Temporal Traceability in Ontology Evolution Management

Abstract

Knowledge constantly grows in scientific discourse and is revised over time by different people. The body of knowledge will get structured and refined as the Communities of Practice concerned with a field of knowledge develop a deeper understanding of issues. The knowledge model, as a result, moves from loosely clustered terminology to semiformal or even formal ontology. Ontology change management is a complicated and multifaceted task, which has led to the emergence of several different, but closely related, research areas. Ontology Integration, Merging, Versioning, and Evolution, deal with different aspects of this problem. Different techniques have been introduced in literature that help in change management and query reformulation. Work on ontology recovery, and visualization of change effects on ontology is still a challenge to be solved for the purpose of keeping ontology consistent, and understanding the semantics of changes and evolution behavior of the ontology. To handle the above stated issues, we have developed a semantically rich and formally sound structure i.e. Change History Ontology (CHO) for logging all the ontology changes during evolution. On top of this we have proposed a comprehensive methodological framework for Change History Management. The ontology changes are captured and then stored in Change History Log (CHL) in conformance to CHO. The CHL is later used for reverting ontology to a previous consistent state and visualization of change effects on ontology during its evolution. We have developed and implemented algorithms which use CHL entries for visualization of change effects and reverting ontology to previous/next consistent states. A prototype system has been designed and implemented as a plug-in for Protégé ontology editor to verify and validate the proposed framework. First of all we have compared change detection accuracy of our system with Changes Tab of Protégé. Secondly, to verify and validate the correctness of roll-forward and roll-back algorithms, a comprehensive evaluation of the accuracy of roll-back and roll-forward algorithms have been conducted. For this, we have used three different versions of SWETO ontology along with the changes in all the versions. The changes are implemented in reverse and forward manners and the resulting ontologies are compared with their initial and final versions for the respective operations. Our system has outperformed Changes Tab of Protégé for capturing ontology changes. Accuracy of high percentage for roll-back and roll-forward algorithms is observed.