Complex Event Recognition Group
The Complex Event Recognition (CER) group of NCSR "Demokritos" works towards advanced and efficient methods for the recognition of complex events in a multitude of large, heterogeneous and interdependent data streams. In particular, we are developing novel CER methods, which take as input streams of low-level events, e.g. sensor-based events, such as a change in temperature, and combine them to infer complex high-level events of interest, such as the start of a fire incident or a fault in the cooling system of a vehicle. Our approach is primarily based on the Event Calculus, a simple logic-based formalism that supports effective reasoning about complex events. In addition to its formal semantics, this approach has allowed us to develop efficient real-time recognition methods, as well as to combine logic-based with statistical reasoning, in order to handle the inherent uncertainty of most event recognition applications. Furthermore, it lends itself directly to the development of machine learning methods for acquiring logic-based event descriptions from data.