A smart home is a house that is responsive to its inhabitants and their actions by being aware of their context. Potential applications for smart homes address economic and comfort aspects of living, or could provide unobtrusive support for the elderly or disabled to promote independent living. The basic building blocks of such a smart home is a computing system consisting of distributed sensors and actuators. Programming and maintaining such an infrastructure is challenging because suitable programming abstractions are currently missing. In this paper we introduce the notion of programmable space that lets the application developer perceive the smart home as an integrated runtime environment. This approach is implemented in a system called RuleCaster. Applications are developed in a high-level rulebased language. Our approach shows a notable simplification of application development and maintenance. To verify the utility of RuleCaster we use a scenario-based evaluation method.

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Developing applications for smart spaces is a challenging task. Most programming systems narrowly focus on the embedded computer infrastructure and neglect the spatial aspect of this fusion between a physical and a virtual environment. Hence, application logic is not implemented for the smart space but for the embedded network, which is only one aspect of the system. Our programming system supports an abstract model of a smart space. A high-level language is used to implement the application logic for this model. In this paper we show how a compiler translates code written for this abstract model into a distributed application that can be executed by a computer infrastructure. The compiler allows for a clear separation between the application code and its execution in a concrete network. This simplifies the development and maintenance of an application because the application programmer can focus on the actual application logic for the smart space instead of issues related to a concrete network.

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Sensor networks are one important building block towards the realisation of context-aware applications. Suitable communication protocols and middleware solutions are necessary to facilitate the development of sensor network applications. Additionally, the vast number of nodes in sensor networks necessitates a new programming model for application developers. Commonly used programming abstractions force the programmer to express the global behaviour of a network in terms of local actions taken at individual nodes. We argue that global programming abstractions are needed to express global behaviour of a network. We present RuleCaster, a novel state-based programming framework for sensor network applications. RuleCaster provides a high-level language for application definition, a compiler that splits the high-level specification into individual tasks and assigns them to the nodes, and a service-based middleware that provides the interface for collaborative execution of these tasks.@en