Encapsulation and Composition of Ontologies
J. Jannink, S. Pichai, D. Verheijen, Gio C. M. Wiederhold · 1998
Ontology concerns itself with the representation of the objects in the universe and the web of their various connections. The traditional task of ontol-ogists has been to extract from this tangle a single ordered structure, in the form of a tree or lattice. This structure consists of the terms that represent the objects, and the relationships that represent connections between objects. Recent work in on-tology goes so far as to consider several distinct, superimposed structures, which each represent a classification of the universe according to a partic-ular criterion. Our purpose is to defer the task of globally clas-sifying terms and relationships. Instead, we focus on composing them for use as we need them. We define contexts to be our unit of encapsulation for ontologies, and use a rule-based algebra to com-pose novel ontological structures within them. We separate context from concept, the unit of onto-logical abstraction. Also, we distinguish compo-sition from subsumption, or containment, the re-lationships which commonly provide structure to ontologies. Adding a formal notion of encapsula-tion and composition to ontologies leads to more dynamic and maintainable structures, and, we be-lieve, greater computational efficiency for knowl-edge bases.