Variable−Strength Conditional Preferences for Ranking Objects in Ontologies

Abstract

We introduce conditional preference bases as a means for ranking objects in ontologies. Conditional preference bases consist of a description logic knowledge base and a finite set of variable-strength conditional preferences. They are inspired by Goldszmidt and Pearl's approach to default reasoning from conditional knowledge bases in System Z+. We define a notion of consistency for conditional preference bases, and show how consistent conditional preference bases can be used for ranking objects in ontologies. We also provide algorithms for computing the rankings. To give evidence of the usefulness of this approach in practice, we describe an application in the area of literature search.