Semantic integration of heterogeneous information sources

Developing intelligent tools for the integration of information extracted from multiple heterogeneous sources is a challenging issue to effectively 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 Logic, called ODL I(3), derived from the standard ODMG is introduced for information extraction. ODL I(3) descriptions of the source schemas are exploited first to set a Common Thesaurus for the sources. Information integration is then performed in a semiautomatic way by exploiting the knowledge in the Common Thesaurus and ODL I(3) descriptions of source schemas with a combination of clustering techniques and Description Logics. This integration process gives rise to a virtual integrated view of the underlying sources for which mapping rules and integrity constraints are specified to handle heterogeneity. Integration techniques described in the paper are provided in the framework of the MOMIS system based on a conventional wrapper/mediator architecture.