CTO: Concept Tree Based Semantic Overlay for Pure Peer-to-Peer Information Retrieval

Inspired by how search behavior works in human society, we propose CTO, a self-organized semantic overlay based on concept tree for P2P IR infrastructure, which is efficient for full text search in pure P2P environment without any central control or powerful peer as hub node. Especially, CTO performs very well on searching the unpopular resources shared by a few peers. In our experiment, while searching for the scarce documents shared by the peers, CTO achieves about 80 % recall rate when the search covers less than 5 % peers in the overlay. The search latency of CTO is also very low, which is controlled in the range about 5~12 hops