Linked Open Data projects aim to extend the web of documents to a web of linked data by adding semantics through standards like RDF and ontologies. The Linked Open Data cloud has grown significantly since 2007 and contains billions of RDF triples and links between data sources. Projects like LOD2 build on this by developing technologies and linking more open datasets to enable new applications. For Linked Data to achieve its full potential, openness and allowing free access and reuse is important, though it does mean losing some control over data usage.

1. Linked Open Data: Principles & 2 Projects Prof. Dr. Stefan Gradmann Humboldt-Universität zu Berlin / School of Library and Information Science [email_address]

3. LoD & LOD2: two projects

4. Conclusion : on the importance of being 'open'

7. In scope (including re- presentations of non- information resources, 'things', 'data')

10. hierarchies of classes and properties,

11. inheritance

13. Extending the Web in Scope: the way it does not work! Taken from Ronald Carpentier's Blog at http://carpentier.wordpress.com/ 2007/08/08/1-2-3/ Something is wrong with this picture (but what?)

14. … and the way extending the Web in scope is actually done: A Web of Things

15. … Linked Data Copyright © 2008 W3C (MIT, ERCIM, Keio) http://www.w3.org/2008/Talks/0617-lod-tbl/#(4) Standard Identifiers Standard Pointers Standards for Queries and Statements Link to Context

16. A few Bubbles: 5/2007 < Over 500 million RDF triples < Around 120,000 RDF links between data sources © Richard Cyganiak

17. Quite some Bubbles: 9/2008 © Richard Cyganiak

18. Many Bubbles: 7/2009 © Richard Cyganiak < Over 13.1 billion RDF triples < Over 142 million RDF links between data sources

19. (Too?) Many Bubbles: 9/2010 http://richard.cyganiak.de/2007/10/lod/lod-datasets_2010-09-22_colored.html

21. PND and SWD (prototype)

22. Geonames

23. LCSH

24. …

26. “ The goal [...] is to build a data commons by making various open data sources available on the Web as RDF and by setting RDF links between data items from different data sources.”

27. First gathering in Banff at WWW2007 with pioneers such as Tom Heath , Chris Bizer , Kingsley Idehen, Yrjana Rankka, Orri Erling, Ivan Mikhailov, Danny Ayers, Steve Coast, Peter Murray Rust, Alan Ruttemberg, Ian Horrocks, Bernardo Cuenca Grau, Boris Motik, Danny Gagne.

28. Current discussion: how to switch from mere volume to quality ? Matching, mapping and referrals are central

29. Tom Heath and Christian Bizer (2011) Linked Data: Evolving the Web into a Global Data Space (1st edition). Morgan & Claypool. http://linkeddatabook.com/editions/1.0/

32. D2R Server (Relational to RDF)

33. DBPedia Extraction from Wikipedia

34. OntoWiki (agile, distributed knowledge engineering)

35. Silk Link Discovery Framework

40. But it gets quite expensive that way …

41. … much too expensive, probably, for Europeana to afford!

42. Or else (LD behind a proxy) it is straightaway parasitic.

45. No income to be generated from data access and use

48. -> What is the actual value of context (in business terms!)?

49. Thank you for your attention!