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Re: Representing USE-OR in SKOS/XL/ISO25964

From: Osma Suominen <osma.suominen@helsinki.fi>
Date: Wed, 23 Apr 2014 09:52:20 +0300
Message-ID: <53576324.4090502@helsinki.fi>
To: public-esw-thes@w3.org
Hi Johan!

On 23/04/14 05:45, Johan De Smedt wrote:
> The iso-thes depicts the compound equivalence relationship as detailed
> in red below.
> This allows to infer the iso-thes:plusUseTerm and iso-thesUFTerm (USE+
> and UF+ respectively).See blue arrows.
> The iso-thes ontology provided USE+ and UF+ are extensions of
> skos-xl:labelRelation.
> Whereas the relationships (USE+ and UF+) exists among the terms (see
> iso-thes:plusUseTerm and iso-thesUFTerm respectively), no direct
> relation is inferred between the concepts ex:A (or ex:B) and the
> SplitNonPreferredTerm.

Thank you for the explanation and the picture.

However, you are only describing the USE+/UF+ case, which is well 
covered by ISO25964-1 and the iso-thes SKOS extension. USE+ means 
something like "to represent term X that is not in the thesaurus, use a 
combination of A AND B". So to retrieve information about "coal mining", 
which is not included in some example thesaurus, you can use a Boolean 
query "coal AND mining" (example from ISO85964-1, sect. 8.5). (The UF+ 
relationship is the exact inverse of USE+, I will skip it for brevity.)

What I was asking for is the subtly different case USE-OR, where the 
given term ("pitch" in the example) is not in the thesaurus, and can be 
given multiple interpretations from which only one should be chosen by 
the indexer/retriever (or possibly both, using Boolean OR). To 
understand the difference, consider a database indexed using a thesaurus 
which includes the concepts "pitch (sound)" and "pitch (steepness)". If 
the standard USE+ relation were used to map "pitch" to these qualified 
terms/concepts, then "pitch" could be represented using a Boolean query 
"pitch (sound) AND pitch (steepness)". But such a query would likely 
yield few results or none at all, because the meanings of the two 
concepts are very different and not many database records will mention 
them both if they have been properly indexed.

> So this does NOT cover the solution 2 and 3 statements making ex:pitch
> (“pitch”) an alt label of ex:A and of ex:B.

Sorry, I made a mistake in example 3 when I included altLabels (a 
copy-paste error). What I meant is this:

3. iso-thes SplitNonPreferredTerm with custom USE-OR property

ISO 25964 has a class SplitNonPreferredTerm which can be used to 
represent "an 'imagined' concept that may exist in a user’s mind but is 
not present in the thesaurus". Though this class is normally used with 
the USE+ relation, one could coin a custom USE-OR property (below called 
ex:orUseTerm) and use it instead, like this:

ex:A a skos:Concept ;
   skosxl:prefLabel ex:pitch_sound .

ex:B a skos:Concept ;
   skosxl:prefLabel ex:pitch_steepness .

ex:pitch_sound a skosxl:Label ;
   skosxl:literalForm "pitch (sound)"@en .

ex:pitch_steepness a skosxl:Label ;
   skosxl:literalForm "pitch (steepness)"@en .

ex:pitch a isothes:SplitNonPreferredTerm ;
   skosxl:literalForm "pitch"@en ;
   ex:orUseTerm ex:pitch_sound, ex:pitch_steepness .

Note that I am not using isothes:plusUseTerm here, but a similar custom 
property ex:orUseTerm, because I want to express OR alternatives, not an 
AND combination.


Osma Suominen
D.Sc. (Tech), Information Systems Specialist
National Library of Finland
P.O. Box 26 (Teollisuuskatu 23)
Tel. +358 50 3199529
Received on Wednesday, 23 April 2014 06:52:54 UTC

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