Ed
Ed Shaya a écrit :
> Bernard,
> Well, I have to agree to the point that OWL and SKOS have
> different aims. The aim of OWL is nothing less than expressing
> knowledge in computer readable form. SKOS is aimed at relating
> vocabulary terms, which one has to admit is a subset of knowledge.
> Therefore, you can easily incorporate the skos terms into an OWL
> ontology if you like. I provide an OWL skos ontology below.
> So now you can have within OWL skos:related, broader, narrower, and
> the various types of notes (description, historyNote, etc...), Concept
> and subjectOf property. And keep rigorous rdf:subClass. And make use
> of all of the OWL tools and utilities. In fact most of these
> "concepts" (including Concept) were already in our ontology
> http://archive.astro.umd.edu/ont/index.html at the top level,
> Science.owl), but I am happy to hand these over to the skos namespace
> as they are not really science terms.
Yes, of course. Including SKOS vocabularies in OWL classes is a
straightforward task. Just import a SKOS vocabulary in SWOOP and it
makes it for you :-)
>
> One should be careful though to use subClassOf if the thing is really
> a subClass and narrower if it is not a subClassOf but a related term
> within the scope of the broader term.
Beware that this kind of recommandation could be misleading. Be careful
to represent something as a skos:Concept if you want to use it this way,
and as a owl:Class if you need a cllass (I won't repeat myself too much
...). Then use consistent realtionships, subclassOf for classes, and
BT-NT for concepts.
> As for the specific example of white dwarf and Chandrasekhar limit
> (CL). In OWL you can restrict the WhiteDwarf to have Mass hasValue
> (maxValue hasValue CL). The CL is an instance of MassLimit.
> MassLimit are a subClassOf Mass. Measurements have property sci:of,
> which allows restriction: "CL of WhiteDwarf".
Maybe this works. I would like to see the formal OWL code, though (please reply privately, I don't think the list needs to see that gory things). Having Mass as a class with individual instances sounds weird ... OK. I don't want to go into a detailed modeling discussion, but I'm afraid that before you achieve widespread understanding, let alone consensus, on such representation for all possible astronomical concepts, you'll be a very old man, and will have pile up such complex a model that no one will ever dare use it in real life. :-)
> The question then is, do you bother to mention that CL and WhiteDwarf
> are also SKOS:related?
Because I will not index my docs/data with an instance of the "Mass"
class! I will index with a simple Thesaurus concept, simply "related to"
the white dwarf concept, without needing a reasoner to figure this
relationship out of a convoluted restriction of the maximal value of
some property on some class!
I will need other, simpler representations of the same "natural" concepts.
-- *Bernard Vatant *Knowledge Engineering ---------------------------------------------------- *Mondeca** *3, cité Nollez 75018 Paris France Web: www.mondeca.com <http://www.mondeca.com> ---------------------------------------------------- Tel: +33 (0) 871 488 459 Mail: bernard.vatant-at-mondeca.com <mailto:bernard.vatant-at-mondeca.com> Blog: Leçons de Choses <http://mondeca.wordpress.com/>Received on 2007-09-24Z18:35:11