The amount of information available from electronic sources on the World Wide Web or other on-line information repositiories is increasing exponentially.
Tools are needed to extract relevant information from these repositories. The Constraint Based Knowledge Brokers project (CBKB) at XRCE Grenoble aims at developing sophisticated facilities for efficient information retrieval and combination.
In the CBKB model information requests are processed as follows:
Requests, information and results are represented via feature constraints. Requests do not need to be fully defined; they may correspond to partial specifications of the requested information. Furthermore, requests that cannot be fully satisfied may still obtain results in the form of partial objects that refine the initial requests by instantiating some of its attributes or by adding new attributes, thus providing user feedback.
A sophisticated engine for developing and executing Broker Agents has been implemented. This engine uses constraints to handle partially specified requests and supports reusability of results through powerful caching facilities. The Demand Agents are programmed as standard database query interfaces. The Supply Agents correspond to wrappers to WWW search engines and are mediated through normal RPC stubs.