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RE: (Round 2) Proposed Extensions to OWL

From: Adam Saltiel <adam.saltiel@btinternet.com>
Date: Sat, 28 Jun 2003 12:55:51 +0100
To: <www-rdf-interest@w3.org>
Message-ID: <003201c33d6c$39bb3bc0$0200a8c0@p800xp>

For some reason my post didn't appear so am posting again. I apologize
if it appears twice:-

This seems right.
But isn't there also the need to express the conditional:
where the unitary unit of measure is type:length-in-inches {resource
     {type:length-measure}
     {value:
         transform:
		transform-type:multiply
		{
             {
                 type:length-in-inches}
                 number: 1
             }
		}
     }
 }

 {resource
     {type:length-measure}
     {value:
         transform:
		transform-type:multiply
		{
             {
                 type:length-in-cm}
                 number: 2.54
             }
		}
     }
 }

where the unitary unit of measure is type:length-in-cm {resource
     {type:length-measure}
     {value:
         transform:
		transform-type:divide
		{
             {
                 type:length-in-cm}
                 number: 1
             }
		}
     }
 }

 {resource
     {type:length-measure}
     {value:
         transform:
		transform-type:divide
		{
             {
                 type:length-in-inches}
                 number: 2.54
             }
		}
     }
 }

etc?
The crucial concept is the unitary unit of measure. But this might lead
to a look up table of definitions or some mechanism for negotiating
which of a subset of terms from a restricted lexicon are agreed on for
current purposes. Perhaps the only way out here would be to reference
such a resource externally. This would allow the definition of the
unitary term for a set of common measures and, therefore, their
relationship, but begs the question of a universal solution that would
cover any case.

Adam Saltiel

> -----Original Message-----
> From: www-rdf-interest-request@w3.org [mailto:www-rdf-interest-
> request@w3.org] On Behalf Of Roger L. Costello
> Sent: 28 June 2003 11:31
> To: tpassin@comcast.net; www-rdf-interest@w3.org
> Cc: Costello,Roger L.
> Subject: Re: (Round 2) Proposed Extensions to OWL
>
>
> Hi Folks,
>
> Yes, I agree with Jeremy - I like the ideas that Tom has put forward.
I
> also like the ideas that Jon put forward.  Very exciting ideas!
>
> Some questions:
>
> 1. I am not sure that "transform" is the right word.  Both anonymous
> resources are talking about length measures (in fact, the same length
> measure).  But one *expresses* the length measure in inches, while the
> other *expresses* the length measure in centimeters.  So, it's not a
> "transform" but rather an *expression*, i.e.,
>
> {resource
>     {type:length-measure}
>     {value:
>         expression-form:
>             {
>                 type:length-in-inches}
>                 number: 1
>             }
>     }
> }
>
> or perhaps:
>
> {resource
>     {type:length-measure}
>     {value:
>         lexical-form:
>             {
>                 type:length-in-inches}
>                 number: 1
>             }
>     }
> }
>
> 2. How would this be expressed in XML?  Would it be expressed like
this:
>
> <Length rdf:ID="length-in-inches">
>     <rdf:value>1.0</rdf:value>
> </Length>
>
> and
>
> <Length rdf:ID="length-in-centimeters">
>     <rdf:value>2.54</rdf:value>
> </Length>
>
> Thus, both are expressing a Length.  The first is an instance of the
> length in inches.  The second is an instance of the length in
> centimeters.
>
> Thoughts?  Great stuff!  /Roger
>
> Tom Passin wrote:
>
> > Here is what we know, it seems to me -
> >
> > 1) Both resources are length measures.
> > 2) The value of a length measure can be expressed numerically in
> different
> > units.
> >
> > (This is a scalar quantity.  A more complex quantity, like a vector
or
> > tensor, would have to be expressed as some structured value).
> >
> > We know a few other things, but they can be formulated in various
ways.
> > Here is one way.
> >
> > 3) The numerical value of a length measure may be obtained by
applying
> an
> > operator (or a transformation) to it.  That is, conceptually
> > length-in-inches = L1 * M, where L1 is the operator for getting the
> length
> > in inches, and M is the measure.
> >
> > 4) A measure may have any number of such operators or transforms,
one
> for
> > each different unit of measure.
> >
> > Here is a set of triples (minus namespaces) for your two resources
that
> > captures, I think, the essence of these points -
> >
> > {resource
> >     {type:length-measure}
> >     {value:
> >         transform:
> >             {
> >                 type:length-in-inches}
> >                 number: 1
> >             }
> >     }
> > }
> >
> > {resource
> >     {type:length-measure}
> >     {value:
> >         transform:
> >             {
> >                 type:length-in-cm}
> >                 number: 2.54
> >             }
> >     }
> > }
> >
> > I think that these are admirably simple, and I doubt that you can
> simplify
> > them any more without losing their essence.
> >
> > The resource type can obviously be stated in OWL as part of an
ontology,
> and
> > so can the transform type.  If we had a standard way to make math
> statements
> > with OWL, we could make an OWL statement that the two transforms
(inch
> and
> > cm) had some kind of "equivalentValueTo" relationship.
> >
> > This approach takes the matter of the relationship between length in
cm
> and
> > length in inches away from the individual resources and puts in onto
the
> > expression of the relationship between the transform types.  I think
> this is
> > very appropriate.
> >
> > The upshot is that you need to come up with some convention for
> expressing
> > the relationship between the transforms - or of testing for
equivalence
> -
> > and then everything else can be handled in OWL.
> >
> > Cheers,
> >
> > Tom P
Received on Saturday, 28 June 2003 07:55:52 GMT

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