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RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
RDF and OWL
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RDF and OWL

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A simple overview of the building blocks of the Semantic Web. I created this to present to the Semantic Web Affinity Group at Razorfish.

A simple overview of the building blocks of the Semantic Web. I created this to present to the Semantic Web Affinity Group at Razorfish.

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  • 1. RDF & OWL A simple overview of the b uilding blocks of the Semantic Web Presented by Rachel Lovinger Semantic Web Affinity Group December 2007
  • 2. RDF = Resource Description Framework
  • 3. <ul><li>Purpose: To provide a structure (aka framework) for describing identified things (aka resources) </li></ul>RDF
  • 4. <ul><li>Identified ? </li></ul><ul><li>In order to make meaningful statements in RDF, the thing you’re talking about has to be identified in some unique way. </li></ul><ul><li>http://www.foaf.com/Person#RachelLovinger </li></ul><ul><li>http://www.allmovie.com/Actor#WillSmith </li></ul><ul><li>URIs (uniform resource identifiers) look like URLs, but they may not represent an actual web page. </li></ul>RDF
  • 5. <ul><li>Composed of three basic elements </li></ul><ul><li>Resources – the things being described </li></ul><ul><li>Properties – the relationships between things </li></ul><ul><li>Classes – the buckets used to group the things </li></ul>RDF
  • 6. <ul><li>The elements are combined to make simple statements in the form of Triples </li></ul><ul><li><Subject> <Predicate> <Object> </li></ul><ul><li>Men In Black stars Will Smith </li></ul><ul><li><MenInBlack> <hasStar> <WillSmith> </li></ul>RDF
  • 7. <ul><li>Information Expressed in Triples </li></ul><ul><li><http://www.w3.org/2001/sw/RDFCore/ntriples/> <dc:creator> &quot;Dave Beckett&quot; . </li></ul><ul><li><http://www.w3.org/2001/sw/RDFCore/ntriples/> <dc:creator> &quot;Art Barstow&quot; . </li></ul><ul><li><http://www.w3.org/2001/sw/RDFCore/ntriples/> <dc:publisher> <http://www.w3.org/> . </li></ul><ul><li>Can also be expressed as XML </li></ul><ul><li><rdf:RDF xmlns:rdf=&quot;http://www.w3.org/1999/02/22-rdf-syntax-ns#&quot; xmlns:dc=&quot;http://purl.org/dc/elements/1.1/&quot;> </li></ul><ul><li><rdf:Description rdf:about=&quot;http://www.w3.org/2001/sw/RDFCore/ntriples/&quot;> <dc:creator>Art Barstow</dc:creator> </li></ul><ul><li><dc:creator>Dave Beckett</dc:creator> </li></ul><ul><li><dc:publisher rdf:resource=&quot;http://www.w3.org/&quot;/> </li></ul><ul><li></rdf:Description> </li></ul><ul><li></rdf:RDF> </li></ul>RDF
  • 8. <ul><li>RDF Properties </li></ul><ul><li>type </li></ul><ul><li>subClassOf </li></ul><ul><li>subPropertyOf </li></ul><ul><li>range </li></ul><ul><li>domain </li></ul><ul><li>label </li></ul><ul><li>comment </li></ul>RDF
  • 9. <ul><li>type – a resource belongs to a certain class </li></ul><ul><li><WillSmith> <type> <Actor> </li></ul><ul><li>This defines which properties will be relevant to Will Smith. </li></ul>RDF
  • 10. <ul><li>subClassOf – a class belongs to a parent class </li></ul><ul><li><Actor> <subClassOf> <Person> </li></ul><ul><li>This means that all members of the actor class are also members of the Person class. All properties are inherited, and new properties specific to Actor can be added. </li></ul><ul><li><WillSmith> <type> <Actor> </li></ul><ul><li>implies <WillSmith> <type> <Person> </li></ul>RDF
  • 11. <ul><li>subPropertyOf – a property has a parent property </li></ul><ul><li><hasStar> <subPropertyOf> <hasActor> </li></ul><ul><li>This means that, if you make a statement using the hasStar property, a more general statement using the hasActor property is also true. </li></ul><ul><li><MenInBlack> <hasStar> <WillSmith> </li></ul><ul><li>implies <MenInBlack> <hasActor> <WillSmith> </li></ul>RDF
  • 12. <ul><li>range & domain – the types of resources that use a property </li></ul><ul><li><hasStar> <range> <Actor> </li></ul><ul><li><hasStar> <domain> <Movie> </li></ul><ul><li>This means that, if you make a statement using the hasStar property, the system will assume that the subject is a Movie and the object is an Actor. </li></ul><ul><li><WillSmith> <hasStar> <MenInBlack> </li></ul><ul><li>is an untrue statement, but not invalid </li></ul>RDF
  • 13. <ul><li>label – a human-readable name for a resource </li></ul><ul><li><http://www.allmovie.com/Actor#WillSmith> <label> <Will Smith> </li></ul>RDF
  • 14. <ul><li>comment – a human-readable description </li></ul><ul><li><https://aarfwiki.main.corp/wiki/index.php/File:RDF_OWL.pdf> <comment> <A presentation that Rachel gave at the December 2007 Semantic Web Affinity Group Meeting> </li></ul>RDF
  • 15. RDF Blackberry Fruit typeOf BerryPie EdibleThing typeOf subClassOf ingredientOf Blackberry
  • 16. <ul><li>Why is RDF uniquely suited to expressing data and data relationships? </li></ul><ul><li>More flexible – data relationships can be explored from all angles </li></ul><ul><li>More efficient – large scale, data can be read more quickly </li></ul><ul><ul><li>not linear like a traditional database </li></ul></ul><ul><ul><li>not hierarchical like XML </li></ul></ul>RDF
  • 17. Namespaces
  • 18. <ul><li>A method for qualifying names used in an XML document. Can be used to indicate usage of a standard, or to specify a unique version of the term. </li></ul><ul><li>dc:creator </li></ul><ul><li>rdf:type </li></ul><ul><li>foaf:Person </li></ul><ul><li>foaf:knows </li></ul><ul><li>aarf:Employee </li></ul>Namespaces
  • 19. OWL = Web Ontology Language
  • 20. OWL
  • 21. <ul><li>Purpose: To develop ontologies that are compatible with the World Wide Web. </li></ul>OWL
  • 22. <ul><li>Ontologies ? </li></ul><ul><li>Definition and classification of concepts and entities, and the relationships between them. </li></ul>OWL
  • 23. <ul><li>Based on the basic elements of RDF; adds more vocabulary for describing properties and classes. </li></ul><ul><li>Relationships between classes (ex: disjointWith) </li></ul><ul><li>Equality (ex: sameAs) </li></ul><ul><li>Richer properties (ex: symmetrical) </li></ul><ul><li>Class property restrictions (ex: allValuesFrom) </li></ul>OWL
  • 24. <ul><li>Relationships between Classes </li></ul><ul><li>disjointWith – resources belonging to one class cannot belong to the other </li></ul><ul><li><Person> <disjointWith> <Country> </li></ul><ul><li>complementOf – the members of one class are all the resources that do not belong to the other </li></ul><ul><li><InanimateThings> <complementOf> <LivingThings> </li></ul>OWL
  • 25. <ul><li>Equality </li></ul><ul><li>sameAs – indicates that two resources actually refer to the same real-world thing or concept </li></ul><ul><li><wills> <sameAs> <wismith> </li></ul><ul><li>equivalentClass – indicates that two classes have the same set of members </li></ul><ul><li><CoopBoardMembers> <equivalentClass> <CoopResidents> </li></ul>OWL
  • 26. <ul><li>Richer Properties </li></ul><ul><li>Symmetric – a relationship between A and B is also true between B and A </li></ul><ul><li><WillSmith> <marriedTo> <JadaPinkettSmith> </li></ul><ul><li>implies <JadaPinkettSmith> <marriedTo> <WillSmith> </li></ul><ul><li>Transitive – a relationship between A and B and between B and C is also true between A and C </li></ul><ul><li><piston> <isPartOf> <engine> </li></ul><ul><li><engine> <isPartOf> <automobile> </li></ul><ul><li>implies <piston> <isPartOf> <automobile> </li></ul>OWL
  • 27. <ul><li>Richer Properties continued </li></ul><ul><li>inverseOf – a relationship of type X between A and B implies a relationship of type Y between B and A </li></ul><ul><li><starsIn> <inverseOf> <hasStar> </li></ul><ul><li><MenInBlack> <hasStar> <WillSmith> </li></ul><ul><li>implies <WillSmith> <starsIn> <MenInBlack> </li></ul>OWL
  • 28. <ul><li>Class Property Restrictions – define the members of a class based on their properties </li></ul><ul><li>allValuesFrom – resources with properties that only have values that meet this criteria </li></ul><ul><ul><li>Example: Property: hasParents, allValuesFrom: Human </li></ul></ul><ul><ul><li>Resources that meet this criteria can be defined as also being members of the Human class </li></ul></ul><ul><li>someValuesFrom – resources with properties that have at least one value that meets criteria </li></ul><ul><ul><li>Example: Property: hasGraduated, someValuesFrom: College </li></ul></ul><ul><ul><li>Resources that meet this criteria can be defined as being members of the CollegeGraduates class </li></ul></ul>OWL
  • 29. <ul><li>This seems complicated. Why do it? </li></ul><ul><li>These capabilities allows systems to express and make sense of first order logic. </li></ul><ul><li>All men are mortal </li></ul><ul><li>Socrates is a man </li></ul><ul><li>Therefore, Socrates is mortal </li></ul>OWL
  • 30. <ul><li>Inferences </li></ul><ul><li>Create new triples based on existing triples </li></ul><ul><li>Deduce new facts based on the stated facts </li></ul><ul><li><piston> <isPartOf> <engine> </li></ul><ul><li><engine> <isPartOf> <automobile> </li></ul><ul><li>implies <piston> <isPartOf> <automobile> </li></ul>OWL
  • 31. <ul><li>Three Flavors of OWL </li></ul><ul><li>OWL Lite – uses a subset of the capabilities </li></ul><ul><li>OWL DL – uses all the capabilities, but some are used in restricted ways </li></ul><ul><li>OWL Full – unrestricted use of capabilities; no guarantee that all resulting statements are valid </li></ul>OWL
  • 32. SKOS = Simple Knowledge Organization System
  • 33. <ul><li>Also based on RDF </li></ul><ul><li>Designed specifically to express information that’s more hierarchical – broader terms, narrower terms, preferred terms and other thesaurus-like relationships </li></ul><ul><li>Extendable into OWL, if needed </li></ul>SKOS
  • 34. Need more?
  • 35. <ul><li>SchemaWeb: http://www.schemaweb.info/default.aspx </li></ul><ul><li>RDF Primer: http://www.w3.org/TR/REC-rdf-syntax/ </li></ul><ul><li>OWL / Semantic Web: http://www.w3.org/2004/OWL/ </li></ul><ul><li>SKOS: http://www.w3.org/2004/02/skos/ </li></ul><ul><li>Dublin Core: http://dublincore.org/ </li></ul><ul><li>Namespaces: http://www.w3.org/TR/REC-xml-names/ </li></ul><ul><li>URIs: http://www.w3.org/Addressing/ </li></ul>Resources

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