DBpedia Knowledge Base

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A DBpedia Knowledge Base is a open shallow general and cross-domain knowledge graph produced by the DBpedia project.



References

2013

  • http://en.wikipedia.org/wiki/DBpedia#Dataset
    • As of September 2011, the DBpedia dataset describes more than 3.64 million things, out of which 1.83 million are classified in a consistent ontology, including 416,000 persons, 526,000 places, 106,000 music albums, 60,000 films, 17,500 video games, 169,000 organizations, 183,000 species and 5,400 diseases. The DBpedia data set features labels and abstracts for these 3.64 million things in up to 97 different languages; 2,724,000 links to images and 6,300,000 links to external web pages; 6,200,000 external links into other RDF datasets, 740,000 Wikipedia categories, and 2,900,000 YAGO2 categories. From this dataset, information spread across multiple pages can be extracted, for example book authorship can be put together from pages about the work, or the author.

      The DBpedia project uses the Resource Description Framework (RDF) to represent the extracted information. As of September 2011, the DBpedia dataset consists of over 1 billion pieces of information (RDF triples) out of which 385 million were extracted from the English edition of Wikipedia and 665 million were extracted from other language editions.[1]

      One of the challenges in extracting information from Wikipedia is that the same concepts can be expressed using different parameters in infobox and other templates, such as |birthplace= and |placeofbirth=. Because of this, queries about where people were born would have to search for both of these properties in order to get more complete results. As a result, the DBpedia Mapping Language has been developed to help in mapping these properties to an ontology while reducing the number of synonyms. Due to the large diversity of infoboxes and properties in use on Wikipedia, the process of developing and improving these mappings has been opened to public contributions.

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  • http://dbpedia.org/About
    • … Knowledge bases are playing an increasingly important role in enhancing the intelligence of Web and enterprise search and in supporting information integration. Today, most knowledge bases cover only specific domains, are created by relatively small groups of knowledge engineers, and are very cost intensive to keep up-to-date as domains change. At the same time, Wikipedia has grown into one of the central knowledge sources of mankind, maintained by thousands of contributors.

      The DBpedia project leverages this gigantic source of knowledge by extracting structured information from Wikipedia and by making this information accessible on the Web under the terms of the Creative Commons Attribution-ShareAlike 3.0 License and the GNU Free Documentation License.


  • http://wiki.dbpedia.org/Datasets
    • The DBpedia data set uses a large multi-domain ontology which has been derived from Wikipedia. The English version of the DBpedia 3.8 data set describes 3.77 million “things” with 400 million “facts”.

      In addition, we provide localized versions of DBpedia in 111 languages. All these versions together describe 20.8 million things, out of which 10.5 million overlap (are interlinked) with concepts from the English DBpedia. The full DBpedia data set features labels and abstracts for 10.3 million unique things in up to 111 different languages; 8.0 million links to images and 24.4 million HTML links to external web pages; 27.2 million data links into external RDF data sets, 55.8 million links to Wikipedia categories, and 8.2 million YAGO categories. The dataset consists of 1.89 billion pieces of information (RDF triples) out of which 400 million were extracted from the English edition of Wikipedia, 1.46 billion were extracted from other language editions, and about 27 million are data links to external RDF data sets.


  • http://dbpedia.org/Ontology The DBpedia Ontology (3.8)
    • The DBpedia Ontology is a shallow, cross-domain ontology, which has been manually created based on the most commonly used infoboxes within Wikipedia. The ontology currently covers 359 classes which form a subsumption hierarchy and are described by 1,775 different properties.

      With the DBpedia 3.2 release, we introduced a new infobox extraction method which is based on hand-generated mappings of Wikipedia infoboxes to the DBpedia ontology. The mappings define fine-granular rules on how to parse infobox values. The mappings also address weaknesses in the Wikipedia infobox system, like having different infoboxes for the same class, using different property names for the same property, and not having clearly defined datatypes for property values. Therefore, the instance data within the infobox ontology is much cleaner and better structured than the infobox data within the DBpedia infobox dataset which is generated using the old infobox extraction code.

      With the DBpedia 3.5 release, we introduced a public wiki for writing infobox mappings, editing existing ones as well as editing the DBpedia ontology. This allows external contributors to define mappings for the infoboxes they are interested in and to extend the existing DBpedia ontology with additional classes and properties.

      Since the DBpedia 3.7 release, the ontology is a directed-acyclic graph, not a tree. Classes may have multiple superclasses, which was important for the mappings to schema.org. A taxonomy can still be constructed by ignoring all superclasses but the one that is specified first in the list and is considered the most important.