On Thu, 10 Feb 2005, Rachel Heery wrote:
> (sorry for X-posting, can WG chairs indicate on which list this discussion
> is best placed?)
Errr... I'm not sure to be honest.
> On Thu, 10 Feb 2005, Andy Powell wrote:
>> Owners of such terms have to explicitly acknowledge that the terms are RDF
>> properties (or at least declare them in such a way that they are able to
>> be treated as RDF properties) before they can be used in DC application
>> profiles. In practice, I suggest that this means that the semantics of
>> these terms should be declared using RDFS.
> I think your bracketed statement needs more explanation... it would be
> helpful to be clear as to how terms can be 'declared in such a way' that
> they can be used as RDF properties. Even allowing for the constraints of
> the DC data model, there seems to me some wriggle room to enable mixing
> and matching where 'owners' of terms are willing to co-operate.
> As I understand it the process for re-use of MARC relator terms was an
> initial agreement that (some of) the relator terms would be useful within
> DC records, then going through the formality of 'declaring' such terms as
> RDF properties
That's correct - and is exactly what I am suggesting needs to happen in
every case where we want to re-use existing 'elements'.
> I think it is the fact that the owner is willing to declare these
> terms 'outside' the rest of the MARC data model, as RDF properties that
> makes it ok to mix and match?
> within the MARC data model and MARC records
> the relator terms do not act as 'properties' as I understand it - the
> terms have a different role in MARC records than within DC records.
I think that perhaps 'different role' is open to an interpretation that is
too strong - but basically I agree with what you are saying here.
marc:artist has essentially the same semantics whether it is used in MARC
or in DC but it is being used in the context of different underlying
> This seems to make declaring terms as RDF properties something of a
> formality - as long as the maintainer or 'owner' of data element sets is
> willing to declare a particular sub-set of terms as RDF properties then
> that is ok...
> In my view the criteria for re-use of terms should be something like:
> "First, are the semantics and context of a term in one metadata format
> sufficiently similar to the semantics and context of the property I want
> to express in a DC description? if so can this term be usefully used in
> 'isolation' within a DC description out of the context of its original
> Second, are the 'owners' of the terms willing to co-operate?"
Agreed on both counts - this is what I meant by 'explicitly acknowledge'
> If the answer to both of the above is yes, then declaring those terms as
> RDF properties may well be achievable. Especially if, as I understand has
> happened with MARC relator terms, just the sub-set of terms required from
> the 'other' format based on a different data model need to be declared??
I think that all the MARC relator terms have been declared. But it
doesn't really matter - there would be no problem with only declaring a
> Maybe worth thinking about that old saying 'everything can be solved by a
> level of indirection'.... not knowing much about MODS, but could a sub-set
> of MODS terms be 'separated out' of MODS and declared as RDF properties?
Yes, that could happen. By 'separated out' I assume that you mean
assigned URIs that are different to the current MODS namespace URI?
One of the 'best-practice' issues that we need to think about is whether
the namespace URI associated with the mods:url used in MODS/XML should be
the same as the namespace URI associated with mods:url used in DC/XML (and
As an example, what I think Mikael has done with his RDF version of LOM is
to re-declare the LOM 'elements' as RDF properties using a different
namespace URI. These LOM/RDF properties become usable in DC descriptions
in a way that the original XML Qnames used in LOM/XML instances are not.
> In my view we should be looking for solutions to help us meet requirements
> of several user communities, and to move forward as regards the evolution
> of data element sets by allowing re-use of data elements. If this can be
> done by declaring sets of terms in RDFS then good....
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