Linked Data tutorial at Semtech 2012

www.capsenta.com 1

Linked DataJuan F. Sequeda – Daniel P. MirankerCapsenta

Semantic Tech & Business Conference 2012

June 4, 2012

Outline

Part 1: Introduction to Linked Data

Part 2: Linked Data Principles

Part 3: Linked Data Architectures

Part 4: Linked Enterprise Data

www.capsenta.com June 4, 2012 2

3

Part 1:Introduction to

Linked Data

June 4, 2012 www.capsenta.com

The Web is a Data Shredder

Structured Data

Unstructured Data

Thanks Martin Hepp

June 4, 2012 www.capsenta.com 4

The Web of Documents

Search

Crawler

Search Engine


What would we like?

Make it easy for computers/software to find THINGS

Do you SEARCH or do you FIND?


www.capsenta.com 7

Search forFootball Players who went to the

University of Texas at Austin, played for the Dallas Cowboys as Cornerback

June 4, 2012

www.capsenta.com 11

Why can’t we just FIND it…

June 4, 2012

www.capsenta.com 14

Guess how I FOUND out?

June 4, 2012

On a Semantic Web

Besides publishing documents on the webwhich computers can’t understand easily

Let’s publish on the web something that computers can understand

DATAJune 4, 2012 www.capsenta.com 15

www.capsenta.com 16

The Semantic Web is a web of data

The current web is a web of documents

June 4, 2012

www.capsenta.com 17

But wait… doesn’t the web already have data?

June 4, 2012

Current Data on the Web

Relational Databases

APIs

XML

CSV

XLS

…

Can’t computers and applications already consume that data on the web?


www.capsenta.com 19

Yes! But it is all in different formats and data models!

June 4, 2012

www.capsenta.com 20

This makes it hard to integrate data

June 4, 2012

www.capsenta.com 21

The data in different data sources aren’t linked

June 4, 2012

www.capsenta.com 22

For example, how do I state that the Juan Sequeda in Facebook is the

same as Juan Sequeda in Twitter

June 4, 2012

www.capsenta.com 23

Or if I create a mashup from different services, I have to learn different APIs

and I get different formats of data back

June 4, 2012

Data is Siloed


www.capsenta.com 25

Wouldn’t it be great if we had a standard way of publishing data

on the Web?

June 4, 2012

www.capsenta.com 26

We have a standardized way of publishing documents on the web,

right?HTML

June 4, 2012

www.capsenta.com 27

Then why can’t we have a standard way of publishing data

on the Web?

June 4, 2012

www.capsenta.com 28

Good question! And the answer is YES. There is!

RDF

June 4, 2012

Resource Description Framework (RDF)

Data Model = a way to model datai.e. Relational databases use relational data model

RDF is a graph data model


RDF is a Graph

<JuanSequeda> <firstName> “Juan”<JuanSequeda> <lastName> “Sequeda”<JuanSequeda> <livesIn> “Austin”<JuanSequeda> <knows> <DanielMiranker>..<DanielMiranker> <firstName> “Daniel”<DanielMiranker> <lastName> “Miranker”<DanielMiranker> <livesIn> “Austin”


RDF can be serialized in different ways

RDF/XML

RDFa (RDF in HTML)

N3

Turtle

JSON


RDFa


RDF/XML


RDF/N-triples


RDF/Turtle


www.capsenta.com 37

So does that mean that I have to publish my data in RDF now?

June 4, 2012

www.capsenta.com 38

You don’t have to… but we would like you to

June 4, 2012

www.capsenta.com 39

An example

June 4, 2012

Document on the Web


Databases back up documents

Isbn Title Author PublisherID ReleasedData

978-0-596-15381-6

Programming the Semantic Web

Toby Segaran

1 July 2009

… … … … …

PublisherID

PublisherName

1 O’Reilly Media

… …

This is a THING:A book title “Programming the Semantic Web” by Toby Segaran, …

THINGS have PROPERTIES:A Book as a Title, an author, …


Lets represent the data in RDF

book

Programming the Semantic

Web

978-0-596-15381-6

Toby Segaran

Publisher O’Reilly

title

name

author

publisher

isbn

Isbn Title Author PublisherID ReleasedData

978-0-596-15381-6

Programming the Semantic Web

Toby Segaran

1 July 2009

PublisherID

PublisherName

1 O’Reilly Media


www.capsenta.com 43

Remember that we are on the web

Everything on the web is identified by a URI

June 4, 2012

And now let’s link the data to other data

http://…/

isbn978


Web

978-0-596-15381-6

Toby Segaran

http://…/

publisher1

O’Reilly

title

name

author

publisher

isbn


And now consider the data from Revyu.com

http://…/

isbn978

http://…/

review1

Awesome Book

http://…/

reviewer

Juan Sequeda

hasReview

reviewer

description

name


Let’s start to link data

http://…/

isbn978


Web

978-0-596-15381-6

Toby Segaran

http://…/

publisher1

O’Reilly

title

name

author

publisher

isbn

http://…/

isbn978

owl:sameAs

http://…/

review1

Awesome Book

http://…/

reviewer

Juan Sequeda

hasReview

hasReviewer

description

name


Juan Sequeda publishes data too

http://juansequeda.com/id

livesIn

Juan Sequedaname

http://dbpedia.org/Austin


Let’s link more datahttp://

…/isbn978

http://…/

review1

Awesome Book

http://…/reviewer

Juan Sequeda


hasReview

hasReviewer

description

name

sameAs

livesIn

Juan Sequedaname



And more

http://…/isbn978


Web

978-0-596-15381-6

Toby Segaran

http://…/publisher1 O’Reilly

title

name

author

publisher

isbn

http://…/

isbn978

owl:sameAs

http://…/

review1

Awesome Book

http://…/

reviewer

Juan Sequeda


hasReview

hasReviewer

description

name

owl:sameAs

livesIn

Juan Sequedaname



www.capsenta.com 50

Data on the Web that is in RDF and is linked to other RDF data is

LINKED DATA

June 4, 2012

www.capsenta.com 51

Linked Data makes the web appear as ONE

GIANTHUGE

GLOBAL

DATABASE!

June 4, 2012

www.capsenta.com 52

I can query a database with SQL. Is there a way to query Linked Data

with a query language?

June 4, 2012

www.capsenta.com 53

Yes! There is actually a standardize language for that

SPARQL

June 4, 2012

www.capsenta.com 54

FIND all the reviews on the book “Programming the Semantic Web”

by people who live in Austin

June 4, 2012

SELECT ?review ?commentWHERE { isbn:978 ex:hasReview ?review . ?review ex:description ?comment . ?review ex:hasReviewer ?person . ?person ex:lives dbpedia:Austin .}

SPARQL


http://…/isbn978


Web

978-0-596-15381-6

Toby Segaran

http://…/publisher1 O’Reilly

title

name

author

publisher

isbn

http://…/

isbn978

owl:sameAs

http://…/

review1

Awesome Book

http://…/

reviewer

Juan Sequeda


hasReview

hasReviewer

description

name

owl:sameAs

livesIn

Juan Sequedaname


SELECT ?review ?commentWHERE {isbn:978 ex:hasReview ?review .?review ex:description ?comment .?review ex:hasReviewer ?person .?person ex:lives dbpedia:Austin .}


www.capsenta.com 57

This looks cool, but let’s be realistic. What is the incentive to publish Linked Data on the Web?

June 4, 2012

www.capsenta.com 58

What was your incentive to publish an HTML page in 1990?

June 4, 2012

1) Share data in documents

2) Because you neighbor was doing it

… later on …

3) Marketing, Advertising, …, SEO


www.capsenta.com 60

So why should we publish Linked Data in 2012?

June 4, 2012

1) Share data as data

2) Because you neighbor is doing it

… later on …

3) Marketing, Advertising, …, SEO


Linked Data Publishers

US and UK Government

BBC

NY Times

Best Buy

Sears

Kmart

Overstock

… too many more to nameJune 4, 2012 www.capsenta.com 62

www.capsenta.com 63

Linked Open Data

June 4, 2012

www.capsenta.com June 4, 2012

http://www.w3.org/DesignIssues/LinkedData.html

64

May 2007


Oct 2007


Nov 2007


Feb 2008


Mar 2008


Sept 2008


Mar 2009 (1)


Mar 2009 (2)


July 2009


September 2010


September 2011

Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch. http://lod-cloud.net/


YOU GET THE PICTURE

ITS BIG and getting

BIGGER and

BIGGERJune 4, 2012 www.capsenta.com 76

www.capsenta.com 77

Part 2: Linked Data Principles

June 4, 2012


Linked Data is a set of best practices to publish and interlink data on the

web

Linked Data Principles

1. Use URIs as names for things

2. Use HTTP URIs so that people can look up (dereference) those names.

3. When someone looks up a URI, provide useful information.

4. Include links to other URIs so that they can discover more things.



1. Use URIs as names for things

1) Use URIs as names for things

http://juansequeda.com/foaf.rdf#me http://www.w3.org/People/Berners-Lee/card#i

http://xmlns.com/foaf/0.1/knows

http://dbpedia.org/resource/Austin,_Texas

http://xmlns.com/foaf/0.1/based_near



2. Use HTTP URIs so that people can look up (dereference) those

names.

2) Use HTTP URIsHTTP client can lookup the URI using HTTP

protocol and retrieve a description






What’s with the redirection (303) ?


http://upload.wikimedia.org/wikipedia/commons/0/06/AustinSkylineLouNeffPoint-2010-03-29-b.JPG

June 4, 2012 www.capsenta.com 90http://dbpedia.org/page/Austin,_Texas



http://dbpedia.org/page/Austin,_Texas http://dbpedia.org/data/Austin,_Texas.xml

Accept: text/html Accept: application/rdf+xml

Identifies the abstract concept of“the city of Austin, Texas”

Identifies an HTML document that describes “the city of Austin, Texas”

Identifies an RDF document that describes “the city of Austin, Texas”















Minting HTTP URIs

If you own the domain name and run a web server at that location, mint URIs in this namespace

I own the domain capsenta.com

I run the webserver http://capsenta.com

I can mint URIs in this namespacehttp://capsenta.com/person/Juan-Sequeda


http://capsenta.com/

http://capsenta.com/person/Juan-Sequeda

Cool URIs

Don’t misuse a namespace that you don’t ownhttp://www.imdb.com/title

Avoid implementation detailshttp://capsenta.com/person.php?id=123&format=rd

f

Use Natural Keyshttp://capsenta.com/person/123


http://www.w3.org/TR/cooluris/

http://www.imdb.com/title

http://capsenta.com/person.php?id=123&format=rdf

http://capsenta.com/person.php?id=123&format=rdf

http://capsenta.com/person/123


3. When someone looks up a URI, provide useful

information.

3) Provide useful information

How do we provide useful information in document form on the web? HTML

How do we provide useful information in data form on the web RDF


What to publish?

Literal Triples

<http://dbpedia.org/resource/Austin,_Texas><http://xmlns.com/foaf/0.1/name>

“City of Austin”

Outgoing Link Triples

<http://dbpedia.org/resource/Austin,_Texas><http://www.w3.org/2002/07/owl#sameAs>

<http://rdf.freebase.com/ns/m/0vzm>

Incoming Link Triples

<http://dbpedia.org/resource/Dakota_Johnson><http://dbpedia.org/ontology/birthPlace>

<http://dbpedia.org/resource/Austin,_Texas>


What to publish?

Description of the data setSemantic SitemapsvoiD (Vocabulary of Interlinked Datasets)

Provenance Metadata

Licenses Information


Vocabularies (or Schemas or Ontologies)Create your own using

RDFS/OWL/ SKOS

Reuse vocabulariesDublin Core: metadata attributesFriend of a Friend (FOAF): persons and relationshipsSemantically Interlinked Online Communities (SIOC): describing

users, posts, blogs, etcDescription of a Project (DOAP)Music OntologyProgrammes Ontology: TV and radio programsGood Relations: describing products and servicesReview VocabularyBasic Geo (WGS84) Vocabulary



4. Include links to other URIs so that they can discover more things.

4) Include links to other things

Set external RDF links into other data sources on the WebSubject of the triple is in the namespace of one

data setObject of the triple is a URI in the namespace of

another data set

Connect siloed data islands

Enable discovery


4) Include links to other things

Relationship Link Triples

<http://juansequeda.com/foaf.rdf#me><http://xmlns.com/foaf/0.1/based_near>

<http://dbpedia.org/resource/Austin,_Texas>

Identity Link Triples

<http://dbpedia.org/resource/Austin,_Texas><http://www.w3.org/2002/07/owl#sameAs>

<http://rdf.freebase.com/ns/m/0vzm>

Vocabulary Link Triples

<http://capsenta.com/vocab/name><http://www.w3.org/2002/07/owl#equivalentProperty>

<http://xmlns.com/foaf/0.1/name>


Which predicate for linking to choose?

Depends on your domain

Is it widely used?owl:sameAsfoaf:knowsfoaf:based_near…

If you create your own, relate it to a widely used predicate


www.capsenta.com 103

Part 3: Linked Data

Architectures

June 4, 2012

Static RDF Files

Small amount of data (personal FOAF file)

Use RDF/XML serialization

Save as .rdf file and upload it to your serverhttp://www.capsenta.com/company.rdfhttp://www.capsenta.com/company.rdf#this

Configure MIME typesAddType application/rdf+xml .rdf

Make RDF discoverable from HTMl <link rel="alternate" type="application/rdf+xml" href="company.rdf">


http://www.capsenta.com/company.rdf

http://www.capsenta.com/company.rdf%23this

http://www.capsenta.com/company.rdf%23this

RDF in HTML (RDFa)

Another syntax for RDF

Useful if you have template HTML pages

Drupal 7 will do this out of the box


Triplestores (aka RDF db, …)

CommercialOracle, IBM, OntoText (OWLIM), Franz

(Allegrograph), Openlink (Virtuoso), C&P (Stardog), Ontoprise (OntoBroker), Meronymy

Open SourceJena, Sesame, Mulgara, 4Store (Garlik), BigData

(Systap)


RDB2RDF

Upcoming W3C RDB2RDF StandardsR2RML: mapping languageDirect Mapping: default automatic mapping

Two ApproachesDynamic (SPARQL to SQL)ETL (Dump RDB to RDF)

UltrawrapSupports W3C standard and moreSPARQL as fast as SQL


www.capsenta.com

Unstructured to RDF

June 4, 2012

Unstructured

Entity Extractor

Triplestore

108

www.capsenta.com

Semi-structured to RDF

June 4, 2012

Semi-structured

XML2RDF, XLS2RDF, CVS2RDF

Triplestore

109

www.capsenta.com

RDB to RDF

June 4, 2012

RDB2RDF ETL

Triplestore

Relational Database

RDB2RDF (SPARQL to

SQL)

CMS with RDFa, Semantic Wiki

110

Creating Linked Data


StructuredSemi-structured

Unstructured

Entity Extractor

XML2RDF, XLS2RDF, CVS2RDF

RDB Data source with API

Triplestore

Web Server Linked Data

InterfaceRDB2RDF

(i.e. Ultrawrap)CMS with RDFa, Semantic Wiki

Custom Linked Data Wrapper

Linked Data

Type of Data

Data Preparation

Data Storage

Data Publication

Thanks Heath and Bizer

RDB2RDF

Consuming Linked Data



Linked Data

Schema Mapping Record Linkage

Data Access

Application

Provenance Tracking

Schema Matching

Renaming<ex:name> <foaf:name>owl:equivalentClass and owl:equivalentPropertyrdfs:subClass or rdfs:subProperty

Structural Transformation<ex:Juan> <ex:lives> “Austin”<ex:Juan><foaf:based_near><db:Austin> .

<db:Austin><rdfs:label> “Austin”.

SPARQL Construct, RIF, R2R


Record Linkage

Different URIs that identify the same thing

Create owl:sameAs links between them

Manually lookup: Sindice

(Semi) Automatically: SILK


Provenance

Keep track where the data is coming fromQualityTrust

Named Graphs

SPARQL Graph


www.capsenta.com

Centralized

June 4, 2012


Triplestore

Application

SPARQL

116

Centralized

AdvantageInclude the datasets that you needComplex queries and high performanceReasoning

DrawbacksDepends on RDF dumps or crawlingEffort to setup the centralized triplestoreQueried data may be out of date


Federated


TriplestoreRelational Database

RDB2RDF

Relational Database

RDB2RDF

Triplestore

Federator

Application

SPARQL

SPARQL SPARQLSPARQL SPARQL

Federated

AdvantageInclude the datasets that you needQueried data is up to date

DrawbacksRequires existence of a SPARQL endpointEffort to setup federator


Linked Traversal


Linked Data

Relational Database

RDB2RDF

Triplestore

Application

SPARQL

Linked Traversal Query Engine

Linked Traversal

AdvantageNo need to know the data sources in advanceDoes not depend on the existence of SPARQL

endpoints or RDF dumpsQueried data is up to date

DrawbacksQuery execution time is slowUnsuitable for some queriesResults may be incompleteStill in research


Applications

Linked Data Browsershttp://browse.semanticweb.org/

Linked Data (Semantic Web) Search EnginesFalcons, SWSE, VisiNav, Sindice, Sigma, Swoogle,

Watson

Search EnginesGoogle, Bing, Yahoo!

Faceted Browsershttp://dbpedia.neofonie.de/browse/


http://browse.semanticweb.org/

http://browse.semanticweb.org/

Domain Specific Applications

BBC World Cup

Seevl.net

Linked Life Data

Government apps



Part 2: Linked Enterprise

Data

June 4, 2012

www.capsenta.com June 4, 2012

Consume Linked (Open) Data

PublishLinked (Open) Data

UseLinked Data Principles

internally

125

Linked Enterprise Data

Linked Data can be used as an architectural style for integrating data in the Enterprise

1. Standard Data Access Mechanism: HTTP

2. Standard Address & Identifier Scheme: URI

3. Standard Data Model: RDF


www.capsenta.com

Linked Enterprise Data

Information creation information sharing

Produce and consume data specific to your needs but also produce it in a way that it can be connected to other data in the enterprise

Distributed but connected!

Data that you create, may benefit others! Share it!

June 4, 2012 127

Benefits of RDF/Linked Data

RDF (graphs) is a least common denominatorText, CVS, XML, XLS, RDB to RDFImagine modeling a social network in XML

Dynamic and FlexibleAdding a column to a table in my RDBMS takes 6

months to authorize!With RDF, simply add the triple!Incremental


Benefits of RDF/Linked Data

Power of the URI and LinksUniversal IdentifierCreate a “foreign key” to a table that I have no

control of

Scalability in months, not only seconds“More can be done with less and faster”“Cooperation without coordination”


What’s next?

W3C Linked Data Platform Working Grouphttp://www.w3.org/2012/ldp/charter

Linked Data Basic Profile 1.0http://www.w3.org/Submission/ldbp/


http://www.w3.org/2012/ldp/charter

http://www.w3.org/2012/ldp/charter

http://www.w3.org/Submission/ldbp/

http://www.w3.org/Submission/ldbp/


Summary

June 4, 2012

Linked Data Checklist

Does your data link to other data sets?

Do you provide provenance metadata?

Do you provide licensing metadata?

Do you reuse common vocabularies?

Do you map proprietary vocabulary terms to common vocabularies?

Do you provide other access methods?

June 4, 2012 www.capsenta.com

Thanks Heath & Bizer

Acknowledgements

RiBS Lab – UT Austin

Olaf Hartig – Humboldt University Berlin

Patrick Sinclair – BBC

Jamie Taylor – Google

Tom Heath & Chris Bizer. Linked Data: Evolving the Web into a Global Data Space

David Wood (Ed.). Linking Enterprise Data


Thanks!

Juan F. Sequeda

[email protected]

@juansequeda


Daniel P. Miranker

[email protected]

www.capsenta.com

mailto:[email protected]

mailto:[email protected]

Linked Data tutorial at Semtech 2012

Technology

Transcript of Linked Data tutorial at Semtech 2012