Pub Date : 2015-05-27DOI: 10.1109/WFCS.2015.7160572
Aasem Ahmad, Z. Hanzálek
We study one-collision domain ZigBee cluster-tree design problems to satisfy periodic time-bounded data flows. The formation of the cluster-tree topology can be seen as a bounded-degree-and-depth tree which is an NP-complete problem. The objective is to minimize the number of clusters such that all flows can take place and there exists a cluster schedule that meets the deadlines of the flows. For the resulting tree, the cluster schedule is required to be energy efficient, which can be achieved by maximizing the length of the schedule period, and consequently, increasing the lifetime of the network. We present a Cluster-Tree Formation and Energy-Efficient clusters scheduling algorithm, CFEFS, based on the Hungarian algorithm, the Maximum Matching algorithm and the Branch and Bound algorithm to tackle this design problem that integrates the cluster formation and the cluster scheduling in one problem.
{"title":"ZigBee cluster tree formation for time-bounded data flows in one collision domain","authors":"Aasem Ahmad, Z. Hanzálek","doi":"10.1109/WFCS.2015.7160572","DOIUrl":"https://doi.org/10.1109/WFCS.2015.7160572","url":null,"abstract":"We study one-collision domain ZigBee cluster-tree design problems to satisfy periodic time-bounded data flows. The formation of the cluster-tree topology can be seen as a bounded-degree-and-depth tree which is an NP-complete problem. The objective is to minimize the number of clusters such that all flows can take place and there exists a cluster schedule that meets the deadlines of the flows. For the resulting tree, the cluster schedule is required to be energy efficient, which can be achieved by maximizing the length of the schedule period, and consequently, increasing the lifetime of the network. We present a Cluster-Tree Formation and Energy-Efficient clusters scheduling algorithm, CFEFS, based on the Hungarian algorithm, the Maximum Matching algorithm and the Branch and Bound algorithm to tackle this design problem that integrates the cluster formation and the cluster scheduling in one problem.","PeriodicalId":6531,"journal":{"name":"2015 IEEE World Conference on Factory Communication Systems (WFCS)","volume":"80 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2015-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76093820","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 : 2015-05-27DOI: 10.1109/WFCS.2015.7160545
Waled Al-Makhawi, R. Obermaisser
Embedded systems have gained immense importance in various domains and they evolve rapidly driven by the necessity to cope with new emerging technologies and new required functionalities. The requirements of evolving embedded systems are subject to changes, thereby leading to repeated redesigns. In model-driven engineering the application's functional and nonfunctional requirements are specified separately from the underlying execution platform. Scheduling is the process of allocating the services of the application model onto the available resources of the platform model. Due to the continuous changes and updates in evolving embedded systems the rescheduling process becomes a critical challenge, because the output of scheduling can be significantly different even upon small changes. This avalanche effect leads to high effort and cost for recertification and revalidation. The contribution of this paper is a method for incremental scheduling, which minimizes the number of changed resource allocations while also satisfying the application's temporal constraints. The incremental scheduling is realized using Mixed Integer Linear Programming (MILP) and the IBM CPLEX optimizer. The presented results allow to reduce cost for recertification and revalidation compared to state-of-the-art scheduling methods.
{"title":"Minimizing revalidation and recertification in evolutionary embedded systems","authors":"Waled Al-Makhawi, R. Obermaisser","doi":"10.1109/WFCS.2015.7160545","DOIUrl":"https://doi.org/10.1109/WFCS.2015.7160545","url":null,"abstract":"Embedded systems have gained immense importance in various domains and they evolve rapidly driven by the necessity to cope with new emerging technologies and new required functionalities. The requirements of evolving embedded systems are subject to changes, thereby leading to repeated redesigns. In model-driven engineering the application's functional and nonfunctional requirements are specified separately from the underlying execution platform. Scheduling is the process of allocating the services of the application model onto the available resources of the platform model. Due to the continuous changes and updates in evolving embedded systems the rescheduling process becomes a critical challenge, because the output of scheduling can be significantly different even upon small changes. This avalanche effect leads to high effort and cost for recertification and revalidation. The contribution of this paper is a method for incremental scheduling, which minimizes the number of changed resource allocations while also satisfying the application's temporal constraints. The incremental scheduling is realized using Mixed Integer Linear Programming (MILP) and the IBM CPLEX optimizer. The presented results allow to reduce cost for recertification and revalidation compared to state-of-the-art scheduling methods.","PeriodicalId":6531,"journal":{"name":"2015 IEEE World Conference on Factory Communication Systems (WFCS)","volume":"228 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2015-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84835831","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 : 2015-05-27DOI: 10.1109/WFCS.2015.7160576
P. Rodriguez, I. Val, Aitor Lizeaga, M. Mendicute
The evaluation of Cognitive Radio (CR) for Wireless Sensor and Actuator Networks (WSANs) in industrial wireless automation applications is presented in this contribution. Current wireless solutions do not ensure enough performance for hard real-time and reliability requirements, based on time-critical data traffic. These industrial applications are characterized by harsh environments, where the robustness of wireless communications plays an important role. In these kinds of environments, CR can increase the system's reliability and robustness. Thus, several cognitive and non-cognitive MACs which ensure mission-critical and time-critical data transmission have been evaluated through OPNET network simulator over several fading and interference channels. The provided results show that CR-based MACs are able to maintain the performance of the network in harsh channels and under interference.
{"title":"Evaluation of cognitive radio for mission-critical and time-critical WSAN in industrial environments under interference","authors":"P. Rodriguez, I. Val, Aitor Lizeaga, M. Mendicute","doi":"10.1109/WFCS.2015.7160576","DOIUrl":"https://doi.org/10.1109/WFCS.2015.7160576","url":null,"abstract":"The evaluation of Cognitive Radio (CR) for Wireless Sensor and Actuator Networks (WSANs) in industrial wireless automation applications is presented in this contribution. Current wireless solutions do not ensure enough performance for hard real-time and reliability requirements, based on time-critical data traffic. These industrial applications are characterized by harsh environments, where the robustness of wireless communications plays an important role. In these kinds of environments, CR can increase the system's reliability and robustness. Thus, several cognitive and non-cognitive MACs which ensure mission-critical and time-critical data transmission have been evaluated through OPNET network simulator over several fading and interference channels. The provided results show that CR-based MACs are able to maintain the performance of the network in harsh channels and under interference.","PeriodicalId":6531,"journal":{"name":"2015 IEEE World Conference on Factory Communication Systems (WFCS)","volume":"78 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2015-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78087822","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 : 2015-05-27DOI: 10.1109/WFCS.2015.7160570
Ralf Schlesinger, A. Springer, T. Sauter
Profinet IRT makes use of dynamic frame packing (DFP) in order to support very short cycle times. The applied packing order is highly dependent on the network topology, and thus the scheduling must be recalculated offline every time the network structure is changed. This study presents a proposal for an automatic packing mechanism (APM) that is based on subframes with delimiters using control characters. As a consequence the subframe positions can be recognized by each device, which makes a scheduling dispensable. Furthermore, APM achieves better performance than DFP, especially in star or tree topology. The paper also presents experimental validation results.
{"title":"Improving profinet IRT frame packing using ethernet control characters","authors":"Ralf Schlesinger, A. Springer, T. Sauter","doi":"10.1109/WFCS.2015.7160570","DOIUrl":"https://doi.org/10.1109/WFCS.2015.7160570","url":null,"abstract":"Profinet IRT makes use of dynamic frame packing (DFP) in order to support very short cycle times. The applied packing order is highly dependent on the network topology, and thus the scheduling must be recalculated offline every time the network structure is changed. This study presents a proposal for an automatic packing mechanism (APM) that is based on subframes with delimiters using control characters. As a consequence the subframe positions can be recognized by each device, which makes a scheduling dispensable. Furthermore, APM achieves better performance than DFP, especially in star or tree topology. The paper also presents experimental validation results.","PeriodicalId":6531,"journal":{"name":"2015 IEEE World Conference on Factory Communication Systems (WFCS)","volume":"90 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2015-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80421981","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 : 2015-05-27DOI: 10.1109/WFCS.2015.7160559
A. Buda, Kary Främling, J. Borgman, Manik Madhikermi, Saeed Mirzaeifar, S. Kubler
The Industrial Internet promises to radically change and improve many industry's daily business activities, from simple data collection and processing to context-driven, intelligent and pro-active support of workers' everyday tasks and life. The present paper first provides insight into a typical industrial internet application architecture, then it highlights one fundamental arising contradiction: “Who owns the data is often not capable of analyzing it”. This statement is explained by imaging a visionary data supply chain that would realize some of the Industrial Internet promises. To concretely implement such a system, recent standards published by The Open Group are presented, where we highlight the characteristics that make them suitable for Industrial Internet applications. Finally, we discuss comparable solutions and concludes with new business use cases.
{"title":"Data supply chain in Industrial Internet","authors":"A. Buda, Kary Främling, J. Borgman, Manik Madhikermi, Saeed Mirzaeifar, S. Kubler","doi":"10.1109/WFCS.2015.7160559","DOIUrl":"https://doi.org/10.1109/WFCS.2015.7160559","url":null,"abstract":"The Industrial Internet promises to radically change and improve many industry's daily business activities, from simple data collection and processing to context-driven, intelligent and pro-active support of workers' everyday tasks and life. The present paper first provides insight into a typical industrial internet application architecture, then it highlights one fundamental arising contradiction: “Who owns the data is often not capable of analyzing it”. This statement is explained by imaging a visionary data supply chain that would realize some of the Industrial Internet promises. To concretely implement such a system, recent standards published by The Open Group are presented, where we highlight the characteristics that make them suitable for Industrial Internet applications. Finally, we discuss comparable solutions and concludes with new business use cases.","PeriodicalId":6531,"journal":{"name":"2015 IEEE World Conference on Factory Communication Systems (WFCS)","volume":"66 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2015-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81024553","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 : 2015-05-27DOI: 10.1109/WFCS.2015.7160561
Daniel Schachinger, W. Kastner
Accessing building automation systems (BASs) via standardized interfaces gains importance in the context of the Internet of Things (IoT). Web service gateway technologies can be used to integrate BASs in order to provide access via common Web interfaces. Therefore, an integration approach supporting multiple building automation technologies as well as multiple gateway technologies is needed. For this purpose, the model-driven methodology is used to define such a procedure. In this paper, an efficient, automatic, and reusable workflow for the integration of BASs into the IoT is presented by means of specifying modeling languages, model transformations, and code generation in accordance with the concept of Model-Driven Architecture (MDA). The aim is to convert a platform-independent model of a BAS into executable program code representing the underlying datapoints. Furthermore, a proof-of-concept implementation based on an exemplary BAS is implemented and evaluated in order to demonstrate the functionality and the advantages of this model-driven approach.
{"title":"Model-driven integration of building automation systems into Web service gateways","authors":"Daniel Schachinger, W. Kastner","doi":"10.1109/WFCS.2015.7160561","DOIUrl":"https://doi.org/10.1109/WFCS.2015.7160561","url":null,"abstract":"Accessing building automation systems (BASs) via standardized interfaces gains importance in the context of the Internet of Things (IoT). Web service gateway technologies can be used to integrate BASs in order to provide access via common Web interfaces. Therefore, an integration approach supporting multiple building automation technologies as well as multiple gateway technologies is needed. For this purpose, the model-driven methodology is used to define such a procedure. In this paper, an efficient, automatic, and reusable workflow for the integration of BASs into the IoT is presented by means of specifying modeling languages, model transformations, and code generation in accordance with the concept of Model-Driven Architecture (MDA). The aim is to convert a platform-independent model of a BAS into executable program code representing the underlying datapoints. Furthermore, a proof-of-concept implementation based on an exemplary BAS is implemented and evaluated in order to demonstrate the functionality and the advantages of this model-driven approach.","PeriodicalId":6531,"journal":{"name":"2015 IEEE World Conference on Factory Communication Systems (WFCS)","volume":"44 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2015-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88188419","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 : 2015-05-27DOI: 10.1109/WFCS.2015.7160568
F. Tramarin, S. Vitturi, Michele Luvisotto, A. Zanella
In the last years, IEEE 802.11 Wireless LANs (WLANs) have proved their effectiveness for a wide range of real-time industrial communication applications. Nonetheless, the enhancements at the PHY and MAC layers introduced by the IEEE 802.11n amendment have not yet been adequately addressed in the context of industrial communication. In this paper we investigate the impact of some IEEE 802.11n new features on some important performance figures for industrial applications, such as timeliness and reliability.
{"title":"The IEEE 802.11n wireless LAN for real-time industrial communication","authors":"F. Tramarin, S. Vitturi, Michele Luvisotto, A. Zanella","doi":"10.1109/WFCS.2015.7160568","DOIUrl":"https://doi.org/10.1109/WFCS.2015.7160568","url":null,"abstract":"In the last years, IEEE 802.11 Wireless LANs (WLANs) have proved their effectiveness for a wide range of real-time industrial communication applications. Nonetheless, the enhancements at the PHY and MAC layers introduced by the IEEE 802.11n amendment have not yet been adequately addressed in the context of industrial communication. In this paper we investigate the impact of some IEEE 802.11n new features on some important performance figures for industrial applications, such as timeliness and reliability.","PeriodicalId":6531,"journal":{"name":"2015 IEEE World Conference on Factory Communication Systems (WFCS)","volume":"85 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2015-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81196126","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 : 2015-05-27DOI: 10.1109/WFCS.2015.7160580
F. Tramarin, S. Vitturi, Michele Luvisotto
IEEE 802.11 systems are drawing an ever increasing interest for wireless industrial communication, also thanks to the interesting features provided by the most recent and advanced amendments to this standard, such as IEEE 802.11n. Due to the intrinsic unreliability of the wireless medium, the current research efforts aim at improving both timeliness and reliability of such a protocol in view of its adoption for real-time applications. A significant issue in this context is represented by the reduction of the randomness that affects packet delivery times. An important benefit in this direction can be obtained by the deactivation of the standard legacy carrier sensing and backoff procedures. In this paper we show, through a simulative assessment, that a fine control of such features leads to improved real-time performance.
{"title":"Enhancing the real-time behavior of IEEE 802.11n","authors":"F. Tramarin, S. Vitturi, Michele Luvisotto","doi":"10.1109/WFCS.2015.7160580","DOIUrl":"https://doi.org/10.1109/WFCS.2015.7160580","url":null,"abstract":"IEEE 802.11 systems are drawing an ever increasing interest for wireless industrial communication, also thanks to the interesting features provided by the most recent and advanced amendments to this standard, such as IEEE 802.11n. Due to the intrinsic unreliability of the wireless medium, the current research efforts aim at improving both timeliness and reliability of such a protocol in view of its adoption for real-time applications. A significant issue in this context is represented by the reduction of the randomness that affects packet delivery times. An important benefit in this direction can be obtained by the deactivation of the standard legacy carrier sensing and backoff procedures. In this paper we show, through a simulative assessment, that a fine control of such features leads to improved real-time performance.","PeriodicalId":6531,"journal":{"name":"2015 IEEE World Conference on Factory Communication Systems (WFCS)","volume":"31 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2015-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85176354","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 : 2015-05-27DOI: 10.1109/WFCS.2015.7160569
A. Mahmood, R. Exel, T. Sauter
The absence of built-in clock synchronization support for IEEE 802.11 networks has been a concern for industrial applications which are seeking to use wireless networking on the factory floor. In IEEE 802.11-2012, the timing advertisement (TA) mechanism is proposed which provides guidelines for the application synchronization. It involves calculating and maintaining the time offset with respect to the timing synchronization function (TSF) timer of the access point. In the wireless stations, the TSF-based synchronization mechanism and the offset are combined to establish synchronization to an external timebase. With respect to the lack of implementation guidelines and support for the TA scheme, this paper compares and discusses the TA scheme and the software-based SyncTSF scheme previously proposed by the authors, which employs the TSF timer as the timing source in the network. The initial simulation results show that both schemes can provide similar performance, depending upon the controller design and the timestamping technique.
{"title":"A simulation-based comparison of IEEE 802.11's timing advertisement and SyncTSF for clock synchronization","authors":"A. Mahmood, R. Exel, T. Sauter","doi":"10.1109/WFCS.2015.7160569","DOIUrl":"https://doi.org/10.1109/WFCS.2015.7160569","url":null,"abstract":"The absence of built-in clock synchronization support for IEEE 802.11 networks has been a concern for industrial applications which are seeking to use wireless networking on the factory floor. In IEEE 802.11-2012, the timing advertisement (TA) mechanism is proposed which provides guidelines for the application synchronization. It involves calculating and maintaining the time offset with respect to the timing synchronization function (TSF) timer of the access point. In the wireless stations, the TSF-based synchronization mechanism and the offset are combined to establish synchronization to an external timebase. With respect to the lack of implementation guidelines and support for the TA scheme, this paper compares and discusses the TA scheme and the software-based SyncTSF scheme previously proposed by the authors, which employs the TSF timer as the timing source in the network. The initial simulation results show that both schemes can provide similar performance, depending upon the controller design and the timestamping technique.","PeriodicalId":6531,"journal":{"name":"2015 IEEE World Conference on Factory Communication Systems (WFCS)","volume":"45 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2015-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89820298","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 : 2015-05-27DOI: 10.1109/WFCS.2015.7160586
M. Miśkowicz, Jakub Szyduczynski, D. Koscielnik
The paper addresses the performance analysis of the multiple memoryless backoff contention in slotted-CSMA protocols. By multiple memoryless backoff (MMB) system we define a heterogeneous random access protocol when the contending stations sample from different numbers of contention slots, and the sampled backoff times are cancelled when the transmission is detected in the channel. The MMB contention occurs in practice in many random access networks usually due to different history of collisions experienced by particular stations (e.g. in binary exponential backoff in CSMA/CD IEEE 802.3, or in linear backoff used in predictive p-CSMA in LonTalk (ISO/IEC 14908). The MMB provides unequal allocation of bandwidth among the stations, and thus introduces unfairness in channel access. The paper contains derivations of analytical formulae for probabilities of successful and successful transmissions needed to determine throughput and mean access delay. Finally, sample numerical results for multiple memoryless backoff network are presented.
{"title":"Analytical approach to multiple memoryless backoff contention analysis","authors":"M. Miśkowicz, Jakub Szyduczynski, D. Koscielnik","doi":"10.1109/WFCS.2015.7160586","DOIUrl":"https://doi.org/10.1109/WFCS.2015.7160586","url":null,"abstract":"The paper addresses the performance analysis of the multiple memoryless backoff contention in slotted-CSMA protocols. By multiple memoryless backoff (MMB) system we define a heterogeneous random access protocol when the contending stations sample from different numbers of contention slots, and the sampled backoff times are cancelled when the transmission is detected in the channel. The MMB contention occurs in practice in many random access networks usually due to different history of collisions experienced by particular stations (e.g. in binary exponential backoff in CSMA/CD IEEE 802.3, or in linear backoff used in predictive p-CSMA in LonTalk (ISO/IEC 14908). The MMB provides unequal allocation of bandwidth among the stations, and thus introduces unfairness in channel access. The paper contains derivations of analytical formulae for probabilities of successful and successful transmissions needed to determine throughput and mean access delay. Finally, sample numerical results for multiple memoryless backoff network are presented.","PeriodicalId":6531,"journal":{"name":"2015 IEEE World Conference on Factory Communication Systems (WFCS)","volume":"52 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2015-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89481385","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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