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

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

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

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  1. Resource Description Framework(RDF)developed by World Wide Web Consortium(W3C)bySatya

  2. 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

  3. Library Video store Telephone Directory metadata1 metadata2 metadata3 ???

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

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

  6. 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

  7. example Subject(resource) www.umr.edu/~madrias Predicate(property) creator 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 Object(literal) “Sanjay Madria” www.umr.edu/~madrias Sanjay Madria

  8. RDF syntax RDF syntax is needed for the purpose of creating and exchanging the metadata. [1]RDF ::= ['<rdf:RDF>'] description* ['</rdf:RDF>'] [2]description ::= '<rdf:Description' idAboutAttr? '>' propertyElt* '</rdf:Description>‘ [3] idAboutAttr ::= idAttr | aboutAttr [4] aboutAttr ::= 'about="' URI-reference '"‘ [5] idAttr ::= 'ID="' IDsymbol '"‘ [6] propertyElt ::= '<' propName '>' value '</' propName '>‘ | '<' propName resourceAttr '/>‘ [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 "<", ">", and "&" escaped)

  9. Description: contains the statements about resource. idAboutAttr: indicates which resource is being described idAttr: gives the anchor-id of the resource aboutAttr:gives the URI of the resource being decribed. PropertyElt:contains the name of the property and the value of the property. PropertyName: Gives the name of the property using namesapaces. value:can be another resource or a literal. resourceAttr: Specifies some other resource that is the value of this property. IDsymbol, name:any legal name symbol. NSprefix:corresponds to XML namespaces String:corresponds to XML text.

  10. Example: For the statement “Sanjay Madria is the creator of the resource www.umr.edu/~madrias We have the RDF syntax(using XML) as: <rdf:RDF> <rdf:Description about=“www.umr.edu/madrias”> <s:Creator>Sanjay Madria</s:creator> </rdf:Description> </rdf:RDF>

  11. RDF schema rdfs:label rdfs: Literal rdfs:Resource rdfs:Class rdfs:comment rdf:Property Provides the mechanism for declaring properties and also defining relationship between these properties and other resources S=rdfs:subclassOf t=rdf:type t s t t t t t t t t t t s t s s t t t t s t t rdfs:isDefinedBy rdfs:ConstraintResource rdfs:seeAlso rdfs:subPropertyOf rdfs:ContainerMembershipProperty rdfs:subCLassof rdfs:type rdfs:ConstraintProperty rdfs:range rdfs:domain

  12. Example rdf:class rdf:Resource xyz:Motor Vehicle xyz:Van s t t t t t s t s s s s t s xyz:Passenger Vehicle xyz:Mini Van xyz:Truck

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

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

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