RE: Not needed? Distributed URI Discovery

is this really a distinction between URI and URL ? here's a snippet from rfc

A URI can be further classified as a locator, a name, or both.  The
   term "Uniform Resource Locator" (URL) refers to the subset of URI
   that identify resources via a representation of their primary access
   mechanism (e.g., their network "location"), rather than identifying
   the resource by name or by some other attribute(s) of that resource.

The Semantic Web (as far as I can tell) relies upon URI (identifier), which
may or may not be a URL (network-retrievable thing).  I think this is the
root of the problem.  Stephen originally asked for a way to convert a URI
into a URL in order to obtain data or metadata about the thing to which the
URI refers.  Moreover, Stephen seems to echo the sentiments of Tim
Berners-Lee, but extending these sentiments to the Semantic Web:

"The Web works because, given an HTTP URI, one can in a large number of
cases, get a representation of the document."

I don't have an answer to the problem, but I think the distinction between
URI and URL is pretty important, and the confusion between the two has lead
me into long nights of confusion.


(I'm still reading thru the archives that someone else posted from the 
-----Original Message-----
From: Benjamin Nowack [] 
Sent: Thursday, March 24, 2005 12:25 AM
To: Max Voelkel
Subject: Re: Not needed? Distributed URI Discovery

On 23.03.2005 21:32:22, Max Voelkel wrote:
>>>At present, there is no formal, generalized mechanism whereby a Web
>>>upon discovery of a URI, and lacking knowledge about that URI, can query
>>>Originator of the URI in order to obtain an RDF description of the URI.
>Lets compare URIs with symbols. When I discover a new term, I can not
>ask the term, what it means. I ask a knowledge source (friends, books,
>search engine) about it.
>Why do we have to make things different on the web? When I find
>a RDF document with URIs I don't know i just ignore them.
When you come across an unknown non-web term, you ask a
knowledge source. If you don't want to make things different on
the web, you'll try to find a knowledge source for an unknown web
term or resource URI as well, won't you?

> If the RDF
>document was well-written it should contain rdf:seeAlso links to URLs
>of RDF-documents describingthe terms. Mights this be a solution?
Yeah, but we don't have an RDF document. All we start with is a
URI. The problem we discussed here was how to find this document
containing the description of the resource denoted by the URI (in
an efficient way), or how/where to serve this document in case
you are the URI owner/publisher...

Of course you can say that URIs are just labels and that noone
should try to find out more about resources identified by URIs,
but http-URIs have 95% of what is needed for automatic resource
description discovery already built in, it seems to be worth
the effort to find a solution for the remaining 5% in order to
help the semantic web grow faster. (damn tricky 5%, ok ;)


Benjamin Nowack

Kruppstr. 100
45145 Essen, Germany

>It is inspired by the WWW approach of links and by the design
>criterion of separation between identity (URI) and location (URL). I
>think also "_:1 rdf:type foo:isCrawlable" or similiar would be
>My conclusion is thus we need no index.rdf, no URI originator, no MGET etc.
>__ Location is not identity. __
>Ok, what if somebody else adds statements about a URI? Well, then i
>either need something like
>a) a search engine = centralized infrastructure or
>b) something like traceback = distributed, networked infrastructure
>   -> we need a standard for RDF-traceback-servers!
>I hope I inspired some people,
>Kind regards,
>University of Karlsruhe, AIFB, Knowledge Management Group
>room #258, building 11.40            

Received on Thursday, 24 March 2005 18:00:38 UTC