A Framework for Developing Context-aware Systems

Context-aware computing refers to a general class of mobile real-time reactive systems that continuously sense their physical environment, and adapt their behavior accordingly. Context-awareness is an essential inherent property of ubiquitous computing or pervasive computing systems. Such systems are much richer and more complex than many software systems. The richness mainly comes from context-awareness, the heterogeneity of mobile devices and their service types, while complexity arises in the multitude of adaptations enforced by system policies. In order to provide the true intended effect on the application of services without compromising on the richness, the complexity must be tamed. Towards this goal, this paper proposes a component-based architecture for a Context-aware Framework in which context, awareness capabilities, reactions, and adaptations are formally dealt with. Two formal languages are designed to express context situations and express workflow policies, which respectively lead to a context reasoner and to enforce adaptations.With these formalisms and a component design that can be formalized, this work fulfills a formal approach to construct context-aware applications. Two case studies are explained, of which one is a proof-of-concept case study from service-oriented domain. It is fully implemented to illustrate the expressiveness of the framework design and robustness of its implementation.