global public Dataspace

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1 Deutsches Kulturerbe auf dem Weg in die Europeana October 5 th, 2010, Berlin, Germany Linked Data Extending the Web with a global public Dataspace Prof. Dr. Christian Bizer Freie Universität Berlin

2 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?

3 Linked Data Principles Set 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 things. 2. Use HTTP URIs so that people can look up those names. 3. When someone looks up a URI, provide useful information. 4. Include statements that link to other URIs so that they can discover related things. Tim Berners-Lee,

4 Architecture of the classic Web Web Browsers Search Engines Single global information space Small set of simple standards d HTTP 1. HTML as document format 2. HTTP URLs as HTML hyperlinks HTML HTML globally unique IDs retrieval mechanism 3. Hyperlinks to connect everything A B C

5 Web 2.0 APIs and Mashups Mashup Up No single global dataspace Shortcomings 1. APIs have proprietary interfaces Web API Web API Web API Web API 2. No hyperlinks between data items within different APIs 3. Mashups are based on a fixed set of data sources A B C D

6 Web APIs slice the Web into Walled Gardens Image: Bob Jagensdorf, CC-BY

7 Linked Data Extend the Web with a single global dataspace 1. by using to publish structured data on the Web 2. by setting links between data items within different data sources. link links links links A B C D E

8 The Data Model pd:cygri rdf:type foaf:person foaf:namef Richard Cyganiak foaf:based_near dbpedia:berlin Flexible graph-based data model.

9 Data items are identified with HTTP URIs pd:cygri rdf:type foaf:person foaf:namef Richard Cyganiak foaf:based_near dbpedia:berlin HTTP URIs take the role of global primary keys. pd:cygri = h i d /f f df# i dbpedia:berlin =

10 Resolving URIs over the Web pd:cygri rdf:type foaf:person foaf:namef Richard Cyganiak foaf:based_near dbpedia:berlin dp:population skos:subject dp:cities_in_germany i The HTTP protocol brings together identification and retrieval.

11 Following links deeper into the Web pd:cygri rdf:type foaf:person foaf:namef Richard Cyganiak foaf:based_near dbpedia:berlin dp:population dbpedia:hamburgdi b skos:subject skos:subject dp:cities_in_germany i dbpedia:muenchen skos:subject

12 The Disco Hyperdata Browser

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14 Properties of the Web of Linked Data Global, distributed dataspace build on a simple set of standards, 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 express their personal view on things Everybody can use the vocabularies/schema that they like

15 2. Linked Data Deployment on the Web Is this real? link links links links A B C D E

16 W3C Linking Open Data Project Grassroots community effort to publish existing open license datasets as Linked Data on the Web interlink things between different data sources

17 LOD Datasets on the Web: May 2007 Over 500 million triples Around 120,000 links between data sources

18 LOD Datasets on the Web: September 2008

19 LOD Datasets on the Web: July 2009 Over 13.1 billion triples Over 142 million links between data sources

20 LOD Datasets on the Web: September 2010 Over 25 billion triples Over 395 million links between data sources

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23 Uptake in Life Sciences W3C Linking Open Drug Data Effort Bio2 Project Allen Brain Atlas Goal: Use single architecture to integrate internal and external data.

24 Uptake in the Media Industry Publish data as /XML or a Goal: Drive traffic to websites via search engines, other sites

25 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 Standard Goals: Integrate library catalogs on global scale. Interlink content between repositories (locations, people, citations, )

26 3. Linked Data Applications What can I do with this? Linked Data Browsers Linked Data Mashups Search Engines Thing Thing Thing Thing Thing Thing Thing Thing Thing Thing typed links typed links typed links typed links A B C D E

27 Linked Data Browsers Provide for navigating between data sources and for exploring the dataspace. Tabulator Browser (MIT, USA) Marbles (FU Berlin, DE) OpenLink p Browser (OpenLink, UK) Zitgist Browser (Zitgist, USA) Disco Hyperdata Browser (FU Berlin, DE) Fenfire (DERI, Irland)

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29 Web of Data Search Engines Crawl the dataspace and provide best-effort t query answers over crawled data. VisiNav (DERI, Ireland) Falcons (IWS, China) Sig.ma (DERI, Ireland) Swoogle (UMBC, USA) Watson (Open University, it UK)

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32 What are the big players doing?

33 Yahoo! crawls Linked Data in its a serialization as well as Microformats. 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.

34 Google uses crawled data to enhance search results snippets and 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 is starting to use structured data in its applications

35 Conclusion Linked Data provides best practices for publishing structured data on the Web Simple set of standards:, URIs, HTTP Enables standardized di d access for wide range of tools: browsers, crawlers, mashups The Web of Linked Data is growing rapidly Active deployment communities exist in various domains Has exceeded d 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 a global distributed database.

36 Thanks! References Christian Bizer, Tom Heath, Tim Berners-Lee: Linked Data The Story So Far h h / /bi h hb ij i li d df Linking Open Data Project Wiki 3 rd Linked Data on the Web Workshop at WWW2010