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![Page 1: Resource Description Framework Building the Semantic Web CS 431 – 20040308 Carl Lagoze – Cornell University Acknowledgements: Eric Miller Dieter Fensel.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d625503460f94a44dda/html5/thumbnails/1.jpg)
Resource Description FrameworkBuilding the Semantic Web
CS 431 – 20040308Carl Lagoze – Cornell University
Acknowledgements:Eric MillerDieter Fensel
![Page 2: Resource Description Framework Building the Semantic Web CS 431 – 20040308 Carl Lagoze – Cornell University Acknowledgements: Eric Miller Dieter Fensel.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d625503460f94a44dda/html5/thumbnails/2.jpg)
Motivating the “Semantic Web”
M. Doe illustrated the book “Best
Stories”Mary Doe
animated the cartoon “Best Stories – the
movie”
Illustration is a type of
contribution
animation is a type of
contribution
M. Doe and Mary Doe are
pseudonyms forSusan Mann
Show me the works to which Susan
Mann contributed?
Cartoons and Books are types
of Works
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Components of the Semantic Web
![Page 4: Resource Description Framework Building the Semantic Web CS 431 – 20040308 Carl Lagoze – Cornell University Acknowledgements: Eric Miller Dieter Fensel.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d625503460f94a44dda/html5/thumbnails/4.jpg)
Modeling & Encoding Metadata Components: RDF
• RDF (Resource Description Format)• Provides enabling technology for richly-
structured metadata– Support for and integration of multiple independent
metadata vocabularies
• Rich data model supporting notions of distinct entities and properties– Formal model with basis in logic
• Primitives permit semantic inferencing • Expressible in machine readable manner (e.g.,
XML)
![Page 5: Resource Description Framework Building the Semantic Web CS 431 – 20040308 Carl Lagoze – Cornell University Acknowledgements: Eric Miller Dieter Fensel.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d625503460f94a44dda/html5/thumbnails/5.jpg)
RDF Components
• Formal data model• Syntax for interchange of data• Schema Type system (schema model)• Syntax for machine-understandable schemas• Query and profile protocols
• Ontologies layered on top
![Page 6: Resource Description Framework Building the Semantic Web CS 431 – 20040308 Carl Lagoze – Cornell University Acknowledgements: Eric Miller Dieter Fensel.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d625503460f94a44dda/html5/thumbnails/6.jpg)
RDF Data Model
• Provides underlying structural foundation for the expression of application (instance) data models– for consistent encoding, exchange and processing of
metadata– Provides for a basis for interoperability
• Individual communities can then define and express semantics on the basic model
• Model is distinct from the syntax for expressing it (1-to-many relationship)
![Page 7: Resource Description Framework Building the Semantic Web CS 431 – 20040308 Carl Lagoze – Cornell University Acknowledgements: Eric Miller Dieter Fensel.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d625503460f94a44dda/html5/thumbnails/7.jpg)
RDF Data Model
• Directed labeled graphs• Model elements
– Resource– Property– Value– Statement– Containers
![Page 8: Resource Description Framework Building the Semantic Web CS 431 – 20040308 Carl Lagoze – Cornell University Acknowledgements: Eric Miller Dieter Fensel.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d625503460f94a44dda/html5/thumbnails/8.jpg)
RDF Model Primitives
ResourceProperty
ValueResource
Statement
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Simple Example
ResourceAuthor
“Eric”
![Page 10: Resource Description Framework Building the Semantic Web CS 431 – 20040308 Carl Lagoze – Cornell University Acknowledgements: Eric Miller Dieter Fensel.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d625503460f94a44dda/html5/thumbnails/10.jpg)
RDF Syntax
• RDF Model defines a formal relationships among resources, properties and values
• Syntax is required to...– Store instances of the model into files– Communicate files from one application to another
• XML is one well-supported syntax• There are syntax alternatives
– Relational databases– Triple Stores– N3 Notation
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RDF Model Example #1
URI:R“CIMI Presentation”
Title
Creatordc:
dc:
“Eric Miller”
![Page 12: Resource Description Framework Building the Semantic Web CS 431 – 20040308 Carl Lagoze – Cornell University Acknowledgements: Eric Miller Dieter Fensel.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d625503460f94a44dda/html5/thumbnails/12.jpg)
RDF Syntax Example #1
URI:R“CIMI Presentation”
Title
Creatordc:
dc:
“Eric Miller”
<RDF xmlns = “http://www.w3.org/TR/WD-rdf-syntax#” xmlns:dc = “http://purl.org/dc/elements/1.0/”> <Description about = “URI:R”> <dc:Title> CIMI Presentation </dc:Title> <dc:Creator> Eric Miller </dc:Creator> </Description></RDF>
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“Eric Miller”
RDF Model Example #2
URI:R
URI:ERIC
“[email protected]”“Eric Miller”
“OCLC”
bib:Emailbib:Affbib:Name
URI:OCLC
“CIMI Presentation”Title
Creatoroa:
dc:
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<RDF xmlns = “http://www.w3.org/TR/WD-rdf-syntax#” xmlns:dc = “http://purl.org/dc/elements/1.0/” xmlns:bib = “http://www.bib.org/persons#” xmlns:oa = “http://www.agents.org/ag”> <Description about = “URI:R”> <dc:Title> CIMI Presentation </dc:Title> <oa:Creator> <Description> <bib:Name> Eric Miller </bib:Name> <bib:Email> [email protected] </bib:Email> <bib:Aff resource = “http://www.oclc.org” /> </Description> </oa:Creator> </Description></RDF>
RDF Syntax Example #2
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“Eric Miller”
RDF Model Example #3Reification
URI:R
URI:ERIC
“[email protected]”“Eric Miller”
“OCLC”
bib:Emailbib:Affbib:Name
URI:OCLC
“CIMI Presentation”Title
Creator admin:By
admin:On
“LOC”
“03-09-99”
admin:For“...”
dc:
dc:
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RDF Containers
• Permit the aggregation of several values for a property
• Express multiple aggregation semantics– unordered– sequential or priority order– alternative
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RDF Containers
• Permit the aggregation of several values for a property
• Express multiple aggregation semantics– unordered– sequential or priority order– alternative
![Page 18: Resource Description Framework Building the Semantic Web CS 431 – 20040308 Carl Lagoze – Cornell University Acknowledgements: Eric Miller Dieter Fensel.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d625503460f94a44dda/html5/thumbnails/18.jpg)
RDF Containers
• Bag– unordered grouping
• Sequence– ordered grouping
• Alternatives– alternate values
• need to choose
– at least one value– first value is default or preferred value
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RDF - Bag
• Unordered group• “Carl Lagoze and Stuart Weibel are co-authors”
<BIB:Author> <Bag> <li> Carl Lagoze </li> <li> Stuart Weibel </li></Bag></BIB:Author>
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RDF - Sequence
• Ordered or priority group• “Carl Lagoze is primary author and Stuart Weibel is
second author”
<BIB:Author> <Seq> <li> Carl Lagoze </li> <li> Stuart Weibel </li></Seq></BIB:Author>
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RDF - Alt
• Client chooses one of several values• First value is default• “The distance is 15 kilometers or 9.3 miles”
<DC:Coverage> <Alt> <li> 15KM </li> <li> 9.3M </li></Alt></DC:Coverage>
![Page 22: Resource Description Framework Building the Semantic Web CS 431 – 20040308 Carl Lagoze – Cornell University Acknowledgements: Eric Miller Dieter Fensel.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d625503460f94a44dda/html5/thumbnails/22.jpg)
RDF meta-model
• RDF basic types– rdf:Resource – everything that can be identified (with a
URI)– rdf:Property – specialization of a resource expressing a
binary relation between two resources– Rdf:type – predefined property to express that subject of
property is considered to be an instance of that category or class defined by the value of the property
– rdf:statement – a triple with properties rdf:subject, rdf:predicate, rdf:object
• An RDF statement is a triple consisting of a resource (subject), a property and a second resource (object)– (:s :p :o)
• Expressible also as binary relations– P(S,O) – e.g., Title(R, “War & Peace”)
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RDF triple model
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RDF statements and basic types
WYA
creator
DigitalLibraries
rdf:s
ubje
ct
rdf:p
red
icate
rdf:object
rdf:statement
rdf:property
![Page 25: Resource Description Framework Building the Semantic Web CS 431 – 20040308 Carl Lagoze – Cornell University Acknowledgements: Eric Miller Dieter Fensel.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d625503460f94a44dda/html5/thumbnails/25.jpg)
Reification – Statements about statements
“CL says ‘WYA wrote Digital Libraries’”
WYA
creator
DigitalLibraries
rdf:s
ubje
ct
rdf:p
red
icate
rdf:object
rdf:statement
rdf:property
CLassertedBy