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Rdf Overview Presentation


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A brief overview of RDF and its uses in a library environment.

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Rdf Overview Presentation

  1. 1. Introduction to RDF Ken Varnum 9 October 2007
  2. 2. Definition of RDF <ul><li>The Resource Description Framework (RDF) is a general-purpose language for representing information in the Web. </li></ul><ul><li>RDF Vocabulary Description Language 1.0: RDF Schema </li></ul><ul><li>Significant Part of “Semantic Web” </li></ul><ul><li>XML-based tool for describing resources </li></ul>
  3. 3. What’s It Good For? <ul><li>“… [D] oes not specify a vocabulary of descriptive properties such as &quot;author&quot;. Instead it specifies mechanisms that may be used to name and describe properties and the classes of resource they describe.” </li></ul><ul><li>Used to describe </li></ul><ul><ul><li>Source of ontology </li></ul></ul><ul><ul><li>What is being described </li></ul></ul><ul><ul><li>Description </li></ul></ul><ul><li>Not an Ontology </li></ul>
  4. 4. Concept of “Triples” <ul><li>Subject - Predicate - Object </li></ul><ul><ul><li>Something </li></ul></ul><ul><ul><li>Has the Property </li></ul></ul><ul><ul><li>Characteristic </li></ul></ul><ul><li>Properties are defined -- in human- or machine-readable format -- at a given URI. </li></ul>
  5. 5. Example <ul><li>Michigan has the postal abbreviation MI </li></ul>MI has the postal abbreviation Michigan Object Predicate Subject
  6. 6. Convert to RDF -- Step 1 <ul><li>First do the XML thing -- declare name spaces </li></ul><ul><li><rdf:RDF xmlns:rdf= xmlns:terms=&quot;;> </li></ul><ul><li></rdf:RDF> </li></ul><ul><li>Two name spaces </li></ul><ul><ul><li>rdf (defined by W3C) </li></ul></ul><ul><ul><li>terms (defined by Dublin Core) </li></ul></ul>
  7. 7. Convert to RDF -- Step 2 <ul><li>Add Subject </li></ul><ul><li><rdf:RDF xmlns:rdf= xmlns:terms=&quot;;> </li></ul><ul><li><rdf:Description rdf:about=&quot;urn:x-states:Michigan&quot;> </li></ul><ul><li></rdf:Description> </li></ul><ul><li></rdf:RDF> </li></ul><ul><li>Use “Description” from the RDF namespace </li></ul><ul><li>Definition found at RDF “x-states” site </li></ul>
  8. 8. Convert to RDF -- Step 3 <ul><li>Add Object </li></ul><ul><li><rdf:RDF xmlns:rdf= xmlns:terms=&quot;;> </li></ul><ul><li><rdf:Description rdf:about=&quot;urn:x-states:Michigan&quot;> </li></ul><ul><li><terms:alternative>MI</terms:alternative> </li></ul><ul><li></rdf:Description> </li></ul><ul><li></rdf:RDF> </li></ul><ul><li>Use “alternative” from the terms namespace </li></ul><ul><li>Definition found at Dublin Core site </li></ul><ul><li>DC only defines purpose of “alternative” in a machine-readable way </li></ul>
  9. 9. Where Is It? <ul><li>A “flavor” of RSS </li></ul><ul><ul><li>RDF </li></ul></ul><ul><ul><li>RSS </li></ul></ul><ul><ul><li>Atom </li></ul></ul><ul><li>Underlies data exchange </li></ul><ul><li>As a rule, systems generate it, not people </li></ul>
  10. 10. Foundation of “Semantic Web” <ul><li>“ 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.” </li></ul><ul><li>“ What Is RDF” by Joshua Tauberer </li></ul>
  11. 11. Sources / Further Reading <ul><li>Wikipedia entry on RDF (overview) </li></ul><ul><li>RDF Specification (technical) </li></ul><ul><li>What Is RDF (overview) </li></ul>