Models

Al,

Sorry, I had understood that there had been in the past some discussion of 
the 'concept-based model' underlying SKOS as opposed to the so-called 
'term-based model' underlying the approach of many thesaurus practitioners, 
so I assumed that these differences were already known. The kinds of 
information elements not covered by the SKOS core model are things like 
History note, Source, Definition, Status, Editorial Note, Date of input and 
Date last modified for a non-descriptor. In some use cases, for example in 
providing a full thesaurus to another institution for use at the second 
institution, or to an organization for translation of the thesaurus, these 
could be considered as essential data elements which would mitigate against 
use of SKOS. But I can certainly understand that in the context of the 
Semantic web these might not be considered important use cases.

In multilingual thesauri there is also the question of non-descriptors 
where there is an association between the non-descriptors, i.e. they 
describe a concept on the edge of the domain which has been treated as a 
non-descriptor not because there is not literary warrant for them to be 
considered as a concept in itself. For example, the OECD Macrothesaurus as 
developed by the OECD has Leeward Islands an a non-descriptor (though the 
concept is clearly defined, is distinct from other related concepts and can 
be expressed in several languages) simply because there is not enough 
material to justify it as a concept, though when it is used by the UN 
Economic Commission for Latin America and the Caribbean the non-descriptor 
is switched over to become a descriptor. In these cases, it may be useful 
to associate the different non-descriptors together in a single 
non-descriptor record (which represent a concept, no matter how you define 
concept). I hesitate to mention this case because the importance that I 
accord to this use is not shared by all my colleagues, but it may still be 
an important point of consideration for developers of some multilingual 
thesauri.

I hope this helps.

Ron

  At 22:03 28/02/2005, Miles, AJ \(Alistair\) wrote:
>Ron,
>
>Would you mind writing up in short exactly which parts of the BS8723 model 
>are not covered by the SKOS Core model?
>
>Thanks,
>
>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
>-----Original Message-----
>From: public-esw-thes-request@w3.org 
>[mailto:public-esw-thes-request@w3.org]On Behalf Of Ron Davies
>Sent: 27 February 2005 09:09
>To: public-esw-thes@w3.org; Thomas Baker
>Cc: public-esw-thes@w3.org
>Subject: Re: Quick Guide to Publishing a Thesaurus on the Semantic Web
>
>At 14:16 25/02/2005, Thomas Baker wrote:
>
>>Hmm, it feels to me that the notion of converting between XML
>>and RDF automatically opens a can of worms.  For starters,
>>what is an "XML version of a thesaurus"?  Such a document
>>could presumably take on any number of forms since the document
>>models expressible in XML are theoretically quite diverse.
>Even assuming that a conversion could be done automatically, there is also 
>the question of what information might be lost in doing so. The model 
>underlying SKOS, for instance, does not include all of the information in 
>the BS 8743 model, which might make it unsuitable for certain kinds of uses.
>
>Ron
>
>Ron Davies
>Information and documentation systems consultant
>Av. Baden-Powell 1  Bte 2, 1200 Brussels, Belgium
>Email:  ron(a)rondavies.be
>Tel:    +32 (0)2 770 33 51
>GSM:    +32 (0)484 502 393