Interactive reasoning in uncertain RDF knowledge bases

Abstract

Recent advances in Web-based information extraction have allowed for the automatic construction of large, semantic knowledge bases, which are typically captured in RDF format. The very nature of the applied extraction techniques however entails that the resulting RDF knowledge bases may face a significant amount of incorrect, incomplete, or even inconsistent (i.e., uncertain) factual knowledge, which makes query answering over this kind of data a challenge. Our reasoner, coined URDF, supports SPARQL queries along with rule-based, first-order predicate logic to infer new facts and to resolve data uncertainty over millions of RDF triplets directly at query time. We demonstrate a fully interactive reasoning engine, combining a Java-based reasoning backend and a Flash-based visualization frontend in a dynamic client-server architecture. Our visualization frontend provides interactive access to the reasoning backend, including tasks like exploring the knowledge base, rule-based and statistical reasoning, faceted browsing of large query graphs, and explaining answers through lineage. © 2011 ACM.