Context-awaxe computing refers to a computing paradigm in which the behavior of individual components is determined by the circumstances in which they find themselves to an extent that greatly exceeds the typical system/environment interaction pattern common to most modern computing. The environment has an exceedingly powerful impact on a particular application component either because the latter needs to adapt in response to changing external conditions or because it relies on resources whose availability is subject to continuous change. In this paper we seek to develop a systematic understanding of the quintessential nature of context-aware computing by constructing a formal model and notation for expressing context-aware computations. We start with the basic premise that, in its most extreme form, context should be made manifest in a manner that is highly local in appearance and decoupled in fact. Furthermore, we assume a notion of context that is relative to the needs of each individual component, and we expect context-awareness to be maintained in a totally transparent manner with minimal programming effort. We construct the model from first principles, seek to root our decisions in these formative assumptions, and make every effort to preserve minimality of concepts and elegance of notation.
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