• 전자공학회논문지CI
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• 제41권3호
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• pp.79-90
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• 2004

본 논문에서는 퍼지 피드백 선형화 제어 시스템에 대한 체계적인 강인 안정성 해석과 제어기 설계방법을 제안한다. 제어 대상인 비선형 시스템을 모델링 하는데 있어서 Takagi-Sugeno 퍼지 모델 기법을 이용하고, 이때 발생할 수 있는 모델 불확실성과 외란을 고려한다. 모델링을 통해서 얻어진 폐루프 시스템에 대한 안정성 판별은 Diagonal Norm based Linear Differential Inclusions 으로의 구조 변환을 이용하여 강인 안정성 해석을 하였으며, 퍼지 피드백 선형화 제어 시스템을 안정화시키는 제어기의 이득을 얻기 위하여 LMI 최적화 계산법을 기반으로 한 수치 해석법을 제시하였다. 제안된 방법의 효과를 확인하기 위해서 강인 안정성 해석 및 제어 설계에 대한 모의실험을 수행한다.

• 응용통계연구
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• 제10권1호
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• pp.177-187
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• 1997

고정효과가 하나인 이원혼합모형에서의 고정효과 유의성검정에 대한 검정력 분석을 고려한다. 고정효과 수준간의 차이를 검정하는데 사용되는 일반화 최소제곱 F 통계량을 헨더슨의 방법 III, 사전추측값이 1인 MINQUE 추정량, 최우추정법, 제한적 최우 추정법을 이용하여 구하고 이 검정 통계량들의 검정력을 모의실험을 통하여 알아본다. 모의실험의 결과는 결론적으로 검정력의 측면에서 살펴본 효율성은 4가지 추정량 모두 대체적으로 비슷한 것으로 판명되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.529-531
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• 2005

A block-based fast motion estimation algorithm is proposed in this paper to perform motion estimation based on the efficiently reduced search ranges in MPEG-4(ERS). This algorithm divides the search areas into several small search areas and the candidate small search area that has the lowest average of sum norm difference between current macroblock and candidate macroblock is chosen to perform block motion estimation using the Nobel Successive Elimination Algorithm (NSEA). Experimental results of the proposed algorithm show that the averaging PSNR improvement is better maximum 0.125 dB than other tested algorithms and bit saving effect is maximum 20kbps for some tested sequences in low-bit rate circumstance.

• IEIE Transactions on Smart Processing and Computing
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• 제2권5호
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• pp.277-281
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• 2013

Modern speaker verification systems based on support vector machines (SVMs) use Gaussian mixture model (GMM) supervectors as their input feature vectors, and the maximum a posteriori (MAP) adaptation is a conventional method for generating speaker-dependent GMMs by adapting a universal background model (UBM). MAP adaptation requires the appropriate amount of input utterance due to the number of model parameters to be estimated. On the other hand, with limited utterances, unreliable MAP adaptation can be performed, which causes adaptation noise even though the Bayesian priors used in the MAP adaptation smooth the movements between the UBM and speaker dependent GMMs. This paper proposes a sparse MAP adaptation method, which is known to perform well in the automatic speech recognition area. By introducing sparse MAP adaptation to the GMM-SVM-based speaker verification system, the adaptation noise can be mitigated effectively. The proposed method utilizes the L0 norm as a regularizer to induce sparsity. The experimental results on the TIMIT database showed that the sparse MAP-based GMM-SVM speaker verification system yields a 42.6% relative reduction in the equal error rate with few additional computations.

• 한국지능시스템학회논문지
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• 제13권5호
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• pp.582-589
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• 2003

본 논문에서는 퍼지 피드백 선형화 제어 시스템에 대한 강인 안정성 해석과 제어기 설계에 대해서 말하고 있다. 제어 대상인 비선형 시스템을 모델링 하는데 있어서 Takagi-Sugeno (TS) 퍼지 모델 기법을 이용하였고, 이때 발생할 수 있는 모델 불화실성과 외란에 대해 그것의 최대 최소 범위를 안다고 가정하였다. 모델링을 통해서 얻어진 폐구간 시스템에 대한 안정성 판별은 Diagonal Norm based Linear Differential Inclusions (DNLDI) 구조를 이용하여 $L_2$ 강인 안정성 해석을 하였다. 또한, 퍼지 피드백 선형화 제어 시스템을 안정화 시키는 최대 이득을 얻기 위하여 LMI 최적화 계산법을 기반으로한 수치 해석법을 제시하였다. 제안된 방법의 효과를 확인하기 위해서 강인 안정성 해석 및 제어 설계에 대한 간단한 모의실험을 하였다.

• International Journal of Control, Automation, and Systems
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• 제3권2호
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• pp.225-235
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• 2005

This paper presents the robust stability analysis and design methodology of the fuzzy feedback linearization control systems. Uncertainty and disturbances with known bounds are assumed to be included in the Takagi-Sugeno (TS) fuzzy models representing the nonlinear plants. $L_2$ robust stability of the closed system is analyzed by casting the systems into the diagonal norm bounded linear differential inclusions (DNLDI) formulation. Based on the linear matrix inequality (LMI) optimization programming, a numerical method for finding the maximum stable ranges of the fuzzy feedback linearization control gains is also proposed. To verify the effectiveness of the proposed scheme, the robust stability analysis and control design examples are given.

• 전자공학회논문지B
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• 제33B권6호
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• pp.12-22
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• 1996

A numerous designs of PI controllers have been suggested to solve out trade-off between tracing and regulating problems. We constructed the PI controller system with two-degree-of-freedom that is more analytic and a better approach to a practical one. In the conventional H$_{2}$ design of optimal PI controllers, the cost function includes only the plant output terms due to the divergent problems. Since the platn input temr is not considered in PI controller design, occasionally, the plant input thends to be either very large or saturated. To solve the prior mentioned problems, we employed a mixed $H_2/H_{\infty}$ method that combines the H$_{2}$ design method to decide optimal parameters of PI controller and the $H_2/H_{\infty}$ design method to minimize the maximum amplitude of plant input. The calculation time of the H$_{infty}$ norm was considerably reduced by the simple scalar function obtained by the wiener-hopf factorization of non-scalar functions.

• 전자공학회논문지B
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• 제31B권1호
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• pp.64-71
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• 1994

In this paper, we propose orthogonal integer transform(OIT) with general form. Considering the orthogonality and magnitude value order of the DCT Matrix whose performance is found to be close to that of the KLT, known to be optimal. The proposed OIT matrix is composed of values minimizing Hibert-Schmidt norm among integer values which satisfy the condition of orthogonality and the relative magnitudes of the DCT matrix. Comparing the OIT with the DCT, CMT, and ICT in error characteristics, transform efficiency, and maximum reducible bit, it is shown that the performance of the OIT compares more closely to that of the KLT relative to the performances of the DCT, CMT, and ICT when N=8.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.501-506
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• 1993

An efficient solution algorithm of the optimal load distribution problem with joint torque constraints is presented. Multiple robot system where each robot is rigidly grasping a common object is considered. The optimality criteria used is the sum of weighted norm of the joint torque vectors. The maximum and minimum bounds of each joint torque in arbitrary form are considered as constraints, and the solution that reduces the internal force to zero is obtained. The optimal load distribution problem is formulated as a quadratic optimization problem in R, where I is the number of robots. The general solution can be obtained using any efficient numerial method for quadratic programming, and for dual robot case, the optimal solution is given in a simple analytical form.

• Journal of applied mathematics & informatics
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• 제33권5_6호
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• pp.485-502
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• 2015

A computational method for solving singularly perturbed boundary value problem of differential equation with shift arguments of mixed type is presented. When shift arguments are sufficiently small (o(ε)), most of the existing method in the literature used Taylor's expansion to approximate the shift term. This procedure may lead to a bad approximation when the delay argument is of O(ε). The main idea for this work is to deal with constant shift arguments, which are independent of ε. In the present method, we construct the formally asymptotic solution of the problem using the method of composite expansion. The reduced problem is solved numerically by using operator compact implicit method, and the second problem is solved analytically. Error estimate is derived by using the maximum norm. Numerical examples are provided to support the theoretical results and to show the efficiency of the proposed method.