Yes, I agree with this... though it's certainly not easy to come up with
the one paragraph summary of what DC is. That's one of our problems!
But talking about 'elements', 'simple' and 'qualified' doesn't help
much!
Here's my stab at a summary...
--- cut ---
Dublin Core (DC) is a metadata standard for describing a wide range of
digital, physical and conceptual resources (i.e. just about anything!).
A DC description is made up of a set of statements, each of which
comprises a property/value pair. Typically, the described resource is
identified using its URI and the value is either identified using its
URI or represented using a simple string (the 'value string'). In many
cases, multiple descriptions are combined in order to build up richer
descriptions ('description sets') about related groups of resources.
For example, in describing a digitised painting, it may also be
appropriate to describe the original painting from which the
digitisation was made and the original artist, thus creating a
description set of three related descriptions. Statements may be
refined by indicating the language of the value string, any data-type
('syntax encoding scheme') to which the value string conforms or the
class ('vocabulary encoding scheme') from which the value is taken.
Properties, syntax encoding schemes, vocabulary encoding schemes and
concepts in controlled vocabularies are known as 'terms'. All terms in
DC metadata are assigned URIs, and schema languages are used to indicate
the relationships between them.
The features of the DC metadata standard are fully described in the
Dublin Core Abstract Model (DCAM).
The Dublin Core Metadata Initiative (DCMI), the body that facilitates
the community development of the DC metadata standard, provides a core
set of about 80 properties, encoding schemes and controlled vocabularies
from which descriptions can be constructed, but encourages communities
to create additional terms as necessary, within the framework provided
by the DCAM.
Finally, the DCMI community has defined three encoding syntaxes that can
be used to encode DC metadata records for exchange between software
systems and services using XHTML, XML and RDF.
Historically, DC refered to properties as 'elements' and is perhaps best
known for the Dublin Core Metadata Element Set (DCMES) - a set of 15
elements, created originally to support the discovery of resources on
the Web.
--- cut ---
This, rightly(!), relegates DCMES to a footnote and doesn't even mention
simple and qualified! :-)
On the face of it, it may seem harder to grasp than the traditional
'element', DCMES, 'simple DC', 'qualified DC' approach - but I think
that is largely to do with where we come from. Personally, I think it
is much clearer - it emphasises what is important and ignores what can
safely be forgotten.
Andy
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Head of Development, Eduserv Foundation
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> -----Original Message-----
> From: A mailing list for the Dublin Core Metadata
> Initiative's Usage Board [mailto:[log in to unmask]] On
> Behalf Of Pete Johnston
> Sent: 21 March 2006 11:05
> To: [log in to unmask]
> Subject: Re: Updated Wikipedia article
>
> Diane I. Hillmann wrote:
> > Folks:
> >
> > I went in and changed the page:
> > http://en.wikipedia.org/wiki/Dublin_Core
> > using stuff from "Using Dublin Core" primarily.
> >
> > You're welcome to see what you think and do some editing
> yourself, if
> > you've a mind to do so. I won't take it personally, I promise!
>
> I haven't edited the document on Wikipedia (yet), and I don't
> really want to do so unilaterally, but (and this really
> applies to other introductory resources like the "Using
> Dublin Core" document and like the conference tutorials) I
> think that the role of the DCMI Abstract Model as providing
> the conceptual framework for DC should be presented more "up
> front" e.g. there should be a short/simplified summary
> description of the DCAM in the introductory section, or as a
> separate section following the intro and before the
> discussion of Simple DC and Qualified DC. Mentioning the DCAM
> _only_ as a tool for comparing different syntaxes is only
> telling half the story (IMHO) - though I think the DCAM doc
> itself might be slightly more "bullish" in its own intro
> paragraph! ;-).
>
> Now sure, I appreciate that that might look like a case of
> "historical revisionism" to the casual observer who knows
> "the 15 elements came first" (or indeed only knows the 15
> elements), but I do think we need to shift firmly towards
> putting the DCAM at the centre of our explanations of "what
> DC is". (If people want a history of the evolution of DC, and
> how DCMI got from "the 15 elements" to "the qualifiers" to
> the grammatical principles to the DCAM, OK, that's fine, but
> that's a different document.)
>
> I recognise this probably goes against the way we've tended
> to introduce DC, but I'd go as far as saying that it is
> confusing/unhelpful to start talking about "elements" without
> first describing the DCAM, at least in some way - maybe not
> every fine detail, but the fundamental points about making
> statements that assert relationships between resources and
> values. Without such "contextual" information, it just begs
> the question of what an "element" is. It makes a "leap of
> faith" that readers already share a common understanding of
> what an element is, but (as we've found out somewhat
> painfully over the last few years), that is not the case:
> the term "element" is used to refer to different things in
> different contexts and readers draw their own (different,
> incompatible) conclusions ("Ah, they're talking about XML
> elements", "Ah, so they're referring to things like LOM
> elements", "Ah, they mean attribute-value pairs" etc etc etc).
>
> I think the account of "Simple Dublin Core" also blurs the
> distinction between the DCMES as a set of terms, each of
> which may be deployed in many different "DC application
> profiles" with different constraints on their usage in a
> description set, and "Simple Dublin Core" as one such DCAP
> with one particular set of constraints. And in the account of
> "Qualified DC" I'm not sure the word "value" is being used in
> the way it is used in the DCAM. I think phrases like "the
> value may still be useful to a human reader" suggest that the
> reference is to (what the DCAM
> calls) "value strings".
>
> Pete
>
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