User defined ontology change and its optimization

Ontology evolution is a familiar problem in ontology application. How to describe change requirement of the user is one of key elements in ontology evolution. Aiming at the problem that ontology change types canpsilat be presented exhaustedly, user defined ontology change is put forward to improve flexibility of change description in the paper. Ontology consistency restriction is given to assure the consistency of ontology. Atomic changes of ontology and the relation of ontology atomic change are described. Definition methods of user defined change are presented. User defined change includes multiple atomic changes which is called ontology atomic change sequence. There is redundancy usually in ontology atomic change sequence. The redundancy can be eliminated through optimization to shorten executing time of user defined change. Two optimization operations, eliminate operation and cancel operation are adopted in the paper. Experiments show that optimization method in the paper can reduce redundancy of user defined change.