Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

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Knowledge Graphs Lecture 2 - Basic Semantic Technologies 2.3 RDF Turtle Serialization

Prof. Dr. Harald Sack & Dr. Mehwish AlamFIZ Karlsruhe - Leibniz Institute for Information InfrastructureAIFB - Karlsruhe Institute of Technology

Autumn 2020

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

Knowledge GraphsLecture 2: Basic Semantic Technologies

2.1 How to Identify and Access Things

2.2 How to Represent Simple Facts with RDF

2.3 RDF Turtle Serialization

2.4 RDF Complex Data Structures

2.5 Model Building with RDFS

2.6 Logical Inference with RDF(S)

Excursion 1: RDFa - RDF and the Web

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology3<3>

URI

HTTP

address

RDF

reference

communication

WEBof Data

Basic Architecture of the Web of Data2. Basic Semantic Technologies / 2.3 RDF Turtle Serialization

[1]

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

#Lectures4Future

[2]

Resource Description Framework

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

RDF Serializations

● RDF comes with several different serialization formats:○ N-Triples, RDF/XML, JSON, Turtle, TriG, N-Quads, RDFa, ...

RDF/XML

N-Triples JSON-LDTurtle

TriG

N-Quads

extended bysupport for multiple graphs

We will use RDF/Turtle

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2. Basic Semantic Technologies / 2.3 RDF Turtle Serialization

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

● N-Triples Notation○ URIs/IRIs in angle brackets○ Literals in quotation marks○ Triple ends with a period

RDF Serializations

<http://dbpedia.org/resource/Greenhouse_effect> "1824"<http://dbpedia.org/ontology/discoveredIn>

<http://dbpedia.org/resource/Joseph_Fourier><http://dbpedia.org/ontology/discoverer>

<http://dbpedia.org/resource/Greenhouse_effect> <http://dbpedia.org/ontology/discoveredIn> "1824" .

<http://dbpedia.org/resource/Greenhouse_effect> <http://dbpedia.org/ontology/discoverer><http://dbpedia.org/resource/Joseph_Fourier> .

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2. Basic Semantic Technologies / 2.3 RDF Turtle Serialization

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

RDF Serializations

● Turtle (Terse RDF Triple Language) Notation○ extension of N-Triples

@prefix dbo: <http://dbpedia.org/ontology/> .@base <http://dbpedia.org/resource/> .

<Greenhouse_effect> dbo:discoveredIn "1824" .

<Greenhouse_effect> dbo:discoverer <Joseph_Fourier> .

RDF/Turtle allows shortcurts and abbreviations for readability

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<http://dbpedia.org/resource/Greenhouse_effect> "1824"<http://dbpedia.org/ontology/discoveredIn>

<http://dbpedia.org/resource/Joseph_Fourier><http://dbpedia.org/ontology/discoverer>

2. Basic Semantic Technologies / 2.3 RDF Turtle Serialization

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

● starting with N-Triples

<http://dbpedia.org/resource/Greenhouse_effect> <http://dbpedia.org/ontology/discoveredIn> "1824" .

<http://dbpedia.org/resource/Greenhouse_effect> <http://dbpedia.org/ontology/discoverer> <http://dbpedia.org/resource/Joseph_Fourier> .

@prefix dbo: <http://dbpedia.org/ontology/> .@base <http://dbpedia.org/resource/> .

<Greenhouse_effect> dbo:discoveredIn "1824" .

<Greenhouse_effect> dbo:discoverer <Joseph_Fourier> .

@prefix directive associates prefix-label with URI

@base directive provides URI to complement all relative URIs

RDF/Turtle

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<http://dbpedia.org/resource/Greenhouse_effect> "1824"<http://dbpedia.org/ontology/discoveredIn>

<http://dbpedia.org/resource/Joseph_Fourier><http://dbpedia.org/ontology/discoverer>

2. Basic Semantic Technologies / 2.3 RDF Turtle Serialization

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

● Abbreviating RDF Triples in Turtle

@prefix dbo: <http://dbpedia.org/ontology/> .@base <http://dbpedia.org/resource/> .

<Greenhouse_effect> dbo:discoveredIn "1824" ; dbo:discoverer <Joseph_Fourier> .

semicolon indicates that subsequent triples have the same subject (predicate list)

RDF/Turtle

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<http://dbpedia.org/resource/Greenhouse_effect> "1824"<http://dbpedia.org/ontology/discoveredIn>

<http://dbpedia.org/resource/Joseph_Fourier><http://dbpedia.org/ontology/discoverer>

2. Basic Semantic Technologies / 2.3 RDF Turtle Serialization

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

● Abbreviating RDF Triples in Turtle

http://dbpedia.org/resource/Greenhouse_effect http://dbpedia.org/category/Athmospheredct:subject

@prefix dct: <http://purl.org/dc/terms/> .@prefix dbc: <http://dbpedia.org/category/> .@base <http://dbpedia.org/resource/> .

<Greenhouse_effect> dct:subject dbc:Athmosphere , dbc:Climate_change , dbc:Athmospheric_radiation .

comma indicates that subsequent triples have same subject and property (object list)

http://dbpedia.org/category/Climate_change

http://dbpedia.org/category/Athmospheric_radiation

dct:subject

dct:subject

RDF/Turtle

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2. Basic Semantic Technologies / 2.3 RDF Turtle Serialization

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

● Typed Literals

http://dbpedia.org/resource/Carbon_Dioxide "-78.5"^^xsd:doubledbo:sublimationTemperature

@prefix dbo: <http://dbpedia.org/ontology/> .@prefix xsd: <http://www.w3c.org/2001/XMLSchema#> .@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .@base <http://dbpedia.org/resource/> .

<Carbon_Dioxide> dbo:sublimationTemperature "-78.5"^^xsd:double ; dbo:molarMass "44.009"^^xsd:double ; dbo:discovered "1640-00-00"^^xsd:date ; rdfs:label "Carbon Dioxide"@en .

"44.009"^^xsd:double

"1640-00-00"^^xsd:date

dbo:molarMass

rdfs:label

"Carbon Dioxide"@en

dbo:discovered

RDF/Turtle

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2. Basic Semantic Technologies / 2.3 RDF Turtle Serialization

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

● Multi Valued Relations○ CO2 was discovered / rediscovered

by two scientists at different times.○ How to model this in RDF?

○ Problem: unique association

RDF/Turtle

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Carbon_Dioxide Jan_Baptist_van_Helmont dbo:discoverer

"1640-00-00"^^xsd:date

dbo:discoveredIn

Joseph_Black

dbo:discoverer

dbo:discoveredIn

"1750-00-00"^^xsd:date

2. Basic Semantic Technologies / 2.3 RDF Turtle Serialization

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

● Multi Valued Relations○ Blank Nodes (Bnodes) can be

introduced to represent multi- valued relationships.

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

RDF/Turtle

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Jan_Baptist_van_Helmontdbo:discovery

"1640-00-00"^^xsd:date

Joseph_Black

dbo:discoveredIn

dbo:discovery

dbo:discoverer

"1750-00-00"^^xsd:date

Carbon_Dioxide

dbo:discoveredIn

dbo:discoverer

2. Basic Semantic Technologies / 2.3 RDF Turtle Serialization

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

@prefix dbo: <http://dbpedia.org/ontology/> .@prefix xsd: <http://www.w3c.org/2001/XMLSchema#> .@base <http://dbpedia.org/resource/> .

[] dbo:discoverer <Jan_Baptist_van_Helmont> ; dbo:discoveredIn "1640-00-00"^^xsd:date .

anonymous blank node as subject

RDF/Turtle

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Jan_Baptist_van_Helmont

"1640-00-00"^^xsd:date

dbo:discoveredIn

dbo:discoverer

2. Basic Semantic Technologies / 2.3 RDF Turtle Serialization

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

@prefix dbo: <http://dbpedia.org/ontology/> .@prefix xsd: <http://www.w3c.org/2001/XMLSchema#> .@base <http://dbpedia.org/resource/> .

<Carbon_Dioxide> dbo:discovery [ dbo:discoverer <Jean_Baptist_van_Helmont> ; dbo:discoveredIn "1640-00-00"^^xsd:date ] , [ dbo:discoverer <Joseph_Black> ; dbo:discoveredIn "1750-00-00"^^xsd:date ] .

nested anonymous blank nodes

RDF/Turtle

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Jan_Baptist_van_Helmontdbo:discovery

"1640-00-00"^^xsd:date

Joseph_Black

dbo:discoveredIn

dbo:discovery

dbo:discoverer

"1750-00-00"^^xsd:date

Carbon_Dioxide

dbo:discoveredIn

dbo:discoverer

2. Basic Semantic Technologies / 2.3 RDF Turtle Serialization

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

@prefix dbo: <http://dbpedia.org/ontology/> .@prefix xsd: <http://www.w3c.org/2001/XMLSchema#> .@base <http://dbpedia.org/resource/> .

<Carbon_Dioxide> dbo:discovery _:ID1, _:ID2 .

_:ID1 dbo:discoverer <Jan_Baptist_van_Helmont> ; dbo:discoveredIn "1640-00-00"^^xsd:date .

_:ID2 dbo:discoverer <John_Black> ; dbo:discoveredIn "1750-00-00"^^xsd:date .

dereferenceable blank nodescan only be referenced from inside a document / graph

RDF/Turtle

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Jan_Baptist_van_Helmontdbo:discovery

"1640-00-00"^^xsd:date

Joseph_Black

dbo:discoveredIn

dbo:discovery

dbo:discoverer

"1750-00-00"^^xsd:date

ID1Carbon_Dioxide

ID2

dbo:discoveredIn

dbo:discoverer

2. Basic Semantic Technologies / 2.3 RDF Turtle Serialization

Information Sertvice Engineering , Prof. Dr. Harald Sack & Dr. Maria Koutraki, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

RDF Complex Data

Structures

Next Lecture... [3]

Knowledge Graphs 2020 , Prof. Dr. Harald Sack & Dr. Mehwish Alam, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & Karlsruhe Institute of Technology

Picture References:● [1] Benjamin Nowack, The Semantic Web - Not a Piece of cake…, at bnode.org, 2009-07-08 , [CC BY 3.0]

http://bnode.org/blog/2009/07/08/the-semantic-web-not-a-piece-of-cake

● [2] The Green House Effect, A loose necktie [CC BY-SA]https://commons.wikimedia.org/wiki/File:Greenhouse-effect-t445.svg

● [3] The British Museum: the reading room under construction. Wood engraving by J. Brown after C. W. Sheeres, 1855., The Wellcome Collection, [CC-BY-4.0]https://upload.wikimedia.org/wikipedia/commons/a/ad/The_British_Museum%3B_the_reading_room_under_construction._Woo_Wellcome_V0013519.jpg

Knowledge Graphs2. Basic Semantic Technologies / 2.3 RDF Turtle Serialization