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RE: OWL and real world

From: <david.celjuska@bt.com>
Date: Fri, 24 Sep 2004 15:58:28 +0100
Message-ID: <0881CE20A5962844A62D246EBB24148F09F8032C@i2km03-ukbr.domain1.systemhost.net>
To: <tammet@staff.ttu.ee>
Cc: <www-rdf-interest@w3.org>

Tanel,

> >So my qestion at the bottom is how we could handly this
> >kind of exceptions? Because we know that life is full of
> >exceptions. Some birds don't fly, same mammals lay eggs
> >(Platypus is only one of them and to have a special class just
> >for this pour guy...), and who knows and one can never be sure.
> >  
> >
> People have researched these kinds of things for decades.
> 
> Read some intro about "nonmonotonic logic", and then
> continue with "default logic", which is a fairly clean
> subfield of the former. 

This might sound like weird question but Am I right
then if I say  that exceptions as I mentioned them are out
of the scope of FOL and thus can not be modelated in formal
ontologies?

Could in theory exist a construct in OWL called let say
exception which would handle this? I know the problem
is probably passed down to the stage were we can see that
not even exceptions are great solution for this. But
probably if we could say:
    
      chicken
     /
Bird
     \ eagl
       ...

Birds canFly true
chicken typeOf Bird
chicken canFly no
eagl typeOf Bird

it would do the magic. Meaning we would say that all
birds can fly but when we define chicken we would say
chiken can not fly. This would mean that we would have
to bring child priority over parent. I know from
formal logic this is incossited becasue what I just said
can be written as:

lets A is set of even numbers
a is a memeber of A
a is odd number

I would be indeed interested to lear more about non-monotonic
logic and default logic. If you can suggest some resources to me
it would be excelent.

> Another approach is to use
> bayesian or fuzzy reasoning, but I'd suggest to check
> the default logic stuff first. There are, of course, several
> different approaches I did not mention.

Yes, fuzzy ontologies were mine first thought but I
think it might be a huge cannon for a little bird as
we say - overkiller.

> When looking through the material, keep in mind
> that the problem you posed is a one of the fundamental,
> hard problems of AI. No really good solutions have
> appered so far. IMHO it is unlikely that any
> simple and/or universal solutions could ever
> appear.  This does not mean that nothing can be done:
> just that all solutions are going to be complex,
> partial and domain-specific.

What can you say then about my ugly solution which I
suggested - Having it interpreted by application - the
only thing which I hate is that then I am moving semantic
from Ontology to application and Ontologies as such are
not designed for this.

Any links to domain-specific solutions?

Thank you tons,

David
Received on Friday, 24 September 2004 14:58:07 GMT

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