Abstract
Reasoning about context is a cornerstone component of mobile systems. These systems are ubiquitous and need to adapt continuously to their surroundings in order to provide high quality interaction with users and to fit with their actual needs. Context-aware systems have emerged as a particular type of mobile systems that can understand the user requirements and accordingly personalize the interaction with the mobile system. Context-aware systems rely mainly on two components: i) a comprehensive context model to represent all the contextual elements surrounding the mobile system, and ii) a reasoning engine that runs a continuous context management process which gathers environment data from sensors and web services, checks the consistency of the context instance and finally updates it. In this paper we show the context model and describe the context reasoning process. The implementation of the system is then presented and illustrated through an example.