Hi,
I have a few comments regarding the recent DCMI publication titled
"Expressing Qualified Dublin Core in RDF / XML".
I wasn't sure the proper channels by which to send these comments,
so if there is a better forum for such issues, please feel free to
forward this there (and please let me know what that forum is).
Firstly, I was very pleased to see the publication of this document,
and the use of RDF/RDFS mechanisms for relating qualified properties
to core properties. All in all, I think it is a landmark publication
for the DCMI and I feel it will be of widespread benefit to several
communities now employing or planning/wishing to employ the DC ontology.
I am, however, concerned with the apparent promotion of what you call
the "poor man's structured value construction" for values which are
members of standardized, explicit enumerations. I understand how
difficult it is to craft good examples that illustrate a particular
concept or methodology, and don't fault the publication for the
particular examples, per se, but I percieve a danger of readers
following the examples as specific suggested practices, and this will
result in a horrendous explosion of needlessly redundant subgraphs.
A case in point: the use of anonymous nodes specified for rdf:type,
rdf:label, and rdf:value as the value of the dc:language property. If
such a practice were taken in contexts where language is defined for
billions of resources one will have an untenable proliferation of
redundant sub-graphs. Furthermore, it prohibits the ability to define
language specific labels for actual language values, limiting the
utility of such knowledge as-is for presentation to humans.
In addition, one must employ custom mechanisms outside the scope of
RDF and RDFS to ensure validity of labels and values, or to employ
alternate human-presentable labels for different contexts or locales,
which puts undue burden on applications processing that metadata.
In cases such as e.g. standard defined language values, one should
utilize an explicit RDF resource representing each language, for
which is defined resource specific properties only once, and other
properties such as dc:language should refer to the explicit resource
only.
Note that this is only one example of the inappropriateness of this
approach for certain types of property values, though it should be
sufficient to illustrate the issue of my concern.
I'm sure that all of the above is fully appreciated by the authors
of, and contributors to, this document. I simply wished to suggest that,
as many people will likely follow the examples detailed in the document
exactly, as a form of standard practice, it would IMO be wise to address
this issue of the risk of prolific redundancy when the "poor man's
construction" is employed, and recommend that it's use be limited to
cases where an explicit resource cannot be defined explicitly and
referenced by URI as a property value.
The world, I am sure, will thank you for it. I certainly will ;-)
Best Regards,
Patrick
--
Patrick Stickler Phone: +358 3 356 0209
Senior Research Scientist Mobile: +358 50 483 9453
Software Technology Laboratory Fax: +358 7180 35409
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