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

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Thu, 05 Nov 2009 16:21:57 -0500
Message-ID: <4AF341F5.3080406@openlinksw.com>
To: Antoine Isaac <aisaac@few.vu.nl>
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
Antoine Isaac wrote:
> Hi Kingsley,
>>> 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.  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.

Still looking for the right language, bottom line. What they do is clear 
to me, but I want to be able to communicate (outwards from this 
community) with clarity, esp. as our audience is growing rapidly etc..



> Antoine
>> but their use targets vary i.e. skos:exactMatch works better for 
>> Concept Schemes (where the world view assumes Named Entities e.g., 
>> "People" aren't Concepts) while owl:sameAs works better for Named 
>> Entities (people, places, and other typical real more things, so to 
>> speak).
>> Links:
>> 1. 
>> http://linkeddata.uriburner.com/about/html/http/www.w3.org/2004/02/skos/core%01exactMatch 
>> Kingsley
>>> [SNIP]
>>> ..
>>> Cheers, Joachim
>>> ------------------------------------------------------------------------ 
>>> *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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Kingsley Idehen	      Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software     Web: http://www.openlinksw.com
Received on Thursday, 5 November 2009 21:22:45 UTC

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