• Title/Summary/Keyword: 비선형 외삽법

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Nonlinear Extrapolation Based Image Restoration Using Region Classification (지역 분할을 통한 비선형 외삽법 기반 영상 복원 기법)

  • Han, Jong-Woo;Hwang, Mn-Cheol;Wang, Tae-Shick;Ko, Sung-Jea
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.46 no.3
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    • pp.105-111
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    • 2009
  • In this paper, we propose a locally adaptive image restoration method based on nonlinear extrapolation in frequency domain. In general, the conventional method causes ringing artifacts on the object boundary. To solve this problem, we introduce an improved restoration method which considers textures of an image block. In the proposed method, a blurred image is divided into several blocks, and each block is classified into three groups; simple, one edge, and complex blocks according to the contained texture. Depending on the classification result, adaptive nonlinear extrapolation is applied to each block in a blurred image. Experimental results show that the proposed algorithm can achieve higher quality image in both subjective and objective views as compared with the conventional method.

Estimations of the student numbers by nonlinear regression model (비선형 회귀모형을 이용한 학년별 학생수 추계)

  • Yoon, Yong-Hwa;Kim, Jong-Tae
    • Journal of the Korean Data and Information Science Society
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    • v.23 no.1
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    • pp.71-77
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    • 2012
  • This paper introduces the projection methods by nonlinear regression model. To predict the student numbers, a log model and an involution model as the kind of a trend-extrapolation method are used. Empirical evidence shows that a projection by log model is better than by involution model with the confidence interval estimations for the coefficients of determination.

An Experimental Study of Pipkin-Rogers Model for Automotive Bushing (자동차 부싱에 대한 Pipkin-Rogers 모델의 실험적 연구)

  • Kim, Sung-Jin;Lee, Su-Young;Lee, Seong-Beom
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.11 s.176
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    • pp.118-124
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    • 2005
  • An automotive bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is a hollow cylinder, which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the force applied to the shaft and the relative deformation of a bushing is nonlinear and exhibits features of viscoelasticity. In this paper, an automotive bushing is regarded as nonlinear viscoelastic incompressible material. Instron 8801 equipment was used for experimental res earch and ramp-to-constant displacement control test was used for data acquisition. Displacement dependent force relaxation function was obtained from the force extrapolation method and expressed as the explicit combination of time and displacement. Pipkin-Rogers model, which is the direct relation of force and displacement, was obtained and comparison studies between the experimental results and the Pipkin-Rogers results were carried out.

Forward Projection Using Fuzzy Logic in Axisymmetric Finite Element Simulation for Cold Forging (축대칭 냉간단조의 유한요소해석에서 퍼지로직을 이용한 전방투사법)

  • 정낙면;이낙규;양동열
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.8
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    • pp.1468-1484
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    • 1992
  • In the present paper forward projection is proposed as a new approach to determine the preform shape in rib-web type forging. In the forward projection technique an optimal billet is determined by applying some mathematical relationship between geometrical trials in the initial billet shape and the final products. In forward projection a volume difference between the desired product shape and the final computed shape obtained by the rigid-plastic finite element method is used as a measure of incomplete filling of working material in the die. At first linear inter-/extrapolation is employed to find a proper trial shape for the initial billet and the method is successfully applied to some cases of different aspect ratios of the initial billet. However, when the initial guesses are not sufficiently near the optimal value linear inter-/extrapolation does not render complete die filling. For more general application, a fuzzy system is used in the forward projection technique in order to determine the initial billet shape for rib-web type forging. It has been thus shown that the fuzzy system is more reliable for the preform design in the rib-web type forging process.