Semantic MediaWiki

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Semantic MediaWiki (SMW) is an extension of MediaWiki – the wiki-system powering Wikipedia – with semantic technology, thus turning it into a semantic wiki. This wiki (the one you're just using) is usually running on the most recent version of the Semantic MediaWiki extensions, and thus also serves as a demonstration for the system. Semantic MediaWiki is used on many other sites and has also been featured in the press.

Using SMW


SMW in the Semantic Web

What is this all about?

Semantic MediaWiki introduces some additional markup into the wiki-text which allows users to add "semantic annotations" to the wiki. While this first appears to make things more complex, it can also greatly simplify the structure of the wiki, help users to find more information in less time, and improve the overall quality and consistency of the wiki. To illustrate this, we provide some examples from the daily business of Wikipedia:

  1. Manually generated lists. Wikipedia is full of manually edited listings such as this one. Those lists are prone to errors, since they have to be updated manually. Furthermore, the number of potentially interesting lists is huge, and it is impossible to provide all of them in acceptable quality. In SMW, lists are generated automatically like this. They are always up-to-date and can easily be customized to obtain further information.
  2. Searching information. Much of Wikipedia's knowledge is hopelessly burried within millions of pages of text, and can hardly be retrieved at all. For example, at the time of this writing, there is no list of female physicists in Wikipedia. When trying to find all women of this profession that are featured in Wikipedia, one has to resort to textual search. Obviously, this attempt is doomed to fail miserably. Note that among the 20 first results, only 5 are about people at all, and that Marie Curie is not contained in the whole result set (since "female" does not appear on her page). Again, querying in SMW easily solves this problem (in this case even without further annotation, since existing categories suffice to find the results).
  3. Inflationary use of categories. The need for better structuring becomes apparent by the enormous use of categories in Wikipedia. While this is generally helpful, it has also lead to a number of categories that would be mere query results in SMW. For some examples consider the categories Rivers in Buckinghamshire, Asteroids named for people, and 1620s deaths, all of which could easily be replaced by simple queries that use just a handful of annotations. Indeed, in this example Category:Rivers, Relation:located in, Category:Asteroids, Category:People, Relation:named after, and Attribute:date of death would suffice to create thousands of similar listings on the fly, and to remove hundreds of Wikipedia categories.
  4. Inter-language consistency. Most articles in Wikipedia are linked to according pages in different languages, and this can be done for SMW's semantic annotation as well. With this knowledge, you can ask for the population of Bejing that is given in Chinese Wikipedia without reading a single word of this language. This can be exploited to detect possible inconsistencies that can then be resolved by editors. For example, the population of Edinburgh at the time of this writing is different in English, German, and French Wikipedia.
  5. External reuse. Some desktop tools today make use of Wikipedia's content, e.g. the media player Amarok displays articles about artists during playback. However, such reuse is limited to fetching some article for immediate reading. The progam cannot exploit the information (e.g. to find songs of artists that have worked for the same label), but can only show the text in some other context. SMW leverages a wiki's knowledge to be useable outside the context of its textual article. Since semantic data can be published under a free license, it could even be shipped with a software to save bandwidth and download time.
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