中文摘要：

为了有效抑制P2P网络中节点的搭便车行为，本文在校园网中开展研究，深入研究了搭便车用户的行为特征，并分析其根本原因，将用户行为引入激励机制，提出一种基于用户行为的激励机制User Behavior based Incentive Mechanism（UBIM）并设计了其效用函数，在效用函数复杂度和效率之间找到了良好的折中。在此基础上，设计并实现了UBIM的原型系统B1TShare，经过长期的运行表明，UBIM在有效抑制搭便车行为的同时，能显著提高系统的查询命中率、热门资源分享率以及节点平均在线时长。

英文摘要：

In order to effectively inhibit the free - rider behavior of nodes in P2P network, the behavioral characteristics of free - rid- ing users were studied and the reason of free - rider was analyzed in campus network. By combining user behavior with incentive mech- anism, User Behavior Based Incentive Mechanism （UBIM） was proposed and its utility function was designed. A good compromise be- tween complexity and efl3ciency of the utility function were founded. On this basis, BITShare is designed to verify UBIM＇s effect. A long - term test shows that UBIM can effectively inhibit the free - rider behavior and at the same time can greatly improve queries hit ratio, popular resources shariw, ratio and nodes＇averaue online time.