• Title, Summary, Keyword: transfer function

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Necessary and Sufficient Conditions for Characteristic Transfer Function Matrices

  • Eisaka, Toshio
    • Proceedings of the IEEK Conference
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    • pp.1875-1877
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    • 2002
  • There exist several forms of transfer function descriptions for multivariable LTI systems. We treat transfer function matrix with characteristic polynomial as its common denominator named Characteristic Transfer-function Matrices (CTM). First, we clarify necessary and sufficient conditions of CTM, then, we show some related lemmas. These interpretations not only offer deeper explanations but they also provide ways for calculations of all possible transfer matrices, system zeros, and inverse polynomial matrices.

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Non-Equilibrium Green Function Method in Spin Transfer Torque

  • You, Chun-Yeol
    • Journal of Magnetics
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    • v.12 no.2
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    • pp.72-76
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    • 2007
  • We investigate the spin transfer torque in metallic multilayer system by employing Keldysh non-equilibrium Green function method. We study the dependences of the spin transfer torque on the detailed energy configuration of ferromagnetic, spacer, and lead layers. With Keldysh non-equilibrium Green function method applied to a single band model, we explore spin transfer torque effect in various layer structures and for various material parameters.

The Development of Equivalent System Technique for Deriving an Energy Function Reflecting Transfer Conductances (선로저항을 반영하는 에너지함수 유도를 위한 등가시스템 기법의 개발)

  • Moon, Young-Hyun;Cho, Byoung-Hoon;Roh, Tae-Hoon;Choi, Byoung-Kon
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.10
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    • pp.1175-1182
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    • 1999
  • This paper shows that a well-defined energy function can be developed to reflect the transfer conductances for multi-machine power systems under an assumption that all transmission lines have uniform R/X rations. The energy function is derived by introducing a pure reactive equivalent system for the given system. In this study, a static energy function reflecting transfer conductances is also derived as well as the transient energy function. The proposed static energy function is applied to voltage stability analysis and tested for various sample systems. The test results show that the accuracy of voltage stability analysis can be considerable improved by reflecting transfer conductances into the energy function.

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An evolutionary algorithm for optimal damper placement to minimize interstorey-drift transfer function in shear building

  • Fujita, Kohei;Yamamoto, Kaoru;Takewaki, Izuru
    • Earthquakes and Structures
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    • v.1 no.3
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    • pp.289-306
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    • 2010
  • A gradient-based evolutionary optimization methodology is presented for finding the optimal design of viscous dampers to minimize an objective function defined for a linear multi-storey structure. The maximum value along height of the transfer function amplitudes for the interstorey drifts is taken as the objective function. Since the ground motion includes various uncertainties, the optimal damper placement may be different depending on the ground motion used for design. Furthermore, the transfer function treated as the objective function depends on the properties of structural parameters and added dampers. This implies that a more robust damper design is desired. A reliable and robust damping design system against any unpredictable ground motions can be provided by minimizing the maximum transfer function. Such design system is proposed in this paper.

Approximation of Pulse Transfer Function of Impulse Response Data (임펄스응답 데이타의 펄스전달함수의 근사)

  • Lee, Dong-Cheol;Bae, Jong-Il;Chung, Hyeng-Hwan
    • Proceedings of the KIEE Conference
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    • pp.683-685
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    • 1999
  • As a method of obtaining pulse transfer function. transfer function of discrete-time from input-output data, there are method of obtaining unknown parameter of pulse transfer function from estimated impulse response before(1-3). There is no need to approximate to several meanings because of not being established algebraical relations between impulse response for estimation error and parameter of transfer function exactly. In this paper, I inquire the method[4] of obtaining the optimal pulse transfer function as a meaning of Hankel norm approximation from impulse response data and examine estimated property as computer simulation from this method.

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A Study on the Induction Method of Transfer Function of Bond Graph using Mason's Rule (메이슨의 공식을 이용한 본드그래프의 전달함수 유도법에 관한 연구)

  • 한창수;오재응
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.4
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    • pp.66-75
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    • 1998
  • In many case of optimal design and sensitivity analysis, obtaining of transfer function between input and output variables is a difficult and time-consuming problem. The bond graph modeling is a method that is used for making it easy to analyze complex systems composed of mechanical and electrical parts. It gives us a simple and systematic tool to get state-space equations easily. And we can obtain the transfer function graphically using bond graph and Mason's rule. This paper shows how bond graphs are converted to block diagram and how Mason's rule is applied. And the simple direct method to obtain transfer function from bond graph is introduced. As a example, induction of transfer function of electric power steering composed of mechanical and electrical parts will be done.

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Forecasting of Dissolved Oxygen at Kongju Station using a Transfer Function Noise Model (전이함수잡음모형에 의한 공주지점의 용존산소 예측)

  • 류병로;조정석;한양수
    • Journal of Environmental Science International
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    • v.8 no.3
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    • pp.349-354
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    • 1999
  • The transfer function was introduced to establish the prediction method for the DO concentration at the intaking point of Kongju Water Works System. In the mose cases we analyze a single time series without explicitly using information contained in the related time series. In many forecasting situations, other events will systematically influence the series to be forecasted(the dependent variables), and therefore, there is need to go beyond a univariate forecasting model. Thus, we must bulid a forecasting model that incorporates more than one time series and introduces explicitly the dynamic characteristics of the system. Such a model is called a multiple time series model or transfer function model. The purpose of this study is to develop the stochastic stream water quality model for the intaking station of Kongju city waterworks in Keum river system. The performance of the multiplicative ARIMA model and the transfer function noise model were examined through comparisons between the historical and generated monthly dissolved oxygen series. The result reveal that the transfer function noise model lead to the improved accuracy.

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Estimation of Pump Induced Vibration Force Using Transfer Function (전달함수를 이용한 펌프(50Hp)의 진동가진력 산정)

  • 노병철
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.157-162
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    • 1998
  • Dynamic loads may arise from rotating parte of pump if they are insufficiently balanced. The magnitude of pump induced vibrations varies according to the weight, eccentricity, and unbalanced mass of pump. This is a study to estimate the pump induced vibration in time and frequency domain by transfer function. The transfer function has real and imaginary information of signals, and response function has also real and imaginary information. So the vibration force can be obtained from the response and transfer function by complex calculation. The amplitudes and components of 50Hp pump vibration force are suggested.

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An Efficient Design Technique for the Flattened Transfer Function of Arrayed Waveguide Grating

  • Jung Jae-Hoon;Moon Hyung-Myung;Kwak Seung-Chan
    • Journal of the Optical Society of Korea
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    • v.10 no.1
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    • pp.33-36
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    • 2006
  • This paper describes an efficient optimal design method for an arrayed waveguide grating (AWG) with flattened transfer function. The objective function is the norm of the difference between calculated and target spectra. To analyze the AWG transfer function, the Fresnel-Kirchhof diffraction formula was employed and the design variable was optical path difference of each array waveguide. The (1+1) Evolution Strategy was applied to an eight-channel coarse wavelength division multiplexing (CWDM) AWG as the optimization tool. The optimized transfer function will considerably improve the system performance.

Introduction to Combustion Instability Modeling Using Flame Transfer Function (화염전달함수를 이용한 연소불안정 모델링 기법 소개)

  • Kim, Daesik
    • 한국연소학회:학술대회논문집
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    • pp.71-72
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    • 2014
  • The current paper introduce the flame transfer function calculation results using CFD in order to quantify the heat release fluctuations in a lean premixed gas turbine combustor. Comparisons of the modeled and measured flame shapes were made using the optimized heat transfer conditions.

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