• 대한기계학회논문집A
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• 제21권10호
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• pp.1636-1647
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• 1997

As most of today's automatic transmissions in passenger car adopt a electro-hydraulic control system, the role of electronically controlled solenoid valves occupies an important position and it is essential to predict solenoid transient characteristics in order to design and evaluate the performance of the hydraulic control system. However, in general, both the magnetic and electrical parameters f the solenoid system are hardly known and it is not easy to model this section with moderate complexity although mechanical system could be developed using the classical second order system. This paper presents a dynamic modelling technique of a solenoid valve, that is controlled by pulse width modulation for an automatic transmission, in terms of system identification theory. In nonlinear computer simulation, it is shown that the identified systems which produce magnetic force to input duty cycle for various excitation signals predict the static and dynamic performance very well near the operating point and in experiment conducted to confirm the validity of identification theory for PWM solenoid valve, we find that there is a good agreement between the experimental data and simulation result. Hence, this model can be utilized in the development of pressure control system with PWM solenoid valve.

• 한국전자파학회논문지
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• 제19권8호
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• pp.832-836
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• 2008

본 연구에서는 무한 도체판의 좁은 슬릿에 TM 편파된 평면파가 입사되는 경우의 전자기적 결합 문제를 고려 하였다. 등가 회로를 이용하여 공진된 슬릿을 통한 최대 전력 투과 메커니즘을 설명하는데 연구의 주안점을 두었다. 슬릿이 공진되었을 때 좁은 슬릿을 통해 투과된 전력은 슬릿 폭에 무관하게 유효 슬릿 폭 1/pi 파장에 도달되는 전력과 동일함을 보였다. 제안된 구조와 두꺼운 도체 스크린에서의 좁은 슬릿을 통한 최대 전력 투과 현상들의 유사성을 등가 회로의 관점에서 기술하였다. 또한, 공진이 일어났을 때 슬릿에 의한 산란 전력과 슬릿을 통한 투과 전력이 동일함을 확인하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.639-640
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• 2008

• 전자공학회논문지A
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• 제33A권7호
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• pp.15-22
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• 1996

In the soliton transmission system for a long-length and high bit rate data transmission systme using the nonlinear/dispersive optical fibers, the improtant problem is the loss characteristics and is the limited transmission rate by interaction forces. In this paper, It is explained the reasons of moved time position for the soliton peak value due to interaction force sof adjacent solitons. And for the analysis of interaction force affection level in the losslessmedia, we define the percent parameter of error rate due to the interaction forces and propose the optimum time distance of adjacent solitons by peak value tracking methods. With the results, initial percent of error is approximately 50% when itme difference between adjacent solitons is 5 times of funddametnal soliton pulse width. And it is confirmed that maximum transmission length of th esolitons is approximately 38 times of fundamental soliton period, which the maximum allowable percoent of error is 50%.

• 한국통신학회논문지
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• 제28권4A호
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• pp.232-237
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• 2003

이 논문에서는 부하가 걸려 있는 전송 선로의 길이가 변화할 경우 입력반사 계수가 스미스차트 상에서 그리는 쾌적의 방정식을 유도한다. 결과에 따르면, 전송 선로의 특성 임피던스가 정규화 임피던스와 다를 경우 쾌적은 원을 그리게 되며, 그 원의 중심과 반지름은 부하의 임피던스와 전송 선로의 특성 임피던스에 의해 결정된다. 이 결과는 마이크로스트립 선로를 사용하여 정합 회롤를 설계할 때 선로의 길이와 너비를 조정할 필요가 있을 경우 유용하게 사용될 수 있다.

• 한국해양공학회지
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• 제20권6호
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• pp.82-87
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• 2006

Numerical analysis is performed on the wave transmission coefficient of various crown widths of the double-submerged breakwater and the triple-submerged breakwater, varying the distance between submerged breakwaters. The finite element method is used, and the fluid motion is considered as linearized two-dimensional potential flow. In case of the double- and triple-submerged breakwaters, as the width of submerged breakwater increases, the minimum wave transmission coefficient decreases and the wave period at which the minimum wave transmission coefficient occurs moves to a longer wave period the distance between submerged breakwaters at which the minimum wave transmission coefficient occurs becomes larger.

• Journal of Power Electronics
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• 제19권2호
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• pp.602-611
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• 2019

The major drawbacks of magnetic resonant coupled wireless power transfer (WPT) to the embedded sensors on spindles are transmission instability and low efficiency of the transmission. This paper proposes a novel double-loop coil design for wirelessly charging embedded sensors. Theoretical and finite-element analyses show that the proposed coil has good transmission performance. In addition, the power transmission capability of the double-loop coil can be improved by reducing the radius difference and width difference of the transmitter and receiver. It has been demonstrated by analysis and practical experiments that a magnetic resonant coupled WPT system using the double-loop coil can provide a stable and efficient power transmission to embedded sensors.

• 한국해안해양공학회지
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• 제16권4
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• pp.206-212
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• 2004

본 연구에서는 폭이 좁은 1열 및 다열 잠제 대한 파랑 차단 성능을 폭이 넓은 1열 및 2열 잠제의 파랑 차단 성능과 비교$.$연구하였다. 파동장은 선형포텐셜 이론으로 모형화 하였으며 유한요소법을 적용하여 수치해석 하였다. 수치해석 결과, 1열 잠제에서는 폭이 좁은 잠제가 폭이 넓은 잠제보다 파랑 차단 성능이 다소 떨어지나 어느 정도 효과적인 파랑 차단 성능을 보여주고 있으며, 폭이 좁은 잠제를 2열 또는 3열로 배치하였을 때에는 폭이 넓은 1열 또는 2열 잠제보다 훨씬 뛰어난 파랑 차단 성능을 보이고 있다.

• Tribology and Lubricants
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• 제36권2호
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• pp.96-104
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• 2020

The electric vehicle industry is rapidly developing because of enforced environmental regulations, and several studies have been conducted on the multispeed transmission to improve the fuel efficiency of electric vehicles. Among these studies, research on the power density improvement of electric vehicle transmission is critical. Thus, the optimal design of the gear train is necessary to enhance transmission efficiency. In this study, an optimal design methodology for the lightweight two-speed transmission of electric vehicles is proposed. Because a multispeed transmission has many operating conditions and equality and inequality constraints, a new gear design method that combines analytical and iterative methods is applied without using complex optimization algorithms. Sets of possible design variables are generated considering the operating conditions and various design variables. The modules and face width ratios of each stage gear that satisfy the corresponding operating conditions are analytically calculated. The volume of the gear train is calculated, evaluated, and arranged using these values to determine the optimal solution for minimizing the volume, and the proposed methodology is applied to the actual model to verify its effectiveness. The design of a two-speed transmission with multiple operating conditions and constraints without complicated optimization algorithms can be optimized.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.267-270
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• 2005

An RFID patch antenna for metallic object has been designed. The effects of variation of distance between the tag antenna and ground of the antenna have been studied. Various dielectric constants, thickness, permittivity, width of transmission line and length of transmission line have been used to design the better tag antenna for metallic object.