• Title/Summary/Keyword: 비선형응답

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Elasto-viscoplastic Dynamic Analysis of Subterranean Storage Cavern for Petroleum Reserve (석유비축을 위한 지하저장공동의 탄.점소성 동적해석)

  • 진지섭;김수석
    • Computational Structural Engineering
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    • v.2 no.2
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    • pp.53-62
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    • 1989
  • In recent times, the subterranean caverns for storing crude oils and oil products are increasingly needed. The elasto-VIScoplastic DYNamic finite element analysis program(VISDYN) has been developed in order to investigate dynamic responses of the storage cavity. And validity of the program is studied through a numerical example. Mohr-Coulomb yield criterion is adopted and associated flow rule is assumed. Geometrically nonlinear behaviour is taken into account using a total Lagrangian formulation. In dynamic deformation reponses, the difference between the steady state displacements and the unsteady state ones by the static analysis can be neglected.

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Design of the Self-Tuning Fuzzy Controller for an Induction Motor (유도 전동기를 위한 자기 동조퍼지 제어기 설계)

  • 전광호;이한영;박준열
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1998.10a
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    • pp.236-243
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    • 1998
  • 퍼지 제어기는 유도전동기에 대한 정확한 수학적 모델링의 과정 없이 IF-THEN 규칙으로 제어하는 비선형 제어기로서 과도 응답 특성과 외란에 대한 강인성 면에서 고전 제어 방식보다 우수한 성능을 보여준다. 그러나 입출력 변수의 공간을 균등하게 나누고 일정한 형태의 삼각형 멤버쉽 함수를 이용한 퍼지 제어기는 한정된 성능 이상을 기대할 수없다. 다라서 퍼지 제어기의 성능을 항상시키기 위해서는 멤버쉽 함수의 폭과 위치를 조정하는 것이 필요하다. 본 연구에서는 퍼지 제어기의 각 변수에 할당된 삼각형 멤버쉽 함수의 폭을 유도 전동기의 광범위한 속도에서의 과도 응답 상태에 EK랄 rkqustlzladmfhTJ 유도 전동기의 성능을 향상시키는 방법에 대해 연구하였다.

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Response Surface Modeling by Genetic Programming I: A Directional Derivative-Based Smoothering Method (유전적 프로그래밍을 이용한 응답면의 모델링 I : 방향도함수 기반의 Smoothering 기법)

  • Yeun, Yun-Seog;Rhee, Wook
    • Journal of Information Technology Application
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    • v.3 no.3
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    • pp.1-24
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    • 2001
  • This paper introduces the genetic programming algorithm(GP), which can approximate highly nonlinear functions, as a tool for the modeling of response surfaces. When the response surfaces is approximated, the very small or minimal teaming set should be used, and thus it is almost certain that GP trees will show overfilling that must be avoided at all costs. We present a novel method, calledDDBS(DirectionalDerivative-Based Smoothering), which very effectively eliminates the unwanted behaviors of GP trees such as large peaks, oscillations, and also overfitting. Four illustrative numerical examples are given to demonstrate the performance of the genetic programming algorithm that adopts DDBS.

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On the Convergence Speed of Nonlinear Least-Squares IIR Adaptive Filter (비선형 무한 응답 최소자승형 적응 여파기의 수렴속도에 관한 연구)

  • 김화종
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1987.11a
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    • pp.58-60
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    • 1987
  • In this paper, we investigate an infinite impulse response adaptive digital filter based on the nonlinear least-squares algorithm, and compare its convergence speed to that of a self-orthogonalizing IIR ADF which is known to have fastest convergence. By simulation, it is shown that the NLS IIR ADF converges faster than other known IIR ADF's, especially for a low-order case.

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Nonlinear Frequency Response Analysis of Hydrodynamic Journal Bearing Under External Disturbance (외란을 받는 저널 베어링의 비선형 주파수 응답해석)

  • 노병후;김경웅
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1998.04a
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    • pp.241-245
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    • 1998
  • The traditional approach is to characterize the behavior and performance of fluid film hydrodynamic journal bearings by means of linearized bearing analysis. The objective of this paper is to examine the nonlinear characteristics of the journal bearing when an external sinusoidal shock is given to the system. The oil film force is obtained by solving the finite width Reynolds equation at each time step by the solution of the column method. Frequency response functions obtained from both linear and nonlinear bearing simulations are compared with each other.

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Linearized Modeling Technique for Complex Dynamic Responses Using Proper Orthogonal Decomposition (적합직교분해법을 이용한 복잡한 동적응답의 선형화 모델링 기법)

  • Lee, Soo-Il;Hong, Sang-Hyuk
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.04a
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    • pp.156-159
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    • 2008
  • Proper orthogonal decomposition is a statistical pattern analysis technique for finding the dominant components, called the proper orthogonal modes, in ensembles of spatially distributed data. We present recent ideas based on proper orthogonal decomposition (POD) and detailed experiments that yield new perspectives into the microscale structures. The linearized modeling technique based on POD is very useful to show the principal characteristics of the complex dynamic responses.

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Response of Nonlinear Asymmetric Vibrations of a Circular Plate (원판의 비선형 비대칭진동응답)

  • 여명환;이원경
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.295-301
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    • 2001
  • An investigation into asymmetric vibrations of a clamped circular plate under a hannonic excitation is made. We examine a primary resonance, in which the frequency of excitation is near the natural frequency of an asymmetric mode of the plate. We found not only a response having the form of standing wave but also one having the form of traveling wave, which was not observed by Sridhar, Mook and Nayfeh(1978; Journal of Sound and Vibration 59(2), pp. 159-170).

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Study of nonlinear Control System for the Argonne Advanced Research Reactor (원자로의 비선형제에 관한 연구)

  • 고병준
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.4 no.2
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    • pp.22-28
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    • 1967
  • The Reactor transient and steady state Response Problem is not always satisfied in automatic control to insure safe operation, because all physical systems are nonlinear to some region such as the deadzone of relay and the backlash of gear. The study for nonlinear control system is described by the applying of analog computer with the parameters given by the argonne advanced Research Reactor.

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MMWP 아날로그 광송수신기의 설계

  • 최영완
    • Proceedings of the IEEK Conference
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    • 1999.11a
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    • pp.301-304
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    • 1999
  • 밀리미터파 대역의 아날로그 광전송을 위한 진행파형 (travel ing wave, TW) 전계흡수 광변조기 (electroabsorption modulator, EAM)와 광수신기의 설계에 대해 발표하고자 한다. TW EAM 및 TW 광수신기의 일반적인 형태인 ridge-type의 co-planar waveguide (CPW)구조에서의 마이크로파의 전송특성을 3차원 FDTD로 분석하여 광파와 전파의 속도 정합 등을 이루는 최적화 구조를 설계하였다. TW EAM의 경우 광세기 변조의 비선형 응답특성에 있어서 마이크로파 손실과 소자길이가 RF 신호의 혼변조 왜곡 (intermodulation distortion)과 SFDR (spurious free dynamic range)성능에 미치는 영향도 이론적으로 조사하였다. TW PIN 광수신기의 경우 광파와 마이크로파의 속도정합의 영향과 이전에는 고려되지 않았던 photo-generated 전송자의 진성 영역에서의 transit time이 광수신기의 밴드 폭에 미치는 영향을 분석하여 최적화 설계하였다.

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Position Controller with Adaptive Feedforward Control (피드포워드 적응제어를 사용한 위치제어기)

  • Yoon Myung-Ha;Choi Nam-Yerl;Lee Chi-Hwan
    • Proceedings of the KIPE Conference
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    • 2002.07a
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    • pp.154-157
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    • 2002
  • 본 연구는 관성의 변화, 비선형 마찰 등에 견실한 피드포워드 적응 위치제어기를 제안한다. 제안된 적응 위치제어기의 특징은 제어기 적응파라미터가 위치오차에 기준모델의 속도 정보를 받아들여 셀프 튜닝된다. 이것은 과도응답 특성을 향상시키고, 정상상태의 수렴 시간을 줄여 시스템의 성능을 개선시킨다. 시뮬레이션을 통하여 제안된 피드포워드 적응 위치제어기의 동작과 설계 방법의 타당성을 보였다.

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