中文摘要：

结构化P2P系统固有的高度动态性，造成其自身结构的维护代价非常大，甚至影响到系统的可用性．针对这一问题，利用资源共享系统中用户行为的规律性，采用克隆节点的方法，提出一个新的基于用户行为的克隆节点协议（clone node protocol，CNP）来削减这种维护代价．在此基础上实现了一个基于CNP协议的Clone Node Chord系统（即CNChord），并提出了CNChord下的被动式克隆算法、快速定位算法、差异性push同步算法和优化维护算法．理论分析和实验结果表明，CNP可以有效地降低结构化P2P系统自身结构的维护代价，同时将系统的查询复杂度提高到了（1／2）O（lgN）．

英文摘要：

With highly dynamic characteristics, structured P2P system costs too much for maintenance of its structure, which may even affect its availability. In order to solve this problem, a novel clone node protocol （CNP） based on characteristics of user behaviors and method of node cloning has been put forward to cut down the maintenance cost. A Clone Node Chord system （CNChord） based on CNP has been developed, and passive cloning algorithm, fast locating algorithm, differences-push synchronization algorithm and optimal maintenance algorithm has been proposed for CNChord. Theoretical analysis and experimental results indicate that CNP can effectively reduce the maintenance cost of structure of structured P2P system and raises the query complexity up to （1/2）O（lg N）.