• 제목/요약/키워드: approximation theory

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ON INVARIANT APPROXIMATION OF NON-EXPANSIVE MAPPINGS

  • Sharma, Meenu;Narang, T.D.
    • 한국수학교육학회지시리즈B:순수및응용수학
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    • 제10권2호
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    • pp.127-132
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    • 2003
  • The object of this paper is to extend and generalize the work of Brosowski [Fixpunktsatze in der approximationstheorie. Mathematica Cluj 11 (1969), 195-200], Hicks & Humphries [A note on fixed point theorems. J. Approx. Theory 34 (1982), 221-225], Khan & Khan [An extension of Brosowski-Meinardus theorem on invariant approximation. Approx. Theory Appl. 11 (1995), 1-5] and Singh [An application of a fixed point theorem to approximation theory J. Approx. Theory 25 (1979), 89-90; Application of fixed point theorem in approximation theory. In: Applied nonlinear analysis (pp. 389-394). Academic Press, 1979] in metric spaces having convex structure, and in metric linear spaces having strictly monotone metric.

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비 최소위상 시스팀에 대한 LQG/LTR 연구 - 최적 근사화 방법 (A Study on the LQG/LTR for Nonminimum phase plant : Optimal Approximation method)

  • 서병설;강진식;이준영
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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    • pp.191-196
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    • 1991
  • LQG/LTR method have a theoretical constraint that it cannot applied to nonminimum phase plant. In this paper, we suggest two methods of approximation of minimum phase plant for a given nonminimum phase plant to solve this constraint. Error is described by additive form which can reduce its magnitude in broad frequency range. A optimal approximation method was suggesetd by using Hankel operator theory and Nehari theory. It is showen by example that the methods suggested can resolve the frequency domain constraint arised in Stein and Athans approximation.

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비 최소위상 플랜트에 대한 LQG/LTR에 관한 연구(I) : 최적 근사 방법 (A Study on the LQG/LTR for Nonminimum Phase Plant (I) : Optimal Approximation Method)

  • 강진식;서병설
    • 한국통신학회논문지
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    • 제16권10호
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    • pp.972-980
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    • 1991
  • LQG/LTR method have a theoretical constraint that it cannot applied to nonminimum phase plant. In this paper we suggest two methods of approximation of minimum phase plant for a given nonminimum phase plant to solve this constraint. Error is described by additive form which can reduce its magnitude in broad frequency range. A optimal approximation method was suggested by using Hankel operator theory and Nehan theory it is shown by example that the methods suggested can resolve the frequency domain constraint arised in Stein and Athans approximation.

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확장된 근사 알고리즘을 이용한 조합 방법 (Rule of Combination Using Expanded Approximation Algorithm)

  • 문원식
    • 디지털산업정보학회논문지
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    • 제9권3호
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    • pp.21-30
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    • 2013
  • Powell-Miller theory is a good method to express or treat incorrect information. But it has limitation that requires too much time to apply to actual situation because computational complexity increases in exponential and functional way. Accordingly, there have been several attempts to reduce computational complexity but side effect followed - certainty factor fell. This study suggested expanded Approximation Algorithm. Expanded Approximation Algorithm is a method to consider both smallest supersets and largest subsets to expand basic space into a space including inverse set and to reduce Approximation error. By using expanded Approximation Algorithm suggested in the study, basic probability assignment function value of subsets was alloted and added to basic probability assignment function value of sets related to the subsets. This made subsets newly created become Approximation more efficiently. As a result, it could be known that certain function value which is based on basic probability assignment function is closely near actual optimal result. And certainty in correctness can be obtained while computational complexity could be reduced. by using Algorithm suggested in the study, exact information necessary for a system can be obtained.

거문고 괘율에 관한 군론적 근사화 모형 개발 연구 (A Study on Group Theoretic Approximation Model for Gwaeyul of Geomungo)

  • 신현용
    • 한국수학교육학회지시리즈E:수학교육논문집
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    • 제28권3호
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    • pp.367-374
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    • 2014
  • 최근 거문고 괘율에 관한 수학적 모형이 제안되었다. 이 수학적 모형은 군론으로 기술할 수 있다. 이 논문은 수학과 거문고를 주제로 하는 학문 간의 연계로서 거문고 괘율에 관한 이론을 군론으로 설명한다.

THE COMPUTATION OF MULTIVARIATE B-SPLINES WITH APPLICATION TO SURFACE APPROXIMATIONS

  • KIM, HOI SUB
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제3권1호
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    • pp.81-98
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    • 1999
  • In spite of the well developed theory and the practical use of the univariate B-spline, the theory of multivariate B-spline is very new and waits its practical use. We compare in this article the multivariate B-spline approximation with the polynomial approximation for the surface fitting. The graphical and numerical comparisons show that the multivariate B-spline approximation gives much better fitting than the polynomial one, especially for the surfaces which vary very rapidly.

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A Generalization of S. P. Singh's T-invariant Point Theorem to Approximation Theory

  • Cho, Yeol Je
    • 한국수학교육학회지시리즈A:수학교육
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    • 제18권1호
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    • pp.21-23
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    • 1980
  • In [3], an extension of B. Brosowski s T-invariant Point Theorem is given where the linearity of the function and the convexity of the set are relaxed. In this paper, our main purpose is to generalize S. P. Singh's T-invariant Point Theorem to Approximation Theory.

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불규칙 경계면에 대한 중저주파수 간섭 반사 계수 유도 (Derivation of Coherent Reflection Coefficient at Mid and Low Frequency for a Rough Surface)

  • 추영민;성우제;변성훈;김시문
    • 한국음향학회지
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    • 제28권3호
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    • pp.174-186
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    • 2009
  • 경계면이 존재하는 해양에서의 수중 음파 전달 모델링 시 일반적으로 평평한 경계면을 가정하고 Rayleigh가 제안했던 반사계수를 이용해 반사파를 계산할 수 있다. 하지만 해수면이나 해저면과 같은 실제 해양의 경계면은 불규칙적인 거칠기를 가진다. 이러한 경계면에서의 반사 손실은 실험식이나 산란 이론에 기반한 간섭 반사 계수를 계산하여 구할 수 있다. 본 논문에서는 섭동 이론, Kirchhoff 근사법, 작은 가지 근사법과 같은 산란 이론을 이용하여 유체-유체 경계면에 대한 간섭 반사 계수를 각각 유도한다. 이를 이용하여 임의의 거칠기를 가지는 해수면과 해저면에 대한 각 산란 이론의 간섭 반사계수를 계산하며, 이 결과를 Rayleigh 반사 계수와 비교하여 경계면의 거칠기에 따른 반사 손실을 분석한다. 또한, 섭동 이론과 Kirchhoff 근사법의 결과를 일반적으로 적용 범위가 넓은 작은 기울기 근사법의 결과와 비교하여 각 이론의 유효범위에 대해 고찰한다.