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[SKOS] subsection of Primer about ISSUE-36

From: Antoine Isaac <aisaac@few.vu.nl>
Date: Sun, 14 Dec 2008 20:09:02 +0100
Message-ID: <494559CE.4000803@few.vu.nl>
To: SWD WG <public-swd-wg@w3.org>

Hi everyone,

About the following action:

>    [PENDING] ACTION: Antoine propose 1 or 2 SPARQL examples showing
>    named graph usage [recorded in
>    [36]http://www.w3.org/2008/11/25-swd-minutes.html#action14]

I'd like to propose to add to the Primer the sub-section below (it would be at the very end of the Primer).
I hope this capture the spirit of our resolution for ISSUE-36 [1] appropriately, while not going too much in the direction of not yet stabilized practices.

Feedback of the WG is highly welcome!



[1] http://www.w3.org/2006/07/SWD/track/issues/36


5.3 SKOS, RDF Datasets and Information Containment

In a context of networked KOSs, some applications may require tracking provenance or ownership of SKOS statements, for instance for trust purposes. A specific issue is how to establish explicit links between a concept scheme and every piece of information that is stated in the original KOS it represents, including for instance semantic relationships between concepts. 

Such functionality, albeit identified as a candidate requirement [SKOS-UCR], is currently outside the scope of SKOS. In RDF, statements comes as context-free triples, which makes it difficult to represent containment and provenance.

However, solutions for such problems have been proposed, like named graphs [NAMED-GRAPHS], and the use of RDF Datasets in SPARQL [SPARQL]. A SKOS concept scheme can be related to an RDF Dataset, or even asserted to be such a Dataset, which enables to create SPARQL queries dealing with some form of provenance/containment. Continuing the example of Section 3.2, and assuming that ex1:referenceAnimalScheme and ex2:catScheme have been managed as appropriate RDF Datasets (here, named graphs), the query

SELECT  ?x ?y
FROM NAMED <ex2:catScheme>
WHERE   { ?x skos:broader ?y }

may return (ex2:abyssinian, ex1:cat) as a result, while this tuple would not appear among the results of 

SELECT  ?x ?y
FROM NAMED <ex1:referenceAnimalScheme>
WHERE   { ?x skos:broader ?y }

Readers should nevertheless be aware that these mechanisms have not been widely used at the time of writing, and that different standard practices could emerge in the future.
Received on Sunday, 14 December 2008 19:09:40 UTC

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