of 32 lecture 8: owl – language I

of 32 ece 627, winter ‘132 OWL XML/RDF syntax: header <rdf:RDF xmlns:owl =" xmlns:rdf =" xmlns:rdfs=" xmlns:xsd =" an OWL ontology may start with a collection of assertions for housekeeping purposes using owl:Ontology element

of 32 ece 627, winter ‘133 owl:Ontology An example OWL ontology <owl:priorVersion rdf:resource=" <owl:imports rdf:resource=" University Ontology …

of 32 ece 627, winter ‘134 owl:Ontology owl:imports means an ontology O1 imports another ontology O2, and then the entire set of declarations in O2 is appended to O1 importing ontology O2 will also import all of the ontologies that O2 imports

of 32 ece 627, winter ‘135 classes classes are defined using owl:Class  owl:Class is a subclass of rdfs:Class

of 32 ece 627, winter ‘136 classes (2) disjointness of classes is defined using owl:disjointWith

of 32 ece 627, winter ‘137 classes (3) owl:equivalentClass defines equivalence of classes

of 32 ece 627, winter ‘138 classes (4) owl:Thing is the most general class, which contains everything owl:Nothing is the empty class

of 32 ece 627, winter ‘139 properties in OWL there are two kinds of properties  object properties, which relate objects to other objects for example, is-TaughtBy, supervises  data type properties, which relate objects to datatype values for example, phone, title, age

of 32 ece 627, winter ‘1310 datatype properties OWL makes use of XML Schema data types, using the layered architecture of the Semantic Web <rdfs:range rdf:resource= " #nonNegativeInteger"/>

of 32 ece 627, winter ‘1311 object properties user-defined data types

of 32 ece 627, winter ‘1312 property restrictions introduction – anonymous superclass in OWL we can declare that the class C satisfies certain conditions  all instances of C satisfy the conditions this is equivalent to saying that C is subclass of a class C', where C' collects all objects that satisfy the conditions  C' can remain anonymous

of 32 ece 627, winter ‘1313 property restrictions introduction – anonymous superclass a (restriction) class is achieved through an owl:Restriction element this element contains an owl:onProperty element and one or more restriction declarations

of 32 ece 627, winter ‘1314 property restrictions introduction – anonymous superclass 1 2 … … declaration of restriction R … … 10 in Set Theory

of 32 ece 627, winter ‘1315 property restrictions introduction – anonymous superclass lines 4 to 7 define the (unnamed) class fo all things that satisfy R line 3 indicates that C is a sublass of such a (unnamed class) the pattern in lines 3 to 8 may be repeated to define multiple restrictions for the same class

of 32 ece 627, winter ‘1316 property restrictions (2) three types of restrictions: quantified restrictions value restrictions (filler information) cardinality restrictions

of 32 ece 627, winter ‘1317 property restrictions (3) quantified restrictions  owl:allValuesFrom specifies universal quantification (C P.D)  owl:someValuesFrom specifies existential quantification (C P.D)

of 32 ece 627, winter ‘1318 property restrictions (4) value restrictions  owl:hasValue specifies a specific value

of 32 ece 627, winter ‘1319 property restrictions (5) cardinality restrictions  owl:cardinality specifies the exact number of occurences of P each instance of C must have  owl:maxCardinality (owl:minCardinality)specifies the max (min) number of occurences of P each instance of C must have

of 32 ece 627, winter ‘1320 owl:someValuesFrom

of 32 ece 627, winter ‘1321 owl:allValuesFrom

of 32 ece 627, winter ‘1322 owl:hasValue

of 32 ece 627, winter ‘1323 cardinality restrictions 1

of 32 ece 627, winter ‘1324 properties of object properties owl:TransitiveProperty for example, “has better grade than”, “is ancestor of” R is transitive iff, for any x, y and z, if R(x,y) and R(y,z) then R(x,z)

of 32 ece 627, winter ‘1325 properties of object properties (2) owl:SymmetricProperty for example, “has same grade as”, “is sibling of” R is symmetric iff, for any x, y, R(x,y) iff R(y,x)

of 32 ece 627, winter ‘1326 properties of object properties (3) owl:FunctionalProperty defines a property that has at most one value for each object for example, “age”, “height”, “directSupervisor” R is functional iff, for any x, y and z, if R(x,y) and R(x,z) then y=z

of 32 ece 627, winter ‘1327 properties of object properties (4) owl:InverseFunctionalProperty defines a property for which two different objects cannot have the same value R is inverse functional iff, for any x, y and z, if R(y,x) and R(z,x) then y=z (only for OWL Full)

of 32 ece 627, winter ‘1328 properties of object properties (5) owl:InverseOf S is the inverse of R iff, for any x, y, R(x,y) iff S(y,x)

of 32 ece 627, winter ‘1329 properties of object properties – example

of 32 ece 627, winter ‘1330 properties of object properties – example

of 32 ece 627, winter ‘1331 properties of object properties – example

of 32 ece 627, winter ‘1332 owl:equivalentProperty properties of object properties – example