[tdwg-content] FOAF [SEC=UNCLASSIFIED]

Thu Nov 4 06:21:27 CET 2010

There are a few pages about this.

I am finding that the version available at http://xmlns.com/foaf/spec/index.rdf reads into Protege ok, and the HermiT reasoner does not complain about it - that being my usual test. The Owl consistency checker at http://www.mindswap.org/2003/pellet/demo.shtml  highlights a couple of DL issues.

* Some of the social properties (icq, msn chat, etc) are functional inverse datatype properties (if two persons have the same ICQ number, then they are the same person). The problem is that there is no general way to check data literals for equality (the OLW spec, for instance, supports fractions, floats and doubles). But these properties can be blithely ignored in most cases by simple dint of not using them.
* name is declared to be a subtype of rdfs:label, but rdfs:label is an annotation property
* the vocabulary does not import its dependencies, and so some declarations are implied

Annotation properties are a bit of a bugbear. As far as I can tell, if something is an annotation property then it should only be used to describe vocabulary terms. The actual subject matter of an ontology should be described with regular properties. Thus, declaring name to be a subproperty of label is simply wrong: a thing's name is ontology, not vocabulary. The machine-level issue is that RDF can't tell the difference between the two, so OWL/RDF cannot behave according to the OWL specification in certain respects. But dcterms title and description fit the bill admirably, anyway.

You can use the FOAF properties and classes without explicitly importing FOAF - you can just declare them. The OWL-DL incompatibilities are not serious. On the other hand ... you may dislike the fact that there are rules in FOAF at all. Maybe two different people happen to share an organisational ICQ address. FOAF at the moment would force you to create a Organisation or Group object for the team, and assign the ICQ address to that.

And so yes, there are issues. The simple way to deal with it is to create TDWG terms mimicking the FOAF terms, declare them to be sameAs, and if that becomes unworkable then to break the equivalence.

On 03/11/2010, at 3:55 PM, Bob Morris wrote:

> If machine reasoning is a goal, I would be wary of FOAF.  An OWL2-DL, or other OWL2 tractable reasoning profile, version remains a moving target, to the best of my knowledge.  The reasons that http://xmlns.com/foaf/spec/ is not subject to tractable reasoning are relatively manageable, but I can no longer find the Zimmerman proposal for a FOAF DL version referenced in the thread ending at http://lists.w3.org/Archives/Public/public-lod/2010Jul/0378.html
> 
> Can someone point me at a DL version of FOAF and indication that it is actively under discussion somewhere?
> 
> Thanks
> 
> 
> On Tue, Nov 2, 2010 at 10:38 PM, Richard Pyle <deepreef at bishopmuseum.org> wrote:
> 
> I was thoroughly delighted to learn recently that FOAF uses terms in almost
> exactly the same way that I had structured my "Agents" data (right down to
> the same exat terms, in most cases).  I plan to move forward with the FOAF
> terms that are relevant (thanks to John W. for pointing this out to me at
> TDWG).
> 
> Rich
> 
> > -----Original Message-----
> > From: tdwg-content-bounces at lists.tdwg.org
> > [mailto:tdwg-content-bounces at lists.tdwg.org] On Behalf Of Paul Murray
> > Sent: Tuesday, November 02, 2010 4:18 PM
> > To: Steve Baskauf
> > Cc: tdwg-content at lists.tdwg.org
> > Subject: Re: [tdwg-content] Comments on Cam's RDF practical
> > details of recording a determination What is an Occurrence?
> > [SEC=UNCLASSIFIED]
> >
> >
> > On 29/10/2010, at 12:41 AM, Steve Baskauf wrote:
> >
> > > I think both dwc:recordedBy for the Occurrence and
> > dcterms:created for some tokens should be provided.
> > Depending on the situation, they might be different entities
> > (I think John Wieczorek pointed this out in an earlier
> > thread).  dwc:recordedBy is specifically supposed to be a
> > person whereas I think dcterms:creator could be a person or
> > an institution.
> >
> > Perhaps it might be worthwhile leveraging the FOAF vocabulary
> > (Friend of a Friend). It's mainly meant for social
> > networking, but nevertheless it does contain terms such as
> > Person, Organisation, Group and Project. (Project is
> > interesting - collection activities perhaps are FOAF Projects).
> >
> > The spec is here: http://xmlns.com/foaf/spec/
> >
> > We can envisage the day where, by following links on
> > taxonomic web pages, you could eventually find an Author's
> > current twitter address, or ask the semantic web "find me all
> > specimens of genus Tandanus collected by teams affiliated
> > with the university of NSW between 2005 and 2007".
> >
> >
> >
> >
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> 
> -- 
> Robert A. Morris
> Emeritus Professor  of Computer Science
> UMASS-Boston
> 100 Morrissey Blvd
> Boston, MA 02125-3390
> Associate, Harvard University Herbaria
> email: morris.bob at gmail.com
> web: http://bdei.cs.umb.edu/
> web: http://etaxonomy.org/mw/FilteredPush
> http://www.cs.umb.edu/~ram
> phone (+1) 857 222 7992 (mobile)
> 

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