Subspace-based system identification methods have been developed over the last two decades. The available methods are algebraic in nature as they are not based on a suitable identification criterion minimization. The ...
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Subspace-based system identification methods have been developed over the last two decades. The available methods are algebraic in nature as they are not based on a suitable identification criterion minimization. The aim of this paper is to investigate the subspace identification methods in the spirit of the well known prediction error methods and output error methods.
By applying the auxiliary variational principle technique, the existence of solutions for a new class of generalized mixed implicit quasi-variational-like inequalities and the convergence criteria of a new iterative a...
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By applying the auxiliary variational principle technique, the existence of solutions for a new class of generalized mixed implicit quasi-variational-like inequalities and the convergence criteria of a new iterative algorithm to compute approximate solutions are proved in Hilbert spaces. The obtained result is a improvement over and generalization of the main theorem proposed by Ding.
An iterative adaptive pole placement algorithm is presented. The stability and the convergence of the algorithmare respectively established. Since one-step iterative formulation in computing controller's parameter...
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An iterative adaptive pole placement algorithm is presented. The stability and the convergence of the algorithmare respectively established. Since one-step iterative formulation in computing controller's parameters is used, the on-line computation cost is greatly reduced with respected to the traditional algorithm. The algorithm with the feed-forward can follow arbitrarily bounded output. The algorithm is also extended to multivariate case. Simulation examples show the efficiency and robustness of the algorithm.
In this paper, a new image reconstruction method based on genetic algorithm (GA) for electrical capacitance tomography (ECT) is presented. Using the initial result from the linear back-projection algorithm widely used...
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In this paper, a new image reconstruction method based on genetic algorithm (GA) for electrical capacitance tomography (ECT) is presented. Using the initial result from the linear back-projection algorithm widely used for ECTimage reconstruction, the GA based method optimizes the threshold, the maximal and the minimal gray value for the image. And the Tikhonov regularization is adopted as the fitness function, which avoids optimizing the gray value for pixel one by one and decreases significantly the dimension of searching space. Then the optimized reconstruction image can be obtained by these three parameters and LBP initial result. Numerical results show that high efficiency, good image quality and applicability can be achieved by using the GA based method. Compared with the Projected Landweber method, the GA based method can reconstruct better image by taking the shorter computation time.
It is only the relative phase distribution between the tested object and reference plane that is attained after phase demodulation and phase unwrapping in profilometry. However, the objective of 3D shape measurement i...
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It is only the relative phase distribution between the tested object and reference plane that is attained after phase demodulation and phase unwrapping in profilometry. However, the objective of 3D shape measurement is to obtain the object's height distribution. The nonlinear mapping relationship of both phase and height is analysed and deduced in a general experimental setup. The calibration scheme is designed. When the reference plane is shifted, its corresponding phases have been measured. According to the shifted distance and the phase increment, the mapping relationship between phase difference and depth of the object can determined by the least square interactive method. Finally, a practical experimental system is calibrated and compared with Hung's method. The experimental results and theoretical analysis show that the new method is characterized by the high accuracy, easy to handle, lower the complexity of calibration.
This paper proposes a relaxation algorithm for an inverse filter that is adaptive to environmental change in a multichannel sound reproduction system. For a conventional multichannel sound reproduction system, a desig...
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This paper proposes a relaxation algorithm for an inverse filter that is adaptive to environmental change in a multichannel sound reproduction system. For a conventional multichannel sound reproduction system, a design method has been proposed for an inverse filter by means of the Moore-Penrose-type generalized inverse matrix. However, in the inverse filter in the conventional method, background noise and line noise may be enhanced when the room transfer characteristics vary. In order to resolve this problem, an adaptive relaxation method based on the truncated singular value decomposition (TSVD) has been introduced. In the present paper, a microphone for monitoring the noise is placed at a location far from both ears of the listener. Relaxation of the inverse filter is carried out by using the reproduced sound observed by this microphone. From the results of computer simulation, it is found that the proposed method prevents amplification of the noise. Also, as a result of a subjective evaluation experiment on sound reproduction in a real acoustic environment, the sound quality was found to be improved significantly without damaging the sound localization of position. (C) 2004 Wiley Periodicals, Inc.
Coherent diffractive imaging using a coherent X-ray source promises to be a useful microscopic method for imaging noncrystalline objects at high spatial resolution. In this article a simple method to estimate the cohe...
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Coherent diffractive imaging using a coherent X-ray source promises to be a useful microscopic method for imaging noncrystalline objects at high spatial resolution. In this article a simple method to estimate the coherently scattered signal as a function of resolution is presented, and it is shown that the required X-ray flux or dose scales as the inverse third power of resolution for a specimen of constant volume and density. A simulated case study using the proposed energy-recovery linac source is also presented, which confirms the estimated flux requirement.
In this paper, we first introduce a new class of generalized accretive operators named H-accretive operators in Banach spaces. By studying the properties of H-accretive operators, we extend the concept of resolvent op...
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In this paper, we first introduce a new class of generalized accretive operators named H-accretive operators in Banach spaces. By studying the properties of H-accretive operators, we extend the concept of resolvent operators associated with the classical m-accretive operators to the new H-accretive operators. In terms of the new resolvent operator technique, we give the approximate solution for a class of variational inclusions involving H-accretive operators in Banach spaces. (C) 2004 Elsevier Ltd. All rights reserved.
This paper investigates the problem of energy-efficient transmission of data packets in a wireless network by jointly adapting to backlog and channel condition. Specifically, we consider minimum-energy scheduling prob...
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This paper investigates the problem of energy-efficient transmission of data packets in a wireless network by jointly adapting to backlog and channel condition. Specifically, we consider minimum-energy scheduling problems over multiple-access channels, broadcast channels, and channels with fading, when packets of all users need to be transmitted before a deadline T. Earlier work has considered a similar setup and demonstrated significant transmission energy saving by adapting to backlog for channels that are time invariant and when transmission is restricted to time-division. For concreteness, throughout the paper, rates and powers corresponding to optimal coding over discrete-time additive white Gaussian noise (AWGN) channels are assumed. The results, however, hold for more general channels and coding schemes where the total transmitted power is convex in the transmission rates. The offline scheduling problems for all the channels considered are shown to reduce to convex optimization problems with linear constraints. An iterative algorithm, referred to as FlowRight, that finds optimal offline schedules is presented. A heuristic online algorithm that we call look-ahead water-filling, which jointly adapts to both channel fading state and backlog is described. By the use of a small buffer which introduces an almost fixed delay, this algorithm achieves a considerable reduction in energy relative to water filling solely on channel states.
Dynamic analysis of structural systems requires a considerable amount of computing time. Because the dynamic behavior of a structure is dominated by lower modes, all of the eigenvalues of the system need not be calcul...
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Dynamic analysis of structural systems requires a considerable amount of computing time. Because the dynamic behavior of a structure is dominated by lower modes, all of the eigenvalues of the system need not be calculated. The previously proposed methods approximate the eigenvalues of a global system but they take great amount of computing time to construct a reduced system. An element-level energy estimation technique is proposed to construct a reduced finite element model. Through several examples, it is demonstrated that the proposed method effectively saves computational time and accurately predicts the eigenvalues of a global system.
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