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Re: Performance issues with OWL Reasoners => subclass vs instance-of

From: Phillip Lord <phillip.lord@newcastle.ac.uk>
Date: Tue, 19 Sep 2006 14:42:03 +0100
To: Chimezie Ogbuji <ogbujic@bio.ri.ccf.org>
Cc: w3c semweb hcls <public-semweb-lifesci@w3.org>
Message-ID: <ueju83rdg.fsf@newcastle.ac.uk>

>>>>> "CO" == Chimezie Ogbuji <ogbujic@bio.ri.ccf.org> writes:

  >> Part of the problem with DL reasoners and their scalability is,
  >> indeed, their relative immaturity. But, part of the problem is
  >> because that is just the way that universe is built. Ain't much
  >> that can be done about this.

  CO> I disagree and my point is that the universe you speak of is
  CO> framed by a specific reasoning algorithm. 

No, it isn't. Part of the issues with scalability is that the
complexity of solving OWL is fairly high -- it's just a hard
problem. This is independent from the algorithm being used to solve
it. It's a guarentee of worst case time performance for any algorithm,
including those not developed. 

Again, this is not necessarily a problem. Almost all programming
languages have unbounded worst case complexity -- for a arbitary java
program you can never guarentee that it will complete. 


  >> Memory is not cheap if the requirements scale non-polynomially.
  >> Besides, what is the point of suggesting that large terminologies
  >> are not a problem? Why not try it, and report the results?

  CO> I plan to.  I simply don't think the assumption that Tableau
  CO> Calculus represents the known limitations of DL reasoning is a
  CO> very useful one.


I didn't say this. I am sure someone will come up with algorithms
which run quicker than at present. But there are fundamental
limitations there also. My current experience systems which reason
over OWL significantly faster tend to not be doing the same thing, but
something simpler. 

Phil
Received on Tuesday, 19 September 2006 14:16:40 GMT

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