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Re: (Round 2) Proposed Extensions to OWL

From: Frank Manola <fmanola@mitre.org>
Date: Sat, 28 Jun 2003 09:22:06 -0400
Message-ID: <3EFD967E.8000107@mitre.org>
To: "Roger L. Costello" <costello@mitre.org>
CC: tpassin@comcast.net, www-rdf-interest@w3.org

Could I suggest a look at 
http://ksl-web.stanford.edu/knowledge-sharing/papers/engmath.html?

--Frank

Roger L. Costello wrote:

> 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
>>
> 


-- 
Frank Manola                   The MITRE Corporation
202 Burlington Road, MS A345   Bedford, MA 01730-1420
mailto:fmanola@mitre.org       voice: 781-271-8147   FAX: 781-271-875
Received on Saturday, 28 June 2003 08:58:41 GMT

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