Status of this Document: draft for discussion
The [proposed] DCMI Architecture WG continues and draws together the work of the Datamodel, Schema and Implementor working groups. With the ratification of an initial set of exemplary Dublin Core qualifiers by the DCMI Usage Committee, there is a need to provide clear, principled and consistent guidelines for deploying Dublin Core metadata applications.
Working Group Charter:
The objectives of the working group are to discuss and develop a model, strategy and roadmap for the practical deployment of Dublin Core metadata using mainstream Web technologies (XML/RDF/HTML).
The following deliverables are anticipated...
Note: lead editors/authors/volunteers are tentatively listed. An early deliverable of the WG consists of a more formal tasklist, including dated checkpoints and confirmed contributors. The exact set of deliverables may differ from those drafted below.
DCArchTasklist: DCMI Architecture tasklist, enumerating works in progress and associated timescales (WG chair(s))
DCSimpleSchema: Dublin Core Metadata Elements (unqualified) in RDF-compliant XML DTD (Dave Beckett) [working draft]
DCArchRoadmap: DCMI Architecture / roadmap document (volunteers: DanBri, Tom, Eric, Carl, Rachel, Ren)
DCRDFModel: Guidelines on RDF Model representation of Qualified Dublin Core (revision of existing doc) [working draft]
DCQualSchema: An RDF-compliant XML DTD for Qualified Dublin Core (volunteered: Dan Brickley, Dave Beckett, Eric Miller)
DCQualHTMLMETA: Dublin Core Qualifiers (HTML encoded META) (Simon Cox; (+reference Dan Connolly's XSLT work?) [working draft]
DCQualNatLang: A natural language expression for qualified Dublin Core metadata sentences (Tom Baker) [draft in progress?]
This working group addresses two requirements commonly articulated by metadata implementors in the Dublin Core community. Firstly, there is a need for simple, short and practical specifications describing Dublin Core deployment strategies using HTML, XML and RDF. Secondly, there is a need for architectural consistency across these complementary specifications, and some broad 'overview' or roadmap materials providing a readily comprehended view of how these various activities fit together.
The Architecture WG is in particular expected to address the need for an RDF-compatible approach to DC deployment that interacts well with mainstream Web technologies such as HTML and XML.
Regarding HTML, the WG should build upon the qualified DC using HTML meta draft, the additional possibilities provided by the recent W3C XHTML 1.0 Recommendation, and the transformational capabilities of Extenstible Stylesheet Language (XSL). The use of XSLT for transforming between XML-based data formats provides a number of strategies that the DCMI Architecture WG will need to explore. XSLT can, for example, be used to transform various XML dialects (eg. XHTML, or data written to proprietary DTDs) into formats more suited to interchange or aggregation (further reading: danc-0101, danc-0026).
The goal of the WG is to provide enabling technology to support the deployment of rich metadata modeling and description based on existing specifications from DCMI, W3C and elsewhere. WG members will therefore need some understanding both of various relevant technologies (XML,RDF,HTML,XHTML,XSLT...) and of the kinds metadata applications Dublin Core and RDF are being applied to.
It is not a goal of this WG to undertake any actual data modelling work, ie. we do not aim to redescribe the entities and relationships described in Dublin Core (and related) metadata structures. Rather, we are attempting to articulate deployment strategies that allow such data modeling activites to be conducted in a more decentralised fashion. The recent simplification of the DCMI's approach to qualifiers is indicative of a broader shift towards a model in which the DCMI Usage Committee plays the role of endorser rather than creator with respect to new metadata vocabulary elements. The central challenge addressed by the Architecture WG is to specify practically implementable mechanisms by which (qualified) Dublin Core data structures can be deployed, and presented as candidates for endorsement by the Usage Committee. These mechanisms will need to embrace not just the exemplary DC qualifiers recently ratified, but other such qualifiers specified according to the principles adopted by the DCMI Usage Committee.
Open issues regarding the DCMI Architecture WG proposal:
The RDF Interest Group provides an active forum for discussion amongst RDF/XML metadata implementors.
The open metadata registry testbed contains links to draft rdf schema for many Dublin Core qualifier constructs.
Authors: Dan Brickley <firstname.lastname@example.org>, Sigfrid Lundberg <email@example.com>