The fair distribution of bandwidth to different connections is an important issue in high-speed networks. This is especially true in low-priority services where the bandwidth available for the low priority connections may be small and may vary rapidly. An example is the available bit rate (ABR) service in asynchronous transfer mode (ATM) networks. This study uses the ABR service to explore a scheme that achieves better fairness in bandwidth allocations. Traditional schemes fail to achieve desired bandwidth allocations, which are generally based on connection weights. In this paper, a new scheme called active fairness is proposed which substantially improves fairness in bandwidth allocations. Contrary to the one set of weights used in traditional schemes, active fairness maintains two sets of weights at each link. The first set is the same as that used in traditional schemes, which represents the relative bandwidth allocation desired out of the available bandwidth at the link. If these weights are used directly in bandwidth allocation, the actual proportion of the bandwidth utilized by an individual connection can deviate substantially due to factors such as the number of links traversed by the connection, its round trip proportion delay, etc. In order to take into account these factors, another set of weights is derived at each link, which is used in bandwidth allocation. Simulations with VCs traversing different numbers of hops have shown marked improvement in fairness.
在高速网络中，带宽的公平分配是一个重要的问题。在低优先级业务中尤其如此，因为低优先级连接的可用带宽可能很小，并且变化可能很快。以ATM (asynchronous transfer mode)网络中的ABR (available bit rate)业务为例。本研究利用ABR业务，探索一种更公平的频宽分配方案。传统的带宽分配方案通常基于连接权重，无法实现预期的带宽分配。本文提出了一种新的带宽分配方案——主动公平方案，该方案大大提高了带宽分配的公平性。与传统方案中使用的一组权值不同，主动公平性在每个链路上保持两组权值。第一组与传统方案中使用的相同，它表示在链路可用带宽中期望的相对带宽分配。如果在带宽分配中直接使用这些权重，则由于连接所穿越的链路数量、往返比例延迟等因素，单个连接所利用的带宽的实际比例可能会有很大偏差。为了考虑这些因素，在每条链路上导出另一组权重，用于带宽分配。vc遍历不同跳数的模拟显示了公平性的显著提高。
{"title":"Active fairness: improved fairness with dynamic VC weights and generalized fairness in the ATM ABR service","authors":"J. Chew, A. Gupta","doi":"10.1109/ATM.1999.786854","DOIUrl":"https://doi.org/10.1109/ATM.1999.786854","url":null,"abstract":"The fair distribution of bandwidth to different connections is an important issue in high-speed networks. This is especially true in low-priority services where the bandwidth available for the low priority connections may be small and may vary rapidly. An example is the available bit rate (ABR) service in asynchronous transfer mode (ATM) networks. This study uses the ABR service to explore a scheme that achieves better fairness in bandwidth allocations. Traditional schemes fail to achieve desired bandwidth allocations, which are generally based on connection weights. In this paper, a new scheme called active fairness is proposed which substantially improves fairness in bandwidth allocations. Contrary to the one set of weights used in traditional schemes, active fairness maintains two sets of weights at each link. The first set is the same as that used in traditional schemes, which represents the relative bandwidth allocation desired out of the available bandwidth at the link. If these weights are used directly in bandwidth allocation, the actual proportion of the bandwidth utilized by an individual connection can deviate substantially due to factors such as the number of links traversed by the connection, its round trip proportion delay, etc. In order to take into account these factors, another set of weights is derived at each link, which is used in bandwidth allocation. Simulations with VCs traversing different numbers of hops have shown marked improvement in fairness.","PeriodicalId":266412,"journal":{"name":"IEEE ATM Workshop '99 Proceedings (Cat. No. 99TH8462)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125638710","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}
P. Castelli, R. Garroppo, S. Giordano, L. Guida, M. Molina, S. Tartarelli
The work focuses on traffic characterization of the LAN-to-LAN interconnection service, which represents the first move toward broadband internetworking. The paper first describes the activities related to measurement sessions carried out over a 100 Mbit/s Ethernet link of the company intranet of CSELT (Centro Studi e Laboratori Telecomunicazioni), then it reports the analysis of the acquired data necessary to evaluate the statistical parameters to be used in the modeling process. Measurements cover a time period of about one month, and we propose a method to gain confidence about the significance of the statistical parameters computed from the collected traffic traces, in order to reduce the risk that the extracted statistical features depend on a particular measurement session. The last part of the work reports some simulation studies, aiming to infer the statistical features that have a major impact on queueing performance.
这项工作的重点是LAN-to-LAN互连业务的流量特性，它代表了向宽带互连网络的第一步。本文首先描述了在CSELT (Centro Studi e Laboratori Telecomunicazioni)公司内部网的100 Mbit/s以太网链路上进行的与测量会话相关的活动，然后报告了对评估建模过程中使用的统计参数所需的采集数据的分析。测量覆盖了大约一个月的时间段，我们提出了一种方法来获得从收集的流量轨迹计算的统计参数的显著性的置信度，以减少提取的统计特征依赖于特定测量会话的风险。工作的最后一部分报告了一些模拟研究，旨在推断对排队性能有重大影响的统计特征。
{"title":"Traffic characterization for an interconnection service of fast Ethernet LANs","authors":"P. Castelli, R. Garroppo, S. Giordano, L. Guida, M. Molina, S. Tartarelli","doi":"10.1109/ATM.1999.786902","DOIUrl":"https://doi.org/10.1109/ATM.1999.786902","url":null,"abstract":"The work focuses on traffic characterization of the LAN-to-LAN interconnection service, which represents the first move toward broadband internetworking. The paper first describes the activities related to measurement sessions carried out over a 100 Mbit/s Ethernet link of the company intranet of CSELT (Centro Studi e Laboratori Telecomunicazioni), then it reports the analysis of the acquired data necessary to evaluate the statistical parameters to be used in the modeling process. Measurements cover a time period of about one month, and we propose a method to gain confidence about the significance of the statistical parameters computed from the collected traffic traces, in order to reduce the risk that the extracted statistical features depend on a particular measurement session. The last part of the work reports some simulation studies, aiming to infer the statistical features that have a major impact on queueing performance.","PeriodicalId":266412,"journal":{"name":"IEEE ATM Workshop '99 Proceedings (Cat. No. 99TH8462)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116020791","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}
This paper describes a service provisioning policy for the GFR (guaranteed frame rate) service. The GFR enables provision of cost-effective ATM services for IP-based data communications. There are two implementation alternatives for the GFR, which are FIFO and per-VC queuing. It is difficult to provide consistent services when both schemes exist in a network, because they show different characteristics for TCP/IP traffic. Taking into account this issue, this paper discusses GFR service policy that is fair for all the users. In order to clarify GFR service characteristics, the performance of our developed FIFO-based GFR circuit is demonstrated. Then the relationship between fairness and charging system is discussed and a hybrid charging scheme is proposed.
{"title":"Service provisioning policy for FIFO-based GFR scheme","authors":"J. Tanaka, M. Goto, T. Ishihara","doi":"10.1109/ATM.1999.786771","DOIUrl":"https://doi.org/10.1109/ATM.1999.786771","url":null,"abstract":"This paper describes a service provisioning policy for the GFR (guaranteed frame rate) service. The GFR enables provision of cost-effective ATM services for IP-based data communications. There are two implementation alternatives for the GFR, which are FIFO and per-VC queuing. It is difficult to provide consistent services when both schemes exist in a network, because they show different characteristics for TCP/IP traffic. Taking into account this issue, this paper discusses GFR service policy that is fair for all the users. In order to clarify GFR service characteristics, the performance of our developed FIFO-based GFR circuit is demonstrated. Then the relationship between fairness and charging system is discussed and a hybrid charging scheme is proposed.","PeriodicalId":266412,"journal":{"name":"IEEE ATM Workshop '99 Proceedings (Cat. No. 99TH8462)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124681775","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}
In this paper, we look at some examples of how "IP meets ATM" and then discuss some of the recent advances in IP standards. For the remainder of the paper, we examine testing techniques used in three different scenarios: functional testing of a layer 2/layer 3 switching device; class of service (CoS) contract verification in an IP network; interworking testing of an IP/ATM access device.
{"title":"Testing techniques for next-generation IP networks","authors":"G. Nelson","doi":"10.1109/ATM.1999.786779","DOIUrl":"https://doi.org/10.1109/ATM.1999.786779","url":null,"abstract":"In this paper, we look at some examples of how \"IP meets ATM\" and then discuss some of the recent advances in IP standards. For the remainder of the paper, we examine testing techniques used in three different scenarios: functional testing of a layer 2/layer 3 switching device; class of service (CoS) contract verification in an IP network; interworking testing of an IP/ATM access device.","PeriodicalId":266412,"journal":{"name":"IEEE ATM Workshop '99 Proceedings (Cat. No. 99TH8462)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115075301","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}
This paper studies the optimal service schedule of CBR traffic when the server rate is modelled according to a Markov process. The CBR traffic is mixed with traffic of another session (interfering traffic) which might be either CBR or VBR (variable bit rate) or both. The CBR traffic can suffer a maximum delay of T. The scheduler must decide which session must be scheduled for service based on future server rate, estimated from the currently available information. The objective of this paper is to find an optimal time t/sub s/
{"title":"Optimal service schedule for CBR traffic in a high speed network","authors":"N. Sai, Shankaramma Shivaprasad","doi":"10.1109/ATM.1999.786903","DOIUrl":"https://doi.org/10.1109/ATM.1999.786903","url":null,"abstract":"This paper studies the optimal service schedule of CBR traffic when the server rate is modelled according to a Markov process. The CBR traffic is mixed with traffic of another session (interfering traffic) which might be either CBR or VBR (variable bit rate) or both. The CBR traffic can suffer a maximum delay of T. The scheduler must decide which session must be scheduled for service based on future server rate, estimated from the currently available information. The objective of this paper is to find an optimal time t/sub s/<T for switching the service from interfering traffic to CBR traffic. This switching of the scheduler from one traffic to another traffic takes into account the stochastic variation of the server rate. Three cases of variation of the source rate are considered, namely: (1) when the server rate is a constant; (2) when the server rate jumps randomly between two values; and (3) when the variation of server rate follows a diffusion process. In all three cases, this paper shows that there exists an optimal switching time t/sub s/ after which the low-priority CBR traffic can be scheduled for service. The maximum delay and the cell loss rate are determined.","PeriodicalId":266412,"journal":{"name":"IEEE ATM Workshop '99 Proceedings (Cat. No. 99TH8462)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128863427","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}
Recently, many self-healing algorithms have been proposed to achieve survivability requirements when a failure occurs in the network. The so-called, pre-assigned backup VP (virtual path) restoration algorithm has been proved to have a fast restoration from failure, but its success greatly depends on how the traffic is distributed and how the spare capacity is dimensioned over the network. In this paper, we address the problem of spare capacity resource control, in order to guarantee complete restoration, improving the survivability performance of the self-healing algorithm. Centralized and distributed controls are used as methods for backup VP assignment. The performance of each method and the management of spare resources are investigated by simulation. The results show that the centralized method has higher efficiency, in resource utilization, than the distributed one. Furthermore, the spare resource control can achieve good fairness performance in resource utilization.
{"title":"Spare resources control function enhanced self-healing algorithm","authors":"A. Greca, K. Nakagawa, C. Yamada","doi":"10.1109/ATM.1999.786889","DOIUrl":"https://doi.org/10.1109/ATM.1999.786889","url":null,"abstract":"Recently, many self-healing algorithms have been proposed to achieve survivability requirements when a failure occurs in the network. The so-called, pre-assigned backup VP (virtual path) restoration algorithm has been proved to have a fast restoration from failure, but its success greatly depends on how the traffic is distributed and how the spare capacity is dimensioned over the network. In this paper, we address the problem of spare capacity resource control, in order to guarantee complete restoration, improving the survivability performance of the self-healing algorithm. Centralized and distributed controls are used as methods for backup VP assignment. The performance of each method and the management of spare resources are investigated by simulation. The results show that the centralized method has higher efficiency, in resource utilization, than the distributed one. Furthermore, the spare resource control can achieve good fairness performance in resource utilization.","PeriodicalId":266412,"journal":{"name":"IEEE ATM Workshop '99 Proceedings (Cat. No. 99TH8462)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132798880","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}
AAL type 2 is expected to become a key technology for providing various services, mainly compressed voice, over widespread ATM networks. This paper clarifies VC (virtual channel) characteristics, i.e. ATM VC bearer (DBR and SBR) and traffic parameters (PCR and SCR), for multiplexing AAL type 2 connections, with changing in the number of AAL type 2 connections in a VC to apply AAL type 2 to actual services in ATM networks. The traffic parameters were numerically evaluated by computer simulation and the VC multiplexing effect was also evaluated using a simple connection admission control algorithm. We show the applicable domain where SBR VCs can be used instead of introducing AAL type 2 switches and re-multiplexing these VCs into larger DBR VCs. The results of this paper can be used to design a VC structure for AAL type 2 traffic in ATM networks.
{"title":"ATM network architecture for AAL type 2 traffic","authors":"H. Kusano, T. Ohba, K. Miyake","doi":"10.1109/ATM.1999.786882","DOIUrl":"https://doi.org/10.1109/ATM.1999.786882","url":null,"abstract":"AAL type 2 is expected to become a key technology for providing various services, mainly compressed voice, over widespread ATM networks. This paper clarifies VC (virtual channel) characteristics, i.e. ATM VC bearer (DBR and SBR) and traffic parameters (PCR and SCR), for multiplexing AAL type 2 connections, with changing in the number of AAL type 2 connections in a VC to apply AAL type 2 to actual services in ATM networks. The traffic parameters were numerically evaluated by computer simulation and the VC multiplexing effect was also evaluated using a simple connection admission control algorithm. We show the applicable domain where SBR VCs can be used instead of introducing AAL type 2 switches and re-multiplexing these VCs into larger DBR VCs. The results of this paper can be used to design a VC structure for AAL type 2 traffic in ATM networks.","PeriodicalId":266412,"journal":{"name":"IEEE ATM Workshop '99 Proceedings (Cat. No. 99TH8462)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115142059","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}
A. Arutaki, H. Ikeda, T. Aramaki, M. Honda, T. Amagai, K. Yamada, T. Nishida
The rapid growth of the Internet impacts ATM networks to be furnished with IP handling capability. This paper discusses networking issues for IP and ATM integration. First, it considers function allocation at the boundary of an ATM backbone network and the Internet. As a result, the paper explains the necessity of built-in IP handling capability in an ATM switching system, and summarizes functional requirements for the system architecture. According to the discussion, the authors propose a system architecture for IP/ATM integration in the ATM switching system. The implementation of the proposed architecture is evaluated, and the wire-speed IP handling capability in the ATM switch is confirmed.
{"title":"ATM and IP integration by built-in IP handling capability in an ATM switching system","authors":"A. Arutaki, H. Ikeda, T. Aramaki, M. Honda, T. Amagai, K. Yamada, T. Nishida","doi":"10.1109/ATM.1999.786849","DOIUrl":"https://doi.org/10.1109/ATM.1999.786849","url":null,"abstract":"The rapid growth of the Internet impacts ATM networks to be furnished with IP handling capability. This paper discusses networking issues for IP and ATM integration. First, it considers function allocation at the boundary of an ATM backbone network and the Internet. As a result, the paper explains the necessity of built-in IP handling capability in an ATM switching system, and summarizes functional requirements for the system architecture. According to the discussion, the authors propose a system architecture for IP/ATM integration in the ATM switching system. The implementation of the proposed architecture is evaluated, and the wire-speed IP handling capability in the ATM switch is confirmed.","PeriodicalId":266412,"journal":{"name":"IEEE ATM Workshop '99 Proceedings (Cat. No. 99TH8462)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116308234","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}
Already today, ATM networks are not only used in backbone configurations of corporate networks, but also to connect local area networks (LAN). Personal computers and workstations can be equipped with ATM interfaces, as well as other devices that require high transmission rates, i.e., video cameras. ATM encryption devices are required in order to guarantee data confidentiality during transmission. The ATM Forum has defined security specifications for this. This contribution presents the ATM encryption technology, the difficulty with synchronization, as well as its realizability. The described implementation uses SDH/SONET connections with 155 Mbit/s as network interfaces, VLSI components for the encryption algorithm, and FPGA modules for the management and control of the ATM encryption.
{"title":"ATM-encryption with 155 Mbit/s","authors":"S. Kuhn, C. Ruland, K. Wollenweber","doi":"10.1109/ATM.1999.786873","DOIUrl":"https://doi.org/10.1109/ATM.1999.786873","url":null,"abstract":"Already today, ATM networks are not only used in backbone configurations of corporate networks, but also to connect local area networks (LAN). Personal computers and workstations can be equipped with ATM interfaces, as well as other devices that require high transmission rates, i.e., video cameras. ATM encryption devices are required in order to guarantee data confidentiality during transmission. The ATM Forum has defined security specifications for this. This contribution presents the ATM encryption technology, the difficulty with synchronization, as well as its realizability. The described implementation uses SDH/SONET connections with 155 Mbit/s as network interfaces, VLSI components for the encryption algorithm, and FPGA modules for the management and control of the ATM encryption.","PeriodicalId":266412,"journal":{"name":"IEEE ATM Workshop '99 Proceedings (Cat. No. 99TH8462)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122247094","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}
Recently, a novel quasi-static routing scheme called path switching has been proposed for a large-scale ATM packet switch, and a Clos-like switching network called the cross-path switch was designed for its implementation. In principle, the cross-path switch can support both multicast and multirate traffic and now we add the capacity of supporting multimedia traffic in it. In this paper, we develop a model to study the performance guarantees in a cross-path switch. Based on this model, we derive a set of deterministic bounds on propagation delay as well as backlogs at the switch on a per-connection basis. The results show that due to the quasi-static nature of the routing scheme implemented at the central stage, data traffic always becomes more bursty after passing through the cross-path switch. This leads to the criteria for the design of the route assignment algorithm.
{"title":"Per-connection performance guarantees for cross-path ATM packet switch","authors":"M. Chan, P. P. To, T.T. Lee","doi":"10.1109/ATM.1999.786898","DOIUrl":"https://doi.org/10.1109/ATM.1999.786898","url":null,"abstract":"Recently, a novel quasi-static routing scheme called path switching has been proposed for a large-scale ATM packet switch, and a Clos-like switching network called the cross-path switch was designed for its implementation. In principle, the cross-path switch can support both multicast and multirate traffic and now we add the capacity of supporting multimedia traffic in it. In this paper, we develop a model to study the performance guarantees in a cross-path switch. Based on this model, we derive a set of deterministic bounds on propagation delay as well as backlogs at the switch on a per-connection basis. The results show that due to the quasi-static nature of the routing scheme implemented at the central stage, data traffic always becomes more bursty after passing through the cross-path switch. This leads to the criteria for the design of the route assignment algorithm.","PeriodicalId":266412,"journal":{"name":"IEEE ATM Workshop '99 Proceedings (Cat. No. 99TH8462)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130073710","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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