Side question : mapping OWL classes to SKOS concepts Re: SKOS Guide and owl:sameAs

Mark

I made a quick answer to Nabohita before reading yours which is way more 
accurate. Sorry for the noise.

Of course I agree with whatever you write below,  but there is a side 
and still open issue, on which I'm currently dealing internally. How do 
you map (a hierarchy of) classes in an RDFS/OWL ontology to (a hierarchy 
of) SKOS concepts. The rationale of that is that you can model the same 
domain using some OWL ontology for a knowledge base application, and 
using a SKOS taxonomy (so-called) for indexing-retrieval-navigation 
purposes. For example in a Tourism agency back-office ontology, I have a 
"Hotel" class  with subclasses "OneStar" to "FiveStar",  but in the 
end-user Web interface I have this simple hierarchy of (SKOS) concepts.

Accomodation
    Cheap_Accomodation
    Standard_Accomodation
    Luxury_Accomodation

In the back office ontology, "Hotel du Parc" is an instance of the (OWL) 
class "ThreeStar", with an attached description (document). In the 
end-user interface, the description is indexed by the concept "Standard 
Accomodation". I would like to express in a mapping that any instance of 
"ThreeStar" in the back-office ontology will result in an indexation of 
its description by the concept "Standard Accomodation" in the end-user 
navigation. Waht is needed here is a one-way mapping from a OWL class 
hierarchy to a SKOS concept hierarchy. The SKOS concept hierarchy is 
here a sort of "simplified view" of the OWL class hierarchy.

Seems to me this will be a frequent use case if both OWL ontologies and 
SKOS concept schemes are used in integrated environments. And there is 
no provision, AFAIK, neither from OWL side, nor from SKOS side, for the 
expression of such a mapping. Of course I can use a plain "rdfs:seeAlso"

a:ThreeStar      rdfs:seeAlso      b:Standard_Accomodation

But this is too weak semantics for the purpose at hand.

Since we need that right now for Mondeca applications, we are developing 
our own vocabulary for it, but of course would be happy to see this 
issue put on the standardisation track.

Bernard

Mark van Assem a écrit :
> Hi,
>
> There is a confusion of different things here.
>
> 1- skos:Concept is a class.
> 2- instances of skos:Concept are called "concepts" in the SKOS documents.
>
> 3- mapping of skos:Concept to another class can be done with 
> owl:equivalentClass
> 4- mapping of instances of skos:Concept to other skos:Concept 
> instances (from other vocabularies) can be done with owl:sameAs
> 5- mapping of instances of skos:Concept to other instances (from other 
> vocabularies) can also be done with the SKOS mapping properties, e.g. 
> exactMatch [1]
>
> Now the confusion is about which kind of mapping (3-5) is meant. The 
> "Concept Identity and Mapping" section [2] states that mapping type 4 
> should not be used, instead type 5 is better. This is because the 
> former states that they are the same *in every respect*, while the 
> latter only states that their extensions are the same (set of docs 
> indexed with one concept is also properly indexed with the other). If 
> you use the former you also merge their metadata, e.g. date of 
> creation and scheme they belong to. They become indistinguishable. The 
> latter keeps them distinguishable.
>
> The text mentioned does not refer to type 3 at all. This mapping would 
> be required if someone is not using the SKOS schema for a vocabulary, 
> but  something similar. Then a mapping
>
>     skos:Concept owl:equivalentClass my:Concept
>
> can be used to make all instances of my:Concept also skos:Concepts, so 
> they can be manipulated by software that understands SKOS.
>
> Hope this helps,
> Mark.
>
> [1]http://www.w3.org/2004/02/skos/mapping/spec/#exactMatch
> [2]http://www.w3.org/TR/2005/WD-swbp-skos-core-guide-20051102/#secidentity 
>
>
> Nabonita Guha wrote:
>> */Bernard Vatant <bernard.vatant@mondeca.com>/* wrote:
>>
>>  >A skos:Concept is not a class, and the domain of 
>> owl:equivalentClass is
>>  >owl:Class
>>
>> Whereas in SKOS Core guide 
>> (http://www.w3.org/TR/2005/WD-swbp-skos-core-guide-20051102/#secconcept), 
>> skos:Concept has been described as a class. If it's not a Class then 
>> what it can be considered as?
>>
>> Best,
>>
>> Nabonita Guha
>>
>> Senior Research Fellow
>> Documentation Research & Training Centre
>> Indian Statistical Institute
>> Bangalore INDIA
>>
>>
>>
>>
>>
>>     Hi Andrew
>>      > The SKOS guide [1], in the "Concept Identity and Mapping"
>>     section, states that owl:sameAs *should not* be used to indicate
>>     that two concepts share the same meaning. It gives some rationale in
>>     the section for this. Looking at the OWL guide [2], in the "4.1.
>>     Equivalence between Classes and Properties" section, I'm wondering
>>     whether one can use owl:equivalentClass to indicate that two
>>     concepts share the same meaning. If there is a reason why
>>     owl:equivalentClass can/cannot be used for this, should it also be
>>     mentioned in "Concept Identity and Mapping" section?
>>      >
>>     Yes, there is a good reason.
>>     A skos:Concept is not a class, and the domain of 
>> owl:equivalentClass is
>>     owl:Class
>>
>>     Cheers
>>
>>     Bernard
>>
>>      >
>>      > Thanks, Andy.
>>      >
>>      > [1]
>>      > [2]
>>      >
>>      >
>>      >
>>
>>     --
>>     *Bernard Vatant
>>     *Knowledge Engineering
>>     ----------------------------------------------------
>>     *Mondeca**
>>     *3, cité Nollez 75018 Paris France
>>     Web: www.mondeca.com
>>     ----------------------------------------------------
>>     Tel: +33 (0) 871 488 459
>>     Mail: bernard.vatant@mondeca.com
>>     Blog: Leçons de Choses
>>
>>
>>
>> ------------------------------------------------------------------------
>> Want to start your own business? Learn how on Yahoo! Small Business. 
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>>
>

-- 

*Bernard Vatant
*Knowledge Engineering
----------------------------------------------------
*Mondeca**
*3, cité Nollez 75018 Paris France
Web:    www.mondeca.com <http://www.mondeca.com>
----------------------------------------------------
Tel:       +33 (0) 871 488 459
Mail:     bernard.vatant@mondeca.com <mailto:bernard.vatant@mondeca.com>
Blog:    Leçons de Choses <http://mondeca.wordpress.com/>

Received on Thursday, 2 November 2006 09:26:15 UTC