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Re: [PORT] Concept identification and reference

From: Carl Mattocks <carlmattocks@checkmi.com>
Date: Thu, 4 Nov 2004 11:27:29 -0500 (EST)
Message-ID: <15109.>
To: "Miles, AJ \(Alistair\)" <A.J.Miles@rl.ac.uk>
Cc: "'public-esw-thes@w3.org'" <public-esw-thes@w3.org>, "'public-swbp-wg@w3.org'" <public-swbp-wg@w3.org>

at Al :

Given this group is the source of best practice for using 'RDF
descriptions of existing thesauri ' I do not think you can be neutral.

Pragmatically, until all controlled vocabulary authors employ a common 
central / federated / peer to peer facility that helps them understand
when a concept has a URI , SKOS guidelines will have to explain ;

(1) the value of the 'owl:sameAs machinery' which enables multiple
published URIs to exist for the same concept
(2) how reference by description may be used to refer to such concepts
from other (RDF) descriptions.


<quote who="Miles, AJ (Alistair)">
> Hi all,
> I have a key issue to resolve ...
> Using thesauri as part of the semantic web depends on being able to
> uniquely
> reference a thesaurus concept within a global information space.
> The simplest way to uniquely reference a thesaurus concept is via a URI.
> However, very few (if any) thesauri have URIs assigned to their concepts.
> It is obviously a point of good practise to encourage thesaurus developers
> to assign and publish URIs for the concepts in the thesauri they are
> developing.  These concepts will then have 'official' URIs.  However, such
> a
> practise will take time to be implemented.
> In the mean time, we would like to be able to publish RDF descriptions of
> existing thesauri, for which there are no 'official' concept URIs.
> One practise has been, in this case, to make up unofficial URIs.  However,
> this practise can obviously lead to the proliferation of multiple URIs for
> the same concept.  Although the mechanisms obviously exist to cope with
> this, from a pragmatic point of view it might make sense to discourage
> this
> practise, unless absolutely necessary, where alternatives exist and it can
> be avoided.
> So what alternatives are there to making up unofficial URIs for concepts?
> One option is to encourage RDF descriptions of current thesauri where all
> concept nodes are blank nodes.  This can be facilitated within an RDF/XML
> description of a thesaurus, for example, by the use of the rdf:nodeID
> attribute.
> An RDF description of a thesaurus with all concept nodes as blank nodes at
> least means that a machine readable description of the thesaurus exists,
> and
> can be imported between applications.  And so a partial goal is satisfied
> ...
> However, it does not solve the problem of how a person might, for example,
> refer to one of these concepts as part of the RDF description of a web
> document.
> In this case, there is a possibility to use 'reference by description'.
> The
> mechanism for unique identification of concepts within a print environment
> is traditionally via the preferred term (or 'descriptor') for that
> concept,
> which is a unique term within a thesaurus.  The combination of the
> preferred
> term for a concept, and a URI identifying the thesaurus, therefore
> provides
> a globally unique description of a concept.
> The problem here is that, whereas reference by description for people in
> FOAF can be satisfied by a single property (e.g. foaf:mbox), for which the
> inverse-functional property machinery in OWL provides an implementation,
> reference by description for concepts as described above depends on at
> least
> two properties (e.g. combination of skos:prefLabel and skos:inScheme), for
> which implementations would depend on the expression of identity rules.
> So the choice I see boils down to:
> When describing best practise for creating RDF descriptions of thesauri
> without official URIs, do we ...
>  (a) attempt to remain neutral about whether people make up unofficial
> URIs,
> and rely on the owl:sameAs machinery to cope with multiple published URIs
> for the same concept, or ...
>  (b) actively encourage the publication of these thesauri with concept
> nodes
> as blank nodes, and additionally publish guidelines on how reference by
> description may be used to refer to such concepts from other RDF
> descriptions (which may depend on rules technology without any current
> standard implementations).
> What do you think ???
> Al. ~:)
> ---
> 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

Carl Mattocks

co-Chair OASIS (ISO/TS 15000) ebXMLRegistry Semantic Content SC
co-Chair OASIS Business Centric Methodology TC
v/f (usa) 908 322 8715
Semantically Smart Compendiums
Received on Thursday, 4 November 2004 16:27:30 UTC

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