Pub Date : 2012-08-09DOI: 10.1109/MIM.2012.6263978
C. Parkey, C. Hughes, Nicholas Locken
Wire integrity is a growing concern with aging vehicles, especially high vibration variants like helicopters, tiltrotor aircraft, and many mobile ground weapons systems. Wiring failures on these systems present a growing safety concern and can lead to loss of equipment and life. This paper presents a novel adaptive Time Domain Reflectometry (TDR) algorithm to analyze artifacts found on the reflected time domain waveform of a high-voltage, low-energy pulse transmitted down wires with uncontrolled or controlled impedances. This method allows for detection of intermittent and hard faults. Most Time Domain Reflectometers (TDRs) are used to measure cable lengths and distances to hard opens or shorts. An existing technology, for which this algorithm was developed, extended the measurement capability to intermittent faults. Current detection methods for intermittent faults require an experienced engineer to interpret the returned measurement and waveform to confirm its accuracy. In order to make this technology more accessible the repeatability and accuracy of the automated measurements need to be improved. The following method improves the unadjusted accuracy by 3 times. This paper reviews the theory of TDR and presents implementation and results of the proposed algorithm on real-world data.
{"title":"Analyzing artifacts in the time domain waveform to locate wire faults","authors":"C. Parkey, C. Hughes, Nicholas Locken","doi":"10.1109/MIM.2012.6263978","DOIUrl":"https://doi.org/10.1109/MIM.2012.6263978","url":null,"abstract":"Wire integrity is a growing concern with aging vehicles, especially high vibration variants like helicopters, tiltrotor aircraft, and many mobile ground weapons systems. Wiring failures on these systems present a growing safety concern and can lead to loss of equipment and life. This paper presents a novel adaptive Time Domain Reflectometry (TDR) algorithm to analyze artifacts found on the reflected time domain waveform of a high-voltage, low-energy pulse transmitted down wires with uncontrolled or controlled impedances. This method allows for detection of intermittent and hard faults. Most Time Domain Reflectometers (TDRs) are used to measure cable lengths and distances to hard opens or shorts. An existing technology, for which this algorithm was developed, extended the measurement capability to intermittent faults. Current detection methods for intermittent faults require an experienced engineer to interpret the returned measurement and waveform to confirm its accuracy. In order to make this technology more accessible the repeatability and accuracy of the automated measurements need to be improved. The following method improves the unadjusted accuracy by 3 times. This paper reviews the theory of TDR and presents implementation and results of the proposed algorithm on real-world data.","PeriodicalId":110721,"journal":{"name":"2011 IEEE AUTOTESTCON","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131040088","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 : 2011-10-24DOI: 10.1109/AUTEST.2011.6058757
T. Sarfi
The system switch plays a crucial role in any automated test system as it provides ATE engineers the ability to distribute a finite amount of instrumentation I/O to multiple test points. The popularity of modular architectures such as VXI and PXI, created an opportunity for consolidation of instrumentation and switching within a single mainframe, resulting in high-channel count capability in a reduced footprint. A modular approach to switching systems also affords the ATE architect design flexibility through the use of domain-specific modules (i.e, power, RF, and analog) that can be combined to cover a broad range of the signal spectrum. Unfortunately, software development and integration can become unnecessarily complicated when the system switch is viewed simply as a collection of discrete modules that are assembled to accommodate the required I/O count. This paper will discuss web-based methodologies and software platforms that VTI Instruments has developed to create a versatile system-level switching programming environment. This framework, which is implemented on web-enabled LXI-based modular switch instruments, significantly reduces test program set development time and simplifies debugging and design validation activities without the overhead of third party configuration tools.
{"title":"A system-level approach to designing modular switching software","authors":"T. Sarfi","doi":"10.1109/AUTEST.2011.6058757","DOIUrl":"https://doi.org/10.1109/AUTEST.2011.6058757","url":null,"abstract":"The system switch plays a crucial role in any automated test system as it provides ATE engineers the ability to distribute a finite amount of instrumentation I/O to multiple test points. The popularity of modular architectures such as VXI and PXI, created an opportunity for consolidation of instrumentation and switching within a single mainframe, resulting in high-channel count capability in a reduced footprint. A modular approach to switching systems also affords the ATE architect design flexibility through the use of domain-specific modules (i.e, power, RF, and analog) that can be combined to cover a broad range of the signal spectrum. Unfortunately, software development and integration can become unnecessarily complicated when the system switch is viewed simply as a collection of discrete modules that are assembled to accommodate the required I/O count. This paper will discuss web-based methodologies and software platforms that VTI Instruments has developed to create a versatile system-level switching programming environment. This framework, which is implemented on web-enabled LXI-based modular switch instruments, significantly reduces test program set development time and simplifies debugging and design validation activities without the overhead of third party configuration tools.","PeriodicalId":110721,"journal":{"name":"2011 IEEE AUTOTESTCON","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121398889","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 : 2011-10-24DOI: 10.1109/AUTEST.2011.6058770
L. Segal
The Johns Hopkins University Applied Physics Laboratory (APL) has developed numerous spacecraft for national security and civilian space applications that have used varied flight computers and ground control systems. On missions that have utilized different ground control systems, the command and telemetry (C&T) database development has been unique to the specific mission. On missions that have utilized a common ground control system, APL has leveraged a limited extent of commonality in the development of the C&T databases, which has shown promise in development, schedule, and cost efficiency and has improved the quality of the early C&T database deliveries. On its recent Radiation Belt Storm Probes mission (RBSP), APL developed a set of C&T tools to tackle the challenge of developing a common C&T database across multiple satellites, over full mission life cycles, that minimizes coupling with the core ground control system such that the use across different ground systems is maximized. This paper discusses the specific approach taken in evaluating the C&T database development for APL's past missions and the shortfalls that were encountered. Lessons learned were evaluated and decisions were made in implementing the RBSP C&T databases. The tool development is briefly discussed with an emphasis on the engineering use during satellite subsystem development. Recent successes during the testing are also presented. Finally, plans are described for continued improvement to the approach and tools for subsequent APL spacecraft so that the C&T database can be ported to other missions of interest.
{"title":"Development of a command and telemetry processing interface to be independent of ground control systems","authors":"L. Segal","doi":"10.1109/AUTEST.2011.6058770","DOIUrl":"https://doi.org/10.1109/AUTEST.2011.6058770","url":null,"abstract":"The Johns Hopkins University Applied Physics Laboratory (APL) has developed numerous spacecraft for national security and civilian space applications that have used varied flight computers and ground control systems. On missions that have utilized different ground control systems, the command and telemetry (C&T) database development has been unique to the specific mission. On missions that have utilized a common ground control system, APL has leveraged a limited extent of commonality in the development of the C&T databases, which has shown promise in development, schedule, and cost efficiency and has improved the quality of the early C&T database deliveries. On its recent Radiation Belt Storm Probes mission (RBSP), APL developed a set of C&T tools to tackle the challenge of developing a common C&T database across multiple satellites, over full mission life cycles, that minimizes coupling with the core ground control system such that the use across different ground systems is maximized. This paper discusses the specific approach taken in evaluating the C&T database development for APL's past missions and the shortfalls that were encountered. Lessons learned were evaluated and decisions were made in implementing the RBSP C&T databases. The tool development is briefly discussed with an emphasis on the engineering use during satellite subsystem development. Recent successes during the testing are also presented. Finally, plans are described for continued improvement to the approach and tools for subsequent APL spacecraft so that the C&T database can be ported to other missions of interest.","PeriodicalId":110721,"journal":{"name":"2011 IEEE AUTOTESTCON","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132785858","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 : 2011-10-24DOI: 10.1109/AUTEST.2011.6058761
Rich Hooper
One of the most common architectural decisions facing the designer of Automated Test Equipment (ATE) is the switching, or multiplexing, of limited ATE stimulus and measurement resources between multiple test points at the Unit Under Test (UUT). In the abstract these switches and the associated cabling, interface chassis, etc. form a mapping layer between the tester resources and the UUT test points. When deciding on a switching architecture the ATE designer must consider multiple performance criteria including: cost, size, signal quality, reliability and serviceability. This paper looks at the various switching architecture options available to the ATE designer and provides guidance for choosing the best architecture for the application.
{"title":"Optimal switching architecture for Automated Test Equipment","authors":"Rich Hooper","doi":"10.1109/AUTEST.2011.6058761","DOIUrl":"https://doi.org/10.1109/AUTEST.2011.6058761","url":null,"abstract":"One of the most common architectural decisions facing the designer of Automated Test Equipment (ATE) is the switching, or multiplexing, of limited ATE stimulus and measurement resources between multiple test points at the Unit Under Test (UUT). In the abstract these switches and the associated cabling, interface chassis, etc. form a mapping layer between the tester resources and the UUT test points. When deciding on a switching architecture the ATE designer must consider multiple performance criteria including: cost, size, signal quality, reliability and serviceability. This paper looks at the various switching architecture options available to the ATE designer and provides guidance for choosing the best architecture for the application.","PeriodicalId":110721,"journal":{"name":"2011 IEEE AUTOTESTCON","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132925154","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 : 2011-10-24DOI: 10.1109/AUTEST.2011.6058780
Mel Hocker, Virginia Slay
Interim results of ongoing research and analysis required to develop a template or analytical tool for business case analysis, (BCA) are presented. This paper provides the results of numerous queries of F-15A/B/C/D maintenance database and difficulties encountered while attempting to obtain maintenance and logistics data that could be used to both validate anecdotal evidence from the field and assess the total (enterprise) cost savings that are generated when an advanced O-level test capability is provided to the maintainer. It also provides a comparison between the F-15E (with full BIT capability) to the F-15A/B/C/D test approach that uses ATE for test and diagnostics. Lastly, it discusses the critical need and salient characteristics of a more advanced analytical tool that could be used by the sustainment engineer in the preparation of a business case for a proposed CBM+ project.
{"title":"Development of a business case template for organizational-level testers","authors":"Mel Hocker, Virginia Slay","doi":"10.1109/AUTEST.2011.6058780","DOIUrl":"https://doi.org/10.1109/AUTEST.2011.6058780","url":null,"abstract":"Interim results of ongoing research and analysis required to develop a template or analytical tool for business case analysis, (BCA) are presented. This paper provides the results of numerous queries of F-15A/B/C/D maintenance database and difficulties encountered while attempting to obtain maintenance and logistics data that could be used to both validate anecdotal evidence from the field and assess the total (enterprise) cost savings that are generated when an advanced O-level test capability is provided to the maintainer. It also provides a comparison between the F-15E (with full BIT capability) to the F-15A/B/C/D test approach that uses ATE for test and diagnostics. Lastly, it discusses the critical need and salient characteristics of a more advanced analytical tool that could be used by the sustainment engineer in the preparation of a business case for a proposed CBM+ project.","PeriodicalId":110721,"journal":{"name":"2011 IEEE AUTOTESTCON","volume":"134 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132702038","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 : 2011-10-24DOI: 10.1109/AUTEST.2011.6058748
T. Gohel
Automatic Test Equipment (ATE) is now testing Units Under Test (UUTs) with signals that operate with data rates of several gigabits per second. Therefore, the test engineer must understand and account for the signal degradation through the transmission path. These high-speed digital signals typically pass through a variety of transmission media between the input/output (I/O) buffers on the ATE to the I/O buffers on the UUT. This paper highlights several considerations for the test engineer who is creating the test and system setup for a multi-gigabit per second bus. The paper discusses the contributors to DC and AC signal loss as well as methods to help minimize these losses. The paper focuses on multi-gigabit applications with matched double terminated transmission lines, but also touches on slightly slower busses with other termination schemes.
{"title":"Where did my signal go? A discussion of signal loss between the ATE and UUT","authors":"T. Gohel","doi":"10.1109/AUTEST.2011.6058748","DOIUrl":"https://doi.org/10.1109/AUTEST.2011.6058748","url":null,"abstract":"Automatic Test Equipment (ATE) is now testing Units Under Test (UUTs) with signals that operate with data rates of several gigabits per second. Therefore, the test engineer must understand and account for the signal degradation through the transmission path. These high-speed digital signals typically pass through a variety of transmission media between the input/output (I/O) buffers on the ATE to the I/O buffers on the UUT. This paper highlights several considerations for the test engineer who is creating the test and system setup for a multi-gigabit per second bus. The paper discusses the contributors to DC and AC signal loss as well as methods to help minimize these losses. The paper focuses on multi-gigabit applications with matched double terminated transmission lines, but also touches on slightly slower busses with other termination schemes.","PeriodicalId":110721,"journal":{"name":"2011 IEEE AUTOTESTCON","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116812236","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 : 2011-10-24DOI: 10.1109/AUTEST.2011.6058768
I. A. Miller
A majority of National Aeronautics and Space Administration (NASA) and Department of Defense spacecraft require the ability to be maneuvered in space after separation from the launch vehicle. These maneuvers may be for station keeping, orbit insertion, collection of science data, or avoidance maneuvers. Many of these spacecraft utilize a liquid propulsion system involving thrusters, latch valves, propellant tanks, propellant lines, and associated pressure- and temperaturemonitoring equipment. To thoroughly test the propulsion system prior to launch, the spacecraft integration and test (I&T) team must put all of the propulsive elements through a series of tests, both electrical and mechanical, that include hazardous operations. Because of the repetitive nature of many of the tests, a propulsion test system (PTS) is desired; the PTS will include a mix of automated and manual elements to make electrical testing of the propulsion subsystem more efficient, repeatable, and safe.
{"title":"Proposed system for automating electrical verification and validation of spacecraft liquid propulsion systems","authors":"I. A. Miller","doi":"10.1109/AUTEST.2011.6058768","DOIUrl":"https://doi.org/10.1109/AUTEST.2011.6058768","url":null,"abstract":"A majority of National Aeronautics and Space Administration (NASA) and Department of Defense spacecraft require the ability to be maneuvered in space after separation from the launch vehicle. These maneuvers may be for station keeping, orbit insertion, collection of science data, or avoidance maneuvers. Many of these spacecraft utilize a liquid propulsion system involving thrusters, latch valves, propellant tanks, propellant lines, and associated pressure- and temperaturemonitoring equipment. To thoroughly test the propulsion system prior to launch, the spacecraft integration and test (I&T) team must put all of the propulsive elements through a series of tests, both electrical and mechanical, that include hazardous operations. Because of the repetitive nature of many of the tests, a propulsion test system (PTS) is desired; the PTS will include a mix of automated and manual elements to make electrical testing of the propulsion subsystem more efficient, repeatable, and safe.","PeriodicalId":110721,"journal":{"name":"2011 IEEE AUTOTESTCON","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127368613","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 : 2011-10-24DOI: 10.1109/AUTEST.2011.6058749
S. Narciso
The new AXIe standard is based on the ATCA standards and relieves some constraints of PXI, most notably the module size and power limitations. However AXIe does not replace PXI since PXI provides an excellent solution for applications that don't need the incremental AXIe capabilities. Many conventional systems will benefit from combining PXI, AXIe and rack and stack assets. This paper describes the common software and hardware interfaces available from each and how to integrate them all together.
{"title":"Creating test systems using AXIe and PXI modules","authors":"S. Narciso","doi":"10.1109/AUTEST.2011.6058749","DOIUrl":"https://doi.org/10.1109/AUTEST.2011.6058749","url":null,"abstract":"The new AXIe standard is based on the ATCA standards and relieves some constraints of PXI, most notably the module size and power limitations. However AXIe does not replace PXI since PXI provides an excellent solution for applications that don't need the incremental AXIe capabilities. Many conventional systems will benefit from combining PXI, AXIe and rack and stack assets. This paper describes the common software and hardware interfaces available from each and how to integrate them all together.","PeriodicalId":110721,"journal":{"name":"2011 IEEE AUTOTESTCON","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129201210","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 : 2011-10-24DOI: 10.1109/AUTEST.2011.6058766
Rich Hooper, Doug Shuffield, Ketan Merchant, D. Savage
A wide range of Radio Frequency (RF) assemblies require testing during their development and production. These include amplifiers, mixers, filters, up converters, down converters, antennas, phase shifters, power dividers, power combiners, Integrated Master Assemblies (IMAs), Weapons Replaceable Assemblies (WRAs), Line Replaceable Units (LRUs) and radio subassemblies. Though there are many differences between the RF assemblies, they all require a test system that is accurate, reliable and traceable while simultaneously minimizing test times. Other important attributes of a test platform for RF assemblies are that it must be calibrated, fully-characterized and incorporate self-test functionality. The test platform must also include a digital control solution for triggering, communicating with Units Under Test (UUT) and interfacing with handlers, fixtures, etc. Finally, the software for the test equipment must also be considered. Typical software functionality would include sequencing, reporting, testing, calibration, and self-test. While it is certainly possible to develop a test system specific to each type of RF assembly; there are many benefits to developing a common RF test platform that includes the functionality listed above.
{"title":"Common RF test platform","authors":"Rich Hooper, Doug Shuffield, Ketan Merchant, D. Savage","doi":"10.1109/AUTEST.2011.6058766","DOIUrl":"https://doi.org/10.1109/AUTEST.2011.6058766","url":null,"abstract":"A wide range of Radio Frequency (RF) assemblies require testing during their development and production. These include amplifiers, mixers, filters, up converters, down converters, antennas, phase shifters, power dividers, power combiners, Integrated Master Assemblies (IMAs), Weapons Replaceable Assemblies (WRAs), Line Replaceable Units (LRUs) and radio subassemblies. Though there are many differences between the RF assemblies, they all require a test system that is accurate, reliable and traceable while simultaneously minimizing test times. Other important attributes of a test platform for RF assemblies are that it must be calibrated, fully-characterized and incorporate self-test functionality. The test platform must also include a digital control solution for triggering, communicating with Units Under Test (UUT) and interfacing with handlers, fixtures, etc. Finally, the software for the test equipment must also be considered. Typical software functionality would include sequencing, reporting, testing, calibration, and self-test. While it is certainly possible to develop a test system specific to each type of RF assembly; there are many benefits to developing a common RF test platform that includes the functionality listed above.","PeriodicalId":110721,"journal":{"name":"2011 IEEE AUTOTESTCON","volume":"IA-21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126563042","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 : 2011-10-24DOI: 10.1109/AUTEST.2011.6058744
N. Yang
Electrical sensors, such as strain gages and thermocouples, have for decades been the standard mechanism for converting physical and mechanical phenomena into an analog signal that can be measured by a data acquisition system. Advances related to sensor measurements have mostly been focused on signal conditioning and sensor design. The fundamental operation of sensors remained the same: measuring an electrical potential difference and scaling it to physical engineering units.
{"title":"Structural and physical measurements at the speed of light","authors":"N. Yang","doi":"10.1109/AUTEST.2011.6058744","DOIUrl":"https://doi.org/10.1109/AUTEST.2011.6058744","url":null,"abstract":"Electrical sensors, such as strain gages and thermocouples, have for decades been the standard mechanism for converting physical and mechanical phenomena into an analog signal that can be measured by a data acquisition system. Advances related to sensor measurements have mostly been focused on signal conditioning and sensor design. The fundamental operation of sensors remained the same: measuring an electrical potential difference and scaling it to physical engineering units.","PeriodicalId":110721,"journal":{"name":"2011 IEEE AUTOTESTCON","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125177048","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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