OpenHPI 2.5 - How to Represent Facts - RDF(4)

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Dr. Harald Sack

Hasso Plattner Institute for IT Systems Engineering

University of Potsdam

Spring 2013

Semantic Web Technologies

Lecture 2: Semantic Web - Basic Architecture I05: How to Represent Facts? - RDF(4)

Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam

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Lecture 2: Semantic Web - Basic Architecture I

Open HPI - Course: Semantic Web Technologies


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05 How to Represent Facts? - RDF (4)Open HPI - Course: Semantic Web Technologies - Lecture 2: Semantic Web Basic Architecture I


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05 How to Represent Facts? - RDF (4)Open HPI - Course: Semantic Web Technologies - Lecture 2: Semantic Web Basic Architecture I

Reification&RDF Data Integration


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Resource Description Framework


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„My dear Watson,...I suppose that the Gardenerhas killed the Butler!“


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RDF-Reification• RDF permits interleaving of statements,

i.e. to make statements about statements

• Example:

„My dear Watson,...I suppose that the Gardenerhas killed the Butler!“


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RDF-Reification• RDF permits interleaving of statements, i.e. to make statements about

statements

• Example:• Sherlock Holmes supposes that the Gardener has killed the Butler

•Part 1: The Gardener has killed the Butler

•Part 2: Sherlock Holmes supposes

exv:Gardener exv:hasKilled exv:Butler .

exv:SherlockHolmes exv:supposes ???? .


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RDF-Reification• rdf:Statement

defines an RDF Statement, consisting of Subject, Predicate and Object

• rdf:subject - the described resource

• rdf:predicate - the original property

• rdf:object - the value of the property


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RDF-Reification

:SherlockHolmes

ex:supposes

:StatementOnGardener

:Gardener

ex:hasKilled

:Butler

rdf:subject

rdf:predicate

rdf:object

Sherlock Holmes supposes that the Gardener has killed the Butler


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RDF-Reification

:SherlockHolmes

ex:supposes

:StatementOnGardener

:Gardener

ex:hasKilled

:Butler

rdf:subject

rdf:predicate

rdf:object

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .@prefix ex: <http://example.org/Crime#> .@prefix : <http://example.org/> .

:SherlockHolmes ex:supposes :StatementOnGardener .:StatementOnGardener a rdf:Statement ; rdf:subject :Gardener ; rdf:predicate ex:hasKilled ; rdf:object :Butler .

http://www.w3.org/1999/02/22-rdf-syntax-ns#

http://www.w3.org/1999/02/22-rdf-syntax-ns#

http://example.org

http://example.org

http://example.org

http://example.org


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RDF-Reification• Is Reification really necessary?

• Modeling data provenance

• Formalizing statements about Reliability (Trust)

• Definition of Metadata about Statements (Assertions, Statements)

• for (general) knowledge representation (Ontologie Construction):

• Transformation of Relations into Classes

•But be careful: Reification causes type conflicts (classes, individuals, statements)


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RDF and Data Integration


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• Simple Example: Bibliography Database

ID Author Title Publisher Year

ISBN 0-00-651409-X HS-123 WWW S-001 2004

ID Name Homepage

HS-123 Harald Sack http://hpi-web.de/HaraldSack.html

ID Publisher Location

S-001 Springer Heidelberg


Books

Authors

Publishers

http://hpi-web.de/HaraldSack.html



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ISBN 0-00-651409-X

WWW

2004

a:title

a:year

Springer

Heidelberg

a:publishername

a:publisherlocation

a:publisher

Harald Sack


a:authorname

a:authorhomepage

a:author

• Database export into a set of relations





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ISBN 0-00-651409-X

u:author

Harald Sack

u:name

http://.../paper

u:cites

Very important paper

u:title


ISBN 0-00-651409-X

WWW

2004

a:title

a:year

Springer

Heidelberg

a:publishername

a:publisherlocation

a:publisher

Harald Sack


a:authorname

a:authorhomepage

a:author




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ISBN 0-00-651409-X

WWW

2004

Springer

Heidelberg

Harald Sack


ISBN 0-00-651409-X

u:author

Harald Sack

u:name

http://.../paper

u:cites


u:title

a:title

a:year

a:publishername

a:publisherlocation

a:publisher

a:authorname

a:authorhomepage

a:author





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WWW

2004

Springer

Heidelberg

Harald Sack


u:author

Harald Sack

u:name

http://.../paper

u:cites


ISBN 0-00-651409-X

u:title

a:title

a:year

a:publishername

a:publisherlocationa:publisher

a:authorname

a:authorhomepage

a:author





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RDF - a Resume

RDF Model -- Summary

• An RDF Model is a set of RDF statements

• Statement := (subject, property, object)

• Subject is a resource

• Property is a resource

• Object is either a resource or a literal


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SO ... WE NEED A WAY TO DEFINE RDF SCHEMATA FORCLASSES AND RELATIONS ?!

06 How to Model Classes and Relations? - RDFS

Open HPI - Course: Semantic Web Technologies - Lecture 2: Semantic Web Basic Architecture I

OpenHPI 2.5 - How to Represent Facts - RDF(4)

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