WAI › Schedule › 2014 › 20 jan

Title : The Large Scale Structure of Knowledge

Presenter Frank van Harmelen
Abstract The Large Scale Structure of Knowledge What are the laws that govern the structure of very large knowledge bases? Can we discover any regularities in the structure of very large knowledge bases? Can we exploit these regularities to build better inference algorithms? For increasing the graphs' robustness against inconsistency? After more than 2000 years of logic, we have a very good understanding of the small scale structure of knowledge: inference rules, model-theoretic semantics, notions of inconsistency, of soundness and completeness. But we know very little about the structure of very large knowledge bases. Fortunately, since only a few years we actually have such very large knowledge bases, containing tens or even hundreds of millions of facts and rules about tens of millions of objects. We propose a systematic study of such very large knowledge graphs, to discover the laws that govern their structure, and to find out how we can exploit these laws to our advantage.

Title : Extensional Concept Drift in the Dutch Historical Censuses

Presenter Albert Meroño Peñuela
Abstract The world changes continuously and, consequently, concepts also change their meaning over time: we call this phenomenon "concept drift". Extensional concept drift is one type of change of meaning that affects the things the concept extends to. It occurs frequently in historical statistical datasets, and it can have drastic consequences in longitudinal querying. In this talk I will show our work in progress in detecting extensional concept drift in the Dutch historical censuses, reviewing how we published the entire dataset as RDF Data Cube and tracing the census concepts that likely changed the most in the end of the 19th century.