Query Reformulation for Distributed Information Gathering

With multiple heterogeneous information sources accessible in modern networked environments, users and applications cannot be expected to keep up with all their speciic languages, organizations, contents and network locations. Yet the need for the data available from these sources remains. Users and applications would beneet greatly from the ability to formulate queries in a language that is free from any reference to speciic information sources. SIMS is a system that supports such querying. This paper describes how SIMS can reformulate a high-level query that describes only the desired information into a query that makes explicit the information sources that need to be accessed and the data that needs to be retrieved from each. To perform this task SIMS uses models, declarative descriptions of the application domain and the available information sources, and reformulation operators that are used to successively rewrite portions of the query until all needed information sources are made explicit. This approach provides a exible and extensible system for integrating heterogeneous information sources. We have demonstrated the feasibility and eeectiveness of this approach by applying SIMS in the domains of transportation planning and medical trauma care.