OpenHPI 5.5 - Web Ontology Language (Part 2)

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OpenHPI 5.5 - Web Ontology Language (Part 2)

  1. 1. Semantic Web TechnologiesLecture 5: Knowledge Representations II 05: Web Ontology Language - OWL (Part 2) Dr. Harald Sack Hasso Plattner Institute for IT Systems Engineering University of Potsdam Spring 2013 This file is licensed under the Creative Commons Attribution-NonCommercial 3.0 (CC BY-NC 3.0)
  2. 2. 2 Lecture 5: Knowledge Representations II Open HPI - Course: Semantic Web Technologies Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  3. 3. 3 05 Web Ontology Language - OWL (Part 2)Open HPI - Course: SemanticHarald Sack, Hasso-Plattner-Institut, Universität Potsdam Semantic Web Technologies , Dr. Web Technologies - Lecture 5: Knowledge Representations II
  4. 4. OWL – Classes, Properties and Individuals4 • Ontology axioms consist of the following three building blocks: • Classes •comparable with classes in RDFS • Individuals •comparable with objects in RDFS • Properties •comparable with properties in RDFS Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  5. 5. OWL – Classes • there exist two predefined classes5 • owl:Thing (class that contains all individuals) ⊤ • owl:Nothing (empty class) ⊥ • Definition of a class :Wine a owl:Class . Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  6. 6. OWL – Individuals6 • Definition of individuals via class membership :WegelerRheingauRiesling a :Wine . Wine(WegelerRheingauRiesling) • Individuals can also be defined without direct class membership as named entity :HaraldSack a owl:NamedIndividual . Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  7. 7. OWL – Properties7 • there exist two variants: • object properties • datatype properties • Object properties are defined like classes :isMadeFrom a owl:ObjectProperty . • Domain and Range of object properties :isMadeOf a owl:ObjectProperty ; rdfs:domain :Wine ; rdfs:range :Grapes . Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  8. 8. OWL – Object Properties8 • Domain and Range of object properties :isMadeOf a owl:ObjectProperty ; rdfs:domain :Wine ; rdfs:range :Grapes . • in DL domain and range can be defined in the following way: • Domain: ∃isMadeOf.⊤ ⊑ Wine • Range: ⊤ ⊑ ∀isMadeOf.Grapes Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  9. 9. OWL – Datatype Properties • Datatype properties have datatypes as range9 :hasVintageYear a owl:DatatypeProperty . • Domain and range of datatype properties :hasVintageYear a owl:DatatypeProperty ; rdfs:domain :Wine ; rdfs:range xsd:integer . • Many XML datatypes can be used. ∃hasVintageYear.⊤ ⊑ Wine ⊤ ⊑ ∀hasVintageYear.Integer Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  10. 10. OWL – Properties and Individuals10 :Wine a owl:Class . :Grapes a owl:Class . :Riesling a :Grapes . :isMadeOf a owl:ObjectProperty ; rdfs:domain :Wine ; rdfs:range :Grapes . :hasVintageYear a owl:DatatypeProperty ; rdfs:domain :Wine ; rdfs:range xsd:integer . :hasQuality a owl:DatatypeProperty ; rdfs:domain :Wine ; rdfs:range xsd:string . :WegelerRheingauRiesling a :Wine ; :isMadeOf :Riesling ; :hasQuality “Spätlese“ . Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  11. 11. OWL – Properties and Individuals • Properties in general are not functional11 :Tempranillo a :Grapes . :Garnacha a :Grapes . :Mazuelo a :Grapes . :Graciano a :Grapes . :MarquesDeRiscal a :Wine ; :isMadeOf :Tempranillo ; :isMadeOf :Garnacha ; :isMadeOf :Mazuelo ; :isMadeOf :Graciano . Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  12. 12. OWL – Class Hierarchies12 :Wine a owl:Class ; rdfs:subClassOf :AlcoholicBeverage . :AlcoholicBeverage a owl:Class ; rdfs:subClassOf :Beverage . :Beverage a owl:Class . Wine ⊑ AlcoholicBeverage AlcoholicBeverage ⊑ Beverage • via inference it can be entailed that „Wine“ is also a subclass of „Beverage“ Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  13. 13. OWL – Class Hierarchies and Disjunctiveness13 :AlcoholicBeverage a owl:Class . :MainDish a owl:Class . :Wine a owl:Class ; rdfs:subClassOf :AlcoholicBeverage . :Pizza a owl:Class ; rdfs:subClassOf :MainDish . :AlcoholicBeverage owl:disjointWith :MainDish . Wine ⊑ AlcoholicBeverage Pizza ⊑ MainDish AlcoholicBeverage ⊓ MainDish ⊑ ⊥ • via inference it can be entailed that „Wine“ and „Pizza“ are also disjoint classes. Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  14. 14. OWL – Class Hierarchies and Disjunctiveness14 • OWL provides a shortcut to define several classes to be disjunctive [] a owl:AllDisjointClasses ; owl:members ( :Wine :Beer :SoftDrink :Vegetables :Seafood :Meat ) . Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  15. 15. OWL – Class Hierarchies and Equivalence15 :AlcoholicBeverage a owl:Class . :Liquor a owl:Class . :Wine a owl:Class ; rdfs:subClassOf :AlcoholicBeverage . :AlcoholicBeverage owl:equivalentClass :Liquor . Wine ⊑ AlcoholicBeverage AlcoholicBeverage ≡ Liquor • via inference it can be entailed that „Wine“ is also an „Liquor“ Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  16. 16. 16 06 Web Ontology Language - OWL (Part 3)Open HPI - Course: SemanticHarald Sack, Hasso-Plattner-Institut, Universität Potsdam Semantic Web Technologies , Dr. Web Technologies - Lecture 5: Knowledge Representations II

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