On Mon, 22 Sep 2003, Andy Powell wrote:
> I'm not sure what 'people' you are referring to here? As far as I know,
> the term 'related metadata' is *only* used in my draft document? Within
> that document, it is used as defined (I think).
Is the question rather as to whether it is worth addressing within the
model linking to 'external metadata' about the same resource? It seems to
me this sort of linking might be quite useful for 'modularising'
It is dealt with explicitly by the METS document mark-up
External Descriptive Metadata (mdRef): an mdRef element provides a URI
which may be used in retrieving the external metadata. For example, the
following metadata reference points to the finding aid for a particular
digital library object:
> > (a) More metadata about a resource that there is no appropriate DC
> > property for. Where metadata is encoded as XML the DC in XML
> > guidelines give examples of this as 'mixed' metadata.
> > (b) The same metadata as in the DC property fields, but encoded
> > using metadata properties from a different namespace.
> I'm not aware of 'related metadata' being used to mean either of these -
> not in the abstract model draft at least.
> > (c) A combination of (a) and (b).
> > (d) Metadata about a related resource.
> > (a, b, c) are in fact encodings of application profiles.
> > I'm a bit unsure about (d). It implies I could include in a DC record
> > for a journal article metadata about other articles that the article
> > references, using dcterms:references. Doesn't this break the
> > principle (1-1?) that a DC record for a resource should not include
> > metadata for another resource?
> No, it does not do this. Quite the opposite. One of the purposes of the
> model is to make it clear that 'related metadata' is *not* part of the
> abstract 'record' and that all the properties in the record *must* be
> attributes of the resource being described. Hence the abstract model
> completely endorses the 1:1 principle.
> Now, it may be the case that a particular encoding of instance metadata
> (e.g. the RDF/XML encoding) may embed descriptions of multiple resources
> within a single instance document - but that is a syntax issue. But by
> looking at the way a particular syntax implements the abstract model, it
> is possible to see that the 1:1 principle is preserved in the abstract
> > Or is this document an attempt ot
> > relax that rule, reflecting that in reality people are creating records
> > that include related metadata?
> Again, no. The abstract model tries to clearly separate out the
> descriptions of different resources when more than one resource is being
> described. That is the whole purpose of introducing the notion of
> 'related metadata'.
> > Later in the Abstract Model, DCSV is defined as a labelled string,
> > and that it should be treated as related metadata. This seems to
> > be using 'related metadata' as in (a,b,c) in some cases. Period,
> > Box and Point are giving more, or more precise, metadata about
> > the resource itself not about a related resource.
> Not really... period, box and point give 'related metadata' about three
> related resources - a 'period in time', a 'box in space' and a
> 'point in space'. These three things might be fairly abstract concepts,
> but they are nonetheless resources.
> > The now defunct
> > DCMICite was providing more metadata about the resource, for
> > which there was no appropriate DC property, not metadata for a
> > related resource.
> I agree that the DCMICite proposal does raise a slight problem with my
> definition of 'related metadata'. dc:identifier is something of a special
> case. Because the value URI for dc:identifier is the URI of the resource
> being described, if there is 'related metadata' associated with that
> property, then is is metadata about the resource, and not metadata about a
> related resource. This is also true for any element refinements of
> dc:identifier. I need to think a bit more about this. I'm not sure how
> best to handle it.
> > Though the Vcard example is metadata about a
> > related resource.
> > So does the Abstrat Model document also need to include
> > something about mixed metadata / application profile?
> I think it probably does - but not for the reasons you outline above :-).
> My current plan is to re-draft the document with an initial section that
> covers an abstract model for DCMI metadata (though I might label this an
> abstract model for DC[MI] application profiles). This model will then be
> refined into abstract models for qualified and simple DC. I think that
> will make the model cover what you are suggesting here.
> Distributed Systems, UKOLN, University of Bath, Bath, BA2 7AY, UK
> http://www.ukoln.ac.uk/ukoln/staff/a.powell +44 1225 383933
> Resource Discovery Network http://www.rdn.ac.uk/
University of Bath tel: +44 (0)1225 826724
Bath, BA2 7AY, UK fax: +44 (0)1225 826838