Linking Open Data


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Presentation in the context of the DPLA meeting 16th of May in Amsterdam

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  • Europeana intends to connect to the Linked Open Data community. In the Linked Open Data cloud we find many more knowledge sources like Dbpedia, Geonames, or Library of Congress Subject Headings. Europeana wants to use them to further contextualize and enrich the objects in its information space. At the same time Europeana wants to make its own data available to other communities. The EDM is crucial for realizing this vision. [ LOD cloud July 2009 ]
  • Linking Open Data

    1. 1. Linked Open Data: Principles & 2 Projects Prof. Dr. Stefan Gradmann Humboldt-Universität zu Berlin / School of Library and Information Science [email_address]
    2. 2. Overview <ul><li>Linked Data: What is it, how does it work?
    3. 3. LoD & LOD2: two projects
    4. 4. Conclusion : on the importance of being 'open' </li></ul>
    5. 5. From the Web of Documents to the Linked Data Web The Document Web: Information Management: A Proposal (TBL, 1989). Built on <ul><li>Documents („Information Resources“)
    6. 6. Untyped HTTP links </li></ul>The Web of Linked Open Data can be understood as an extension of the document web <ul><li>In syntax (RDF)
    7. 7. In scope (including re- presentations of non- information resources, 'things', 'data') </li></ul>
    8. 8. Syntactically Extending the Document Web (1) <ul><li>We add a syntax for making statements on resources: RDF </li></ul><ul><li>Or, more generally triples ... </li></ul><ul><li>… where S and P are web resources (identified using URIs) and O is either a web resource or a literal </li></ul>
    9. 9. Syntactically Extending the Document Web (2) <ul><li>We add a schema language (RDFS) with elements such as </li><ul><li>classes,
    10. 10. hierarchies of classes and properties,
    11. 11. inheritance
    12. 12. support for basic inferencing. </li></ul><li>And thus are able to establish structures in triple aggregations resulting in lightweight domain ontologies: </li></ul>
    13. 13. Extending the Web in Scope: the way it does not work! Taken from Ronald Carpentier's Blog at 2007/08/08/1-2-3/ Something is wrong with this picture (but what?)
    14. 14. … and the way extending the Web in scope is actually done: A Web of Things
    15. 15. … Linked Data Copyright © 2008 W3C (MIT, ERCIM, Keio) Standard Identifiers Standard Pointers Standards for Queries and Statements Link to Context
    16. 16. A few Bubbles: 5/2007 < Over 500 million RDF triples < Around 120,000 RDF links between data sources © Richard Cyganiak
    17. 17. Quite some Bubbles: 9/2008 © Richard Cyganiak
    18. 18. Many Bubbles: 7/2009 © Richard Cyganiak < Over 13.1 billion RDF triples < Over 142 million RDF links between data sources
    19. 19. (Too?) Many Bubbles: 9/2010
    20. 20. <ul>EDM and Linked Open Data </ul><ul>Europeana Information Space </ul><ul>Context Data </ul><ul><li>DBpedia
    21. 21. PND and SWD (prototype)
    22. 22. Geonames
    23. 23. LCSH
    24. 24. … </li></ul>
    25. 25. Linking Open Data <ul><li>Initiative of the Semantic Web Education and Outreach (SWEO) interest group of W3C
    26. 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. 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. 28. Current discussion: how to switch from mere volume to quality ? Matching, mapping and referrals are central
    29. 29. Tom Heath and Christian Bizer (2011) Linked Data: Evolving the Web into a Global Data Space (1st edition). Morgan & Claypool. </li></ul>
    30. 30. LOD2 <ul><li>Large-scale integrating project co-funded by the European Commission within the FP7 framework (09/2010 – 08/2014, Total Budget: 8,58 M€, Total Funding: 6,45 M€, Total Resources: 844 PM) ->
    31. 31. Builds on the Linked Open Data cloud and extends it with a technology stack for enabling application building . The stack includes: </li><ul><li>Comprehensive Knowledge Archive Network (CKAN, registry)
    32. 32. D2R Server (Relational to RDF)
    33. 33. DBPedia Extraction from Wikipedia
    34. 34. OntoWiki (agile, distributed knowledge engineering)
    35. 35. Silk Link Discovery Framework
    36. 36. Openlink Virtuoso (data, information, and knowledge management) </li></ul><li>Consortium: Universität Leipzig (Sören Auer, lead), Centrum Wiskunde & Informatica, Digital Enterprise Research Institut (DERI), Freie Universität Berlin, OpenLink Software, Semantic Web Company, TenForce, Exalead, Wolters Kluwer, Open Knowledge Foundation </li></ul>
    37. 37. <ul>… and the political bit </ul>
    38. 38. On the Importance of being 'Open' (1) <ul><li>“ Openness (allowing access) is separate question.” (TBL,
    39. 39. Does Linked Data work without being 'open' ? </li><ul><li>Technically speaking: yes (cf. pharma industry or biomedical data)
    40. 40. But it gets quite expensive that way …
    41. 41. … much too expensive, probably, for Europeana to afford!
    42. 42. Or else (LD behind a proxy) it is straightaway parasitic.
    43. 43. And much of its 'semantic' charms of open flow of RDF statements and reasoning potential would be lost in such a setting, anyway. </li></ul><li>As a consequence, we aim at Europeana data being Open Linked Data (more in a Europeana Foundation statement at ) and at Europeana data being under CC0! </li></ul>
    44. 44. On the Importance of being 'Open' (2) <ul><li>This has a number of implications </li><ul><li>No control over data usage
    45. 45. No income to be generated from data access and use
    46. 46. Innovative and (commercially) attractive services can be built on LoD </li></ul><li>-> Do not repeat mistakes we are very familiar with from the Open Access debates of the past 10 years! </li><ul><li>'open' = 'free',
    47. 47. 'free' vs. 'commercial' </li></ul><li>-> Do not exclude commercial reuse for Europeana metadata!
    48. 48. -> What is the actual value of context (in business terms!)? </li></ul>
    49. 49. Thank you for your attention!