Ontologias

Part 3: Advanced course of ontological engineering Author: Riichiro Mizoguchi Abstract This article deals with advanced topics of ontological engineering to convince readers ontology is more than a rule base of terminological problems and is worth to consider a promising methodology in the next generation knowledge processing research. Needless to say, ontology in AI is tightly connected toontology in philosophy. The first topic here is on philosophical issues which are very important to properly understand what an ontology is. After defining class, instance and is-a relation, we point out some typical inappropriate uses of is-a relation in existing ontologies and analyze the reasons why. Other topics are basic ontological distinction, part-of relation, and so on. As an advanced exampleof ontology, an ontology of representation is extensively discussed. To conclude this tutorial, a success story of ontological engineering is presented. It is concerned with a new kind of application of ontology, that is, knowledge systematization. An ontology-based framework for functional knowledge sharing has been deployed into a company for two years and has been a great success. Finally,future of ontological engineering is discussed followed by concluding remarks. 1. Fundamental issues 1.1 Background 1.2 Class and is-a relation 1.2.1 Inappropriate use of is-a link 1.2.2 The causes of such misuse of is-a relation 1.2.3 OntoClean 1.3 Ontological distinction 1.4 Concept of a role 1.5 Instance vs. occurrence 1.6 Kinds of a part-of relation 1.7 Data, information and knowledge 2. Ontologyof Representation 2.1 Two principles 2.2 A conceptual model of representation 2.3 An ontology of representation 3. Guidelines of ontology building 4. A success story of ontology research 4.1 Systematization of functional knowledge 4.2 Deployment into the production division of an industry 5. Future of ontological engineering 6. Concluding remarks

1. Fundamental issues Building an ontology needsa lot of skill and knowledge about fundamental issues. This section discusses issues which have to be seriously investigated to build a good ontology. 1.1 Background One of the most critical contributions of an ontology is that it gives the higher level distinction of concepts which help understand the lower level concepts, that is, domain concepts systematically and consistently which is hard toattain without ontological ways of thinking. The main topic here is so-called ontological distinction which is indispensable for designing upper ontology. An ontology

design is a kind of design activity which necessarily has some design rationale that largely influences the resulting ontology. In other words, any ontology cannot be free from some assumption and/or designer’s standpoint. Thestandpoint taken in this article consists of Newtonian world point of view and 3D modeling, that is, the world is considered as being composed of the three-dimensional Euclidean space with the absolute time and both object(continuant) and process (occurrent) exist with equal importance. The latter is discussed in detail below. One of the difficulties in understanding ontology research is thedefinition of each concept. How deeply and rigorously should we define a concept? How is an ontology different from a dictionary in word definition? These are common questions about this topic. A dictionary consists of definitions of terms people use for human consumption and basically tries to cover as many terms as possible. Some says an ontology is a computer-understandable dictionary. Although it isnot incorrect, it tends to lead people to a misunderstanding about ontology. It is critical to note that in principle, it is impossible for us to define the meaning of each term/concept in a computer as we understand it. Try to define what a human is as you understand it. A human is living. What is “living”? He/she falls in love, laughs, cries, eats, produces an artifact, walks, dies, etc. How...