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>

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 PReceived on Saturday, 28 June 2003 07:55:52 UTC

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