- From: Bernard Vatant <bernard.vatant@mondeca.com>
- Date: Tue, 22 Jul 2003 13:14:43 +0200
- To: "WebOnt" <www-webont-wg@w3.org>
Find below the cc of a message I've sent today to the Protégé mailing list. Not to get answers on this forum, of course (although I would welcome any knowledgeable answer privately), but sending it, I was wondering if it is intended by WebOnt group to develop and somehow annex to OWL specification some informative document(s) about that kind of modeling issues, and/or guidelines or references to best practices, modeling in OWL-FAQ, whatever ... I know this is not explicitly in the charter nor deliverables. It might even be contradictory with the requirement "The products of the WebONT group should not presuppose any particular approach to either ontology design or ontology use." OTOH the specification have made a considerable, and I would say, unusual, effort of pedagogy. I figure this is about to trigger ontology development and maintenance to spread outside the original core community of AI and Knowlegde Engineers, and become mainstream technology. From what I see around, this trend is already there. Based on experience in helping customers in Topic Maps modeling - which implies mastering of a handful of not so hard to grasp concepts - I'm concerned with the perspective of a rapidly growing demand of modeling support from OWL potential users, and some good tutorial literature about it would be indeed very important to face this demand and help adopters to avoid syntactic hacking and really use OWL in a way that "makes sense". I would of course gladly volunteer to contribute to such an effort by any means that this group would find relevant. Bernard Bernard Vatant Senior Consultant Knowledge Engineering Mondeca - www.mondeca.com bernard.vatant@mondeca.com -----Message d'origine----- De : Bernard Vatant [mailto:bernard.vatant@mondeca.com] Envoyé : mardi 22 juillet 2003 12:24 À : protege-discussion@SMI.Stanford.EDU Cc : Jean Delahousse Objet : Modeling issue : Should subclassing always go along with property specification? This is a quite fundamental modeling issue that I have not yet seen explicitly addressed either in various litterature I have gathered on ontologies, no more than in Protégé guidelines. In short : Does it make sense to create a subclass without specifying some new property for it, or some specific restriction on properties of the superclass? The rationale of this question is that e.g. in biological taxonomy, the creation of a subclass is always, AFAIK, linked to specification of some characteristic(s), enabling with the less ambiguity possible, to distinguish an instance of the subclass from a generic instance of the superclass, and/on from other subclasses. This best practice I have learnt, as an occasional amateur bird-watcher. But, as a matter of fact, outside biological taxonomy, I've not came across so many ontologies where this rule is really enforced, and every subclass explicitly defined by specific set of properties or restrictions. "Lazy" ontology building is often in fact re-engineering of a Thesaurus, extracting implicit classes and class-subclass relationships hidden under generic-specific relationships, resulting in a rich class-subclass hierarchy without any properties underlying the subclassification - simply because they are not asserted in the Thesaurus source. Is it correct to consider that practice as underspecified modeling, and that such ontologies can only be used by human editors making somehow sense of the meaning of subclasses names and context - assuming they are more or less "domain experts". But in no way such ontologies can be used e.g. for automatic classification, since no system can make use of non-explicit properties. A contradictory argument, in favor of that kind of underspecified modeling is that enforcing such a constraint for large ontologies building and maintenance is a serious overhead, both from modeling cost and system scalability viewpoints. Any clues on ideas, practices on that issue, or references to literature where it has been addressed, are welcome. Thanks for your attention. Bernard Bernard Vatant Senior Consultant Knowledge Engineering Mondeca - www.mondeca.com bernard.vatant@mondeca.com
Received on Tuesday, 22 July 2003 07:14:50 UTC