• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.518-522
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• 2014

This paper is concerned with the dynamic modeling of transmission line undergoing galloping vibrations. To this end, the kinetic and potential energies of a uniform wire vibrating in space are derived. The equations of motion suitable for numerical simulations are derived using the assumed mode method and Lagrange equation. The resulting equations of motion are expressed in matrix form. To cope with bundled transmission line, the spacer was modelled by a spring element. As a numerical example, a two-wire transmission line combined by spacers was considered. Natural vibration characteristics show that the in-plane vibrations of the transmission line appeared in low frequency range, which may lead to galloping.

• 대한기계학회논문집A
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• 제26권5호
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• pp.843-850
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• 2002

This paper presents a simulation method using the transmission line modeling to reduce simulation runtime of hydraulic control systems. This method is based on separating the system components each other using the transmission line elements prior to simulation, which leads to divide the simulated system into several subsystems suitable for an even more efficient integration. It can also handle nonlinearities and discontinuities without flag signal when restarting integration. By applying variable integration timestep to parallel hydraulic circuits via parallel processing, it is shown that simulation run-time can be reduced significantly compared with that of Runge Kutta method.

• 전기학회논문지
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• 제62권12호
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• pp.1725-1729
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• 2013

In this paper, the modeling and simulation of infrared absorption in an infrared absorbing structure with the cascaded transmission line model were carried out. Each layer in the infrared absorbing structure can be modeled as a characteristic impedance of the cascaded transmission line model. The simulation results show that the cavity thickness to get a maximum absorption should be less than a quarter wavelength, which is somewhat different from prevalent thickness. It can be assured that the sheet resistance of an absorbing layer to get a maximum absorption is $377{\Omega}/{\square}$, that the thickness of the absorbing layer dose not affect the spectral characteristics of absorption. It is also shown that the thickness of the active layer is not critical to the IR absorption. It can also be assured that the validation of this modeling is proved in comparison with the previous results from similar absorbing structures.

• 유공압시스템학회논문집
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• 제1권2호
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• pp.20-25
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• 2004

In this study, a position control characteristics of pneumatic cylinder with transmission line is analyzed. Dynamic characteristics of transmission line using compressible fluid is changed by the flowing stiles of the fluid the diameter and the length of the line. But, the effect of the change of dynamic characteristics of transmission line by the flowing states on the position control characteristics can be neglected because of the friction force of the pneumatic cylinder. So, We assume that the position control characteristics is affected by the diameter and length of the transmission line. The experimental results according to the change of parameter of the transmission line show that the relation between the parameter of the transmission line and the position control characteristics of pneumatic cylinder driving system with the transmission line.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.446-448
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• 2000

This paper discribes the modeling and transient analysis of cable in combined transmission line under high impedance fault(HIF). And also, transient characterstic analyzed on cable covering protection unit(CCPU) is presented. Modeling of the combined transmission line is established in PSCAD/EMTDC V3. The required data to analyze the transient phenomena is given from the actual system. The results show the HIF modeling in cable, fault current according to the value of fault resistance. And also when the value and method of grounding resistance is changed in CCPU, simulation results are presented.

• 한국정보통신학회논문지
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• 제16권8호
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• pp.1599-1605
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• 2012

본 연구에서는 해저의 반사면이나 흡음재와 같이 주파수에 따라 다른 특성을 가지는 매체를 시간영역에서 수치적으로 모델링하고자 시간 해석 기법의 하나인 전달선로행렬법을 이용하였다. 기존의 흡음재의 해석에 응용되던 감쇠를 이용하는 방법의 대안으로 유한임펄스응답 필터를 전달선로행렬법에 도입하였다. 7개의 탭을 가진 FIR 필터로 구현하였으며, 시간 지연, 저역통과필터, 고역통과필터의 시뮬레이션 결과를 이론치와 비교하였다. 여러 시뮬레이션 결과를 통해 흡음재의 주파수에 따른 흡음 특성을 유한임펄스응답 필터를 고려한 하나의 요소만으로 모델링하는 것이 가능하다는 것을 확인할 수 있었다.

• Journal of Electrical Engineering and Technology
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• 제11권4호
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• pp.943-950
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• 2016

In this paper, we propose to analyze the physical characteristics of a planar dual-composite right-left handed transmission line by a common application of Bond Graph approach and Scattering formalism (Methodology S.BG). The technique, we propose consists, on the one hand, of modeling of a dual composite right-left metamaterial transmission line (D-CRLH-TL) by Bond Graph approach, and, it consists of extracting the equivalent circuit of this studied structure. On the other hand, it consists to exploiting the scattering parameters (Scattering matrix) of the DCRLH-TL using the methodology which we previously developed since 2009. Finally, the validation of the proposed and used technique is carried out by comparisons between the simulations results with ADS and Maple (or MatLab).

• 대한기계학회논문집A
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• 제30권6호
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• pp.631-636
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• 2006

In this study, a model of pneumatic cylinder position control system considering dynamic characteristics of transmission line is proposed. The transfer characteristics of transmission line are assumed to be second order transfer function because the effect of resonance characteristics of transmission line under high frequency range can be neglected by the friction force and low pass characteristics of the pneumatic cylinder driving system. Therefore, the position control system including transmission line can be modeled by using a model of pneumatic cylinder driving system and the model of transmission line. The effectiveness of the proposed model is proved by comparison of simulation results using proposed model with experimental results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.731-736
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• 2004

In this study, a linearized model of pneumatic cylinder position control system including transmission line is proposed. The transmission line using compressible fluid has a nonlinear transfer characteristics because that the frequency response of it is changed by the flowing state of the fluid. But, when the pressure difference between both sides of transmission line is low, the effect of resonance characteristics of it under high frequency range can be neglected because of the friction force and low pass characteristics of the position control system. Therefore, the transmission line can be modeled by second order transfer function and the natural frequency, damping ratio and gain are changed by the diameter and length of it. The effectiveness of the proposed model is proved by comparison of simulation results using proposed model with experimental results and simulation results using conventional model.

• Wind and Structures
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• 제31권6호
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• pp.509-522
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• 2020

Wind load is the principal cause for a large number of the collapse of transmission lines around the world. The transmission line is traditionally designed for wind load according to a linear equivalent method, in which dynamic effects of wind are not appropriately included. Therefore, in the present study, incremental dynamic analysis is utilized to investigate the stability behavior of a 400 kV transmission line under wind load. In that case, the effects of vibration of cables and aerodynamic damping of cables were considered on the stability behavior of the transmission line. Superposition of the harmonic waves method was used to calculate the wind load. The corresponding wind speed to the beginning of the transmission line collapse was determined by incremental dynamic analysis. Also, the effect of the yawed wind was studied to determine the critical attack angle by the incremental dynamic method. The results show the collapse mechanisms of the transmission line and the maximum supportable wind speed, which is predicted 6m/s less than the design wind speed of the studied transmission line. Based on the numerical modeling results, a retrofitting method has been proposed to prevent failure of the tower members under design wind speed.