A framework for spatiotemporal reasoning has to account for the variety of modes of existence and persistence in time. It should thus be based on a formal ontology of spatiotemporal reality. For pragmatic reasons, however, it is even better if while being based on a realist foundation, the framework has the potential of being extended and amended contextually. I propose a rich modular framework based on a realist formal ontology of spatio-temporality. I present the ontology as a theory and position it with respect to the variety of spatiotemporal theories. The theory defended has the privilege and strength of being realist, and generates a framework having the potentiality to cope modularly with more exotic theories.
Despite its original intended use, which was very different, WORDNET is used more and more today as an ontology, where the hyponym relation between word senses is interpreted as a subsumption relation between concepts. In this article, we discuss the general problems related to the semantic interpretation of WORDNET taxonomy in light of rigorous ontological principles inspired by the philosophical tradition. Then we introduce the DOLCE upper-level ontology, which is inspired by such principles but with a clear orientation toward language and cognition. We report the results of an experimental effort to align WORDNET's upper level with DOLCE. We suggest that such alignment could lead to an "ontologically sweetened" WORDNET, meant to be conceptually more rigorous, cognitively transparent, and efficiently exploitable in several applications.
Example from the LOOM WORDNet Knowledge Base. At the beginning, we assumed that the hyponymy relation could simply be mapped onto the subsumption relation and that the synset notion could be mapped into the notion of concept. Both subsumption and concept have the usual description logic semantics (Woods and Schmolze 1992). LOOM WORDNET knowledge base are reported in table 1. Fig-ORDNET's noun top Under Territorial_-Dominion, we find Macao and Palestine together with Trust_Territory. The Trust_Territory synset, defined as "a dependent country, administered by a country under the supervision of United Nations," denotes a general kind of country rather than a specific country such as Macao or Palestine.
Clarity in semantics and a rich formalization of this semantics are important requirements for ontologies designed to be deployed in large-scale, open, distributed systems such as the envisioned Semantic Web. This is especially true for the description of web services, which should enable complex tasks involving multiple agents. As one of the first initiatives of the Semantic Web community for describing web services, OWLS attracts a lot of interest and increases its user base even though it is still under development. Our contribution to the development of this ontology is to identify some of its problematic aspects and to suggest enhancements through alignment to a foundational ontology. However, the contribution of our work is not limited to the concrete results reported in this paper, but rather consists of examples of the benefits of alignment to foundational ontologies and a description of the method itself.