On Wed, May 29, 2002 at 12:54:55PM +0200, Roland Schwaenzl wrote:
> well...one better should look for
>
> http://www.mathematik.uni-osnabrueck.de/projects/dcqual/qual21.3.1/Schema/A/terms
I think you mean
http://www.mathematik.uni-osnabrueck.de/projects/dcqual/qual21.3.1/Schema/A/dcterms?
I see that this version does not include the RangeOf
construct, making it even closer to my text representation.
I also noticed a neat assertion in there I had missed before
(rdfs:label subPropertyOf dc:title).
> What is in there should suffice as support of the dc-web-site
> for RDF applications. That is for instance what an RDF Schema
> intended for.
Looking at the declaration of "dcterms:alternative" (where "---"/"+++"
indicates whether something is found in my text representation):
+++| <rdf:Property rdf:about="http://purl.org/dc/terms/alternative">
+++| <rdfs:label xml:lang="en">Alternative</rdfs:label>
+++| <rdfs:comment xml:lang="en">Any form of the title used as a substitute or
+++| alternative to the formal title of the resource.</rdfs:comment>
+++| <dc:description xml:lang="en">This qualifier can include Title
+++| abbreviations as well as translations.</dc:description>
+++| <rdfs:subPropertyOf rdf:resource="http://purl.org/dc/elements/1.1/title"/>
---| <rdfs:isDefinedBy rdf:resource="http://purl.org/dc/terms/"/>
+++| <dcterms:issued>2000-07-11</dcterms:issued>
| </rdf:Property>
(Note that I have expanded the namespace references.)
I find a few differences with respect to my text representation
(where "---"/"+++" indicates whether something is captured
by the RDF schema above):
---| VMS-ID: alternative-002
+++| Name: alternative
+++| URI: http://purl.org/dc/terms/alternative
+++| Label: Alternative
+++| Definition: Any form of the title used as a substitute or alternative
+++| to the formal title of the resource.
+++| Comment: This qualifier can include Title abbreviations as well
+++| as translations.
---| Term Type: http://dublincore.org/usage/documents/mission/#element-refinement
+++| subPropertyOf: http://purl.org/dc/elements/1.1/title
---| Decision: http://dublincore.org/usage/decisions/#2002.01
---| Date modified: 2002-06-15
+++| Date added: 2000-07-11
---| Supersedes: http://dublincore.org/usage/terms/dc/#alternative-001
---| Status: http://dublincore.org/usage/documents/process/#recommended
The RDFS representation lacks information on Status, Term Type,
and Versioning (VMS-ID, Decision, Date modified, Supersedes). If the
schema is sufficient as support for RDF applications, this means that
an RDF application would not need these things?
Regardless of the answer, I find myself puzzled by the
implications of one assertion in the RDF schema:
dcterms:alternative isDefinedBy http://purl.org/dc/terms/
According to http://www.w3.org/2000/01/rdf-schema,
"isDefinedBy" means "Indicates a resource containing and
defining the subject resource". I am confused because
I think of "alternative" as being uniquely _identified_
by the string http://purl.org/dc/terms/alternative but
actually _defined_ and documented in the Web resource
http://dublincore.org/usage/terms/dc/ (to be precise, at
http://dublincore.org/usage/terms/dc/#alternative-002).
> [This doesn't say, that all RDF applications will just use
> such a slim version. ]
I am assuming that one could declare the "missing" information
from my text description as RDF assertions as well...
> Your question about automatic generation:
>
> That may depend on the metadata/structure of the documents
> /usage/terms/dc/ cites.
>
> In case the snippets of information one wants to see in a
> Schema ready for machine consumption, which uses standardized
> vocabulary and formal syntax to express (semantic) relations
> and rules to machines can safely be picked up from documents
> intended for human consumption - of course you can write a
> program - but you're left to define (!), what will be mapped
> to what....i.e. and additional set of rules.
In that sense, a Perl script is (inherently) a set of
such rules? Making the text document safe for precisely
such conversion is what I would like to be able to do.
> For that it's a bit confusing, that usage/terms/dc/ mixes
> seemingly (?) existing metadata vocabulary with it's own terms
> - technically speaking it's not clear whether an additional
> namespace is asked for to represent the terms used in an
> RDF Schema.
Yes indeed. That's why I am making a point of inviting
comments on that attribute set now, before the concrete sets.
And I was always assuming that this vocabulary would itself
need to be declared (eg, "Decision").
> In the Scheme/A/terms approach things are expressed using DC
> and RDFS vocabulary only.
I'd be very happy to change the attributes to make the text
description more "plain vanilla" DC/RDFS. Suggestions most
welcome.
> One example: Speaking RDF usage/terms/dc seems to introduce
> a Class called "Decision" and goes ahead in typing certain
> documents as members of the Class. The pointer to such a
> document is an rdfs:seeAlso - In case one thinks it's important
> for the functionality of arbitrary RDF applications based
> on DC vocabulary to know about certain documents represent
> decisions - one will need a namespace outside the range of the
> dcmi namespace recommendation to host a Class named "Decision".
I'm not sure it is important as long as the RDF schema points
back to the "canonical" representation (assuming for the sake
of argument that it is http://dublincore.org/usage/terms/dc/).
For the sake of making the RDF schema more plain-vanilla
DC/RDFS, I'd be happy to see the link to a decision expressed
as an rdfs:seeAlso. I'm inclined to call it "Decision" in
the text document because the whole system is designed to
associate each change of version with exactly one uniquely
identified Decision.
> Similarly it is with the supersede property: Is it used -
> as one would expect - as a subProperty of dcterms:replaces
> or is it used to indicate versioning (of what)?
"Replaces" works just as well for me, especially since it
is defined as "The described resource supplants, displaces,
or supersedes the referenced resource". I do not recall
when or how I started using "Supersedes"... At any rate,
the use here is to indicate successive versions of a DCMI
Term Declarations -- in RDF terms, of the Property Declaration.
Many thanks,
Tom
--
Dr. Thomas Baker [log in to unmask]
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