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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)
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
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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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
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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.
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• DBpedia Server
• Ontology storage
• Mapping validation
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35. Google Summer of Code [2013]
Mapping from DBpedia to Wikidata properties
• Dump from Wikidata facts with mapped properties and dataypes
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• 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
