• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.170-177
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• 2000

The Main objective of the study is to find out the basic running condition of KNR EMUs since the results can be useful in designing new EMUs. We had investigated the average annual mileages and decrepit levels. After that, we performed stress analysis for the carbody when uniformly distributed vortical loads due to the weight of the car body and passengers were applied to the underframes, in order to find out the most critical sections of the underframes and the effect of corrosion on the underframe strength.. Upon performing stress analysis, we carried out running tests of EMUs on the conventional line to measure dynamic stresses applied to the underframes.

• Smart Structures and Systems
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• 제20권5호
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• pp.539-548
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• 2017

Thermoelasticity is a contactless technique for measuring stress distributions in structural elements stressed by dynamic loads. This work describes the characteristics, analyzes the main causes of uncertainty and illustrates a series of operative methods for reducing its effects. More specifically, the effects of the angle of view between the thermographic camera and the surface of the object are studied, along with those due to the heat transmission by conduction between the various parts of the thing being measured as a function of the stress frequencies. The analyses, both theoretical and experimental, are aimed at defining the operational limits and optimal measurement and test conditions in relation to the measurement uncertainty that is considered tolerable in the specific application.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.289-292
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• 2007

The flyback converter is one of the most attractive isolated converters in small power applications because of its simple structure. However, it suffers from high device stress, large transformer size, and high voltage stress across switch and diode. To solve these problems a new cost-effective PWM single-switch isolated converter is proposed. The proposed converter has no output filter inductor, reduced voltage stress on the secondary devices, and reduced transformer size. Moreover, the switch turnoff loss is reduced and no dissipative snubber across the secondary diode is required. Therefore, it features a simple structure, low cost, and high efficiency. The operational principle and characteristics of proposed converter are presented compared with flyback converter and verified experimentally.

• Journal of Power Electronics
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• 제3권4호
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• pp.215-223
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• 2003

In this paper, a new zero-current-transition (ZCT) circuit cell is proposed. The main switch is turned-off under the zero current and zero voltage condition, and there is no additional current stress and voltage stress in the main switch and the main diode, respectively. The auxiliary switch is turned-off under the zero voltage condition, and the main diode is turned-on under the zero voltage condition. The resonant current required to obtain the ZCT condition is relatively small and regenerated to the input voltage source. The operational principles of a boost converter integrated with the proposed ZCT circuit cell are analyzed and verified by the simulation and experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1380-1382
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• 2005

The multi-resonant converter minimizes a parasitic oscillation by using the resonant tank circuit absorbed parasitic reactance existing in a converter circuit. So it is possible that the converter operated at a high frequency has a high efficiency because the losses are reduced. However, the resonant voltage stress across a switch is four or five times a input voltage. This high voltage stress increases the conduction loss. In this paper, we proposed the AT flyback multi-resonant converter. The proposed converter can reduce the voltage stress to two or three times by using two series input capacitors. The operational principle of the proposed converter was verified through the experimental converter.

• 조명전기설비학회논문지
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• 제14권3호
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• pp.6-14
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• 2000

고효율 다중공진형 컨버터는 스위칭 손질을 다중공진 회로를 이용하여 감소시킬 수 있기 때운에 고주파에서 동작이 가능하다. 이려한 고주파 스위칭 동작은 컨버터에 높은 전력 밀도를 제공한다. 그러나 공진 스위치애 걸리는 전압 스트레스는 입력전압의 4~5배 정도여서, 높은 정격의 소자를 필요로 하기 때문에 소자의 온-저항으로 인한 전도 손실을 증가시킨다. 본 문에서는 이러한 문제점 해결하기 위해 제안했던 전압 스트레스를 줄일 수 있는 AT 포워드 MRC는 모델링 해석파 이를 이용한 등가 모드 해석을 하였다. AT 포워드 MRC는 2개의 다중 공전 스위치의 동작 순서에 따라 8개의 등가 모델링이 가능하다. 이 컨버터의 동작 원리는 입력 48[V], 출력 5[V]/50[W]의 실험세트와 PSpice 시뮬레이션을 통해 확인되었으며, 측정된 최대 전압 스트레스는 입력전압의 2.9 배인 170[V]였고 최대 효율은 81.66i%로 측정되었다.

• 한국산업융합학회 논문집
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• 제20권5호
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• pp.405-410
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• 2017

This paper deals with 3D simulation of industrial robot for automated manufacturing system. In order to evaluate the operational characteristics of the industrial robot system in the worst case motion scenario, flexible - rigid multibody analysis was performed. Then, the rigid body dynamics analysis was performed and the results were compared with the flexible - rigid multibody analysis. Modal analysis was also performed to confirm the dynamic characteristics of the robot system. In the case of the flexible-rigid multibody simulation, only the structural members of interest were modeled as elastic bodies to confirm the stress state. The remaining structural members were modeled as rigid bodies to reduce computer resources.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2015년도 춘계학술대회
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• pp.338-339
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• 2015

VTS 의사결정지원시스템은 관제사들이 선박을 관제함에 있어서, 의사결정을 지원하기 위하여 선박 간 거리 등의 정보를 제공하는 시스템을 의미한다. 본 논문에서는 현재 제정되고 있는 IALA 표준을 중심으로 VTS 의사결정지원 시스템의 구분, 제공하는 경고 정보의 세분화된 정의, 제공되어야 할 경고 기능 등을 분석한다.

• 한국물환경학회지
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• 제24권4호
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• pp.458-464
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• 2008

Bulking phenomena and scum formation are common problem in suspended growth system like the activated sludge plants for wastewater treatment. Apart from wastewater composition, operating conditions, such as mechanical stress by insufficient oxygen supply, are often decisive for the occurrence of a bulking or scumming problem. There were the comparative aeration tanks in terms of sludge bulking caused by the difference of mechanical aeration facilities in the wastewater treatment plant of N paper mill company. In this study the cause of bulking was investigated through not only the biological isolation and identification but also a series of operational data consideration. On the basis of the investigation results for bulking cause, the operational criteria on dissolved oxygen concentration was derived to decrease the bulking problem.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.293-296
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• 2008

Injection molding operation consists of filling, packing, and cooling phase. The highest pressure is involved during the packing phase among the operation phases. Cavity pressure depends upon velocity to pressure switchover time and magnitude of packing pressure. The cavity pressure is directly related to stress concentration in the cavity of mold. Thus the observation and control of cavity pressure is very important to prevent mold cracking. In this study, cavity pressures were observed for operational conditions using the commercial CAE software, Moldflow. Operational conditions were velocity to pressure switchover time and packing pressure. Cavity pressures were also measured directly during injection molding. Simulation and experimental results showed good agreement.