lKAT: A TOOL FOR INCREMENTAL DEVELOPMENT OF ONTOLOGIES THROUGH VERSIONS Mikel Larrafiaga, Jon A. Elorriaga University olthe Basque Country Abstract: In this paper an ontology-based knowledge acquisition tool is presented. This work is focused on the incremental development of ontologies and aims to help with the creation and maintenance of knowledge-based systems. The tool uses the version concept to implement the evolution of the ontologies. IKAT facilitates the development of ontologies through versions propagating automatically changes to the knowledge bases built based on them. An analysis of the possible operations upon ontologies has been carried out, and as a result a set of plausible operations has been chosen and their treatment implemented. Key words: Knowledge acquisition, ontologies, knowledge engineering, reusability. 1. INTRODUCTION Ontologies, which had been used in other areas such as philosophy, were adopted to represent the knowledge in order to minimize the communication difficulties in KBS development teams. In knowledge engineering area, ontologies are defined as " an explicit specification of a conceptualization" [3]. They provide a formalism for the representation of a concrete domain that can be understood without any ambiguity either by different people or by a computer. Obviously, a broadly accepted representation of the domain is hardly reached immediately, so the process of building ontology must be gradual and requires several refinements. Many ontology-based tools appeared with the aim of relieving the mentioned bottleneck by minimizing the knowledge engineers role as they allow domain experts to transfer their knowledge to a computer system even though they are not familiar with computers. Some of these tools are Protege- M. A. Musen et al. (eds.), Intelligent Information Processing © International Federation for Information Processing 2002