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XML and the DCMI Abstract Model DC Architecture WG Meeting, DC-2005, Madrid, Spain, Monday 12 September 2005 Pete Johnston Research Officer, UKOLN, University of Bath. UKOLN is supported by:. www.bath.ac.uk. DCMI Abstract Model and Bindings.
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XML and the DCMI Abstract Model DC Architecture WG Meeting, DC-2005,Madrid, Spain, Monday 12 September 2005 Pete Johnston Research Officer, UKOLN, University of Bath UKOLN is supported by: www.bath.ac.uk
DCMI Abstract Model and Bindings • DCAM describes conceptual model for DC metadata description set • types of construct • relationships between constructs • Description sets encoded/serialised as records • Binding describes mapping between constructs in conceptual model to components in syntax • Two way • encoding application: description set -> record • decoding application: record -> description set
DCMI Abstract Model and XML • DCMI provides multiple "encoding guidelines" specifications • XHTML, RDF (Simple, Qualified), XML • Guidelines for implementing Dublin Core in XML (2003) • DCMI Recommendation • XML binding for DC metadata • Mapping between constructs in conceptual model to components in XML syntax • XML elements (names, content), • XML attributes (values) • Other non-DCMI XML bindings for DC deployed
DC-XML-2003 and DCMI Abstract Model • DCAM Appendix C • features of DCAM supported by DC-XML-2003 • However, DC-XML-2003 pre-dates DCAM • maps conceptual models to XML • but does not map DCAM to XML • provides own models • "Simple DC Record" • "Qualified DC Record • DC-XML-2003 models different from DCAM
DC-XML-2003 models and DCMI Abstract Model (1) • Same/similar concepts, different labels
DC-XML-2003 models and DCMI Abstract Model (2) • Concepts present/omitted
DC-XML-2003 models and DCMI Abstract Model (3) • Concepts conflated
Problems • Attempts to encode/decode conceptual constructs not present in DC-XML-2003 models • resource URI • value URI • vocabulary encoding scheme/syntax encoding scheme distinctions
DC-XML-2003 models and DC-XML-Binding (1) • Syntax examples with no mapping to DC-XML-2003 models (section 6) • ODRL, IMS-LRM XML fragments • XML sub-tree constructed according to rules of second XML format • XML sub-tree has no interpretation in DC-XML-2003 • Contradicts rationale for specification • error in specification?
DC-XML-2003 models and DC-XML-Binding (2) • Binding "encoding schemes" to XML Schema datatypes • XML Schema datatypes apply to XML element content, XML attribute values • syntax encoding schemes? • but default type always present? • Datatype derivation problems • trying to introduce support for rich representations at syntax level
Problems • Section 6 encourages merging of arbitrary XML fragments • hybrid document with no interpretation • "undermines" mapping to DCAM! • Mapping "encoding schemes" to XML Schema complex types • can't work for both vocabulary encoding schemes and syntax encoding schemes • Complex Type derivation problematic for some tools
Proposal • XML binding for DC explicitly based on DCAM • subset of DCAM? • full DCAM? • including review of use of XML Schema datatyping • Early drafts
Questions • Stay with (extended) DC-XML-2003? • emphasise that supports simpler model? • Maintain both (extended) DC-XML-2003 and DC-XML-2005? • emphasise that different models supported • Deprecate DC-XML-2003 and move towards support for DC-XML-2005 only?
XML and the DCMI Abstract Model DC Architecture WG Meeting, DC-2005,Madrid, Spain, Monday 12 September 2005 Pete Johnston Research Officer, UKOLN, University of Bath UKOLN is supported by: www.bath.ac.uk
