Ontologies
Ontologies are semantic models in Semantic Web
- an ontology is some knowledge about concepts of some domain and the relations between them
- or, an ontology is a formal description that provides a user some (shared) understanding about a domain
Ontologies for Semantic Web:
- should be understandable by machines
- should allow reasoning
- RDFS + OWL for describing ontologies on top of RDF graphs
- Tbox in Descriptive Logic as the formal foundation for inferencing
- in OWL there's a special property:
SOME_URI a owl:Ontology
Useful for
Types:
- upper ontologies - general things in abstract manner
- domain ontologies
- lightweight ontologies for web
Popular Ontologies
FOAF
FOAF - friend of a friend (uses RDFS-Plus)
- a format for describing people and their relationships
- also, about organizations
SKOS
SKOS (uses RDFS-Plus)
- Simple Knowledge Organization System
- e.g. controlled vocabularies, taxonomies, thesauri - defines relationships between terms
- in a distributed and linkable way
Others
- GR: Good Relations - for business to make descriptions of their offers (uses OWL)
- QUDT - Quantity/Units/Dimensions/Types - for aligning data coming from multiple source (uses OWL)
See Also
Sources