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Re: URI lifecycle (Was: Owning URIs)

From: David Booth <david@dbooth.org>
Date: Wed, 20 May 2009 01:01:47 -0400
To: Hugh Glaser <hg@ecs.soton.ac.uk>
Cc: semantic-web <semantic-web@w3.org>, Linked Data community <public-lod@w3.org>
Message-Id: <1242795707.12336.876.camel@dbooth-laptop>
Hi Hugh,

> > "The URI Lifecycle in Semantic Web Architecture":
> > http://dbooth.org/2009/lifecycle/

On Tue, 2009-05-19 at 18:08 +0100, Hugh Glaser wrote:
> Hi David,
> Excellent stuff.
> It is important, as you do, to make statements about what is good
> citizenship, and to distinguish these from what might be enforced etc..
> I was about to suggest that you might want a ³URI is deprecated² in your
> figure, but then I found that was the title of the Event 4 section
> corresponding to ³URI is obsolete². :-)

Oops!  Thanks for catching that error.  I've fixed it now.

> I suspect that this area could do with a bit of teasing out.
> For example, your description may indeed be ³obsolete², as it implies no
> access possible, and should never be a deliberate action by the owner (I
> suspect there might be another explicit part of URI owner responsibility 1,
> which is to serve the URI declaration for as long as they are able, or
> something like that). On the other hand, the owner may want to discourage
> use of some URIs in preference to others, so this is a deliberate act by the
> owner (I am thinking of opencyc in particular here), and this is the sort of
> thing I would term deprecation.

Yes, that's a good point.  I intended to include that case under the
overall "URI is obsolete" section (since the point is that the URI
should no longer be used to make new statements), but it looks like I
forgot.  I've added it now.

> It looks like an excellent research topic to provide theories and tools for
> determining when the responsibilities are being broken.
> A last comment, which I know we have discussed, and you possibly disagree:
> "Community expropriation of a URI"
> Might have meant something else.
> One of the problems is that many authors will not discharge their Statement
> Author Responsibilities, but will assume that the URI is the one they want.
> Over time, this may mean that the general SW uses a URI in a way other than
> the URI owner intends, to the extent that it becomes irrelevant what was the
> original meaning (there are many parallels for this in natural language, and
> indeed it is the social process that causes language to change).
> [ . . . ]

Yes, that's a great topic for discussion.  It is clear that semantic
drift is a natural part of natural language: a word that meant one thing
years ago may mean something quite different now.  As humans we can
usually deal with this semantic drift by knowing the context in which a
word is used, though it can cause real life misunderstandings sometimes.

However, I think our use of URIs in RDF is different from our use of
words in natural language, in two important ways: 

 - RDF is designed for machine processing -- not just human
communication -- and machines are not so good at understanding context
and resolving ambiguity; and

 - with URI declarations there is a simple, feasible, low-cost mechanism
available that can be used to anchor the semantics of a URI.  

In short, although semantic web architecture could be designed to permit
unrestricted semantic drift, I think it is a better design -- better
serving the semantic web community as a whole -- to adopt an
architecture that permits the semantics of each URI to be anchored, by
use of a URI declaration.  

For more explanation see: "Why URI Declarations? A comparison of
architectural approaches"

David Booth, Ph.D.
Cleveland Clinic (contractor)

Opinions expressed herein are those of the author and do not necessarily
reflect those of Cleveland Clinic.
Received on Wednesday, 20 May 2009 05:02:25 UTC

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