电网统一视频监控平台分布式部署架构研究与实现

在提升视频监控信息资源共享利用水平的同时,电网统一视频监控平台系统及网络负载均不断提高。本文分析了电网统一视频监控平台集中式部署关键性能影响因素,并通过分布式部署解决了多用户并发访问、视频接入量扩大给系统带来高负载、大视频量问题,为系统的深化应用及后续扩大视频点接入提供了保障。     

面向分布式业务的可重构光网络资源调度机制研究

针对在光网络中为分布式并发业务提供定制服务的问题,提出了一种负载均衡的多源多路并行调度策略,将网络负载和应用负载均衡分担在不同的资源节点.通过仿真验证,与普通的单源单路最短路策略和多源多路最短路并行传输策略相比,该策略能够有效地降低分布式业务的阻塞率.以分布式服务GridFTP在可重构光网络实验床上的应用为例,通过实验验证了该策略的可行性和有效性.实验结果表明,综合考虑应用资源和网络资源的负载均衡,可以有效降低分布式业务在网格系统中的处理时间,提高系统性能.     

多模车载视频监控系统中负载均衡算法设计

为了提高车载视频监控系统的视频传输质量,本文基于排队论,利用多链路捆绑技术,设计了基于TD-SCDMA,WCDMA和CDMA2000的多模车载视频监控的负载均衡算法.该负载均衡算法以各个网卡在数据传输时的传输时延、信号强度、运营商因子和丢包率加权作为均衡因子,依次作为负载均衡时数据转发的依据.经实验测试,本算法能够充分利用增加用户卡来增加传输速率,并通过捆绑不同运营商的用户卡来提高数据传输的稳定性,并且该算法较常用的轮询算法的数据传输速率有了较大提高.     

基于C／S结构的远程数字视频监控系统

当前视频监控系统正逐步由模拟化走向数字化。随着视频压缩技术和网络技术的发展，开发新一代基于计算机网络和多媒体MPEG-4压缩算法的视频监控系统已成为整个行业技术发展的主要方向之。本提出并研究设计了一种分布式网络视频监控系统。该系统采用流行的分布式C／S架构对系统进行设计，并采用流媒体技术，通过IP多播技术，RTP／RTCP实时传送视频监控流。     

对象存储系统中基于监控的动态负载均衡方法

负载均衡在存储系统领域一直是研究的热点,但在分布式的对象存储系统中的应用与实现方面仍存在缺陷.针对对象存储系统中负载均衡方法大都依靠经验或有限的动态配置指导自适应算法进行、在负载再平衡过程中无法控制迁移节奏,算法实现复杂,未充分考虑存储节点实时负载状况等不足,提出了一种基于监控的动态负载均衡方法.该方法将监控系统引入对象存储系统,完成对各存储节点负载状况的实时感知;根据节点负荷、异构性等因素进行综合估计来触发迁移算法,避免了依靠经验及预设值指导算法执行;利用监控系统灵活的自定义事件触发机制和故障自动化处理机制,设计负载迁移策略,动态完成节点间的负载再平衡,降低算法实现复杂难度;使用监控系统动作执行过程中的多步操作顺序流控制完成一次一迁移,有效掌控负载迁移节奏.将该方法应用到自主研发的对象存储系统CSCloud进行验证的结果表明,该方法能及时获取集群中各节点的负载信息,并实现及时、准确的动态负载平衡,为对象存储系统和其他分布式存储系统实现负载均衡提供了新思路.     

无线监控服务资源提取算法

针对目前无线监控系统可控性、扩展性不足的问题,设计了一种能够进行大规模接入的分布式视频监控系统架构,提出了服务资源按类别先请求后提取、集中控制,监控终端集中管理的策略,并给出了数据资源、媒体资源的提取过程,最后通过服务器负载均衡算法和级联方案实现了接入容量扩展。实验结果表明,采用该算法的系统响应时间可以有效降低58%左右,最高能同时处理上万个监控前端服务请求。     

军事禁区安全管理中网络视频监控技术的优势

网络视频监控技术以其便捷接入、高稳定性以及灵活扩展能力,广泛应用于行业治安视频监控系统建设中。它不但可构建低成本、分布式,网络化的军事禁区监控体系,而且还能大大提高军事禁区的监控和管理水平。本文介绍了网络视频监控技术在军事禁区网络视频监控中的作用,并阐述了传统的视频监控技术中存在的问题,及网络视频监控技术在军事禁区视监控中的优势。     

P2P分布式域名服务特性的实验研究

域名服务作为互联网中的基本应用,除了实现网络和主机域名到网络IP地址的转换功能之外,还兼负主机属性查询、负载均衡、资源搜索和资源定位等功能.基于P2P的分布式技术具有良好的负载均衡和鲁棒性,文章对于P2P技术在传统DNS服务器上的分布式域名服务系统的应用进行研究.     

公用无线局域网的负载均衡策略

无线局域网与GPRS结合而成的公用无线局域网,是一种覆盖全球的宽带移动通信网,负载均衡策略是其中的一项关键技术.本文首先提出基于接入控制器(AC)的集中式负载均衡策略(CLBAC)以提高网络安全性,然后提出分布式负载均衡策略(DLB):各用户在接入网络的时侯,首先采用虚拟的分布式协调功能(VDCF)预测各小区的实时负载,然后接入负载最轻的小区.与集中式负载均衡策略比较,分布式负载均衡策略在网络资源开销和安全性等方面具有明显优势.仿真结果表明:VDCF算法预测小区负载快捷准确.     

基于势力场博弈的无线网络视频流速率控制模型

多媒体通信中如何对视频流量速率进行高效公平分配是提升无线网络性能的重要手段.应用势力场博弈模型来研究无线网络视频流速率分配机制,根据视频流特性建立了基于流量信噪比和流量速率为参数的势力场效用函数,提出了基于势力场博弈的无线网络视频流速率控制模型.证明了模型的纳什均衡存在性及唯一性,并提出了势力场博弈模型纳什均衡的分布式求解算法.数值仿真验证了势力场博弈的纳什均衡存在性,仿真结果表明了提出的模型能保证不同视频流量间公平的速率分配,且由于提出的算法执行方式是分布式的,能有效减轻网络的负载.     

分布式VoD系统的分级存储调度

提出了一种适于大规模分布式ＶｏＤ系统的分级存储调度算法。该算法建立在多队列的排队模型之上,使用上系统均衡方法及基于优先级的缓冲区管理算法,并提供了迁移等待时间的计算方法。通过仿真实验给出了缓冲区大小与业务量和节目驻留时间的关系,为ＶｏＤ分级存储系统的设计提供了依据。     

代理集群的负载均衡系统的设计与实现

为了提高代理集群系统的整体性能,提高代理集群的效率,基于分布式计算领域已经较为成熟的负载均衡算法的研究成果,以及目前流行的服务器流量均衡策略,设计了一种针对代理集群这一应用背景的负载均衡策略系统,完成了系统结构和负载均衡策略的实现,并进行了性能测试。     

Efficient distributed power control for cellular mobile systems

Various distributed carrier-to-interference (C/I) balancing procedures have been developed to cope with implementational drawbacks of centralized power-control schemes. However, it would be inevitable for these distributed schemes to lose some system performance compared to a centralized one since they control their power level based on only the local C/I measurements. An efficient distributed power-control (DPC) scheme is proposed to maximize the system performance. A distributed C/I balancing algorithm is suggested, which converges fast and is robust to C/I estimation errors. A simple instability detection rule is also suggested to accelerate the balancing phase of DPC schemes. Numerical results indicate that our algorithm achieves improvements in terms of the outage probability as well as the algorithm speed. Robustness to the C/I measurement errors is also explored     

分布式视频编码中的边信息优化算法*

在分布式视频编码中的运动补偿插值算法通常采用正方形分块方案,然而考虑到视频中物体的运动和复杂的图像纹理结构,仅采用正方形分块不能得到优异的匹配效果.因此在基于小波域的分布式视频编码系统基础上,采用非规则分块方案来提取物体的边缘信息,从而提高运动估计时的匹配精度.实验结果表明,该方案在一定程度上能提高边信息质量.     

Data Allocation and Dynamic Load Balancing for Distributed Video Storage Server

In this paper, a novel initial videos allocation scheme and a dynamic load balancing strategy are proposed for a distributed video storage server in order to increase the availability and reduce operation cost. The initial allocation scheme determines the allocation of video replicas on the servers to achieve static load balance and to obtain a configuration for efficient dynamic load adjustment. From the simulation results, the proposed load shifting algorithm can reduce up to 50% request fail rate if compared with the same initialization algorithm without load shifting. The proposed initial allocation with load shifting also reduces 25% to 60% request fail rate from the least load first initial allocation scheme with load shifting, 5% to 10% request fail rate and 5% to 25% the number of shifting steps from the DASD dancing method. Moreover, a prototype is implemented on Windows NT to examine the correctness and practicability of the proposed schemes.     

A dynamic load balancing algorithm for Quality of Service and mobility management in next generation home networks

Heterogeneity of connection technologies and nodes mobility open new challenges in home networks control strategies. Moreover, user’s needs are changing towards applications requiring high transmission speeds such as 3D gaming, enhanced interactivity and high definition video. Each of those applications puts several constraints on the network capabilities to guarantee requirements on the Quality of Service. In this paper we introduce an innovative concept based on fast load balancing algorithm operating on top of a convergence layer, in order to rapidly react to network changes and contemporaneously to satisfy strict application demands. We formulated the load balancing problem as a Multi-Commodity Flow and resolved it with a column generation approach using Lagrangian Relaxation and Dijkstra algorithm. The load balancing problem computational complexity is decreased with respect to state of the art load balancing solutions based on linear programming techniques. Proof of concept simulation results are reported.     

A fully distributed power control algorithm for cellular mobilesystems

Several distributed power control algorithms that can achieve carrier-to-interference ratio (CIR) balancing with probability one have been proposed previously for cellular mobile systems. In these algorithms, only local information is used to adjust transmitting power. However, a normalization procedure is required in each iteration to determine transmitting power and, thus, these algorithms are not fully distributed. In this paper, we present a distributed power control algorithm which does not need the normalization procedure. We show that the proposed algorithm can achieve CIR balancing with probability one. Moreover, numerical results reveal our proposed scheme performs better than the algorithm presented in Grandhi et al. [1994]. The excellent performance and the fully distributed property make our proposed algorithm a good choice for cellular mobile systems     

An efficient clustering and load balancing of distributed cloud data centers using graph theory

The prime focus of the Cloud Service Providers is enhancing the service delivery performance of the distributed cloud data centers. The clustering and load balancing of distributed cloud data centers have significant impact on its service delivery performance. Hence, this paper models distributed cloud data center environment as a network graph and proposes a two‐phase cluster‐based load balancing (CLB) algorithm based on a graph model. The first phase proposes a Cloud Data Center Clustering algorithm to cluster the distributed cloud data centers based on their proximity. The second phase proposes a Client‐Cluster Assignment algorithm to perform uniform distribution of the client requests across the clusters to enable load balancing. To assess the performance, the proposed algorithms are compared with other K‐constrained graph‐based clustering algorithms namely, graph‐based K‐means and K‐spanning tree algorithms on a simulated distributed cloud data center environment. The experimental results reveal that the proposed CLB algorithm outperforms the compared algorithms in terms of the average clustering time, load distribution, and fairness index and hence improves the service delivery performance of the distributed cloud data centers.     

Spectrum Load Balancing for Medium Access in Cognitive Radio Systems

In this work, the problem of spectrum allocation in cognitive radios is shown to be similar to the load balancing problem in distributed computer systems. Spectrum load balancing (SLB) algorithm based on the non-cooperative load balancing problem in computers is proposed, and is applied to a cognitive radio system. The capability of SLB to support QoS in the presence of other competing cognitive networks is evaluated via simulations and compared with the existing spectrum load smoothing (SLS) algorithm. SLB is more efficient than SLS and it provides a Nash equilibrium.