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Sensor networks are widely used in many applications for collecting information from the physical environment. In these applications, it is usually necessary to track the relationships between sensor data readings within a time window to detect events of interest. However, it is difficult to detect such events by using the common aggregate or selection(More)
The middleware for a cyber-physical system is crucial as it tightly integrates computation with physical processes to achieve better reliability, distributed coordination, higher precision and efficiency, and better autonomous control. In this work, we design and develop the cyber-physical middleware framework for a large-scale water distribution system(More)
In this paper, we study the problem of processing multiple queries in a wireless sensor network. We focus on multi-query optimization at the base station level to minimize the number of radio messages in the sensor network. We adopt a cost-based approach, and develop a cost model to study the benefit of exploiting common subexpressions in queries. We also(More)
When there are multiple queries posed to the resource-constrained wireless sensor network, it is critical to process them efficiently. In this paper, we propose a Two-Tier Multiple Query Optimization (TTMQO) scheme. The first tier, called base station optimization, adopts a cost-based approach to rewrite a set of queries into an optimized set that shares(More)
I n recent years, rapid advances in high-performance microprocessor design technology have made it possible to build large-scale multiprocessors with a theoretically very high peak computational performance. Unfortunately, there is no corresponding improvement in memory speed and communication bandwidth. In fact, the gap between processor speed and memory(More)
—Coverage is an important performance metric for many applications such as surveillance in Wireless Sensor Networks (WSNs). Coverage control is used to select as few active nodes as possible from all deployed sensor nodes such that sufficient coverage of the monitored area can be guaranteed, while reducing the energy consumption of each individual sensor(More)