ABSTRACT
In this chapter, we introduce the ontology language OWL. We focus on an introduction to the syntax and on conveying an intuitive understanding of the semantics. We will also discuss the forthcoming OWL 2 standard. A formal treatment of the semantics will be done later in Chapter 5, and a discussion of OWL software tools can be found in Section 8.5. We have seen at the end of Chapter 3 that RDF(S) is suitable for modeling
simple ontologies and allows the derivation of implicit knowledge. But we have also seen that RDF(S) provides only very limited expressive means and that it is not possible to represent more complex knowledge. For example, it is not possible to model the meaning of the sentences from Fig. 4.1 in RDF(S) in a sufficiently precise way. For modeling such complex knowledge, expressive representation languages
based on formal logic are commonly used. This also allows us to do logical reasoning on the knowledge, and thereby enables the access to knowledge which is only implicitly modeled. OWL is such a language. The acronym OWL stands for Web Ontology Language.1 Since 2004 OWL
is a W3C recommended standard for the modeling of ontologies, and since then has seen a steeply rising increase in popularity in many application domains. Central for the design of OWL was to find a reasonable balance between expressivity of the language on the one hand, and efficient reasoning, i.e. scalability, on the other hand. This was in order to deal with the general observation that complex language constructs for representing implicit knowledge usually yield high computational complexities or even undecidability of
Every project has at least one participant. Projects are always internal or external projects. Gisela Schillinger and Anne Eberhardt are the secretaries of Rudi Studer. The superior of my superior is also my superior.
