SKOS — Simple Knowledge Organization System
- data model for sharing and linking knowledge organization systems via the Web.
- porting existing knowledge organization systems to the Semantic Web.
- expresses catetory use case:
:Mammal skos:broader :Animal .
- not explicitly transitive
:Dawg skos:broader :Animal .
SKOS is not a formal knowledge representation language.
Use Case — Tentative Ontologies
- Proliferation of term sets with unstated (conflated) relationships.
- Given SNOMED-CT terms relationships
- :PulmonaryAdema < :RespiratoryIllness
- :Finger < :Hand
Equivalences
| concept | skos | rdfs |
|---|
| A is a refinement of B | <A> rdfs:subClassOf <B>. | <A> skos:narrowerThan <B>. |
| <A> rdfs:subPropertyOf <B>. |
| A uber alles | | <A> skos:TopLevelConcept <B>. |
MixIns
Using OWL and skos together:
ex:mammals skos:broader ex:animals .
ex:mammals rdfs:subClassOf ex:animals .
but ex:mammals is an instance (ex:mammals rdf:type skos:Concept .)
and the subject of rdfs:subClassOf is a class.
Does that break use cases?
Cost
- Have to re-invent a lot of tooling.
- Decidability profiles largely unknown.
Qualified Ontologies
Use RDFS/OWL, which humility.
Express reservations in your schema.
# Machine-imported SNOWMED Ontology.
# Intended Use: faceted browsing of patient afflictions.
# Not good for: infering classes of individuals -- concludes fatuous types.
# - ericP
:PulmonaryAdema rdfs:subClassOf :RespiratoryIllness . # machine-curated - not checked
:Finger rdfs:subClassOf :Hand . # machine-curated - not checked
Cost
- Have to vet applicability of ontology.
- Embarassing.
Evaluating
- Need to compare the use cases enabled by one approach vs. another.
- Need to abandon dignity.
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with attribution to W3C.