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RE: Correct Owl representation

From: <Deepali.Khushraj@nokia.com>
Date: Fri, 26 Sep 2003 20:07:45 -0400
Message-ID: <DC504E9C3384054C8506D3E6BB01246001753707@bsebe001.americas.nokia.com>
To: <www-rdf-interest@w3.org>


I wonder if it has something to do with datatype properties in OWL being specified as functional. So if focal-length is defined to have datatype xsd:string, then using focal-length as xsd:normalizedString (or xsd:token) could be valid. Unless we explicitly specify this information the parser has no way to figure it out.

E.g.
<owl:DatatypeProperty rdf:ID="focal-length">
        <owl:equivalentProperty rdf:resource="#size"/>
        <rdfs:domain rdf:resource="#Lens"/>
        <rdfs:range rdf:resource="&xsd;#string"/>
</owl:DatatypeProperty>

<Lens>
   <focal-length rdfs:datatype="&xsd;normalizedString">75-300mm zoom</focal-length>
   <f-stop rdfs:datatype="&xsd;normalizedString">4.5-5.6</f-stop>
</Lens>

I am not sure if this is a valid thing to do.

Regards,
Deepali

*DISCLAIMER*: This is a wild guess.

-----Original Message-----
From: ext Benjamin Nowack [mailto:office@e-senses.de]
Sent: Friday, September 26, 2003 6:31 PM
To: Monika Solanki
Cc: www-rdf-interest
Subject: Re: Correct Owl representation



Monika Solanki (monika@dmu.ac.uk) schrieb am 26.09.2003:
>(...)
><Lens>
>    <focal-length>75-300mm zoom</focal-length>
>   <f-stop>4.5-5.6</f-stop>
></Lens>
>
>Would the above be incorrect representation in OWL ?
>
>Would it be correct to do it like this  
>
><Lens>
>    <focal-length rdf:datatype="&xsd;string">75-300mm zoom</focal-length>
>   <f-stop rdf:datatype="&xsd;string">4.5-5.6</f-stop>
></Lens>
>
>If this is correct, then what is the rationale behind specifying range 
>as "String" in defining the property ?

you are right. properties of individuals always need the additional
datatype when serialized as RDF/XML (section 6.1 of [1]). I think the 
reason is the "RDF/XML" format. You can define the range at the ontology 
level, but this is separate from the instance level as the rdf:datatype
attribute seems to be required if you want to write _typed_ literals
(section 2.9 of [2]). I'm not sure but this could be the reason for the
redundancy, just to make sure that rdf parsers don't handle the property
values as plain literals.

hope that helps..

regards,
benjamin

[1] http://www.w3.org/TR/owl-ref/
[2] http://www.w3.org/TR/rdf-syntax-grammar/

___________________________
benjamin nowack

am exerzierplatz 1
de-97072 wuerzburg
Received on Friday, 26 September 2003 20:08:38 GMT

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