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1.
In this paper, the issues of finite-time extended dissipative analysis and non-fragile control are investigated for a class of uncertain discrete time switched linear systems. Based on average dwell-time approach, sufficient conditions for the finite-time boundedness and finite-time extended dissipative performance of the considered systems are proposed by solving some linear matrix inequalities, where using the concept of extended dissipative, we can solve the H, L2?L, Passivity and (Q, S, R)-dissipativity performance in a unified framework. Furthermore, two form of non-fragile state feedback controllers are designed to guarantee that the closed-loop systems satisfy the finite-time extended dissipative performance. Finally, simulation example is given to show the efficiency of the proposed methods.  相似文献   

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In the work, the finite-time non-fragile l2?l control problem for jumping stochastic systems with input constraints is addressed. An event-triggered mechanism is introduced to reduce the burden of the data communications. Our goal is to design a controller which makes sure that the underlying closed-loop system could be stochastically finite-time bounded at a specified level of l2?l performance. By using the finite-time analysis theory, some sufficient conditions are proposed for the existence of such a desired controller. The availability of the developed method is finally explained by an illustrated example.  相似文献   

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One of the important image processing tasks is to effectively reduce a noise from a digital image while keeping its features intact. In this paper, a new noise removal method for color images corrupted by the mixture of the impulsive and Gaussian noises is proposed. In the proposed method, firstly, a tentative output image, in which the noise is removed almost perfectly, is obtained by using the iterative robust switching vector median-based vector ε-filter, which is realized by hybridizing the robust switching vector median filter and the vector ε-filter and is newly proposed here. Then the residual components between the input and the tentative output images are calculated, and image components constituting edges, corner and other image details are extracted from the residual components by using the correlation characteristic in RGB components. Consequently, a final output is obtained by adding the extracted image components into the tentative output image. The effectiveness and the validity of the proposed method are verified by some experiments using the natural color images.  相似文献   

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This paper is concerned with the problem of designing an observer-based quantized feedback controller for the continuous-time switched linear systems, in which the transmission of switching signal is subject to unbounded delays and packet loss. To deal with the unbounded switching delays, we design a constant d¯ to determine that the switching signal received by controller is ignored or not. Based on that, if the signal is timestamped, the controller’s mode is uniquely determined. Moreover, we adjust the quantizer parameters in real time depending on the actual transmission situations to ensure the unsaturation of quantizer and thus the boundness of quantization error. Within this setup, we derive a maximum allowable packet loss rate ensuring the mean square stability of the closed-loop switched systems. An illustrative example is given to show the usefulness of the proposed framework for the quantized stabilization of some classes of switched systems.  相似文献   

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This paper is concerned with non-fragile H control problems for a class of continuous-time nonlinear systems with unknown nonlinearity and quantized inputs and outputs. The construction of both static output feedback (SOF) and observer-based output feedback (OBOF) control laws in the presence of additive interval-bounded controller coefficient variations can be divided into two parts, linear and nonlinear parts. The linear part plays a role in achieving the H performance, while the nonlinear part is used to reduce the quantization effect. However, it should be pointed out that the effect of input and output quantization can be eliminated fully for SOF case by requiring knowledge of all signs of the states, but only the effect of input quantization can be eliminated for OBOF case. It is worth mentioning that three novel alternative methods with strict linear matrix inequality (LMI) conditions are proposed to design both SOF and OBOF controllers. In particular, these three new methods do not introduce any other auxiliary constraints as many existing results do where a matrix equality constraint between system matrix and Lyapunov matrix is often inserted. Finally, the effectiveness and advantages of the proposed control methods are demonstrated by a numerical example.  相似文献   

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This paper is concerned with finite-time HH control problem for a class of switched linear systems by using a mode-dependent average dwell time (MDADT) method. The switching signal used in this paper is more general than the average dwell time (ADT), in which each mode has its own ADT. By combining the MDADT and Multiple Lyapunov Functions (MLFs) technologies, some sufficient conditions, which can guarantee that the corresponding closed-loop system is finite-time bounded with a prescribed HH performance, are derived for the switched systems. Moreover, a set of mode-dependent dynamic state feedback controllers are designed. Finally, two examples are given to verify the validity of the proposed approaches.  相似文献   

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As the filter which can effectively remove the small amplitude noises on digital images, the ε-filter has been proposed. In order to effectively use this filter, a smoothing parameter ε-filter should be appropriately estimated before applying it. To address this problem, the authors proposed the parameter estimation method based on Hellinger distance (HD). In the method, HD between a residual signal and assumed noise distribution was evaluated, and a parameter ε of the ε-filter was estimated by finding the value giving minimum distance. However, the enough discussion on use of HD has not been made.In this paper, it is attempted to utilize not only the HD, but also various distribution distances in the parameter estimation, and their performances and characteristics are compared and analyzed experimentally. Furthermore, the parameter estimation method is extended to be applicable for the vector ε-filter for the color images. Consequently, through the experiments, it is shown that L1-norm or maximum norm is appropriate as the distribution distance used in the parameter estimation methods from the view points of the simplicity of the calculation and MSE performance in the filtering.  相似文献   

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This paper presents an optimal solution to asteroid soft landing problem, on the base of θ?D control technique and disturbance rejection mechanism. The control objective is to drive a probe to reach the surface of an asteroid with a desirable line-of-sight angle and zero velocity, eliminating the influence of external disturbance. Firstly, elementary θ?D technique is applied in the absence of disturbance to tackle the nonlinear optimal control problem. Secondly, the disturbance is estimated in the fast-estimation framework with explicitly bounded estimation error. Afterwards, an integrated control protocol is presented in a feed-forward structure by the aid of an additional variable-structure term to ensure stability under time-varying disturbance. Simulation results of the proposed approach compared with the results of elementary θ?D method and robust θ?D method are presented at the end of this paper, demonstrating the effectiveness of the proposed control protocol.  相似文献   

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Given any finite family of real d-by-d nonsingular matrices {S1,,Sl}, by extending the well-known Li–Yorke chaos of a deterministic nonlinear dynamical system to a discrete-time linear inclusion or hybrid or switched system:
xn{Skxn?1;1kl},x0Rdandn1,
we study the chaotic dynamics of the state trajectory (xn(x0, σ))n ≥ 1 with initial state x0Rd, governed by a switching law σ:N{1,,l}. Two sufficient conditions are given so that for a “large” set of switching laws σ, there exhibits the scrambled dynamics as follows: for all x0,y0Rd,x0y0,
lim infn+xn(x0,σ)?xn(y0,σ)=0andlim supn+xn(x0,σ)?xn(y0,σ)=.
This implies that there coexist positive, zero and negative Lyapunov exponents and that the trajectories (xn(x0, σ))n ≥ 1 are extremely sensitive to the initial states x0Rd. We also show that a periodically stable linear inclusion system, which may be product unbounded, does not exhibit any such chaotic behavior. An explicit simple example shows the discontinuity of Lyapunov exponents with respect to the switching laws.  相似文献   

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This paper discusses the problem of synchronization for delayed neural networks using sampled-data control. We introduce a new Lyapunov functional, called complete sampling-interval-dependent discontinuous Lyapunov functional, which can adequately capture sampling information on both intervals from r(t?τ¯) to r(tk?τ¯) and from r(t?τ¯) to r(tk+1?τ¯). Based on this Lyapunov functional and an improved integral inequality, less conservative conditions are derived to ensure the stability of the synchronization error system, leading to the fact that the drive neural network is synchronized with the response neural network. The desired sampled-data controller is designed in terms of solutions to linear matrix inequalities. A numerical example is provided to demonstrate that the proposed approaches are effective and superior to some existing ones in the literature.  相似文献   

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In this paper, by applying the real representations of complex matrices, the particular structure of the real representations and the Moore–Penrose generalized inverse, we obtain the explicit expression of the minimal norm least squares Hermitian solution of the complex matrix equation AXB+CXD=E. And we also derive the minimal norm least squares Hermitian solution of the complex matrix equation AXB=E. Our proposed formulas only involve real matrices, and therefore are more effective and portable than those reported in Yuan and Liao (2014). The corresponding algorithms only perform real arithmetic which also consider the particular structure of the real representations of complex matrices. Two numerical examples are provided to demonstrate the effectiveness of our algorithms.  相似文献   

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