- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Mon, 26 Nov 2007 08:59:46 -0500 (EST)
- To: bparsia@cs.man.ac.uk
- Cc: public-owl-wg@w3.org
From: Bijan Parsia <bparsia@cs.man.ac.uk> Subject: Re: Rich Annotations Date: Mon, 26 Nov 2007 13:32:27 +0000 > On 26 Nov 2007, at 11:19, Peter F. Patel-Schneider wrote: > > > From: Bijan Parsia <bparsia@cs.man.ac.uk> > > Subject: Re: Rich Annotations > > Date: Mon, 26 Nov 2007 10:24:53 +0000 > > > >> On 26 Nov 2007, at 09:13, Peter F. Patel-Schneider wrote: > >> > >>> > >>> From: Bijan Parsia <bparsia@cs.man.ac.uk> > >>> Subject: Re: Rich Annotations > >>> Date: Sun, 25 Nov 2007 15:40:06 +0000 [...] > >>>> It isn't magic, just a hook. This is no different than the current > >>>> situation *except* I have a way of indicating to arbitrary tools > >>>> that > >>>> I've included an extension. That's all this is doing. > >>> > >>> Yes, this may be *all*, but it seems to me to be a very big all. > >> > >> Yeah, and I have no idea why. > > > > Because it pushes parts of the OWL specification into other places. > > No. It pushes specification of *extensions* to OWL to other places. > Which is already the case and would be, I imagine, true of *any* > extensibility mechanism. Before you were arguing against some details > of *this* proposal (and in favor of a somewhat different > extensibility mechanism). Now you seem to be arguing against > extensibility at all (at least extensibility used by people outside > the W3C). I have no problem with others creating extensions to OWL, as long as the extension doesn't mess OWL itself and the extension can be recognized. However, yes, indeed, I am arguing against the OWL spec providing hooks for extensions, particularly ones that change the meaning of OWL constructs. I do realize that many extensions don't meet the second requirement above. I view this as deplorable, but I don't see the proposal as providing a good way to ameliorate the problem. > [snip] > > >> After all, there *are* > >> pointers in: > >> http://www.w3.org/2007/OWL/wiki/Annotation_System#Examples > > > > What I see there are three examples of extensions to OWL. For > > constraints and OntoClean, I don't see a worked-out solution as to how > > the annotation proposal would support the extension. For Pronto, I > > see > > annotations, but no annotation spaces. > > Because when we did Pronto, the proposal wasn't on the table. > > Really, is it that hard to see how it would go? See below. Yes, for me it is hard to see how it would go. I couldn't (easily) find a manual for Pronto. I looked at Probabilistic Description Logics for the Semantic Web by Thomas Lukasiewicz, and quickly ran into problems, starting with how to write arbitrary real numbers in OWL. I also didn't see a close correspondence between the language there and the example Pronto ontology at http://www.ece.uc.edu/~klinovp/pronto/cancer/cancer_ra.owl. [...] > >> Perhaps you could work through how one of them would work and I could > >> check to see if our understandings aligned. > > > > No thanks. > > Why not? I'm really at a loss as to which parts are puzzling you. > Wouldn't it be a better test of the design if you tried it? > > > How about you work through how one of them would work and I could > > see if > > I can understand more? > > Here's a sketch. > > Ontology(<http://ex.org/#testOnt> > AnnotationSpace(<http://ex.org/Pronto> mustUnderstand) > SubClassOf( Annotation(<http://ex.org/Pronto> <http://ex.org/ > Pronto#certainty> 0;0.132) Woman, WomanWithBRCInLongTerm) > ) What is the role of the annotation property <http://ex.org/Pronto>? What is the role of the annotation value <http://ex.org/Pronto#certainty>? What is the role of 0;0.132? How do they connect to the Pronto extension to OWL? Are there syntactic restrictions on the annotations? > There is a bit of ambiguity in the space uri (i.e., does it identify > the particular space token or the space type), but that's easily > decided one way or the other. > > If a reasoner gets this and it doesn't have this space in its > internal list of understood annotations then it should punt on the > file ("Can't reason with this file because I don't understand <http:// > ex.org/Pronto> annotations; The annotation space or the annotation property? > I could reason with this file while > ignoring those annotations but the results may not be as the ontology > author intended.") > > In order to (correctly) reason with documents with these annotations, > the tool must conform to the relevant spec. I do not propose that > such specs be necessarily accessible via the annotation space URI or > anything like that (though one could do and I imagine many people > will). I just publish my spec. Usually a googling will suffice to > find it. You mean the document at http://www.pronto.philips.com/, which is the current first Google hit for Pronto? > This is very much how SWRL, for example, currently works except there > is no hint to vanilla OWL reasoners that SWRL rules encoded as RDF > statements have significant extra-OWL/RDF semantics. In fact, there > is no *way* to so hint. Oh, I very much agree that the encoding of SWRL rules as RDF triples is a bad idea. > This is a way to so hint. It doesn't stop > someone from claiming that their ad hoc rule engine (or dl safe rule > engine) correctly implements the SWRL spec. But so? It gives a > standard way for an OWL tool to tell the user that it is, for all > that it knows, not respecting the semantics of the extension. If the > author doesn't put in the mustUnderstand, then, too, the mechanism > won't work. My view is that the way ahead is to have a real rule extension to OWL (probably not SWRL), with its own syntactic constructs, as is done in the SWRL abstract syntax. Proposals that provide band-aids for broken solutions are not advances, in my view. > Cheers, > Bijan. Peter F. Patel-Schneider Bell Labs Research
Received on Monday, 26 November 2007 14:18:18 UTC