Browsing by Author "Lin, CA"

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An algorithm for inverting rational matrices
(1996-01-31)
Lin, CA
;
Yang, CW
;
Hsieh, TF
;
交大名義發表
;
電控工程研究所
We propose an algorithm for computing the inverses of rational matrices and in particular the inverses of polynomial matrices. The algorithm is based on minimal state space realizations of proper rational matrices and the matrix inverse lemma and is implemented as a MATLAB function. Experiments show that the algorithm gives accurate results for typical rational matrices that arise in analysis and design of linear multivariable control systems. Illustrative examples are given.
Blind identification of MIMO channels with periodic modulation
(2005)
Lin, CA
;
Chen, YS
;
電控工程研究所
;
Institute of Electrical and Control Engineering
We propose a method for blind identification of MIMO FIR channels with periodic modulation. The method exploits linear relation between the covariance matrix of the received data and the "product matrices" of the channel. The proposed algorithm requires solving linear equations and computing eigenvalues and eigenvectors of a Hermitian matrix. We show that the identiflability condition depends on the modulating sequences alone and the method is robust with respect to channel order overestimation. A method for optimal selection of modulating sequences is proposed, which takes into account the effect of noise and the numerical error in estimating the covariance matrix of the received data. Simulations are used to demonstrate the performance of the proposed algorithm.
Blind identification with periodic modulation: A time-domain approach
(2002-11-01)
Lin, CA
;
Wu, JY
;
電控工程研究所
;
Institute of Electrical and Control Engineering
We propose a method for blind identification of finite impulse response (FIR) channels with periodic modulation. The time-domain formulation in terms of block signals is simple compared with existing frequency-domain formulations. It is shown that the linear equations relating the products of channel coefficients and the autocorrelation matrix of the received signal can be further arranged into decoupled groups. The arrangement reduces computations and improves accuracy of the solution; it also leads to very simple identiflability conditions and a very natural formulation of the optimal modulating sequence selection problem. The proposed optimal selection minimizes the effects of channel noise and error in autocorrelation matrix estimation; it results in a consistent channel estimate when the channel noise is white. Simulation results show, that the method yields good performance: It compares favorably with an existing subspace modulation-induced-cyclostationarity method, and it is robust with respect to channel order overestimation. The effect of modulation period and threshold of the modulating sequence are also discussed.
Block-decoupling linear multivariable systems: Necessary and sufficient conditions
(1998-02-01)
Lin, CA
;
Wu, CM
;
電控工程研究所
;
Institute of Electrical and Control Engineering
We study block decoupling of linear multivariable systems under unity-feedback configuration. We consider plants which have unstable pole-zero coincidences and give necessary and sufficient conditions for the existence of the block decoupling controllers. The conditions are particularly simple for plants with only simple unstable pole-zero coincidences. An illustrative example is given. (C) 1998 Elsevier Science Ltd. All rights reserved.
Control system design for a rapid thermal processing system
(2001-01-01)
Lin, CA
;
Jan, YK
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper proposes a control system design for a rapid thermal processing (RTP) system, which has four circular concentric lamp zones and four temperature sensors. The control system consists of a least square feedforward controller and an output feedback proportional plus integral (PI) controller. The goal is to maintain uniform temperature tracking for typical ramp-up and hold-steady profiles. A high-order nonlinear model describing the temperature dynamics of the rapid thermal processing (RTP) system is used for the feedforward controller design. A balanced reduced model, obtained from a linear model around a desired uniform steady-state temperature, is used for the design of the multiinput-multioutput (MIMO) PI controller. The PI controller gain matrices are designed using an LQR-based procedure. Tradeoff between robustness and performance of the system is discussed, Simulation results show the control system designed yields robust temperature tracking with good uniformity for a wide temperature range.
Decoupling precompensation and optimal decoupling
(2001-01-01)
Lin, CA
;
Wu, CM
;
電控工程研究所
;
Institute of Electrical and Control Engineering
We study decoupling control under a unity-feedback configuration for linear multivariable plants. We parametrize the set of all admissible decoupling precompensators. With the parametrization, it is shown that decoupling controller design is equivalent to a set of SISO controller designs. The parametrization is also used to establish a necessary and sufficient condition for the existence of a stable decoupling controller. Optimal decoupling controller design is proposed and the cost of decoupling is discussed.
Lamp configuration design for rapid thermal processing systems
(1998-02-01)
Jan, YK
;
Lin, CA
;
電控工程研究所
;
Institute of Electrical and Control Engineering
We study lamp configuration design for rapid thermal processing (RTP) systems, We consider a configuration consists of four concentric circular lamp zones, three of them above the wafer and one circumvallating the wafer, We propose a method to determine the geometric parameters, the width, height and radius, of the lamp zones so that the configuration designed has the capacity to achieve uniform temperature on the wafer, The method is based on a necessary and sufficient condition for uniform temperature tracking and analytic expressions of the view factors, A design example is given in which a least square open-loop control law yields good temperature uniformity.
Multi-input multi-output PI controller design
(2000)
Lin, CA
;
Gundes, AN
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The design of MIMO PI controller is formulated as an LQR problem. The weighting matrices of the quadratic performance index are chosen so that tuning can be done for each input-output channel and for tradeoff between transient response and robustness with respect to modeling error. The number of tuning parameters is the same as that of a decentralized PI controller. A design example is given to demonstrate the feasibility of the proposed approach.
Necessary and sufficient conditions for existence of block decoupling controllers
(1996)
Lin, CA
;
Wu, CM
;
交大名義發表
;
電控工程研究所
;
National Chiao Tung University
We study block decoupling of linear multivariable system under unity-feedback configuration. We give necessary and sufficient conditions for the existence of stabilizing block decoupling controllers. The conditions are simple and straightforward.
Necessary and sufficient conditions for existence of decoupling controllers
(1997-08-01)
Lin, CA
;
電控工程研究所
;
Institute of Electrical and Control Engineering
It is well known that if a linear time-invariant plant is free from coincidences of poles and zeros in the right half-plane, then it can be decoupled with internal stability under unity-feedback configuration, We consider plants for which such coincidences do occur and give necessary and sufficient conditions under which stabilizing decoupling controllers exist. The conditions derived, based on transfer matrices and residues, are simple and straightforward.
Necessary and sufficient conditions for existence of decoupling controllers
(1997-08-01)
Lin, CA
;
交大名義發表
;
電控工程研究所
;
National Chiao Tung University
;
Institute of Electrical and Control Engineering
It is well known that if a linear time-invariant plant is free from coincidences of poles and zeros in the right half-plane, then it can be decoupled with internal stability under unity-feedback configuration, We consider plants for which such coincidences do occur and give necessary and sufficient conditions under which stabilizing decoupling controllers exist. The conditions derived, based on transfer matrices and residues, are simple and straightforward.
Necessary and sufficient conditions for existence of decoupling controllers
(1995)
Lin, CA
;
電控工程研究所
;
Institute of Electrical and Control Engineering
Optimal approximate inverse of linear periodic filters
(2004-09-01)
Wu, JY
;
Lin, CA
;
電控工程研究所
;
電信工程研究所
;
Institute of Electrical and Control Engineering
We propose a method for constructing optimal causal approximate inverse for discrete-time single-input single-output (SISO) causal periodic filters in the presence of measurement noise. The analysis is based on block signals and multi-input multi-output (MIMO) time-invariant models for periodic filters. The objective function to be minimized is the asymptotic block mean square error. The optimization problem is formulated in terms of transfer matrices as an optimal model-matching problem with nonsquare model and plant. Based on an inner-outer factorization on the transpose of the plant rational matrix, it is shown that the problem can be further reduced to one with a lower dimensional square model and plant, which is then solved in the time-domain, and a closed-form solution is obtained. A lower bound on the objective function is given. It is shown that the lower bound can be asymptotically achieved as the order of the optimal transfer matrix increases. The proposed method is extended to MIMO periodic systems. Numerical examples are used to illustrate the performance of the proposed approximate inverse.
Optimal finite impulse response approximate inverse of linear periodic filters
(2006-04-01)
Wu, JY
;
Lin, CA
;
電控工程研究所
;
電信工程研究所
;
Institute of Electrical and Control Engineering
A method to construct an optimal finite impulse response (FIR) approximate inverse for discrete-time causal FIR periodic filters in the presence of measurement noise is proposed. The objective function to be minimised is the sum-of-mean-square errors over one period. On the basis of the matrix impulse response of the multi-input multi-output time-invariant representation of periodic filters, the optimisation problem is formulated as one that minimises the summed equation errors of a set of over-determined linear equations. It is shown that the problem is equivalent to a set of least-squares problems from which a simple, closed-form solution is obtained. Numerical examples are used to illustrate the performance of the proposed FIR approximate inverse.
Optimal FIR approximate inverse of linear periodic filters
(2004)
Wu, JY
;
Lin, CA
;
電控工程研究所
;
Institute of Electrical and Control Engineering
We propose a method for constructing FIR approximate inverse for discrete-time causal FIR periodic filters in the presence of measurement noise. The objective function to be minimized is the sum of the error variance over one period. The optimization problem is formulated based on the matrix impulse response of the multi-input multi-output (MIMO) time-invariant representation of periodic filter as one that minimizes the sum of equation errors of a set of over-determined linear equations. It is shown that the problem is equivalent to a set of least squares problems and a simple closed-form solution is obtained Numerical examples are used to illustrate the performance of the proposed FIR approximate inverse.
Recombination dynamics of luminescence in colloidal CdSe/ZrS quantum dots
(2005-09-01)
Lee, WZ
;
Shu, GW
;
Wang, JS
;
Shen, JL
;
Lin, CA
Recombination dynamics of photoluminescence (PL) in colloidal CdSe/ZnS quantum dots (QDs) were studied using time-resolved PL measurements. The PL intensity shows a biexponential decay at 9 K, consisting of a fast component (similar to 1 ns) and a slow component (similar to 6.3 ns). Based on the emission-energy and temperature dependence of carrier lifetimes, we suggest that the fast and slow PL decay of colloidal CdSe/ZnS QDs originates from recombination of the delocalized carriers in the internal core states and the localized carriers at the interface, respectively.
Rectangular meshes construction of the human urethra using 3-D GVF snakes
(2004)
Ching, YT
;
Lin, CY
;
Tan, KC
;
Lau, KL
;
Yang, CH
Accurate 3-D rectangular meshes construction of pipes is important and valuable for Engineering and Medicine to analyze the fluid mechanics. Hypertrophied prostate is suffered common by aged patient. Medicine trusts that the pathogenic reason can be interpreted using the statistics of analysis of fluid mechanics. We use serials of methods to construct the 3-D rectangular meshes of a patient urethra CT volumetric data given from medicine, and for mechanic engineering to gather statistics.
Second-order approximations for RLC trees
(2004-07-01)
Lin, CA
;
Wit, CH
;
電控工程研究所
;
Institute of Electrical and Control Engineering
We propose two-pole one-zero second-order approximations for transfer functions in resistance-inductance-capacitance trees. The approximation matches the first three moments of the original transfer function. Formulas for computing step-response parameters such as delay time, rise time, overshoot, etc., are given. Simulation results show that adding the zero improves accuracy of the approximation.