Download - OpenHPI 5.5 - Web Ontology Language (Part 2)
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Dr. Harald Sack
Hasso Plattner Institute for IT Systems Engineering
University of Potsdam
Spring 2013
Semantic Web Technologies
Lecture 5: Knowledge Representations II05: Web Ontology Language - OWL (Part 2)
Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
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Lecture 5: Knowledge Representations II
Open HPI - Course: Semantic Web Technologies
Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
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05 Web Ontology Language - OWL (Part 2)Open HPI - Course: Semantic Web Technologies - Lecture 5: Knowledge Representations II
Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
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OWL – Classes, Properties and Individuals
• 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
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• there exist two predefined classes
• owl:Thing (class that contains all individuals)
• owl:Nothing (empty class)
• Definition of a class
:Wine a owl:Class .
OWL – Classes
⊤
⊥
• Definition of individuals via class membership
• Individuals can also be defined without direct class membership as named entity
Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
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:WegelerRheingauRiesling a :Wine .
OWL – Individuals
Wine(WegelerRheingauRiesling)
:HaraldSack a owl:NamedIndividual .
Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
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OWL – Properties
• there exist two variants:
• object properties
• datatype properties
• Object properties are defined like classes
• Domain and Range of object properties
:isMadeFrom a owl:ObjectProperty .
:isMadeOf a owl:ObjectProperty ; rdfs:domain :Wine ; rdfs:range :Grapes .
Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
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OWL – Object Properties
• Domain and Range of object properties
• in DL domain and range can be defined in the following way:
• Domain: ∃isMadeOf.⊤ ⊑ Wine
• Range: ⊤ ⊑ ∀isMadeOf.Grapes
:isMadeOf a owl:ObjectProperty ; rdfs:domain :Wine ; rdfs:range :Grapes .
Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
9• Datatype properties have datatypes as range
• Domain and range of datatype properties
• Many XML datatypes can be used.
:hasVintageYear a owl:DatatypeProperty .
OWL – Datatype Properties
:hasVintageYear a owl:DatatypeProperty ; rdfs:domain :Wine ; rdfs:range xsd:integer .
∃hasVintageYear.⊤ ⊑ Wine
⊤ ⊑ ∀hasVintageYear.Integer
Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
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OWL – Properties and Individuals
: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
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OWL – Properties and Individuals
• Properties in general are not functional
: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
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OWL – Class Hierarchies
• via inference it can be entailed that „Wine“ is also a subclass of „Beverage“
:Wine a owl:Class ; rdfs:subClassOf :AlcoholicBeverage .:AlcoholicBeverage a owl:Class ; rdfs:subClassOf :Beverage .:Beverage a owl:Class .
Wine ⊑ AlcoholicBeverageAlcoholicBeverage ⊑ Beverage
Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
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OWL – Class Hierarchies and Disjunctiveness
• via inference it can be entailed that „Wine“ and „Pizza“ are also disjoint classes.
: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 ⊑ AlcoholicBeveragePizza ⊑ MainDishAlcoholicBeverage ⊓ MainDish ⊑ ⊥
Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
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OWL – Class Hierarchies and Disjunctiveness
• 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
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OWL – Class Hierarchies and Equivalence
:AlcoholicBeverage a owl:Class .:Liquor a owl:Class .:Wine a owl:Class ; rdfs:subClassOf :AlcoholicBeverage .:AlcoholicBeverage owl:equivalentClass :Liquor .
• via inference it can be entailed that „Wine“ is also an „Liquor“
Wine ⊑ AlcoholicBeverageAlcoholicBeverage ≡ Liquor
Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
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06 Web Ontology Language - OWL (Part 3)Open HPI - Course: Semantic Web Technologies - Lecture 5: Knowledge Representations II