When the representation of the subject domain in an ontology requires features not available in OWL, the default response is typically ‘tough luck’. This is not exactly true. Common Logic (CL) and the Distributed Ontology, model and specification Language (DOL) were mentioned as an alternative way out in Section 4.3: OWL in Context "The Distributed Ontology, Model, and Specification Language DOL". It is not immediately clear, however, how exactly CL and DOL can assist with, say, probabilistic or temporal information. Also, for some ‘minor’ addition, one perhaps may not want to immediately leave behind all the Semantic Web tooling infrastructure. To some extent, such requirements have been met for especially uncertainty and vagueness, and extensions to OWL do exist, as we shall see. Temporal extensions have shown to be somewhat difficult, or: if one wants to remain within a decidable fragment of FOL, then there is not much temporal knowledge one would be able to represent. We will look at each in turn.
The main aim of this chapter is to provide several pointers to more advanced language features that allow the modeller to represent more than can be done with the DL-based OWL species only. We shall see some solutions to earlier-mentioned modelling question, among others: with which extension that “small” of the ‘small bladed hunting spear’ can be represented and how the essential and immutable behaviour of the parthood relation with the boxer and his hands vs. brain and human is resolved.
- 11.1: Uncertainty and Vagueness
- This advanced ontology engineering topic concerns how to cope with uncertainty and vagueness in ontology languages and their reasoners and what we can gain from all the extra effort. At the time of writing, this elective topic is mainly focused on theory and research, and a few proof-of-concept tools exist.