Distributed Instance Retrieval in Heterogeneous Ontologies

The problem of ontology querying is of a crucial importance for a practically usable semantic web. Recent research in standard Description Logics has produced a number of algorithms and implementations for reasoning with instances for answering ontological queries. In this work, we extend these techniques to enable a querying of distributed heterogeneous ontologies with heterogeneous populations. We follow a peer-to-peer paradigm that of combining local ontology query answering with answering over other semantically related ontologies. Our approach is formally grounded on Distributed Description Logics (DDLs) and limited to the instance retrieval queries. The contribution of the paper is twofold. From the theoretical perspective we extend the semantics of DDLs with instances which allows to define an instance retrieval algorithm. From the practical hand, we describe how the proposed algorithm can be implemented on top of DRAGO distributed reasoner.