On Thu, Sep 09, 2010 at 05:46:43PM -0400, Thomas Baker wrote:
> -- The Dublin Core Qualifiers were published in July 2000
> without reference to URIs [13] and without a corresponding
> RDF schema.
>
> -- A schema published in August 2001 [14] is the first RDF
> representation to show the "qualifiers" identified by URI.
> It uses the DC namespace "http://purl.org/dc/terms/".
It occurred to me after sending this that there was a crucial
step between July 2000 and August 2001 -- the creation of a draft
Namespace Policy in March 2001 [1] which, as I had forgotten,
used
http://dublincore.org/2000/03/13/dcq#
http://dublincore.org/2000/03/13/dctype#
as the DC namespaces for the "qualifiers" and Type vocabulary.
The September 2001 revision of the Namespace Policy [2] listed
these namespaces as they remain today:
http://purl.org/dc/terms/
http://purl.org/dc/dcmitype/
As a section "Justification" explained:
Two significant issues were raised during the development of this
policy. Firstly, that DCMI namespace URIs should indicate the
category of DCMI terms within that namespace. For example, it was
proposed that different DCMI namespaces might be used to partition
DCMI elements from DCMI qualifiers, or to indicate that a particular
term was originally defined by a particular community or within a
particular domain. Secondly, that all DCMI namespace URIs should
carry versioning information (for example a date stamp) that would
be updated as terms within the namespace change.
On the first issue it was considered that the category of DCMI terms
was not necessarily persistent. For example, terms defined initially
by the education community might subsequently become useful to other
communities. Associating particular URIs with particular categories
of terms was not felt to be helpful to the long-term stability of
DCMI namespaces or the URIs of DCMI terms within those namespaces.
On the second issue it was again considered that embedding versioning
information within the namespace URI was unlikely to be helpful
to the long-term stability of DCMI namespaces or the URIs of DCMI
terms within those namespaces. Rather, it was felt that versioning
information should be carried within the DCMI recommendations and/or
DCMI term declarations associated with DCMI namespaces and terms.
Finally it should be noted that, although the 15 elements currently
within the http://purl.org/dc/elements/1.1/ namespace could have
been redefined within the http://purl.org/dc/terms/ namespace, it was
considered that the widespread existing usage of the former namespace
URI mitigated against any change. Furthermore, the existing use of
the purl.org domain for that namespace URI prompted its use for all
DCMI namespace URIs.
Tom
[1] http://dublincore.org/documents/2001/03/09/dcmi-namespace/
[2] http://dublincore.org/documents/2001/09/17/dcmi-namespace/
--
Thomas Baker <[log in to unmask]>
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