Theo said:
> Attached you find a proposal for a concept named as DCX. This
> proposal can also be found at
> http://krait.kb.nl/coop/tel/DCX_proposal.doc. There has
> already been some discussion on this subject before it was
> decided to send it to this list, soI copied and pasted the
> most recent messages below, assuming they also cover previous
> parts of the discussion.
As the comments from Tom and Andy note, I think there are two separate
aspects to this, which I think need to be separated out:
(1) a more generic abstract model for a DC metadata record that includes
the use of non-DC-owned terms, and provides a label for instances of
this type of metadata;
(2) mechanisms for improving the disclosure of the semantics of
non-DC-owned terms
I agree with Tom and Andy's comments that the first of these seems to
correspond to what some people have called a "DC Application Profile",
though stopping short of providing a specific label for this entire
class. (I'm not sure how useful it is to have such a generic label.)
For (2), the suggested solution is for DCMI to support the use of a
"catch all" "dcx namespace" that anyone (?) can use as the basis for the
URIs for any (?) of their (non-DC) terms.
I wonder whether this suggestion slightly mixes up two things, or at
least suggests a stronger relationship between then than is actually the
case:
- the "ownership" of a URI; and
- the ability of someone other than the owner to discover information
about the meaning of a metadata term identified by that URI.
I'd argue that it makes no difference whether a term has a URI of
http://purl.org/dc/dcx/myterm or http://dublincore.org/dcx/myterm or
http://purl.org/tel/terms/myterm or
http://www.europeanlibrary.org/terms/myterm as regards my ability to
find out what the term means.
My ability to find information about the meaning of any term
defined/owned by someone else depends on people following shared
social/administrative conventions about disclosing that information,
whether that involves
- the owner/creator of the URI making that URI "dereferenceable" (for
the full "lifetime" of the term) and ensuring that dereferencing it
generates some useful information; and/or
- the owner/creator of the URI "depositing" information about the term
it denotes with a global or community-wide service (e.g. a registry)
that I know about and can access and use (It's no help to me if the
information is registered with a service I don't know about or can't
access)
(If you regard the Web itself as the registry, then maybe the first is
just a special case of the second.)
I just don't think that information about terms with URIs beginning
http://purl.org/dc/dcx is somehow _intrinsically_ more "discoverable"
than information about terms with URIs beginning
http://www.europeanlibrary.org/ or http://myproject.org/. It's the use
of shared procedures and conventions (including considerations about
dereferencing and persistence) that make that information
available/accessible to other people. DCMI has explicitly addressed this
for the URIs it owns/creates in the namespace policy document (which I
think would be better titled a _URI_ policy document, but that's by the
by!) and in DCMI Usage Board implementation of that policy in its
procedures.
To address (2), it seems to me we need
(a) improved understanding of the _responsibilities_ associated with
declaring metadata terms and assigning URIs to them (I don't deny that,
as Andy said in one of his messages, there may be some diffficult issues
in terms of persistence if such URIs are being created in the context of
short-term projects);
(b) shared, consistent practices for the _disclosure_ of information
about those terms and URIs
I don't think either (a) or (b) requires the use of a catch-all "dcx
namespace", and indeed creating a "dcx namespace" for people to use as
the basis of their URIs wouldn't in itself address the problem: it's the
conventions and policies that do that.
In terms of disclosure "services", one practical measure for DCMI to
consider might be whether the DCMI registry (or a DCMI-provided registry
implementation) indexes data for terms from sources other than DCMI
(though I'd suggest there would need to be some control on what was
indexed.)
Pete
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