• Title/Summary/Keyword: iterative process

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Fast iterative image restoration algorithms based on preconditioning (전처리기를 사용한 반복적 영상복원의 고속화 기법)

  • 백준기;문준일;김상구
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.33B no.12
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    • pp.62-70
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    • 1996
  • Image restoration is the process which estimates the original image form the blurred image observed by the non-ideal imaging system with additivenoise. According to the regularized approach, the resotred image can be obtained by iterative methods or the constrained least square error(CLS) filter. Among those retoratin methods, despite of many advantages, iterative iamge restoration is limited in use because of slow convergence. In the present paper, fast iterative image restoration algorithms based on preconditoning are proposed. The preconditioner can be obtained by using the characteristics finite impulse response (FIR) filter structure.

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FEM-BEM iterative coupling procedures to analyze interacting wave propagation models: fluid-fluid, solid-solid and fluid-solid analyses

  • Soares, Delfim Jr.
    • Coupled systems mechanics
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    • v.1 no.1
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    • pp.19-37
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    • 2012
  • In this work, the iterative coupling of finite element and boundary element methods for the investigation of coupled fluid-fluid, solid-solid and fluid-solid wave propagation models is reviewed. In order to perform the coupling of the two numerical methods, a successive renewal of the variables on the common interface between the two sub-domains is performed through an iterative procedure until convergence is achieved. In the case of local nonlinearities within the finite element sub-domain, it is straightforward to perform the iterative coupling together with the iterations needed to solve the nonlinear system. In particular, a more efficient and stable performance of the coupling procedure is achieved by a special formulation that allows to use different time steps in each sub-domain. Optimized relaxation parameters are also considered in the analyses, in order to speed up and/or to ensure the convergence of the iterative process.

Temperature Uniformity Control of Wafer During Vacuum Soldering Process (진공 솔더링 공정 중 웨이퍼 온도균일화 제어)

  • Kang, Min Sig;Jee, Won Ho;Yoon, Wo Hyun
    • Journal of the Semiconductor & Display Technology
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    • v.11 no.2
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    • pp.63-69
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    • 2012
  • As decreasing size of chips, the need of wafer level packaging is increased in semi-conductor and display industries. Temperature uniformity is a crucial factor in vacuum soldering process to guarantee quality of bonding between chips and wafer. In this paper, a stepwise iterative algorithm has been suggested to obtain output profile of each heat source. Since this algorithm is based on open-loop stepwise iterative experimental technique, it is easier to implement and cost effective than real time feedback controls. Along with some experiments, it was shown that the suggested algorithm can remarkably improve temperature uniformity of wafer during whole heating process compared with the ordinary manual trial-and error method.

INERTIAL PICARD NORMAL S-ITERATION PROCESS

  • Dashputre, Samir;Padmavati, Padmavati;Sakure, Kavita
    • Nonlinear Functional Analysis and Applications
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    • v.26 no.5
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    • pp.995-1009
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    • 2021
  • Many iterative algorithms like that Picard, Mann, Ishikawa and S-iteration are very useful to elucidate the fixed point problems of a nonlinear operators in various topological spaces. The recent trend for elucidate the fixed point via inertial iterative algorithm, in which next iterative depends on more than one previous terms. The purpose of the paper is to establish convergence theorems of new inertial Picard normal S-iteration algorithm for nonexpansive mapping in Hilbert spaces. The comparison of convergence of InerNSP and InerPNSP is done with InerSP (introduced by Phon-on et al. [25]) and MSP (introduced by Suparatulatorn et al. [27]) via numerical example.

Fast Iterative Solving Method of Fuzzy Relational Equation and its Application to Image Compression/Reconstruction

  • Nobuhara, Hajime;Takama, Yasufumi;Hirota, Kaoru
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.2 no.1
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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.

Robust tuning of quadratic criterion-based iterative learning control for linear batch system

  • Kim, Won-Cheol;Lee, Kwang-Soon
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10a
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    • pp.303-306
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    • 1996
  • We propose a robust tuning method of the quadratic criterion based iterative learning control(Q-ILC) algorithm for discrete-time linear batch system. First, we establish the frequency domain representation for batch systems. Next, a robust convergence condition is derived in the frequency domain. Based on this condition, we propose to optimize the weighting matrices such that the upper bound of the robustness measure is minimized. Through numerical simulation, it is shown that the designed learning filter restores robustness under significant model uncertainty.

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ON ITERATIVE APPROXIMATION OF COMMON FIXED POINTS OF ASYMPTOTICALLY NONEXPANSIVE MAPPINGS WITH APPLICATIONS

  • Kim, Jong Kyu;Qin, Xiaolong;Lim, Won Hee
    • East Asian mathematical journal
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    • v.28 no.5
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    • pp.617-630
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    • 2012
  • In this paper, the problem of iterative approximation of common fixed points of asymptotically nonexpansive is investigated in the framework of Banach spaces. Weak convergence theorems are established. A necessary and sufficient condition for strong convergence is also discussed. As an application of main results, a variational inequality is investigated.

An Effective Detection of Bimean and its Application into Image Segmentation by an Interative Algorithm Method (반복적인 알고리즘 방법에 의한 효과적인 양평균 검출 및 영상분할에 응용)

  • Heo, Pil-U
    • 연구논문집
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    • s.25
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    • pp.147-154
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    • 1995
  • In this paper, we discussed the convergence and the properties of an iterative algorithm method in order to improve a bimean clustering algorithm. This algorithm that we have discussed choose automatically an optimum threshold as a result of an iterative process, successive iterations providing increasingly cleaner extractions of the object region, The iterative approach of a proposed algorithm is seen to select an appropriate threshold for the low contrast images.

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