Pub Date : 2012-04-24DOI: 10.1109/ICNSURV.2012.6218400
N. Kanada, Y. Sumiya, N. Yonemoto, S. Futatsumori, E. Isozaki
A new high-speed aeronautical digital communication system called Aeronautical Mobile Airport Communication System (AeroMACS) is currently being considered. This paper describes a study to evaluate the MIMO effect of different antenna configurations for this system in an airport environment. We first proposed an index to evaluate MIMO antenna systems. We then measured transmission coefficients between antennas mounted on an aircraft representing a mobile station and a road vehicle representing a base station at Sendai Airport, and then based on these measurements we compared the channel capacities between SISO, 2×2 MIMO, and 2×6 MIMO antenna systems. We also evaluated channel capacity under multipath rich and poor environments. We conclude that 2×6 MIMO antenna systems are the most effective under any conditions.
{"title":"MIMO effect evaluation for aeronautical WiMAX in airport at 5.1GHZ","authors":"N. Kanada, Y. Sumiya, N. Yonemoto, S. Futatsumori, E. Isozaki","doi":"10.1109/ICNSURV.2012.6218400","DOIUrl":"https://doi.org/10.1109/ICNSURV.2012.6218400","url":null,"abstract":"A new high-speed aeronautical digital communication system called Aeronautical Mobile Airport Communication System (AeroMACS) is currently being considered. This paper describes a study to evaluate the MIMO effect of different antenna configurations for this system in an airport environment. We first proposed an index to evaluate MIMO antenna systems. We then measured transmission coefficients between antennas mounted on an aircraft representing a mobile station and a road vehicle representing a base station at Sendai Airport, and then based on these measurements we compared the channel capacities between SISO, 2×2 MIMO, and 2×6 MIMO antenna systems. We also evaluated channel capacity under multipath rich and poor environments. We conclude that 2×6 MIMO antenna systems are the most effective under any conditions.","PeriodicalId":126055,"journal":{"name":"2012 Integrated Communications, Navigation and Surveillance Conference","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123313045","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 : 2012-04-24DOI: 10.1109/ICNSURV.2012.6218419
Brian Butka
Within the aviation industry RTCA DO-254 is the design assurance process for safety-critical airborne electronic hardware development. Safety-critical hardware (DAL A or B) requires the application of additional advanced verification techniques such as Elemental Analysis to ensure that elements of the design are adequately verified. This paper compares the verification processes currently used in the semiconductor industry to what is commonly used to meet DO-254 guidelines. Requirements based testing as specified in DO-254 is widely viewed as being inadequate to assure design correctness of complex hardware. Additional robustness testing techniques such as constrained random testing and assertions are typically used to improve the verification process. A methodology of subjecting the design to constrained random verification testing throughout the design process is examined. The applicability of this proposed process to DO-254 based design is evaluated.
{"title":"Advanced verification methods and safety critical hardware","authors":"Brian Butka","doi":"10.1109/ICNSURV.2012.6218419","DOIUrl":"https://doi.org/10.1109/ICNSURV.2012.6218419","url":null,"abstract":"Within the aviation industry RTCA DO-254 is the design assurance process for safety-critical airborne electronic hardware development. Safety-critical hardware (DAL A or B) requires the application of additional advanced verification techniques such as Elemental Analysis to ensure that elements of the design are adequately verified. This paper compares the verification processes currently used in the semiconductor industry to what is commonly used to meet DO-254 guidelines. Requirements based testing as specified in DO-254 is widely viewed as being inadequate to assure design correctness of complex hardware. Additional robustness testing techniques such as constrained random testing and assertions are typically used to improve the verification process. A methodology of subjecting the design to constrained random verification testing throughout the design process is examined. The applicability of this proposed process to DO-254 based design is evaluated.","PeriodicalId":126055,"journal":{"name":"2012 Integrated Communications, Navigation and Surveillance Conference","volume":"144 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128782660","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 : 2012-04-24DOI: 10.1109/ICNSURV.2012.6218417
D. Sislák, P. Volf, D. Pavlícek, M. Pechoucek
Increasing air-traffic demand implies that new air-traffic management (ATM) concepts lowering controller loads, maintaining safety and increasing efficiency need to be designed and implemented. Many of such ideas are prepared within NextGEN. Before they are deployed to real daily usage in National Airspace System (NAS), they must be rigorously evaluated under realistic conditions. The paper presents AGENTFLY, a NAS-wide high-fidelity distributed multi-agent simulator with precise emulation of the human controller operation workload model and human-system interaction. The current version of AGENTFLY provides precise modeling of the human radar controller (R-side) operating in en-route sector.
{"title":"Nas-wide en-route air-traffic controller modeling","authors":"D. Sislák, P. Volf, D. Pavlícek, M. Pechoucek","doi":"10.1109/ICNSURV.2012.6218417","DOIUrl":"https://doi.org/10.1109/ICNSURV.2012.6218417","url":null,"abstract":"Increasing air-traffic demand implies that new air-traffic management (ATM) concepts lowering controller loads, maintaining safety and increasing efficiency need to be designed and implemented. Many of such ideas are prepared within NextGEN. Before they are deployed to real daily usage in National Airspace System (NAS), they must be rigorously evaluated under realistic conditions. The paper presents AGENTFLY, a NAS-wide high-fidelity distributed multi-agent simulator with precise emulation of the human controller operation workload model and human-system interaction. The current version of AGENTFLY provides precise modeling of the human radar controller (R-side) operating in en-route sector.","PeriodicalId":126055,"journal":{"name":"2012 Integrated Communications, Navigation and Surveillance Conference","volume":"81 2 Suppl 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126220717","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 : 2012-04-24DOI: 10.1109/ICNSURV.2012.6218474
A. Mahashabde, William A. Baden, J. DeArmon, J. Harding, J. Field, Fred Bankert, Koffi Amefia
Presents a collection of slides from the author's conference presentation. This work enables assessment of tradeoffs between NextGen operational and environmental objectives at the NAS-wide scale
{"title":"Bridging the gap between air transportation system simulations and environmental models for NextGen benefits assessment","authors":"A. Mahashabde, William A. Baden, J. DeArmon, J. Harding, J. Field, Fred Bankert, Koffi Amefia","doi":"10.1109/ICNSURV.2012.6218474","DOIUrl":"https://doi.org/10.1109/ICNSURV.2012.6218474","url":null,"abstract":"Presents a collection of slides from the author's conference presentation. This work enables assessment of tradeoffs between NextGen operational and environmental objectives at the NAS-wide scale","PeriodicalId":126055,"journal":{"name":"2012 Integrated Communications, Navigation and Surveillance Conference","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126227537","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 : 2012-04-24DOI: 10.1109/ICNSURV.2012.6218483
R. Apaza, G. Kubat
{"title":"UAS in the NAS- control and non-payload communications modeling and simulation approach","authors":"R. Apaza, G. Kubat","doi":"10.1109/ICNSURV.2012.6218483","DOIUrl":"https://doi.org/10.1109/ICNSURV.2012.6218483","url":null,"abstract":"","PeriodicalId":126055,"journal":{"name":"2012 Integrated Communications, Navigation and Surveillance Conference","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127162311","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 : 2012-04-24DOI: 10.1109/ICNSURV.2012.6218432
R. Mayer
Advancing the National Airspace System (NAS) generally requires research to project the costs and benefits of proposed operational changes that improve system efficiency and environmental performance. Aviation regulatory agencies increasingly rely on aircraft fuel consumption and emissions assessments to support investment decisions needed to adopt new technologies that ensure the best value to the public. The varying scopes of such assessments and often limited availability of data to support evaluations of future change scenarios pose analytic challenges. This paper describes a methodological framework for standardizing benefit estimations. The framework is centered on the concept of operational change, identifies key benefit mechanisms, defines applicable metrics, and presents quantitative fuel burn and emission benefit estimation examples. It aims to support assessments that are based on on-board flight data, surveillance data, and model evaluations in a manner independent of specific implementations of simulation capabilities and software tools. The examples characterize and compare typical operational change scenarios on a parametric basis and rank associated benefit pools of actual changes observed in recent operational improvements including implementations of Performance Based Navigation (PBN) procedures at major airports in the NAS.
{"title":"Change-oriented aircraft fuel burn and emissions assessment methodologies","authors":"R. Mayer","doi":"10.1109/ICNSURV.2012.6218432","DOIUrl":"https://doi.org/10.1109/ICNSURV.2012.6218432","url":null,"abstract":"Advancing the National Airspace System (NAS) generally requires research to project the costs and benefits of proposed operational changes that improve system efficiency and environmental performance. Aviation regulatory agencies increasingly rely on aircraft fuel consumption and emissions assessments to support investment decisions needed to adopt new technologies that ensure the best value to the public. The varying scopes of such assessments and often limited availability of data to support evaluations of future change scenarios pose analytic challenges. This paper describes a methodological framework for standardizing benefit estimations. The framework is centered on the concept of operational change, identifies key benefit mechanisms, defines applicable metrics, and presents quantitative fuel burn and emission benefit estimation examples. It aims to support assessments that are based on on-board flight data, surveillance data, and model evaluations in a manner independent of specific implementations of simulation capabilities and software tools. The examples characterize and compare typical operational change scenarios on a parametric basis and rank associated benefit pools of actual changes observed in recent operational improvements including implementations of Performance Based Navigation (PBN) procedures at major airports in the NAS.","PeriodicalId":126055,"journal":{"name":"2012 Integrated Communications, Navigation and Surveillance Conference","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114801598","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 : 2012-04-24DOI: 10.1109/ICNSURV.2012.6218396
T. Graupl, B. Jandl, C. Rokitansky
Automation of aeronautical procedures and automated support tools for controllers and pilots have to be evaluated carefully with human operators in the loop. However, the integration of different vendor's operational aeronautical software applications with experimental support tools in simulated air-space environments is demanding and costly. Existing tools are usually not designed to be integrated with each other, thus an efficient and vendor-neutral way to integrate existing tools in a simple and efficient way is needed. This paper discusses a simple, efficient, and proven approach for the integration of a wide range of aeronautical software applications (commercial and academic, operational and experimental) in a unified human-in-the-loop evaluation environment. This approach integrates existing simulation and support tools using a simple software adapter to distribute shared simulation state in an internet-protocol-based multicast cloud using XML as presentation layer.
{"title":"Simple and efficient integration of aeronautical support tools for human-in-the-loop evaluations","authors":"T. Graupl, B. Jandl, C. Rokitansky","doi":"10.1109/ICNSURV.2012.6218396","DOIUrl":"https://doi.org/10.1109/ICNSURV.2012.6218396","url":null,"abstract":"Automation of aeronautical procedures and automated support tools for controllers and pilots have to be evaluated carefully with human operators in the loop. However, the integration of different vendor's operational aeronautical software applications with experimental support tools in simulated air-space environments is demanding and costly. Existing tools are usually not designed to be integrated with each other, thus an efficient and vendor-neutral way to integrate existing tools in a simple and efficient way is needed. This paper discusses a simple, efficient, and proven approach for the integration of a wide range of aeronautical software applications (commercial and academic, operational and experimental) in a unified human-in-the-loop evaluation environment. This approach integrates existing simulation and support tools using a simple software adapter to distribute shared simulation state in an internet-protocol-based multicast cloud using XML as presentation layer.","PeriodicalId":126055,"journal":{"name":"2012 Integrated Communications, Navigation and Surveillance Conference","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134207030","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 : 2012-04-24DOI: 10.1109/ICNSURV.2012.6218414
B. Birkmeier, J. Schmid, A. Schmitt, B. Korn
In a sectorless air traffic management concept the airspace is not divided into sectors but seen as one piece. An air traffic controller is no longer in charge of a sector but is responsible for individual flights which he or she controls from the entry into the airspace to the exit. This means that the controller has to keep track of several flights and traffic situations which might not be in the same geographic region. Of course, such a considerable change of concept influences the tasks and way of working for the controller. This paper gives first results about how a sectorless concept might change controller tasks. Real time simulations conducted at DLR provided first indications regarding changes in controller tasks, which are presented and analyzed. A preliminary task analysis is provided and discussed. We review different task models for a sectored concept and use them for a comparison of tasks in a sectored and a sectorless concept. Coordination with adjoining sectors is no longer necessary in a sectorless concept. In addition, the introduction of conflict detection tools and other automatic support systems could relieve the controller of planning tasks, thus shifting the main tasks more towards tactic control and monitoring. The discussion suggests a work environment and procedures which help the controller to exploit the benefits of sectorless control while retaining situational awareness.
{"title":"Change of controller tasks in a sectorless ATM concept - first results","authors":"B. Birkmeier, J. Schmid, A. Schmitt, B. Korn","doi":"10.1109/ICNSURV.2012.6218414","DOIUrl":"https://doi.org/10.1109/ICNSURV.2012.6218414","url":null,"abstract":"In a sectorless air traffic management concept the airspace is not divided into sectors but seen as one piece. An air traffic controller is no longer in charge of a sector but is responsible for individual flights which he or she controls from the entry into the airspace to the exit. This means that the controller has to keep track of several flights and traffic situations which might not be in the same geographic region. Of course, such a considerable change of concept influences the tasks and way of working for the controller. This paper gives first results about how a sectorless concept might change controller tasks. Real time simulations conducted at DLR provided first indications regarding changes in controller tasks, which are presented and analyzed. A preliminary task analysis is provided and discussed. We review different task models for a sectored concept and use them for a comparison of tasks in a sectored and a sectorless concept. Coordination with adjoining sectors is no longer necessary in a sectorless concept. In addition, the introduction of conflict detection tools and other automatic support systems could relieve the controller of planning tasks, thus shifting the main tasks more towards tactic control and monitoring. The discussion suggests a work environment and procedures which help the controller to exploit the benefits of sectorless control while retaining situational awareness.","PeriodicalId":126055,"journal":{"name":"2012 Integrated Communications, Navigation and Surveillance Conference","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129964238","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 : 2012-04-24DOI: 10.1109/ICNSURV.2012.6218411
S. Wenchel, G. Coville
The proximity of satellite airports to primary airports increases airspace complexity resulting in all aircraft having to compete for constrained airspace. When passing through constrained airspace, aircraft need to be slowed down, leveled off, or vectored to avoid each other, leading to increases in flight delays, fuel burn and Air Traffic Control (ATC) workload. The MITRE Corporation's Center for Advanced Aviation System Development (CAASD) has developed a capability to identify and graphically display areas of constrained airspace. This capability provides a means to determine where procedural adjustments, particularly those which make use of PBN capabilities, could result in deconflicted and more efficient operations. A transparent and automated methodology was developed and the results from this capability are provided in both a tabulated and graphical format using the Keyhole Markup Language (KML), allowing the concepts to be easily communicated to a wide audience. This capability has been successfully applied at 48 airports across the National Airspace System (NAS) and the findings were reviewed positively by ATC subject matter experts.
{"title":"Identification and visualization of constrained airspaces","authors":"S. Wenchel, G. Coville","doi":"10.1109/ICNSURV.2012.6218411","DOIUrl":"https://doi.org/10.1109/ICNSURV.2012.6218411","url":null,"abstract":"The proximity of satellite airports to primary airports increases airspace complexity resulting in all aircraft having to compete for constrained airspace. When passing through constrained airspace, aircraft need to be slowed down, leveled off, or vectored to avoid each other, leading to increases in flight delays, fuel burn and Air Traffic Control (ATC) workload. The MITRE Corporation's Center for Advanced Aviation System Development (CAASD) has developed a capability to identify and graphically display areas of constrained airspace. This capability provides a means to determine where procedural adjustments, particularly those which make use of PBN capabilities, could result in deconflicted and more efficient operations. A transparent and automated methodology was developed and the results from this capability are provided in both a tabulated and graphical format using the Keyhole Markup Language (KML), allowing the concepts to be easily communicated to a wide audience. This capability has been successfully applied at 48 airports across the National Airspace System (NAS) and the findings were reviewed positively by ATC subject matter experts.","PeriodicalId":126055,"journal":{"name":"2012 Integrated Communications, Navigation and Surveillance Conference","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132941366","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 : 2012-04-24DOI: 10.1109/ICNSURV.2012.6218415
A. Bell
For decades, safe Air Traffic Management services have been provided by maintaining sufficient distance between aircraft to ensure adequate reaction time for collision avoidance. With RADAR and voice communication as fundamental tools, separation requirements have evolved that recognize the relationship between speed and time, and convert these requirements to distance-based standards. This paper reviews physical relationships between altitude, airspeed, and environmental variables that determine the collision avoidance time between aircraft separated by existing distance-based standards to expose the inherent weaknesses of the conversion and establishes an alternative: time-based separation standards. Using data gathered through flight tests and simulations over the past two years, the performance of a modern aircraft Flight Management System (FMS) has been characterized by a distribution that expresses the probability of deviations from an assigned Required Time of Arrival (RTA). Using this distribution, a mathematical relationship between the probability of a collision and the time interval between aircraft has been developed. The equations allow the evaluation of collision probability for any given interval, or alternatively, allow calculation of a required time interval between aircraft to achieve any desired level of collision probability. These calculations then serve as the basis for development of a precise performance metric that may be used as a certification standard for RTA capable systems. The paper concludes with a number of suggestions for possible refinements to current air traffic management systems. Graphical depictions of symbology adaptations designed to provide an intuitive display of separation time between aircraft are presented along with possible innovations in implementation strategy for time-based sequencing and separation methods. Additionally, several procedural changes are described that provide modest immediate benefits and may satisfy pre-requisites to implementation of time-based operations.
{"title":"Developing standards for time-based sequencing & separation of aircraft","authors":"A. Bell","doi":"10.1109/ICNSURV.2012.6218415","DOIUrl":"https://doi.org/10.1109/ICNSURV.2012.6218415","url":null,"abstract":"For decades, safe Air Traffic Management services have been provided by maintaining sufficient distance between aircraft to ensure adequate reaction time for collision avoidance. With RADAR and voice communication as fundamental tools, separation requirements have evolved that recognize the relationship between speed and time, and convert these requirements to distance-based standards. This paper reviews physical relationships between altitude, airspeed, and environmental variables that determine the collision avoidance time between aircraft separated by existing distance-based standards to expose the inherent weaknesses of the conversion and establishes an alternative: time-based separation standards. Using data gathered through flight tests and simulations over the past two years, the performance of a modern aircraft Flight Management System (FMS) has been characterized by a distribution that expresses the probability of deviations from an assigned Required Time of Arrival (RTA). Using this distribution, a mathematical relationship between the probability of a collision and the time interval between aircraft has been developed. The equations allow the evaluation of collision probability for any given interval, or alternatively, allow calculation of a required time interval between aircraft to achieve any desired level of collision probability. These calculations then serve as the basis for development of a precise performance metric that may be used as a certification standard for RTA capable systems. The paper concludes with a number of suggestions for possible refinements to current air traffic management systems. Graphical depictions of symbology adaptations designed to provide an intuitive display of separation time between aircraft are presented along with possible innovations in implementation strategy for time-based sequencing and separation methods. Additionally, several procedural changes are described that provide modest immediate benefits and may satisfy pre-requisites to implementation of time-based operations.","PeriodicalId":126055,"journal":{"name":"2012 Integrated Communications, Navigation and Surveillance Conference","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121192269","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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