"In Semantic Web languages, such as RDF and OWL, a property is a binary relation: it is used to link two individuals or an individual and a value. However, in some cases, the natural and convenient way to represent certain concepts is to use relations to link an individual to more than just one individual or value. These relations are called n-ary relations. For example, we may want to represent properties of a relation, such as our certainty about it, severity or strength of a relation, relevance of a relation, and so on. Another example is representing relations among multiple individuals, such as a buyer, a seller, and an object that was bought when describing a purchase of a book. This document presents ontology patterns for representing n-ary relations in RDF and OWL and discusses what users must consider when choosing these patterns."
The NCI Thesaurus is an ontology-like vocabulary that includes broad coverage of the cancer domain, including cancer related diseases, findings and abnormalities; anatomy; agents, drugs and chemicals; genes and gene products and so on.
The Buffalo Ontology Site is maintained by Barry Smith. It contains information on ontology, on the history of ontology, and on contemporary ontology and its applications, with special reference to the area of biomedicine. It provides links to other ontology sites and announcements of relevant conferences and publications.
Knoodl is sort of an ontology editor, registry/repository, and wiki all rolled into an easy to use online application. There's never been anything quite like it.
* Upload an ontology you already have, or build one from scratch.
* Add rich documentation with wikitext, so that other people can understand what your ontology is about.
* Work with other people on the same vocabulary, at the same time
* Find and download other ontologies and use them in semantic applications.
C. Joslyn. Proceedings of the 12th International Conference on Conceptual Structures (ICCS 2004), Volume 3127 von Lecture Notes in Computer Science, Seite 287-302. Springer, (2004)
P. Martin, M. Blumenstein, und P. Deer. Proceedings of the 13th International Conference on Conceptual Structures (ICCS 2005), Volume 3596 von Lecture Notes in Computer Science, Seite 411-424. Springer, (2005)