一种基于工业无线网络的路由和资源分配算法

采用家族谱系的描述方法,提出了一种适用于复杂现场监测的工业无线传感器网络路由和通信资源分配算法.该算法利用无线传感器网络的广播特性,采用分层、分时和分频相结合的策略实现路由和通信资源的分配,具有条理清晰、实现简单的特点.仿真测试表明,该算法能够有效提高无线网络的通信效率,可靠性高,并具有良好的可扩展性.     

ad hoc网络AODV协议在Windows CE上的实现

为给无线网络的应用提供研究平台,用Windows CE模拟器平台和IEEE 802.11b无线网络接口搭建真实的移动网络环境,通过调用API和增加功能模块的方式实现ad hoc路由协议,使用模拟器编写相关应用程序,实现AODV(Ad hoc on-demand Distance Vector)路由算法模块. 对该模块进行初步的验证和测试,结果表明:所设计的路由协议不仅在1跳范围内具有良好的通信性能,而且具备多跳通信能力;可以按需建立路由并实时启动路由维护过程. 该路由协议的实现为编写其他ad hoc网络路由协议提供1种实用框架.     

自组织覆盖网络QoS组播动态路由优化研究

针对覆盖组播节点的动态特性,研究自组织覆盖网络带度和延时约束的组播动态路由问题,提出了动态覆盖组播路由算法AHMQ。组播树由目的节点驱动动态渐近形成,动态路由优化在通信过程中进行。协议是软状态的,仅要求节点维护局部状态信息,同时利用覆盖网络技术和无线媒质的广播能力,降低了网络负载,提高了重构能力。对算法进行了分析研究,通过实验验证了该算法具有较好的性能。     

基于神经网络的动态路由选择算法

在分析了网络中基于QoS组播路由问题的基础上,文章给出了基于Hopfield神经网络的动态路由选择算法的模型。仿真研究表明该算法具有良好的分布特性和智能决策能力,此方案不仅保证了带宽、端到端延时和延时抖动,优化了路由树的代价,而且有效地控制了算法的复杂性,是一种快速动态组播路由算法,能实现全局网络资源利用的优化,容易扩展到大型网络中应用。     

基于以太网的家庭网络中间件模型

基于以太网的软硬件环境,提出了家庭网络中间件模型。该模型由三个协议模块组成:DRTCP协议、DDCP协议及SHNMP协议。支持该协议模型的家庭网络中间件能够实现设备的动态配置、网络监控以及互操作。通过DRTCP协议,该模型能够保证在重负载时网络传输仍然具有良好的实时性。     

基于蚁群的无线传感器网络路由算法

针对无线传感器节点能量、通信能力及计算能力有限等特点,将蚁群算法应用于无线传感器网络,提出一种改进的蚁群路由算法,考虑了节点的能量、距离、通信半径和传输方向等参数.实验结果表明:该算法有效地减少了网络能量消耗、节点死亡数、路由跳数和数据传输的路径长度,延长了无线传感器网络的寿命,实现无线传感器网络在通信过程中快速、节能的路由。     

Ad hoc数据通信网络多播路由算法

文中提出了采用按需路由发现策略的Ad hoc数据通信网络多播路由算法。算法采用按需路由发现过程，动态更新路由信息和建立多播转发组。文中详细介绍了算法的实现过程。模拟实验显示算法在带宽较低、多播组成员数量变化较大的Ad hoc数据通信网络环境中，具有较好的可靠性和工作效率。     

一类专用网络中的动态路由选择协议*

在分析现有路由选择协议的基础上,设计了适用于一类专用网络的动态路由选择协议。该协议采用按需路由方式,利用该类专用网络的全连通性缩短初始通信延迟,通过度量链路延迟来确定最佳路由,通过邻接节点信息表的维护实现备份链路的管理,支持到目的节点的多重路由。原型系统实现表明,该协议简单、高效、高可靠和高可用,可以满足专用网络的需要。     

一种新型片上网络互连结构的仿真和实现

综合性能、硬件实现等方面考虑,提出一种基于片上网络的互连拓扑结构-层次化路由结构MLR(Multi-Layer Router).该结构通过层次化设计减小网络直径,具有良好的对称性和扩展性.网络建模仿真和硬件实现结果显示,在不同网络负载和不同IP核节点数的情况下,MLR与传统结构相比,在处理网络通信时,对于网络丢包率、通信延迟和网络吞吐量等网络性能参数均有最多50%-70%的提升;同时通过共享路由的方式,减少了超过20%的芯片面积和40%以上的动态功耗,有效降低了互连结构的硬件开销     

加权网络的交通动力学研究

提出一种综合考虑网络边权和节点空闲度的路由策略,该路由搜索策略具有一可调参数 ,应用该策略对BBV加权网络上的数据传输进行研究。通过大量的数值仿真发现,当 时,网络具有最大的通信能力、较小的平均传输时间和最小的网络负载。与基于局域边权信息的路由策略相比,该策略可以提高网络通信能力,在拥塞状态下减小网络负载。对于加权网络的拥塞控制具有一定指导意义。     

Moving routing protocols to the user space in MANET middleware

Mobile Ad Hoc Network (MANET) middleware must be aware of the underlying multi-hop topology to self-adapt and to improve its communication efficiency. For this reason, many approaches rely on specific cross-layer communications to interact with the network protocols in the kernel space. But these solutions break the strict layering of the network stack and hinder the portability of middleware and applications.The main argument of this paper is to move the routing protocols to the user space to simplify the development, testing, deployment and portability of middleware and applications. If routing is just another software component in the user space, cross-layering can be elegantly solved using advanced software engineering techniques like component frameworks and explicit APIs. As a consequence, a slight performance cost must be paid to achieve portability and easy deployment. But we will demonstrate that the performance obtained by a user-space routing protocol is satisfactory for a wide range of applications.We have implemented the unicast MANET OLSR protocol in Java (jOLSR) and, on top of it, we have created a novel overlay multicast protocol (OMOLSR). We have then integrated both routing protocols (jOLSR, OMOLSR) as software components in a well-known group communication toolkit (JGroups). Modifying the JGroups toolkit, we have devised a topology-aware group communication middleware for MANETs (MChannel). In our MChannel middleware, group membership is obtained directly from OMOLSR multicast trees and failure detection is obtained from jOLSR active probing. We have validated our approach in several real testbeds to demonstrate the feasibility and efficiency of our middleware.     

IP组播技术在SCADA监控系统中的应用

分析目前SCADA监控系统中的数据通信方式,得出采用IP组播通信方式的必要性。并设计一个可靠组播通信中间件,建立报文接收确认和报文重传机制,确保报文收发的可靠性,在SCADA系统的收到良好的效果。     

A Survey of Fault Management in Wireless Sensor Networks

Wireless sensor networks are resource-constrained self-organizing systems that are often deployed in inaccessible and inhospitable environments in order to collect data about some outside world phenomenon. For most sensor network applications, point-to-point reliability is not the main objective; instead, reliable event-of-interest delivery to the server needs to be guaranteed (possibly with a certain probability). The nature of communication in sensor networks is unpredictable and failure-prone, even more so than in regular wireless ad hoc networks. Therefore, it is essential to provide fault tolerant techniques for distributed sensor applications. Many recent studies in this area take drastically different approaches to addressing the fault tolerance issue in routing, transport and/or application layers. In this paper, we summarize and compare existing fault tolerant techniques to support sensor applications. We also discuss several interesting open research directions. Lilia Paradis is currently a graduate student in the Department of Mathematical and Computer Sciences, Colorado School of Mines. She is also part of the Toilers Ad Hoc Networking research group. She is interested in distributed communication protocols for wireless sensor networks. Qi Han received the PhD degree in computer science from the University of California, Irvine in 2005. She is currently an assistant professor in the Department of Mathematical and Computer Sciences, Colorado School of Mines. Her research interests include distributed systems, middleware, mobile and pervasive computing, systems support for sensor applications, and dynamic data management. She is specifically interested in developing adaptive middleware techniques for next generation distributed systems. She is a member of the IEEE and the ACM.     

移动自组网中基于内容的发布／订阅路由协议

移动AdHoc网络下的分布式应用开发面临较大挑战,因此引入基于内容的发布,订阅中间件具有重要意义。该文提出一种新的基于内容的路由协议。通过建立优化的动态组播格网,根据内容匹配的结果,只向匹配的订阅节点传播事件,而限制不必要的事件传播。实验结果表明,该协议能够较大地改善网络总代价,节省网络带宽,提高系统的扩展性和性能。     

分布式数据流查询处理的P2P中间件研究

随着Web的大规模应用,分布式数据流的数量迅速增长,其查询处理面临极大的挑战。该文开发了分布式数据流响应查询的P2P中间件原型,利用基于内容路由所提供的可扩展性、通信负载平衡及动态适应性等特性,能有效地处理相似查询,支持内积查询。模拟实验表明该索引机制能减少网络连接的计算资源,提高数据流查询处理效率。     

移动Ad hoc网络安全路由协议研究

移动Ad hoc网络是由一组移动终端组成的无线多跳自治系统,具有无中心、自组织、多跳路由、动态拓扑结构等特点。尽管有带宽受限等缺点,但无线Ad hoc网络具备灵活机动、组网迅速的优势,在军事通信、民用通信和各种临时通信中具有广阔的应用前景。近来其路由技术、QoS、安全性问题,尤其是路由协议的安全成为研究的热点。介绍了针对其路由协议的攻击,重点分析比较了典型的移动Ad hoc网络安全路由协议,最后指出下一步研究的方向。     

Optimizing content-based routers: posets and forests

Event-based systems are seen as good candidates for supporting distributed applications in dynamic and ubiquitous environments because they support decoupled and asynchronous one-to-many and many-to-many information dissemination. Event systems are widely used because asynchronous messaging provides a flexible alternative to RPC. They are typically implemented using an overlay network of routers. A content-based router forwards event messages based on filters that are installed by subscribers and other routers. This paper addresses the optimization of content-based routing tables organized using the covering relation and presents novel configurations for improving local and distributed operation. We present the poset-derived forest data structure and variants that perform considerably better under frequent filter additions and removals than existing data structures. The results offer a significant performance increase to currently known covering-based routing mechanisms. Sasu Tarkoma received his M.Sc. and Ph.Lic degrees in Computer Science from the University of Helsinki, Department of Computer Science. He has over 20 scientific publications and has also contributed to several books on mobile middleware. His research interests include distributed computing and middleware. Jaakko Kangasharju is a PhD student at the University of Helsinki and working as a researcher at the Helsinki Institute for Information Technology. His research is concentrated on XML messaging and processing in the mobile wireless environment. He has participated in related standardization efforts at the Object Management Group and the World Wide Web Consortium.     

Communication mechanisms in ecological network-based grid middleware for service emergence

Next generation grid systems are heading for globally collaborative, service-oriented and live information systems that exhibit a strong sense of automation. A collection of autonomous agents is searched, assembled, and coordinated in a grid middleware system to produce desirable grid services. An effective communication mechanism is vital to the effectiveness of the step to build a novel grid middleware system. In this study, we provide our grid middleware with a flexible communication solution to implement the complicated behaviors among different agents. We propose a transport mechanism of grid middleware, named as ecological network communication language (ENCL) and ecological network interaction protocol (ENIP) respectively from a low-level to a high-level implementation strategy of a communication mechanism. A series of experiments demonstrate that a service with some of the desired properties can emerge from interacting agents via the proposed solution.     

中间件技术在联机交易系统的运用与创新

本文论述了中间件技术在一个联机交易系统中得到了具体的运用,根据系统的特点,根据数据库访问及交易型中间件的特点,并未采用现成的中间件产品,而是自行设计并编写一个中间层软件。目标是能够解决系统需要的数据库访问、网络通讯报文操作以及统一的流程控制,便于系统的客户端多渠道连接和新业务流程添加。