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Thesis

Estimation and control over networks using event-based transmission methods

Authors: Nguyễn, Vĩnh Hảo.; Advisor: Lee, Hong-Hee; Suh, Young Soo (2008)

The thesis is concerned with the state estimation and control problem over the network in which an event-based sampling scheme at sensor nodes is proposed. If the network speed is high and the traffic is sparse, the traditional periodic sampling approach has many merits. But when the network bandwidth is limited due to executing tasks of several nodes, time delay becomes large and randomly varying. Therefore, to avoid these problems the sensor data transmission rate should be reduced. In the event-driven sampling scheme, sensor data are transmitted to the estimator node only if the difference between the current sensor value and the last transmitted one is greater than a given threshold. The research has shown that the event-based sampling scheme is more efficient than the periodic ...

Thesis

Linear phase filter bank design by convex programming

Authors: Hà, Hoàng Kha. (2008)

Digital filter banks have found in a wide variety of applications in data compression, digital communications, and adaptive signal processing. The common objectives of the filter bank design consist of frequency selectivity of the individual filters and perfect reconstruction of the filter banks. The design problems of filter banks are intrinsically challenging because their natural formulations are nonconvex constrained optimization problems. Therefore, there is a strong motivation to cast the design problems into convex optimization problems whose globally optimal solutions can be efficiently obtained. The main contributions of this dissertation are to exploit the convex optimization algorithms to design several classes of the filter banks. First, the two-channel orthogonal sym...