Pub Date : 2002-11-17DOI: 10.1109/GLOCOM.2002.1188440
T. Ikenaga, Yoshinori Isozaki, Y. Hori, Y. Oie
The current Internet has a single class of service, i.e., best-effort service, whereas multimedia information is actually transmitted there. Recently, many researchers have focused on a mechanism to provide some quality of service (QoS) required for applications such as delay-sensitive ones. With such a mechanism, a real-time communication request is sent to a server, such as a policy server, that will try to find a path that meets the request's QoS requirement. If several available paths meet the requirement, the connection will be established on one of them. Otherwise, the request will be rejected. In all likelihood, though, delaying the path reservation to some extent if no available path meets the requirement, rather than immediately rejecting a request, will improve the blocking probability. We assume here that the communication can tolerate some initial setup delay, which we refer to as acceptable delay. Our major objective is to clarify whether or not the delay schemes are effective in improving the blocking probability. Therefore, we examine two schemes for managing buffered requests and two different network topologies, i.e., Mesh and ISP. Through an extensive simulation, we have found that the blocking probability can be improved even when a small acceptable delay and a small buffer size are assumed. In particular, we found that the scheme works well in actual network topologies such as an ISP model.
{"title":"Performance evaluation of delayed reservation schemes in server-based QoS management","authors":"T. Ikenaga, Yoshinori Isozaki, Y. Hori, Y. Oie","doi":"10.1109/GLOCOM.2002.1188440","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1188440","url":null,"abstract":"The current Internet has a single class of service, i.e., best-effort service, whereas multimedia information is actually transmitted there. Recently, many researchers have focused on a mechanism to provide some quality of service (QoS) required for applications such as delay-sensitive ones. With such a mechanism, a real-time communication request is sent to a server, such as a policy server, that will try to find a path that meets the request's QoS requirement. If several available paths meet the requirement, the connection will be established on one of them. Otherwise, the request will be rejected. In all likelihood, though, delaying the path reservation to some extent if no available path meets the requirement, rather than immediately rejecting a request, will improve the blocking probability. We assume here that the communication can tolerate some initial setup delay, which we refer to as acceptable delay. Our major objective is to clarify whether or not the delay schemes are effective in improving the blocking probability. Therefore, we examine two schemes for managing buffered requests and two different network topologies, i.e., Mesh and ISP. Through an extensive simulation, we have found that the blocking probability can be improved even when a small acceptable delay and a small buffer size are assumed. In particular, we found that the scheme works well in actual network topologies such as an ISP model.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121561233","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1189032
Younggoo Kwon, Yuguang Fang, H. Latchman
Development of efficient medium access control (MAC) protocols is a fundamental research issue in high-speed wireless local area networks (LANs). We focus on the throughput efficiency of medium access algorithms for high-speed wireless LANs which use carrier sense multiple access/collision avoidance (CSMA/CA). We propose an efficient distributed contention-based MAC protocol for wireless local area networks, namely, the fast collision resolution (FCR) algorithm, and show that the proposed FCR algorithm provides high throughput and low latency in wireless LANs. The performance of FCR algorithm is compared with that of the IEEE 802.11 MAC algorithm via extensive simulation studies. The results show that FCR algorithm achieves a significantly higher efficiency than the IEEE 802.11 MAC algorithm and is easy to implement in wireless LANs.
{"title":"Fast collision resolution (FCR) MAC algorithm for wireless local area networks","authors":"Younggoo Kwon, Yuguang Fang, H. Latchman","doi":"10.1109/GLOCOM.2002.1189032","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1189032","url":null,"abstract":"Development of efficient medium access control (MAC) protocols is a fundamental research issue in high-speed wireless local area networks (LANs). We focus on the throughput efficiency of medium access algorithms for high-speed wireless LANs which use carrier sense multiple access/collision avoidance (CSMA/CA). We propose an efficient distributed contention-based MAC protocol for wireless local area networks, namely, the fast collision resolution (FCR) algorithm, and show that the proposed FCR algorithm provides high throughput and low latency in wireless LANs. The performance of FCR algorithm is compared with that of the IEEE 802.11 MAC algorithm via extensive simulation studies. The results show that FCR algorithm achieves a significantly higher efficiency than the IEEE 802.11 MAC algorithm and is easy to implement in wireless LANs.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123843142","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1188209
D. Piazza, L. Milstein
We analyze the influence of mobility on downlink performance of a wireless communication system. We first summarize some previously obtained information theoretic results, followed by a review of multiuser diversity systems. Then we introduce several first-order Markov chain models for use with multiuser diversity scheduling algorithms, in order to obtain quantitative performance results. Finally we propose an improved scheduling algorithm and compare its performance against that of a known scheduling algorithm.
{"title":"Multiuser diversity-mobility tradeoff: modeling and performance analysis of a proportional fair scheduling","authors":"D. Piazza, L. Milstein","doi":"10.1109/GLOCOM.2002.1188209","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1188209","url":null,"abstract":"We analyze the influence of mobility on downlink performance of a wireless communication system. We first summarize some previously obtained information theoretic results, followed by a review of multiuser diversity systems. Then we introduce several first-order Markov chain models for use with multiuser diversity scheduling algorithms, in order to obtain quantitative performance results. Finally we propose an improved scheduling algorithm and compare its performance against that of a known scheduling algorithm.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122601179","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1188485
C. Wann, Yi-Ming Chen, Ming-Shiung Lee
We present a mobile location tracking method with non-line-of-sight (NLOS) error mitigation for network-based wireless location systems. Based on the reconstructed LOS time of arrival (TOA) results from NLOS propagation identification and correction, geometric location techniques are used to calculate the location estimate of a mobile station. General TOA geometric cases and positioning solutions are analyzed. The time sequence of location samples is processed by Kalman filtering for position tracking and velocity estimation. A post-Kalman filter smoothing method is also applied to improve the velocity estimation. It is shown that the location tracking error can be reduced by processing the reconstructed line-of-sight TOA measurements with Kalman filtering.
{"title":"Mobile location tracking with NLOS error mitigation","authors":"C. Wann, Yi-Ming Chen, Ming-Shiung Lee","doi":"10.1109/GLOCOM.2002.1188485","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1188485","url":null,"abstract":"We present a mobile location tracking method with non-line-of-sight (NLOS) error mitigation for network-based wireless location systems. Based on the reconstructed LOS time of arrival (TOA) results from NLOS propagation identification and correction, geometric location techniques are used to calculate the location estimate of a mobile station. General TOA geometric cases and positioning solutions are analyzed. The time sequence of location samples is processed by Kalman filtering for position tracking and velocity estimation. A post-Kalman filter smoothing method is also applied to improve the velocity estimation. It is shown that the location tracking error can be reduced by processing the reconstructed line-of-sight TOA measurements with Kalman filtering.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122759438","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1188506
C. Nguyen, D. Hoang, A. Symvonis
"Delayed-multicast" is a novel transmission technique which uses internal nodes in the transmission paths from the server to the clients to buffer data streams. The buffers are used to service later requests without having to start new streams from the server, thus bringing the benefits of traditional multicast without the constraint that all requests must be serviced at the same time. We describe our new scalable "delayed-multicast" framework and present an optimal resource allocation algorithm that minimizes the total bandwidth required to service a set of requests.
{"title":"Resource allocation for video-on-demand with \"delayed-multicast\" protocol","authors":"C. Nguyen, D. Hoang, A. Symvonis","doi":"10.1109/GLOCOM.2002.1188506","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1188506","url":null,"abstract":"\"Delayed-multicast\" is a novel transmission technique which uses internal nodes in the transmission paths from the server to the clients to buffer data streams. The buffers are used to service later requests without having to start new streams from the server, thus bringing the benefits of traditional multicast without the constraint that all requests must be serviced at the same time. We describe our new scalable \"delayed-multicast\" framework and present an optimal resource allocation algorithm that minimizes the total bandwidth required to service a set of requests.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122757643","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1188539
Chiung-Jang Chen, Li-Chun Wang
In this paper, we present a new hierarchical cell system with an underlaid TDD/CDMA microcell and overlaying FDD/CDMA macrocells. With an objective to exploit the underutilized FDD uplink capacity due to traffic asymmetry, the TDD/CDMA microcell is operated within the uplink frequency band of the overlaying FDD/CDMA macrocells. By jointly applying the proposed antenna arrays at the cell site and a new power ratio adjustment technique, we evaluate the outage probabilities of the macrocell and the microcell. From the simulation results, we demonstrate that the full capacity of the TDD/CDMA microcell can be obtained without degrading the performance of FDD/CDMA macrocells.
{"title":"A hierarchical TDD microcell/FDD macrocell CDMA system using antenna arrays and power ratio adjustments","authors":"Chiung-Jang Chen, Li-Chun Wang","doi":"10.1109/GLOCOM.2002.1188539","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1188539","url":null,"abstract":"In this paper, we present a new hierarchical cell system with an underlaid TDD/CDMA microcell and overlaying FDD/CDMA macrocells. With an objective to exploit the underutilized FDD uplink capacity due to traffic asymmetry, the TDD/CDMA microcell is operated within the uplink frequency band of the overlaying FDD/CDMA macrocells. By jointly applying the proposed antenna arrays at the cell site and a new power ratio adjustment technique, we evaluate the outage probabilities of the macrocell and the microcell. From the simulation results, we demonstrate that the full capacity of the TDD/CDMA microcell can be obtained without degrading the performance of FDD/CDMA macrocells.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122819893","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1188218
Liang Xu, Xuemin Shen, J. Mark
A dynamic fair scheduling scheme, named aggressive code-division generalized processor sharing (A-CDGPS) scheme, is proposed to guarantee quality of service (QoS) for multimedia traffic in the uplinks of direct-sequence wideband code division multiple access (CDMA) cellular networks. The scheme performs slot-by-slot fair scheduling of the physical channel rates in response to the variation of multimedia traffic rates, and maximizes the utilization of the 30-called soft capacity of the CDMA uplinks. With the A-CDGPS scheme, deterministic delay bounds for heterogeneous traffic are derived. Simulation results show that the A-CDGPS is able to guarantee the delay requirement for delay-sensitive traffic, assure the weighted fairness among all the users, and maximize the throughput of delay-insensitive traffic.
{"title":"Aggressive code-division generalized processor sharing for QoS guarantee in multimedia CDMA cellular networks","authors":"Liang Xu, Xuemin Shen, J. Mark","doi":"10.1109/GLOCOM.2002.1188218","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1188218","url":null,"abstract":"A dynamic fair scheduling scheme, named aggressive code-division generalized processor sharing (A-CDGPS) scheme, is proposed to guarantee quality of service (QoS) for multimedia traffic in the uplinks of direct-sequence wideband code division multiple access (CDMA) cellular networks. The scheme performs slot-by-slot fair scheduling of the physical channel rates in response to the variation of multimedia traffic rates, and maximizes the utilization of the 30-called soft capacity of the CDMA uplinks. With the A-CDGPS scheme, deterministic delay bounds for heterogeneous traffic are derived. Simulation results show that the A-CDGPS is able to guarantee the delay requirement for delay-sensitive traffic, assure the weighted fairness among all the users, and maximize the throughput of delay-insensitive traffic.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122843707","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1189073
A. Ram, L. Dasilva, S. Varadarajan
The paper compares VoATM and VoIP in terms of their suitability for carrying voice traffic over DSL. ATM is currently the preferred protocol due to its built-in QoS mechanisms. Through simulations, we show that IP QoS mechanisms can also be used to achieve comparable performance for voice traffic over DSL. Our performance metrics are the end-to-end delay of voice packets across the DSL access network and the bandwidth requirements of a voice call. We also propose an implicit signaling mechanism to provide admission control for individual voice calls over DSL. We implement a simulation model that uses our mechanism and perform simulations to verify its effectiveness We conclude that by incorporating appropriate QoS mechanisms and implicit signaling, it is possible to achieve performance for VoIP comparable to that provided by ATM. In this case, the ubiquity of IP makes it a very attractive candidate for future deployments of VoDSL.
{"title":"Assessment of voice over IP as a solution for voice over ADSL","authors":"A. Ram, L. Dasilva, S. Varadarajan","doi":"10.1109/GLOCOM.2002.1189073","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1189073","url":null,"abstract":"The paper compares VoATM and VoIP in terms of their suitability for carrying voice traffic over DSL. ATM is currently the preferred protocol due to its built-in QoS mechanisms. Through simulations, we show that IP QoS mechanisms can also be used to achieve comparable performance for voice traffic over DSL. Our performance metrics are the end-to-end delay of voice packets across the DSL access network and the bandwidth requirements of a voice call. We also propose an implicit signaling mechanism to provide admission control for individual voice calls over DSL. We implement a simulation model that uses our mechanism and perform simulations to verify its effectiveness We conclude that by incorporating appropriate QoS mechanisms and implicit signaling, it is possible to achieve performance for VoIP comparable to that provided by ATM. In this case, the ubiquity of IP makes it a very attractive candidate for future deployments of VoDSL.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"29 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131110055","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1189050
Woei-Luen Shyu, Cheng-Shong Wu, T. Hou
IP caching has been time-proven to be capable of offloading routing-lookup modules. However, in evaluating the performance of IP caching, the cache size is a dominant factor. In this paper, we propose a caching scheme, named aligned-prefix caching (APC). APC takes advantage of prefix caching to reduce the cache size requirement. However, APC requires a routing-lookup module that can indicate whether an aligned prefix is cacheable or not. Thus, we propose a marking scheme, named aligned-ancestor poisoning, for tree-based routing tables. Our trace-driven simulations show that aligned-24 prefix caching can reduce the cache size requirement by about 50%, compared with the conventional destination caching scheme.
{"title":"Multilevel aligned IP prefix caching based on singleton information","authors":"Woei-Luen Shyu, Cheng-Shong Wu, T. Hou","doi":"10.1109/GLOCOM.2002.1189050","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1189050","url":null,"abstract":"IP caching has been time-proven to be capable of offloading routing-lookup modules. However, in evaluating the performance of IP caching, the cache size is a dominant factor. In this paper, we propose a caching scheme, named aligned-prefix caching (APC). APC takes advantage of prefix caching to reduce the cache size requirement. However, APC requires a routing-lookup module that can indicate whether an aligned prefix is cacheable or not. Thus, we propose a marking scheme, named aligned-ancestor poisoning, for tree-based routing tables. Our trace-driven simulations show that aligned-24 prefix caching can reduce the cache size requirement by about 50%, compared with the conventional destination caching scheme.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131153990","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 : 2002-11-17DOI: 10.1109/GLOCOM.2002.1189141
Xiaojun Cao, Jikai Li, Yang Chen, C. Qiao
Optical burst switching (OBS) is a promising paradigm for the next-generation Internet infrastructure. We study the performance of TCP traffic in OBS networks and in particular, the effect of assembly algorithms on TCP traffic. We describe three assembly algorithms in this paper and compare them using the same TCP traffic input. The results show that the performance of the proposed adaptive-assembly-period (AAP) algorithm is better than that of the min-burstlength-max-assembly-period (MBMAP) algorithm and the fixed-assembly-period (FAP) algorithm in terms of goodput and data loss rate. The results also indicate that burst assembly mechanisms affect the behavior of TCP in that the assembled TCP traffic becomes smoother in the short term, and more suitable for transmission in optical networks.
{"title":"Assembling TCP/IP packets in optical burst switched networks","authors":"Xiaojun Cao, Jikai Li, Yang Chen, C. Qiao","doi":"10.1109/GLOCOM.2002.1189141","DOIUrl":"https://doi.org/10.1109/GLOCOM.2002.1189141","url":null,"abstract":"Optical burst switching (OBS) is a promising paradigm for the next-generation Internet infrastructure. We study the performance of TCP traffic in OBS networks and in particular, the effect of assembly algorithms on TCP traffic. We describe three assembly algorithms in this paper and compare them using the same TCP traffic input. The results show that the performance of the proposed adaptive-assembly-period (AAP) algorithm is better than that of the min-burstlength-max-assembly-period (MBMAP) algorithm and the fixed-assembly-period (FAP) algorithm in terms of goodput and data loss rate. The results also indicate that burst assembly mechanisms affect the behavior of TCP in that the assembled TCP traffic becomes smoother in the short term, and more suitable for transmission in optical networks.","PeriodicalId":415837,"journal":{"name":"Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121862370","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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