Pub Date : 2007-06-10DOI: 10.1109/LANMAN.2007.4295987
Elena López-Aguilera, M. Heusse, F. Rousseau, A. Duda, J. Casademont
In this paper, we present an evaluation of chosen wireless LAN access methods involving stations with different bit error rates: n-1 stations in ideal transmission conditions (BER = 0) and 1 station with a given bit error rate (BER ne 0). The simulation results show that the IEEE 802.11 DCF and its modifications (Slow Decrease, AOB) are very sensitive to transmission errors, whereas Idle Sense provides good channel access fairness: the value of the contention window is almost the same regardless of transmission errors, so that the throughput difference between stations subject to different bit error rates corresponds only to the proportion of lost frames.
{"title":"Channel Access Unfairness of Wireless LAN Access Methods","authors":"Elena López-Aguilera, M. Heusse, F. Rousseau, A. Duda, J. Casademont","doi":"10.1109/LANMAN.2007.4295987","DOIUrl":"https://doi.org/10.1109/LANMAN.2007.4295987","url":null,"abstract":"In this paper, we present an evaluation of chosen wireless LAN access methods involving stations with different bit error rates: n-1 stations in ideal transmission conditions (BER = 0) and 1 station with a given bit error rate (BER ne 0). The simulation results show that the IEEE 802.11 DCF and its modifications (Slow Decrease, AOB) are very sensitive to transmission errors, whereas Idle Sense provides good channel access fairness: the value of the contention window is almost the same regardless of transmission errors, so that the throughput difference between stations subject to different bit error rates corresponds only to the proportion of lost frames.","PeriodicalId":347028,"journal":{"name":"2007 15th IEEE Workshop on Local & Metropolitan Area Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122989937","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 : 2007-06-10DOI: 10.1109/LANMAN.2007.4295989
C. Tarhini, T. Chahed
We study in this paper the capacity of the downlink of OFDMA-based IEEE802.16 WiMAX system in the presence of two types of traffic, streaming and elastic. We focus in particular on the impact of Adaptive Modulation and Coding (AMC) as well as inter-cell interference resulting from different frequency reuse schemes. Several performance measures, namely blocking rates, mean transfer time and the mean number of collisions between two OFDMA WiMAX cells, are then derived and quantified. We show that reuse partitioning results in a lower blocking probability for streaming flows in the inner region but a much higher one for elastic flows in the outer region; the overall cell throughput increases meaning that the decrease in the number of collisions improves the overall throughput.
{"title":"On capacity of OFDMA-based IEEE802.16 WiMAX including Adaptive Modulation and Coding (AMC) and inter-cell interference","authors":"C. Tarhini, T. Chahed","doi":"10.1109/LANMAN.2007.4295989","DOIUrl":"https://doi.org/10.1109/LANMAN.2007.4295989","url":null,"abstract":"We study in this paper the capacity of the downlink of OFDMA-based IEEE802.16 WiMAX system in the presence of two types of traffic, streaming and elastic. We focus in particular on the impact of Adaptive Modulation and Coding (AMC) as well as inter-cell interference resulting from different frequency reuse schemes. Several performance measures, namely blocking rates, mean transfer time and the mean number of collisions between two OFDMA WiMAX cells, are then derived and quantified. We show that reuse partitioning results in a lower blocking probability for streaming flows in the inner region but a much higher one for elastic flows in the outer region; the overall cell throughput increases meaning that the decrease in the number of collisions improves the overall throughput.","PeriodicalId":347028,"journal":{"name":"2007 15th IEEE Workshop on Local & Metropolitan Area Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130233367","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 : 2007-06-10DOI: 10.1109/LANMAN.2007.4295992
Bow-Nan Cheng, M. Yuksel, S. Kalyanaraman
Routing in multi-hop wireless networks involves the indirection from a persistent name (or ID) to a locator. One of the biggest issues in routing is providing adequate connectivity while scaling the network. Recently, Bow-Nan Cheng et al., (2006) has attempted to mitigate this issue by using directional communication methods to find intersections between source-rendezvous and rendezvous-destination paths, providing effective routing in unstructured, flat networks. Cheng et al. showed that by "drawing" two lines orthogonal to each other at each node, it is possible to provide over 98% connectivity while maintaining only order O(N3/2) states. It is interesting, however to investigate what happens when additional lines are "drawn" and how that affects connectivity, path length and state complexity. In this paper, we examine how transmitting along one, two, three, and four lines affects routing and provide both analytical bounds for connectivity as well as packetized simulations on how these methods stack up in a more realistic environment. We show that by sending packets out in more directions, increased connectivity and smaller average path length results only up to a point. The trade-off, however, is added state information maintained at each node. We also show that in mobile environments, adding additional lines increases the chances for successful packet delivery only marginally.
{"title":"Directional Routing for Wireless Mesh Networks: A Performance Evaluation","authors":"Bow-Nan Cheng, M. Yuksel, S. Kalyanaraman","doi":"10.1109/LANMAN.2007.4295992","DOIUrl":"https://doi.org/10.1109/LANMAN.2007.4295992","url":null,"abstract":"Routing in multi-hop wireless networks involves the indirection from a persistent name (or ID) to a locator. One of the biggest issues in routing is providing adequate connectivity while scaling the network. Recently, Bow-Nan Cheng et al., (2006) has attempted to mitigate this issue by using directional communication methods to find intersections between source-rendezvous and rendezvous-destination paths, providing effective routing in unstructured, flat networks. Cheng et al. showed that by \"drawing\" two lines orthogonal to each other at each node, it is possible to provide over 98% connectivity while maintaining only order O(N3/2) states. It is interesting, however to investigate what happens when additional lines are \"drawn\" and how that affects connectivity, path length and state complexity. In this paper, we examine how transmitting along one, two, three, and four lines affects routing and provide both analytical bounds for connectivity as well as packetized simulations on how these methods stack up in a more realistic environment. We show that by sending packets out in more directions, increased connectivity and smaller average path length results only up to a point. The trade-off, however, is added state information maintained at each node. We also show that in mobile environments, adding additional lines increases the chances for successful packet delivery only marginally.","PeriodicalId":347028,"journal":{"name":"2007 15th IEEE Workshop on Local & Metropolitan Area Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123215734","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 : 2007-06-10DOI: 10.1109/LANMAN.2007.4295984
K. Katsaros, George C. Polyzos
Recent advances in mobile communications and computing and strong interest of the scientific community in the Grid have led to research into the Mobile Grid. We discuss various approaches proposed in the literature and try to point out the fundamental issues and problems emerging from the introduction of mobile devices and wireless communications in the context of the Grid computing paradigm. We further propose an architecture for the realization of a Mobile Grid and investigate key design decisions and optimizations.
{"title":"Optimizing Operation of a Hierarchical Campus-wide Mobile Grid for Intermittent Wireless Connectivity","authors":"K. Katsaros, George C. Polyzos","doi":"10.1109/LANMAN.2007.4295984","DOIUrl":"https://doi.org/10.1109/LANMAN.2007.4295984","url":null,"abstract":"Recent advances in mobile communications and computing and strong interest of the scientific community in the Grid have led to research into the Mobile Grid. We discuss various approaches proposed in the literature and try to point out the fundamental issues and problems emerging from the introduction of mobile devices and wireless communications in the context of the Grid computing paradigm. We further propose an architecture for the realization of a Mobile Grid and investigate key design decisions and optimizations.","PeriodicalId":347028,"journal":{"name":"2007 15th IEEE Workshop on Local & Metropolitan Area Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114876169","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 : 2007-06-10DOI: 10.1109/LANMAN.2007.4295975
Chun-Yin Li, A. Wai, V. Li
In this paper, we investigate the integration of passive optical networks (PONs) with optical burst switched (OBS) networks. Owing to the decomposition of the operations between the PONs and OBS nodes, serious problems have been observed. One of them is data burst assembly problem. In some situations, burst assembly delay exceeding tens seconds may be required if the general purpose PON access schemes are used. To solve this problem, we propose to have the optical network units (ONUs) take over the burst assembly function from the OBS nodes. Large reduction of the burst assembly delay is obtained. Four ONU data burst scheduling schemes have also been investigated. We observe that a simple scheduling scheme is itself adequate in most situations.
{"title":"Optical burst switching with burst access mode passive optical networks","authors":"Chun-Yin Li, A. Wai, V. Li","doi":"10.1109/LANMAN.2007.4295975","DOIUrl":"https://doi.org/10.1109/LANMAN.2007.4295975","url":null,"abstract":"In this paper, we investigate the integration of passive optical networks (PONs) with optical burst switched (OBS) networks. Owing to the decomposition of the operations between the PONs and OBS nodes, serious problems have been observed. One of them is data burst assembly problem. In some situations, burst assembly delay exceeding tens seconds may be required if the general purpose PON access schemes are used. To solve this problem, we propose to have the optical network units (ONUs) take over the burst assembly function from the OBS nodes. Large reduction of the burst assembly delay is obtained. Four ONU data burst scheduling schemes have also been investigated. We observe that a simple scheduling scheme is itself adequate in most situations.","PeriodicalId":347028,"journal":{"name":"2007 15th IEEE Workshop on Local & Metropolitan Area Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114976973","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 : 2007-06-10DOI: 10.1109/LANMAN.2007.4295996
Michael Snow, J. Park
The design of the most commonly-used Internet and local area network protocols provide no way of verifying the sender of a packet is who it claims to be. A malicious host can easily launch an attack while pretending to be another host to avoid being discovered. To determine the identity of an attacker, an administrator can use traceback, a technique that determines the path of attack packets from the victim to the coordinator. Most traceback research has focused on IP and stepping-stone techniques and little has been conducted on the problem of data-link layer trace-back (DLT), the process of tracing frames from the network edge to the attack source. We propose a scheme called tagged-frame traceback (TRACK) that provides a secure, reliable DLT technique for Ethernet networks. TRACK defines processes for Ethernet switches and a centralized storage and lookup host. Simulation results indicate that TRACK provides accurate DLT operation while causing minimal impact on network and application performance.
{"title":"Link-Layer Traceback in Ethernet Networks","authors":"Michael Snow, J. Park","doi":"10.1109/LANMAN.2007.4295996","DOIUrl":"https://doi.org/10.1109/LANMAN.2007.4295996","url":null,"abstract":"The design of the most commonly-used Internet and local area network protocols provide no way of verifying the sender of a packet is who it claims to be. A malicious host can easily launch an attack while pretending to be another host to avoid being discovered. To determine the identity of an attacker, an administrator can use traceback, a technique that determines the path of attack packets from the victim to the coordinator. Most traceback research has focused on IP and stepping-stone techniques and little has been conducted on the problem of data-link layer trace-back (DLT), the process of tracing frames from the network edge to the attack source. We propose a scheme called tagged-frame traceback (TRACK) that provides a secure, reliable DLT technique for Ethernet networks. TRACK defines processes for Ethernet switches and a centralized storage and lookup host. Simulation results indicate that TRACK provides accurate DLT operation while causing minimal impact on network and application performance.","PeriodicalId":347028,"journal":{"name":"2007 15th IEEE Workshop on Local & Metropolitan Area Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123535273","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 : 2007-06-10DOI: 10.1109/LANMAN.2007.4295998
Zhijun Liu, David Lee
Due to the real time nature and presence information of instant messaging (IM) system, worms spread over IM networks more rapidly than Internet/E-mail worms. Modeling is an indispensable process for coping with them. Most of existing worm modeling techniques are based on deterministic biological epidemiology. Epidemic models only capture the expected worm behavior quantitatively and may not be adequate to model the early phase of worm propagation when the number of infected hosts is small. In this paper, we present a statistical branching process for modeling IM worms. By introducing stochastic variables for user response time in IM worm modeling, we are able to conduct more accurate and sophisticated analysis of worm's behaviors, especially for the early phase of worm propagation. The analysis provides a guideline on how to defend against IM worms.
{"title":"Coping with Instant Messaging Worms - Statistical Modeling and Analysis","authors":"Zhijun Liu, David Lee","doi":"10.1109/LANMAN.2007.4295998","DOIUrl":"https://doi.org/10.1109/LANMAN.2007.4295998","url":null,"abstract":"Due to the real time nature and presence information of instant messaging (IM) system, worms spread over IM networks more rapidly than Internet/E-mail worms. Modeling is an indispensable process for coping with them. Most of existing worm modeling techniques are based on deterministic biological epidemiology. Epidemic models only capture the expected worm behavior quantitatively and may not be adequate to model the early phase of worm propagation when the number of infected hosts is small. In this paper, we present a statistical branching process for modeling IM worms. By introducing stochastic variables for user response time in IM worm modeling, we are able to conduct more accurate and sophisticated analysis of worm's behaviors, especially for the early phase of worm propagation. The analysis provides a guideline on how to defend against IM worms.","PeriodicalId":347028,"journal":{"name":"2007 15th IEEE Workshop on Local & Metropolitan Area Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127415773","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 : 2007-06-10DOI: 10.1109/LANMAN.2007.4295985
A. Burnic, C. Spiegel, Alex VieBmann, Arjang Hessamian-Alinejad, Andreas Waadt, G. Bruck, P. Jung
Cooperation in wireless networks will facilitate a new dimension in the evolution of multimedia communications, setting out from the today's situation with a multitude of communication standards and radio interfaces both in the licensed and the unlicensed domain. In order to pave the way towards cooperative networks, the deployment of cognitive wireless solutions, which will form the communication platforms, will be a hey asset. In the future, we expect to see an increasingly flexible, ad-hoc utilization of the available spectrum in the unlicensed domain and a co-exsitence of communication standards in the licensed bands. In this communication, the authors will illustrate a platform based approach towards cognitive wireless communications. Also, three software defined radio concepts designed by the authors was presented, namely the HAWK (highly adaptable wireless kit), the FALCON (flexible access logic for communication networks), and the MUSTANG (multi-standard single chip transceiver for the next generation), finally, giving an outlook on their wireless optical communication device, termed ARGOS. HAWK, FALCON, MUSTANG and ARGOS form the basis of the authors' cognitive wireless platform, termed PROMETHEUS. The setup of PROMETHEUS and its functionality shall be illustrated.
{"title":"Designing Terminals and Infrastructure Components for Cognitive Wireless Networks","authors":"A. Burnic, C. Spiegel, Alex VieBmann, Arjang Hessamian-Alinejad, Andreas Waadt, G. Bruck, P. Jung","doi":"10.1109/LANMAN.2007.4295985","DOIUrl":"https://doi.org/10.1109/LANMAN.2007.4295985","url":null,"abstract":"Cooperation in wireless networks will facilitate a new dimension in the evolution of multimedia communications, setting out from the today's situation with a multitude of communication standards and radio interfaces both in the licensed and the unlicensed domain. In order to pave the way towards cooperative networks, the deployment of cognitive wireless solutions, which will form the communication platforms, will be a hey asset. In the future, we expect to see an increasingly flexible, ad-hoc utilization of the available spectrum in the unlicensed domain and a co-exsitence of communication standards in the licensed bands. In this communication, the authors will illustrate a platform based approach towards cognitive wireless communications. Also, three software defined radio concepts designed by the authors was presented, namely the HAWK (highly adaptable wireless kit), the FALCON (flexible access logic for communication networks), and the MUSTANG (multi-standard single chip transceiver for the next generation), finally, giving an outlook on their wireless optical communication device, termed ARGOS. HAWK, FALCON, MUSTANG and ARGOS form the basis of the authors' cognitive wireless platform, termed PROMETHEUS. The setup of PROMETHEUS and its functionality shall be illustrated.","PeriodicalId":347028,"journal":{"name":"2007 15th IEEE Workshop on Local & Metropolitan Area Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132943683","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 : 2007-06-10DOI: 10.1109/LANMAN.2007.4295976
K. Reichmann, P. Iannone
In this talk we will present an overview of upgrade paths for TDM passive optical networks. An experimental demonstration of a wavelength-enhanced GPON is also presented.
在本次演讲中，我们将概述TDM无源光网络的升级路径。最后给出了波长增强型GPON的实验演示。
{"title":"Wavelength-Enhanced Passive Optical Networks with Extended Reach","authors":"K. Reichmann, P. Iannone","doi":"10.1109/LANMAN.2007.4295976","DOIUrl":"https://doi.org/10.1109/LANMAN.2007.4295976","url":null,"abstract":"In this talk we will present an overview of upgrade paths for TDM passive optical networks. An experimental demonstration of a wavelength-enhanced GPON is also presented.","PeriodicalId":347028,"journal":{"name":"2007 15th IEEE Workshop on Local & Metropolitan Area Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121038274","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 : 2007-06-10DOI: 10.1109/LANMAN.2007.4295969
V. Subramanian, S. Kalyanaraman, K. Ramakrishnan
Broadband technologies have made multi-hop wireless communications a reality. Loss-prone multi-hop networks pose challenges to link and transport layer protocols. Wireless links need to export low link-latencies, high goodputs and low residual loss rates to effectively enable interactive applications. Current link protocols with high ARQ persistence incur high latencies that impair such applications. We propose LL-HARQ, a link protocol that meets these goals. However, under high and bursty loss rates even LL-HARQ exports a small residual loss rate that could accumulate over multiple hops. Since TCP-SACK cannot handle error rates greater than 5%, a transport protocol (LT-TCP) designed for loss tolerance can be used under such cases. We provide insights into the structuring of the building blocks and balance between error-protection functions at the two layers and examine the case for cross-layer co-operation. Finally, we demonstrate that the combination achieves improved end-end performance (delay, loss and goodput) over traditional approaches.
{"title":"Balancing Loss-Tolerance between Link and Transport Layers in Multi-Hop Wireless Networks","authors":"V. Subramanian, S. Kalyanaraman, K. Ramakrishnan","doi":"10.1109/LANMAN.2007.4295969","DOIUrl":"https://doi.org/10.1109/LANMAN.2007.4295969","url":null,"abstract":"Broadband technologies have made multi-hop wireless communications a reality. Loss-prone multi-hop networks pose challenges to link and transport layer protocols. Wireless links need to export low link-latencies, high goodputs and low residual loss rates to effectively enable interactive applications. Current link protocols with high ARQ persistence incur high latencies that impair such applications. We propose LL-HARQ, a link protocol that meets these goals. However, under high and bursty loss rates even LL-HARQ exports a small residual loss rate that could accumulate over multiple hops. Since TCP-SACK cannot handle error rates greater than 5%, a transport protocol (LT-TCP) designed for loss tolerance can be used under such cases. We provide insights into the structuring of the building blocks and balance between error-protection functions at the two layers and examine the case for cross-layer co-operation. Finally, we demonstrate that the combination achieves improved end-end performance (delay, loss and goodput) over traditional approaches.","PeriodicalId":347028,"journal":{"name":"2007 15th IEEE Workshop on Local & Metropolitan Area Networks","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121435811","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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