Expressive Description Logics for Agent-Based Information Retrieval

In this contribution we investigate the use of description logics (DLs) for information retrieval in a multiagent scenario. We first describe two advanced DLs and present the relevant reasoning services provided for information retrieval, in particular instance retrieval, instance checking and example-based instance retrieval. Complete and sound algorithms exist for each of these tasks in both DLs, but it is shown that a combined DL is undecidable. In order to make use of knowledge bases which use different DLs, a broker-based multiagent information retrieval scheme is presented. The main idea is to pose transformed queries to individual agents and combine the answers to obtain a correct but not necessarily complete result. The approach is illustrated with detailed examples.