Re: SemWeb Non-Starter -- Distributed URI Discovery

I believe the biggest problem is the concept of "uri owner".
While there are is clearly interesting use cases where querying the "uri 
owner" in needed and or useful, there are probably more where this makes 
not much sense.
URI are not dereferenciable in general, just a very small subset is. An 
even bigger problem is what one wants to refer to something that doesnt 
have an "owner" using an in fact
dereferencialbe URI, e.g. referring to Mozart using some 
example.org/myfavouritemusicians/mozart#
in this case how do you know he is really "the authoritative" ? what 
about some other Mozart fan?

Even if it was the authoritative then do you really want to know what it 
has to say? of course yes, but will you get fair "reviews" for example?
One of the nice things of the SW if not the nicest is that in theory 
anyone is entitled to talk about anything that has a uri. .. So a "uri 
centric" query interface
is inherently complicated, albeit very desirable ("i dont where it is 
written, please tell me what do you know this") .

[adv :-)]
That is why we came out with RDFGrowth, an approach where your peer will 
greedily collect all other people know about URIs that he is interested 
into. [1]
[/adv]

About "SPARQL Protocol for RDF", yes it is meant to provide the ability 
to ask a server about a URI, anyway if you want to test something now i 
suggest nokia uriqa implementation

Giovanni

[1] 
http://semedia.deit.univpm.it/submissions/ISWC2004_workshop_p2p/RDFGROWth_workshopISWC2004.pdf


Stephen Rhoads wrote:

>Until today, I considered myself to be squarely in the "slash" camp in the hash/slash debate.  Then something occurred to me which has got me all upset because it has serious implications for my project [1] -- which is inherently distributed in nature.
>
>As far as I can tell, there is no formal, generalized mechanism to reliably query the owner of a URI in order to obtain an RDF Description of that URI.  And this is a serious impediment to the Semantic Web.
>
>"hashing" at least gets you part of the way because -- given an HTTP URI containing a hash and frag ID -- it is *likely* that one can dereference the URI into a document containing (amongst other things) an RDF description of the URI in question.
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>For example, if I encounter the URI
>
>http://www.somemediacompany.com/rdfdata/music/classical#resource
>
>chances are I can dereference “http://www.somemediacompany.com/rdfdata/music/classical” and find within that document an RDF description of “#resource”.
>
>If, one the other hand, I encounter
>
>http://www.somemediacompany.com/rdfdata/music/classical/resource
>
>then I can’t make any assumptions about whether or not this URI refers to some sort of document containing an RDF description of “resource”.  The URI owner may just have chosen to mint URIs using some logical hierarchy.
>
>So, given an arbitrary URI, how can I obtain an RDF Description of that URI?
>
>I suppose I could crawl the domain “containing” the URI with a spider and harvest RDF data until I find the description I’m looking for, but that’s a bit of a mess.  And it certainly doesn’t scale.
>
>I read up a bit on SPARQL -- particularly the "SPARQL Protocol for RDF" -- and, unless I'm misunderstanding, it seems to be the intended long term solution to the problem described herein.  Is that correct?  Is it expected that URI owner/minters will operate some sort of SPARQL server for providing RDF Descriptions of their URIs?  Will there be some convention as to the location of these servers such that one can *reliably* and automatically query for an RDF Description of a URI?
>
>Have I framed this problem correctly?  Are there solutions or angles which I have missed?  Input would be greatly appreciated.
>
>--- Stephen
>
>[1] http://www.dmmp.org (Digital Media Metadata Project)
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Received on Friday, 18 March 2005 23:45:29 UTC