• 한국정밀공학회지
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• 제19권5호
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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.

• International Journal of Precision Engineering and Manufacturing
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• 제4권2호
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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.

• 한국정밀공학회지
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• 제12권5호
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• pp.126-135
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• 1995

An exhaust muffler is one of the simple and effective means to meet the demand for a quiet vehicle, and it deserves a close attention to effectively reduce the engine noise. The transfer function technique is one of the tools that have been used to analyze the noise characteristics of the exhaust muffler. In this paper we obtained a transfer function using the forward-going and backward-going components of sound pressure in the exhaust muffler, which is compatible wiht lattice filter algorithm. This form of transfer function is obtained for the basic elements of a muffler, such as uniform tube, open termin- ation, closed termination, anechoic termination, expansion, contraction, extended-tube resonator, hole, Helmholtz resonator, and concentric hole-cavity resonator. The results are combined to produce the transfer function of various types of mufflers. With this transfer function we calculate the transmission and insertion losses of mufflers, and examined the effects of various design parameters. Comparisons were made between the calculation and experimental results, which showed a good agreement, and we conclude that the transfer function of lattice form can be used to analyze the noise characteristics of the exhaust mufflers.

• 대한조선학회논문집
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• 제47권6호
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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.

• 상하수도학회지
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• 제10권2호
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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.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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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.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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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.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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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.

• 대한전자공학회논문지SD
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• 제45권4호
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• pp.146-153
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• 2008

High speed serial link에 적합한 clock multiphase generator용 integrated phase-locked loop (PLL)을 설계하였다. 설계된 PLL은 programmable current mirror를 사용하여 동작 범위 안에서 동일한 loop bandwidth와 damping factor를 가진다. 또한 설계한 PLL 회로 netlists를 가지고 HSPICE 시뮬레이션을 통해 close-loop transfer function과 VCO의 phase noise transfer function을 구하였다. Board 위 칩의 자체 임피던스는 decoupling capacitor의 크기와 위치에 따라 계산된다. 세부적으로, close-loop transfer function에서 gain의 최대값과 VCO noise transfer function에서 gain의 최대값 사이의 주파수범위에서 decoupling capacitor의 크기와 위치에 따른 보드 위 칩의 자체 임피던스를 구하였다. 이를 바탕으로 보드에서의 decoupling capacitor의 크기와 위치가 PLL의 jitter에 어떠한 영향을 미치는지 분석하였다. 설계된 PLL은 1.8V의 동작 전압에서 400MHz에서 2GH의 wide operation range를 가지며 $0.18-{\mu}m$ EMOS공정으로 설계하였다. Reference clock은 100MHz이며 전체 PLL power consumption은 1.2GHz에서 17.28 mW이다.