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[RDFa, ALL] Ranges of Dublin Core properties and RDFa

From: Thomas Baker <baker@sub.uni-goettingen.de>
Date: Mon, 26 Feb 2007 14:05:18 +0100
To: SWD Working Group <public-swd-wg@w3.org>
Message-ID: <20070226130517.GA2168@Octavius>

Ben, Mark, Michael,

In Section 3.2, the Primer [1] says:

    In the above markup and triples, as well as in the rest of
    the document, we slightly abuse the dc:creator  predicate,
    which is most often meant to refer to a person, not just
    a literal. 

Currently, dc:creator has no formal range, but DCMI is
considering a proposal to replicate the fifteen properties
of the http://purl.org/dc/elements/1.1/ namespace into the
http://purl.org/dc/terms/ namespace and assign ranges 
to these properties.  This proposal has been out for Public
Comment, which closes on March 5 (details below).

Assigning a range to dcterms:creator (proposed range: Agent) would
in no way break the examples in the Primer, which use dc:creator
(range undefined).  However, DCMI would encourage new implementations
of DC metadata to make use of the new dcterms: properties rather than
the older dc: properties.  Furthermore, as already discussed in the 
Public Comment period, the proposal to assign ranges
raises more general issues about the expected ranges of properties such
as dc:date and dc:creator [2,3].  It would be extremely if this 
group could provide input to DCMI on this issue - both in general and from
the standpoint of RDFa (for example, on the assumptions or preferences
reflected in the quote above).

Note that a number of other related specifications (especially
[4], Expressing Dublin Core metadata using RDF) are in the pipeline and 
depend for their finalization on the outcome of Public Comment on the 
Abstract Model.

Tom

[1] http://www.w3.org/2006/07/SWD/RDFa/primer/
[2] http://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0702&L=dc-architecture&P=4038
[3] http://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0702&L=dc-architecture&P=10112
[4] http://dublincore.org/documents/dc-rdf/


----

I would like to draw the attention of this group to a Public
Comment period, through 5 March, on a revised version of the
DCMI Abstract Model [1] and a proposed vocabulary of domains
and ranges for DCMI metadata terms [2].  

In particular Section 5, which specifies the relationship
of the DCMI Abstract Model to RDF [6], may be of interest.

Further context about this comment period is provided in
postings to the DC-ARCHITECTURE working group [3,4, see also
below], where any comments should be posted and discussion
is now taking place [5].

Tom Baker

[1] http://dublincore.org/documents/2007/02/05/abstract-model/
[2] http://dublincore.org/documents/2007/02/05/domain-range/
[3] http://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0702&L=dc-architecture&P=171
[4] http://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0702&L=dc-architecture&P=291
[5] http://www.jiscmail.ac.uk/lists/dc-architecture.html
[6] http://dublincore.org/documents/2007/02/05/abstract-model/#sect-5



> Date: Mon, 5 Feb 2007 18:32:28 +0100
> From: Thomas Baker <tbaker@tbaker.de>
> To: DCMI Architecture <dc-architecture@jiscmail.ac.uk>
> Subject: Public comment for revision of DCMI Abstract Model
> 
> The DCMI Abstract Model, which attained the status of DCMI
> Recommendation in March 2005, has been revised in light of
> discussion and feedback from the DCMI Architecture Working
> Group, the DCMI Usage Board, and the broader community.
> 
> This revised version of the Abstract Model [1] has been
> posted for a four-week public comment period.  The major
> differences between this revised version and the 2005 version
> [2] are summarized below.  A revised DCMI Namespace Policy
> [3] proposing a new DCMI namespace for Abstract Model entities
> has been posted for comment at the same time.
> 
> Interested members of the public are invited to post comments
> on these Proposed Recommendations to the DC-ARCHITECTURE
> mailing list [4], including "[DCAM Public Comment]" in the
> subject line. Public Comment will be open from 5 February
> through 5 March 2007.
> 
> [1] http://dublincore.org/documents/2007/02/05/abstract-model/
> [2] http://dublincore.org/documents/2005/03/07/abstract-model/
> [3] http://dublincore.org/documents/2007/02/05/dcmi-namespace/
> [4] http://www.jiscmail.ac.uk/lists/dc-architecture.html
> 
> 
> 
> 
> Changes in the DCMI Abstract Model, 2005 to 2007
> 
> --  Added a table explicitly mapping Abstract Model entities to
>     properties and classes of the Resource Description Framework
>     (RDF) and RDF Schema (RDFS).  The DCMI Abstract Model defines
>     a particular Description Model on the basis of RDFS semantics.
> 
> --  Added a separate Vocabulary Model specifying the types
>     of "terms" used in Dublin Core metadata descriptions and
>     including support for formal domains and ranges for properties.
>     The declaration of a vocabulary of classes and their use
>     as domains and ranges for DCMI properties is the focus of a
>     separate Public Comment period.
> 
> --  Changed the definition of 'vocabulary encoding scheme' --
>     defined in 2005 as "a class that indicates that the value of a
>     property is taken from a controlled vocabulary" -- to mean "an
>     enumerated set of resources" of which the value is a member.
>     (A value can be described as an instance of a class by other
>     means, such as by a separate statement to this effect).
> 
> --  Updated the definition of 'rich representation', adding
>     the notion of 'media type'.
> 
> Other editorial changes
> 
> --  Tightened the definition of 'syntax encoding scheme',
>     explicitly mapping the concept to the RDF Schema class
>     'Datatype'.
> 
> --  Tightened terminology and wordings to clarify meaning
>     (e.g., by consistently using phrases instead of sentences for
>     definitions; by referring to 'described resource' instead of
>     just 'resource'; by using the phrase "separate 'description'
>     about the 'value'" instead of a modeling entity for 'separate
>     description').
> 
> --  Shortened the document by removing sections describing
>     related issues such as 'dumb-down' (formerly Section 5),
>     'structured values' (formerly Appendix A), and specific
>     encoding guidelines (formerly Appendixes B, C, and D).
>     Much of this material will be provided in revised form in
>     more user-oriented documentation.
> 
> --  Added a table mapping current Abstract Model terminology
>     to the terminology in legacy DCMI "grammatical principles"
>     documentation (now Appendix A).
> 
> --  Permitted a value string to be associated with either
>     a language tag or syntax encoding scheme, or neither, but
>     not both.
> 
> --  Added a note to the effect that classes can be declared
>     explicitly or inferred from the domains and ranges of
>     properties.  Dropped the guideline that in DCMI metadata
>     descriptions, the class of the resource being described should
>     be indicated by the value of the Dublin Core Type property.
> 
> --  Simplified the Description Model, removing 'marked-up
>     text' and 'structured value string' as separate entities and
>     rearranging the diagram to improve readability.
> 
> --  Added placeholder URIs identifying DCMI Abstract Model
>     entities in a new DCMI namespace (as described in the 
>     revised DCMI Namespace Policy, also posted for Public
>     Comment).
> 
> --  Replaced QNames throughout the document with full URIs.
> 
> 
> 
> -- 
> Dr. Thomas Baker <tbaker@tbaker.de>
> Director, Specifications and Documentation
> Dublin Core Metadata Initiative
Received on Monday, 26 February 2007 13:02:25 GMT

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