Introduction to Ontologies

An ontology necessarily entails or embodies some sort of world view with respect to a given domain. The world view is often conceived as a set of concepts (e.g. entities, attributes, and processes), their definitions and inter-relationships; this is referred to as a conceptualisation.

The primary goal in creating ontologies is to provide a common data representation framework to facilitate the integration of multiple sources to draw new conclusions. In other words, to achieve information integration at a Web scale.

The motivation behind the development of ontologies in AIM@SHAPE falls in the following areas:

• Sharing a common understanding of the information in some target knowledge domains within the area of Computer Graphics
• Improving interoperability among applications that use the domain knowledge
• Making domain assumptions explicit so that applying changes as these assumptions evolve becomes easier
• Enabling re-use of the domain knowledge

Probably the most important aspect of ontology development involves the choice of the formal representation language to describe the ontology. The choice of language reflects mainly on the expressive power that will be available and its relation to other logical representation constructs. Transforming the ontology specification to other equivalent representations (i.e. description logic) can have the advantage of exploiting tools for deductive reasoning that may already be available in the target representation language. Reasoners can help in discovering implicit knowledge, but also in the validation and consistency checking of the entire knowledge base.

The ontology language that is being used in the AIM@SHAPE network is OWL, while an extension to support SWRL rules is also under development. RacerPro is utilized to provide reasoning on the knowledge base.