语义对等网构造及搜索机制研究

对等网文件共享系统能否成功极大地取决于搜索机制的多样性和扩展性。当前支持分布式Hash表(DHT)功能的结构化系统(如CAN)易扩展但不能有效地支持部分匹配的查询，而基于扩散的非结构化系统(如Gnutella)支持多样化查询但不易扩展。提出了一种新的对等网体系结构。基于CAN构造的pGroup介于结构化和非结构化之间：结点根据内容的类别自组织在一起，具有相同类别的结点相互关联构成语义对等网(semantic peer-to-peer networks，SPNs)。针对不同的查询行为，提出了相应的搜索算法。实验表明，pGroup比Gnutella的扩展性好，搜索效率高。

Study on Construction and Searching of Semantic Peer-to-Peer Networks

The success of P2P file sharing system highly depends on the scalability and versatility of its search mechanism Existing structured P2P networks (such as CAN) supporting distributed Hash table (DHT) functionality are scalable but they can't support partial match queries effectively On the opposite, unstructured P2P networks (such as Gnutella) rely on flooding for search, thus supporting partial match queries, but such flooding does not make the systems scalable A new architecture for P2P networks is proposed Based on content addressable networks (CAN), a hybrid scheme called pGroup for building semantic peer to peer networks (SPNs) is presented where nodes with the same classes of contents are connected to each other According to the different querying, corresponding search algorithms are also proposed As is shown by experiments, scalability and search efficiency are improved greatly compared with Gnutella