Bill,
Thanks for the initial comments. I agree with your critique, however the
omission of a leading context was intentional. I intended my Warwick
Framework section to be an embedded section of a larger document. Sorry
that I didn't make this clear but my vision of a larger document was:
- An overview of the metadata effort as carried out by the Dublin workshop
and then this follow-on workshop.This is the context that you have made a
stab at, I assume.
- A review of the notion of a core metadata set as represented by the
Dublin core.
- A description of how to incoporate core metadata in rthe existing WWW
framework (I have a back reference to this in my section). I believe that
Lou Burnard, et.al. have already made an effort at this at
http://info.ox.ac.uk/~lou/wip/metadata.syntax.html.
- The Warwick Framework section as I wrote it.
Sorry if I misunderstood my "assignment". To be honest, I never find it
easy to write a piece of something for which I don't have a sense of the
"whole" yet. I'd be glad to make a stab at the earlier sections but I
think that Stu and/or others who started this whole effort might be a
better "context setter".
As for you text, I really like parts of it but I think it starts to get too
"architectural" (read, Kahn/Wilensky-ish) towards the end. I think context
should be devoid of architectural prejudice and stick to higher level
motivations.
Which all brings up the issue of who is driving this bus (Stu, are you
there?) I'd be glad to play the lead authorship role for the entire
workshop report, but I feel uncomfortable grabbing that role through
"chutzpah" rather than agreement. I think at this point we need to define
the "authorship committee". We have a number of parts and they feel at
least workable. Can we put together a crew of no more than four people (I
will be the first volunteer) and decide on some clear goals on when/what we
want to get out.
Carl
----------
From: William Y. Arms[SMTP:[log in to unmask]]
Sent: Wednesday, May 01, 1996 12:01 PM
To: Carl Lagoze
Cc: [log in to unmask]
Subject: Your metadata draft
Carl,
I had a quick look at your paper today. More detailed comments will follow
, but my first reaction was that it lacks an overview to motivate the
concepts that follow. Here is my attempt at an introduction. Please feel
free to extract anything that is useful.
Bill
=======
Overview
In March 1995, OCLC hosted a meeting to discuss metadata for items of
digital information. The major result of that meeting was a list of
thirteen metadata elements that can describe a wide variety of items. This
list has become known as "the Dublin Core".
A year later a follow up meeting was held at the University of Warwick to
review progress and plan future steps. Three key concepts came out of this
meeting. Collectively, they have been nicknamed "the Warwick Framework."
Metadata Packages
Although many groups are building information services with metadata drawn
from the Dublin Core, every group is adding extra metadata elements. The
additions may be subject specific (e.g., for geo-spatial data), technical
(e.g., formats or protocols), structural (e.g., links to show relationships
between complex objects), or business related (e.g., terms and conditions
for usage).
To handle this need, the Warwick meeting proposes a set of metadata
packages. For example, the Dublin core is one package; another might be
the terms and conditions package. An information service can select one or
more packages to provide metadata for a set of objects.
This approach has several advantages over selecting individual metadata
elements from a very long list of elements. Packages can be very
different. For example, a package that expresses relationships among
objects might use abstract data structures. A reasonably small list of
well defined packages is hoped to enhance interoperation and lead towards
standardization of practices. In addition, as described below, packages
allow flexibility in the development of a security architecture.
Security
When a digital object is accessed over a network, there are many occasions
when a supplier wishes to make only part of the metadata accessible to
specific users. For example, an organization may need to have access to
technical metadata in order to store and transmit information, but, to
avoid potential liability, may explicitly desire not to have access to
metadata that describes content. A commercial organization may wish to
provide some metadata openly, but require authorization before giving
access to other metadata.
These objectives can be achieved by providing each metadata package with
its own security. Access controls on each package can be different.
Representation of Metadata
There will undoubtedly be many different representations of metadata within
repositories. For example, the metadata for a digital item can be embedded
within the item or external but associated. Much of the work on
repositories uses the concept of a "digital object", in which the metadata
and the data are both stored within a repository without the details of the
storage mechanism being known externally.
Formats for exchanging metadata between systems need to be clearly defined,
flexible, yet easy to use. Preliminary work carried out during the Warwick
meeting convinced many of the people attending that SGML provides a
suitable format to represent metadata packages. The meeting considered
that Web pages in html format are such an important special case that they
deserve special attention. The meeting proposes a syntax based on the html
"meta" tag.
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