The Constraint-Based Knowledge Broker system

Summary form only given. The amount of information available from electronic sources on the World Wide Web and other on-line information repositories is highly heterogeneous and increasing dramatically. Tools are needed to extract relevant information from these repositories. The Constraint-Based Knowledge Brokers project (CBKB) at RXRC Grenoble realizes sophisticated facilities for efficient information retrieval, schema integration, and knowledge fusion. The current implementation of the CBKB research prototype involves three kinds of agents: a) users, who input queries and process answers (i.e., ranking, fusion) through a GUI; b) wrappers, capable of interrogating heterogeneous information sources, which can provide answers to elementary queries (essentially various public bibliographic catalogues available on the Web, as well as preprint archives and opera information repositories); c) brokers, which can manage complex queries (i.e., decompose a complex query, recompose the partial answers, synthesize a full answer) and which mediate between the GUI and the different wrappers. The core of the system is given by the brokers, which provide various important services such as intelligent caching, filtering and knowledge combination. Requests, intermediate information, and results are internally represented via feature constraints. Requests do not need to be fully defined; they may correspond to partial specifications of the requested information