RE: Global concept identification and reference

Hi Leonard,

Just to say first of all, thanks for taking the time here, this sort of
discussion is really valuable I think.

> If different people hold copies of the thesaurus at different 
> URLs, then 
> even your more long-winded RDF specification above will point to 
> different places. Is it only pointers to the concept level 
> that count as 
> URIs and have to be avoided, or can a pointer at the scheme 
> level also 
> be a URI for the scheme. In that case don't you have the same 
> problem of 
> people making them up?

Just to explain this a bit more (although this is RDF-specific stuff which
you may want to skip) ...

I still think that assigning URIs for concepts is by far the best option,
and the format for assigning concept URIs that you describe below is
perfectly acceptable.

The point of the following code snippet ...

<rdf:RDF>
  <skos:Concept>
    <skos:prefLabel>bananas</skos:prefLabel>
    <skos:inScheme>
      <skos:ConceptScheme>
        <foaf:homepage rdf:resource="[someURL]"/>
      </skos:ConceptScheme>
    </skos:inScheme>
  </skos:Concept>
</rdf:RDF>

... is to illustrate that it is possible to uniquely identify both a concept
and the scheme to which it belongs, without recourse to URIs specifically
assigned to these things (in the same way that it is possible to uniquely
identify a person without needing URIs, by reference to some uniquely
identifying property such as their email address).

I.e. I *could* describe in RDF a concept from the AAT, even though there are
no URIs for the AAT or any AAT concepts that have been endorsed by the
Getty, e.g. ...

<rdf:RDF>
  <skos:Concept>
    <skos:prefLabel>Adirondack chairs</skos:prefLabel>
    <skos:inScheme>
      <skos:ConceptScheme>
        <foaf:homepage
rdf:resource="http://www.getty.edu/research/conducting_research/vocabularies
/aat/"/>
      </skos:ConceptScheme>
    </skos:inScheme>
  </skos:Concept>
</rdf:RDF>

... this snippet of RDF translated into human speak says: 'the concept with
preferred label "Adirondack chairs" from the concept scheme whose homepage
is at http://www.getty.edu/research/conducting_research/vocabularies/aat/'
... 

(I.e. the URL in this example is the URL of the AAT homepage, and *not* the
URL of a machine readable description of the AAT, which of course would
create problems as you describe above).

I guess the point is that, for certain types of entity (such as people) it
may make better sense in RDF to use existing methods of identification (such
as mailbox or homepage for people) rather than attempting to use URIs.  What
I am exploring here is whether this is a useful or viable option for
thesauri and thesaurus concepts.

Yours,

Alistair.


> 
> Certainly as thesauri exist on the Web at the moment it is 
> not generally 
> possible to address a specific concept directly, so you 
> cannot usually 
> create URIs for concepts. I presume that if they are 
> presented with SKOS 
> encoding that will be possible. If the encoding is of the form 
> [schemeURL]#bananas, using the preferred label after the #, then this 
> seems to create a unique URI for the concept, whoever uses it.
> 
> However no doubt there are more complications in the way 
> these schemes 
> will be interpreted and manipulated which I am not familiar 
> with, so I'm 
> happy to leave the encoding to you RDF folk..
> 
> >Do you mind if I forward this email to public-esw-thes?  
> Seems like it might
> >be useful.
> 
> Yes, certainly, if you think it of general interest and not just your 
> explaining the rudiments to someone outside the general field of the 
> discussion.
> 
> Leonard
> -- 
> Willpower Information       (Partners: Dr Leonard D Will, 
> Sheena E Will)
> Information Management Consultants              Tel: +44 
> (0)20 8372 0092
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> L.Will@Willpowerinfo.co.uk               
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> ---------------- <URL:http://www.willpowerinfo.co.uk/> 
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>

Received on Wednesday, 10 November 2004 12:34:02 UTC