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Re: Context-Sensitive Semantic Relations

From: Antoine Isaac <aisaac@few.vu.nl>
Date: Sun, 24 Feb 2013 17:50:46 +0100
Message-ID: <512A44E6.6010004@few.vu.nl>
To: <public-esw-thes@w3.org>
Dear Cameron,

This is a very interesting case, but bear in mind that SKOS was developed to be 'simple' so it won't solve such an issue out-of-the box!

First allow me to put transitivity out of the discussion. From what you describe, it seems your first requirement is to contextualized one simple "broader" statement. If in the context of philosophy of physics you find that ex:quantumPhysics has ex:consciousness as a broader concept, then you're screwed, independently on whether the simple "broader" link allows you to get transitivity or not!

In fact your case seems to fall in the 'information containment' requirements, as we alluded to at
http://www.w3.org/TR/2009/NOTE-skos-primer-20090818/#secskoscontainment

As you can see, a solution proposed there would be indeed to create several concept schemes, e.g. ex:philosophyOfMindCS and ex:philosophyOfPhysicsCS. Since concept scheme can share concepts, you may state:

ex:quantumPhysics skos:inScheme ex:philosophyOfMindCS .
ex:consciousness skos:inScheme ex:philosophyOfMindCS .
ex:quantumPhysics skos:inScheme ex:philosophyOfPhysicsCS .
ex:consciousness skos:inScheme ex:philosophyOfPhysicsCS .
ex:philosophyOfMindCS { ex:quantumPhysics skos:broader ex:consciousness . }

This would make the broader statement specific to one named graph, and thus not accessible from other contexts. It is only when explicitly querying for data in ex:philosophyOfMindCS that the skos:broader statement would be valid.
The drawback of this is that it forces to use named graphs, which are still being worked on in the next RDF version.

One alternative, which you have already thought of, is to create a specialization of skos:broader for the "contexts" you're interested in, and not to have "duplication" of concept schemes (and named graphs). You could have
ex:philosophyOfMindBroader rdfs:subPropertyOf skos:broader .
ex:philosophyOfPhysicsBroader rdfs:subPropertyOf skos:broader .
And just use the property with the good context to make your statement:
ex:quantumPhysics ex:philosophyOfMindBroader ex:consciousness .

The problem with this solution is that it will scale very badly if you have many contexts.

I hope this helps,

Antoine



> Dear SKOScommunity,
>
> I would appreciate advice on a question about extending SKOS' functionality. I work with the InPhO Project (http://inpho.cogs.indiana.edu <http://inpho.cogs.indiana.edu/>), and we are currently considering a transition to SKOS. We are particularly attracted to the fact that the SKOS:broader relation allows one to be agnostic about transitivities. However, we would really like to infer *some* transitivities--but only ones that are context specific. Let me explain.
>
> A primary component of our knowledge base is a taxonomy of philosophical ideas, developed and populated by a combination of statistical measures on a corpus of digitized text and expert feedback. Most basically, we use an informational J-measure to decide when two ideas are related, and an entropy-based measure to decide when one idea is more general than another. This allows us to build and populate a taxonomy of philosophical ideas, organized by their semantic relevance.
>
> What is really desired is a transitive skos:broader relation, but one that holds only in certain contexts. For example, it may be the case that /quantum physics/ is a more specific topic than /consciousness/, but only in the context of /philosophy of mind/. In the context of /philosophy of physics/--where /quantum physics/ is discussed in many contexts independently of /consciousness/--the reverse may be true.
>
> Most generally, the right model is one of overlapping semantic fields in multi-dimensional semantic space. More general topics have more "volume" than more specific ones, and can contain those of terms they are broader than. This semantic space can be truncated by restricting one's attention to a particular sub-region. For example, if one restricted one's search to philosophy of mind, then we would chop off all areas of terms' semantic spaces that fall outside that region. This might change the containment relations of terms remaining in that space. Inside the semantic space of /philosophy of mind/, the space for /quantum physics/ might be contained inside the remaining space for /consciousness/, but this is only because most of the region of /quantum physics/ has been "chopped off" by restricting one's attention. I suspect that, in reality, most taxonomic semantic relationships are context-sensitive in this way.
>
> The question then remains how to best model such a context-sensitive containment relation. I see a few different approaches in SKOS, none of which are ideal. Perhaps most simply, one could treat each context of interest as a separate conceptScheme. But this would be rather ad hoc and lacks generality. Alternatively, one could try to create a specialized suproperty of skos:broader, e.g. skos:broaderThanContextSensitive. But then one would need a way to independently specify the context in which the relation held, and within which transitivites could be inferred. This would seem to be a metamodeling task, requiring a triple about another triple.
>
> Have others already considered similar complexities? Any advice would be greatly appreciated. (Apologies if I've missed a relevant prior discussion in the archive!)
>
> Best Wishes,
>
> Cameron Buckner
> University of Houston
> Department of Philosophy
> 713.743.2255
>
> Alexander von Humboldt Postdoctoral Fellow
> Institut für Philosophie II*
> *Ruhr-Universität, Bochum
>
> http://cameronbuckner.net/professional/
Received on Sunday, 24 February 2013 16:51:20 UTC

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