OpenHPI 2.6 - How to Model Classes and Relations - RDFS
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OpenHPI 2.6 - How to Model Classes and Relations - RDFS

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  • 1. Semantic Web TechnologiesLecture 2: Semantic Web - Basic Architecture I 06: How to Model Classes and Relations? - RDFS 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. 2Lecture 2: Semantic Web - Basic Architecture I Open HPI - Course: Semantic Web Technologies Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 3. 06 How to Model Classes and Relations? - RDFSOpen HPI - Course: Semantic Web Technologies - Lecture 2: Semantic Web Basic Architecture I3 SO ... WE NEED A WAY TO DEFINE RDF SCHEMATA FOR CLASSES AND RELATIONS ?! Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 4. 2. Semantic Web - Basic Architecture Languages of the Semantic Web - Part 14 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 5. Why RDFSchema...?5 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 6. Why RDFSchema...?5 • An application program can define and use RDF data Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 7. Why RDFSchema...?5 • An application program can define and use RDF data • ….if the application program knows, which terms and classes to use, as e.g. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 8. Why RDFSchema...?5 • An application program can define and use RDF data • ….if the application program knows, which terms and classes to use, as e.g. • name, title, year, … Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 9. Why RDFSchema...?5 • An application program can define and use RDF data • ….if the application program knows, which terms and classes to use, as e.g. • name, title, year, … • name, blog, phone number… Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 10. Why RDFSchema...?5 • An application program can define and use RDF data • ….if the application program knows, which terms and classes to use, as e.g. • name, title, year, … • name, blog, phone number… • author, cites, … Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 11. Why RDFSchema...?5 • An application program can define and use RDF data • ….if the application program knows, which terms and classes to use, as e.g. • name, title, year, … • name, blog, phone number… • author, cites, … • But..... Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 12. Why RDFSchema...?5 • An application program can define and use RDF data • ….if the application program knows, which terms and classes to use, as e.g. • name, title, year, … • name, blog, phone number… • author, cites, … • But..... • Are all terms known? Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 13. Why RDFSchema...?5 • An application program can define and use RDF data • ….if the application program knows, which terms and classes to use, as e.g. • name, title, year, … • name, blog, phone number… • author, cites, … • But..... • Are all terms known? • Are all terms correct? Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 14. Why RDFSchema...?5 • An application program can define and use RDF data • ….if the application program knows, which terms and classes to use, as e.g. • name, title, year, … • name, blog, phone number… • author, cites, … • But..... • Are all terms known? • Are all terms correct? • Are there (logical) relations among the terms? Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 15. Why RDFSchema...?5 • An application program can define and use RDF data • ….if the application program knows, which terms and classes to use, as e.g. • name, title, year, … • name, blog, phone number… • author, cites, … • But..... • Are all terms known? • Are all terms correct? • Are there (logical) relations among the terms? • We need a language for data definition: RDF Schema Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 16. Why RDFSchema...?5 • An application program can define and use RDF data • ….if the application program knows, which terms and classes to use, as e.g. • name, title, year, … • name, blog, phone number… • author, cites, … • But..... • Are all terms known? • Are all terms correct? • Are there (logical) relations among the terms? • We need a language for data definition: RDF Schema • officially called “RDF Vocabulary Description Language” Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 17. RDFSchema6 • First W3C draft in April 1998, W3C Recommendation Feb. 2004. • RDF Schema defines a data model for the creation of RDF statements • RDFSchema allows: • Definition of classes •Class instantiation in RDF via <rdf:type> • Definition of properties and restrictions • Definition of hierarchies •Subclasses and superclasses •Subproperties and superproperties Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 18. Vocabulary7 • Classes • rdfs:Class Concept of a class, defines an abstract object and is applied (with rdf:type) to create instances • rdf:Property Base class for properties • rdfs:Literal Class for literals • rdfs:Resource every entity of an RDF model is instance of this class • and additionally rdfs:Datatype, rdf:XMLLiteral, rdfs:Container, rdfs:ContainerMembershipProperty Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 19. Example8 rdfs:Resource rdfs:subClassOf rdfs:subClassOf rdfs:subClassOf rdfs:Class rdf:Property rdfs:Class rdf:type rdf:type rdf:type domain Lecture range isManagedBy Staff RDFS rdf:type rdf:type RDF exv:SemanticWebTechnologies exv:HaraldSack exv:isManagedBy Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 20. Vocabulary9 •Properties • rdfs:subClassOf transitive property to define inheritance hierarchies for classes • rdfs:subPropertyOf transitive property to define inheritance hierarchies for properties • rdfs:domain defines the domain of a property concerning a class • rdfs:range defines range of a property concerning a class Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 21. Example10 rdfs:Class rdf:Property rdfs:Class rdf:type rdf:type rdf:type class rdfs:domain property class Course isManagedBy rdfs:range Staff subClassOf subClassOf subClassOf class class subClassOf class class Seminar Lecture Prof. SeniorResearcher RDFS rdf:type rdf:type RDF exv:SemanticWebTechnologies exv:HaraldSack exv:isManagedBy Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 22. Language Model t t rdfs:Class rdfs:Resource s s – subclass relation t – instance relationSemantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 23. Language Model t t rdfs:Class rdfs:Resource s t s rdfs:Literal s – subclass relation t – instance relationSemantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 24. Language Model t t rdfs:Class rdfs:Resource s t t s s rdfs:Literal rdf:Property s – subclass relation t – instance relationSemantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 25. Language Model t t rdfs:Class rdfs:Resource s t t s s t rdfs:Literal rdf:Property rdf:type t t t t rdfs:comment t rdfs:range rdfs:domain rdfs:subClassOf s – subclass relation rdfs:subPropertyOf t – instance relationSemantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 26. Vocabulary12 • Further Properties • rdfs:seeAlso defines a relation of a resource to another, which explains it • rdfs:isDefinedBy subproperty of rdf:seeAlso, defines the relation of a resource to its definition • rdfs:comment comment, usually as text • rdfs:label „readable“ name of a resource (contrary to ID) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 27. RDF(S) Knowledge Base13 T-Box Terminologcal Knowledge Person rdfs:subClassOf rdfs:domain Course rdfs:range is managed by Staffrdfs:subClassOf rdfs:subClassOf rdfs:subClassOf rdfs:subClassOf Seminar Lecture Prof. SeniorResearcher RDFSA-Box rdf:type RDF rdf:typeAssertional Knowledge exv:SemanticWebTechnologies exv:HaraldSack exv:isManagedBy Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 28. Example@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> Turtle@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>:Course a rdfs:Class .:Lecture a rdfs:Class; rdfs:subClassOf :Course.:Seminar a rdfs:Class ; rdfs:subClassOf :Course.:Person a rdfs:Class .:Staff a rdfs:Class ; rdfs:subClassOf :Person .:SeniorResearcher a rdfs:Class ; rdfs:subClassOf :Staff .:Professor a rdfs:Class ; rdfs:subClassOf :Staff .:isManagedBy a rdf:Property; rdfs:domain :Course ; rdfs:range :Staff .:SemanticWebTechnologies a :Lecture .:HaraldSack a :SeniorResearcher .:SemanticWebTechnologies :isManagedBy :HaraldSack .Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 29. RDFS Summary • RDFSchema defines a data model for the definition of simple ontologies (knowledge representations). • Via RDFSchema ontologies RDF statements (facts) can be expressed • More than XML: • (small) ontological agreement about modelling primitives • Possibility to define own vocabulariesSemantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam
  • 30. 07 How much semantics is there in RDF(S)Open HPI - Course: SemanticHarald Sack, Hasso-Plattner-Institut, Universität Potsdam Semantic Web Technologies , Dr. Web Technologies - Lecture 2: Semantic Web Basic Architecture I