SKOS and MeSH qualifiers

SKOS was brought to my attention yesterday, and I've been looking at
it in relation to the controlled vocabulary with which I have the most
experience, namely MeSH (Medical Subject Headings). For the most part it is
immediately evident how to represent MeSH using SKOS, but one aspect of MeSH,
qualifiers, makes me want to use SKOS differently that what appears right at
first glance. For anyone not familiar with MeSH, here is a brief description
of MeSH qualifiers from the MeSH site (http://www.nlm.nig.gov/mesh/):

  "There are 83 topical qualifiers used for indexing and cataloging in
  conjunction with descriptors. Qualifiers afford a convenient means of
  grouping together those citations which are concerned with a particular
  aspect of a subject."

MeSH descriptors are the main concepts in MeSH, and when searching with MeSH
one usually selects a descriptor and may restrict the search using one or more
of the qualifiers that are allowed for that descriptor.

The most obvious way I could see to represent qualifiers using SKOS would be
to use collections, with each descriptor that allows a particular qualifier
as a member of that collection. So for the qualifiers 'standards' and
'administration & dosage', and the descriptor 'Calcimycin':

<skos:Concept rdf:about="http://www.nlm.nig.gov/mesh/descriptors#Calcimycin">
	<skos:prefLabel>Calcimycin</skos:prefLabel>
</skos:Concept>

<skos:Collection>
	<rdfs:label>standards</rdfs:label>
	<skos:member rdf:resource="http://www.nlm.nig.gov/mesh/descriptors#Calcimycin" />
	<!-- other descriptors that allow the qualifier 'standards' -->
</skos:Collection>

<skos:Collection>
	<rdfs:label>administration &amp; dosage</rdfs:label>
	<skos:member rdf:resource="http://www.nlm.nig.gov/mesh/descriptors#Calcimycin" />
	<!-- other descriptors that allow the qualifier 'administration & dosage' -->
</skos:Collection>

What I was wondering is whether it would be possible to represent that same
relationship inversely. That is, not to list the members of the qualifier
collections within the skos:Collection element, but rather to list, within
a descriptor's skos:Concept element, which collections that descriptor is
a member of (note the use of the imaginary element skos:isMemberOf):

<skos:Concept rdf:about="http://www.nlm.nig.gov/mesh/descriptors#Calcimycin">
    <skos:prefLabel>Calcimycin</skos:prefLabel>
	<skos:isMemberOf rdf:resource="http://www.nlm.nig.gov/mesh/qualifiers#standards" />
	<skos:isMemberOf rdf:resource="http://www.nlm.nig.gov/mesh/qualifiers#administration%20&%20dosage" />
</skos:Concept>

<skos:Concept rdf:about="http://www.nlm.nig.gov/mesh/qualifiers#standards">
	<skos:Collection>
		<rdfs:label>standards</rdfs:label>
	</skos:Collection>
</skos:Collection>

<skos:Concept rdf:about="http://www.nlm.nig.gov/mesh/qualifiers#administration%20&%20dosage">
	<skos:Collection>
		<rdfs:label>administration &amp; dosage</rdfs:label>
	</skos:Collection>
</skos:Collection>

This is more in line with the way MeSH is described with its own DTDs, where
each descriptor has a list of allowed qualifiers. Of course the idea is not
to try to bend SKOS every which way so that it looks like MeSH, but this could
be a useful construct for other controlled vocabularies.

Comments? (Flames?)
-- Robert

--------------------
Robert Watkins
rwatkins@foo-bar.org
--------------------

Received on Friday, 8 July 2005 13:53:56 UTC