Pete Johnston wrote:
> Ivan said:
>
>
>>I read the document from an RDF point of view, and my comment
>>is probably for clarification only (but it may be worth
>>either adding this to the document or having a separate,
>>explanatory document).
>>
>>- The document defines a rich representation. I tried to
>>translate a rich representation into RDF, and I am not sure
>>it is correct. What I came up with as an example (using
>>Turtle syntax) is:
>>
>>dc:blabla [
>> dcterms:format [
>> rdf:type ex:MediaType;
>> dc:label "image/jpeg";
>> ]
>> rdf:value "base64 encoded bytes of the image".
>> ].
>>
>>ie, the property using a rich representation refers to a
>>blank node that includes a reference to a media type and the
>>value.
>
>
> Yes, that is pretty much how I envisaged the rich representation notion
> being represented using RDF. Actually, given that (according to the
> DCAM) a single statement may provide multiple rich representations for a
> single value, I think there may be an additional node and arc involved.
> So if, say, I want to say that a book was authored by some entity
> represented by a JPEG and by a GIF, then I think in RDF, that would look
> something like (gulp):
>
> _:mybook
> a ex:Book ;
> dcterms:creator [
> rdfs:seeAlso [
> dcterms:format [
> rdf:type ex:MediaType ;
> rdfs:label "image/jpeg" ;
> ] ;
> rdf:value "base64 encoded bytes"^^xsd:base64Binary
>
> ] ;
> rdfs:seeAlso [
> dcterms:format [
> rdf:type ex:MediaType ;
> rdfs:label "image/png" ;
> ] ;
> rdf:value "base64 encoded bytes"^^xsd:base64Binary
>
> ]
> ]
> .
>
> (Probably with some question marks over whether we use
> rdfs:seeAlso/rdf:value or some other properties?)
>
I think to re-use as much as possible existing properties is a good
thing, so...
>
>>The ex:MediaType is defined, in [1], as a class, hence
>>the extra blank node. It is also not clear how one defined a
>>particular media type..
>
>
> Are their URIs for the IANA registered MIME types?
>
> I found http://www.w3.org/2001/tag/2002/01-uriMediaType-9 expressing the
> desirability of having some URIs, but I'm not sure whether any were
> assigned/are in widespread use.
Unfortunately, I do not know more. Maybe it is a question you may want
to ask on the SW Interest Group, somebody may know about one...
It may well be that DCI will have to define those. Having a set of URI-s
for Media types would be a great plus for the community...
Ivan
>
> Pete
>
> ---
> Pete Johnston
> Technical Researcher, Eduserv Foundation
> Web: http://www.eduserv.org.uk/foundation/people/petejohnston/
> Weblog: http://efoundations.typepad.com/efoundations/
> Email: [log in to unmask]
> Tel: +44 (0)1225 474323
--
Ivan Herman, W3C Semantic Web Activity Lead
URL: http://www.w3.org/People/Ivan/
PGP Key: http://www.cwi.nl/%7Eivan/AboutMe/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf
|