Post on 19-Jul-2020
transcript
Semantic Data
Chapter 3 : The semantic web
resource description framework
Jean-Louis Binot
19/02/2020Semantic Data1
Course content outline
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Sources and recommended readings
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Agenda
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Why not HTML or XML ?2
Resource description framework3
The semantic web stack1
RDF Schema4
The semantic web standards (W3C consortium)
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Agenda
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Why not HTML or XML ?2
Resource description framework3
The semantic web stack1
RDF Schema4
Why not just HTML ?
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Might XML be a better solution ?
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Why not just XML : an example
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lecturer)
Agenda
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Why not HTML or XML ?2
Resource description framework3
The semantic web stack1
RDF Schema4
Basic ideas of the Resource Description Framework (RDF)
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Properties
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Statements
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The RDF data model is based on directed labelled graphs
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RDF serialization - Turtle
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Namespaces and reference vocabularies
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Some usual vocabularies
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Namespaces ./.
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Types of triple elements
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Example with URIs and literals
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Literals and datatypes
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Blank nodes
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Use of blank nodes for structured data
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Instances and typing
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Syntactic sugar
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The Mona Lisa example in Turtle
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Reification
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Syntaxes for expressing RDF graphs
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The Mona Lisa example in RDF/XML
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RDFa (RDF in HTML attributes)
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A review snippet from Google
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Triples generated from the review snipet
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Semantics of RDF graphs
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∃ ∧
Semantics of RDF graphs ./.
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The interpolation lemma
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Interpolation lemma: example
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Agenda
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Why not HTML or XML ?2
Resource description framework3
The semantic web stack1
RDF Schema4
Motivation for RDFS
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Example of a simple RDFS ontology
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RDFS
RDFS basic ideas
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http://www.w3.org/2000/01/rdf-schema#>
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RDFS main constructs
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Construct (construct type) Syntactic form Description
Class (a class) C rdf:type rdfs:Class C (a resource) is an RDF class
Property (a class) P rdf:type rdf:Property P (a resource) is an RDF property
type (a property) I rdf:type C I (a resource) is an instance of C (a class)
subClassOf (a property) C1 rdfs:subClassOf C2 C1 (a class) is a subclass of C2 (a class)
subPropertyOf (a property) P1 rdfs:subPropertyOf P2 P1 (a property) is a sub-property of P2 (a property)
domain (a property) P rdfs:domain C domain of P (a property) is C (a class)
range (a property) P rdfs:range C range of P (a property) is C (a class)
Defining classes and instances
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Defining classes and instances ./.
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More on RDFS classes
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Subsumption
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Class hierarchy and instances
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Example of hierarchy with corresponding triples
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Defining Properties
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Range and domain of properties
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Range and domain inference rules
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Specialization of properties
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Complex cases for range and domain of properties
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Multiple range or domain statements
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RDFS Semantics
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Revisiting the example from chapter 1
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(example after Paulheim, Semantic Web Technologies)
Revisiting the example from chapter 1
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(example after Paulheim, Semantic Web Technologies)
More on the limitations of RDFS
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(after Antoniou and Van Harmelen 2004)
Summary
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Annex : RDF/RDFS entailment patterns
If S contains: then S RDF(S)_entails :
rdfD1 a p "v"^^d . a p _:b . _b rdf:type d .
rdfD2 a p b . p rdf:type rdf:Property .
rdfs1 any IRI a in D a rdf:type rdfs:Datatype .
rdfs2p rdfs:domain x .
a p b .a rdf:type x .
rdfs3p rdfs:range x .
a p b .b rdf:type x .
rdfs4a a p b . a rdf:type rdf:Resource .
rdfs4b a p b . b rdf:type rdf:Resource .
rdfs5p rdfs:subPropertyOf q .
q rdfs:subPropertyOf r .p rdfs:subPropertyOf r .
rdfs6 a rdf:type rdf:Property . a rdfs:subPropertyOf a .
rdfs7rdfs:subPropertyOf q .
a p b.a q b .
rdfs8 c rdf:type rdfs:Class . c rdfs:subClassOf rdf:Resource .
rdfs9c rdfs:subClassOf d .
a rdf:type c.a rdf:type d .
rdfs10 c rdf:type rdfs:Class . c rdfs:subClassOf c .
rdfs11c rdfs:subClassOf d .
d rdfs:subClassOf e .c rdfs:subClassOf e .
rdfs12 rdf:type rdfs:ContainerMembershipProperty . p rdfs:subPropertyOf rdfs:member .
rdfs13 d rdf:type rdfs:Datatype . d rdfs:subClassOf rdfs:Literal .
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References
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THANK YOU
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