SKOS with OWL: Don't be Full-ish!

The Simple Knowledge Organisation System (SKOS) is a vocabulary intended for the representation of Knowledge Organisation Systems (KOS) such as thesauri, term lists and controlled vocabularies. The SKOS data model is defined using an RDF schema so that it fits in with existing Semantic Web technologies. We speculate how SKOS artefacts may be used in combination with other knowledge artefacts, such as ontologies represented in the Web Ontology Language (OWL) . The SKOS schema is currently OWL-Full which has implications when using SKOS in combination with ontologies expressed in some decidable fragments of OWL, such as OWL-DL. We demonstrate that some of the issues can be addressed with the introduction of rich annotations and/or punning into OWL-DL, which could be beneficial to both the SKOS and OWL communities. Representing domain knowledge in the form of ontologies has become increasingly popular in recent years. The use of these technologies in the context of the web has been further boosted by the development of standards like the Resource Description Framework (RDF) and OWL. In addition to representing knowledge in the form of OWL ontologies, there also exist other knowledge artefacts where representation in OWL is deemed inappropriate. These KOS, which include things like thesauri, subject heading systems and taxonomies have been used in the library and information science domains for many years [4], [5], [3], mostly for the purpose of query expansion and document navigation. SKOS is being developed as part of W3C’s Semantic Web Deployment Working Group (SWDWG) activity, and Editors’ Working Drafts of the SKOS reference and SKOS Primer are now available. This paper includes some speculative ideas. Although precise motivations for the use cases we propose are still unclear, investigating potential patterns for the combination of SKOS and OWL-DL does help to highlight some issues. By doing this at an early stage, we can bring these issues to the attention of both the SKOS and OWL communities and ensure that decisions about the future of both standards do not rule out any potentially desirable use cases in the future. Our discussions highlight some potential conflicts between SKOS and OWL-DL and suggest how they could be achievable via some extensions to OWL-DL. By