Linked Data Semantic Repository: Ontologies

Except for datasets, Linked Data Semantic Repository (LDSR) includes also ontologies and schemata. This ensures the connectivity of the data.

LDSR contains the following ontologies:

• Dublin Core (DC) - a relatively small but very popular metadata schema. It defines 15 attributes (e.g. author/contributor, date of publication, language, etc.) that can be used to describe information resources;
• SKOS (Simple Knowledge Organization System) - a relatively simple RDF schema that allows describing taxonomies of concepts. The most important properties in SKOS are skos:broader and skos:narower, defined as inverse of each other. The subsumption semantics of these relationships is very appropriate for the encoding of topic ontologies and subjects classifiers.
• RSS - an RDF schema designed to enable syndication of machine-readable information about updates from web sites
• FOAF - a project aimed at creating a network of machine-readable personal profiles published on the Web. FOAF ontology defines the attributes of personal profiles, which allows for publication of contact information and links to other profiles.

We had to modify the FOAF schema in LDSR, removing the declaration that foaf:homepage is an inverse functional property, because in some of the data sets, different entities were defined to have the same home page, which was resulting in inference of faulty owl:sameAs equivalences. We had to fix in the same way also foaf:primaryTopic and foaf:isPrimaryTopicOf.