DC Architecture WG meeting
Wednesday 13.30 - 15.30
Seminar Room: 5205 (2nd Floor)

Review of the Abstract Model and moving forward
RDF resource vs. literal issue
XML schema issues
Identifiers for historical versions of metadata terms

Review of the year
(Sleepy Since Seattle)

…but not that sleepy!
Abstract Model document moved forward (slowly)
“Expressing Dublin Core in HTML/XHTML meta and link elements” issued as a DCMI Recommendation
discussion paper about assigning URIs for metadata terms
something like 200 messages posted to the dc-architecture mailing list

Abstract Model

Major changes
changed 'URI' to 'URI reference' at appropriate points throughout
added 'description set' to the description model to separate out the conceptual grouping of related descriptions (a 'description set') from its instantiation in a particular syntax (a 'record')

Major changes (2)
introduction of 'property/value pair' into the resource model to separate abstract notion of a property from the specific usage of a property to describe a particular resource
modified the definition of 'sub-property' in the resource model

Major changes (3)
added of a note about needing to indicate how 'resource URIs' and 'value URIs' are handled in encoding syntax specifications
explicit indication that 'resource URIs' and 'value URIs' are not supported by the current XML encoding guidelines
explicit indication that 'resource URIs' are not supported by the XHTML encoding syntax

Model summary

Remaining issues
possible need for further clarification of how URIs are handled by the AM – in short, dcterms:URI is almost never used and certainly not to indicate a ‘value URI’
it would be better if we modelled ‘syntax encoding scheme URI’ and ‘vocabulary encoding scheme URI’ as separate entities in the model

Remaining issues (2)
the AM currently restricts the number of ‘parent’ properties that a sub-property can have to a maximum of one - this is an error and will be made unlimited.
does the model get the definitions of ‘simple DC’ and ‘qualified DC’ right?
should the model support ordered lists of values?

RDF resource vs. literal issue

The problem

Possible solutions
Status quo
Align behaviour of consuming systems
Align behaviour of consuming and generating systems
Attempt to influence the behaviour of the wider Semantic Web community
Replicate existing DC property semantics in new properties

XML schema issues

Identifiers for historical versions of metadata terms

Slide 17

DC Architecture WG report
Abstract Model
encoding DC element values in RDF
XML schema issues
identifiers for DCMI term descriptions
21 attendees

Wot we did last year…
moved Abstract Model forward slowly
issued XHTML encoding guidelines as a Recommendation
developed issues papers on identifiers
about 200 postings to the
dc-architecture mailing list

Abstract Model
discussion around the meanings of ‘simple DC’ and ‘qualified DC’
no consensus
agreed to remove definitions of these terms from the Abstract Model
discussed possibility of adding support for ‘ordered lists of values’ to the abstract model – little support for this in the room

DC values in RDF
problem: some confusion in RDF implementer community currently
solution (short-term): work item to develop a short clarification document for RDF implementers
solution (long-term): work item to develop a view of possible ‘encoding’ changes to remove confusion and carry out impact analysis
undertaken by small ‘task force’

XML schemas
agreed to provide a persistent URI to the latest version of our XML schemes
agreed to provide two ‘container’ elements for DC descriptions, probably called <dcxml:description> and <dcxml:descriptionSet>
work item: revise DC in XML Guidelines to include explicit mechanism for value URIs

Namespace policy
work item: minimal update to the namespace policy to align some of the terminology with current usage
consider ways of documenting how we assign URIs to DCMI term descriptions