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Overview of Classes and Properties in OWL Lite for CmpE 583

This text outlines fundamental concepts of OWL Lite, specifically focusing on classes and properties. Classes in OWL represent domains and can be simple named classes or predefined ones like owl:Thing and owl:Nothing. Properties associate values with individuals and come in four types: datatype, object, annotation, and ontology properties. This guide provides examples of how to declare these elements, including syntax for defining datatype and object properties, highlighting their relationships and use cases in ontology development.

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Overview of Classes and Properties in OWL Lite for CmpE 583

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  1. Basic OWL Lite off TextbookCh. 12: Classes & Properties Atilla Elçi CmpE 583 Fall 2006

  2. Basic OWL Lite • Involves class and property declarations. • Class: • Represents domains in OWL • Subclass of rdfs:Class • Two kinds: • Simple Named Classes • Predefined Classes • Property: • Associates values with individuals • By relating individuals to datatype or another individual • Can be a class to representing variety of property specification • Relates an instance of a domain to an instance of a range • There are four disjoint types of properties in OWL Lite: • Datatype • Object • Annotation • Ontology properties. CmpE 583 Fall 2006

  3. Basic OWL Lite: Classes Simple Named Class (owl:Class): • Classes are named using upper CamelCase • User defines a simple named class as follows: <owl:Class rdf:ID=“MyOntologyClass”/> or, may include class properties as well. • rdf:ID signals that a new resource is being defined. • Ref to a class: • Internally by URIRef fragment: #MyOntologyClass • Externally by full URIRef. CmpE 583 Fall 2006

  4. Basic OWL Lite: Classes (continued) Predefined Classes (Extreme Classes): • Thing Class (owl:Thing): • A super class for all classes • Every individual is a member • Every class is a subclass • Everything about owl:Thing applies to everything! • Can use typed node syntax:instead of rdf:resource=“URIRef” use <rdf:Thing rdf:about=“URIRef” /> • Nothing Class (owl:Nothing): • Subclass of all classes • Empty class (has no individual members). CmpE 583 Fall 2006

  5. Basic OWL Lite: Properties There are four disjoint types of properties in OWL Lite: • Datatype • Object • Annotation • Ontology properties <owl:Ontology rdf:about=“URI”> where “URI” is either: • Each type is a subclass of rdf:Property • Datatype Property (owl:DatatypeProperty) class: • Identifies a property whose value is associated with a datatype such as literal rather than resources. • For example, in defining sessionStartTime as a datatype property type: <owl:DatatypeProperty rdf:ID=“sessionStartTime”> <rdfs:domain rdf:resource=“#Lecture” /> <rdfs:range rdf:resource=“&xsd;time”> </owl:DatatypeProperty> • The use of this property type: <sessionStartTime rdf:datatype=“&xsd;time”>8:30:00:00+01:00</session...> • Compare that with the following: rdf:about=“...” <train:Lecture rdf:ID=“CmpE583”> <startTime>8:30:00+01:00</startTime> </train:Lecture> CmpE 583 Fall 2006

  6. Basic OWL Lite: Properties (continued) • Object Properties (owl:ObjectProperty) class: • Identifies a property whose value is a reference to an individual (resource). • For example, in defining taughtBy as an object property: <owl:ObjectProperty rdf:ID=“taughtBy”/> • The use of this property could be: <Person rdf:ID=“aelci”> <givenName>Atilla</givenName> </Person> <train:Lecture rdf:ID=“CmpE583”> <rdfs:label>Web Semantics</rdfs:label > <startTime>8:30:00+01:00</startTime > <taughtBy rdf:resource=“#aelci” /> </train:Lecture> CmpE 583 Fall 2006

  7. Basic OWL Lite: Properties (continued) • Annotation Properties (owl:AnnotationProperty) class: • Identifies a special type of property whose value is a named class, property, individual, or ontology. • For example, in defining annotation property on taughtBy (referred to as a URIRef): <owl:AnnotationProperty rdf:about=“#taughtBy” > <propertyX .... /> <propertyY .... /> </owl:AnnotationProperty> • There are predefined OWL annotation properties: • rdfs:label • rdfs:comment • rdsf:seeAlso • rdfs:isDefinedBy • owl:versionInfo CmpE 583 Fall 2006

  8. Basic OWL Lite: Properties (continued) • Ontology Properties (owl:OntologyProperty) class: • Identifies a type of property which relates to ontologies. • There are predefined OWL ontology properties: • owl:imports • owl:backwardCompatibleWith • owl:incompatibleWith • owl:priorVersion CmpE 583 Fall 2006

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