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Re: Implementations of LCS for OWL

From: Chris Mungall <cjm@berkeleybop.org>
Date: Fri, 30 Apr 2010 09:26:30 -0700
Cc: Alan Rector <rector@cs.man.ac.uk>, Owl Dev <public-owl-dev@w3.org>, sonic@tcs.inf.tu-dresden.de
Message-Id: <BD685C5C-E214-493A-A19F-1F7C8A940FC6@berkeleybop.org>
To: Phillip Lord <phillip.lord@newcastle.ac.uk>

On Apr 30, 2010, at 1:31 AM, Phillip Lord wrote:

> Chris Mungall <cjm@berkeleybop.org> writes:
>> On Apr 29, 2010, at 4:08 AM, Alan Rector wrote:
>>> Or there's the least common named subsumer in the inferred
>>> classification lattice using lattice theoretical tools, but I  
>>> presume
>>> that is not what you are asking or you wouldn't be asking it.
>> Correct, it would be a solved problem if the result was drawn only
>> from the set of named classes.
> Okay, so email overlap.
> It seems reasonable to me to assume that at the time you want to
> calculate a semantic similarity, then you have all the three terms  
> that
> you want -- the two that you wish to compare, and the (unknown,
> explicitly expressed in the ontology) term that is the LCS.

With some knowledge bases that is a reasonable assumption; in other  
cases there may be a limited amount of pre-composition or the pre- 
composition may be fairly ad-hoc, and allowing class expressions in  
the LCS results will give you something more specific and informative.

> I can see a very strong use case why you might want to allow the query
> terms to not pre-exist, but why the LCS? What semantic similarity
> measures were you thinking of anyway? The information content based
> ones will, I think, require that the LCS pre-exist anyway.

I don't think that need be the case. Calculating the IC requires  
finding the cardinality of the extent of the LCS, and this can be done  
trivially using any OWL reasoner. Of course, there is a closed world  
assumption here but this is built into any IC calculation (the well  
known literature bias).

> Otherwise,
> you will have to test each LCS against the entire corpus for each  
> query.
> Phil
Received on Friday, 30 April 2010 16:27:04 UTC

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