Hereby we announce the release of DBpedia 2016-04. The new release is based on updated Wikipedia dumps dating from March/April 2016 featuring a significantly expanded base of information as well as richer and (hopefully) cleaner data based on the DBpedia ontology.
During the latest DBpedia meeting in Leipzig we discussed about ways to support DBpedia and what benefits this support would bring. For the next two months, we are aiming to raise money to support the hosting of the main services and the next DBpedia release (especially to shorten release intervals). On top of that we need to buy a new server to host DBpedia Spotlight that was so generously hosted so far by third parties. If you use DBpedia and want us to keep going forward, we kindly invite you to donate here or become a member of the DBpedia association.
The English version of the DBpedia knowledge base currently describes 6.0M entities of which 4.6M have abstracts, 1.53M have geo coordinates and 1.6M depictions. In total, 5.2M resources are classified in a consistent ontology, consisting of 1.5M persons, 810K places (including 505K populated places), 490K works (including 135K music albums, 106K films and 20K video games), 275K organizations (including 67K companies and 53K educational institutions), 301K species and 5K diseases. The total number of resources in English DBpedia is 16.9M that, besides the 6.0M resources, includes 1.7M skos concepts (categories), 7.3M redirect pages, 260K disambiguation pages and 1.7M intermediate nodes.
Altogether the DBpedia 2016-04 release consists of 9.5 billion (2015-10: 8.8 billion) pieces of information (RDF triples) out of which 1.3 billion (2015-10: 1.1 billion) were extracted from the English edition of Wikipedia, 5.0 billion (2015-04: 4.4 billion) were extracted from other language editions and 3.2 billion (2015-10: 3.2 billion) from DBpedia Commons and Wikidata. In general, we observed a growth in mapping-based statements of about 2%.
The DBpedia community added new classes and properties to the DBpedia ontology via the mappings wiki. The DBpedia 2016-04 ontology encompasses:
- 754 classes (DBpedia 2015-10: 739)
- 1,103 object properties (DBpedia 2015-10: 1,099)
- 1,608 datatype properties (DBpedia 2015-10: 1,596)
- 132 specialized datatype properties (DBpedia 2015-10: 132)
- 410 owl:equivalentClass and 221 owl:equivalentProperty mappings external vocabularies (DBpedia 2015-04: 407 – 221)
The editor community of the mappings wiki also defined many new mappings from Wikipedia templates to DBpedia classes. For the DBpedia 2016-04 extraction, we used a total of 5800 template mappings (DBpedia 2015-10: 5553 mappings). For the second time the top language, gauged by the number of mappings, is Dutch (646 mappings), followed by the English community (604 mappings).
- In addition to normalized datasets to English DBpedia (en-uris) we additionally provide normalized datasets based on the DBpedia Wikidata (DBw) datasets (wkd-uris). These sorted datasets will be the foundation for the upcoming fusion process with wikidata. The DBw-based uris will be the only ones provided from the following releases on.
- We now filter out triples from the Raw Infobox Extractor that are already mapped. E.g. no more “<x> dbo:birthPlace <z>” and “<x> dbp:birthPlace|dbp:placeOfBirth|… <z>” in the same resource. These triples are now moved to the “infobox-properties-mapped” datasets and not loaded on the main endpoint. See issue 22 for more details.
- Major improvements in our citation extraction. See here for more details.
- We incorporated the statistical distribution approach of Heiko Paulheim in creating type statements automatically and providing them as an additional datasets (instance_types_sdtyped_dbo).
In case you missed it, what we changed in the previous release (2015-10):
- English DBpedia switched to IRIs. This can be a breaking change to some applications that need to change their stored DBpedia resource URIs / links. We provide the “uri-same-as-iri” dataset for English to ease the transition.
- The instance-types dataset is now split into two files: instance-types (containing only direct types) and instance-types-transitive containing the transitive types of a resource based on the DBpedia ontology
- The mappingbased-properties file is now split into three (3) files:
- “geo-coordinates-mappingbased” that contains the coordinated originating from the mappings wiki. the “geo-coordinates” continues to provide the coordinates originating from the GeoExtractor
- “mappingbased-literals” that contains mapping based fact with literal values
- “mappingbased-objects” that contains mapping based fact with object values
- the “mappingbased-objects-disjoint-[domain|range]” are facts that are filtered out from the “mappingbased-objects” datasets as errors but are still provided
- We added a new extractor for citation data that provides two files:
- citation links: linking resources to citations
- citation data: trying to get additional data from citations. This is a quite interesting dataset but we need help to clean it up
- All datasets are available in .ttl and .tql serialization (nt, nq dataset were neglected for reasons of redundancy and server capacity).
- Dataset normalization: We are going to normalize datasets based on wikidata uris and no longer on the English language edition, as a prerequisite to finally start the fusion process with wikidata.
- RML Integration: Wouter Maroy did already provide the necessary groundwork for switching the mappings wiki to a RML based approach on Github. We are not there yet but this is at the top of our list of changes.
- Starting with the next release we are adding datasets with NIF annotations of the abstracts (as we already provided those for the 2015-04 release). We will eventually extend the NIF annotation dataset to cover the whole Wikipedia article of a resource.
- SDTypes: We extended the coverage of the automatically created type statements (instance_types_sdtyped_dbo) to English, German and Dutch (see above).
- Extensions: In the extension folder (2016-04/ext) we provide two new datasets, both are to be considered in an experimental state:
- DBpedia World Facts: This dataset is authored by the DBpedia association itself. It lists all countries, all currencies in use and (most) languages spoken in the world as well as how these concepts relate to each other (spoken in, primary language etc.) and useful properties like iso codes (ontology diagram). This Dataset extends the very useful LEXVO dataset with facts from DBpedia and the CIA Factbook. Please report any error or suggestions in regard to this dataset to Markus.
- Lector Facts: This experimental dataset was provided by Matteo Cannaviccio and demonstrates his approach to generating facts by using common sequences of words (i.e. phrases) that are frequently used to describe instances of binary relations in a text. We are looking into using this approach as a regular extraction step. It would be helpful to get some feedback from you.
Lots of thanks to
- Markus Freudenberg (University of Leipzig / DBpedia Association) for taking over the whole release process and creating the revamped download & statistics pages.
- Dimitris Kontokostas (University of Leipzig / DBpedia Association) for conveying his considerable knowledge of the extraction and release process.
- All editors that contributed to the DBpedia ontology mappings via the Mappings Wiki.
- The whole DBpedia Internationalization Committee for pushing the DBpedia internationalization forward.
- Heiko Paulheim (University of Mannheim) for providing the necessary code for his algorithm to generate additional type statements for formerly untyped resources and identify and removed wrong statements. Which is now part of the DIEF.
- Václav Zeman, Thomas Klieger and the whole LHD team (University of Prague) for their contribution of additional DBpedia types
- Marco Fossati (FBK) for contributing the DBTax types
- Alan Meehan (TCD) for performing a big external link cleanup
- Aldo Gangemi (LIPN University, France & ISTC-CNR, Italy) for providing the links from DOLCE to DBpedia ontology.
- Kingsley Idehen, Patrick van Kleef, and Mitko Iliev (all OpenLink Software) for loading the new data set into the Virtuoso instance that provides 5-Star Linked Open Data publication and SPARQL Query Services.
- OpenLink Software (http://www.openlinksw.com/) collectively for providing the SPARQL Query Services and Linked Open Data publishing infrastructure for DBpedia in addition to their continuous infrastructure support.
- Ruben Verborgh from Ghent University – iMinds for publishing the dataset as Triple Pattern Fragments, and iMinds for sponsoring DBpedia’s Triple Pattern Fragments server.
- Ali Ismayilov (University of Bonn) for extending the DBpedia Wikidata dataset.
- Vladimir Alexiev (Ontotext) for leading a successful mapping and ontology clean up effort.
- All the GSoC students and mentors which directly or indirectly influenced the DBpedia release
- Special thanks to members of the DBpedia Association, the AKSW and the department for Business Information Systems of the University of Leipzig.
The work on the DBpedia 2016-04 release was financially supported by the European Commission through the project ALIGNED – quality-centric, software and data engineering (http://aligned-project.eu/). More information about DBpedia is found at http://dbpedia.org as well as in the new overview article about the project available at http://wiki.dbpedia.org/Publications.
Have fun with the new DBpedia 2016-04 release!