From: Ballantyne, Mike
Sent: Thursday, February 26, 2004 9:29 AM
To: Smith, Michael K
Subject: FW: Dublin Core for Version metadata

See note about OWL group.

-----Original Message-----
From: Bijan Parsia [mailto:bparsia@isr.umd.edu] 
Sent: Thursday, February 26, 2004 12:45 AM
To: www-ws-desc@w3.org
Subject: Dublin Core for Version metadata



In the discussion about a version attribute, we've been focused on 
adding a version *identifier* to (I imagine) various parts of a WSDL 
(the WSDL itself, an interface, bindings, etc.). I suggested that, if 
possible, we shouldn't make up our own, but defer to some other 
standard, specifically Dublin Core, and just provide some guidance 
about how to use it.

I believe the current canonical set of Dublin Core terms is:
	http://dublincore.org/documents/dcmi-terms/

Most of the explicit versioning vocabulary are element refinments on 
dc:relation:
	http://dublincore.org/documents/usageguide/qualifiers.shtml#isVersionOf

so, isVersionOf, hasVersion, isReplacedBy, and replaces. Note that 
versioning here is entirely *relational*, i.e., these elements express 
various version relations, but do not express the "Degree" of the 
relation, i.e., whether something is a "minor" or "major" version. One 
could introduce such further refinements (and those refinements are 
trivial to express in RDFS and OWL).

Furthermore, I *think* it's in the spirit of dc;identifier to use it 
for version identifiers as well. Well, at least, it seems bendable in 
that way:
	http://dublincore.org/documents/usageguide/elements.shtml#identifier

There are "official" XML schemas for expressing dublin core metadata:
	http://dublincore.org/schemas/xmls/

And there are similar RDFS schemas as well.

Working through all this, my thought is that the current DC terms don't 
exactly, as they stand, replace the various proposals floating about, 
but they do provide a reasonable starting place. Personally, I'd rather 
see what ever proposal we thought we needed actually expressed in the 
Dublin Core framework, with whatever extensions necessary. Those 
extensions are unlikely to be WSDL specific and could end up stewarded 
by DCMI.

It seems that something like this would be very useful for the W3C as a 
whole. Many groups keep reinventing version properties, e.g., the OWL 
working group:
	http://www.w3.org/TR/2004/REC-owl-ref-20040210/#VersionInformation
They should have known better :)

It doesn't have the charm of  the simple quick bit of text that was the 
original proprosal. But I think something reasonable can be done. I'd 
be happy to work on it, edit a submission, and liase with DCMI.

Cheers,
Bijan Parsia.