Prof. Dr. Chris Bizer

Transcription

1 DBpedia and the Web of Data Prof. Dr. Chris Bizer Freie Universität ität Berlin Berlin. November 28, 2008

2 Hello Name Job Chris Bizer Junior- Professor at Freie Universität Berlin Projects RAP - RDF API for PHP (together with Universität Leipzig) D2RQ und D2R Server (together with HP Labs Bristol) Named Graphs and NG4J (together with HP Labs Bristol) Fresnel Display Vocabulary (together with MIT and INRIA) DBpedia (together with Universität Leipzig and OpenLink) Linking Open Data (community project sponsored by W3C)

3 Outline 1. The DBpedia Project 2. The Web of Data 3. Linked Data Deployment on the Web 4. Linked Data Applications 5. What is next?

4 DBpedia DBpedia is a community effort to extract structured information from Wikipedia make this information available on the Web under an open license interlink the DBpedia dataset with other open datasets on the Web Contributors Freie Universität Berlin (Germany) Universität Leipzig (Germany) OpenLink Software (UK)

5 Structured Information in Wikipedia Wikipedia consists of 11.7 million articles (2.62 million in English) in 264 languages monthly growth-rate: 4% Wikipedia articles contain structured information infoboxes which use a template mechanism categorization of the article images depicting the article s topic links to external webpages intra-wiki links to other articles inter-language links to articles about the same topic in different languages

6 Extracting Structured Information from Wikipedia < dbpedia:native_name Calgary ; dbpedia:elevation 1048 ; dbpedia:population_city ; dbpedia:population_metro di t ; mayor_name dbpedia:dave_bronconnier ; governing_body dbpedia:calgary_city_council _ ;... using a PHP extraction framework

7 The DBpedia Dataset Data about 2.6 million things including at least 213,000 persons 328,000 places 57,000 music albums 36,000 films 20,000 companies 80,000 species Altogether 247 million pieces of information (RDF triples) 29 million triples originate from infoboxes 588,000 links to pictures 3,150,000 links to relevant external web pages 4,878,000 RDF links into other databases 414,000 Wikipedia categories 75,000 YAGO categories

8 Multi-Lingual Abstracts The dataset contains a short and a long abstract for each concept. Short abstracts English: 2,600, German: 391,000 French: 383,000 Dutch: 284,000 Polish: 256,000 Italian: 286,000 Spanish: 226,000 Japanese: 199,000 Portuguese: 246,000 Swedish: 144,000 Chinese: 101,000000

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11 Accessing the DBpedia Dataset over the Web 1. SPARQL Endpoint 2. Linked Data Interface 3. Data Dumps for Download

12 The DBpedia SPARQL Endpoint hosted on a OpenLink Virtuoso server can answer SPARQL queries like Give me all Sitcoms that are set in NYC? All German musicians that were born in Berlin in the 19th century? All tennis players from Moscow? All films by Quentin Tarentino? All soccer players with tricot number 11, playing for a club having a stadium with over 40,000 seats and is born in a country with over 10 million inhabitants?

13 Improving Wikipedia Search

14 2. The Web of Data

15 The Web of Documents The Web is a single information space build on open standards d and hyperlinks. Web Browsers Search Engines HTTP HTML HTML HTML hyper hyper links links hyper links HTML A B C D

16 Linked Data Use RDF and HTTP to 1. publish structured data on the Web, 2. set links between data from one data source to data within other data sources. Thing Thing Thing Thing Thing Thing Thing Thing Thing Thing data link data link data link data link A B C D E

17 Linked Data Principles 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 RDF information. 4. Include RDF statements t t that t link to other URIs so that t they can discover related things. Tim Berners-Lee /D /Li t

18 The RDF Data Model pd:cygri rdf:type foaf:person foaf:namef Richard Cyganiak foaf:based_near dbpedia:berlin

19 Data objects are identified with HTTP URIs pd:cygri rdf:type foaf:person foaf:namef Richard Cyganiak foaf:based_near dbpedia:berlin pd:cygri = dbpedia:berlin =

20 Dereferencing 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

21 Dereferencing URIs over 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

22 The Disco Hyperdata Browser

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24 3. Linked Data Deployment on the Web Is this real? Thing Thing Thing Thing Thing Thing Thing Thing Thing Thing typed links typed links typed links typed links A B C D E

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

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

27 LOD Datasets on the Web: August 2007

28 LOD Datasets on the Web: February 2008

29 LOD Datasets on the Web: September 2008

30 Triple Count More than 2 billion RDF triples More than 5 million links between datasets. (rough estimates)

31 Organizations publishing Linked Data Universities and Research Institutes Massachusetts Institute of Technology (USA) University of Southampton (UK) Freie Universität Berlin (DE) DERI (IRE) KMi, Open University (UK) University of London (UK) Universität Hannover (DE) University of Pennsylvania (USA) Universität Leipzig (DE) Universität Karlsruhe (DE) Joanneum (AT) University of Toronto (CA) Companies BBC (UK) OpenLink (UK) Zitgist (USA) Talis (UK) Garlik (UK) Mondeca (FR) Cyc Foundation (USA)

32 The Bio2RDF Project Goals 1. Make bioinformatics data available in RDF format on the Web. 2. Promote the linked data vision within the bioinformatics community. 3. Answer questions which were not possible or practical to ask before. Participants Université Laval, Canada Queensland University of Technology, Australia

33 The Bio2RDF Cloud 27 data sources 260 million records 2,7 billion RDF triples

34 4. 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 typed typed links links links A B C D E

35 Linked Data Browsers Tabulator Browser (MIT, USA) Disco Hyperdata Browser (FU Berlin, DE) OpenLink RDF Browser (OpenLink, UK) Zitgist RDF Browser (Zitgist, USA) Humboldt (HP Labs, UK) Fenfire (DERI, Irland) Marbles (FU Berlin, DE)

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38 Linked Data Mashups Domain-specific ifi applications using Linked Data from the Web

39 DBtune Slashfacet Visualizes music-related Linked Data Uses LastFM, MySpace, and BBC data

40 DBpedia Mobile Geospatial entry point into the Web of Data Starts with DBpedia, Revyu and Flickr data

41 Semantic Web Pipes

42 Web of Data Search Engines Falcons (IWS, China) Sindice (DERI, Ireland) MicroSearch (Yahoo, Spain) Watson (Open University, UK) SWSE (DERI, Ireland) Swoogle (UMBC, USA)

43 Falcons

44 5. What is next for DBpedia?

45 Better Interfaces for Common Wikipedia Users Direction: free-text search + facet-browsing

46 Live Update Current Situation DBpedia update cycle: 3 month Wikimedia Foundation provides us with live update stream Opportunity Increase the currency of the DBpedia dataset using this update stream Result DBpedia in synchronization with Wikipedia.

47 Cross-Language Data Fusion Opportunity there are 264 Wikipedia Editions in different languages. there are cross-language links. the Italian Wikipedia knows more about Italian villages then the English one. the German Wikipedia contains more person infoboxes than the English one. Idea Augment the infobox dataset with facts from other Wikipedia editions. Result A much richer DBpedia dataset.

48 Augment DBpedia with Data from External Sources Opportunity the Linking Open Data cloud provides lots of useful data which is not contained in Wikipedia yet. For instance: Idea - EuroStat provides additional statistical information about countries. - Musicbrainz contains additional information about other bands. - Geonames provides additional information about locations. Augment DBpedia with additional data from external sources. Result A much richer DBpedia dataset.

49 Contribute back to the Wikipedia Community Opportunity augmentation with data from the LOD cloud makes the DBpedia dataset richer than Wikipedia itself. infobox data is extracted from Wikipedia editions in various languages. Idea Extend the Wikipedia authoring environment with - Suggestions for infobox values - Cross-language consistency checking for infoboxes Initialize Wikipedia Clean-Up Cycles Data-driven search interfaces expose the weaknesses of Wikipedia template system. Preferred items not showing up in end-user interfaces may motivate Wikipedia editors to use templates more stringently.

50 What is next for the Web of Data?

51 Linking 1. Increase the amount of links between datasets 2. Increase the quality of these links Today: Simple pattern- and graph-matching based techniques used for automated interlinking. There is lots of existing work in database and knowledge representation communities on identity resolution to be used.

52 Data Fusion Data Object 1 Data Object 2 Application Integrated View Data Object 3 Data Object 4 owl:sameas Data Object 5 Data Object 6 Users want an integrated view on all data that is available a ab about an object! Raises well known but unsolved problems: Schema mapping Inconsistency resolution Trust / information quality owl:sameas A B C

53 Thanks! References DBpedia W3C Linking Open Data Project LinkingOpenData Tutorial: How to Publish Linked Data on the Web wiwiss