Ontology Alignment Evaluation Initiative

A note about translation from SKOS to OWL

Ontology matchers tend to require ontologies to be matched (this is the least). Yet SKOS thesauri are not really ontologies. So people may want to translate SKOS thesauri into OWL ontologies. We are aware of at least two ways to achieve this.

Use the converted ontologies provided for the food, environment and library test sets. According to the description provided by Antoine Issac, they obey the following rules:

• instances of skos:Concept are converted into instances of owl:Class;
• skos:prefLabel, skos:altLabel and skos:hiddenLabel statements are converted to rdfs:label statements, which removes the subtle distinctions that exist between these different properties (in GTT for instance, many altLabels are not synonyms at all);
• various kind of skos:notes are converted to rdfs:comments;
• skos:broader statements are converted into rdfs:subClassOf statements;
• skos:related statements are converted into rdfs:seeAlso statements.

Use the tool developed by Miklos Nagy for the same purpose. It uses the following set of rules (see also Miklos provided short description):

• skos:Concept -> owl:Class
• skos:prefLabel -> rdfs:label
• skos:altLabel -> rdfs:label
• skos:broader -> rdfs:subClassOf
• skos:definition -> rdfs:comment
• skos:scopeNote -> rdfs:comment

Antoine also plan to evaluate returned alignment with "OWL relationships". The following interpretations will be made of OWL data sent back by participants:

• instances of owl:Class will be interpreted as instances of skos:Concept;
• owl:equivalentClass statements will be interpreted as skosm:exactMatch statements;
• if participants align the original concepts (as instances of skos:Concept and not owl:Class) using owl:sameAs, these statements will also be interpreted as skosm:exactMatchs;
• rdfs:subClassOf statements will be interpreted as skosm:broaderMatch statements;
• rdfs:seeAlso statements will be interpreted as stitchm:relatedMatch statements;
• if participants' tools output alignments involving defined classes using owl:intersectionOf and owl:unionOf respectively, the concerned statements will be interpreted as statements involving skosm:AND and skosm:OR. Disjunction-like statements (owl:disjoint, owl:differentFrom, owl:disjointWith, owl:ComplementOf which could be interpreted as statements involving skosm:NOT) will be ignored, as these are not evaluated.