Distributed Spatial Analysis in Wireless Sensor Networks

Environmental monitoring is an important application area for wireless sensor networks (WSNs). An important problem for environmental WSNs is the characterization of the dynamic behaviour of transient physical phenomena over space. In the case of mote-level WSNs, a solution that is computed inside the WSN is essential for energy efficiency. In this context, the main contributions of this paper to the literature on in network processing in WSNs are threefold. The paper further develops an algebraic framework with which one can express and evaluate complex topological relationships over geometrical representations of permanent features (e.g., buildings, or geographical features such as lakes and rivers) and of transient phenomena (e.g., areas of mist over a cultivated field). The paper then describes distributed implementations of spatial-algebraic operations over the regions represented by that framework, thereby enabling identification of topological relationships between regions. Finally, the paper presents experimental evidence that the techniques described lead to efficient runtime behaviour. Taken together, these contributions constitute a further step towards enabling the high-level specification of expressive spatial analyses for efficient execution inside a WSN.