Abstract

It has long been realized that the web could benefit from having its content understandable and available in a machine processable form. The Semantic Web aims to achieve this via annotations that use terms defined in ontologies to give well defined meaning to web accessible information and services. OWL, the ontology language recommended by the W3C for this purpose, was heavily influenced by Description Logic research. In this chapter we review briefly some early efforts that combine Description Logics and the web, including predecessors of OWL such as OIL and DAML+OIL. We then go on to describe OWL in some detail, including the various influences on its design, its relationship with RDFS, its syntax and semantics, and a range of tools and applications.

Background and history

The World Wide Web, while wildly successful in growth, may be viewed as being limited by its reliance on languages such as HTML that are focused on presentation (i.e., text formatting) rather than content. Languages such as XML do add some support for capturing the meaning of web content (instead of simply how to render it in a browser), but more is needed in order to support intelligent applications that can better exploit the ever increasing range of information and services accessible via the web. Such applications are urgently needed in order to avoid overwhelming users with the sheer volume of information becoming available.