• Journal of KSNVE
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• v.9 no.6
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• pp.1187-1192
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• 1999

The purpose of this study is to determine the most appropriate experimental method of the measurement of "damping loss factors" (DLF) for the statistical energy analysis(SEA) calculation. The successful prediction of vibration levels from the structure is critically dependent on the accurate estimation of DLF's not only in conventional vibration analysis but especially in SEA. Unforunately, calculation of accurate DLF is not an easy matter. So experimental methods are made use of for the DLF values. Three kinds of experimental methods for estimating DLF, i.e. decay rate method, half-power bandwidth method and power balance method, are presented and tests are carried out for the plate and the cylindrical shell examples. Pro and con of each methods is reviewed. Finally, calculated DLF values are used for vibration level estimation using commercial SEA software and compared with measured vibration data.tion data.

• Journal of the Korean Solar Energy Society
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• v.31 no.5
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• pp.91-98
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• 2011

연료전지 차랑용에 있어서 공기 가습 및 감습의 중요성은 매우 크다. 특히 PEM(Proton Exchange Membrane)연료전지에서 수분평형은 총괄시스템성능에 큰 영향을 미치는 요소인데, 이에 관한 중요한 연구가 지금까지 광범위하게 수행되고 있다. 또한 차량과 같이 동적부하 연료전지를 활용하는 분야에 있어서, 전류의 흐름은 차량용 파워 부하에 크게 영향을 받는다. 따라서 전기적 흐름이 발생하면, 이에 따라 수분이 발생하게 되는데, 이러한 응축 수분은 예측이 되며, 수관리 시스템에서 이를 중요한 제어 기준으로 활용한다. 그러므로 적절한 제어방법을 선택하면 유입공기의 온도와 습도의 최적값을 얻을 수 있다. 따라서, 본 논문에서는 PEM 연료전지의 수관리를 위하여 수분전달 모델과 유전알고리즘(genetic algorithm)을 사용하는 제어방법에 초점을 두고 있다.

• Journal of Life Science
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• v.18 no.1
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• pp.30-37
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• 2008

The purpose of this study was to investigate the effect of Isotonic Training and Isotonic isometric complex Training to Knee joint Isokinetic muscle function in the high-school Taekwondo athlete. This subjects were randomly divided into two groups; a Isotonic Training group (n=7) Isotonic isometric complex Training group (n=7), Taekwondo athletes share each, 12 weeks between executes a motion. peak torque, H/Q ratio, bilateral muscular ratio muscular endurance of knee joint measured. For this study, two-way ANOVA with repeated measure were used. The result of this study presents between groups was not plain difference expressed. H/Q ratio, bilateral muscular ratio, muscular endurance was plain difference expressed after 12 weeks point of time (p>0.05) and peak torque was plain difference expressed (p<0.05). Conclusion each group did not appear all but one (peak torque), but point of view exercise was effect H/Q ratio, bilateral muscular ratio, muscular endurance, peak torque plain difference expressed.