Query transformation is a serious hurdle on semantic peer-to-peer environment. Forinteroperability between peers, queries sent from a source peer have to be efficiently transformed to be understandable to potential peers processing the queries. However, the problem is that thetransformed queries might lose some information from the original one, as continuously traveling along peer-to-peer networks. We mainly consider two factors; i) number of transformations and ii) quality of ontology alignment. In this paper, we propose a new measurement of semanticcentrality, i.e., the power of semantic bridging on semantic peer-to-peer environment. Thereby, we want to build semantically cohesive user subgroups, so that semantic affinities between peerscan be computed. Then, given a query, we find out a path of peers for optimal interoperability between a source peer and a target one, i.e., minimizing information loss by the transformation.We have shown an example for retrieving image resources annotated on peer-to-peer environment by using query transformation based on semantic centrality.

semantic social network, ontology alignment, query propagation