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Re: ISSUE 77 and postcoordination [and ISSUE-40!]

From: Jakob Voss <jakob.voss@gbv.de>
Date: Mon, 17 Mar 2008 10:57:31 +0100
Message-ID: <47DE408B.8050208@gbv.de>
To: public-esw-thes@w3.org
Cc: public-swd-wg@w3.org


Sorry for confusion and thanks for competent feedback!

Nabonita wrote:

 > As per my experience and understanding of library cataloguing and
 > subject indexing I agree with Leonard, Post-coordination is done
 > at the searching stage only.

Let me redefine my concert:

Up to now there is no standard way to encode COORDINATION with SKOS and 
that's a big problem.

Aida Slavic wrote:

> Practice so far shows that for formats used as 'carriers' of KOS for the 
> purpose of information retrieval - it is completely irrelevant whether 
> pre-coordiantion comes from the original vocabulary or whether 
> pre-coordination is created in the process of indexing.

Yes and semantically it is irrelevant whether coordination takes place 
in the pre- or post- way. Either you search for "X" and in the 
vocabulary "X" is a pre-coordination of "A" and "B" or you search for 
"A" and "B" by postcoordinating the concepts in your search. Both ways 
you should get all documents indexed with "A" and "B".

> how about the following view
> 1. We don't use SKOS to index - we use vocabulary to do so.
> The fact that vocabulary happen to be formatted in SKOS is irrelevant 
> for the process of indexing and information retrieval.
> 2. We use resource metadata (e.g. Dublin Core) to establish link between 
> resource and vocabulary. We do not use SKOS to represent this link ***

Then what's skos:subject for? Either we remove it from the SKOS standard 
or we fix it.

> 3. We use information retrieval system to make sense of links between 1. 
> resource 2. metadata describing it 3. vocabulary used to populate metadata.
> One resource is often indexed by more than one term from a single scheme 
> but that is not likely to be a problem if we have layers above properly 
> managed.

If you ignore this "layers above" then SKOS vocabularies are irrelevant 
at all. What do you want to do with a vocabulary encoded in SKOS but 
indexing resources?

Maybe we have different views about what a "KOS" exactely is. Let me 
phrase Wikipedia's definition of "Semantic" (I could also cite 
philosophers like Gottlob Frege):

"Semanticists generally recognize two sorts of meaning that an 
expression (such as the sentence, "John ate a bagel") may have: (1) the 
relation that the expression, broken down into its constituent parts 
(signs), has to things and situations in the real world as well as 
possible worlds, and (2) the relation the signs have to other signs, 
such as the sorts of mental signs that are conceived of as concepts."

Every RDF graph has only semantic in the second sense unless human 
beeings use it for some purpose in the real world. A KOS encoded in SKOS 
does not carry any practical meaning unless you know that it can be used 
for indexing resources.

Up to no there is no standard way (beside my proposal or ugly RDF 
reification) to encode that a given resource is indexed by a given 
person (plus at a given time, context..) with one or more given 
concepts. I find this a pretty mean situation.


P.S: I generally find the philosophical background and practical 
implications of SKOS and its usage very interesting and I think SKOS 
will bring back some forgotten results of information science but at the 
same time clean up some of its anachronisms ;-)

Jakob Vo▀ <jakob.voss@gbv.de>, skype: nichtich
Verbundzentrale des GBV (VZG) / Common Library Network
Platz der Goettinger Sieben 1, 37073 G÷ttingen, Germany
+49 (0)551 39-10242, http://www.gbv.de
Received on Monday, 17 March 2008 09:58:49 UTC

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