A Review of Ontology and Web Service Composition

The term ontology is originated from Philosophy and was adopted by AI researchers to describe formal domain knowledge. Several ontology definitions have been proposed in the last decades. The most frequently cited definition is that given by Gruber in 1993, that is, ontology is defined as “an explicit specification of a conceptualization”. In other words, an ontology is a domain model (conceptualization) which is explicitly described (specified). Borst defines ontology as a “formal specification of a shared conceptualization” later [Borst, 1997]. This definition requires, in addition to Gruber’s definition, that the conceptualization should express a shared view between several parties, a consensus rather than an individual view. Also, this conceptualization should be expressed in a machine readable format. In 1998, Studer et al. [Studer et al., 1998] merge these two definitions as “An ontology is a formal, explicit specification of a shared conceptualization.”