Enrichment of OWL Ontologies: a method for defining axioms from labels

Abstract

An increasing interest has provoked the development of a significant number of ontologies, and many more are expected to be produced in the next years. A significant proportion of such ontologies have not been created by computer scientists or ontology engineers, but by domain experts. Many of such ontologies are rich in implicit knowledge, but are really basic taxonomies and controlled vocabularies, with little axiomatization. Many such ontologies have much information within the labels of the classes. There is a great deal of knowledge about the entities described within such labels and text definitions held on classes; these are useful for human users, but not for machine processing. In previous work we proposed a process for enriching ontologies which included the analysis of such labels, the identification of linguistic patterns and the design of knowledge patterns from them. However, such processes relied on manual intervention. In this paper we present a method and tool to guide the process of including axiomatisation in ontologies through the study of labels. This method guides domain experts in the definition of OWL axioms. The first step is the identification of linguistic patterns based on repetitions of sets of words. Second, the expert is provided with such patterns and recommendations about the existence of classes and properties in such labels by reusing existing ontologies. Third, the user is guided in the process of defining knowledge patterns that would code both the axioms to be added in the ontology and the classes that would be affected. Such axioms would also re-use existing ontologies. Such knowledge patterns are coded and executed using the Ontology Pre-Processor Language (OPPL), but our tool permits their definition without advanced knowledge of OPPL. Finally, we describe the application of the method and tool to the Molecular Function ontology of the Gene Ontology.