- From: Jacco van Ossenbruggen <Jacco.van.Ossenbruggen@cwi.nl>
- Date: Mon, 25 Jul 2005 17:03:11 +0200
- To: "Booth, David (HP Software - Boston)" <dbooth@hp.com>
- CC: public-swbp-wg@w3.org
Booth, David (HP Software - Boston) wrote: >Given the thunderous silence I've heard in response to my >thing-described-by.org proposal > I've been silent because I was still making up my mind :-) I like the possibility to distinguish between a physical thing and an associated information resource. A standard way to generate a URI for the former given the URI of the latter feels as a useful part, but still, only a part of complete solution that can be worked into a best practice guideline. Being able to specify the relation between the two URIs is another (again, the rdf:definedBy approach feels as only part of the solution). Questions I was asking myself about your thing-described-by.org proposal include: - If you want to change the URI of your homepage, do you also want to change the URI of yourself? If not, the dereferencing gives you the "wrong" document. So what do you do? - What if you use an HTML home page as the target URI in the thing-described-by.org (as you do now) and want to change that to an RDF file (e.g. at some point in the future you want to use your RDF/FOAF profile instead)? - what if you want both the HTML and RDF option? - what if you do not control the URI of the physical thing? - etc... Or more general: it feels a bit like the "wrong" way to do things: you define something "important"(the URI for yourself, a thing in the physical world) in terms of something "less important" (some digital artifact or information resource that is likely to change, even if you would use things like purl.org etc)[1]. In connection to the multimedia task force: A similar problem occurs in multimedia annotation. Since the multimedia resource being described almost always represents something in the physical world, one wants to distinguish meta data about the multimedia resource (e.g. #rembrandtPainting dc:format 'image/jpeg') from meta data about the physical work (#rembrandtPainting dc:format 'oil on canvas'). Standards like the VRA Core 3.0 [2] address this by defining in the meta data record [3] whether the record is about the "work" itself or the "image", or digital artefact that represents the work. Note that - AFAIK, VRA is also not defining the relationship between a "work" record and its "image" records - the painting itself may also represent things, so if your want to say something about the content of the painting, you might need another abstraction layer - in the context of describing visual physical resources (e.g. paintings) a single work typically has multiple digital images that "represent" the work. In general, it is often the other way around: a digital image may depict many things in the physical world (cf foaf:depicts vs foaf:img). - rdfs:label is a common property for relating an abstract resource with a short literal text that can be used (for instance in a UI) to represent a resource, but we do not have a similar common property for non-textual media. So if I want to tell my UI to show a thumbnail iso the literal given by rdfs:label, I need to define my own, non-standard property to do that. Idem for audio or video etc. Comments welcome (and David, I'm sorry if this is a distraction from the discussion you want to provoke) Jacco [1] Could be me just being old fashioned: I just need to understand that all the real things around me are defined by their digital counterparts, but I'm not there yet :-) [2] http://www.vraweb.org/vracore3.htm [3] not sure how to translate the concept of a Dublin Core or VRA Core "record" to RDF... Reification might not be the best way to do it. Maybe named graphs are an option ...
Received on Monday, 25 July 2005 15:03:18 UTC