A Framework for Developing Context-aware Systems

Abstract

In ubiquitous computing the environment constraints are often regarded as static and software applications are allowed to function in a mobile ecospace. However, in context-aware systems the environment attributes of software applications are dynamically changing. This dynamism of contexts must be accounted for in order to provide the true intended effect on the application of services. Consequently, context-aware software applications should perceive their context in a continuous manner and seamlessly adapt to it. This thesis investigates the process of constructing context-aware applications and identifies the main challenges in this domain. The two principal requirements are (1) formally defining what context is and expressing the enclosed semantics, (2) formally defining dynamic compositions of adaptations and triggering their responses to changes in the environment context. This thesis proposes a component-based architecture for a Context-aware Framework that would be used to bring awareness capabilities into applications. Two languages are formally designed. One is to formally express situations, leading to a context reasoner, and another is to formally express workflow, leading to timely triggering of reactions and enforcing policies. With these formalisms and a component design that can be formalized, the thesis work fulfills a formal approach to construct context-aware applications. A proof-ofconcept case study is implemented to examine the expressiveness of the framework design and test its implementation.