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RE: [URNsAndRegistries-50] New issue on URNs and their uses

From: Bullard, Claude L (Len) <len.bullard@intergraph.com>
Date: Mon, 21 Mar 2005 11:18:55 -0600
Message-ID: <15725CF6AFE2F34DB8A5B4770B7334EE07206D03@hq1.pcmail.ingr.com>
To: "'ht@inf.ed.ac.uk'" <ht@inf.ed.ac.uk>
Cc: www-tag@w3.org

The first two scope items open up almost every permathread associated with 
the web since and before its inception.  This goes to the heart 
of the the URzed universe.  I see where it conflicts 
with a statement of good practice 1 that a namespace name should 
dereference a helpful resource and 2 the principle of a single 
URI per resource:

1.  A catalog can also be the helpful reference.

2.  This is unenforceable.  My personal rule of thumb is to 
    discourage policy that cannot be enforced.

Item 3 in the scope is itself a possible standardization task 
to encourage interoperability.  Otherwise, they have the role 
given them by their owners. (See two above).

Item 4 has educational value.


From: www-tag-request@w3.org [mailto:www-tag-request@w3.org]On Behalf Of

This note is to announce the opening of a new TAG issue which will be
known as URNsAndRegistries-50.


* What kinds of URIs are appropriate for naming XML namespaces?

* What is the role of location-independent names on the Web?

* What form should public registries for XML-encoded information take,
  if any?

* What are the tradeoffs between centralized and decentralized
  management of vocabularies, and how does this interact with Web

Issue background and related work

This issue was  accepted by the TAG during its telcon of Mar. 15, 2005 
(formal minutes not yet accepted by the TAG, but draft available at [2].) 

A number of proposals have emerged recently for the use of URNs or
URN-like names, including at least:

  URNs for namespace names:
   (e.g. http://ietfreport.isoc.org/idref/draft-ietf-geopriv-pidf-lo/
         http://xml.coverpages.org/UBL-NDRv10-Rev1c.pdf (section 3.4.2)

  Registries for mapping URNs or similar object to resources:
   (e.g. http://ietfreport.isoc.org/idref/rfc3688/

The TAG feels that on first inspection many of these proposals
interact with the principles set out in AWWW [1] in ways which need
detailed investigation.  Relevant parts of AWWW include:

   "[a] namespace URI can be used to identify an information resource
   that contains useful information, machine-usable and/or
   human-usable, about terms in the namespace. This type of
   information resource is called a *namespace document*.

   . . .

   Good practice: Namespace documents

   The owner of an XML namespace name SHOULD make available material
   intended for people to read and material optimized for software
   agents in order to meet the needs of those who will use the
   namespace vocabulary."

    -- http://www.w3.org/TR/webarch/#namespace-document

    "Good practice: Avoiding URI aliases

    A URI owner SHOULD NOT associate arbitrarily different URIs with
    the same resource."

     -- http://www.w3.org/TR/webarch/#avoid-uri-aliases

Issue namespaceDocument-8 [3] is also obviously related.

The TAG will consider all of the above in deciding whether there is 
a need to issue guidance in this area.

Next Steps

David Orchard and myself have been tasked with drafting an initial
survey of the issues involved.


[1] http://www.w3.org/TR/webarch/
[3] http://www.w3.org/2001/tag/issues.html#namespaceDocument-8
Received on Monday, 21 March 2005 17:19:26 UTC

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