- From: Raphaël Troncy <Raphael.Troncy@cwi.nl>
- Date: Mon, 26 Oct 2009 23:06:27 +0100
- To: Pierre-Antoine Champin <swlists-040405@champin.net>
- CC: Toby Inkster <tai@g5n.co.uk>, Semantic Web <semantic-web@w3.org>
Dear all, This is indeed an interesting discussion that reminds the presentation I did earlier this year at the Second Linked Data on the Web Workshop collocated with the WWW 2009 conference. Have a look at the slide 11 at http://www.slideshare.net/troncy/interlinking-multimedia-how-to-apply-linked-data-principles-to-multimedia-fragments-ldow09 which exactly summarizes the problem. Where should we stop for conneg-ing between two representations of a resource? Is conneg-ing between an rdf+xml and video/* a behavior we should accept or ban? Are an image and its ASCII version close enough to be content negotiated? Are an image and a transcoded version close enough to be content negotiated even if they do not share a single common bytes? We had a conversation with Tim Berners Lee during this workshop that pretty much agrees with what Toby just wrote below ... while I was arguing than nobody has formally defined what is the 'sameness' of two representations of a resource. The accessibility community has defined the notion of "equivalent" when the two representations both fulfill the same function or purpose upon presentation to the user, and in an accessibility context, it is fine to say that a text is another representation of an audio resource ... >> Perhaps: >> >> GET /images/example HTTP/1.1 >> Accept: image/png, image/jpeg, image/*;q=0.5 >> >> should return the JPEG, but: >> >> GET /images/example HTTP/1.1 >> Accept: application/rdf+xml >> >> should return a 303 See Other to a different URL (e.g. >> </data/images/example> or </images/example;about>) which would provide >> an RDF description of the image. > > Although I would tend to agree with Toby on this, I keep thinking both > options (303 or 200 for the RDF version) are valid. > > After all, the pixel matrix conveyed by the JPEG encoding is also a > *representation* of a more abstract resource that we call an image (the > same *image* could be represented by a slightly different matrix using > another encoding, another color scheme, another resolution...). > > So why would the JPEG representation be more *intrinsic* to the image > than the RDF representation. What if the RDF representation contained a > property > :hasPixelGrid 'A65E8F9B87X78964...' > ? > > This is hair splitting, but I think it is worth questionning the > distinction between informational and non informational resources. This > distinction is often taken for granted, and I think it is often not as > clear as it seems... I agree. And I would also point out to a question post on the TAG mailing list [1] before the summer which unfortunately hasn't received many answers. Best regards. Raphaël [1] http://lists.w3.org/Archives/Public/www-tag/2009Jun/0180.html -- Raphaël Troncy EURECOM, Multimedia Communications Department 2229, route des Crêtes, 06560 Sophia Antipolis, France. e-mail: raphael.troncy@eurecom.fr & raphael.troncy@gmail.com Tel: +33 (0)4 - 9300 8242 Fax: +33 (0)4 - 9000 8200 Web: http://www.eurecom.fr/~troncy/
Received on Monday, 26 October 2009 22:07:45 UTC