- From: Florian Probst <f.probst@uni-muenster.de>
- Date: Wed, 04 Feb 2004 11:16:49 +0100
- To: Pat Hayes <phayes@ihmc.us>
- Cc: Bijan Parsia <bparsia@isr.umd.edu>, public-sws-ig@w3.org
Hi, I nearly don't dare to ask the question, but what use is an ontology if you can not proof its consistency and infer new information from it? Currently I don't see another option than using DL-based reasoners. What are the advantages of using OWL-full that will weight up consistency checking and classification? Cheers Florian Pat Hayes schrieb: > >> If OWL-S ontologies are to be OWL-DL, then we must eliminate all >> "extraneous" use of the RDF collection vocabulary. (That is, we must >> only use rdf:List and friends in certain syntactic situations and >> never as a user level modeling construct.) There are three places >> where we do or might use collections: >> >> 1) As the value of the components property, especially for indicating >> sequences or unordered sets of processes. Note that simply avoiding >> subclassing rdf:List isn't sufficient. The mere use of lists puts us >> in OWL Full. > > > Restrictions like this were SUCH a bad idea. Sigh. The torture that > you are now going through illustrates the reasons why. The entire > OWL-S process is going to be warped in order to save the tool builders > the trouble of having to do some intelligent parsing. > >> 2) It seems somewhat natural to describe certain parameters as >> consuming or returning lists of objects. >> >> 3) DRS may make use of lists in describing formulas. >> >> Disposing these in reverse order: >> >> 3) If DRSyly described preconditions and effect formulas are >> associated with a process by a datatype property whose values are >> XMLLiterals that contain the RDF/XML for the DRS formulas, then the >> parent KB will be in OWL DL even if the literals themselves are OWL >> Full. I think it would be better if it were DL all the way down, but >> hey. It's a compromise :) >> >> 2) Don't Do That. >> >> 1) Don't Do That. >> >> Ok, but what can we do instead of 1 or 2. Some choices: >> >> a) Define a shadow collection vocabulary, e.g., owls:List and >> friends. Use as one does the RDF collection vocabulary. If one wants >> compatibility with OWL Full tools, one can define an ontology which >> contains the requisite equivalences and simply import it when dealing >> with OWL Full tools. Conversely, it wouldn't be hard to write a >> lint-esque tool that too OWL Full kbs with modest use of the >> collection vocabulary that replaces those uses with the corresponding >> items from the shadow vocabulary. The big loss is that in OWL-DL >> compatible kbs, you couldn't use the parseType="Collection" short cut >> (note, you already can't do this for lists of datavalues). Well, boo >> hoo. We could publish an XSLT sheet that took care of this. >> >> b) Use alternative modeling altogether. For example, for sequences, >> we can have a sequence object where each owls:item had a >> distinguishing property value that allowed us to recover the order. >> It could be a "line number", or a "tag" (as in the surface syntax), >> or what have you. There'd be some tedium in representing the fixed >> total number of items and the distinctness of the items, but nothing >> too bad. >> >> c) Do something exceedingly clever with literals. Literals already >> *have* structure (both xml and the simpleType, list). >> >> Any thoughts, preferences, screams of pain anyone would like to share? > > > Thought: Serves you right for trying to fit into OWL-DL > > Preference: use option (a). There is almost no semantics associated > with rdf:List etc. that couldnt be associated with owl:List or even > fred:List. To hell with parseType, its a crock anyway. Option (b) is > more work for no perceptible advantage, and option (c) is a Really Bad > Idea. Really Really Bad. > > Screams of pain: I would be emitting them if I thought that I had to > use OWL-DL. > > Pat > >> Cheers, >> Bijan Parsia. > > > -- Florian Probst Institute for Geoinformatics (ifgi) Robert-Koch-Str. 26-28 D - 48149 Muenster fon_________+251 83-30058 fax_________+251 83-39763 mail________f.probst@uni-muenster.de ifgi________http://ifgi.uni-muenster.de personal____http://ifgi.uni-muenster.de/~probsfl
Received on Wednesday, 4 February 2004 05:17:22 UTC