• Title, Summary, Keyword: transfer function

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Theoretical Verification on the Motion Error Analysis Method of Hydrostatic Bearing Tables Using a Transfer Function

  • Park, Chun-Hong;Oh, Yoon-Jin;Lee, Chan-Hong;Hong, Joon-Hee
    • International Journal of Precision Engineering and Manufacturing
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    • v.4 no.2
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    • pp.64-70
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    • 2003
  • A new method using a transfer function is introduced in the present paper for analyzing the motion errors of hydrostatic bearing tables. The relationship between film reaction force in a single-side hydrostatic pad and the form error of guide rail is derived at various spatial frequencies by finite element analysis, and it is expressed as a transfer function. This transfer function clarifies so called 'the averaging effect of an oil film' quantitively. It is found that the amplitude of film force is reduced as the spatial frequency increases or the relative width of the pocket is reduced. The motion errors of a multi pad type table are estimated using a transfer function, the form errors of a guide rail and the geometric relationship between the pads. The method is named as the Transfer Function Method (TFM). The motion errors calculated by the TFM show good agreement with the motion errors calculated by the Multi Pad Method considering the entire table as an analysis object. From the results, it is confirmed that the proposed TFM is very effective to analyze the motion errors of hydrostatic tables.

Proposal and Theoretical Verification on Motion Error Analysis Method of Hydrostatic Tables Using Transfer Function (전달함수을 이용한 유정압테이블 운동정밀도 해석법의 제안 및 이론적 검증)

  • Park, Chun-Hong;Oh, Yoon-Jin;Lee, Chan-Hong;Hong, Joon-Hee
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.5
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    • pp.56-63
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    • 2002
  • A new model utilizing a transfer function is introduced in the present paper for analizing motion errors of hydrostatic tables. Relationship between film reaction force in a single hydrostatic pad and form error of a guide rail is derived at various spacial frequencies by finite element analysis, and it is expressed as a transfer function. This transfer function clarifies so called averaging effect of the oil film quantitively. For example, it is found that the amplitide of the film reaction farce is reduced as the spacial frequency increases or relative width of the pocket is reduced. Motion errors of a multiple pad table is estimated from transfer function, geomatric relationship between each pads and form errors of a guide rail, which is named as Transfer Function Method(TFM). Calculated motion errors by TFM show good agreement with motion errors calculated by Multi Pad Method, which is considered entire table as an analysis object. From the results, it is confirmed that the proposed TFM is very effective to analyze the motion errors of hydrostatic tables.

A Short-term Forecasting of Water Supply Demands by the Transfer Function Model (Transfer Function 모형을 이용한 수도물 수요의 단기예측)

  • Lee, Jae-Joon
    • Journal of Korean Society of Water and Wastewater
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    • v.10 no.2
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    • pp.88-103
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    • 1996
  • The objective of this study is to develop stochastic and deterministic models which could be used to synthesize water application time series. Adaptive models using mulitivariate ARIMA(Transfer Function Model) are developed for daily urban water use forecasting. The model considers several variables on which water demands is dependent. The dynamic response of water demands to several factors(e.g. weekday, average temperature, minimum temperature, maximum temperature, humidity, cloudiness, rainfall) are characterized in the model by transfer functions. Daily water use data of Kumi city in 1992 are employed for model parameter estimation. Meteorological data of Seonsan station are utilized to input variables because Kumi has no records about the meteorological factor data.To determine the main factors influencing water use, autocorrelogram and cross correlogram analysis are performed. Through the identification, parameter estimation, and diagnostic checking of tentative model, final transfer function models by each month are established. The simulation output by transfer function models are compared to a historical data and shows the good agreement.

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Implementing Framework for Transfer Function-based Ship Underwater Radiated Noise Analysis (전달함수 기반의 선박 수중방사소음 해석 프레임워크 구현)

  • Kim, Kook-Hyun
    • Journal of the Society of Naval Architects of Korea
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    • v.47 no.6
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    • pp.803-807
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    • 2010
  • The transfer function method is a widely used in the analysis of underwater radiated noise of ships because it is simple to implement and gives a simple way in the design stage requiring trade-off studies on various kinds of noise sources. In this study, a framework is implemented based on the transfer function method. The framework is interfaced to a software providing transfer functions of hull force to underwater radiated noise. The transfer function-based underwater radiated noise analysis approach is reviewed and the implemented framework structure is described. As an example, a numerical calculation of a virtual ship is carried out and its results are investigated in terms of applicability to real ship design project.

Transfer function of the Frequency-Controlled Resonant Inverter (주파수 제어형 공진 인버터의 전달함수)

  • An Chan Gweon;Yun Tae Seong;Lee Ju Hyeong;Lee Chi Hwan
    • Proceedings of the KIPE Conference
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    • pp.393-396
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    • 2004
  • This paper proposed a transfer function of a frequency-controlled resonant inverter for output power control. The inverter is modeled as an equivalent circuit by using Phasor transformation. A transfer function is derived from the equivalent circuit which contains cross-coupled nonlinear parts. By simulation of the circuit, the transfer function can be approximated as a linear first-order function. The proposed transfer function is verified through comparison of experimental and simulation results.

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Compatibility Relationship of Transfer Function Parameters of Structures (구조물 전달 함수의 구성 조건 관계식에 관한 연구)

  • 채장범
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.763-767
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    • 1994
  • The measured vibration on a machine or a structure is shaped by the excitation waveform and the path transfer function. Mechanism diagnostics tends to focus on retrieving source featurce by minimzing the effects of the structural path, while in structural diagnostics we are more interested in minimizing source effects and retrieving path parameters. In structural diagnostics, therefore, there are experimental issues of gathering data that are independent source effects and finding a transfer function signature that reveals structural defects. This paper describes how the transfer function can be obtained more accurately by experiment using the compatibility relationship which is newly discovered.

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Prediction vehicle interior noise using Acoustic Transfer Function (Acoustic Transfer Function을 이용한 실차 실내 소음 예측)

  • Koh, Sung-Gyoo;Shin, Han-Seung;Cho, Whan-Chul
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.534-537
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    • 2011
  • This Paper present prediction Vehicle Interior Noise using ATF(Acoustic Transfer Function) and engine radiated sound power. This is useful tool to qualifying the effectiveness of Air-borne noise Path. Furthermore This method provide acoustic package performance of the vehicle and able to prepare frequency band to same segment or benchmarking vehicle.

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Combustion Instability Modeling for a Lean Premixed Gas Turbine Combustor using Flame Transfer Function Approach

  • Kim, Daesik;Cha, Dong-Jin
    • 한국연소학회:학술대회논문집
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    • pp.53-54
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    • 2012
  • In an IGCC plant, one of the most important issues on fuel flexibility in the lean premixed combustor is combustion instabilities. They are characterized by large amplitude pressure oscillations which are caused by unsteady heat release from the flames. The relationship between the unsteady heat release and flow oscillation can be qualitatively and quantitatively explained by flame transfer function. This paper introduces combustion instability modeling methods based on the flame transfer function approach.

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An Enhancement of Transfer Function Synthesis by Improving the Leakage Error of FRF (FRF 누설오차 개선에 의한 전달함수 합성법의 향상)

  • Ahn, Se-Jin;Jeong, Weui-Bong;Kim, Seung-Yup
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.354.2-354
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    • 2002
  • The frequency response function(FRF) of each substructure is used in the transfer function synthesis method(TFS). The dynamic characteristics of an entire system are obtained by synthesizing results of substructures. The accuracy of TFS will depend on that of FRF of each substructure. The impact hammer testing is widely used to obtain the modal characteristics of substructures. (omitted)

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Combustion Instability modeling - 1D approach (연소불안정 모델링 - 1D 접근법 기반)

  • Kim, Daesik;Yoon, Myunggon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.65-67
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    • 2017
  • Various combustion modeling approaches have been developed and verified in a combustion system such as rockets, gas turbines, and so on. This study introduces basic theory and recent research activities on 1D network model where a system is divided into a series of acoustic element and mass/momemtum/energy conservations are applied in the component. Each component is connected to the neighboring ones with proper jump conditions. Flame transfer function and acoustic transfer function are determined and effects of the each function on the system instability is investigated.

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