• Journal of applied mathematics & informatics
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• 제28권1_2호
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• pp.49-58
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• 2010

In the present article we consider the diffusive Nicholson's blowflies equation with nonlocal delay incorporated into an integral convolution over all the past time and the whole infinite spatial domain $\mathbb{R}$. When the kernel function takes a special function, we construct a pair of lower and upper solutions of the corresponding travelling wave equation and obtain the existence of travelling fronts according to the existence result of travelling wave front solutions for reaction diffusion systems with nonlocal delays developed by Wang, Li and Ruan (J. Differential Equations, 222(2006), 185-232).

• 호남수학학술지
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• 제33권2호
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• pp.247-259
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• 2011

In this paper, the $(\frac{G'}{G})$-expansion method is used to construct new exact travelling wave solutions of some nonlinear evolution equations. The travelling wave solutions in general form are expressed by the hyperbolic functions, the trigonometric functions and the rational functions, as a result many previously known solitary waves are recovered as special cases. The $(\frac{G'}{G})$-expansion method is direct, concise, and effective, and can be applied to man other nonlinear evolution equations arising in mathematical physics.

• 한국구조물진단유지관리공학회 논문집
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• 제12권1호
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• pp.167-174
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• 2008

최근 국내에서 장대교량의 건설이 증가함에 따라 그에 대한 내진설계의 중요성도 증대되고 있다. 이와같은 여건을 반영하여 새로 개정된 케이블 강교량 설계지침(안)의 내진설계편에서 지진파의 파동전달효과와 지반특성효과를 일부 반영하였다. 본 연구에서는 국내 설계규정에 따라 사장교(주경간500m)의 다양한(균등입력, 파동전달효과, 파동전달효과+지반특성효과) 지진응답해석을 수행하여 설계적용시 문제점에 대하여 검토해 본 결과 장대교의 파동전달효과는 지지점간 거리가 짧은 경우에도 지반이 연약한 경우 큰 영향을 받는 것으로 나타났다. 한편 지반의 종류에 상관없이 파동전달효과와 함께 지점별로 지반특성을 고려한 해석이 그렇지 않은 해석결과보다 큰 값이 산출되었다. 따라서 장대교의 지진응답해석시 파동전달효과 및 지반특성효과의 적용에 대한 세심한 고려가 필요한 것으로 판단된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1972-1974
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• 2000

In this paper, we made an experiment on fault location of underground cables with travelling wave. The 5C2V coaxial cables of 100, 200m length, connected with discharge gap, are used for simplifying model cable lines of power cable. And 100KHz -2MHz CT and HV probe are installed at one side of the ends. We made travelling pulse in discharge gab and then pulse travelled along the cable to the both ends. Therefore, it is detected in CT and HV probe. Measuring the time difference of the pulse start and arrival, we were able to obtain the distance of pulse travelling. Consequently, our experimental results show the possibility to detect fault location of underground cables with travelling wave.

• 호남수학학술지
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• 제37권4호
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• pp.411-421
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• 2015

This paper investigates the issue of analytic travelling wave solutions for some important coupled models of fractional order. Analytic travelling wave solutions of the considered model are found by means of the Q-function method. The results give us that the Q-function method is very simple, reliable and effective for searching analytic exact solutions of complex nonlinear partial differential equations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.95-97
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• 1988

A method of digital transmission line protection using travelling wave is presented. It is shown that the fault current appears as a difference of two quantities associated with the travelling wave at each terminal. The phasor of these quantities are extracted and transmitted to the other end via communication channel to detect the line fault.

• 호남수학학술지
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• 제35권4호
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• pp.683-699
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• 2013

In this paper, an improved ($\frac{G^{\prime}}{G}$)-expansion method is proposed for obtaining travelling wave solutions of nonlinear evolution equations. The proposed technique called ($\frac{F}{G}$)-expansion method is more powerful than the method ($\frac{G^{\prime}}{G}$)-expansion method. The efficiency of the method is demonstrated on a variety of nonlinear partial differential equations such as KdV equation, mKd equation and Boussinesq equations. As a result, more travelling wave solutions are obtained including not only all the known solutions but also the computation burden is greatly decreased compared with the existing method. The travelling wave solutions are expressed by the hyperbolic functions and the trigonometric functions. The result reveals that the proposed method is simple and effective, and can be used for many other nonlinear evolutions equations arising in mathematical physics.

• 전기학회논문지
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• 제57권8호
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• pp.1311-1317
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• 2008

In this paper, a fault location algorithm using wavelet transform is proposed for HVDC cable lines. The arriving instants of the first and second fault-induced backward travelling waves can be detected by using wavelet transform. The fault distance is estimated by using the time difference between the two instants of backward travelling waves and the velocity of the travelling wave. To distinguish between the backward wave from fault point and the backward wave from the remote end, polarities of backward waves are used. The proposed algorithm is verified varying with fault distances and fault resistances in underground cables of VSC(voltage source converter) HVDC system and CSC(Current Source Converter) HVDC respectively. Performance evaluations of the proposed algorithm shows that it has good ability for a fault location of HVDC cable faults.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 제11회 정기총회 및 00년 동계학술발표회 논문집
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• pp.14-15
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• 2000

We study the microwave characteristics of traveling-wave photodetector using the finite-difference time-domain method. We present two parameters for design, the width of PIN region and the thickness of i-layer, and analyze TWPD's property in frequency domain.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.681-684
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• 2003

Piezoelectric motors have been successfully developed for various applications like autofocus drives in camera lenses and handling equipment for high-accuracy positioning. In this paper, the travelling-wave motor which used in the camera lense, using bending vibration of a ring was studied. The basic structure of the motor is same but we suggested a few parameters for considering their design. The parameter is different from sine and cosine region of the voltage of the ceramic surface, displacement according to the wave number difference, and the phase difference. Same size of ceramics and aluminium ring were used for the stator. As a result, the displacement is dependent on the wave number.