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On the stability of multicast flow aggregation in IP over optical network for IPTV delivery

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Chinese Optics Letters 2008年第8期6卷 553-557页

作者：罗萱金耀辉曾庆济孙卫强郭薇胡卫生 State Key Lab of Advanced Optical Communication Systems and networks Shanghai Jiao Tong University

The stable multicast flow aggregation （MFA） problem in internet protocol （IP） over optical network under the dynamical scenario is studied. Given an optical network topology, there is a set of head ends and access touters attached to the optical network, in which each head end can provide a set of programs （IP multicasting flows） and each access router requests a set of programs, we find a set of stable light-trees to accommodate the optimally aggregated multicast IP flows if the requests of access touters changed dynamically. We introduce a program correlation matrix to describe the preference of end users＇ requests. As the original MFA problem is NP-complete, a heuristic approach, named most correlated program first （MCPF）, is presented and compared with the extended least tree first （ELTF） algorithm which is topology- aware. Simulation results show that MCPF can achieve better performance than ELTF in terms of stability with negligible increment of network resource usage.

关键词： Agglomeration electric network topology Fiber optic networks Heuristic algorithms Heuristic programming Internet Mobile telecommunication systems Multicasting Nuclear propulsion Optical data processing Optical materials Routers topology Trees (mathematics)

IMPLICIT REPRESENTATION FOR THE MODELLING OF HYBRID DYNAMIC SYSTEMS

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Chinese Journal of Aeronautics 2000年第1期13卷 45-50页

作者：陆宇平 Automatic Control Department Nanjing Univ. Aeronauatics A. Nanjing 210016 China

Hybrid systems can be represented by a discrete event model interacting with a continuous model, and the interface by ideal switching components which modify the topology of a system at the switching time. This paper deals with the modelling of such systems using the bond graph approach. The paper shows the interest of the implicit representation: to derive a unique state equation with jumping parameters, to derive the implicit state equation with index of nilpotency one corresponding to each configuration, to analyze the properties of those models and to compute the discontinuity.

关键词： electric network topology Equations of state Mathematical models Matrix algebra Switches

Consensus Seeking for Discrete-time Multi-agent Systems with Communication Delay

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IEEE/CAA Journal of Automatica Sinica 2015年第2期2卷 151-157页

作者： Zhenhua Wang Juanjuan Xu Huanshui Zhang School of Control Science and Engineering Shandong University

This paper studies the consensus problem for discrete-time multi-agent systems of first-order in the presence of constant communication delay. Provided that the agent dynamics is unstable and the network topology is undirected, effects of two kinds of communication delays on consensus are investigated. When the relative information is affected by delay, we show that the effect of delay can be alleviated by using the historical input information in the protocol design. On the other hand, if the communication delay only influences the actually transmitted information, sufficient condition admitting any large yet bounded delay for consensus is obtained, and the delay in this case is allowed to be unknown and time-varying. Finally, simulation results are provided to demonstrate the effectiveness of the theoretical results. © 2014 Chinese Association of Automation.

关键词： electric network topology

Research and implementation of a new web cache strategy

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Journal of Southeast University(English Edition) 2004年第4期20卷 448-453页

作者：易法令谢长生韩德志蔡斌华中科技大学计算机科学与技术学院

This paper presented a new shared cache technique-the grouping cache, which could solve many invalid queries in the broadcast probe and the control bottleneck of the centralized web cache by dividing all cooperative caches into several groups according to their positions in the network topology. The technique has the following characteristics: The overhead of multi-cache query can be reduced efficiently by the cache grouping scheme; the compact summary of the cache directory can rapidly determine if a request exists in a cache within the group; the distribution algorithm based on the web-access logs can effectively balance the load among all the groups. The simulation test demonstrated that the grouping cache was more effective than any other existing shared cache techniques.

关键词： Bandwidth Broadcasting electric network topology HTTP Internet Schematic diagrams World Wide Web