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Re: (Round 2) Proposed Extensions to OWL

From: Richard H. McCullough <rhm@cdepot.net>
Date: Thu, 3 Jul 2003 08:30:49 -0700
Message-ID: <000201c3417b$6ab11980$be7ba8c0@rhm8200>
To: "NJ Rogers, Learning and Research Technology" <Nikki.Rogers@bristol.ac.uk>, "Thomas B. Passin" <tpassin@comcast.net>, "www-rdf-interest" <www-rdf-interest@w3.org>
Cc: "Costello,Roger L." <costello@mitre.org>, "jon" <jon@spin.ie>, "Apollo, Adrian" <Thinkonaut@aol.com>

I think it's time to step back & consider the OWL ontology in a broader
context.

1. measurements
People identify attributes like "length" by comparing a number of things
which have length.
People measure the value of "length" by using one of the things as a
"standard".
In general terms (a la MKR)
    measurement := man do measure od thing with standard done;

2. methods
People define general methods like "measure length" and "compare length".
Using Roger's recent example (a la MKR)
    6300 := Roger L. Costello do measure length od Yangtze River
                                    with standard = kilometer
                                    done;
    3914 := Roger L. Costello do measure length od Yangtze River
                                    with standard = mile
                                    done;
    Yangtze River has
            LengthInKilometers = 6300,
            LengthInMiles = 3914;
    LengthInKilometers, LengthInMiles  subClassOf  LengthMeasure;
    equivalent := Roger L. Costello do compare length od 6300, 3914 done;

(I assume that the definition of "compare length" includes measurement
"types" and "precisions".)

3. OWL ontology
Obviously, we want to be able to replace "Roger L. Costello" by an automated
agent where possible.
But that replacement does not change the fundamental ideas of "measurements"
and "methods".
OWL can handle different types of measurements with no difficulty, but I
think OWL needs a new
mechanism to handle methods/commands/actions.

Dick McCullough
knowledge := man do identify od existent done;
knowledge haspart proposition list;

----- Original Message ----- 
From: "NJ Rogers, Learning and Research Technology"
<Nikki.Rogers@bristol.ac.uk>
To: "Thomas B. Passin" <tpassin@comcast.net>; "www-rdf-interest"
<www-rdf-interest@w3.org>
Cc: "Costello,Roger L." <costello@mitre.org>; "jon" <jon@spin.ie>
Sent: Thursday, July 03, 2003 3:42 AM
Subject: Re: (Round 2) Proposed Extensions to OWL


>
> > That is why I prefer to use an abstract Tranformation thing that could
be
> > specialized for one to one length comparisons, for example.  Better not
to
> > have to remodel when we hit other cases, within reason of course.
> >
>
> I have been watching this discussion with interest and I think the above
is
> an important point.
>
> I'm not certain I have a point here, but it is good to bounce back and
> forth from what we "KNOW" and what we "WANT" in a problem solving debate
> like this.
>
> [KNOW] I'm no expert in this field but I think that at the moment one can
> express equivalence in owl only for comparing RDF triples.
>
> [WANT] I think we need: a way of expressing equivalence between more
> complex graph structures than simple triples and also for similarly
> entailing equivalent graph structures.
>
> (diagramatically this is:
>
> resource#1 --> length --> resource#X --> value --> 2.5
>              --> unit_of_measure --> cm
>
> - ontologies answer questions for "is cm the same as centimetre?"
>
> resource#2 --> length --> resource#Y --> value --> 1
>              --> unit_of_measure --> inch
>
> and we want to express that these graphs are equivalent for our
application
> that should happen to care,
> so we could lose one modelling - inches, say - and have no material loss
of
> information if our application was to be using metric, say.
>
> Also, that we can entail one from another means we need a transformation
> mechanism i.e. one that can generate the necessary triples for
> inches-compatible applications, from the cm-based triples.
>
> The transformation is of the portion of the graph that extends from
> resource#X or resource#Y and is applied via a rule that says somthing
> like:if you want to entail triples that have inch instead of cm then you
> have to
> 1. inspect the unit_of_measure's value
> 2. find it's transform operation re the unit_of_measure you require (ie
> apply a "divide by 2.5" mathematical operation) - and this could be
> expressed in the rdf/xml in ways discussed in this thread
> 3. find the value to which to apply this transform operation (ie the
> literal value of the 'value' property above).
>
> It is up to the application to do the mathematical processing for the
> conversions - perhaps rdf api's have/will get this built in? - but the
> important bit is to be able to express equivalence/entailment over
> something more complex than binary graph structures - and p'haps owl is
the
> place to do this, I don't know.
>
> ie Note here: multiply *what* by 1.609344 - with a view to a generic
> approach to these types of problems you can't lose that bit of the graph:
>
> <owl:Class rdf:ID="MilesLength">
> <con:conversion>
> <con:ConversionFunction>
> <con:origin rdf:resource="#MilesLength"/>
> <con:target rdf:resource="#KilometerLength"/>
> <con:transform>{something meaning multiply by 1.609344}</con:transform>
> </con:ConversionFunction>
> </con:conversion>
> <owl:Class>
>
>
> Nikki
>
> ----------------------
> NJ Rogers, Technical Researcher
> (Semantic Web Applications Developer)
> Institute for Learning and Research Technology (ILRT)
> Email:nikki.rogers@bristol.ac.uk
> Tel: +44(0)117 9287096 (Direct)
> Tel: +44(0)117 9287193 (Office)
>
>
Received on Thursday, 3 July 2003 11:54:47 GMT

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