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RE: (Round 2) Proposed Extensions to OWL

From: Jon Hanna <jon@spin.ie>
Date: Wed, 2 Jul 2003 12:18:19 +0100
To: "Roger L. Costello" <costello@mitre.org>, <www-rdf-interest@w3.org>
Message-ID: <NDBBLCBLIMDOPKMOPHLHMEPDFEAA.jon@spin.ie>

> An excellent analysis Jon!  I believe that your conclusion is correct
> that another level of indirection (i.e., another nesting level) is
> required.
>
> At the moment I have just one comment (I am still working through your
> ideas on expressing conversions, as well as Tom's most recent
> comments).  Here is the form that your analysis produced:
>
> <River rdf:ID="Yangtze">
>     <length>
>         <Length>
>             <measurement>
>                 <LengthInMiles>
>                     <number>3914</number>
>                 </LengthInMiles>
>             </measurement>
>         </Length>
>     </length>
> </River>
>
> (I made a few small changes.  Let me know if they are not acceptable.)
>
> Here is an alternate form, which is inline with Tom's proposal:
>
> <River rdf:ID="Yangtze">
>     <length>
>         <Length>
>             <measurement>
>                 <LengthMeasure>
>                     <transform rdf:resource="LengthInMiles"/>
>                     <number>3914</number>
>                 </LengthMeasure>
>             </measurement>
>         </Length>
>     </length>
> </River>
>
> Which of these two forms is preferred?  Are there advantages of one over
> the other?  /Roger
>

Another way of serialising the first as RDF/XML would be:

<River rdf:ID="Yangtze">
    <length>
        <Length>
            <measurement>
                <LengthMeasure>
                    <rdf:type rdf:resource="LengthInMiles"/>
                    <number>3914</number>
                <LengthMeasure>
            </measurement>
        </Length>
    </length>
</River>

Doing this (and treating LengthInMiles as a subClass of LengthMeasure) shows
that the only real difference between the first and second example is that
the first uses rdf:type instead of transform and that the first allows the
fact that the resource is a LengthMeasure to be deduced from knowledge about
LengthInMiles and/or measurement (subClassOf and range relationships
respectively).

rdf:type is more "natural" RDF to my mind, means something to every RDF
application, and allows for more compact and generally more human-readable
RDF/XML. Unless there were a clear reason not to I would favour rdf:type.
Received on Wednesday, 2 July 2003 07:16:28 GMT

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