In this paper, the closed loop transmit diversity technology for the Wideband Code Division Multiple Access(WCDMA) systems is investigated in a multipath Rayleigh fading channel. The RAKE receiver model and the weighi...In this paper, the closed loop transmit diversity technology for the Wideband Code Division Multiple Access(WCDMA) systems is investigated in a multipath Rayleigh fading channel. The RAKE receiver model and the weighing vector algorithm are presented. The performance is theoretically analyzed in terms of the average maximal Signal-to-Noise Ratio(SNR) gain available over the Space-Time block coding based Transmit Diversity(STTD) technology. Theoretic analysis and simulation results show that the closed loop transmit diversity can provide a 3dB performance gain over the open loop scheme in a single path fading channel, while the performance gain decreases dramatically with the increasing inherent multipath diversity of the wireless channel.展开更多
Suppression of noises is studied for the open-loop-closed-loop （OPCL） coupling systems between the driver and response systems. In OPCL coupling systems, the error signal of noise is found to be suppressed and shows...Suppression of noises is studied for the open-loop-closed-loop （OPCL） coupling systems between the driver and response systems. In OPCL coupling systems, the error signal of noise is found to be suppressed and shows bounds. The error signal can be decreased exponentially by enlarging the absolute value of the eigenvalues＇ real part of the Hurwitz matrix. A method is provided to reduce the error signal sufficiently and achieve complete synchronization （US） effectively for the OPCL coupling systems under noises. Based on this method, three numerical examples are reported in this paper,展开更多
Closed-loop identification is important and necessary to various model-based advanced process control strategies, whose performance depends greatly on the informative property of the data set. Switching control is an ...Closed-loop identification is important and necessary to various model-based advanced process control strategies, whose performance depends greatly on the informative property of the data set. Switching control is an important method in process control. Therefore, this paper studies the informative property of a data set in a single-input single-output (SISO) closed-loop system with a switching controller. It is proved that this data set is informative if the controller switches among at least two modes (i.e., feedback laws). Our result does not require any assumption on the way of switch and removes the constraints on the switching manner required in some classical literature. Finally, simulation case studies based on a continuous stirred-tank reactor (CSTR) process are given to validate the results.展开更多
This paper proposes a recursive algorithm estimating coefficients of the linear stochastic control system(ARX system) driven by a martingale difference sequence, while adaptively stabilizing the system without introdu...This paper proposes a recursive algorithm estimating coefficients of the linear stochastic control system(ARX system) driven by a martingale difference sequence, while adaptively stabilizing the system without introducing external excitation signal. The system is allowed to be unstable and of nonminimum-phase. The estimates derived for the coefficients of both closed-loop and open-loop systems are strongly consistent.展开更多
In this paper,we study lag synchronization between two coupled networks and apply two types of control schemes,including the open-plus-closed-loop(OPCL) and adaptive controls.We then design the corresponding control a...In this paper,we study lag synchronization between two coupled networks and apply two types of control schemes,including the open-plus-closed-loop(OPCL) and adaptive controls.We then design the corresponding control algorithms according to the OPCL and adaptive feedback schemes.With the designed controllers,we obtain two theorems on the lag synchronization based on Lyapunov stability theory and Barbalat's lemma.Finally we provide numerical examples to show the effectiveness of the obtained controllers and see that the adaptive control is stronger than the OPCL control when realizing the lag synchronization between two coupled networks with different coupling structures.展开更多
In this article,we review the recent progress in active control of a turbulent boundary layer for skin-friction drag reduction.Near-wall coherent structures,which are closely associated with large skin-friction drag a...In this article,we review the recent progress in active control of a turbulent boundary layer for skin-friction drag reduction.Near-wall coherent structures,which are closely associated with large skin-friction drag and are thus often the target to be manipulated,are discussed briefly,providing a rationale of various control strategies.Open-and closed-loop controls are extensively reviewed,largely focusing on techniques and drag-reduction mechanisms.Finally,some concluding remarks are given.展开更多
基金Supported by the National Natural Science Foundation of China (No. 60496311)
文摘In this paper, the closed loop transmit diversity technology for the Wideband Code Division Multiple Access(WCDMA) systems is investigated in a multipath Rayleigh fading channel. The RAKE receiver model and the weighing vector algorithm are presented. The performance is theoretically analyzed in terms of the average maximal Signal-to-Noise Ratio(SNR) gain available over the Space-Time block coding based Transmit Diversity(STTD) technology. Theoretic analysis and simulation results show that the closed loop transmit diversity can provide a 3dB performance gain over the open loop scheme in a single path fading channel, while the performance gain decreases dramatically with the increasing inherent multipath diversity of the wireless channel.
文摘Suppression of noises is studied for the open-loop-closed-loop （OPCL） coupling systems between the driver and response systems. In OPCL coupling systems, the error signal of noise is found to be suppressed and shows bounds. The error signal can be decreased exponentially by enlarging the absolute value of the eigenvalues＇ real part of the Hurwitz matrix. A method is provided to reduce the error signal sufficiently and achieve complete synchronization （US） effectively for the OPCL coupling systems under noises. Based on this method, three numerical examples are reported in this paper,
基金Supported by the National Basic Research Program of China (2010CB731800)the National Natural Science Foundation of China (60974059, 60736026, 61021063, 60904044, 61290324)Tsinghua National Laboratory for Information Science and Technology (TNList) Cross-discipline Foundation
文摘Closed-loop identification is important and necessary to various model-based advanced process control strategies, whose performance depends greatly on the informative property of the data set. Switching control is an important method in process control. Therefore, this paper studies the informative property of a data set in a single-input single-output (SISO) closed-loop system with a switching controller. It is proved that this data set is informative if the controller switches among at least two modes (i.e., feedback laws). Our result does not require any assumption on the way of switch and removes the constraints on the switching manner required in some classical literature. Finally, simulation case studies based on a continuous stirred-tank reactor (CSTR) process are given to validate the results.
基金This research is supportedby the National Natural Science Foundation of China and the National Key Project of China.
文摘This paper proposes a recursive algorithm estimating coefficients of the linear stochastic control system(ARX system) driven by a martingale difference sequence, while adaptively stabilizing the system without introducing external excitation signal. The system is allowed to be unstable and of nonminimum-phase. The estimates derived for the coefficients of both closed-loop and open-loop systems are strongly consistent.
基金Supported by the National Natural Science Foundation of China under Grant No.61304173Foundation of Liaoning Educational Committee(No.13-1069)and Hangzhou Polytechnic(No.KZYZ-2009-2)
文摘In this paper,we study lag synchronization between two coupled networks and apply two types of control schemes,including the open-plus-closed-loop(OPCL) and adaptive controls.We then design the corresponding control algorithms according to the OPCL and adaptive feedback schemes.With the designed controllers,we obtain two theorems on the lag synchronization based on Lyapunov stability theory and Barbalat's lemma.Finally we provide numerical examples to show the effectiveness of the obtained controllers and see that the adaptive control is stronger than the OPCL control when realizing the lag synchronization between two coupled networks with different coupling structures.
基金supported by the Research Grants Council of HKSAR (Grant No. PolyU 5350/10E)
文摘In this article,we review the recent progress in active control of a turbulent boundary layer for skin-friction drag reduction.Near-wall coherent structures,which are closely associated with large skin-friction drag and are thus often the target to be manipulated,are discussed briefly,providing a rationale of various control strategies.Open-and closed-loop controls are extensively reviewed,largely focusing on techniques and drag-reduction mechanisms.Finally,some concluding remarks are given.
