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Sample records for robust background subtraction

  1. Background subtraction theory and practice

    CERN Document Server

    Elgammal, Ahmed

    2014-01-01

    Background subtraction is a widely used concept for detection of moving objects in videos. In the last two decades there has been a lot of development in designing algorithms for background subtraction, as well as wide use of these algorithms in various important applications, such as visual surveillance, sports video analysis, motion capture, etc. Various statistical approaches have been proposed to model scene backgrounds. The concept of background subtraction also has been extended to detect objects from videos captured from moving cameras. This book reviews the concept and practice of back

  2. Advanced Background Subtraction Applied to Aeroacoustic Wind Tunnel Testing

    Science.gov (United States)

    Bahr, Christopher J.; Horne, William C.

    2015-01-01

    An advanced form of background subtraction is presented and applied to aeroacoustic wind tunnel data. A variant of this method has seen use in other fields such as climatology and medical imaging. The technique, based on an eigenvalue decomposition of the background noise cross-spectral matrix, is robust against situations where isolated background auto-spectral levels are measured to be higher than levels of combined source and background signals. It also provides an alternate estimate of the cross-spectrum, which previously might have poor definition for low signal-to-noise ratio measurements. Simulated results indicate similar performance to conventional background subtraction when the subtracted spectra are weaker than the true contaminating background levels. Superior performance is observed when the subtracted spectra are stronger than the true contaminating background levels. Experimental results show limited success in recovering signal behavior for data where conventional background subtraction fails. They also demonstrate the new subtraction technique's ability to maintain a proper coherence relationship in the modified cross-spectral matrix. Beam-forming and de-convolution results indicate the method can successfully separate sources. Results also show a reduced need for the use of diagonal removal in phased array processing, at least for the limited data sets considered.

  3. Probabilistic Model-based Background Subtraction

    DEFF Research Database (Denmark)

    Krüger, Volker; Anderson, Jakob; Prehn, Thomas

    2005-01-01

    is the correlation between pixels. In this paper we introduce a model-based background subtraction approach which facilitates prior knowledge of pixel correlations for clearer and better results. Model knowledge is being learned from good training video data, the data is stored for fast access in a hierarchical...

  4. Background dose subtraction in personnel dosimetry

    International Nuclear Information System (INIS)

    Picazo, T.; Llorca, N.; Alabau, J.

    1997-01-01

    In this paper it is proposed to consider the mode of the frequency distribution of the low dose dosemeters from each clinic that uses X rays as the background environmental dose that should be subtracted from the personnel dosimetry to evaluate the doses due to practice. The problems and advantages of this indirect method to estimate the environmental background dose are discussed. The results for 60 towns are presented. (author)

  5. Moving object detection using background subtraction

    CERN Document Server

    Shaikh, Soharab Hossain; Chaki, Nabendu

    2014-01-01

    This Springer Brief presents a comprehensive survey of the existing methodologies of background subtraction methods. It presents a framework for quantitative performance evaluation of different approaches and summarizes the public databases available for research purposes. This well-known methodology has applications in moving object detection from video captured with a stationery camera, separating foreground and background objects and object classification and recognition. The authors identify common challenges faced by researchers including gradual or sudden illumination change, dynamic bac

  6. Diffraction, chopping, and background subtraction for LDR

    Science.gov (United States)

    Wright, Edward L.

    1988-01-01

    The Large Deployable Reflector (LDR) will be an extremely sensitive infrared telescope if the noise due to the photons in the large thermal background is the only limiting factor. For observations with a 3 arcsec aperture in a broadband at 100 micrometers, a 20-meter LDR will emit 10(exp 12) per second, while the photon noise limited sensitivity in a deep survey observation will be 3,000 photons per second. Thus the background subtraction has to work at the 1 part per billion level. Very small amounts of scattered or diffracted energy can be significant if they are modulated by the chopper. The results are presented for 1-D and 2-D diffraction calculations for the lightweight, low-cost LDR concept that uses an active chopping quaternary to correct the wavefront errors introduced by the primary. Fourier transforms were used to evaluate the diffraction of 1 mm waves through this system. Unbalanced signals due to dust and thermal gradients were also studied.

  7. IMPROVED BACKGROUND SUBTRACTION FOR THE SLOAN DIGITAL SKY SURVEY IMAGES

    International Nuclear Information System (INIS)

    Blanton, Michael R.; Kazin, Eyal; Muna, Demitri; Weaver, Benjamin A.; Price-Whelan, Adrian

    2011-01-01

    We describe a procedure for background subtracting Sloan Digital Sky Survey (SDSS) imaging that improves the resulting detection and photometry of large galaxies on the sky. Within each SDSS drift scan run, we mask out detected sources and then fit a smooth function to the variation of the sky background. This procedure has been applied to all SDSS-III Data Release 8 images, and the results are available as part of that data set. We have tested the effect of our background subtraction on the photometry of large galaxies by inserting fake galaxies into the raw pixels, reanalyzing the data, and measuring them after background subtraction. Our technique results in no size-dependent bias in galaxy fluxes up to half-light radii r 50 ∼ 100 arcsec; in contrast, for galaxies of that size the standard SDSS photometric catalog underestimates fluxes by about 1.5 mag. Our results represent a substantial improvement over the standard SDSS catalog results and should form the basis of any analysis of nearby galaxies using the SDSS imaging data.

  8. Background subtraction system for pulsed neutron logging of earth boreholes

    International Nuclear Information System (INIS)

    Hopkinson, E.C.

    1977-01-01

    A neutron generator in well logging instrument is pulsed 100 times having a time between pulses of 1400 microseconds. This is followed by an off period of four cycles wherein 2800 microseconds is allowed for capture radiation to decay to an insignificant level and the remaining 2800 microseconds is used to measure background radiation. This results in the neutron source being disabled four pulses after every hundred pulses of operation, or approximately a 4 percent loss of neutron output. A first detector gate is open from 400 to 680 microseconds and a second detector gate is open from 700 to 980 microseconds. During the 100 cycles, each of the gates is thus open for 280 microseconds times 100 for a total of 28,000 microseconds. By scaling the gate count rate by a factor of 10, the background is subtracted directly

  9. A multiple regression analysis for accurate background subtraction in 99Tcm-DTPA renography

    International Nuclear Information System (INIS)

    Middleton, G.W.; Thomson, W.H.; Davies, I.H.; Morgan, A.

    1989-01-01

    A technique for accurate background subtraction in 99 Tc m -DTPA renography is described. The technique is based on a multiple regression analysis of the renal curves and separate heart and soft tissue curves which together represent background activity. It is compared, in over 100 renograms, with a previously described linear regression technique. Results show that the method provides accurate background subtraction, even in very poorly functioning kidneys, thus enabling relative renal filtration and excretion to be accurately estimated. (author)

  10. Quantitative analysis of planar technetium-99m-sestamibi myocardial perfusion images using modified background subtraction

    International Nuclear Information System (INIS)

    Koster, K.; Wackers, F.J.; Mattera, J.A.; Fetterman, R.C.

    1990-01-01

    Standard interpolative background subtraction, as used for thallium-201 ( 201 Tl), may create artifacts when applied to planar technetium-99m-Sestamibi ( 99m Tc-Sestamibi) images, apparently because of the oversubtraction of relatively high extra-cardiac activity. A modified background subtraction algorithm was developed and compared to standard background subtraction in 16 patients who had both exercise-delayed 201 Tl and exercise-rest 99m Tc-Sestamibi imaging. Furthermore, a new normal data base was generated. Normal 99m Tc-Sestamibi distribution was slightly different compared to 201 Tl. Using standard background subtraction, mean defect reversibility was significantly underestimated by 99m Tc-Sestamibi compared to 201 Tl (2.8 +/- 4.9 versus -1.8 +/- 8.4, p less than 0.05). Using the modified background subtraction, mean defect reversibility on 201 Tl and 99m Tc-Sestamibi images was comparable (2.8 +/- 4.9 versus 1.7 +/- 5.2, p = NS). We conclude, that for quantification of 99m Tc-Sestamibi images a new normal data base, as well as a modification of the interpolative background subtraction method should be employed to obtain quantitative results comparable to those with 201 Tl

  11. Hand Gesture Recognition Using Modified 1$ and Background Subtraction Algorithms

    Directory of Open Access Journals (Sweden)

    Hazem Khaled

    2015-01-01

    Full Text Available Computers and computerized machines have tremendously penetrated all aspects of our lives. This raises the importance of Human-Computer Interface (HCI. The common HCI techniques still rely on simple devices such as keyboard, mice, and joysticks, which are not enough to convoy the latest technology. Hand gesture has become one of the most important attractive alternatives to existing traditional HCI techniques. This paper proposes a new hand gesture detection system for Human-Computer Interaction using real-time video streaming. This is achieved by removing the background using average background algorithm and the 1$ algorithm for hand’s template matching. Then every hand gesture is translated to commands that can be used to control robot movements. The simulation results show that the proposed algorithm can achieve high detection rate and small recognition time under different light changes, scales, rotation, and background.

  12. Background subtraction system for pulsed neutron logging of earth boreholes

    International Nuclear Information System (INIS)

    Hertzog, R.C.

    1983-01-01

    The invention provides a method for determining the characteristics of earth formations surrounding a well borehole comprising the steps of: repetitively irradiating the earth formations surrounding the well bore with relatively short duration pulses of high energy neutrons; detecting during each pulse of high energy neutrons, gamma radiation due to the inelastic scattering of neutrons by materials comprising the earth formations surrounding the borehole and providing information representative thereof; detecting immediately following each such pulse of high energy neutrons, background gamma radiation due to thermal neutron capture and providing information representative thereof; and correcting the inelastic gamma representative information to compensate for said background representative information

  13. Comparison of two interpolative background subtraction methods using phantom and clinical data

    International Nuclear Information System (INIS)

    Houston, A.S.; Sampson, W.F.D.

    1989-01-01

    Two interpolative background subtraction methods used in scintigraphy are tested using both phantom and clinical data. Cauchy integral subtraction was found to be relatively free of artefacts but required more computing time than bilinear interpolation. Both methods may be used with reasonable confidence for the quantification of relative measurements such as left ventricular ejection fraction and myocardial perfusion index but should be avoided if at all possible in the quantification of absolute measurements such as glomerular filtration rate. (author)

  14. Data Series Subtraction with Unknown and Unmodeled Background Noise

    Science.gov (United States)

    Vitale, Stefano; Congedo, Giuseppe; Dolesi, Rita; Ferroni, Valerio; Hueller, Mauro; Vetrugno, Daniele; Weber, William Joseph; Audley, Heather; Danzmann, Karsten; Diepholz, Ingo; hide

    2014-01-01

    LISA Pathfinder (LPF), the precursor mission to a gravitational wave observatory of the European Space Agency, will measure the degree to which two test masses can be put into free fall, aiming to demonstrate a suppression of disturbance forces corresponding to a residual relative acceleration with a power spectral density (PSD) below (30 fm/sq s/Hz)(sup 2) around 1 mHz. In LPF data analysis, the disturbance forces are obtained as the difference between the acceleration data and a linear combination of other measured data series. In many circumstances, the coefficients for this linear combination are obtained by fitting these data series to the acceleration, and the disturbance forces appear then as the data series of the residuals of the fit. Thus the background noise or, more precisely, its PSD, whose knowledge is needed to build up the likelihood function in ordinary maximum likelihood fitting, is here unknown, and its estimate constitutes instead one of the goals of the fit. In this paper we present a fitting method that does not require the knowledge of the PSD of the background noise. The method is based on the analytical marginalization of the posterior parameter probability density with respect to the background noise PSD, and returns an estimate both for the fitting parameters and for the PSD. We show that both these estimates are unbiased, and that, when using averaged Welchs periodograms for the residuals, the estimate of the PSD is consistent, as its error tends to zero with the inverse square root of the number of averaged periodograms. Additionally, we find that the method is equivalent to some implementations of iteratively reweighted least-squares fitting. We have tested the method both on simulated data of known PSD and on data from several experiments performed with the LISA Pathfinder end-to-end mission simulator.

  15. A single injection technique for subtraction of blood background in 131I-hippuran renograms

    International Nuclear Information System (INIS)

    Rutland, M.D.

    1979-01-01

    A method of subtracting blood background during probe-renography is presented which does not require a prior injection of RIHSA and which produces results approximately 11% higher than the RIHSA method. The new method treats the renogram up to two-and-a-half minutes as a combination of a fraction of the blood curve and a fraction of the integral of the blood curve. Analysis of the data, using either a computer or a programmed calculator, enables these two fractions to be calculated, hence producing the 'background subtraction factor' and the 'uptake constant'. (author)

  16. Segmentation of Moving Object Using Background Subtraction Method in Complex Environments

    Directory of Open Access Journals (Sweden)

    S. Kumar

    2016-06-01

    Full Text Available Background subtraction is an extensively used approach to localize the moving object in a video sequence. However, detecting an object under the spatiotemporal behavior of background such as rippling of water, moving curtain and illumination change or low resolution is not a straightforward task. To deal with the above-mentioned problem, we address a background maintenance scheme based on the updating of background pixels by estimating the current spatial variance along the temporal line. The work is focused to immune the variation of local motion in the background. Finally, the most suitable label assignment to the motion field is estimated and optimized by using iterated conditional mode (ICM under a Markovian framework. Performance evaluation and comparisons with the other well-known background subtraction methods show that the proposed method is unaffected by the problem of aperture distortion, ghost image, and high frequency noise.

  17. A method for subtraction of the extrarenal 'background' in dynamic 131I-hippurate renoscintigraphy

    International Nuclear Information System (INIS)

    Mlodkowska, E.; Liniecki, J.; Surma, M.

    1979-01-01

    Using a Toshiba GC-401 gamma camera with MDS computer Trinary a new method was developed for subtracting the extrarenal (extracanalicular) 'background' from the count rate recorded over the kidneys after intravenous administration of 131 I-hippurate. Mean subtraction factors of the 'blood' activity curve were calculated from a study of 27 patients who were given 51 Cr-HSA for purposes of conventional renography with 'background' subtraction. The values of the mean subtraction factors anti Fsub(R,L) for the right and left kidney, by which a blood count rate should be multiplied amounted to 0.86 +- 0.12 and 0.79 +- 0.13, respectively. A comparison of the coefficients of variation of the pure renal signal when mean vs. individually determined subtraction factors were used, and the verification of the method in unilaterally nephrectomized patients have demonstrated that determination of the factors, anti Fsub(R,L), for each patient individually is not required and sufficient precision can be obtained by using the method and factors reported in this study. (orig.) [de

  18. The Pedestrian Detection Method Using an Extension Background Subtraction about the Driving Safety Support Systems

    Science.gov (United States)

    Muranaka, Noriaki; Date, Kei; Tokumaru, Masataka; Imanishi, Shigeru

    In recent years, the traffic accident occurs frequently with explosion of traffic density. Therefore, we think that the safe and comfortable transportation system to defend the pedestrian who is the traffic weak is necessary. First, we detect and recognize the pedestrian (the crossing person) by the image processing. Next, we inform all the drivers of the right or left turn that the pedestrian exists by the sound and the image and so on. By prompting a driver to do safe driving in this way, the accident to the pedestrian can decrease. In this paper, we are using a background subtraction method for the movement detection of the movement object. In the background subtraction method, the update method in the background was important, and as for the conventional way, the threshold values of the subtraction processing and background update were identical. That is, the mixing rate of the input image and the background image of the background update was a fixation value, and the fine tuning which corresponded to the environment change of the weather was difficult. Therefore, we propose the update method of the background image that the estimated mistake is difficult to be amplified. We experiment and examines in the comparison about five cases of sunshine, cloudy, evening, rain, sunlight change, except night. This technique can set separately the threshold values of the subtraction processing and background update processing which suited the environmental condition of the weather and so on. Therefore, the fine tuning becomes possible freely in the mixing rate of the input image and the background image of the background update. Because the setting of the parameter which suited an environmental condition becomes important to minimize mistaking percentage, we examine about the setting of a parameter.

  19. Visualisation of bony and vascular structures via digital subtraction images upon the amount of anatomic background

    International Nuclear Information System (INIS)

    Hinz, A.; Scholz, A.; Zwicker, C.

    1992-01-01

    We examined the loss of contrast leaving a part of the anatomic background in digital subtraction angiography by visual analysis and densitometry. We observed a greater loss of the quality at the representation of the bone below than above an amount of anatomic background of 60%. The loss of quality at the representation of the vessels decreases more above than below an anatomical background of 45%. We think that, depending on the clinical problem, an anatomical background between 15 and 30% should be left. (orig.) [de

  20. PCA-based approach for subtracting thermal background emission in high-contrast imaging data

    Science.gov (United States)

    Hunziker, S.; Quanz, S. P.; Amara, A.; Meyer, M. R.

    2018-03-01

    Aims.Ground-based observations at thermal infrared wavelengths suffer from large background radiation due to the sky, telescope and warm surfaces in the instrument. This significantly limits the sensitivity of ground-based observations at wavelengths longer than 3 μm. The main purpose of this work is to analyse this background emission in infrared high-contrast imaging data as illustrative of the problem, show how it can be modelled and subtracted and demonstrate that it can improve the detection of faint sources, such as exoplanets. Methods: We used principal component analysis (PCA) to model and subtract the thermal background emission in three archival high-contrast angular differential imaging datasets in the M' and L' filter. We used an M' dataset of β Pic to describe in detail how the algorithm works and explain how it can be applied. The results of the background subtraction are compared to the results from a conventional mean background subtraction scheme applied to the same dataset. Finally, both methods for background subtraction are compared by performing complete data reductions. We analysed the results from the M' dataset of HD 100546 only qualitatively. For the M' band dataset of β Pic and the L' band dataset of HD 169142, which was obtained with an angular groove phase mask vortex vector coronagraph, we also calculated and analysed the achieved signal-to-noise ratio (S/N). Results: We show that applying PCA is an effective way to remove spatially and temporarily varying thermal background emission down to close to the background limit. The procedure also proves to be very successful at reconstructing the background that is hidden behind the point spread function. In the complete data reductions, we find at least qualitative improvements for HD 100546 and HD 169142, however, we fail to find a significant increase in S/N of β Pic b. We discuss these findings and argue that in particular datasets with strongly varying observing conditions or

  1. An analysis of the influence of background subtraction and quenching on jet observables in heavy-ion collisions

    CERN Document Server

    Apolinario, Liliana; Cunqueiro, Leticia

    2013-01-01

    Subtraction of the large background in reconstruction is a key ingredient in jet studies in high-energy heavy-ion collisions at RHIC and the LHC. Here we address the question to which extent the most commonly used subtraction techniques are able to eliminate the effects of the background on the most commonly discussed observables at present: single inclusive jet distributions, dijet asymmetry and azimuthal distributions. We consider two different background subtraction methods, an area-based one implemented through the FastJet pack- age and a pedestal subtraction method, that resemble the ones used by the experimental collaborations at the LHC. We also analyze different ways of defining the optimal parame- ters in the second method. We use a toy model that easily allows variations of the background characteristics: average background level and fluctuations and azimuthal structure, but cross- checks are also done with a Monte Carlo simulator. Furthermore, we consider the influence of quenching using Q-PYTHIA o...

  2. A System based on Adaptive Background Subtraction Approach for Moving Object Detection and Tracking in Videos

    Directory of Open Access Journals (Sweden)

    Bahadır KARASULU

    2013-04-01

    Full Text Available Video surveillance systems are based on video and image processing research areas in the scope of computer science. Video processing covers various methods which are used to browse the changes in existing scene for specific video. Nowadays, video processing is one of the important areas of computer science. Two-dimensional videos are used to apply various segmentation and object detection and tracking processes which exists in multimedia content-based indexing, information retrieval, visual and distributed cross-camera surveillance systems, people tracking, traffic tracking and similar applications. Background subtraction (BS approach is a frequently used method for moving object detection and tracking. In the literature, there exist similar methods for this issue. In this research study, it is proposed to provide a more efficient method which is an addition to existing methods. According to model which is produced by using adaptive background subtraction (ABS, an object detection and tracking system’s software is implemented in computer environment. The performance of developed system is tested via experimental works with related video datasets. The experimental results and discussion are given in the study

  3. Determination of endogenous inflammation-related lipid mediators in ischemic stroke rats using background subtracting calibration curves by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Yang, Yang; Zhong, Qisheng; Mo, Canlong; Zhang, Hao; Zhou, Ting; Tan, Wen

    2017-11-01

    Accurate and reliable quantification of endogenous lipid mediators in complex biological samples is a daunting challenge. In this study, a robust and direct endogenous quantitative method using background subtracting calibration curves by liquid chromatography-tandem mass spectrometry was first developed for the determination of endogenous lipid mediators in ischemic stroke rats. Absolute quantification without surrogate matrix could be achieved by using background subtracting calibration curves, which were corrected and verified from standard curves constructed on original matrix. The recoveries of this method were in the range of 50.3-98.3%, the precision with the relative standard deviation was less than 13.8%, and the accuracy with the relative error was within ± 15.0%. In addition, background subtracting calibration curves were further verified by validation factors ranging from 90.3 to 110.9%. This validated method has been successfully applied to the analysis of seven endogenous inflammation-related lipid mediators in the brain tissues of ischemic stroke rats. The results indicated that prostaglandins as inflammatory factors and some lipid mediators with neuroprotective effects increased apparently (p endogenous compounds in the complex biological samples. Graphical abstract The analysis procedure of determining endogenous inflammation-related lipid mediators using BSCC by LC-MS/MS.

  4. FPGA implementation for real-time background subtraction based on Horprasert model.

    Science.gov (United States)

    Rodriguez-Gomez, Rafael; Fernandez-Sanchez, Enrique J; Diaz, Javier; Ros, Eduardo

    2012-01-01

    Background subtraction is considered the first processing stage in video surveillance systems, and consists of determining objects in movement in a scene captured by a static camera. It is an intensive task with a high computational cost. This work proposes an embedded novel architecture on FPGA which is able to extract the background on resource-limited environments and offers low degradation (produced because of the hardware-friendly model modification). In addition, the original model is extended in order to detect shadows and improve the quality of the segmentation of the moving objects. We have analyzed the resource consumption and performance in Spartan3 Xilinx FPGAs and compared to others works available on the literature, showing that the current architecture is a good trade-off in terms of accuracy, performance and resources utilization. With less than a 65% of the resources utilization of a XC3SD3400 Spartan-3A low-cost family FPGA, the system achieves a frequency of 66.5 MHz reaching 32.8 fps with resolution 1,024 × 1,024 pixels, and an estimated power consumption of 5.76 W.

  5. FPGA Implementation for Real-Time Background Subtraction Based on Horprasert Model

    Directory of Open Access Journals (Sweden)

    Eduardo Ros

    2012-01-01

    Full Text Available Background subtraction is considered the first processing stage in video surveillance systems, and consists of determining objects in movement in a scene captured by a static camera. It is an intensive task with a high computational cost. This work proposes an embedded novel architecture on FPGA which is able to extract the background on resource-limited environments and offers low degradation (produced because of the hardware-friendly model modification. In addition, the original model is extended in order to detect shadows and improve the quality of the segmentation of the moving objects. We have analyzed the resource consumption and performance in Spartan3 Xilinx FPGAs and compared to others works available on the literature, showing that the current architecture is a good trade-off in terms of accuracy, performance and resources utilization. With less than a 65% of the resources utilization of a XC3SD3400 Spartan-3A low-cost family FPGA, the system achieves a frequency of 66.5 MHz reaching 32.8 fps with resolution 1,024 x 1,024 pixels, and an estimated power consumption of 5.76 W.

  6. Calculating exclusion limits for weakly interacting massive particle direct detection experiments without background subtraction

    International Nuclear Information System (INIS)

    Green, Anne M.

    2002-01-01

    Competitive limits on the weakly interacting massive particle (WIMP) spin-independent scattering cross section are currently being produced by 76 Ge detectors originally designed to search for neutrinoless double beta decay, such as the Heidelberg-Moscow and IGEX experiments. In the absence of background subtraction, limits on the WIMP interaction cross section are set by calculating the upper confidence limit on the theoretical event rate, given the observed event rate. The standard analysis technique involves calculating the 90% upper confidence limit on the number of events in each bin, and excluding any set of parameters (WIMP mass and cross section) which produces a theoretical event rate for any bin which exceeds the 90% upper confidence limit on the event rate for that bin. We show that, if there is more than one energy bin, this produces exclusion limits that are actually at a lower degree of confidence than 90%, and are hence erroneously tight. We formulate criteria which produce true 90% confidence exclusion limits in these circumstances, including calculating the individual bin confidence limit for which the overall probability that no bins exceed this confidence limit is 90% and calculating the 90% minimum confidence limit on the number of bins which exceed their individual bin 90% confidence limits. We then compare the limits on the WIMP cross section produced by these criteria with those found using the standard technique, using data from the Heidelberg-Moscow and IGEX experiments

  7. REAL TIME TRACKING OBYEK BERGERAK DENGAN WEBCAM BERBASIS WARNA DENGAN METODE BACKGROUND SUBTRACTION

    Directory of Open Access Journals (Sweden)

    Aris Tri Jaka Harjanta

    2017-07-01

    Full Text Available Proses tracking obyek pada real time  video adalah salah satu topik yang penting dalam kajian suveillance system (Dhananjaya, Rama, and Thimmaiah 2015. deteksi dan ekstraksi informasi serta pelacakan obyek atau benda bergerak adalah sebagai salah satu bentuk aplikasi dari computer vision. Beberapa aplikasi yang memanfaatkan metode tracking object atau benda bergerak antara lain adalah UAV (Unmanned Aerial Vehicle surveillance atau lebih dikenal dengan mesin/kendaraan tak berawak, Indoor Monitoring system adalah sistem monitoring keadaan dalam ruangan, serta memonitor trafik lalu lintas yang dapat mengamati pergerakan semua benda dalam keadaan real time. Tracking obyek dalam keadaan real time banyak hal yang perlu diperhatikan dan perlu diperhitungkan dimana semua parameter dan noise atau gangguan object di sekitarnya yang tidak perlu kita amati namun berada dalam satu bagian bersama obyek yang kita amati. Dalam penelitian ini metode yang akan digunakan adalah background subtraction untuk pendeteksian serta tracking obyek dan benda bergerak secara real time berbasis warna dengan memanfaatkan kamera webcam dan menggunakan pustaka opensource OpenCv.

  8. Wind profiling for a coherent wind Doppler lidar by an auto-adaptive background subtraction approach.

    Science.gov (United States)

    Wu, Yanwei; Guo, Pan; Chen, Siying; Chen, He; Zhang, Yinchao

    2017-04-01

    Auto-adaptive background subtraction (AABS) is proposed as a denoising method for data processing of the coherent Doppler lidar (CDL). The method is proposed specifically for a low-signal-to-noise-ratio regime, in which the drifting power spectral density of CDL data occurs. Unlike the periodogram maximum (PM) and adaptive iteratively reweighted penalized least squares (airPLS), the proposed method presents reliable peaks and is thus advantageous in identifying peak locations. According to the analysis results of simulated and actually measured data, the proposed method outperforms the airPLS method and the PM algorithm in the furthest detectable range. The proposed method improves the detection range approximately up to 16.7% and 40% when compared to the airPLS method and the PM method, respectively. It also has smaller mean wind velocity and standard error values than the airPLS and PM methods. The AABS approach improves the quality of Doppler shift estimates and can be applied to obtain the whole wind profiling by the CDL.

  9. Robust estimation of the noise variance from background MR data

    NARCIS (Netherlands)

    Sijbers, J.; Den Dekker, A.J.; Poot, D.; Bos, R.; Verhoye, M.; Van Camp, N.; Van der Linden, A.

    2006-01-01

    In the literature, many methods are available for estimation of the variance of the noise in magnetic resonance (MR) images. A commonly used method, based on the maximum of the background mode of the histogram, is revisited and a new, robust, and easy to use method is presented based on maximum

  10. Boundary layer noise subtraction in hydrodynamic tunnel using robust principal component analysis.

    Science.gov (United States)

    Amailland, Sylvain; Thomas, Jean-Hugh; Pézerat, Charles; Boucheron, Romuald

    2018-04-01

    The acoustic study of propellers in a hydrodynamic tunnel is of paramount importance during the design process, but can involve significant difficulties due to the boundary layer noise (BLN). Indeed, advanced denoising methods are needed to recover the acoustic signal in case of poor signal-to-noise ratio. The technique proposed in this paper is based on the decomposition of the wall-pressure cross-spectral matrix (CSM) by taking advantage of both the low-rank property of the acoustic CSM and the sparse property of the BLN CSM. Thus, the algorithm belongs to the class of robust principal component analysis (RPCA), which derives from the widely used principal component analysis. If the BLN is spatially decorrelated, the proposed RPCA algorithm can blindly recover the acoustical signals even for negative signal-to-noise ratio. Unfortunately, in a realistic case, acoustic signals recorded in a hydrodynamic tunnel show that the noise may be partially correlated. A prewhitening strategy is then considered in order to take into account the spatially coherent background noise. Numerical simulations and experimental results show an improvement in terms of BLN reduction in the large hydrodynamic tunnel. The effectiveness of the denoising method is also investigated in the context of acoustic source localization.

  11. Research on the algorithm of infrared target detection based on the frame difference and background subtraction method

    Science.gov (United States)

    Liu, Yun; Zhao, Yuejin; Liu, Ming; Dong, Liquan; Hui, Mei; Liu, Xiaohua; Wu, Yijian

    2015-09-01

    As an important branch of infrared imaging technology, infrared target tracking and detection has a very important scientific value and a wide range of applications in both military and civilian areas. For the infrared image which is characterized by low SNR and serious disturbance of background noise, an innovative and effective target detection algorithm is proposed in this paper, according to the correlation of moving target frame-to-frame and the irrelevance of noise in sequential images based on OpenCV. Firstly, since the temporal differencing and background subtraction are very complementary, we use a combined detection method of frame difference and background subtraction which is based on adaptive background updating. Results indicate that it is simple and can extract the foreground moving target from the video sequence stably. For the background updating mechanism continuously updating each pixel, we can detect the infrared moving target more accurately. It paves the way for eventually realizing real-time infrared target detection and tracking, when transplanting the algorithms on OpenCV to the DSP platform. Afterwards, we use the optimal thresholding arithmetic to segment image. It transforms the gray images to black-white images in order to provide a better condition for the image sequences detection. Finally, according to the relevance of moving objects between different frames and mathematical morphology processing, we can eliminate noise, decrease the area, and smooth region boundaries. Experimental results proves that our algorithm precisely achieve the purpose of rapid detection of small infrared target.

  12. Adjustment of geochemical background by robust multivariate statistics

    Science.gov (United States)

    Zhou, D.

    1985-01-01

    Conventional analyses of exploration geochemical data assume that the background is a constant or slowly changing value, equivalent to a plane or a smoothly curved surface. However, it is better to regard the geochemical background as a rugged surface, varying with changes in geology and environment. This rugged surface can be estimated from observed geological, geochemical and environmental properties by using multivariate statistics. A method of background adjustment was developed and applied to groundwater and stream sediment reconnaissance data collected from the Hot Springs Quadrangle, South Dakota, as part of the National Uranium Resource Evaluation (NURE) program. Source-rock lithology appears to be a dominant factor controlling the chemical composition of groundwater or stream sediments. The most efficacious adjustment procedure is to regress uranium concentration on selected geochemical and environmental variables for each lithologic unit, and then to delineate anomalies by a common threshold set as a multiple of the standard deviation of the combined residuals. Robust versions of regression and RQ-mode principal components analysis techniques were used rather than ordinary techniques to guard against distortion caused by outliers Anomalies delineated by this background adjustment procedure correspond with uranium prospects much better than do anomalies delineated by conventional procedures. The procedure should be applicable to geochemical exploration at different scales for other metals. ?? 1985.

  13. Robustness of cosmic neutrino background detection in the cosmic microwave background

    Energy Technology Data Exchange (ETDEWEB)

    Audren, Benjamin [Institut de Théorie des Phénomènes Physiques, École Polytechnique Fédérale de Lausanne, CH-1015, Lausanne (Switzerland); Bellini, Emilio; Cuesta, Antonio J.; Verde, Licia [Institut de Ciències del Cosmos, Universitat de Barcelona, IEEC-UB, Martí i Franquès 1, E08028 Barcelona (Spain); Gontcho, Satya Gontcho A; Pérez-Ràfols, Ignasi [Dept. d' Astronomia i Meteorologia, Institut de Ciències del Cosmos, Universitat de Barcelona, IEEC-UB, Martí i Franquès 1, E08028 Barcelona (Spain); Lesgourgues, Julien [CERN, Theory Division, CH-1211 Geneva 23 (Switzerland); Niro, Viviana [Departamento de Física Teórica, Universidad Autónoma de Madrid and Instituto de Física Teórica UAM/CSIC, Calle Nicolás Cabrera 13-15, Cantoblanco, E-28049 Madrid (Spain); Pellejero-Ibanez, Marcos; Tramonte, Denis [Instituto de Astrofísica de Canarias (IAC), C/Vía Láctea s/n, E-38200, La Laguna, Tenerife (Spain); Poulin, Vivian [LAPTh, Université de Savoie, CNRS, B.P.110, Annecy-le-Vieux F-74941 (France); Tram, Thomas, E-mail: emilio.bellini@icc.ub.edu [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX (United Kingdom)

    2015-03-01

    The existence of a cosmic neutrino background can be probed indirectly by CMB experiments, not only by measuring the background density of radiation in the universe, but also by searching for the typical signatures of the fluctuations of free-streaming species in the temperature and polarisation power spectrum. Previous studies have already proposed a rather generic parametrisation of these fluctuations, that could help to discriminate between the signature of ordinary free-streaming neutrinos, or of more exotic dark radiation models. Current data are compatible with standard values of these parameters, which seems to bring further evidence for the existence of a cosmic neutrino background. In this work, we investigate the robustness of this conclusion under various assumptions. We generalise the definition of an effective sound speed and viscosity speed to the case of massive neutrinos or other dark radiation components experiencing a non-relativistic transition. We show that current bounds on these effective parameters do not vary significantly when considering an arbitrary value of the particle mass, or extended cosmological models with a free effective neutrino number, dynamical dark energy or a running of the primordial spectrum tilt. We conclude that it is possible to make a robust statement about the detection of the cosmic neutrino background by CMB experiments.

  14. M-BAND IMAGING OF THE HR 8799 PLANETARY SYSTEM USING AN INNOVATIVE LOCI-BASED BACKGROUND SUBTRACTION TECHNIQUE

    International Nuclear Information System (INIS)

    Galicher, Raphael; Marois, Christian; Macintosh, Bruce; Konopacky, Quinn; Barman, Travis

    2011-01-01

    Multi-wavelength observations/spectroscopy of exoplanetary atmospheres are the basis of the emerging exciting field of comparative exoplanetology. The HR 8799 planetary system is an ideal laboratory to study our current knowledge gap between massive field brown dwarfs and the cold 5 Gyr old solar system planets. The HR 8799 planets have so far been imaged at J- to L-band, with only upper limits available at M-band. We present here deep high-contrast Keck II adaptive optics M-band observations that show the imaging detection of three of the four currently known HR 8799 planets. Such detections were made possible due to the development of an innovative LOCI-based background subtraction scheme that is three times more efficient than a classical median background subtraction for Keck II AO data, representing a gain in telescope time of up to a factor of nine. These M-band detections extend the broadband photometric coverage out to ∼5 μm and provide access to the strong CO fundamental absorption band at 4.5 μm. The new M-band photometry shows that the HR 8799 planets are located near the L/T-type dwarf transition, similar to what was found by other studies. We also confirm that the best atmospheric fits are consistent with low surface gravity, dusty, and non-equilibrium CO/CH 4 chemistry models.

  15. Robustness of cosmic neutrino background detection in the cosmic microwave background

    CERN Document Server

    Audren, Benjamin; Cuesta, Antonio J; Gontcho, Satya Gontcho A; Lesgourgues, Julien; Niro, Viviana; Pellejero-Ibanez, Marcos; Pérez-Ràfols, Ignasi; Poulin, Vivian; Tram, Thomas; Tramonte, Denis; Verde, Licia

    2015-01-01

    The existence of a cosmic neutrino background can be probed indirectly by CMB experiments, not only by measuring the background density of radiation in the universe, but also by searching for the typical signatures of the fluctuations of free-streaming species in the temperature and polarisation power spectrum. Previous studies have already proposed a rather generic parametrisation of these fluctuations, that could help to discriminate between the signature of ordinary free-streaming neutrinos, or of more exotic dark radiation models. Current data are compatible with standard values of these parameters, which seems to bring further evidence for the existence of a cosmic neutrino background. In this work, we investigate the robustness of this conclusion under various assumptions. We generalise the definition of an effective sound speed and viscosity speed to the case of massive neutrinos or other dark radiation components experiencing a non-relativistic transition. We show that current bounds on these effectiv...

  16. A novel approach to background subtraction in contrast-enhanced dual-energy digital mammography with commercially available mammography devices: Noise minimization

    International Nuclear Information System (INIS)

    Contillo, Adriano; Di Domenico, Giovanni; Cardarelli, Paolo; Gambaccini, Mauro; Taibi, Angelo

    2016-01-01

    Purpose: Dual-energy image subtraction represents a useful tool to improve the detectability of small lesions, especially in dense breasts. A feature it shares with all x-ray imaging techniques is the appearance of fluctuations in the texture of the background, which can obscure the visibility of interesting details. The aim of the work is to investigate the main noise sources, in order to create a better performing subtraction mechanism. In particular, the structural noise cancellation was achieved by means of a suitable extension of the dual-energy algorithm. Methods: The effect of the cancellation procedure was tested on an analytical simulation of a target with varying structural composition. Subsequently, the subtraction algorithm was also applied to a set of actual radiographs of a breast phantom exhibiting a nonuniform background pattern. The background power spectra of the outcomes were computed and compared to the ones obtained from a standard subtraction algorithm. Results: The comparison between the standard and the proposed cancellations showed an overall suppression of the magnitudes of the spectra, as well as a flattening of the frequency dependence of the structural component of the noise. Conclusions: The proposed subtraction procedure provides an effective cancellation of the residual background fluctuations. When combined with the polychromatic correction already described in a companion publication, it results in a high performing dual-energy subtraction scheme for commercial mammography units.

  17. A novel approach to background subtraction in contrast-enhanced dual-energy digital mammography with commercially available mammography devices: Noise minimization

    Energy Technology Data Exchange (ETDEWEB)

    Contillo, Adriano, E-mail: contillo@fe.infn.it; Di Domenico, Giovanni; Cardarelli, Paolo; Gambaccini, Mauro; Taibi, Angelo [Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Via Saragat 1, I-44122 Ferrara (Italy)

    2016-06-15

    Purpose: Dual-energy image subtraction represents a useful tool to improve the detectability of small lesions, especially in dense breasts. A feature it shares with all x-ray imaging techniques is the appearance of fluctuations in the texture of the background, which can obscure the visibility of interesting details. The aim of the work is to investigate the main noise sources, in order to create a better performing subtraction mechanism. In particular, the structural noise cancellation was achieved by means of a suitable extension of the dual-energy algorithm. Methods: The effect of the cancellation procedure was tested on an analytical simulation of a target with varying structural composition. Subsequently, the subtraction algorithm was also applied to a set of actual radiographs of a breast phantom exhibiting a nonuniform background pattern. The background power spectra of the outcomes were computed and compared to the ones obtained from a standard subtraction algorithm. Results: The comparison between the standard and the proposed cancellations showed an overall suppression of the magnitudes of the spectra, as well as a flattening of the frequency dependence of the structural component of the noise. Conclusions: The proposed subtraction procedure provides an effective cancellation of the residual background fluctuations. When combined with the polychromatic correction already described in a companion publication, it results in a high performing dual-energy subtraction scheme for commercial mammography units.

  18. Identification of hand motion using background subtraction method and extraction of image binary with backpropagation neural network on skeleton model

    Science.gov (United States)

    Fauziah; Wibowo, E. P.; Madenda, S.; Hustinawati

    2018-03-01

    Capturing and recording motion in human is mostly done with the aim for sports, health, animation films, criminality, and robotic applications. In this study combined background subtraction and back propagation neural network. This purpose to produce, find similarity movement. The acquisition process using 8 MP resolution camera MP4 format, duration 48 seconds, 30frame/rate. video extracted produced 1444 pieces and results hand motion identification process. Phase of image processing performed is segmentation process, feature extraction, identification. Segmentation using bakground subtraction, extracted feature basically used to distinguish between one object to another object. Feature extraction performed by using motion based morfology analysis based on 7 invariant moment producing four different classes motion: no object, hand down, hand-to-side and hands-up. Identification process used to recognize of hand movement using seven inputs. Testing and training with a variety of parameters tested, it appears that architecture provides the highest accuracy in one hundred hidden neural network. The architecture is used propagate the input value of the system implementation process into the user interface. The result of the identification of the type of the human movement has been clone to produce the highest acuracy of 98.5447%. The training process is done to get the best results.

  19. Tomographic image via background subtraction using an x-ray projection image and a priori computed tomography

    International Nuclear Information System (INIS)

    Zhang Jin; Yi Byongyong; Lasio, Giovanni; Suntharalingam, Mohan; Yu, Cedric

    2009-01-01

    Kilovoltage x-ray projection images (kV images for brevity) are increasingly available in image guided radiotherapy (IGRT) for patient positioning. These images are two-dimensional (2D) projections of a three-dimensional (3D) object along the x-ray beam direction. Projecting a 3D object onto a plane may lead to ambiguities in the identification of anatomical structures and to poor contrast in kV images. Therefore, the use of kV images in IGRT is mainly limited to bony landmark alignments. This work proposes a novel subtraction technique that isolates a slice of interest (SOI) from a kV image with the assistance of a priori information from a previous CT scan. The method separates structural information within a preselected SOI by suppressing contributions to the unprocessed projection from out-of-SOI-plane structures. Up to a five-fold increase in the contrast-to-noise ratios (CNRs) was observed in selected regions of the isolated SOI, when compared to the original unprocessed kV image. The tomographic image via background subtraction (TIBS) technique aims to provide a quick snapshot of the slice of interest with greatly enhanced image contrast over conventional kV x-ray projections for fast and accurate image guidance of radiation therapy. With further refinements, TIBS could, in principle, provide real-time tumor localization using gantry-mounted x-ray imaging systems without the need for implanted markers.

  20. High dynamic range low-noise focal plane readout for VLWIR applications implemented with current mode background subtraction

    Science.gov (United States)

    Yang, Guang; Sun, Chao; Shaw, Timothy; Wrigley, Chris; Peddada, Pavani; Blazejewski, Edward R.; Pain, Bedabrata

    1998-09-01

    Design and operation of a low noise CMOS focal pa;ne readout circuit with ultra-high charge handling capacity is presented. Designed for high-background, VLWIR detector readout, each readout unit cell use an accurate dynamic current memory for automatic subtraction of the dark pedestal in current domain enabling measurement of small signals 85 dB below the dark level. The redout circuit operates with low-power dissipation, high linearity, and is capable of handling pedestal currents up to 300 nA. Measurements indicate an effective charge handling capacity of over 5 X 10(superscript 9) charges/pixel with less than 10(superscript 5) electrons of input referred noise.

  1. Operator-independent method for background subtraction in adrenal-uptake measurements: concise communication

    International Nuclear Information System (INIS)

    Koral, K.F.; Sarkar, S.D.

    1977-01-01

    A new computer program for adrenal-uptake measurements is presented in which the algorithm identifies the adrenal and background regions automatically after being given a starting point in the image. Adrenal uptakes and results of reproducibility tests are given for patients injected with [ 131 I] 6β-iodomethyl-19-norcholesterol. The data to date indicate no overlap in the percent-of-dose uptakes for normal patients and patients with Cushing's disease and Cushing's syndrome

  2. Probing Large-scale Coherence between Spitzer IR and Chandra X-Ray Source-subtracted Cosmic Backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Cappelluti, N.; Urry, M. [Yale Center for Astronomy and Astrophysics, P.O. Box 208120, New Haven, CT 06520 (United States); Arendt, R. [University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States); Kashlinsky, A. [Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Li, Y.; Hasinger, G. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Helgason, K. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States); Natarajan, P. [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Finoguenov, A. [Max-Planck-Institut für extraterrestrische Physik, Postfach 1312, D-85741, Garching bei München (Germany)

    2017-09-20

    We present new measurements of the large-scale clustering component of the cross-power spectra of the source-subtracted Spitzer -IRAC cosmic infrared background and Chandra -ACIS cosmic X-ray background surface brightness fluctuations Our investigation uses data from the Chandra Deep Field South, Hubble Deep Field North, Extended Groth Strip/AEGIS field, and UDS/SXDF surveys, comprising 1160 Spitzer hours and ∼12 Ms of Chandra data collected over a total area of 0.3 deg{sup 2}. We report the first (>5 σ ) detection of a cross-power signal on large angular scales >20″ between [0.5–2] keV and the 3.6 and 4.5 μ m bands, at ∼5 σ and 6.3 σ significance, respectively. The correlation with harder X-ray bands is marginally significant. Comparing the new observations with existing models for the contribution of the known unmasked source population at z < 7, we find an excess of about an order of magnitude at 5 σ confidence. We discuss possible interpretations for the origin of this excess in terms of the contribution from accreting early black holes (BHs), including both direct collapse BHs and primordial BHs, as well as from scattering in the interstellar medium and intra-halo light.

  3. Infrared Thermography Approach for Effective Shielding Area of Field Smoke Based on Background Subtraction and Transmittance Interpolation.

    Science.gov (United States)

    Tang, Runze; Zhang, Tonglai; Chen, Yongpeng; Liang, Hao; Li, Bingyang; Zhou, Zunning

    2018-05-06

    Effective shielding area is a crucial indicator for the evaluation of the infrared smoke-obscuring effectiveness on the battlefield. The conventional methods for assessing the shielding area of the smoke screen are time-consuming and labor intensive, in addition to lacking precision. Therefore, an efficient and convincing technique for testing the effective shielding area of the smoke screen has great potential benefits in the smoke screen applications in the field trial. In this study, a thermal infrared sensor with a mid-wavelength infrared (MWIR) range of 3 to 5 μm was first used to capture the target scene images through clear as well as obscuring smoke, at regular intervals. The background subtraction in motion detection was then applied to obtain the contour of the smoke cloud at each frame. The smoke transmittance at each pixel within the smoke contour was interpolated based on the data that was collected from the image. Finally, the smoke effective shielding area was calculated, based on the accumulation of the effective shielding pixel points. One advantage of this approach is that it utilizes only one thermal infrared sensor without any other additional equipment in the field trial, which significantly contributes to the efficiency and its convenience. Experiments have been carried out to demonstrate that this approach can determine the effective shielding area of the field infrared smoke both practically and efficiently.

  4. Infrared Thermography Approach for Effective Shielding Area of Field Smoke Based on Background Subtraction and Transmittance Interpolation

    Directory of Open Access Journals (Sweden)

    Runze Tang

    2018-05-01

    Full Text Available Effective shielding area is a crucial indicator for the evaluation of the infrared smoke-obscuring effectiveness on the battlefield. The conventional methods for assessing the shielding area of the smoke screen are time-consuming and labor intensive, in addition to lacking precision. Therefore, an efficient and convincing technique for testing the effective shielding area of the smoke screen has great potential benefits in the smoke screen applications in the field trial. In this study, a thermal infrared sensor with a mid-wavelength infrared (MWIR range of 3 to 5 μm was first used to capture the target scene images through clear as well as obscuring smoke, at regular intervals. The background subtraction in motion detection was then applied to obtain the contour of the smoke cloud at each frame. The smoke transmittance at each pixel within the smoke contour was interpolated based on the data that was collected from the image. Finally, the smoke effective shielding area was calculated, based on the accumulation of the effective shielding pixel points. One advantage of this approach is that it utilizes only one thermal infrared sensor without any other additional equipment in the field trial, which significantly contributes to the efficiency and its convenience. Experiments have been carried out to demonstrate that this approach can determine the effective shielding area of the field infrared smoke both practically and efficiently.

  5. Robust constraint on cosmic textures from the cosmic microwave background.

    Science.gov (United States)

    Feeney, Stephen M; Johnson, Matthew C; Mortlock, Daniel J; Peiris, Hiranya V

    2012-06-15

    Fluctuations in the cosmic microwave background (CMB) contain information which has been pivotal in establishing the current cosmological model. These data can also be used to test well-motivated additions to this model, such as cosmic textures. Textures are a type of topological defect that can be produced during a cosmological phase transition in the early Universe, and which leave characteristic hot and cold spots in the CMB. We apply bayesian methods to carry out a rigorous test of the texture hypothesis, using full-sky data from the Wilkinson Microwave Anisotropy Probe. We conclude that current data do not warrant augmenting the standard cosmological model with textures. We rule out at 95% confidence models that predict more than 6 detectable cosmic textures on the full sky.

  6. Probabilistic BPRRC: Robust Change Detection against Illumination Changes and Background Movements

    Science.gov (United States)

    Yokoi, Kentaro

    This paper presents Probabilistic Bi-polar Radial Reach Correlation (PrBPRRC), a change detection method that is robust against illumination changes and background movements. Most of the traditional change detection methods are robust against either illumination changes or background movements; BPRRC is one of the illumination-robust change detection methods. We introduce a probabilistic background texture model into BPRRC and add the robustness against background movements including foreground invasions such as moving cars, walking people, swaying trees, and falling snow. We show the superiority of PrBPRRC in the environment with illumination changes and background movements by using three public datasets and one private dataset: ATON Highway data, Karlsruhe traffic sequence data, PETS 2007 data, and Walking-in-a-room data.

  7. 201Tl in myocardial diagnosis: studies on the influence of dipyridamole, dobutamine ergometer exercise and background subtraction on the 201Tl myocadial scintiscam

    International Nuclear Information System (INIS)

    Seiderer, M.

    1979-01-01

    Changes in 201 Tl myocardial scintiscans upon administration of dipyridamole or dobutamine and upon ergometer exercise relative to scintiscans at rest were investigated as well as the influence of myocardial background subtraction on scintiscan quality and information. A total of 90 201 Tl examinations were carried out in 59 patients. 18 patients had no myocardial disease, 30 patients had a coronary disease, 5 patients suffered from cardiomyopathy and 6 from left ventricular hypertrophy. The findings are discussed in detail. (orig.) [de

  8. A robust background regression based score estimation algorithm for hyperspectral anomaly detection

    Science.gov (United States)

    Zhao, Rui; Du, Bo; Zhang, Liangpei; Zhang, Lefei

    2016-12-01

    Anomaly detection has become a hot topic in the hyperspectral image analysis and processing fields in recent years. The most important issue for hyperspectral anomaly detection is the background estimation and suppression. Unreasonable or non-robust background estimation usually leads to unsatisfactory anomaly detection results. Furthermore, the inherent nonlinearity of hyperspectral images may cover up the intrinsic data structure in the anomaly detection. In order to implement robust background estimation, as well as to explore the intrinsic data structure of the hyperspectral image, we propose a robust background regression based score estimation algorithm (RBRSE) for hyperspectral anomaly detection. The Robust Background Regression (RBR) is actually a label assignment procedure which segments the hyperspectral data into a robust background dataset and a potential anomaly dataset with an intersection boundary. In the RBR, a kernel expansion technique, which explores the nonlinear structure of the hyperspectral data in a reproducing kernel Hilbert space, is utilized to formulate the data as a density feature representation. A minimum squared loss relationship is constructed between the data density feature and the corresponding assigned labels of the hyperspectral data, to formulate the foundation of the regression. Furthermore, a manifold regularization term which explores the manifold smoothness of the hyperspectral data, and a maximization term of the robust background average density, which suppresses the bias caused by the potential anomalies, are jointly appended in the RBR procedure. After this, a paired-dataset based k-nn score estimation method is undertaken on the robust background and potential anomaly datasets, to implement the detection output. The experimental results show that RBRSE achieves superior ROC curves, AUC values, and background-anomaly separation than some of the other state-of-the-art anomaly detection methods, and is easy to implement

  9. Fluorescence background subtraction technique for hybrid fluorescence molecular tomography/x-ray computed tomography imaging of a mouse model of early stage lung cancer.

    Science.gov (United States)

    Ale, Angelique; Ermolayev, Vladimir; Deliolanis, Nikolaos C; Ntziachristos, Vasilis

    2013-05-01

    The ability to visualize early stage lung cancer is important in the study of biomarkers and targeting agents that could lead to earlier diagnosis. The recent development of hybrid free-space 360-deg fluorescence molecular tomography (FMT) and x-ray computed tomography (XCT) imaging yields a superior optical imaging modality for three-dimensional small animal fluorescence imaging over stand-alone optical systems. Imaging accuracy was improved by using XCT information in the fluorescence reconstruction method. Despite this progress, the detection sensitivity of targeted fluorescence agents remains limited by nonspecific background accumulation of the fluorochrome employed, which complicates early detection of murine cancers. Therefore we examine whether x-ray CT information and bulk fluorescence detection can be combined to increase detection sensitivity. Correspondingly, we research the performance of a data-driven fluorescence background estimator employed for subtraction of background fluorescence from acquisition data. Using mice containing known fluorochromes ex vivo, we demonstrate the reduction of background signals from reconstructed images and sensitivity improvements. Finally, by applying the method to in vivo data from K-ras transgenic mice developing lung cancer, we find small tumors at an early stage compared with reconstructions performed using raw data. We conclude with the benefits of employing fluorescence subtraction in hybrid FMT-XCT for early detection studies.

  10. Subtractive Leadership

    Science.gov (United States)

    Larwin, K. H.; Thomas, Eugene M.; Larwin, David A.

    2015-01-01

    This paper introduces a new term and concept to the leadership discourse: Subtractive Leadership. As an extension of the distributive leadership model, the notion of subtractive leadership refers to a leadership style that detracts from organizational culture and productivity. Subtractive leadership fails to embrace and balance the characteristics…

  11. Effect of sumatriptan on cerebral blood flow during migraine headache. Measurement by sequential SPECT used 99mTc-ECD background subtraction method

    International Nuclear Information System (INIS)

    Ueda, Takashi; Torihara, Yoshito; Tsuneyoshi, Noritaka; Ikeda, Yoshitomo

    2001-01-01

    The present study was designed to examine the effect of sumatriptan on regional cerebral blood flow (CBF) during migraine headache. Nine cases were examined by 99m Tc-ECD background subtraction method for the absolute value measurement of regional CBF before and after sumatriptan injection. rCBF except for occipital and perioccipital lobes, were increased 10-20% during migraine headache and significant decreases were observed by sumatriptan injection. Two cases of nine had transiently increased systemic blood pressure and cardiac pulse rate, however, all cases improved migraine headache after injection of sumatriptan. (author)

  12. Effect of sumatriptan on cerebral blood flow during migraine headache. Measurement by sequential SPECT used {sup 99m}Tc-ECD background subtraction method

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, Takashi; Torihara, Yoshito; Tsuneyoshi, Noritaka; Ikeda, Yoshitomo [Miyazaki Social Insurance Hospital (Japan)

    2001-07-01

    The present study was designed to examine the effect of sumatriptan on regional cerebral blood flow (CBF) during migraine headache. Nine cases were examined by {sup 99m}Tc-ECD background subtraction method for the absolute value measurement of regional CBF before and after sumatriptan injection. rCBF except for occipital and perioccipital lobes, were increased 10-20% during migraine headache and significant decreases were observed by sumatriptan injection. Two cases of nine had transiently increased systemic blood pressure and cardiac pulse rate, however, all cases improved migraine headache after injection of sumatriptan. (author)

  13. Space and time resolved measurements of ion temperature with the CVI 5292 A charge exchange recombination line after subtracting background radiation

    International Nuclear Information System (INIS)

    Ida, K.; Hidekuma, S.

    1988-08-01

    An ion temperature profile has been obtained with the CVI 5292 A (n = 8 - 7) charge exchange recombination (CXR) line using a space and wave-length resolving visible spectrometer installed on the JIPP TII-U tokamak. Two sets of 50 channels optical fiber arrays: one viewing a fast neutral hydrogen beam (CXR channels) and the other viewing off the neutral beam line (background channels), is arranged on the entrance slit of the spectrometer. This spectrometer is coupled to an image intensifier and CCD detector at the focal plane and provides temperature profile every 1/60 second. An ion temperature is derived from the Doppler broadened line profile after subtracting the simultaneously measured cold component (background channels), which is due to electron-excitation and/or charge exchange recombination in the plasma periphery. Alternative approach to obtain the ion temperature profile without CXR is also demonstrated. This method is based on an Abel inversion technique for each wavelength separately. (author)

  14. EPR dosimetry of whole deciduous tooth using a constant rotation goniometer and background subtraction with a dentine standard

    International Nuclear Information System (INIS)

    Haskell, E.H.; Hayes, R.B.; Kenner, G.H.

    1996-01-01

    We report here a rapid method of electron paramagnetic resonance (EPR) dosimetry of dental enamel which will allow screening of whole deciduous teeth of children following a nuclear accident. The technique requires virtually no sample preparation and is capable of measuring doses of less than 100 mGy. Teeth may be scanned for threshold dose levels without the need for added calibration doses and those of particular interest may be more accurately examined using the additive dose method. The success of the technique lies in the elimination of anisotropic effects by rotation of spectra from the empty cavity and a standard background tooth. Normalization using in- cavity Mn++ standards is also employed

  15. COMPARISON OF BACKGROUND SUBTRACTION, SOBEL, ADAPTIVE MOTION DETECTION, FRAME DIFFERENCES, AND ACCUMULATIVE DIFFERENCES IMAGES ON MOTION DETECTION

    Directory of Open Access Journals (Sweden)

    Dara Incam Ramadhan

    2018-02-01

    Full Text Available Nowadays, digital image processing is not only used to recognize motionless objects, but also used to recognize motions objects on video. One use of moving object recognition on video is to detect motion, which implementation can be used on security cameras. Various methods used to detect motion have been developed so that in this research compared some motion detection methods, namely Background Substraction, Adaptive Motion Detection, Sobel, Frame Differences and Accumulative Differences Images (ADI. Each method has a different level of accuracy. In the background substraction method, the result obtained 86.1% accuracy in the room and 88.3% outdoors. In the sobel method the result of motion detection depends on the lighting conditions of the room being supervised. When the room is in bright condition, the accuracy of the system decreases and when the room is dark, the accuracy of the system increases with an accuracy of 80%. In the adaptive motion detection method, motion can be detected with a condition in camera visibility there is no object that is easy to move. In the frame difference method, testing on RBG image using average computation with threshold of 35 gives the best value. In the ADI method, the result of accuracy in motion detection reached 95.12%.

  16. ON THE ADVISABILITY OF REJECTION OF SUBTRACTION OF BACKGROUND DOSIMETERS INDICATION VALUES FROM THE MEASURED VALUES OF INDIVIDUAL DOSES OF OCCUPATIONAL EXPOSURE OF A-GROUP PERSONNEL

    Directory of Open Access Journals (Sweden)

    A. N. Barkovskiy

    2013-01-01

    Full Text Available An article contains substantiation of advisability of rejection of subtraction of background dosimeters indication values from the measured values of individual doses of occupational exposure of A-group personnel in the process of carrying out of individual dosimetry control of medical organizations stuff which was implemented in the Methodical Guideline 2.6.1.3015-12. It is shown that mentioned procedure is firstly incorrect when we deal with low doses, when the impact of natural exposure could be really considerable and secondary senseless when we deal with dose values close to the dose limit value for A-group personnel when the impact of natural exposure is much lower then the error of measurements. It is suggested to carry out the account of the impact of natural exposure into personnel average doses basing on the analysis of statistical distributions of personnel individual doses and on indications of background dosimeters. It is suggested to add the information about indications of background dosimeters into the Base of Federal Statistical Supervision № 1-DOS as it is prescribed in the Methodical Guideline 2.6.1.3015-12. This article is the respond to the article of A.I. Grigoriev published in the present issue of Journal, in which the author contests the reasonableness of this provision.

  17. On-orbit real-time robust cooperative target identification in complex background

    Directory of Open Access Journals (Sweden)

    Wen Zhuoman

    2015-10-01

    Full Text Available Cooperative target identification is the prerequisite for the relative position and orientation measurement between the space robot arm and the to-be-arrested object. We propose an on-orbit real-time robust algorithm for cooperative target identification in complex background using the features of circle and lines. It first extracts only the interested edges in the target image using an adaptive threshold and refines them to about single-pixel-width with improved non-maximum suppression. Adapting a novel tracking approach, edge segments changing smoothly in tangential directions are obtained. With a small amount of calculation, large numbers of invalid edges are removed. From the few remained edges, valid circular arcs are extracted and reassembled to obtain circles according to a reliable criterion. Finally, the target is identified if there are certain numbers of straight lines whose relative positions with the circle match the known target pattern. Experiments demonstrate that the proposed algorithm accurately identifies the cooperative target within the range of 0.3–1.5 m under complex background at the speed of 8 frames per second, regardless of lighting condition and target attitude. The proposed algorithm is very suitable for real-time visual measurement of space robot arm because of its robustness and small memory requirement.

  18. A retention-time-shift-tolerant background subtraction and noise reduction algorithm (BgS-NoRA) for extraction of drug metabolites in liquid chromatography/mass spectrometry data from biological matrices.

    Science.gov (United States)

    Zhu, Peijuan; Ding, Wei; Tong, Wei; Ghosal, Anima; Alton, Kevin; Chowdhury, Swapan

    2009-06-01

    A retention-time-shift-tolerant background subtraction and noise reduction algorithm (BgS-NoRA) is implemented using the statistical programming language R to remove non-drug-related ion signals from accurate mass liquid chromatography/mass spectrometry (LC/MS) data. The background-subtraction part of the algorithm is similar to a previously published procedure (Zhang H and Yang Y. J. Mass Spectrom. 2008, 43: 1181-1190). The noise reduction algorithm (NoRA) is an add-on feature to help further clean up the residual matrix ion noises after background subtraction. It functions by removing ion signals that are not consistent across many adjacent scans. The effectiveness of BgS-NoRA was examined in biological matrices by spiking blank plasma extract, bile and urine with diclofenac and ibuprofen that have been pre-metabolized by microsomal incubation. Efficient removal of background ions permitted the detection of drug-related ions in in vivo samples (plasma, bile, urine and feces) obtained from rats orally dosed with (14)C-loratadine with minimal interference. Results from these experiments demonstrate that BgS-NoRA is more effective in removing analyte-unrelated ions than background subtraction alone. NoRA is shown to be particularly effective in the early retention region for urine samples and middle retention region for bile samples, where the matrix ion signals still dominate the total ion chromatograms (TICs) after background subtraction. In most cases, the TICs after BgS-NoRA are in excellent qualitative correlation to the radiochromatograms. BgS-NoRA will be a very useful tool in metabolite detection and identification work, especially in first-in-human (FIH) studies and multiple dose toxicology studies where non-radio-labeled drugs are administered. Data from these types of studies are critical to meet the latest FDA guidance on Metabolite in Safety Testing (MIST). Copyright (c) 2009 John Wiley & Sons, Ltd.

  19. A background subtraction routine for enhancing energy-filtered plasmon images of MgAl2O4 implanted with Al+ and Mg+ ions

    International Nuclear Information System (INIS)

    Evans, N.D.; Kenik, E.A.; Bentley, J.; Zinkle, S.J.

    1995-01-01

    MgAl 2 O 4 , a candidate fusion reactor material, was irradiated with Al + or Mg + ions; electron energy-loss spectra and energy-filtered plasmon images showed that metallic Al colloids are present in the ion-irradiated regions. This paper shows the subtraction of the spinel plasmon component in images using 15-eV-loss electrons in some detail

  20. Robust

    DEFF Research Database (Denmark)

    2017-01-01

    Robust – Reflections on Resilient Architecture’, is a scientific publication following the conference of the same name in November of 2017. Researches and PhD-Fellows, associated with the Masters programme: Cultural Heritage, Transformation and Restoration (Transformation), at The Royal Danish...

  1. A novel approach to background subtraction in contrast-enhanced dual-energy digital mammography with commercially available mammography devices: Polychromaticity correction

    Energy Technology Data Exchange (ETDEWEB)

    Contillo, Adriano, E-mail: contillo@fe.infn.it; Di Domenico, Giovanni; Cardarelli, Paolo; Gambaccini, Mauro; Taibi, Angelo [Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Via Saragat 1, Ferrara I-44122 (Italy)

    2015-11-15

    Purpose: Contrast-enhanced digital mammography is an image subtraction technique that is able to improve the detectability of lesions in dense breasts. One of the main sources of error, when the technique is performed by means of commercial mammography devices, is represented by the intrinsic polychromaticity of the x-ray beams. The aim of the work is to propose an iterative procedure, which only assumes the knowledge of a small set of universal quantities, to take into account the polychromaticity and correct the subtraction results accordingly. Methods: In order to verify the procedure, it has been applied to an analytical simulation of a target containing a contrast medium and to actual radiographs of a breast phantom containing cavities filled with a solution of the same medium. Results: The reconstructed densities of contrast medium were compared, showing very good agreement between the theoretical predictions and the experimental results already after the first iteration. Furthermore, the convergence of the iterative procedure was studied, showing that only a small number of iterations is necessary to reach limiting values. Conclusions: The proposed procedure represents an efficient solution to the polychromaticity issue, qualifying therefore as a viable alternative to inverse-map functions.

  2. A Robust Algorithm to Determine the Topology of Space from the Cosmic Microwave Background Radiation

    OpenAIRE

    Weeks, Jeffrey R.

    2001-01-01

    Satellite measurements of the cosmic microwave back-ground radiation will soon provide an opportunity to test whether the universe is multiply connected. This paper presents a new algorithm for deducing the topology of the universe from the microwave background data. Unlike an older algorithm, the new algorithm gives the curvature of space and the radius of the last scattering surface as outputs, rather than requiring them as inputs. The new algorithm is also more tolerant of erro...

  3. A novel robust and efficient algorithm for charge particle tracking in high background flux

    International Nuclear Information System (INIS)

    Fanelli, C; Cisbani, E; Dotto, A Del

    2015-01-01

    The high luminosity that will be reached in the new generation of High Energy Particle and Nuclear physics experiments implies large high background rate and large tracker occupancy, representing therefore a new challenge for particle tracking algorithms. For instance, at Jefferson Laboratory (JLab) (VA,USA), one of the most demanding experiment in this respect, performed with a 12 GeV electron beam, is characterized by a luminosity up to 10 39 cm -2 s -1 . To this scope, Gaseous Electron Multiplier (GEM) based trackers are under development for a new spectrometer that will operate at these high rates in the Hall A of JLab. Within this context, we developed a new tracking algorithm, based on a multistep approach: (i) all hardware - time and charge - information are exploited to minimize the number of hits to associate; (ii) a dedicated Neural Network (NN) has been designed for a fast and efficient association of the hits measured by the GEM detector; (iii) the measurements of the associated hits are further improved in resolution through the application of Kalman filter and Rauch- Tung-Striebel smoother. The algorithm is shortly presented along with a discussion of the promising first results. (paper)

  4. Robust Likelihoods for Inflationary Gravitational Waves from Maps of Cosmic Microwave Background Polarization

    Science.gov (United States)

    Switzer, Eric Ryan; Watts, Duncan J.

    2016-01-01

    The B-mode polarization of the cosmic microwave background provides a unique window into tensor perturbations from inflationary gravitational waves. Survey effects complicate the estimation and description of the power spectrum on the largest angular scales. The pixel-space likelihood yields parameter distributions without the power spectrum as an intermediate step, but it does not have the large suite of tests available to power spectral methods. Searches for primordial B-modes must rigorously reject and rule out contamination. Many forms of contamination vary or are uncorrelated across epochs, frequencies, surveys, or other data treatment subsets. The cross power and the power spectrum of the difference of subset maps provide approaches to reject and isolate excess variance. We develop an analogous joint pixel-space likelihood. Contamination not modeled in the likelihood produces parameter-dependent bias and complicates the interpretation of the difference map. We describe a null test that consistently weights the difference map. Excess variance should either be explicitly modeled in the covariance or be removed through reprocessing the data.

  5. Despina Hatzifotiadou: ALICE Master Class 4 - Demonstration of the software for the 2nd part of the exercise - invariant mass spectra - background subtraction and calculation of number of Kaons, Lambdas, antiLambdas.

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    This is the 4th of 4 short online videos. It contains a demonstration of the software for the 2nd part of the exercise, related to invariant mass spectra - background subtraction and calculation of number of Kaons, Lambdas, antiLambdas. More details and related links on this indico event page. In more detail: What is Physics Master Classes Students after morning lectures, run programmes in the afternoon to do measurements. These tutorials are about how to use the software required to do these measurements. Background info and examples  Looking for strange particles with ALICE http://aliceinfo.cern.ch/Public/MasterCL/MasterClassWebpage.html Introduction to first part of the exercise : what are strange particles, V0 decays, invariant mass. Demonstration of the software for the 1st part of the exercise - visual identification of V0s Introduction to second part of the exercise : strangeness enhancement; centrality of lead-lead collisions; explanation of efficiency, yield, background etc Demonstr...

  6. Chemicalome and metabolome profiling of polymethoxylated flavonoids in Citri Reticulatae Pericarpium based on an integrated strategy combining background subtraction and modified mass defect filter in a Microsoft Excel Platform.

    Science.gov (United States)

    Zeng, Su-Ling; Duan, Li; Chen, Bai-Zhong; Li, Ping; Liu, E-Hu

    2017-07-28

    Detection of metabolites in complex biological matrixes is a great challenge because of the background noise and endogenous components. Herein, we proposed an integrated strategy that combined background subtraction program and modified mass defect filter (MMDF) data mining in a Microsoft Excel platform for chemicalome and metabolome profiling of the polymethoxylated flavonoids (PMFs) in Citri Reticulatae Pericarpium (CRP). The exogenously-sourced ions were firstly filtered out by the developed Visual Basic for Applications (VBA) program incorporated in the Microsoft Office. The novel MMDF strategy was proposed for detecting both target and untarget constituents and metabolites based on narrow, well-defined mass defect ranges. The approach was validated to be powerful, and potentially useful for the metabolite identification of both single compound and homologous compound mixture. We successfully identified 30 and 31 metabolites from rat biosamples after oral administration of nobiletin and tangeretin, respectively. A total of 56 PMFs compounds were chemically characterized and 125 metabolites were captured. This work demonstrated the feasibility of the integrated approach for reliable characterization of the constituents and metabolites in herbal medicines. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Statistically tuned Gaussian background subtraction technique for ...

    Indian Academy of Sciences (India)

    temporal median method and mixture of Gaussian model and performance evaluation ... to process the videos captured by unmanned aerial vehicle (UAV). ..... The output is obtained by simulation using MATLAB 2010 in a standalone PC with ...

  8. Analysis of the principal factors that intervene in the quantification of planar images of uniform distributions of 99mTc by the conjugate view method with background correction by simple subtraction

    International Nuclear Information System (INIS)

    Mora Araya, Luis Diego

    2013-01-01

    The activity of uniform distributions of 99m Tc was quantified by the conjugate view method. The necessary factors of calibration and transmission were calculated to realize the quantification. The dependence of the estimated number of accounts within the source region and variability of the value of the transmission factor were determined, according to the size established for the region of interest, keeping constant its geometry. The images of all acquisitions were corrected by environmental background radiation and radiation dispersed, by the dual energy window method (DEW). The impact of corrections in the image were checked, both qualitatively and quantitative. The acquisition to obtain the calibration factor was realized with the same configuration and the same conditions that were used to realize the acquisition for quantification; in which, the same volume and the same geometry were used to contain the distribution of the activity of 99m Tc. The volume and geometry of the same medium attenuator have obtained a calibration factor exactly in the same circumstances in which have quantified. The behavior of the estimation of the calibration factor of the gamma camera was analyzed, according to the decay corrections of the activity and the attenuation that are applied. The dependence of the calibration factors and transmission were analyzed, according to the region of interest used in the corresponding images to estimate their values. The behavior of the estimation of the activity was determined, according to all possible combinations of the factors studied that have intervened in the quantification algorithm of conjugate view, namely, the size of the region of interest corresponding to the source region, the transmission factor , the calibration factor and background correction by simple subtraction. The results obtained of the estimates of the activity were compared. A tendency is established, indicating which have been combinations of the studied factors that

  9. Automatic dipole subtraction

    International Nuclear Information System (INIS)

    Hasegawa, K.

    2008-01-01

    The Catani-Seymour dipole subtraction is a general procedure to treat infrared divergences in real emission processes at next-to-leading order in QCD. We automatized the procedure in a computer code. The code is useful especially for the processes with many parton legs. In this talk, we first explain the algorithm of the dipole subtraction and the whole structure of our code. After that we show the results for some processes where the infrared divergences of real emission processes are subtracted. (author)

  10. Subtracting and Fitting Histograms using Profile Likelihood

    CERN Document Server

    D'Almeida, F M L

    2008-01-01

    It is known that many interesting signals expected at LHC are of unknown shape and strongly contaminated by background events. These signals will be dif cult to detect during the rst years of LHC operation due to the initial low luminosity. In this work, one presents a method of subtracting histograms based on the pro le likelihood function when the background is previously estimated by Monte Carlo events and one has low statistics. Estimators for the signal in each bin of the histogram difference are calculated so as limits for the signals with 68.3% of Con dence Level in a low statistics case when one has a exponential background and a Gaussian signal. The method can also be used to t histograms when the signal shape is known. Our results show a good performance and avoid the problem of negative values when subtracting histograms.

  11. Automating dipole subtraction

    International Nuclear Information System (INIS)

    Hasegawa, K.; Moch, S.; Uwer, P.

    2008-07-01

    We report on automating the Catani-Seymour dipole subtraction which is a general procedure to treat infrared divergences in real emission processes at next-to-leading order in QCD. The automatization rests on three essential steps: the creation of the dipole terms, the calculation of the color linked squared Born matrix elements, and the evaluation of different helicity amplitudes. The routines have been tested for a number of complex processes, such as the real emission process gg→t anti tggg. (orig.)

  12. Automating dipole subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, K.; Moch, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Uwer, P. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Theoretische Teilchenphysik

    2008-07-15

    We report on automating the Catani-Seymour dipole subtraction which is a general procedure to treat infrared divergences in real emission processes at next-to-leading order in QCD. The automatization rests on three essential steps: the creation of the dipole terms, the calculation of the color linked squared Born matrix elements, and the evaluation of different helicity amplitudes. The routines have been tested for a number of complex processes, such as the real emission process gg{yields}t anti tggg. (orig.)

  13. Intraarterial digital subtraction angiography

    International Nuclear Information System (INIS)

    Davis, P.C.

    1987-01-01

    Digital subtraction angiography (DSA) refers to a radiographic technique of amplifying low levels of contrast from intravascular iodine into an acceptable image of vascular anatomy. Initial enthusiasm suggested that DSA using intravenous injections (IV-DSA) would eliminate most conventional film-screen angiographic studies. It was soon apparent, however, that IV-DSA examinations were often compromised in those patients who most needed a less invasive study. Indeed, only a 70 to 85 percent accuracy rate was achieved with IV-DSA, primarily due to motion artifact, poor cardiac output, overlap of pertinent vessels, and inability to resolve smaller vessels

  14. Colourful FKS subtraction

    CERN Document Server

    Frixione, Stefano

    2011-01-01

    I formulate in a colour-friendly way the FKS method for the computation of QCD cross sections at the next-to-leading order accuracy. This is achieved through the definition of subtraction terms for squared matrix elements, constructed with single colour-dressed or pairs of colour-ordered amplitudes. The latter approach relies on the use of colour flows, is exact to all orders in $N$, and is thus particularly suited to being organized as a systematic expansion in 1/N.

  15. Digital subtraction angiography (DSA)

    International Nuclear Information System (INIS)

    Ludwig, J.W.; Eikelboom, B.C.; Van Schaik, C.C.; Taams, A.J.; Teeuwen, C.

    1985-01-01

    Besides the non-invasive techniques, angiography remains essential. The disadvantages of angiography are the complexity of the procedure and the possibility of complications. Digital subtraction angiography (DSA) is a considerable improvement in the examination of vessels. In DSA, subtraction combined with enhancement of the signals allows the use of intravenous injection to obtain good images of the arteries. However, when the contrast material is supplied intravenously, a rather large amount of contrast material is necessary to obtain images of good quality. Quantities of 30-40 cc of contrast material are required. The advantage of the intravenous injection of contrast material rather than the use of a catheter to deliver the contrast material in loco is that it is almost non-invasive thus circumventing the complications caused by catheter manipulation in the arterial system. This makes it possible to apply this method on an out-patient basis. DSA can also be applied with intra-arterial selective injection of the contrast material. In this case, the strong enhancement with DSA allows the use of a small quantity of contrast material while still obtaining images of the vessels with good contrast definition

  16. LTD windows of the STDP learning rule and synaptic connections having a large transmission delay enable robust sequence learning amid background noise.

    Science.gov (United States)

    Hayashi, Hatsuo; Igarashi, Jun

    2009-06-01

    Spike-timing-dependent synaptic plasticity (STDP) is a simple and effective learning rule for sequence learning. However, synapses being subject to STDP rules are readily influenced in noisy circumstances because synaptic conductances are modified by pre- and postsynaptic spikes elicited within a few tens of milliseconds, regardless of whether those spikes convey information or not. Noisy firing existing everywhere in the brain may induce irrelevant enhancement of synaptic connections through STDP rules and would result in uncertain memory encoding and obscure memory patterns. We will here show that the LTD windows of the STDP rules enable robust sequence learning amid background noise in cooperation with a large signal transmission delay between neurons and a theta rhythm, using a network model of the entorhinal cortex layer II with entorhinal-hippocampal loop connections. The important element of the present model for robust sequence learning amid background noise is the symmetric STDP rule having LTD windows on both sides of the LTP window, in addition to the loop connections having a large signal transmission delay and the theta rhythm pacing activities of stellate cells. Above all, the LTD window in the range of positive spike-timing is important to prevent influences of noise with the progress of sequence learning.

  17. A comparison of subtracted images from dental subtraction programs

    International Nuclear Information System (INIS)

    Han, Won Jeong

    2002-01-01

    To compare the standard deviation of gray levels on digital subtracted images obtained by different dental subtraction programs. Paired periapical films were taken at the lower premolar and molar areas of the phantoms involving human mandible. The bite registration group used Rinn XCP equipment and bite registration material, based on polyvinyl siloxane, for standardization. The no bite registration group used only Rinn XCP equipment. The periapical film images were digitized at 1200 dpi resolution and 256 gray levels by a flat bed scanner with transparency unit. Dental digital subtraction programs used for this study were Subtractor (Biomedisys Co., Korea) and Emago (Oral Diagnostic Systems, The Netherlands). To measure the similarities between the subtracted images, the standard deviations of the gray levels were obtained using a histogram of subtracted images, which were then analyzed statistically. Subtracted images obtained by using the Emago program without manual selection of corresponding points showed the lowest standard deviation of gray levels (p<0.01). And the standard deviation of gray levels was lower in subtracted images in the group of a bite registration than in the group of no use of bite registration (p<0.01). Digital radiographic subtraction without manual selection of reference points was found to be a convenient and superior method.

  18. Digital subtraction angiography

    International Nuclear Information System (INIS)

    Gmelin, E.; Arlart, I.P.

    1987-01-01

    The introduction explains the technical and physical fundamentals of digital radiography, the principles of digital subtraction, and the various filtering methods. The authors then define the requirements to be met by a DSA equipment in terms of technical components and operational performance. A very extensive chapter deals with the indications supporting intravenous or intraarterial DSA and compares the two methods, showing advantages and drawbacks with respect to practical results. Another chapter discusses the applications of DSA for cardiological diagnostics, as e.g. imaging of the coronary arteries or arterial bypasses, and explains the densitometric and planimetric evaluation of the coronary functional processes. The book also discusses less customary applications of DSA such as the sialography or dacryocystography, as well as angiologic examinations in children. The limits of the DSA methods are discussed in the last chapter, together with aspects such as the radiation exposure of the patient, and cost-benefit analyses, and potential future improvements. With 204 figs., 44 tabs [de

  19. Digital subtraction angiography

    International Nuclear Information System (INIS)

    Neuwirth, J. Jr.; Bohutova, J.

    1987-01-01

    The quality of radiodiagnostic methods to a great extent depends on the quality of the resulting image. The basic technical principles are summed up of the different parts of digital subtraction angiography apparatus and of methods of improving the image. The instrument is based on a videochain consisting of an X-ray tube, an intensifier of the radiographic image, optical parts, a video camera, an analog-to-digital converter and a computer. The main advantage of the digitally processed image is the possibility of optimizing the image into a form which will contain the biggest amount of diagnostically valuable information. Described are the mathematical operations for improving the digital image: spatial filtration, pixel shift, time filtration, image integration, time interval differentation and matched filtering. (M.D.). 8 refs., 3 figs

  20. Physical principles of cardiac digital subtraction angiography

    International Nuclear Information System (INIS)

    Buonocore, E.; Pavlicek, W.

    1986-01-01

    Advances in the applications of computers with standard radiologic equipment have resulted in the development of electronic, or so-called ''film-less'' imaging. This technique, discussed by the authors, has become of particular value in the visualization of the central vascular system and has become known as digital subtraction angiography (DSA). Commercial products have become increasingly available and are capable of converting T.V. signals, obtained by conventional fluorography, to a computed array of digital values. Addition, subtraction, and averaging of this data, result in images with adequate signal-to-noise ratios that achieve detection of low concentrations of contrast media not possible with conventional screen film techniques. Computer subtraction of unnecessary background information improves the conspicuity of the opacified vessels to permit detection of vascular structures containing a concentration of no more than 1-3 percent of contrast media. This improved visualization is possible even with intravenous peripheral injections or reduced amounts of contrast media given intraarterially. With either method of contrast media administration, DSDA has become an excellent means of anatomic demonstration of the heart and great vessels with decreased morbidity and at lower cost

  1. Self-masking subtraction tomosynthesis

    International Nuclear Information System (INIS)

    Chakraborty, D.P.; Yester, M.V.; Barnes, G.T.; Lakshminarayanan, A.V.

    1984-01-01

    The authors tested the image quality and dose savings of self-masking subtraction tomosynthesis (SST), which combines digital tomosynthesis with subtraction of a blurred self-mask. High-quality images of the inner ear of a head phantom were obtained at moderate dose savings. Although they were taken with linear motion, they did not exhibit the streaking due to off-fulcrum objects that is characteristic of conventional linear tomography. SST could reduce patient dose by a factor of at least 12 in examinations of the inner ear, and the mechanical aspects can be implemented with moderate modifications of existing instrumentation

  2. Photon Subtraction by Many-Body Decoherence

    DEFF Research Database (Denmark)

    Murray, C. R.; Mirgorodskiy, I.; Tresp, C.

    2018-01-01

    We experimentally and theoretically investigate the scattering of a photonic quantum field from another stored in a strongly interacting atomic Rydberg ensemble. Considering the many-body limit of this problem, we derive an exact solution to the scattering-induced spatial decoherence of multiple...... stored photons, allowing for a rigorous understanding of the underlying dissipative quantum dynamics. Combined with our experiments, this analysis reveals a correlated coherence-protection process in which the scattering from one excitation can shield all others from spatial decoherence. We discuss how...... this effect can be used to manipulate light at the quantum level, providing a robust mechanism for single-photon subtraction, and experimentally demonstrate this capability....

  3. Color Addition and Subtraction Apps

    Science.gov (United States)

    Ruiz, Frances; Ruiz, Michael J.

    2015-01-01

    Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step…

  4. Digital subtraction angiography in traumatology

    International Nuclear Information System (INIS)

    Steudel, A.; Harder, T.; Lackner, K.; Schneider, B.; Orellano, L.; Bonn Univ.; Bonn Univ.

    1986-01-01

    The methods, indications and results of digital subtraction angiography in traumatology are presented, based on 56 examinations. The different use of intravenous or intraarterial DSA will be discussed with respect to expanding and localisation of traumatic vascular injury. DSA is recommended as the method of choice for follow-up after vascular reconstructive procedure. (orig.) [de

  5. Digital subtraction angiography (DSA) of the heart and coronary arteries

    International Nuclear Information System (INIS)

    Struyven, J.J.; Delcour, C.; Brion, J.P.; Vandenbosch, G.; Claessens, J.

    1986-01-01

    Digital subtraction angiography has potential advantages over conventional radiography. The removal of background structures makes possible to visualize chambers of the heart, great vessels and coronary arteries with a lower iodine signal than with conventional cineangiography. Digital data used for imaging can been manipulated for assessment and quantitation of the ventricular fonction and the coronary circulation

  6. Children's Understanding of the Addition/Subtraction Complement Principle

    Science.gov (United States)

    Torbeyns, Joke; Peters, Greet; De Smedt, Bert; Ghesquière, Pol; Verschaffel, Lieven

    2016-01-01

    Background: In the last decades, children's understanding of mathematical principles has become an important research topic. Different from the commutativity and inversion principles, only few studies have focused on children's understanding of the addition/subtraction complement principle (if a - b = c, then c + b = a), mainly relying on verbal…

  7. Subtracted versus non-subtracted digital imaging in peripheral angiography

    International Nuclear Information System (INIS)

    Fink, U.; Heywang, S.; Mayr, B.; Berger, H.

    1989-01-01

    Digital subtraction angiography (DSA) plays an important role in the management of vascular diseases of the lower extremities. A disadvantage is the lack of an automatically moving table top. We used a 1,024x1,024 matrix with a large-screen intensifier system and an automated 'stepping' facility. In 161 examinations of the arteries of the lower extremity digital peripheral arteriography was performed with and without the subtraction technique. We compared the influence of different iodine concentrations in DA and DSA. Peripheral DA proved to be equal to peripheral DSA in the region of the pelvis, thigh and knee, with no adequate contrasting being obtained merely in the region of the lower leg arteries in about 45%. It is necessary to use contrast medium at a concentration of 300 mg I/ml. The installation of an automated 'stepping' facility reduces the amount of contrast' medium needed and the exposure time. (orig.)

  8. A study of transverse image reconstruction with digital subtraction angiography

    International Nuclear Information System (INIS)

    Sakamoto, Kiyoshi; Kotoura, Noriko; Terasawa, Yuuji; Oda, Masahiko; Gotou, Hiroshi; Nasada, Toshiya; Tanooka, Masao

    1995-01-01

    For digital subtraction angiography (DSA) with C-type equipment, it is possible to radiate an X-ray during rotation and to collect data at different angular settings. We tried to reconstruct transverse image from data obtained by scanning DSA images at different angular settings. 88 projection data were obtained by rotating the object at 180deg during radiation. Reconstruction was made using the convolution method with pixel value distribution for each projection. Similarly, the image quality of the reconstructed images were compared with the unsubtracted and subtracted ones. In case a part object was outside the calculating region, artifacts were generally produced. However, the artifacts were reduced by subtracting the background from the image. In addition, the cupping phenomenon caused by beam hardening was relaxed and high-quality imaging could be achieved. This method will become even more effective, if we will use it with selective angiography in which the limited area is enhanced. (author)

  9. Plasma tomographic reconstruction from tangentially viewing camera with background subtraction

    Czech Academy of Sciences Publication Activity Database

    Odstrčil, M.; Mlynář, Jan; Weinzettl, Vladimír; Háček, Pavel; Odstrčil, T.; Verdoolaege, G.; Berta, M.; Szabolics, T.; Bencze, A.

    2014-01-01

    Roč. 85, č. 1 (2014), 013509-013509 ISSN 0034-6748 R&D Projects: GA ČR GAP205/10/2055 Institutional support: RVO:61389021 Keywords : X-ray tomography * edge turbulence * tokamak * NSTX * TCV * COMPASS Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.614, year: 2014 http://scitation.aip.org/content/aip/journal/rsi/85/1/10.1063/1.4862652

  10. MUSIC-CONTENT-ADAPTIVE ROBUST PRINCIPAL COMPONENT ANALYSIS FOR A SEMANTICALLY CONSISTENT SEPARATION OF FOREGROUND AND BACKGROUND IN MUSIC AUDIO SIGNALS

    OpenAIRE

    Papadopoulos , Hélène; Ellis , Daniel P.W.

    2014-01-01

    International audience; Robust Principal Component Analysis (RPCA) is a technique to decompose signals into sparse and low rank components, and has recently drawn the attention of the MIR field for the problem of separating leading vocals from accompaniment, with appealing re-sults obtained on small excerpts of music. However, the perfor-mance of the method drops when processing entire music tracks. We present an adaptive formulation of RPCA that incorporates music content information to guid...

  11. Multivariate spatial condition mapping using subtractive fuzzy cluster means.

    Science.gov (United States)

    Sabit, Hakilo; Al-Anbuky, Adnan

    2014-10-13

    Wireless sensor networks are usually deployed for monitoring given physical phenomena taking place in a specific space and over a specific duration of time. The spatio-temporal distribution of these phenomena often correlates to certain physical events. To appropriately characterise these events-phenomena relationships over a given space for a given time frame, we require continuous monitoring of the conditions. WSNs are perfectly suited for these tasks, due to their inherent robustness. This paper presents a subtractive fuzzy cluster means algorithm and its application in data stream mining for wireless sensor systems over a cloud-computing-like architecture, which we call sensor cloud data stream mining. Benchmarking on standard mining algorithms, the k-means and the FCM algorithms, we have demonstrated that the subtractive fuzzy cluster means model can perform high quality distributed data stream mining tasks comparable to centralised data stream mining.

  12. Exercise intravenous digital subtraction angiography

    International Nuclear Information System (INIS)

    Yiannikas, J.

    1986-01-01

    Attempts to use exercise ventriculography have been made, not only to give diagnostic and perhaps even prognostic information in patients with coronary artery disease, but also in patients with valvular heart disease both before and after surgical intervention. Clearly an accurate method of assessing ventricular function under conditions of stress in various cardiac diseases would provide important information that would help in patient management. Exercise ventriculography using gated blood pool equilibrium technetium studies are widely used, but are limited by spatial resolution and by the foreshortening affects of visualizing the left ventricular chamber in the left anterior oblique view. First pass radionuclide studies have the added advantage of being able to visualize the ventricular chamber in the anterior or even the right anterior oblique view, but are even more limited by their spatial resolution problems. Several investigations have shown that digital subtraction angiography produces left ventricular images with a spatial resolution almost identical to that of conventional contrast ventriculography, but without the inherent problems of cardiac arrhythmias, which often limit the assessment of left ventricular function. Because of its ability to accurately delineate wall motion abnormalities, the technique may provide an adequate assessment of global and regional left ventricular function after exercise. Digital subtraction angiography may identify ischemic wall motion abnormalities produced by exercise in patients who already had significant permanent left ventricular damage from myocardial infarction

  13. 99mTc-RBC subtraction scintigraphy

    International Nuclear Information System (INIS)

    Inagaki, Syoichi; Tonami, Syuichi; Yasui, Masakazu; Kuranishi, Makoto; Sugishita, Kouki; Nakamura, Mamoru

    1994-01-01

    Sequential abdominal scintigrams with 99m Tc-labelled red blood cells (RBC) were subtracted for observing a site of gastrointestinal bleeding and calculating the bleeding rate. This method is technically very easy and can detect the site of bleeding with the minimum rate, as low as 0.2 ml/min., in a phantom experiment. In 23 cases with final diagnosis of gastrointestinal bleeding, conventional non-subtraction scintigraphy detected only 30% (7/23), but subtraction scintigraphy detected 61% (14/23). It was concluded that subtraction scintigraphy had higher sensitivity than conventional scintigraphy for early diagnosing bleeding. A combination of non-subtraction and subtraction scintigraphy is recommended to detect a site of gastrointestinal bleeding in a clinical setting. (author)

  14. Comparison of iodine K-edge subtraction and fluorescence subtraction imaging in an animal system

    International Nuclear Information System (INIS)

    Zhang, H.; Zhu, Y.; Bewer, B.; Zhang, L.; Korbas, M.; Pickering, I.J.; George, G.N.; Gupta, M.; Chapman, D.

    2008-01-01

    K-Edge Subtraction (KES) utilizes the discontinuity in the X-ray absorption across the absorption edge of the selected contrast element and creates an image of the projected density of the contrast element from two images acquired just above and below the K-edge of the contrast element. KES has proved to be powerful in coronary angiography, micro-angiography, bronchography, and lymphatic imaging. X-ray fluorescence imaging is a successful technique for the detection of dilute quantities of elements in specimens. However, its application at high X-ray energies (e.g. at the iodine K-edge) is complicated by significant Compton background, which may enter the energy window set for the contrast material's fluorescent X-rays. Inspired by KES, Fluorescence Subtraction Imaging (FSI) is a technique for high-energy (>20 keV) fluorescence imaging using two different incident beam energies just above and below the absorption edge of a contrast element (e.g. iodine). The below-edge image can be assumed as a 'background' image, which includes Compton scatter and fluorescence from other elements. The above-edge image will contain nearly identical spectral content as the below-edge image but will contain the additional fluorescence of the contrast element. This imaging method is especially promising with thick objects with dilute contrast materials, significant Compton background, and/or competing fluorescence lines from other materials. A quality factor is developed to facilitate the comparison. The theoretical value of the quality factor sets the upper limit that an imaging method can achieve when the noise is Poisson limited. The measured value of this factor makes two or more imaging methods comparable. Using the Hard X-ray Micro-Analysis (HXMA) beamline at the Canadian Light Source (CLS), the techniques of FSI and KES were critically compared, with reference to radiation dose, image acquisition time, resolution, signal-to-noise ratios, and quality factor

  15. BPHZL-subtraction scheme and axial gauges

    Energy Technology Data Exchange (ETDEWEB)

    Kreuzer, M.; Rebhan, A.; Schweda, M.; Piguet, O.

    1986-03-27

    The application of the BPHZL subtraction scheme to Yang-Mills theories in axial gauges is presented. In the auxillary mass formulation we show the validity of the convergence theorems for subtracted momentum space integrals, and we give the integral formulae necessary for one-loop calculations. (orig.).

  16. Development of digital subtraction system DAR-1200

    International Nuclear Information System (INIS)

    Kawai, Masumi; Shimizu, Yasumitsu; Ozaki, Takeshi; Sawada, Hiroshi; Uzuyama, Kazuhiro; Nishioka, Hiroyuki

    1989-01-01

    Digital subtraction angiography (DSA) has been of widespread use clinically, and it has attracted considerable attention in angiographic examination today. The merits of Shimadzu high resolution digital subtraction system DAR-1200 are reported in this paper. Furthermore, the principle and clinical usefullness of a new method of DSA called the Peak-Hold DSA are explained especially in details. (author)

  17. A method for dynamic subtraction MR imaging of the liver

    Directory of Open Access Journals (Sweden)

    Setti Ernesto

    2006-06-01

    Full Text Available Abstract Background Subtraction of Dynamic Contrast-Enhanced 3D Magnetic Resonance (DCE-MR volumes can result in images that depict and accurately characterize a variety of liver lesions. However, the diagnostic utility of subtraction images depends on the extent of co-registration between non-enhanced and enhanced volumes. Movement of liver structures during acquisition must be corrected prior to subtraction. Currently available methods are computer intensive. We report a new method for the dynamic subtraction of MR liver images that does not require excessive computer time. Methods Nineteen consecutive patients (median age 45 years; range 37–67 were evaluated by VIBE T1-weighted sequences (TR 5.2 ms, TE 2.6 ms, flip angle 20°, slice thickness 1.5 mm acquired before and 45s after contrast injection. Acquisition parameters were optimized for best portal system enhancement. Pre and post-contrast liver volumes were realigned using our 3D registration method which combines: (a rigid 3D translation using maximization of normalized mutual information (NMI, and (b fast 2D non-rigid registration which employs a complex discrete wavelet transform algorithm to maximize pixel phase correlation and perform multiresolution analysis. Registration performance was assessed quantitatively by NMI. Results The new registration procedure was able to realign liver structures in all 19 patients. NMI increased by about 8% after rigid registration (native vs. rigid registration 0.073 ± 0.031 vs. 0.078 ± 0.031, n.s., paired t-test and by a further 23% (0.096 ± 0.035 vs. 0.078 ± 0.031, p t-test after non-rigid realignment. The overall average NMI increase was 31%. Conclusion This new method for realigning dynamic contrast-enhanced 3D MR volumes of liver leads to subtraction images that enhance diagnostic possibilities for liver lesions.

  18. Digital subtraction angiography of the heart and lungs

    International Nuclear Information System (INIS)

    Moodie, D.S.; Yiannikas, J.

    1986-01-01

    This book contains 12 chapters. Some of the chapter titles are: Physical Principles of Cardiac Digital Subtraction Angiography, The Use of Intravenous Digital Subtraction Angiography in Evaluating Patients with Complex Congenital Heart Disease, Exercise Intravenous Digital Subtraction Angiograpny, Cardiomyopathic and Cardiac Neoplastic Disease, Digital Subtraction Angiography in the Catheterization Laboratory, and Cardiac Digital Subtraction Angiography - Future Directions

  19. Subtraction of random coincidences in γ-ray spectroscopy: A new approach

    International Nuclear Information System (INIS)

    Pattabiraman, N.S.; Ghugre, S.S.; Basu, S.K.; Garg, U.; Ray, S.; Sinha, A.K.; Zhu, S.

    2006-01-01

    A new analytical method for estimation and subsequent subtraction of random coincidences has been developed. It utilizes the knowledge of the counts in the main diagonal of a background-subtracted symmetric data set for the estimation of the events originating from random coincidences. This procedure has been successfully applied to several data sets. It could be a valuable tool for low-fold data sets, especially for low-cross-section events

  20. Post-Newtonian evolution of massive black hole triplets in galactic nuclei - III. A robust lower limit to the nHz stochastic background of gravitational waves

    Science.gov (United States)

    Bonetti, Matteo; Sesana, Alberto; Barausse, Enrico; Haardt, Francesco

    2018-04-01

    Inspiraling massive black-hole binaries (MBHBs) forming in the aftermath of galaxy mergers are expected to be the loudest gravitational-wave (GW) sources relevant for pulsar-timing arrays (PTAs) at nHz frequencies. The incoherent overlap of signals from a cosmic population of MBHBs gives rise to a stochastic GW background (GWB) with characteristic strain around hc ˜ 10-15 at a reference frequency of 1 yr-1, although uncertainties around this value are large. Current PTAs are piercing into the GW amplitude range predicted by MBHB-population models, but no detection has been reported so far. To assess the future success prospects of PTA experiments, it is therefore important to estimate the minimum GWB level consistent with our current understanding of the formation and evolution of galaxies and massive black holes (MBHs). To this purpose, we couple a semianalytic model of galaxy evolution and an extensive study of the statistical outcome of triple MBH interactions. We show that even in the most pessimistic scenario where all MBHBs stall before entering the GW-dominated regime, triple interactions resulting from subsequent galaxy mergers inevitably drive a considerable fraction of the MBHB population to coalescence. At frequencies relevant for PTA, the resulting GWB is only a factor of 2-to-3 suppressed compared to a fiducial model where binaries are allowed to merge over Gyr timescales. Coupled with current estimates of the expected GWB amplitude range, our findings suggest that the minimum GWB from cosmic MBHBs is unlikely to be lower than hc ˜ 10-16 (at f = 1 yr-1), well within the expected sensitivity of projected PTAs based on future observations with FAST, MeerKAT and SKA.

  1. Post-Newtonian evolution of massive black hole triplets in galactic nuclei - III. A robust lower limit to the nHz stochastic background of gravitational waves

    Science.gov (United States)

    Bonetti, Matteo; Sesana, Alberto; Barausse, Enrico; Haardt, Francesco

    2018-06-01

    Inspiraling massive black hole binaries (MBHBs) forming in the aftermath of galaxy mergers are expected to be the loudest gravitational-wave (GW) sources relevant for pulsar-timing arrays (PTAs) at nHz frequencies. The incoherent overlap of signals from a cosmic population of MBHBs gives rise to a stochastic GW background (GWB) with characteristic strain around hc ˜ 10-15 at a reference frequency of 1 yr-1, although uncertainties around this value are large. Current PTAs are piercing into the GW amplitude range predicted by MBHB-population models, but no detection has been reported so far. To assess the future success prospects of PTA experiments, it is therefore important to estimate the minimum GWB level consistent with our current understanding of the formation and evolution of galaxies and massive black holes (MBHs). To this purpose, we couple a semi-analytic model of galaxy evolution and an extensive study of the statistical outcome of triple MBH interactions. We show that even in the most pessimistic scenario where all MBHBs stall before entering the GW-dominated regime, triple interactions resulting from subsequent galaxy mergers inevitably drive a considerable fraction of the MBHB population to coalescence. At frequencies relevant for PTA, the resulting GWB is only a factor of 2-3 suppressed compared to a fiducial model where binaries are allowed to merge over Gyr time-scales . Coupled with current estimates of the expected GWB amplitude range, our findings suggest that the minimum GWB from cosmic MBHBs is unlikely to be lower than hc ˜ 10-16 (at f = 1 yr-1), well within the expected sensitivity of projected PTAs based on future observations with FAST, MeerKAT, and SKA.

  2. Momentum-subtraction renormalization techniques in curved space-time

    Energy Technology Data Exchange (ETDEWEB)

    Foda, O.

    1987-10-01

    Momentum-subtraction techniques, specifically BPHZ and Zimmermann's Normal Product algorithm, are introduced as useful tools in the study of quantum field theories in the presence of background fields. In a model of a self-interacting massive scalar field, conformally coupled to a general asymptotically-flat curved space-time with a trivial topology, momentum-subtractions are shown to respect invariance under general coordinate transformations. As an illustration, general expressions for the trace anomalies are derived, and checked by explicit evaluation of the purely gravitational contributions in the free field theory limit. Furthermore, the trace of the renormalized energy-momentum tensor is shown to vanish at the Gell-Mann Low eigenvalue as it should.

  3. Momentum-subtraction renormalization techniques in curved space-time

    International Nuclear Information System (INIS)

    Foda, O.

    1987-01-01

    Momentum-subtraction techniques, specifically BPHZ and Zimmermann's Normal Product algorithm, are introduced as useful tools in the study of quantum field theories in the presence of background fields. In a model of a self-interacting massive scalar field, conformally coupled to a general asymptotically-flat curved space-time with a trivial topology, momentum-subtractions are shown to respect invariance under general coordinate transformations. As an illustration, general expressions for the trace anomalies are derived, and checked by explicit evaluation of the purely gravitational contributions in the free field theory limit. Furthermore, the trace of the renormalized energy-momentum tensor is shown to vanish at the Gell-Mann Low eigenvalue as it should

  4. Accessing the diffracted wavefield by coherent subtraction

    Science.gov (United States)

    Schwarz, Benjamin; Gajewski, Dirk

    2017-10-01

    Diffractions have unique properties which are still rarely exploited in common practice. Aside from containing subwavelength information on the scattering geometry or indicating small-scale structural complexity, they provide superior illumination compared to reflections. While diffraction occurs arguably on all scales and in most realistic media, the respective signatures typically have low amplitudes and are likely to be masked by more prominent wavefield components. It has been widely observed that automated stacking acts as a directional filter favouring the most coherent arrivals. In contrast to other works, which commonly aim at steering the summation operator towards fainter contributions, we utilize this directional selection to coherently approximate the most dominant arrivals and subtract them from the data. Supported by additional filter functions which can be derived from wave front attributes gained during the stacking procedure, this strategy allows for a fully data-driven recovery of faint diffractions and makes them accessible for further processing. A complex single-channel field data example recorded in the Aegean sea near Santorini illustrates that the diffracted background wavefield is surprisingly rich and despite the absence of a high channel count can still be detected and characterized, suggesting a variety of applications in industry and academia.

  5. Digital subtraction angiography for breast cancer

    International Nuclear Information System (INIS)

    Tsurumi, Kiyohiko; Okuyama, Nobuo

    1987-01-01

    We performed digital subtraction angiography (DSA) on 42 patients with breast diseases to investigate its efficiency. As a result we came to the following conclusions: 1. The sensitivity was well evaluated in intraarterial digital subtraction angiography (IA-DSA) of breast. 2. IA-DSA could diagnose difficult cases like cancer which had undergone augmentation mammoplasty, or like Paget's disease and others. 3. DSA was a safe examination method. 4. The sensitivity of IA-DSA of breast cancer is superior to intravenous digital subtraction angiography (IV-DSA). (author)

  6. A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the subtraction terms I

    Science.gov (United States)

    Somogyi, Gábor; Trócsányi, Zoltán

    2008-08-01

    In previous articles we outlined a subtraction scheme for regularizing doubly-real emission and real-virtual emission in next-to-next-to-leading order (NNLO) calculations of jet cross sections in electron-positron annihilation. In order to find the NNLO correction these subtraction terms have to be integrated over the factorized unresolved phase space and combined with the two-loop corrections. In this paper we perform the integration of all one-parton unresolved subtraction terms.

  7. Digital subtraction angiography in ischemic cerebrovascular accidents

    Energy Technology Data Exchange (ETDEWEB)

    Manelfe, C.; Bonafe, A.; Ducos de Lahitte, M.; Rascol, A.; Prere, J.; Guiraud, B.; Marc-Vergnes, J.P. (Hopital Purpan, 31 - Toulouse (France))

    1983-12-29

    Recent advances in computer and radiological technology have permitted reassessment of intravenous angiography in the evaluation of cerebrovascular disorders. Although digital subtraction angiography is a relatively new technique, it has rapidly gained a widespread acceptance. It has extended the use of angiography to outpatients and to people in whom conventional angiography is contraindicated. This reliable, safe, and relatively noninvasive technique offers the user two benefits: real-time subtraction and enhanced image quality. The system allows angiographic evaluation of the extracranial and intracranial vessels by means of intravenous injection of contrast material. Extracranial studies clearly demonstrate stenoses and occlusions of the major cervicocephalic arteries. Intracranial studies usually detect major cerebrovascular occlusions and provide insight into the collateral flow patterns. Intravenous digital subtraction angiography permits accurate assessment of cervicocephalic vessels after surgical repair. Although intravenous digital subtraction angiography obviates the need for conventional angiography in many cases, movements from the patients, or superimposition of vascular structures can substantially degrade the quality of the images. Digital subtraction angiography with intra-arterial injection of contrast medium will be contemplated in patients with poor intravenous digital subtraction angiography studies prior to surgery.

  8. Digital subtraction angiography in ischemic cerebrovascular accidents

    International Nuclear Information System (INIS)

    Manelfe, C.; Bonafe, A.; Ducos de Lahitte, M.; Rascol, A.; Prere, J.; Guiraud, B.; Marc-Vergnes, J.P.

    1983-01-01

    Recent advances in computer and radiological technology have permitted reassessment of intravenous angiography in the evaluation of cerebrovascular disorders. Although digital subtraction angiography is a relatively new technique, it has rapidly gained a widespread acceptance. It has extended the use of angiography to outpatients and to people in whom conventional angiography is contraindicated. This reliable, safe, and relatively noninvasive technique offers the user two benefits: real-time subtraction and enhanced image quality. The system allows angiographic evaluation of the extracranial and intracranial vessels by means of intravenous injection of contrast material. Extracranial studies clearly demonstrate stenoses and occlusions of the major cervicocephalic arteries. Intracranial studies usually detect major cerebrovascular occlusions and provide insight into the collateral flow patterns. Intravenous digital subtraction angiography permits accurate assessment of cervicocephalic vessels after surgical repair. Although intravenous digital subtraction angiography obviates the need for conventional angiography in many cases, movements from the patients, or superimposition of vascular structures can substantially degrade the quality of the images. Digital subtraction angiography with intra-arterial injection of contrast medium will be contemplated in patients with poor intravenous digital subtraction angiography studies prior to surgery [fr

  9. Robust procedures in chemometrics

    DEFF Research Database (Denmark)

    Kotwa, Ewelina

    properties of the analysed data. The broad theoretical background of robust procedures was given as a very useful supplement to the classical methods, and a new tool, based on robust PCA, aiming at identifying Rayleigh and Raman scatters in excitation-mission (EEM) data was developed. The results show...

  10. X-ray image subtracting system

    International Nuclear Information System (INIS)

    Wesbey, W.H.; Keyes, G.S.; Georges, J.-P.J.

    1982-01-01

    An X-ray image subtracting system for making low contrast structures in the images more conspicuous is described. An X-ray source projects successive high and low energy X-ray beam pulses through a body and the resultant X-ray images are converted to optical images. Two image pick-up devices such as TV cameras that have synchronously operated shutters receive the alternate images and convert them to corresponding analog video signals. In some embodiments, the analog signals are converted to a matrix of digital pixel signals that are variously processed and subtracted and converted to signals for driving a TV monitor display and analog storage devices. In other embodiments the signals are processed and subtracted in analog form for display. The high and low energy pulses can follow each other immediately so good registration between subtracted images is obtainable even though the anatomy is in motion. The energy levels of the X-ray pulses are chosen to maximize the difference in attenuation between the anatomical structure which is to be subtracted out and that which remains. (author)

  11. Left-right subtraction of brain CT

    International Nuclear Information System (INIS)

    Ishiguchi, Tsuneo; Sakuma, Sadayuki

    1986-01-01

    A new image-processing method to obtain a left-right subtraction image of CT was designed for the automated detection of abnormalities in brain CT. An original CT image was divided in two by a centerline. Then the right half of the image was subtracted from the left half by calculating the absorption value of the pixels on the symmetrical positions against the centerline. The mean and the standard deviation of the absorption value of the pixels in the subtraction image were used as parameters for analysis, and the detectability of abnormal CT findings was evaluated in 100 cases - 50 cases each with normal and abnormal CT. The presence of abnormalities could be diagnosed with a sensitivity of 86 %, a specificity of 90 %, and an overall accuracy of 88 % when the borderline of these parameters between normal and abnormal CT was set at the mean + 2SD in the normal group. As a further analysis, the CT image was subdivided into several areas from a functional or anatomical viewpoint, such as cerebral vascular territories, and the left-right subtraction image of each area was obtained. The possibilities of diagnosing the location of an abnormality and of detecting smaller lesions with this method were shown. Left-right subtraction was considered to be a useful method for the detection of asymmetric abnormalities in the automated diagnosis of brain CT. (author)

  12. Digital subtraction angiography system evaluation with phantoms

    International Nuclear Information System (INIS)

    Wenstrup, R.S.; Sweeney, K.P.; Scholz, F.J.

    1985-01-01

    Advances in digital subtraction angiography imaging demonstrate the need for critical evaluation of the performance of digital subtraction equipment. The design of a phantom set for noninvasive assessment of the imaging quality of digital subtraction equipment is described; components include a remotely controlled transport system and individual patterns to evaluate the contrast and detail properties of the image intensifier, low-contrast sensitivity and resolution of the system, geometric distortion of image, linearity, mechanical and electronic stability of equipment, and effects of bone and bowel gas on iodine perception. The performance of an add-on digital radiographic system is presented, along with radiation exposure levels at the image intensifier for a range of radiographic techniques

  13. Nonenhanced magnetic resonance angiography (MRA) of the calf arteries at 3 Tesla: intraindividual comparison of 3D flow-dependent subtractive MRA and 2D flow-independent non-subtractive MRA.

    Science.gov (United States)

    Knobloch, Gesine; Lauff, Marie-Teres; Hirsch, Sebastian; Schwenke, Carsten; Hamm, Bernd; Wagner, Moritz

    2016-12-01

    To prospectively compare 3D flow-dependent subtractive MRA vs. 2D flow-independent non-subtractive MRA for assessment of the calf arteries at 3 Tesla. Forty-two patients with peripheral arterial occlusive disease underwent nonenhanced MRA of calf arteries at 3 Tesla with 3D flow-dependent subtractive MRA (fast spin echo sequence; 3D-FSE-MRA) and 2D flow-independent non-subtractive MRA (balanced steady-state-free-precession sequence; 2D-bSSFP-MRA). Moreover, all patients underwent contrast-enhanced MRA (CE-MRA) as standard-of-reference. Two readers performed a per-segment evaluation for image quality (4 = excellent to 0 = non-diagnostic) and severity of stenosis. Image quality scores of 2D-bSSFP-MRA were significantly higher compared to 3D-FSE-MRA (medians across readers: 4 vs. 3; p Tesla with significantly higher image quality and diagnostic accuracy compared to 3D flow-dependent subtractive MRA (3D-FSE-MRA). • 2D flow-independent non-subtractive MRA (2D-bSSFP-MRA) is a robust NE-MRA technique at 3T • 2D-bSSFP-MRA outperforms 3D flow-dependent subtractive MRA (3D-FSE-MRA) as NE-MRA of calf arteries • 2D-bSSFP-MRA is a promising alternative to CE-MRA for calf PAOD evaluation.

  14. A simple digital subtraction angiographic instrument

    International Nuclear Information System (INIS)

    Ando, Hiroshi; Kobayashi, Tsuyoshi; Imai, Yutaka; Yanagishita, Akira

    1983-01-01

    A digital subtraction angiographic instrument was manufactured using a conventional x-ray TV for gastrointestinal series and a computer for processing of nuclear medical data. The results of visualization of the aorta and its primary branches were reviewed with demonstrable cases. (Chiba, N.)

  15. Digital subtraction angiography: myths and reality

    International Nuclear Information System (INIS)

    Levin, D.C.

    1984-01-01

    Some of the claims made about digital subtraction angiography (DSA) when it was first developed have turned out to be greatly exaggerated, and some members of the radiologic community have become disillusioned with its capabilities. The author discusses some of the limitations of DSA, and concludes that the advantages of DSA outweigh its limitations

  16. Digital subtraction angiography of carotid bifurcation

    International Nuclear Information System (INIS)

    Vries, A.R. de.

    1984-01-01

    This study demonstrates the reliability of digital subtraction angiography (DSA) by means of intra- and interobserver investigations as well as indicating the possibility of substituting catheterangiography by DSA in the diagnosis of carotid bifurcation. Whenever insufficient information is obtained from the combination of non-invasive investigation and DSA, a catheterangiogram will be necessary. (Auth.)

  17. Development of Shimadzu digital subtraction system

    International Nuclear Information System (INIS)

    Nishioka, Hiroyuki; Shibata, Koichi; Shimizu, Yasumitsu; Shibata, Kenji; Wani, Hidenobu

    1985-01-01

    Shimadzu has recently developed a digital subtraction system. It can perform intra-arterial digital subtraction angiography (DSA) using low concentration of contrast medium, or can visualize arteries with intravenuous injection. It can extremely reduce patient's pain in angiography. Image quality of DSA has been much improved by the development of high quality image amplifiers, improvement of signal-to-noise ratio of the x-ray television unit and the development of digital disk recorders. The peak-hold subtraction method that is now under clinical study presents images of blood vessels as the trace of the flow of contrast medium. The maximum-hold memory where the maximum value of the brightness in some period is stored for every picture element is subtracted from the minimum-hold memory where the minimum value is stored, and thus images of blood vessels can be obtained. Hardware of this method is rather simple and it is expected that the amount of contrast medium may be reduced or x-ray dose of the patient may be decreased. (author)

  18. Digital subtraction angiography: first 900 cases

    International Nuclear Information System (INIS)

    Rodgers, H.

    1984-01-01

    The diagnostic technique of digital subtraction angiography (DSA) is briefly outlined. The operational and technical experiences with a DR-960 DSA system used in the examination of the first 900 cases at St. Thomas' Hospital, London are described. (U.K.)

  19. Radionuclide identification using subtractive clustering method

    International Nuclear Information System (INIS)

    Farias, Marcos Santana; Mourelle, Luiza de Macedo

    2011-01-01

    Radionuclide identification is crucial to planning protective measures in emergency situations. This paper presents the application of a method for a classification system of radioactive elements with a fast and efficient response. To achieve this goal is proposed the application of subtractive clustering algorithm. The proposed application can be implemented in reconfigurable hardware, a flexible medium to implement digital hardware circuits. (author)

  20. 3D temporal subtraction on multislice CT images using nonlinear warping technique

    Science.gov (United States)

    Ishida, Takayuki; Katsuragawa, Shigehiko; Kawashita, Ikuo; Kim, Hyounseop; Itai, Yoshinori; Awai, Kazuo; Li, Qiang; Doi, Kunio

    2007-03-01

    The detection of very subtle lesions and/or lesions overlapped with vessels on CT images is a time consuming and difficult task for radiologists. In this study, we have developed a 3D temporal subtraction method to enhance interval changes between previous and current multislice CT images based on a nonlinear image warping technique. Our method provides a subtraction CT image which is obtained by subtraction of a previous CT image from a current CT image. Reduction of misregistration artifacts is important in the temporal subtraction method. Therefore, our computerized method includes global and local image matching techniques for accurate registration of current and previous CT images. For global image matching, we selected the corresponding previous section image for each current section image by using 2D cross-correlation between a blurred low-resolution current CT image and a blurred previous CT image. For local image matching, we applied the 3D template matching technique with translation and rotation of volumes of interests (VOIs) which were selected in the current and the previous CT images. The local shift vector for each VOI pair was determined when the cross-correlation value became the maximum in the 3D template matching. The local shift vectors at all voxels were determined by interpolation of shift vectors of VOIs, and then the previous CT image was nonlinearly warped according to the shift vector for each voxel. Finally, the warped previous CT image was subtracted from the current CT image. The 3D temporal subtraction method was applied to 19 clinical cases. The normal background structures such as vessels, ribs, and heart were removed without large misregistration artifacts. Thus, interval changes due to lung diseases were clearly enhanced as white shadows on subtraction CT images.

  1. Wilson expansion in the minimal subtraction scheme

    International Nuclear Information System (INIS)

    Smirnov, V.A.

    1989-01-01

    The small distance expansion of the product of composite fields is constructed for an arbitrary renormalization procedure of the type of minimal subtraction scheme. Coefficient functions of the expansion are expressed explicitly through the Green functions of composite fields. The expansion has the explicity finite form: the ultraviolet (UV) divergences of the coefficient functions and composite fields are removed by the initial renormalization procedure while the infrared (IR) divergences in massless diagrams with nonvanishing contribution into the coefficient functions are removed by the R-operation which is the IR part of the R-operation. The latter is the generalization of the dimensional renormalization in the case when both UV and IR divergences are present. To derive the expansion, a ''pre-subtracting operator'' is introduced and formulas of the counter-term technique are exploited

  2. Digital subtraction imaging in cardiac investigations

    International Nuclear Information System (INIS)

    Partridge, J.B.; Dickinson, D.F.

    1984-01-01

    The role of digital subtraction imaging (DSI) in the investigation of heart disease in patients of all ages, including neonates, was evaluated by the addition of a continuous fluoroscopy system to an existing, single-plane catheterisation laboratory. In some situations, DSI provided diagnostic images where conventional radiography could not and, in general, provided images of comparable quality to cineangiography. The total dose of contrast medium was usually less than that which would have been required for biplane cineangiography and the dose of radiation was always less. Digital subtraction imaging can make a significant contribution to the investigation of congenital heart disease and has some useful features in the study of acquired heart disease. (author)

  3. Hardware Implementation of a Bilateral Subtraction Filter

    Science.gov (United States)

    Huertas, Andres; Watson, Robert; Villalpando, Carlos; Goldberg, Steven

    2009-01-01

    A bilateral subtraction filter has been implemented as a hardware module in the form of a field-programmable gate array (FPGA). In general, a bilateral subtraction filter is a key subsystem of a high-quality stereoscopic machine vision system that utilizes images that are large and/or dense. Bilateral subtraction filters have been implemented in software on general-purpose computers, but the processing speeds attainable in this way even on computers containing the fastest processors are insufficient for real-time applications. The present FPGA bilateral subtraction filter is intended to accelerate processing to real-time speed and to be a prototype of a link in a stereoscopic-machine- vision processing chain, now under development, that would process large and/or dense images in real time and would be implemented in an FPGA. In terms that are necessarily oversimplified for the sake of brevity, a bilateral subtraction filter is a smoothing, edge-preserving filter for suppressing low-frequency noise. The filter operation amounts to replacing the value for each pixel with a weighted average of the values of that pixel and the neighboring pixels in a predefined neighborhood or window (e.g., a 9 9 window). The filter weights depend partly on pixel values and partly on the window size. The present FPGA implementation of a bilateral subtraction filter utilizes a 9 9 window. This implementation was designed to take advantage of the ability to do many of the component computations in parallel pipelines to enable processing of image data at the rate at which they are generated. The filter can be considered to be divided into the following parts (see figure): a) An image pixel pipeline with a 9 9- pixel window generator, b) An array of processing elements; c) An adder tree; d) A smoothing-and-delaying unit; and e) A subtraction unit. After each 9 9 window is created, the affected pixel data are fed to the processing elements. Each processing element is fed the pixel value for

  4. Tumor scintigraphy by the method for subtracting the initial image with technetium-99m labeled antibody

    International Nuclear Information System (INIS)

    Karube, Yoshiharu; Katsuno, Kentaro; Ito, Sanae; Matsunaga, Kazuhisa; Takata, Jiro; Kuroki, Masahide; Murakami, Masaaki; Matsuoka, Yuji

    1999-01-01

    The method for subtracting the initial image from the localization image was evaluated for radioimmunoscintigraphy of tumors with technetium-99m (Tc-99m) labeled antibodies. Monoclonal antibodies were parental mouse and mouse-human chimeric antibodies to carcinoembryonic antigen (CEA), designated F11-39 and ChF11-39, respectively, both of which have been found to discriminate CEA in tumor tissues from the CEA-related antigens. After reduction of the intrinsic disulfide bonds, these antibodies were labeled with Tc-99m. In vivo studies were performed on athymic nude mice bearing the human CEA-producing gastric carcinoma xenografts. Though biodistribution results showed selective and progressive accumulation of Tc-99m labeled antibodies at the tumor site, high radioactivity in blood was inappropriate for scintigraphic visualization of the tumors within a few hours. We examined the subtraction of the initial Tc-99m image from the Tc-99m localization image after a few hours. Subtracted images of the same count reflected the in vivo behavior of the Tc-99m radioactivity. The subtracted scintigrams revealed excellent tumor images with no significant extrarenal background. Visualization of the tumor site was dependent on antigen-specific binding and nonspecific exudation. These results demonstrate that a method of subtraction of the initial image may serve as a potentially useful diagnostic method for an abnormal site for agents with a low pharmacokinetic value. (author)

  5. Subleading power corrections for N -jettiness subtractions

    Science.gov (United States)

    Moult, Ian; Rothen, Lorena; Stewart, Iain W.; Tackmann, Frank J.; Zhu, Hua Xing

    2017-04-01

    The N -jettiness observable TN provides a way of describing the leading singular behavior of the N -jet cross section in the τ =TN/Q →0 limit, where Q is a hard interaction scale. We consider subleading-power corrections in the τ ≪1 expansion, and employ soft-collinear effective theory to obtain analytic results for the dominant αsτ ln τ and αs2τ ln3τ subleading terms for thrust in e+e- collisions and 0-jettiness for q q ¯-initiated Drell-Yan-like processes at hadron colliders. These results can be used to significantly improve the numerical accuracy and stability of the N -jettiness subtraction technique for performing fixed-order calculations at next-to-leading order and next-to-next-to-leading order. They reduce the size of missing power corrections in the subtractions by an order of magnitude. We also point out that the precise definition of N -jettiness has an important impact on the size of the power corrections and thus the numerical accuracy of the subtractions. The sometimes employed definition of N -jettiness in the hadronic center-of-mass frame suffers from power corrections that grow exponentially with rapidity, causing the power expansion to deteriorate away from central rapidity. This degradation does not occur for the original N -jettiness definition, which explicitly accounts for the boost of the Born process relative to the frame of the hadronic collision, and has a well-behaved power expansion throughout the entire phase space. Integrated over rapidity, using this N -jettiness definition in the subtractions yields another order of magnitude improvement compared to employing the hadronic-frame definition.

  6. Tomosynthesis applied to digital subtraction angiography

    International Nuclear Information System (INIS)

    Kruger, R.A.; Sedaghati, M.; Roy, D.G.; Liu, P.; Nelson, J.A.; Kubal, W.; Del Rio, P.

    1984-01-01

    This extension of the author's previous work on tomographic digital subtraction angiography (DSA) describes the theory of tomosynthetic DSA image reconstruction techniques. In addition to developing the resolution limits resulting from x-ray exposure length and image intensifier field curvature, the authors describe one method of image formation and show tomosynthetic DSA images of animal and human anatomy. Methods for improving the present technique are discussed

  7. Subtractive Structural Modification of Morpho Butterfly Wings.

    Science.gov (United States)

    Shen, Qingchen; He, Jiaqing; Ni, Mengtian; Song, Chengyi; Zhou, Lingye; Hu, Hang; Zhang, Ruoxi; Luo, Zhen; Wang, Ge; Tao, Peng; Deng, Tao; Shang, Wen

    2015-11-11

    Different from studies of butterfly wings through additive modification, this work for the first time studies the property change of butterfly wings through subtractive modification using oxygen plasma etching. The controlled modification of butterfly wings through such subtractive process results in gradual change of the optical properties, and helps the further understanding of structural optimization through natural evolution. The brilliant color of Morpho butterfly wings is originated from the hierarchical nanostructure on the wing scales. Such nanoarchitecture has attracted a lot of research effort, including the study of its optical properties, its potential use in sensing and infrared imaging, and also the use of such structure as template for the fabrication of high-performance photocatalytic materials. The controlled subtractive processes provide a new path to modify such nanoarchitecture and its optical property. Distinct from previous studies on the optical property of the Morpho wing structure, this study provides additional experimental evidence for the origination of the optical property of the natural butterfly wing scales. The study also offers a facile approach to generate new 3D nanostructures using butterfly wings as the templates and may lead to simpler structure models for large-scale man-made structures than those offered by original butterfly wings. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Sky Subtraction with Fiber-Fed Spectrograph

    Science.gov (United States)

    Rodrigues, Myriam

    2017-09-01

    "Historically, fiber-fed spectrographs had been deemed inadequate for the observation of faint targets, mainly because of the difficulty to achieve high accuracy on the sky subtraction. The impossibility to sample the sky in the immediate vicinity of the target in fiber instruments has led to a commonly held view that a multi-object fibre spectrograph cannot achieve an accurate sky subtraction under 1% contrary to their slit counterpart. The next generation of multi-objects spectrograph at the VLT (MOONS) and the planed MOS for the E-ELT (MOSAIC) are fiber-fed instruments, and are aimed to observed targets fainter than the sky continuum level. In this talk, I will present the state-of-art on sky subtraction strategies and data reduction algorithm specifically developed for fiber-fed spectrographs. I will also present the main results of an observational campaign to better characterise the sky spatial and temporal variations ( in particular the continuum and faint sky lines)."

  9. Robustness of Structures

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2008-01-01

    This paper describes the background of the robustness requirements implemented in the Danish Code of Practice for Safety of Structures and in the Danish National Annex to the Eurocode 0, see (DS-INF 146, 2003), (DS 409, 2006), (EN 1990 DK NA, 2007) and (Sørensen and Christensen, 2006). More...... frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure combined with increased requirements to efficiency in design and execution followed by increased risk of human errors has made the need of requirements to robustness of new structures essential....... According to Danish design rules robustness shall be documented for all structures in high consequence class. The design procedure to document sufficient robustness consists of: 1) Review of loads and possible failure modes / scenarios and determination of acceptable collapse extent; 2) Review...

  10. Robust Scientists

    DEFF Research Database (Denmark)

    Gorm Hansen, Birgitte

    their core i nterests, 2) developing a selfsupply of industry interests by becoming entrepreneurs and thus creating their own compliant industry partner and 3) balancing resources within a larger collective of researchers, thus countering changes in the influx of funding caused by shifts in political...... knowledge", Danish research policy seems to have helped develop politically and economically "robust scientists". Scientific robustness is acquired by way of three strategies: 1) tasting and discriminating between resources so as to avoid funding that erodes academic profiles and push scientists away from...

  11. NNLO jet cross sections by subtraction

    International Nuclear Information System (INIS)

    Somogyi, G.; Bolzoni, P.; Trocsanyi, Z.

    2010-06-01

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of an earlier NNLO subtraction scheme over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state. (orig.)

  12. Digital subtraction angiography of the thoracic aorta

    International Nuclear Information System (INIS)

    Grossman, L.B.; Buonocore, E.; Modic, M.T.; Meaney, T.F.

    1984-01-01

    Forty-three patients with acquired and congenital abnormalities of the thoracic aorta were studied using digital subtraction angiography (DSA) after an intravenous bolus injection of 40 ml of contrast material. Abnormalities studied included coarctation, pseudocoarctation, Marfan syndrome, cervical aorta, double aortic arch, aneurysm, dissection, and tumor. Twenty-four patients also had conventional angiography. DSA was accurate in 95% of cases; in the other 5%, involving patients with acute type I dissection, the coronary arteries could not be seen. The authors concluded that in 92% of their patients, DSA could have replaced the standard aortogram

  13. Digital subtraction angiography of the thoracic aorta

    Energy Technology Data Exchange (ETDEWEB)

    Grossman, L.B.; Buonocore, E.; Modic, M.T.; Meaney, T.F.

    1984-02-01

    Forty-three patients with acquired and congenital abnormalities of the thoracic aorta were studied using digital subtraction angiography (DSA) after an intravenous bolus injection of 40 ml of contrast material. Abnormalities studied included coarctation, pseudocoarctation, Marfan syndrome, cervical aorta, double aortic arch, aneurysm, dissection, and tumor. Twenty-four patients also had conventional angiography. DSA was accurate in 95% of cases; in the other 5%, involving patients with acute type I dissection, the coronary arteries could not be seen. The authors concluded that in 92% of their patients, DSA could have replaced the standard aortogram.

  14. Clinical application of digital subtraction angiography (DSA)

    International Nuclear Information System (INIS)

    Morimoto, Tadashi; Kaku, Suiei; Morikawa, Eiji

    1984-01-01

    Intra-arterial digital subtraction angiography (IA-DSA) by the direct puncture of the carotid artery was described with special reference to its techniques, and cases were presented. This method was safe and painless and could be performed repeatedly. Cerebral angiographic images obtained by this method were either superior or fully compatible to the conventional cerebral angiography. It is therefore of great diagnostic value and can replace the conventional method. Furthermore, since the pretreatment is unnecessary and the time required is short, IA-DSA can be used as an adjuvant method for emergency diagnosis. (Namekawa, K)

  15. Intraarterial digital subtraction angiography in neuroradiology

    International Nuclear Information System (INIS)

    Zeumer, H.

    1987-01-01

    Neuroradiology always could make best use of subtraction methods, due to the relative immobility and constant shape of the skull. Arterial DSA now has extended the potential uses while reducing the patient's radiation exposure, the contrast medium dosage and osmolarity. The considerable cut-back in time required for invasive examination has reduced the risk of diagnostic and therapeutic measures. The advantages consisting of immediate image display with high contrast resolution in most of the diagnostic tasks counterbalance the disadvantage of low focal resolution of the DSA in neuroradiology. Interventional neuroradiology today cannot do without i.a. DSA. (orig.) [de

  16. NNLO jet cross sections by subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Somogyi, G.; Bolzoni, P. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Trocsanyi, Z. [CERN, Geneva (Switzerland)

    2010-06-15

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of an earlier NNLO subtraction scheme over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state. (orig.)

  17. NNLO jet cross sections by subtraction

    CERN Document Server

    Somogyi, Gabor; Trocsanyi, Zoltan

    2010-01-01

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of [1-4], over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.

  18. Parallel decompositions of Mueller matrices and polarimetric subtraction

    Directory of Open Access Journals (Sweden)

    Gil J.J.

    2010-06-01

    Full Text Available From a general formulation of the physically realizable parallel decompositions of the Mueller matrix M of a given depolarizing system, a procedure for determining the set of pure Mueller matrices susceptible to be subtracted from M is presented. This procedure provides a way to check if a given pure Mueller matrix N can be subtracted from M or not. If this check is positive, the value of the relative cross section of the subtracted component is also determined.

  19. Spectral amplitude coding OCDMA using and subtraction technique.

    Science.gov (United States)

    Hasoon, Feras N; Aljunid, S A; Samad, M D A; Abdullah, Mohamad Khazani; Shaari, Sahbudin

    2008-03-20

    An optical decoding technique is proposed for a spectral-amplitude-coding-optical code division multiple access, namely, the AND subtraction technique. The theory is being elaborated and experimental results have been done by comparing a double-weight code against the existing code, Hadamard. We have proved that the and subtraction technique gives better bit error rate performance than the conventional complementary subtraction technique against the received power level.

  20. Updates to Constituent Subtraction in Heavy Ions at CMS

    CERN Document Server

    CMS Collaboration

    2018-01-01

    The latest upgrades and performance of constituent subtraction in 5.02 TeV PbPb collisions is presented. The constituent subtraction is extended through the full tracker acceptance, increasing the rapidity reach of correctly subtracted jets. A modulation in azimuthal angle is added to the subtraction, accounting for flow on an event-by-event basis and improving jet energy resolution. Closure of jet energy scale after corrections and jet energy resolution is shown for R=0.4 and R=0.8 jets, the latter for the first time in CMS Heavy-Ions.

  1. Clinical utility of Gd-DTPA subtraction MR imaging for spinal bone metastasis

    International Nuclear Information System (INIS)

    Ando, Keiichi; Murakami, Masao; Kuroda, Yasumasa

    1993-01-01

    Based on reports that Gd-DTPA contributes to the detection of tumors, we used it in 31 cases (97 lesions) of spinal bone metastases. The result was that Gd-DTPA increased the intensity of tumors and the surrounding bone marrow to almost the same level in 53%. To show the metastases clearly, an existing subtraction command system was utilized. The technique included the pixel-by-pixel method, to obtain a Gd-DTPA T1-weighted image (T1WI) subtracted by the original T1WI. The detectability of the subtraction image was improved up to 96%, but was less than the original T1WI (99%). Because of the different imaging rationale between two methods, a means to assess the quality of diagnosis must be proposed. To check the normal background, the same kind of postprocessing was performed in 21 patients without malignancy. Gd-DTPA prefusion was highest in the paravertebral veins, moderate in muscles and epidural fat, and lowest in the spinal cord, intervertebral disk and bone cortex. Gd-DTPA enhanced subtraction MR imaging provides a new diagnostic tool to detect and to assess bone metastasis. (author)

  2. Big Bang Observer and the neutron-star-binary subtraction problem

    International Nuclear Information System (INIS)

    Cutler, Curt; Harms, Jan

    2006-01-01

    The Big Bang Observer (BBO) is a proposed space-based gravitational-wave (GW) mission designed primarily to search for an inflation-generated GW background in the frequency range ∼10 -1 Hz-1 Hz. The major astrophysical foreground in this range is gravitational radiation from inspiralling compact binaries. This foreground is expected to be much larger than the inflation-generated background, so to accomplish its main goal, BBO must be sensitive enough to identify and subtract out practically all such binaries in the observable universe. It is somewhat subtle to decide whether BBO's current baseline design is sufficiently sensitive for this task, since, at least initially, the dominant noise source impeding identification of any one binary is confusion noise from all the others (rather than instrumental noise). Here we present a self-consistent scheme for deciding whether BBO's baseline design is indeed adequate for subtracting out the binary foreground. We conclude that the current baseline should be sufficient. However, if BBO's sensitivity were degraded by a factor 2 from the current baseline, then its ability to detect an underlying primordial background would depend critically on the value of ρ th , the threshold signal-to-noise ratio marking the boundary between detectable and undetectable sources. If BBO's sensitivity were degraded by a factor 4 from the current baseline, it could not detect a primordial background below Ω GW ∼10 -15 . It is impossible to perfectly subtract out each of the binary inspiral waveforms, so an important question is how to deal with the 'residual' errors in the post-subtraction data stream. We sketch a strategy of 'projecting out' these residual errors, at the cost of some effective bandwidth. We also provide estimates of the sizes of various post-Newtonian effects in the inspiral waveforms that must be accounted for in the BBO analysis

  3. NNLO jet cross sections by subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Somogyi, G.; Bolzoni, P. [DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Trocsanyi, Z. [CERN PH-TH, on leave from University of Debrecen and Institute of Nuclear Research of HAS, H-4001 P.O.Box 51 (Hungary)

    2010-08-15

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of Refs. [G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 06, 024 (2005), (arXiv:hep-ph/0502226); G. Somogyi and Z. Trocsanyi, (2006), (arXiv:hep-ph/0609041); G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 01, 070 (2007), (arXiv:hep-ph/0609042); G. Somogyi and Z. Trocsanyi, JHEP 01, 052 (2007), (arXiv:hep-ph/0609043)] over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.

  4. NNLO jet cross sections by subtraction

    International Nuclear Information System (INIS)

    Somogyi, G.; Bolzoni, P.; Trocsanyi, Z.

    2010-01-01

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of Refs. [G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 06, 024 (2005), (arXiv:hep-ph/0502226); G. Somogyi and Z. Trocsanyi, (2006), (arXiv:hep-ph/0609041); G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 01, 070 (2007), (arXiv:hep-ph/0609042); G. Somogyi and Z. Trocsanyi, JHEP 01, 052 (2007), (arXiv:hep-ph/0609043)] over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.

  5. Myocardial perfusion imaging by digital subtraction angiography

    International Nuclear Information System (INIS)

    Kadowaki, Hiroyuki; Ishikawa, Kinji; Ogai, Toshihiro; Katori, Ryo

    1986-01-01

    Several methods of digital subtraction angiography (DSA) were compared to determine which could better visualize regional myocardial perfusion using coronary angiography in seven patients with myocardial infarction, two with angina pectoris and five with normal coronary arteries. Satisfactory DSA was judged to be achieved if the shape of the heart on the mask film was identical to that on the live film and if both films were exactly superimposed. To obtain an identical mask film in the shape of each live film, both films were selected from the following three phases of the cardiac cycle; 1) at the R wave of the electrocardiogram, 2) 100 msec before the R wave, and 3) 200 msec before the R wave. The last two were superior for obtaining mask and live films which were similar in shape, because the cardiac motion in these phases was relatively small. Using these mask and live films, DSA was performed either with the continuous image mode (CI mode) or the time interval difference mode (TID mode). The overall perfusion of contrast medium through the artery to the vein was adequately visualized using the CI mode. Passage of contrast medium through the artery, capillary and vein was visualized at each phase using TID mode. Subtracted images were displayed and photographed, and the density of the contrast medium was adequate to display contour lines as in a relief map. Using this DSA, it was found that regional perfusion of the contrast medium was not always uniform in normal subjects, depending on the typography of the coronary artery. In all patients with anterior myocardial infarction, low perfusion was observed at the infarcted portion compared to the non-infarcted myocardium. In patients with inferior myocardial infarction, this low perfusion area was not observed because right coronary angiography was not subjected to DSA in this study. (J.P.N.)

  6. [Myocardial perfusion imaging by digital subtraction angiography].

    Science.gov (United States)

    Kadowaki, H; Ishikawa, K; Ogai, T; Katori, R

    1986-03-01

    Several methods of digital subtraction angiography (DSA) were compared to determine which could better visualize regional myocardial perfusion using coronary angiography in seven patients with myocardial infarction, two with angina pectoris and five with normal coronary arteries. Satisfactory DSA was judged to be achieved if the shape of the heart on the mask film was identical to that on the live film and if both films were exactly superimposed. To obtain an identical mask film in the shape of each live film, both films were selected from the following three phases of the cardiac cycle; at the R wave of the electrocardiogram, 100 msec before the R wave, and 200 msec before the R wave. The last two were superior for obtaining mask and live films which were similar in shape, because the cardiac motion in these phases was relatively small. Using these mask and live films, DSA was performed either with the continuous image mode (CI mode) or the time interval difference mode (TID mode). The overall perfusion of contrast medium through the artery to the vein was adequately visualized using the CI mode. Passage of contrast medium through the artery, capillary and vein was visualized at each phase using TID mode. Subtracted images were displayed and photographed, and the density of the contrast medium was adequate to display contour lines as in a relief map. Using this DSA, it was found that regional perfusion of the contrast medium was not always uniform in normal subjects, depending on the typography of the coronary artery.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Tomography of photon-added and photon-subtracted states

    NARCIS (Netherlands)

    Bazrafkan, MR; Man'ko, [No Value

    The purpose of this paper is to introduce symplectic and optical tomograms of photon-added and photon-subtracted quantum states. Explicit relations for the tomograms of photon-added and photon-subtracted squeezed coherent states and squeezed number states are obtained. Generating functions for the

  8. An automated subtraction of NLO EW infrared divergences

    Energy Technology Data Exchange (ETDEWEB)

    Schoenherr, Marek [CERN, Theoretical Physics Department, Geneva (Switzerland)

    2018-02-15

    In this paper a generalisation of the Catani-Seymour dipole subtraction method to next-to-leading order electroweak calculations is presented. All singularities due to photon and gluon radiation off both massless and massive partons in the presence of both massless and massive spectators are accounted for. Particular attention is paid to the simultaneous subtraction of singularities of both QCD and electroweak origin which are present in the next-to-leading order corrections to processes with more than one perturbative order contributing at Born level. Similarly, embedding non-dipole-like photon splittings in the dipole subtraction scheme discussed. The implementation of the formulated subtraction scheme in the framework of the Sherpa Monte-Carlo event generator, including the restriction of the dipole phase space through the α-parameters and expanding its existing subtraction for NLO QCD calculations, is detailed and numerous internal consistency checks validating the obtained results are presented. (orig.)

  9. Temporal subtraction of dual-energy chest radiographs

    International Nuclear Information System (INIS)

    Armato, Samuel G. III; Doshi, Devang J.; Engelmann, Roger; Caligiuri, Philip; MacMahon, Heber

    2006-01-01

    Temporal subtraction and dual-energy imaging are two enhanced radiography techniques that are receiving increased attention in chest radiography. Temporal subtraction is an image processing technique that facilitates the visualization of pathologic change across serial chest radiographic images acquired from the same patient; dual-energy imaging exploits the differential relative attenuation of x-ray photons exhibited by soft-tissue and bony structures at different x-ray energies to generate a pair of images that accentuate those structures. Although temporal subtraction images provide a powerful mechanism for enhancing visualization of subtle change, misregistration artifacts in these images can mimic or obscure abnormalities. The purpose of this study was to evaluate whether dual-energy imaging could improve the quality of temporal subtraction images. Temporal subtraction images were generated from 100 pairs of temporally sequential standard radiographic chest images and from the corresponding 100 pairs of dual-energy, soft-tissue radiographic images. The registration accuracy demonstrated in the resulting temporal subtraction images was evaluated subjectively by two radiologists. The registration accuracy of the soft-tissue-based temporal subtraction images was rated superior to that of the conventional temporal subtraction images. Registration accuracy also was evaluated objectively through an automated method, which achieved an area-under-the-ROC-curve value of 0.92 in the distinction between temporal subtraction images that demonstrated clinically acceptable and clinically unacceptable registration accuracy. By combining dual-energy soft-tissue images with temporal subtraction, misregistration artifacts can be reduced and superior image quality can be obtained

  10. Nonenhanced magnetic resonance angiography (MRA) of the calf arteries at 3 Tesla: intraindividual comparison of 3D flow-dependent subtractive MRA and 2D flow-independent non-subtractive MRA

    Energy Technology Data Exchange (ETDEWEB)

    Knobloch, Gesine; Lauff, Marie-Teres; Hirsch, Sebastian; Hamm, Bernd; Wagner, Moritz [Charite - Universitaetsmedizin Berlin, Department of Radiology, Berlin (Germany); Schwenke, Carsten [SCO:SSiS Statistical Consulting, Berlin (Germany)

    2016-12-15

    To prospectively compare 3D flow-dependent subtractive MRA vs. 2D flow-independent non-subtractive MRA for assessment of the calf arteries at 3 Tesla. Forty-two patients with peripheral arterial occlusive disease underwent nonenhanced MRA of calf arteries at 3 Tesla with 3D flow-dependent subtractive MRA (fast spin echo sequence; 3D-FSE-MRA) and 2D flow-independent non-subtractive MRA (balanced steady-state-free-precession sequence; 2D-bSSFP-MRA). Moreover, all patients underwent contrast-enhanced MRA (CE-MRA) as standard-of-reference. Two readers performed a per-segment evaluation for image quality (4 = excellent to 0 = non-diagnostic) and severity of stenosis. Image quality scores of 2D-bSSFP-MRA were significantly higher compared to 3D-FSE-MRA (medians across readers: 4 vs. 3; p < 0.0001) with lower rates of non-diagnostic vessel segments on 2D-bSSFP-MRA (reader 1: <1 % vs. 15 %; reader 2: 1 % vs. 29 %; p < 0.05). Diagnostic performance of 2D-bSSFP-MRA and 3D-FSE-MRA across readers showed sensitivities of 89 % (214/240) vs. 70 % (168/240), p = 0.0153; specificities: 91 % (840/926) vs. 63 % (585/926), p < 0.0001; and diagnostic accuracies of 90 % (1054/1166) vs. 65 % (753/1166), p < 0.0001. 2D flow-independent non-subtractive MRA (2D-bSSFP-MRA) is a robust nonenhanced MRA technique for assessment of the calf arteries at 3 Tesla with significantly higher image quality and diagnostic accuracy compared to 3D flow-dependent subtractive MRA (3D-FSE-MRA). (orig.)

  11. Cardiac complications of intravenous digital subtraction angiography

    International Nuclear Information System (INIS)

    Neergaard, K.; Dirksen, K.L.; Andersen, I.; Galloee, A.M.; Madsen, E.B.

    1989-01-01

    In a prospective study of 103 patients the incidence of cardiac events during intravenous digital subtraction angiography (i.v. DSA) was investigated. Of 103 patients 17 had known ischaemic heart disease. The examination was performed with an ionic contrast medium, Urografin 76% (sodium megluminediatrizoate), administered by bolus injection into the right atrium. Patients with severe cardiac disease were examined only if the procedure was considered of vital importance. Cardiac events were defined as ST-segment changes of more than 0.1 mV, changes in heart rate of more than 20%, arrhythmias and such symptoms as chest pain and dyspnoea. Ischaemic ST-segment changes during i.v. DSA were observed in approximately 20% of the patients and were not related to the presence of known ischaemic heart disease. Three patients developed angina during the procedure. Among 12 patients with known angina only one patient developed angina during the procedure. In this study chest pain was infrequent (3%), but there was a relative high frequency of ECG changes (20%) not related to patients with ischaemic heart disease only. It is concluded that there is a risk of cardiac events during i.v. DSA, but the risk is not increased in patients with known ischaemic heart disease (if they do not suffer from congestive heart failure) as compared with other patients without known ischaemic heart disease. (orig.)

  12. NNLO jet cross sections by subtraction

    Science.gov (United States)

    Somogyi, G.; Bolzoni, P.; Trócsányi, Z.

    2010-08-01

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of Refs. [G. Somogyi, Z. Trócsányi, and V. Del Duca, JHEP 06, 024 (2005), arXiv:hep-ph/0502226; G. Somogyi and Z. Trócsányi, (2006), arXiv:hep-ph/0609041; G. Somogyi, Z. Trócsányi, and V. Del Duca, JHEP 01, 070 (2007), arXiv:hep-ph/0609042; G. Somogyi and Z. Trócsányi, JHEP 01, 052 (2007), arXiv:hep-ph/0609043] over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.

  13. Accuracy of digital subtraction radiography in combination with a contrast media in assessment of proximal caries depth

    Directory of Open Access Journals (Sweden)

    Farzad Esmaeili

    2008-07-01

    Full Text Available Background and aims. Radiography is used to diagnose the demineralization process and carious lesions; however, conventional radiography and direct digital images do not show these lesions when the amount of demineralization is less than 40%. Digital subtraction radiography has recently been used to improve the diagnostic quality of these lesions. The purpose of this study was to compare the caries depth estimated by digital subtraction radiography in combination with barium sulfate in diagnosing proximal dental caries with histopathologic evaluation. Materials and methods. In this study 30 molars and premolars (24 demineralized lesions with cavity, 8 without cavity were studied. Direct digital images were taken (kVp: 68, mA: 8; t: 0.12 for premolars and t: 0.16 for molars whereas the position of X-ray tube and CCD receptor and teeth was fixed. To prepare the second images 135 gr/L barium sulfate was used. The images obtained with the same exposure and geometry and then subtracted. The depth of the lesions in direct digital and subtracted images were assessed and compared with the depth measured in histopathologic assessments. Results. The mean depths (± SD of the lesions were 1.80 ± 0.77 mm in direct digital radiography, 2.32 ± 0.76 mm in subtracted images after barium sulfate treatment, and 2.51 ± 0.43 mm in histopathologic sections. The statistical difference between direct digital radiography and the other methods was significant (P < 0.05. However, the differences were not statistically significant between subtracted images and histopathologic sections. The average intra-class correlation coefficient was 0.7241 (CI: 95%. Conclusion. The present study has demonstrated that digital subtraction radiography images have the potential to measure the depth of proximal caries with no significant difference with histopathologic evaluation.

  14. Background Material

    DEFF Research Database (Denmark)

    Zandersen, Marianne; Hyytiäinen, Kari; Saraiva, Sofia

    This document serves as a background material to the BONUS Pilot Scenario Workshop, which aims to develop harmonised regional storylines of socio-ecological futures in the Baltic Sea region in a collaborative effort together with other BONUS projects and stakeholders.......This document serves as a background material to the BONUS Pilot Scenario Workshop, which aims to develop harmonised regional storylines of socio-ecological futures in the Baltic Sea region in a collaborative effort together with other BONUS projects and stakeholders....

  15. Longitudinal development of subtraction performance in elementary school.

    Science.gov (United States)

    Artemenko, Christina; Pixner, Silvia; Moeller, Korbinian; Nuerk, Hans-Christoph

    2017-10-05

    A major goal of education in elementary mathematics is the mastery of arithmetic operations. However, research on subtraction is rather scarce, probably because subtraction is often implicitly assumed to be cognitively similar to addition, its mathematical inverse. To evaluate this assumption, we examined the relation between the borrow effect in subtraction and the carry effect in addition, and the developmental trajectory of the borrow effect in children using a choice reaction paradigm in a longitudinal study. In contrast to the carry effect in adults, carry and borrow effects in children were found to be categorical rather than continuous. From grades 3 to 4, children became more proficient in two-digit subtraction in general, but not in performing the borrow operation in particular. Thus, we observed no specific developmental progress in place-value computation, but a general improvement in subtraction procedures. Statement of contribution What is already known on this subject? The borrow operation increases difficulty in two-digit subtraction in adults. The carry effect in addition, as the inverse operation of borrowing, comprises categorical and continuous processing characteristics. What does this study add? In contrast to the carry effect in adults, the borrow and carry effects are categorical in elementary school children. Children generally improve in subtraction performance from grades 3 to 4 but do not progress in place-value computation in particular. © 2017 The British Psychological Society.

  16. Digital contrast subtraction radiography for proximal caries diagnosis

    International Nuclear Information System (INIS)

    Kang, Byung Cheol; Yoon, Suk Ja

    2002-01-01

    To determine whether subtraction images utilizing contrast media can improve the diagnostic performance of proximal caries diagnosis compared to conventional periapical radiographic images. Thirty-six teeth with 57 proximal surfaces were radiographied using a size no.2 RVG-ui sensor (Trophy Radiology, Marne-la-Vallee, France). The teeth immersed in water-soluble contrast media and subtraction images were taken. Each tooth was then sectioned for histologic examination. The digital radiographic images and subtraction images were examined and interpreted by three dentists for proximal caries. The results of the proximal caries diagnosis were then verified with the results of the histologic examination. The proximal caries sensitivity using digital subtraction radiography was significantly higher than simply examining a single digital radiograph. The sensitivity of the proximal dentinal carious lesion when analyzed with the subtraction radiograph and the radiograph together was higher than with the subtraction radiograph or the radiograph alone. The use of subtraction radiography with contrast media may be useful for detecting proximal dentinal carious lesions.

  17. A study on computer-aided diagnosis based on temporal subtraction of sequential chest radiographs (in Japanese)

    International Nuclear Information System (INIS)

    Kano, Akiko

    2001-01-01

    An automated digital image subtraction technique for use with pairs of temporally sequential chest radiographs has been developed to aid radiologists in the detection of interval changes. Automated image registration based on nonlinear geometric warping is performed prior to subtraction in order to deal with complicated radiographic misregistration. Processing includes global matching, to achieve rough registration between the entire lung fields in the two images, and local matching, based on a cross-correlation method, to determine local shift values for a number of small regions. A proper warping of x,y-coordinates is determined by fitting two-dimensional polynomials to the distributions of the shift values. One image is warped and then subtracted from the other. The resultant subtraction images were able to enhance the conspicuity of various types of interval changes. Improved global matching based on a weighted template matching method achieved robust registration even with photofluorographs taken in chest mass screening programs, which had previously presented us with a relatively large number of poor-registration images. The new method was applied to 129 pairs of chest mass screening images, and offered registration accuracy as good as manual global matching. An observer test using 114 cases including 57 lung cancer cases presented better sensitivity and specificity on average compared to conventional comparison readings. In addition, newly developed image processing that eliminates the rib edge artifacts in subtraction images was applied to 26 images having pathological interval changes; results showed the potential for application to automated schemes for the detection of interval change patterns. With its capacity to improve the diagnostic accuracy of chest radiographs, the chest temporal subtraction technique promises to become an important element of computer-aided diagnosis (CAD) systems

  18. Digital subtraction cardiopulmonary angiography using FCR (Fuji computed radiography)

    International Nuclear Information System (INIS)

    Tanimura, Shigeo; Tomoyasu, Hiroshi; Banba, Jiro; Masaki, Mikio; Kanno, Yukio; Abe, Kazuo

    1987-01-01

    Digital subtraction cardiopulmonary angiography using FCR was performed on 46 patients including lung cancer, mediastinal tumor, giant bullous formation and others. The images of digital subtraction for pulmonary artery, pulmonary vein and thoracic aorta were studied by comparing to the conventional pulmonary angiogram. Good images of pulmonary artery due to digital subtraction were obtained in 80 % of the 45 cases. This method needed only half volume of contrast media compared to the conventional for obtaining good images and thus reduced side effect. Therefore this method seems to be an usefull pre-operative examination in various chest diseases, especially in case of lung cancer. (author)

  19. Digital subtraction in gadolinium-enhanced MR imaging of the brain: a method to reduce contrast dosage

    International Nuclear Information System (INIS)

    Chan, J.H.M.; Tsui, E.Y.K.; Chan, C.Y.; Lai, K.F.; Cheung, Y.K.; Wong, K.P.C.; Yuen, M.K.; Chau, L.F.; Fong, D.; Mok, C.K.

    2002-01-01

    The aim of the study was to investigate the feasibility of using digital subtraction in contrast-enhanced MR imaging of the brain to reduce the MR contrast dosage without jeopardizing patient care. Fifty-two patients with intracranial lesions, either intra-axial or extra-axial, detected by computerized tomography were selected for contrast-enhanced MR imaging with half-dose and full-dose of gadopentetate dimeglumine. The half-dose unsubtracted, full-dose unsubtracted, and half-dose subtracted MR images were visually assessed by counting the number of enhancing brain lesions in the images and quantitatively analyzed by computing their lesion contrast-to-background ratios (CBR). The visual conspicuity of the half-dose subtracted MR images was comparable to that of the full-dose unsubtracted MR images (p>0.05), whereas the CBR of the half-dose subtracted images was approximately two to three times higher than that of the full-dose unsubtracted images. The half-dose subtracted T1-weighted spin-echo images might be able to replace the conventional standard-dose T1-weighted spin-echo images in MR imaging of the brain. (orig.)

  20. Background radiation

    International Nuclear Information System (INIS)

    Arnott, D.

    1985-01-01

    The effects of background radiation, whether natural or caused by man's activities, are discussed. The known biological effects of radiation in causing cancers or genetic mutations are explained. The statement that there is a threshold below which there is no risk is examined critically. (U.K.)

  1. Model Checking Timed Automata with Priorities using DBM Subtraction

    DEFF Research Database (Denmark)

    David, Alexandre; Larsen, Kim Guldstrand; Pettersson, Paul

    2006-01-01

    In this paper we describe an extension of timed automata with priorities, and efficient algorithms to compute subtraction on DBMs (difference bounded matrices), needed in symbolic model-checking of timed automata with priorities. The subtraction is one of the few operations on DBMs that result...... in a non-convex set needing sets of DBMs for representation. Our subtraction algorithms are efficient in the sense that the number of generated DBMs is significantly reduced compared to a naive algorithm. The overhead in time is compensated by the gain from reducing the number of resulting DBMs since...... this number affects the performance of symbolic model-checking. The uses of the DBM subtraction operation extend beyond timed automata with priorities. It is also useful for allowing guards on transitions with urgent actions, deadlock checking, and timed games....

  2. Increasing Entanglement between Gaussian States by Coherent Photon Subtraction

    DEFF Research Database (Denmark)

    Ourjoumtsev, Alexei; Dantan, Aurelien Romain; Tualle Brouri, Rosa

    2007-01-01

    We experimentally demonstrate that the entanglement between Gaussian entangled states can be increased by non-Gaussian operations. Coherent subtraction of single photons from Gaussian quadrature-entangled light pulses, created by a nondegenerate parametric amplifier, produces delocalized states...

  3. Digital subtraction angiography in patients with central vertigo

    International Nuclear Information System (INIS)

    Inamori, Toru; Takayasu, Yukio; Umetani, Yoshio; Taruoka, Akinori.

    1985-01-01

    Digital subtraction angiography (DSA) is a recently developed non-invasive intravenous angiography which has become possible through real time digital subtraction of x-ray transmission data from an image intensifier and television system. The output signals of the image intensifier-television camera system are digitized by an analog-digital converter. The digital information, 512x512 pixels and 9 bits deep, is fed into the image processing assembly after logarithmic amplification, where 2-8 frames are added and subtracted from mask images for the final digital images. Intravenous digital subtraction angiography was performed in 21 patients with intractable dizzy spells of central origin resistant to treatment. These patients showed some signs of CNS disturbance, although there were no significant findings on CT scans. Surprisingly, findings were abnormal in 14 of 21 patients (66.7%). DSA is, therefore, considered to be an important aid in the diagnosis of vertigo of the central type. (J.P.N.)

  4. Soft-collinear factorization and zero-bin subtractions

    International Nuclear Information System (INIS)

    Chiu Juiyu; Fuhrer, Andreas; Kelley, Randall; Manohar, Aneesh V.; Hoang, Andre H.

    2009-01-01

    We study the Sudakov form factor for a spontaneously broken gauge theory using a (new) Δ-regulator. To be well defined, the effective theory requires zero-bin subtractions for the collinear sectors. The zero-bin subtractions depend on the gauge boson mass M and are not scaleless. They have both finite and 1/ε contributions and are needed to give the correct anomalous dimension and low-scale matching contributions. We also demonstrate the necessity of zero-bin subtractions for soft-collinear factorization. We find that after zero-bin subtractions the form factor is the sum of the collinear contributions minus a soft mass-mode contribution, in agreement with a previous result of Idilbi and Mehen in QCD. This appears to conflict with the method-of-regions approach, where one gets the sum of contributions from different regions.

  5. Digital Subtraction Angiography (DSA) "Road Map": An Angiographic Tool

    Science.gov (United States)

    Turski, P. A.; Stieghorst, M. F.; Strother, C. M.; Crummy, A. B.; Lieberman, R. P.; Mistretta, C. A.

    1982-12-01

    Continuous Digital subtraction combined with intraarterial injections of contrast medium permits the display of arterial structures during real time fluoroscopy. This DSA "road map" facilitates selective catheterization and has proved useful in interventional procedures.

  6. Digital subtraction radiography in the study of moving laryngeal structures

    International Nuclear Information System (INIS)

    Perri, G.; Falaschi, F.; Pieri, L.; Esposito, S.; Ursino, F.

    1988-01-01

    Digital subtraction radiography (DSR) was applied to the study of the larynx in 11 healthy subjects and 15 pathological cases. The method, consisting in the subtraction of images obtained at rest and during phonation or respiratory phases, allowed a clear definition of the normal moving structures - i.e. vocal cords, false cords, pyriform sinuses, thyroid cartilage. Moreover, several pathological conditions could be demonstrated. DSR asserts thus itself as a suitable technique in the functional evaluation of glottis

  7. Decoupling Subtraction Conserving Full Gauge Symmetries : Particles and Fields

    OpenAIRE

    Noriyasu, OHTSUBO; Hideo, MIYATA; Department of Phycics, Kanazawa Technical College; Department of Information Science, Kanazawa Institute of Technolgy

    1984-01-01

    A new subtraction scheme (^^^) which realizes the decoupling and conserves the symmetries of full gauge group simultaneously, is proposed. One particle irreducible Green's functions subtracted by ^^^ reveal the effective low energy symmetries at -p^2≪M^2 and the full symmetries at -p^2≫M^2, where M denotes a heavy mass. Also discussed are conditions in order to carry out ^^^ under two-loop approximation.

  8. AutoDipole - Automated generation of dipole subtraction terms

    International Nuclear Information System (INIS)

    Hasegawa, K.; Uwer, P.

    2009-11-01

    We present an automated generation of the subtraction terms for next-to-leading order QCD calculations in the Catani-Seymour dipole formalism. For a given scattering process with n external particles our Mathematica package generates all dipole terms, allowing for bothmassless and massive dipoles. The numerical evaluation of the subtraction terms proceeds with MadGraph, which provides Fortran code for the necessary scattering amplitudes. Checks of the numerical stability are discussed. (orig.)

  9. Developing a Model to Support Students in Solving Subtraction

    Directory of Open Access Journals (Sweden)

    Nila Mareta Murdiyani

    2013-01-01

    Full Text Available Subtraction has two meanings and each meaning leads to the different strategies. The meaning of “taking away something” suggests a direct subtraction, while the meaning of “determining the difference between two numbers” is more likely to be modeled as indirect addition. Many prior researches found that the second meaning and second strategy rarely appeared in the mathematical textbooks and teacher explanations, including in Indonesia. Therefore, this study was conducted to contribute to the development of a local instruction theory for subtraction by designing instructional activities that can facilitate first grade of primary school students to develop a model in solving two digit numbers subtraction. Consequently, design research was chosen as an appropriate approach for achieving the research aim and Realistic Mathematics Education (RME was used as a guide to design the lesson. This study involved 6 students in the pilot experiment, 31 students in the teaching experiment, and a first grade teacher of SDN 179 Palembang. The  result of this study shows that the beads string could bridge students from the contextual problems (taking ginger candies and making grains bracelets to the use of the empty number line. It also shows that the empty number line could promote students to  use different strategies (direct subtraction, indirect addition, and indirect subtraction in solving subtraction problems. Based on these findings, it is recommended to apply RME in the teaching learning process to make it more meaningful for students. Keywords: Subtraction, Design Research, Realistic Mathematics Education, The Beads String, The Empty Number Line DOI: http://dx.doi.org/10.22342/jme.4.1.567.95-112

  10. Temporal subtraction in chest radiography: Automated assessment of registration accuracy

    International Nuclear Information System (INIS)

    Armato, Samuel G. III; Doshi, Devang J.; Engelmann, Roger; Croteau, Charles L.; MacMahon, Heber

    2006-01-01

    Radiologists routinely compare multiple chest radiographs acquired from the same patient over time to more completely understand changes in anatomy and pathology. While such comparisons are achieved conventionally through a side-by-side display of images, image registration techniques have been developed to combine information from two separate radiographic images through construction of a 'temporal subtraction image'. Although temporal subtraction images provide a powerful mechanism for the enhanced visualization of subtle change, errors in the clinical evaluation of these images may arise from misregistration artifacts that can mimic or obscure pathologic change. We have developed a computerized method for the automated assessment of registration accuracy as demonstrated in temporal subtraction images created from radiographic chest image pairs. The registration accuracy of 150 temporal subtraction images constructed from the computed radiography images of 72 patients was rated manually using a five-point scale ranging from '5-excellent' to '1-poor'; ratings of 3, 4, or 5 reflected clinically acceptable subtraction images, and ratings of 1 or 2 reflected clinically unacceptable images. Gray-level histogram-based features and texture measures are computed at multiple spatial scales within a 'lung mask' region that encompasses both lungs in the temporal subtraction images. A subset of these features is merged through a linear discriminant classifier. With a leave-one-out-by-patient training/testing paradigm, the automated method attained an A z value of 0.92 in distinguishing between temporal subtraction images that demonstrated clinically acceptable and clinically unacceptable registration accuracy. A second linear discriminant classifier yielded an A z value of 0.82 based on a feature subset selected from an independent database of digitized film images. These methods are expected to advance the clinical utility of temporal subtraction images for chest

  11. IR subtraction schemes. Integrating the counterterms at NNLO in QCD

    Energy Technology Data Exchange (ETDEWEB)

    Bolzoni, Paolo; Somogyi, Gabor

    2010-06-15

    We briefly review a subtraction scheme for computing radiative corrections to QCD jet cross sections that can be defined at any order in perturbation theory. Hereafter we discuss the computational methods used to evaluate analytically and numerically the integrated counterterms arising from such a subtraction scheme. Basically these methods the Mellin-Barnes (MB) representations technique together with the harmonic summation and the sector decomposition. (orig.)

  12. IR subtraction schemes. Integrating the counterterms at NNLO in QCD

    International Nuclear Information System (INIS)

    Bolzoni, Paolo; Somogyi, Gabor

    2010-06-01

    We briefly review a subtraction scheme for computing radiative corrections to QCD jet cross sections that can be defined at any order in perturbation theory. Hereafter we discuss the computational methods used to evaluate analytically and numerically the integrated counterterms arising from such a subtraction scheme. Basically these methods the Mellin-Barnes (MB) representations technique together with the harmonic summation and the sector decomposition. (orig.)

  13. AutoDipole - Automated generation of dipole subtraction terms

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, K.; Uwer, P. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Moch, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2009-11-15

    We present an automated generation of the subtraction terms for next-to-leading order QCD calculations in the Catani-Seymour dipole formalism. For a given scattering process with n external particles our Mathematica package generates all dipole terms, allowing for bothmassless and massive dipoles. The numerical evaluation of the subtraction terms proceeds with MadGraph, which provides Fortran code for the necessary scattering amplitudes. Checks of the numerical stability are discussed. (orig.)

  14. Evaluation of sacroiliitis: contrast-enhanced MRI with subtraction technique

    Energy Technology Data Exchange (ETDEWEB)

    Algin, Oktay; Gokalp, Gokhan; Baran, Bulent; Ocakoglu, Gokhan; Yazici, Zeynep [Uludag University, Medical Faculty, Department of Radiology, Gorukle, Bursa (Turkey)

    2009-10-15

    The purpose of the study was to investigate the diagnostic value of contrast-enhanced MRI using the subtraction technique in the detection of active sacroiliitis. Magnetic resonance imaging was performed in 8 asymptomatic volunteers and 50 patients with clinically suspected active sacroiliitis. On precontrast MR images, T1-weighted spin-echo images with and without fat saturation (T1WFS and T1W), STIR and 3D-FLASH images with fat saturation were obtained in the semicoronal plane using a 1.5 Tesla imager. Postcontrast MRI was performed using the same T1WFS sequence as before contrast injection for all volunteers and patients. Postcontrast images were subtracted from fat-suppressed precontrast images. Enhancement within the joint space and bone marrow was considered to demonstrate active sacroiliitis. In 50 patients (100 sacroiliac joints [SIJs]), 40 (76 SIJs) were considered to have active sacroiliitis based on MR images. Bone marrow edema was present in 33 patients (62 SIJs) on STIR images. Routine MRI allowed identification of contrast enhancement in SIJs on postcontrast T1WFS images in 31 patients (49 SIJs). Contrast enhancement was observed in 40 patients (76 SIJs) who were examined by MRI using the subtraction technique. Contrast enhancement was significantly more conspicuous on subtraction images than on non-subtracted postcontrast T1WFS images (Mann-Whitney U test, p<0.001). Contrast-enhanced MRI with subtraction technique may be useful for early detection of active sacroiliitis. (orig.)

  15. Removing ECG Artifact from the Surface EMG Signal Using Adaptive Subtraction Technique

    Science.gov (United States)

    Abbaspour, S; Fallah, A

    2014-01-01

    Background: The electrocardiogram artifact is a major contamination in the electromyogram signals when electromyogram signal is recorded from upper trunk muscles and because of that the contaminated electromyogram is not useful. Objective: Removing electrocardiogram contamination from electromyogram signals. Methods: In this paper, the clean electromyogram signal, electrocardiogram artifact and electrocardiogram signal were recorded from leg muscles, the pectoralis major muscle of the left side and V4, respectively. After the pre-processing, contaminated electromyogram signal is simulated with a combination of clean electromyogram and electrocardiogram artifact. Then, contaminated electromyogram is cleaned using adaptive subtraction method. This method contains some steps; (1) QRS detection, (2) formation of electrocardiogram template by averaging the electrocardiogram complexes, (3) using low pass filter to remove undesirable artifacts, (4) subtraction. Results: Performance of our method is evaluated using qualitative criteria, power spectrum density and coherence and quantitative criteria signal to noise ratio, relative error and cross correlation. The result of signal to noise ratio, relative error and cross correlation is equal to 10.493, 0.04 and %97 respectively. Finally, there is a comparison between proposed method and some existing methods. Conclusion: The result indicates that adaptive subtraction method is somewhat effective to remove electrocardiogram artifact from contaminated electromyogram signal and has an acceptable result. PMID:25505766

  16. Signal-to-noise ratio measurement in parallel MRI with subtraction mapping and consecutive methods

    International Nuclear Information System (INIS)

    Imai, Hiroshi; Miyati, Tosiaki; Ogura, Akio; Doi, Tsukasa; Tsuchihashi, Toshio; Machida, Yoshio; Kobayashi, Masato; Shimizu, Kouzou; Kitou, Yoshihiro

    2008-01-01

    When measuring the signal-to-noise ratio (SNR) of an image the used parallel magnetic resonance imaging, it was confirmed that there was a problem in the application of past SNR measurement. With the method of measuring the noise from the background signal, SNR with parallel imaging was higher than that without parallel imaging. In the subtraction method (NEMA standard), which sets a wide region of interest, the white noise was not evaluated correctly although SNR was close to the theoretical value. We proposed two techniques because SNR in parallel imaging was not uniform according to inhomogeneity of the coil sensitivity distribution and geometry factor. Using the first method (subtraction mapping), two images were scanned with identical parameters. The SNR in each pixel divided the running mean (7 by 7 pixels in neighborhood) by standard deviation/√2 in the same region of interest. Using the second (consecutive) method, more than fifty consecutive scans of the uniform phantom were obtained with identical scan parameters. Then the SNR was calculated from the ratio of mean signal intensity to the standard deviation in each pixel on a series of images. Moreover, geometry factors were calculated from SNRs with and without parallel imaging. The SNR and geometry factor using parallel imaging in the subtraction mapping method agreed with those of the consecutive method. Both methods make it possible to obtain a more detailed determination of SNR in parallel imaging and to calculate the geometry factor. (author)

  17. Digital subtraction angiography for breast diseases

    International Nuclear Information System (INIS)

    Okuyama, Nobuo; Okamoto, Yasushi; Kurita, Minoru; Nonaka, Naomichi; Ozawa, Yoshiyuki; Tsurumi, Kiyohiko

    1986-01-01

    We performed digital subtraction angiography (DSA) via arteries (IA-DSA) and veins (IV-DSA) on 42 patients with breast diseases to investigate its availability. The findings by DSA in cases with breast cancer included: tumor stains, hypervascularity and tortuosity, enlarged blood vessels, encasement and pooling. Metastatic lymph nodes and daughter nodules were also recognized by DSA. In benign tumors of the breast, a tumor stain was observed only in one case of fibroadenoma; otherwise no remarkable changes were noticed. The incidence of signs in cases with breast cancer using IA-DSA was 65 % for hypervascularity, 59 % for tumor stain, 41 % for vascular tortuosity and 41 % for enlargement of vessels. IV-DSA, on the contrary, revealed less incidences. However, tumor stain was seen frequently, and hypervascularity was seldom observed. The number of signs out of the abovementioned six appearing in each case was tabulated. With IA-DSA, there were 5 signs noted in 2 cases, but the majority had fewer: 4 cases in 4 cases and only 2 signs in 4 cases. There were no signs evident in 18 % of the cases. The incidence of the appearance of signs with IV-DSA was lower: there were no signs in 36 % of the cases. Therefore, the diagnostic accuracy of IA-DSA seemed to be fairly good in comparison with that of IV-DSA. The rate of appearance of abnormal signs was also examined, according to the size of the tumors. In IA-DSA, T 1 breast cancers revealed malignant signs in 80 % of the cases, in T 2 there were such signs 75 % and 100 % of the T 3 cases exhibited malignant signs, for an overall average of 82 %. In IV-DSA, T 1 showed 33 %, T 2 showed 70 %, and T 3 , 1 out of 1 case, showed malignant signs, 64 % altogether. It was the bigger the tumor, the larger the number of signs. The smallest breast cancer that exhibited abnormality in DSA was 1.0 x 0.7 cm in size. (J.P.N.)

  18. Motion subtraction of the larynx using digital radiography

    International Nuclear Information System (INIS)

    Kumakawa, Kohzoh; Miyakawa, Kouichi

    1990-01-01

    The development of digital radiography (DR) has made it possible to analyze the contour of the laryngeal soft tissue structures in more detail than the conventional screen-film method. The authors first used the DR system for time subtraction of the larynx during inspiration and phonation. The images are acquired by means of frontal tomography of the larynx using the imaging plate during inspiration and phonation separately, and stored into the memory of the DR system. The thickness of the slices is 5.0 mm. Time subtraction between the mask image during inspiration and the live image during phonation is performed using digital processing on CRT. Superimposing the two images at the upper trachea and the thyroid cartilage of the same depth, makes it possible to measure movement of the vocal cord and false vocal cord quantitatively in three dimensions. The authors named this time subtraction as motion subtraction of the larynx. This motion subtraction image can be obtained by on-line digital processing without complicated development technique, but has so high spatial resolution. This image processing seems to be useful in functional radiographic analysis of laryngeal diseases. (author)

  19. Ictal cerebral perfusion patterns in partial epilepsy: SPECT subtraction

    International Nuclear Information System (INIS)

    Lee, Hyang Woon; Hong, Seung Bong; Tae, Woo Suk; Kim, Sang Eun; Seo, Dae Won; Jeong, Seung Cheol; Yi, Ji Young; Hong, Seung Chyul

    2000-01-01

    To investigate the various ictal perfusion patterns and find the relationships between clinical factors and different perfusion patterns. Interictal and ictal SPECT and SPECT subtraction were performed in 61 patients with partial epilepsy. Both positive images showing ictal hyperperfusion and negative images revealing ictal hypoperfusion were obtained by SPECT subtraction. The ictal perfusion patterns of subtracted SPECT were classified into focal hyperperfusion, hyperperfusion-plus, combined hyperperfusion-hypoperfusion, and focal hypoperfusion only. The concordance rates with epileptic focus were 91.8% in combined analysis of ictal hyperperfusion and hypoperfusion images of subtracted SPECT, 85.2% in hyperperfusion images only of subtracted SPECT, and 68.9% in conventional ictal SPECT analysis. Ictal hypoperfusion occurred less frequently in temporal lobe epilepsy (TLE) than extratemporal lobe epilepsy. Mesial temporal hyperperfusion alone was seen only in mesial TLE while lateral temporal hyperperfusion alone was observed only in neocortical TLE. Hippocampal sclerosis had much lower incidence of ictal hypoperfusion than any other pathology. Some patients showed ictal hypoperfusion at epileptic focus with ictal hyperperfusion in the neighboring brain regions where ictal discharges propagated. Hypoperfusion as well as hyperperfusion in ictal SPECT should be considered for localizing epileptic focus. Although the mechanism of ictal hypoperfusion could be an intra-ictal early exhaustion of seizure focus or a steal phenomenon by the propagation of ictal discharges to adjacent brain areas, further study is needed to elucidate it.=20

  20. Ictal cerebral perfusion patterns in partial epilepsy: SPECT subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyang Woon; Hong, Seung Bong; Tae, Woo Suk; Kim, Sang Eun; Seo, Dae Won; Jeong, Seung Cheol; Yi, Ji Young; Hong, Seung Chyul [Sungkyunkwan Univ. School of Medicine, Seoul (Korea, Republic of)

    2000-06-01

    To investigate the various ictal perfusion patterns and find the relationships between clinical factors and different perfusion patterns. Interictal and ictal SPECT and SPECT subtraction were performed in 61 patients with partial epilepsy. Both positive images showing ictal hyperperfusion and negative images revealing ictal hypoperfusion were obtained by SPECT subtraction. The ictal perfusion patterns of subtracted SPECT were classified into focal hyperperfusion, hyperperfusion-plus, combined hyperperfusion-hypoperfusion, and focal hypoperfusion only. The concordance rates with epileptic focus were 91.8% in combined analysis of ictal hyperperfusion and hypoperfusion images of subtracted SPECT, 85.2% in hyperperfusion images only of subtracted SPECT, and 68.9% in conventional ictal SPECT analysis. Ictal hypoperfusion occurred less frequently in temporal lobe epilepsy (TLE) than extratemporal lobe epilepsy. Mesial temporal hyperperfusion alone was seen only in mesial TLE while lateral temporal hyperperfusion alone was observed only in neocortical TLE. Hippocampal sclerosis had much lower incidence of ictal hypoperfusion than any other pathology. Some patients showed ictal hypoperfusion at epileptic focus with ictal hyperperfusion in the neighboring brain regions where ictal discharges propagated. Hypoperfusion as well as hyperperfusion in ictal SPECT should be considered for localizing epileptic focus. Although the mechanism of ictal hypoperfusion could be an intra-ictal early exhaustion of seizure focus or a steal phenomenon by the propagation of ictal discharges to adjacent brain areas, further study is needed to elucidate it.

  1. Subtraction and dynamic MR images of breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Yoshitaka; Aoki, Manabu; Harada, Junta (Jikei Univ., Tokyo (Japan). School of Medicine)

    1993-04-01

    The purpose of this study was to evaluate the diagnostic effectiveness of subtraction and dynamic MR imaging in patients with breast masses. In 23 breast cancers and six fibroadenomas, spin echo T1 images were obtained at 0.2 Tesla before and every minute after intravenous injection of Gd-DTPA (0.1 or 0.2 mmol/kg). Subtraction images were obtained sequentially on the CRT monitor. All breast masses were enhanced after gadolinium and stood out as bright lesions on subtraction images. The tumor margin and its extension were more precisely evaluated on subtraction MR images than on conventional postcontrast MR images. Breast cancer showed a characteristic time-intensity curve with an early peak, in contrast to fibroadenoma, which showed a gradual increase in signal intensity. Subtraction MR imaging is a simple method for the evaluation of breast masses, and further, the time-intensity curve obtained by dynamic study is helpful in the differential diagnosis of lesions. (author).

  2. Digital subtraction radiographic evaluation of the standardize periapical intraoral radiographs

    International Nuclear Information System (INIS)

    Cho, Bong Hae; Nah, Kyung Soo

    1993-01-01

    The geometrically standardized intraoral radiographs using 5 occlusal registration material were taken serially from immediate, 1 day, 2, 4, 8, 12 and 16 weeks after making the bite blocks. The qualities of those subtracted images were evaluated to check the degree of reproducibility of each impression material. The results were as follows: 1. The standard deviations of the grey scales of the overall subtracted images were 4.9 for Exaflex, 7.2 for Pattern resin, 9.0 for Tooth Shade Acrylic, 12.2 for XCP only, 14.8 for Impregum. 2. The standard deviation of the grey scales of the overall subtracted images were grossly related to those of the localized horizontal line of interest. 3. Exaflex which showed the best subtracted image quality had 15 cases of straight, 14 cases of wave, 1 case of canyon shape. Impregum which showed the worst subtracted image quality had 4 cases of straight, 8 cases of wave, 18 cases of canyon shape respectively.

  3. ECG-gating in non-cardiac digital subtraction angiography

    International Nuclear Information System (INIS)

    Gattoni, F.; Baldini, V.; Cairo, F.

    1987-01-01

    This paper reports the results of the ECG-gating in non-cardiac digital subtraction angiography (DSA). One hundred and fifteen patients underwent DSA (126 examinations); ECG-gating was applied in 66/126 examinations: images recorded at 70% of R wave were subtracted. Artifacts produced by vascular movements were evaluated in all patients: only 40 examinations, carried out whithout ECG-gating, showed vascular artifacts. The major advantage of the ECG-gated DSA is the more efficent subtraction because of the better images superimposition: therefore, ECG-gating can be clinically helpful. On the contrary, it could be a problem in arrhytmic or bradycardic patients. ECG-gating is helpful in DSA imaging of the thoracic and abdominal aorta and of the cervical and renal arteries. In the examinations of peripheral vessels of the limbs it is not so efficent as in the trunk or in the neck

  4. Identification of proteins involved in the functioning of Riftia pachyptila symbiosis by Subtractive Suppression Hybridization

    Directory of Open Access Journals (Sweden)

    Lallier François H

    2007-09-01

    Full Text Available Abstract Background Since its discovery around deep sea hydrothermal vents of the Galapagos Rift about 30 years ago, the chemoautotrophic symbiosis between the vestimentiferan tubeworm Riftia pachyptila and its symbiotic sulfide-oxidizing γ-proteobacteria has been extensively studied. However, studies on the tubeworm host were essentially targeted, biochemical approaches. We decided to use a global molecular approach to identify new proteins involved in metabolite exchanges and assimilation by the host. We used a Subtractive Suppression Hybridization approach (SSH in an unusual way, by comparing pairs of tissues from a single individual. We chose to identify the sequences preferentially expressed in the branchial plume tissue (the only organ in contact with the sea water and in the trophosome (the organ housing the symbiotic bacteria using the body wall as a reference tissue because it is supposedly not involved in metabolite exchanges in this species. Results We produced four cDNA libraries: i body wall-subtracted branchial plume library (BR-BW, ii and its reverse library, branchial plume-subtracted body wall library (BW-BR, iii body wall-subtracted trophosome library (TR-BW, iv and its reverse library, trophosome-subtracted body wall library (BW-TR. For each library, we sequenced about 200 clones resulting in 45 different sequences on average in each library (58 and 59 cDNAs for BR-BW and TR-BW libraries respectively. Overall, half of the contigs matched records found in the databases with good E-values. After quantitative PCR analysis, it resulted that 16S, Major Vault Protein, carbonic anhydrase (RpCAbr, cathepsin and chitinase precursor transcripts were highly represented in the branchial plume tissue compared to the trophosome and the body wall tissues, whereas carbonic anhydrase (RpCAtr, myohemerythrin, a putative T-Cell receptor and one non identified transcript were highly specific of the trophosome tissue. Conclusion Quantitative PCR

  5. Subtractive, divisive and non-monotonic gain control in feedforward nets linearized by noise and delays.

    Science.gov (United States)

    Mejias, Jorge F; Payeur, Alexandre; Selin, Erik; Maler, Leonard; Longtin, André

    2014-01-01

    The control of input-to-output mappings, or gain control, is one of the main strategies used by neural networks for the processing and gating of information. Using a spiking neural network model, we studied the gain control induced by a form of inhibitory feedforward circuitry-also known as "open-loop feedback"-, which has been experimentally observed in a cerebellum-like structure in weakly electric fish. We found, both analytically and numerically, that this network displays three different regimes of gain control: subtractive, divisive, and non-monotonic. Subtractive gain control was obtained when noise is very low in the network. Also, it was possible to change from divisive to non-monotonic gain control by simply modulating the strength of the feedforward inhibition, which may be achieved via long-term synaptic plasticity. The particular case of divisive gain control has been previously observed in vivo in weakly electric fish. These gain control regimes were robust to the presence of temporal delays in the inhibitory feedforward pathway, which were found to linearize the input-to-output mappings (or f-I curves) via a novel variability-increasing mechanism. Our findings highlight the feedforward-induced gain control analyzed here as a highly versatile mechanism of information gating in the brain.

  6. Subtractive, divisive and non-monotonic gain control in feedforward nets linearized by noise and delays

    Directory of Open Access Journals (Sweden)

    Jorge F Mejias

    2014-02-01

    Full Text Available The control of input-to-output mappings, or gain control, is one of the main strategies used by neural networks for the processing and gating of information. Using a spiking neural network model, we studied the gain control induced by a form of inhibitory feedforward circuitry — also known as ’open-loop feedback’ —, which has been experimentally observed in a cerebellum-like structure in weakly electric fish. We found, both analytically and numerically, that this network displays three different regimes of gain control: subtractive, divisive, and non-monotonic. Subtractive gain control was obtained when noise is very low in the network. Also, it was possible to change from divisive to non-monotonic gain control by simply modulating the strength of the feedforward inhibition, which may be achieved via long-term synaptic plasticity. The particular case of divisive gain control has been previously observed in vivo in weakly electric fish. These gain control regimes were robust to the presence of temporal delays in the inhibitory feedforward pathway, which were found to linearize the input-to-output mappings (or f-I curves via a novel variability-increasing mechanism. Our findings highlight the feedforward-induced gain control analyzed here as a highly versatile mechanism of information gating in the brain.

  7. A subtraction pipeline for automatic detection of new appearing multiple sclerosis lesions in longitudinal studies

    Energy Technology Data Exchange (ETDEWEB)

    Ganiler, Onur; Oliver, Arnau; Diez, Yago; Freixenet, Jordi; Llado, Xavier [University of Girona, VICOROB Computer Vision and Robotics Group, Girona (Spain); Vilanova, Joan C. [Girona Magnetic Resonance Center, Girona (Spain); Beltran, Brigitte [Dr. Josep Trueta University Hospital, Institut d' Investigacio Biomedica de Girona, Girona (Spain); Ramio-Torrenta, Lluis [Dr. Josep Trueta University Hospital, Institut d' Investigacio Biomedica de Girona, Multiple Sclerosis and Neuroimmunology Unit, Girona (Spain); Rovira, Alex [Vall d' Hebron University Hospital, Magnetic Resonance Unit, Department of Radiology, Barcelona (Spain)

    2014-05-15

    Time-series analysis of magnetic resonance images (MRI) is of great value for multiple sclerosis (MS) diagnosis and follow-up. In this paper, we present an unsupervised subtraction approach which incorporates multisequence information to deal with the detection of new MS lesions in longitudinal studies. The proposed pipeline for detecting new lesions consists of the following steps: skull stripping, bias field correction, histogram matching, registration, white matter masking, image subtraction, automated thresholding, and postprocessing. We also combine the results of PD-w and T2-w images to reduce false positive detections. Experimental tests are performed in 20 MS patients with two temporal studies separated 12 (12M) or 48 (48M) months in time. The pipeline achieves very good performance obtaining an overall sensitivity of 0.83 and 0.77 with a false discovery rate (FDR) of 0.14 and 0.18 for the 12M and 48M datasets, respectively. The most difficult situation for the pipeline is the detection of very small lesions where the obtained sensitivity is lower and the FDR higher. Our fully automated approach is robust and accurate, allowing detection of new appearing MS lesions. We believe that the pipeline can be applied to large collections of images and also be easily adapted to monitor other brain pathologies. (orig.)

  8. Non-contrast-enhanced MR angiography in critical limb ischemia: performance of quiescent-interval single-shot (QISS) and TSE-based subtraction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Altaha, Mustafa A. [University Health Network, Department of Medical Imaging, Peter Munk Cardiac Centre, Toronto, Ontario (Canada); Jaskolka, Jeffrey D.; Tan, Kongteng; Menezes, Ravi J. [University Health Network, Department of Medical Imaging, Peter Munk Cardiac Centre, Toronto, Ontario (Canada); University of Toronto, Department of Medical Imaging, Toronto, Ontario (Canada); Rick, Manuela; Schmitt, Peter [Siemens Healthcare, Erlangen (Germany); Wintersperger, Bernd J. [University Health Network, Department of Medical Imaging, Peter Munk Cardiac Centre, Toronto, Ontario (Canada); University of Toronto, Department of Medical Imaging, Toronto, Ontario (Canada); Toronto General Hospital, Department of Medical Imaging, Toronto, Ontario (Canada)

    2017-03-15

    The aim of this study was to evaluate diagnostic performance of non-contrast-enhanced 2D quiescent-interval single-shot (QISS) and 3D turbo spin-echo (TSE)-based subtraction magnetic resonance angiography (MRA) in the assessment of peripheral arteries in patients with critical limb ischemia (CLI). Nineteen consecutive patients (74 % male, 72.8 ± 9.9 years) with CLI underwent 2D QISS and 3D TSE-based subtraction MRA at 1.5 T. Axial-overlapping QISS MRA (3 mm/2 mm; 1 x 1 mm{sup 2}) covered from the toes to the aortic bifurcation while coronal 3D TSE-based subtraction MRA (1.3 x 1.2 x 1.3 mm{sup 3}) was restricted to the calf only. MRA data sets (two readers) were evaluated for stenosis (≥50 %) and image quality. Results were compared with digital subtraction angiography (DSA). Two hundred and sixty-seven (267) segments were available for MRA-DSA comparison, with a prevalence of stenosis ≥50 % of 41.9 %. QISS MRA was rated as good to excellent in 79.5-96.0 % of segments without any nondiagnostic segments; 89.8-96.1 % of segments in 3D TSE-based subtraction MRA were rated as nondiagnostic or poor. QISS MRA sensitivities and specificities (segmental) were 92 % and 95 %, respectively, for reader one and 81-97 % for reader two. Due to poor image quality of 3D TSE-based subtraction MRA, diagnostic performance measures were not calculated. QISS MRA demonstrates excellent diagnostic performance and higher robustness than 3D TSE-based subtraction MRA in the challenging patient population with CLI. (orig.)

  9. Non-contrast-enhanced MR angiography in critical limb ischemia: performance of quiescent-interval single-shot (QISS) and TSE-based subtraction techniques

    International Nuclear Information System (INIS)

    Altaha, Mustafa A.; Jaskolka, Jeffrey D.; Tan, Kongteng; Menezes, Ravi J.; Rick, Manuela; Schmitt, Peter; Wintersperger, Bernd J.

    2017-01-01

    The aim of this study was to evaluate diagnostic performance of non-contrast-enhanced 2D quiescent-interval single-shot (QISS) and 3D turbo spin-echo (TSE)-based subtraction magnetic resonance angiography (MRA) in the assessment of peripheral arteries in patients with critical limb ischemia (CLI). Nineteen consecutive patients (74 % male, 72.8 ± 9.9 years) with CLI underwent 2D QISS and 3D TSE-based subtraction MRA at 1.5 T. Axial-overlapping QISS MRA (3 mm/2 mm; 1 x 1 mm 2 ) covered from the toes to the aortic bifurcation while coronal 3D TSE-based subtraction MRA (1.3 x 1.2 x 1.3 mm 3 ) was restricted to the calf only. MRA data sets (two readers) were evaluated for stenosis (≥50 %) and image quality. Results were compared with digital subtraction angiography (DSA). Two hundred and sixty-seven (267) segments were available for MRA-DSA comparison, with a prevalence of stenosis ≥50 % of 41.9 %. QISS MRA was rated as good to excellent in 79.5-96.0 % of segments without any nondiagnostic segments; 89.8-96.1 % of segments in 3D TSE-based subtraction MRA were rated as nondiagnostic or poor. QISS MRA sensitivities and specificities (segmental) were 92 % and 95 %, respectively, for reader one and 81-97 % for reader two. Due to poor image quality of 3D TSE-based subtraction MRA, diagnostic performance measures were not calculated. QISS MRA demonstrates excellent diagnostic performance and higher robustness than 3D TSE-based subtraction MRA in the challenging patient population with CLI. (orig.)

  10. Intravenous digital subtraction angiography of transplanted kidney artery

    International Nuclear Information System (INIS)

    Tessier, J.P; Teyssou, H.; Verdier, J.P.; Tison, E.; Meyblum, J.; Marchal, M.

    1986-01-01

    Results of 351 intravenous digital subtraction angiographs (AN) of transplanted kidneys emphasized reliability of this examination for detection of renal artery stenosis. A prospective study of 219 patients (188 interpretable AN) showed significant stenosis of grafted artery in 22% of cases: 17% of the 126 patients with normal blood pressure and 34% of the 62 cases of hypertension. Digital subtraction allows, with a single injection, assessment of renal artery, nephrogram and excretory cavities, but it is not a substitute for conventional intravenous urography 1 to 2 months after grafting [fr

  11. On a gauge invariant subtraction scheme for massive quantum electrodynamics

    International Nuclear Information System (INIS)

    Abdalla, E.; Gomes, M.; Koeberle, R.

    A momentum-space subtraction scheme for massive quantum electrodynamics is proposed which respects gauge invariance, in contrast to ordinary normal product techniques. As a consequence the dependence of Green functions on the ghost mass becomes very simple and formally gauge invariant normal products of degree up to four, when subtracted according to the proposed scheme, are automatically gauge invariant. As an aplication we discuss the proof of the Adler-Bardeen theorem. Zero mass limits can be taken for Green function after the integration over intermediate states has been carried out [pt

  12. Digital subtraction arthrography of the hips and of the shoulders

    International Nuclear Information System (INIS)

    Fink, B.K.; Schedel, J.; Fink, U.; Hansen, M.; Hilbertz, T.; Hagena, F.W.

    1991-01-01

    In a study on 60 patients, it could be shown that very good results can be achieved in the region of the shoulder joint with the use of the digital subtraction technique and of digital image intensifier radiography. A further possibility of using the digital subtraction technique for proving endoprosthesis loosenings of the hip demonstrated its importance after a short time and has become a routine method in the meantime. These two examination techniques are displayed methodologically and their clinical possibilities of use are assessed in this contribution. (orig.)

  13. Power corrections in the N-jettiness subtraction scheme

    Energy Technology Data Exchange (ETDEWEB)

    Boughezal, Radja [High Energy Physics Division, Argonne National Laboratory,Argonne, IL 60439 (United States); Liu, Xiaohui [Department of Physics, Beijing Normal University,Beijing, 100875 (China); Center of Advanced Quantum Studies, Beijing Normal University,Beijing, 100875 (China); Center for High-Energy Physics, Peking University,Beijing, 100871 (China); Maryland Center for Fundamental Physics, University of Maryland,College Park, MD 20742 (United States); Petriello, Frank [Department of Physics & Astronomy, Northwestern University,Evanston, IL 60208 (United States); High Energy Physics Division, Argonne National Laboratory,Argonne, IL 60439 (United States)

    2017-03-30

    We discuss the leading-logarithmic power corrections in the N-jettiness subtraction scheme for higher-order perturbative QCD calculations. We compute the next-to-leading order power corrections for an arbitrary N-jet process, and we explicitly calculate the power correction through next-to-next-to-leading order for color-singlet production for both qq̄ and gg initiated processes. Our results are compact and simple to implement numerically. Including the leading power correction in the N-jettiness subtraction scheme substantially improves its numerical efficiency. We discuss what features of our techniques extend to processes containing final-state jets.

  14. Analysis of luminosity distributions of strong lensing galaxies: subtraction of diffuse lensed signal

    Science.gov (United States)

    Biernaux, J.; Magain, P.; Hauret, C.

    2017-08-01

    Context. Strong gravitational lensing gives access to the total mass distribution of galaxies. It can unveil a great deal of information about the lenses' dark matter content when combined with the study of the lenses' light profile. However, gravitational lensing galaxies, by definition, appear surrounded by lensed signal, both point-like and diffuse, that is irrelevant to the lens flux. Therefore, the observer is most often restricted to studying the innermost portions of the galaxy, where classical fitting methods show some instabilities. Aims: We aim at subtracting that lensed signal and at characterising some lenses' light profile by computing their shape parameters (half-light radius, ellipticity, and position angle). Our objective is to evaluate the total integrated flux in an aperture the size of the Einstein ring in order to obtain a robust estimate of the quantity of ordinary (luminous) matter in each system. Methods: We are expanding the work we started in a previous paper that consisted in subtracting point-like lensed images and in independently measuring each shape parameter. We improve it by designing a subtraction of the diffuse lensed signal, based only on one simple hypothesis of symmetry. We apply it to the cases where it proves to be necessary. This extra step improves our study of the shape parameters and we refine it even more by upgrading our half-light radius measurement method. We also calculate the impact of our specific image processing on the error bars. Results: The diffuse lensed signal subtraction makes it possible to study a larger portion of relevant galactic flux, as the radius of the fitting region increases by on average 17%. We retrieve new half-light radii values that are on average 11% smaller than in our previous work, although the uncertainties overlap in most cases. This shows that not taking the diffuse lensed signal into account may lead to a significant overestimate of the half-light radius. We are also able to measure

  15. [Affine transformation-based automatic registration for peripheral digital subtraction angiography (DSA)].

    Science.gov (United States)

    Kong, Gang; Dai, Dao-Qing; Zou, Lu-Min

    2008-07-01

    In order to remove the artifacts of peripheral digital subtraction angiography (DSA), an affine transformation-based automatic image registration algorithm is introduced here. The whole process is described as follows: First, rectangle feature templates are constructed with their centers of the extracted Harris corners in the mask, and motion vectors of the central feature points are estimated using template matching technology with the similarity measure of maximum histogram energy. And then the optimal parameters of the affine transformation are calculated with the matrix singular value decomposition (SVD) method. Finally, bilinear intensity interpolation is taken to the mask according to the specific affine transformation. More than 30 peripheral DSA registrations are performed with the presented algorithm, and as the result, moving artifacts of the images are removed with sub-pixel precision, and the time consumption is less enough to satisfy the clinical requirements. Experimental results show the efficiency and robustness of the algorithm.

  16. An analysis of normalization methods for Drosophila RNAi genomic screens and development of a robust validation scheme

    Science.gov (United States)

    Wiles, Amy M.; Ravi, Dashnamoorthy; Bhavani, Selvaraj; Bishop, Alexander J.R.

    2010-01-01

    Genome-wide RNAi screening is a powerful, yet relatively immature technology that allows investigation into the role of individual genes in a process of choice. Most RNAi screens identify a large number of genes with a continuous gradient in the assessed phenotype. Screeners must then decide whether to examine just those genes with the most robust phenotype or to examine the full gradient of genes that cause an effect and how to identify the candidate genes to be validated. We have used RNAi in Drosophila cells to examine viability in a 384-well plate format and compare two screens, untreated control and treatment. We compare multiple normalization methods, which take advantage of different features within the data, including quantile normalization, background subtraction, scaling, cellHTS2 1, and interquartile range measurement. Considering the false-positive potential that arises from RNAi technology, a robust validation method was designed for the purpose of gene selection for future investigations. In a retrospective analysis, we describe the use of validation data to evaluate each normalization method. While no normalization method worked ideally, we found that a combination of two methods, background subtraction followed by quantile normalization and cellHTS2, at different thresholds, captures the most dependable and diverse candidate genes. Thresholds are suggested depending on whether a few candidate genes are desired or a more extensive systems level analysis is sought. In summary, our normalization approaches and experimental design to perform validation experiments are likely to apply to those high-throughput screening systems attempting to identify genes for systems level analysis. PMID:18753689

  17. Methods for robustness programming

    NARCIS (Netherlands)

    Olieman, N.J.

    2008-01-01

    Robustness of an object is defined as the probability that an object will have properties as required. Robustness Programming (RP) is a mathematical approach for Robustness estimation and Robustness optimisation. An example in the context of designing a food product, is finding the best composition

  18. Robustness in laying hens

    NARCIS (Netherlands)

    Star, L.

    2008-01-01

    The aim of the project ‘The genetics of robustness in laying hens’ was to investigate nature and regulation of robustness in laying hens under sub-optimal conditions and the possibility to increase robustness by using animal breeding without loss of production. At the start of the project, a robust

  19. Digital subtraction radiography in the study of the lacrimal system

    International Nuclear Information System (INIS)

    Falaschi, F.; Pieri, L.; Perri, G.; Signorini, G.; Genovese Ebert, F.

    1988-01-01

    The authors emphasize the usefulness of digital dacrycystography (DCG), as compared with various current technoques. Utilizing a radiographic unit equipped with a video-fluoroscopic system and interfaced to a digital video-processor, several digitalized images are acquired before, during and after the injection of contrast medium. Final images are obtained by subtraction of suitable pairs of source frames. Twenty-six patients affected by epiphora have been examined so far. In 21 cases digital subtraction DCG allowed an accurate visualization of the lacrimal system; in the other five patients the amount of information was acceptable. This methodology allows the assessment of both the normal anatomy of the lacrimal passages and their pathological patterns, such as obstructions, stenoses, fistulas, chronic dacrycystites, lacrimal stones. The examination is easy and quick to perform, with no discomfort for the patient. Digital subtraction DCG proves thus to be a very valuable technique thanks to its possible electronic elaboration - i.e. the subtraction and the magnification of images - to its better contrast resolution, and to the possibility it yields of dynamic studies under radioscopic control

  20. Use of digital subtraction angiography for renal transplant evaluation

    International Nuclear Information System (INIS)

    Fanucci, E.; Orlacchio, A.; Pocek, M.; Svegliati, F.

    1986-01-01

    Intravenous digital subtraction angiography (IVDSA) was used to evaluate 6 renal allograft recipients and 3 potential renal donors. In 4 potential renal donors and in 2 allograft recipients, angiographic data were confirmed by surgery. IVDSA is a safe, accurate, easily performed, outpatient procedure; in our opinion DSA should became the procedure of choice to study vascular anatomy in renal transplant evaluation

  1. Summation and subtraction using a modified autoshaping procedure in pigeons.

    Science.gov (United States)

    Ploog, Bertram O

    2008-06-01

    A modified autoshaping paradigm (significantly different from those previously reported in the summation literature) was employed to allow for the simultaneous assessment of stimulus summation and subtraction in pigeons. The response requirements and the probability of food delivery were adjusted such that towards the end of training 12 of 48 trials ended in food delivery, the same proportion as under testing. Stimuli (outlines of squares of three sizes and colors: A, B, and C) were used that could be presented separately or in any combination of two or three stimuli. Twelve of the pigeons (summation groups) were trained with either A, B, and C or with AB, BC, and CA, and tested with ABC. The remaining 12 pigeons (subtraction groups) received training with ABC but were tested with A, B, and C or with AB, BC, and CA. These groups were further subdivided according to whether stimulus elements were presented either in a concentric or dispersed manner. Summation did not occur; subtraction occurred in the two concentric groups. For interpretation of the results, configural theory, the Rescorla-Wagner model, and the composite-stimulus control model were considered. The results suggest different mechanisms responsible for summation and subtraction.

  2. Digital subtraction angiography in the diagnosis of Fallot's tetralogy

    International Nuclear Information System (INIS)

    Ivanitskij, A.V.; Tereshkin, Ya.A.; Sobolev, A.V.; Stolyar, V.L.; Slyunyastikov, M.A.

    1995-01-01

    The authors analyze the efficacy of digital subtraction angiography (DSA) in the diagnosis of Fallot's tetralogy (FT); this method helps simplity and cut down their scope of investigations but does not deteriorate their informative value. DSA findings in 120 patients with TF are analyzed. 5 refs.; 6 figs

  3. Novel Ratio Subtraction and Isoabsorptive Point Methods for ...

    African Journals Online (AJOL)

    Purpose: To develop and validate two innovative spectrophotometric methods used for the simultaneous determination of ambroxol hydrochloride and doxycycline in their binary mixture. Methods: Ratio subtraction and isoabsorptive point methods were used for the simultaneous determination of ambroxol hydrochloride ...

  4. Determination of the kalium-subtracted total beta in food

    International Nuclear Information System (INIS)

    Liu Guofan

    1985-01-01

    A procedure for measuring the kalium-subtracted total beta in food can be applied to estimating the contamination of beta nuclides except 40 K. The procedure, calculating formula, and some experiences in practice are described in this paper. The method is simple, rapid, and very useful to food contamination monitoring

  5. Enriching Addition and Subtraction Fact Mastery through Games

    Science.gov (United States)

    Bay-Williams, Jennifer M.; Kling, Gina

    2014-01-01

    The learning of "basic facts"--single-digit combinations for addition, subtraction, multiplication, and division--has long been a focus of elementary school mathematics. Many people remember completing endless worksheets, timed tests, and flash card drills as they attempted to "master" their basic facts as children. However,…

  6. Dual-energy subtraction radiography of the breast

    International Nuclear Information System (INIS)

    Asaga, Taro; Masuzawa, Chihiro; Kawahara, Satoru; Motohashi, Hisahiko; Okamoto, Takashi; Tamura, Nobuo

    1988-01-01

    Dual-energy projection radiography was applied to breast examination. To perform the dual-energy subtraction radiography using a digital radiography unit, high and low-energy exposures were made at an appropriate time interval under differing X-ray exposure conditions. Dual-energy subtraction radiography was performed in 41 cancer patients in whom the tumor shadow was equivocal or the border of cancer infiltration was not clearly demonstrated by compression mammography, and 15 patients with benign diseases such as fibrocystic disease, cyst and fibroadenoma. In 21 cases out of the 41 cancer patients, the dual-energy subtraction radiography clearly visualized the malignant tumor shadows and the border of cancer infiltration and the daughter nodules by removing the shadows of normal mammary gland. On the other hand, beign diseases such as fibrocystic disease and cyst could be diagnosed as such, because the tumor shadow and the irregularly concentrated image of mammary gland disappeared by the dual-energy subtraction. These results suggest that this new technique will be useful in examination of breast masses. (author)

  7. Dual-energy subtraction radiography of the breast

    Energy Technology Data Exchange (ETDEWEB)

    Asaga, Taro; Masuzawa, Chihiro; Kawahara, Satoru; Motohashi, Hisahiko; Okamoto, Takashi; Tamura, Nobuo

    1988-06-01

    Dual-energy projection radiography was applied to breast examination. To perform the dual-energy subtraction radiography using a digital radiography unit, high and low-energy exposures were made at an appropriate time interval under differing X-ray exposure conditions. Dual-energy subtraction radiography was performed in 41 cancer patients in whom the tumor shadow was equivocal or the border of cancer infiltration was not clearly demonstrated by compression mammography, and 15 patients with benign diseases such as fibrocystic disease, cyst and fibroadenoma. In 21 cases out of the 41 cancer patients, the dual-energy subtraction radiography clearly visualized the malignant tumor shadows and the border of cancer infiltration and the daughter nodules by removing the shadows of normal mammary gland. On the other hand, beign diseases such as fibrocystic disease and cyst could be diagnosed as such, because the tumor shadow and the irregularly concentrated image of mammary gland disappeared by the dual-energy subtraction. These results suggest that this new technique will be useful in examination of breast masses.

  8. New electronic filtering technique in digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Stacul, F; Pozzi-Mucelli, R; Predonzan, F; Magnaldi, S; Godina, G

    1986-01-01

    The authors report their experience with a new electronic filtering technique in digital subtraction angiography (DSA). The principles of the technique are reported and the advantages in comparison with conventional filters are stressed (accurate and fast placement without fluoroscopic exposure). The system provided excellent results in about 900 DSA examinations.

  9. N-jettiness Subtractions for NNLO QCD calculations

    International Nuclear Information System (INIS)

    Gaunt, Jonathan R.; Stahlhofen, Maximilian; Tackmann, Frank J.; Walsh, Jonathan R.; California Univ., CA

    2015-05-01

    We present a subtraction method utilizing the N-jettiness observable, Τ N , to perform QCD calculations for arbitrary processes at next-to-next-to-leading order (NNLO). Our method employs soft-collinear effective theory (SCET) to determine the IR singular contributions of N-jet cross sections for Τ N → 0, and uses these to construct suitable Τ N -subtractions. The construction is systematic and economic, due to being based on a physical observable. The resulting NNLO calculation is fully differential and in a form directly suitable for combining with resummation and parton showers. We explain in detail the application to processes with an arbitrary number of massless partons at lepton and hadron colliders together with the required external inputs in the form of QCD amplitudes and lower-order calculations. We provide explicit expressions for the Τ N -subtractions at NLO and NNLO. The required ingredients are fully known at NLO, and at NNLO for processes with two external QCD partons. The remaining NNLO ingredient for three or more external partons can be obtained numerically with existing NNLO techniques. As an example, we employ our method to obtain the NNLO rapidity spectrum for Drell-Yan and gluon-fusion Higgs production. We discuss aspects of numerical accuracy and convergence and the practical implementation. We also discuss and comment on possible extensions, such as more-differential subtractions, necessary steps for going to N 3 LO, and the treatment of massive quarks.

  10. Appearance of the canine meninges in subtraction magnetic resonance images.

    Science.gov (United States)

    Lamb, Christopher R; Lam, Richard; Keenihan, Erin K; Frean, Stephen

    2014-01-01

    The canine meninges are not visible as discrete structures in noncontrast magnetic resonance (MR) images, and are incompletely visualized in T1-weighted, postgadolinium images, reportedly appearing as short, thin curvilinear segments with minimal enhancement. Subtraction imaging facilitates detection of enhancement of tissues, hence may increase the conspicuity of meninges. The aim of the present study was to describe qualitatively the appearance of canine meninges in subtraction MR images obtained using a dynamic technique. Images were reviewed of 10 consecutive dogs that had dynamic pre- and postgadolinium T1W imaging of the brain that was interpreted as normal, and had normal cerebrospinal fluid. Image-anatomic correlation was facilitated by dissection and histologic examination of two canine cadavers. Meningeal enhancement was relatively inconspicuous in postgadolinium T1-weighted images, but was clearly visible in subtraction images of all dogs. Enhancement was visible as faint, small-rounded foci compatible with vessels seen end on within the sulci, a series of larger rounded foci compatible with vessels of variable caliber on the dorsal aspect of the cerebral cortex, and a continuous thin zone of moderate enhancement around the brain. Superimposition of color-encoded subtraction images on pregadolinium T1- and T2-weighted images facilitated localization of the origin of enhancement, which appeared to be predominantly dural, with relatively few leptomeningeal structures visible. Dynamic subtraction MR imaging should be considered for inclusion in clinical brain MR protocols because of the possibility that its use may increase sensitivity for lesions affecting the meninges. © 2014 American College of Veterinary Radiology.

  11. Inter- and intra-rater agreement in the assessment of the vascularity of spinal metastases using digital subtraction angiography tumor blush

    DEFF Research Database (Denmark)

    Clausen, Caroline; Dahl, Benny; Frevert, Susanne Christiansen

    2017-01-01

    Background: Preoperative embolization is based on the preoperative digital subtraction angiography (DSA) tumor blush, and as such is considered the “gold standard” for determining tumor vascularity. However, to our knowledge reliability studies evaluating vascularity ratings of DSA tumor blush...

  12. The potential for neurovascular intravenous angiography using K-edge digital subtraction angiography

    International Nuclear Information System (INIS)

    Schueltke, E.; Fiedler, S.; Kelly, M.; Griebel, R.; Juurlink, B.; LeDuc, G.; Esteve, F.; Le Bas, J.-F.; Renier, M.; Nemoz, C.; Meguro, K.

    2005-01-01

    Background: Catheterization of small-caliber blood vessels in the central nervous system can be extremely challenging. Alternatively, intravenous (i.v.) administration of contrast agent is minimally invasive and therefore carries a much lower risk for the patient. With conventional X-ray equipment, volumes of contrast agent that could be safely administered to the patient do not allow acquisition of high-quality images after i.v. injection, because the contrast bolus is extremely diluted by passage through the heart. However, synchrotron-based digital K-edge subtraction angiography does allow acquisition of high-quality images after i.v. administration of relatively small doses of contrast agent. Materials and methods: Eight adult male New Zealand rabbits were used for our experiments. Animals were submitted to both angiography with conventional X-ray equipment and synchrotron-based digital subtraction angiography. Results: With conventional X-ray equipment, no contrast was seen in either cerebral or spinal blood vessels after i.v. injection of iodinated contrast agent. However, using K-edge digital subtraction angiography, as little as 1 ml iodinated contrast agent, when administered as i.v. bolus, yielded images of small-caliber blood vessels in the central nervous system (both brain and spinal cord). Conclusions: If it would be possible to image blood vessels of the same diameter in the central nervous system of human patients, the synchrotron-based technique could yield high-quality images at a significantly lower risk for the patient than conventional X-ray imaging. Images could be acquired where catheterization of feeding blood vessels has proven impossible

  13. Development of background reduced Fresnel phase zone plate

    International Nuclear Information System (INIS)

    Tamari, Yohei; Azechi, Hiroshi

    2004-01-01

    In study of hot and dense plasma, a high spatial resolution (a few microns) x-ray imaging is very important to observe these plasmas. The Fresnel phase zone plate (FPZP) consists of alternately material and transparent circular annuli placed concentrically, which image x rays using diffraction x rays from all annuli. FPZP have imaged 4.7-4.77 keV x rays with 2.2 μm spatial resolution. However FPZP has a problem that background level is comparable to signal level. In subtraction of background, the error of 10% is caused. For the accurate background subtraction, we designed new FPZP, which consist of three β layers of a transparent zone and two material zones. The new design FPZP parameters (thickness of material zones, each zone width) have been optimized, and in that optimum design signal-to-background ratio is 4 times better than conventional two layers FPZP

  14. Danish Requirements for Robustness of Structures

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Christensen, H. H.

    2006-01-01

    . This paper describes the background of the revised robustness requirements implemented in the Danish Code of Practice for Safety of Structures in 2003 [1, 2, 3]. According to the Danish design rules robustness shall be documented for all structures where consequences of failure are serious. This paper...... describes the background of the design procedure in the Danish codes, which shall be followed in order to document sufficient robustness in the following steps: Step 1: review of loads and possible failure modes/scenarios and determination of acceptable collapse extent. Step 2: review of the structural...

  15. The comparative study on diagnostic validity of cerebral aneurysm by computed tomography angiography versus digital subtraction angiography after subarachnoid hemorrhage

    Directory of Open Access Journals (Sweden)

    Masih Saboori

    2011-01-01

    Full Text Available Background: In order to declare the preoperative diagnostic value of brain aneurysms, two radiological modalities, computed tomographic angiography and digital subtraction angiography were compared. Methods: In this descriptive analytic study, diagnostic value of computed tomographic angiography (CTA was com-pared with digital subtraction angiography (DSA. Sensitivity, specificity, positive and negative predictive values were calculated and compared between the two modalities. All data were analyzed with SPSS software, version 16. Results: Mean age of patients was 49.5 ± 9.13 years. 57.9 % of subjects were female. CTA showed 89% sensitivity and 100% specificity whereas DSA demonstrated 74% sensitivity and 100% specificity. Positive predictive value of both methods was 100%, but negative predictive value of CTA and DSA was 85% and 69%, respectively. Conclusions: Based on our data, CTA is a valuable diagnostic modality for detection of brain aneurysm and su-barachnoid hemorrhage.

  16. Cloning the Gravity and Shear Stress Related Genes from MG-63 Cells by Subtracting Hybridization

    Science.gov (United States)

    Zhang, Shu; Dai, Zhong-quan; Wang, Bing; Cao, Xin-sheng; Li, Ying-hui; Sun, Xi-qing

    2008-06-01

    Background The purpose of the present study was to clone the gravity and shear stress related genes from osteoblast-like human osteosarcoma MG-63 cells by subtractive hybridization. Method MG-63 cells were divided into two groups (1G group and simulated microgravity group). After cultured for 60 h in two different gravitational environments, two groups of MG-63 cells were treated with 1.5Pa fluid shear stress (FSS) for 60 min, respectively. The total RNA in cells was isolated. The gravity and shear stress related genes were cloned by subtractive hybridization. Result 200 clones were gained. 30 positive clones were selected using PCR method based on the primers of vector and sequenced. The obtained sequences were analyzed by blast. changes of 17 sequences were confirmed by RT-PCR and these genes are related to cell proliferation, cell differentiation, protein synthesis, signal transduction and apoptosis. 5 unknown genes related to gravity and shear stress were found. Conclusion In this part of our study, our result indicates that simulated microgravity may change the activities of MG-63 cells by inducing the functional alterations of specific genes.

  17. Comparison of the diagnostic accuracy of direct digital radiography system, filtered images, and subtraction radiography

    Directory of Open Access Journals (Sweden)

    Wilton Mitsunari Takeshita

    2013-01-01

    Full Text Available Background: To compare the diagnostic accuracy of three different imaging systems: Direct digital radiography system (DDR-CMOS, four types of filtered images, and a priori and a posteriori registration of digital subtraction radiography (DSR in the diagnosis of proximal defects. Materials and Methods: The teeth were arranged in pairs in 10 blocks of vinyl polysiloxane, and proximal defects were performed with drills of 0.25, 0.5, and 1 mm diameter. Kodak RVG 6100 sensor was used to capture the images. A posteriori DSR registrations were done with Regeemy 0.2.43 and subtraction with Image Tool 3.0. Filtered images were obtained with Kodak Dental Imaging 6.1 software. Images (n = 360 were evaluated by three raters, all experts in dental radiology. Results: Sensitivity and specificity of the area under the receiver operator characteristic (ROC curve (Az were higher for DSR images with all three drills (Az = 0.896, 0.979, and 1.000 for drills 0.25, 0.5, and 1 mm, respectively. The highest values were found for 1-mm drills and the lowest for 0.25-mm drills, with negative filter having the lowest values of all (Az = 0.631. Conclusion: The best method of diagnosis was by using a DSR. The negative filter obtained the worst results. Larger drills showed the highest sensitivity and specificity values of the area under the ROC curve.

  18. Characterization of unknown genetic modifications using high throughput sequencing and computational subtraction

    Directory of Open Access Journals (Sweden)

    Butenko Melinka A

    2009-10-01

    Full Text Available Abstract Background When generating a genetically modified organism (GMO, the primary goal is to give a target organism one or several novel traits by using biotechnology techniques. A GMO will differ from its parental strain in that its pool of transcripts will be altered. Currently, there are no methods that are reliably able to determine if an organism has been genetically altered if the nature of the modification is unknown. Results We show that the concept of computational subtraction can be used to identify transgenic cDNA sequences from genetically modified plants. Our datasets include 454-type sequences from a transgenic line of Arabidopsis thaliana and published EST datasets from commercially relevant species (rice and papaya. Conclusion We believe that computational subtraction represents a powerful new strategy for determining if an organism has been genetically modified as well as to define the nature of the modification. Fewer assumptions have to be made compared to methods currently in use and this is an advantage particularly when working with unknown GMOs.

  19. Perceptual Robust Design

    DEFF Research Database (Denmark)

    Pedersen, Søren Nygaard

    The research presented in this PhD thesis has focused on a perceptual approach to robust design. The results of the research and the original contribution to knowledge is a preliminary framework for understanding, positioning, and applying perceptual robust design. Product quality is a topic...... been presented. Therefore, this study set out to contribute to the understanding and application of perceptual robust design. To achieve this, a state-of-the-art and current practice review was performed. From the review two main research problems were identified. Firstly, a lack of tools...... for perceptual robustness was found to overlap with the optimum for functional robustness and at most approximately 2.2% out of the 14.74% could be ascribed solely to the perceptual robustness optimisation. In conclusion, the thesis have offered a new perspective on robust design by merging robust design...

  20. Bremsstrahlung background and quantitation of thin biological samples

    International Nuclear Information System (INIS)

    Khan, K.M.

    1991-02-01

    An inherent feature of all electron-excited X-ray spectra is the presence of a background upon which the characteristic peaks of interest are superimposed. To extract the x-ray intensity of the characteristics lines of interest, it is necessary to subtract this background, which may be due to both specimen generated Bremsstrahlung and extraneous sources, from a measured x-ray spectrum. Some conventional methods of background subtraction will be briefly reviewed. It has been seen that these conventional methods do not give sufficiently accurate results in biological analysis where the peaks of interest are not well-separated and most of the peaks lie in the region where the background is appreciably curved. An alternative approach of background subtraction for such samples is investigated which involves modelling the background using the currently available knowledge of x-ray physics and energy dispersive detectors. This method is particularly suitable for biological samples as well as other samples having an organic matrix. 6 figs. (author)

  1. Deblurring in digital tomosynthesis by iterative self-layer subtraction

    Science.gov (United States)

    Youn, Hanbean; Kim, Jee Young; Jang, SunYoung; Cho, Min Kook; Cho, Seungryong; Kim, Ho Kyung

    2010-04-01

    Recent developments in large-area flat-panel detectors have made tomosynthesis technology revisited in multiplanar xray imaging. However, the typical shift-and-add (SAA) or backprojection reconstruction method is notably claimed by a lack of sharpness in the reconstructed images because of blur artifact which is the superposition of objects which are out of planes. In this study, we have devised an intuitive simple method to reduce the blur artifact based on an iterative approach. This method repeats a forward and backward projection procedure to determine the blur artifact affecting on the plane-of-interest (POI), and then subtracts it from the POI. The proposed method does not include any Fourierdomain operations hence excluding the Fourier-domain-originated artifacts. We describe the concept of the self-layer subtractive tomosynthesis and demonstrate its performance with numerical simulation and experiments. Comparative analysis with the conventional methods, such as the SAA and filtered backprojection methods, is addressed.

  2. Evaluation of the pulmonary vascular bed by digital subtraction angiography

    International Nuclear Information System (INIS)

    Shikuwa, Masahiro; Asai, Sadahiro; Hara, Shiro; Yamasa, Toshihiko; Miyahara, Yoshiyuki; Hara, Kohei; Nishijima, Kyoji.

    1995-01-01

    We studied the usefulness of digital subtraction angiography for evaluating the pulmonary capillary bed. Four individuals underwent the procedure. One was a healthy volunteer and the others were patients with chronic pulmonary emphysema. During catheterization, an 8 F balloon catheter was manipulated into the right pulmonary artery. A total of 20 ml of contrast material was injected at a rate of 10 ml/sec at full inspiration. In the normal subject, the capillary bed filled homogeneously and no defect was seen. In the patients, the pulmonary artery was nearly normal, but severe defects were observed in the pulmonary capillaries. Contrast resolvability was greater with digital subtraction pulmonary angiography than with pulmonary perfusion scintigraphy or pulmonary arteriography. This technique makes possible the visual evaluation of the pulmonary capillary bed. (author)

  3. Subtraction imaging of the ECG gated cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Tanegashima, K.; Fukui, M.; Hyodo, H.

    1987-05-01

    The subtracting manipulation of contrast-enhanced gated cardiac CT (GCCT) images was experimentally studied with TCT 60A - 30 type (Toshiba) for clinical use, thereby reducing the amount of contrast medium (CM). Initially the optimum relationship between the concentration of CM and its injected velocity was determined using the model of resected canine hearts and in actual dogs. The emphasized good-subtracted images were obtained when the difference of CT values was approximately 40 H.U. between cardiac cavity and myocardium. Such condition was feasible in the use of 25 % Diatrizoic acid and its injected velocity of 0.02 ml/kg/sec. Finally the reduction of the amount of CM by 1/3 became possible in clinical settings. The method is applicable to multi-slice GCCT in various heart diseases.

  4. Digital subtraction angiography in the assessment of cardiovascular disease

    International Nuclear Information System (INIS)

    Harrington, D.P.; Boxt, L.M.

    1985-01-01

    Digital subtraction angiography (DSA) is a new radiographic method for evaluating the cardiovascular system. It represents another in a continuing series of computer-assisted diagnostic imaging modalities. The advantages of this technique are its relatively noninvasive nature combined with diagnostically acceptable angiographic images of a variety of cardiovascular structures. Major clinical applications of DSA include its use in imaging of localized regions of peripheral arterial disease and as a screening procedure in evaluating extracranial carotid and vertebral artery disease and renovascular hypertension. Cardiac applications of DSA include assessment of ventricular function, recognition and quantification of intracardiac shunts, visualization of coronary artery bypass grafts, and the study of complex congenital cardiac malformations. Digital subtraction angiography may also be used to evaluate intracranial aneurysms and vascular tumors

  5. Hybrid intravenous digital subtraction angiography of the carotid bifurcation

    International Nuclear Information System (INIS)

    Burbank, F.H.; Enzmann, D.; Keyes, G.S.; Brody, W.R.

    1984-01-01

    A hybrid digital subtraction angiography technique and noise-reduction algorithm were used to evaluate the carotid bifurcation. Temporal, hybrid, and reduced-noise hybrid images were obtained in right and left anterior oblique projections, and both single- and multiple-frame images were created with each method. The resulting images were graded on a scale of 1 to 5 by three experienced neuroradiologists. Temporal images were preferred over hybrid images. The percentage of nondiagnostic examinations, as agreed upon by two readers, was higher for temporal alone than temporal + hybrid. In addition, also by agreement between two readers, temporal + hybrid images significantly increased the number of bifurcations seen in two views (87%) compared to temporal subtraction alone

  6. Practical applications and methods in performing cardiac digital subtraction angiography

    International Nuclear Information System (INIS)

    Markovic, D.M.; Withrow, S.; Moodie, D.S.

    1986-01-01

    One of the purposes of this book is to outline the utility of digital subtraction angiography (DSA) in common clinical practice. No text has dealt with the actual physical setup of the room or the patient prior and during a digital subtraction angiographic study at rest and with exercise. This chapter outlines the steps commonly used when cardiac DSA is performed on patients in the authors' laboratory. The authors have learned over the last few years the best way to prepare the patient and the equipment and it is hoped that utilizing this experience, other centers may avoid the mistakes the authors have made in the past and develop new techniques for the future

  7. Introduction to the principles of Digital Subtraction Angiography (DSA)

    International Nuclear Information System (INIS)

    Kaplanis, P.

    1997-01-01

    Medical applications of advanced technology have rapidly become more sophisticated and more widespread. The field of diagnostic imaging is by no means an exception. There has been a number of breathtaking developments in the field of medical imaging in recent years. Today higher quality, greater clarity and more minute precision are considered not advantages but necessities. Hence new developments are concentrated in the data acquisition and image processing based on the microprocessor controlled modules interfaced with state of the art radiological imaging equipment. One such development is the subtraction of x-rays vis a computer for better visualization of blood vessels, cavities of the heart and of the coronary and pulmonary vascular system. This procedure is termed Digital Subtraction Angiography (DSA). (author)

  8. Spinal pedicle subtraction osteotomy for fixed sagittal imbalance patients

    Science.gov (United States)

    Hyun, Seung-Jae; Kim, Yongjung J; Rhim, Seung-Chul

    2013-01-01

    In addressing spinal sagittal imbalance through a posterior approach, the surgeon now may choose from among a variety of osteotomy techniques. Posterior column osteotomies such as the facetectomy or Ponte or Smith-Petersen osteotomy provide the least correction, but can be used at multiple levels with minimal blood loss and a lower operative risk. Pedicle subtraction osteotomies provide nearly 3 times the per-level correction of Ponte/Smith-Petersen osteotomies; however, they carry increased technical demands, longer operative time, and greater blood loss and associated significant morbidity, including neurological injury. The literature focusing on pedicle subtraction osteotomy for fixed sagittal imbalance patients is reviewed. The long-term overall outcomes, surgical tips to reduce the complications and suggestions for their proper application are also provided. PMID:24340276

  9. Introduction to the principles of Digital Subtraction Angiography (DSA)

    Energy Technology Data Exchange (ETDEWEB)

    Kaplanis, P [Medical Physics Department, Nicosia General Hospital, Nicosia (Cyprus)

    1998-12-31

    Medical applications of advanced technology have rapidly become more sophisticated and more widespread. The field of diagnostic imaging is by no means an exception. There has been a number of breathtaking developments in the field of medical imaging in recent years. Today higher quality, greater clarity and more minute precision are considered not advantages but necessities. Hence new developments are concentrated in the data acquisition and image processing based on the microprocessor controlled modules interfaced with state of the art radiological imaging equipment. One such development is the subtraction of x-rays vis a computer for better visualization of blood vessels, cavities of the heart and of the coronary and pulmonary vascular system. This procedure is termed Digital Subtraction Angiography (DSA). (author). 5 refs, 3 figs.

  10. Self-mixing differential vibrometer based on electronic channel subtraction

    International Nuclear Information System (INIS)

    Donati, Silvano; Norgia, Michele; Giuliani, Guido

    2006-01-01

    An instrument for noncontact measurement of differential vibrations is developed, based on the self-mixing interferometer. As no reference arm is available in the self-mixing configuration, the differential mode is obtained by electronic subtraction of signals from two (nominally equal) vibrometer channels, taking advantage that channels are servo stabilized and thus insensitive to speckle and other sources of amplitude fluctuation. We show that electronic subtraction is nearly as effective as field superposition. Common-mode suppression is 25-30 dB, the dynamic range (amplitude) is in excess of 100 μm, and the minimum measurable (differential) amplitude is 20 nm on aB=10 kHz bandwidth. The instrument has been used to measure vibrations of two metal samples kept in contact, revealing the hysteresis cycle in the microslip and gross-slip regimes, which are of interest in the study of friction induced vibration damping of gas turbine blades for aircraft applications

  11. Digital subtraction angiography in pediatric cerebrovascular occlusive disease

    International Nuclear Information System (INIS)

    Faerber, E.N.; Griska, L.A.B.; Swartz, J.D.; Capitanio, M.A.; Popky, G.L.

    1984-01-01

    While conventional angiography has been used to demonstrate cerebrovascular occlusive disease in the past, digital subtraction angiography (DSA) is capable of showing progressive vascular involvement with ease, simplicity, and extremely low morbidity, making it particularly well suited for children and outpatients either alone or coordinated with computed tomography. The authors discuss the usefulness and advantages of DSA as demonstrated in 7 infants and children with hemiplegia, 4 of whom had sickle-cell disease

  12. Intravenous digital subtraction angiography investigation of reversible cerebral ischemia

    International Nuclear Information System (INIS)

    Pistolesi, G.F.; Maso, R.; Filosto, L.; Piovan, E.; Morgante, D.; Taddei, G.; Tonegutti, M.; Portuese, A.

    1986-01-01

    The brachio-cephalic, carotid, vertebral and intra-cranial vessels of 497 patients presenting reversible ischemic attacks (R.I.A) were evaluated with venous digital subtraction angiography (V.D.S.A.). Alterations of the vascular wall were observed in 289/497 (58.2%) patients, of whom 60% presented multiple locations (539 lesions): obstruction (12%), stenosis >50% (29%), stenosis 50%. The incidence of vascular lesions was higher (p [fr

  13. Temporal subtraction of chest radiographs compensating pose differences

    Science.gov (United States)

    von Berg, Jens; Dworzak, Jalda; Klinder, Tobias; Manke, Dirk; Kreth, Adrian; Lamecker, Hans; Zachow, Stefan; Lorenz, Cristian

    2011-03-01

    Temporal subtraction techniques using 2D image registration improve the detectability of interval changes from chest radiographs. Although such methods are well known for some time they are not widely used in radiologic practice. The reason is the occurrence of strong pose differences between two acquisitions with a time interval of months to years in between. Such strong perspective differences occur in a reasonable number of cases. They cannot be compensated by available image registration methods and thus mask interval changes to be undetectable. In this paper a method is proposed to estimate a 3D pose difference by the adaptation of a 3D rib cage model to both projections. The difference between both is then compensated for, thus producing a subtraction image with virtually no change in pose. The method generally assumes that no 3D image data is available from the patient. The accuracy of pose estimation is validated with chest phantom images acquired under controlled geometric conditions. A subtle interval change simulated by a piece of plastic foam attached to the phantom becomes visible in subtraction images generated with this technique even at strong angular pose differences like an anterior-posterior inclination of 13 degrees.

  14. Renormalization using the background-field method

    International Nuclear Information System (INIS)

    Ichinose, S.; Omote, M.

    1982-01-01

    Renormalization using the background-field method is examined in detail. The subtraction mechanism of subdivergences is described with reference to multi-loop diagrams and one- and two-loop counter-term formulae are explicitly given. The original one-loop counter-term formula of 't Hooft is thereby improved. The present method of renormalization is far easier to manage than the usual one owing to the fact only gauge-invariant quantities are to be considered when worked in an appropriate gauge. Gravity and Yang-Mills theories are studied as examples. (orig.)

  15. Robust speaker recognition in noisy environments

    CERN Document Server

    Rao, K Sreenivasa

    2014-01-01

    This book discusses speaker recognition methods to deal with realistic variable noisy environments. The text covers authentication systems for; robust noisy background environments, functions in real time and incorporated in mobile devices. The book focuses on different approaches to enhance the accuracy of speaker recognition in presence of varying background environments. The authors examine: (a) Feature compensation using multiple background models, (b) Feature mapping using data-driven stochastic models, (c) Design of super vector- based GMM-SVM framework for robust speaker recognition, (d) Total variability modeling (i-vectors) in a discriminative framework and (e) Boosting method to fuse evidences from multiple SVM models.

  16. Fluorescence molecular tomography in the presence of background fluorescence

    International Nuclear Information System (INIS)

    Soubret, Antoine; Ntziachristos, Vasilis

    2006-01-01

    Fluorescence molecular tomography is an emerging imaging technique that resolves the bio-distribution of engineered fluorescent probes developed for in vivo reporting of specific cellular and sub-cellular targets. The method can detect fluorochromes in picomole amounts or less, imaged through entire animals, but the detection sensitivity and imaging performance drop in the presence of background, non-specific fluorescence. In this study, we carried out a theoretical and an experimental investigation on the effect of background fluorescence on the measured signal and on the tomographic reconstruction. We further examined the performance of three subtraction methods based on physical models of photon propagation, using experimental data on phantoms and small animals. We show that the data pre-processing with subtraction schemes can improve image quality and quantification when non-specific background florescence is present

  17. Robustness of Structural Systems

    DEFF Research Database (Denmark)

    Canisius, T.D.G.; Sørensen, John Dalsgaard; Baker, J.W.

    2007-01-01

    The importance of robustness as a property of structural systems has been recognised following several structural failures, such as that at Ronan Point in 1968,where the consequenceswere deemed unacceptable relative to the initiating damage. A variety of research efforts in the past decades have...... attempted to quantify aspects of robustness such as redundancy and identify design principles that can improve robustness. This paper outlines the progress of recent work by the Joint Committee on Structural Safety (JCSS) to develop comprehensive guidance on assessing and providing robustness in structural...... systems. Guidance is provided regarding the assessment of robustness in a framework that considers potential hazards to the system, vulnerability of system components, and failure consequences. Several proposed methods for quantifying robustness are reviewed, and guidelines for robust design...

  18. Robust multivariate analysis

    CERN Document Server

    J Olive, David

    2017-01-01

    This text presents methods that are robust to the assumption of a multivariate normal distribution or methods that are robust to certain types of outliers. Instead of using exact theory based on the multivariate normal distribution, the simpler and more applicable large sample theory is given.  The text develops among the first practical robust regression and robust multivariate location and dispersion estimators backed by theory.   The robust techniques  are illustrated for methods such as principal component analysis, canonical correlation analysis, and factor analysis.  A simple way to bootstrap confidence regions is also provided. Much of the research on robust multivariate analysis in this book is being published for the first time. The text is suitable for a first course in Multivariate Statistical Analysis or a first course in Robust Statistics. This graduate text is also useful for people who are familiar with the traditional multivariate topics, but want to know more about handling data sets with...

  19. A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the doubly unresolved subtraction terms

    CERN Document Server

    Somogyi, Gabor

    2013-01-01

    We finish the definition of a subtraction scheme for computing NNLO corrections to QCD jet cross sections. In particular, we perform the integration of the soft-type contributions to the doubly unresolved counterterms via the method of Mellin-Barnes representations. With these final ingredients in place, the definition of the scheme is complete and the computation of the regularised doubly virtual contribution to the NNLO cross section becomes feasible.

  20. A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the doubly unresolved subtraction terms

    Science.gov (United States)

    Somogyi, Gábor

    2013-04-01

    We finish the definition of a subtraction scheme for computing NNLO corrections to QCD jet cross sections. In particular, we perform the integration of the soft-type contributions to the doubly unresolved counterterms via the method of Mellin-Barnes representations. With these final ingredients in place, the definition of the scheme is complete and the computation of fully differential rates for electron-positron annihilation into two and three jets at NNLO accuracy becomes feasible.

  1. A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the doubly unresolved subtraction terms

    OpenAIRE

    Somogyi, Gabor

    2013-01-01

    We finish the definition of a subtraction scheme for computing NNLO corrections to QCD jet cross sections. In particular, we perform the integration of the soft-type contributions to the doubly unresolved counterterms via the method of Mellin-Barnes representations. With these final ingredients in place, the definition of the scheme is complete and the computation of fully differential rates for electron-positron annihilation into two and three jets at NNLO accuracy becomes feasible.

  2. Background enhancement in breast MR: Correlation with breast density in mammography and background echotexture in ultrasound

    International Nuclear Information System (INIS)

    Ko, Eun Sook; Lee, Byung Hee; Choi, Hye Young; Kim, Rock Bum; Noh, Woo-Chul

    2011-01-01

    Objective: This study aimed to determine whether background enhancement on MR was related to mammographic breast density or ultrasonographic background echotexture in premenopausal and postmenopausal women. Materials and methods: We studied 142 patients (79 premenopausal, 63 postmenopausal) who underwent mammography, ultrasonography, and breast MR. We reviewed the mammography for overall breast density of the contralateral normal breast according to the four-point scale of the BI-RADS classification. Ultrasound findings were classified as homogeneous or heterogeneous background echotexture according to the BI-RADS lexicon. We rated background enhancement on a contralateral breast MR into four categories based on subtraction images: absent, mild, moderate, and marked. All imaging findings were interpreted independently by two readers without knowledge of menstrual status, imaging findings of other modalities. Results: There were significant differences between the premenopausal and postmenopausal group in distribution of mammographic breast density, ultrasonographic background echotexture, and degree of background enhancement. Regarding the relationship between mammographic density and background enhancement, there was no significant correlation. There was significant relationship between ultrasonographic background echotexture and background enhancement in both premenopausal and postmenopausal groups. Conclusion: There is a significant correlation between ultrasonographic background echotexture and background enhancement in MR regardless of menopausal status. Interpreting breast MR, or scheduling for breast MR of women showing heterogeneous background echotexture needs more caution.

  3. A method of background noise cancellation for SQUID applications

    International Nuclear Information System (INIS)

    He, D F; Yoshizawa, M

    2003-01-01

    When superconducting quantum inference devices (SQUIDs) operate in low-cost shielding or unshielded environments, the environmental background noise should be reduced to increase the signal-to-noise ratio. In this paper we present a background noise cancellation method based on a spectral subtraction algorithm. We first measure the background noise and estimate the noise spectrum using fast Fourier transform (FFT), then we subtract the spectrum of background noise from that of the observed noisy signal and the signal can be reconstructed by inverse FFT of the subtracted spectrum. With this method, the background noise, especially stationary inferences, can be suppressed well and the signal-to-noise ratio can be increased. Using high-T C radio-frequency SQUID gradiometer and magnetometer, we have measured the magnetic field produced by a watch, which was placed 35 cm under a SQUID. After noise cancellation, the signal-to-noise ratio could be greatly increased. We also used this method to eliminate the vibration noise of a cryocooler SQUID

  4. Digital subtraction cerebral angiography by intraarterial injection: comparison with conventional angiography

    International Nuclear Information System (INIS)

    Brant-Zawadzki, M.; Gould, R.; Norman, D.; Newton, T.H.; Lane, B.

    1983-01-01

    For 4 months, a prototype digital subtraction system was used to obtain images of the cerebral vasculature after intraarterial contrast injections. In 12 instances, the intraarterial injections were recorded with both a digital subtraction unit and conventional direct magnification film-screen system. The digital subtraction and conventional film subtraction images were compared and graded for quality and information content by three skilled observers. In addition, quantitative measurements of contrast-detail performance and spatial resolution were obtained on both the digital system and the screen-film imaging chain. In a clinical setting, both the digital subtraction and conventional film-screen systems provided similar quality images and angiographic information. Contrast-detail curves demonstrated that digital subtraction angiography outperformed conventional film technique for low-contrast objects. Digital subtraction angiography also reduced the time required to obtain the angiogram, markedly reduced film cost, and lowered the contrast agent burden

  5. Strong-coupling constant at three loops in momentum subtraction scheme

    International Nuclear Information System (INIS)

    Chetyrkin, K.G.; Russian Academy of Sciences, Moscow; Kniehl, B.A.; Steinhauser, M.

    2008-12-01

    In this paper we compute the three-loop corrections to the β function in a momentum subtraction (MOM) scheme with a massive quark. The calculation is performed in the background field formalism applying asymptotic expansions for small and large momenta. Special emphasis is devoted to the relation between the coupling constant in the MOM and MS schemes as well as their ability to describe the phenomenon of decoupling. It is demonstrated by an explicit comparison that the MS scheme can be consistently used to relate the values of the MOM-scheme strong-coupling constant in the energy regions higher and lower than the massive-quark production threshold. This procedure obviates the necessity to know the full mass dependence of the MOM β function and clearly demonstrates the equivalence of both schemes for the description of physics outside the threshold region. (orig.)

  6. Strong-coupling constant at three loops in momentum subtraction scheme

    Energy Technology Data Exchange (ETDEWEB)

    Chetyrkin, K.G. [Karlsruhe Univ. (T.H.), Karlsruhe Inst. of Technology (KIT) (Germany). Inst. fuer Theoretische Teilchenphysik]|[Russian Academy of Sciences, Moscow (Russian Federation). Inst. for Nuclear Research; Kniehl, B.A. [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Steinhauser, M. [Karlsruhe Univ. (T.H.), Karlsruhe Inst. of Technology (KIT) (Germany). Inst. fuer Theoretische Teilchenphysik

    2008-12-15

    In this paper we compute the three-loop corrections to the {beta} function in a momentum subtraction (MOM) scheme with a massive quark. The calculation is performed in the background field formalism applying asymptotic expansions for small and large momenta. Special emphasis is devoted to the relation between the coupling constant in the MOM and MS schemes as well as their ability to describe the phenomenon of decoupling. It is demonstrated by an explicit comparison that the MS scheme can be consistently used to relate the values of the MOM-scheme strong-coupling constant in the energy regions higher and lower than the massive-quark production threshold. This procedure obviates the necessity to know the full mass dependence of the MOM {beta} function and clearly demonstrates the equivalence of both schemes for the description of physics outside the threshold region. (orig.)

  7. Multi-section CT angiography compared with digital subtraction angiography in diagnosing major arterial hemorrhage in inflammatory pancreatic disease

    International Nuclear Information System (INIS)

    Hyare, Harpreet; Desigan, Sharmini; Nicholl, Helen; Guiney, Michael J.; Brookes, Jocelyn A.; Lees, William R.

    2006-01-01

    Purpose: Major arterial hemorrhage is an uncommon but serious complication of pancreatitis with high morbidity and mortality. Digital subtraction angiography (DSA) has long been the gold standard for the detection of a visceral artery pseudoaneurysm or for the site of active bleeding in patients with pancreatitis. Multi-section CT angiography is a minimally invasive technique which can provide high-resolution and high-contrast images of the arterial lumen and wall, with a much lower risk of complication and morbidity compared to DSA. The aim of this study was to determine the accuracy of multi-section CT angiography for the diagnosis of arterial complications of inflammatory pancreatitic disease. Materials and methods: A retrospective analysis of all patients undergoing visceral angiography for major bleeding as a complication of pancreatitis between 1998 and 2004 was performed. Twenty-nine studies in 25 patients (20 males, 5 females) with a mean age of 50.9 years (range 11-67 years) were identified where multi-section CT angiography was performed in the 24 h preceding the digital subtraction angiogram. Results: Digital subtraction angiography detected a pseudoaneurysm or contrast extravasation in 19 studies and no bleeding was demonstrated in 9 studies. CT angiography correctly identified the site and type of bleeding in 18 of the 19 positive studies. CT angiography detected extravasation of contrast in one study that was not demonstrated on digital subtraction angiography. The sensitivity and specificity for multi-section CT angiography for the detection of major arterial bleeding on a background of pancreatitis were 0.947 and 0.900, respectively. Conclusion: Multi-section CT angiography is a sensitive and accurate technique for the detection of major arterial hemorrhage in inflammatory pancreatic disease and should be considered as the first investigation in the management of these patients

  8. Robustness of Structures

    DEFF Research Database (Denmark)

    Faber, Michael Havbro; Vrouwenvelder, A.C.W.M.; Sørensen, John Dalsgaard

    2011-01-01

    In 2005, the Joint Committee on Structural Safety (JCSS) together with Working Commission (WC) 1 of the International Association of Bridge and Structural Engineering (IABSE) organized a workshop on robustness of structures. Two important decisions resulted from this workshop, namely...... ‘COST TU0601: Robustness of Structures’ was initiated in February 2007, aiming to provide a platform for exchanging and promoting research in the area of structural robustness and to provide a basic framework, together with methods, strategies and guidelines enhancing robustness of structures...... the development of a joint European project on structural robustness under the COST (European Cooperation in Science and Technology) programme and the decision to develop a more elaborate document on structural robustness in collaboration between experts from the JCSS and the IABSE. Accordingly, a project titled...

  9. Robust Growth Determinants

    OpenAIRE

    Doppelhofer, Gernot; Weeks, Melvyn

    2011-01-01

    This paper investigates the robustness of determinants of economic growth in the presence of model uncertainty, parameter heterogeneity and outliers. The robust model averaging approach introduced in the paper uses a flexible and parsi- monious mixture modeling that allows for fat-tailed errors compared to the normal benchmark case. Applying robust model averaging to growth determinants, the paper finds that eight out of eighteen variables found to be significantly related to economic growth ...

  10. Robust Programming by Example

    OpenAIRE

    Bishop , Matt; Elliott , Chip

    2011-01-01

    Part 2: WISE 7; International audience; Robust programming lies at the heart of the type of coding called “secure programming”. Yet it is rarely taught in academia. More commonly, the focus is on how to avoid creating well-known vulnerabilities. While important, that misses the point: a well-structured, robust program should anticipate where problems might arise and compensate for them. This paper discusses one view of robust programming and gives an example of how it may be taught.

  11. Digital subtraction angiography in the evaluation of chemodectomas

    International Nuclear Information System (INIS)

    Vlahos, L.; Papathanasiou, M.; Gouliamos, A.; Dimakakos, P.; Papavassiliou, C.

    1988-01-01

    During the last 2 years eleven patients with surgically confirmed chemodectomas have been investigated by means of digital subtraction angiography (DSA). Seven patients underwent i.v. DSA, which revealed eight carotid body tumours, and in the remaining four with jugulotympanic chemodectomas intra-arterial (i.a.) DSA was performed. We found i.v. DSA an easy and satisfactory method for the investigation of carotid body tumours but when glomus intravagale, tympanicum or jugulare is suspected an i.a. selective injection is required. (orig.) [de

  12. Digital subtraction angiography in the evaluation of chemodectomas

    Energy Technology Data Exchange (ETDEWEB)

    Vlahos, L.; Papathanasiou, M.; Gouliamos, A.; Dimakakos, P.; Papavassiliou, C.

    1988-05-01

    During the last 2 years eleven patients with surgically confirmed chemodectomas have been investigated by means of digital subtraction angiography (DSA). Seven patients underwent i.v. DSA, which revealed eight carotid body tumours, and in the remaining four with jugulotympanic chemodectomas intra-arterial (i.a.) DSA was performed. We found i.v. DSA an easy and satisfactory method for the investigation of carotid body tumours but when glomus intravagale, tympanicum or jugulare is suspected an i.a. selective injection is required.

  13. Real-time digital x-ray subtraction imaging

    International Nuclear Information System (INIS)

    Mistretta, C.A.; Kruger, R.A.; Houk, T.L.

    1982-01-01

    A method of producing visible difference images derived from an x-ray image of an anatomical subject is described. X-rays are directed through the subject, and the image is converted into television fields comprising trains of analog video signals. The analog signals are converted into digital signals, which are then integrated over a predetermined time corresponding to several television fields. Difference video signals are produced by performing a subtraction between the ongoing video signals and the corresponding integrated signals, and are converted into visible television difference images representing changes in the x-ray image

  14. Clinical application of digital subtraction angiography for arterial portography

    International Nuclear Information System (INIS)

    Ohtomo, Kuni; Furui, Shigeru; Yashiro, Naofumi; Itai, Yuji; Iio, Masahiro

    1983-01-01

    Intra-arterial digital subtraction portography(IADSP) after superior mesenteric artery injection was described. A total dose of 15 ml to 20 ml of 76% contrast medium was injected at a rate of 5 ml/sec in 14 cases (9 hepatomas, 2 metastatic liver tumors, 2 cavernous hemangiomas, 1 liver cirrhosis). In 11 cases, portal venous system was clearly demonstrated by IADSP. In 8 hepatomas tumor thrombus of portal venous system could be ruled out by IADSP and embolization therapy was carried out. IADSP was also useful for demonstrating esophageal varix and splenorenal shunt. (author)

  15. A subtractive approach to interior intrusion detection system design

    International Nuclear Information System (INIS)

    Sons, R.J.; Graham, R.H. Jr.

    1986-01-01

    This paper discusses the subtractive approach to interior intrusion detection system design which assumes that all sensors are viable candidates until they are subjected to the constraints imposed by a particular facility. The constraints are determined by a sequence of questions concerning parameters such as threat definition, facility description and operation, environment, assets to be protected, security system capabilities, and cost. As a result of the questioning, some sensors will be eliminated from the candidate list, and the ''best'' set of sensors for the facility will remain. This form of questioning could be incorporated into an expert system aiding future intrusion detection system designs

  16. Intra-arterial digital subtraction angiography of the carotid arteries

    International Nuclear Information System (INIS)

    Nakstad, P.; Bakke, S.J.; Kjartansson, O.; Nyhus, S.

    1986-01-01

    A cross-over test in intra-arterial digital subtraction angiography (IADSA) of the carotid arteries was performed in 50 patients to evaluate image quality and side-effects with iohexol and metrizoate injected at concentrations of 100 mg I/ml by hand. The image quality was excellent or good in all cases. Although the severity and the frequency of side-effects were higher with metrizoate, both contrast media were suitable for IADSA at this low concentration. No complications were seen. It was assumed that the risk with IADSA was less than that of conventional-selectivity and with small amounts of contrast media, as in this study. (orig.)

  17. [Design and development of the DSA digital subtraction workstation].

    Science.gov (United States)

    Peng, Wen-Xian; Peng, Tian-Zhou; Xia, Shun-Ren; Jin, Guang-Bo

    2008-05-01

    According to the patient examination criterion and the demands of all related departments, the DSA digital subtraction workstation has been successfully designed and is introduced in this paper by analyzing the characteristic of video source of DSA which was manufactured by GE Company and has no DICOM standard interface. The workstation includes images-capturing gateway and post-processing software. With the developed workstation, all images from this early DSA equipment are transformed into DICOM format and then are shared in different machines.

  18. Digital subtraction angiography in head and neck radiology

    International Nuclear Information System (INIS)

    Carmody, R.F.; Seeger, J.F.; Smith, R.L.; Horsley, W.W.; Miller, R.W.

    1984-01-01

    Intravenous digital subtraction angiography (IVDSA) was used to evaluate 44 patients with suspected otolaryngologic abnormalities. Sixteen had IVDSA for pulsatile tinnitus or suspected glomus tumor of the petrous bone. Nine patients were evaluated because of pulsatile neck masses, and 12 others had suspected tumors of the neck, face, and paranasal sinuses. Seven had IVDSA following head and neck trauma. The technique of examination is described. The current indications of IVDSA in head and neck radiology are discussed. It is concluded that IVDSA is a suitable substitute for conventional angiography for many otolaryngologic conditions and, because of its safety, can be used more liberally. (orig.)

  19. Digital subtraction angiography in head and neck radiology

    Energy Technology Data Exchange (ETDEWEB)

    Carmody, R F; Seeger, J F; Smith, R L; Horsley, W W; Miller, R W

    1984-07-01

    Intravenous digital subtraction angiography (IVDSA) was used to evaluate 44 patients with suspected otolaryngologic abnormalities. Sixteen had IVDSA for pulsatile tinnitus or suspected glomus tumor of the petrous bone. Nine patients were evaluated because of pulsatile neck masses, and 12 others had suspected tumors of the neck, face, and paranasal sinuses. Seven had IVDSA following head and neck trauma. The technique of examination is described. The current indications of IVDSA in head and neck radiology are discussed. It is concluded that IVDSA is a suitable substitute for conventional angiography for many otolaryngologic conditions and, because of its safety, can be used more liberally.

  20. Manual for the Jet Event and Background Simulation Library

    Energy Technology Data Exchange (ETDEWEB)

    Heinz, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Soltz, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Angerami, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-11

    Jets are the collimated streams of particles resulting from hard scattering in the initial state of high-energy collisions. In heavy-ion collisions, jets interact with the quark-gluon plasma (QGP) before freezeout, providing a probe into the internal structure and properties of the QGP. In order to study jets, background must be subtracted from the measured event, potentially introducing a bias. We aim to understand and quantify this subtraction bias. PYTHIA, a library to simulate pure jet events, is used to simulate a model for a signature with one pure jet (a photon) and one quenched jet, where all quenched particle momenta are reduced by a user-de ned constant fraction. Background for the event is simulated using multiplicity values generated by the TRENTO initial state model of heavy-ion collisions fed into a thermal model consisting of a 3-dimensional Boltzmann distribution for particle types and momenta. Data from the simulated events is used to train a statistical model, which computes a posterior distribution of the quench factor for a data set. The model was tested rst on pure jet events and then on full events including the background. This model will allow for a quantitative determination of biases induced by various methods of background subtraction.

  1. Background suppression of infrared small target image based on inter-frame registration

    Science.gov (United States)

    Ye, Xiubo; Xue, Bindang

    2018-04-01

    We propose a multi-frame background suppression method for remote infrared small target detection. Inter-frame information is necessary when the heavy background clutters make it difficult to distinguish real targets and false alarms. A registration procedure based on points matching in image patches is used to compensate the local deformation of background. Then the target can be separated by background subtraction. Experiments show our method serves as an effective preliminary of target detection.

  2. BGSUB and BGFIX: FORTRAN programs to correct Ge(Li) gamma-ray spectra for photopeaks from radionuclides in background

    International Nuclear Information System (INIS)

    Cutshall, N.H.; Larsen, I.L.

    1980-03-01

    Two FORTRAN programs which provide correction and error analysis for background photopeak contributions to low-level gamma-ray spectra are discussed. A peak-by-peak background subtraction approach is used instead of channel-by-channel correction. The accuracy of corrected results near background levels is substantially improved over uncorrected values

  3. Evaluation of left ventricular function using digital subtraction ventriculography

    International Nuclear Information System (INIS)

    Yiannikas, J.; Detrano, R.

    1986-01-01

    Digital subtraction ventriculography following injections of contrast via peripheral veins provides excellent images to assess left ventricular function. The images are essentially identical to those following DCV, but allow more uniform mixing of contrast in the left ventricular chamber. Furthermore, few, if any, cardiac arrhythmias occur, hence obviating difficulties that arise from DCV. The spatial resolution of the method is such that regional wall motion assessment of ventricular function is more accurate than that of other noninvasive imaging methods. The use of video-densitometry allows accurate assessment of left ventricular function even when the left ventricular cavity is nonsymmetrically deformed and aneurysmal. In the setting of the cardiac catheterization laboratory, digital ventriculography may provide a safer means of assessing left ventricular function when critical coronary or myocardial disease is present and allows multiple assessments of ventricular function during the same study. Although excellent correlations with standard ventriculography have been noted by all workers, significant discrepancies still exist in individual patients, particularly in the calculations of end diastolic volumes. In the authors experience and in those of most workers, the largest discrepancies existed in patients in whom suboptimal studies are included for analysis. The most frequent reason for the occasional suboptimal study as with all digital subtraction work is the misregistration that results from motion

  4. Digital subtraction angiography in 105 living renal transplant donors

    International Nuclear Information System (INIS)

    Suh, Ho Jong; Oh, Kyung Seung; Kim, So Sun; Huh, Jin Do; Kim, Ho Joon; Chun, Byung Hee; Joh, Young Duck

    1989-01-01

    In order to analyze the number and length of the renal arteries and to evaluate abnormalities of the renal parenchyma and vessel, digital subtraction angiogram images of 105 potential renal donors (45 men and 60 women aged 17-66 years) were studied retrospectively. For the entire series, 31 donors had multiple renal arteries on one side (15 on the left, 11 on the right) and 5 donors on the both sides. 89 donors were family related either parents or siblings of recipients. The estimation of the length of the renal artery was based on the mean height of the second lumbar vertebral body (L2). The right renal artery is significant longer than on the left and measured more than the height of L2 vertebral body in 84 cases on the right and 60 cases on the left. Twenty two donors underwent right nephrectomy due to presence of multiple renal arteries on the left (N=14), proximal bifurcation of left main renal artery (N=3), and young females in reproductive age (N=5). Unexpected abnormalities found with angiogram were seen in 7 cases and they include renal artery stenosis (N=2), renal cysts (N=4) and focal infarction (N=1). In cases of the renal cysts and focal infarction, there were no serious complications related to the abnormalities. It is conclude that intra-arterial digital subtraction angiography is safe and efficient method to image renal anatomy of the potential renal donors

  5. Intraarterial digital subtraction angiography applied to diagnosis of hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Nishizawa, Sadahiko; Sano, Akira; Imanaka, Kazufumi; Sasai, Keisuke; Nagae, Toshiyuki; Mizutani, Masaru; Hatabu, Hiroto; Sadatou, Norihiro; Kuroda, Yasumasa

    1985-12-01

    This paper deals with diagnostic values of intraarterial digital subtraction angiography (IADSA) for evaluating hepatocellular carcinoma. The present series consists of 44 patients with hepatocellular carcinoma, who underwent IADSA combined with conventional hepatic angiography 67 times in total. The evaluated vessels by IADSA included 70 hepatic arteries and 36 portal veins. Comparative studies on the image quality of IADSA with conventional angiography were made in referring to the tumor stain for arteriograms and resolution of intrahepatic portal branches for portograms. Diagnostic superiority including equality of DSA image to conventional was noted in arteriograms: 72.7 % in the right lobe and 86 % in the left. Most deteriorated DSA images were caused by misregistration artifacts. IADSA portography revealed basically diagnostic values to demonstrate lobar, segmental or more peripheral branches in about 95 % of cases studied. DSA, characterized by high contrast resolution and real-time subtraction, offered important and effective informations for interventional angiography as well as resectability of the tumors, requiring less contrast medium.

  6. Iodine filter imaging system for subtraction angiography using synchrotron radiation

    Science.gov (United States)

    Umetani, K.; Ueda, K.; Takeda, T.; Itai, Y.; Akisada, M.; Nakajima, T.

    1993-11-01

    A new type of real-time imaging system was developed for transvenous coronary angiography. A combination of an iodine filter and a single energy broad-bandwidth X-ray produces two-energy images for the iodine K-edge subtraction technique. X-ray images are sequentially converted to visible images by an X-ray image intensifier. By synchronizing the timing of the movement of the iodine filter into and out of the X-ray beam, two output images of the image intensifier are focused side by side on the photoconductive layer of a camera tube by an oscillating mirror. Both images are read out by electron beam scanning of a 1050-scanning-line video camera within a camera frame time of 66.7 ms. One hundred ninety two pairs of iodine-filtered and non-iodine-filtered images are stored in the frame memory at a rate of 15 pairs/s. In vivo subtracted images of coronary arteries in dogs were obtained in the form of motion pictures.

  7. Temporal digital subtraction radiography with a personal computer digital workstation

    International Nuclear Information System (INIS)

    Kircos, L.; Holt, W.; Khademi, J.

    1990-01-01

    Technique have been developed and implemented on a personal computer (PC)-based digital workstation to accomplish temporal digital subtraction radiography (TDSR). TDSR is useful in recording radiologic change over time. Thus, this technique is useful not only for monitoring chronic disease processes but also for monitoring the temporal course of interventional therapies. A PC-based digital workstation was developed on a PC386 platform with add-in hardware and software. Image acquisition, storage, and processing was accomplished using 512 x 512 x 8- or 12-bit frame grabber. Software and hardware were developed to accomplish image orientation, registration, gray scale compensation, subtraction, and enhancement. Temporal radiographs of the jaws were made in a fixed and reproducible orientation between the x-ray source and image receptor enabling TDSR. Temporal changes secondary to chronic periodontal disease, osseointegration of endosseous implants, and wound healing were demonstrated. Use of TDSR for chest imaging was also demonstrated with identification of small, subtle focal masses that were not apparent with routine viewing. The large amount of radiologic information in images of the jaws and chest may obfuscate subtle changes that TDSR seems to identify. TDSR appears to be useful as a tool to record temporal and subtle changes in radiologic images

  8. Subtractive fabrication of ferroelectric thin films with precisely controlled thickness

    Science.gov (United States)

    Ievlev, Anton V.; Chyasnavichyus, Marius; Leonard, Donovan N.; Agar, Joshua C.; Velarde, Gabriel A.; Martin, Lane W.; Kalinin, Sergei V.; Maksymovych, Petro; Ovchinnikova, Olga S.

    2018-04-01

    The ability to control thin-film growth has led to advances in our understanding of fundamental physics as well as to the emergence of novel technologies. However, common thin-film growth techniques introduce a number of limitations related to the concentration of defects on film interfaces and surfaces that limit the scope of systems that can be produced and studied experimentally. Here, we developed an ion-beam based subtractive fabrication process that enables creation and modification of thin films with pre-defined thicknesses. To accomplish this we transformed a multimodal imaging platform that combines time-of-flight secondary ion mass spectrometry with atomic force microscopy to a unique fabrication tool that allows for precise sputtering of the nanometer-thin layers of material. To demonstrate fabrication of thin-films with in situ feedback and control on film thickness and functionality we systematically studied thickness dependence of ferroelectric switching of lead-zirconate-titanate, within a single epitaxial film. Our results demonstrate that through a subtractive film fabrication process we can control the piezoelectric response as a function of film thickness as well as improve on the overall piezoelectric response versus an untreated film.

  9. Motion compensation in digital subtraction angiography using graphics hardware.

    Science.gov (United States)

    Deuerling-Zheng, Yu; Lell, Michael; Galant, Adam; Hornegger, Joachim

    2006-07-01

    An inherent disadvantage of digital subtraction angiography (DSA) is its sensitivity to patient motion which causes artifacts in the subtraction images. These artifacts could often reduce the diagnostic value of this technique. Automated, fast and accurate motion compensation is therefore required. To cope with this requirement, we first examine a method explicitly designed to detect local motions in DSA. Then, we implement a motion compensation algorithm by means of block matching on modern graphics hardware. Both methods search for maximal local similarity by evaluating a histogram-based measure. In this context, we are the first who have mapped an optimizing search strategy on graphics hardware while paralleling block matching. Moreover, we provide an innovative method for creating histograms on graphics hardware with vertex texturing and frame buffer blending. It turns out that both methods can effectively correct the artifacts in most case, as the hardware implementation of block matching performs much faster: the displacements of two 1024 x 1024 images can be calculated at 3 frames/s with integer precision or 2 frames/s with sub-pixel precision. Preliminary clinical evaluation indicates that the computation with integer precision could already be sufficient.

  10. Counting the mismatches - lung ventilation/perfusion subtraction index

    International Nuclear Information System (INIS)

    Anderson, T.C.; Evans, S.G.; Larcos, G.; Farlow, D.C.

    1998-01-01

    Full text: There is potential for interobserver variability in interpretation of ventilation/perfusion (V/Q) scans. Objective quantification of V/Q mismatch could be useful. Thus, the aim of this study is to determine the validity of image subtraction in a group of 27 patients (11 men, 8 women; mean age 59.4 years [range 21-81 years])investigated by V/Q scans for suspected pulmonary emboli. A standard 6 view V/Q scan was obtained with two cobalt markers used on the anterior and posterior surfaces for image alignment. Ventilation images were normalised to the perfusion using an area of normal ventilation and perfusion. With the use of automated, and if required, manual alignment, perfusion images were subtracted from ventilation, with a median filter applied. A summed index of mismatch for each lung scan was calculated from the difference. This index was then retrospectively compared to the result reported by one of four experienced physicians. Two patients with chronic obstructive airways disease were excluded from analysis. We conclude that high probability V/Q scans can be differentiated from low probability studies using this index; further prospective investigation in a larger cohort is warranted

  11. [sup 99m]Tc-RBC subtraction scintigraphy; Assessmet of bleeding site and rate

    Energy Technology Data Exchange (ETDEWEB)

    Inagaki, Syoichi; Tonami, Syuichi; Yasui, Masakazu; Kuranishi, Makoto; Sugishita, Kouki; Nakamura, Mamoru (Toyama Medical and Pharmaceutical Univ. (Japan). Hospital)

    1994-03-01

    Sequential abdominal scintigrams with [sup 99m]Tc-labelled red blood cells (RBC) were subtracted for observing a site of gastrointestinal bleeding and calculating the bleeding rate. This method is technically very easy and can detect the site of bleeding with the minimum rate, as low as 0.2 ml/min., in a phantom experiment. In 23 cases with final diagnosis of gastrointestinal bleeding, conventional non-subtraction scintigraphy detected only 30% (7/23), but subtraction scintigraphy detected 61% (14/23). It was concluded that subtraction scintigraphy had higher sensitivity than conventional scintigraphy for early diagnosing bleeding. A combination of non-subtraction and subtraction scintigraphy is recommended to detect a site of gastrointestinal bleeding in a clinical setting. (author).

  12. Improved Savitzky-Golay-method-based fluorescence subtraction algorithm for rapid recovery of Raman spectra.

    Science.gov (United States)

    Chen, Kun; Zhang, Hongyuan; Wei, Haoyun; Li, Yan

    2014-08-20

    In this paper, we propose an improved subtraction algorithm for rapid recovery of Raman spectra that can substantially reduce the computation time. This algorithm is based on an improved Savitzky-Golay (SG) iterative smoothing method, which involves two key novel approaches: (a) the use of the Gauss-Seidel method and (b) the introduction of a relaxation factor into the iterative procedure. By applying a novel successive relaxation (SG-SR) iterative method to the relaxation factor, additional improvement in the convergence speed over the standard Savitzky-Golay procedure is realized. The proposed improved algorithm (the RIA-SG-SR algorithm), which uses SG-SR-based iteration instead of Savitzky-Golay iteration, has been optimized and validated with a mathematically simulated Raman spectrum, as well as experimentally measured Raman spectra from non-biological and biological samples. The method results in a significant reduction in computing cost while yielding consistent rejection of fluorescence and noise for spectra with low signal-to-fluorescence ratios and varied baselines. In the simulation, RIA-SG-SR achieved 1 order of magnitude improvement in iteration number and 2 orders of magnitude improvement in computation time compared with the range-independent background-subtraction algorithm (RIA). Furthermore the computation time of the experimentally measured raw Raman spectrum processing from skin tissue decreased from 6.72 to 0.094 s. In general, the processing of the SG-SR method can be conducted within dozens of milliseconds, which can provide a real-time procedure in practical situations.

  13. A feasibility study of projection-based energy weighting based on a photon-counting detector in contrast-enhanced digital subtraction mammography: a simulation study

    International Nuclear Information System (INIS)

    Choi, Sunghoon; Lee, Seungwan; Choi, Yuna; Kim, Heejoung

    2014-01-01

    Contrast media, such as iodine and gadolinium, are generally used in digital subtraction mammography to enhance the contrast between target and background materials. In digital subtraction mammography, where one image (with contrast medium) is subtracted from another (anatomical background) to facilitate visualization of the tumor structure, tumors can be more easily distinguished after the injection of a contrast medium. In order to have more an effective method to increase the contrast-to-noise ratio (CNR), we applied a projection-based energy-weighting method. The purpose of this study is to demonstrate the feasibility of using the projection-based energy-weighting method in digital subtraction mammography. Unlike some other previous studies, we applied the projection-based energy-weighting method to more practical mammography conditions by using the Monte Carlo method to simulate four different iodine solutions embedded in a breast phantom comprised of 50% adipose and 50% glandular tissues. We also considered an optimal tube voltage and anode/filter combination in digital iodine contrast media mammography in order to maximize the figure-of-merit (FOM). The simulated source energy was from 20 to 45 keV to prevent electronic noise and include the k-edge energy of iodine (33.2 keV). The results showed that the projection-based energy-weighting improved the CNR by factors of 1.05 - 1.86 compared to the conventionally integrated images. Consequently, the CNR of digital subtraction mammography images can be improved by using projection-based energy-weighting with photon-counting detectors.

  14. A feasibility study of projection-based energy weighting based on a photon-counting detector in contrast-enhanced digital subtraction mammography: a simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sunghoon; Lee, Seungwan; Choi, Yuna; Kim, Heejoung [Yonsei University, Wonju (Korea, Republic of)

    2014-06-15

    Contrast media, such as iodine and gadolinium, are generally used in digital subtraction mammography to enhance the contrast between target and background materials. In digital subtraction mammography, where one image (with contrast medium) is subtracted from another (anatomical background) to facilitate visualization of the tumor structure, tumors can be more easily distinguished after the injection of a contrast medium. In order to have more an effective method to increase the contrast-to-noise ratio (CNR), we applied a projection-based energy-weighting method. The purpose of this study is to demonstrate the feasibility of using the projection-based energy-weighting method in digital subtraction mammography. Unlike some other previous studies, we applied the projection-based energy-weighting method to more practical mammography conditions by using the Monte Carlo method to simulate four different iodine solutions embedded in a breast phantom comprised of 50% adipose and 50% glandular tissues. We also considered an optimal tube voltage and anode/filter combination in digital iodine contrast media mammography in order to maximize the figure-of-merit (FOM). The simulated source energy was from 20 to 45 keV to prevent electronic noise and include the k-edge energy of iodine (33.2 keV). The results showed that the projection-based energy-weighting improved the CNR by factors of 1.05 - 1.86 compared to the conventionally integrated images. Consequently, the CNR of digital subtraction mammography images can be improved by using projection-based energy-weighting with photon-counting detectors.

  15. Digital subtraction CT angiography for the detection of posterior inferior cerebellar artery aneurysms: comparison with digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Guo Zhong; Luo, Song; Zhou, Chang Sheng; Zhang, Long Jiang; Lu, Guang Ming [Jinling Hospital, Medical School of Nanjing University, Department of Medical Imaging, Nanjing, Jiangsu (China)

    2017-09-15

    To evaluate the diagnostic accuracy of digital subtraction CT angiography (DS-CTA) in detecting posterior inferior cerebellar artery (PICA) aneurysms with digital subtraction angiography (DSA) as reference standard. A total of 115 patients, including 56 patients diagnosed with PICA aneurysms by CTA or DSA and 59 non-PICA-aneurysm patients were included in this retrospective study. All patients underwent DS-CTA and DSA. The site of PICA aneurysms and the pattern of haemorrhage were analysed. Sensitivity and specificity of DS-CTA without and with combining haemorrhage pattern in diagnosing PICA aneurysms were evaluated on a per patient and per aneurysm basis with DSA. Of 115 patients, 56 patients (48.7%) had 61 PICA aneurysms (size range, 1.1-13.5 mm; mean size, 4.9 ± 2.8 mm) on DSA. The sensitivity and specificity in depicting PICA aneurysms were 89.3% and 96.6% on a per patient basis and 90.2% and 93.4% on a per aneurysm basis, while the corresponding values were 94.6% and 96.6% on a per patient basis and 95.1% and 93.4% on a per aneurysm basis when combining with haemorrhage site. DS-CTA has a high sensitivity and specificity in detecting PICA aneurysms compared with DSA. It may be helpful for clinical diagnosis of PICA aneurysms to combine with haemorrhage sites. (orig.)

  16. Combined nuclear and digital subtraction contrast arthrography in painful knee prosthesis

    International Nuclear Information System (INIS)

    Namasivayam, J.; Forrester, A.; Poon, F.W.; Cuthbert, G.F.; McKillop, J.H.; Bryan, A.S.

    1992-01-01

    The evaluation of a painful knee prosthesis remains a difficult problem for both orthopaedic surgeons and radiologists. We have compared digital subtraction arthrography with nuclear-arthrography in 7 patients with a painful knee prosthesis. Three patients showed a loose tibial component, demonstrated by both digital subtraction and nuclear arthrography. All 3 underwent revision of their prosthesis. One patient had an equivocal digital subtraction arthrogram and negative nuclear arthrogram, while both studies were negative in the 3 remaining patients. Nuclear arthrography is a simple procedure and can provide useful additional information when combined with digital subtraction arthrography. (orig.)

  17. Arthrography of painful hips following arthroplasty: Digital versus plain film subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Walker, C W; FitzRandolph, R L; Dalrymple, G V [Arkansas Univ. for Medical Sciences, Little Rock, AR (USA). Dept. of Radiology John McClellan Memorial Veterans Hospital, Little Rock, AR (USA); Collins, D N [Arkansas Univ. for Medical Sciences, Little Rock, AR (USA). Dept. of Orthopedics John McClellan Memorial Veterans Hospital, Little Rock, AR (USA)

    1991-08-01

    Digital and manual subtraction images obtained during the arthrographic evaluation of 78 painful hip prostheses were reviewed retrospectively. Revision arthroplasty was performed in 53 of these cases, and the arthrographic and surgical findings were correlated. The digital and manual subtraction images were evaluated without knowledge of the surgical results using established criteria for component loosening. The difference between detection of femoral component loosening on digital as opposed to manual subtraction images was statistically significant (P < 0.05). This study demonstrates that digital subtraction improves the evaluation of femoral component loosening in painful hip prostheses. (orig./GDG).

  18. The Role of Bone Subtraction Computed Tomographic Angiography in Determining Intracranial Aneurysms in Non-Traumatic Subarachnoid Hemorrhage

    Science.gov (United States)

    Kayhan, Aysegul; Koc, Osman; Keskin, Suat; Keskin, Fatih

    2014-01-01

    Background: The presence of blood in the subarachnoid space is an acute pathology with a serious risk of death and complications. The most common etiology (approximately 80%) is intracranial aneurysm. Objectives: The aim of this study was to assess the role of bone subtracted computed tomographic angiography (BSCTA), a novel and noninvasive method for determining and characterizing intracranial aneurysms. Patients and Methods: Sixty consecutive patients with clinically suspected non-traumatic subarachnoid hemorrhage (SAH) were considered to enter the study. The subtraction quality was inadequate in ten patients; thus, they were excluded, leaving 50 patients (84.4%) in the study. Bone subtracted and non-subtracted 3D images were obtained from the BSCTA raw data sets. All images obtained by digital subtraction angiography (DSA), BSCTA, and computed tomographic angiography (CTA) were evaluated for the presence or absence of an aneurysm and the location, minimal sac diameter, and neck size ratio of the aneurysm. DSA was considered as the gold standard during the evaluation of the data. Results: Of the 50 patients who participated in this study, 11 had no aneurysms as determined by both CTA and DSA. Examination of the remaining 39 patients revealed the presence of 51 aneurysms. While 3D-CTA could not detect six aneurysms that were located in the base of the skull, 3D-BSCTA easily detected them. Moreover, five aneurysms were only partially detected by 3D-CTA. According to this data, the sensitivity of 3D-BSCTA and 3D-CTA was calculated as 98% and 86.3%, respectively; the specificity was calculated as 100% and 90.9%, respectively, per aneurysm; and the sensitivity of 100% for 3D-BSCTA and 98% for 3D-CTA was achieved by using combined images with multi-planar reconstruction (MPR) and maximum intensity projection (MIP). BSCTA detected and characterized the aneurysms as well as DSA, and BSCTA and DSA gave concordant results in detecting aneurysms. Conclusions: BSCTA is

  19. Averaged subtracted polarization imaging for endoscopic diagnostics of surface microstructures on translucent mucosae

    Science.gov (United States)

    Kanamori, Katsuhiro

    2016-07-01

    An endoscopic image processing technique for enhancing the appearance of microstructures on translucent mucosae is described. This technique employs two pairs of co- and cross-polarization images under two different linearly polarized lights, from which the averaged subtracted polarization image (AVSPI) is calculated. Experiments were then conducted using an acrylic phantom and excised porcine stomach tissue using a manual experimental setup with ring-type lighting, two rotating polarizers, and a color camera; better results were achieved with the proposed method than with conventional color intensity image processing. An objective evaluation method that uses texture analysis was developed and used to evaluate the enhanced microstructure images. This paper introduces two types of online, rigid-type, polarimetric endoscopic implementations using a polarized ring-shaped LED and a polarimetric camera. The first type uses a beam-splitter-type color polarimetric camera, and the second uses a single-chip monochrome polarimetric camera. Microstructures on the mucosa surface were enhanced robustly with these online endoscopes regardless of the difference in the extinction ratio of each device. These results show that polarimetric endoscopy using AVSPI is both effective and practical for hardware implementation.

  20. Robustness Beamforming Algorithms

    Directory of Open Access Journals (Sweden)

    Sajad Dehghani

    2014-04-01

    Full Text Available Adaptive beamforming methods are known to degrade in the presence of steering vector and covariance matrix uncertinity. In this paper, a new approach is presented to robust adaptive minimum variance distortionless response beamforming make robust against both uncertainties in steering vector and covariance matrix. This method minimize a optimization problem that contains a quadratic objective function and a quadratic constraint. The optimization problem is nonconvex but is converted to a convex optimization problem in this paper. It is solved by the interior-point method and optimum weight vector to robust beamforming is achieved.

  1. Robustness Metrics: Consolidating the multiple approaches to quantify Robustness

    DEFF Research Database (Denmark)

    Göhler, Simon Moritz; Eifler, Tobias; Howard, Thomas J.

    2016-01-01

    robustness metrics; 3) Functional expectancy and dispersion robustness metrics; and 4) Probability of conformance robustness metrics. The goal was to give a comprehensive overview of robustness metrics and guidance to scholars and practitioners to understand the different types of robustness metrics...

  2. Robustness of structures

    DEFF Research Database (Denmark)

    Vrouwenvelder, T.; Sørensen, John Dalsgaard

    2009-01-01

    After the collapse of the World Trade Centre towers in 2001 and a number of collapses of structural systems in the beginning of the century, robustness of structural systems has gained renewed interest. Despite many significant theoretical, methodical and technological advances, structural...... of robustness for structural design such requirements are not substantiated in more detail, nor have the engineering profession been able to agree on an interpretation of robustness which facilitates for its uantification. A European COST action TU 601 on ‘Robustness of structures' has started in 2007...... by a group of members of the CSS. This paper describes the ongoing work in this action, with emphasis on the development of a theoretical and risk based quantification and optimization procedure on the one side and a practical pre-normative guideline on the other....

  3. Robust Approaches to Forecasting

    OpenAIRE

    Jennifer Castle; David Hendry; Michael P. Clements

    2014-01-01

    We investigate alternative robust approaches to forecasting, using a new class of robust devices, contrasted with equilibrium correction models. Their forecasting properties are derived facing a range of likely empirical problems at the forecast origin, including measurement errors, implulses, omitted variables, unanticipated location shifts and incorrectly included variables that experience a shift. We derive the resulting forecast biases and error variances, and indicate when the methods ar...

  4. Robustness - theoretical framework

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Rizzuto, Enrico; Faber, Michael H.

    2010-01-01

    More frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure combined with increased requirements to efficiency in design and execution followed by increased risk of human errors has made the need of requirements to robustness of new struct...... of this fact sheet is to describe a theoretical and risk based framework to form the basis for quantification of robustness and for pre-normative guidelines....

  5. Evaluation and quality control of digital subtraction angiography systems

    International Nuclear Information System (INIS)

    Louisot, P.

    1986-04-01

    After reviewing the development of systems used in angiography, we rewind the medical interest and describe the steps of an angiographic examination. The following chapter is dedicated to the techniques used for the digitalization of video images. The components of the system involved in the image acquisition are thoroughly investigated in chapter 4. Then, we analyse the capabilities of the machines available in France in 1985. Chapter 6 is devoted to the criteria of quality in digital imaging. In order to assign qualitative values to the above criteria, we design a control procedure which is described in chapter 7. The procedure thus allows the estimate of the physical performances of angiographic digital subtraction systems [fr

  6. Digital subtraction angiography with an Isocon camera system: clinical applications

    International Nuclear Information System (INIS)

    Barbaric, Z.L.; Gomes, A.S.; Deckard, M.E.; Nelson, R.S.; Moler, C.L.

    1984-01-01

    A new imaging system for digital subtraction angiography (DSA) was evaluated in 30 clinical studies. The image receptor is a 25 X 25 cm, 12 par gadolinium oxysulfate rare-earth screen whose light output is focused to a low-light-level Isocon camera. The video signal is digitized and processed by an image-array processor containing 31 512 X 512 memories 8 bits deep. In most patients, intraarterial DSA studies were done in conjunction with conventional arteriography. In these arterial studies, images adequate to make a specific diagnosis were obtained using half the radiation dose and half the amount of contrast material needed for conventional angiography. In eight intravenous studies performed either to identify renal artery stenosis or for evaluation of congenital heart anomalies, the images were diagnostic but objectionably noisy

  7. Real-time digital x-ray subtraction imaging

    International Nuclear Information System (INIS)

    Mistretta, C.A.

    1982-01-01

    The invention provides a method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through the anatomical subject for producing an image, converting the image into television fields comprising trains of on-going video signals, digitally storing and integrating the on-going video signals over a time interval corresponding to several successive television fields and thereby producing stored and integrated video signals, recovering the video signals from storage and producing integrated video signals, producing video difference signals by performing a subtraction between the integrated video signals and the on-going video signals outside the time interval, and converting the difference signals into visible television difference images representing on-going changes in the X-ray image

  8. Method and apparatus for performing digital intravenous subtraction angiography

    International Nuclear Information System (INIS)

    Stein, J.A.

    1986-01-01

    This invention relates to digital intravenous subtraction angiography (DISA), and more particularly concerns novel apparatus and techniques for providing high resolution angiograms with equipment that coacts with existing standard medical X-ray equipment. A typical medical X-ray generator provides low mA, continuous X-ray exposures illuminating a standard image intensifier producing an image scanned by a conventional television camera to produce a video signal. An analog-to-digital converter digitizes the signal, and adding means adds the digital frame signals together in real time to provide an intermediate digital signal representing the addition of 5 to 20 frames. Digital storage means store the intermediate image signals. Preferably there are two system memories with means for summing a subsequent intermediate image in the second memory while a previously-formed intermediate image is being transferred to disk storage

  9. Real-time digital X-ray subtraction imaging

    International Nuclear Information System (INIS)

    Mistretta, C.A.; Kruger, R.A.; Houk, T.L.

    1979-01-01

    A diagnostic anatomical X-ray apparatus comprising a converter and a television camera for converting an X-ray image of a subject into a series of television fields of video signals is described in detail. A digital memory system stores and integrates the video signals over a time interval corresponding to a plurality of successive television fields. The integrated video signals are recovered from storage and fed to a digital or analogue subtractor, the resulting output being displayed on a television monitor. Thus the display represents on-going changes in the anatomical X-ray image. In a modification, successive groups of fields are stored and integrated in three memories, cyclically, and subtractions are performed between successive pieces of integrated signals to provide a display of successive alterations in the X-ray image. For investigations of the heart, the integrating interval should be of the order of one cardiac cycle. (author)

  10. Double-nuclide subtraction scintiscanning of the pancreas

    International Nuclear Information System (INIS)

    Streithoff, E.C.

    1978-01-01

    The paper intends to find out if there is a correlation between clinical pancreas diagnoses and diagnoses by subtraction scintiscanning; furthermore, the findings of scintiscanning are compared with those of radiological and sonographic methods. In order to get a picture of the efficiency of the methods applied, not only their accuracy is determined but also their validity sum and validity product. The best results are achieved here with angiography, ERCP, and sonography. In the case of pancreatic scintiscanning, an optimal result well above the international standard is only obtained for sensitivity. On the basis of these results, the indications for an optimal and useful application of pancreatic scintiscanning are determined. (orig./AJ) [de

  11. Multinuclide digital subtraction imaging in symptomatic prostnetic joints

    International Nuclear Information System (INIS)

    Chafetz, N.; Hattner, R.S.; Ruarke, W.C.; Helms, C.A.; Genant, H.K.; Murray, W.R.

    1985-01-01

    One hundred eleven patients with symptomatic prosthetic joints (86 hips, 23 knees, and two shoulders) were evaluated for prosthetic loosening and infection by combined technetium-99m-MDP/gallium-67 digital subtraction imaging. Clinical correlation was based on the assessment of loosening and bacterial cultures obtained at the time of surgery in 54 patients, joint aspiration cultures obtained in 37 patients, and long-term clinical follow-up for greater than 1.5 years in an additional 15 patients. Results revealed an 80-90% predictive value of a positive test for loosening, and a 95% predictive value of a negative test for infection. However, because of the low sensitivities and specificities observed, this approach to the evaluation of symptomatic prosthetic joints does not seem cost effective

  12. Thallium-technetium-subtraction scintigraphy in secondary hyperparathyroidism

    International Nuclear Information System (INIS)

    Adalet, I.; Hawkins, T.; Clark, F.; Wilkinson, R.

    1994-01-01

    Between 1983 and 1992 thallium-technetium subtraction scintigraphy (TTS) was performed on 74 patients with clinical and biochemical evidence of hyperparathyroidism. Twenty-five of the 53 investigations since 1988 were conducted on patients with renal failure with a suspicion of secondary hyperparathyroidism. In a retrospective study we have evaluated radioisotope scintigraphy for patients with adenoma and for renal failure patients with possible parathyroid hyperplasia. Thirty of 74 patients underwent neck exploration. Scintigraphy detected 17 of 24 parathyroid adenomas (sensitivity 71%). In contrast, in six renal patients who came to operation, scintigraphy localised only 5 of 20 hyperplastic parathyroid glands (sensitivity 25%) and in one renal patient we localised a parathyroid adenoma. A review of the literature shows low detection rates for hyperplasia by TTS to be a common observation. Based on these findings a rational approach is offered for parathyroid localisation in renal patients prior to neck exploration. (orig.)

  13. Qualitative Robustness in Estimation

    Directory of Open Access Journals (Sweden)

    Mohammed Nasser

    2012-07-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Times New Roman","serif";} Qualitative robustness, influence function, and breakdown point are three main concepts to judge an estimator from the viewpoint of robust estimation. It is important as well as interesting to study relation among them. This article attempts to present the concept of qualitative robustness as forwarded by first proponents and its later development. It illustrates intricacies of qualitative robustness and its relation with consistency, and also tries to remove commonly believed misunderstandings about relation between influence function and qualitative robustness citing some examples from literature and providing a new counter-example. At the end it places a useful finite and a simulated version of   qualitative robustness index (QRI. In order to assess the performance of the proposed measures, we have compared fifteen estimators of correlation coefficient using simulated as well as real data sets.

  14. Evaluation of left ventricular function by digital subtraction angiography

    International Nuclear Information System (INIS)

    Kuribayashi, Sachio; Ootaki, Makoto; Matsuyama, Seiya; Kanemoto, Nariaki; Furuya, Hideo

    1985-01-01

    Effects of contrast medium doses on left ventriculographic images using intravenous digital subtraction angiography (IVDSA-LVG) were assessed. The validity of IVDSA-LVG in evaluating ejection fraction (FF) and left ventricular regional wall motion was determined by comparison with conventional left ventriculography using direct injection (direct LVG). The advantages of left ventriculography using intraarterial subtraction angiography (IADSA-LVG) performed by injecting small doses of contrast media directly into the left ventricle were stressed. 1. To assess the effects of doses of contrast media on IVDSA-LVG, 10, 20, and 30 ml Urografin-76 were injected into the superior vena cava in 16 patients, and the resulting images were compared in each patient. With only 10 ml contrast medium, left ventricular opacification was fairly good, and regional wall motion was evaluated in many cases, but 30 ml were needed to calculate ventricular volume and EF. 2. To determine the validity of IVDSA-LVG in evaluating EF and regional wall motion, we compared IVDSA-LVG using 30 ml of contrast medium with direct LVG in 18 patients. There was a good correlation between the two methods in determining EF (r = 0.877), and 90 % of the interpretations of regional wall motion were in agreement by the two methods. IVDSA-LVG was useful and accurate in evaluating EF and regional wall motion of the left ventricle. 3. IADSA-LVG was performed for five patients, and good quality images were obtained in many cases, even with relatively small doses (10 ml) of contrast media. These results suggested that this method may be used in cases with impaired LV function, to avoid hemodynamic derangement induced by conventional direct LVG using large doses of contrast medium. (author)

  15. Motion induced second order temperature and y-type anisotropies after the subtraction of linear dipole in the CMB maps

    International Nuclear Information System (INIS)

    Sunyaev, Rashid A.; Khatri, Rishi

    2013-01-01

    y-type spectral distortions of the cosmic microwave background allow us to detect clusters and groups of galaxies, filaments of hot gas and the non-uniformities in the warm hot intergalactic medium. Several CMB experiments (on small areas of sky) and theoretical groups (for full sky) have recently published y-type distortion maps. We propose to search for two artificial hot spots in such y-type maps resulting from the incomplete subtraction of the effect of the motion induced dipole on the cosmic microwave background sky. This dipole introduces, at second order, additional temperature and y-distortion anisotropy on the sky of amplitude few μK which could potentially be measured by Planck HFI and Pixie experiments and can be used as a source of cross channel calibration by CMB experiments. This y-type distortion is present in every pixel and is not the result of averaging the whole sky. This distortion, calculated exactly from the known linear dipole, can be subtracted from the final y-type maps, if desired

  16. A subtraction scheme for computing QCD jet cross sections at NNLO. Integrating the iterated singly-unresolved subtraction terms

    Energy Technology Data Exchange (ETDEWEB)

    Bolzoni, Paolo [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Somogyi, Gabor [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Trocsanyi, Zoltan [Debrecen Univ. (Hungary); Hungarian Academy of Sciences, Debrecen (Hungary). Inst. of Nuclear Research

    2010-11-15

    We perform the integration of all iterated singly-unresolved subtraction terms over the two-particle factorized phase space. We also sum over the unresolved parton flavours. The final result can be written as a convolution (in colour space) of the Born cross section and an insertion operator. We spell out the insertion operator in terms of 24 basic integrals that are defined explicitly. We compute the coefficients of the Laurent-expansion of these integrals in two different ways, with the method of Mellin-Barnes representations and sector decomposition. Finally, we present the Laurentexpansion of the full insertion operator for the specific examples of electron-positron annihilation into two and three jets. (orig.)

  17. A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the iterated singly-unresolved subtraction terms

    Science.gov (United States)

    Bolzoni, Paolo; Somogyi, Gábor; Trócsányi, Zoltán

    2011-01-01

    We perform the integration of all iterated singly-unresolved subtraction terms, as defined in ref. [1], over the two-particle factorized phase space. We also sum over the unresolved parton flavours. The final result can be written as a convolution (in colour space) of the Born cross section and an insertion operator. We spell out the insertion operator in terms of 24 basic integrals that are defined explicitly. We compute the coefficients of the Laurent expansion of these integrals in two different ways, with the method of Mellin-Barnes representations and sector decomposition. Finally, we present the Laurent-expansion of the full insertion operator for the specific examples of electron-positron annihilation into two and three jets.

  18. A novel method to remove the background from x-ray diffraction signal

    DEFF Research Database (Denmark)

    Zheng, Yi; Speller, Robert; Griffiths, Jennifer

    2018-01-01

    The first step that is required to extract the correct information from a two-dimensional (2D) diffraction signature is to remove the background accurately. However, direct background subtraction inevitably overcorrects the signal as it does not take into account the attenuation by the sample. Ot...... proposes a novel method that combines peak fitting and experimental results to estimate the background for 2D XRD signals....

  19. A new registration method with voxel-matching technique for temporal subtraction images

    Science.gov (United States)

    Itai, Yoshinori; Kim, Hyoungseop; Ishikawa, Seiji; Katsuragawa, Shigehiko; Doi, Kunio

    2008-03-01

    A temporal subtraction image, which is obtained by subtraction of a previous image from a current one, can be used for enhancing interval changes on medical images by removing most of normal structures. One of the important problems in temporal subtraction is that subtraction images commonly include artifacts created by slight differences in the size, shape, and/or location of anatomical structures. In this paper, we developed a new registration method with voxel-matching technique for substantially removing the subtraction artifacts on the temporal subtraction image obtained from multiple-detector computed tomography (MDCT). With this technique, the voxel value in a warped (or non-warped) previous image is replaced by a voxel value within a kernel, such as a small cube centered at a given location, which would be closest (identical or nearly equal) to the voxel value in the corresponding location in the current image. Our new method was examined on 16 clinical cases with MDCT images. Preliminary results indicated that interval changes on the subtraction images were enhanced considerably, with a substantial reduction of misregistration artifacts. The temporal subtraction images obtained by use of the voxel-matching technique would be very useful for radiologists in the detection of interval changes on MDCT images.

  20. Mental Computation or Standard Algorithm? Children's Strategy Choices on Multi-Digit Subtractions

    Science.gov (United States)

    Torbeyns, Joke; Verschaffel, Lieven

    2016-01-01

    This study analyzed children's use of mental computation strategies and the standard algorithm on multi-digit subtractions. Fifty-eight Flemish 4th graders of varying mathematical achievement level were individually offered subtractions that either stimulated the use of mental computation strategies or the standard algorithm in one choice and two…

  1. The Use of Procedural Knowledge in Simple Addition and Subtraction Problems

    Science.gov (United States)

    Fayol, Michel; Thevenot, Catherine

    2012-01-01

    In a first experiment, adults were asked to solve one-digit additions, subtractions and multiplications. When the sign appeared 150 ms before the operands, addition and subtraction were solved faster than when the sign and the operands appeared simultaneously on screen. This priming effect was not observed for multiplication problems. A second…

  2. Subtraction with hadronic initial states at NLO: an NNLO-compatible scheme

    Science.gov (United States)

    Somogyi, Gábor

    2009-05-01

    We present an NNLO-compatible subtraction scheme for computing QCD jet cross sections of hadron-initiated processes at NLO accuracy. The scheme is constructed specifically with those complications in mind, that emerge when extending the subtraction algorithm to next-to-next-to-leading order. It is therefore possible to embed the present scheme in a full NNLO computation without any modifications.

  3. Subtraction with hadronic initial states at NLO: an NNLO-compatible scheme

    International Nuclear Information System (INIS)

    Somogyi, Gabor

    2009-01-01

    We present an NNLO-compatible subtraction scheme for computing QCD jet cross sections of hadron-initiated processes at NLO accuracy. The scheme is constructed specifically with those complications in mind, that emerge when extending the subtraction algorithm to next-to-next-to-leading order. It is therefore possible to embed the present scheme in a full NNLO computation without any modifications.

  4. The digital subtraction technique in lateral urethrocystography. Die laterale Urethrozystographie in digitaler Subtraktionstechnik

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, K. (Radiologische Abt., Caritas-Krankenhaus, Bad Mergentheim (Germany)); Peterseim, H. (Frauenklinik, Caritas-Krankenhaus, Bad Mergentheim (Germany)); Grehn, S. (Radiologische Abt., Caritas-Krankenhaus, Bad Mergentheim (Germany))

    1994-09-01

    The first application of the digital subtraction technique to lateral urethrocystography is described. This methodology facilitates gynecological-urological operations by providing reliable investigation results and an unambiguous image interpretation. Methods and first experiences with the digital subtraction technique in gynecological-urological diagnosis are reported. (orig.)

  5. Incidence of ischemic lesions in diffusion-weighted imaging after transbrachial digital subtraction angiography

    International Nuclear Information System (INIS)

    Aschenbach, R.; Majeed, A.; Eger, C.; Basche, S.; Kerl, J.M.; Vogl, T.J.

    2008-01-01

    Purpose: to evaluate the frequency of ischemia after transbrachial digital subtraction angiography under ambulant conditions using diffusion-weighted imaging. Materials and methods: 200 patients were included in a prospective study design and received transbrachial digital subtraction angiography under ambulant conditions. Before and after digital subtraction angiography, diffusion-weighted imaging of the brain was performed. Results: in our study population no new lesions were found in diffusion-weighted imaging after digital subtraction angiography during the 3-hour window after angiography. One new lesion was found 3 days after angiography as a late onset complication. Therefore, the frequency of neurological complications is at the level of the confidence interval of 0 - 1.5%. Conclusion: the transbrachial approach under ambulant conditions is a safe method for digital subtraction angiography resulting in a low rate of ischemic lesions in diffusion-weighted imaging. (orig.)

  6. A study on the geometric correction for the digital subtraction radiograph

    International Nuclear Information System (INIS)

    Lim, Suk Young; Koh, Kwang Joon

    2001-01-01

    To develop a new subtraction program for registering digital images based on the correspondence of anatomic structures. The digital periapical images were obtained by Digora system with Rinn XCP equipment after translation of 1-16 mm, and rotation of 2-20 at the premolar and molar areas of the human dried mandible. The new subtraction program, NIH Image program and Emago/Advanced program were compared by the peak-signal -to noise ratio (PSNR). The new subtraction program was superior to NIH Images program and Emago/Advanced program up to 16 mm translation and horizontal angulation up to 4. The new subtraction program can be used for subtracting digital periapical images

  7. The study of myocardial ischemic quality with weighted-subtraction-bull's-eye analysis

    International Nuclear Information System (INIS)

    Chen Wuduan; Tian Jiahe; Hou Qingtian

    1993-01-01

    Weighted-Subtraction-Bull's-eye analysis was studied in 33 normal subjects and 58 patients with coronary artery disease after dipyridamole 99m Tc-MIBI myocardial SPECT imaging. Two kinds of Bull's-eye were produced: (1) subtract rest from 1.2 times dipyridamole from 1.2 times rest Bull's-eye; (2) subtract dipyridamole Bull's-eye. The results showed that the weighted-subtraction-Bull's-eye could clearly displayed the location and puality of ischemic myocardium. And also 74% segments showed so called combined ischemic i.e the blood perfusion reduced, increased and sustained simultaneously after dipyridamole. Therefore weighted-subtraction-Bull's-eye analysis had provided a new method for determination of the quality of ischemia

  8. Robustness in econometrics

    CERN Document Server

    Sriboonchitta, Songsak; Huynh, Van-Nam

    2017-01-01

    This book presents recent research on robustness in econometrics. Robust data processing techniques – i.e., techniques that yield results minimally affected by outliers – and their applications to real-life economic and financial situations are the main focus of this book. The book also discusses applications of more traditional statistical techniques to econometric problems. Econometrics is a branch of economics that uses mathematical (especially statistical) methods to analyze economic systems, to forecast economic and financial dynamics, and to develop strategies for achieving desirable economic performance. In day-by-day data, we often encounter outliers that do not reflect the long-term economic trends, e.g., unexpected and abrupt fluctuations. As such, it is important to develop robust data processing techniques that can accommodate these fluctuations.

  9. Robust Manufacturing Control

    CERN Document Server

    2013-01-01

    This contributed volume collects research papers, presented at the CIRP Sponsored Conference Robust Manufacturing Control: Innovative and Interdisciplinary Approaches for Global Networks (RoMaC 2012, Jacobs University, Bremen, Germany, June 18th-20th 2012). These research papers present the latest developments and new ideas focusing on robust manufacturing control for global networks. Today, Global Production Networks (i.e. the nexus of interconnected material and information flows through which products and services are manufactured, assembled and distributed) are confronted with and expected to adapt to: sudden and unpredictable large-scale changes of important parameters which are occurring more and more frequently, event propagation in networks with high degree of interconnectivity which leads to unforeseen fluctuations, and non-equilibrium states which increasingly characterize daily business. These multi-scale changes deeply influence logistic target achievement and call for robust planning and control ...

  10. Robust plasmonic substrates

    DEFF Research Database (Denmark)

    Kostiučenko, Oksana; Fiutowski, Jacek; Tamulevicius, Tomas

    2014-01-01

    Robustness is a key issue for the applications of plasmonic substrates such as tip-enhanced Raman spectroscopy, surface-enhanced spectroscopies, enhanced optical biosensing, optical and optoelectronic plasmonic nanosensors and others. A novel approach for the fabrication of robust plasmonic...... substrates is presented, which relies on the coverage of gold nanostructures with diamond-like carbon (DLC) thin films of thicknesses 25, 55 and 105 nm. DLC thin films were grown by direct hydrocarbon ion beam deposition. In order to find the optimum balance between optical and mechanical properties...

  11. Robust Self Tuning Controllers

    DEFF Research Database (Denmark)

    Poulsen, Niels Kjølstad

    1985-01-01

    The present thesis concerns robustness properties of adaptive controllers. It is addressed to methods for robustifying self tuning controllers with respect to abrupt changes in the plant parameters. In the thesis an algorithm for estimating abruptly changing parameters is presented. The estimator...... has several operation modes and a detector for controlling the mode. A special self tuning controller has been developed to regulate plant with changing time delay.......The present thesis concerns robustness properties of adaptive controllers. It is addressed to methods for robustifying self tuning controllers with respect to abrupt changes in the plant parameters. In the thesis an algorithm for estimating abruptly changing parameters is presented. The estimator...

  12. Comparison of conventional panoramic radiography and panoramic digital subtraction radiography in detection of simulated lesions of mandibular condyle

    Directory of Open Access Journals (Sweden)

    Panjnoush M.

    2008-12-01

    Full Text Available "n  "nBackground and Aim: Digital subtraction Radiography (DSR is a method of accurate assessing condylar head changes. several studies have been carried out in applying DSR in dentistry, however there is a few number of studies in efficacy of DSR method in assesment of condylar head changes, The aim of this study was to compare panoramic radiography and DSR detecting simulated lesions of the mandibular condyl. "nMaterials and Methods: this was a process reaserch study, in which two dry human skulls with no obvious temporomandibular joint pathology were used. Osteophytic lesions were simulated using three sizes of bone chips that were placed on the medial portion of anterior and superolateral aspects of the condyle. Osteolytic lesions were simulated making 1 and 2 mm holes using round burr in the central portion of anterior aspect and Lateral pole of the condyle. Panoramic radiographs were prepared with and without the lesions in place. These paired radiographs were digitized and digital- subtraction images of the original panoramic images were obtained. Eight observers evaluated 155 images of each modality for the presence or absence and the type of simulated lesions of the mandibular condyle. Sensitivity, specificity, reliability and measure of agreement were analyzed using kappa test and crossed tables and qualitative variables were assess by chi-square and fisher's Exact test. "nResults: Specificity of panoramic and DSR methods were 15.4% and 66.7% respectively. Sensitivity of panoramic and DSR methods were 61.1% and 80.6% for osteophytic lesions and 37.5% and 83.3% for Osteolytic lesions. The percentage of correct decisions made in DSR method was significantly more than conventional panoramic method (82.6% vs 41.9% (p<0.0001. "nConclusion: Based on the results of this study digital subtraction technique was significantly more accurate than the panoramic radiographs in detection of simulated lesions of the mandibular condyle.

  13. DeepAnomaly: Combining Background Subtraction and Deep Learning for Detecting Obstacles and Anomalies in an Agricultural Field

    Directory of Open Access Journals (Sweden)

    Peter Christiansen

    2016-11-01

    Full Text Available Convolutional neural network (CNN-based systems are increasingly used in autonomous vehicles for detecting obstacles. CNN-based object detection and per-pixel classification (semantic segmentation algorithms are trained for detecting and classifying a predefined set of object types. These algorithms have difficulties in detecting distant and heavily occluded objects and are, by definition, not capable of detecting unknown object types or unusual scenarios. The visual characteristics of an agriculture field is homogeneous, and obstacles, like people, animals and other obstacles, occur rarely and are of distinct appearance compared to the field. This paper introduces DeepAnomaly, an algorithm combining deep learning and anomaly detection to exploit the homogenous characteristics of a field to perform anomaly detection. We demonstrate DeepAnomaly as a fast state-of-the-art detector for obstacles that are distant, heavily occluded and unknown. DeepAnomaly is compared to state-of-the-art obstacle detectors including “Faster R-CNN: Towards Real-Time Object Detection with Region Proposal Networks” (RCNN. In a human detector test case, we demonstrate that DeepAnomaly detects humans at longer ranges (45–90 m than RCNN. RCNN has a similar performance at a short range (0–30 m. However, DeepAnomaly has much fewer model parameters and (182 ms/25 ms = a 7.28-times faster processing time per image. Unlike most CNN-based methods, the high accuracy, the low computation time and the low memory footprint make it suitable for a real-time system running on a embedded GPU (Graphics Processing Unit.

  14. Bone marrow edema pattern identification in patients with lytic bone lesions using digital subtraction angiography-like bone subtraction on large-area detector computed tomography.

    Science.gov (United States)

    Gondim Teixeira, Pedro Augusto; Hossu, Gabriela; Lecocq, Sophie; Razeto, Marco; Louis, Matthias; Blum, Alain

    2014-03-01

    The objective of this study was to evaluate the performance of digital subtraction angiography (DSA)-like bone subtraction with 2 different registration methods for the identification of bone marrow edema pattern (BMEP) in patients with lytic bone lesions, using magnetic resonance imaging as the criterion standard. Fifty-five patients with a lytic bone lesion were included in this prospective study with approval from the ethics committee. All patients underwent magnetic resonance imaging and low-dose computed tomographic (CT) perfusion after signing an informed consent. Two CT volumes were used for bone subtraction, which was performed with 2 different algorithms (rigid and nonrigid). Enhancement at the nonlytic bone marrow was considered as a sign of BMEP. Two readers evaluated the images blindly. The presence of BMEP on bone-subtracted CT images was evaluated subjectively and quantitatively. Image quality was assessed. Magnetic resonance imaging was used as the criterion standard. Using a rigid registration method, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CT with DSA-like bone subtraction BMEP was 77%, 100%, 100%, 68%, and 85%, respectively. The interobserver agreement was good (κ, 0.782). Image quality was better using a nonrigid registration. With this algorithm, artifacts interfered with image interpretation in only 5% of cases. However, there was a noticeable drop in sensitivity and negative predictive value when a nonrigid algorithm was used: 56% and 52%, respectively. The interobserver agreement was average with a nonrigid subtraction algorithm. Computed tomography with DSA-like bone subtraction is sensitive and highly specific for the identification of BMEP associated with lytic bone lesions. Rigid registering should be preferred, but nonrigid algorithms can be used as a second option when artifacts interfere with image interpretation.

  15. Robust surgery loading

    NARCIS (Netherlands)

    Hans, Elias W.; Wullink, Gerhard; van Houdenhoven, Mark; Kazemier, Geert

    2008-01-01

    We consider the robust surgery loading problem for a hospital’s operating theatre department, which concerns assigning surgeries and sufficient planned slack to operating room days. The objective is to maximize capacity utilization and minimize the risk of overtime, and thus cancelled patients. This

  16. Robustness Envelopes of Networks

    NARCIS (Netherlands)

    Trajanovski, S.; Martín-Hernández, J.; Winterbach, W.; Van Mieghem, P.

    2013-01-01

    We study the robustness of networks under node removal, considering random node failure, as well as targeted node attacks based on network centrality measures. Whilst both of these have been studied in the literature, existing approaches tend to study random failure in terms of average-case

  17. Image noise reduction algorithm for digital subtraction angiography: clinical results.

    Science.gov (United States)

    Söderman, Michael; Holmin, Staffan; Andersson, Tommy; Palmgren, Charlotta; Babic, Draženko; Hoornaert, Bart

    2013-11-01

    To test the hypothesis that an image noise reduction algorithm designed for digital subtraction angiography (DSA) in interventional neuroradiology enables a reduction in the patient entrance dose by a factor of 4 while maintaining image quality. This clinical prospective study was approved by the local ethics committee, and all 20 adult patients provided informed consent. DSA was performed with the default reference DSA program, a quarter-dose DSA program with modified acquisition parameters (to reduce patient radiation dose exposure), and a real-time noise-reduction algorithm. Two consecutive biplane DSA data sets were acquired in each patient. The dose-area product (DAP) was calculated for each image and compared. A randomized, blinded, offline reading study was conducted to show noninferiority of the quarter-dose image sets. Overall, 40 samples per treatment group were necessary to acquire 80% power, which was calculated by using a one-sided α level of 2.5%. The mean DAP with the quarter-dose program was 25.3% ± 0.8 of that with the reference program. The median overall image quality scores with the reference program were 9, 13, and 12 for readers 1, 2, and 3, respectively. These scores increased slightly to 12, 15, and 12, respectively, with the quarter-dose program imaging chain. In DSA, a change in technique factors combined with a real-time noise-reduction algorithm will reduce the patient entrance dose by 75%, without a loss of image quality. RSNA, 2013

  18. Identification of formaldehyde-responsive genes by suppression subtractive hybridization

    International Nuclear Information System (INIS)

    Lee, Min-Ho; Kim, Young-Ae; Na, Tae-Young; Kim, Sung-Hye; Shin, Young Kee; Lee, Byung-Hoon; Shin, Ho-Sang; Lee, Mi-Ock

    2008-01-01

    Formaldehyde is frequently used in indoor household and occupational environments. Inhalation of formaldehyde invokes an inflammatory response, including a variety of allergic signs and symptoms. Therefore, formaldehyde has been considered as the most prevalent cause of sick building syndrome, which has become a major social problem, especially in developing urban areas. Further formaldehyde is classified as a genotoxicant in the respiratory tract of rats and humans. To better understand the molecular mechanisms involved in formaldehyde intoxication, we sought differentially regulated genes by formaldehyde exposure to Hs 680.Tr human trachea cells, using polymerase chain reaction (PCR)-based suppression subtractive hybridization. We identified 27 different formaldehyde-inducible genes, including those coding for the major histocompatibility complex, class IA, calcyclin, glutathione S-transferase pi, mouse double minute 2 (MDM2), platelet-derived growth factor receptor alpha, and which are known to be associated with cell proliferation and differentiation, immunity and inflammation, and detoxification. Induction of these genes by formaldehyde treatment was confirmed by reverse transcription PCR and western blot analysis. Further, the expression of calcyclin, glutathione S-transferase pi, PDGFRA and MDM2 were significantly induced in the tracheal epithelium of Sprague Dawley rats after formaldehyde inhalation. Our results suggest that the elevated levels of these genes may be associated with the formaldehyde-induced toxicity, and that they deserve evaluation as potential biomarkers for formaldehyde intoxication

  19. Radiation doses to patients from digital subtraction angiography

    International Nuclear Information System (INIS)

    Goni, H.; Tsalafoutas, I. A.; Tzortzis, G.; Pappas, P.; Bouzas, N.; Loulakas, J.; Georgiou, A.; Georgiou, E.; Yakoumakis, E. N.

    2005-01-01

    This investigation determined patient doses during digital subtraction angiography (DSA). Fluoroscopy time, dose-area product (DAP) and entrance surface air kerma (ESAK) were analysed from 263 DSA examinations, classified into seven categories: (1) abdominal aorta, iliac, femoral, popliteal and leg arteries; (2) abdominal aorta and super-selective DSA of renal arteries; (3) combination of (1) and (2); (4) super-selective DSA of common carotid and vertebral arteries, intracranial branches in face and profile projections; (5) super-selective DSA of hepatic, splenic, superior and inferior mesenteric arteries; (6) combination of (1) and (4); and (7) celiac trunk and branches. Median DAP values were 67.7, 92.9, 76.6, 53.6, 105.7, 76.1 and 2.6 Gy cm 2 , respectively. With the exception of one examination, ESAK values were below 2 Gy: the limit for erythema. Compared with published data, DAP values were within the range reported for (1) and (4), slightly larger for (2) and (5), whereas no references were identified for the remaining three categories. (authors)

  20. A case of aortitis syndrome diagnosed by digital subtraction angiography

    International Nuclear Information System (INIS)

    Tamaki, Atsushi; Sakai, Masashi; Yano, Kimio

    1984-01-01

    A 45-year-old female was admitted to our hospital with complaints of anemia, hypertension, and a dull, throbbing pain in the right side of the neck. On physical examination, a pulsating tumor in the right side of the neck and a ''to-and-fro'' murmur at the right 2nd intercostal space were noted. Laboratory tests revealed ESR 90 mm/hour and CRP 5+. Digital subtraction angiography (DSA) showed an aneurysm distal to the narrowing of the right common carotid artery, in addition to winding and narrowing of the right vertebral and the left common carotid arteries. These findings are typical of Type I aortitis syndrome. Aortogram showed aortic regurgitation (AR). Furthermore, we found the presence of HLA Bw52 and a conspicuous increase of tromboxane B 2 . Treatment involving a combination of prednisolone, azathioprine and estriol was effective, resulting in marked improvement of the patient's general condition as well as laboratory test results. In cases of aortitis syndrome combined with an aneurysm of a large artery and AR, direct opacification of the aorta with a catheter is occasionally hazardous and is difficult to perform repeatedly. DSA is useful in such circumstances because it can be performed repeatedly with little risk and it offers an image as clear as these obtained by direct injection of contrast medium in the aorta. (author)

  1. Robotic digital subtraction angiography systems within the hybrid operating room.

    Science.gov (United States)

    Murayama, Yuichi; Irie, Koreaki; Saguchi, Takayuki; Ishibashi, Toshihiro; Ebara, Masaki; Nagashima, Hiroyasu; Isoshima, Akira; Arakawa, Hideki; Takao, Hiroyuki; Ohashi, Hiroki; Joki, Tatsuhiro; Kato, Masataka; Tani, Satoshi; Ikeuchi, Satoshi; Abe, Toshiaki

    2011-05-01

    Fully equipped high-end digital subtraction angiography (DSA) within the operating room (OR) environment has emerged as a new trend in the fields of neurosurgery and vascular surgery. To describe initial clinical experience with a robotic DSA system in the hybrid OR. A newly designed robotic DSA system (Artis zeego; Siemens AG, Forchheim, Germany) was installed in the hybrid OR. The system consists of a multiaxis robotic C arm and surgical OR table. In addition to conventional neuroendovascular procedures, the system was used as an intraoperative imaging tool for various neurosurgical procedures such as aneurysm clipping and spine instrumentation. Five hundred one neurosurgical procedures were successfully conducted in the hybrid OR with the robotic DSA. During surgical procedures such as aneurysm clipping and arteriovenous fistula treatment, intraoperative 2-/3-dimensional angiography and C-arm-based computed tomographic images (DynaCT) were easily performed without moving the OR table. Newly developed virtual navigation software (syngo iGuide; Siemens AG) can be used in frameless navigation and in access to deep-seated intracranial lesions or needle placement. This newly developed robotic DSA system provides safe and precise treatment in the fields of endovascular treatment and neurosurgery.

  2. Intravenous digital subtraction angiography contrast media time-concentration curves

    International Nuclear Information System (INIS)

    Burbank, F.H.; Brody, W.R.

    1985-01-01

    At any specified radiation dose and system signal-to-noise ratio, temporal (masked-mode) intravenous digital subtraction angiography (IV-DSA) image quality is dependent upon the shape of the arterial time-concentration curve produced by the intravenous injection of iodinated contrast media. If contrast media appears in the arterial circulation as a compact bolus and reaches a high peak, images containing low or no iodine (the mask image or images) and high iodine concentration (the enhanced image or images) can be obtained close together in time, maximizing contrast media enhancement and minimizing the potential for spatial movement (misregistration). However, if the contrast media bolus is broad, rising slowly to a low concentration peak, sufficient time may pass for movement to occur and the opacification difference between the mask image and the enhanced image may be too small to visualize vessels of interest. Consequently, knowledge of the rules which govern the formation of time-concentration curves is central to IV-DSA

  3. Evaluation of left ventricular function using digital subtraction angiography

    International Nuclear Information System (INIS)

    Kozuka, Takahiro; Ohta, Mitsushige

    1985-01-01

    To evaluate function of the left ventricle and myocardial perfusion images, digital subtraction angiography (DSA) was performed in 45 patients with ischemic heart disease. Validity of the technique was compared with data obtained from cine left ventriculogram in all patients and 201 T1 myocardial images in 20 patients. End-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) calculated from DSA were correlated closely with those from cine left ventriculogram (r = 0.92, r = 0.94 and r = 0.86, respectively). Regional contractility at the antero-lateral wall of the left ventricle, assessed by DSA, was also correlated well with cine left ventriculogram (r = 0.75). Evaluation of the inferior wall motion showed less correlation in both procedures (r = 0.68). Phase and amplitude analysis with the same technique with radionuclide cardiac angiography was successfully applied in left ventriculogram obtained by DSA. The procedure seems to be helpful for objective evaluation of the left ventricular wall motion. Myocardial perfusion image, obtained with modified Radtke's technique, showed good coincidence with 201 T1 images. Thus, DSA is applicable for evaluation of function of the left ventricle and myocardial perfusion in patients with ischemic heart disease. (author)

  4. Matching the quasiparton distribution in a momentum subtraction scheme

    Science.gov (United States)

    Stewart, Iain W.; Zhao, Yong

    2018-03-01

    The quasiparton distribution is a spatial correlation of quarks or gluons along the z direction in a moving nucleon which enables direct lattice calculations of parton distribution functions. It can be defined with a nonperturbative renormalization in a regularization independent momentum subtraction scheme (RI/MOM), which can then be perturbatively related to the collinear parton distribution in the MS ¯ scheme. Here we carry out a direct matching from the RI/MOM scheme for the quasi-PDF to the MS ¯ PDF, determining the non-singlet quark matching coefficient at next-to-leading order in perturbation theory. We find that the RI/MOM matching coefficient is insensitive to the ultraviolet region of convolution integral, exhibits improved perturbative convergence when converting between the quasi-PDF and PDF, and is consistent with a quasi-PDF that vanishes in the unphysical region as the proton momentum Pz→∞ , unlike other schemes. This direct approach therefore has the potential to improve the accuracy for converting quasidistribution lattice calculations to collinear distributions.

  5. Experience with digital subtraction angiography of cervicocranial region

    International Nuclear Information System (INIS)

    Bohutova, J.; Neuwirth, J.; Kuncova, S.; Lerlova, L.

    1988-01-01

    Digital subtraction angiography (DSA) of the head was performed in 100 patients for mostly neurological indications, less frequently pathological processes in the region of the external carotid artery. The intravenous or intraarterial route was selected according to the condition and age of the patient and clinical diagnosis. In 55% of cases the contrast medium was administered into the ascending aorta, in 13% selectively into the carotid or vertebral arteries. The examination was performed intravenously in 32%, most frequently via inferior vena cava (26%). The visualization of the whole area of the carotid and vertebral arteries from the ramification of the aortal arc up to the periphery requires to make at least 4 to 5 administrations of contrast medium, since simultaneous representation of lateral and AP projection for DSA has not been so far possible and the screen size is small. In intravenous DSA the amount of contrast medium increases up to 200 ml. Instillation into the ascending artery is therefore preferred and half of the amount is thus sufficient. DSA has proved of advantage in the examination of patients with arteriosclerosis, angiomas and arteriovenous malformations, vascularized and avascular expansive processes in intracranial and extracranial localizations. Quality angiograms were obtained in 84%, those still suitable for evaluation in 14% and useless in 2% of cases. (author). 14 figs., 1 tab., 16 refs

  6. Adaptive Critic Nonlinear Robust Control: A Survey.

    Science.gov (United States)

    Wang, Ding; He, Haibo; Liu, Derong

    2017-10-01

    Adaptive dynamic programming (ADP) and reinforcement learning are quite relevant to each other when performing intelligent optimization. They are both regarded as promising methods involving important components of evaluation and improvement, at the background of information technology, such as artificial intelligence, big data, and deep learning. Although great progresses have been achieved and surveyed when addressing nonlinear optimal control problems, the research on robustness of ADP-based control strategies under uncertain environment has not been fully summarized. Hence, this survey reviews the recent main results of adaptive-critic-based robust control design of continuous-time nonlinear systems. The ADP-based nonlinear optimal regulation is reviewed, followed by robust stabilization of nonlinear systems with matched uncertainties, guaranteed cost control design of unmatched plants, and decentralized stabilization of interconnected systems. Additionally, further comprehensive discussions are presented, including event-based robust control design, improvement of the critic learning rule, nonlinear H ∞ control design, and several notes on future perspectives. By applying the ADP-based optimal and robust control methods to a practical power system and an overhead crane plant, two typical examples are provided to verify the effectiveness of theoretical results. Overall, this survey is beneficial to promote the development of adaptive critic control methods with robustness guarantee and the construction of higher level intelligent systems.

  7. Introduction to Robust Estimation and Hypothesis Testing

    CERN Document Server

    Wilcox, Rand R

    2012-01-01

    This revised book provides a thorough explanation of the foundation of robust methods, incorporating the latest updates on R and S-Plus, robust ANOVA (Analysis of Variance) and regression. It guides advanced students and other professionals through the basic strategies used for developing practical solutions to problems, and provides a brief background on the foundations of modern methods, placing the new methods in historical context. Author Rand Wilcox includes chapter exercises and many real-world examples that illustrate how various methods perform in different situations.Introduction to R

  8. Experimental determination of the weighting factor for the energy window subtraction-based downscatter correction for I-123 in brain SPECT studies

    DEFF Research Database (Denmark)

    de Nijs, Robin; Holm, Søren; Thomsen, Gerda

    2010-01-01

    Correction for downscatter in I-123 SPECT can be performed by the subtraction of a secondary energy window from the main window, as in the triple-energy window method. This is potentially noise sensitive. For studies with limited amount of counts (e.g. dynamic studies), a broad subtraction window...... were investigated in this study. Energy windows with a width of 32 keV were centered at 159 keV and 200 keV. The weighting factor was measured both with an I-123 point source and in a dopamine transporter brain SPECT study in 10 human subjects (5 healthy subjects and 5 patients) by minimizing...... the background outside the head. Weighting factors ranged from 1.11 to 1.13 for the point source and from 1.16 to 1.18 for human subjects. Point source measurements revealed no position dependence. After correction, the measured specific binding ratio (image contrast) increased significantly for healthy subjects...

  9. Late iodine enhancement computed tomography with image subtraction for assessment of myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Tanabe, Yuki; Kido, Teruhito; Kurata, Akira; Kouchi, Takanori; Fukuyama, Naoki; Yokoi, Takahiro; Miyagawa, Masao; Mochizuki, Teruhito [Ehime University Graduate School of Medicine, Department of Radiology, Toon City, Ehime (Japan); Uetani, Teruyoshi [Department of Cardiology, Ehime University Graduate School of Medicine, Toon City, Ehime (Japan); Yamashita, Natsumi [National Hospital Organization Shikoku Cancer Center, Department of Clinical Biostatistics, Section of Cancer Prevention and Epidemiology, Clinical Research Center, Matsuyama City, Ehime (Japan)

    2018-03-15

    To evaluate the feasibility of image subtraction in late iodine enhancement CT (LIE-CT) for assessment of myocardial infarction (MI). A comprehensive cardiac CT protocol and late gadolinium enhancement MRI (LGE-MRI) was used to assess coronary artery disease in 27 patients. LIE-CT was performed after stress CT perfusion (CTP) and CT angiography. Subtraction LIE-CT was created by subtracting the mask volume of the left ventricle (LV) cavity from the original LIE-CT using CTP dataset. The %MI volume was quantified as the ratio of LIE to entire LV volume, and transmural extent (TME) of LIE was classified as 0%, 1-24%, 25-49%, 50-74% or 75-100%. These results were compared with LGE-MRI using the Spearman rank test, Bland-Altman method and chi-square test. One hundred twenty-five (29%) of 432 segments were positive on LGE-MRI. Correlation coefficients for original and subtraction LIE-CT to LGE-MRI were 0.79 and 0.85 for %MI volume. Concordances of the 5-point grading scale between original and subtraction LIE-CT with LGE-MRI were 75% and 84% for TME; concordance was significantly improved using the subtraction technique (p <0.05). Subtraction LIE-CT allowed more accurate assessment of MI extent than the original LIE-CT. (orig.)

  10. Identification of Bacillus anthracis specific chromosomal sequences by suppressive subtractive hybridization

    Directory of Open Access Journals (Sweden)

    Redkar Rajendra

    2004-02-01

    Full Text Available Abstract Background Bacillus anthracis, Bacillus thuringiensis and Bacillus cereus are closely related members of the B. cereus-group of bacilli. Suppressive subtractive hybridization (SSH was used to identify specific chromosomal sequences unique to B. anthracis. Results Two SSH libraries were generated. Genomic DNA from plasmid-cured B. anthracis was used as the tester DNA in both libraries, while genomic DNA from either B. cereus or B. thuringiensis served as the driver DNA. Progressive screening of the libraries by colony filter and Southern blot analyses identified 29 different clones that were specific for the B. anthracis chromosome relative not only to the respective driver DNAs, but also to seven other different strains of B. cereus and B. thuringiensis included in the process. The nucleotide sequences of the clones were compared with those found in genomic databases, revealing that over half of the clones were located into 2 regions on the B. anthracis chromosome. Conclusions Genes encoding potential cell wall synthesis proteins dominated one region, while bacteriophage-related sequences dominated the other region. The latter supports the hypothesis that acquisition of these bacteriophage sequences occurred during or after speciation of B. anthracis relative to B. cereus and B. thuringiensis. This study provides insight into the chromosomal differences between B. anthracis and its closest phylogenetic relatives.

  11. Femoral head vascularisation in Legg-Calve-Perthes disease: comparison of dynamic gadolinium-enhanced subtraction MRI with bone scintigraphy

    International Nuclear Information System (INIS)

    Lamer, Sylvie; Dorgeret, Sophie; Brillet, Pierre-Yves; Hassan, Max; Sebag, Guy H.; Khairouni, Abdeslam; Mazda, Keyvan; Bacheville, Eric; Pennecot, Georges F.; Bloch, Juliette

    2002-01-01

    Heading AbstractBackground. It has been reported that MRI using a dynamic gadolinium-enhanced subtraction technique can allow the early identification of ischaemia and the pattern of revascularisation in Legg-Calve-Perthes (LCP) disease with increased spatial and contrast resolution. Therefore, dynamic gadolinium-enhanced subtraction (DGS) MRI may be a possible non-ionising substitute for bone scintigraphy.Objective. The purpose of this prospective study was to compare DGS MRI and bone scintigraphy in the assessment of femoral head perfusion in LCP disease.Materials and methods. Twenty-six DGS MR images and bone scintigraphies of 25 hips in 23 children were obtained at different stages of LCP disease; three stage I, 12 stage II, six stage III and five stage IV (Waldenstroem classification). The extent of necrosis, epiphyseal revascularisation pathways (lateral pillar, medial pillar, and/or transphyseal perfusion) and metaphyseal changes were analysed.Results. Total agreement between both techniques was noted in the depiction of epiphyseal necrosis (kappa=1), and metaphyseal abnormalities (kappa=0.9). DGS MRI demonstrated better revascularisation in the lateral (kappa=0.62) and medial pillars (kappa=0.52). The presence of basal transphyseal reperfusion was more conspicuous with MRI.Conclusions. DGS MRI allows early detection of epiphyseal ischaemia and accurate analysis of the different revascularisation patterns. These changes are directly related to the prognosis of LCP disease and can aid therapeutic decision making. (orig.)

  12. Preliminary study of lateral cerebral angiography with reverse rotation in the digital image registration and subtraction

    International Nuclear Information System (INIS)

    Shen Zhenglin; Liu Dongyang; Shen Zhenghai; Li Shuping; Zhang Ziyan; Wu Yongjuan; Liu Peijun

    2012-01-01

    Objective: Investigate the value and feasibility of image registration with reverse rotation in lateral cerebral DSA. Methods: (1) Experimental study: the target images were subtracted directly, and subtracted again after reverse rotation. Software of registration and subtraction with reverse rotation edited by the author utilizing Visual Basic. The function of the automatic angle detection by the software were evaluated to see whether it detected the angle of line. The subtraction function of DSA by the software was evaluated. (2) Clinical retrospective study: the untreated mask and target images of 15 patients with motion along vertical axis during lateral cerebral DSA were uploaded to the software. The target images were processed with and without the software to get two sets of images. (3) Evaluation: four experienced radiologists read and compared the two sets of the images,and graded their findings. Results: (1) The automatic detection by the software suggested that the target images should be rotated counterclockwise 1.3°. The subtraction result of the software was satisfactory. (2) In the 15 sets of images, there were only three sets of images deemed optimal after traditional subtraction. After reverse rotation, artifacts were significantly reduced and the image sharper. There were ten cases with significant artifacts after traditional subtraction, and those images were sharper and showed more peripheral vessels after reverse rotation. The traditional subtraction images of two sets could not be interpreted,the reverse rotation registration images reached the diagnostic quality. (3) Subjective evaluation: there were more information and less noise and distortion in the registration images with reverse rotation than in the traditional subtraction. But the image resolution decreased slightly after reverse rotation registration. Conclusion: The registration of digital angiography with reverse rotation can improve the image quality in lateral cerebral DSA

  13. Background sources at PEP

    International Nuclear Information System (INIS)

    Lynch, H.; Schwitters, R.F.; Toner, W.T.

    1988-01-01

    Important sources of background for PEP experiments are studied. Background particles originate from high-energy electrons and positrons which have been lost from stable orbits, γ-rays emitted by the primary beams through bremsstrahlung in the residual gas, and synchrotron radiation x-rays. The effect of these processes on the beam lifetime are calculated and estimates of background rates at the interaction region are given. Recommendations for the PEP design, aimed at minimizing background are presented. 7 figs., 4 tabs

  14. Quantitative blood flow measurements in the small animal cardiopulmonary system using digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Lin Mingde; Marshall, Craig T.; Qi, Yi; Johnston, Samuel M.; Badea, Cristian T.; Piantadosi, Claude A.; Johnson, G. Allan [Department of Radiology, Center for In Vivo Microscopy and Department of Biomedical Engineering, Duke University Medical Center, Box 3302, Durham, North Carolina 27710 (United States); Division of Pulmonary and Critical Care Medicine and Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Box 3823, Durham, North Carolina 27710 (United States); Department of Radiology, Center for In Vivo Microscopy, Duke University Medical Center, Box 3302, Durham, North Carolina 27710 (United States); Department of Radiology, Center for In Vivo Microscopy and Department of Biomedical Engineering, Duke University Medical Center, Box 3302, Durham, North Carolina 27710 (United States); Department of Radiology, Center for In Vivo Microscopy, Duke University Medical Center, Box 3302, Durham, North Carolina 27710 (United States); Division of Pulmonary and Critical Care Medicine and Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Box 3823, Durham, North Carolina 27710 (United States); Department of Radiology, Center for In Vivo Microscopy and Department of Biomedical Engineering, Duke University Medical Center, Box 3302, Durham, North Carolina 27710 (United States)

    2009-11-15

    Purpose: The use of preclinical rodent models of disease continues to grow because these models help elucidate pathogenic mechanisms and provide robust test beds for drug development. Among the major anatomic and physiologic indicators of disease progression and genetic or drug modification of responses are measurements of blood vessel caliber and flow. Moreover, cardiopulmonary blood flow is a critical indicator of gas exchange. Current methods of measuring cardiopulmonary blood flow suffer from some or all of the following limitations--they produce relative values, are limited to global measurements, do not provide vasculature visualization, are not able to measure acute changes, are invasive, or require euthanasia. Methods: In this study, high-spatial and high-temporal resolution x-ray digital subtraction angiography (DSA) was used to obtain vasculature visualization, quantitative blood flow in absolute metrics (ml/min instead of arbitrary units or velocity), and relative blood volume dynamics from discrete regions of interest on a pixel-by-pixel basis (100x100 {mu}m{sup 2}). Results: A series of calibrations linked the DSA flow measurements to standard physiological measurement using thermodilution and Fick's method for cardiac output (CO), which in eight anesthetized Fischer-344 rats was found to be 37.0{+-}5.1 ml/min. Phantom experiments were conducted to calibrate the radiographic density to vessel thickness, allowing a link of DSA cardiac output measurements to cardiopulmonary blood flow measurements in discrete regions of interest. The scaling factor linking relative DSA cardiac output measurements to the Fick's absolute measurements was found to be 18.90xCO{sub DSA}=CO{sub Fick}. Conclusions: This calibrated DSA approach allows repeated simultaneous visualization of vasculature and measurement of blood flow dynamics on a regional level in the living rat.

  15. Quantitative blood flow measurements in the small animal cardiopulmonary system using digital subtraction angiography

    International Nuclear Information System (INIS)

    Lin Mingde; Marshall, Craig T.; Qi, Yi; Johnston, Samuel M.; Badea, Cristian T.; Piantadosi, Claude A.; Johnson, G. Allan

    2009-01-01

    Purpose: The use of preclinical rodent models of disease continues to grow because these models help elucidate pathogenic mechanisms and provide robust test beds for drug development. Among the major anatomic and physiologic indicators of disease progression and genetic or drug modification of responses are measurements of blood vessel caliber and flow. Moreover, cardiopulmonary blood flow is a critical indicator of gas exchange. Current methods of measuring cardiopulmonary blood flow suffer from some or all of the following limitations--they produce relative values, are limited to global measurements, do not provide vasculature visualization, are not able to measure acute changes, are invasive, or require euthanasia. Methods: In this study, high-spatial and high-temporal resolution x-ray digital subtraction angiography (DSA) was used to obtain vasculature visualization, quantitative blood flow in absolute metrics (ml/min instead of arbitrary units or velocity), and relative blood volume dynamics from discrete regions of interest on a pixel-by-pixel basis (100x100 μm 2 ). Results: A series of calibrations linked the DSA flow measurements to standard physiological measurement using thermodilution and Fick's method for cardiac output (CO), which in eight anesthetized Fischer-344 rats was found to be 37.0±5.1 ml/min. Phantom experiments were conducted to calibrate the radiographic density to vessel thickness, allowing a link of DSA cardiac output measurements to cardiopulmonary blood flow measurements in discrete regions of interest. The scaling factor linking relative DSA cardiac output measurements to the Fick's absolute measurements was found to be 18.90xCO DSA =CO Fick . Conclusions: This calibrated DSA approach allows repeated simultaneous visualization of vasculature and measurement of blood flow dynamics on a regional level in the living rat.

  16. Cosmic Microwave Background Timeline

    Science.gov (United States)

    Cosmic Microwave Background Timeline 1934 : Richard Tolman shows that blackbody radiation in an will have a blackbody cosmic microwave background with temperature about 5 K 1955: Tigran Shmaonov anisotropy in the cosmic microwave background, this strongly supports the big bang model with gravitational

  17. Digital subtraction arthrography in preoperative evaluation of painful total hip arthroplasty

    International Nuclear Information System (INIS)

    Ginai, A.Z.; Biezen, F.C. van; Kint, P.A.M.; Oei, H.Y.; Hop, W.C.J.

    1996-01-01

    Digital subtraction arthrograms, scintigrams and plain radiographs of 70 consecutive patients who underwent revision hip arthroplasty were scored individually and in masked fashion for the presence or absence of features indicating loosening of femoral and/or acetabular components. The operative findings acted as the gold standard. Digital subtraction arthrography was best for predicting a loose acetabular component, while no significant additional predictive value was found for plain radiographs and scintigraphy. Digital subtraction arthrography was also the most important modality for predicting a loose femoral component, while the plain radiograph was of significant additional value and scintigraphy was of no additional value on multivariate analysis. (orig./MG)

  18. A robust classic.

    Science.gov (United States)

    Kutzner, Florian; Vogel, Tobias; Freytag, Peter; Fiedler, Klaus

    2011-01-01

    In the present research, we argue for the robustness of illusory correlations (ICs, Hamilton & Gifford, 1976) regarding two boundary conditions suggested in previous research. First, we argue that ICs are maintained under extended experience. Using simulations, we derive conflicting predictions. Whereas noise-based accounts predict ICs to be maintained (Fielder, 2000; Smith, 1991), a prominent account based on discrepancy-reducing feedback learning predicts ICs to disappear (Van Rooy et al., 2003). An experiment involving 320 observations with majority and minority members supports the claim that ICs are maintained. Second, we show that actively using the stereotype to make predictions that are met with reward and punishment does not eliminate the bias. In addition, participants' operant reactions afford a novel online measure of ICs. In sum, our findings highlight the robustness of ICs that can be explained as a result of unbiased but noisy learning.

  19. The isotropic radio background revisited

    Energy Technology Data Exchange (ETDEWEB)

    Fornengo, Nicolao; Regis, Marco [Dipartimento di Fisica Teorica, Università di Torino, via P. Giuria 1, I–10125 Torino (Italy); Lineros, Roberto A. [Instituto de Física Corpuscular – CSIC/U. Valencia, Parc Científic, calle Catedrático José Beltrán, 2, E-46980 Paterna (Spain); Taoso, Marco, E-mail: fornengo@to.infn.it, E-mail: rlineros@ific.uv.es, E-mail: regis@to.infn.it, E-mail: taoso@cea.fr [Institut de Physique Théorique, CEA/Saclay, F-91191 Gif-sur-Yvette Cédex (France)

    2014-04-01

    We present an extensive analysis on the determination of the isotropic radio background. We consider six different radio maps, ranging from 22 MHz to 2.3 GHz and covering a large fraction of the sky. The large scale emission is modeled as a linear combination of an isotropic component plus the Galactic synchrotron radiation and thermal bremsstrahlung. Point-like and extended sources are either masked or accounted for by means of a template. We find a robust estimate of the isotropic radio background, with limited scatter among different Galactic models. The level of the isotropic background lies significantly above the contribution obtained by integrating the number counts of observed extragalactic sources. Since the isotropic component dominates at high latitudes, thus making the profile of the total emission flat, a Galactic origin for such excess appears unlikely. We conclude that, unless a systematic offset is present in the maps, and provided that our current understanding of the Galactic synchrotron emission is reasonable, extragalactic sources well below the current experimental threshold seem to account for the majority of the brightness of the extragalactic radio sky.

  20. The isotropic radio background revisited

    International Nuclear Information System (INIS)

    Fornengo, Nicolao; Regis, Marco; Lineros, Roberto A.; Taoso, Marco

    2014-01-01

    We present an extensive analysis on the determination of the isotropic radio background. We consider six different radio maps, ranging from 22 MHz to 2.3 GHz and covering a large fraction of the sky. The large scale emission is modeled as a linear combination of an isotropic component plus the Galactic synchrotron radiation and thermal bremsstrahlung. Point-like and extended sources are either masked or accounted for by means of a template. We find a robust estimate of the isotropic radio background, with limited scatter among different Galactic models. The level of the isotropic background lies significantly above the contribution obtained by integrating the number counts of observed extragalactic sources. Since the isotropic component dominates at high latitudes, thus making the profile of the total emission flat, a Galactic origin for such excess appears unlikely. We conclude that, unless a systematic offset is present in the maps, and provided that our current understanding of the Galactic synchrotron emission is reasonable, extragalactic sources well below the current experimental threshold seem to account for the majority of the brightness of the extragalactic radio sky

  1. Robust Airline Schedules

    OpenAIRE

    Eggenberg, Niklaus; Salani, Matteo; Bierlaire, Michel

    2010-01-01

    Due to economic pressure industries, when planning, tend to focus on optimizing the expected profit or the yield. The consequence of highly optimized solutions is an increased sensitivity to uncertainty. This generates additional "operational" costs, incurred by possible modifications of the original plan to be performed when reality does not reflect what was expected in the planning phase. The modern research trend focuses on "robustness" of solutions instead of yield or profit. Although ro...

  2. The Crane Robust Control

    Directory of Open Access Journals (Sweden)

    Marek Hicar

    2004-01-01

    Full Text Available The article is about a control design for complete structure of the crane: crab, bridge and crane uplift.The most important unknown parameters for simulations are burden weight and length of hanging rope. We will use robustcontrol for crab and bridge control to ensure adaptivity for burden weight and rope length. Robust control will be designed for current control of the crab and bridge, necessary is to know the range of unknown parameters. Whole robust will be splitto subintervals and after correct identification of unknown parameters the most suitable robust controllers will be chosen.The most important condition at the crab and bridge motion is avoiding from burden swinging in the final position. Crab and bridge drive is designed by asynchronous motor fed from frequency converter. We will use crane uplift with burden weightobserver in combination for uplift, crab and bridge drive with cooperation of their parameters: burden weight, rope length and crab and bridge position. Controllers are designed by state control method. We will use preferably a disturbance observerwhich will identify burden weight as a disturbance. The system will be working in both modes at empty hook as well asat maximum load: burden uplifting and dropping down.

  3. Removing Background Noise with Phased Array Signal Processing

    Science.gov (United States)

    Podboy, Gary; Stephens, David

    2015-01-01

    Preliminary results are presented from a test conducted to determine how well microphone phased array processing software could pull an acoustic signal out of background noise. The array consisted of 24 microphones in an aerodynamic fairing designed to be mounted in-flow. The processing was conducted using Functional Beam forming software developed by Optinav combined with cross spectral matrix subtraction. The test was conducted in the free-jet of the Nozzle Acoustic Test Rig at NASA GRC. The background noise was produced by the interaction of the free-jet flow with the solid surfaces in the flow. The acoustic signals were produced by acoustic drivers. The results show that the phased array processing was able to pull the acoustic signal out of the background noise provided the signal was no more than 20 dB below the background noise level measured using a conventional single microphone equipped with an aerodynamic forebody.

  4. An EPIC Tale of the Quiescent Particle Background

    Science.gov (United States)

    Snowden, S.L.; Kuntz, K.D.

    2017-01-01

    Extended Source Analysis Software Use Based Empirical Investigation: (1) Builds quiescent particle background (QPB) spectra and images for observations of extended sources that fill (or mostly fill) the FOV i.e., annular background subtraction won't work. (2) Uses a combination of Filter Wheel Closed (FWC) and corner data to capture the spectral, spatial, and temporal variation of the quiescent particle background. New Work: (1) Improved understanding of the QPB (aided by adding a whole lot of data since 2008). (2) Significantly improved statistics (did I mention a LOT more data?). (3) Better characterization and identification of anomalous states. (4) Builds backgrounds for some anomalous state. (5) New efficient method for non-anomalous states.

  5. Radon Daughters Background Reduction in Alpha Particles Counting System

    International Nuclear Information System (INIS)

    Dadon, S. S.; Pelled, O.; Orion, I.

    2014-01-01

    The ABPC method is using a serially occurring events of the beta decay of the 214Bi fallow by alpha decay of the 214Po that take place almost simultaneously to detect the Pseudo Coincidence Event (PCE) from the RDP, and to subtract them from the gross alpha counts. 267 This work showed that it is possible to improve the efficiency of RDP background reduction, including subtracting the 218Po contribution by using the ABPC method based on a single solid state silicon PIPS detector. False counts percentage obtained at the output of the PCE circuit were smaller than 0.1%. The results show that the PCE circuit was not influenced by non RDP alpha emitters. The PCE system did not reduce the non PCE of the 218Po. After 20 minutes the 218Po was strongly decayed, and its contribution became negligible. In order to overcome this disadvantage, a mathematical matching calculations for the 214Po and the 218Po decay equations were employed, and a constant ratio of the APo214(0) / APo218(0) was obtained. This ratio can be used to estimate the count rate of the 218Po at the first 20 minutes, and to subtract it from the total count rate in order to obtain correct RDP reduction

  6. Comparative study between rib imaging of DR dual energy subtraction technology and chest imaging

    International Nuclear Information System (INIS)

    Yu Jianming; Lei Ziqiao; Kong Xiangchuang

    2006-01-01

    Objective: To investigate the application value of DR dual energy subtraction technology in rib lesions. Methods: 200 patients were performed with chest DR dual energy subtraction, comparing the rib imaging between DR of thorax and chest imaging using ROC analysis. Results: Among the total of 200 patients, there are 50 cases of rib calcification, 7 cases of rib destruction, 22 cases of rib fracture. The calcification, destruction and fracture were displayed respectively by ribs below diaphragm and rib markings. The analytic parameter of rib imaging of DR dual energy subtraction Az is 0.9367, while that of rib imaging of chest Az is 0.6830. Conclusion: DR dual energy subtraction technology is superior to chest imaging in the displaying of rib lesion and ribs below diaphragm. (authors)

  7. Comparison of spatial models for foreground-background segmentation in underwater videos

    OpenAIRE

    Radolko, Martin

    2015-01-01

    The low-level task of foreground-background segregation is an important foundation for many high-level computer vision tasks and has been intensively researched in the past. Nonetheless, unregulated environments usually impose challenging problems, especially the difficult and often neglected underwater environment. There, among others, the edges are blurred, the contrast is impaired and the colors attenuated. Our approach to this problem uses an efficient Background Subtraction algorithm and...

  8. The contribution of chemical shift imaging with digital subtracting images to the diagnosis of steatohepatitis

    International Nuclear Information System (INIS)

    Guo Xinghua; Wang Juanping; Zhang Chongjie; Zheng Guofang; Fan Ruiqiang; Zhu Sumei; Liu Qiwang

    2006-01-01

    Objective: To investigate the diagnosis value of chemical shift imaging with digital subtracting in steatohepatitis. Methods: The in-phase images were subtracted by the out-phase ones in 34 cases of steatohepatitis, and the CNR were measured on these subtracted images to estimate the steatosis of the liver. The relationship of CT grade of steatohepatitis and CNR from the subtracted images was analyzed to evaluate the relationship between CNR and the degree of hepatic steatosis. The sensitivity and specificity of the subtracting and eyeballing methods were compared with chi-square test. Results: On the subtracted images, the liver and spleen were seen nearly the same aspects as low signals, CNR=0.98±0.06, meanwhile the spongy vertebra and the subcutaneous or abdominal lipid were seen as obvious higher signals in 52 normal cases. On the 34 steatohepatitis, scattered high signals were seen in the liver, which made the signal of liver higher than that of spleen, CNR=3.25±0.91--14.35±6.10. There was positive correlation between CNR and CT grade in the 34 cases of steatohepatitis, r=0.893, P<0.01. The sensitivity and specificity of the subtracting method were 88.24% and 94. 23%, significantly higher than that of the eyeballing results, 32.35% and 80.77%, P<0.01 and P<0.05. Conclusion: Chemical shift imaging with digital subtracting is a sensitive, specific, objective method to diagnose steatohepatitis and it is of potential ability for quantitative diagnosis. (authors)

  9. A temporal subtraction method for thoracic CT images based on generalized gradient vector flow

    International Nuclear Information System (INIS)

    Miyake, Noriaki; Kim, H.; Maeda, Shinya; Itai, Yoshinori; Tan, J.K.; Ishikawa, Seiji; Katsuragawa, Shigehiko

    2010-01-01

    A temporal subtraction image, which is obtained by subtraction of a previous image from a current one, can be used for enhancing interval changes (such as formation of new lesions and changes in existing abnormalities) on medical images by removing most of the normal structures. If image registration is incorrect, not only the interval changes but also the normal structures would be appeared as some artifacts on the temporal subtraction image. In a temporal subtraction technique for 2-D X-ray image, the effectiveness is shown through a lot of clinical evaluation experiments, and practical use is advancing. Moreover, the MDCT (Multi-Detector row Computed Tomography) can easily introduced on medical field, the development of a temporal subtraction for thoracic CT Images is expected. In our study, a temporal subtraction technique for thoracic CT Images is developed. As the technique, the vector fields are described by use of GGVF (Generalized Gradient Vector Flow) from the previous and current CT images. Afterwards, VOI (Volume of Interest) are set up on the previous and current CT image pairs. The shift vectors are calculated by using nearest neighbor matching of the vector fields in these VOIs. The search kernel on previous CT image is set up from the obtained shift vector. The previous CT voxel which resemble standard the current voxel is detected by voxel value and vector of the GGVF in the kernel. And, the previous CT image is transformed to the same coordinate of standard voxel. Finally, temporal subtraction image is made by subtraction of a warping image from a current one. To verify the proposal method, the result of application to 7 cases and the effectiveness are described. (author)

  10. Subtractions in the Adler sum rule and violation of charge symmetry

    International Nuclear Information System (INIS)

    Dominguez, C.A.; Moreno, H.; Zepeda, A.

    1976-01-01

    The consequences of a once-subtracted dispersion relation in the derivation of the Adler sum rule are investigated. It is shown that one can expect a breakdown of charge symmetry, of the isotriplet-current hypothesis, and of scaling of the structure functions. These breakdowns are related to the possible presence of a nonzero subtraction function at asymptotic energies and arbitrary q 2 . We also comment about second-class currents and PCAC (partial conservation of axial-vector current) relations

  11. On the usefulness of portal monitor unit subtraction in radiation therapy

    International Nuclear Information System (INIS)

    Kuperman, Vadim Y; Lubich, Leslie M

    2003-01-01

    In order to avoid additional dose to patients caused by portal imaging with megavoltage x-rays, portal monitor units (MUs) are frequently subtracted from the actual treatment MUs. This study examines the usefulness of portal MU subtraction in radiation therapy. For 11 prostate cancer patients treated with 23 MV photons, dose to prostate due to portal filming with 6 MV photons was determined. In all 11 patients subtraction of portal MU values from the actual treatment MUs resulted in a small underdosing of the prostate with an average treatment error of -0.5%. Portal filming without MU subtraction would cause small overdosing of the prostate with an average treatment error of 1.2%. The results of this study indicate that the benefits of portal MU subtraction are in doubt if (a) the energy of treatment x-rays is much higher than that of the portal x-rays and/or (b) when radiotherapy is performed with physical wedges. Based on the obtained results, we argue against unconditional use of the portal MU subtraction method to eliminate the dose from portal imaging

  12. Value of blood-pool subtraction in cardiac indium-111-labeled platelet imaging

    Energy Technology Data Exchange (ETDEWEB)

    Machac, J.; Vallabhajosula, S.; Goldman, M.E.; Goldsmith, S.J.; Palestro, C.; Strashun, A.; Vaquer, R.; Phillips, R.A.; Fuster, V. (Mt. Sinai Medical Center, New York, NY (USA))

    1989-09-01

    Blood-pool subtraction has been proposed to enhance {sup 111}In-labeled platelet imaging of intracardiac thrombi. We tested the accuracy of labeled platelet imaging, with and without blood-pool subtraction, in ten subjects with cardiac thrombi of varying age, eight with endocarditis being treated with antimicrobial therapy and ten normal controls. Imaging was performed early after labeled platelet injection (24 hr or less) and late (48 hr or more). Blood-pool subtraction was carried out. All images were graded subjectively by four experienced, blinded readers. Detection accuracy was measured by the sensitivity at three fixed levels of specificity estimated from receiver operator characteristic curve analysis and tested by three-way analysis of variance. Detection accuracy was generally improved on delayed images. Blood-pool subtraction did not improve accuracy. Although blood-pool subtraction increased detection sensitivity, this was offset by decreased specificity. For this population studied, blood-pool subtraction did not improve subjective detection of abnormal platelet deposition by 111In platelet imaging.

  13. Value of blood-pool subtraction in cardiac indium-111-labeled platelet imaging

    International Nuclear Information System (INIS)

    Machac, J.; Vallabhajosula, S.; Goldman, M.E.; Goldsmith, S.J.; Palestro, C.; Strashun, A.; Vaquer, R.; Phillips, R.A.; Fuster, V.

    1989-01-01

    Blood-pool subtraction has been proposed to enhance 111 In-labeled platelet imaging of intracardiac thrombi. We tested the accuracy of labeled platelet imaging, with and without blood-pool subtraction, in ten subjects with cardiac thrombi of varying age, eight with endocarditis being treated with antimicrobial therapy and ten normal controls. Imaging was performed early after labeled platelet injection (24 hr or less) and late (48 hr or more). Blood-pool subtraction was carried out. All images were graded subjectively by four experienced, blinded readers. Detection accuracy was measured by the sensitivity at three fixed levels of specificity estimated from receiver operator characteristic curve analysis and tested by three-way analysis of variance. Detection accuracy was generally improved on delayed images. Blood-pool subtraction did not improve accuracy. Although blood-pool subtraction increased detection sensitivity, this was offset by decreased specificity. For this population studied, blood-pool subtraction did not improve subjective detection of abnormal platelet deposition by 111In platelet imaging

  14. Thallium-201 and technetium-99m pertechnetate subtraction scintigraphy in patients with hyperparathyroidism

    International Nuclear Information System (INIS)

    Kuwashima, Shigeko; Koizumi, Mitsuru; Goto, Masafumi; Nomura, Toshiharu; Fujioka, Mutsuhisa; Watari, Tsutomu

    1992-01-01

    A reliable technique for detecting and localizing abnormal parathyroid tissue has been a persistent problem. We evaluated thallium-technetium (Tl/Tc) subtraction scintigraphy in 16 patients with clinical biochemical evidence of hyperparathyroidism prior to other diagnostic methods and surgery. Seven patients had surgery and were confirmed to have parathyroid adenoma or hyperplasia. The other methods included ultrasonography (US) in 6 patients, computed tomography (CT) in 10 patients, magnetic resonance imaging (MRI) in 8 patients, and bone scintigraphy in 7 patients. In patients who had several imaging modalities, the detection rate was significantly better for Tl/Tc subtraction scan than for US, CT or MRI. Bote scintigraphy, though not so sensitive as Tl/Tc subtraction studies, was an important tool for evaluating metabolic bone disorder including hyperparathyroidism and renal osteodystrophy. Thus, Tl/Tc subtraction scan is more useful for diagnosis when hyperparathyroidism is suspected if both Tl/Tc subtraction scan and bone scan are performed. The detectability depended on the mass size, and detection of abnormal glands was greater for adenoma than for hyperplasia. The results suggest that Tl/Tc subtraction scan is a simple, non-invasive and useful tool for locating parathyroid abnormality even when compared with MRI. (author)

  15. Pedicle subtraction osteotomy in elderly patients with degenerative sagittal imbalance.

    Science.gov (United States)

    Cho, Kyu-Jung; Kim, Ki-Tack; Kim, Whoan-Jeang; Lee, Sang-Hoon; Jung, Jae-Hoon; Kim, Young-Tae; Park, Hae-Bong

    2013-11-15

    Retrospective, radiographical analysis. To evaluate pedicle subtraction osteotomy (PSO) as a means of correcting severe degenerative sagittal imbalance in elderly patients. PSO in patients with degenerative sagittal imbalance is likely to cause more complications than in patients with iatrogenic flatback deformity. This study analyzed 34 patients who underwent fusion to the sacrum, with a minimum 2-year follow-up. Age of the patients were in the range from 58 to 73 with the mean at 65.5 years. PSO was performed at one segment in all cases, consisting of L3 (n = 26), L4 (n = 4), L2 (n = 3), and L1 (n = 1). The average number of levels fused was 8.15. Ten patients had structural interbody fusion at the lumbosacral junction. Applying PSO at one segment, the mean correction of the lordotic angle at the osteotomy site was 33.3°, of which the loss of correction (LOC) was 4.0° at the last visit. The correction of lumbar lordosis was 33.7° and the LOC was 8.5°. The sagittal C7 plumb was 215.9 mm before surgery, corrected to 35.1 mm after surgery, and changed to 95.9 mm by the last visit. The correction of the sagittal C7 plumb was 119.9 mm and the LOC was 60.9 mm. There was substantial LOC in lumbar lordosis and sagittal C7 plumb. In 10 patients with addition of posterior lumbar interbody fusion, the LOC of lumbar lordosis was 7.4°, which was less than 9° in those without it. PSO for the correction of degenerative sagittal imbalance in elderly patients resulted in correction of sagittal alignment with a significant LOC of lumbar lordosis and sagittal C7 plumb. The LOC of lumbar lordosis occurred at both the osteotomy and non-osteotomy site. The addition of anterior column support is helpful to maintain correction and reduce complications. N/A.

  16. Optimal background matching camouflage.

    Science.gov (United States)

    Michalis, Constantine; Scott-Samuel, Nicholas E; Gibson, David P; Cuthill, Innes C

    2017-07-12

    Background matching is the most familiar and widespread camouflage strategy: avoiding detection by having a similar colour and pattern to the background. Optimizing background matching is straightforward in a homogeneous environment, or when the habitat has very distinct sub-types and there is divergent selection leading to polymorphism. However, most backgrounds have continuous variation in colour and texture, so what is the best solution? Not all samples of the background are likely to be equally inconspicuous, and laboratory experiments on birds and humans support this view. Theory suggests that the most probable background sample (in the statistical sense), at the size of the prey, would, on average, be the most cryptic. We present an analysis, based on realistic assumptions about low-level vision, that estimates the distribution of background colours and visual textures, and predicts the best camouflage. We present data from a field experiment that tests and supports our predictions, using artificial moth-like targets under bird predation. Additionally, we present analogous data for humans, under tightly controlled viewing conditions, searching for targets on a computer screen. These data show that, in the absence of predator learning, the best single camouflage pattern for heterogeneous backgrounds is the most probable sample. © 2017 The Authors.

  17. Robust efficient video fingerprinting

    Science.gov (United States)

    Puri, Manika; Lubin, Jeffrey

    2009-02-01

    We have developed a video fingerprinting system with robustness and efficiency as the primary and secondary design criteria. In extensive testing, the system has shown robustness to cropping, letter-boxing, sub-titling, blur, drastic compression, frame rate changes, size changes and color changes, as well as to the geometric distortions often associated with camcorder capture in cinema settings. Efficiency is afforded by a novel two-stage detection process in which a fast matching process first computes a number of likely candidates, which are then passed to a second slower process that computes the overall best match with minimal false alarm probability. One key component of the algorithm is a maximally stable volume computation - a three-dimensional generalization of maximally stable extremal regions - that provides a content-centric coordinate system for subsequent hash function computation, independent of any affine transformation or extensive cropping. Other key features include an efficient bin-based polling strategy for initial candidate selection, and a final SIFT feature-based computation for final verification. We describe the algorithm and its performance, and then discuss additional modifications that can provide further improvement to efficiency and accuracy.

  18. Background compensation methodologies for contamination monitoring systems

    International Nuclear Information System (INIS)

    Raman, Anand; Chaudhury, Probal; Pradeepkumar, K.S.

    2014-01-01

    Radiation surveillance program in the various nuclear facilities incorporate contamination monitoring as an important component. Contamination monitoring programs constitute monitoring for alpha and beta contamination of the physical entities associated with the working personnel that include his hands, feet, clothing, shoes as well as the general surface areas in the working environment like floors. All these measurements are fraught with the contribution of the ambient gamma background radiation fields. These inhibit a proper and precise estimation of the contamination concentration being monitored. This paper investigates the efficacy of two methodologies that have been incorporated in two of the contamination monitoring systems developed in the Division. In the first system discussed, a high degree of gamma compensation has been achieved for an uniform exposure of the order of 50 nSv/hr to 100 mSv/hr. In the second system discussed, the degree of gamma compensation achieved is equal to those dictated by the statistical nature of the uncertainties associated with the subtraction of background from the source data. These two methods can be very effectively employed depending on the application requirement. A minimum detection level equivalent to 0.37 Bq/cdm 2 has been achieved in both these cases

  19. Digging Deeper: Observing Primordial Gravitational Waves below the Binary-Black-Hole-Produced Stochastic Background.

    Science.gov (United States)

    Regimbau, T; Evans, M; Christensen, N; Katsavounidis, E; Sathyaprakash, B; Vitale, S

    2017-04-14

    The merger rate of black hole binaries inferred from the detections in the first Advanced LIGO science run implies that a stochastic background produced by a cosmological population of mergers will likely mask the primordial gravitational wave background. Here we demonstrate that the next generation of ground-based detectors, such as the Einstein Telescope and Cosmic Explorer, will be able to observe binary black hole mergers throughout the Universe with sufficient efficiency that the confusion background can potentially be subtracted to observe the primordial background at the level of Ω_{GW}≃10^{-13} after 5 years of observation.

  20. Robust automated knowledge capture.

    Energy Technology Data Exchange (ETDEWEB)

    Stevens-Adams, Susan Marie; Abbott, Robert G.; Forsythe, James Chris; Trumbo, Michael Christopher Stefan; Haass, Michael Joseph; Hendrickson, Stacey M. Langfitt

    2011-10-01

    This report summarizes research conducted through the Sandia National Laboratories Robust Automated Knowledge Capture Laboratory Directed Research and Development project. The objective of this project was to advance scientific understanding of the influence of individual cognitive attributes on decision making. The project has developed a quantitative model known as RumRunner that has proven effective in predicting the propensity of an individual to shift strategies on the basis of task and experience related parameters. Three separate studies are described which have validated the basic RumRunner model. This work provides a basis for better understanding human decision making in high consequent national security applications, and in particular, the individual characteristics that underlie adaptive thinking.

  1. Passion, Robustness and Perseverance

    DEFF Research Database (Denmark)

    Lim, Miguel Antonio; Lund, Rebecca

    2016-01-01

    Evaluation and merit in the measured university are increasingly based on taken-for-granted assumptions about the “ideal academic”. We suggest that the scholar now needs to show that she is passionate about her work and that she gains pleasure from pursuing her craft. We suggest that passion...... and pleasure achieve an exalted status as something compulsory. The scholar ought to feel passionate about her work and signal that she takes pleasure also in the difficult moments. Passion has become a signal of robustness and perseverance in a job market characterised by funding shortages, increased pressure...... way to demonstrate their potential and, crucially, their passion for their work. Drawing on the literature on technologies of governance, we reflect on what is captured and what is left out by these two evaluation instruments. We suggest that bibliometric analysis at the individual level is deeply...

  2. Robust Optical Flow Estimation

    Directory of Open Access Journals (Sweden)

    Javier Sánchez Pérez

    2013-10-01

    Full Text Available n this work, we describe an implementation of the variational method proposed by Brox etal. in 2004, which yields accurate optical flows with low running times. It has several benefitswith respect to the method of Horn and Schunck: it is more robust to the presence of outliers,produces piecewise-smooth flow fields and can cope with constant brightness changes. Thismethod relies on the brightness and gradient constancy assumptions, using the information ofthe image intensities and the image gradients to find correspondences. It also generalizes theuse of continuous L1 functionals, which help mitigate the effect of outliers and create a TotalVariation (TV regularization. Additionally, it introduces a simple temporal regularizationscheme that enforces a continuous temporal coherence of the flow fields.

  3. Robust Multimodal Dictionary Learning

    Science.gov (United States)

    Cao, Tian; Jojic, Vladimir; Modla, Shannon; Powell, Debbie; Czymmek, Kirk; Niethammer, Marc

    2014-01-01

    We propose a robust multimodal dictionary learning method for multimodal images. Joint dictionary learning for both modalities may be impaired by lack of correspondence between image modalities in training data, for example due to areas of low quality in one of the modalities. Dictionaries learned with such non-corresponding data will induce uncertainty about image representation. In this paper, we propose a probabilistic model that accounts for image areas that are poorly corresponding between the image modalities. We cast the problem of learning a dictionary in presence of problematic image patches as a likelihood maximization problem and solve it with a variant of the EM algorithm. Our algorithm iterates identification of poorly corresponding patches and re-finements of the dictionary. We tested our method on synthetic and real data. We show improvements in image prediction quality and alignment accuracy when using the method for multimodal image registration. PMID:24505674

  4. Robust snapshot interferometric spectropolarimetry.

    Science.gov (United States)

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

    2016-05-15

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

  5. International Conference on Robust Statistics

    CERN Document Server

    Filzmoser, Peter; Gather, Ursula; Rousseeuw, Peter

    2003-01-01

    Aspects of Robust Statistics are important in many areas. Based on the International Conference on Robust Statistics 2001 (ICORS 2001) in Vorau, Austria, this volume discusses future directions of the discipline, bringing together leading scientists, experienced researchers and practitioners, as well as younger researchers. The papers cover a multitude of different aspects of Robust Statistics. For instance, the fundamental problem of data summary (weights of evidence) is considered and its robustness properties are studied. Further theoretical subjects include e.g.: robust methods for skewness, time series, longitudinal data, multivariate methods, and tests. Some papers deal with computational aspects and algorithms. Finally, the aspects of application and programming tools complete the volume.

  6. Cosmic microwave background radiation

    International Nuclear Information System (INIS)

    Wilson, R.W.

    1979-01-01

    The 20-ft horn-reflector antenna at Bell Laboratories is discussed in detail with emphasis on the 7.35 cm radiometer. The circumstances leading to the detection of the cosmic microwave background radiation are explored

  7. Robustness Analyses of Timber Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard; Hald, Frederik

    2013-01-01

    The robustness of structural systems has obtained a renewed interest arising from a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. In order to minimise the likelihood of such disproportionate structural failures, many mo...... with respect to robustness of timber structures and will discuss the consequences of such robustness issues related to the future development of timber structures.......The robustness of structural systems has obtained a renewed interest arising from a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. In order to minimise the likelihood of such disproportionate structural failures, many...... modern building codes consider the need for the robustness of structures and provide strategies and methods to obtain robustness. Therefore, a structural engineer may take necessary steps to design robust structures that are insensitive to accidental circumstances. The present paper summaries issues...

  8. Zambia Country Background Report

    DEFF Research Database (Denmark)

    Hampwaye, Godfrey; Jeppesen, Søren; Kragelund, Peter

    This paper provides background data and general information for the Zambia studies focusing on local food processing sub­‐sector; and the local suppliers to the mines as part of the SAFIC project (Successful African Firms and Institutional Change).......This paper provides background data and general information for the Zambia studies focusing on local food processing sub­‐sector; and the local suppliers to the mines as part of the SAFIC project (Successful African Firms and Institutional Change)....

  9. Informed baseline subtraction of proteomic mass spectrometry data aided by a novel sliding window algorithm.

    Science.gov (United States)

    Stanford, Tyman E; Bagley, Christopher J; Solomon, Patty J

    2016-01-01

    Proteomic matrix-assisted laser desorption/ionisation (MALDI) linear time-of-flight (TOF) mass spectrometry (MS) may be used to produce protein profiles from biological samples with the aim of discovering biomarkers for disease. However, the raw protein profiles suffer from several sources of bias or systematic variation which need to be removed via pre-processing before meaningful downstream analysis of the data can be undertaken. Baseline subtraction, an early pre-processing step that removes the non-peptide signal from the spectra, is complicated by the following: (i) each spectrum has, on average, wider peaks for peptides with higher mass-to-charge ratios ( m / z ), and (ii) the time-consuming and error-prone trial-and-error process for optimising the baseline subtraction input arguments. With reference to the aforementioned complications, we present an automated pipeline that includes (i) a novel 'continuous' line segment algorithm that efficiently operates over data with a transformed m / z -axis to remove the relationship between peptide mass and peak width, and (ii) an input-free algorithm to estimate peak widths on the transformed m / z scale. The automated baseline subtraction method was deployed on six publicly available proteomic MS datasets using six different m/z-axis transformations. Optimality of the automated baseline subtraction pipeline was assessed quantitatively using the mean absolute scaled error (MASE) when compared to a gold-standard baseline subtracted signal. Several of the transformations investigated were able to reduce, if not entirely remove, the peak width and peak location relationship resulting in near-optimal baseline subtraction using the automated pipeline. The proposed novel 'continuous' line segment algorithm is shown to far outperform naive sliding window algorithms with regard to the computational time required. The improvement in computational time was at least four-fold on real MALDI TOF-MS data and at least an order of

  10. Removal of arterial wall calcifications in CT angiography by local subtraction

    International Nuclear Information System (INIS)

    Straten, Marcel van; Venema, Henk W.; Streekstra, Geert J.; Reekers, Jim A.; Heeten, Gerard J. den; Grimbergen, Cornelis A.

    2003-01-01

    CT Angiography (CTA) is an established technique for the minimally invasive imaging of arteries. The technique of maximum intensity projection (MIP) is often used to get a comprehensive overview of the vascular anatomy. On a MIP, however, arterial wall calcifications may hinder the visualization of the arterial lumen. These calcifications are in direct contact with the contrast-enhanced blood, which makes removal difficult. We present a local subtraction method for the automatic removal of these calcifications. In our approach a second CT scan has to be made, prior to contrast injection. The calcifications in both scans are registered prior to subtraction to compensate for displacements in between the two scans. Local subtraction results are compared with results obtained by thresholding. The method was tested in a phantom and with data from four patients. The phantom represented an artery with different types of stenosis. Data were used from patients for which CTA of the renal arteries was performed. For two patients the electrocardiogram (ECG) was recorded during the CTA examination, making retrospective cardiac gated reconstructions possible. Both the phantom and the patient study showed that the local subtraction method is capable of removing calcifications and visualizing the residual lumen. In the patient study it appeared that some artifacts remained for higher pitch values. We conclude that the local subtraction method is less subjective and more accurate than thresholding. Best results are obtained by use of a small pitch, at the expense of the volume covered during a single breath hold

  11. Bone images from dual-energy subtraction chest radiography in the detection of rib fractures.

    Science.gov (United States)

    Szucs-Farkas, Zsolt; Lautenschlager, Katrin; Flach, Patricia M; Ott, Daniel; Strautz, Tamara; Vock, Peter; Ruder, Thomas D

    2011-08-01

    To assess the sensitivity and image quality of chest radiography (CXR) with or without dual-energy subtracted (ES) bone images in the detection of rib fractures. In this retrospective study, 39 patients with 204 rib fractures and 24 subjects with no fractures were examined with a single exposure dual-energy subtraction digital radiography system. Three blinded readers first evaluated the non-subtracted posteroanterior and lateral chest radiographs alone, and 3 months later they evaluated the non-subtracted images together with the subtracted posteroanterior bone images. The locations of rib fractures were registered with confidence levels on a 3-grade scale. Image quality was rated on a 5-point scale. Marks by readers were compared with fracture localizations in CT as a standard of reference. The sensivity for fracture detection using both methods was very similar (34.3% with standard CXR and 33.5% with ES-CXR, p=0.92). At the patient level, both sensitivity (71.8%) and specificity (92.9%) with or without ES were identical. Diagnostic confidence was not significantly different (2.61 with CXR and 2.75 with ES-CXR, p=0.063). Image quality with ES was rated higher than that on standard CXR (4.08 vs. 3.74, prib fractures. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  12. Digital image comparison by subtracting contextual transformations—percentile rank order differentiation

    Science.gov (United States)

    Wehde, M. E.

    1995-01-01

    The common method of digital image comparison by subtraction imposes various constraints on the image contents. Precise registration of images is required to assure proper evaluation of surface locations. The attribute being measured and the calibration and scaling of the sensor are also important to the validity and interpretability of the subtraction result. Influences of sensor gains and offsets complicate the subtraction process. The presence of any uniform systematic transformation component in one of two images to be compared distorts the subtraction results and requires analyst intervention to interpret or remove it. A new technique has been developed to overcome these constraints. Images to be compared are first transformed using the cumulative relative frequency as a transfer function. The transformed images represent the contextual relationship of each surface location with respect to all others within the image. The process of differentiating between the transformed images results in a percentile rank ordered difference. This process produces consistent terrain-change information even when the above requirements necessary for subtraction are relaxed. This technique may be valuable to an appropriately designed hierarchical terrain-monitoring methodology because it does not require human participation in the process.

  13. Robust and Adaptive Control With Aerospace Applications

    CERN Document Server

    Lavretsky, Eugene

    2013-01-01

    Robust and Adaptive Control shows the reader how to produce consistent and accurate controllers that operate in the presence of uncertainties and unforeseen events. Driven by aerospace applications the focus of the book is primarily on continuous-dynamical systems.  The text is a three-part treatment, beginning with robust and optimal linear control methods and moving on to a self-contained presentation of the design and analysis of model reference adaptive control (MRAC) for nonlinear uncertain dynamical systems. Recent extensions and modifications to MRAC design are included, as are guidelines for combining robust optimal and MRAC controllers. Features of the text include: ·         case studies that demonstrate the benefits of robust and adaptive control for piloted, autonomous and experimental aerial platforms; ·         detailed background material for each chapter to motivate theoretical developments; ·         realistic examples and simulation data illustrating key features ...

  14. Incremental principal component pursuit for video background modeling

    Science.gov (United States)

    Rodriquez-Valderrama, Paul A.; Wohlberg, Brendt

    2017-03-14

    An incremental Principal Component Pursuit (PCP) algorithm for video background modeling that is able to process one frame at a time while adapting to changes in background, with a computational complexity that allows for real-time processing, having a low memory footprint and is robust to translational and rotational jitter.

  15. Dynamics robustness of cascading systems.

    Directory of Open Access Journals (Sweden)

    Jonathan T Young

    2017-03-01

    Full Text Available A most important property of biochemical systems is robustness. Static robustness, e.g., homeostasis, is the insensitivity of a state against perturbations, whereas dynamics robustness, e.g., homeorhesis, is the insensitivity of a dynamic process. In contrast to the extensively studied static robustness, dynamics robustness, i.e., how a system creates an invariant temporal profile against perturbations, is little explored despite transient dynamics being crucial for cellular fates and are reported to be robust experimentally. For example, the duration of a stimulus elicits different phenotypic responses, and signaling networks process and encode temporal information. Hence, robustness in time courses will be necessary for functional biochemical networks. Based on dynamical systems theory, we uncovered a general mechanism to achieve dynamics robustness. Using a three-stage linear signaling cascade as an example, we found that the temporal profiles and response duration post-stimulus is robust to perturbations against certain parameters. Then analyzing the linearized model, we elucidated the criteria of when signaling cascades will display dynamics robustness. We found that changes in the upstream modules are masked in the cascade, and that the response duration is mainly controlled by the rate-limiting module and organization of the cascade's kinetics. Specifically, we found two necessary conditions for dynamics robustness in signaling cascades: 1 Constraint on the rate-limiting process: The phosphatase activity in the perturbed module is not the slowest. 2 Constraints on the initial conditions: The kinase activity needs to be fast enough such that each module is saturated even with fast phosphatase activity and upstream changes are attenuated. We discussed the relevance of such robustness to several biological examples and the validity of the above conditions therein. Given the applicability of dynamics robustness to a variety of systems, it

  16. Identification of differentially expressed genes in SHSY5Y cells exposed to okadaic acid by suppression subtractive hybridization

    Directory of Open Access Journals (Sweden)

    Valdiglesias Vanessa

    2012-01-01

    Full Text Available Abstract Background Okadaic acid (OA, a toxin produced by several dinoflagellate species is responsible for frequent food poisonings associated to shellfish consumption. Although several studies have documented the OA effects on different processes such as cell transformation, apoptosis, DNA repair or embryogenesis, the molecular mechanistic basis for these and other effects is not completely understood and the number of controversial data on OA is increasing in the literature. Results In this study, we used suppression subtractive hybridization in SHSY5Y cells to identify genes that are differentially expressed after OA exposure for different times (3, 24 and 48 h. A total of 247 subtracted clones which shared high homology with known genes were isolated. Among these, 5 specific genes associated with cytoskeleton and neurotransmission processes (NEFM, TUBB, SEPT7, SYT4 and NPY were selected to confirm their expression levels by real-time PCR. Significant down-regulation of these genes was obtained at the short term (3 and 24 h OA exposure, excepting for NEFM, but their expression was similar to the controls at 48 h. Conclusions From all the obtained genes, 114 genes were up-regulated and 133 were down-regulated. Based on the NCBI GenBank and Gene Ontology databases, most of these genes are involved in relevant cell functions such as metabolism, transport, translation, signal transduction and cell cycle. After quantitative PCR analysis, the observed underexpression of the selected genes could underlie the previously reported OA-induced cytoskeleton disruption, neurotransmission alterations and in vivo neurotoxic effects. The basal expression levels obtained at 48 h suggested that surviving cells were able to recover from OA-caused gene expression alterations.

  17. Robust continuous clustering.

    Science.gov (United States)

    Shah, Sohil Atul; Koltun, Vladlen

    2017-09-12

    Clustering is a fundamental procedure in the analysis of scientific data. It is used ubiquitously across the sciences. Despite decades of research, existing clustering algorithms have limited effectiveness in high dimensions and often require tuning parameters for different domains and datasets. We present a clustering algorithm that achieves high accuracy across multiple domains and scales efficiently to high dimensions and large datasets. The presented algorithm optimizes a smooth continuous objective, which is based on robust statistics and allows heavily mixed clusters to be untangled. The continuous nature of the objective also allows clustering to be integrated as a module in end-to-end feature learning pipelines. We demonstrate this by extending the algorithm to perform joint clustering and dimensionality reduction by efficiently optimizing a continuous global objective. The presented approach is evaluated on large datasets of faces, hand-written digits, objects, newswire articles, sensor readings from the Space Shuttle, and protein expression levels. Our method achieves high accuracy across all datasets, outperforming the best prior algorithm by a factor of 3 in average rank.

  18. The natural radiation background

    International Nuclear Information System (INIS)

    Duggleby, J.C.

    1982-01-01

    The components of the natural background radiation and their variations are described. Cosmic radiation is a major contributor to the external dose to the human body whilst naturally-occurring radionuclides of primordial and cosmogenic origin contribute to both the external and internal doses, with the primordial radionuclides being the major contributor in both cases. Man has continually modified the radiation dose to which he has been subjected. The two traditional methods of measuring background radiation, ionisation chamber measurements and scintillation counting, are looked at and the prospect of using thermoluminescent dosimetry is considered

  19. Effects of background radiation

    International Nuclear Information System (INIS)

    Knox, E.G.; Stewart, A.M.; Gilman, E.A.; Kneale, G.W.

    1987-01-01

    The primary objective of this investigation is to measure the relationship between exposure to different levels of background gamma radiation in different parts of the country, and different Relative Risks for leukaemias and cancers in children. The investigation is linked to an earlier analysis of the effects of prenatal medical x-rays upon leukaemia and cancer risk; the prior hypothesis on which the background-study was based, is derived from the earlier results. In a third analysis, the authors attempted to measure varying potency of medical x-rays delivered at different stages of gestation and the results supply a link between the other two estimates. (author)

  20. The cosmic microwave background

    International Nuclear Information System (INIS)

    Silk, J.

    1991-01-01

    Recent limits on spectral distortions and angular anisotropies in the cosmic microwave background are reviewed. The various backgrounds are described, and the theoretical implications are assessed. Constraints on inflationary cosmology dominated by cold dark matter (CDM) and on open cosmological models dominated by baryonic dark matter (BDM), with, respectively, primordial random phase scale-invariant curvature fluctuations or non-gaussian isocurvature fluctuations are described. More exotic theories are addressed, and I conclude with the 'bottom line': what theories expect experimentalists to be measuring within the next two to three years without having to abandon their most cherished theorists. (orig.)

  1. The Cosmic Background Explorer

    Science.gov (United States)

    Gulkis, Samuel; Lubin, Philip M.; Meyer, Stephan S.; Silverberg, Robert F.

    1990-01-01

    The Cosmic Background Explorer (CBE), NASA's cosmological satellite which will observe a radiative relic of the big bang, is discussed. The major questions connected to the big bang theory which may be clarified using the CBE are reviewed. The satellite instruments and experiments are described, including the Differential Microwave Radiometer, which measures the difference between microwave radiation emitted from two points on the sky, the Far-Infrared Absolute Spectrophotometer, which compares the spectrum of radiation from the sky at wavelengths from 100 microns to one cm with that from an internal blackbody, and the Diffuse Infrared Background Experiment, which searches for the radiation from the earliest generation of stars.

  2. Robust Trust in Expert Testimony

    Directory of Open Access Journals (Sweden)

    Christian Dahlman

    2015-05-01

    Full Text Available The standard of proof in criminal trials should require that the evidence presented by the prosecution is robust. This requirement of robustness says that it must be unlikely that additional information would change the probability that the defendant is guilty. Robustness is difficult for a judge to estimate, as it requires the judge to assess the possible effect of information that the he or she does not have. This article is concerned with expert witnesses and proposes a method for reviewing the robustness of expert testimony. According to the proposed method, the robustness of expert testimony is estimated with regard to competence, motivation, external strength, internal strength and relevance. The danger of trusting non-robust expert testimony is illustrated with an analysis of the Thomas Quick Case, a Swedish legal scandal where a patient at a mental institution was wrongfully convicted for eight murders.

  3. [The backgroud sky subtraction around [OIII] line in LAMOST QSO spectra].

    Science.gov (United States)

    Shi, Zhi-Xin; Comte, Georges; Luo, A-Li; Tu, Liang-Ping; Zhao, Yong-Heng; Wu, Fu-Chao

    2014-11-01

    At present, most sky-subtraction methods focus on the full spectrum, not the particular location, especially for the backgroud sky around [OIII] line which is very important to low redshift quasars. A new method to precisely subtract sky lines in local region is proposed in the present paper, which sloves the problem that the width of Hβ-[OIII] line is effected by the backgroud sky subtraction. The exprimental results show that, for different redshift quasars, the spectral quality has been significantly improved using our method relative to the original batch program by LAMOST. It provides a complementary solution for the small part of LAMOST spectra which are not well handled by LAMOST 2D pipeline. Meanwhile, This method has been used in searching for candidates of double-peaked Active Galactic Nuclei.

  4. Dynamic contrast-enhanced subtraction MR angiography in intracranial vascular abnormalities

    International Nuclear Information System (INIS)

    Takano, K.; Ono, H.; Utsunomiya, H.; Okazaki, M.; Tanaka, A.

    1999-01-01

    We present our clinical experience with dynamic contrast-enhanced MR angiography (MRA) with subtraction for assessing intracranial vascular abnormalities. Ten patients with various cerebrovascular disorders underwent dynamic contrast-enhanced MRA on a 1.0-T system. Thirty sections (2 mm) were acquired in 29-30 s. Maximum intensity projection images and subtracted source images were compared with those obtained by conventional angiography. In all cases, the presence or absence of abnormalities in the targeted vessels, as well as the morphology of the sagittal sinuses, was clearly visualized as in conventional angiography, without any obstructions such as hyperintense hematomas or thrombi, or intraluminal turbulence. Although the temporal and spatial resolutions with current hardware are insufficient, these preliminary results suggest that dynamic contrast-enhanced MRA with subtraction may be useful for assessing vascular lesions with hemorrhage or thrombus, and the dural sinuses. (orig.)

  5. Two-dimensional real-time imaging system for subtraction angiography using an iodine filter

    Science.gov (United States)

    Umetani, Keiji; Ueda, Ken; Takeda, Tohoru; Anno, Izumi; Itai, Yuji; Akisada, Masayoshi; Nakajima, Teiichi

    1992-01-01

    A new type of subtraction imaging system was developed using an iodine filter and a single-energy broad bandwidth monochromatized x ray. The x-ray images of coronary arteries made after intravenous injection of a contrast agent are enhanced by an energy-subtraction technique. Filter chopping of the x-ray beam switches energies rapidly, so that a nearly simultaneous pair of filtered and nonfiltered images can be made. By using a high-speed video camera, a pair of two 512 × 512 pixel images can be obtained within 9 ms. Three hundred eighty-four images (raw data) are stored in a 144-Mbyte frame memory. After phantom studies, in vivo subtracted images of coronary arteries in dogs were obtained at a rate of 15 images/s.

  6. Aggression-related brain function assessed with the Point Subtraction Aggression Paradigm in fMRI

    DEFF Research Database (Denmark)

    Skibsted, Anine P; Cunha-Bang, Sofi da; Carré, Justin M

    2017-01-01

    The Point Subtraction Aggression Paradigm (PSAP) measures aggressive behavior in response to provocations. The aim of the study was to implement the PSAP in a functional neuroimaging environment (fMRI) and evaluate aggression-related brain reactivity including response to provocations and associa......The Point Subtraction Aggression Paradigm (PSAP) measures aggressive behavior in response to provocations. The aim of the study was to implement the PSAP in a functional neuroimaging environment (fMRI) and evaluate aggression-related brain reactivity including response to provocations...... and associations with aggression within the paradigm. Twenty healthy participants completed two 12-min PSAP sessions within the scanner. We evaluated brain responses to aggressive behavior (removing points from an opponent), provocations (point subtractions by the opponent), and winning points. Our results showed...... with the involvement of these brain regions in emotional and impulsive behavior. Striatal reactivity may suggest an involvement of reward during winning and stealing points....

  7. Enhancing quantum entanglement for continuous variables by a coherent superposition of photon subtraction and addition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Su-Yong; Kim, Ho-Joon [Department of Physics, Texas A and M University at Qatar, P.O. Box 23874, Doha (Qatar); Ji, Se-Wan [School of Computational Sciences, Korea Institute for Advanced Study, Seoul 130-012 (Korea, Republic of); Nha, Hyunchul [Department of Physics, Texas A and M University at Qatar, P.O. Box 23874, Doha (Qatar); Institute fuer Quantenphysik, Universitaet Ulm, D-89069 Ulm (Germany)

    2011-07-15

    We investigate how the entanglement properties of a two-mode state can be improved by performing a coherent superposition operation ta+ra{sup {dagger}} of photon subtraction and addition, proposed by Lee and Nha [Phys. Rev. A 82, 053812 (2010)], on each mode. We show that the degree of entanglement, the Einstein-Podolsky-Rosen-type correlation, and the performance of quantum teleportation can be all enhanced for the output state when the coherent operation is applied to a two-mode squeezed state. The effects of the coherent operation are more prominent than those of the mere photon subtraction a and the addition a{sup {dagger}} particularly in the small-squeezing regime, whereas the optimal operation becomes the photon subtraction (case of r=0) in the large-squeezing regime.

  8. Spectral Subtraction Approach for Interference Reduction of MIMO Channel Wireless Systems

    Directory of Open Access Journals (Sweden)

    Tomohiro Ono

    2005-08-01

    Full Text Available In this paper, a generalized spectral subtraction approach for reducing additive impulsive noise, narrowband signals, white Gaussian noise and DS-CDMA interferences in MIMO channel DS-CDMA wireless communication systems is investigated. The interference noise reduction or suppression is essential problem in wireless mobile communication systems to improve the quality of communication. The spectrum subtraction scheme is applied to the interference noise reduction problems for noisy MIMO channel systems. The interferences in space and time domain signals can effectively be suppressed by selecting threshold values, and the computational load with the FFT is not large. Further, the fading effects of channel are compensated by spectral modification with the spectral subtraction process. In the simulations, the effectiveness of the proposed methods for the MIMO channel DS-CDMA is shown to compare with the conventional MIMO channel DS-CDMA.

  9. Effect of relative nanohole position on colour purity of ultrathin plasmonic subtractive colour filters

    International Nuclear Information System (INIS)

    Sun, L B; Hu, X L; Zhang, D X; Zeng, Beibei; Wang, L S; Yang, S M; Tai, R Z; Fecht, H J; Jiang, J Z

    2015-01-01

    Plasmonic subtractive color filters through patterning periodic nanostructures on ultrathin Ag films deposited on a glass substrate, exhibiting good durability, simple fabrication, and flexible color tunability, have attracted considerable attention due to their tremendous potential applications. While previous studies have mainly focused on their extraordinary physical mechanisms, color purity, which is another key parameter for high quality imaging applications, has been much less investigated. In this work, we demonstrate that the relative position of nanoholes patterned on ultrathin Ag films can largely affect the color purity of plasmonic subtractive color filters. The calculated results agree reasonably well with the experimental data, revealing that the purity of subtractive colors can be improved by changing the nanohole arrays from square lattice to triangular lattice without reducing transmission at visible frequencies. In addition, underlying mechanisms are clarified by systematically analyzing the dominant valley in transmission spectra. (paper)

  10. A simultaneous all-optical half/full-subtraction strategy using cascaded highly nonlinear fibers

    Science.gov (United States)

    Singh, Karamdeep; Kaur, Gurmeet; Singh, Maninder Lal

    2018-02-01

    Using non-linear effects such as cross-gain modulation (XGM) and cross-phase modulation (XPM) inside two highly non-linear fibres (HNLF) arranged in cascaded configuration, a simultaneous half/full-subtracter is proposed. The proposed simultaneous half/full-subtracter design is attractive due to several features such as input data pattern independence and usage of minimal number of non-linear elements i.e. HNLFs. Proof of concept simulations have been conducted at 100 Gbps rate, indicating fine performance, as extinction ratio (dB) > 6.28 dB and eye opening factors (EO) > 77.1072% are recorded for each implemented output. The proposed simultaneous half/full-subtracter can be used as a key component in all-optical information processing circuits.

  11. Venous digital subtraction angiography for diagnosis of renal artery stenosis in arterial hypertony

    International Nuclear Information System (INIS)

    Schoerner, W.; Kempter, H.; Banzer, D.; Aviles, C.; Weiss, T.; Felix, R.

    1984-01-01

    Venous digital subtraction angiography was performed in 248 patients for the diagnosis of renal arterial stenosis. In 88% of the investigations the stenosis could be found. Comparison of digital angiography and conventional angiography was made for 57 renal arteries (25 investigations). In 52 renal arteries we found the same results with both methods, in 5 renal arteries we found the same results with both methods, in 5 renal arteries the digital angiography showed false positive results. The spatial resolution of digital subtraction angiography is sufficient for the correct diagnosis of significant renal arterial stenosis. With regard to the lower invasion of digital subtraction angiography compared to conventional angiography the first method should be used for clarification of renal arterial hypertension. (orig.)

  12. Continuous-variable measurement-device-independent quantum key distribution with photon subtraction

    Science.gov (United States)

    Ma, Hong-Xin; Huang, Peng; Bai, Dong-Yun; Wang, Shi-Yu; Bao, Wan-Su; Zeng, Gui-Hua

    2018-04-01

    It has been found that non-Gaussian operations can be applied to increase and distill entanglement between Gaussian entangled states. We show the successful use of the non-Gaussian operation, in particular, photon subtraction operation, on the continuous-variable measurement-device-independent quantum key distribution (CV-MDI-QKD) protocol. The proposed method can be implemented based on existing technologies. Security analysis shows that the photon subtraction operation can remarkably increase the maximal transmission distance of the CV-MDI-QKD protocol, which precisely make up for the shortcoming of the original CV-MDI-QKD protocol, and one-photon subtraction operation has the best performance. Moreover, the proposed protocol provides a feasible method for the experimental implementation of the CV-MDI-QKD protocol.

  13. Simultaneous optical digital half-subtraction and -addition using SOAs and a PPLN waveguide.

    Science.gov (United States)

    McGeehan, John E; Kumar, Saurabh; Willner, Alan E

    2007-04-30

    We demonstrate an optical half-subtracter and half-adder module that performs simultaneous bit-wise subtraction and addition of two 5 Gbit/s RZ data streams. We generate Borrow (/X*Y) and Difference/Sum (X plus sign in circleY, or XOR) outputs using cross-gain modulation (XGM) in two parallel SOAs. Taking advantage of the gain saturation inherent to SOAs, we generate two signals, /X*Y, and X*/Y, and combine them using a passive optical coupler to generate the XOR Difference/Sum output. We use difference-frequency-generation-based lambda-conversion in a PPLN waveguide to generate the Carry (X*Y) output. The PPLN waveguide allows bit-synchronous wavelength shifting, is wide-bandwidth, and offers no intrinsic chirp. Our module uses three active elements to perform simultaneous half-subtraction and addition, and carries a maximum power penalty of 1.0 dB.

  14. Clinical application of subtraction CT imaging for evaluation of pulmonary vascular permeability

    International Nuclear Information System (INIS)

    Kato, Shiro; Asai, Toshihiko; Yatagai, Shigeo; Oonuma, Noboru; Ohno, Kunihiko; Nakamoto, Takaaki; Iizuka, Masahiko

    1991-01-01

    In this clinical study, one normal subject, one patient with primary interstitial pneumonia, one patient with segmental pneumonia due to Staphylococcus aureus, one patient with post-operative esophageal carcinoma, and two patients with mitral stenosis were studied. Dynamic CT scan images under continuous injection of low osmotic contrast medium were analyzed in series, in an attempt to evaluate vascular permeability quantitatively. The following results were obtained. Subtraction CT scan image 10 minutes after the start of contrast medium injection in two patients with pneumonia, showed a reduction of pulmonary vascular permeability following therapy. Subtraction CT scan image of the patient with post-operative esophageal carcinoma treated with 25 Gy radiation showed a discrepancy between pulmonary vascular permeability and other findings. In hemodynamically stable patients with mitral stenosis, subtraction CT images demonstrated that pulmonary vascular permeability was not affected by pulmonary congestion, irrespective of its severity. (author)

  15. Contrast-enhanced MR angiography vs intra-arterial digital subtraction angiography for carotid imaging: activity-based cost analysis

    International Nuclear Information System (INIS)

    U-King-Im, Jean Marie; Cross, Justin J.; Higgins, Nicholas J.; Graves, Martin J.; Antoun, Nagui M.; Gillard, Jonathan H.; Hollingworth, William; Trivedi, Rikin A.; Kirkpatrick, Peter J.

    2004-01-01

    The aim of this study was to compare the costs of performing contrast-enhanced MR angiography (CE MRA) with intra-arterial digital subtraction angiography (DSA) for the evaluation of carotid atherosclerotic disease. Activity-based cost analysis was used to identify the costs of performing each procedure. The variable direct costs of performing CE MRA and DSA were determined in 20 patients by using detailed time and motion studies. All personnel directly involved in the cases were tracked to the nearest minute and all consumable items used were recorded. Moreover, procedure times were prospectively recorded for an additional 80 patients who underwent both DSA and CE MRA. The variable direct costs of bed usage in the angiography day-case unit, all direct fixed costs as well as indirect costs were assessed from hospital and departmental accounting records. Total costs for each procedure were calculated and compared using Wilcoxon signed-rank sum test. Mean aggregate costs were and euro;721 for DSA and and euro;306 for CE MRA, resulting in potential savings of and euro;415 per patient (p<0.0001). On average, a DSA procedure thus cost approximately 2.4 (95% confidence intervals: 2.2-2.6) times more than CE MRA to our medical institution. Sensitivity analyses confirmed the robustness of our conclusions across wide ranges of plausible values for various parameters. Assuming equal diagnostic performance, institutions may have substantial cost savings if CE MRA is used instead of DSA for carotid imaging. (orig.)

  16. Contrast-enhanced MR angiography vs intra-arterial digital subtraction angiography for carotid imaging: activity-based cost analysis

    Energy Technology Data Exchange (ETDEWEB)

    U-King-Im, Jean Marie; Cross, Justin J.; Higgins, Nicholas J.; Graves, Martin J.; Antoun, Nagui M.; Gillard, Jonathan H. [University Department of Radiology, Addenbrooke' s Hospital, CB2 2QQ, Cambridge (United Kingdom); Hollingworth, William [Department of Radiology, University of Washington, WA 98103, Seattle (United States); Trivedi, Rikin A. [University Department of Radiology, Addenbrooke' s Hospital, CB2 2QQ, Cambridge (United Kingdom); Academic Department of Neurosurgery, Addenbrooke' s Hospital, CB2 2QQ, Cambridge (United Kingdom); Kirkpatrick, Peter J. [Academic Department of Neurosurgery, Addenbrooke' s Hospital, CB2 2QQ, Cambridge (United Kingdom)

    2004-04-01

    The aim of this study was to compare the costs of performing contrast-enhanced MR angiography (CE MRA) with intra-arterial digital subtraction angiography (DSA) for the evaluation of carotid atherosclerotic disease. Activity-based cost analysis was used to identify the costs of performing each procedure. The variable direct costs of performing CE MRA and DSA were determined in 20 patients by using detailed time and motion studies. All personnel directly involved in the cases were tracked to the nearest minute and all consumable items used were recorded. Moreover, procedure times were prospectively recorded for an additional 80 patients who underwent both DSA and CE MRA. The variable direct costs of bed usage in the angiography day-case unit, all direct fixed costs as well as indirect costs were assessed from hospital and departmental accounting records. Total costs for each procedure were calculated and compared using Wilcoxon signed-rank sum test. Mean aggregate costs were and euro;721 for DSA and and euro;306 for CE MRA, resulting in potential savings of and euro;415 per patient (p<0.0001). On average, a DSA procedure thus cost approximately 2.4 (95% confidence intervals: 2.2-2.6) times more than CE MRA to our medical institution. Sensitivity analyses confirmed the robustness of our conclusions across wide ranges of plausible values for various parameters. Assuming equal diagnostic performance, institutions may have substantial cost savings if CE MRA is used instead of DSA for carotid imaging. (orig.)

  17. Evaluation of the minimum iodine concentration for contrast-enhanced subtraction mammography

    International Nuclear Information System (INIS)

    Baldelli, P; Bravin, A; Maggio, C Di; Gennaro, G; Sarnelli, A; Taibi, A; Gambaccini, M

    2006-01-01

    Early manifestation of breast cancer is often very subtle and is displayed in a complex and variable pattern of normal anatomy that may obscure the disease. The use of dual-energy techniques, that can remove the structural noise, and contrast media, that enhance the region surrounding the tumour, could help us to improve the detectability of the lesions. The aim of this work is to investigate the use of an iodine-based contrast medium in mammography with two different double exposure techniques: K-edge subtraction mammography and temporal subtraction mammography. Both techniques have been investigated by using an ideal source, like monochromatic beams produced at a synchrotron radiation facility and a clinical digital mammography system. A dedicated three-component phantom containing cavities filled with different iodine concentrations has been developed and used for measurements. For each technique, information about the minimum iodine concentration, which provides a significant enhancement of the detectability of the pathology by minimizing the risk due to high dose and high concentration of contrast medium, has been obtained. In particular, for cavities of 5 and 8 mm in diameter filled with iodine solutions, the minimum concentration needed to obtain a contrast-to-noise ratio of 5 with a mean glandular dose of 2 mGy has been calculated. The minimum concentrations estimated with monochromatic beams and K-edge subtraction mammography are 0.9 mg ml -1 and 1.34 mg ml -1 for the biggest and smallest details, respectively, while for temporal subtraction mammography they are 0.84 mg ml -1 and 1.31 mg ml -1 . With the conventional clinical system the minimum concentrations for the K-edge subtraction mammography are 4.13 mg ml -1 (8 mm diameter) and 5.75 mg ml -1 (5 mm diameter), while for the temporal subtraction mammography they are 1.01 mg ml -1 (8 mm diameter) and 1.57 mg ml -1 (5 mm diameter)

  18. A study on the method for cancelling the background noise of the impact signal

    International Nuclear Information System (INIS)

    Kim, J. S.; Ham, C. S.; Park, J. H.

    1998-01-01

    In this paper, we compared the noise canceller (time domain analysis method) to the spectral subtraction (frequency domain analysis method) for cancelling background noise when the Loose Part Monitoring System's accelerometers combined the noise signal with the impact signal if the impact signal exists. In the operation of a nuclear power plant monitoring, alarm triggering occurs due to a peak signal in the background noise, an amplitude increase by component operation such as control rod movement or abrupt pump operation. This operation causes the background noise in LPMS. Thus this noise inputs to LPMS together with the impact signal. In case that this noise amplitude is very large comparing to that of the impact signal, we may not analyze the impact position and mass estimation. We analyzed two methods for cancelling background noise. First, we evaluate the signal to noise ratio utilizing the noise canceller. Second, we evaluate the signal to noise ratio utilizing the spectral subtraction. The evaluation resulted superior the noise canceller to the spectral subtraction on the signal to noise ratio

  19. Manual for the Jet Event and Background Simulation Library(JEBSimLib)

    Energy Technology Data Exchange (ETDEWEB)

    Heinz, Matthias [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Soltz, Ron [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Angerami, Aaron [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-29

    Jets are the collimated streams of particles resulting from hard scattering in the initial state of high-energy collisions. In heavy-ion collisions, jets interact with the quark-gluon plasma (QGP) before freezeout, providing a probe into the internal structure and properties of the QGP. In order to study jets, background must be subtracted from the measured event, potentially introducing a bias. We aim to understand and quantify this subtraction bias. PYTHIA, a library to simulate pure jet events, is used to simulate a model for a signature with one pure jet (a photon) and one quenched jet, where all quenched particle momenta are reduced by a user-de ned constant fraction. Background for the event is simulated using multiplicity values generated by the TRENTO initial state model of heavy-ion collisions fed into a thermal model consisting of a 3-dimensional Boltzmann distribution for particle types and momenta. Data from the simulated events is used to train a statistical model, which computes a posterior distribution of the quench factor for a data set. The model was tested rst on pure jet events and then on full events including the background. This model will allow for a quantitative determination of biases induced by various methods of background subtraction.

  20. Thermal background noise limitations

    Science.gov (United States)

    Gulkis, S.

    1982-01-01

    Modern detection systems are increasingly limited in sensitivity by the background thermal photons which enter the receiving system. Expressions for the fluctuations of detected thermal radiation are derived. Incoherent and heterodyne detection processes are considered. References to the subject of photon detection statistics are given.

  1. Berkeley Low Background Facility

    International Nuclear Information System (INIS)

    Thomas, K. J.; Norman, E. B.; Smith, A. R.; Poon, A. W. P.; Chan, Y. D.; Lesko, K. T.

    2015-01-01

    The Berkeley Low Background Facility (BLBF) at Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California provides low background gamma spectroscopy services to a wide array of experiments and projects. The analysis of samples takes place within two unique facilities; locally within a carefully-constructed, low background laboratory on the surface at LBNL and at the Sanford Underground Research Facility (SURF) in Lead, SD. These facilities provide a variety of gamma spectroscopy services to low background experiments primarily in the form of passive material screening for primordial radioisotopes (U, Th, K) or common cosmogenic/anthropogenic products; active screening via neutron activation analysis for U,Th, and K as well as a variety of stable isotopes; and neutron flux/beam characterization measurements through the use of monitors. A general overview of the facilities, services, and sensitivities will be presented. Recent activities and upgrades will also be described including an overview of the recently installed counting system at SURF (recently relocated from Oroville, CA in 2014), the installation of a second underground counting station at SURF in 2015, and future plans. The BLBF is open to any users for counting services or collaboration on a wide variety of experiments and projects

  2. Using a digital signal processor as a data stream controller for digital subtraction angiography

    International Nuclear Information System (INIS)

    Meng, J.D.; Katz, J.E.

    1991-10-01

    High speed, flexibility, and good arithmetic abilities make digital signal processors (DSP) a good choice as input/output controllers for real time applications. The DSP can be made to pre-process data in real time to reduce data volume, to open early windows on what is being acquired and to implement local servo loops. We present an example of a DSP as an input/output controller for a digital subtraction angiographic imaging system. The DSP pre-processes the raw data, reducing data volume by a factor of two, and is potentially capable of producing real-time subtracted images for immediate display

  3. Subtracted Dispersion Relations for In-medium Meson Correlators in QCD Sum Rules

    Energy Technology Data Exchange (ETDEWEB)

    Florkowski, W; Broniowski, W [The H. Niewodniczanski Institute of Nuclear Physics, Cracow (Poland)

    1999-01-01

    We analyze subtracted dispersion relations for meson correlators at finite baryon density and temperature. Such relations are needed for QCD sum rules. We point out that importance of scattering terms, as well as finite, well-defined subtraction constants. Both are necessary for consistency, in particular for the equality of the longitudinal and transverse correlators in the limit of the vanishing three-momentum of mesons relative to the medium. We present detailed calculations in various mesonic channels of the Fermi gas of nucleons. (author)

  4. Procedures for imaging of hemodialysis fistulas with particular reference to digital subtraction angiography (DSA)

    International Nuclear Information System (INIS)

    Neufang, K.F.R.; Erasmi-Koerber, H.; Wimmer, G.; Koeln Univ.

    1983-01-01

    All angiographic procedures established for imaging of hemodialysis fistulas, such as direct venous angiography, intravenous subtraction angiography and arteriography by direct puncture of the brachial artery of by Seldinger's transfemoral technique, can also be effected with digital image processing. Depending on the angiographic technique, the use of digital subtraction angiography has several advantages: lower doses and concentrations of the contrast agent, lower risk of complications (thrombosis of the fistula, vasospasm) and freedom from pain. In addition, there is a marked reduction of examination time and film cost. (orig.)

  5. Higgs boson production in association with a jet using jettiness subtraction

    Directory of Open Access Journals (Sweden)

    Radja Boughezal

    2015-09-01

    Full Text Available We use the recently proposed jettiness-subtraction scheme to provide the complete calculation of Higgs boson production in association with a jet in hadronic collisions through next-to-next-to-leading order in perturbative QCD. This method exploits the observation that the N-jettiness event-shape variable completely describes the singularity structure of QCD when final-state colored particles are present. Our results are in agreement with a recent computation of the gg and qg partonic initial states based on sector-improved residue subtraction. We present phenomenological results for both fiducial cross sections and distributions at the LHC.

  6. Speech Enhancement by Multichannel Crosstalk Resistant ANC and Improved Spectrum Subtraction

    Directory of Open Access Journals (Sweden)

    Zeng Qingning

    2006-01-01

    Full Text Available A scheme combining multichannel crosstalk resistant adaptive noise cancellation (MCRANC algorithm and improved spectrum subtraction (ISS algorithm is presented to enhance noise carrying speech signals. The scheme would permit locating the microphones in close proximity by virtue of using MCRANC which has the capability of removing the crosstalk effect. MCRANC would also permit canceling out nonstationary noise and making the residual noise more stationary for further treatment by ISS algorithm. Experimental results have indicated that this scheme outperforms many commonly used techniques in the sense of SNR improvement and music effect reduction which is an inevitable byproduct of the spectrum subtraction algorithm.

  7. A Feature Subtraction Method for Image Based Kinship Verification under Uncontrolled Environments

    DEFF Research Database (Denmark)

    Duan, Xiaodong; Tan, Zheng-Hua

    2015-01-01

    The most fundamental problem of local feature based kinship verification methods is that a local feature can capture the variations of environmental conditions and the differences between two persons having a kin relation, which can significantly decrease the performance. To address this problem...... the feature distance between face image pairs with kinship and maximize the distance between non-kinship pairs. Based on the subtracted feature, the verification is realized through a simple Gaussian based distance comparison method. Experiments on two public databases show that the feature subtraction method...

  8. Similarity renormalization group evolution of N N interactions within a subtractive renormalization scheme

    Directory of Open Access Journals (Sweden)

    Durães F.O.

    2010-04-01

    Full Text Available We apply the similarity renormalization group (SRG approach to evolve a nucleon-nucleon (N N interaction in leading-order (LO chiral effective field theory (ChEFT, renormalized within the framework of the subtracted kernel method (SKM. We derive a fixed-point interaction and show the renormalization group (RG invariance in the SKM approach. We also compare the evolution of N N potentials with the subtraction scale through a SKM RG equation in the form of a non-relativistic Callan-Symanzik (NRCS equation and the evolution with the similarity cutoff through the SRG transformation.

  9. Parathyroid localizlation by 201Tl-99mTc subtraction scintigraphy

    International Nuclear Information System (INIS)

    Rademaker, P.; Meijer, S.; Piers, D.A.

    1990-01-01

    Subtraction scintigraphy with 201 Tl and 99m Tc for parathyroid localization was performed preoperatively in 13 patients with chronic renal failure and secondary hyperparathyroidism. Twenty of the 37 examined pathological glands were predicted correctly (sensitivity 54%). In 3 patients with recurrent hyperparathyroidism after surgery all pathological glands found at second operation had been detected correctly by subtraction scintigraphy. We conclude that this localization method has a limited value when used prior to first neck exploration in secondary hyperparathyroidism. In persistent hyperparathyroidism after surgery it may play a useful role in localizing missed and ectopic glands. (author)

  10. Subtraction method of computing QCD jet cross sections at NNLO accuracy

    Science.gov (United States)

    Trócsányi, Zoltán; Somogyi, Gábor

    2008-10-01

    We present a general subtraction method for computing radiative corrections to QCD jet cross sections at next-to-next-to-leading order accuracy. The steps needed to set up this subtraction scheme are the same as those used in next-to-leading order computations. However, all steps need non-trivial modifications, which we implement such that that those can be defined at any order in perturbation theory. We give a status report of the implementation of the method to computing jet cross sections in electron-positron annihilation at the next-to-next-to-leading order accuracy.

  11. Subtraction method of computing QCD jet cross sections at NNLO accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Trocsanyi, Zoltan [University of Debrecen and Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen P.O.Box 51 (Hungary)], E-mail: Zoltan.Trocsanyi@cern.ch; Somogyi, Gabor [University of Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland)], E-mail: sgabi@physik.unizh.ch

    2008-10-15

    We present a general subtraction method for computing radiative corrections to QCD jet cross sections at next-to-next-to-leading order accuracy. The steps needed to set up this subtraction scheme are the same as those used in next-to-leading order computations. However, all steps need non-trivial modifications, which we implement such that that those can be defined at any order in perturbation theory. We give a status report of the implementation of the method to computing jet cross sections in electron-positron annihilation at the next-to-next-to-leading order accuracy.

  12. PENGARUH BACKGROUND MAHASISWA TERHADAP KINERJA AKADEMIK

    Directory of Open Access Journals (Sweden)

    Trianasari Angkawijaya

    2014-09-01

    Full Text Available Abstract: The Effect of Students’ Background on Academic Performance. This study examines the effect of background variables on the academic performance of accounting students in a private university in Surabaya. The background variables under study included previous academic performance, prior knowledge on accounting, sex, motivation, preparedness, and expectations. The results show that previous academic performance, motivation, and expectations have positive and significant effects on the students’ overall academic performance in accounting, while preparedness affects only the students’ performance in management accounting. In contrast, prior knowledge on accounting and sex do not give significant impacts to the students’ overall academic performance.These findings indicate the importance of previous aca­demic performance as well as motivation and expectations as background variables in current academic performance. Keywords: students’ background, academic performance, accounting Abstrak: Pengaruh Background Mahasiswa terhadap Kinerja Akademik. Penelitian ini mengkaji pengaruh variabel background terhadap kinerja akademik mahasiswa akuntansi di Universitas Surabaya. Lima variabel background utama dipergunakan, yaitu kinerja akademik sebelumnya, pengetahuan akun­tansi sebelumnya, jenis kelamin, motivasi, kesiapan, dan ekspektasi. Hipotesis diuji menggunakan model regresi linier berganda OLS dan Robust Standar Error. Hasil penelitian memerlihatkan bahwa kinerja akademik sebelumnya, motivasi, dan ekspektasi memiliki pengaruh positif signifikan terhadap kinerja akademik keseluruhan, sementara kesiapan memberikan pengaruh positif hanya pada kinerja akademik akuntansi manajemen. Sebaliknya, pengetahuan akuntansi sebelumnya dan jenis kelamin tidak memberi­kan pengaruh signifikan terhadap kinerja akademik keseluruhan. Temuan ini mengindikasikan bahwa kinerja akademik sebelumnya beserta motivasi dan ekspektasi adalah variabel background

  13. The Cosmic Microwave Background

    Directory of Open Access Journals (Sweden)

    Jones Aled

    1998-01-01

    Full Text Available We present a brief review of current theory and observations of the cosmic microwave background (CMB. New predictions for cosmological defect theories and an overview of the inflationary theory are discussed. Recent results from various observations of the anisotropies of the microwave background are described and a summary of the proposed experiments is presented. A new analysis technique based on Bayesian statistics that can be used to reconstruct the underlying sky fluctuations is summarised. Current CMB data is used to set some preliminary constraints on the values of fundamental cosmological parameters $Omega$ and $H_circ$ using the maximum likelihood technique. In addition, secondary anisotropies due to the Sunyaev-Zel'dovich effect are described.

  14. Detection of intracranial aneurysms using three-dimensional multidetector-row CT angiography: Is bone subtraction necessary?

    International Nuclear Information System (INIS)

    Hwang, Seung Bae; Kwak, Hyo Sung; Han, Young Min; Chung, Gyung Ho

    2011-01-01

    Purpose: The aim of this study was to evaluate the usefulness of three-dimensional CT angiography (3D CTA) with bone subtraction in a comparison with 3D CTA without bone subtraction for the detection of intracranial aneurysms. Materials and methods: Among 337 consecutive patients who had intracranial aneurysms detected on 3D CTA, 170 patients who underwent digital subtraction angiography (DSA) were included in the study. CTA was performed with a 16-slice multidetector-row CT (MDCT) scanner. We created the 3D reconstruction images with and without bone subtraction by using the volume rendering technique. Three neuroradiologists in a blinded fashion interpreted both 3D CTA images with and without bone subtraction. The diagnostic accuracy of both techniques was evaluated using the alternative free-response receiver operating characteristic (ROC) analysis. The sensitivity and positive predictive value were also evaluated. Results: A total of 200 aneurysms (size: 2-23 mm) were detected in 170 patients. The area under the receiver operating characteristic curve (Az) for 3D CTA with bone subtraction (mean, Az = 0.933) was significantly higher than that for 3D CTA without bone subtraction (mean, Az = 0.879) for all observers (P < 0.05). The sensitivity of 3D CTA with bone subtraction for three observers was 90.0, 92.0 and 92.5%, respectively, while the sensitivity of 3D CTA without bone subtraction was 83.5, 83.5 and 87.5%, respectively. No significant difference in positive predictive value was observed between the two modalities. Conclusions: 3D CTA with bone subtraction showed significantly higher diagnostic accuracy for the detection of intracranial aneurysms as compared to 3D CTA without bone subtraction.

  15. Robust and distributed hypothesis testing

    CERN Document Server

    Gül, Gökhan

    2017-01-01

    This book generalizes and extends the available theory in robust and decentralized hypothesis testing. In particular, it presents a robust test for modeling errors which is independent from the assumptions that a sufficiently large number of samples is available, and that the distance is the KL-divergence. Here, the distance can be chosen from a much general model, which includes the KL-divergence as a very special case. This is then extended by various means. A minimax robust test that is robust against both outliers as well as modeling errors is presented. Minimax robustness properties of the given tests are also explicitly proven for fixed sample size and sequential probability ratio tests. The theory of robust detection is extended to robust estimation and the theory of robust distributed detection is extended to classes of distributions, which are not necessarily stochastically bounded. It is shown that the quantization functions for the decision rules can also be chosen as non-monotone. Finally, the boo...

  16. Robustness of IPTV business models

    NARCIS (Netherlands)

    Bouwman, H.; Zhengjia, M.; Duin, P. van der; Limonard, S.

    2008-01-01

    The final stage in the STOF method is an evaluation of the robustness of the design, for which the method provides some guidelines. For many innovative services, the future holds numerous uncertainties, which makes evaluating the robustness of a business model a difficult task. In this chapter, we

  17. Robustness Evaluation of Timber Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

    2009-01-01

    Robustness of structural systems has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure.......Robustness of structural systems has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure....

  18. COBE diffuse infrared background experiment observations of the galactic bulge

    Science.gov (United States)

    Weiland, J. L.; Arendt, R. G.; Berriman, G. B.; Dwek, E.; Freudenreich, H. T.; Hauser, M. G.; Kelsall, T.; Lisse, C. M.; Mitra, M.; Moseley, S. H.

    1994-01-01

    Low angular resolution maps of the Galactic bulge at 1.25, 2.2, 3.5, and 4.9 micrometers obtained by the Diffuse Infrared Background Experiment (DIRBE) onboard NASA's Cosmic Background Explorer (COBE) are presented. After correction for extinction and subtraction of an empirical model for the Galactic disk, the surface brightness distribution of the bulge resembles a flattened ellipse with a minor-to-major axis ratio of approximately 0.6. The bulge minor axis scale height is found to be 2.1 deg +/- 0.2 deg for all four near-infrared wavelengths. Asymmetries in the longitudinal distribution of bulge brightness contours are qualitatively consistent with those expected for a triaxial bar with its near end in the first Galactic quadrant (0 deg less than l less than 90 deg). There is no evidence for an out-of-plane tilt of such a bar.

  19. A Novel Approach to model EPIC variable background

    Science.gov (United States)

    Marelli, M.; De Luca, A.; Salvetti, D.; Belfiore, A.

    2017-10-01

    One of the main aim of the EXTraS (Exploring the X-ray Transient and variable Sky) project is to characterise the variability of serendipitous XMM-Newton sources within each single observation. Unfortunately, 164 Ms out of the 774 Ms of cumulative exposure considered (21%) are badly affected by soft proton flares, hampering any classical analysis of field sources. De facto, the latest releases of the 3XMM catalog, as well as most of the analysis in literature, simply exclude these 'high background' periods from analysis. We implemented a novel SAS-indipendent approach to produce background-subtracted light curves, which allows to treat the case of very faint sources and very bright proton flares. EXTraS light curves of 3XMM-DR5 sources will be soon released to the community, together with new tools we are developing.

  20. Robust statistical methods with R

    CERN Document Server

    Jureckova, Jana

    2005-01-01

    Robust statistical methods were developed to supplement the classical procedures when the data violate classical assumptions. They are ideally suited to applied research across a broad spectrum of study, yet most books on the subject are narrowly focused, overly theoretical, or simply outdated. Robust Statistical Methods with R provides a systematic treatment of robust procedures with an emphasis on practical application.The authors work from underlying mathematical tools to implementation, paying special attention to the computational aspects. They cover the whole range of robust methods, including differentiable statistical functions, distance of measures, influence functions, and asymptotic distributions, in a rigorous yet approachable manner. Highlighting hands-on problem solving, many examples and computational algorithms using the R software supplement the discussion. The book examines the characteristics of robustness, estimators of real parameter, large sample properties, and goodness-of-fit tests. It...

  1. Background-Modeling-Based Adaptive Prediction for Surveillance Video Coding.

    Science.gov (United States)

    Zhang, Xianguo; Huang, Tiejun; Tian, Yonghong; Gao, Wen

    2014-02-01

    The exponential growth of surveillance videos presents an unprecedented challenge for high-efficiency surveillance video coding technology. Compared with the existing coding standards that were basically developed for generic videos, surveillance video coding should be designed to make the best use of the special characteristics of surveillance videos (e.g., relative static background). To do so, this paper first conducts two analyses on how to improve the background and foreground prediction efficiencies in surveillance video coding. Following the analysis results, we propose a background-modeling-based adaptive prediction (BMAP) method. In this method, all blocks to be encoded are firstly classified into three categories. Then, according to the category of each block, two novel inter predictions are selectively utilized, namely, the background reference prediction (BRP) that uses the background modeled from the original input frames as the long-term reference and the background difference prediction (BDP) that predicts the current data in the background difference domain. For background blocks, the BRP can effectively improve the prediction efficiency using the higher quality background as the reference; whereas for foreground-background-hybrid blocks, the BDP can provide a better reference after subtracting its background pixels. Experimental results show that the BMAP can achieve at least twice the compression ratio on surveillance videos as AVC (MPEG-4 Advanced Video Coding) high profile, yet with a slightly additional encoding complexity. Moreover, for the foreground coding performance, which is crucial to the subjective quality of moving objects in surveillance videos, BMAP also obtains remarkable gains over several state-of-the-art methods.

  2. Robust video object cosegmentation.

    Science.gov (United States)

    Wang, Wenguan; Shen, Jianbing; Li, Xuelong; Porikli, Fatih

    2015-10-01

    With ever-increasing volumes of video data, automatic extraction of salient object regions became even more significant for visual analytic solutions. This surge has also opened up opportunities for taking advantage of collective cues encapsulated in multiple videos in a cooperative manner. However, it also brings up major challenges, such as handling of drastic appearance, motion pattern, and pose variations, of foreground objects as well as indiscriminate backgrounds. Here, we present a cosegmentation framework to discover and segment out common object regions across multiple frames and multiple videos in a joint fashion. We incorporate three types of cues, i.e., intraframe saliency, interframe consistency, and across-video similarity into an energy optimization framework that does not make restrictive assumptions on foreground appearance and motion model, and does not require objects to be visible in all frames. We also introduce a spatio-temporal scale-invariant feature transform (SIFT) flow descriptor to integrate across-video correspondence from the conventional SIFT-flow into interframe motion flow from optical flow. This novel spatio-temporal SIFT flow generates reliable estimations of common foregrounds over the entire video data set. Experimental results show that our method outperforms the state-of-the-art on a new extensive data set (ViCoSeg).

  3. Evolution favors protein mutational robustness in sufficiently large populations

    Directory of Open Access Journals (Sweden)

    Venturelli Ophelia S

    2007-07-01

    Full Text Available Abstract Background An important question is whether evolution favors properties such as mutational robustness or evolvability that do not directly benefit any individual, but can influence the course of future evolution. Functionally similar proteins can differ substantially in their robustness to mutations and capacity to evolve new functions, but it has remained unclear whether any of these differences might be due to evolutionary selection for these properties. Results Here we use laboratory experiments to demonstrate that evolution favors protein mutational robustness if the evolving population is sufficiently large. We neutrally evolve cytochrome P450 proteins under identical selection pressures and mutation rates in populations of different sizes, and show that proteins from the larger and thus more polymorphic population tend towards higher mutational robustness. Proteins from the larger population also evolve greater stability, a biophysical property that is known to enhance both mutational robustness and evolvability. The excess mutational robustness and stability is well described by mathematical theory, and can be quantitatively related to the way that the proteins occupy their neutral network. Conclusion Our work is the first experimental demonstration of the general tendency of evolution to favor mutational robustness and protein stability in highly polymorphic populations. We suggest that this phenomenon could contribute to the mutational robustness and evolvability of viruses and bacteria that exist in large populations.

  4. Addition Table of Colours: Additive and Subtractive Mixtures Described Using a Single Reasoning Model

    Science.gov (United States)

    Mota, A. R.; Lopes dos Santos, J. M. B.

    2014-01-01

    Students' misconceptions concerning colour phenomena and the apparent complexity of the underlying concepts--due to the different domains of knowledge involved--make its teaching very difficult. We have developed and tested a teaching device, the addition table of colours (ATC), that encompasses additive and subtractive mixtures in a single…

  5. Visualization of the renal venous system by renal arteriography with digital subtraction angiography

    International Nuclear Information System (INIS)

    Nagai, Jun

    1989-01-01

    The purpose of this study was to obtain vivid and precise images of intrarenal venous branching using DSA for renal arteriography. The type of system used was an ADAC DPS-4100C with 70-80 kVp, and 320 mA, 25-50 msec at 6 frames/sec. The duration was 10 sec and the matrix size was 512x512. In order to retain clear subtracted images of intrarenal venous branching with minimal noise the three frames were selected on the time-density curve of DSA: (Fig.3). 1) a frame on which renal arteries disappear (frame X), 2) the frame with highest renal venous density value as (frame Y), 3) the difference of the nephrogram density between X and Y frames in which only the density of the nephrogram decreases (frame Z). The mask image is the image subtracted by the equation of the weighted averaging method on X and Z frame and is subtracted from the image of Y frame in the final step. By this method, 40 kidneys in 36 patients were studied, and the intrarenal venous branches up to the interlobar vein was clearly demonstrated in 28 of these cases (70%). This method is useful to estimate the extent of intrarenal lesions and detect abnormal renal blood flow compared with conventional temporal subtraction method. (author)

  6. Application of the singularity subtraction method for (d,p) reactions on light nuclei

    International Nuclear Information System (INIS)

    Borbely, I.

    1974-01-01

    It is shown that the method of subtraction the nearest singularity can be used successfully for data processing of (d,p) reactions. The data on the nuclear structure, thus obtained, can then be used for a more efficient study of the reaction mechanism with the use of traditional methods

  7. Misconception on Addition and Subtraction of Fraction at Primary School Students in Fifth-Grade

    Science.gov (United States)

    Trivena, V.; Ningsih, A. R.; Jupri, A.

    2017-09-01

    This study aims to investigate the mastery concept of the student in mathematics learning especially in addition and subtraction of fraction at primary school level. By using qualitative research method, the data were collected from 23 grade five students (10-11-year-old). Instruments included a test, that is accompanied by Certainty Response Index (CRI) and interview with students and teacher. The result of the test has been obtained, then processed by analyzing the student’s answers for each item and then grouped by the CRI categories that combined with the results of the interview with students and teacher. The results showed that student’s mastery-concept on additional and subtraction dominated by category ‘misconception’. So, we can say that mastery-concept on addition and subtraction of fraction at fifth-grade students is still low. Finally, the impact can make most of primary student think that learning addition and subtraction of fraction in mathematics is difficult.

  8. Infinity subtraction in a quantum field theory of charges and monopoles

    International Nuclear Information System (INIS)

    Panagiotakopoulos, C.

    1982-03-01

    Subtraction of ultraviolet infinities in Zwanziger's local quantum field theory of charges and monopoles is described. It involves an infinite number of graphs. The whole programme rests on the assumption that the infinite summations involved do not give rise to pathological situations and the Ward identities are satisfied even after the string cancellations. The resulting finite theory is Lorentz invariant. (author)

  9. Dissociation of Subtraction and Multiplication in the Right Parietal Cortex: Evidence from Intraoperative Cortical Electrostimulation

    Science.gov (United States)

    Yu, Xiaodan; Chen, Chuansheng; Pu, Song; Wu, Chenxing; Li, Yongnian; Jiang, Tao; Zhou, Xinlin

    2011-01-01

    Previous research has consistently shown that the left parietal cortex is critical for numerical processing, but the role of the right parietal lobe has been much less clear. This study used the intraoperative cortical electrical stimulation approach to investigate neural dissociation in the right parietal cortex for subtraction and…

  10. [Development of a digital chest phantom for studies on energy subtraction techniques].

    Science.gov (United States)

    Hayashi, Norio; Taniguchi, Anna; Noto, Kimiya; Shimosegawa, Masayuki; Ogura, Toshihiro; Doi, Kunio

    2014-03-01

    Digital chest phantoms continue to play a significant role in optimizing imaging parameters for chest X-ray examinations. The purpose of this study was to develop a digital chest phantom for studies on energy subtraction techniques under ideal conditions without image noise. Computed tomography (CT) images from the LIDC (Lung Image Database Consortium) were employed to develop a digital chest phantom. The method consisted of the following four steps: 1) segmentation of the lung and bone regions on CT images; 2) creation of simulated nodules; 3) transformation to attenuation coefficient maps from the segmented images; and 4) projection from attenuation coefficient maps. To evaluate the usefulness of digital chest phantoms, we determined the contrast of the simulated nodules in projection images of the digital chest phantom using high and low X-ray energies, soft tissue images obtained by energy subtraction, and "gold standard" images of the soft tissues. Using our method, the lung and bone regions were segmented on the original CT images. The contrast of simulated nodules in soft tissue images obtained by energy subtraction closely matched that obtained using the gold standard images. We thus conclude that it is possible to carry out simulation studies based on energy subtraction techniques using the created digital chest phantoms. Our method is potentially useful for performing simulation studies for optimizing the imaging parameters in chest X-ray examinations.

  11. Application of digital subtraction angiography in disease of large cardiac vessel

    Energy Technology Data Exchange (ETDEWEB)

    Arisawa, Jun; Sone, Shusuke; Morimoto, Shizuo; Ikezoe, Junpei; Higashibara, Tokuro; Hanayama, Masayuki

    1983-06-01

    Digital subtraction angiography (DSA) was performed in 31 cases of disease of large cardiac vessel. DSA was useful for the diagnosis of aortic aneurysm and malformation of large vessels, follow-up after A-C bypass operation and Blalock's shunt operation for tetralogy of Fallot and as an adjuvant modality in cardiac catheterization.

  12. Application of digital subtraction angiography in disease of large cardiac vessel

    International Nuclear Information System (INIS)

    Arisawa, Jun; Sone, Shusuke; Morimoto, Shizuo; Ikezoe, Junpei; Higashibara, Tokuro; Hanayama, Masayuki

    1983-01-01

    Digital subtraction angiography (DSA) was performed in 31 cases of disease of large cardiac vessel. DSA was useful for the diagnosis of aortic aneurysm and malformation of large vessels, follow-up after A-C bypass operation and Blalock's shunt operation for tetralogy of Fallot and as an adjuvant modality in cardiac catheterization. (Chiba, N.)

  13. [X-ray semiotics of sialolithiasis in functional digital subtraction sialography].

    Science.gov (United States)

    Iudin, L A; Kondrashin, S A; Afanas'ev, V V; Shchipskiĭ, A V

    1995-01-01

    Twenty-seven patients with sialolithiasis were examined using functional subtraction sialography developed by the authors. Differential diagnostic signs characterizing the degree of involvement of the salivary gland were defined. High efficacy of the method helps correctly plan the treatment strategy.

  14. On Semiotics and Jumping Frogs: The Role of Gesture in the Teaching of Subtraction

    Science.gov (United States)

    Farrugia, Marie Therese

    2017-01-01

    In this article, I describe a research/teaching experience I undertook with a class of 5-year-old children in Malta. The topic was subtraction on the number line. I interpret the teaching/learning process through a semiotic perspective. In particular, I highlight the role played by the gesture of forming "frog jumps" on the number line.…

  15. The role of contrast-enhanced digital subtraction MRI in the diagnosis of vertebral metastasic tumors

    International Nuclear Information System (INIS)

    Xiao Yeyu; Yang Jun; Qi Weili; Liu Qize; Hong Bikai; Wu Renhua

    2008-01-01

    Objective: To evaluate the contrast-enhanced digital subtraction MRI in the diagnosis of vertebral metastasic tumors. Methods 66 vertebral metastasic tumors in 43 patients were examined with conventional MRI (T 1 WI, STIR and Contrast-enhanced T 1 WI) and contrast-enhanced digital subtraction MR imaging. All lesions were histologically proved. The quantity and characteristic imaging signs (including spiculation, bull eye sign and irregular edge) of lesions were detected separately by different sequences. K independent samples test was used. Results: The detection rates of 35 vertebral metastasic tumors with vertebral morphological changes were same in all MR sequences. But in the other 31 lesions without vertebral morphological changes, the detection rates were different and STIR was the highest in all sequences. Contrast-enhanced digital subtraction MRI was more sensitive than all the conventional MR sequences in finding characteristic imaging signs with statistically significant differences. Conclusion: Contrast enhanced subtraction MRI is an useful and convenient technique which has great value in finding vertebral metastasic tumors and depicting the characteristic imaging signs. (authors)

  16. Geometrical accuracy of metallic objects produced with additive or subtractive manufacturing: A comparative in vitro study.

    Science.gov (United States)

    Braian, Michael; Jönsson, David; Kevci, Mir; Wennerberg, Ann

    2018-04-06

    To evaluate the accuracy and precision of objects produced by additive manufacturing systems (AM) for use in dentistry and to compare with subtractive manufacturing systems (SM). Ten specimens of two geometrical objects were produced by five different AM machines and one SM machine. Object A mimics an inlay-shaped object, while object B imitates a four-unit bridge model. All the objects were sorted into different measurement dimensions (x, y, z), linear distances, angles and corner radius. None of the additive manufacturing or subtractive manufacturing groups presented a perfect match to the CAD file with regard to all parameters included in the present study. Considering linear measurements, the precision for subtractive manufacturing group was consistent in all axes for object A, presenting results of additive manufacturing groups had consistent precision in the x-axis and y-axis but not in the z-axis. With regard to corner radius measurements, the SM group had the best overall accuracy and precision for both objects A and B when compared to the AM groups. Within the limitations of this in vitro study, the conclusion can be made that subtractive manufacturing presented overall precision on all measurements below 0.050mm. The AM machines also presented fairly good precision, additive techniques are now being implemented. Thus all these production techniques need to be tested, compared and validated. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

  17. Addition and Subtraction but Not Multiplication and Division Cause Shifts of Spatial Attention

    Directory of Open Access Journals (Sweden)

    Mengjin Li

    2018-05-01

    Full Text Available Many studies have shown that solving addition and subtraction problems can induce overt shifts of spatial attention. In particular, right-side targets are detected faster than left-side targets when preceded by an addition operation, while left-side targets are detected faster than right-side targets when preceded by a subtraction operation. However, the interaction between space and arithmetic in multiplication or division is hardly studied and remains controversial. In order to make a strong case for the interaction between space and mental arithmetic, we attempted to replicate the spatial-arithmetic association in addition and subtraction (Experiment 1, and at the same time investigated whether shift of spatial attention would also be induced by multiplication or division operations (Experiment 2. We found that solving addition problems facilitated the detection of right-side targets, whereas left-side targets were detected faster after solving subtraction problems. However, no interaction between space and arithmetic operation was observed in multiplication or division. The implication of these findings is discussed.

  18. Non-perturbative subtractions in the heavy quark effective field theory

    International Nuclear Information System (INIS)

    Maiani, L.; Martinelli, G.; Sachrajda, C.T.

    1992-01-01

    We demonstrate the presence of ultraviolet power divergences in the O(1/m h ) corrections to matrix elements of hadronic operators containing a heavy quark field (where m h is the mass of the heavy quark). These power divergences must be subtracted non-perturbatively. The implications for lattice computations are discussed in detail. (orig.)

  19. Digital subtraction angiography and intraarterial contrast medium injection for coronary examinations

    Energy Technology Data Exchange (ETDEWEB)

    Tobio, R; Kallmeyer, C; Castello, J

    1985-01-01

    Digital subtraction angiography (DSA) is an established method of vasography, most extensively used as i.v. DSA. Intraarterial injection, however, applying selective or non-selective contrast medium injection, seems to be at least as important a technique although it has not yet met with corresponding interest. The article explains advantages of the technique for angiographic examinations, in particular of coronary angiography.

  20. Digital subtraction angiography - a new approach to brain death determination in the newborn

    International Nuclear Information System (INIS)

    Albertini, A.; Schonfeld, S.; Hiatt, M.; Hegyi, T.

    1993-01-01

    The diagnosis of brain death in the newborn infants is elusive and often difficult. The lack of cerebral blood flow has become an identified criterion for loss of cerebral function. The diagnosis can be obtained by the technique of digital subtraction angiography, which is presented in two case reports demonstrating the utility of this technique. (orig.)

  1. Heritage Language Learners in Mixed Spanish Classes: Subtractive Practices and Perceptions of High School Spanish Teachers

    Science.gov (United States)

    Randolph, Linwood J., Jr.

    2017-01-01

    This qualitative study investigated the language ideologies and instructional practices of an entire Spanish language faculty at a high school in a new gateway state for immigration. The study examined additive and subtractive practices of teachers as they strived to teach Spanish to heritage language learners (HLLs) enrolled in mixed…

  2. Does one see gluon condensation after subtraction of mean field perturbation theory from Monte Carlo data

    International Nuclear Information System (INIS)

    Schlichting, H.

    1985-01-01

    We do a linearised mean field calculation in axial gauge for the four dimensional mixed fundamental adjoint SU(2) lattice gauge theory and extract the gluon condensate parameter from the expectation values of the plaquette and the action by subtracting mean field perturbation theory from Monte Carlo data. (orig.)

  3. Low-cost addition-subtraction sequences for the final exponentiation computation in pairings

    DEFF Research Database (Denmark)

    Guzmán-Trampe, Juan E; Cruz-Cortéz, Nareli; Dominguez Perez, Luis

    2014-01-01

    In this paper, we address the problem of finding low cost addition–subtraction sequences for situations where a doubling step is significantly cheaper than a non-doubling one. One application of this setting appears in the computation of the final exponentiation step of the reduced Tate pairing d...

  4. Proximal caries detection using digital subtraction radiography in the artificial caries activity model

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Hoon; Lee, Gi Ja; Choi, Sam Jin; Park, Young Ho; Kim, Kyung Soo; Jin, Hyun Seok; Hong, Kyung Won; Oh, Berm Seok; Park, Hun Kuk [Department of Biomedical Engineering, School of Medicine, Kyung Hee University, Seoul (Korea, Republic of); Choi, Yong Suk; Hwang, Eui Hwan [Department of Oral and Maxillofacial Radiology, Institute of Oral Biology, School of Dentistry, Kyung Hee University, Seoul (Korea, Republic of)

    2009-03-15

    The purpose of the experiment was to evaluating the diagnostic ability of dental caries detection using digital subtraction in the artificial caries activity model. Digital radiographs of five teeth with 8 proximal surfaces were obtained by CCD sensor (Kodak RVG 6100 using a size no.2). The digital radiographic images and subtraction images from artificial proximal caries were examined and interpreted. In this study, we proposed novel caries detection method which could diagnose the dental proximal caries from single digital radiographic image. In artificial caries activity model, the range of lesional depth was 572-1,374 {mu}m and the range of lesional area was 36.95-138.52 mm{sup 2}. The lesional depth and the area were significantly increased with demineralization time (p<0.001). Furthermore, the proximal caries detection using digital subtraction radiography showed high detection rate compared to the proximal caries examination using simple digital radiograph. The results demonstrated that the digital subtraction radiography from single radiographic image of artificial caries was highly efficient in the detection of dental caries compared to the data from simple digital radiograph.

  5. Proximal caries detection using digital subtraction radiography in the artificial caries activity model

    International Nuclear Information System (INIS)

    Park, Jong Hoon; Lee, Gi Ja; Choi, Sam Jin; Park, Young Ho; Kim, Kyung Soo; Jin, Hyun Seok; Hong, Kyung Won; Oh, Berm Seok; Park, Hun Kuk; Choi, Yong Suk; Hwang, Eui Hwan

    2009-01-01

    The purpose of the experiment was to evaluating the diagnostic ability of dental caries detection using digital subtraction in the artificial caries activity model. Digital radiographs of five teeth with 8 proximal surfaces were obtained by CCD sensor (Kodak RVG 6100 using a size no.2). The digital radiographic images and subtraction images from artificial proximal caries were examined and interpreted. In this study, we proposed novel caries detection method which could diagnose the dental proximal caries from single digital radiographic image. In artificial caries activity model, the range of lesional depth was 572-1,374 μm and the range of lesional area was 36.95-138.52 mm 2 . The lesional depth and the area were significantly increased with demineralization time (p<0.001). Furthermore, the proximal caries detection using digital subtraction radiography showed high detection rate compared to the proximal caries examination using simple digital radiograph. The results demonstrated that the digital subtraction radiography from single radiographic image of artificial caries was highly efficient in the detection of dental caries compared to the data from simple digital radiograph.

  6. Real-Time Adaptive Foreground/Background Segmentation

    Directory of Open Access Journals (Sweden)

    Sridha Sridharan

    2005-08-01

    Full Text Available The automatic analysis of digital video scenes often requires the segmentation of moving objects from a static background. Historically, algorithms developed for this purpose have been restricted to small frame sizes, low frame rates, or offline processing. The simplest approach involves subtracting the current frame from the known background. However, as the background is rarely known beforehand, the key is how to learn and model it. This paper proposes a new algorithm that represents each pixel in the frame by a group of clusters. The clusters are sorted in order of the likelihood that they model the background and are adapted to deal with background and lighting variations. Incoming pixels are matched against the corresponding cluster group and are classified according to whether the matching cluster is considered part of the background. The algorithm has been qualitatively and quantitatively evaluated against three other well-known techniques. It demonstrated equal or better segmentation and proved capable of processing 320×240 PAL video at full frame rate using only 35%–40% of a 1.8 GHz Pentium 4 computer.

  7. Family Background and Entrepreneurship

    DEFF Research Database (Denmark)

    Lindquist, Matthew J.; Sol, Joeri; Van Praag, Mirjam

    Vast amounts of money are currently being spent on policies aimed at promoting entrepreneurship. The success of such policies, however, rests in part on the assumption that individuals are not ‘born entrepreneurs’. In this paper, we assess the importance of family background and neighborhood...... effects as determinants of entrepreneurship. We start by estimating sibling correlations in entrepreneurship. We find that between 20 and 50 percent of the variance in different entrepreneurial outcomes is explained by factors that siblings share. The average is 28 percent. Allowing for differential...... entrepreneurship does play a large role, as do shared genes....

  8. Malaysia; Background Paper

    OpenAIRE

    International Monetary Fund

    1996-01-01

    This Background Paper on Malaysia examines developments and trends in the labor market since the mid-1980s. The paper describes the changes in the employment structure and the labor force. It reviews wages and productivity trends and their effects on unit labor cost. The paper highlights that Malaysia’s rapid growth, sustained since 1987, has had a major impact on the labor market. The paper outlines the major policy measures to address the labor constraints. It also analyzes Malaysia’s recen...

  9. Bone images from dual-energy subtraction chest radiography in the detection of rib fractures

    Energy Technology Data Exchange (ETDEWEB)

    Szucs-Farkas, Zsolt, E-mail: zsolt.szuecs@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Lautenschlager, Katrin, E-mail: katrin@students.unibe.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Flach, Patricia M., E-mail: patricia.flach@irm.unibe.ch [Institute of Forensic Medicine, University of Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Ott, Daniel, E-mail: daniel.ott@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Strautz, Tamara, E-mail: tamara.strautz@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Vock, Peter, E-mail: peter.vock@insel.ch [Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland); Ruder, Thomas D., E-mail: thomas.ruder@irm.unibe.ch [Institute of Forensic Medicine, University of Bern, Freiburgstrasse 4, Bern CH-3010 (Switzerland)

    2011-08-15

    Objective: To assess the sensitivity and image quality of chest radiography (CXR) with or without dual-energy subtracted (ES) bone images in the detection of rib fractures. Materials and methods: In this retrospective study, 39 patients with 204 rib fractures and 24 subjects with no fractures were examined with a single exposure dual-energy subtraction digital radiography system. Three blinded readers first evaluated the non-subtracted posteroanterior and lateral chest radiographs alone, and 3 months later they evaluated the non-subtracted images together with the subtracted posteroanterior bone images. The locations of rib fractures were registered with confidence levels on a 3-grade scale. Image quality was rated on a 5-point scale. Marks by readers were compared with fracture localizations in CT as a standard of reference. Results: The sensivity for fracture detection using both methods was very similar (34.3% with standard CXR and 33.5% with ES-CXR, p = 0.92). At the patient level, both sensitivity (71.8%) and specificity (92.9%) with or without ES were identical. Diagnostic confidence was not significantly different (2.61 with CXR and 2.75 with ES-CXR, p = 0.063). Image quality with ES was rated higher than that on standard CXR (4.08 vs. 3.74, p < 0.001). Conclusions: Despite a better image quality, adding ES bone images to standard radiographs of the chest does not provide better sensitivity or improved diagnostic confidence in the detection of rib fractures.

  10. Pediatric head and neck lesions: assessment of vascularity by MR digital subtraction angiography.

    Science.gov (United States)

    Chooi, Weng Kong; Woodhouse, Neil; Coley, Stuart C; Griffiths, Paul D

    2004-08-01

    Pediatric head and neck lesions can be difficult to characterize on clinical grounds alone. We investigated the use of dynamic MR digital subtraction angiography as a noninvasive adjunct for the assessment of the vascularity of these abnormalities. Twelve patients (age range, 2 days to 16 years) with known or suspected vascular abnormalities were studied. Routine MR imaging, time-of-flight MR angiography, and MR digital subtraction angiography were performed in all patients. The dynamic sequence was acquired in two planes at one frame per second by using a thick section (6-10 cm) selective radio-frequency spoiled fast gradient-echo sequence and an IV administered bolus of contrast material. The images were subtracted from a preliminary mask sequence and viewed as a video-inverted cine loop. In all cases, MR digital subtraction angiography was successfully performed. The technique showed the following: 1) slow flow lesions (two choroidal angiomas, eyelid hemangioma, and scalp venous malformation); 2) high flow lesions that were not always suspected by clinical examination alone (parotid hemangioma, scalp, occipital, and eyelid arteriovenous malformations plus a palatal teratoma); 3) a hypovascular tumor for which a biopsy could be safely performed (Burkitt lymphoma); and 4) a hypervascular tumor of the palate (cystic teratoma). Our early experience suggests that MR digital subtraction angiography can be reliably performed in children of all ages without complication. The technique provided a noninvasive assessment of the vascularity of each lesion that could not always have been predicted on the basis of clinical examination or routine MR imaging alone.

  11. Computed tomography lung iodine contrast mapping by image registration and subtraction

    Science.gov (United States)

    Goatman, Keith; Plakas, Costas; Schuijf, Joanne; Beveridge, Erin; Prokop, Mathias

    2014-03-01

    Pulmonary embolism (PE) is a relatively common and potentially life threatening disease, affecting around 600,000 people annually in the United States alone. Prompt treatment using anticoagulants is effective and saves lives, but unnecessary treatment risks life threatening haemorrhage. The specificity of any diagnostic test for PE is therefore as important as its sensitivity. Computed tomography (CT) angiography is routinely used to diagnose PE. However, there are concerns it may over-report the condition. Additional information about the severity of an occlusion can be obtained from an iodine contrast map that represents tissue perfusion. Such maps tend to be derived from dual-energy CT acquisitions. However, they may also be calculated by subtracting pre- and post-contrast CT scans. Indeed, there are technical advantages to such a subtraction approach, including better contrast-to-noise ratio for the same radiation dose, and bone suppression. However, subtraction relies on accurate image registration. This paper presents a framework for the automatic alignment of pre- and post-contrast lung volumes prior to subtraction. The registration accuracy is evaluated for seven subjects for whom pre- and post-contrast helical CT scans were acquired using a Toshiba Aquilion ONE scanner. One hundred corresponding points were annotated on the pre- and post-contrast scans, distributed throughout the lung volume. Surface-to-surface error distances were also calculated from lung segmentations. Prior to registration the mean Euclidean landmark alignment error was 2.57mm (range 1.43-4.34 mm), and following registration the mean error was 0.54mm (range 0.44-0.64 mm). The mean surface error distance was 1.89mm before registration and 0.47mm after registration. There was a commensurate reduction in visual artefacts following registration. In conclusion, a framework for pre- and post-contrast lung registration has been developed that is sufficiently accurate for lung subtraction

  12. Evaluation of carotid vessel wall enhancement with image subtraction after gadobenate dimeglumine-enhanced MR angiography

    International Nuclear Information System (INIS)

    Sardanelli, Francesco; Di Leo, Giovanni; Aliprandi, Alberto; Flor, Nicola; Papini, Giacomo D.E.; Roccatagliata, Luca; Cotticelli, Biagio; Nano, Giovanni; Cornalba, Gianpaolo

    2009-01-01

    Objectives: This study was aimed at testing the value of image subtraction for evaluating carotid vessel wall enhancement in contrast-enhanced MR angiography (MRA). Materials and methods: IRB approval was obtained. The scans of 81 consecutive patients who underwent carotid MRA with 0.1 mmol/kg of gadobenate dimeglumine were reviewed. Axial carotid 3D T1-weighted fast low-angle shot sequence before and 3 min after contrast injection were acquired and subtracted (enhanced minus unenhanced). Vessel wall enhancement was assigned a four-point score using native or subtracted images from 0 (no enhancement) to 3 (strong enhancement). Stenosis degree was graded according to NASCET. Results: With native images, vessel wall enhancement was detected in 20/81 patients (25%) and in 20/161 carotids (12%), and scored 2.0 ± 0.6 (mean ± standard deviation); with subtracted images, in 21/81 (26%) and 22/161 (14%), and scored 2.5 ± 0.6, respectively (P < 0.001, Sign test). The overall stenosis degree distribution was: mild, 41/161 (25%); moderate, 77/161 (48%); severe, 43/161 (27%). Carotids with moderate stenosis showed vessel wall enhancement with a frequency (17/77, 22%) significantly higher than that observed in carotids with mild stenosis (1/41, 2%) (P = 0.005, Fisher exact test) and higher, even though with borderline significance (P = 0.078, Fisher exact test), than that observed in carotids with severe stenosis (4/43, 9%). Conclusion: Roughly a quarter of patients undergoing carotid MRA showed vessel wall enhancement. Image subtraction improved vessel wall enhancement conspicuity. Vessel wall enhancement seems to be an event relatively independent from the degree of stenosis. Further studies are warranted to define the relation between vessel wall enhancement and histopathology, inflammatory status, and instability.

  13. Robust loss functions for boosting.

    Science.gov (United States)

    Kanamori, Takafumi; Takenouchi, Takashi; Eguchi, Shinto; Murata, Noboru

    2007-08-01

    Boosting is known as a gradient descent algorithm over loss functions. It is often pointed out that the typical boosting algorithm, Adaboost, is highly affected by outliers. In this letter, loss functions for robust boosting are studied. Based on the concept of robust statistics, we propose a transformation of loss functions that makes boosting algorithms robust against extreme outliers. Next, the truncation of loss functions is applied to contamination models that describe the occurrence of mislabels near decision boundaries. Numerical experiments illustrate that the proposed loss functions derived from the contamination models are useful for handling highly noisy data in comparison with other loss functions.

  14. Theoretical Framework for Robustness Evaluation

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2011-01-01

    This paper presents a theoretical framework for evaluation of robustness of structural systems, incl. bridges and buildings. Typically modern structural design codes require that ‘the consequence of damages to structures should not be disproportional to the causes of the damages’. However, although...... the importance of robustness for structural design is widely recognized the code requirements are not specified in detail, which makes the practical use difficult. This paper describes a theoretical and risk based framework to form the basis for quantification of robustness and for pre-normative guidelines...

  15. Robustness of airline route networks

    Science.gov (United States)

    Lordan, Oriol; Sallan, Jose M.; Escorihuela, Nuria; Gonzalez-Prieto, David

    2016-03-01

    Airlines shape their route network by defining their routes through supply and demand considerations, paying little attention to network performance indicators, such as network robustness. However, the collapse of an airline network can produce high financial costs for the airline and all its geographical area of influence. The aim of this study is to analyze the topology and robustness of the network route of airlines following Low Cost Carriers (LCCs) and Full Service Carriers (FSCs) business models. Results show that FSC hubs are more central than LCC bases in their route network. As a result, LCC route networks are more robust than FSC networks.

  16. Backgrounded but not peripheral

    DEFF Research Database (Denmark)

    Hovmark, Henrik

    2013-01-01

    .e. the schema enters into apparently contradictory constructions of the informants’ local home-base and, possibly, of their identity (cf. Hovmark, 2010). Second, I discuss the status and role of the specific linguistic category in question, i.e. the directional adverbs. On the one hand we claim that the DDAs......In this paper I pay a closer look at the use of the CENTRE-PERIPHERY schema in context. I address two specific issues: first, I show how the CENTRE-PERIPHERY schema, encoded in the DDAs, enters into discourses that conceptualize and characterize a local community as both CENTRE and PERIPHERY, i......; furthermore, the DDAs are backgrounded in discourse. Is it reasonable to claim, rather boldly, that “the informants express their identity in the use of the directional adverb ud ‘out’ etc.”? In the course of this article, however, I suggest that the DDAs in question do contribute to the socio...

  17. OCRWM Backgrounder, January 1987

    International Nuclear Information System (INIS)

    1987-01-01

    The Nuclear Waste Policy Act of 1982 (NWPA) assigns to the US Department of Energy (DOE) responsibility for developing a system to safely and economically transport spent nuclear fuel and high-level radioactive waste from various storage sites to geologic repositories or other facilities that constitute elements of the waste management program. This transportation system will evolve from technologies and capabilities already developed. Shipments of spent fuel to a monitored retrievable storage (MRS) facility could begin as early as 1996 if Congress authorizes its construction. Shipments of spent fuel to a geologic repository are scheduled to begin in 1998. The backgrounder provides an overview of DOE's cask development program. Transportation casks are a major element in the DOE nuclear waste transportation system because they are the primary protection against any potential radiation exposure to the public and transportation workers in the event an accident occurs

  18. Monitored background radiometer

    International Nuclear Information System (INIS)

    Ruel, C.

    1988-01-01

    A monitored background radiometer is described comprising: a thermally conductive housing; low conductivity support means mounted on the housing; a sensing plate mounted on the low conductivity support means and spaced from the housing so as to be thermally insulated from the housing and having an outwardly facing first surface; the sensing plate being disposed relative to the housing to receive direct electromagnetic radiation from sources exterior to the radiometer upon the first surface only; means for controllably heating the sensing plate; first temperature sensitive means to measure the temperature of the housing; and second temperature sensitive means to measure the temperature of the sensing plate, so that the heat flux at the sensing plate may be determined from the temperatures of the housing and sensing plate after calibration of the radiometer by measuring the temperatures of the housing and sensing plate while controllably heating the sensing plate

  19. Robust Portfolio Optimization Using Pseudodistances.

    Science.gov (United States)

    Toma, Aida; Leoni-Aubin, Samuela

    2015-01-01

    The presence of outliers in financial asset returns is a frequently occurring phenomenon which may lead to unreliable mean-variance optimized portfolios. This fact is due to the unbounded influence that outliers can have on the mean returns and covariance estimators that are inputs in the optimization procedure. In this paper we present robust estimators of mean and covariance matrix obtained by minimizing an empirical version of a pseudodistance between the assumed model and the true model underlying the data. We prove and discuss theoretical properties of these estimators, such as affine equivariance, B-robustness, asymptotic normality and asymptotic relative efficiency. These estimators can be easily used in place of the classical estimators, thereby providing robust optimized portfolios. A Monte Carlo simulation study and applications to real data show the advantages of the proposed approach. We study both in-sample and out-of-sample performance of the proposed robust portfolios comparing them with some other portfolios known in literature.

  20. Black hole thermodynamics from a variational principle: asymptotically conical backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    An, Ok Song [SISSA and INFN, Sezione di Trieste,Via Bonomea 265, 34136 Trieste (Italy); Department of Physics, Kim Il Sung University,Ryongnam Dong, TaeSong District, Pyongyang, D.P.R. (Korea, Republic of); ICTP,Strada Costiera 11, 34014 Trieste (Italy); Cvetič, Mirjam [Department of Physics and Astronomy, University of Pennsylvania,209 S 33rd St, Philadelphia, PA 19104 (United States); Center for Applied Mathematics and Theoretical Physics, University of Maribor,Mladinska 3, SI2000 Maribor (Slovenia); Papadimitriou, Ioannis [SISSA and INFN, Sezione di Trieste,Via Bonomea 265, 34136 Trieste (Italy)

    2016-03-14

    The variational problem of gravity theories is directly related to black hole thermodynamics. For asymptotically locally AdS backgrounds it is known that holographic renormalization results in a variational principle in terms of equivalence classes of boundary data under the local asymptotic symmetries of the theory, which automatically leads to finite conserved charges satisfying the first law of thermodynamics. We show that this connection holds well beyond asymptotically AdS black holes. In particular, we formulate the variational problem for N=2 STU supergravity in four dimensions with boundary conditions corresponding to those obeyed by the so called ‘subtracted geometries’. We show that such boundary conditions can be imposed covariantly in terms of a set of asymptotic second class constraints, and we derive the appropriate boundary terms that render the variational problem well posed in two different duality frames of the STU model. This allows us to define finite conserved charges associated with any asymptotic Killing vector and to demonstrate that these charges satisfy the Smarr formula and the first law of thermodynamics. Moreover, by uplifting the theory to five dimensions and then reducing on a 2-sphere, we provide a precise map between the thermodynamic observables of the subtracted geometries and those of the BTZ black hole. Surface terms play a crucial role in this identification.

  1. Robust methods for data reduction

    CERN Document Server

    Farcomeni, Alessio

    2015-01-01

    Robust Methods for Data Reduction gives a non-technical overview of robust data reduction techniques, encouraging the use of these important and useful methods in practical applications. The main areas covered include principal components analysis, sparse principal component analysis, canonical correlation analysis, factor analysis, clustering, double clustering, and discriminant analysis.The first part of the book illustrates how dimension reduction techniques synthesize available information by reducing the dimensionality of the data. The second part focuses on cluster and discriminant analy

  2. A comparative study of additive and subtractive manufacturing for dental restorations.

    Science.gov (United States)

    Bae, Eun-Jeong; Jeong, Il-Do; Kim, Woong-Chul; Kim, Ji-Hwan

    2017-08-01

    Digital systems have recently found widespread application in the fabrication of dental restorations. For the clinical assessment of dental restorations fabricated digitally, it is necessary to evaluate their accuracy. However, studies of the accuracy of inlay restorations fabricated with additive manufacturing are lacking. The purpose of this in vitro study was to evaluate and compare the accuracy of inlay restorations fabricated by using recently introduced additive manufacturing with the accuracy of subtractive methods. The inlay (distal occlusal cavity) shape was fabricated using 3-dimensional image (reference data) software. Specimens were fabricated using 4 different methods (each n=10, total N=40), including 2 additive manufacturing methods, stereolithography apparatus and selective laser sintering; and 2 subtractive methods, wax and zirconia milling. Fabricated specimens were scanned using a dental scanner and then compared by overlapping reference data. The results were statistically analyzed using a 1-way analysis of variance (α=.05). Additionally, the surface morphology of 1 randomly (the first of each specimen) selected specimen from each group was evaluated using a digital microscope. The results of the overlap analysis of the dental restorations indicated that the root mean square (RMS) deviation observed in the restorations fabricated using the additive manufacturing methods were significantly different from those fabricated using the subtractive methods (Padditive manufacturing methods (P=.466). Similarly, no significant differences were found between wax and zirconia, the subtractive methods (P=.986). The observed RMS values were 106 μm for stereolithography apparatus, 113 μm for selective laser sintering, 116 μm for wax, and 119 μm for zirconia. Microscopic evaluation of the surface revealed a fine linear gap between the layers of restorations fabricated using stereolithography apparatus and a grooved hole with inconsistent weak scratches

  3. Low background infrared (LBIR) facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Low background infrared (LBIR) facility was originally designed to calibrate user supplied blackbody sources and to characterize low-background IR detectors and...

  4. Hanford Site background: Part 1, Soil background for nonradioactive analytes

    International Nuclear Information System (INIS)

    1993-04-01

    Volume two contains the following appendices: Description of soil sampling sites; sampling narrative; raw data soil background; background data analysis; sitewide background soil sampling plan; and use of soil background data for the detection of contamination at waste management unit on the Hanford Site

  5. Improvement in visibility of simulated lung nodules on computed radiography (CR) chest images by use of temporal subtraction technique

    International Nuclear Information System (INIS)

    Oda, Nobuhiro; Fujimoto, Keiji; Murakami, Seiichi; Katsuragawa, Shigehiko; Doi, Kunio; Nakata, Hajime

    1999-01-01

    A temporal subtraction image obtained by subtraction of a previous image from a current one can enhance interval change on chest images. In this study, we compared the visibility of simulated lung nodules on CR images with and without temporal subtraction. Chest phantom images without and with simulated nodules were obtained as previous and current images, respectively, by a CR system. Then, subtraction images were produced with an iterative image warping technique. Twelve simulated nodules were attached on various locations of the chest phantom. The diameter of nodules having a CT number of 47 ranged from 3 mm to 10 mm. Seven radiologists subjectively evaluated the visibility of simulated nodules on CR images with and without temporal subtraction using a three-point rating scale (0: invisible, +1: questionable, +2:visible). The minimum diameter of simulated nodules visible at a frequency greater than 50% was 4 mm on the CR images with temporal subtraction and 6 mm on those without. Our results indicated that the subtraction images clearly improved the visibility of simulated nodules. (author)

  6. [Construction of forward and reverse subtracted cDNA libraries between muscle tissue of Meishan and Landrace pigs].

    Science.gov (United States)

    Xu, De-Quan; Zhang, Yi-Bing; Xiong, Yuan-Zhu; Gui, Jian-Fang; Jiang, Si-Wen; Su, Yu-Hong

    2003-07-01

    Using suppression subtractive hybridization (SSH) technique, forward and reverse subtracted cDNA libraries were constructed between Longissimus muscles from Meishan and Landrace pigs. A housekeeping gene, G3PDH, was used to estimate the efficiency of subtractive cDNA. In two cDNA libraries, G3PDH was subtracted very efficiently at appropriate 2(10) and 2(5) folds, respectively, indicating that some differentially expressed genes were also enriched at the same folds and the two subtractive cDNA libraries were very successful. A total of 709 and 673 positive clones were isolated from forward and reverse subtracted cDNA libraries, respectively. Analysis of PCR showed that most of all plasmids in the clones contained 150-750 bp inserts. The construction of subtractive cDNA libraries between muscle tissue from different pig breeds laid solid foundations for isolating and identifying the genes determining muscle growth and meat quality, which will be important to understand the mechanism of muscle growth, determination of meat quality and practice of molecular breeding.

  7. Relation between thallium-201/iodine 123-BMIPP subtraction and fluorine 18 deoxyglucose polar maps in patients with hypertrophic cardiomyopathy.

    Science.gov (United States)

    Ito, Y; Hasegawa, S; Yamaguchi, H; Yoshioka, J; Uehara, T; Nishimura, T

    2000-01-01

    Clinical studies have shown discrepancies in the distribution of thallium-201 and iodine 123-beta-methyl-iodophenylpentadecanoic acid (BMIPP) in patients with hypertrophic cardiomyopathy (HCM). Myocardial uptake of fluorine 18 deoxyglucose (FDG) is increased in the hypertrophic area in HCM. We examined whether the distribution of a Tl-201/BMIPP subtraction polar map correlates with that of an FDG polar map. We normalized to maximum count each Tl-201 and BMIPP bull's-eye polar map of 6 volunteers and obtained a standard Tl-201/BMIPP subtraction polar map by subtracting a normalized BMIPP bull's-eye polar map from a normalized Tl-201 bull's-eye polar map. The Tl-201/BMIPP subtraction polar map was then applied to 8 patients with HCM (mean age 65+/-12 years) to evaluate the discrepancy between Tl-201 and BMIPP distribution. We compared the Tl-201/BMIPP subtraction polar map with an FDG polar map. In patients with HCM, the Tl-201/BMIPP subtraction polar map showed a focal uptake pattern in the hypertrophic area similar to that of the FDG polar map. By quantitative analysis, the severity score of the Tl-201/BMIPP subtraction polar map was significantly correlated with the percent dose uptake of the FDG polar map. These results suggest that this new quantitative method may be an alternative to FDG positron emission tomography for the routine evaluation of HCM.

  8. Synchrotron-based intra-venous K-edge digital subtraction angiography in a pig model: A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Schueltke, Elisabeth [Departments of Surgery, University of Saskatchewan, Saskatoon, SK (Canada); Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK (Canada); Department of Neurological Sciences, Walton Medical Centre, University of Liverpool, Liverpool L97 LJ (United Kingdom)], E-mail: e.schultke@usask.ca; Fiedler, Stefan [European Molecular Biology Laboratory (EMBL), Nottkestrasse 85, 22603 Hamburg (Germany); Nemoz, Christian [European Synchrotron Radiation Facility (ESRF), 6 rue Horowitz, 38043 Grenoble (France); Ogieglo, Lissa [Departments of Surgery, University of Saskatchewan, Saskatoon, SK (Canada); Kelly, Michael E. [Departments of Surgery, University of Saskatchewan, Saskatoon, SK (Canada); Department of Neurosurgery, Section of Cerebrovascular and Endovascular Neurosurgery, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH (United States); Crawford, Paul [Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Herfordshire AL9 7TA (United Kingdom); Esteve, Francois [INSERM U836-ESRF, 6 rue Horowitz, 38043 Grenoble (France); Brochard, Thierry; Renier, Michel; Requardt, Herwig; Le Duc, Geraldine [European Synchrotron Radiation Facility (ESRF), 6 rue Horowitz, 38043 Grenoble (France); Juurlink, Bernhard [Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK (Canada); Meguro, Kotoo [Departments of Surgery, University of Saskatchewan, Saskatoon, SK (Canada)

    2010-03-15

    Background: K-edge digital subtraction angiography (KEDSA) combined with the tunability of synchrotron beam yields an imaging technique that is highly sensitive to low concentrations of contrast agents. Thus, contrast agent can be administered intravenously, obviating the need for insertion of a guided catheter to deliver a bolus of contrast agent close to the target tissue. With the high-resolution detectors used at synchrotron facilities, images can be acquired at high spatial resolution. Thus, the KEDSA appears particularly suited for studies of neurovascular pathology in animal models, where the vascular diameters are significantly smaller than in human patients. Materials and methods: This feasibility study was designed to test the suitability of KEDSA after intravenous injection of iodine-based contrast agent for use in a pig model. Four adult male pigs were used for our experiments. Neurovascular angiographic images were acquired using KEDSA with a solid state Germanium (Ge) detector at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Results: After intravenous injection of 0.9 ml/kg iodinated contrast agent (Xenetix), the peak iodine concentrations in the internal carotid and middle cerebral arteries reached 35 mg/ml. KEDSA images in radiography mode allowed the visualization of intracranial arteries of less than 1.5 mm diameter.

  9. Synchrotron-based intra-venous K-edge digital subtraction angiography in a pig model: A feasibility study

    International Nuclear Information System (INIS)

    Schueltke, Elisabeth; Fiedler, Stefan; Nemoz, Christian; Ogieglo, Lissa; Kelly, Michael E.; Crawford, Paul; Esteve, Francois; Brochard, Thierry; Renier, Michel; Requardt, Herwig; Le Duc, Geraldine; Juurlink, Bernhard; Meguro, Kotoo

    2010-01-01

    Background: K-edge digital subtraction angiography (KEDSA) combined with the tunability of synchrotron beam yields an imaging technique that is highly sensitive to low concentrations of contrast agents. Thus, contrast agent can be administered intravenously, obviating the need for insertion of a guided catheter to deliver a bolus of contrast agent close to the target tissue. With the high-resolution detectors used at synchrotron facilities, images can be acquired at high spatial resolution. Thus, the KEDSA appears particularly suited for studies of neurovascular pathology in animal models, where the vascular diameters are significantly smaller than in human patients. Materials and methods: This feasibility study was designed to test the suitability of KEDSA after intravenous injection of iodine-based contrast agent for use in a pig model. Four adult male pigs were used for our experiments. Neurovascular angiographic images were acquired using KEDSA with a solid state Germanium (Ge) detector at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Results: After intravenous injection of 0.9 ml/kg iodinated contrast agent (Xenetix), the peak iodine concentrations in the internal carotid and middle cerebral arteries reached 35 mg/ml. KEDSA images in radiography mode allowed the visualization of intracranial arteries of less than 1.5 mm diameter.

  10. Rotational digital subtraction angiography of the renal arteries: technique and evaluation in the study of native and transplant renal arteries.

    Science.gov (United States)

    Seymour, H R; Matson, M B; Belli, A M; Morgan, R; Kyriou, J; Patel, U

    2001-02-01

    Rotational digital subtraction angiography (RDSA) allows multidirectional angiographic acquisitions with a single injection of contrast medium. The role of RDSA was evaluated in 60 patients referred over a 7-month period for diagnostic renal angiography and 12 patients referred for renal transplant studies. All angiograms were assessed for their diagnostic value, the presence of anomalies and the quantity of contrast medium used. The effective dose for native renal RDSA was determined. 41 (68.3%) native renal RDSA images and 8 (66.7%) transplant renal RDSA images were of diagnostic quality. Multiple renal arteries were identified in 9/41 (22%) native renal RDSA diagnostic images. The mean volume of contrast medium in the RDSA runs was 51.2 ml and 50 ml for native and transplant renal studies, respectively. The mean effective dose for 120 degrees native renal RDSA was 2.36 mSv, equivalent to 1 year's mean background radiation. Those RDSA images that were non-diagnostic allowed accurate prediction of the optimal angle for further static angiographic series, which is of great value in transplant renal vessels.

  11. Analysis of differentially expressed genes in two immunologically distinct strains of Eimeria maxima using suppression subtractive hybridization and dot-blot hybridization

    Science.gov (United States)

    2014-01-01

    Background It is well known that different Eimeria maxima strains exhibit significant antigenic variation. However, the genetic basis of these phenotypes remains unclear. Methods Total RNA and mRNA were isolated from unsporulated oocysts of E. maxima strains SH and NT, which were found to have significant differences in immunogenicity in our previous research. Two subtractive cDNA libraries were constructed using suppression subtractive hybridization (SSH) and specific genes were further analyzed by dot-blot hybridization and qRT-PCR analysis. Results A total of 561 clones were selected from both cDNA libraries and the length of the inserted fragments was 0.25–1.0 kb. Dot-blot hybridization revealed a total of 86 differentially expressed clones (63 from strain SH and 23 from strain NT). Nucleotide sequencing analysis of these clones revealed ten specific contigs (six from strain SH and four from strain NT). Further analysis found that six contigs from strain SH and three from strain NT shared significant identities with previously reported proteins, and one contig was presumed to be novel. The specific differentially expressed genes were finally verified by RT-PCR and qRT-PCR analyses. Conclusions The data presented here suggest that specific genes identified between the two strains may be important molecules in the immunogenicity of E. maxima that may present potential new drug targets or vaccine candidates for coccidiosis. PMID:24894832

  12. Utility of time-resolved three-dimensional magnetic resonance digital subtraction angiography without contrast material for assessment of intracranial dural arterio-venous fistula

    International Nuclear Information System (INIS)

    Hori, Masaaki; Aoki, Shigeki; Nakanishi, Atsushi; Shimoji, Keigo; Kamagata, Koji; Houshito, Haruyoshi; Kuwatsuru, Ryohei; Oishi, Hidenori; Arai, Hajime

    2011-01-01

    Background: Intracranial dural arteriovenous fistula (DAVF) is an arteriovenous shunting disease of the dura. Magnetic resonance angiography (MRA) is expected to be a safer alternative method in evaluation of DAVF, compared with invasive intra-arterial digital subtraction angiography (IADSA). Purpose: To evaluate the diagnostic use of time-spatial labeling inversion pulse (Time-SLIP) three-dimensional (3D) magnetic resonance digital subtraction angiography (MRDSA) without contrast material in six patients with DAVF. Material and Methods: Images for 3D time-of-flight MRA, which has been a valuable tool for the diagnosis of DAVF but provide little or less hemodynamic information, and Time-SLIP 3D MRDSA, were acquired for each patient. The presence, side, and grade of the disease were evaluated according to IADSA. Results: In all patients, the presence and side of the DAVF were correctly identified by both 3D time-of-flight MRA and Time-SLIP 3D MRDSA. Cortical reflux present in a patient with a grade 2b DAVF was not detected by Time-SLIP 3D MRDSA, when compared with IADSA findings. Conclusion: Time-SLIP 3D MRDSA provides hemodynamic information without contrast material and is a useful complementary tool for diagnosis of DAVF

  13. Robust design optimization using the price of robustness, robust least squares and regularization methods

    Science.gov (United States)

    Bukhari, Hassan J.

    2017-12-01

    In this paper a framework for robust optimization of mechanical design problems and process systems that have parametric uncertainty is presented using three different approaches. Robust optimization problems are formulated so that the optimal solution is robust which means it is minimally sensitive to any perturbations in parameters. The first method uses the price of robustness approach which assumes the uncertain parameters to be symmetric and bounded. The robustness for the design can be controlled by limiting the parameters that can perturb.The second method uses the robust least squares method to determine the optimal parameters when data itself is subjected to perturbations instead of the parameters. The last method manages uncertainty by restricting the perturbation on parameters to improve sensitivity similar to Tikhonov regularization. The methods are implemented on two sets of problems; one linear and the other non-linear. This methodology will be compared with a prior method using multiple Monte Carlo simulation runs which shows that the approach being presented in this paper results in better performance.

  14. Weighted Low-Rank Approximation of Matrices and Background Modeling

    KAUST Repository

    Dutta, Aritra

    2018-04-15

    We primarily study a special a weighted low-rank approximation of matrices and then apply it to solve the background modeling problem. We propose two algorithms for this purpose: one operates in the batch mode on the entire data and the other one operates in the batch-incremental mode on the data and naturally captures more background variations and computationally more effective. Moreover, we propose a robust technique that learns the background frame indices from the data and does not require any training frames. We demonstrate through extensive experiments that by inserting a simple weight in the Frobenius norm, it can be made robust to the outliers similar to the $\\\\ell_1$ norm. Our methods match or outperform several state-of-the-art online and batch background modeling methods in virtually all quantitative and qualitative measures.

  15. Weighted Low-Rank Approximation of Matrices and Background Modeling

    KAUST Repository

    Dutta, Aritra; Li, Xin; Richtarik, Peter

    2018-01-01

    We primarily study a special a weighted low-rank approximation of matrices and then apply it to solve the background modeling problem. We propose two algorithms for this purpose: one operates in the batch mode on the entire data and the other one operates in the batch-incremental mode on the data and naturally captures more background variations and computationally more effective. Moreover, we propose a robust technique that learns the background frame indices from the data and does not require any training frames. We demonstrate through extensive experiments that by inserting a simple weight in the Frobenius norm, it can be made robust to the outliers similar to the $\\ell_1$ norm. Our methods match or outperform several state-of-the-art online and batch background modeling methods in virtually all quantitative and qualitative measures.

  16. Note on bouncing backgrounds

    Science.gov (United States)

    de Haro, Jaume; Pan, Supriya

    2018-05-01

    The theory of inflation is one of the fundamental and revolutionary developments of modern cosmology that became able to explain many issues of the early Universe in the context of the standard cosmological model (SCM). However, the initial singularity of the Universe, where physics is indefinite, is still obscure in the combined SCM +inflation scenario. An alternative to SCM +inflation without the initial singularity is thus always welcome, and bouncing cosmology is an attempt at that. The current work is thus motivated to investigate the bouncing solutions in modified gravity theories when the background universe is described by the spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) geometry. We show that the simplest way to obtain the bouncing cosmologies in such spacetime is to consider some kind of Lagrangian whose gravitational sector depends only on the square of the Hubble parameter of the FLRW universe. For these modified Lagrangians, the corresponding Friedmann equation, a constraint in the dynamics of the Universe, depicts a curve in the phase space (H ,ρ ), where H is the Hubble parameter and ρ is the energy density of the Universe. As a consequence, a bouncing cosmology is obtained when this curve is closed and crosses the axis H =0 at least twice, and whose simplest particular example is the ellipse depicting the well-known holonomy corrected Friedmann equation in loop quantum cosmology (LQC). Sometimes, a crucial point in such theories is the appearance of the Ostrogradski instability at the perturbative level; however, fortunately enough, in the present work, as long as the linear level of perturbations is concerned, this instability does not appear, although it may appear at the higher order of perturbations.

  17. Suppression subtractive hybridization as a tool to identify anthocyanin metabolism-related genes in apple skin.

    Science.gov (United States)

    Ban, Yusuke; Moriguchi, Takaya

    2010-01-01

    The pigmentation of anthocyanins is one of the important determinants for consumer preference and marketability in horticultural crops such as fruits and flowers. To elucidate the mechanisms underlying the physiological process leading to the pigmentation of anthocyanins, identification of the genes differentially expressed in response to anthocyanin accumulation is a useful strategy. Currently, microarrays have been widely used to isolate differentially expressed genes. However, the use of microarrays is limited by its high cost of special apparatus and materials. Therefore, availability of microarrays is limited and does not come into common use at present. Suppression subtractive hybridization (SSH) is an alternative tool that has been widely used to identify differentially expressed genes due to its easy handling and relatively low cost. This chapter describes the procedures for SSH, including RNA extraction from polysaccharides and polyphenol-rich samples, poly(A)+ RNA purification, evaluation of subtraction efficiency, and differential screening using reverse northern in apple skin.

  18. Digital video subtraction fluorography (DVSF) in the diagnosis of bronchial abnormality associated with congenital heart diseases

    International Nuclear Information System (INIS)

    Sano, Tetsuya; Arisawa, Jun; Nakajima, Toru

    1990-01-01

    To assess bronchial morphology and abnormality, 14 children with congenital heart diseases including 2 postoperative patients (age, 2 m.-4 yr) were studied by digital video subtraction fluorography (DVSF) using digital subtraction and image processing system (Philips, DVI-2). This newly developed technique clearly defined bronchial anatomy in all 14 patients. Bronchial situs could be determined in all 8 patients with complex heart anomalies. Out of 8 patients with respiratory distress in this study, obvious bronchial stenosis or obstruction was found by DVSF in 5 patients. Thus, DVSF image defined anatomies of main and lobar bronchi more clearly than previous noninvasive methods. Moreover, DVSF is noninvasive and easily performed even for small infants and critically ill patients. In conclusion, DVSF may be a useful technique to assess bronchial morphology and abnormality in patients with congenital heart diseases. (author)

  19. Increasing LIGO sensitivity by feedforward subtraction of auxiliary length control noise

    International Nuclear Information System (INIS)

    Meadors, Grant David; Riles, Keith; Kawabe, Keita

    2014-01-01

    LIGO, the Laser Interferometer Gravitational-wave Observatory, has been designed and constructed to measure gravitational wave strain via differential arm length. The LIGO 4 km Michelson arms with Fabry–Perot cavities have auxiliary length control servos for suppressing Michelson motion of the beam-splitter and arm cavity input mirrors, which degrades interferometer sensitivity. We demonstrate how a post facto pipeline improves a data sample from LIGO Science Run 6 with feedforward subtraction. Dividing data into 1024 s windows, we numerically fit filter functions representing the frequency-domain transfer functions from Michelson length channels into the gravitational-wave strain data channel for each window, then subtract the filtered Michelson channel noise (witness) from the strain channel (target). In this paper we describe the algorithm, assess achievable improvements in sensitivity to astrophysical sources, and consider relevance to future interferometry. (paper)

  20. Reduction of Musical Noise in Spectral Subtraction Method Using Subframe Phase Randomization

    Energy Technology Data Exchange (ETDEWEB)

    Seok, J.W.; Bae, K.S. [Kyungpook National University, Taegu (Korea)

    1999-06-01

    The Subframe phase randomization method is applied to the spectral subtraction method to reduce the musical noise in nonvoicing region after speech enhancement. The musical noise in the spectral subtraction method is the result of the narrowband tonal components that appearing somewhat periodically in the spectrogram of unvoiced and silence regions. Thus each synthesis frame in nonvoicing region is divided into several subframes to broaden the narrowband spectrum, and then phases of silence and unvoiced regions are randomized to eliminate the tonal components in the spectrum while keeping the shape of the amplitude spectrum. Performance assessments based on visual inspection of spectrogram, objective measure, and informal subjective listening tests demonstrate the superiority of the proposed algorithm. (author). 7 refs., 5 figs.

  1. THE APPLICATION OF CONTINUOUS WAVELET TRANSFORM BASED FOREGROUND SUBTRACTION METHOD IN 21 cm SKY SURVEYS

    International Nuclear Information System (INIS)

    Gu Junhua; Xu Haiguang; Wang Jingying; Chen Wen; An Tao

    2013-01-01

    We propose a continuous wavelet transform based non-parametric foreground subtraction method for the detection of redshifted 21 cm signal from the epoch of reionization. This method works based on the assumption that the foreground spectra are smooth in frequency domain, while the 21 cm signal spectrum is full of saw-tooth-like structures, thus their characteristic scales are significantly different. We can distinguish them in the wavelet coefficient space easily and perform the foreground subtraction. Compared with the traditional spectral fitting based method, our method is more tolerant to complex foregrounds. Furthermore, we also find that when the instrument has uncorrected response error, our method can also work significantly better than the spectral fitting based method. Our method can obtain similar results with the Wp smoothing method, which is also a non-parametric method, but our method consumes much less computing time

  2. Operator expansions in the minimal subtraction scheme. II. Explicit formulas for coefficient functions

    International Nuclear Information System (INIS)

    Chetyrkin, K.G.

    1989-01-01

    It is shown in an arbitrary model that the coefficient functions of the operator expansion (renormalized in the minimal subtraction scheme) are finite. Explicit formulas convenient for calculating them in practice are obtained. The gluing method and the formalism of the R* operation are used to transform the formulas in such a way that the coefficient functions can be expressed in terms of ordinary diagrams containing neither nonstandard propagators nor an additional loop integration. An important feature of the representation for the coefficient functions is that the R* operation, which subtracts simultaneously the ultraviolet and infrared divergences, guarantees the existence of the coefficient functions in the limit when the dimensional regularization is lifted without any restrictions

  3. Thallium-201 chloride dynamic analysis using thallium-201 chloride and sodium iodide-131 thyroid subtraction scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Morimoto, Setsuo; Hiraki, Yoshio; Togami, Izumi [Okayama Univ. (Japan). School of Medicine

    1984-10-01

    The mechanism of /sup 201/Tl chloride accumulation is unclear in thyroid gland and thyroid tumor. This report examines 108 patients that received thyroid scintigraphy examinations with both /sup 201/Tl chloride and sodium /sup 131/I. The patients were diagnosed clinically and histologically whenever possible. The ROI were obtained by subtraction imaging with both isotopes and by subtraction positive and negative areas of imaging. Dynamic curves were obtained for /sup 201/Tl chloride per square unit of each ROI. The dynamic curve in the radioiodide-accumulated area was examined. The data indicate that the clearance rate of /sup 201/Tl chloride (T/sub 15/) was correlated with the sodium /sup 131/I uptake rate at 24 h (r=0.70).

  4. Venous digital subtraction angiography of the renal arteries in hypertensive patients

    International Nuclear Information System (INIS)

    Brecht, G.; Harder, T.; Franken, T.

    1984-01-01

    We carried out 1890 venous digital subtraction angiograms; this included 113 patients with hypertension in order to exclude renal artery stenosis. On four occasions it was used following surgery on a renal artery. Renal artery stenosis or occlusion was demonstrated in twelve patients, and other vascular diseases or anomalies were found in 24. Two abnormal renal arteries were found following renal artery surgery. The results are compared with smaller groups of patients examined by DSA, and with the results of conventional subtraction methods reported in the literature. In only eight patients (6.8%) DSA provided insufficient information and had to be supplemented by aortography. The method has proved to be a valuable and simple screening method for the investigation of hypertension. (orig.) [de

  5. Magnetization transfer contrast (MTC) and MTC-subtraction: enhancement of cartilage lesions and intracartilaginous degeneration in vitro

    International Nuclear Information System (INIS)

    Vahlensieck, M.; Dombrowski, F.; Leutner, C.; Wagner, U.; Reiser, M.

    1994-01-01

    Human articular cartilage from 16 cadaveric or amputated knees was studied using standard magnetic resonance imaging (MRI), on-resonance magnetization transfer contrast (MTC) and MTC-subtraction MRI. Results were compared with subsequent macroscopic and histopathological findings. MTC-subtraction and T2-weighted spin-echo images visualized cartilaginous surface defects with high sensitivity and specificity. MTC and T2-weighted spin-echo images revealed intra-cartilaginous signal loss without surface defects in 80% of the cases, corresponding to an increased collagen concentration. It is concluded that MTC is sensitive to early cartilage degeneration and MTC-subtraction can be helpful in detecting cartilage defects. (orig.)

  6. Spectral measurements of the cosmic microwave background

    Energy Technology Data Exchange (ETDEWEB)

    Kogut, A.J.

    1989-04-01

    Three experiments have measured the intensity of the Cosmic Microwave Background (CMB) at wavelengths 4.0, 3.0, and 0.21 cm. The measurement at 4.0 cm used a direct-gain total-power radiometer to measure the difference in power between the zenith sky and a large cryogenic reference target. Foreground signals are measured with the same instrument and subtracted from the zenith signal, leaving the CMB as the residual. The reference target consists of a large open-mouth cryostat with a microwave absorber submerged in liquid helium; thin windows block the radiative heat load and prevent condensation atmospheric gases within the cryostat. The thermodynamic temperature of the CMB at 4.0 cm is 2.59 +- 0.07 K. The measurement at 3.0 cm used a superheterodyne Dicke-switched radiometer with a similar reference target to measure the zenith sky temperature. A rotating mirror allowed one of the antenna beams to be redirected to a series of zenith angles, permitting automated atmospheric measurements without moving the radiometer. A weighted average of 5 years of data provided the thermodynamic temperature of the CMB at 3.0 cm of 2.62 +- 0.06 K. The measurement at 0.21 cm used Very Large Array observations of interstellar ortho-formaldehyde to determine the CMB intensity in molecular clouds toward the giant HII region W51A (G49.5-0.4). Solutions of the radiative transfer problem in the context of a large velocity gradient model provided estimates of the CMB temperature within the foreground clouds. Collisional excitation from neutral hydrogen molecules within the clouds limited the precision of the result. The thermodynamic temperature of the CMB at 0.21 cm is 3.2 +- 0.9 K. 72 refs., 27 figs., 38 tabs.

  7. Spectral measurements of the cosmic microwave background

    International Nuclear Information System (INIS)

    Kogut, A.J.

    1989-04-01

    Three experiments have measured the intensity of the Cosmic Microwave Background (CMB) at wavelengths 4.0, 3.0, and 0.21 cm. The measurement at 4.0 cm used a direct-gain total-power radiometer to measure the difference in power between the zenith sky and a large cryogenic reference target. Foreground signals are measured with the same instrument and subtracted from the zenith signal, leaving the CMB as the residual. The reference target consists of a large open-mouth cryostat with a microwave absorber submerged in liquid helium; thin windows block the radiative heat load and prevent condensation atmospheric gases within the cryostat. The thermodynamic temperature of the CMB at 4.0 cm is 2.59 +- 0.07 K. The measurement at 3.0 cm used a superheterodyne Dicke-switched radiometer with a similar reference target to measure the zenith sky temperature. A rotating mirror allowed one of the antenna beams to be redirected to a series of zenith angles, permitting automated atmospheric measurements without moving the radiometer. A weighted average of 5 years of data provided the thermodynamic temperature of the CMB at 3.0 cm of 2.62 +- 0.06 K. The measurement at 0.21 cm used Very Large Array observations of interstellar ortho-formaldehyde to determine the CMB intensity in molecular clouds toward the giant HII region W51A (G49.5-0.4). Solutions of the radiative transfer problem in the context of a large velocity gradient model provided estimates of the CMB temperature within the foreground clouds. Collisional excitation from neutral hydrogen molecules within the clouds limited the precision of the result. The thermodynamic temperature of the CMB at 0.21 cm is 3.2 +- 0.9 K. 72 refs., 27 figs., 38 tabs

  8. Quantitative analysis of alveolar bone change following implant placement using intraoral radiographic subtraction

    International Nuclear Information System (INIS)

    Kimura, Hiroyuki; Kanda, Shigenobu; Tanaka, Takemasa

    2002-01-01

    The purpose of this study was to develop a procedure for quantitative analysis using intraoral radiographs of alveolar bone after placement of dental implants and to consider the validity of the method. We evaluated the ten patients (2 males and 8 females, average age: 48.4 years-old), who were treated with dental implant operation in the site of mandibular molar region, since October of 1999 until September of 2000 in Kimura Dental Clinic (Kumamoto, Japan). We evaluated the intraoral radiographs taken pre- and post- operatively and at follow-up examination. To detect alveolar bone change on radiograph, we adopted the digital subtraction method. Although the radiographs were taken under an ordinary technique with cone indicator, we did not apply the standardized technique with fixing material customized for each patient. Therefore, we used geometric correction and density compensation before subtraction. We assessed the basic statistical values (mean, variance, kurtosis and skewness) of the region of interest (ROI) of the subtracted images. Also, we noted PPD (probing pocket depth) and BOP (bleeding on probing) at each site as indicators of clinical findings and all implanted sites were classified according to the PPD or BOP, i.e. PPD increased group ''PPD (+)'' and PPD stable group ''PPD (-)'', likewise BOP positive group ''BOP (+)'' and negative group ''BOP (-)''. We considered the statistical values of ROI in each group and compared these findings. Mean and variance values of PPD (+) were higher than those of PPD (-) and there was a significant difference in mean value (p=0.031). Similarly, mean and variance values of BOP (+) were statistically higher than those of BOP (-) (p=0.041 and p=0.0087, respectively). Concerning kurtosis and skewness, there was no difference between PPD (+) and PPD (-), or between BOP (+) and BOP (-). Using our method, the radiographs taken for follow-up examination could be assessed quantitatively. It is suggested that geometric

  9. Imaging of the ventricular septal wall and the portal vein by digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Kyoichi; Harashima, Haruhiko; Yamada, Hiromi; Hiraishi, Takahisa; Mikami, Fumio [National Medical Center of Hospital, Tokyo (Japan)

    1983-06-01

    Digital subtraction angiography (DSA) was performed in 2 cases of hypertrophic cardiomyopathy and 2 cases of portal vein disorder. In hypertrophic cardiomyopathy, DSA with the infusion of isopaque 370 at the speed of 5 to 7 ml/sec produced the image of the ventricular septal wall, showing a small ejection fraction. Of portal vein disorders, DSA revealed the portal vein and was helpful in diagnosing tumoral thrombosis of the portal vein in a case of liver carcinoma and portal hypertension.

  10. Intra-arterial digital subtraction angiography in the diagnosis of insulinomas

    International Nuclear Information System (INIS)

    Moulopoulou, A.; Vlahos, L.

    1988-01-01

    Two cases of surgically proved benign insulinoma of the pancreas were correctly localized with intra-arterial digital subtraction angiography (IA-DSA) of the coeliac and the superior mesenteric artery, while the respective dynamic computed tomography (CT) and ultrasound (US) examinations were negative. In a third case of organic hyperinsulinism, IA-DSA, CT and US suggested a pancreatic islet-cell tumor, but the histological examination of the resected suspicious area was that of focal hyperplasia. 17 refs.; 3 figs

  11. Maximal Abelian and Curci-Ferrari gauges in momentum subtraction at three loops

    Science.gov (United States)

    Bell, J. M.; Gracey, J. A.

    2015-12-01

    The vertex structure of QCD fixed in the maximal Abelian gauge (MAG) and Curci-Ferrari gauge is analyzed at two loops at the fully symmetric point for the 3-point functions corresponding to the three momentum subtraction (MOM) renormalization schemes. Consequently, the three-loop renormalization group functions are determined for each of these three schemes in each gauge using properties of the renormalization group equation.

  12. A simple proof of renormalization group equation in the minimal subtraction scheme

    International Nuclear Information System (INIS)

    Chetyrkin, K.G.

    1989-04-01

    We give a simple combinatorial proof of the renormalization group equation in the minimal subtraction scheme. Being mathematically rigorous, the proof avoids both the notorious complexity of techniques using parametric representations of Feynman diagrams and heuristic arguments of usual ''proofs'' calling up bare fields living in the space-time of complex dimension. It also copes easily with the general case of Green functions of arbitrary number of composite fields. (author). 24 refs

  13. Use of the digital subtraction angiography in the study of aortic dissecting aneurisms

    Energy Technology Data Exchange (ETDEWEB)

    Orlacchio, A; Fanucci, E; Pocek, M; Cirillo, F

    1984-01-01

    Authors on the basis of their data discuss the opportunity affered by the digital subtraction angiography (DSA) in the study of the aorta dissecting aneurisms. DSA as a consequence of the image formation and processing techniques allows the optimization of information concerning the reflux kinetics in the true and false lumen and offers a vascular mapping of the body district under study which is enough indicative to the subsequent therapy.

  14. The use of intravenous digital subtraction angiography in evaluating patients with complex congenital heart disease

    International Nuclear Information System (INIS)

    Moodie, D.S.

    1986-01-01

    The author previously described his experience in 450 patients with congenital heart disease using intravenous digital subtraction angiography (DSA) to define cardiac anatomy. He has been impressed by the utility of DSA in the evaluation of patients with congenital heart disease. It is now an integral part of his clinical practice to perform intravenous DSA studies both pre- and postoperatively on an inpatient as well as outpatient basis. This chapter details his DSA experience with complex forms of congenital heart disease

  15. Intraarterial digital subtraction angiography in bronchogenic carcinoma treated with bronchial artery infusion

    International Nuclear Information System (INIS)

    Gao-Jun Teng; Xi-Lei Chai; Guang-Ru Gao; Cheng-Fong Chu; Xian-Guang Zhou; Zhu-Yi Zhang; Ru-Li Xiang

    1991-01-01

    Intra-arterial digital subtraction angiography (IADSA) has been used with advantage for control of the results of bronchial artery infusion of drugs for primarily unresectable bronchogenic carcinoma. The IADSA has been performed as road mapping prior to therapy. Drug treatment has been performed with 4 different regimes, depending on tumour type. Debulking and in some cases complete healing are the results, which are superior to other reported treatments. (author). 7 refs.; 4 figs.; 3 tabs

  16. Continuous-variable measurement-device-independent quantum key distribution with virtual photon subtraction

    Science.gov (United States)

    Zhao, Yijia; Zhang, Yichen; Xu, Bingjie; Yu, Song; Guo, Hong

    2018-04-01

    The method of improving the performance of continuous-variable quantum key distribution protocols by postselection has been recently proposed and verified. In continuous-variable measurement-device-independent quantum key distribution (CV-MDI QKD) protocols, the measurement results are obtained from untrusted third party Charlie. There is still not an effective method of improving CV-MDI QKD by the postselection with untrusted measurement. We propose a method to improve the performance of coherent-state CV-MDI QKD protocol by virtual photon subtraction via non-Gaussian postselection. The non-Gaussian postselection of transmitted data is equivalent to an ideal photon subtraction on the two-mode squeezed vacuum state, which is favorable to enhance the performance of CV-MDI QKD. In CV-MDI QKD protocol with non-Gaussian postselection, two users select their own data independently. We demonstrate that the optimal performance of the renovated CV-MDI QKD protocol is obtained with the transmitted data only selected by Alice. By setting appropriate parameters of the virtual photon subtraction, the secret key rate and tolerable excess noise are both improved at long transmission distance. The method provides an effective optimization scheme for the application of CV-MDI QKD protocols.

  17. The Relationship Between Problem Size and Fixation Patterns During Addition, Subtraction, Multiplication, and Division

    Directory of Open Access Journals (Sweden)

    Evan T. Curtis

    2016-08-01

    Full Text Available Eye-tracking methods have only rarely been used to examine the online cognitive processing that occurs during mental arithmetic on simple arithmetic problems, that is, addition and multiplication problems with single-digit operands (e.g., operands 2 through 9; 2 + 3, 6 x 8 and the inverse subtraction and division problems (e.g., 5 – 3; 48 ÷ 6. Participants (N = 109 solved arithmetic problems from one of the four operations while their eye movements were recorded. We found three unique fixation patterns. During addition and multiplication, participants allocated half of their fixations to the operator and one-quarter to each operand, independent of problem size. The pattern was similar on small subtraction and division problems. However, on large subtraction problems, fixations were distributed approximately evenly across the three stimulus components. On large division problems, over half of the fixations occurred on the left operand, with the rest distributed between the operation sign and the right operand. We discuss the relations between these eye tracking patterns and other research on the differences in processing across arithmetic operations.

  18. Can approximate mental calculation account for operational momentum in addition and subtraction?

    Science.gov (United States)

    Knops, André; Dehaene, Stanislas; Berteletti, Ilaria; Zorzi, Marco

    2014-01-01

    The operational momentum (OM) effect describes a cognitive bias whereby we overestimate the results of mental addition problems while underestimating for subtraction. To test whether the OM emerges from psychophysical characteristics of the mental magnitude representation we measured two basic parameters (Weber fraction and numerical estimation accuracy) characterizing the mental magnitude representation and participants' performance in cross-notational addition and subtraction problems. Although participants were able to solve the cross-notational problems, they consistently chose relatively larger results in addition problems than in subtraction problems, thus replicating and extending previous results. Combining the above measures in a psychophysical model allowed us to partially predict the chosen results. Most crucially, however, we were not able to fully model the OM bias on the basis of these psychophysical parameters. Our results speak against the idea that the OM is due to basic characteristics of the mental magnitude representation. In turn, this might be interpreted as evidence for the assumption that the OM effect is better explained by attentional shifts along the mental magnitude representation during mental calculation.

  19. DESIGN STUDY: INTEGER SUBTRACTION OPERATION TEACHING LEARNING USING MULTIMEDIA IN PRIMARY SCHOOL

    Directory of Open Access Journals (Sweden)

    Rendi Muhammad Aris

    2016-12-01

    Full Text Available This study aims to develop a learning trajectory to help students understand concept of subtraction of integers using multimedia in the fourth grade. This study is thematic integrative learning in Curriculum 2013 PMRI based. The method used is design research consists of three stages; preparing for the experiment, design experiment, retrospective analysis. The studied was conducted on 20 students of grade four SDN 1 Muara Batun, OKI. The activities of students in this study consisted of six learning trajectories. The first activity asks the students to classify heroism and non-heroism acts, summarize, and classify integers and non-integer. The second activity asks the students to answer the questions in the film given. The third activity asks students to count the remaining gravel in the film. The fourth activity asks students to count remaining spent money in the film. The fifth activity invites students to play rubber seeds in the bag. The last activity asks students to answer the questions in the student worksheet. The media used along the learning activities are a ruler, rubber seed, student worksheet, money, gravel, and film. The results indicate that the learning trajectory using multimedia help students understand the concept of integer subtraction integer. Keywords: Subtraction Integer, PMRI, Multimedia DOI: http://dx.doi.org/10.22342/jme.8.1.3233.95-102

  20. Utility of noise addition image made by using water phantom and image addition and subtraction software

    International Nuclear Information System (INIS)

    Watanabe, Ryo; Aoki, Takahiro; Hayano, Mizuho; Ogawa, Masato; Mituzono, Hiroki; Watanabe, Yuka

    2010-01-01

    In optimizing exposures, it is very important to evaluate the impact of image noise on image quality. To realize this, there is a need to evaluate how much image noise will make the subject disease invisible. But generally it is very difficult to shoot images of different quality in a clinical examination. Thus, a method to create a noise addition image by adding the image noise to raw data has been reported. However, this approach requires a special system, so it is difficult to implement in many facilities. We have invented a method to easily create a noise addition image by using the water phantom and image add-subtract software that accompanies the device. To create a noise addition image, first we made a noise image by subtracting the water phantom with different standard deviation (SD). A noise addition image was then created by adding the noise image to the original image. By using this method, a simulation image with intergraded SD can be created from the original. Moreover, the noise frequency component of the created noise addition image is as same as the real image. Thus, the relationship of image quality to SD in the clinical image can be evaluated. Although this method is an easy method of LDSI creation on image data, a noise addition image can be easily created by using image addition and subtraction software and water phantom, and this can be implemented in many facilities. (author)