Quick RDF Introduction Scott Streit

Terminology – RDF Triple (Also the triple form used in SPARQL) RDF Triple  (Resource, Property, RDFNode) Also shown as (subject, predicate, object)  Resource must be a URI (it is a subject and is always an ‘object property’ in the database)  Property is a link from the Resource to an RDFNode The Property belongs to the Resource and references the RDFNode Property is either a ‘standard’ RDF value or one defined by our ontology  RDFNode can be either A Resource (object property) A Literal (datatype property – sometimes referred to as a value)  (URI, URI, URI or Literal) RDF Serialization Forms  XML – a few ways to express triples  NTriples – Generally preferred short-hand method  N3 – one complete triple per line

Nodal View and Standard RDF Primitives Mammal Zebra Ontology (T-Box) Instances (A-Box) RDFS:subClassOf RDF:type RDF:label ‘Stripes’ KMDEV:Stripes KMDev:Location GeoLoc RDF:type 89N 84E … KMDEV:LL Zebra KMDev:LocType … …

Other Topics Reification – Knowledge about Knowledge RDF RDFS Famous Ontologies  Dublin Core (Metadata)  FOAF – Friend of a friend  vCard – Electronic Business Cards  SUMO, Dolce, CYC/UMBEL  Wordnet Semantics on the Internet  Twine – built on RDF  Google “Cancer” -> Searches related to Cancer  Wolfram Alpha  Evri SPARQL – Semantic Protocol and RDF Query Language

Other Details Ontology building tools  Jena – in code  Protégé  TopBraid Composer  Swoop, … Inference/reasoners  Proper subset is strongest capability  Closed world reasoning is not an option for most real problem spaces Datatype vs Object properties Domain and Range Sharing  RDF Dump  Linked Data  SPARQL Endpoint