An index system for dynamic peer-to-peer network based on document usefulness

Peer-to-peer (P2P) systems are applied to cooperative working environments, but require more effective document sharing mechanisms, particularly, more efficient query processing. To achieve efficient query processing in the environment, we study a distributed indexing mechanism, normal direct indices (DIs), which are the key to reducing the number of queries and improving scalability over P2P networks. However, query processing with DIs cannot efficiently deal with an increase in the number of document categories because a DI holds the peer´s information, not the document information. Therefore, we propose an improved DI, query-based DIs (QDIs). We assume that the peer is relevant to the query terms that the peer sends. This assumption allows each peer with correct QDIs to forward the query messages to their destination. To validate the QDIs, we show experimental results on query processing with and without DIs and show the improvement in network performance.