Ling Liu
Dept. of Computer Science and Engineering
Oregon Graduate Institute
P.O.Box 91000 Portland, Oregon
97291-1000 USA
email: lingliu@cse.ogi.edu
Calton
Pu
Dept. of Computer Science and Engineering
Oregon Graduate Institute
P.O.Box 91000 Portland, Oregon
97291-1000 USA
email: calton@cse.ogi.edu
We describe a rule-based approach to semantic specification that can be used to dynamically establish semantic relevance between consumers' queries posed on the fly and producers' data sources available online. The semantic specification of user queries is independent of the content and capabilities of the data sources (query-to-source independence). The semantic specification of the content and capability of a data source is independent of the content and capability descriptions of other sources (source-to-source independence). Query processing techniques use these specifications along with the query modification and transformation routines to perform relevance reasoning and to guarantee semantically correct query answers. This work also examines the effect of changing metadata semantics, such as changes in the content and capability descriptions of data sources or the user query profile specifications. Methods are described for detecting these changes and for determining if the information sources can continue to supply meaningful data to answering consumers' queries. These methods and transformation routines are necessary for determining logical connectivity between information producers and information consumers and for establishing dynamic interconnection between a growing collection of data sources and a consumer's query.