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Re: Perspective on the metadata / discovery struggle

From: David Booth <david@dbooth.org>
Date: Thu, 30 Jun 2011 12:01:44 -0400
To: Jonathan Rees <jar@creativecommons.org>
Cc: www-tag@w3.org
Message-ID: <1309449704.6147.35616.camel@dbooth-laptop>
On Thu, 2011-06-30 at 10:32 -0400, Jonathan Rees wrote:
> I had a thought about the TAG definition discovery and metadata
> architecture issues that might be helpful.  Probably this is obvious, but
> it wasn't to me so I thought it was worth writing down.  This relates
> to the fact that whenever the httpRange-14 thing comes up in the TAG
> we are confused about what issue to put it under. I was inspired to
> think this over by F2F remarks of Larry's about the magnitude of
> the problem.
> 
> There are two distinct application-level communication needs:
> 
>   1. web metadata - when I express information about a document
>      (image, etc.) how do I say (especially in RDF) that what I am
>      talking about is content that's accessed via a particular URI, as
>      opposed to other content
> 
>   2. definition discovery - given a vocabulary term (URI),
>      how is definition-like information for it discovered
>      (Definitions are not, in general, metadata.)
> 
> Described in this way, the needs seem unrelated.  The first falls
> under our ISSUE-63 (metadata architecture), the second under ISSUE-57
> (definition discovery).  The first need spawned the Resource
> Description Framework and the httpRange-14 2xx rule, while the second
> spawned linked data, RDF-style fragment ids, and GET+303.
> 
> The connection between them is that the same notation and protocol,
> namely what I've been calling dereferencable absolute URIs, has been
> advanced as a solution to both problems.  The competition creates a
> struggle.  Think of these URIs as a limited natural resource over
> which many factions are contending.  Just as a piece of real estate
> cannot be used for a wetlands and a high-rise at the same time, one of
> these URIs can't simultaneously get its meaning according to two rules
> that give different answers most of the time.
> 
> So the competition over "linguistic real estate" itself begets a third
> problem:
> 
>   3. to what referential use are dereferenceable absolute URIs best
>      put?
> 
> One might then give up and say interoperability is not a good goal,
> one might try to carve up or overload the linguistic space, one might
> try to "win", one might say it's an inadequate solution for one or the
> other problem, or that it's hopeless, and so on - all the arguments
> we've heard over and over again.
> 
> It's not enough to solve the three problems separately. There is
> no divide-and-conquer. That is what makes it so annoying: everything
> interacts.

Interesting observation.  However, it seems to me that although #2
clearly involves using the URI referentially, #1 does not *require*
using the URI referentially.  For example, instead of using
http://example/bar referentially by writing something like:

  :fred p1:authored <http://example/bar> .

to indicate that :fred authored the content accessed from
http://example/bar , one could just as well express this using a
different property like:

  :fred p2:authored "http://example/bar" .

in which the URI is used as a literal.  This seems like another way the
conflict could be avoided.



-- 
David Booth, Ph.D.
http://dbooth.org/

Opinions expressed herein are those of the author and do not necessarily
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Received on Thursday, 30 June 2011 16:02:07 GMT

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