一种结构化P2P协议中的负载均衡方法

提出一种适合于路由表大小为O(logN) 的结构化P2P协议的负载均衡方法,该方法采用负载感知的被动式路由表维护算法和路由算法提高轻载结点作为路由中继结点的概率,并通过一种缓存机制来降低承载热点文件的结点的请求负载.实验结果表明,在用户查询服从Zipf分布的环境下,该负载均衡方法可使系统达到较好的负载均衡.     

基于蚁群算法的P2P网络资源发现算法

Gossip协议是P2P网络的一种流行的资源发现算法,但它没有考虑寻找最低成本的资源。论文提出了基于蚁群算法的新的资源发现算法,在查找资源的同时,综合考虑路径载荷、延时等因素,找到综合费用最低的路径。仿真实验表明,该算法比Dijkstra算法解集的平均综合费用低10%左右,从而能更有效地利用网络资源。     

基于结构化P2P网络的CORBA交易服务

交易服务能够在分布式环境下为用户提供发现网络中服务的能力。文章提出了一种在CORBA环境下基于结构化P2P网络的交易服务结构（DHT-Trader），该体系结构不仅具有结构化P2P网络的可扩展性和健壮性，还支持类型相关查询，包括基于属性查询和语义查询。文章着重分析了类型相关查询和语义查询的难点．提出了在结构化P2P网络中实现类型相关查询和语义查询的解决方案。通过使用DHT-Trader，出口者可以为一个服务发布若干名字．进口者仅根据其中之一就可以得到服务以及该服务类型的所有子类型。     

一种新的基于非结构化P2P网络的语义覆盖网络

在经典的语义覆盖网络中,所有节点都处于对等地位,没有考虑节点间共享资源数量及相对位置的差异,这使网络中节点分组信息的维护与资源搜索成本较高。丈中分析了节点间共享资源数量及相对位置的差异对语义覆盖网络中节点分组信息的维护与资源搜索代价的影响,并在此基础上提出了一种新的基于非结构化P2P网络的语义覆盖网络。该结构利用P2P网络的拓扑匹配与区分索引技术有效减少了经典语义覆盖网络中节点分组信息的维护及资源搜索代价,提升了网络的整体性能。     

一种基于响应追踪的非结构化P2P资源查找机制

为了提高非结构化P2P中资源查找的效率,针对查找请求的关键字重复出现以及资源共享不平均的现象,提出了基于响应追踪的资源查找机制RTRSM (Response Tracing based Resource Searching Mechanism),对请求响应的内容以及响应的来源进行追踪,并记录历史信息,以此构建提示型资源查找。在查找请求转发阶段,依据查找请求与历史记录的相关程度,自适应地调整转发策略,在保证较高查找成功率的同时,降低查找代价,提高查找效率。仿真实验表明,基于响应追踪的资源查找机制RTRSM可扩展性较好,能以较小的开销扩展到较大规模的系统中去。仿真实验还表明,RTRSM能保证90%以上的查找成功率。与洪泛法相比,RTRSM能减少54.2%的平均消息数,减少56.4%的平均跳数;与SQR (Scalble Query Routing)相比能减少28.9%的平均消息数,减少6.4%的平均跳数。     

一种基于P2P的网格资源发现算法

为了解决网格技术中节点随机加入及资源动态共享的问题,采用了P2P与网格技术有机融合的方式,改进了网格的动态性和可扩展性,建立了基于P2P的网格资源体系结构模型,并提出了一种融合DHT和蚁群算法的资源发现算法.该算法能有效地提高P2P网格环境下的资源发现性能,可以准确可靠的进行信誉值高、综合费用低的分布式资源发现.     

DLRD：一种支持动态负载均衡的P2P网格资源发现机制

网格技术是分布式环境中资源共享和协同工作的有效手段,资源发现机制是网格技术中的关键问题.在深入分析目前网格中资源发现机制的基础上,提出了一种支持动态负载均衡的网格资源发现机制--DLRD,并给出了相应的实现算法.DLRD基于P2P实现完全分布式的动态资源发现,可以动态灵活地增加网格中的节点并在各个节点上实现资源的动态均衡注册和定位查找.     

一种基于Echord协议的网格资源发现方法

针对网格集中式的资源发现方法存在单点失效、负载均衡差等问题,提出利用P2P技术进行网格资源发现方法.该方法通过改进Chord协议的后继节点函数和finger表,提出Echord(Enhanced Chord)协议,结合Echord协议特点,将网格中的虚拟组织构建成环状拓扑结构.网格资源被描述成基于XML的RDF形式,并按照一定的资源部署算法被均衡地发布在网格节点上.给出了如何应用Echord协议进行网格资源发现的算法.理论分析和仿真实验结果表明,相比于基于Chord的网格资源发现方法,该方法能改善系统的平均查找长度、消息传播性能、资源随机查找成功率.     

P2P系统中一种负载均衡的超级节点选择策略

传统的分层P2P网络拓扑构造存在超级节点服务能力偏低的问题,特别是在对时延要求高的应用中,超级节点的服务能力偏低将不能满足应用的需求。本文研究一种超级节点负载均衡的层次化网络拓扑构造方法,该方法在选择超级节点时不仅考虑节点的容量还将节点的剩余负载作为重要参考指标。在同等条件下,本方法可提高网络吞吐量,减少网络流量开销,为P2P网络的大规模应用提供了实用基础。     

基于Gossip机制的自组织覆盖网络拓扑管理协议(英文)

Gossip-based protocols have attracted more and more attention because of their simplicity and reliability.They can be applied to large-scale overlays for solving problems such as topology management,information dissemination,and aggregation.However,previous works sample nodes by their indegrees,without considering the differences in capability among nodes,and result in losing global load balancing.This paper proposes a load balancing gossip protocol for self-organizing overlays-LBTMP(Load-Balancing Topology...     

CARD资源发现架构在无线传感网络中的性能研究

(西北工业大学计算机学院,陕西西安,710072)【摘要】CARD架构适用于大规模、高查询率、每次查询的数据传输量较小的Ad-hoc网络,它的核心目标是降低网络资源发现能耗,延长网络生命周期。文章首先介绍了CARD架构的结构;然后,建立了该架构的数学模型,该模型以无线传感器网络为目标场景,并推导出CARD架构的能耗和查询成功率与各个参数之间的函数关系;最后,根据该模型对CARD架构的能耗和查询成功率进行了理论分析,为CARD架构的参数选择提供了可靠的依据,并为对架构的进一步优化打下了坚实基础。     

A Scalable Peer-to-Peer Web Services Overlay for Semantic Discovery

The growing number of web services advocates distributed discovery infrastructures which are semantics-enabled. We introduce a novel approach for semantic discovery of web services in structured P2P-based （Peer-to-Peer） registries. We partition concepts into different CGs （Concept groups） and index these ordered concept sets in a two-phase semantic routing mechanism. Each node and query has one concept set as its unique ID. For each concept in the query, current node first route the query to a node with nodeID that shares a prefix as long as with the query, but a longer CG. Second, the query will be routed to a node sharing a longer prefix than that of the current node. Combining with semantic similarity calculation, our proposal guarantees that most existing services matching a query will be found with bounded costs in terms of number of nodes involved. The scalability and reliability of our approach are also confirmed through emulation tests.     

动态网格下的资源发现算法

网格中应用程序的运行需要获取一些满足特定条件的网格资源。文章提出了一种网格环境下动态资源的表示方法-矩阵表示法,同时研究了矩阵表示法下的资源的查找和更新的算法。该算法充分考虑了资源属性的动态性,由于矩阵计算不用操作资源的原始数据,从而提高了查找的效率,不仅能够进行精确匹配的查询也能进行范围查询。在路由查询时,只要参考本地信息就可给出准确的路由选择。矩阵表示资源还简化了动态资源的更新过程,使资源信息能够及时接近真实的网格环境。     

一种高效的无线Ad-Hoc网络自适应资源管理技术研究

本文针对无线Ad Hoc网络的高度动态性、网络拓扑动态变化、链路不稳定等问题,提出了一种无线网络资源管理技术.该技术通过探测邻居节点,然后无线资源进行动态划分设置请求优先级从而建立动态划分资源优先级机制.实验表明,提出的方法能够快速进行查询,有效提高了Ad-Hoc网络中资源发现的性能和系统的稳定性,在时延方面也有一定的提高.     

A Method for Resource and Service Discovery in MANETs

The paper presents a novel resource and service discovery mechanism for MANETs using Routing Intelligent Mobile Agents(RIMAs). RIMAs periodically collect routing, resource and service availability information and index the same in appropriate RIMA nodes. Every mobile node is close to atleast one RIMA node. The mobile node running an application in need of a resource or a service dispatches a Discovery agent to its nearest RIMA node. The index available at the RIMA node will guide the Discoverer agent to the resource or service node. Analysis of the method reveals the computational complexity to be of the order of square of number of RIMA nodes. Communication overheads are the product of number of generated agents, agent size and number of hops travelled by an agent. The method has been simulated and tested on MANETs of varying sizes from 50 to 800 nodes. Simulation snapshots and results show the proper working and success of the algorithm. Basavaraj Talwar is a Research Assistant at the Protocol Engineering & Technology Unit in Electrical Communication and Engineering department in Indian Institute of Science, Bangalore, India. He is research interests include Applications of mobile agents in MANETs and mobile commerce security. Prof. Pallapa Venkataram is the Chief Programming Executive of Protocol Engineering & Technology Unit, Electrical Communication and Engineering department in Indian Institute of Science, Bangalore, India. He has over 160 publications at various levels. His research interests include Protocol Engineering, Mobile Agents, Mobile Commerce, Wireless Networks, Mobile Computing, Artificial Intelligence. He is a senior member of IEEE and has received numerous awards and other fellowships for his contributions. Prof. Lalit M. Patnaik is currently associated with Computer Science and Automation department in Indian Institute of Science, Bangalore, India. He has currently over 400 publications at various levels. His research interests include Computer Architecture, Parallel & Distributed Computing, CAD of VLSI Systems, Real-Time Systems, Soft Computing, Engineering Applications of Information Technology, Mobile Computing, Computational Neuroscience. He is a fellow of IEEE and has received numerous awards and other fellowships for his contributions.     

An Adaptive Resource Management Architecture for Active Networks

This paper presents a framework for resource management in highly dynamic active networks. The goal is to allocate and manage node resources in an efficient way while ensuring effective utilization of network and supporting load balancing. The framework supports co-existence of active and non-active nodes and proposes a novel Directory Service (DS) architecture that can be used to discover the suitable active nodes in the Internet and for selecting the best network path (end-to-end) and reserving the resources along the selected path. Intranode and internode resource management are facilitated through the DS, while within an active node the framework implements a composite scheduling scheme to schedule both the CPU and bandwidth resources to resolve the combined resource scheduling problems. In addition, a flexible active node database system and a simple adaptive prediction technique have been introduced in order to resolve the challenging problem of determining the CPU requirements of the incoming packets.     

一种改进的静态资源优化利用路由算法

提出了一种基于遗传算法的静态资源优化利用路由算法,该算法在考虑网络资源消耗的基础上,以网络负载平衡为优化目标,从而达到合理利用网络资源,增强网络生存性的目的。最后给出了仿真实验结果,并对结果进行了分析。     

一种改进的非结构化P2P网络搜索方法

如何高效地搜索资源是P2P网络中最为关键的问题。非结构化的对等网络，一般以广播方式作为其搜索的基本策略，引发较大的网络流量，因此，提出改进的搜索策略，包括把节点划分为拥有丰富资源的核心节点和稀疏资源的边缘节点，并为每个节点引入朋友节点，模拟测试表明改进算法稳定有效，降低了网络开销。