OpenHPI 5.4 - Web Ontology Language

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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 II04: Web Ontology Language - OWL

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


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04 Web Ontology Language - OWLOpen HPI - Course: Semantic Web Technologies - Lecture 5: Knowledge Representations II

Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamTurmbau zu Babel, Pieter Brueghel, 1563

4• OWL (SHOIN(D))- W3C Recommendation since 2004

• OWL 2 (SHROIQ(D))- W3C Recommendation since 2009

OWL – Web Ontology Language




• OWL Ontology consists of






• Classes / properties / individuals (instances of classes)







• Open World Assumption








• „Absence of information must not be valued as negative information.“









• E.g.: sitsNextTo(PersonA, PersonB) PersonA may also sit next to another person…










• No Unique Name Assumption











• „Difference must be expressed explicitly“











• „Difference must be expressed explicitly“

• E.g.: PersonA possibly denotes the same individual as PersonB



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• OWL is a semantic fragment of FOL

• OWL exists in different flavors

FOL

SWRL/RIF OWL Full

OWL DL

OWL Lite RDFS

ConceptHierarchies

OWL ELOWL RLOWL QL


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• OWL Lite ⊆ OWL DL ⊆ OWL Full

FOL

SWRL/RIF OWL Full

OWL DL

OWL Lite RDFS

ConceptHierarchies

OWL ELOWL RLOWL QL

OWL1

OWL1Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam

Turmbau zu Babel, Pieter Brueghel, 1563

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FOL

SWRL/RIF OWL Full

OWL DL

OWL Lite RDFS

ConceptHierarchies

OWL ELOWL RLOWL QL


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• for OWL2:FOL

SWRL/RIF OWL Full

OWL DL

OWL Lite RDFSOWL ELOWL RLOWL QL

OWL2

ConceptHierarchies


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• for OWL2:

• OWL EL, OWL RL, OWL QL ⊆ OWL DL ⊆ OWL Full

FOL

SWRL/RIF OWL Full

OWL DL


OWL2

ConceptHierarchies

OWL2Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam

Turmbau zu Babel, Pieter Brueghel, 1563

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• for OWL2:

• OWL EL, OWL RL, OWL QL ⊆ OWL DL ⊆ OWL Full

FOL

SWRL/RIF OWL Full

OWL DL


OWL2

ConceptHierarchies


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OWL 1 DL is based on SHOIN(D)

• Axioms


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• Axioms

• TBox: subclass relationships C ⊑ D


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• Axioms


• RBox: subproperty relationships R ⊑ S (H),

inverse properties R- (I), transitivity ⊑+ (S)


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• Axioms




• ABox: facts for classes C(a), properties R(a,b), equality a=b, difference a≠b


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• Axioms





•Class constructors:


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• Axioms






• conjunction C⊓D, disjunction C⊔D, negation ¬C of classes


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• Axioms







• property restrictions: universal ∀R.C and existential ∃R.C


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• Axioms








• number restrictions: ≤n R and ≥n R (N)


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• Axioms









• closed classes (nominals): {a} (O)


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• Axioms









• closed classes (nominals): {a} (O)

•Datatypes (D)

Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam

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• OWL 2 can be represented in different Syntax variants

• Functional Syntax: substitutes abstract syntax of OWL 1

• RDF-Syntax: extension of existing OWL/RDF

• XML-Syntax: independent XML serialisation

• Manchester-Syntax: machine readable syntax, esp. for ontology editors

• Turtle: optional

• Functional Syntax is easy to define, no RDF restrictions, more compact

• RDF-Syntax important for compatibility issues

• Turtle: simple and efficient to write...

OWL Syntax Variants


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OWL 2 - Functional Syntax

SubClassOf( :Teenager DataSomeValuesFrom( :hasAge DatatypeRestriction( xsd:integer xsd:minExclusive "12"^^xsd:integer xsd:maxInclusive "19"^^xsd:integer ) ) )SubClassOf( :Woman :Person )SubClassOf( :Mother :Woman )...SubObjectPropertyOf( :hasWife :hasSpouse )SymmetricObjectProperty( :hasSpouse ) AsymmetricObjectProperty( :hasChild )...Declaration( NamedIndividual( :John ) )Declaration( NamedIndividual( :Mary ) )Declaration( NamedIndividual( :Jim ) )...ClassAssertion( :Person :Mary )ClassAssertion( :Woman :Mary )...ObjectPropertyAssertion( :hasWife :John :Mary )NegativeObjectPropertyAssertion( :hasWife :Bill :Mary )


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OWL 2 - Manchester Syntax

Class: Person Annotations: ... SubClassOf: owl:Thing that hasFirstName exactly 1 and hasFirstName only string[minLength 1] ,... SubClassOf: hasAge exactly 1 and hasAge only not NegInt,... SubClassOf: hasGender exactly 1 and hasGender only {female , male} ,... SubClassOf: not hates Self, ... EquivalentTo: g:People ,... DisjointWith: g:Rock , g:Mineral ,...

ObjectProperty: hasWife Annotations: ... Characteristics: Functional, InverseFunctional, Reflexive, Irreflexive, Asymmetric, Transitive Domain: Man Range: Person, Woman SubPropertyOf: hasSpouse, loves EquivalentTo: isMarriedTo ,... DisjointWith: hates ,... InverseOf: hasSpouse

Individual: John Annotations: ... Types: Person , hasFirstName value "John" or hasFirstName value "Jack"^^xsd:string Facts: hasWife Mary, not hasChild Susan, hasAge 33, hasChild _:child1 SameAs: Jack ,... DifferentFrom: Susan ,...


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OWL 2 - Turtle Syntax

:HappyPerson a owl:Class ; owl:equivalentClass [ a owl:Class ; owl:intersectionOf ([ a owl:Restriction ; owl:onProperty :hasChild ; owl:allValuesFrom :HappyPerson ] [ a owl:Restriction ; owl:onProperty :hasChild ; owl:someValuesFrom :HappyPerson ] ) ].


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Standard Namespaces and Prefixes

(cf. http://www.w3.org/TR/owl2-syntax/ )

http://prefix.cc/

http://www.w3.org/TR/owl2-syntax/

http://www.w3.org/TR/owl2-syntax/

http://prefix.cc

http://prefix.cc


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05 Web Ontology Language - OWL (Part 2)Open HPI - Course: Semantic Web Technologies - Lecture 5: Knowledge Representations II

OpenHPI 5.4 - Web Ontology Language

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