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Re: Comments on structural specification (was Re: document pubication schedule)

From: Boris Motik <boris.motik@comlab.ox.ac.uk>
Date: Wed, 24 Oct 2007 16:46:23 +0100
To: <public-owl-wg@w3.org>
Message-ID: <000301c81655$07aa9470$2711a8c0@wolf>


I would just like to stress that we (i.e., the creators of the OWL 1.1 proposal) did not use UML with the purpose of making some
strong statement about relationship between OWL 1.1 and other standards such as ODM. In fact, you should understand the diagrams as
a way to describe the structure of the language. We have no desire to use UML formally; we just borrowed the notation from UML
because we thought this would make the specification clearer.

I welcome the endeavor to make OWL 1.1 compatible with ODM. I believe, though, that this effort should be considered separately from
the core language definition and the structural specification of the language. The proper place to discuss and establish the
relationship between OWL 1.1 and ODM is the "MOF-Based Metamodel" document or any derivative of this document that we might produce
in the working group.

It really is beneficial to consider the two problems (and thus documents) separately. The core OWL 1.1 specification would thus be
as lightweight as possible and should just define the core structure of the language. The fact that we use a few diagrams to do so
should just help make the specification clear. We should make it explicit that this part of the specification says nothing about the
relationship between OWL 1.1 and ODM. We should also make a specific a pointer to the separate document which defines the official
metamodel and the relationship with ODM.

Sincerely yours,


> Elisa F. Kendal wrote:
> Hi Bijan and all,
> The Ontology Definition Metamodel (ODM) [1] was originally developed to 
> address some of the same issues that you, Boris, and others have 
> identified as the motivation behind the structural specification for OWL 
> 1.1, among others. We agree that this is a really valuable part of the 
> overall language specification, but think that this particular document 
> needs more scrutiny prior to publication from implementors in 
> particular, and are willing to assist with that work, as I mentioned in 
> a previous email. The end result will likely necessitate a revision to 
> the ODM, which should be maintained in sync with the OWL language 
> development process. We think that the OMG should remain the primary 
> home for some of this work, but, just as we did with the recently 
> published ISO Common Logic specification [2], we would be happy to have 
> the diagrams live in both places.
> Some of the areas of disconnect between the current ODM and proposed 
> structural specification include a well-defined relationship with RDF, 
> which Jeremy Carroll, Dave Reynolds, Pat Hayes, Chris Welty, Evan 
> Wallace, and others contributed to the specification.  We also 
> maintained support for OWL Full, which is important for some members of 
> our user base.  There are a number of implementations of the ODM already 
> available, including our Visual Ontology Modeler [3], IBM's Web Ontology 
> Manager and Integrated Ontology Development Toolkit [4] (among other IBM 
> projects), and several open source activities [5, 6, 7].  Thus, the 
> document should be reviewed not only by us (Sandpiper), but by other 
> stakeholders in the OMG community.
> We are comfortable with publication of the model theoretic semantics 
> document, but do not believe that either the structural specification or 
> MOF-based metamodel on which it depends (whose authors are members of 
> the OMG Ontology PSIG, who agree that it is merely a draft, and are 
> interested in participating the work) are ready to be published with 
> working draft status.
> Thanks,
> Elisa
> [1] http://www.omg.org/docs/ptc/06-10-11.pdf
> [2] 
> http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=39175
> [3] http://www.sandsoft.com/products.html
> [4] http://alphaworks.ibm.com/topics/semantics?open&S_TACT=105AGX01&S_CMP=LP
> [5] http://www.eclipse.org/m2m/atl/usecases/ODMImplementation/
> [6] 
> http://www.eclipse.org/modeling/mdt/eodm/docs/articles/EODM_Documentation/
> [7] http://cimtool.org/
> Bijan Parsia wrote:
> >
> > (It would be easier if you had made these fresh threads so we could  
> > collect the document discussion separate from the schedule  
> > discussion. Or you could have hung this off my [impr].)
> >
> > Thanks for the reviews. I find them helpful. The more the merrier.
> >
> > I have more detailed reply, but I want to point out a general  
> > perspective issue. The structural specification defines the language  
> > from a certain perspective. Jeremy sometimes calls this the "tree"  
> > view. This perspective has some advantages for certain classes of  
> > implementor (e.g., the OWL API and the KAON2 API map fairly closely  
> > into this document; even Jena has an "object oriented" view, I  
> > believe). It is also useful as a bridge to related languages and maps  
> > straightforwardly to an XML syntax (which is really nice for some  
> > less semantic web oriented applications of OWL, for making use of the  
> > XML tool chain, and for avoiding some grumbling from some XML heads).
> >
> > Given that the Abstract Syntax view is a pretty embedded piece of the  
> > current OWL (not to mention OWL 1.1) infrastructure, I think it needs  
> > to be maintained. This does not mean that the current document is  
> > appropriate for any end user, but, just as with the model theory, it  
> > is not intended to be.
> >
> > There has been some quite positive implementor feedback (e.g.,  
> > Matthew Horridge, who reimplemented the OWL API in the light of the  
> > structural specification and used it as a basis for Protege4). There  
> > are, of course, RDF based implementations (keying off the RDF mapping  
> > document); TopBraid Composer comes to mind.
> >
> > End user documentation is very important, but so are good tools. So,  
> > I ask that when we consider the formal specifications, that we keep  
> > in mind the need to support implementors, language lawyers, and  
> > people trying to extend OWL or design new useful services.
> >
> > Boris has a discussion of some of the issues he faced as an  
> > implementor in response to my [impr]:
> >     <http://lists.w3.org/Archives/Public/public-owl-wg/2007Oct/0085.html>
> Cheers,
> Bijan.
Received on Wednesday, 24 October 2007 15:47:12 UTC

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