- From: Phil Archer <parcher@icra.org>
- Date: Thu, 02 Aug 2007 09:36:19 +0100
- To: Semantic Web <semantic-web@w3.org>
This discussion seems to have forked but I'll try and shed light on this sub-query. Garret Wilson wrote: [..] >> >> [] a wdr:ResourceSet; >> wdr:includeSchemes "mailto"; > > This is very interesting. Two questions. First, how stable is this? > Should the namespace http://www.w3.org/2007/05/powder# change? The namespace is as stable as any public draft. That is, it would be wrong to assume that the work we're doing will continue smoothly along the track to Recommendation without changes, we don't foresee a change in the namespace itself. Further, such review as there has been of the work to date has not challenged the general principles we're working on. That may change, of course, but for now we're confident in the general approach. There'll be a new draft of the doc [1] next month. > > Secondly, how do I specify "all resources"? (In my case, some resources > may use mailto: URIs, others may use UUID URIs.) Am I stuck with the > following, or is there a shorthand representation? > > <wdr:ResourceSet> > <wdr:includeUriPattern>*</wdr:includeUriPattern> > </wdr:ResourceSet> Our work is, of course, driven by its use cases. Ours are centred on things like trustmarks, standards compliance and, potentially, licensing. In all those scenarios you need to be describing a defined set of resources, typically those collected in a Web site. Therefore we believe some restriction on what is being described is necessary and we define <wdr:ResourceSet /> as the empty set. That said, your example raises an issue we've not discussed, i.e. what if the RS definition is tantamount to the universal set. Hmmmm... A thought, you can define Resource Sets as unions of other Resource Sets so if you wanted 'everything with a mailto: scheme or a UUID' that shouldn't be hard. And the whole thing is extensible anyway so defining your RS to include what you want and not everything else should be possible (or we've goofed on the whole thing!!) The basic model to remember is that you start with a known 'candidate resource' and then see if it matches the properties defined in the RS. If it does, it's an element of the RS. Without the starting point of a known resource, Resource Set definitions don't work (this is all set out in the doc). However... there's more to POWDER than Resource Sets. The Description part is potentially more generic. I'm not sure if this helps but we are defining a Class called Descriptors - and this is where we step outside the RDF model - the properties of which are applied to whatever the subject of triple may be. So, for example, the basic nuts and bolts are already in place on my.opera.com whereby you can tag anything you like and then link that tag to a pre-defined Descriptors class. My own area of child protection leads me to define things like 'xxx' and 'gambling'. You can call it what you like but if you link your tag to http://repository.icra.org/generic#xxx the thing you're tagging will also have a description that is anchored in something with defined semantics. The crucial point being that the properties of the Descriptors do not describe the tag, but the resource that the tag describes. Hope this helps. Phil. [1] http://www.w3.org/TR/2007/WD-powder-grouping-20070709/
Received on Thursday, 2 August 2007 08:36:46 UTC