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RE: ISSUE-160: Allowing collections in semantic relationships

From: Tudhope D S (AT) <dstudhope@glam.ac.uk>
Date: Sun, 16 Nov 2008 12:56:39 -0000
Message-ID: <0BA7EE4D4646E0409D458D347C508B780419AFF4@MAILSERV1.uni.glam.ac.uk>
To: "Alistair Miles" <alistair.miles@zoo.ox.ac.uk>
Cc: <public-swd-wg@w3.org>
Hi Al
thanks for getting back
I take your points about indexing and correspondence between SKOS and BSI.
However, they don't address the main issue I wanted to raise. I see your personal note deals with it more and I think indicates that this issue is still somewhat under consideration?
I may have confused things by suggesting a work around. Let's set aside the non-indexing issue for now.
I'll restate the issue:
Concern: Insufficient support/guidance for legacy systems wrt guide terms / facet indicators
My concern is that SKOS collections do NOT represent common practice in most existing thesauri
and (if this is true) there is a danger that they might constitute a significant barrier to take up of SKOS by vocabulary owners who would otherwise wish to do so, unless appropriate guidance/alternatives are available.
I think conversion of legacy thesauri to SKOS is an important application for SKOS and its wider take up.
Do we know how many thesauri actually follow the SKOS collections for such structures? 
I don't think I know of any though I expect a few exist.
Most that I know incorporate facet indicators as part of the hierarchy.  (I'm happy to be corrected if this not the case)
What do we expect vocabulary owners who do not follow the SKOS collections semantics to do?
If we expect them to change their vocabulary structure is that a realistic expectation?
The same concern applies to BSI. My understanding of the BSI data model is that the 'custom attribute' of a concept could potentially serve the function of helping legacy vocabularies with regard to (not implementing) collections.
I personally like the SKOS collections semantics but the issue is a concern because I'd like to see wide take up of SKOS by existing vocabularies. Successful standards need to strike a balance between best practice and legacy practice. Antoine's extensions [your ref 6 below] seem to go towards meeting this issue thought I'm not sure what their status is?
I think though at least some guidance is needed in the primer with some suggestions for what to do if legacy vocabularies owners do not want to completely restructure for guide terms/facet indicators. Maybe this could be considered for final primer version?



From: Alistair Miles [mailto:alistair.miles@zoo.ox.ac.uk]
Sent: Thu 06/11/2008 09:34
To: Tudhope D S (AT)
Cc: public-swd-wg@w3.org
Subject: ISSUE-160: Allowing collections in semantic relationships

Dear Doug,

Thank you for your support and your helpful comments. In response to
the comment below:

On Sat, Oct 04, 2008 at 01:54:26PM +0000, SWD Issue Tracker wrote:
> ISSUE-160: Allowing collections in semantic relationships
> http://www.w3.org/2006/07/SWD/track/issues/160
> Raised by: Antoine Isaac
> On product: All
> Raised by Doug Tudhope in [1]
> While SKOS collections represents best practice in thesaurus construction, many
> prominent existing thesauri (and related KOS) do not follow the SKOS collections
> semantics. Instead, they model guide terms, facet indicators etc as part of a
> hierarchy using standard Broader/Narrower relationships. This creates a problem
> in converting such existing KOS into SKOS. From discussions it appears other
> people have come to a similar judgment in converting such cases to SKOS - being
> reluctant to change the existing structure of a KOS designed by a third party.
> The pragmatic decision is often to create a (nonSKOS) property of a concept, to
> say essentially, 'NOT_FOR_INDEXING'. This allows a basic distinction to be made
> between a facet indicator (or guide term) and a concept available for indexing.
> Can we consider if something like this could be introduced into SKOS to
> facilitate conversion of many legacy KOS? The primer can always encourage the
> full collections approach as best practice.

The requirement to indicate that some concepts are not intended for
use in indexing was raised in the SKOS Use Cases and Requirements
document [2]. Meeting this requirement was then discussed as
ISSUE-46. The working group resolved to close this requirement because
all matters related to indexing were deemed out of scope for SKOS, and
better treated by vocabularies such as Dublin Core [3] or other third
party vocabularies. We propose to make no change to the SKOS
Reference, can you live with this?

Kind regards,


Personal comment by Alistair: I realise that the treatment of KOS
elements such as guide terms, facet indicators and node labels, and
the choice of whether to use the SKOS collections framework or whether
model as you describe, remains a difficult issue, and requires careful
judgment. However, on a positive note, I was pleased to learn recently
of the very close correspondance between the modeling of node labels
in the BS 8723-5 UML model and the modeling of collections in
SKOS. Nicolas Cochard did an excellent job of illustrating the
alignment between these two models at the ISKO event in July [4,5]. I
hope that extensions to SKOS and best practices based on the new BS
8723-5 data model will help to clear up some of the difficulties here
in the near future.

See also Antoine's message [6] for some suggestions for the
development of extensions to meet your requirement.

[1] http://lists.w3.org/Archives/Public/public-swd-wg/2008Oct/0062.html
[2] http://www.w3.org/TR/2007/WD-skos-ucr-20070516/#R-IndexingAndNonIndexingConcepts
[ISSUE-46] http://www.w3.org/2006/07/SWD/track/issues/46
[3] http://www.w3.org/2008/05/07-swd-minutes.html#item10
[4] http://www.iskouk.org/presentations/cochard_BS8723-exchange-format.pdf
[5] http://www.iskouk.org/SKOS_July2008.htm
[6] http://lists.w3.org/Archives/Public/public-swd-wg/2008Oct/0286.html

Alistair Miles
Senior Computing Officer
Image Bioinformatics Research Group
Department of Zoology
The Tinbergen Building
University of Oxford
South Parks Road
United Kingdom
Web: http://purl.org/net/aliman
Email: alistair.miles@zoo.ox.ac.uk
Tel: +44 (0)1865 281993

----- End forwarded message -----

Alistair Miles
Senior Computing Officer
Image Bioinformatics Research Group
Department of Zoology
The Tinbergen Building
University of Oxford
South Parks Road
United Kingdom
Web: http://purl.org/net/aliman
Email: alistair.miles@zoo.ox.ac.uk
Tel: +44 (0)1865 281993
Received on Sunday, 16 November 2008 12:57:22 UTC

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