we are happy to announce the release of DBpedia 3.5. The new release is based on Wikipedia dumps dating from March 2010. Compared to the 3.4 release, we were able to increase the quality of the DBpedia knowledge base by employing a new data extraction framework which applies various data cleansing heuristics as well as by extending the infobox-to-ontology mappings that guide the data extraction process.
The new DBpedia knowledge base describes more than 3.4 million things, out of which 1.47 million are classified in a consistent ontology, including 312,000 persons, 413,000 places, 94,000 music albums, 49,000 films, 15,000 video games, 140,000 organizations, 146,000 species and 4,600 diseases. The DBpedia data set features labels and abstracts for these 3.2 million things in up to 92 different languages; 1,460,000 links to images and 5,543,000 links to external web pages; 4,887,000 external links into other RDF datasets, 565,000 Wikipedia categories, and 75,000 YAGO categories. The DBpedia knowledge base altogether consists of over 1 billion pieces of information (RDF triples) out of which 257 million were extracted from the English edition of Wikipedia and 766 million were extracted from other language editions.
The new release provides the following improvements and changes compared to the DBpedia 3.4 release:
- The DBpedia extraction framework has been completely rewritten in Scala. The new framework dramatically reduces the extraction time of a single Wikipedia article from over 200 to about 13 milliseconds. All features of the previous PHP framework have been ported. In addition, the new framework can extract data from Wikipedia tables based on table-to-ontology mappings and is able to extract multiple infoboxes out of a single Wikipedia article. The data from each infobox is represented as a separate RDF resource. All resources that are extracted from a single page can be connected using custom RDF properties which are also defined in the mappings. A lot of work also went into the value parsers and the DBpedia 3.5 dataset should therefore be much cleaner than its predecessors. In addition, units of measurement are normalized to their respective SI unit, which makes querying DBpedia easier.
- The mapping language that is used to map Wikipedia infoboxes to the DBpedia Ontology has been redesigned. The documentation of the new mapping language is found at http://dbpedia.svn.sourceforge.net/viewvc/dbpedia/trunk/extraction/core/doc/mapping%20language/
- In order to enable the DBpedia user community to extend and refine the infobox to ontology mappings, the mappings can be edited on the newly created wiki hosted on http://mappings.dbpedia.org. At the moment, 303 template mappings are defined, which cover (including redirects) 1055 templates. On the wiki, the DBpedia Ontology can be edited by the community as well. At the moment, the ontology consists of 259 classes and about 1,200 properties.
- The ontology properties extracted from infoboxes are now split into two data sets (For details see: http://wiki.dbpedia.org/Datasets): 1. The Ontology Infobox Properties dataset contains the properties as they are defined in the ontology (e.g. length). The range of a property is either an xsd schema type or a dimension of measurement, in which case the value is normalized to the respective SI unit. 2. The Ontology Infobox Properties (Specific) dataset contains properties which have been specialized for a specific class using a specific unit. e.g. the property height is specialized on the class Person using the unit centimeters instead of meters.
- The framework now resolves template redirects, making it possible to cover all redirects to an infobox on Wikipedia with a single mapping.
- Three new extractors have been implemented: 1. PageIdExtractor extracting Wikipedia page IDs are extracted for each page. 2. RevisionExtractor extracting the latest revision of a page. 3. PNDExtractor extracting PND (Personnamendatei) identifiers.
- The data set now provides labels, abstracts, page links and infobox data in 92 different languages, which have been extracted from recent Wikipedia dumps as of March 2010.
- In addition the N-Triples datasets, N-Quads datasets are provided which include a provenance URI to each statement. The provenance URI denotes the origin of the extracted triple in Wikipedia (For details see: http://wiki.dbpedia.org/Datasets).You can download the new DBpedia dataset from http://wiki.dbpedia.org/Downloads35. As usual, the data set is also available as Linked Data and via the DBpedia SPARQL endpoint.
Lots of thanks to:
- Robert Isele, Anja Jentzsch, Christopher Sahnwaldt, and Paul Kreis (all Freie Universität Berlin) for reimplementing the DBpedia extraction framework in Scala, for extending the infobox-to-ontology mappings and for extracting the new DBpedia 3.5 knowledge base.
- Jens Lehmann and Sören Auer (both Universität Leipzig) for providing the knowledge base via the DBpedia download server at Universität Leipzig.
- Kingsley Idehen and Mitko Iliev (both OpenLink Software) for loading the knowledge base into the Virtuoso instance that serves the Linked Data view and SPARQL endpoint.
The whole DBpedia team is very thankful to three companies which enabled us to do all this by supporting and sponsoring the DBpedia project:
- Neofonie GmbH (http://www.neofonie.de/index.jsp), a Berlin-based company offering leading technologies in the area of Web search, social media and mobile applications.
- Vulcan Inc. as part of its Project Halo (www.projecthalo.com). Vulcan Inc. creates and advances a variety of world-class endeavors and high impact initiatives that change and improve the way we live, learn, do business (http://www.vulcan.com/).
- OpenLink Software (http://www.openlinksw.com/). OpenLink Software develops the Virtuoso Universal Server, an innovative enterprise grade server that cost-effectively delivers an unrivaled platform for Data Access, Integration and Management.
More information about DBpedia is found at http://dbpedia.org/About
Have fun with the new DBpedia knowledge base!