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Re: How to do it/Tricks of the trade for closed world reasoning

From: Jeff Heflin <heflin@cse.lehigh.edu>
Date: Fri, 30 Aug 2002 17:55:13 -0400
Message-ID: <3D6FE9C1.D6F7E682@cse.lehigh.edu>
To: Deborah McGuinness <dlm@ksl.stanford.edu>, webont <www-webont-wg@w3.org>

Whoops, here's the footnote:

[1} http://www.cse.lehigh.edu/~heflin/pubs/#aaai-02

Jeff Heflin wrote:
> 
> Deborah,
> 
> I've also done some work on a different kind of closed world
> information.
> In a paper [1] I presented at the recent AAAI Ontologies for the
> Semantic Web workshop, I discussed how Oren, Etzioni, and Weld's local
> closed world (LCW) information (also called local completeness
> information) could be expressed in DAML+OIL. Such information
> essentially allows you to say that a particular document has complete
> information on the members of some class (for example, American
> Airline's website has complete information on all flights by American
> Airlines). Although I introduced new syntax to do this, I showed how it
> could also be represented using existing DAML+OIL syntax (the key of
> course is to use oneOf to enumerate all the instances) and then same
> that this is the sameClassAs whatever class expression you want to say
> you have complete information for (note, although I didn't catch it
> before publishing the paper, the talk I gave at the workshop actually
> shows a simpler way to do this than the paper does).
> 
> Jeff
> 
> [1]
> Deborah McGuinness wrote:
> >
> > ACTION: Deb to take a shot at writing up the closed world example
> >
> > I wrote up a simple example of closed world reasoning in:
> >
> > http://www.ksl.stanford.edu/people/dlm/daml/closedWorld.html
> >
> > This just counts the number of values on a property on an individual and
> > asserts that maximum cardinality restriction on that property for the
> > individual.
> > This is the simplest notion of closed world reasoning that we can
> > capture.
> > I have done some other work (with borgida and hull) on attempting to
> > close off an entire individual
> > and put the work down a few years ago when it was more complicated than
> > we anticipated.
> > I will also add a summary of where we left off in a more complicated
> > example.
> >
> > i am enclosing the contents of the url above for archiving purposes for
> > the list.
> > I used a combination of Guus's how to do it style and my previous tricks
> > of the trade style.
> >
> > d
> >
> > ==========
> > OWL/DAML+OIL "Tricks of the Trade / How To Do It":
> > Closed World Reasoning Example
> > Author:  Deborah L. McGuinness
> >
> > --------------------------------------------------------------------------------
> >
> > Title - Closed World Reasoning.
> >
> > Task/Modeling problem - Include a notion of closed world reasoning in an
> > OWL or DAML+OIL knowledge base. There are many examples of closed world
> > reasoning but this example includes two common cases.
> > State that the known values for a particular property on a particular
> > individual are the only values for that property on that individual.
> > Assume for example, that there is an individual instance of the class
> > "Person" named "Deborah" with a property "hasCar" with a value
> > "Saab900Turbo". The task is to allow a reasoner to infer that Deborah
> > only has the saab (and no new distinct individuals will be added as
> > values to her hasCar property).
> > Observation - DAML+OIL and OWL do not make the closed world reasoning
> > assumption, i.e., they do not assume that information that is not known
> > to be true is false. They work with an "open world reasoning"
> > assumption, i.e., they assume that information that is currently not
> > known may become known in the future. Thus, just because Deborah only
> > has one known value for a hasCar property does not mean that she may not
> > have more cars. Said another way, there is no implicit maximum
> > cardinality restriction on Deborah's hasCar property.
> >
> > Abstracted solution -
> > Count the number of values for a property on an individual and then
> > assert a max cardinality on that property for that individual.
> >
> > Example solution - In this particular case, we would add a maximum
> > cardinality restriction of 1 on Deborah's hasCar property. This would
> > allow reasoners to infer that no additional distinct values for
> > Deborah's hasCar property may be added (without first removing the value
> > of Saab900Turbo).
> >
> > Notes -
> >
> > This solution is the same as the notion of closing a role in the CLASSIC
> > description logic. More issues on closing roles can be found in:
> > - Ronald J. Brachman , Deborah L. McGuinness , Peter F. Patel-Schneider
> > , Lori Alperin Resnick , and Alex Borgida. ``Living with CLASSIC: When
> > and How to Use a KL-ONE-Like Language,'' in John Sowa, ed., Principles
> > of Semantic Networks: Explorations in the representation of knowledge ,
> > Morgan-Kaufmann: San Mateo, California, 1991, pages 401--456.
> > http://www.ksl.stanford.edu/people/dlm/papers/living-with-classic-abstract.html
> >
> > -Alex Borgida, Rick Hull, Deborah McGuinness. On the Confluence of the
> > Closing Order in Description Logic Knowledge Bases. Working Draft.
> >
> > --
> >  Deborah L. McGuinness
> >  Knowledge Systems Laboratory
> >  Gates Computer Science Building, 2A Room 241
> >  Stanford University, Stanford, CA 94305-9020
> >  email: dlm@ksl.stanford.edu
> >  URL: http://ksl.stanford.edu/people/dlm/index.html
> >  (voice) 650 723 9770    (stanford fax) 650 725 5850   (computer fax)
> > 801 705 0941
Received on Friday, 30 August 2002 17:55:16 GMT

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