  Peer-to-peer (P2P) networks establish loosely coupled application-level
overlays on top of the Internet to facilitate efficient sharing of resources.
It can be roughly classified as either structured or unstructured networks.
Without stringent constraints over the network topology, unstructured P2P
networks can be constructed very efficiently and are therefore considered
suitable to the Internet environment. However, the random search strategies
adopted by these networks usually perform poorly with a large network size. To
enhance the search performance in unstructured P2P networks through exploiting
users' common interest patterns captured within a probability-theoretic
framework termed the user interest model (UIM). A search protocol and a routing
table updating protocol are further proposed in order to expedite the search
process through self organizing the P2P network into a small world. Both
theoretical and experimental analyses are conducted and demonstrated the
effectiveness and efficiency of the approach.
