Linked Datawifo5-03.informatik.uni-mannheim.de/bizer/pub/Bizer...Deutsches Kulturerbe auf dem Weg in...

Deutsches Kulturerbe auf dem Weg in die EuropeanaOctober 5th, 2010, Berlin, Germany

Linked DataLinked DataE t di th W b ith Extending the Web with a global public Dataspace

Prof. Dr. Christian Bizer Freie Universität Berlin

Christian Bizer: Europeana Conference (05/10/2010)

Outline

1. Foundations of Linked Data What is the vision and goal?

2. The Web of Linked Data What data is out there?

3. Linked Data Applications What is being done with the data?


Linked Data Principles

Set of best practices for publishingSet of best practices for publishing structured data on the Web in accordance with the general architecture of the Web.

1 Use URIs as names for things1. Use URIs as names for things.

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

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

4. Include RDF statements that link to other URIs so that they can discover related things.

Tim Berners-Lee, http://www.w3.org/DesignIssues/LinkedData.html, 2006


Architecture of the classic Web

Single global information spaceWeb

BrowsersSearch Engines

Single global information space

S ll t f i l t d dSmall set of simple standards1. HTML as document format2 HTTP URL

HTTP

HTML HTMLHTML

2. HTTP URLs as globally unique IDs retrieval mechanism

hyper-links

retrieval mechanism

3. Hyperlinks to connect everything

B CA B CA


Web 2.0 APIs and Mashups

No single global dataspaceMashup

Up

No single global dataspace

Sh t iShortcomings

1. APIs have proprietary interfaces

WebAPI

2. No hyperlinks between data items within different APIs

3 M h b d

WebAPI

WebAPI

WebAPI

3. Mashups are based on a fixed set of data sources

A B C DA B C D


Web APIs slice the Web into Walled Gardens

Christian Bizer: Europeana Conference (05/10/2010)Image: Bob Jagensdorf, http://flickr.com/photos/darwinbell/, CC-BY

Linked Data

Extend the Web with a single global dataspace1. by using RDF to publish structured data on the Web2. by setting links between data items within different

data sources.

RDF RDF RDF RDF RDFRDF

RDF

RDF

RDF

RDF

RDF RDF

RDF

RDF

RDF

RDFlink

RDFlinks

RDFlinks

RDFlinks

B CA D E


The RDF Data Model

rdf:type

f f

foaf:Personrdf:type

pd:cygri

Richard Cyganiakfoaf:name

foaf:based neardbpedia:Berlin

foaf:based_near

Flexible graph-based data model.


Data items are identified with HTTP URIs

rdf:typepd:cygri

f f

foaf:Personrdf:type

Richard Cyganiakfoaf:name

foaf:based neardbpedia:Berlin

foaf:based_near

HTTP URIs take the role of global primary keys.

d i htt // i h d i k d /f f df# ipd:cygri = http://richard.cyganiak.de/foaf.rdf#cygridbpedia:Berlin = http://dbpedia.org/resource/Berlin


Resolving URIs over the Web

rdf:type

3 405 259f f

foaf:Personrdf:type

pd:cygri

3.405.259dp:populationRichard Cyganiak

foaf:name

foaf:based near

skos:subject

dbpedia:Berlinfoaf:based_near

d Citi i G

skos:subject

dp:Cities_in_Germany

The HTTP protocol brings together identification and retrie al


retrieval.

Following RDF links deeper into the Web

rdf:type

3 405 259f f

foaf:Personrdf:type

pd:cygri

3.405.259dp:populationRichard Cyganiak

foaf:name

foaf:based near

skos:subject

dbpedia:Berlinfoaf:based_near

d Citi i G

skos:subject

db di H bskos:subject

dp:Cities_in_Germanydbpedia:Hamburg

dbpedia:Muenchen skos:subject


The Disco – Hyperdata Browser


Properties of the Web of Linked Data

Global, distributed dataspace build on a simple set of standards RDF, URIs, HTTP

Entities are connected by links creating a single global data graph that spans data sources and

enables the discovery of new data sources

Provides for data-coexistence Everyone can publish data to the Web of Linked Data Everyone can publish data to the Web of Linked Data

Everyone can express their personal view on things

Everybody can use the vocabularies/schema that they like Everybody can use the vocabularies/schema that they like


2. Linked Data Deployment on the Web

Is this real?

RDF RDF RDF RDF RDFRDF

RDF

RDF

RDF

RDF

RDF RDF

RDF

RDF

RDF

RDFlink

RDFlinks

RDFlinks

RDFlinks

B CA D E


W3C Linking Open Data Project

Grassroots community effort toy publish existing open license datasets as Linked Data on the Web interlink things between different data sources


LOD Datasets on the Web: May 2007

Over 500 million RDF triples


p Around 120,000 RDF links between data sources

LOD Datasets on the Web: September 2008


LOD Datasets on the Web: July 2009


Over 13.1 billion RDF triples Over 142 million RDF links between data sources

LOD Datasets on the Web: September 2010


Over 25 billion RDF triples Over 395 million RDF links between data sources

Uptake in Life Sciences

W3C Linking Open Drug Data Effort

Bio2RDF Project

Allen Brain Atlas

Goal: Use single architecture to integrate internal and external data


and external data.

Uptake in the Media Industry

Publish data as RDF/XML or RDFa

Goal: Drive traffic to websites via Goal: Drive traffic to websites via search engines, other sites


Uptake in the Libraries Community

Institutions publishing Linked Data Library of Congress (subject headings)

Deutsche Nationalbibliothek (PND dataset and subject headings)

Deutschen Zentralbibliothek für Wirtschaftswissenschaften (subject headings)

Swedisch National Library (Libris - catalog)

Hungarian National Library (OPAC and Digital Library)

W3C Library Linked Data Incubator Group

Open Archives ORE StandardOpen Archives ORE Standard

Goals:Goals: Integrate library catalogs on global scale.

Interlink content between repositories (locations people citations )


Interlink content between repositories (locations, people, citations, …)

3. Linked Data Applications

What can I do with this?

Search Engines

Linked DataMashups

Linked DataBrowsers EnginesMashupsBrowsers

Thing Thing Thing Thing ThingThing

Thing

Thing

Thing

Thing

Thing Thing

Thing

Thing

Thing

typedlinks

typedlinks

typedlinks

typedlinks

B CA D E


Linked Data Browsers

P id f i ti b t d tProvide for navigating between data sources and for exploring the dataspace.

Tabulator Browser (MIT, USA)

Marbles (FU Berlin, DE)

OpenLink RDF Browser (OpenLink, UK)p ( p )

Zitgist RDF Browser (Zitgist, USA)

Di H d t B (FU B li DE)Disco Hyperdata Browser (FU Berlin, DE)

Fenfire (DERI, Irland)


Web of Data Search Engines

C l th d t d id b t ff tCrawl the dataspace and provide best-effort query answers over crawled data.

VisiNav (DERI, Ireland)

Falcons (IWS, China)

Sig.ma (DERI, Ireland)

Swoogle (UMBC, USA)

W t (O U i it UK)Watson (Open University, UK)


What are the big players doing?


Yahoo!

crawls Linked Data in its RDFa serialization as well as Microformats.

provides access to crawled data through the Yahoo BOSS API provides access to crawled data through the Yahoo BOSS API

is using the data within Yahoo Search Monkey to make search results more useful and visually appealing.more useful and visually appealing.


Google

uses crawled data to enhance search results snippets and to feed its Social Graph APIand to feed its Social Graph API

is developing Google Squared and Google Fusion Tables

has recently bought MetaWeb which maintains Freebase, a DBpedia/YAGO competitor, p p

is starting to use structured data in its applications


Conclusion

Linked Data provides best practices for publishing structured data on the Webstructured data on the Web Simple set of standards: RDF, URIs, HTTP

E bl t d di d f id f t l Enables standardized access for wide range of tools:browsers, crawlers, mashups

Th W b f Li k d D t i i idl The Web of Linked Data is growing rapidly Active deployment communities exist in various domains

H d d th iti l Has exceeded the critical mass

Web search is evolving into query answering Search engines will increasingly rely on structured data from the Web

We are getting closer to being able to use the Web like aWe are getting closer to being able to use the Web like a global distributed database.


Thanks!

References Christian Bizer, Tom Heath, Tim Berners-Lee: Linked Data – The Story So Far

h // h h / /bi h h b l ij i li k d d dfhttp://tomheath.com/papers/bizer-heath-berners-lee-ijswis-linked-data.pdf

Linking Open Data Project Wiki http://esw w3 org/topic/SweoIG/TaskForces/CommunityProjects/LinkingOpenDatahttp://esw.w3.org/topic/SweoIG/TaskForces/CommunityProjects/LinkingOpenData

3rd Linked Data on the Web Workshop at WWW2010http://events.linkeddata.org/ldow2010/


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