Cluster Entries for Semantic Organization of Peer-to-Peer Network

Abstract

Techniques of pure flooding queries through a peer-to-peer network [1] reach their limits for data localization which are not replicated and stored through a high number of nodes. To improve implicitly the query routing towards relevant nodes in order to smartly recover all the relevant data, we propose to organize a peer-to-peer network in which the logical neighborhood of each node is built according to the semantic of its content. Indeed, the data we target, are semantically rich, easily classifiable with a field of interest, or a theme (e.g. "rock", "jazz", … in music, or "hydrology", "oceanography",… in sciences of environment). The motivation of our approach is based on the fact users/providers query the network on the theme of the data they store. Thus, if a node contains many data about the theme "Hydrology", the query propagation is more efficient, if the neighbors of this node contain data about "Hydrology". In the prototype VENISE (serVicE for Node Insertion in Semantic clustErs), we propose a protocol of node insertion based on cluster entries to cluster a peer-to-peer network. Semantic RepresentationsTo build a network organized according to the semantic content of nodes, we define -a set of theme statically established and used as common referential to semantically compare nodes. -the semantic representation of each node, named Thematic Vector. The values of this vector contain the proportion of data stored on the node according to each theme. -the semantic representation of each cluster, named Aggregation Vector. The values of this vector are learnt by a Machine Learning technique to take into account the aggregation of Thematic Vectors of nodes contained in the cluster and the semantic distance between clusters. Thus, a neural network is used as in the approach of self organizing maps[2] to classify nodes in cluster.* This research is done in the context of the PADOUE project

Thematic Schema Building for Mediation-based Peer-to-Peer Architecture

“…Some queries will be handled directly from mediator to mediator, other queries will be handled via peer-to-peer communication layer. As our solutions are based on an important interaction between nodes, we propose a protocol of network clustering [11,12] in order to logically gather (in terms of logical neighborhood) nodes which store data concerning the same themes. We will thus improve the management of interactions between nodes of a peer-to-peer network.…”