Recently, peer-to-peer （P2P） search technique has become popular in the Web as an alternative to centralized search due to its high scalability and low deployment-cost. However, P2P search systems are known to suffe...Recently, peer-to-peer （P2P） search technique has become popular in the Web as an alternative to centralized search due to its high scalability and low deployment-cost. However, P2P search systems are known to suffer from the problem of peer dynamics, such as frequent node join/leave and document changes, which cause serious performance degradation. This paper presents the architecture of a P2P search system that supports full-text search in an overlay network with peer dynamics. This architecture, namely HAPS, consists of two layers of peers. The upper layer is a DHT （distributed hash table） network interconnected by some super peers （which we refer to as hubs）. Each hub maintains distributed data structures called search directories, which could be used to guide the query and to control the search cost. The bottom layer consists of clusters of ordinary peers （called providers）, which can receive queries and return relevant results. Extensive experimental results indicate that HAPS can perform searches effectively and efficiently. In addition, the performance comparison illustrates that HAPS outperforms a fiat structured system and a hierarchical unstructured system in the environment with peer dynamics.展开更多
P2P(peer to peer)网络中,节点的自私行为极大地降低了系统的可用性.基于债务关系的文件交换网络,构建了一种促进合作的激励机制.同时,该机制保证了文件交换的公平性.激励机制的关键在于DHT(distributed hash table)网络邻居有限的固有...P2P(peer to peer)网络中,节点的自私行为极大地降低了系统的可用性.基于债务关系的文件交换网络,构建了一种促进合作的激励机制.同时,该机制保证了文件交换的公平性.激励机制的关键在于DHT(distributed hash table)网络邻居有限的固有特征,因而节点间的交互易于形成重复博弈.DFFE(debt relationship based fair file exchange in DHT network)协议只需维护很少的本地节点交互信息,协议开销小、网络扩展性好.网络路由采用基于一跳信息的贪婪算法.理性节点间的博弈存在纳什均衡,其策略选择的近似算法具有渐进收敛性.仿真实验表明了激励机制的有效性和在动态网络中性能的稳定性.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant Nos. 60803003,60970124,60903038the Science and Technology Projects of Zhejiang Province under Grant No. 2008C14G2010007
文摘Recently, peer-to-peer （P2P） search technique has become popular in the Web as an alternative to centralized search due to its high scalability and low deployment-cost. However, P2P search systems are known to suffer from the problem of peer dynamics, such as frequent node join/leave and document changes, which cause serious performance degradation. This paper presents the architecture of a P2P search system that supports full-text search in an overlay network with peer dynamics. This architecture, namely HAPS, consists of two layers of peers. The upper layer is a DHT （distributed hash table） network interconnected by some super peers （which we refer to as hubs）. Each hub maintains distributed data structures called search directories, which could be used to guide the query and to control the search cost. The bottom layer consists of clusters of ordinary peers （called providers）, which can receive queries and return relevant results. Extensive experimental results indicate that HAPS can perform searches effectively and efficiently. In addition, the performance comparison illustrates that HAPS outperforms a fiat structured system and a hierarchical unstructured system in the environment with peer dynamics.
文摘P2P(peer to peer)网络中,节点的自私行为极大地降低了系统的可用性.基于债务关系的文件交换网络,构建了一种促进合作的激励机制.同时,该机制保证了文件交换的公平性.激励机制的关键在于DHT(distributed hash table)网络邻居有限的固有特征,因而节点间的交互易于形成重复博弈.DFFE(debt relationship based fair file exchange in DHT network)协议只需维护很少的本地节点交互信息,协议开销小、网络扩展性好.网络路由采用基于一跳信息的贪婪算法.理性节点间的博弈存在纳什均衡,其策略选择的近似算法具有渐进收敛性.仿真实验表明了激励机制的有效性和在动态网络中性能的稳定性.
基金the National Natural Science Foundation of China under Grant Nos.60673167 90412011 (国家自然科学基金)the National Basic Research Program of China under Grant No.2005CB321801 (国家重点基础研究发展计划(973))
文摘基于网络资源的"成长性"、"自治性"和"多样性",近年来,人们提出以通用DHT(distributed Hash table)信息服务的形式实现网络资源信息的发布和查询.然而,现有的资源信息服务在通用性、易用性和自适应性等方面仍存在不足.针对虚拟计算环境iVCE(Internet-based virtual computingen vironment)的资源聚合需求,提出构建可扩展的分布式资源信息服务SDIRIS(scalable distributed resource information service).首先,提出采用自适应DHT(adaptive FissionE,简称A-FissionE)底层架构,以对上层应用透明的方式适应不同的系统规模和稳定性;其次,基于自适应DHT提出高效的多属性区间搜索算法(multiple-attribute range FissionE,简称MR-FissionE).理论分析和模拟结果表明,SDIRIS能够高效地实现资源信息的发布与查询功能.
