Pub Date : 1992-10-25DOI: 10.1109/NSSMIC.1992.301049
G. Chinn, S. Huang
Images reconstructed by Bayesian and maximum-likelihood (ML) using a Gibbs prior with prior weight beta were compared to images produced by filtered backpropagation (FBP) from sinogram data simulated with different counts and image configurations, Bayesian images were generated by the OSL algorithm accelerated by an overrelaxation parameter and modified by a simple averaging procedure to dampen instabilities caused by acceleration. For relatively low beta , Bayesian images can yield an overall improvement of the images compared to ML. However, for larger beta , Bayesian images degrade from the standpoint of noise and quantitation. Compared to FBP, the ML images were superior in a mean-square error sense in regions of low activity level and for small structures. Bayesian reconstruction can recover resolution without sacrificing noise performance and is dependent on the image structure and the weight of the Bayesian prior.<>
{"title":"Noise and resolution of Bayesian reconstruction for multiple image configurations","authors":"G. Chinn, S. Huang","doi":"10.1109/NSSMIC.1992.301049","DOIUrl":"https://doi.org/10.1109/NSSMIC.1992.301049","url":null,"abstract":"Images reconstructed by Bayesian and maximum-likelihood (ML) using a Gibbs prior with prior weight beta were compared to images produced by filtered backpropagation (FBP) from sinogram data simulated with different counts and image configurations, Bayesian images were generated by the OSL algorithm accelerated by an overrelaxation parameter and modified by a simple averaging procedure to dampen instabilities caused by acceleration. For relatively low beta , Bayesian images can yield an overall improvement of the images compared to ML. However, for larger beta , Bayesian images degrade from the standpoint of noise and quantitation. Compared to FBP, the ML images were superior in a mean-square error sense in regions of low activity level and for small structures. Bayesian reconstruction can recover resolution without sacrificing noise performance and is dependent on the image structure and the weight of the Bayesian prior.<<ETX>>","PeriodicalId":447239,"journal":{"name":"IEEE Conference on Nuclear Science Symposium and Medical Imaging","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127270213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-25DOI: 10.1109/NSSMIC.1992.301281
C. Alippi, G. Appelquist, S. Berglund, C. Bohm, L. Breveglieri, S. Brigati, P. Carlson, P. Cattaneo, L. Dadda, A. Dell'Acqua, C. Fuglesang, G. Fumagalli, U. Gatti, V. Goggi, M. Hansen, H. Hentzell, A. Kerek, B. Lofstedt, F. Maloberti, V. Piuri, F. Salice, M. Sami, R. Stefanelli, R. Sundblad, C. SveNSSMICon, G. Torelli, J. Vanuxem, N. Yamdagni, J. Yuan
The authors present a digital solution to the front-end electronics for calorimetric detectors at future supercolliders based on high-speed analog-to-digital converters, a fully programmable pipeline/digital filter chain, and local intelligence. Questions of error correction, fault-tolerance, and system redundancy are also considered. A system integration of a multichannel device in a multichip, silicon-on-silicon microsystem hybrid will be used. This solution allows a new level of integration of complex analog and digital functions, with excellent flexibility in mixing technologies for the different functional blocks. This type of VLSI multichip integration allows a high degree of programmability at both the function and the system level, and offers the possibility of customizing the microsystem with detector-specific functions.<>
{"title":"A digital front-end readout microsystem for calorimetry at LHC-the FERMI Project","authors":"C. Alippi, G. Appelquist, S. Berglund, C. Bohm, L. Breveglieri, S. Brigati, P. Carlson, P. Cattaneo, L. Dadda, A. Dell'Acqua, C. Fuglesang, G. Fumagalli, U. Gatti, V. Goggi, M. Hansen, H. Hentzell, A. Kerek, B. Lofstedt, F. Maloberti, V. Piuri, F. Salice, M. Sami, R. Stefanelli, R. Sundblad, C. SveNSSMICon, G. Torelli, J. Vanuxem, N. Yamdagni, J. Yuan","doi":"10.1109/NSSMIC.1992.301281","DOIUrl":"https://doi.org/10.1109/NSSMIC.1992.301281","url":null,"abstract":"The authors present a digital solution to the front-end electronics for calorimetric detectors at future supercolliders based on high-speed analog-to-digital converters, a fully programmable pipeline/digital filter chain, and local intelligence. Questions of error correction, fault-tolerance, and system redundancy are also considered. A system integration of a multichannel device in a multichip, silicon-on-silicon microsystem hybrid will be used. This solution allows a new level of integration of complex analog and digital functions, with excellent flexibility in mixing technologies for the different functional blocks. This type of VLSI multichip integration allows a high degree of programmability at both the function and the system level, and offers the possibility of customizing the microsystem with detector-specific functions.<<ETX>>","PeriodicalId":447239,"journal":{"name":"IEEE Conference on Nuclear Science Symposium and Medical Imaging","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127346261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-25DOI: 10.1109/NSSMIC.1992.301311
D. C. Hensley
Summary form only given. The Apnea Unit, an active-passive neutron examination and assay unit, extends the traditional differential dieaway technique for the nondestructive assay of transuranic waste. A key aspect of the new capabilities of this device is the novel approach to the data acquisition. The unit currently gives individual support to over 80 /sup 3/He gas proportional tubes for neutron detection and maintains a detailed list-mode time history for each detector. The CAMAC-based data acquisition system centers on a multi-time tagging module which records detector hits and their associated time. The data are managed in a CAMAC crate by an event handler which services the time tagging modules and blocks the resulting data through a FIFO into a personal computer. The richness of the resulting data is already being used to profile the contents of an assay drum and to differentiate events associated with cosmic rays.<>
{"title":"CAMAC-based data acquisition for the Apnea Unit","authors":"D. C. Hensley","doi":"10.1109/NSSMIC.1992.301311","DOIUrl":"https://doi.org/10.1109/NSSMIC.1992.301311","url":null,"abstract":"Summary form only given. The Apnea Unit, an active-passive neutron examination and assay unit, extends the traditional differential dieaway technique for the nondestructive assay of transuranic waste. A key aspect of the new capabilities of this device is the novel approach to the data acquisition. The unit currently gives individual support to over 80 /sup 3/He gas proportional tubes for neutron detection and maintains a detailed list-mode time history for each detector. The CAMAC-based data acquisition system centers on a multi-time tagging module which records detector hits and their associated time. The data are managed in a CAMAC crate by an event handler which services the time tagging modules and blocks the resulting data through a FIFO into a personal computer. The richness of the resulting data is already being used to profile the contents of an assay drum and to differentiate events associated with cosmic rays.<<ETX>>","PeriodicalId":447239,"journal":{"name":"IEEE Conference on Nuclear Science Symposium and Medical Imaging","volume":"19 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132152869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-25DOI: 10.1109/NSSMIC.1992.301295
J. M. Rochelle, M. L. Simpson
A novel time-to-amplitude converter (TAC) topology is presented that allows the conversion of time durations down to and including zero. The stability of this circuit depends only on the matching of two DC current sources. Over a 16 ns full-scale range the integral nonlinearity of this circuit was <+or-0.15%; the differential nonlinearity was <+or-2% over the top half of the range and <+or-6% over the bottom half of the range.<>
{"title":"Current-mode time-to-amplitude converter for precision sub-nanosecond measurement","authors":"J. M. Rochelle, M. L. Simpson","doi":"10.1109/NSSMIC.1992.301295","DOIUrl":"https://doi.org/10.1109/NSSMIC.1992.301295","url":null,"abstract":"A novel time-to-amplitude converter (TAC) topology is presented that allows the conversion of time durations down to and including zero. The stability of this circuit depends only on the matching of two DC current sources. Over a 16 ns full-scale range the integral nonlinearity of this circuit was <+or-0.15%; the differential nonlinearity was <+or-2% over the top half of the range and <+or-6% over the bottom half of the range.<<ETX>>","PeriodicalId":447239,"journal":{"name":"IEEE Conference on Nuclear Science Symposium and Medical Imaging","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130876146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-25DOI: 10.1109/NSSMIC.1992.301391
Y. Fujii, D. Wehe, T.E. Weymouth, J. Borenstein
An approach to developing more capable mobile robots through integrating robotics R&D with advanced reactor design is presented. The GE ALMR (Advanced Liquid Metal Reactor) design is used as the focus for defining the mobile robotic R&D being performed in the areas of locomotion, sensing, manipulation, navigation, machine intelligence, and man-machine shared control.<>
{"title":"Mobile robotics in future nuclear reactor environments","authors":"Y. Fujii, D. Wehe, T.E. Weymouth, J. Borenstein","doi":"10.1109/NSSMIC.1992.301391","DOIUrl":"https://doi.org/10.1109/NSSMIC.1992.301391","url":null,"abstract":"An approach to developing more capable mobile robots through integrating robotics R&D with advanced reactor design is presented. The GE ALMR (Advanced Liquid Metal Reactor) design is used as the focus for defining the mobile robotic R&D being performed in the areas of locomotion, sensing, manipulation, navigation, machine intelligence, and man-machine shared control.<<ETX>>","PeriodicalId":447239,"journal":{"name":"IEEE Conference on Nuclear Science Symposium and Medical Imaging","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130898299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-25DOI: 10.1109/NSSMIC.1992.301183
J. Lund, F. Olschner
The use of junction field effect transistors (JFETs) as radiation detectors is described. Measurements of the energy resolution of n-channel JFETs operated as X-ray spectrometers are presented. An energy resolution of 210 eV FWHM at 5.9 keV was obtained at room temperature using a commercially available JFET as a detector. An analysis of the behavior of JFETs as X-ray spectrometers is presented together with suggestions on designing future devices specifically for use as radiation detectors. It is concluded that detectors approaching the performance of cooled Si(Li) detectors but capable of operating at room temperature could be made from JFETs.<>
介绍了结场效应晶体管(jfet)作为辐射探测器的应用。介绍了用x射线光谱仪测量n沟道jfet能量分辨率的方法。利用市售的JFET作为探测器，在室温下获得了5.9 keV下210 eV FWHM的能量分辨率。对jfet作为x射线光谱仪的性能进行了分析，并对未来设计专门用作辐射探测器的器件提出了建议。研究结果表明，利用jfet可以制备出性能接近冷却型Si(Li)探测器但又能在室温下工作的探测器
{"title":"Junction field effect transistors as radiation detectors","authors":"J. Lund, F. Olschner","doi":"10.1109/NSSMIC.1992.301183","DOIUrl":"https://doi.org/10.1109/NSSMIC.1992.301183","url":null,"abstract":"The use of junction field effect transistors (JFETs) as radiation detectors is described. Measurements of the energy resolution of n-channel JFETs operated as X-ray spectrometers are presented. An energy resolution of 210 eV FWHM at 5.9 keV was obtained at room temperature using a commercially available JFET as a detector. An analysis of the behavior of JFETs as X-ray spectrometers is presented together with suggestions on designing future devices specifically for use as radiation detectors. It is concluded that detectors approaching the performance of cooled Si(Li) detectors but capable of operating at room temperature could be made from JFETs.<<ETX>>","PeriodicalId":447239,"journal":{"name":"IEEE Conference on Nuclear Science Symposium and Medical Imaging","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130387992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-25DOI: 10.1109/NSSMIC.1992.301098
M. Daube-Witherspoon, R. Carson, Y. Yan, T. K. Yap
To obtain quantitative PET (positron emission tomography) images with the ML (maximum likelihood) reconstruction algorithm, the authors investigated the inclusion of a correction for scatter. They implemented the spatially variant convolution method of M. Bergstrom et al. (J. Comput. Assist. Tomogr., vol.7, p.42-50, 1983) which assumes that scatter is independent of depth and collapses the problem to a projection-by-projection scatter model. The model was implemented in three ways: subtraction of scatter estimated from measured projections prior to reconstruction; inclusion of a scatter estimate from the measured projection data in the iteration loop; and inclusion of a scatter estimate in the iteration loop, based on the previous iteration's estimate of trues from the image. The reconstructions were performed on an Intel iPSC/860 hypercube computer. Analysis of the convergence, bias, and noise properties of the three methods of scatter correction demonstrated only slight differences between the methods for real phantom data taken on the Scanditronix PC2048-15B brain PET scanner. The structure of this ML algorithm permits direct extension to a more comprehensive model of scatter.<>
{"title":"Scatter correction in maximum-likelihood reconstruction of PET data","authors":"M. Daube-Witherspoon, R. Carson, Y. Yan, T. K. Yap","doi":"10.1109/NSSMIC.1992.301098","DOIUrl":"https://doi.org/10.1109/NSSMIC.1992.301098","url":null,"abstract":"To obtain quantitative PET (positron emission tomography) images with the ML (maximum likelihood) reconstruction algorithm, the authors investigated the inclusion of a correction for scatter. They implemented the spatially variant convolution method of M. Bergstrom et al. (J. Comput. Assist. Tomogr., vol.7, p.42-50, 1983) which assumes that scatter is independent of depth and collapses the problem to a projection-by-projection scatter model. The model was implemented in three ways: subtraction of scatter estimated from measured projections prior to reconstruction; inclusion of a scatter estimate from the measured projection data in the iteration loop; and inclusion of a scatter estimate in the iteration loop, based on the previous iteration's estimate of trues from the image. The reconstructions were performed on an Intel iPSC/860 hypercube computer. Analysis of the convergence, bias, and noise properties of the three methods of scatter correction demonstrated only slight differences between the methods for real phantom data taken on the Scanditronix PC2048-15B brain PET scanner. The structure of this ML algorithm permits direct extension to a more comprehensive model of scatter.<<ETX>>","PeriodicalId":447239,"journal":{"name":"IEEE Conference on Nuclear Science Symposium and Medical Imaging","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130437613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-25DOI: 10.1109/NSSMIC.1992.301347
I. Barnett, G. Benincasa, O. Berrig, R. Brun, P. Burla, G. Coudert, J. Pett, R. Pittin, J. Royer, N. Trofimov
The CERN Control Protocols provide, for a class of similar devices, a unique and standard access procedure from the control system. Behavioral models have been proposed for the different kinds of power converters, and the corresponding functionalities, with their parameters, variables and attributes, have been identified. The resulting data structures have been presented using the ISO ASN.1 metalanguage, which permits universal representation independent of any computer environment. Implementations in the UNIX-based CERN accelerator control systems are under development. A description of the implementation phase as it is presently being developed at CERN in a cluster of 120 power converters is presented.<>
{"title":"The CERN control protocol for power converters","authors":"I. Barnett, G. Benincasa, O. Berrig, R. Brun, P. Burla, G. Coudert, J. Pett, R. Pittin, J. Royer, N. Trofimov","doi":"10.1109/NSSMIC.1992.301347","DOIUrl":"https://doi.org/10.1109/NSSMIC.1992.301347","url":null,"abstract":"The CERN Control Protocols provide, for a class of similar devices, a unique and standard access procedure from the control system. Behavioral models have been proposed for the different kinds of power converters, and the corresponding functionalities, with their parameters, variables and attributes, have been identified. The resulting data structures have been presented using the ISO ASN.1 metalanguage, which permits universal representation independent of any computer environment. Implementations in the UNIX-based CERN accelerator control systems are under development. A description of the implementation phase as it is presently being developed at CERN in a cluster of 120 power converters is presented.<<ETX>>","PeriodicalId":447239,"journal":{"name":"IEEE Conference on Nuclear Science Symposium and Medical Imaging","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127946118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-25DOI: 10.1109/NSSMIC.1992.301445
G. Stimpfl-Abele
The task of finding decays of charged tracks inside a tracking device is divided into two parts. First, a neural network is used to recognize kinks in well-constructed tracks. The inputs to this classification network are the residuals and the curvature obtained by a one-track fit. If a kink has been found, the same inputs are fed into a second neural network, which gives the radial position of the decay vertex. Both algorithms use feedforward nets with error backpropagation. Very good performance is found in comparison with conventional methods.<>
{"title":"Kink recognition with neural networks","authors":"G. Stimpfl-Abele","doi":"10.1109/NSSMIC.1992.301445","DOIUrl":"https://doi.org/10.1109/NSSMIC.1992.301445","url":null,"abstract":"The task of finding decays of charged tracks inside a tracking device is divided into two parts. First, a neural network is used to recognize kinks in well-constructed tracks. The inputs to this classification network are the residuals and the curvature obtained by a one-track fit. If a kink has been found, the same inputs are fed into a second neural network, which gives the radial position of the decay vertex. Both algorithms use feedforward nets with error backpropagation. Very good performance is found in comparison with conventional methods.<<ETX>>","PeriodicalId":447239,"journal":{"name":"IEEE Conference on Nuclear Science Symposium and Medical Imaging","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129192386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-25DOI: 10.1109/NSSMIC.1992.301462
Soo Chin Liew, C. F. Ku, B. H. Hasegawa
Computer simulations were performed to investigate the effects of the photon noise in radionuclide projection data and the uncertainty in the attenuation map on the image noise in attenuation-corrected SPECT (single photon emission computed tomography) images reconstructed using a maximum-likelihood expectation-maximization algorithm. Simulated radionuclide projection data from a head phantom were acquired using a fan-beam geometry consistent with the emission-transmission (ETCT) system being developed at the University of California at San Francisco. The mean ( mu ) of the reconstructed pixel values in the region of interest started to converge after 10 iterations and the standard deviation ( sigma ) increased with the number of iterations. The sigma / mu ratio was found to be inversely proportional to the square root of the total detected counts and proportional to the relative uncertainty in the attenuation maps. These two noise components contributed independently towards the noise in the reconstructed image. In a typical ETCT system employing an X-ray tube for attenuation map acquisition, the uncertainty in the reconstructed radionuclide distribution would be limited mainly by photon noise in the projection data.<>
{"title":"Noise propagation in SPECT images reconstructed using an iterative maximum-likelihood algorithm","authors":"Soo Chin Liew, C. F. Ku, B. H. Hasegawa","doi":"10.1109/NSSMIC.1992.301462","DOIUrl":"https://doi.org/10.1109/NSSMIC.1992.301462","url":null,"abstract":"Computer simulations were performed to investigate the effects of the photon noise in radionuclide projection data and the uncertainty in the attenuation map on the image noise in attenuation-corrected SPECT (single photon emission computed tomography) images reconstructed using a maximum-likelihood expectation-maximization algorithm. Simulated radionuclide projection data from a head phantom were acquired using a fan-beam geometry consistent with the emission-transmission (ETCT) system being developed at the University of California at San Francisco. The mean ( mu ) of the reconstructed pixel values in the region of interest started to converge after 10 iterations and the standard deviation ( sigma ) increased with the number of iterations. The sigma / mu ratio was found to be inversely proportional to the square root of the total detected counts and proportional to the relative uncertainty in the attenuation maps. These two noise components contributed independently towards the noise in the reconstructed image. In a typical ETCT system employing an X-ray tube for attenuation map acquisition, the uncertainty in the reconstructed radionuclide distribution would be limited mainly by photon noise in the projection data.<<ETX>>","PeriodicalId":447239,"journal":{"name":"IEEE Conference on Nuclear Science Symposium and Medical Imaging","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129285074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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