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Re: Top three levels of Dewey Decimal Classification published as linked data

From: Bernard Vatant <bernard.vatant@mondeca.com>
Date: Thu, 20 Aug 2009 23:43:12 +0200
Message-ID: <4A8DC370.5050108@mondeca.com>
To: "Panzer,Michael" <panzerm@oclc.org>
CC: Ed Summers <ehs@pobox.com>, public-lod@w3.org
Michael

Thanks for this very interesting and detailed explanation. I guess Ed 
and myself were not fully aware of multilingual variations of DDC. At  
least I was not.
And this is indeed food for thought for other cases of multilingual 
linked data. If DBpedia goes multilingual, I guess there will rise the 
same kind of issue.

Some remarks below
> Going back the the premise, I thing the question is here: What is
> http://dewey.info/class/641/? Is it a SKOS concept? If we analyse a
> couple of triples from the response we can determine what a user agent
> might learn from the answer of the service:
>
> <http://dewey.info/class/641/2009/08/about.en>
>     dct:isVersionOf <http://dewey.info/class/641/> .
> <http://dewey.info/class/641/2009/08/about.de>
>     dct:isVersionOf <http://dewey.info/class/641/> .
> ...
> <http://dewey.info/class/641/2009/08/about.es>
>     dct:isVersionOf <http://dewey.info/class/641/> .
>
> It is true that http://dewey.info/class/641/ is never mentioned in
> subject position, but it is in object position several times. So an
> agent might deduce the following about http://dewey.info/class/641/ from
> the response:
>
> <http://dewey.info/class/641/>
>     dct:hasVersion <http://dewey.info/class/641/2009/08/about.en> ;
>     dct:hasVersion <http://dewey.info/class/641/2009/08/about.de> ;
> ...
>     dct:hasVersion <http://dewey.info/class/641/2009/08/about.es> .
>   
Indeed. But you can't infer from this the type of  
<http://dewey.info/class/641/> AFAIK
Unless some extension of dcterms + SKOS would include some rule like
(?y  a skos:Concept  AND  ?x   dct:hasVersion  ?y) => (?x  a skos:Concept)
> And this coincides with what we get if we use a SPARQL query directly:
>   
Well, not exactly. How the SPARQL query retrieves the following triple 
is a mystery to me.
It figures I don't know which query is hiding behind DESCRIBE ...

<http://dewey.info/class/641/> rdf:type skos:Concept 


> I agree that it is somewhat misleading to not give this information when
> dereferencing http://dewey.info/class/641/. So do you think the results
> of a DESCRIBE query should always be included for any given URI in a
> linked data service? Should (all) triples be included also where the URI
> is used in object position? Would you think it is misleading to give
> more information?
>   
In a linked data perspective as I understand it, I would say quickly and 
naively that triples in the local graph where the resource is in subject 
position should be retrieved when dereferencing the URI, and if not all 
of them, a minima the resource type.

But it's a really good question!

Bernard

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*Bernard Vatant
*Senior Consultant
Vocabulary & Data Engineering
Tel:       +33 (0) 971 488 459
Mail:     bernard.vatant@mondeca.com <mailto:bernard.vatant@mondeca.com>
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Received on Thursday, 20 August 2009 21:44:14 UTC

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