Reducing energy consumption within buildings has been an active area of research in the past decade;more recently, there has been an increased influx of activity, motivated by a variety of issues including legislative...
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Reducing energy consumption within buildings has been an active area of research in the past decade;more recently, there has been an increased influx of activity, motivated by a variety of issues including legislative, tax-related, as well as an increased awareness of energy-related issues. Energy usage both in commercial and residential buildings represents a significant portion of overall energy consumption;however, much of this may be categorized as waste, that is, energy usage that does not fulfil a definite purpose. In the past decade, the viability of Wireless sensor Network (WSN) technologies has been demonstrated, leading to increased possibilities for novel services for building energy management. This development has resulted in numerous approaches being proposed for harnessing WSNs for energy management and conservation. This article surveys the state-of-the-art in building energy management systems. A generic architecture is proposed after which a detailed taxonomy of existing documented systems is presented. Gaps in the literature are highlighted and directions for future research identified.
The ability to efficiently aggregate information - for example compute the average temperature - in large networks is crucial for the successful employment of sensor networks. This article addresses the problem of des...
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The ability to efficiently aggregate information - for example compute the average temperature - in large networks is crucial for the successful employment of sensor networks. This article addresses the problem of designing truly scalable protocols for computing aggregates in the presence of faults, protocols that can enable million node sensor networks to work efficiently. More precisely, we make four distinct contributions. First, we introduce a simple fault model and analyze the behavior of two existing protocols under the fault model: tree aggregation and gossip aggregation. Second, since the behavior of the two protocols depends on the size of the network and probability of failure, we introduce a hybrid approach that can leverage the strengths of the two protocols and minimize the weaknesses;the new protocol is analyzed under the same fault model. Third, we propose methodology for determining the optimal mix between the two basic protocols;the methodology consists in formulating an optimization problem, using models of the protocol behavior, and solving it. Fourth, we perform extensive experiments to evaluate the performance of the hybrid protocol and show that it usually performs better, sometimes orders of magnitude better, than both the tree and gossip aggregation.
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