Semantic integration is an active area of research in several
disciplines, such as databases, information-integration, and
ontologies. This paper provides a brief survey of the approaches
to semantic integration developed by researchers in
the ontology community. We focus on the approaches that
differentiate the ontology research from other related areas.
The goal of the paper is to provide a reader who may not
be very familiar with ontology research with introduction to
major themes in this research and with pointers to different
research projects. We discuss techniques for finding correspondences
between ontologies, declarative ways of representing
these correspondences, and use of these correspondences
in various semantic-integration tasks