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Re: [Dbpedia-discussion] Using DBpedia resources as skos:Concepts?

From: Antoine Isaac <aisaac@few.vu.nl>
Date: Thu, 05 Nov 2009 23:01:39 +0100
Message-ID: <4AF34B43.7010003@few.vu.nl>
To: Kingsley Idehen <kidehen@openlinksw.com>
CC: Neubert Joachim <J.Neubert@zbw.eu>, Simon Reinhardt <simon.reinhardt@koeln.de>, SKOS <public-esw-thes@w3.org>, Pat Hayes <phayes@ihmc.us>, dbpedia-discussion@lists.sourceforge.net

>>>> Sorry for causing some misunderstanding: My point was not that you 
>>>> SHOULD use skos:Concept. What I rather wanted to say is that it does 
>>>> no harm and that it's already in use for named entites.  This point 
>>>> arises from the suggestion to use skos:exactMatch/closeMatch. These 
>>>> properties are sub-sub-properties of skos:semanticRelation, which 
>>>> entails that subject and object of these properties are instances of 
>>>> skos:Concept (since skos:Concept are domain and range for 
>>>> skos:semanticRelation).
>>>> The great advantage of skos:exactMatch/closeMatch (over owl:sameAs) 
>>>> is that their semantic doesn't smush the resources with all their 
>>>> properties (like the administrative properties you mentioned).
>>> Joachim,
>>> What do you mean by "smush" are you referring to the union expansion 
>>> that results from combing data from all the data sources in the 
>>> owl:sameAs relation? I pose my question with the skos:exactMatch 
>>> description page URL [1] for context. I see Transitivity and 
>>> Symmetry, which are factors re. decision making by reasoners re: 
>>> union expansion based on participants in the relation. Note, by 
>>> "union expansion" I mean the union of all data associated with the 
>>> data items in the relation.
>>> Primarily, I just want clarification about "smushing",  relative to 
>>> the property definition exposed by the skos:exactMatch URI,  more 
>>> than anything else. Thus, far I've simply assumed that 
>>> skos:exactMatch and owl:sameAs have similar implementation mechanics 
>>> re. union expansion, 
>> Just to clarify it, in case the mails that came after have not done 
>> it: using skos:exactMatch should *not* lead to attributing to the two 
>> resouces that it relates the union of all data that is attached to them.
>> I don't understand why transitivity and symmetry alone would allow a 
>> reasoner to infer such "smushing/union expansion". Let's consider a 
>> ex:connectedByARoad property. I can perfectly make it transitive and 
>> symmetric, and yet all the towns that this property relates are not 
>> one and the same.
> Sure, but the relation you use is neither "owl:sameAs" nor 
> "skos:exactMatch". I think the subtle item here is that the property 
> labels do actually matter. ex:connectedByARoad in no way conveys 
> co-reference. 

Er, yes. My comment was havily influenced by your "which are factors re. decision making by reasoners". Labels are not such a factor, so I inferred you were only basing your claim on the formal semantic axioms.

> BTW - your analogy is basically similar to a Transitivity 
> example I put out re. SKOS and DBpedia a few weeks ago [1] :-)


> I think your other response re. Ms. Obama goes back to the Subject 
> Matter/Heading delineation which I believe is the overarching focal 
> point of of SKOS (classification by phenotype so to speak). Its about 
> concept schemes and the hierarchies that may exist within and across 
> schemes in different data spaces. Whereas, with "owl:sameAs" we are 
> dealing with similar issues, but the orientation feeds of a genotype, so 
> to speak.

As long as you're ok with the fact that there can be concepts/subject matters that are corresponding to persons (even though they would not be persons themselves), I'm ok...



>>>> ------------------------------------------------------------------------ 
>>>> *Von:* Simon Reinhardt [mailto:simon.reinhardt@koeln.de]
>>>> *Gesendet:* Do 05.11.2009 17:35
>>>> *An:* Neubert Joachim
>>>> *Cc:* Richard Cyganiak; dbpedia-discussion@lists.sourceforge.net; 
>>>> SKOS; Pat Hayes
>>>> *Betreff:* Re: AW: [Dbpedia-discussion] Using DBpedia resources as 
>>>> skos:Concepts?
>>>> Hi
>>>> Neubert Joachim wrote:
>>>> > In my eyes, it's completely ok to use skos:exactMatch or 
>>>> skos:closeMatch
>>>> > in a situation like this (I did it myself for the STW Thesaurus for
>>>> > Economics mapping to dbpedia).
>>>> > > Thesauri and classifications are not restricted to abstract 
>>>> concepts.
>>>> > Some thesauri deal explicitly with individual things, e.g. the widely
>>>> > used Getty "Thesaurus of Geographic Names" or "Union List of Artist
>>>> > Names". Other thesauri (like STW) have sections (or facets, as 
>>>> Leonard
>>>> > put it) on geografic names along with others containing "pure" 
>>>> concepts.
>>>> > SKOS, as I understand it, is intended to cover all this and to be 
>>>> used
>>>> > beyond strict class hierarchies or class/individual dichotomies.
>>>> While I agree that using real-world entities for classification is 
>>>> ok I don't think this means you have to declare them to be 
>>>> (skos:)concepts. The "has subject" relationship in FRBR [1] for 
>>>> example can link a work to a concept but also to places, people, 
>>>> events, other works, etc. So in this case you can use real-world 
>>>> entities to classify the work (to state what its subjects are) but 
>>>> that doesn't mean you declare all those entities to be conceptual.
>>>> So in my eyes there's still value in keeping (skos:)concepts and 
>>>> other things apart. Concepts to me are closer to classes than to 
>>>> individuals. And as Dan pointed out concepts have administrative 
>>>> data attached - they get created and changed etc. so they're 
>>>> basically units of organisation.
>>>> I'd therefore prefer using the UMBEL terms or something else for 
>>>> aligning real-world entities and concepts.
>>>> > By the way, some of the SKOS properties (especially the
>>>> > prefLabel/altLabel/hiddenLabel semantics) can be useful in a broad 
>>>> range
>>>> > of applications. Eg. dbpedia itself could be used as a great 
>>>> source for
>>>> > synonym candidates by mapping the resources to skos:Concept and the
>>>> > labels for dbpedia:redirect resources to skos:altLabel.
>>>> Yup, it has a lot of useful annotation terms. They are all declared 
>>>> to be annotation properties and deliberately don't have skos:Concept 
>>>> in their domain. So you can use them on anything which is great!
>>>> Regards,
>>>>   Simon
>>>> [1] http://archive.ifla.org/VII/s13/frbr/frbr_current5.htm#5.2 - 
>>>> scroll down to "5.2.3 Subject Relationships"
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Received on Thursday, 5 November 2009 22:02:12 UTC

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