Re: [Fwd: RDF Issues]

Hi Chas,

thanks for the comments.

At 15:43 12/03/2003 +0100, Charles McCathieNevile wrote:

>This was originally sent privately to Brian McBride as accessibility 
>comments - just making sure people see it.
>
>cheers
>
>Chaals
>
>--
>Charles McCathieNevile             Fundacion Sidar
>http://www.sidar.org/
>
>-------- Original Message --------
>
>There are two issues. The first is the lack of a standardised
>"abouteachprefix" in RDF.

I've recorded this as a comment on the syntax doc:

   http://www.w3.org/2001/sw/RDFCore/20030123-issues/#chas-01

The WG will consider this comment and get back to you in due course.

Brian

>The second, and I think more serious, is that there
>is no defined way to talk about a view of a document, where those views are
>defined by using a URIRef for a particular MIME type.
>
>I have tried to lay them out below, but am not writing terribly clearly
>today, so i hope this is enough to go on with. It might be useful to try and
>talk about this some more tonight or tomorrow - I will be around. I thought
>it was better to send something sooner than the perfect version later.
>
>(and finally due to various process wierdness please note that this email is
>supposed to be from me as an invited expert to the WAI PF group, representing
>La Fundaciòn Sidar, as charles@w3.org)
>
>cheers
>
>Chaals
>
>Issue 1 - aboutEachPrefix
>
>"aboutEachPrefix" seems to be a particular instance of a class of things.
>There are many cases where people want to talk about a set of objects without
>having to enumerate the list:
>
>- things in a particular namespace (the original aboutEachPrefix case) are
>published by the owner of that namespace;
>
>- the infinite set of times within a particular range for one calendar fall
>within the range of a particular date in another calendar (think about how
>many nameable times on the 1st of Ramadan 1476AH fall on a particular day in
>the gregorian calendar, as measured in Paris)
>
>- the homepages of staff at an organisation represent people at that
>organisation - that list can be provided by a Web service at any given time,
>or it is possible to determine whether a given resource is in that set, but
>it cannot be enumerated cleanly in a static document.
>
>(EARL statements about resources of this type are an example of a use case in
>accessibility - for example that these have been tested and found to contain
>appropriate structure or be valid before they were published).
>
>I am told by Jeremy Carroll that this problem can be dealt with by Jena and
>modelled using OWL. The issue is why this is not something that a "basic" RDF
>processor should be able to deal with. In the aboutEachprefix case it was
>(theoretically) available in basic processors which did not implement other
>"optional" specifications.
>
>===
>
>Issue 2 - referring to a particular view of a resource
>
>According to the RDF Concepts document, a statement that
><http://www.example.org/foo#svgView(viewBox(0,200,1000,1000))> <foo:isLike>
><bar:something>
>
>refers to something which is defined in the version of
>http://www.example.org/foo that has an RDF MIME-type. So if there is nothing
>returned with that MIME-type then the statement doesn't have a defined
>subject.
>
>It seems you also can't rely on content negotiation to say something like
>
><http://www.example.org/foo#svgView(viewBox(0,200,1000,1000))>
><foo:viewableAs> <mime:image/svg+xml> .
>
><http://www.example.org/foo#svgView(viewBox(0,200,1000,1000))>
><foo:describedInHTML> <http://www.example.org/foo#someDesc> .
>
>An accessibility use case is describing particular views of documents under
>particular conditions - for example giving some information about what kinds
>of 'delivery context' can make sense of that part of a resource, or pointing
>to another resource which can be used to understand a resource which a person
>with a disability can't use directly. It is often important to talk about a
>part of a document, because some parts will be accesible to people and others
>won't, and they want to know which is which. In the presence of
>content-negotiation, statements will be about fragments of versions other
>than the RDF one.
>
>
>

Received on Tuesday, 25 March 2003 11:34:27 UTC