Title:         RDF declarations of DCMI terms
Identifier:    http://stage.dublincore.org/usage/meetings/2007/08/singapore/.html/rdf-declaration-changes.html
Created:       2007-07-19

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2007-06-17 Tom Baker

The finalization of a new version of the DCMI Abstract Model
[1] and the development of a (not yet finalized) proposal
to add domain and range declarations to DCMI properties [2]
have consequences for how DCMI terms are declared in RDF and
documented in Web pages.

In the RDF declarations:

  1. Declarations such as 
        <dc:type rdf:resource="http://dublincore.org/usage/documents/principles/#vocabulary-term"/>
        <dc:type rdf:resource="http://dublincore.org/usage/documents/principles/#encoding-scheme"/>
        <dc:type rdf:resource="http://dublincore.org/usage/documents/principles/#encoding-scheme"/>
        <dc:type rdf:resource="http://dublincore.org/usage/documents/principles/#element-refinement"/>
     change to
        <rdf:type rdf:resource="http://www.w3.org/2000/01/rdf-schema#Class"/>
        <rdf:type rdf:resource="http://www.w3.org/2000/01/rdf-schema#Datatype"/>
        <rdf:type rdf:resource="http://purl.org/dc/dcam/VocabularyEncodingScheme"/>
        <rdf:type rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Property/>;
  
  2. If it is convenient, terms formerly declared in the XML style
        <dcterms:DCMIType      rdf:about="http://purl.org/dc/dcmitype/Event">
        <dcterms:DateScheme    rdf:about="http://purl.org/dc/terms/W3CDTF"> 
        <dcterms:SubjectScheme rdf:about="http://purl.org/dc/terms/LCSH"> 
        <rdf:Property          rdf:about="http://purl.org/dc/terms/bibliographicCitation">
     can be declared in the following style
        <rdf:Description rdf:about="http://purl.org/dc/dcmitype/Event"> 
        <rdf:Description rdf:about="http://purl.org/dc/terms/W3CDTF"> 
        <rdf:Description rdf:about="http://purl.org/dc/terms/LCSH"> 
        <rdf:Description rdf:about="http://purl.org/dc/terms/bibliographicCitation">
     because rdf:type is always specified (see point 1 above).
  
  3. Members of Vocabulary Encoding Schemes, such as members of the DCMI
     Type Vocabulary, will be declared with an additional statement:
        <dcam:memberOf rdf:resource="http://purl.org/dc/terms/DCMIType"/>
  
  4. Properties will have additional declarations of domains and ranges, e.g.:
        <rdfs:domain rdf:resource="http://example.org/dc/terms/BibliographicResource"/>
        <rdfs:range  rdf:resource="http://example.org/dc/terms/BibliographicReference"/>
  
  5. The Vocabulary Management Tool has hitherto supported
     the construction of classes such as
     DateScheme and FormatScheme, with URIs such as
     http://purl.org/dc/terms/DateScheme, in order to associate
     qualifiers (e.g., dcterms:W3CDTF) with terms qualified
     (in this case, dc:date).  See for example [6].  These constructs
     are no longer supported by the abstract model, so the routines 
     which create them should no longer be used.  On the whole, this
     should lead to a simplification of the VMT scripts.

In the XML data used as input to the VMT (e.g., [7]), there
will be several changes:

  1. <Qualifies> statements will be deleted from new versions
     of terms.  (These were used to create DateScheme, FormatScheme,
     etc.)
  
  2. <Type-of-Term> will be updated, as above.
  
  3. <Domain> and <Range> will be added.

The Web pages generated by the VMT will need to be updated:

  1. Show domains and ranges for properties.
  
  2. When Domain and Range classes are declared [2], the Web 
     document will need a new section for these.
  
Beyond the RDF issues, there are implications
for the DCMI Registry as well, as the registry has been
customized on the basis of the pre-DCAM2007 typology of
terms and their URIs (e.g., "encoding scheme" and [8]).

[1] http://dublincore.org/documents/2007/06/04/abstract-model/
[2] http://dublincore.org/documents/2007/02/05/domain-range/
[3] http://dublincore.org/2006/12/18/dcq.rdf
[5] http://purl.org/dc/terms/DateScheme
[7] http://dublincore.org/usage/xml/terms.xml
[8] http://dublincore.org/usage/documents/principles/#encoding-scheme