服务总线支持Pub-Sub模式的路由研究

近年来,随着电信行业业务应用的发展,对电信业务服务质量提出了更高的要求。面向服务的体系结构（SOA）提供面向业务的系统框架。采用SOA架构的电信业务系统能满足处理性能、稳定性、完整性及其智能化程度等因素上的高要求。本文以电信行业业务服务性能为目的,从SOA架构的核心基础设施企业服务总线（ESB）对服务路由的支持着眼,提供服务跨系统的Pub／Sub交互,在基础设施上满足服务性能需求,并应用到电信行业中。     

企业信息化中的多层次可靠消息传递体系研究

论文通过对普通企业生产营运业务特点的分析,概括出三种信息传递的需求。针对这些需求利用WeblogicJMS和IP多播/应答机制给出了四种解决方案,经实验性能测试后将其统一整合到一个较为完善的多层次可靠消息传递体系中,并在具体的工程项目中获得验证。     

Analysis of a CDN–P2P hybrid architecture for cost-effective streaming media distribution

To distribute video and audio data in real-time streaming mode, two different technologies – Content Distribution Network (CDN) and Peer-to-Peer (P2P) – have been proposed. However, both technologies have their own limitations: CDN servers are expensive to deploy and maintain, and consequently incur a cost for media providers and/or clients for server capacity reservation. On the other hand, a P2P-based architecture requires sufficient number of seed supplying peers to jumpstart the distribution process. Compared with a CDN server, a peer usually offers much lower out-bound streaming rate and hence multiple peers must jointly stream a media data to a requesting peer. Furthermore, it is not clear how to determine how much a peer should contribute back to the system after receiving the media data, in order to sustain the overall media distribution capacity.In this paper, we propose and analyze a novel hybrid architecture that integrates both CDN- and P2P-based streaming media distribution. The architecture is highly cost-effective: it significantly lowers the cost of CDN capacity reservation, without compromising the media quality delivered. In particular, we propose and compare different limited contribution policies for peers that request a media data, so that the streaming capacity of each peer can be exploited on a fair and limited basis. We present: (1) in-depth analysis of the proposed architecture under different contribution policies, and (2) extensive simulation results which validate the analysis. Our analytical and simulation results form a rigorous basis for the planning and dimensioning of the hybrid architecture.     

规则推理的人工神经网络实现

本文从神经网络与传统专家系统相结合的角度出发,提出的一种基于层次与或图的神经网络专家系统模型。ＢＰ网被用作规则记忆器,并通过源于层次与或图的二值化样本的训练实现知识的获取,而网络的多次正向传播式的应用则用来完成相应的层次推理工作。     

有环图下基于内容发布/订阅系统路由算法改进

针对最小路径权值路由算法在有环拓扑结构下不能适用于大规模发布/订阅系统的问题,本文提出了颜色属性的概念。通过对代理设置颜色属性,对原有算法进行了改进,不仅确保订阅者收到匹配事件、避免转发环路的形成,并且降低了消息处理代价。该算法可以适用于大规模发布/订阅系统。     

QRTP: A Middleware for Broadband Networks

Broadband networks, such as those based on Asynchronous Transfer Mode (ATM), provide large bandwidth and multiple services. An essential application area for broadband networks is multimedia systems. The development of multimedia applications, however, is currently lagging behind the advances in the network technology. Our approach to the problem of more effectively developing multimedia applications is to provide developers with a middleware that encompasses a set of broadband-specific services needed by multimedia applications, for instance virtual connection setup, bandwidth reservation and session synchronization. Our middleware, called the Queen's Real-time Transport Protocol (QRTP), is based on the Real-time Transport Protocol standard from the Internet Engineering Task Force. The paper discuses the design, implementation and evaluation of the QRTP middleware.     

一种新的基于事件面向服务的BAM系统设计研究*

研究了面向服务的业务活动监控(BAM)系统设计问题。在分析BAM的几类系统模型优缺点的基础上,立足于BAM系统的动态感知、协同工作和实时处理数据,采用事件驱动体系架构,提出了一种基于事件、面向服务的业务活动监控系统模型。该模型以总线的形式构建在企业原有的各个信息系统之上,采用事件作为模块之间基本的通信机制,并对该系统模型中关键技术的设计进行了详细分析。最后通过原型系统的实验表明,该设计方案有良好的应用效果,可以有效地提高模型的计算效率。     

基于可伸缩的分布式结构的通用WWW信息发布与管理平台

文中介绍了采用CORBA／DCOM组件管理代理和通用化的软件设计方案,建立了一种基于可伸缩的分布式结构的通用WWW信息发布与管理平台。对实现可伸缩和分布结构的软硬件系统结构模式,以及系统安全管理策略提出了解决方法。     

Multi-path continuous media streaming: what are the benefits?

Quality of service (QoS) in delivery of continuous media (CM) over the Internet is still relatively poor and inconsistent. Although many such applications can tolerate some degree of missing information, significant losses degrade an application’s QoS. In this paper, we investigate the potential benefits of mitigating this problem through the exploitation of multiple paths existing in the network between a set of senders and a receiver of CM. Our focus in this work is on providing a fundamental understanding of the benefits of using multiple paths to deliver CM over best-effort wide-area networks. Specifically, we consider pre-recorded CM applications and use the following metrics in evaluating the performance of multi-path streaming as compared to single-path streaming: (a) data loss rate, (b) conditional error burst length distribution, and (c) lag1-autocorrelation. The results of this work can be used in guiding the design of multi-path CM systems streaming data over best-effort wide-area networks.     

基于网络设备内部存储的流媒体数据分发模型

当前支撑流媒体内容分发的主要技术是CDN和P2P.然而,这两种技术并没有充分利用底层网络拓扑信息,没有考虑位于网络中心的交换设备存储.基于在网络设备中增加存储的思想,本文面向流媒体应用提出了一种新的分发模型-put/get模型.该模型将网络设备中的缓冲区作为数据分发的枢纽,能够将数据分发路径与网络拓扑结构较好地匹配,更容易实现网络资源利用率的最大化.模拟实验结果验证了该分发模型的有效性.     

一种新的非线性离散动态大系统递阶控制的神经网络方法发*

本文给出了一种新具有全集成化特征的,求解非线性动态大规模系统递阶控制问题（ＬＯＣＰ）的神经网络模型（ＬＨＣＮＮ）该神经网络具有结构简洁,紧凑,高效的特点,适合于动态大规模系统的实时优化控制。     

基于神经网络的一类大系统动态递阶优化方法

提出了一种用于求解离散时间大系统动态递阶优化问题的神经网络模型(LHONN),该网络以全集成化为特征:1)各子系统的动态方程嵌入相应的局部优化网络中,使得网络结构具有较低的维数,易于硬件实现;2)其上级协调网络和局部优化网络的求解过程同时进行,优化求解速度高,适宜于实时系统优化.     

Practical design of a proxy agent to facilitate adaptive video streaming service across wired/wireless networks

Thanks to the growing of the wireless networks, the video streaming application becomes a ubiquitous joyful service. In a wireless communication network environment, the service traffic spans across the wired and wireless domains. In this article, we propose a practical design of a proxy agent - SPONGE (Stream Pooler Over a Network Graded Environment) sitting between the wireless User Equipments (UEs) and the video streaming server to facilitate the adaptive video streaming service across wired/wireless networks. To make the wireless streaming service more efficient, an input video session would be encoded as multiple qualities of video streams so that UEs with a similar receiving condition can share streams with the same service quality via SPONGE. SPONGE can alleviate the direct load on the original stream broadcasting server. Meanwhile, it can make each UE get an adaptive streaming service according to the network conditions of the UE by a reduced network condition feedback latency. Our theoretical analysis and simulation results show that SPONGE can help wireless streaming users get a smooth and better playback quality by a quick and accurate reaction to the network condition.     

一种流媒体CDN的内容部分推送策略

在流媒体CDN中,采用“推拉”结合的流媒体内容分发方式可进一步减少客户的平均启动时间,降低网络资源的消耗,根据流媒体文件的部分访问特性给出了一种流媒体内容的部分推送策略,并利用源服务器统计的历史访问信息,提出了目的代理缓存服务器的一种随机选择算法。实验表明该策略及算法可提高系统性能。     

一类非线性大系统递阶优化的神经网络方法*

本文给出了一种求解一类非线性大系统递阶优化问题的神经网络模型,克服了非线性大系统优化中的对偶间隙与不可分性问题,并且该神经网络具有全集成化的特点,易于硬件实现,其协调网络和局部优化网络同步工作,具有很高的求解效率,适宜于系统实时优化应用。     

面向商品电子交易的一种层次结构通信中间件系统

针对大规模商品电子交易中交易引擎集中式竞价交易的应用要求,结合基于消息传递机制通信中间件的工作特点,提出了面向交易通信中间件系统的一种树状层次结构模型。分析并讨论了基于该模型的通信中间件系统的通信机制和工作特点。