• Title/Summary/Keyword: fourier Transform

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FOURIER-FEYNMAN TRANSFORM AND CONVOLUTION OF FOURIER-TYPE FUNCTIONALS ON WIENER SPACE

  • Kim, Byoung Soo
    • East Asian mathematical journal
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    • 제29권5호
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    • pp.467-479
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    • 2013
  • We develop a Fourier-Feynman theory for Fourier-type functionals ${\Delta}^kF$ and $\widehat{{\Delta}^kF}$ on Wiener space. We show that Fourier-Feynman transform and convolution of Fourier-type functionals exist. We also show that the Fourier-Feynman transform of the convolution product of Fourier-type functionals is a product of Fourier-Feynman transforms of each functionals.

CONDITIONAL FOURIER-FEYNMAN TRANSFORMS OF VARIATIONS OVER WIENER PATHS IN ABSTRACT WIENER SPACE

  • Cho, Dong-Hyun
    • 대한수학회지
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    • 제43권5호
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    • pp.967-990
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    • 2006
  • In this paper, we evaluate first variations, conditional first variations and conditional Fourier-Feynman transforms of cylinder type functions over Wiener paths in abstract Wiener space and then, investigate relationships among first variation, conditional first variation, Fourier-Feynman transform and conditional Fourier-Feynman transform of those functions. Finally, we derive the conditional Fourier-Feynman transform for the product of cylinder type function which defines the functions in a Banach algebra introduced by Yoo, with n linear factors.

더해지는 기준신호를 이용한 위성복원: I. 이론 (Phase Retrieval Using an Additive Reference Signal: I. Theory)

  • Woo Shik Kim
    • 전자공학회논문지B
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    • 제31B권5호
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    • pp.26-33
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    • 1994
  • Phase retrieval is concerned with the reconstruction of a signal from its Fourier transform magnitude (or intensity), which arises in many areas such as X-ray crystallography, optics, astronomy, or digital signal processing. In such areas, the Fourier transform phase of the desired signal is lost while measuring Fourier transform magnitude (F.T.M.). However, if a reference 'signal is added to the desired signal, then, in the Fourier trans form magnitude of the added signal, the Fourier transform phase of the desired signal is encoded. This paper addresses uniqueness and retrieval of the encoded Fourier phase of a multidimensional signal from the Fourier transform magnitude of the added signal along with the Fourier transform magnitude of the desired signal and the information of the additive reference signal. In Part I, several conditions under which the desired signal can be uniquely specified from the two Fourier transform magnitudes and the additive reference signal are presented. In Part II, the development of non-iterative algorithms and an iterative algorithm that may be used to reconstruct the desired signal(s) is considered.

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더해지는 기준신호를 이용한 위성복원: II. 복원 (Phase Retrieval Using an Additive Reference Signal: II. Reconstruction)

  • Woo Shik Kim
    • 전자공학회논문지B
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    • 제31B권5호
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    • pp.34-41
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    • 1994
  • Phase retrieval is concerned with the reconstruction of a signal from its Fourier transform magnitude (or intensity), which arises in many areas such as X-ray crystallography, optics, astronomy, or digital signal processing In such areas, the Fourier transform phase of the desired signal is lost while measuring Fourier transform magnitude (F.T.M.). However, if a reference 'signal is added to the desired signal, then, in the Fourier trans form magnitude of the added signal, the Fourier transform phase of the desired signal is encoded This paper addresses uniqueness and retrieval of the encoded Fourier phase of a multidimensional signal from the Fourier transform magnitude of the added signal along with Fourier transform magnitude of the desired signal and the information of the additive reference signal In Part I, several conditions under which the desired signal can be uniquely specified from the two Fourier transform magnitudes and the additive reference signal are presented In Part II, the development of non-iterative algorithms and an iterative algorithm that may be used to reconstruct the desired signal (s) is considered

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Fractional Fourier 변환을 이용한 LFM 신호 분리 (LFM Signal Separation Using Fractional Fourier Transform)

  • 석종원;김태환;배건성
    • 한국정보통신학회논문지
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    • 제17권3호
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    • pp.540-545
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    • 2013
  • Fractional 푸리에변환(Fractional Fourier Transform : FRFT)은 기존의 푸리에 변환의 일반화된 형태로서, 양자역학분야에서 처음 소개되었다. FRFT가 가지는 시간-주파수 영역에서의 단순하면서도 유용한 특성으로 인하여, 지금까지 소나 및 레이더 신호처리 분야에서 많은 연구결과들이 발표되었으며, 푸리에 변환을 활용한 기존의 방법보다 우수한 연구결과를 보여 왔다. 본 논문에서는 LFM(Linear Frequency Modulation)신호들이 겹쳐져 수신되었을 경우에 이들 신호들을 검출하고 분리하기 위해 FRFT를 이용하였다. 실험결과 수신된 LFM 신호들을 FRFT 영역에서 효율적으로 검출하고 분리가 가능함을 확인하였다.

Abel-Fourier법과 디지탈 선형필터법과의 비교 (A Comparison between Abel-Fourier and Digital Linear Filter Methods)

  • 김희준
    • 자원환경지질
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    • 제20권2호
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    • pp.119-123
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    • 1987
  • 0차의 Hankel 변환은 Abel 변환과 Fourier 변환의 결합으로 나타낼 수 있다. 이 Abel-Fourier법은 샘플링 간격이 일정하지 않는 중합필터를 사용한 신속한 Abel 변환과 고속 Fourier 변환으로 작성될 때, 종래의 디지탈 선형필터법보다 계산시간면에서 유리하다. 그러나, Abel-Fourier법은 일반적으로 잘 설계된 디지탈 필터보다 정확하지는 않다. 전기탐사 문제에 이들 방법을 적용할 때, 디지탈 필터법이 Abel-Fourier 법보다 더 융통성이 많은 것으로 생각된다.

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Implementatin of the Discrete Rotational Fourier Transform

  • Ahn, Tae-Chon
    • The Journal of the Acoustical Society of Korea
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    • 제15권3E호
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    • pp.74-77
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    • 1996
  • In this paper we implement the Discrete Rotational Fourier Transform(DRFT) which is a discrete version of the Angular Fourier Transform and its inverse transform. We simplify the computation algorithm in [4], and calculate the complexity of the proposed implementation of the DRFT and the inverse DRFT, in comparison with the complexity of a DFT (Discrete Fourier Transform).

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CONDITIONAL GENERALIZED FOURIER-FEYNMAN TRANSFORM OF FUNCTIONALS IN A FRESNEL TYPE CLASS

  • Chang, Seung-Jun
    • 대한수학회논문집
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    • 제26권2호
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    • pp.273-289
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    • 2011
  • In this paper we dene the concept of a conditional generalized Fourier-Feynman transform on very general function space $C_{a,b}$[0, T]. We then establish the existence of the conditional generalized Fourier-Feynman transform for functionals in a Fresnel type class. We also obtain several results involving the conditional transform. Finally we present functionals to apply our results. The functionals arise naturally in Feynman integration theories and quantum mechanics.