This file is licensed under the Creative Commons Attribution-NonCommercial 3.0 (CC BY-NC 3.0) Knowledge Engineering with Semantic Web Technologies Lecture 2: RDF Based Knowledge Representation 2.2 Model Building with RDFS Dr. Harald Sack Hasso-Plattner-Institut for IT Systems Engineering University of Potsdam Autumn 2015 Semantic Web Technologies , Dr. Harald Sack, Hasso Plattner Institute, University of Potsdam org/resource/Clyde_Tombaugh Where does the intended meaning really come from? Semantic Web Technologies . What does it really mean? http://dbpedia. Dr.org/ontology/discoverer http://dbpedia.org/property/satelliteOf http://dbpedia. Hasso Plattner Institute.org/resource/Pluto http://dbpedia.org/resource/Charon_(moon) http://dbpedia. University of Potsdam . Harald Sack. org/resource/Pluto http://dbpedia.org/resource/Pluto http://dbpedia. University of Potsdam . What does it really mean? http://dbpedia.org/resource/Charon_(moon) something which can be uniquely identified via the URI something which can be uniquely identified via the URI http://dbpedia.org/resource/Q141 We need more semantic expressivity..org/property/Q144 http://dbpedia. Hasso Plattner Institute.org/resource/Charon_(moon) but the URI for the same resource could also be but the URI for the same resource could also be http://dbpedia. Semantic Web Technologies .. Dr.org/property/satelliteOf http://dbpedia. Harald Sack.org/resource/Q142 http://dbpedia. Harald Sack. University of Potsdam . Dr. RDF Schema Semantic Web Technologies . Hasso Plattner Institute. w3. University of Potsdam .w3. @prefix rdf: <http://www. RDF Schema ● RDF Schema. @prefix rdfs: <http://www.org/2000/01/rdf-schema#> . Semantic Web Technologies .org/1999/02/22-rdf-syntax-ns#> . Harald Sack. :Earth rdf:type :Planet . officially called “RDF Vocabulary Description Language” ● RDF Schema allows: ○ Definition of classes via rdfs:Class ○ Class instantiation in RDF via rdf:type ○ Example: :Planet rdf:type rdfs:Class . Hasso Plattner Institute. Dr. @prefix : <http://example.org/Space#> . :satelliteOf rdf:type rdf:Property . University of Potsdam . Hasso Plattner Institute. RDF Schema ● Definition of properties via rdf:Property ● Definition of property restrictions on domain and range via rdfs:domain and rdfs:range ● Example :CelestialBody rdf:type rdfs:Class . Dr. Harald Sack. :satelliteOf rdfs:domain :CelestialBody . Semantic Web Technologies . :satelliteOf rdfs:range :CelestialBody . RDF Schema ● Everything in the RDF model is a resource ○ rdfs:Class rdf:type rdfs:Resource . ○ rdfs:XMLLiteral rdf:type rdfs:Resource . ○ rdfs:Literal rdf:type rdfs:Resource . University of Potsdam . ○ rdfs:ContainerMembershipProperty rdf:type rdfs:Resource . Hasso Plattner Institute. ○ rdfs:Container rdf:type rdfs:Resource . ○ rdfs:Datatype rdf:type rdfs:Resource . Harald Sack. ○ rdf:Property rdf:type rdfs:Resource . Dr. Semantic Web Technologies . RDF Schema ● Definition of hierarchical relationships: ○ Subclasses and superclasses via rdfs:subClassOf ○ Example: :Planet rdfs:subClassOf :CelestialBody . Dr. Semantic Web Technologies . Hasso Plattner Institute. ○ Subproperties and superproperties via subPropertyOf ○ Example :artificialSatelliteOf rdfs:subPropertyOf :satelliteOf . Harald Sack. University of Potsdam . Hasso Plattner Institute. Dr. University of Potsdam . RDFS Language Model rdfs:Class rdfs:Resource rdfs:Literal rdfs:Datatype rdf:Property rdf:type rdfs:comment rdfs:range rdf:XMLLiteral rdfs:subClassOf rdfs:domain ● instance relation rdfs:subPropertyOf ● subclass relation http://www.w3.org/TR/rdf-schema/#ch_classes Semantic Web Technologies . Harald Sack. defines the relation of a resource to its definition ○ rdfs:comment comment. Hasso Plattner Institute. Dr. usually as text ○ rdfs:label „readable“ name of a resource (contrary to ID) ○ rdfs:member super-property of all the container membership properties (e.g. RDF Schema ● Some more properties: ○ rdfs:seeAlso defines a relation of a resource to another. University of Potsdam . Harald Sack. rdf:_1. which explains it ○ rdfs:isDefinedBy subproperty of rdfs:seeAlso. …) Semantic Web Technologies . @prefix : <http://example.w3.org/2000/01/rdf-schema#> . Instance Definitions :Sputnik1 rdf:type :ArtificialSatellite . Harald Sack. :satelliteOf :Earth .w3.org/1999/02/22-rdf-syntax-ns#> .org/Space#> . RDFS Example @prefix rdfs: <http://www. rdfs:label “Sputnik 1”@en . :Planet rdf:type rdfs:Class . Dr. :Satellite rdf:type rdfs:Class . :Earth rdf:type :Planet . University of Potsdam . Hasso Plattner Institute. :satelliteOf rdfs:domain :CelestialBody . :satelliteOf :Earth . @prefix rdf: <http://www. :Moon rdf:type :Satellite . rdfs:comment “the first artificial Earth satellite in 1957” . Property Definitions :satelliteOf rdfs:range :CelestialBody . Class Definitions rdfs:subClassOf :CelestialBody . Semantic Web Technologies . :ArtificialSatellite rdf:type rdfs:Class . :satelliteOf rdf:type rdf:Property . rdfs:subClassOf :Satellite . rdfs:subClassOf :CelestialBody . University of Potsdam .Course Knowledge Engineering with Semantic Web Technologies Lecture 2: RDF Based Knowledge Representation Semantic Web Technologies . Hasso Plattner Institute.Logical Inference with RDFS OpenHPI . Harald Sack. Next: 03 . Dr.