tOWL: Integrating Time in OWL

The Web Ontology Language (OWL) is the most expressive standard language for modeling ontologies on the Semantic Web. In this chapter, we present the temporal OWL (tOWL) language: a temporal extension of the OWL DL language. tOWL is based on three layers added on top of OWL DL. The first layer is the Concrete Domains layer, which allows the representation of restrictions using concrete domain binary predicates. The second layer is the Time Representation layer, which adds time points, intervals, and Allen’s 13 interval relations. The third layer is the Change Representation layer which supports a perdurantist view on the world, and allows the representation of complex temporal axioms, such as state transitions. A Leveraged Buyout process is used to exemplify the different tOWL constructs and show the tOWL applicability in a business context.