• Proceedings of the KSR Conference
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• 2009.05b
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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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• v.6 no.4
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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.

• Journal of the Korea Society for Simulation
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• v.16 no.4
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• pp.43-55
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• 2007

Moving average(MA) and exponentially weighted moving average(EWMA) are the two most popular control methods in manufacturing. Both methods are optimized under the assumption that the exact control equation is known. This paper focuses on the problems rising from estimation errors. Based on the accuracy of the estimated parameter and the range of the weight parameter $\lambda$, the limitations are identified and the performance of methods are evaluated. Optimal adjustment for process shift with misestimated control model and its application control methods to actual process is researched. The efficiency of proposed method is evaluated through simulation.

• The Journal of Korean Obstetrics and Gynecology
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• v.21 no.3
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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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• v.34 no.6
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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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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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.

• Journal of Biomedical Engineering Research
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• v.23 no.3
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• pp.207-216
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• 2002

This Paper describes a quantitative analysis of Postural balance training using virtual bicycle system. We have used a virtual bicycle system that combines virtual reality technology with a bicycle . In this experiment, 20 normal adults were tested to investigate the influencing factors on Postural balance. Several factors including cycling time. cycling velocity. number of times of Path deviation, center of Pressure(COP) . and weight shift were extracted and evaluated to quantify the extent of control. Also, To improve the effect of balance training, we investigated the usefulness of visual feedback information by weight shift The results showed that the system was effective Postural balance rehabilitation training device and. in addition. the analysis method might have a wider applicability to the rehabilitation field.

• Journal of The Korean Society of Integrative Medicine
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• v.1 no.2
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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.

• Applied Chemistry for Engineering
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• v.21 no.1
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• pp.111-114
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• 2010

In the attrition reactor for the American Society for Testing and Materials (ASTM) D5757-95, the attrition characteristics of catalysts for water gas shift reaction were investigated. The effects of attrition characteristics of low temperature shift catalysts (LTS) and high temperature shift catalysts (HTS) on fluidization phenomena and average particle size were investigated and compared with the attrition characteristics of sand particles. The particle size of catalysts was decreased and particle size distribution in attrition tube was changed due to the effect of gas injection. About 40~50 wt% samples of original catalyst particles were entrained and lost. The amount of fly ash of LTS catalyst was less than that of HTS. Also, the weight of entrained particles which had original particle size of $212{\sim}300{\mu}m$ was lower than any other cases.

• KSBB Journal
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• v.13 no.3
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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.