Netting more MARC fruit discussed the use of the rdfs:subPropertyOf property to allow MARC21 data to interoperate with triples based on similar properties in element sets from other metadata schemas. We can show the procedure in action using the Target audience property described in Getting to higher MARC branches.

A quick examination of the namespaces for Dublin Core terms, the FRBR entity-relationship model, ISBD, and RDA reveals properties for intended or target audience in each. The FRSAD (FR for Subject Authority Data) namespace also has a property labelled “has audience”, but it refers to the class Nomen which contains labels and identifiers for subject topics; it is about subject headings and classifications, not the resource itself, so has a completely different context and is not suitable for interoperating with MARC21′s Target audience data.

The relevant triples for each property are:

Dublin Core terms:

@prefix dct: <http://purl.org/dc/terms/>.
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>.
dct:audience rdfs:comment "A class of entity for whom the resource is intended or useful." .
dct:audience rdfs:label "audience" .
dct:audience rdfs:range dct:AgentClass .

FRBR:

@prefix frbrer: <http://iflastandards.info/ns/fr/frbr/frbrer/>.
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#&gt.
@prefix skos: <http://www.w3.org/2004/02/skos/core#>.
frbrer:P3006 skos:definition "Relates a work to the class of user for which the work is intended, as defined by age group, educational level, or other categorization." .
frbrer:P3006 rdfs:label "has intended audience" .
frbrer:P3006 rdfs:domain frbrer:C1001 .

ISBD:

@prefix isbd: <http://iflastandards.info/ns/isbd/elements/>.
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#&gt.
@prefix skos: <http://www.w3.org/2004/02/skos/core#&gt.
isbd:P1091 skos:definition "Relates a resource to a note providing non-evaluative information as to the potential or recommended use of the resource and/or the intended audience." .
isbd:P1091 rdfs:label "has note on use or audience" .
isbd:P1091 rdfs:domain isbd:Resource .

RDA:

@prefix rda: <http://rdvocab.info/Elements/>.
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#&gt.
@prefix skos: <http://www.w3.org/2004/02/skos/core#&gt.
@prefix unc: <http://.../>.
rda:intendedAudienceWork skos:definition "The class of user for which the content of a resource is intended, or for whom the content is considered suitable, as defined by age group (e.g., children, young adults, adults, etc.), educational level (e.g., primary, secondary, etc.), type of disability, or other categorization." .
rda:intendedAudienceWork rdfs:label "Intended audience (Work)" .
rda:intendedAudienceWork rdfs:domain rdafrbr:Work .
rda:intendedAudienceWork rdfs:subPropertyOf unc:intendedAudience .

Unconstrained RDA:

@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#&gt.
@prefix skos: <http://www.w3.org/2004/02/skos/core#&gt.
@prefix unc: <http://.../>.
unc:intendedAudience skos:definition "The class of user for which the content of a resource is intended, or for whom the content is considered suitable, as defined by age group (e.g., children, young adults, adults, etc.), educational level (e.g., primary, secondary, etc.), type of disability, or other categorization." .
unc:intendedAudience rdfs:label "Intended audience" .

And for our high-level MARC21 property:

@prefix m21plus: <http://marc21rdf.info/elements/.../>.
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#&gt.
@prefix skos: <http://www.w3.org/2004/02/skos/core#&gt.
m21plus:M00Aud skos:definition "The intellectual level of the target audience for which the material is intended." .
m21plus:M00Aud rdfs:label "Target audience" .

The MARC21 property has a narrower definition than any of the others. Taking into account the domain and range constraints leaves only the unconstrained RDA property as a candidate super-property:

m21plus:M00Aud rdfs:subPropertyOf unc:intendedAudience .

This allows triples from MARC21 records to have entailments which use the same unconstrained property as triples from RDA records; the FRBR-constrained RDA property is already a sub-property of the unconstrained property.

RDF graphs of MARC21 and RDA data triples and entailments.

RDF graphs of MARC21 and RDA data triples and entailments.

Of course, the original MARC21 triple is itself an entailment from a level 0 triple.

We can use the same procedure to align and map the other properties we found for target or intended audience. The resulting RDF ontology is:

@prefix dct: <http://purl.org/dc/terms/>.
@prefix frbrer: <http://iflastandards.info/ns/fr/frbr/frbrer/>.
@prefix isbd: <http://iflastandards.info/ns/isbd/elements/>.
@prefix m21plus: <http://marc21rdf.info/elements/.../>.
@prefix rda: <http://rdvocab.info/Elements/>.
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>.
@prefix unc: <http://.../>.
dct:audience rdfs:subPropertyOf unc:intendedAudience .
frbrer:P3006 rdfs:subPropertyOf unc:intendedAudience .
m21plus:M00Aud rdfs:subPropertyOf unc:intendedAudience .
rda:intendedAudienceWork rdfs:subPropertyOf unc:intendedAudience .
unc:intendedAudience rdfs:subPropertyOf unc:P1091 .
isbd:P1091 rdfs:subPropertyOf unc:P1091 .

Note that the ISBD property is broader in definition that the unconstrained RDA property, but is itself constrained by its domain. So we need an unconstrained version of the ISBD property, which has the broadest semantic of all the related properties.

RDF graph of Target/intended audience ontology

RDF graph of Target/intended audience ontology

This ontology allows all the data about the intended audience of a resource to be available as a single, common attribute; our MARC fruit is added to the basket automatically, once it has been plucked as a level 0 triple.

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By Gordon Dunsire, April 23, 2012, 4:14 pm (UTC-5)

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