Ontologies -- What, Why and How

In philosophy, an ontology is the branch of metaphysics that deals with the nature of being. An ontology is a theory of what exists and lets us experience and operate in the world by, as Plato put it, "carving nature at its joints". In information systems, an ontology is an explicit formal specification of how to represent the objects, concepts and other entities relevant to some domain and the relationships that hold among them. An ontology provides a conceptualization of information to be represented in the computer and a vocabulary of terms to use in this representation.

This tutorial will cover the basics of how ontologies are being used in information system today. It will include a discussion of their history, the relationship to the semantic web, the languages and tools used for building and using ontologies, examples of large and small ontologies, some example applications that use ontologies, and speculations on how the ideas and technologies will develop.