I have two questions regarding methods for representing dcq encoding
information within rdf as outlined by May 3rd 2001 draft of "Expressing
Qualified Dublin Core in RDF"
(http://www.mathematik.uni-osnabrueck.de/projects/dcqual/qual21.3.1/).
Question 1. Wouldn't it be more appropriate to see dcq objects as
specialized versions of rdf objects rather than as exact equivalents of rdf
objects? Thus wouldn't it be better to say:
<?xml version="1.0"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:dcq="http://dublincore.org/2000/03/13/dcq#">
<rdf:Description>
<dc:subject rdf:parseType="Resource">
<dcq:encoding rdf:resource="http://dublincore.org/2000/03/13/dcq#MESH"
/>
<rdf:value>D08.586.682.075.400</rdf:value>
<rdfs:label>Formate Dehydrogenase</rdfs:label>
</dc:subject>
</rdf:Description>
</rdf:RDF>
where dcq:encoding has been declared a subproperty of rdf:type, e.g.:
<rdf:Property rdf:about="http://dublincore.org/2000/03/13-dcq#encoding">
<rdfs:label>Encoding</rdfs:label>
<rdfs:comment>Describes Qualified Dublin Core Encoding Class
used.</rdfs:comment>
<rdfs:subPropertyOf
rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#type" />
<rdfs:isDefinedBy rdf:resource="http://dublincore.org/2000/03/13-dcq#" />
</rdf:Property>
This allows dcq:encoding to be a specialized form of rdf:type -- with all
the meaing of rdf:type PLUS additional specialized characteristics --
rather than simply an exact equivalent of rdf:type. It would facilitate
local community extension of dcq semantics which is allowed (or encouraged
depending on how you read the current spec), since it would enable local
communities to create additional semantics in their namespaces designed to
be used as specific class values under dcq:encoding (rather than simply as
instances of more generic rdf:type class values).
Question 2. Regardless of the answer to 1, there are multiple, seemingly
rdf-equivalent ways to represent dcq encoding information. E.g.:
Representation A (from the current draft):
<?xml version="1.0"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:dcq="http://dublincore.org/2000/03/13/dcq#">
<rdf:Description>
<dc:subject>
<dcq:MESH>
<rdf:value>D08.586.682.075.400</rdf:value>
<rdfs:label>Formate Dehydrogenase</rdfs:label>
</dcq:MESH>
</dc:subject>
</rdf:Description>
</rdf:RDF>
Representation B:
<?xml version="1.0"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:dcq="http://dublincore.org/2000/03/13/dcq#">
<rdf:Description>
<dc:subject rdf:parseType="Resource">
<rdf:type rdf:resource="http://dublincore.org/2000/03/13/dcq:MESH" />
<rdf:value>D08.586.682.075.400</rdf:value>
<rdfs:label>Formate Dehydrogenase</rdfs:label>
</dc:subject>
</rdf:Description>
</rdf:RDF>
Representation C:
<?xml version="1.0"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:dcq="http://dublincore.org/2000/03/13/dcq#">
<rdf:Description>
<dc:subject rdf:parseType="Resource">
<rdf:type>http://dublincore.org/2000/03/13/dcq:MESH</rdf:type>
<rdf:value>D08.586.682.075.400</rdf:value>
<rdfs:label>Formate Dehydrogenase</rdfs:label>
</dc:subject>
</rdf:Description>
</rdf:RDF>
All 3 representations generate the identical 4 triples, and all 3
representations graph the same way (at least according to SiRPAC). From
both an rdf-community perspective, and also from a DCMI-community
perspective, is there any reason to prefer one representation over the
others? (If so, which and why?)
My apologies if these questions have been asked before or are overly naive.
Timothy W. Cole
University Library
University of Illinois at Urbana-Champaign
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