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Re: revisions and change in skos

From: Aida Slavic <aida@acorweb.net>
Date: Mon, 29 Sep 2008 10:14:10 +0100
Message-ID: <48E09C62.1060207@acorweb.net>
To: De Smedt Johan <Johan.DeSmedt@wkb.be>
CC: Rob Tice <rob.tice@k-int.com>, public-esw-thes@w3.org


What is a 'version concept'? I am not sure is it only a casual use of the 
expression 'concept' instead of 'term' that causes problem - but it may be worth 
to be more precise...

 > - URI are forever
 > - the skos:Concept may be constraind in time using an applicability
 > period
 > - the skos Concept has a creation date. modification date and
 > version(=introduction version) property
 > - semantic relations are not versioned (skos would be more difficult to
 > accommodate that)
 > - Next to semantic relations, change-notes are used on versioned
 > concepts.
 >   These change notes contain references to earlier/newr versions of a
 > concept

concept is an idea - this is the level SKOS is supposed to capture by assigning 
an URI to this idea. New concepts can emerge - semantic field of on concept can 
split into to or two concepts can be merged to create a new concept. But in 
principle concepts themselves don't die, disappear, change - so in principle URI 
is forever.
For SKOS two concepts from two different KOS schemes are always two different 
concepts between which one can state the level of similarity. To what degree two 
vocabularies speaks of the same concepts can be stated through alignment/mapping 
- and is defined by the mapping relationship. But even when we state that two 
concepts means the 'same/equivalent' what is meant is that their semantic fields 
overlap sufficiently for us to safely operate with them as if they are the same.

Labels are sphere of practical use. Relationship between concepts and terms 
(labels) is  one to many. In real life have to add constraints to the use of 
labels (preferred term) or change label for practical reasons. Labels (i.e. 
relationship between concept and label) can become depricated within certain 
sphere of use and in certain time - but this has nothing to do with the concept 

To make it more complicated - in principle in information indexing and retrieval 
we need to preserve "the knowledge and the history of label/concept 
relationship" - simply because older recorded documents may have these labels 
used in the meaning that was relevant for the time when document was created.
Good example are geographical and geo-political entities, historical entities 
such as countries that don't exist anymore, political entities that existed in 
certain time on which we still have documents. Then also we need to know old and 
depricated term(s) for entities we now call differently in order to be able to 
retrieve information on them from the period when they were called differently.

I wonder whether my understanding here is correct - but I certainly don't want 
to distract Rob and others trying to a good job here.


Received on Monday, 29 September 2008 09:15:05 UTC

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