This document discusses DBpedia, a project that extracts structured data from Wikipedia and publishes it as linked open data on the web. It summarizes key points about DBpedia, including that it extracts over 4 million things from Wikipedia and publishes them as over 2.4 billion RDF triples with links to images, web pages, and other datasets. It also describes the DBpedia Mappings Wiki, which allows collaborative editing of mappings from Wikipedia infoboxes to an ontology to increase data quality. Finally, it outlines some ongoing and future work, such as multilingual data integration and using DBpedia as background knowledge for NLP tasks.

1.
DBpedia Mappings Wiki
Anja Jentzsch - @anjeve
Hasso-Plattner-Institute, Potsdam, Germany
!
SMWCon Fall 2013
2103/10/30

2. Linked Data Principles
Set of best practices for publishing structured data on the Web in
accordance with the general architecture of the Web.
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Use URIs as names for things.
Use HTTP URIs so that people can look up those names.
When someone looks up a URI, provide useful RDF information.
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

3. Properties of the Web of Linked Data
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Global, distributed dataspace build on a simple set of standards
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RDF, URIs, HTTP
Entities are connected by links
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creating a global data graph that spans data sources and
enables the discovery of new data sources
Provides for data-coexistence
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Everyone can publish data to the Web of Linked Data
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Everyone can express their personal view on things
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Everybody can use the vocabularies/schemas that they like

4. W3C Linking Open Data Project [2007]
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Grassroots community effort to
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publish existing open license datasets as Linked Data on the Web
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interlink things between different data sources

5. LOD Data Sets on the Web: September 2011
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295 data sets
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Over 31 billion RDF triples
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Over 504 million RDF links between data sources
http://lod-cloud.net

6. LOD Data Set statistics
LOD Cloud Data Catalog on the Data Hub
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http://datahub.io/group/lodcloud
More statistics
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http://lod-cloud.net/state/

7. DBpedia [2007]
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DBpedia is a joint project with the following goals
• extracting structured information from Wikipedia
• publish this information under an open license on the Web
• setting links to other data sources
!
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Partners
• Universität Mannheim (Germany)
• Universität Leipzig (Germany)
• OpenLink Software (UK)

8. Extracting structured data from Wikipedia

9. Extracting structured data from Wikipedia
dbpedia:Berlin
rdf:type
dbpedia-owl:City ,
dbpedia-owl:PopulatedPlace ,
dbpedia-owl:Place ;
rdfs:label
"Berlin"@en , "Berlino"@it ;
dbpedia-owl:population
wgs84:lat
wgs84:long
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52.500557 ;
13.398889 .
dbpedia:SoundCloud
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3499879 ;
dbpedia-owl:location
Access to DBpedia data:
• Dumps
• SPARQL endpoint
• Linked Data interface
dbpedia:Berlin .

10. The DBpedia Data Set
Information on more than 4 million “things”
• 832,000 persons
• 209,000 organisations
• 639,000 places
• 116,000 music albums
• 78,000 movies
• 226,000 species
• overall more than 2.4 billion RDF triples
• localised versions in 119 languages
• 24.6 million links to images
• 27.6 million links to external web pages
• 45 million links to other Linked Data sets
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11. DBpedia Use Cases
1. Hub for the growing Web of Data
2. Data source for applications and mashups
3. Improvement of Wikipedia search
4. Text analysis and annotation

13. DBpedia Mobile
displays Wikipedia data on map
• aggregates different data sources
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14. Faceted Wikipedia Search
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faceted browsing and free text search

16. http://spotlight.dbpedia.org

17. DBpedia Information Extraction
Framework (DIEF)
Open source: http://github.com/dbpedia
• More than 30 developers
• Written in Scala & Java
• Can be adapted to other MediaWikis
• adaption to Wiktionary http://wiktionary.dbpedia.org
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18. DIEF Architecture

19. DIEF
Simple approach, huge generality
• Inconsistency in property naming
• Different infobox properties can have different names for the same
meaning (e.g. born vs birth_date vs birthDate)
• Inconsistency in property data types
• Data types are determined by resource with a simple greedy algorithm
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20. Mapping-Based Infobox Extraction
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Correct semantics
• Combine what belongs together (birth_place, Geburtsort)
• Divide what is different (born, Geburtsort)
• Huge impact on precision & recall

21. DBpedia Mappings Wiki
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since March 2010 collaborative editing of
• DBpedia ontology
• mappings from Wikipedia infoboxes and tables to DBpedia ontology
curated in a public wiki with instant validation methods
• http://mappings.dbpedia.org
multi-langual mappings to the DBpedia ontology:
• ar, bg, bn, ca, cs, de, el, en, es, et, eu, fr, ga, hi, hr, hu, it, ja, ko, nl, pl, pt, ru, sl,
tr
!
allows for a significant increase of the extracted data’s quality
• each domain has its experts
~ 170 active editors

22. DBpedia Mappings Wiki Details
MediaWiki plus
• Extensions for
• validating mappings
• storing and validating the ontology
• Templates for
• ontology definition
• mapping infoboxes to the ontology
• custom templates: date intervals, conditions, geo coordinates etc.
!
• DBpedia Server
• Ontology storage
• Mapping validation
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27. Classes and Properties

30. Test Mappings

31. Validate Mappings

32. DBpedia 3.9 Mapping Statistics
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3177 template mappings
529 classes
927 object properties
1,290 datatype properties
116 specialized datatype properties
46 owl:equivalentClass and 31 owl:equivalentProperty mappings to http://
schema.org

33. DBpedia Mapping Edits

34. DBpedia Mapping Coverage

35. Google Summer of Code [2013]
Mapping from DBpedia to Wikidata properties
• Dump from Wikidata facts with mapped properties and dataypes
!
• http://wiki.dbpedia.org/gsoc2013/ideas/WikidataMappings
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36. Ongoing & Future Work
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Multilingual data integration and fusion
Community-driven data quality improvement
Inline extraction
DBpedia and NLP
• structured background knowledge for e.g. named entity recognition and
disambiguation
Collaboration between Wikidata and DBpedia

37. Thanks!
Email: anja@anjeve.de
Twitter: @anjeve
References:
• DBpedia http://dbpedia.org
• DBpedia Mappings Wiki http://mappings.dbpedia.org
• LOD Cloud http://lod-cloud.net
• LOD Data Set Catalogue http://www.datahub.io/group/lodcloud