纯Peer to Peer环境下有效的Top-k查询  

Efficient Top-k Query Processing in Pure Peer-to-Peer Network

作　　者：何盈捷[1] 王珊[1] 杜小勇[1] 

机构地区：[1]中国人民大学信息学院,北京100872

出　　处：《软件学报》2005年第4期540-552,共13页Journal of Software

基　　金：国家自然科学基金;国家高技术研究发展计划(863);国家重点基础研究发展规划(973);北京市科技计划重大项目~~

摘　　要：目前大多数的Peer-to-Peer(P2P)系统只支持基于文件标识的搜索,用户不能根据文件的内容进行搜索.Top-k查询被广泛地应用于搜索引擎中,获得了巨大的成功.可是,由于P2P系统是一个动态的、分散的系统,在纯的P2P环境下进行top-k查询是具有挑战性的.提出了一种基于直方图的分层top-k查询算法.首先,采用层次化的方法实现分布式的top-k查询,将结果的合并和排序分散到P2P网络中的各个节点上,充分利用了网络中的资源.其次,根据节点返回的结果为节点构建直方图,利用直方图估计节点可能的分数上限,对节点进行选择,提高了查询效率.实验证明,top-k查询提高了查询效果,而直方图则提高了查询效率.Most of the existing peer-to-peer (P2P) systems only support simple title-based search, and users cannot search the data based on their content. Top-k query is widely used in the search engine and gains great success. However, Processing top-k query in pure P2P network is very challenging because a P2P system is a dynamic and decentralized system. An efficient hierarchical top-k query processing algorithm based on histogram is proposed. First, a distributed query processing model for top-k query is proposed. It does top-k query in a hierarchical way. Ranking and merging of documents are distributed across the peers, which takes full advantage of the computing resource of the network. Next, a histogram is constructed for each peer according to the top k results returned by the peer, and used to estimate the possible upper bound of the score for the peer. By the histogram information, the most possible peers are selected to send the query, so as to greatly improve the search efficiency. Experimental results show that the top-k query improves the query effectiveness, and the histogram improves the query efficiency.

关 键 词：P2P网络 TOP-K查询 搜索 直方图 

分 类 号：TP311[自动化与计算机技术—计算机软件与理论]