Markus Krötzsch

Semantic Wikipedia

Wikipedia is the worlds largest collaboratively edited source of encyclopaedic knowledge. But in spite of its utility, its contents are barely machine-interpretable. Structural knowledge, e.,g. about how concepts are interrelated, can neither be formally stated nor automatically processed. Also the wealth of numerical data is only available as plain text and thus can not be processed by its actual meaning.We provide an extension to be integrated in Wikipedia, that allows the typing of links between articles and the specification of typed data inside the articles in an easy-to-use manner.Enabling even casual users to participate in the creation of an open semantic knowledge base, Wikipedia has the chance to become a resource of semantic statements, hitherto unknown regarding size, scope, openness, and internationalisation. These semantic enhancements bring to Wikipedia benefits of todays semantic technologies: more specific ways of searching and browsing. Also, the RDF export, that gives direct access to the formalised knowledge, opens Wikipedia up to a wide range of external applications, that will be able to use it as a background knowledge base.In this paper, we present the design, implementation, and possible uses of this extension.

Semantic mediawiki

Semantic MediaWiki is an extension of MediaWiki – a widely used wiki-engine that also powers Wikipedia. Its aim is to make semantic technologies available to a broad community by smoothly integrating them with the established usage of MediaWiki. The software is already used on a number of productive installations world-wide, but the main target remains to establish “Semantic Wikipedia” as an early adopter of semantic technologies on the web. Thus usability and scalability are as important as powerful semantic features.

Wikidata: a free collaborative knowledgebase

This collaboratively edited knowledgebase provides a common source of data for Wikipedia, and everyone else.

The two cultures: mashing up web 2.0 and the semantic web

A common perception is that there are two competing visions for the future evolution of the Web: the Semantic Web and Web 2.0. A closer look, though, reveals that the core technologies and concerns of these two approaches are complementary and that each field can and must draw from the others strengths. We believe that future web applications will retain the Web 2.0 focus on community and usability, while drawing on Semantic Web infrastructure to facilitate mashup-like information sharing. However, there are several open issues that must be addressed before such applications can become commonplace. In this paper, we outline a semantic weblogs scenario that illustrates the potential for combining Web 2.0 and Semantic Web technologies, while highlighting the unresolved issues that impede its realization. Nevertheless, we believe that the scenario can be realized in the short-term. We point to recent progress made in resolving each of the issues as well as future research directions for each of the communities.

The two cultures: Mashing up Web 2.0 and the Semantic Web

A common perception is that there are two competing visions for the future evolution of the Web: the Semantic Web and Web 2.0. A closer look, though, reveals that the core technologies and concerns of these two approaches are complementary and that each field can and must draw from the others strengths. We believe that future Web applications will retain the Web 2.0 focus on community and usability, while drawing on Semantic Web infrastructure to facilitate mashup-like information sharing. However, there are several open issues that must be addressed before such applications can become commonplace. In this paper, we outline a semantic weblogs scenario that illustrates the potential for combining Web 2.0 and Semantic Web technologies, while highlighting the unresolved issues that impede its realization. Nevertheless, we believe that the scenario can be realized in the short-term. We point to recent progress made in resolving each of the issues as well as future research directions for each of the communities.

ELP: Tractable Rules for OWL 2

We introduce

Description Logic Rules

\text{\sf{ELP}}

The Incredible ELK

as a decidable fragment of the Semantic Web Rule Language (SWRL) that admits reasoning in polynomial time.

Extending decidable existential rules by joining acyclicity and guardedness

\text{\sf{ELP}}

Conjunctive queries for a tractable fragment of OWL 1.1

is based on the tractable description logic