• International Journal of Fuzzy Logic and Intelligent Systems
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• 제2권1호
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• pp.38-42
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• 2002

A fast iterative solving method of fuzzy relational equation is proposed. It is derived by eliminating a redundant comparison process in the conventional iterative solving method (Pedrycz, 1983). The proposed method is applied to image reconstruction, and confirmed that the computation time is decreased to 1 / 40 with the compression rate of 0.0625. Furthermore, in order to make any initial solution converge on a reconstructed image with a good quality, a new cost function is proposed. Under the condition that the compression rate is 0.0625, it is confirmed that the root mean square error of the proposed method decreases to 27.34% and 86.27% compared with those of the conventional iterative method and a non iterative image reconstruction method, respectively.

• Journal of applied mathematics & informatics
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• 제4권1호
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• pp.1-16
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• 1997

In this paper we study efficient parallel implementation for hybrid iterative methods BICGSTAB and BICGSTAB $(\ell)$ with ${Well}=2$ on the CRAY C90 and the efficiency of their parallel performance is evaluated. numerical experiments suggest that on the CRAY C90 a parallel inner product algorithm called PDOTB be used for the par-allelization of hybrid iterative methods containing sensitive values of inner products. Lastly it is shown that the number of iterations in which parallel hybrid iterative methods satisfy a certain convergence criterion depends on the number of processors to be used.

• Journal of applied mathematics & informatics
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• 제26권5_6호
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• pp.1233-1245
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• 2008

In this paper, an iterative method is proposed to solve the least-squares problem of matrix equation AXB+CYD=E over unknown matrix pair [X, Y]. By this iterative method, for any initial matrix pair [$X_1,\;Y_1$], a solution pair or the least-norm least-squares solution pair of which can be obtained within finite iterative steps in the absence of roundoff errors. In addition, we also consider the optimal approximation problem for the given matrix pair [$X_0,\;Y_0$] in Frobenius norm. Given numerical examples show that the algorithm is efficient.

• Journal of applied mathematics & informatics
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• 제27권3_4호
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• pp.763-771
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• 2009

T.H. Kim, H.K. Xu, [Convergence of the modified Mann's iteration method for asymptotically strict pseudo-contractions, Nonlinear Anal.(2007),doi:l0.l016/j.na.2007.02.029.] proved the strong convergence for asymptotically strict pseudo-contractions by the classical CQ iterative method. In this paper, we apply the monotone CQ iterative method to modify the classical CQ iterative method of T.H. Kim, H.K. Xu, and to obtain the strong convergence theorems for asymptotically strict pseudo-contractions. In the proved process of this paper, Cauchy sequences method is used, so we complete the proof without using the demi-closedness principle, Opial's condition or others about weak topological technologies. In addition, we use a ingenious technology to avoid defining that F(T) is bounded. On the other hand, we relax the restriction on the control sequence of iterative scheme.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.855-861
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• 2002

This paper demonstrates the reconstruction of input signals from only the measured signal for the simulation and endurance test of automobiles. The aim of this research is concerned with input signal reconstruction using various iterative teaming algorithm under the condition of system characteristics. From a linear to nonlinear systems which provides the output signals are estimated in this algorithm which is based on the frequency domain. Our concerns are that the algorithm can assure an acceptable stability and convergence compared to the ordinary iterative learning algorithm. As a practical application, a f car model with nonlinear damper system is used to verify the restoration of input signal especially with a modified iterative loaming algorithm.

• Journal of electromagnetic engineering and science
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• 제9권1호
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• pp.12-16
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• 2009

This paper presents a new iterative locally one-dimensional [mite-difference time-domain(LOD-FDTD) method that has a simpler formula than the original iterative LOD-FDTD formula[l]. There are fewer arithmetic operations than in the original LOD-FDTD scheme. This leads to a reduction of CPU time compared to the original LOD-FDTD method while the new method exhibits the same numerical accuracy as the iterative ADI-FDTD scheme. The number of arithmetic operations shows that the efficiency of this method has been improved approximately 20 % over the original iterative LOD-FDTD method.

• 한국지능시스템학회논문지
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• 제12권5호
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• pp.393-396
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• 2002

본 논문은 초기 조건 문제의 관점에서 반복 학습 제어기가 proper 해야 할 필요성에 대하여 연구한다. 반복 학습 제어기가 proper하지 않으면, 모든 반복에 있어서 시스템의 초기 상태와 요구되는 시스템의 상태가 완전히 일치하지 않는다면 학습입력의 크기가 무한대로 증가하는 경우가 생겨 실제 구현이 불가능해진다. 따라서 이론적으로 학습 제어의 수렴이 보장되더라도 proper하지 않은 학습 제어기는 실제 시스템에는 적용할 수 없음을 보인다. 또한 반복 학습 제어 시스템의 초기 조건의 불일치가 시스템의 수렴 특성에 미치는 영향에 대하여 분석한다.

• Structural Engineering and Mechanics
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• 제14권1호
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• pp.57-70
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• 2002

This work presents an iterative mesh partitioning approach to improve the efficiency of parallel substructure finite element computations. The proposed approach employs an iterative strategy with a set of empirical rules derived from the results of numerical experiments on a number of different finite element meshes. The proposed approach also utilizes state-of-the-art partitioning techniques in its iterative partitioning kernel, a cost function to estimate the computational cost of each submesh, and a mechanism that adjusts element weights to redistribute elements among submeshes during iterative partitioning to partition a mesh into submeshes (or substructures) with balanced computational workloads. In addition, actual parallel finite element structural analyses on several test examples are presented to demonstrate the effectiveness of the approach proposed herein. The results show that the proposed approach can effectively improve the efficiency of parallel substructure finite element computations.

• Journal of Electrical Engineering and Technology
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• 제13권4호
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• pp.1705-1714
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• 2018

This paper develops a novel controller called iterative learning sliding mode (ILSM) to control linear and nonlinear fractional-order systems. This control applies a combination structures of continuous and discontinuous controller, conducts the system output to the desired output and achieve better control performance. This controller is designed in the way to be robust against the external disturbance. It also estimates unknown parameters of fractional-order systems. The proposed controller unlike the conventional iterative learning control for fractional systems does not need to apply direct control input to output of the system. It is shown that the controller perform well in partial and complete observable conditions. Simulation results demonstrate very good performance of the iterative learning sliding mode controller for achieving the desired control objective by increasing the number of iterations in the control loop.

• 대한전자공학회논문지SP
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• 제46권3호
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• pp.60-67
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• 2009

위상복원문제 (Phase retrieval problem)은 어떤 신호의 푸리에 변환의 크기로부터 신호를 구하거나 푸리에 변환의 위상을 구하는 문제이다. 이 문제는 천문학, X-선 결정학 등 많은 물리적인 문제에서 발생하고 있으며, 최근에는 고출력 레이저를 이용하여 인공별을 만들 수 있게 됨에 따라 많은 필요성이 대두될 것으로 예측되는 분야이다. 일반적으로 신호의 푸리에 변환의 크기만으로는 유일하게 해를 구할 수 없으며, 원하는 해를 구하기 위하여 구하고자 하는 신호에 여러 가지 제약 조건을 주어 유일한 해를 갖도록 연구를 진행하여 왔다. 이 논문에서는 원 신호의 푸리에 크기 외에, 구하고자 하는 신호에 알고있는 신호를 더한 신호의 푸리에 크기를 이용하여, iterative 한 방법으로 신호를 복원하는 문제에 대하여 다룬다. 원하는 신호를 구하기 위하여 간략하게, 이론적인 배경과 iterative 알고리즘을 소개하고, 이 알고리즘이 구하고자 하는 신호로 수렴한다는 것을 보인다.