Ontology-based distributed autonomous knowledge systems

Traditional query processing usually requires that users fully understand the database structure and content to issue a query. Due to the complexity of the database applications and the variety of user needs, the so-called global queries are introduced which traditional query answering systems cannot handle. Query posed to a database D is global if minimum one of its attributes is missing in D while it occurs in other databases. Definitions of a missing attribute in D can be extracted from other databases and shared with D. To handle semantics inconsistencies between the same attributes used at different sites, task ontologies are used as a communication bridge between them. These inconsistencies can be caused either by different granularity levels or by different interpretations of the same attribute. As the final outcome of this research, a rough query answering system based on distributed data mining is presented.