Scenario: Dublin Core

The Dublin Core Metadata Initiative (DCMI) http://dublincore.org/ has
been working with web metadata since 1994 producing the Dublin Core
Metadata Element set (DCMES) and related work.  I have been involved
with this work since 1995 and co-edited:
  Expressing Simple Dublin Core in RDF/XML
  http://dublincore.org/documents/2002/07/31/dcmes-xml/

  Aside: Which has a DTD and W3C XML Schema for this constrained
            profile of RDF/XML.

DCMI recommends a way to embed the DCMES in HTML and XHTML which
preserves validation. This has been found to be important to the
community.

The approach currently recommended:
  Encoding Dublin Core in HTML (RFC 2731), John Kunze, 1999-12-1
  http://www.ietf.org/rfc/rfc2731.txt
is to use the <meta> and <link> tags (see above for details).

This allows flat (property: value) DC metadata to be written in HTML
to describe one thing - the document - but does not allow richer
description such as describing the document, creator, publisher,
other items in detail and relating them.

In addition, the set of terms is extended by a mechanism using
<link rel="schema*"> to pull in addition terms outside the DC element set.
The DCMI calls the latter the Qualified Dublin Core model allowing the
use of a growing set of terms which are described in the DCMI Terms and
Types documents.  Pointers to these at http://dublincore.org/documents/

There is a draft version of a new document:
  Expressing Qualified Dublin Core in HTML/XHTML meta and link elements
  http://www.ukoln.ac.uk/metadata/dcmi/dcq-html/
which still uses the flattened model (only describing one entity) but
allowing the extra terms from the DC documents and others.

RDF was designed to implement DC on the web and as such should
support writing the qualified, richer DC model in HTML.

Trying to pull out some of the detail:

  * Expressivity must go beyond flat (the existing RFC handles that)

  * Validation of (X)HTML required

  * The terms used in the DC model written as RDF-in-XHTML must be
    easily extendable to handle new DCMI terms, types, etc.

  * Preferably terms are related to their namespace URI

Dave

Received on Tuesday, 24 June 2003 08:12:06 UTC