- From: Stefan Decker <stefan@DB.Stanford.EDU>
- Date: Wed, 17 Nov 1999 19:51:53 -0800
- To: www-rdf-interest@w3.org
Hi Dan, could you show how this could for my original problem? How do i change my editor, such that i can add metadata to HTML pages, but i don't have to copy the text out of the HTML-page? Ciao, Stefan At 10:15 PM 11/17/99 -0500, you wrote: >On Thu, 18 Nov 1999, Renato Iannella wrote: > > --On 17/11/99 4:30 PM +0200 Ora.Lassila@nokia.com wrote: > > > > > Stefan, > > > > > > you raise a very interesting question. As I recall, it was actually > at one > > > time discussed in the RDF working group. > > > > And I remeber it like it was yesterday ;-) > > > > I unsuccessfully argued for a facility in RDF syntax to differentiate > > between a URI being used to *identify* another resource (which we have > > now with "resource=" attribute) and a URI that is a link to more RDF > > that _could_ be dereferenced (with a new attribute "metadata="). > > > > For W3C Memebers you review the thread starting at: > > > > http://lists.w3.org/Archives/Member/w3c-rdf-syntax-wg/1998Dec/0007.html > > > > I still think that this is a _useful_ facility for the "Semantic Web" > >See also the 'seeAlso' property in RDF schema, which can be used for >exactly this. > > 2.3.4 seeAlso > The property rdfs:seeAlso specifies a resource that contains > information > about the subject resource. This property may be specialized using > rdfs:subPropertyOf to more precisely indicate the nature of the > information the object resource has about the subject resource. > >This can be used as a hint in the case of self-describing resources. > > >While syntactic abbreviations to tell us about self-describing uses are >certainly useful, I think it is worth making a point of the fact that >(a) this is just more metadata about something, and (b) there are a >variety of ways of acquiring metadata from a URI-named resource which >we'll want to reflect into RDF. It becomes a slippery slope as to when >'resource=' versus 'metadata=' would've been appropriate. > >For example: for many resources in the http:* namespace it might be >appropriate to use the HEAD HTTP method to find out more metadata, or use >WebDAV facilities, or send a content-negotation mimetype preference of >(for eg) text/x-rdf to express an interest in an RDF view of the object. >For resources in the z3950:* URI namespace, your RDF processor might want >to use other mechanisms, eg. the Z39.50 query protocol's EXPLAIN feature, >to acquire more RDF statements about the named resource. > >So... hardcoding 'metadata=' into our syntaxes (*not* the >model) might a be useful abbreviation for '[x]--seeAlso-->[x]', or >'[x]--dc:format-->"text/x-rdf"'. But figuring out strategies and commonly >agreeable patterns for acquiring RDF descriptions of a wider diversity of >resources (eg. HEAD, webDAV, EXPLAIN etc) strikes me as a more fruitful >activity. > >An example: >If I have an MP3 audio file online somewhere, or a JPEG, or whatever >data format. Each of these might have embedded metadata, using XML/RDF or >some other older encoding. Using metadata= doesn't help here; instead we >want to figure out how to extract data from each of these formats, either >(?ideally) server side, otherwise, clientside or via some 3rd party >service. Eg. media file URI is http://purl.org/net/danbri/bigpicture.jpeg >We could either download the JPEG, and look inside for metadata. Or we >could pass a reference to it to some specialised RDF Description Service, >eg. >http://www.tasi.ac.uk/imagemetadataextractor?http://purl.org/net/danbri/big >picture.jpeg >(which might return us an rdf/xml description of that object). Or else we >could ask the server itself for metadata about that object, perhaps using >content negotiation or WebDAV or HEAD. > >Longwinded point being that there's a world of possibilities and the >'metadata=' syntactic suger addresses only a % of the scenarios that >RDF-aware software systems will be grappling with... > >Dan > >
Received on Wednesday, 17 November 1999 22:52:05 UTC