Resource Description Framework (RDF) developed by World Wide Web Consortium (W3C) by Satya

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Resource Description Framework(RDF)developed
by World Wide Web Consortium(W3C)bySatya
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How do we find things in real world

• Library
• Video store
• Phonebook
• Each of these systems is based on metadata
• i.e. data about data. This data about data is
  called metadata
• What about the web
• Dumb, brute force method
• hardly any metadata

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Library
Video store
Telephone Directory
metadata1
metadata2
metadata3
???
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RDF

• Is the foundation for processing metadata.
• Enables automated processing of web resources.
• Provides a generic metadata architecture.
• Uses XML as its language.

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Applications of RDF

• In resource discovery.
• In cataloging.
• Digital Libraries.
• Intelligent Software Agents.
• Web of trust.

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RDF model

• Presents an abstract, conceptual view framework
  for defining metadata.
• It is based on the following concepts.
• Resources These are the things being described
  by RDF
• expressions. e.g.www.umr.edu or a part of it
  e.g.
• www.umr.edu/madrias.
• Property Is a specific aspect, characteristic,
  attribute or relation used to describe a
  resource.
• Statement A statement in RDF consists of
• resource property value
  
• subject predicate object

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example

• For the statement Sanjay Madria is the creator
  of the web page www.umr.edu/madrias.
• We have RDF statement as
• And node and arc diagram as

Subject(resource)
www.umr.edu/madrias
Predicate(property)
creator
Object(literal)
Sanjay Madria
www.umr.edu/madrias
Sanjay Madria
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RDF syntax

• RDF syntax is needed for the purpose of creating
  and exchanging the metadata.
• 1RDF 'ltrdfRDFgt' description
  'lt/rdfRDFgt'
• 2description 'ltrdfDescription'
  idAboutAttr? 'gt'
• propertyElt
  'lt/rdfDescriptiongt
• 3 idAboutAttr idAttr aboutAttr
• 4 aboutAttr 'about"' URI-reference '"
• 5 idAttr 'ID"' IDsymbol '"
• 6 propertyElt 'lt' propName 'gt' value 'lt/'
  propName 'gt
• 'lt' propName
  resourceAttr '/gt
• 7 propName NSprefix '' name
• 8 value description string
• 9 resourceAttr 'resource"' URI-reference
  '"'
• 10 URI-reference string, interpreted per
  URI
• 11 IDsymbol (any legal XML name symbol)
• 12 name (any legal XML name symbol)
• 13 NSprefix (any legal XML namespace
  prefix)
• 14 string (any XML text, with "lt", "gt", and
  "" escaped)

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• Description contains the statements about
  resource.
• idAboutAttr indicates which resource is being
  described
• idAttr gives the anchor-id of the resource
• aboutAttrgives the URI of the resource being
  decribed.
• PropertyEltcontains the name of the property and
  the value of the property.
• PropertyName Gives the name of the property
  using namesapaces.
• valuecan be another resource or a literal.
• resourceAttr Specifies some other resource that
  is the value of this property.
• IDsymbol, nameany legal name symbol.
• NSprefixcorresponds to XML namespaces
• Stringcorresponds to XML text.

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Example

• For the statement Sanjay Madria is the creator
  of the resource www.umr.edu/madrias
• We have the RDF syntax(using XML) as
• ltrdfRDFgt
• ltrdfDescription aboutwww.umr.edu/madriasgt
• ltsCreatorgtSanjay Madrialt/screatorgt
• lt/rdfDescriptiongt
• lt/rdfRDFgt

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RDF schema

• Provides the mechanism for declaring properties
  and also defining relationship between these
  properties and other resources
• SrdfssubclassOf trdftype
• t s
  t
  t
  
• 
  t
  
  t t
  
  t
• 
  t
  
  
• t t
  t s
  t
  
  
• 
  s s t
  t t t
• 
  s
• t
  
  t

rdfslabel
rdfs Literal
rdfsResource
rdfsClass
rdfscomment
rdfProperty
rdfsisDefinedBy
rdfsConstraintResource
rdfsseeAlso
rdfssubPropertyOf
rdfsContainerMembershipProperty
rdfssubCLassof
rdfstype
rdfsConstraintProperty
rdfsrange
rdfsdomain
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Example

• 
  s
• t
  t
• t
  t
• 
  t s t
• 
  s
• 
  
  s s
• s
  t
• 
  s
  

rdfclass
rdfResource
xyzMotor Vehicle
xyzVan
xyzPassenger Vehicle
xyzTruck
xyzMini Van
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Advantages

• Interoperability of metadata
• Machine understandable semantic discovery
• better precision in resource discovery.
• Uniform query capability for resource
• discovery

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Conclusion

• Distributed Information on web.
• Metadata
• Introduction to RDF
• The various concepts of RDF.