• 제목/요약/키워드: Taylor

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Taylor 모델을 사용한 전력계통의 안정화 (Power System Stabilizer Using Taylor Model)

  • 김호찬;김세호
    • 조명전기설비학회논문지
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    • 제17권5호
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    • pp.111-117
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    • 2003
  • 제안한 Taylor모델 개념은 단지 입출력 데이터만을 이용하여 제어기를 설계하기 위해 사용되는데, Taylor모델의 매개변수는 입출력 데이터들을 사용하여 추정되고 제어기는 Taylor모델을 통하여 얻어진다. Taylor모델 근사화의 정확성은 관측창의 크기와Taylor모델의 차수가 커짐에 따라 좋아진다. Taylor모델을 이용한 전력계통의 안정화를 위해 LQR 제어기가 제안되고 컴퓨터 시뮬레이션을 통해 기존의 방법과의 성능을 비교한다.

실린더의 회전 주파수 진동이 Taylor 와류에 미치는 영향 (EFFECTS OF OSCILLATING FREQUENCY ON TAYLOR VORTICES)

  • 강창우;양경수
    • 한국전산유체공학회지
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    • 제14권3호
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    • pp.95-105
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    • 2009
  • We study time-periodic Taylor-Couette flow with the outer cylinder at rest and the inner one oscillating with a mean angular velocity. Varying the frequency of inner cylinder, we investigate the change of Taylor vortices at a given amplitude and a mean angular velocity. With a small frequency of modulation, we find that Taylor vortices appear and disappear periodically. With a higher frequency, Taylor vortices do not disappear, but the intensity of Taylor vortices modulates periodically. As the frequency increases, Taylor vortices modulate harmonically.

Taylor 정리의 역사적 고찰과 교수방안 (A History of Taylor's Theorem and Its Teaching Strategy)

  • 김성옥
    • 한국수학사학회지
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    • 제31권1호
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    • pp.19-35
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    • 2018
  • Taylor's Theorem is an important theorem which is applied to several disciplines. It is usually taught in a college-level calculus course for the first time. Many students have a hard time to understand or to make applications. In this paper, we look into the history of the development of Taylor's theorem and consider a teaching strategy of the theorem.

진동하는 Taylor-Couette 유동에 대한 수치적 연구 (NUMERICAL STUDY OF MODULATED TAYLOR-COUETTE FLOW)

  • 강창우;양경수
    • 한국전산유체공학회지
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    • 제15권4호
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    • pp.32-39
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    • 2010
  • In this study, we consider Taylor-Couette flow with the outer cylinder at rest and the inner one oscillating with a mean angular velocity. Varying the mean angular velocity, amplitude and frequency of the oscillation, we investigate the characteristics of modulated Taylor vortices. At a constant mean angular velocity, Taylor vortices intensify as the amplitude increases and frequency decreases. The axial wavenumber is calculated by spectral analysis. When the frequency varies, the axial wavenumber does not change at a constant mean angular velocity and amplitude. But, the axial wavenumber increases, as the mean angular velocity increases.

Wavy Taylor-Couette 유동에 대한 전산해석 (I) -축방향 유동이 없는 경우- (Numerical Study of Wavy Taylor-Couette Flow(I) -Without an Axial Flow-)

  • 황종연;양경수
    • 대한기계학회논문집B
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    • 제25권5호
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    • pp.697-704
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    • 2001
  • The flow between two concentric cylinders, with the inner one rotating, is studied using numerical simulation. This study considers the identical flow geometry as in the experiments of Wereley and Lueptow[J. Fluid Mech., 364, 1998]. They carried out experiment using PIV to measure the velocity fields in a meridional plane of the annulus in detail. When Taylor number increases over the critical one, the flow instability caused by curved streamlines of the tangential flow induces Taylor vortices in the flow direction. As Taylor number further increases over another critical one, the steady Taylor vortices become unsteady and non-axisymmetrically wavy. The velocity vector fields obtained also show the same flow features found in the experiments of Wereley and Lueptow.

수직관에서 상승하는 Taylor 기포의 수치해석 (Numerical Simulation of a Taylor Bubble Rising in a Vertical Tube)

  • 손기헌
    • 대한기계학회논문집B
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    • 제25권3호
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    • pp.373-380
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    • 2001
  • In this study, a single Taylor bubble and a train of Taylor bubbles rising in a vertical tube were simulated numerically. A finite difference method was used to solve the mass and momentum equations for the liquid-gas region. The liquid-gas interface was captured by a level set function which is defined a signed distance from the interface. For a train of Taylor bubbles repeated periodically in space, the periodic conditions were imposed at the boundaries normal to the gravitational direction and the pressure boundary conditions were iteratively determined so that the computed flow rate should be equal to a given flow rate. Based on the numerical simulation, the calculated shape and rise velocity of a Taylor bubble were found to be in good agreement with the experimental data reported in the literature.

Absolute-Value-GARCH 모형을 이용한 국내 금융시계열의 Taylor 성질에 대한 사례연구 (Evidence of Taylor Property in Absolute-Value-GARCH Processes for Korean Financial Time Series)

  • 백지선;황선영;최문선
    • 응용통계연구
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    • 제23권1호
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    • pp.49-61
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    • 2010
  • 금융시계열 변동성의 의존성(dependency)은 멱변환된 절대수익률의 자기상관함수를 이용하여 측정할 수 있다. 이때, 절대수익률의 자기상관이 제곱수익률의 자기상관보다 더 강하게 나타나는 성질을 Taylor 성질이라고 한다. 본 논문에서는 여러 가지 국내 금융시계열 자료에 대하여 absolute-value GARCH(1,1)(AVGARCH(1,1)) 모형을 적합하고, Haas (2009)가 제안한 방법을 이용하여 Taylor 성질의 존재여부에 대하여 살펴보았다.

슬릿이 있는 Taylor-Couette 유동의 실험적 연구 (Experimental study of axial slit wall effect on Taylor-Couette flow)

  • 이상혁;김형범
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회B
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    • pp.3183-3186
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    • 2007
  • Taylor-Couette flow may appear when the angular velocity is different between two concentric rotating cylinders. This kind of Taylor-vortex flow can be easily seen in lots of engineering problems. In general the geometries of rotating cylinders are generally complex in these cases. In this study, we investigated Taylor-Couette flow when the outer cylinder has the slit along the annulus. The radius ratio and aspect ratio of the experimental model used was 0.825 and 48, respectively. The depth of slits is 5mm and total 18 slits are azimuthally located along the inner wall of outer cylinder. We used PIV method to measure the flow and applied index matching method to resolve the complex geometry effect. The results show the model with slit has no stable wavy vortex region above Re=143.

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축방향 홈이 있는 Taylor-Couette 유동의 실험적 연구 (Experimental Study of Axial Slit Wall Effect on Taylor-Couette Flow)

  • 이상혁;김형범
    • 대한기계학회논문집B
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    • 제31권10호
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    • pp.889-894
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    • 2007
  • The effect of the axial slit of outer cylinder on Taylor-Couette flow was experimentally investigated. The radius ratio and aspect ratio of the model was 0.825 and 48, respectively. The depth of slits was 5mm and total 18 slits were azimuthally located along the inner wall of outer cylinder. We used PIV method to measure the flow field and applied refractive index matching method to resolve the image distortion due to the complex model geometry. The results showed the axial slit did not affect the transition from laminar Couette flow to Taylor vortex. The effect of slit wall appeared when the Reynolds number is larger than Re=143 and the slit model shows the transition to turbulent Taylor vortex flow above Re=143.

TAYLOR의 아성은 더 이상 없다 - 세아이엔씨, ICIS소프트아이스크림기 -

  • 한국자동판매기공업협회
    • 벤딩인더스트리
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    • 제3권2호통권10호
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    • pp.80-81
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    • 2004
  • 소프트아이스크림기 내수시장은 그간 해외제품이 $80\%$ 이상을 점유했다. 타품목보다 국산제품을 통한 수입 대체효과가 지극히 느렸던 이유는 바로 제품 품질문제에 있었다. 소프트아이스크림기가 워낙 고성능, 고품질이어야 하다 보니 국내 제품이 해외제품의 기술력을 따라가기 힘들었던 게 그간의 현실이었다. 특히 미국 TAYLOR사의 제품은 이 시장에 절대강자의 위치를 점하고 있어 난공불락의 아성을 공고히 했다. 그런데 최근 TAYLOR 제품에 견줄만한 고품질의 국산 제품이 등장했다. 냉동기기 전문업체 세아이엔씨는 TAYLOR 제품을 타킷으로 해 심혈을 기울여 개발한 ICES 소프트아이스크림기를 선보였다. 뛰어난 성능과 경쟁력 있는 가격으로 TAYLOR의 아성에 일대 도전장을 던진 ICES 소프트아이스크림기를 집중취재했다.

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