• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
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• pp.623-628
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• 2009

There is an increasing demand for efficient high power/weight auxiliary power supplies for use on high speed traction application. Many new conversion techniques have been proposed to reduce the voltage and current stress of switching components, and the switching losses in the traditional pulse width modulation(PWM) converter. Especially, the phase shift full bridge zero voltage switching PWM techniques are thought most desirable for many applications because this topology permits all switching devices to operate under zero voltage switching(ZVS) by using circuit parasitic components such as leakage inductance of high frequency transformer and power device junction capacitance. The proposed topology is found to have higher efficiency than conventional soft-switching converter. Also it is easily applicable to phase shift full bridge converter by applying an energy recovery snubber consisted of fast recovery diodes and capacitors.

• Physical Therapy Rehabilitation Science
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• 제6권4호
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• pp.189-195
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• 2017

Objective: The purpose of this study was to examine the effects of real-time visual feedback weight shift training during golf swinging on golf performance. Design: Repeated-measures crossover design. Methods: Twenty-sixth amateur golfers were enrolled and randomly divided into two groups: The golf swing training with real-time feedback on weight shift (experimental group) swing training on the Wii balance board (WBB) by viewing the center of pressure (COP) trajectory on the WBB. All participants were assigned to the experimental group and the control group. The general golf swing training group (control group) performed on the ground. The golf performance was measured using a high-speed 3-dimensional camera sensor which analyses the shot distance, ball velocity, vertical launch angle, horizontal launch angle, back spin velocity and side spin velocity. The COP trajectory was assessed during 10 practice sessions and the mean was used. The golf performance measurement was repeated three times and its mean value was used. The assessment and training were performed at 24-hour intervals. Results: After training sessions, the change in shot distance, ball velocity, and horizontal launch angle pre- and post-training were significantly different when using the driver and iron clubs in the experimental group (p<0.05). The interaction time${\times}$group and time${\times}$club were not significant for all variables. Conclusions: In this study, real-time feedback training using real-time feedback on weight shifting improves golf shot distance and accuracy, which will be effective in increasing golf performance. In addition, it can be used as an index for golf player ability.

• 한국시뮬레이션학회논문지
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• 제16권4호
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• pp.43-55
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• 2007

생산 공정 제어방법들 중에서 이동평균 제어와 지수가중치 이동평균 제어는 가장 널리 사용되는 제어이다. 두 제어는 모두 정확한 제어식을 알고 있다는 전제 하에 최적화된 제어들이다. 이 논문에서는 제어식의 잘못된 예측으로부터 발생하는 문제점에 대해 다루었다. 추정한 모수의 정확도와 가중치 $\lambda$의 범위에 의해 결정되는 각각의 제어방식의 제어한계에 대해서 확인하고 제어 간의 성능을 평가하였다. 또한 잘못 추정된 모델이 존재하는 공정에서 Shift가 발생하였을 때 최적의 제어와 그것을 실제 공정에서 어떻게 적용할지에 대해서 연구하였다. 시뮬레이션을 통해 제안하는 방법의 효용성을 검증하였다.

• 대한한방부인과학회지
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• 제21권3호
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• pp.231-244
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• 2008

Purpose: The purpose of this study is to analyze body composition, obesity according to working pattern of working women. The subjects were workers in the automobile manufacturing industry. Methods: The subjects consisted of 514 industrial women workers who had received Korean oriental medicine health examination and submitted questionires about working pattern, during 8 months from April 2005 to November 2005. The body composition was measured by X-scan(Jawon medical, Seoul, Korea). We analyzed the relationship between body composition analysis, obesity and shift pattern with $X^2-test$ using the SPSS Ver. 12.0 Results: Regarding the realationship between body composition and working pattern, shift worker group had a significantly higher level of body weight, ratio of body fat, visceral fat and abdominal fat than normal worker. Conclusion: From this study, we can know that shift work can influence on working women's body composition and obesity.

• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1715-1721
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• 2013

Magnetic properties of magnetite ferrofluid are studied by measuring magnetic weights under different magnetic fields with a conventional electronic balance. Magnetite nanoparticles of 11 nm diameter are synthesized to make the ferrofluid. Magnetization calculated from the magnetic weight reveals the hysteresis and deviates from the Langevin function at high magnetic fields. Magnetic weight shifts instantaneously with magnetic field change by Neel and Brown mechanism. When high magnetic field is applied to the sample, slower change of magnetic weight is accompanied with the instantaneous shift via agglomeration of nanoparticles. The slow change of the magnetic weight shows the stretched exponential kinetics. The temporal change of the magnetic weight and the magnetization of the ferrofluid at high magnetic fields suggest that the superparamagnetic sample turns into superspin glass by strong magnetic interparticle interactions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1954-1957
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• 2005

A quantitative evaluation of postural balance training using a virtual reality bicycle system was performed. In the experiment, the effectiveness of virtual reality bicycle system on postural balance training was analyzed with four male subjects in their twenties. The parameters measured during cycling were cycling time, average velocity, number of times subject deviated from path, and weight shift. Those parameters were evaluated for the quantification of the extent of control. We also measured the parameters on postural control capability after 5th trial and 10th trial in a balance testing system with a force plate to find out the effectiveness of the training. In the balance test with force plate, it was found out that the weight shift was almost zero and the deviation from the target trace reduced significantly after the training with the virtual cycle. The result showed that the virtual bicycle system was an effective system as a rehabilitation training device.

• 대한의용생체공학회:의공학회지
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• 제23권3호
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• pp.207-216
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• 2002

본 논문은 가상 자전거 시스템을 이용한 자세균형 훈련의 정량적 평가에 대한 연구이다. 본 연구의 실험은 20명의 정상 성인을 대상으로 하여 자세균형에 미치는 요인들을 분석하였다 측정 파라메터로서 주행시간. 주행속력. 주행경로 이탈의 횟수. 압력중심, 그리고 체중이동에 대한 변수들을 추출하여 정량적으로 평가하였다 또한, 균형훈련의 효과를 향상시키기 위해, 체중이동에 따른 시각적 피드백 정보의 유용성을 분석하였다 실험결과. 반복훈련결과. 체중이동 분포의 visual feedback 정보를 제시했을때 COP의 총길이가 줄어들어 동요도가 줄고 체중이동값이 50 %에 가까워져 자세제어 및 조절능력이 향상됨을 알 수 있었다. 따라서 가상 자전거 시스템은 효율적인 자세균형 재활 훈련 장비로서 효과가 있음을 확인하였으며 분석방법은 재활훈련 분야에서 널리 활용될 수 있는 가능성을 보여 주었다.

• 대한통합의학회지
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• 제1권2호
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• pp.93-104
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• 2013

Purpose : The purpose of this study is balanced exercise program according to the supporting surface any affect women's ability to balance high heels. Methods : This study subjects were normal 20 females in their twenties. They were divided into stable supporting surface(n=10), unstable supporting surface(n=10), and they exercised three times a week for 5 weeks. In order to compare the difference of balance, the subjects were measured before and after training. Balance was examined using the balance master 7.0 version systems. Results : 1. There was significant difference values between pre-exercise and post-exercise of unstable surface group on the FORM-EO and FORM EC of MCTSIB and all of Unilateral Stance variables. 2. There was significant difference values between pre-exercise and post-exercise of stable surface group on the mean EPE, mean MXE, and mean DCL of LOS. 3. There was significant difference values between pre-exercise and post-exercise of unstable surface group of the rhythmic weight shift. 4. There was significant difference value in the slow directional control of rhythmic weight shift between groups after exercise. Conclusion : Training on stable supporting surface group and unstable supporting surface group improve balance.

• 공업화학
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• 제21권1호
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• pp.111-114
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• 2010

ASTM D5757-95에 따른 마모 반응기를 이용하여 수성 가스 반응에 사용되는 촉매들의 마모 특성을 고찰하였다. 저온 수성가스 촉매와 고온 수성가스 촉매들의 유동 현상, 입자 크기에 따른 영향을 고찰하였고 이에 따른 입도 분포 변화를 측정하였으며 유동층 매체로 이용되는 모래와 마모 특성을 비교하였다. 마모관 내부에서 기체 주입에 따른 마모가 일어나 촉매의 입자 크기가 감소하고 분포가 변화되었다. 또한 초기 촉매 입자 층의 40~50%에 해당하는 양이 비산되어 배출되었다. 촉매 종류별 비교로부터 저온 수성가스 촉매가 고온 수성가스 촉매보다 비산량이 적음을 알 수 있었고, 초기 촉매 입자의 크기별 비교로부터 초기 입도가 $212{\sim}300{\mu}m$에 해당하는 경우에 비산량이 상대적으로 적음을 알 수 있었다.

• KSBB Journal
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• 제13권3호
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• pp.295-302
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• 1998

Human Erythropoietin (EPO) gene is cloned in quail fibrosarcoma cell, QT35. Because molecular weight of EPO is similar to that of serum albumin, cell culture with serum containing medium makes purification of EPO very difficult. Using fractional factorial study, we have developed serum free medium for the recombinant QT35 cell lines, QT N4D4 and QT SY-IMP, which have cloned EPO with glutamine synthetase (GS) gene amplification system and with puromycin selective marker, respectively. Among the seven frequently used medium components, fibronectin, BSA, and EGF were the most important for EPO production. However, sufficient fibronectin supplement to the medium did not make any good attachment of QT35 to culture plate over 3 days. Therefore, to maximize EPO production, we attempted a medium-shift at confluence from serum containing medium to serum free medium(QT SFM6). Using the medium-shift protocol with QT SFM6, nearly the same productivity of EPO was achieved comparing with that without medium-shift. This result was true in both QT35 cell lines in three types of culture, i.e. T flask, microcarrier and roller bottle cultures.