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Re: Species Concept Mapping RDF fixes and question, should the species be ?represented as a class? Class SpeciesConcept => Class Species Cougar

From: Antoine Isaac <aisaac@few.vu.nl>
Date: Sat, 05 Dec 2009 11:49:01 +0100
Message-ID: <4B1A3A9D.1010203@few.vu.nl>
To: Richard Cyganiak <richard.cyganiak@deri.org>
CC: Peter DeVries <pete.devries@gmail.com>, public-lod@w3.org, dmozzherin@gmail.com
Hi Richard,

> So, can an rdfs:Class also be used as a skos:Concept, or vice versa?


> OWL DL folks will obviously not like this, but that's not my problem.
> A problem might be this: If there is a skos:Concept, and we use it as a 
> class, what exactly are the instances of that class? Having this:
>    foo:Cougar a skos:Concept; skos:prefLabel "Cougar".
> And then doing this:
>    bar:Bob a foo:Cougar .
> Then Bob could be an animal, or Bob could be some sort of document, 
> because the foo:Cougar concept may have been a "container" for documents 
> rather than animals. So the "bar:Bob a foo:Cougar" triple really just 
> tells us that bar:Bob is somehow related to or about cougars, but not 
> that Bob is an animal of the species Cougar. This problem could be 
> solved by saying that "foo:Cougar rdfs:subClassOf ex:Animal". So the 
> problem can be worked around. But it still shows that using concepts as 
> classes is tricky business.

I never pretended that was easy, just that there were fewer problems ;-)

However, I would in general expect that the link between a document and its subject should be represented by a dedicated property that is not rdf:type [1].
If people generally adopted this pattern, there would be less chance of someone's using the cougar concept as the class of documents about cougars, which I expect is the most likely confusion.

But of course you can never remove all danger. When you start using a concept as a class, I guess it would be good practice to add some documentation (e.g. an rdfs:comment on the class) to clarify your intention.

As you say in the following, one can expect less issues for the other direction. All (RDFS/OWL) ontologies can be regarded as knowledge organization systems, but KOSs are generally not trivially mapped into ontologies.

> The other way round -- using classes as concepts -- seems safer. I find 
> it hard to find a practical problem with this. Both for classes and for 
> concepts there are custom properties for indicating equivalence -- 
> owl:equivalentClass and the different skos:match properties -- so one 
> can steer clear of owl:sameAs and avoid most of the usual coreference 
> problems.



[1] http://www.w3.org/TR/skos-primer/#secindexing

> On 3 Dec 2009, at 18:58, Antoine Isaac wrote:
>>>> And in fact, while I understand that it is not very intuitive to 
>>>> have Bob the cougar as a skos:Concept (even though it is technically 
>>>> allowed), I see less problems for dealing this way with the class of 
>>>> cougars...
>>> Mentioning that you see less problems without going into any detail 
>>> is not exactly useful. I see more problems.
>> Yes, I should have been clearer.
>> In fact the most important argument (as I understand it from the 
>> discussion you started at [1]) against considering a given entity as a 
>> skos:Concept is that this entity may not have been designed as part as 
>> a knowledge organization endeavour. It is for example rather 
>> far-stretched to say that a person like Michelle Obama was conceived 
>> as part of a knowledge organization system.
>> My point is that this is less problematic for classes, as these are 
>> items of a knowledge organization system from the start. They are also 
>> "taxonomist business objects", aren't they? So we could easily treat 
>> them as skos:Concepts.
>> We have in fact touched this aspect in some parts of the SKOS 
>> documentation [2,3,4]. I'd be very interested to know whether you 
>> think this is wrong view!
>> Best,
>> Antoine
>> [1] http://lists.w3.org/Archives/Public/public-esw-thes/2009Nov/0000.html
>> [2] http://www.w3.org/TR/2009/NOTE-skos-primer-20090818/#secskosowl
>> [3] http://www.w3.org/TR/skos-reference/#L896
>> [4] http://www.w3.org/TR/skos-reference/#L1170
>>>> Best,
>>>> Antoine
>>>>> 2. I'm not sure if it's wise to use the same URI for the Cougar 
>>>>> "concept" and the Cougar "class". I don't think that this "punning" 
>>>>> is against any spec, but it will cause endless head-scratching 
>>>>> among potential users of your data. It would be more 
>>>>> straightforward to mint a separate URI for the class, and relating 
>>>>> it 1:1 to the species concept using an appropriate property 
>>>>> (there's probably one in UMBEL; if not, mint your own -- maybe 
>>>>> "speciesClass"). Since you own the URI space anyway, minting new 
>>>>> URIs would be cheap.
>>>>> This kind of punning between concepts, things and classes is an 
>>>>> interesting issue, and I'm afraid that it's not yet well 
>>>>> understood. Avoiding it puts you on the safe side.
>>>>> That being said, can you talk a bit about your motivation for 
>>>>> wanting to re-use the same URI?
>>>>> Best,
>>>>> Richard
>>>>>> This should work with OWL2 but I don't know how well it will work 
>>>>>> with the
>>>>>> LOD.
>>>>>> Also I created a VERY preliminary OWL document that would contain 
>>>>>> a much
>>>>>> more complete representation of the species.
>>>>>> My thoughts are that these OWL documents would be used to help 
>>>>>> determine
>>>>>> what specimens are instances of what species concept.
>>>>>> The goal would be to provide an OWL document for those who need a 
>>>>>> more
>>>>>> complete description of what we mean by the URI, while
>>>>>> also providing a much lighter RDF representation that could be 
>>>>>> used for
>>>>>> concept mapping etc.
>>>>>> However, I don't know if I am going about this in the right way.
>>>>>> Below are my VERY preliminary examples of what these OWL documents 
>>>>>> might
>>>>>> look like.
>>>>>> The example has some attributes that I thought should be included 
>>>>>> in a
>>>>>> species document, but it does not have everything that would like to
>>>>>> eventually include.
>>>>>> http://rdf.taxonconcept.org/owlses/v6n7p/2009-12-01.owl
>>>>>> Doc's at http://rdf.taxonconcept.org/owlses/v6n7p/owl_doc/index.html
>>>>>> The common classes etc, would eventually be moved to a separate 
>>>>>> ontology
>>>>>> that would be imported into each individual species ontology.
>>>>>> And these ontologies will need to be fixed so that they work 
>>>>>> together, I
>>>>>> don't think they do right now.
>>>>>> Thanks in Advance, :-)
>>>>>> - Pete
>>>>>> ----------------------------------------------------------------
>>>>>> Pete DeVries
>>>>>> Department of Entomology
>>>>>> University of Wisconsin - Madison
>>>>>> 445 Russell Laboratories
>>>>>> 1630 Linden Drive
>>>>>> Madison, WI 53706
>>>>>> GeoSpecies Knowledge Base
>>>>>> About the GeoSpecies Knowledge Base
>>>>>> ------------------------------------------------------------
Received on Saturday, 5 December 2009 10:49:39 UTC

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