热量敏感的众核芯片多播并行测试方法

为了解决芯片测试过程中功耗密度大造成的局部过热(简称"热斑")问题,提出一种热量敏感的多播并行测试方法.对众核芯片采用多播并行测试时面临的"热斑"问题进行分析,提出一种无"热斑"的多播测试路径生成算法;在温度容限内对生成的多条单类同构芯核多播测试路径进行并行优化,形成无"热斑"的快速并行测试方案,同时缩短了测试时间.实验结果表明,采用文中方法能够有效地避免多播并行测试时的"热斑",并使测试时间缩短近45%.     

基于源树的MPLS最小冲突路径多播算法

维护多播信息需要额外的硬件开销,多播体系结构缺乏可扩展性,限制了多播业务的发展。本文在多播中应用MPLS最小冲突路径算法,在分支节点的MPLS中加入多播信息表,实现基于源树的多播树构建,从而解决了MPLS多播中数据转发的标签分配问题,具有良好的扩展性。实验表明,利用MPLS最小冲突路径算法,起到了节约带宽和提高多播性能的作用。     

一种基于VxWorks的话音通信系统的原理及实现

Vxworks嵌入式实时操作系统在通信、网络、工业、消费电子、军事等领域都有广泛的应用。随着Internet上多媒体应用及技术的不断发展,网络通信在嵌入式实时系统中将占有越来越重要的地位。组播技术可以帮助用户节约宝贵的带宽资源,有效地解决单点发送多点接收的问题。本文论述了组播的相关概念及如何在VxWorks下实现音频IP组播通信。     

基于中间件技术的Twitter系统研究与实现

本文将中间件技术引入到Twitter系统结构中,设计并实现了一套可信任的Twitter解决方案,该方案包括以下几部分:首先将系统的消息类型划分为存储型消息和验证型消息,并针对这两种不同的消息类型提出了相应的处理机制;提出以星型结构为基础的系统架构,引入消息中间件层,用于处理应用服务器传递的信息,采用中间件的分层结构体系,可以平衡各前端应用节点的负载,提高系统的可靠性、可伸缩性和可扩展性,使承载大访问量的Twitter服务成为可能。     

一类不确定Lur'e奇异系统的可靠鲁棒H_∞跟踪控制(英文)

The problem of reliable robust H_∞tracking control for a class of uncertain Lur'e singular systems is studied.A practical and general failure model of actuator and sensor is considered by using convex polytopic uncertainties to describe control surface impairment.Some sufficient conditions are presented for the case of actuator,sensor and control surface failures in terms of linear matrix inequalities (LMIs).The resultant control systems are reliable in that they guarantee closed-loop system robust stability with H_∞performance and the output tracking the reference signal without steady-state error when all control components are operational as well as when some control components experience failures.Finally,a numerical example is given to show the effectiveness of the proposed methods.     

An efficient hybrid multicast transport protocol for collaborative virtual environment with networked haptic

In recent years, we have witnessed a growing interest in the synchronous collaboration based class of applications. Several techniques for collaborative virtual environments (CVE), haptic, audio and visual environments (C-HAVE) have been designed. However, several challenging issues remain to be resolved before CVE and C-HAVE become a common place. In this paper, we focus on applications that are based on closely coupled and highly synchronized haptic tasks that require a high-level of coordination among the participants. Four main protocols have been designed to resolve the synchronization issues in such environments: the synchronous collaboration transport protocol, the selective reliable transmission protocol, the reliable multicast transport protocol and the scalable reliable multicast. While these four protocols have shown good performance for CVE and C-HAVE class of applications, none of these protocols has been able to meet all of the basic CVE requirements, i.e., scalability, reliability, synchronization, and minimum delay. In this paper, we present a hybrid protocol that is able to satisfy all of the CVE and C-HAVE requirements and discuss its implementation and results in two tele-surgery applications. This work is partially supported by Grants from Canada Research Chair Program, NSERC, OIT/Ontario Distinguished Researcher Award, Early Research Award and ORNEC Research Grant.     

组播聚合中高效的可扩展组-树匹配算法

当网络中同时存在大量的的组播组的时候,IP组播的可扩展性问题变得非常突出.对组播聚合中的组播组-树的匹配算法进行了研究,提出了一种高效的可扩展的组播组-树匹配算法(SGTM算法).在确定组播组的匹配树过程中,通过将组播树按照其开销进行排序以及扩展处理,降低了在查找过程中所检查的组播树的数量,提高了聚合组播算法的执行速度.并引入了对组播聚合性能进行度量的参数,结果表明SGTM算法与传统的组播聚合算法相比在同等性能的情况下执行速度更快.     

DPVoD:基于P2P的视频点播体系结构

可扩展性和可靠性是视频点播系统大规模应用的关键,提出了一种P2P点播系统结构DPVoD.系统基于应用层组播,用户以订制的缓存为其他节点提供服务,并形成相对独立的共享并发流组播树,组播树之问根据拥有的视频数据的重合程度而建立不同的组邻居关系,以此为基础,采用多种机制来提高系统性能:组协同工作、父亲点选择策略、状态控制协议和失效恢复等.定义并分析了可能对系统性能有严重影响的结尾雪崩问题并提出解决方案.对系统基本性能进行了理论分析.仿真结果表明,在静态和动态环境中,DPVoD系统的并发流占用数和利用率、可靠性等性能均优于类似系统.     

一种无线传感器网络的节能路由算法

提出一种基于逆向多播树的路由算法,该算法依赖局部信息建立基于逆向多播树的路由拓扑结构。利用该算法对不同类型的传感器数据建立不同的路由策略并进行传输。实验测试表明,该路由算法能有效地减少网络通信量,并具有较好的节能性能。     

基于混合式分级流标签的IPv6组播通信

IPv6网络协议引入流标签概念,在路由器转发提供QoS支持。针对IPv6多媒体组播通信的需要,提出一种混合式流标签分级定义方案实现IPv6组播通信的QoS支持,在IPv6实验网上进行多媒体组播通信模拟测试,结果表明该方案能够提供满意的QoS支持。