Pub Date : 1993-10-18DOI: 10.1109/OCEANS.1993.326066
P. Scrimger, D. Henderson, N. Chapman
Describes an experiment carried out to calibrate a very low frequency sound source in deep water using a method similar to that described by Carey et al. (1987). In the experiment, a cw sound signal was recorded as the uncalibrated source was towed past a vertical line array out to ranges of about 3 km. At these close ranges the sound field is dominated by the Lloyd's mirror interference pattern which arises as a result of the interaction between the direct and surface-reflected sound paths. The calibration procedure is based on a comparison of the measured sound field with numerical calculations of the Lloyd's mirror interference field. The experimental track for the towed source was determined using GPS navigation records, and the source-receiver range was checked using the beamforming capability of the array. The signals recorded on a single hydrophone were processed to determine the received sound level versus range, and these data were corrected for the transmission loss using a full-wave numerical model for the sound field. The corrected sound levels provided a measure of the source level of the uncalibrated source. Calibration results are presented for three phones when the source was transmitting at a frequency of 10 Hz with an output voltage of 30 volts.<>
{"title":"Calibration of an underwater sound source at very low frequency","authors":"P. Scrimger, D. Henderson, N. Chapman","doi":"10.1109/OCEANS.1993.326066","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326066","url":null,"abstract":"Describes an experiment carried out to calibrate a very low frequency sound source in deep water using a method similar to that described by Carey et al. (1987). In the experiment, a cw sound signal was recorded as the uncalibrated source was towed past a vertical line array out to ranges of about 3 km. At these close ranges the sound field is dominated by the Lloyd's mirror interference pattern which arises as a result of the interaction between the direct and surface-reflected sound paths. The calibration procedure is based on a comparison of the measured sound field with numerical calculations of the Lloyd's mirror interference field. The experimental track for the towed source was determined using GPS navigation records, and the source-receiver range was checked using the beamforming capability of the array. The signals recorded on a single hydrophone were processed to determine the received sound level versus range, and these data were corrected for the transmission loss using a full-wave numerical model for the sound field. The corrected sound levels provided a measure of the source level of the uncalibrated source. Calibration results are presented for three phones when the source was transmitting at a frequency of 10 Hz with an output voltage of 30 volts.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114303678","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.325956
E. Hammerstad, S. Asheim, K. Nilsen, H. Bodholt
The SIMRAD EM family of multibeam echo sounders are characterized by extremely wide swath widths with up to 190/spl deg/ angular coverage, high accuracy due to interferometric bottom detection, integrated sonar imaging (sidescan), and ease of operation. Continuous improvements of these systems are being made as a result of user experience and new requirements. Examples of requirements which have recently been addressed are the implementation of equidistant horizontal sounding pattern acrosstrack, and the capability of surveying all the way to the water surface along shorelines. Simrad Subsea has in the nineties sold 7 EM 12 deep sea systems, 11 EM 1000 intermediate depth systems, and 4 EM 950 shallow water systems, in addition to the 14 EM 100 systems delivered in the eighties, thus making Simrad the major manufacturer of multibeam echo sounder systems today. As the multibeam echo sounder systems are maturing, the efforts of both users and Simrad are shifting towards getting more out of the data collected, i.e. to improve the postprocessing and to find novel postprocessing methods, especially in the use of the sonar image data. This shift is reflected in this paper with a major part dedicated to the new generation of the Simrad postprocessing systems for multibeam echo sounder data. This includes both real-time processing and postprocessing of the EM echo sounder data to deliver end results such as bathymetry and sonar image visualization, charts, 3D views, sonar image mosaics, and seabed classification.<>
{"title":"Advances in multibeam echo sounder technology","authors":"E. Hammerstad, S. Asheim, K. Nilsen, H. Bodholt","doi":"10.1109/OCEANS.1993.325956","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.325956","url":null,"abstract":"The SIMRAD EM family of multibeam echo sounders are characterized by extremely wide swath widths with up to 190/spl deg/ angular coverage, high accuracy due to interferometric bottom detection, integrated sonar imaging (sidescan), and ease of operation. Continuous improvements of these systems are being made as a result of user experience and new requirements. Examples of requirements which have recently been addressed are the implementation of equidistant horizontal sounding pattern acrosstrack, and the capability of surveying all the way to the water surface along shorelines. Simrad Subsea has in the nineties sold 7 EM 12 deep sea systems, 11 EM 1000 intermediate depth systems, and 4 EM 950 shallow water systems, in addition to the 14 EM 100 systems delivered in the eighties, thus making Simrad the major manufacturer of multibeam echo sounder systems today. As the multibeam echo sounder systems are maturing, the efforts of both users and Simrad are shifting towards getting more out of the data collected, i.e. to improve the postprocessing and to find novel postprocessing methods, especially in the use of the sonar image data. This shift is reflected in this paper with a major part dedicated to the new generation of the Simrad postprocessing systems for multibeam echo sounder data. This includes both real-time processing and postprocessing of the EM echo sounder data to deliver end results such as bathymetry and sonar image visualization, charts, 3D views, sonar image mosaics, and seabed classification.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116786405","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.326104
D. J. Ferkinhoff, C. T. Nguyen, S. Hammel, K. Gong
Artificial neural networks (ANN's) can be exploited in a variety of information processing applications because they offer simplicity of implementation, possess inherent parallel processing characteristics and are nonlinear and less reliant on modeling of the real process. The paper is concerned with the problem of determining the performance of ANN's trained to provide estimates of contact state variables given a time series of measurements. A method is presented for determining ANN performance. Specifically, performance is shown to be intrinsically related to system observability. A performance analysis of ANN's under various observability conditions is presented along with a methodology for selecting the appropriate ANN-generated solution with a system architecture comprised of multiple clusters of ANN's.<>
{"title":"Performance characterization of artificial neural networks for contact tracking","authors":"D. J. Ferkinhoff, C. T. Nguyen, S. Hammel, K. Gong","doi":"10.1109/OCEANS.1993.326104","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326104","url":null,"abstract":"Artificial neural networks (ANN's) can be exploited in a variety of information processing applications because they offer simplicity of implementation, possess inherent parallel processing characteristics and are nonlinear and less reliant on modeling of the real process. The paper is concerned with the problem of determining the performance of ANN's trained to provide estimates of contact state variables given a time series of measurements. A method is presented for determining ANN performance. Specifically, performance is shown to be intrinsically related to system observability. A performance analysis of ANN's under various observability conditions is presented along with a methodology for selecting the appropriate ANN-generated solution with a system architecture comprised of multiple clusters of ANN's.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125822395","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.325963
Y. Stephan, B. Frachon
Presents a neural approach for bathythermogram classification. A modular architecture of multi-layer perceptrons (MLP) stemming from a preclassification into five main types of temperature profile is used. The types and classes are issued from a pre-established typology. The performance of this approach is evaluated on a Red Sea profiles database. The results show that the method is efficient but suffers from classes overlapping.<>
{"title":"A modular neural architecture for bathythermograms classification","authors":"Y. Stephan, B. Frachon","doi":"10.1109/OCEANS.1993.325963","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.325963","url":null,"abstract":"Presents a neural approach for bathythermogram classification. A modular architecture of multi-layer perceptrons (MLP) stemming from a preclassification into five main types of temperature profile is used. The types and classes are issued from a pre-established typology. The performance of this approach is evaluated on a Red Sea profiles database. The results show that the method is efficient but suffers from classes overlapping.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125887121","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.326222
E. Belcher
Swath bathymetry, underwater searches, obstacle avoidance, and navigation are greatly enhanced by a high resolution, multibeam sonar. Acoustic lens technology provides a relatively compact and inexpensive sensor that can transmit and then receive multiple conical or rectangular beams using no beamforming electronics. The paper describes the basic components of a liquid-filled, spherical acoustic lens and provides both theoretical and empirical data which show lens beam patterns and how lens focus changes with temperature. The paper also describes a lens implementation in a compact, multibeam, diver-held sonar.<>
{"title":"A multibeam, diver-held sonar using a liquid-filled, spherical acoustic lens","authors":"E. Belcher","doi":"10.1109/OCEANS.1993.326222","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326222","url":null,"abstract":"Swath bathymetry, underwater searches, obstacle avoidance, and navigation are greatly enhanced by a high resolution, multibeam sonar. Acoustic lens technology provides a relatively compact and inexpensive sensor that can transmit and then receive multiple conical or rectangular beams using no beamforming electronics. The paper describes the basic components of a liquid-filled, spherical acoustic lens and provides both theoretical and empirical data which show lens beam patterns and how lens focus changes with temperature. The paper also describes a lens implementation in a compact, multibeam, diver-held sonar.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"117 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129722948","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.326025
Ji‐xun Zhou, Xue‐zhen Zhang, P. Rogers, Dezhao Wang, Ensheng Luo
At-sea experimental data and numerical simulation results are given to show that, acoustic normal-mode coupling induced by internal solitons could be an important loss mechanism for shallow water sound propagation.<>
海上实验数据和数值模拟结果表明，由内孤子引起的声正模耦合可能是浅水声传播的重要损失机制。
{"title":"Anomalous sound propagation in shallow water due to internal wave solitons","authors":"Ji‐xun Zhou, Xue‐zhen Zhang, P. Rogers, Dezhao Wang, Ensheng Luo","doi":"10.1109/OCEANS.1993.326025","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326025","url":null,"abstract":"At-sea experimental data and numerical simulation results are given to show that, acoustic normal-mode coupling induced by internal solitons could be an important loss mechanism for shallow water sound propagation.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128361429","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.326082
A. Meyer
A 20 kW proton exchange membrane (PEM) fuel cell power plant developed for application in unmanned underwater vehicles (UUVs) is described. The power plant is based on a simple system concept requiring no circulation of gases for thermal and water management-enhancing reliability, durability and maximizing energy density and vehicle range. The power plant is part of an energy storage system designed to replace the silver-zinc battery system currently used to supply power in the 44-inch UUV developed by the United States Advanced Research Projects Agency. The power plant may be operated with hydrogen and oxygen supplied from a variety of alternative sources. Hydrogen generation from methanol by reforming is discussed. Specifically, a method demonstrated for reducing the carbon-monoxide content of reformate to levels compatible with the long endurance of the PEM fuel cell is presented. Data showing compatibility with hydrogen supplied from a regenerable metal hydride bed is also presented.<>
{"title":"Development of proton exchange membrane fuel cells for underwater applications","authors":"A. Meyer","doi":"10.1109/OCEANS.1993.326082","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326082","url":null,"abstract":"A 20 kW proton exchange membrane (PEM) fuel cell power plant developed for application in unmanned underwater vehicles (UUVs) is described. The power plant is based on a simple system concept requiring no circulation of gases for thermal and water management-enhancing reliability, durability and maximizing energy density and vehicle range. The power plant is part of an energy storage system designed to replace the silver-zinc battery system currently used to supply power in the 44-inch UUV developed by the United States Advanced Research Projects Agency. The power plant may be operated with hydrogen and oxygen supplied from a variety of alternative sources. Hydrogen generation from methanol by reforming is discussed. Specifically, a method demonstrated for reducing the carbon-monoxide content of reformate to levels compatible with the long endurance of the PEM fuel cell is presented. Data showing compatibility with hydrogen supplied from a regenerable metal hydride bed is also presented.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129629015","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.326177
P. Hendricks
A procedure for calculating ocean currents from submarine set and drift is described. Relationships for the response length of the submarine to velocity perturbations are given. These lengths are found to be 3-10 boat lengths, and they represent a limit to the spatial resolution of the current measurements. A procedure for the in-situ calibration of the submarine speed sensor is described. An example shows that the current vectors are consistent from one leg of the submarine track to another and with satellite observations. Ocean current measurement capability is presently being integrated into an oceanographic monitoring system for tactical applications.<>
{"title":"Ocean current measurements from submarine set and drift","authors":"P. Hendricks","doi":"10.1109/OCEANS.1993.326177","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326177","url":null,"abstract":"A procedure for calculating ocean currents from submarine set and drift is described. Relationships for the response length of the submarine to velocity perturbations are given. These lengths are found to be 3-10 boat lengths, and they represent a limit to the spatial resolution of the current measurements. A procedure for the in-situ calibration of the submarine speed sensor is described. An example shows that the current vectors are consistent from one leg of the submarine track to another and with satellite observations. Ocean current measurement capability is presently being integrated into an oceanographic monitoring system for tactical applications.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"07 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128958880","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.326236
A. Wright
The advantages of collecting seafloor imagery and bathymetry from a deep towed full ocean depth sidescan sonar system are becoming widely appreciated. The number of systems in active use in the scientific, government and commercial communities has more than doubled in the last five years. New improvements include multi-frequency, chirp, integral swath bathymetry, fiber-optic cable, improved speeds and greatly improved image processing. Countries with organizations operating these sonars include the United States, the United Kingdom, Russia and France. This paper describes the operating procedures for deep towed sidescan sonars, briefly describes and compares the various systems, and discusses the new improvements. The major operations for some of the systems are highlighted and emerging market areas explored.<>
{"title":"Deep towed sidescan sonars","authors":"A. Wright","doi":"10.1109/OCEANS.1993.326236","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326236","url":null,"abstract":"The advantages of collecting seafloor imagery and bathymetry from a deep towed full ocean depth sidescan sonar system are becoming widely appreciated. The number of systems in active use in the scientific, government and commercial communities has more than doubled in the last five years. New improvements include multi-frequency, chirp, integral swath bathymetry, fiber-optic cable, improved speeds and greatly improved image processing. Countries with organizations operating these sonars include the United States, the United Kingdom, Russia and France. This paper describes the operating procedures for deep towed sidescan sonars, briefly describes and compares the various systems, and discusses the new improvements. The major operations for some of the systems are highlighted and emerging market areas explored.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130664434","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.325971
D. Clapp
As part of a University of Rhode Island Ocean Technology program promoting university/industry cooperation, graduate students in ocean engineering undertook the preliminary design and implementation of an inexpensive data collection and real-time mosaicing system for use with dual frequency side-scan sonar tow fish. Objectives for the design included replacing high-cost deck units and mini-computer acquisition systems with a receiver integrated into a personal computer using a single printed circuit board with an external high voltage power supply box. Hardware features on the new system are described. Software features include: (1) real-time scrolling of side-scan data, (2) display of navigation and control data (3) real-time bottom detect and mosaicing of data, and (4) data logging. The hardware system used for initial development consists of a 33 MHz 386 PC/AT bus computer, a SVGA display card and monitor with resolution up to 1024/spl times/768/spl times/256 colors, and a SCSI disk and tape. A 16-bit AT prototype board contains all the necessary digital and analog components for data acquisition. An external 750 volt power supply provides system compatibility with EG&G and Klein tow fish. Digitized sonar returns are acquired via 4096 byte FIFO data buffers and Direct Memory Access (DMA) for data rates of 40 kilobytes per second. Standard I/O port addressing is used for input from control knobs and communications to the board. A preliminary bottom detect and mosaicing system for display has been prototyped using software in the PC and a Spectrum TMS320C30 DSP card in the 386 computer.<>
{"title":"A modern PC-based sidescan sonar acquisition and display system","authors":"D. Clapp","doi":"10.1109/OCEANS.1993.325971","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.325971","url":null,"abstract":"As part of a University of Rhode Island Ocean Technology program promoting university/industry cooperation, graduate students in ocean engineering undertook the preliminary design and implementation of an inexpensive data collection and real-time mosaicing system for use with dual frequency side-scan sonar tow fish. Objectives for the design included replacing high-cost deck units and mini-computer acquisition systems with a receiver integrated into a personal computer using a single printed circuit board with an external high voltage power supply box. Hardware features on the new system are described. Software features include: (1) real-time scrolling of side-scan data, (2) display of navigation and control data (3) real-time bottom detect and mosaicing of data, and (4) data logging. The hardware system used for initial development consists of a 33 MHz 386 PC/AT bus computer, a SVGA display card and monitor with resolution up to 1024/spl times/768/spl times/256 colors, and a SCSI disk and tape. A 16-bit AT prototype board contains all the necessary digital and analog components for data acquisition. An external 750 volt power supply provides system compatibility with EG&G and Klein tow fish. Digitized sonar returns are acquired via 4096 byte FIFO data buffers and Direct Memory Access (DMA) for data rates of 40 kilobytes per second. Standard I/O port addressing is used for input from control knobs and communications to the board. A preliminary bottom detect and mosaicing system for display has been prototyped using software in the PC and a Spectrum TMS320C30 DSP card in the 386 computer.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127956368","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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