Energy Efficient Data Collection in Hierarchical Wireless Sensor Networks

The majority of the energy consumption by the sensors is the energy requirement for data transmission in Wireless Sensor Networks （WSNs）. Therefore, introducing mobile collectors to collect data instead of nmlti-hop data relay is essential. However, for rmny proposed data gathering ap-proaches, long data deNNy is the train problenm. Hence, the problem of how to decrease the energy consumption and the data deNNy needs to be solved. In this paper, a low deNNy data collection mechanism using multiple mobile collectors is pro- posed. First, a self-organization clustering algorithm is designed. Second, sensor nodes are organized into three-level clusters. Then a collection strategy based on the hierarchical structure is proposed, which includes two rules to dispatch mobile collec- tors rationally. Simulation results show that the proposed mechanism is superior to other existing approaches in terms of the reduction in energy ex-penditure and the decrease in data deNNy.

Dynamic data packing towards the optimization of QoC and QoS in networked control systems

A class of networked control systems is investigated whose communication network is shared with other applications. The design objective for such a system setting is not only the optimization of the control performance but also the efficient utilization of the communication resources. We observe that at a large time scale the data packet delay in the communication network is roughly varying piecewise constant, which is typically true for data networks like the Internet. Based on this observation, a dynamic data packing scheme is proposed within the recently developed packet-based control framework for networked control systems. As expected this proposed approach achieves a fine balance between the control performance and the communication utilization: the similar control performance can be obtained at dramatically reduced cost of the communication resources. Simulations illustrate the effectiveness of the proposed approach.

A necessary and sufficient stability criterion for networked predictive control systems.

Stability of a networked predictive control system subject to network-induced delay and data dropout is investigated in this study. By modeling the closed-loop system as a switched system with an upper-triangular structure, a necessary and sufficient stability criterion is developed. From the criterion, it also can be seen that separation principle holds for networked predictive control systems. A numerical example is provided to confirm the validity and effectiveness of the obtained results.