WhoKnows? Evaluating linked data heuristics with a quiz that cleans up DBpedia

Semantic technologies enable sophisticated search scenarios on educational video content. Linking Open Data (LOD) provides a vast amount of well structured semantic information in heterogenous domains. But, despite of the syntactically well expressed RDF facts, when authoring and publishing LOD, many inconsistencies may occur, especially if the data is generated with the help of automated methods. Data cleansing approaches enable to detect inconsistencies and to overhaul affected data sets, but they are difficult to apply automatically. Also manual reviewing is hardly possible because of the tremendous size of already existing LOD resources. To overcome this, we propose a collaborative reviewing approach, which motivates the reviewer in a playful manner. This paper presents WhoKnows? , an online quiz that generates different kinds of questionnaires from DBpedia data sets. Besides its playfulness, WhoKnows? has been developed for the evaluation of property relevance ranking heuristics on DBpedia data with the convenient side effect of detecting inconsistencies and doubtful facts.