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Uploaded byKen Varnum
Rdf Overview Presentation
RDF is a general-purpose language for representing information on the web. It allows for describing resources and the relationships between them using subject-predicate-object expressions called triples. RDF is used as a foundation for the semantic web and allows machines to mechanically process and interpret the logical pieces of meaning in data. While RDF does not define specific properties or vocabularies, it provides mechanisms for describing properties and classes of resources in a human- or machine-readable format.
Rdf Overview Presentation
- 1. Introduction to RDFKen Varnum 9 October 2007
- 2. Definition of RDFThe Resource Description Framework (RDF) is a general-purpose language for representing information in the Web. RDF Vocabulary Description Language 1.0: RDF Schema Significant Part of “Semantic Web” XML-based tool for describing resources
- 3. What’s It GoodFor? “… [D] oes not specify a vocabulary of descriptive properties such as "author". Instead it specifies mechanisms that may be used to name and describe properties and the classes of resource they describe.” Used to describe Source of ontology What is being described Description Not an Ontology
- 4. Concept of “Triples”Subject - Predicate - Object Something Has the Property Characteristic Properties are defined -- in human- or machine-readable format -- at a given URI.
- 5. Example Michigan hasthe postal abbreviation MI MI has the postal abbreviation Michigan Object Predicate Subject
- 6. Convert to RDF-- Step 1 First do the XML thing -- declare name spaces <rdf:RDF xmlns:rdf=http://www.w3.org/1999/02/22-rdf-syntax-ns# xmlns:terms="http://purl.org/dc/terms/"> </rdf:RDF> Two name spaces rdf (defined by W3C) terms (defined by Dublin Core)
- 7. Convert to RDF-- Step 2 Add Subject <rdf:RDF xmlns:rdf=http://www.w3.org/1999/02/22-rdf-syntax-ns# xmlns:terms="http://purl.org/dc/terms/"> <rdf:Description rdf:about="urn:x-states:Michigan"> </rdf:Description> </rdf:RDF> Use “Description” from the RDF namespace Definition found at RDF “x-states” site
- 8. Convert to RDF-- Step 3 Add Object <rdf:RDF xmlns:rdf=http://www.w3.org/1999/02/22-rdf-syntax-ns# xmlns:terms="http://purl.org/dc/terms/"> <rdf:Description rdf:about="urn:x-states:Michigan"> <terms:alternative>MI</terms:alternative> </rdf:Description> </rdf:RDF> Use “alternative” from the terms namespace Definition found at Dublin Core site DC only defines purpose of “alternative” in a machine-readable way
- 9. Where Is It?A “flavor” of RSS RDF RSS Atom Underlies data exchange As a rule, systems generate it, not people
- 10. Foundation of “SemanticWeb” “ What is meant by ‘semantic’ in Semantic Web is not that computers are going to understand the meaning of anything, but that the logical pieces of meaning can be mechanically manipulated by a machine to useful human ends.” “ What Is RDF” by Joshua Tauberer
- 11. Sources / FurtherReading Wikipedia entry on RDF (overview) http://en.wikipedia.org/wiki/Resource_Description_Framework RDF Specification (technical) http://www.w3.org/RDF/ What Is RDF (overview) http://www.xml.com/lpt/a/1665