Enhancing situation-aware systems through imprecise reasoning

Context awareness (CA) is viewed as one of the most important aspects in the emerging pervasive computing paradigm. We focus our work on situation awareness (SA)-a more holistic variant of CA where situations are regarded as logically aggregated contexts. One important problem that arises in such systems is the imperfect observations (e.g., sensor readings) that lead to the estimation of the current context of the user. Hence, the knowledge upon which the context/situation aware paradigm is built is rather vague. To deal with this shortcoming, we propose the use of Fuzzy Logic theory with the purpose of determining (inferring) and reasoning about the current situation of the involved user. We elaborate on the architectural model that enables the system to assume actions autonomously according to previous user reactions and current situation. The captured imperfect contextual information is matched against predeveloped ontologies in order to approximately infer the current situation of the user. Finally, we present a series of experimental results that provide evidence of the flexible efficient nature of the proposed SA architecture.