methodological guidelines for publishing linked data

Methodological Guidelines for Publishing Linked Data

Boris Villazón-Terrazas, Asunción Gómez-Pérez, and Óscar Corcho

Facultad de Informática, Universidad Politécnica de MadridCampus de Montegancedo sn, 28660 Boadilla del Monte, Madrid

http://www oeg upm nethttp://www.oeg-upm.net{bvillazon,asun,ocorcho}@fi.upm.es

Phone: 34.91.3366605, Fax: 34.91.3524819

Cochabamba, BoliviaMay, 2011

ToC

• Ontology Engineering Group

• Introduction to Linked Data

• Guidelines for Publishing Linked Data

• Demo

2

ToC




• Demo

3

People

• Director: A. Gómez-Pérez• Research Group (38 people)

• 2 Full Professors• 6 Associate Professors• 1 Assistant Professor• 6 Postdocs• 14 PhD Students• 6 MSc Students• 4 Software Engineers

• Management (5)• 3 Project Managers• 3 Project Managers• 1 System Administrator• 1 Secretary

• 80+ Past Collaborators• 80+ Past Collaborators• 15+ visitors

4

http://www.oeg-upm.net

Students from...

France

G

Lithuania

Italy

France

Serbia

Macedonia

Germany

MalaysiaColombia

India

EcuadorCameroon

Bolivia

Ecuador

5

> 30 Research projects1999 20022000 2001 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 20131999 20022000 2001 2003 2004 2005 2006 2007

Katalyx

Group

IGN/RAE/AMPER/XMEDIA2008 2009 2010

E ñ Vi t l/ IO!/B diPLATA

WHO/IGN/BNE/FAO2011 2012 2013

ContentWeb

20 Ac Especiales/Complementarias

Servicios Semánticos

REIMDOC (FIT) Red/Gis4Gov/11811/UPnP/UpGrid/Autores3.0/WEBn+1

GeoBuddies

España Virtual/mIO!/BuscamediaPLATA

BabelData / myBigData

HA98-0002

MKBEEMO t W b

HF02-0013

20 Ac. Especiales/Complementarias

SEEMPNeOnOntoWeb

Esperonto

PIKONKnowledge Web

NeO

ADMIRE

DynaLearn

OntoGrid

Marie Curie

SemSorGrid4Env

SEALS

MONNET

Company EU Project Coordinators

SCALUS

PlanetData

Wf4Ever

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Company EU Project CoordinatorsSpanish Projects EU Project Participation

Collaboration with international companies

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Collaboration with other research groups

Univ. of Amsterdam

i f d

DFKI

Univ. of Augsburg

Univ. of Karlsruhe

U i f K bl

KSL. Stanford Univ.

Univ. of Wien

Univ. of NR & ALS

Univ. of InnsbruckFree Univ. of Amsterdam Univ. of Koblenz

Univ. of Hannover

Univ. of Mannheim

Univ of Bielefeld

Univ. of Brasilia

Univ. of Bielefeld

Forschungszentrum Informatik

Univ. of Galway (DERI)

Free Univ. of Brussels

Úniv. of Zurich

Open University

O f d U i it

Ústav Informatiky

Oxford University

Univ. of Manchester

Univ. of Liverpool

Univ of Sheffield

Academy of Sciences

Univ. of Sheffield

Univ. of Aberdeen

Univ. of Edinburgh

Univ. of Southampton

CNR

Univ of Trento

Univ. of Tel Aviv

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Univ. of Southampton

Univ. of Hull

Univ. of Trento

Univ. of BolzanoINRIA

Univ. of Athens

TUC

Research Areas

2004 2008

Internet of Things

Semantic e-Science(Data Integration, Semantic Grid)

Ontological Engineering1995Semantic Grid) 1995

(S i l) N l(Social) Semantic

Web

Natural LanguageProcessingg

19972000

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Linked Data in OEG

• GeoLinkedData is an open initiative whose aim is toenrich the Web of Data with Spanish geospatial data.p g phttp://geo.linkeddata.es

• El Viajero Linked Data is project that focuses on theintegration of the contents produced by newspapersand digital platforms belonging to Prisa Groupand digital platforms belonging to Prisa Group.http://webenemasuno.linkeddata.es/

• A project with the Biblioteca Nacional to publish thelibrary information as Linked Data.yhttp://cultura.linkeddata.es/visualizer/

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Linked Data in OEG

• Tools for generating and cosuming Linked Data, e.g.,• geometry2rdf http://www oeg upm net/index php/downloads/151 geometry2rdf• geometry2rdf http://www.oeg-upm.net/index.php/downloads/151-geometry2rdf

• map4rdf http://oegdev.dia.fi.upm.es/projects/map4rdf/

• Spanish Thematic Network of Linked Data http://red.linkeddata.esp

» Group leader: Ontology Engineering Group

» 19 Research Groups

» 4 companies» 4 companies

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ToC




• Demo

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Classic Web

MovieDB

Data exposed tothe Web viathe Web via

HTML, pdf, etc.

CIAWorld

FactBook

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© Slide adapted from “5min Introduction to Linked Data”- Olaf Hartig

Classic Web

Information fromsingle pagesComplex queries

l i ls g e pages

can be found viasearch engines

over multiplepages / data

?sea c e g es

sources?

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What do we actually want?

• Use the Web like a single global database

MovieDBCIA

WorldFactBook

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Linked Data enables such Web of DataGlobal Identifier: URI (Uniform Resource Identifier) which is a string of characters usedGlobal Identifier: URI (Uniform Resource Identifier), which is a string of characters used

to identify a name or a resource on the Internet.Data Model: RDF (Resource Description Framework), which is a standard model

for data interchange on the WebAccess Mechanism: HTTPConnection: Typed Links

8000000

“Even the Rain”

http://cia.../Boliviahttp://imdb.../TLLuvia

http://.../populationhttp://.../name

http://.../filming_location

p

MovieDBCIA

WorldFactBook

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In a nutshell• An extension of the current• An extension of the current

Web…• … where information and services data

are given well-defined and explicitly represented meaning, …

• … so that it can be shared and used by humans and machinesby humans and machines, ...

• ... better enabling them to work in cooperation

• How?• Promoting information exchange by

tagging web content with machine processable descriptions of its meaning. A d t h l i d i f t t• And technologies and infrastructureto do this

• And clear principles on how to publish data

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publish data

The four principles (Tim Berners Lee, 2006)

1. Use URIs as names for things

• http://www.w3.org/DesignIssues/Linkedfor things

2. Use HTTP URIs so that people can look

esignIssues/LinkedData.html

that people can look up those names.

3. When someone looks http://www.ted.com/talks/tim_berners_lee_on_the_next_web.htmlhttp://www.ted.com/talks/tim_berners_lee_on_the_next_web.html

up a URI, provide useful information,

i th t d dusing the standards (RDF*, SPARQL)

4 Include links to other4. Include links to other URIs, so that they can discover more things.discover more things.

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RDF – Resource Description FrameworkW3C d ti• W3C recommendation

RDF is a basic KR language based on semantic networks• RDF is a basic KR language based on semantic networks

• Useful to represent metadata and describe any type of• Useful to represent metadata and describe any type of information in a machine-accesible way (aka data model)

• Resources are described in terms of properties and property values using RDF statementSt t t t d t i l i ti f• Statements are represented as triples, consisting of a subject, predicate, and object [S,P,O]

Subject Objectproperty

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Statement

© Slide adapted from “RDF and RDF Schema”- Raúl García et al.

RDF - Example“Alex Villazón”Alex Villazón

hasName

hasColleaguehttp://upb.edu/Alex http://upb.edu/Hugo

htt // b d /B t

hasColleague

“M l ”http://upb.edu/Beto “Male”

• For practical purposes, specially if handwritten, URIs are shortened using XML namespaces• xmlns:upb=“http://upb edu/”

hasSex

xmlns:upb http://upb.edu/• upb:Alex is equivalent to http://upb.edu/Alex• RDF serializations: XML, N3, N-Triple

“Alex Villazón”

person:hasName

upb:Alex upb:Hugoperson:hasColleague

person:hasColleague

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upb:Beto “Male”person:hasSex

© Slide adapted from “RDF and RDF Schema”- Raúl García et al.

RDF - SPARQL“Alex Villazón”

person:hasName

person hasColleag eupb:Alex upb:Hugo

person:hasColleague

person:hasColleague

• Query: “Tell me who are the persons who have Hugo as colleague”

upb:Beto “Male”person:hasSex

upb:Hugo?person:hasColleague

• Result: upb:Alex and upb:Beto

SPARQL l f RDF W3C d i• SPARQL query language for RDF. W3C recommendationSELECT ?s WHERE { ?s person:hasColleague upb:Hugo.}

21© Slide adapted from “RDF and RDF Schema”- Raúl García et al.

So does that mean I have to publish my data as Linked Data, now?

• But, why?

• What was your incentive to publish an HTML page in 1990?• Share data in documents and because your neighbor

was doing itwas doing it

• So, why should we publish Linked Data in 2011?, y p• Share data as data and because your neighbor is doing it

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© Slide adapted from “Introduction to Linked Data”- Juan Sequeda

And guess who is starting to publish Linked Data now?

• UK Government• UK Government• US Government• BBC• Open Calais• Freebase• NY Times• CNET• Dbpedia• Dbpedia• ….

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Linked Open Data evolution

2007

2008

2009

2424

Linked Open Data

2010

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http://richard.cyganiak.de/2007/10/lod/

ToC




• Demo

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Guidelines for Publishing Linked Data

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Identification of the data sources

• Guidelines based on the Open Data Manual 1

• Two possibilities

• To find the data sources already available in a public data catalog, e.g., Aporta project 2

• To get an agreement with a particular government body topublish its data sources, e.g., GeoLinkedData - IGNp g

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1 http://opendatamanual.org/2 http://aporta.es

GeoLinkedDataIdentification of the data sources

IGNNational Geographic Institute of Spain

Agreement with the IGN

g p p

Oracle & MySQL

Data sources availablein a public data catalog

INENational Statistic Institute of Spain

in a public data catalog

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IGN & INEIdentification of the data sources

Year

Industry Production IndexProvince

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OntologyVocabulary Modelling

• An ontology is an engineering artifact, which provides: • A set of terms• A set of explicit assumptions regarding the intended meaning of the terms.

• Almost always including concepts and their classification• Almost always including properties between concepts

Shared nderstanding of a domain of interest• Shared understanding of a domain of interest

• Ontologies expressed in OWL or RDF(S), both based on RDFOntologies expressed in OWL or RDF(S), both based on RDF

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Reuse available vocabulariesVocabulary Modelling

Search for suitablevocabularies

Linked Open Vocabularies

are theresuitable

vocabularies?

Build the vocabulary byreusing available

vocabularies

Yes

No

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…

Reuse available non-ontological resourcesVocabulary Modelling

Highly reliable Web Sites

Search for suitablenon-ontological resources

Domain-related sites

Government CatalogsGovernment Catalogs

are theresuitable

resources?

Build the vocabulary bytransforming available

resources

Yes

No

Build the vocabulary fromscratch

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GeoLinkedDataVocabulary Modelling

scv:Dimensionscv:Item

scv:Dataset

WGS84 Geo Positioning: an RDF

vocabulary

hydrographical phenomena (riversphenomena (rivers,

lakes, etc.)

Vocabulary for instants, intervals, , ,durations, etc.

Ontology for OGC Geography Markup Language

Names and international code systems for territories and groupsg g

Classes 33 33

Object Properties 44 44

http://neon-toolkit.org/

j p

Data Properties 318 318

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Generation of the RDF Data

INEINE

NOR2O

ODEMapster

IGNIGN

IGNIGN

GeospatialGeospatialcolumncolumn

Geometry2RDF

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NOR2OIndustry Production Index Year


Industry Production Index

ProvinceProvince

NOR2O

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R2O & ODEMapsterR O is an extensible fully declarative language to describe


• R2O is an extensible, fully declarative language to describe mappings between relational database schemas and ontologies.

• The ODEMapster processor generates RDF instances from relational instances based on the mapping description expressed in the R2O document

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www.oeg-upm.net/index.php/en/downloads/9-r2o-odempaster

R2O & ODEMapsterGeneration of the RDF Data

• Creation of the R2O Mappings

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R2O & ODEMapsterGeneration of the RDF Data

Excerpt of the R2O documentExcerpt of the R2O document

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geometry2rdfGeneration of the RDF Data

• Tool for generating RDF from geometrical information

• The geometry could be available in GML or WKT

• The RDF generated follows our Geometry Model

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http://www.oeg-upm.net/index.php/en/downloads/151-geometry2rdf


Oracle STO UTIL packageOracle STO UTIL package

SELECT TO_CHAR(SDO_UTIL.TO_GML311GEOMETRY(geometry)) AS Gml311Geometry

FROM "BCN200"."BCN200_0301L_RIO" cWHERE c.Etiqueta='Arroyo'

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Geometry ModelGeneration of the RDF Data

geoes: http://geo.linkeddata.es/geo: http://www.w3.org/2003/01/geo/wgs84_pos#

geoes:ontology/Geometría

rdfs:subClassOf rdfs:subClassOf

geoes:ontology/Polígonogeoes:ontology/Curvageo:Point

rdfs:subClassOfrdfs:subClassOf

rdfs:subClassOf

3939geo:lat geo:long Collection of 2 or Collection of 3 or

formadoPor formadoPor

more geo:PointsCollection of 3 ormore geo:Points

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RDF generated according to our Geometry ModelGeneration of the RDF Data

1 2

0

0

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URI GenerationGeneration of the RDF Data

• URIs are extremely relevant in this process since they are the key for the alignment of heterogeneousthey are the key for the alignment of heterogeneous resources that come from different data sources.• Cool URIs 1

• UK Cabinet Office 2

• Examples:http://geo.linkeddata.es/ontology/{class/property}

http://geo.linkeddata.es/ontology/Lago

http://geo linkeddata es/resource/dataset/type/{resourcename}http://geo.linkeddata.es/resource/dataset/type/{resourcename}

http://geo.linkeddata.es/resource/Provincia/Madrid

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1 http://www.w3.org/TR/cooluris/2 http://www.cabinetoffice.gov.uk/media/301253/puiblic sector uri.pdf

Provenance InformationGeneration of the RDF Data

• It is relevant• to manage the provenance information of the resources• to manage the provenance information of the resources• to establish the license of the information

• Example

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Pubby: http://www4.wiwiss.fu-berlin.de/pubby/


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Publication of the RDF data

map4rdf

map4rdfhttp://oegdev.dia.fi.upm.es/projects/map4rdf/

SPARQLLinked DataHTML

PubbyIncluding Provenance Pubby

Pubby 0.3

Including ProvenanceSupport

http://www4.wiwiss.fu-berlin.de/pubby/

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Virtuoso 6.1.0


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Data Cleansing

• To find possible errors, identified by Hogan et al.• http-level issues such as accessibility and derefencability• http-level issues, such as accessibility and derefencability,

e.g., HTTP URIs return 40x/50x errors• reasoning issues such as namespace without vocabulary,

e.g., rss:item term invented• malformed/incompatible datatypes, e.g., “true” as xsd:int

• To fix the identified errors

• Example, encoding URIs• Special characters á é ñSpecial characters á, é, ñ

• http://geo.linkeddata.es/resource/Provincia/M%C3%A1laga

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Linking the RDF Data

Identify suitable data sets li ki t t

http://ckan.netas linking targets

Discover relationshipsbetween data items

Silk FrameworkLIMEShttp://aksw.org/Projects/limes http://www4.wiwiss.fu-berlin.de/bizer/silk/

Validate the relationshipsdiscovered sameAs Validator

http://oegdev.dia.fi.upm.es:8080/sameAs/

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GeoLinkedDataLinking the RDF Data

GeoLinkedData

GeoNamesDBPedia

…. …. ….

http://sws.geonames.org/6355233/

http://geo.linkeddata.es/.../Madrid

http://dbpedia.org/resource/Madrid

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…. …. ….

sameAs ValidatorLinking the RDF Data

http://oegdev.dia.fi.upm.es:8080/sameAs/

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Register the dataset into CKAN RegistryEnable Effective Discovery

• Add the dataset to CKAN, the open registry of data and content packagesand content packages

• Minimum information• Minimum information• Name, unique ID for your data set on CKAN• Title, full name of your data set, y• URL, link to the data set home page

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http://www.w3.org/wiki/TaskForces/CommunityProjects/LinkingOpenData/DataSets/CKANmetainformation

Sitemap protocolEnable Effective Discovery

• Used by web crawlers• Efficiently find all your content & discover

what has been updatedhttp://sitemaps.org/

A i fil i i f i di URLA sitemap file contains information regarding one or more URLs onyour Web site. The information that is stored there helps searchengines better spider your website.

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Sindice: the best RDF search engineEnable Effective Discovery

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sitemap4rdfEnable Effective Discovery

• Simple command line tool• Sends a SPARQL query to list all URIs• Generates sitemap• Generates sitemap

it 4 df htt // it / l htt // it / /sitemap4rdf http://yoursite/sparql http://yoursite/resource/

Example:

it 4 df if i th SPARQL d i t

sitemap4rdf http://geo.linkeddata.es/sparql http://geo.linkeddata.es/

• run sitemap4rdf specifying the SPARQL endpointand the prefix of the URLs to include in the Sitemap

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http://lab.linkeddata.deri.ie/2010/sitemap4rdf/

Submit the sitemap location - SindiceEnable Effective Discovery

• http://sindice.com/main/submit

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Submit the sitemap location - GoogleEnable Effective Discovery

• https://www.google.com/webmasters/tools/

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ToC




• Demo

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DEMODEMOhttp://geo linkeddata es/browserhttp://geo.linkeddata.es/browser

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Provinces

67

Capital of Province

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Provinces – Industry Production Index

69

Beaches

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DEMODEMOhttp://webenemasuno linkeddata es/http://webenemasuno.linkeddata.es/

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Trips

72

Guide Locations

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Guide

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Future Work

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Streaming resources

Methodological Guidelines for Publishing Linked Data

Boris Villazón-Terrazas, Asunción Gómez-Pérez, and Óscar Corcho

Facultad de Informática, Universidad Politécnica de MadridCampus de Montegancedo sn, 28660 Boadilla del Monte, Madrid

http://www oeg upm nethttp://www.oeg-upm.net{bvillazon,asun,ocorcho}@fi.upm.es

Phone: 34.91.3366605, Fax: 34.91.3524819

Cochabamba, BoliviaMay, 2011

methodological guidelines for publishing linked data

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