Abstract

Ontology is generally not static. From time to time, it needs expansion to include new concepts, properties, and relationships. One way to expand ontology O1 is by adding with a sub-ontology extracted from existing ontology O2. Obviously this method covers two major aspects, particularly extracting a sub-ontology from O2, and adding the extracted sub-ontology to O1. In the first phase, we will introduce two extraction methods, namely Maximum and Minimum Extraction methods. And then in the second phase, these two extraction methods will be applied to the proposed ontology expansion process. UMLS meta-thesaurus ontology is used as a case study to illustrate our proposed methods