RE: URI thoughts

> > Assuming I have a RDF model of the follows.
> >
> > @prefix rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns#.
> > @prefix dctype: http://dublincore.org/2003/12/08/dctype#
> >
> > <http://www.charlestoncore.org/images/group-logo.png> 
> rdf:type dctype:Image.
> >
> > A simple model without any closure will contain only this one 
> > statement.  It is not very useful, because given this 
> model, I cannot 
> > even write a program to tell a human that the resource 
> > http://www.charlestoncore.org/images/group-logo.png is a 
> "type" of "Image".
> > Note, the type and Image are annonated in their respective RDF 
> > document via rdfs:label.  Without dereferencing the URI, 
> you won't be 
> > able to obtain how to label the graph and discribes it to a human.
> >
> > Different types of closure gives you different scope of knowledge 
> > base, from which different answers may be given to the same query.
> 
> Absolutely, what I'm suggesting is a framework where the 
> extent / scope of the closure is designated (to some extent) 
> by the author of the instance graph as well as the authors of 
> defining ontologies.  In which case, the RDF model above 
> would instead be:

Yes, I think a standard mechanism to designate the closure is needed.
 
> @prefix rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns#.
> @prefix dctype: http://dublincore.org/2003/12/08/dctype#.
> @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>.
> 
> <> rdfs:isDefinedBy <http://purl.org/dc/dcmitype/>.
> 
> <http://www.charlestoncore.org/images/group-logo.png> 
> rdf:type dctype:Image.
> 
> Note the difference in the dctype base uri in the instance 
> document and the URL of the defining RDF schema.  
> <http://purl.org/dc/dcmitype/> is a PURL.org URL which 
> redirects (currently) to <http://dublincore.org/2003/12/08/dctype#>.

It is my mistake.  I should not use the
http://dublincore.org/2003/12/08/dctype# URI.  It should be the purl URI.  I
just carelessly copied from my browser's location.  The resource of
http://dublincore.org/2003/12/08/dctype#Image in fact doesn't exist.  
 
As a side point, this raises an interesting question that I have wondered
before.  For URIs that have a fragment identifier.  An HTTP get won't get a
400+ response even if the requested resource doesn't exist. The
http://dublincore.org/2003/12/08/dctype#Image, for instance, is just such a
case.   An RDF engine must parse the retrieved document before figuring it
out. Something seems not right here. I wonder if any of you have the
knowledge to enlighten me here regarding the supposed treatment.

Xiaoshu

Received on Wednesday, 21 June 2006 12:52:34 UTC