Semantic Integration and Query of Heterogeneous Information Sources

Developing intelligent tools for the integration of information extracted from multiple heterogeneous sources is a challenging issue to e ectively exploit the numerous sources available on-line in global information systems. In this paper, we propose intelligent, tool-supported techniques to information extraction and integration from both structured and semistructured data sources. An object-oriented language, with an underlying Description Logics, called ODLI3 , derived from the standard ODMG is introduced for information extraction. ODLI3 descriptions of the source schemas are exploited rst to set a shared vocabulary for the sources. Information integration is then performed in a semi-automatic way, by exploiting ODLI3 descriptions of source schemas with a combination of Description Logics and clustering techniques and gives rise to a virtual integrated view of multiple sources. As the ultimate goal of providing an integrated view is querying the view, independently from the location/heterogeneity of the sources, a module for the reformulation of queries at the sources with semantic optimization capabilities is provided. Integration techniques described in the paper have been implemented in the MOMIS system, based on a conventional mediator architecture. This research has been partially funded by the italian MURST ex-40% INTERDATA project Metodologie e Tecnologie per la Gestione di Dati e Processi su Reti Internet e Intranet. A preliminary version of the paper appears in the proceedings of IJCAI-99 Workshop on Intelligent Information Integration 31 July 1999, Stockholm.