Context-aware applications monitor changes in their environment and switch their behaviour in order to continue satisfying requirements. Specifying monitoring and switching in such applications can be difficult due to their dependence on varying environmental properties. Two problems require analysis: the monitoring of environmental properties to assess their impact on continual requirements satisfaction, and the selection of appropriate behaviours that ensure requirements satisfaction. To address these problems, we provide concepts for refining contextual properties which we then use to formulate two theorems for monitoring and switching. These enable us to formally analyse the impact of context on monitoring and switching problems. We have instantiated our general approach by encoding monitoring and switching problems into propositional logic constraints, which we analyse automatically using a standard SAT solver. The approach is applied to an industrial case study to assess its efficacy.
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