Greetings and best wishes for the new year,
The exchange on this list at the end of last year regarding DCAPs support for multiple descriptions
(see
http://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0412&L=dc-architecture&T=0&F=&S=&P=2827)
has prompted me to raise a couple of questions wrt description sets as
defined in the DC Abstract Model (DCAM).
The DCAM model defines a description set as:
'A description set is a set of one or more descriptions about one or
more resources.'
I think it would be helpful to model 'description sets' in more detail
(not necessarily in the DCAM document, perhaps as an additional document).
It is not clear to me how the different descriptions in a description set
are distinguished - I cannot see any indication in the DCAM as to how
multiple descriptions of multiple resources are differentiated. I would
expect the relationships between descriptions in a description set to be
'modelled' in some way.
I have missed recent f2f discussion, so perhaps I am misunderstanding!
As I understand the DCAM definition of a description set, it suggests
descriptions can be grouped into a description set in an arbitrary way.
Am I right in thinking there is no necessity to relate the descriptions
together in any structured way?
In which case, how would one tell the difference between a 'description
containing statements about more than one resource' (which is
'non-conformant' with the DCAM) from a 'description set' (which is a
grouping of 'descriptions' or statements about multiple resources)?
Also I think it would be helpful to define the logical relation between a
'description set' and 'related descriptions'. (maybe this would be
something like: related descriptions always form a description set,
whereas a description set may contain unrelated descriptions?)
My feeling is that a description set needs to be structured by
establishing relationship between 'key values', and that structure would
usefully be represented in the abstract model?
So descriptions of a high resolution digital image, thumbnail and painting
might be linked by a common URI reference; a description set consisting of
'admin metadata' describing a description of a resource, and the
description of that resource would be related by a common identifier.
I have difficulty understanding how the DCAM can be entirely 'ignorant' of
such relationships? Elsewhere there are attempts to deal with the
complexity of such relationships eg. FRBR, METS, (MPEG DIDL?)... can the
DCAM attempt to group descriptions into sets without adressing a more
complex data model?
Rachel
---------------------------------------------------------------------------
Rachel Heery
UKOLN, University of Bath tel: +44 (0)1225 386724
http://www.ukoln.ac.uk
|