Resource Description Framework

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Resource Description Framework
Presentation by Ray James For Semantic Web UT
Austin, Spring 2006

• Out of chaos, order

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RDF overview

• What RDF is
• What RDF can do
• How to use RDF
• Current RDF applications
• RDFs future
• Summary Sources

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RDF basics

• Metadata is constructed information
• Metadata is developed by people for a purpose or
  function
• Metadata can be a surrogate

From Karen Coyle
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What RDF is

• Key Definitions
• Resource Description Framework An XML expression
  used to make simple assertions about
  relationships between things.
• RDF Schema A language used to describe the
  relationship between classes of things, or
  relationships between concepts in a particular
  domain.

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In other words

• RDF defines a convention essential for the
  Semantic Web
• RDF is machine and human readable but primarily
  for the machine
• RDF is an infrastructure that enables the
  encoding, exchange, and reuse of structured
  metadata.

Eric Miller
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What RDF is

• History dates just over a decade
• Creation process began in 1990s outgrowth of
  PICS
• First RDF working draft October 1997
• Semantic Web Activity first RDF Interest Group
  meeting, February 2001
• Collaborative design process

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What RDF is

• Breaking down RDF
• Anything can be a resource Web page, PDA,
  document, etc. (identified with URI)
• Description means how a resource is related to
  any other resource or object
• Framework means ontological construct

Source www.w3.org
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Describing RDF
RDF promotes semantic interoperability XML
promotes syntactic interoperability.
Diagram from Dr. Miles Efron lecture notes.
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Describing RDF

• RDF is all about the triples
• Resource, Property, Value
• Or
• Subject, Predicate, Object

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RDF triples graphically
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More on RDF triples

• An Object can become Subject of new triple
• Nesting of properties without limit
• Triples concept maintained in RDF Schema
• RDFS creates vocabularies
• RDFS triples are classes, class properties and
  (atomic) values

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RDF graphically
From Explorers Guide to the Semantic Web
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RDF in words

• There is a person who is named William Sparks who
  has a telephone number 435-555-6789 and who has
  an address which is composed of an address
  (number and street) and a city and a state and
  who has an e-mail account which was opened on
  Aug. 1, 2001 and uses the address
  wsparks_at_malto.com.

Subject Predicate Object Nested-subject Object
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Reification

• Reification describes the act of making a data
  model for a previously abstract concept.
• Reification allows a computer to process an
  abstraction as if it were any other data

From Wikipedia
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An RDF document
lt?xml version"1.0"?gt ltrdfRDF
xmlnsrdf"http//www.w3.org/1999/02/22-rdf-syntax
-ns" xmlnsdc"http//dublincore.org/2003/03/24/d
ces"gt ltrdfDescription rdfabout"http//www.ukol
n.ac.uk/metadata/resources/dc/datamodel/WD-dc-rdf/
"gt ltdctitlegt Guidance on expressing the Dublin
Core within the Resource Description Framework
(RDF) lt/dctitlegtltdccreatorgt Eric Miller
lt/dccreatorgtltdcsubjectgt Dublin Core Resource
Description Framework RDF eXtensible Markup
Language XML lt/dcsubjectgtltdcpublishergt Dublin
Core Metadata Initiative lt/dcpublishergtltdccontri
butorgt Dublin Core Data Model Working Group
lt/dccontributorgtltdcdategt 1999-07-01
lt/dcdategtltdcformatgt text/html
lt/dcformatgtltdclanguagegt en lt/dclanguagegtlt/rdfD
escriptiongt lt/rdfRDFgt
Adapted from http//www.ukoln.ac.uk/metadata/resou
rces/dc/datamodel/WD-dc-rdf
Subject Predicate Object
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In words

• There is a document declared in Dublin Core
  Schema found at the Dublin Core namespace ( RDF
  etc)
• http//www.ukoln.ac.uk/metadata/resources/dc/datam
  odel/WD-dc-rdf/
• which has the title Guidance on expressing the
  Dublin Core within the Resource Description
  Framework (RDF) created by Eric Miller whose
  subject keywords are Dublin Core Resource
  Description Framework RDF eXtensible Markup
  Language XML published by Dublin Core Metadata
  Initiative contributed by Dublin Core Data Model
  Working Group on the date 1999-07-01 written in
  the format text/html and in the language en
  (English).

Subject Predicate Object
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How RDF works

• All essential information is at
• http//www.w3.org/RDF
• Find RDF validator at the website
• http//www.w3.org/RDF/Validator/

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RDF applications
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RDF document

• lt!-- /Creative Commons License --gt
• lt!-- ltrdfRDF xmlns"http//web.resource.org/cc/
  " xmlnsdc"http//purl.org/dc/elements/1.1/
  " xmlnsrdf"http//www.w3.org/1999/02/22-rd
  f-syntax-ns"gt ltWork rdfabout""gt
  ltdctitlegtMetadata Data with a
  Purposelt/dctitlegt ltdcdategt2004lt/dcdategt
  ltdcdescriptiongtA general discussion of
  document/resource metadata and some related
  uses.lt/dcdescriptiongt ltdccreatorgtltAgentgt
  ltdctitlegtKaren Coylelt/dctitlegt
  lt/Agentgtlt/dccreatorgt ltdcrightsgtltAgentgt
  ltdctitlegtKaren Coylelt/dctitlegt
  lt/Agentgtlt/dcrightsgt ltdctype
  rdfresource"http//purl.org/dc/dcmitype/Text"
  /gt ltdcsource rdfresource"http//www.kcoyle
  .net/meta_purpose.html"/gt ltlicense
  rdfresource"http//creativecommons.org/licenses/
  by-nc-nd/2.0/" /gt lt/Workgt ltLicense
  rdfabout"http//creativecommons.org/licenses/by-
  nc-nd/2.0/"gt ltpermits rdfresource"http//we
  b.resource.org/cc/Reproduction" /gt ltpermits
  rdfresource"http//web.resource.org/cc/Distribut
  ion" /gt ltrequires rdfresource"http//web.re
  source.org/cc/Notice" /gt ltrequires
  rdfresource"http//web.resource.org/cc/Attributi
  on" /gt ltprohibits rdfresource"http//web.re
  source.org/cc/CommercialUse" /gt lt/Licensegt
  lt/rdfRDFgt

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RDF applications

• Mozilla describes e-mail, news
• RSS describes blogs
• Annotea describes Web pages
• Dublin Core describes meta data
• Webscripter defines and fuses

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RDF(S) creation applications
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More on Altova site
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RDFs Future

• Growing acceptance by Web site producers and
  users of metadata
• Programs like SemanticWorks are positive signs
  that standard is healthy
• Acceptance means use use means continuing
  acceptance
• Continued support (likely) from W3C

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RDF Summary

• RDF
• is about relationships.
• brings interoperability.
• is all about triples.
• can be found at http//www.w3.org/RDF

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Sources

• http//www.w3.org/RDF
• http//www.altova.com
• http//www.mozilla.org/rdf/doc/
• http//www-db.research.bell-labs.com/user/pfps/pub
  lications/oil-ieee.pdf
• OIL An Ontology Infrastructure (Fensel and
  others)
• www.dlib.org/dlib/may98/miller/05miller.html
• An Introduction to the Resource Development
  Framework (Miller)
• Explorers Guide to the Semantic Web (Passin)
• http//www.kcoyle.net/jal2_Metadata.html
• Understanding Metadata and Its Purpose
  (Coyle)

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Questions?