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FW: SKOS 'concept schemes' and DCMI 'vocabulary encoding schemes'

From: Miles, AJ \(Alistair\) <A.J.Miles@rl.ac.uk>
Date: Mon, 10 Oct 2005 17:13:30 +0100
Message-ID: <677CE4DD24B12C4B9FA138534E29FB1D0ACDC2@exchange11.fed.cclrc.ac.uk>
To: <public-esw-thes@w3.org>

Hi all,

Sorry, should have cced this here when it was sent, comment on DCMI recommendations and aligning 'vocabulary encoding schemes' with 'concept schemes' ...

> -----Original Message-----
> From: Miles, AJ (Alistair) 
> Sent: 10 October 2005 16:07
> To: 'DC-RDF-TASKFORCE@JISCMAIL.AC.UK'
> Subject: SKOS 'concept schemes' and DCMI 'vocabulary encoding 
> schemes' 
> 
> 
> Hi all,
> 
> Just writing this up after thoughts at DC2005...
> 
> The problem:
> 
> Current qualified DC in RDF [1] recommends two patterns for 
> use of dc:subject ...
> 
> ---
> @prefix skos: <http://www.w3.org/2004/02/skos/core#> .
> @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
> @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
> @prefix owl: <http://www.w3.org/2002/07/owl#> .
> @prefix dc: <http://purl.org/dc/elements/1.1/> .
> @prefix dcterms: <http://purl.org/dc/terms/> .
> 
> # DCMI Pattern 1:
> 
> <http://www.example.com/somedoc> dc:subject [
>   rdf:value '19D10';
>   rdfs:label 'Algebraic K-Theory of spaces';
>   rdfs:isDefinedBy <http://www.example.com/somedefiningresource>;
> ]. 
> 
> # DCMI Pattern 2:
> 
> <http://www.example.com/somedoc> dc:subject [
>   rdf:value 'D08.586.682.075.400';
>   rdfs:label 'Formate Dehydrogenase';
>   rdf:type dcterms:MESH;
> ].
> 
> # ... where ...
> 
> dcterms:MESH rdf:type rdfs:Class, dcterms:SubjectScheme;
>   rdfs:isDefinedBy <http://purl.org/dc/terms/>.
> ---
> 
> The usual pattern for declaring properties or classes in an 
> RDFS vocabulary is the following pattern:
> 
> ---
> @prefix eg: <http://www.example.com/eg#>
> 
> # RDFS pattern:
> 
> eg:aProperty rdf:type rdf:Property;
>   rdfs:label 'a property';
>   rdfs:isDefinedBy <http://www.example.com/eg>.
> 
> eg:aClass rdf:type rdfs:Class;
>   rdfs:label 'a class';
>   rdfs:isDefinedBy <http://www.example.com/eg>.
> ---
> 
> In OWL the pattern is the same, with a bit extra:
> 
> ---
> # OWL pattern:
> 
> eg:anObjectProperty rdf:type owl:ObjectProperty;
>   rdfs:label 'a property';
>   rdfs:isDefinedBy <http://www.example.com/eg>.
> 
> eg:aClass rdf:type owl:Class;
>   rdfs:label 'a class';
>   rdfs:isDefinedBy <http://www.example.com/eg>.
> 
> <http:www.example.com/eg> a owl:Ontology.
> ---
> 
> For declaring 'concepts' and 'concept schemes' using SKOS we 
> wanted to follow the same pattern as RDFS/OWL, i.e.:
> 
> ---
> # SKOS Pattern:
> 
> eg:aConcept rdf:type skos:Concept;
>   skos:prefLabel 'love';
>   skos:inScheme <http://www.example.com/conceptscheme>.
> 
> <http://www.example.com/conceptscheme> a skos:ConceptScheme.
> ---
> 
> The reason we added skos:inScheme (rather than just 
> recommending usage of rdfs:isDefinedBy) was to allow for the 
> possibility that a concept participates in more than one scheme.  
> 
> The DCMI pattern 1 fits with RDFS pattern, OWL pattern and 
> SKOS pattern.  However, DCMI pattern 2 doesn't.
> 
> I suggest that DCMI:
> 
>  - drops the notion of allowing a 'subject scheme' to also be 
> a 'class of values', 
> 
>  - drops the recommendation to use rdf:type to link a 
> 'subject' to a 'subject scheme', 
> 
>  - recommends only pattern 1, not pattern 2.
> 
> So then, the example expressed using DCMI pattern 2 above 
> would simply become:
> 
> ---
> <http://www.example.com/somedoc> dc:subject [
>   rdf:value 'D08.586.682.075.400';
>   rdfs:label 'Formate Dehydrogenase';
>   rdfs:isDefinedBy dcterms:MESH;
> ].
> 
> # ... where ...
> 
> dcterms:MESH rdf:type dcterms:SubjectScheme;
>   rdfs:isDefinedBy <http://purl.org/dc/terms/>.
> ---
> 
> That's my two cents.
> 
> Cheers,
> 
> Al.
> 
> 
> [1] http://dublincore.org/documents/2002/05/15/dcq-rdf-xml/
> 
> 
> 
> ---
> Alistair Miles
> Research Associate
> CCLRC - Rutherford Appleton Laboratory
> Building R1 Room 1.60
> Fermi Avenue
> Chilton
> Didcot
> Oxfordshire OX11 0QX
> United Kingdom
> Email:        a.j.miles@rl.ac.uk
> Tel: +44 (0)1235 445440
> 
> 
Received on Monday, 10 October 2005 16:14:55 GMT

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