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RE: SKOS & SIMILE, concepts, terms, URIs, mappings

From: Miles, AJ (Alistair) <A.J.Miles@rl.ac.uk>
Date: Wed, 9 Jun 2004 18:11:23 +0100
Message-ID: <350DC7048372D31197F200902773DF4C049442EE@exchange11.rl.ac.uk>
To: "'Butler, Mark'" <mark-h.butler@hp.com>, "(www-rdf-dspace@w3.org)" <www-rdf-dspace@w3.org>
Cc: "'public-esw-thes@w3.org'" <public-esw-thes@w3.org>

Hi Mark, 

In reply to this question ...

> - how can you provide versions of an altLabel in multiple languages?
> BTW, I did discuss with Damian Steer, and he pointed out the multiple
> language problem could be solved using bNodes. 

This needs careful analysis.  The effort in SKOS has been to be utterly
clear about which nodes in the graph represent a piece of meaning (concept),
and which represent lexical or symbolic labels.  

So it is entirely reasonable to say something like ...

	<skos:Concept rdf:nodeID="a">
		<skos:prefLabel xml:lang="en">Cats</skos:prefLabel>
		<skos:prefLabel xml:lang="fr">Chats</skos:prefLabel>

... but to say something like ...

	<skos:Concept rdf:nodeID="b">
			<rdf:Description rdf:nodeID="c">
				<rdf:value xml:lang="en">Cats</rdf:value>
				<rdf:value xml:lang="fr">Chats</rdf:value>

... would break the whole model, because what does the "c" node represent?
The only reasonable interpretation is that it is a piece of meaning, because
the only thing that connects the two strings is their received meaning.  And
so we now have a concept as the value for a labelling property!!! 

The correct (first) example above uses the 'multilingual labelling approach'
(see [1]), which is essentially the rough and ready way of doing
multilingual thesauri.  To be more precise about modelling these sorts of
structures, one needs to take the 'interlingual mapping approach' as in e.g.

	<skos:Concept rdf:nodeID="a">
		<skos:prefLabel xml:lang="en">Cats</skos:prefLabel>

	<skos:Concept rdf:nodeID="b">
		<skos:prefLabel xml:lang="fr">Chats</skos:prefLabel>

	<rdf:Description rdf:nodeID="a">
		<skos-map:exactMatch rdf:nodeID="b"/>

Note that the mapping statement does not necessarily follow from the fact
that 'chats' is the usual french translation of the english word 'cats'.  If
I added the statement ...

	<skos:Concept rdf:nodeID="a">
		<skos:altLabel xml:lang="en>Cool dudes</skos:altLabel>

... it would become obvious that the mapping statement is in fact entirely
incorrect - that what the "a" node actually intends is something completely
different from the concept of the furry things that purr.

Anyway, hope this helps :) 


Alistair Miles
Research Associate
CCLRC - Rutherford Appleton Laboratory
Building R1 Room 1.60
Fermi Avenue
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 Butler, Mark
> Sent: 08 June 2004 14:51
> To: (www-rdf-dspace@w3.org)
> Cc: 'public-esw-thes@w3.org'
> Subject: RE: SKOS & SIMILE, concepts, terms, URIs, mappings
> Hi Alistair
> > I have some ideas about how to express lexical mappings 
> > that does not require the altLabels to have their own URI.
> I would be interested to hear your proposals here?
> Here is the use case we had in SIMILE:
> I have some Artstor data that uses the term "cadavers" (which 
> is a preferred
> term in the Artstor data), and I want to map onto the LOC TGM 
> thesaurus. In
> LOC TGM, cadavers is an alternative term for both "dead 
> animals" and "dead
> persons". Therefore, my guess is LOC decided that the term 
> "cadavers" was
> ambiguous, so they decided to encourage cataloguers to use 
> the two less
> ambiguous terms. However here the concept corresponding to cadaver is
> actually the union of the concepts that have "dead animals" and "dead
> persons" as their primary terms. 
> So if I want to create a mapping between the Artstor data and 
> the LOC TGM,
> how should I do it using SKOS for the record that uses the 
> term "cadavers"?
> I think I want a semantic mapping here, even though I am mapping to an
> alternative term?
> As well as the use case above, I think there are a number of 
> other things
> that seem difficult due to not giving altLabels their own 
> URIs - perhaps you
> also have workarounds for them?
> - how can you provide versions of an altLabel in multiple languages?
> - lots of web APIs (for example fetch, the Longwell and 
> Brownsauce browsers)
> use URIs to identify objects. Is there a way of identifying 
> altLabels that
> is compatible with these APIs?
> BTW, I did discuss with Damian Steer, and he pointed out the multiple
> language problem could be solved using bNodes. This doesn't 
> help the web API
> problem, but FOAF uses bNodes in a similar way, so some web 
> APIs are coming
> up with ways to solve the problem for the FOAF case, so perhaps an
> alternative solution might be to use a bNode?
> > RE: lexical mappings
> > This is splitting hairs a little bit, but I think it would 
> > be more accurate to say that a lexical mapping may or may 
> > not reflect a close semantic mapping.  So a lexical mapping 
> > is never 'incorrect' if it captures some sort of lexical 
> > similarity between labels, even if there is no semantic 
> > mapping between the corresponding concepts. 
> We used edit distance measures, so taking this approach 
> "fountains" and
> "mountains" are as close as "corpse" and "corpses". I was 
> thinking of the
> first one as being "incorrect" whereas the second one is "correct".
> Now conceptually you are right that they are both correct 
> lexical mappings.
> So maybe what I am actually doing is generating lexical 
> mappings, then human
> reviewing them to turn them into semantic mappings, only the 
> change from
> lexical mappings to semantic mapping is not explicit (because 
> I don't fancy
> doing lots of retyping by change the property names in the N3!)
> This is a pragmatic approach for now - longer term, I think 
> SIMILE intends
> to develop tools to do this type of task, so then it might be 
> possible to
> change the properties so they actually reflect when a mapping 
> relation is
> changed from being just a lexical mapping to a semantic mapping.
> > Could you possibly provide me with a list 
> > of all the types of useful lexical mapping you 
> > can think of?  
> No, sorry. I guess people like the WordNet and Cyc 
> communities have thought
> about this, and you may be more familiar with this work than I am?
> best regards
> Dr Mark H. Butler
> Research Scientist, HP Labs Bristol
> http://www-uk.hpl.hp.com/people/marbut 
Received on Wednesday, 9 June 2004 13:18:18 UTC

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