• Title/Summary/Keyword: Nonlinear function

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다중 심볼 비선형 연속 위상 주파수 천이 변조 (Multiple-symbol Nonlinear Continuous Phase Frequency Shift Keying)

  • 주판유;송명규;홍성권;강성진;강창언
    • 한국통신학회논문지
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    • 제21권10호
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    • pp.2660-2669
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    • 1996
  • In this paper, it is called nonlinear-symbol CPFSK(NCPFSK) which is modulated by the nonlinear function of information carrying phase function within all symbol interval produce time invariant trellis structure. In general, the bit error probability performance of CPFSK modultion scheme within given signal constellation is determined from the number of memory elementsof continuous phase encoder, i.e. number of state. In this paper the number of state of analyticall designed NCPFSK is time invariant. And the nonlinear symbol mapping function of the proposed moudlation produces the nonlinear symbol andthe phase state of the modulation for updating the phase function of NCPFSK. It si shown in this paper nonlinear symbol CPFSK with multiple TCM to make further improvements in d$^{2}$, and analyzed BER performance in AWGN channel envioronments.hannel envioronments.

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Estimation of kernel function using the measured apparent earth resistivity

  • Kim, Ho-Chan;Boo, Chang-Jin;Kang, Min-Jae
    • International journal of advanced smart convergence
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    • 제9권3호
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    • pp.97-104
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    • 2020
  • In this paper, we propose a method to derive the kernel function directly from the measured apparent earth resistivity. At this time, the kernel function is obtained through the process of solving a nonlinear system. Nonlinear systems with many variables are difficult to solve. This paper also introduces a method for converting nonlinear derived systems to linear systems. The kernel function is a function of the depth and resistance of the Earth's layer. Being able to derive an accurate kernel function means that we can estimate the earth parameters i.e. layer depth and resistivity. We also use various Earth models as simulation examples to validate the proposed method.

다중 비선형 S-box 함수를 이용한 블록 암호시스템 설계 (A Design of Block Cryptosystem using Multiple Nonlinear S-box Function)

  • 정우열;이선근
    • 한국컴퓨터정보학회논문지
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    • 제6권2호
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    • pp.90-96
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    • 2001
  • 네트워크의 발전은 통신망의 발전과 더불어 심각한 사회문제를 발생시킨다. 즉, 보안에 관련된 문제는 네트워크를 사용할 경우 해킹과 크래킹에 대하여 더욱 주의해야 한다는 것이다. 본 논문에서는 키분배 및 키길이에 관한 결정론적 문제점에 무관하게 암호화를 수행할 수 있는 다중 비선형 S-box 함수(Multiple nonlinear S-box function)를 사용하는 블록 암호시스템을 제안하고 하드웨어를 설계하였다. 제안된 다중 비선형 S-box는 암호화에사용되어지는 키 데이터에 대하여 비선형 함수를 다중으로 사용하여 비도를 증가시켰으며DC 및 LC에 의한 암호해석을 방지하기 위하여 MDP, MLP를 최대로 할 수 있도록 하였다. 본 논문에서 제안한 다중 비선형 S-box 함수는 Synopsys Ver. 1999.10과 VHDL을 사용하여 회로합성 및 모의실험을 수행하였다.

Sliding Mode Control with Nonlinear Interpolation in Variable Boundary Layer

  • Kim, Yookyung;Jeon, Gijoon
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2002년도 ICCAS
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    • pp.35.1-35
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    • 2002
  • $\textbullet$ Sliding mode control (SMC) with nonlinear interpolation in variable boundary layer (VBL) is proposed $\textbullet$ A sigmoid function is used for nonlinear interpolation in VBL. $\textbullet$ The Parameter of the sigmoid function is tuned by fuzzy controller $\textbullet$ The choice of parameter for the sigmoid function is guided by FC. $\textbullet$ The parameter is continuously updated as boundary layer thickness varies. $\textbullet$ The proposed method hasbetter tracking performance than the conventional linear interpolation $\textbullet$ To demonstrate its performance the proposed control algorithm is applied to a nonlinear system.

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An Approach to a Formal Linearization toy Time-variant Nonlinear Systems using Polynomial Approximations

  • Komatsu, Kazuo;Takata, Hitoshi
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2002년도 ICCAS
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    • pp.52.2-52
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    • 2002
  • In this paper we consider an approach to a formal linearization for time-variant nonlinear systems. A time-variant nonlinear sysetm is assumed to be described by a time-variant nonlinear differential equation. For this system, we introduce a coordinate transformation function which is composed of the Chebyshev polynomials. Using Chebyshev expansion to the state variable and Laguerre expansion to the time variable, the time-variant nonlinear sysetm is transformed into the time-variant linear one with respect to the above transformation function. As an application, we synthesize a time-variant nonlinear observer. Numerical experiments are included to demonstrate the validity of...

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비선형 히스토그램 평활화 함수에 의한 의료영상의 화질개선 (Quality Enhancement of Medical Images by Using Nonlinear Histogram Equalization Function)

  • 조용현
    • 한국산업융합학회 논문집
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    • 제13권1호
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    • pp.23-30
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    • 2010
  • This paper presents a histogram equalization based on the nonlinear transformation function for enhancing the quality of medical images. The nonlinear transformation function is applied to adaptively equalize the brightness of the image according to its intensity level frequency. The logistic function is used as a nonlinear transformation function, which is calculated by only using the intensity level with maximum frequency and the maximum intensity level in an histogram, and the total number of pixels. The proposed method has been applied for equalizing 8 medical images with a different resolution and histogram distribution. The experimental results show that the proposed method has the superior enhancement performances compared with the conventional histogram equalization. And the proposed histogram equalization can be used in various multimedia systems in real-time.

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비선형 함수 근사화를 사용한 TD학습에 관한 연구 (A study of Temperal Difference Learning using Nonlinear Function Approximation)

  • 권재철;이영석;김독옥;서보혁
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1998년도 추계학술대회 논문집 학회본부 B
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    • pp.407-409
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    • 1998
  • This paper deals with temporal-difference learning that is a method for approximating long-term future cost as a function of current state in knowlege-poor environment, a function approximator is used to approximate the mapping from state to future cost, a linear function approximator is limited because mapping from state to future cost has a nonlinear characteristic, so a nonlinear function approximator is used to approximate the mapping from state to future cost in this paper, and that TD learning using a nonlinear function approximator is stable is proved.

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THE CONVERGENCE OF A DUAL ALGORITHM FOR NONLINEAR PROGRAMMING

  • Zhang, Li-Wei;He, Su-Xiang
    • Journal of applied mathematics & informatics
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    • 제7권3호
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    • pp.719-738
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    • 2000
  • A dual algorithm based on the smooth function proposed by Polyak (1988) is constructed for solving nonlinear programming problems with inequality constraints. It generates a sequence of points converging locally to a Kuhn-Tucker point by solving an unconstrained minimizer of a smooth potential function with a parameter. We study the relationship between eigenvalues of the Hessian of this smooth potential function and the parameter, which is useful for analyzing the effectiveness of the dual algorithm.

Support vector quantile regression for autoregressive data

  • Hwang, Hyungtae
    • Journal of the Korean Data and Information Science Society
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    • 제25권6호
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    • pp.1539-1547
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    • 2014
  • In this paper we apply the autoregressive process to the nonlinear quantile regression in order to infer nonlinear quantile regression models for the autocorrelated data. We propose a kernel method for the autoregressive data which estimates the nonlinear quantile regression function by kernel machines. Artificial and real examples are provided to indicate the usefulness of the proposed method for the estimation of quantile regression function in the presence of autocorrelation between data.

A NUMERICAL METHOD FOR SOLVING THE NONLINEAR INTEGRAL EQUATION OF THE SECOND KIND

  • Salama, F.A.
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제7권2호
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    • pp.65-73
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    • 2003
  • In this work, we use a numerical method to solve the nonlinear integral equation of the second kind when the kernel of the integral equation in the logarithmic function form or in Carleman function form. The solution has a computing time requirement of $0(N^2)$, where (2N +1) is the number of discretization points used. Also, the error estimate is computed.

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