OpenHPI 2.4 - How to Represent Facts - RDF(3)

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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 I04: How to Represent Facts? - RDF(3)

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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04 How to Represent Facts? - RDF (3)Open HPI - Course: Semantic Web Technologies - Lecture 2: Semantic Web Basic Architecture I


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Blank Nodes and Lists


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Resource Description Framework

Multi Valued Relations and Blank Nodes• Example:

• A lecture takes place twice a week in two different rooms

• How to model this in RDF?


http://hpi-web.de/Lecture#hasName

http://hpi-web.de/ws1213#swt

http://hpi-web.de/LehrVeranstaltung#


http://hpi-web.de/WS0809/semanticweb



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http://hpi-web.de/Lecture#hasRoom

http://hpi-web.de/Lecture#hasDate

HS3

Tue 13.30-15.00









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HS3

Tue 13.30-15.00



H-1.52

Wed 13.30-15.00









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Problem: not unique





HS3

Tue 13.30-15.00



H-1.52

Wed 13.30-15.00









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hpi-lv:hasRoom


Semantic Web Technologieshpi-lv:hasName

HS3

Tue 13.30-15.00

hpi-lv:hasDate

H-1.52

Wed 13.30-15.00

hpi-lv:hasRoom

hpi-lv:hasDate

hpi-lv:takesPlace

hpi-lv:takesPlace




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Blank Nodes• Blank Nodes (Bnodes) can be introduced to represend multi valued

relationships

• Blank Nodes can be introduced for resources that don‘t need a name(auxiliary nodes)

hpi-lv:hasRoom



hpi-lv:hasName

HS3

Tue 13.30-15.00

hpi-lv:hasDate

hpi-lv:takesPlace




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Anonymous Blank Nodes

hpi-lv:hasRoom



hpi-lv:hasName

HS3

Tue 13.30-15.00

hpi-lv:hasDate

hpi-lv:takesPlace

<xml version=“1.0“ encoding=“utf-8“><rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#“ xmlns:hpi-lv=“http://hpi-web.de/Lecture#“ >

<rdf:Description rdf:about=“http://hpi-web.de/ws1213#swt“> <hpi-lv:takesPlace rdf:parseType=“Resource“/> <hpi-lv:hasDate>Die, 13.30-15.00</hpi-lv:hasDate> <hpi-lv:hasRoom>HS3</hpi-lv:hasRoom> </hpi-lv:takesPlace> </rdf:Description>



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





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Anonymous Blank Nodes

hpi-lv:hasRoom



hpi-lv:hasName

HS3

Tue 13.30-15.00

hpi-lv:hasDate

hpi-lv:takesPlace

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .@prefix hpi-lv: <http://hpi-web.de/Lecture#> .

<http://hpi-web.de/ws1213#swt> hpi-lv:takesPlace [ hpi-lv:hasDate “Tue 13.30-15.00“; hpi-lv:hasRoom “HS3“ ] .







http://hpi-web.de/

http://hpi-web.de/


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Dereferencable Blank Nodes

hpi-lv:hasRoom



hpi-lv:hasName

HS3

Tue 13.30-15.00

hpi-lv:hasDate

ID1

hpi-lv:takesPlace

<rdf:Description rdf:about=“http://hpi-web.de/ws1213#swt“> <hpi-lv:takesPlace rdf:nodeID=“ID1“/> <rdf:Description>

<rdf:Description rdf:nodeID=“ID1“> <hpi-lv:hasDate>Tue 13.30-15.00</hpi-lv:hasDate> <hi-lv:hasRoom>HS3<hpi-lv:hasRoom> </rdf:Description></rdf:RDF>




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Dereferencable Blank Nodes

hpi-lv:hasRoom



hpi-lv:hasName

HS3

Tue 13.30-15.00

hpi-lv:hasDate

ID1

hpi-lv:takesPlace

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .@prefix hpi-lv: <http://hpi-web.de/Lecture#> .

<http://hpi-web.de/ws1213#swt> hpi-lv:takesPlace _:ID1 .

_:ID1 hpi-lv:hasDate “Tue 13.30-15.00“; hpi-lv:hasRoom “HS3“ .







http://hpi-web.de/

http://hpi-web.de/


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Lists• General Data structure to enumerate any resoures or literals

• Only shortcuts, no additional semantic expressivity

• Distinguish between

• Container open list, i.e. extension (new entries) possible

• Collectionsclosed list, i.e. no extension possible


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RDF Container

rdf:type

rdf:Seq

hpi-lv:hasParticipants

http://hpi-web.de/SchmidtJoseph

http://hpi-web.de/SchulzeEgon

http://hpi-web.de/MuellerFranz

http://hpi-web.de/BurgerAntonrdf:_1


rdf:_2

rdf:_3

rdf:_4

@prefix hpi-lv: <http://hpi-web.de/Lecture#> .@prefix rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns#> .

http://hpi-web.de/semanticweb/







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RDF Container


<rdf:Description rdf:about=“http://hpi-web.de/ws1213#swt“> <lv:hasParticipants> <rdf:Seq> <rdf:li rdf:resource=“http://hpi-web.de/BurgerAnton“ /> <rdf:li rdf:resource=“http://hpi-web.de/MuellerFranz“ /> <rdf:li rdf:resource=“http://hpi-web.de/SchmidtJoseph“ /> <rdf:li rdf:resource=“http://hpi-web.de/SchulzeEgon“ /> </rdf:Seq> </lv:hasParticipants> </rdf:Description>






http://hpi-web.de/semanticweb


RDF-Container• the root node of the container is

assigned a container-typ via rdf:type

• rdf:Bagunordered set of elements,there is no given order of elements

• rdf:Seqordered set of elements,

• rdf:Altdefines alternatives of elements only one element of the given alternatives is relevant for the application


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RDF Container

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .@prefix lv: <http://hpi-web.de/Lecture#> .@base <http://hpi-web.de/>

:swt lv:hasParticipants [ a rdf:Seq; rdf:_1 <BurgerAnton>; rdf:_2 <MuellerFranz>; rdf:_3 <SchmidtJoseph>; rdf:_4 <SchulzeEgon> . ] .





http://hpi-web.de/

http://hpi-web.de/

RDF-Collection


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rdf:nil

lv:hasParticipants rdf:first

rdf:rest

http://hpi-web.de/SchmidtJoseph

http://hpi-web.de/SchulzeEgon


http://hpi-web.de/BurgerAnton

List is splitted recursively in Head (first) and Tail (rest).


rdf:rest

rdf:rest

rdf:rest

rdf:first

rdf:first

rdf:first










RDF-Collection

<rdf:Description rdf:about=“http://hpi-web.de/ws1213#swt“> <lv:hasParticipant rdf:parseType=“Collection“> <rdf:Description rdf:about=“http://hpi-web.de/BurgerAnton“ /> <rdf:Description rdf:about=“http://hpi-web.de/MuellerFranz“ /> <rdf:Description rdf:about=“http://hpi-web.de/SchmidtJoseph“ /> <rdf:Description rdf:rabout=“http://hpi-web.de/SchulzeEgon“ /> </lv:hasParticipant> </rdf:Description>


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RDF-Collection


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:swt lv:hasParticipant [ rdf:first <BurgerAnton>; rdf:rest [ rdf:first <MuellerFranz>; rdf:rest [ rdf:first <SchmidtJoseph>; rdf:rest [ rdf:first <SchulzeEgon>; rdf:rest rdf:nil .] ] ] ] .






http://hpi-web.de/

http://hpi-web.de/

RDF-Collection


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:swt lv:hasParticipant ( <BurgerAnton> <MuellerFranz> <SchmidtJoseph> <SchulzeEgon>) .






http://hpi-web.de/

http://hpi-web.de/


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Reification

Documents

OpenHPI 2.4 - How to Represent Facts - RDF(3)