control at phrase boundaries where slower tempi and decreased stability provide opportunities for slower cognitive processes to modulate rapid automatic motor sequences.

  14. Flexibility of Expressive Timing in Repeated Musical Performances

    Directory of Open Access Journals (Sweden)

    Alexander Pantelis Demos

    2016-10-01

    Full Text Available Performances by soloists in the Western classical tradition are normally highly prepared, yet must sound fresh and spontaneous. How do musicians manage this? We tested the hypothesis that they achieve the necessary spontaneity by varying the musical gestures that express their interpretation of a piece. We examined the tempo arches produced by final slowing at the ends of phrases in performances of J.S. Bach’s No. 6 (Prelude for solo cello (12 performances and the Italian Concerto (Presto for solo piano (8 performances. The performances were given by two experienced concert soloists during a short time period (3½ months for the Prelude, 2 weeks for the Presto after completing their preparations for public performance. We measured the tempo of each bar or half-bar, and the stability of tempo across performances (difference of the tempo of each bar/half bar from each of the other performances. There were phrase arches for both tempo and stability with slower, less stable tempi at beginnings and ends of phrases and faster, more stable tempi mid-phrase. The effects of practice were complex. Tempo decreased overall with practice, while stability increased in some bars and decreased in others. One effect of practice may be to imbue well-learned, automatic motor sequences with freshness and spontaneity through cognitive control at phrase boundaries where slower tempi and decreased stability provide opportunities for slower cognitive processes to modulate rapid automatic motor sequences.

  15. A Systematic Study to Optimize SiPM Photo-Detectors for Highest Time Resolution in PET

    CERN Document Server

    Gundacker, S.; Frisch, B.; Hillemanns, H.; Jarron, P.; Meyer, T.; Pauwels, K.; Lecoq, P.

    2012-01-01

    We report on a systematic study of time resolution made with three different commercial silicon photomultipliers (SiPMs) (Hamamatsu MPPC S10931-025P, S10931-050P, and S10931-100P) and two LSO scintillating crystals. This study aimed to determine the optimum detector conditions for highest time resolution in a prospective time-of-flight positron emission tomography (TOF-PET) system. Measurements were based on the time over threshold method in a coincidence setup using the ultrafast amplifier-discriminator NINO and a fast oscilloscope. Our tests with the three SiPMs of the same area but of different SPAD sizes and fill factors led to best results with the Hamamatsu type of 50×50×μm2 single-pixel size. For this type of SiPM and under realistic geometrical PET scanner conditions, i.e., with 2×2×10×mm3 LSO crystals, a coincidence time resolution of 220 ±4 ps FWHM could be achieved. The results are interpreted in terms of SiPM photon detection efficiency (PDE), dark noise, and photon yield.

  16. Development of an integrated four-channel fast avalanche-photodiode detector system with nanosecond time resolution

    Science.gov (United States)

    Li, Zhenjie; Li, Qiuju; Chang, Jinfan; Ma, Yichao; Liu, Peng; Wang, Zheng; Hu, Michael Y.; Zhao, Jiyong; Alp, E. E.; Xu, Wei; Tao, Ye; Wu, Chaoqun; Zhou, Yangfan

    2017-10-01

    A four-channel nanosecond time-resolved avalanche-photodiode (APD) detector system is developed at Beijing Synchrotron Radiation. It uses a single module for signal processing and readout. This integrated system provides better reliability and flexibility for custom improvement. The detector system consists of three parts: (i) four APD sensors, (ii) four fast preamplifiers and (iii) a time-digital-converter (TDC) readout electronics. The C30703FH silicon APD chips fabricated by Excelitas are used as the sensors of the detectors. It has an effective light-sensitive area of 10 × 10 mm2 and an absorption layer thickness of 110 μm. A fast preamplifier with a gain of 59 dB and bandwidth of 2 GHz is designed to readout of the weak signal from the C30703FH APD. The TDC is realized by a Spartan-6 field-programmable-gate-array (FPGA) with multiphase method in a resolution of 1ns. The arrival time of all scattering events between two start triggers can be recorded by the TDC. The detector has been used for nuclear resonant scattering study at both Advanced Photon Source and also at Beijing Synchrotron Radiation Facility. For the X-ray energy of 14.4 keV, the time resolution, the full width of half maximum (FWHM) of the detector (APD sensor + fast amplifier) is 0.86 ns, and the whole detector system (APD sensors + fast amplifiers + TDC readout electronics) achieves a time resolution of 1.4 ns.

  17. Real-time individualization of the unified model of performance.

    Science.gov (United States)

    Liu, Jianbo; Ramakrishnan, Sridhar; Laxminarayan, Srinivas; Balkin, Thomas J; Reifman, Jaques

    2017-12-01

    Existing mathematical models for predicting neurobehavioural performance are not suited for mobile computing platforms because they cannot adapt model parameters automatically in real time to reflect individual differences in the effects of sleep loss. We used an extended Kalman filter to develop a computationally efficient algorithm that continually adapts the parameters of the recently developed Unified Model of Performance (UMP) to an individual. The algorithm accomplishes this in real time as new performance data for the individual become available. We assessed the algorithm's performance by simulating real-time model individualization for 18 subjects subjected to 64 h of total sleep deprivation (TSD) and 7 days of chronic sleep restriction (CSR) with 3 h of time in bed per night, using psychomotor vigilance task (PVT) data collected every 2 h during wakefulness. This UMP individualization process produced parameter estimates that progressively approached the solution produced by a post-hoc fitting of model parameters using all data. The minimum number of PVT measurements needed to individualize the model parameters depended upon the type of sleep-loss challenge, with ~30 required for TSD and ~70 for CSR. However, model individualization depended upon the overall duration of data collection, yielding increasingly accurate model parameters with greater number of days. Interestingly, reducing the PVT sampling frequency by a factor of two did not notably hamper model individualization. The proposed algorithm facilitates real-time learning of an individual's trait-like responses to sleep loss and enables the development of individualized performance prediction models for use in a mobile computing platform. © 2017 European Sleep Research Society.

  18. Relationships between Isometric Force-Time Characteristics and Dynamic Performance

    Directory of Open Access Journals (Sweden)

    Thomas Dos’Santos

    2017-09-01

    Full Text Available The purpose of this study was to explore the relationships between isometric mid-thigh pull (IMTP force-time characteristics (peak force and time-specific force vales (100–250 ms and dynamic performance and compare dynamic performance between stronger and weaker athletes. Forty-three athletes from different sports (rowing, soccer, bicycle motocross, and hockey performed three trials of the squat jump (SJ, countermovement jump (CMJ, and IMTP, and performed a one repetition maximum power clean (PC. Reactive strength index modified (RSImod was also calculated from the CMJ. Statistically significant large correlations between IMTP force-time characteristics and PC (ρ = 0.569–0.674, p < 0.001, and moderate correlations between IMTP force-time characteristics (excluding force at 100 ms and RSImod (ρ = 0.389–0.449, p = 0.013–0.050 were observed. Only force at 250 ms demonstrated a statistically significant moderate correlation with CMJ height (ρ = 0.346, p = 0.016 and no statistically significant associations were observed between IMTP force-time characteristics and SJ height. Stronger athletes (top 10 demonstrated statistically significantly greater CMJ heights, RSImods, and PCs (p ≤ 0.004, g = 1.32–1.89 compared to weaker (bottom 10 athletes, but no differences in SJ height were observed (p = 0.871, g = 0.06. These findings highlight that the ability to apply rapidly high levels of force in short time intervals is integral for PC, CMJ height, and reactive strength.

  19. Direct determination of acrylamide in food by gas chromatography-high-resolution time-of-flight mass spectrometry

    International Nuclear Information System (INIS)

    Dunovska, Lenka; Cajka, Tomas; Hajslova, Jana; Holadova, Katerina

    2006-01-01

    Simple and rapid gas chromatographic (GC) method employing a high-resolution time-of-flight mass analyzer that enables direct analysis (no derivatization) of acrylamide in various heat-processed foodstuffs has been developed and validated. Co-isolation of acrylamide precursors such as sugars and asparagine, constituting the risk of results overestimation due to additional formation of analyte in hot GC injector, is avoided by the extraction with n-propanol followed by solvent exchange to acetonitrile (MeCN). Introduction of a novel purification strategy, dispersive solid phase extraction, based on addition of primary-secondary amine (PSA) sorbent into deffated extract in MeCN, provides a significant reduction of some abundant matrix co-extracts (mainly free fatty acids). Isotope dilution technique (d 3 -acrylamide as an internal standard) is employed for compensation of potential target analyte losses and/or matrix-inducted chromatographic response enhancement. Limits of quantifications (LOQs) ranged between 15 and 40 μg kg -1 and recoveries were between 97 and 108% depending on the examined food matrix. The repeatability of measurements (expressed as relative standard deviation, R.S.D.) was as low as 1.9% for potato crisps containing acrylamide at a level of 1 mg kg -1 . Slightly higher values (R.S.D. < 4.0%) were achieved for breakfast cereals and crisp bread with approximately 10 times lower content of this processing contaminant. Trueness of results generated by this new method was demonstrated via FAPAS[reg] (Food Analysis Performance Assessment Scheme) interlaboratory proficiency tests

  20. Quasielastic high-resolution time-of-flight spectrometers employing multi-disk chopper cascades for spallation sources

    International Nuclear Information System (INIS)

    Lechner, R.E.

    2001-01-01

    The design of multi-disk chopper time-of-flight (MTOF) spectrometers for high-resolution quasielastic and low-energy inelastic neutron scattering at spallation sources is discussed in some detail. A continuously variable energy resolution (1 μeV to 10 meV), and a large dynamic range (1 μeV to 100 meV), are outstanding features of this type of instrument, which are easily achieved also at a pulsed source using state-of-the-art technology. The method of intensity-resolution optimization of MTOF spectrometers at spallation sources is treated on the basis of the requirement of using (almost) 'all the neutrons of the pulse', taking into account the constant, but wavelength-dependent duration of the source pulse. It follows, that the optimization procedure (which is slightly different from that employed in the steady-state source case) should give priority to the highest resolution, whenever such a choice becomes necessary. This leads to long monochromator distances (L l2 ) of the order of 50 m, for achieving resolutions now available at reactor sources. A few examples of spectrometer layout and corresponding design parameters for large-angle and for small-angle quasielastic scattering instruments are given. In the latter case higher energy resolution than for large-angle scattering is required and achieved. The use of phase-space transformers, neutron wavelength band-pass filters and multichromatic operation for the purpose of intensity-resolution optimization are discussed. This spectrometer can be designed to make full use of the pulsed source peak flux. Therefore, and because of a number of improvements, high resolution will be available at high intensity: for any given resolution the total intensity at the detectors, when placed at one of the planned new spallation sources (SNS, JSNS, ESS, AUSTRON) will be larger by at least three orders of magnitude than the total intensity of any of the presently existing instruments of this type in routine operation at steady

  1. Writing performance assessments: how important is extended time?

    Science.gov (United States)

    Crawford, Lindy; Helwig, Robert; Tindal, Gerald

    2004-01-01

    Students in Grades 5 and 8 completed a 30-minute writing performance assessment and a writing performance assessment completed over 3 days. Assessments were evaluated on four traits (ideas, organization, conventions, and sentence fluency). A significant interaction was found at Grade 5 between length of time allotted for the assessment and students' educational classification (general or special education). Grade 5 students performed significantly better on the 3-day writing assessment, with students in special education benefiting the most. At Grade 8, there were no differences between scores on the 30-minute and the 3-day assessments. No significant differences were found in students' writing performance across various types of discourse (narrative, imaginative, persuasive, and expository); significant differences were reported across certain writing traits. We shared three hypotheses for reported differences: (a) students' proficiency with the writing process, (b) scoring scale bias, and (c) differences in the revision behaviors of developing and mature writers. Educational implications related to statewide test programs are discussed.

  2. The Impact of Cognitive Load on Operatic Singers’ Timing Performance.

    Directory of Open Access Journals (Sweden)

    Muzaffer eCorlu

    2015-04-01

    Full Text Available In the present paper, we report the results of an empirical study on the effects of cognitive load on operatic singing. The main aim of the study was to investigate to what extent a working memory task affected the timing of operatic singers’ performance. Thereby, we focused on singers’ tendency to speed up, or slow down their performance of musical phrases and pauses. Twelve professional operatic singers were asked to perform an operatic aria three times; once without an additional working memory task, once with a concurrent working memory task (counting shapes on a computer screen, and once with a relatively more difficult working memory task (more shapes to be counted appearing one after another. The results show that, in general, singers speeded up their performance under heightened cognitive load. Interestingly, this effect was more pronounced in pauses – more in particular longer pauses – compared to musical phrases. We discuss the role of sensorimotor control and feedback processes in musical timing to explain these findings.

  3. On the performance of diagonal lattice space-time codes

    KAUST Repository

    Abediseid, Walid

    2013-11-01

    There has been tremendous work done on designing space-time codes for the quasi-static multiple-input multiple output (MIMO) channel. All the coding design up-to-date focuses on either high-performance, high rates, low complexity encoding and decoding, or targeting a combination of these criteria [1]-[9]. In this paper, we analyze in details the performance limits of diagonal lattice space-time codes under lattice decoding. We present both lower and upper bounds on the average decoding error probability. We first derive a new closed-form expression for the lower bound using the so-called sphere lower bound. This bound presents the ultimate performance limit a diagonal lattice space-time code can achieve at any signal-to-noise ratio (SNR). The upper bound is then derived using the union-bound which demonstrates how the average error probability can be minimized by maximizing the minimum product distance of the code. Combining both the lower and the upper bounds on the average error probability yields a simple upper bound on the the minimum product distance that any (complex) lattice code can achieve. At high-SNR regime, we discuss the outage performance of such codes and provide the achievable diversity-multiplexing tradeoff under lattice decoding. © 2013 IEEE.

  4. Performance Evaluation and Market Timing: the Skill Index

    Directory of Open Access Journals (Sweden)

    Ney Roberto Otoni de Brito

    2003-01-01

    Full Text Available MERTON (1981 examines the creation of value by fund managers selecting between stocks and fixed income instruments through market timing. HENRIKSON and MERTON (1981 proceed to propose empirical tests of funds and manager performance in market timing. BRITO, BONA and TACIRO (2003 generalize the results of MERTON (1981 and HENRIKSON and MERTON (1981 for actively managed funds with a clearly defined benchmark portfolio. In the generalized context of active portfolio management, this paper proposes a new index – the Skill Index of Brito (SIB – to measure the performance and efficiency in market timing of actively managed funds. The paper proceeds to test the performance and skill of hedge funds in Brazil using the SIB. A representative sample of 32 hedge funds with a window of 90 trading days on October 31, 1999 was obtained. The empirical tests of performance and skill use the interbank borrowing and lending rate as the passive benchmark. The results indicate the significance at the 5% level of the SIB for ten hedge funds in the sample. Among them seven funds also have shown significance at the 1% level. In sum the results indicate a majority of hedge funds with no significant skill in the Brazilian market in the examined period.

  5. Statistical model based iterative reconstruction (MBIR) in clinical CT systems. Part II. Experimental assessment of spatial resolution performance

    International Nuclear Information System (INIS)

    Li, Ke; Chen, Guang-Hong; Garrett, John; Ge, Yongshuai

    2014-01-01

    Purpose: Statistical model based iterative reconstruction (MBIR) methods have been introduced to clinical CT systems and are being used in some clinical diagnostic applications. The purpose of this paper is to experimentally assess the unique spatial resolution characteristics of this nonlinear reconstruction method and identify its potential impact on the detectabilities and the associated radiation dose levels for specific imaging tasks. Methods: The thoracic section of a pediatric phantom was repeatedly scanned 50 or 100 times using a 64-slice clinical CT scanner at four different dose levels [CTDI vol =4, 8, 12, 16 (mGy)]. Both filtered backprojection (FBP) and MBIR (Veo ® , GE Healthcare, Waukesha, WI) were used for image reconstruction and results were compared with one another. Eight test objects in the phantom with contrast levels ranging from 13 to 1710 HU were used to assess spatial resolution. The axial spatial resolution was quantified with the point spread function (PSF), while the z resolution was quantified with the slice sensitivity profile. Both were measured locally on the test objects and in the image domain. The dependence of spatial resolution on contrast and dose levels was studied. The study also features a systematic investigation of the potential trade-off between spatial resolution and locally defined noise and their joint impact on the overall image quality, which was quantified by the image domain-based channelized Hotelling observer (CHO) detectability index d′. Results: (1) The axial spatial resolution of MBIR depends on both radiation dose level and image contrast level, whereas it is supposedly independent of these two factors in FBP. The axial spatial resolution of MBIR always improved with an increasing radiation dose level and/or contrast level. (2) The axial spatial resolution of MBIR became equivalent to that of FBP at some transitional contrast level, above which MBIR demonstrated superior spatial resolution than FBP (and

  6. A high-resolution time-of-flight spectrometer for fission fragments and ion beams

    International Nuclear Information System (INIS)

    Kosev, Krasimir Milchev

    2007-01-01

    For the purpose of fission-fragment detection a double time-of-flight (TOF) spectrometer has been developed. The key component of the TOF spectrometer is a TOF detector consisting of multichannel-plate (MCP) detectors with a position-sensitive readout, a foil for secondary electron (SE) production and an electrostatic mirror. The fission fragments are detected by measuring the SEs impinging on the position-sensitive anode after emission from the foil, acceleration and deflection by the electrostatic mirror. The functionality of the different detector components is proven in detail. Optimised schemes for the high-voltage supplies of the MCP detectors have been implemented successfully. In order to process the multichannel-plate detector signals optimally, a new state-of-the-art constant-fraction discriminator based on the amplitude and rise time compensated technique with very low threshold capabilities and optimised walk properties has been developed and incorporated into the setup. In a setup consisting of two mirror MCP detectors, we could successfully observe the TOF spectrum of a mixed ( 226 Ra, 222 Rn, 210 Po, 218 Po, 214 Po) α-source. Testing photo-fission experiments were performed at the bremsstrahlung facility at the ELBE accelerator. The setup consisted of two mirror detectors (first arm) and a 80 mm diameter MCP detector (second arm) with a 238 U target positioned in between. TOF measurements with two bremsstrahlung end-point energies of 12.9 and 16.0 MeV were carried out. A clear cut separation of the TOF peaks for the medium-mass and heavy fission fragments was observed. (orig.)

  7. A high-resolution time-of-flight spectrometer for fission fragments and ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Kosev, Krasimir Milchev

    2007-07-01

    For the purpose of fission-fragment detection a double time-of-flight (TOF) spectrometer has been developed. The key component of the TOF spectrometer is a TOF detector consisting of multichannel-plate (MCP) detectors with a position-sensitive readout, a foil for secondary electron (SE) production and an electrostatic mirror. The fission fragments are detected by measuring the SEs impinging on the position-sensitive anode after emission from the foil, acceleration and deflection by the electrostatic mirror. The functionality of the different detector components is proven in detail. Optimised schemes for the high-voltage supplies of the MCP detectors have been implemented successfully. In order to process the multichannel-plate detector signals optimally, a new state-of-the-art constant-fraction discriminator based on the amplitude and rise time compensated technique with very low threshold capabilities and optimised walk properties has been developed and incorporated into the setup. In a setup consisting of two mirror MCP detectors, we could successfully observe the TOF spectrum of a mixed ({sup 226}Ra,{sup 222}Rn,{sup 210}Po,{sup 218}Po,{sup 214}Po) {alpha}-source. Testing photo-fission experiments were performed at the bremsstrahlung facility at the ELBE accelerator. The setup consisted of two mirror detectors (first arm) and a 80 mm diameter MCP detector (second arm) with a {sup 238}U target positioned in between. TOF measurements with two bremsstrahlung end-point energies of 12.9 and 16.0 MeV were carried out. A clear cut separation of the TOF peaks for the medium-mass and heavy fission fragments was observed. (orig.)

  8. Performance of the high-resolution atmospheric model HRRR-AK for correcting geodetic observations from spaceborne radars.

    Science.gov (United States)

    Gong, W; Meyer, F J; Webley, P; Morton, D

    2013-10-27

    [1] Atmospheric phase delays are considered to be one of the main performance limitations for high-quality satellite radar techniques, especially when applied to ground deformation monitoring. Numerical weather prediction (NWP) models are widely seen as a promising tool for the mitigation of atmospheric delays as they can provide knowledge of the atmospheric conditions at the time of Synthetic Aperture Radar data acquisition. However, a thorough statistical analysis of the performance of using NWP production in radar signal correction is missing to date. This study provides a quantitative analysis of the accuracy in using operational NWP products for signal delay correction in satellite radar geodetic remote sensing. The study focuses on the temperate, subarctic, and Arctic climate regions due to a prevalence of relevant geophysical signals in these areas. In this study, the operational High Resolution Rapid Refresh over the Alaska region (HRRR-AK) model is used and evaluated. Five test sites were selected over Alaska (AK), USA, covering a wide range of climatic regimes that are commonly encountered in high-latitude regions. The performance of the HRRR-AK NWP model for correcting absolute atmospheric range delays of radar signals is assessed by comparing to radiosonde observations. The average estimation accuracy for the one-way zenith total atmospheric delay from 24 h simulations was calculated to be better than ∼14 mm. This suggests that the HRRR-AK operational products are a good data source for spaceborne geodetic radar observations atmospheric delay correction, if the geophysical signal to be observed is larger than 20 mm.

  9. Rapid High-throughput Species Identification of Botanical Material Using Direct Analysis in Real Time High Resolution Mass Spectrometry

    Science.gov (United States)

    Lesiak, Ashton D.; Musah, Rabi A.

    2016-01-01

    We demonstrate that direct analysis in real time-high resolution mass spectrometry can be used to produce mass spectral profiles of botanical material, and that these chemical fingerprints can be used for plant species identification. The mass spectral data can be acquired rapidly and in a high throughput manner without the need for sample extraction, derivatization or pH adjustment steps. The use of this technique bypasses challenges presented by more conventional techniques including lengthy chromatography analysis times and resource intensive methods. The high throughput capabilities of the direct analysis in real time-high resolution mass spectrometry protocol, coupled with multivariate statistical analysis processing of the data, provide not only class characterization of plants, but also yield species and varietal information. Here, the technique is demonstrated with two psychoactive plant products, Mitragyna speciosa (Kratom) and Datura (Jimsonweed), which were subjected to direct analysis in real time-high resolution mass spectrometry followed by statistical analysis processing of the mass spectral data. The application of these tools in tandem enabled the plant materials to be rapidly identified at the level of variety and species. PMID:27768072

  10. High Resolution Global Climate Modeling with GEOS-5: Intense Precipitation, Convection and Tropical Cyclones on Seasonal Time-Scales.

    Science.gov (United States)

    Putnam, WilliamM.

    2011-01-01

    In 2008 the World Modeling Summit for Climate Prediction concluded that "climate modeling will need-and is ready-to move to fundamentally new high-resolution approaches to capitalize on the seamlessness of the weather-climate continuum." Following from this, experimentation with very high-resolution global climate modeling has gained enhanced priority within many modeling groups and agencies. The NASA Goddard Earth Observing System model (GEOS-5) has been enhanced to provide a capability for the execution at the finest horizontal resolutions POS,SIOle with a global climate model today. Using this high-resolution, non-hydrostatic version of GEOS-5, we have developed a unique capability to explore the intersection of weather and climate within a seamless prediction system. Week-long weather experiments, to mUltiyear climate simulations at global resolutions ranging from 3.5- to 14-km have demonstrated the predictability of extreme events including severe storms along frontal systems, extra-tropical storms, and tropical cyclones. The primary benefits of high resolution global models will likely be in the tropics, with better predictions of the genesis stages of tropical cyclones and of the internal structure of their mature stages. Using satellite data we assess the accuracy of GEOS-5 in representing extreme weather phenomena, and their interaction within the global climate on seasonal time-scales. The impacts of convective parameterization and the frequency of coupling between the moist physics and dynamics are explored in terms of precipitation intensity and the representation of deep convection. We will also describe the seasonal variability of global tropical cyclone activity within a global climate model capable of representing the most intense category 5 hurricanes.

  11. A comparative study of the time performance between NINO and FlexToT ASICs

    Science.gov (United States)

    Sarasola, I.; Nemallapudi, M. V.; Gundacker, S.; Sánchez, D.; Gascón, D.; Rato, P.; Marín, J.; Auffray, E.

    2017-04-01

    Universitat de Barcelona (UB) and CIEMAT have designed the FlexToT ASIC for the front-end readout of SiPM-based scintillator detectors. This ASIC is aimed at time of flight (ToF) positron emission tomography (PET) applications. In this work we have evaluated the time performance of the FlexToT v2 ASIC compared to the NINO ASIC, a fast ASIC developped at CERN. NINO electronics give 64 ps sigma for single-photon time resolution (SPTR) and 93 ps FWHM for coincidence time resolution (CTR) with 2 × 2 × 5 mm3 LSO:Ce,Ca crystals and S13360-3050CS SiPMs. Using the same SiPMs and crystals, the FlexToT v2 ASIC yields 91 ps sigma for SPTR and 123 ps FWHM for CTR. Despite worse time performace than NINO, FlexToT v2 features lower power consumption (11 vs. 27 mW/ch) and linear ToT energy measurement.

  12. A comparative study of the time performance between NINO and FlexToT ASICs

    International Nuclear Information System (INIS)

    Sarasola, I.; Rato, P.; Marín, J.; Nemallapudi, M.V.; Gundacker, S.; Auffray, E.; Sánchez, D.; Gascón, D.

    2017-01-01

    Universitat de Barcelona (UB) and CIEMAT have designed the FlexToT ASIC for the front-end readout of SiPM-based scintillator detectors. This ASIC is aimed at time of flight (ToF) positron emission tomography (PET) applications. In this work we have evaluated the time performance of the FlexToT v2 ASIC compared to the NINO ASIC, a fast ASIC developped at CERN. NINO electronics give 64 ps sigma for single-photon time resolution (SPTR) and 93 ps FWHM for coincidence time resolution (CTR) with 2 × 2 × 5 mm 3 LSO:Ce,Ca crystals and S13360-3050CS SiPMs. Using the same SiPMs and crystals, the FlexToT v2 ASIC yields 91 ps sigma for SPTR and 123 ps FWHM for CTR. Despite worse time performace than NINO, FlexToT v2 features lower power consumption (11 vs. 27 mW/ch) and linear ToT energy measurement.

  13. Real-time mosaic - rapid response, high resolution imaging from space

    Science.gov (United States)

    da Silva Curiel, A.; Wazni, M.; Boland, Lee; Davies, Phil; Eves, Stuart; Sun, Wei; Sweeting, Martin

    2004-11-01

    An imaging constellation mission is proposed to provide near-continuous surveillance of regional activity. By introducing a multiple plane constellation of small Earth Observation satellites, it is possible to monitor selected parts of the entire globe several times during daylight. Using off-the-shelf microsatellites ensures the program is responsive in the deployment phase as well as in the operational phase. The paper describes the basic Disaster Monitoring Constellation programme as has been implemented, which already delivers daily imagery. It also describes the system trades of the regional imaging constellations, and outlines the scope of the performance that could be obtained from such a system. A cost model illustrates that the balance between launch and space segment costs must be reached by considering suitable replacement strategies, and that the system is highly sensitive to requirement creep. Finally, it is shown that the use of cost effective, small satellites leads to solutions previously thought to be out of reach of Earth Science and Government customers.

  14. Training high performance skills using above real-time training

    Science.gov (United States)

    Guckenberger, Dutch; Uliano, Kevin C.; Lane, Norman E.

    1993-01-01

    The Above Real-Time Training (ARTT) concept is a unique approach to training high performance skills. ARTT refers to a training paradigm that places the operator in a simulated environment that functions at faster than normal time. Such a training paradigm represents a departure from the intuitive, but not often supported, feeling that the best practice is determined by the training environment with the highest fidelity. This approach is hypothesized to provide greater 'transfer value' per simulation trial, by incorporating training techniques and instructional features into the simulator. These techniques allow individuals to acquire these critical skills faster and with greater retention. ARTT also allows an individual trained in 'fast time' to operate at what appears to be a more confident state, when the same task is performed in a real-time environment. Two related experiments are discussed. The findings appear to be consistent with previous findings that show positive effects of task variation during training. Moreover, ARTT has merit in improving or maintaining transfer with sharp reductions in training time. There are indications that the effectiveness of ARTT varies as a function of task content and possibly task difficulty. Other implications for ARTT are discussed along with future research directions.

  15. Real-time pure shift 15N HSQC of proteins: a real improvement in resolution and sensitivity

    International Nuclear Information System (INIS)

    Kiraly, Peter; Adams, Ralph W.; Paudel, Liladhar; Foroozandeh, Mohammadali; Aguilar, Juan A.; Timári, István; Cliff, Matthew J.; Nilsson, Mathias; Sándor, Péter; Batta, Gyula; Waltho, Jonathan P.; Kövér, Katalin E.; Morris, Gareth A.

    2015-01-01

    Spectral resolution in proton NMR spectroscopy is reduced by the splitting of resonances into multiplets due to the effect of homonuclear scalar couplings. Although these effects are often hidden in protein NMR spectroscopy by low digital resolution and routine apodization, behind the scenes homonuclear scalar couplings increase spectral overcrowding. The possibilities for biomolecular NMR offered by new pure shift NMR methods are illustrated here. Both resolution and sensitivity are improved, without any increase in experiment time. In these experiments, free induction decays are collected in short bursts of data acquisition, with durations short on the timescale of J-evolution, interspersed with suitable refocusing elements. The net effect is real-time (t 2 ) broadband homodecoupling, suppressing the multiplet structure caused by proton–proton interactions. The key feature of the refocusing elements is that they discriminate between the resonances of active (observed) and passive (coupling partner) spins. This can be achieved either by using band-selective refocusing or by the BIRD element, in both cases accompanied by a nonselective 180° proton pulse. The latter method selects the active spins based on their one-bond heteronuclear J-coupling to 15 N, while the former selects a region of the 1 H spectrum. Several novel pure shift experiments are presented, and the improvements in resolution and sensitivity they provide are evaluated for representative samples: the N-terminal domain of PGK; ubiquitin; and two mutants of the small antifungal protein PAF. These new experiments, delivering improved sensitivity and resolution, have the potential to replace the current standard HSQC experiments

  16. Real-time pure shift {sup 15}N HSQC of proteins: a real improvement in resolution and sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Kiraly, Peter; Adams, Ralph W.; Paudel, Liladhar; Foroozandeh, Mohammadali [University of Manchester, School of Chemistry (United Kingdom); Aguilar, Juan A. [Durham University, Department of Chemistry (United Kingdom); Timári, István [University of Debrecen, Department of Inorganic and Analytical Chemistry (Hungary); Cliff, Matthew J. [University of Manchester, Manchester Institute of Biotechnology (United Kingdom); Nilsson, Mathias [University of Manchester, School of Chemistry (United Kingdom); Sándor, Péter [Agilent Technologies R& D and Marketing GmbH & Co. KG (Germany); Batta, Gyula [University of Debrecen, Department of Organic Chemistry (Hungary); Waltho, Jonathan P. [University of Manchester, Manchester Institute of Biotechnology (United Kingdom); Kövér, Katalin E. [University of Debrecen, Department of Inorganic and Analytical Chemistry (Hungary); Morris, Gareth A., E-mail: g.a.morris@manchester.ac.uk [University of Manchester, School of Chemistry (United Kingdom)

    2015-05-15

    Spectral resolution in proton NMR spectroscopy is reduced by the splitting of resonances into multiplets due to the effect of homonuclear scalar couplings. Although these effects are often hidden in protein NMR spectroscopy by low digital resolution and routine apodization, behind the scenes homonuclear scalar couplings increase spectral overcrowding. The possibilities for biomolecular NMR offered by new pure shift NMR methods are illustrated here. Both resolution and sensitivity are improved, without any increase in experiment time. In these experiments, free induction decays are collected in short bursts of data acquisition, with durations short on the timescale of J-evolution, interspersed with suitable refocusing elements. The net effect is real-time (t{sub 2}) broadband homodecoupling, suppressing the multiplet structure caused by proton–proton interactions. The key feature of the refocusing elements is that they discriminate between the resonances of active (observed) and passive (coupling partner) spins. This can be achieved either by using band-selective refocusing or by the BIRD element, in both cases accompanied by a nonselective 180° proton pulse. The latter method selects the active spins based on their one-bond heteronuclear J-coupling to {sup 15}N, while the former selects a region of the {sup 1}H spectrum. Several novel pure shift experiments are presented, and the improvements in resolution and sensitivity they provide are evaluated for representative samples: the N-terminal domain of PGK; ubiquitin; and two mutants of the small antifungal protein PAF. These new experiments, delivering improved sensitivity and resolution, have the potential to replace the current standard HSQC experiments.

  17. Optimizing the Time Performance of Subcontractors in Building Projects

    Directory of Open Access Journals (Sweden)

    Andrew D.F Price

    2010-07-01

    Full Text Available  The main contractors of Hong Kong building projects tend to subcontract most of their work. However, many of the subcontractors complain that they are not being fully utilized due main contractors’ poor site coordination of temporary works and interfacing works and plant supports etc. A list of critical site coordination problems caused by main contractors that had adversely influence to the time performance of subcontractors was prepared. A questionnaire survey was conducted to collect data to generate multiple regression equations that explain how the critical site coordination problems affected the time performance of different types of subcontractor. The survey results were validated by neural network analysis. Backward elimination method was adopted to identify the ‘most critical’ site coordination problems that enable main contractors to formulate measures to enhance their site management system.

  18. High Performance Embedded System for Real-Time Pattern Matching

    CERN Document Server

    Sotiropoulou, Calliope Louisa; The ATLAS collaboration; Gkaitatzis, Stamatios; Citraro, Saverio; Giannetti, Paola; Dell'Orso, Mauro

    2016-01-01

    We present an innovative and high performance embedded system for real-time pattern matching. This system is based on the evolution of hardware and algorithms developed for the field of High Energy Physics (HEP) and more specifically for the execution of extremely fast pattern matching for tracking of particles produced by proton-proton collisions in hadron collider experiments. A miniaturized version of this complex system is being developed for pattern matching in generic image processing applications. The design uses the flexibility of Field Programmable Gate Arrays (FPGAs) and the powerful Associative Memory Chip (ASIC) to achieve real-time performance. The system works as a contour identifier able to extract the salient features of an image. It is based on the principles of cognitive image processing, which means that it executes fast pattern matching and data reduction mimicking the operation of the human brain.

  19. Improved Span Time Performance in NPD Using Better Coordination

    OpenAIRE

    Suss, Samuel; Thomson, Vince

    2012-01-01

    Part 3: Tools and Methodologies; International audience; New product development (NPD) processes are characterized by uncertainty and iteration making them difficult to plan and manage. A novel dynamic model of NPD that explicitly models communication techniques is used to examine ways to improve span time and effort performance through improved coordination. Results of simulations under various scenarios of epistemic and aleatory uncertainty illustrate how coordination and adapting agile NPD...

  20. Time and isolation as performance art: A note

    OpenAIRE

    O'Donnell, Ian

    2014-01-01

    In a series of five year-long works the Taiwanese-American artist Tehching Hsieh captured critical aspects of the prisoner’s experience including the meaning of time, the rigours of solitary confinement, the impact of homelessness and the pressures of inescapable company. These were performed in unambiguously stark, and deeply personal, terms. In a way these pieces of art might be considered partial prison parables which point to, but do not explicate, lessons from which anyone deprived of th...

  1. Impact of rainfall temporal resolution on urban water quality modelling performance and uncertainties.

    Science.gov (United States)

    Manz, Bastian Johann; Rodríguez, Juan Pablo; Maksimović, Cedo; McIntyre, Neil

    2013-01-01

    A key control on the response of an urban drainage model is how well the observed rainfall records represent the real rainfall variability. Particularly in urban catchments with fast response flow regimes, the selection of temporal resolution in rainfall data collection is critical. Furthermore, the impact of the rainfall variability on the model response is amplified for water quality estimates, as uncertainty in rainfall intensity affects both the rainfall-runoff and pollutant wash-off sub-models, thus compounding uncertainties. A modelling study was designed to investigate the impact of altering rainfall temporal resolution on the magnitude and behaviour of uncertainties associated with the hydrological modelling compared with water quality modelling. The case study was an 85-ha combined sewer sub-catchment in Bogotá (Colombia). Water quality estimates showed greater sensitivity to the inter-event variability in rainfall hyetograph characteristics than to changes in the rainfall input temporal resolution. Overall, uncertainties from the water quality model were two- to five-fold those of the hydrological model. However, owing to the intrinsic scarcity of observations in urban water quality modelling, total model output uncertainties, especially from the water quality model, were too large to make recommendations for particular model structures or parameter values with respect to rainfall temporal resolution.

  2. The effect of image resolution on the performance of a face recognition system

    NARCIS (Netherlands)

    Boom, B.J.; Beumer, G.M.; Spreeuwers, Lieuwe Jan; Veldhuis, Raymond N.J.

    2006-01-01

    In this paper we investigate the effect of image resolution on the error rates of a face verification system. We do not restrict ourselves to the face recognition algorithm only, but we also consider the face registration. In our face recognition system, the face registration is done by finding

  3. Performance Analysis of Statistical Time Division Multiplexing Systems

    Directory of Open Access Journals (Sweden)

    Johnson A. AJIBOYE

    2010-12-01

    Full Text Available Multiplexing is a way of accommodating many input sources of a low capacity over a high capacity outgoing channel. Statistical Time Division Multiplexing (STDM is a technique that allows the number of users to be multiplexed over the channel more than the channel can afford. The STDM normally exploits unused time slots by the non-active users and allocates those slots for the active users. Therefore, STDM is appropriate for bursty sources. In this way STDM normally utilizes channel bandwidth better than traditional Time Division Multiplexing (TDM. In this work, the statistical multiplexer is viewed as M/M/1queuing system and the performance is measured by comparing analytical results to simulation results using Matlab. The index used to determine the performance of the statistical multiplexer is the number of packets both in the system and the queue. Comparison of analytical results was also done between M/M/1 and M/M/2 and also between M/M/1 and M/D/1 queue systems. At high utilizations, M/M/2 performs better than M/M/1. M/D/1 also outperforms M/M1.

  4. Sensitivity of isoprene emissions estimated using MEGAN to the time resolution of input climate data

    Directory of Open Access Journals (Sweden)

    K. Ashworth

    2010-02-01

    Full Text Available We evaluate the effect of varying the temporal resolution of the input climate data on isoprene emission estimates generated by the community emissions model MEGAN (Model of Emissions of Gases and Aerosols from Nature. The estimated total global annual emissions of isoprene is reduced from 766 Tg y−1 when using hourly input data to 746 Tg y−1 (a reduction of 3% for daily average input data and 711 Tg y−1 (down 7% for monthly average input data. The impact on a local scale can be more significant with reductions of up to 55% at some locations when using monthly average data compared with using hourly data. If the daily and monthly average temperature data are used without the imposition of a diurnal cycle the global emissions estimates fall by 27–32%, and local annual emissions by up to 77%. A similar pattern emerges if hourly isoprene fluxes are considered. In order to better simulate and predict isoprene emission rates using MEGAN, we show it is necessary to use temperature and radiation data resolved to one hour. Given the importance of land-atmosphere interactions in the Earth system and the low computational cost of the MEGAN algorithms, we recommend that chemistry-climate models and the new generation of Earth system models input biogenic emissions at the highest temporal resolution possible.

  5. Sodium Phosphate Supplementation and Time Trial Performance in Female Cyclists

    Directory of Open Access Journals (Sweden)

    Christopher L. Buck

    2014-09-01

    Full Text Available This study investigated the effects of three doses of sodium phosphate (SP supplementation on cycling 500 kJ (119.5 Kcal time trial (TT performance in female cyclists. Thirteen cyclists participated in a randomised, Latin-square design study where they completed four separate trials after ingesting either a placebo, or one of three different doses (25, 50 or 75 mg·kg-1 fat free mass: FFM of trisodium phosphate dodecahydrate which was split into four equal doses a day for six days. On the day after the loading phase, the TT was performed on a cycle ergometer. Serum phosphate blood samples were taken at rest both before and after each loading protocol, while a ~21 day washout period separated each loading phase. No significant differences in TT performance were observed between any of the supplementation protocols (p = 0.73 with average completion times for the 25, 50 or 75 mg·kg-1 FFM being, 42:21 ± 07:53, 40:55 ± 07:33 and 40:38 ± 07:20 min respectively, and 40:39 ± 07:51 min for the placebo. Likewise, average and peak power output did not significantly differ between trials (p = 0.06 and p = 0.46, respectively. Consequently, 500 kJ cycling TT performance was not different in any of the supplementation protocols in female cyclists.

  6. Investigating the tradeoffs between spatial resolution and diffusion sampling for brain mapping with diffusion tractography: time well spent?

    Science.gov (United States)

    Calabrese, Evan; Badea, Alexandra; Coe, Christopher L; Lubach, Gabriele R; Styner, Martin A; Johnson, G Allan

    2014-11-01

    Interest in mapping white matter pathways in the brain has peaked with the recognition that altered brain connectivity may contribute to a variety of neurologic and psychiatric diseases. Diffusion tractography has emerged as a popular method for postmortem brain mapping initiatives, including the ex-vivo component of the human connectome project, yet it remains unclear to what extent computer-generated tracks fully reflect the actual underlying anatomy. Of particular concern is the fact that diffusion tractography results vary widely depending on the choice of acquisition protocol. The two major acquisition variables that consume scan time, spatial resolution, and diffusion sampling, can each have profound effects on the resulting tractography. In this analysis, we determined the effects of the temporal tradeoff between spatial resolution and diffusion sampling on tractography in the ex-vivo rhesus macaque brain, a close primate model for the human brain. We used the wealth of autoradiography-based connectivity data available for the rhesus macaque brain to assess the anatomic accuracy of six time-matched diffusion acquisition protocols with varying balance between spatial and diffusion sampling. We show that tractography results vary greatly, even when the subject and the total acquisition time are held constant. Further, we found that focusing on either spatial resolution or diffusion sampling at the expense of the other is counterproductive. A balanced consideration of both sampling domains produces the most anatomically accurate and consistent results. Copyright © 2014 Wiley Periodicals, Inc.

  7. A Study of Correlations among Image Resolution, Reaction Time, and Extent of Motion in Remote Motor Interactions

    Directory of Open Access Journals (Sweden)

    Zoltán Rusák

    2014-01-01

    Full Text Available Motor interaction in virtual sculpting, dance trainings, and physiological rehabilitation requires close virtual proximity of users, which may be hindered by low resolution of images and system latency. This paper reports on the results of our investigation aiming to explore the pros and cons of using ultrahigh 4K resolution displays (4096 × 2160 pixels in remote motor interaction. 4K displays are able to overcome the problem of visible pixels and they are able to show more accurate image details on the level of textures, shadows, and reflections. It was our assumption that such image details can not only satisfy visual comfort of the users, but also provide detailed visual cues and improve the reaction time of users in motor interaction. To validate this hypothesis, we explored the relationships between the reaction time of subjects responding to a series of action-reaction type of games and resolution of the image used in an experiment. The results of our experiment showed that the subjects’ reaction time is significantly shorter in 4K images than in HD or VGA images in motor interaction with small motion envelope.

  8. Salish Sea Nowcast: A Real-time High-Resolution Model for Forecasts and Research Support

    Science.gov (United States)

    Latornell, D.; Allen, S. E.; Soontiens, N. K.; Dunn, M. B. H.; Liu, J.; Machuca, I.

    2016-02-01

    The Salish Sea real-time model system produces two forecasts and a nowcast daily, providing storm surge forecasts for several municipality stakeholders.Without human intervention, the automation system collects the required forcing data from various web services, runs the model and publishes results in the form of plots on several web pages.Here we will present the automation framework that enables a research model to be run operationally.The automation runs across two computer systems with a cloud computing facility running the numerical model (NEMO in our case), and a local Linux server doing everything else.The system has a modular, asynchronous architecture that is coordinated by a messaging framework.A manager process coordinates the sequencing and operation of a collection of worker processes each responsible for a specific task in the preparation for a model run, execution of the run, analysis, visualization, and publication to the web of the run results.Techniques that make the system reasonably fault tolerant will be discussed.The modular design easily allows researchers with a variety of skill sets to contribute to the framework to the benefit of the project and its knowledge transfer to stakeholders.We will discuss the performance of the system during the 2014-2016 storm surge seasons,and routine evaluation against sea surface height observation data streams.Daily model runs with best available weather and river runoff forcing facilitate continuous evaluation against cabled observatory data streams.We will show how those evaluations provide important insights that help to driveresearch that improves the model.

  9. Timing performance of pixellated CdZnTe detectors

    International Nuclear Information System (INIS)

    Amrami, R.; Shami, G.; Hefetz, Y.; Pansky, A.; Wainer, N.

    1999-01-01

    Recently introduced nuclear medicine cameras in which Positron Emission Tomography (PET) and the traditional Single Photon Emission Computerized Tomography (SPECT), are combined opened new horizon for the nuclear medicine field These systems applying NaI(Tl) scintillation detectors we very well tested and mailable for some time in the medical imaging field However the traditional NaI(Tl) cameras, optimized for low energy radiation imaging, suffer some severe limitations. The relatively low density (3.67 g/cm 2 ) of NaI(Tl) limits the sensitivity. By incarcerating the NaI(Tl) thickness, the spatial resolution decreases. The long decay time (230 nsec) of the light emitted in NaI(Tl) restricts the the use of coincidence technique , as well as the count rate. In recent years CdZn Te (CZT) detectors are studied for the purpose of SPECT nuclear medical radiation imaging in the form of pixellated and microstrip detectors. CZT detector can served as a good candidate for replacing NaI(Tl) for PET and SPECT imaging due to their relatively high stopping power (density = (6.0 g/im 3 , high Z(48, 30, 52)) and their high count rate capability. Unfortunately there are several difficulties in PET application due to the difficulty in manufacturing thick crystals, registration of the full energy deposited in several pixels and their timing capabilities. The latter is due to large ballistic signal variation induced. This variations caused by the pulse shape, which is composed of two main components, the electron and the hole. The electrons travel about ten times faster than the holes. A photon absorbed clear the cathode plane will cause a large and fast signal induced by the electron and a small and slow signal induced due to the holes. Photons absorbed near the anode plane will induce the opposite signals. The distribution of photon absorption depth in the crystal causes signal splits over a number of pixels, due to the well-known 'small pixel effect'. The different pulses slope

  10. Design and performance of a high rate, high angular resolution beam telescope used for crystal channeling studies

    International Nuclear Information System (INIS)

    Pesaresi, M; Ferguson, W; Fulcher, J; Hall, G; Raymond, M; Ryan, M; Zorba, O

    2011-01-01

    A charged particle telescope has been constructed for data taking at high rates in a CERN 400 GeV/c proton beam line. It utilises ten planes of silicon microstrip sensors, arranged as five pairs each measuring two orthogonal coordinates, with an active area of 3.8 x 3.8 cm 2 . The objective was to provide excellent angular and spatial resolution for measuring the trajectories of incident and outgoing particles. The apparatus has a long baseline, of approximately 10 m in each arm, and achieves an angular resolution in the incoming arm of 2.8 μrad and a total angular resolution on the difference of the two arms of 5.2 μrad, with performance limited by multiple scattering in the sensor layers. The sensors are instrumented by a system based on the CMS Tracker electronic readout chain, including analogue signal readout for optimal spatial resolution. The system profits from modified CMS software and hardware to provide a data acquisition capable of peak trigger rates of at least 7 kHz. We describe the sensor readout, electronic hardware and software, together with the measured performance of the telescope during studies of crystal channeling for the UA9 collaboration. Measurements of a previously unobserved periodic movement of the beam are also presented and the significance of such an effect for precise studies such as for channeling is discussed.

  11. HIGH RESOLUTION PREDICTION OF GAS INJECTION PROCESS PERFORMANCE FOR HETEROGENEOUS RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Franklin M. Orr, Jr.

    2004-05-01

    This final technical report describes and summarizes results of a research effort to investigate physical mechanisms that control the performance of gas injection processes in heterogeneous reservoirs and to represent those physical effects in an efficient way in simulations of gas injection processes. The research effort included four main lines of research: (1) Efficient compositional streamline methods for 3D flow; (2) Analytical methods for one-dimensional displacements; (3) Physics of multiphase flow; and (4) Limitations of streamline methods. In the first area, results are reported that show how the streamline simulation approach can be applied to simulation of gas injection processes that include significant effects of transfer of components between phases. In the second area, the one-dimensional theory of multicomponent gas injection processes is extended to include the effects of volume change as components change phase. In addition an automatic algorithm for solving such problems is described. In the third area, results on an extensive experimental investigation of three-phase flow are reported. The experimental results demonstrate the impact on displacement performance of the low interfacial tensions between the gas and oil phases that can arise in multicontact miscible or near-miscible displacement processes. In the fourth area, the limitations of the streamline approach were explored. Results of an experimental investigation of the scaling of the interplay of viscous, capillary, and gravity forces are described. In addition results of a computational investigation of the limitations of the streamline approach are reported. The results presented in this report establish that it is possible to use the compositional streamline approach in many reservoir settings to predict performance of gas injection processes. When that approach can be used, it requires substantially less (often orders of magnitude) computation time than conventional finite difference

  12. Analysis of veterinary drug and pesticide residues in animal feed by high-resolution mass spectrometry: comparison between time-of-flight and Orbitrap.

    Science.gov (United States)

    Gómez-Pérez, María Luz; Romero-González, Roberto; Martínez Vidal, José Luis; Garrido Frenich, Antonia

    2015-01-01

    The use of medium-high-resolution mass spectrometers (M-HRMS) provides many advantages in multi-residue analysis. A comparison between two mass spectrometers, medium-resolution (MRMS) time-of-flight (TOF) and high-resolution (HRMS) Orbitrap, has been carried out for the analysis of toxic compounds in animal feed. More than 300 compounds belonging to several classes of veterinary drugs (VDs) and pesticides have been determined in different animal feed samples using a generic extraction method. The use of a clean-up procedure has been evaluated in both instruments, and several validation parameters have been established, such as the matrix effect, linearity, recovery and sensitivity. Finally, both instruments have been used during the analysis of 18 different feed samples (including chicken, hen, rabbit and horse). Some VDs (sulfadiazine, trimethoprim, robenidine and monensin sodium) and one pesticide (chlorpyrifos) have been identified. In general, better results were obtained using the Orbitrap, such as sensitivity (1-12.5 µg kg(-1)) and recovery values (60-125%). Moreover, this analyser had several software tools, which reduced the time for data processing and were easy to use, performing quick screening for more than 450 compounds in less than 5 min. However, some disadvantages such as the high cost and a decrease in the number of detected compounds at low concentrations must be taken into account.

  13. Enhancement of Temporal Resolution and BOLD Sensitivity in Real-Time fMRI using Multi-Slab Echo-Volumar Imaging

    Science.gov (United States)

    Posse, Stefan; Ackley, Elena; Mutihac, Radu; Rick, Jochen; Shane, Matthew; Murray-Krezan, Cristina; Zaitsev, Maxim; Speck, Oliver

    2012-01-01

    In this study, a new approach to high-speed fMRI using multi-slab echo-volumar imaging (EVI) is developed that minimizes geometrical image distortion and spatial blurring, and enables nonaliased sampling of physiological signal fluctuation to increase BOLD sensitivity compared to conventional echo-planar imaging (EPI). Real-time fMRI using whole brain 4-slab EVI with 286 ms temporal resolution (4 mm isotropic voxel size) and partial brain 2-slab EVI with 136 ms temporal resolution (4×4×6 mm3 voxel size) was performed on a clinical 3 Tesla MRI scanner equipped with 12-channel head coil. Four-slab EVI of visual and motor tasks significantly increased mean (visual: 96%, motor: 66%) and maximum t-score (visual: 263%, motor: 124%) and mean (visual: 59%, motor: 131%) and maximum (visual: 29%, motor: 67%) BOLD signal amplitude compared with EPI. Time domain moving average filtering (2 s width) to suppress physiological noise from cardiac and respiratory fluctuations further improved mean (visual: 196%, motor: 140%) and maximum (visual: 384%, motor: 200%) t-scores and increased extents of activation (visual: 73%, motor: 70%) compared to EPI. Similar sensitivity enhancement, which is attributed to high sampling rate at only moderately reduced temporal signal-to-noise ratio (mean: − 52%) and longer sampling of the BOLD effect in the echo-time domain compared to EPI, was measured in auditory cortex. Two-slab EVI further improved temporal resolution for measuring task-related activation and enabled mapping of five major resting state networks (RSNs) in individual subjects in 5 min scans. The bilateral sensorimotor, the default mode and the occipital RSNs were detectable in time frames as short as 75 s. In conclusion, the high sampling rate of real-time multi-slab EVI significantly improves sensitivity for studying the temporal dynamics of hemodynamic responses and for characterizing functional networks at high field strength in short measurement times. PMID:22398395

  14. Rapid simultaneous high-resolution mapping of myelin water fraction and relaxation times in human brain using BMC-mcDESPOT.

    Science.gov (United States)

    Bouhrara, Mustapha; Spencer, Richard G

    2017-02-15

    A number of central nervous system (CNS) diseases exhibit changes in myelin content and magnetic resonance longitudinal, T 1 , and transverse, T 2 , relaxation times, which therefore represent important biomarkers of CNS pathology. Among the methods applied for measurement of myelin water fraction (MWF) and relaxation times, the multicomponent driven equilibrium single pulse observation of T 1 and T 2 (mcDESPOT) approach is of particular interest. mcDESPOT permits whole brain mapping of multicomponent T 1 and T 2 , with data acquisition accomplished within a clinically realistic acquisition time. Unfortunately, previous studies have indicated the limited performance of mcDESPOT in the setting of the modest signal-to-noise range of high-resolution mapping, required for the depiction of small structures and to reduce partial volume effects. Recently, we showed that a new Bayesian Monte Carlo (BMC) analysis substantially improved determination of MWF from mcDESPOT imaging data. However, our previous study was limited in that it did not discuss determination of relaxation times. Here, we extend the BMC analysis to the simultaneous determination of whole-brain MWF and relaxation times using the two-component mcDESPOT signal model. Simulation analyses and in-vivo human brain studies indicate the overall greater performance of this approach compared to the stochastic region contraction (SRC) algorithm, conventionally used to derive parameter estimates from mcDESPOT data. SRC estimates of the transverse relaxation time of the long T 2 fraction, T 2,l , and the longitudinal relaxation time of the short T 1 fraction, T 1,s , clustered towards the lower and upper parameter search space limits, respectively, indicating failure of the fitting procedure. We demonstrate that this effect is absent in the BMC analysis. Our results also showed improved parameter estimation for BMC as compared to SRC for high-resolution mapping. Overall we find that the combination of BMC analysis

  15. Pseudoephedrine ingestion and cycling time-trial performance.

    Science.gov (United States)

    Pritchard-Peschek, Kellie R; Jenkins, David G; Osborne, Mark A; Slater, Gary J

    2010-04-01

    The aim of the current study was to investigate the effect of 180 mg of pseudoephedrine (PSE) on cycling time-trial (TT) performance. Six well-trained male cyclists and triathletes (age 33 +/- 2 yr, mass 81 +/- 8 kg, height 182.0 +/- 6.7 cm, VO2max 56.8 +/- 6.8 ml x kg(-1) x min(-1); M +/- SD) underwent 2 performance trials in which they completed a 25-min variable-intensity (50-90% maximal aerobic power) warm-up, followed by a cycling TT in which they completed a fixed amount of work (7 kJ/kg body mass) in the shortest possible time. Sixty minutes before the start of exercise, they orally ingested 180 mg of PSE or a cornstarch placebo (PLA) in a randomized, crossover, double-blind manner. Venous blood was sampled immediately pre- and postexercise for the analysis of pH plus lactate, glucose, and norepinephrine (NE). PSE improved cycling TT performance by 5.1% (95% CI 0-10%) compared with PLA (28:58.9 +/- 4:26.5 and 30:31.7 +/- 4:36.7 min, respectively). There was a significant Treatment x Time interaction (p = .04) for NE, with NE increasing during the PSE trial only. Similarly, blood glucose also showed a trend (p = .06) for increased levels postexercise in the PSE trial. The ingestion of 180 mg of PSE 60 min before the onset of high-intensity exercise improved cycling TT performance in well-trained athletes. It is possible that changes in metabolism or an increase in central nervous system stimulation is responsible for the observed ergogenic effect of PSE.

  16. Time's up! Involvement of metamemory knowledge, executive functions, and time monitoring in children's prospective memory performance.

    Science.gov (United States)

    Geurten, Marie; Lejeune, Caroline; Meulemans, Thierry

    2016-01-01

    This study examined time-based prospective memory (PM) in children and explored the possible involvement of metamemory knowledge and executive functions in the use of an appropriate time-monitoring strategy depending on the ongoing task's difficulty. Specifically, a sample of 72 typically developing children aged 4, 6, and 9 years old were given an original PM paradigm composed of both an ongoing procedural activity and a PM task. Half of the participants (expert group) were trained in the ongoing activity before the prospective test. As expected, results show that time monitoring had a positive effect on children's PM performance. Furthermore, mediation analyses reveal that strategic time monitoring was predicted by metamemory knowledge in the expert group but only by executive functions in the novice group. Overall, these findings provide interesting avenues to explain how metamemory knowledge, strategy use, and executive functions interact to improve PM performance during childhood.

  17. Stochastic nonlinear time series forecasting using time-delay reservoir computers: performance and universality.

    Science.gov (United States)

    Grigoryeva, Lyudmila; Henriques, Julie; Larger, Laurent; Ortega, Juan-Pablo

    2014-07-01

    Reservoir computing is a recently introduced machine learning paradigm that has already shown excellent performances in the processing of empirical data. We study a particular kind of reservoir computers called time-delay reservoirs that are constructed out of the sampling of the solution of a time-delay differential equation and show their good performance in the forecasting of the conditional covariances associated to multivariate discrete-time nonlinear stochastic processes of VEC-GARCH type as well as in the prediction of factual daily market realized volatilities computed with intraday quotes, using as training input daily log-return series of moderate size. We tackle some problems associated to the lack of task-universality for individually operating reservoirs and propose a solution based on the use of parallel arrays of time-delay reservoirs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Sodium Phosphate Supplementation and Time Trial Performance in Female Cyclists

    Science.gov (United States)

    Buck, Christopher L.; Dawson, Brian; Guelfi, Kym J.; McNaughton, Lars; Wallman, Karen E.

    2014-01-01

    This study investigated the effects of three doses of sodium phosphate (SP) supplementation on cycling 500 kJ (119.5 Kcal) time trial (TT) performance in female cyclists. Thirteen cyclists participated in a randomised, Latin-square design study where they completed four separate trials after ingesting either a placebo, or one of three different doses (25, 50 or 75 mg·kg-1 fat free mass: FFM) of trisodium phosphate dodecahydrate which was split into four equal doses a day for six days. On the day after the loading phase, the TT was performed on a cycle ergometer. Serum phosphate blood samples were taken at rest both before and after each loading protocol, while a ~21 day washout period separated each loading phase. No significant differences in TT performance were observed between any of the supplementation protocols (p = 0.73) with average completion times for the 25, 50 or 75 mg·kg-1 FFM being, 42:21 ± 07:53, 40:55 ± 07:33 and 40:38 ± 07:20 min respectively, and 40:39 ± 07:51 min for the placebo. Likewise, average and peak power output did not significantly differ between trials (p = 0.06 and p = 0.46, respectively). Consequently, 500 kJ cycling TT performance was not different in any of the supplementation protocols in female cyclists. Key Points No significant benefit of a 25, 50 or 75 mg·kg-1 of FFM dose of sodium phosphate was found on 500 kJ (119.5 Kcal) TT cycle performance in female cyclists. Females of differing fitness levels responded similarly to sodium phosphate supplementation. Due to the possibility of individual responders to either the 50 or 75 mg·kg-1 of FFM loading protocols, competitive cyclists should trial these doses prior to competition. PMID:25177171

  19. A High-Granularity Timing Detector (HGTD) in ATLAS : Performance at the HL-LHC

    CERN Document Server

    Allaire, Corentin; The ATLAS collaboration

    2018-01-01

    The large increase of pileup is one of the main experimental challenges for the HL-LHC physics program. A powerful new way to address this challenge is to exploit the time spread of the interactions to distinguish between collisions occurring very close in space but well separated in time. A High-Granularity Timing Detector, based on low gain avalanche detector technology, is proposed for the ATLAS Phase-II upgrade. Covering the pseudorapidity region between 2.4 and 4.0, with a timing resolution of 30 ps for minimum-ionizing particles, this device will significantly improve the performance in the forward region. High-precision timing greatly improves the track-to-vertex associ- ation, leading to a performance similar to that in the central region for both jet and lepton reconstruction, as well as the tagging of heavy-flavour jets. These improvements in object reconstruction performance translate into impor- tant sensitivity gains and enhance the reach of the HL-LHC physics program. In addition, the HGTD offer...

  20. X-ray bang-time and fusion reaction history at ~ps resolution using RadOptic detection

    Energy Technology Data Exchange (ETDEWEB)

    Vernon, S P; Lowry, M E; Baker, K L; Bennett, C V; Celeste, J R; Cerjan, C; Haynes, S; Hernandez, V J; Hsing, W W; London, R A; Moran, B; von Wittenau, A S; Steele, P T; Stewart, R E

    2012-05-01

    We report recent progress in the development of RadOptic detectors, radiation to optical converters, that rely upon x-ray absorption induced modulation of the optical refractive index of a semiconductor sensor medium to amplitude modulate an optical probe beam. The sensor temporal response is determined by the dynamics of the electron-hole pair creation and subsequent relaxation in the sensor medium. Response times of a few ps have been demonstrated in a series of experiments conducted at the LLNL Jupiter Laser Facility. This technology will enable x-ray bang-time and fusion burn-history measurements with {approx} ps resolution.

  1. A 16 channel high resolution (<11 ps RMS) Time-to-Digital Converter in a Field Programmable Gate Array

    International Nuclear Information System (INIS)

    Ugur, C; Bayer, E; Kurz, N; Traxler, M

    2012-01-01

    A 16-channel Time-to-Digital Converter (TDC) was implemented in a general purpose Field-Programmable Gate Array (FPGA). The fine time calculations are achieved by using the dedicated carry-chain lines. The coarse counter defines the coarse time stamp. In order to overcome the negative effects of temperature and power supply dependency bin-by-bin calibration is applied. The time interval measurements are done using 2 channels. The time resolution of channels are calculated for 1 clock cycle and a minimum of 10.3 ps RMS on two channels, yielding 7.3 ps RMS (10.3 ps/√2) on a single channel is achieved.

  2. Newmark local time stepping on high-performance computing architectures

    KAUST Repository

    Rietmann, Max

    2016-11-25

    In multi-scale complex media, finite element meshes often require areas of local refinement, creating small elements that can dramatically reduce the global time-step for wave-propagation problems due to the CFL condition. Local time stepping (LTS) algorithms allow an explicit time-stepping scheme to adapt the time-step to the element size, allowing near-optimal time-steps everywhere in the mesh. We develop an efficient multilevel LTS-Newmark scheme and implement it in a widely used continuous finite element seismic wave-propagation package. In particular, we extend the standard LTS formulation with adaptations to continuous finite element methods that can be implemented very efficiently with very strong element-size contrasts (more than 100×). Capable of running on large CPU and GPU clusters, we present both synthetic validation examples and large scale, realistic application examples to demonstrate the performance and applicability of the method and implementation on thousands of CPU cores and hundreds of GPUs.

  3. Performance of high-resolution position-sensitive detectors developed for storage-ring decay experiments

    International Nuclear Information System (INIS)

    Yamaguchi, T.; Suzaki, F.; Izumikawa, T.; Miyazawa, S.; Morimoto, K.; Suzuki, T.; Tokanai, F.; Furuki, H.; Ichihashi, N.; Ichikawa, C.; Kitagawa, A.; Kuboki, T.; Momota, S.; Nagae, D.; Nagashima, M.; Nakamura, Y.; Nishikiori, R.; Niwa, T.; Ohtsubo, T.; Ozawa, A.

    2013-01-01

    Highlights: • Position-sensitive detectors were developed for storage-ring decay spectroscopy. • Fiber scintillation and silicon strip detectors were tested with heavy ion beams. • A new fiber scintillation detector showed an excellent position resolution. • Position and energy detection by silicon strip detectors enable full identification. -- Abstract: As next generation spectroscopic tools, heavy-ion cooler storage rings will be a unique application of highly charged RI beam experiments. Decay spectroscopy of highly charged rare isotopes provides us important information relevant to the stellar conditions, such as for the s- and r-process nucleosynthesis. In-ring decay products of highly charged RI will be momentum-analyzed and reach a position-sensitive detector set-up located outside of the storage orbit. To realize such in-ring decay experiments, we have developed and tested two types of high-resolution position-sensitive detectors: silicon strips and scintillating fibers. The beam test experiments resulted in excellent position resolutions for both detectors, which will be available for future storage-ring experiments

  4. Mixed-time parallel evolution in multiple quantum NMR experiments: sensitivity and resolution enhancement in heteronuclear NMR

    International Nuclear Information System (INIS)

    Ying Jinfa; Chill, Jordan H.; Louis, John M.; Bax, Ad

    2007-01-01

    A new strategy is demonstrated that simultaneously enhances sensitivity and resolution in three- or higher-dimensional heteronuclear multiple quantum NMR experiments. The approach, referred to as mixed-time parallel evolution (MT-PARE), utilizes evolution of chemical shifts of the spins participating in the multiple quantum coherence in parallel, thereby reducing signal losses relative to sequential evolution. The signal in a given PARE dimension, t 1 , is of a non-decaying constant-time nature for a duration that depends on the length of t 2 , and vice versa, prior to the onset of conventional exponential decay. Line shape simulations for the 1 H- 15 N PARE indicate that this strategy significantly enhances both sensitivity and resolution in the indirect 1 H dimension, and that the unusual signal decay profile results in acceptable line shapes. Incorporation of the MT-PARE approach into a 3D HMQC-NOESY experiment for measurement of H N -H N NOEs in KcsA in SDS micelles at 50 o C was found to increase the experimental sensitivity by a factor of 1.7±0.3 with a concomitant resolution increase in the indirectly detected 1 H dimension. The method is also demonstrated for a situation in which homonuclear 13 C- 13 C decoupling is required while measuring weak H3'-2'OH NOEs in an RNA oligomer

  5. High resolution spectroscopy at FRM II: neutron resonance spin echo, back scattering and time-of-flight instrumentation

    International Nuclear Information System (INIS)

    Petry, W.

    2001-01-01

    The new German neutron source FRM II is equipped with a D 2 cold source placed in the maximum of the thermal flux in the D 2 O moderator. This cold source feeds six large neutron guides. Among others a neutron resonance spin echo (NRSE), a back scattering (BS) and a time-of-flight (TOF) spectrometer will be placed at end positions of theses guides. By detailed Monte-Carlo simulations each of the instruments is optimized for highest intensity without scarifying energy resolution. A polarized neutron guide in combination with a non magnetic wave-length selector provides high flux at the sample position of the NRSE instrument with typical spin-echo times of 30 ns at all accessible scattering angles. The BS instrument uses phase-space transformation to compress a large spread of incoming wave length to an intense monoenergetic but angular disperse beam at the sample. An intensity gain by a factor of four has been calculated without losses in energy resolution of <1 μeV (fwhm) when compared to conventional BS. The TOF spectrometer suppresses background from fast neutrons by a S-curved super-mirror guide and focusses a large incoming neutron beam onto a small sample volume, thereby increasing the flux at the sample position by a factor 3.2. Energy resolution of typical 30 μeV (fwhm) at a wave length of λ=5 A is achieved by extremely fast turning chopper discs made of carbon fiber. (author)

  6. Timing Performance of a MCP Photon Detector Read Out with Multi-Channel Electronics for the Torch System

    Science.gov (United States)

    Castillo García, L.; Fopma, J. M.; Forty, R.; Frei, C.; Gao, R.; Gys, T.; Harnew, N.; Piedigrossi, D.

    2014-06-01

    As part of the R&D phase of the (Time Of internally Reflected Cherenkov light) TORCH project, 8×8 pad micro-channel plate photon detectors are being characterized. Multichannel electronics based on fast amplifier discriminator and time digitization conversion ASICs are used to read out and time the charge signals from single photoelectrons. The MCP performance is investigated with a 20ps pulsed blue laser diode. A time resolution of 90ps is achieved. Timing properties are obtained at modest MCP gain, without time walk correction and no fine calibration of the time-to-digital converter circuit. The reference time is provided by a single-channel MCP photon detector coupled to a Constant Fraction Discriminator. Photoelectron detection efficiencies and back-scattering effect are discussed together with the laser source influence on the timing performance.

  7. Results from the NA62 Gigatracker Prototype: A Low-Mass and sub-ns Time Resolution Silicon Pixel Detector

    Science.gov (United States)

    Fiorini, M.; Rinella, G. Aglieri; Carassiti, V.; Ceccucci, A.; Gil, E. Cortina; Ramusino, A. Cotta; Dellacasa, G.; Garbolino, S.; Jarron, P.; Kaplon, J.; Kluge, A.; Marchetto, F.; Mapelli, A.; Martin, E.; Mazza, G.; Morel, M.; Noy, M.; Nuessle, G.; Petagna, P.; Petrucci, F.; Perktold, L.; Riedler, P.; Rivetti, A.; Statera, M.; Velghe, B.

    The Gigatracker (GTK) is a hybrid silicon pixel detector developed for NA62, the experiment aimed at studying ultra-rare kaon decays at the CERN SPS. Three GTK stations will provide precise momentum and angular measurements on every track of the high intensity NA62 hadron beam with a time-tagging resolution of 150 ps. Multiple scattering and hadronic interactions of beam particles in the GTK have to be minimized to keep background events at acceptable levels, hence the total material budget is fixed to 0.5% X0 per station. In addition the calculated fluence for 100 days of running is 2×1014 1 MeV neq/cm2, comparable to the one expected for the inner trackers of LHC detectors in 10 years of operation. These requirements pose challenges for the development of an efficient and low-mass cooling system, to be operated in vacuum, and on the thinning of read-out chips to 100 μm or less. The most challenging requirement is represented by the time resolution, which can be achieved by carefully compensating for the discriminator time-walk. For this purpose, two complementary read-out architectures have been designed and produced as small-scale prototypes: the first is based on the use of a Time-over-Threshold circuit followed by a TDC shared by a group of pixels, while the other uses a constant-fraction discriminator followed by an on-pixel TDC. The readout pixel ASICs are produced in 130 nm IBM CMOS technology and bump-bonded to 200 μm thick silicon sensors. The Gigatracker detector system is described with particular emphasis on recent experimental results obtained from laboratory and beam tests of prototype bump-bonded assemblies, which show a time resolution of less than 200 ps for single hits.

  8. Calibrating a hydraulic model using water levels derived from time series high-resolution Radarsat-2 synthetic aperture radar images and elevation data

    Science.gov (United States)

    Trudel, M.; Desrochers, N.; Leconte, R.

    2017-12-01

    Knowledge of water extent (WE) and level (WL) of rivers is necessary to calibrate and validate hydraulic models and thus to better simulate and forecast floods. Synthetic aperture radar (SAR) has demonstrated its potential for delineating water bodies, as backscattering of water is much lower than that of other natural surfaces. The ability of SAR to obtain information despite cloud cover makes it an interesting tool for temporal monitoring of water bodies. The delineation of WE combined with a high-resolution digital terrain model (DTM) allows extracting WL. However, most research using SAR data to calibrate hydraulic models has been carried out using one or two images. The objectives of this study is to use WL derived from time series high resolution Radarsat-2 SAR images for the calibration of a 1-D hydraulic model (HEC-RAS). Twenty high-resolution (5 m) Radarsat-2 images were acquired over a 40 km reach of the Athabasca River, in northern Alberta, Canada, between 2012 and 2016, covering both low and high flow regimes. A high-resolution (2m) DTM was generated combining information from LIDAR data and bathymetry acquired between 2008 and 2016 by boat surveying. The HEC-RAS model was implemented on the Athabasca River to simulate WL using cross-sections spaced by 100 m. An image histogram thresholding method was applied on each Radarsat-2 image to derive WE. WE were then compared against each cross-section to identify those were the slope of the banks is not too abrupt and therefore amenable to extract WL. 139 observations of WL at different locations along the river reach and with streamflow measurements were used to calibrate the HEC-RAS model. The RMSE between SAR-derived and simulated WL is under 0.35 m. Validation was performed using in situ observations of WL measured in 2008, 2012 and 2016. The RMSE between the simulated water levels calibrated with SAR images and in situ observations is less than 0.20 m. In addition, a critical success index (CSI) was

  9. Modular 125 ps resolution time interval digitizer for 10 MHz stop burst rates and 33 ms range

    International Nuclear Information System (INIS)

    Turko, B.

    1978-01-01

    A high resolution multiple stop time interval digitizer is described. It is capable of resolving stop burst rates of up to 10 MHz with an incremental resolution of 125 ps within a range of 33 ms. The digitizer consists of five CAMAC modules and uses a standard CAMAC crate and controller. All the functions and ranges are completely computer controlled. Any two subsequent stop pulses in a burst can be resolved within 100 ns due to a new dual interpolation technique employed. The accuracy is maintained by a high stability 125 MHz reference clock. Up to 131 stop events can be stored in a 48-bit, 10 MHz derandomizing storage register before the digitizer overflows. The experimental data are also given

  10. An Improved Method for Producing High Spatial-Resolution NDVI Time Series Datasets with Multi-Temporal MODIS NDVI Data and Landsat TM/ETM+ Images

    Directory of Open Access Journals (Sweden)

    Yuhan Rao

    2015-06-01

    Full Text Available Due to technical limitations, it is impossible to have high resolution in both spatial and temporal dimensions for current NDVI datasets. Therefore, several methods are developed to produce high resolution (spatial and temporal NDVI time-series datasets, which face some limitations including high computation loads and unreasonable assumptions. In this study, an unmixing-based method, NDVI Linear Mixing Growth Model (NDVI-LMGM, is proposed to achieve the goal of accurately and efficiently blending MODIS NDVI time-series data and multi-temporal Landsat TM/ETM+ images. This method firstly unmixes the NDVI temporal changes in MODIS time-series to different land cover types and then uses unmixed NDVI temporal changes to predict Landsat-like NDVI dataset. The test over a forest site shows high accuracy (average difference: −0.0070; average absolute difference: 0.0228; and average absolute relative difference: 4.02% and computation efficiency of NDVI-LMGM (31 seconds using a personal computer. Experiments over more complex landscape and long-term time-series demonstrated that NDVI-LMGM performs well in each stage of vegetation growing season and is robust in regions with contrasting spatial and spatial variations. Comparisons between NDVI-LMGM and current methods (i.e., Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM, Enhanced STARFM (ESTARFM and Weighted Linear Model (WLM show that NDVI-LMGM is more accurate and efficient than current methods. The proposed method will benefit land surface process research, which requires a dense NDVI time-series dataset with high spatial resolution.

  11. High-resolution time series of Pseudomonas aeruginosa gene expression and rhamnolipid secretion through growth curve synchronization

    Directory of Open Access Journals (Sweden)

    Xavier João B

    2011-06-01

    Full Text Available Abstract Background Online spectrophotometric measurements allow monitoring dynamic biological processes with high-time resolution. Contrastingly, numerous other methods require laborious treatment of samples and can only be carried out offline. Integrating both types of measurement would allow analyzing biological processes more comprehensively. A typical example of this problem is acquiring quantitative data on rhamnolipid secretion by the opportunistic pathogen Pseudomonas aeruginosa. P. aeruginosa cell growth can be measured by optical density (OD600 and gene expression can be measured using reporter fusions with a fluorescent protein, allowing high time resolution monitoring. However, measuring the secreted rhamnolipid biosurfactants requires laborious sample processing, which makes this an offline measurement. Results Here, we propose a method to integrate growth curve data with endpoint measurements of secreted metabolites that is inspired by a model of exponential cell growth. If serial diluting an inoculum gives reproducible time series shifted in time, then time series of endpoint measurements can be reconstructed using calculated time shifts between dilutions. We illustrate the method using measured rhamnolipid secretion by P. aeruginosa as endpoint measurements and we integrate these measurements with high-resolution growth curves measured by OD600 and expression of rhamnolipid synthesis genes monitored using a reporter fusion. Two-fold serial dilution allowed integrating rhamnolipid measurements at a ~0.4 h-1 frequency with high-time resolved data measured at a 6 h-1 frequency. We show how this simple method can be used in combination with mutants lacking specific genes in the rhamnolipid synthesis or quorum sensing regulation to acquire rich dynamic data on P. aeruginosa virulence regulation. Additionally, the linear relation between the ratio of inocula and the time-shift between curves produces high-precision measurements of

  12. Detection of Flooded Areas in a Time Series of High Resolution Synthetic Aperture Radar Images using Curvelet Transform and Unsupervised Classification.

    Science.gov (United States)

    Ajadi, O. A.; Meyer, F. J.; Liljedahl, A. K.

    2016-12-01

    Due to their weather and illumination independence and due to their large area coverage at high spatial resolution, Synthetic Aperture Radar (SAR) images have been recognized as a valuable data source for the mapping and tracking of flooding events. In order to optimize mapping accuracy, a SAR-based flood detection approach should provide the following features: (1) due to the recent increase of flood situations and the rising number of high-resolution SAR datasets that require rapid processing, the generation of flood maps should be accomplished automatically and with robust results; (2) due to the large spatial extent of many recent flooding events, a flood detection approach should be computationally efficient and transferable to different environmental conditions (surface cover; scene heterogeneity) and data types. Considering these requirements and to improve upon the current state-of-the-art, we propose an unsupervised flood detection approach that is based on a time-series analysis of multi-temporal SAR images. Due to the inclusion of geometric and radiometric terrain correction, our method automatically adapts to changing environmental parameters. To preserve the full resolution of the original SAR data while reducing the influence of Speckle on flood detection performance, we integrate several recent image processing developments in our approach: We use curvelet filtering methods to suppress noise while preserving most relevant image details. Similarly, we perform a multi-scale decomposition of the input images to generate image instances with varying resolutions and signal-to-noise ratios. Finally, to increase the robustness to false alarms, we incorporate time-series analysis techniques in our workflow: We first generate a redundant set of change probability maps from a stack of repeated SAR images and then invert this redundant set using least-square techniques to arrive at the most likely time series of surface change. To demonstrate the performance of

  13. The power of two-dimensional dwell-time analysis for model discrimination, temporal resolution, multichannel analysis and level detection.

    Science.gov (United States)

    Huth, Tobias; Schroeder, Indra; Hansen, Ulf-Peter

    2006-01-01

    Two-dimensional (2D) dwell-time analysis of time series of single-channel patch-clamp current was improved by employing a Hinkley detector for jump detection, introducing a genetic fit algorithm, replacing maximum likelihood by a least square criterion, averaging over a field of 9 or 25 bins in the 2D plane and normalizing per measuring time, not per events. Using simulated time series for the generation of the "theoretical" 2D histograms from assumed Markov models enabled the incor