• Journal of Families and Better Life
• /
• v.25 no.3 s.87
• /
• pp.77-87
• /
• 2007

This study purports to understand the direct and indirect effects between eating disorder behavior of female adolescents and their body-related variables(concerning the degree of diet regime, weight control, body satisfaction, and obesity), self-esteem and internal control, by checking three sub-categorized behavior of eating disorders of diet behavior, bulimia behavior, and eating control behavior. The sample group used for the study consisted of 190 female high school students and 292 female university students; measurement devices used for the study were those of body-related variables, self esteem and internal control, and eating disorder behavior; and data analysis was performed using ${\chi}2$, t-test, Pearson's correlation, regression analysis and path analysis. The results are as follows. First, there is a significant difference between university students and high school students regarding their body satisfaction, weight control experience, and self esteem. University students are more satisfied with their body, have higher self esteem, and control their weight better than high school students. Second, diet behavior shows a correlation with the degree of diet interest, weight control experience, and body satisfaction. Body satisfaction and internal control proved to be correlated with bulimia behavior, while weight control experience, obesity, and self esteem were correlated with eating control behavior. Third, the variables that showed a direct influence on diet behavior as an eating disorder are diet interest, weight control experience, body satisfaction and obesity, in that the explanatory power of the variables is 60.7% with the highest mark on obesity. The variables that showed effects on bulimia are body satisfaction and internal control with an explanatory power of 2.8%. Indirect variables effecting bulimia include objects, diet interest, body satisfaction, and self esteem. The variable with a direct influence on eating control behavior was self esteem with and explanatory power of 4%, whereas the variables of objects, diet interest, body satisfaction, weight control experience, and internal control were all indirectly correlated with eating control behavior.

• Nuclear Engineering and Technology
• /
• v.30 no.4
• /
• pp.353-363
• /
• 1998

The H$_{\infty}$ algorithms of the mixed weight sensitivity is used for the robust design of the reactor power control system. The mixed weight sensitivity method requires the selection of the proper weighting functions for the loop shaping in frequency domain. The complexity of the system equation and the non-convexity of the problem make it very difficult to determine the weighting functions. The genetic algorithm which is improved and hybridized with the simulated annealing is applied to determine the weighting functions. This approach permits an automatic calculation and the resultant system shows good robustness and performance.

• Journal of Power Electronics
• /
• v.11 no.5
• /
• pp.621-631
• /
• 2011

In space qualified DC-DC converters, optimization of the following electrical characteristics is of greater interest in comparison with other specifications; power loss/efficiency, output voltage ripple and volume/weight. The main goal of this paper is to present an appropriate solution for optimizing the above mentioned characteristics. For this purpose, a comprehensive power loss model of a DC-DC converter is fully developed. Proper models are also demonstrated for assessment of the output voltage ripple and the utilized transformer volume as the bulkiest component in a DC-DC converter. In order to provide a test bed for evaluation of the proposed models, a 50W push-pull DC-DC converter is designed and implemented. Finally, a novel cost function with three assigned weight functions is proposed in order to have a trade-off among the power loss, the output voltage ripple and the utilized transformer volume of the converter. The cost function is optimized for applications in which volume has the highest priority in comparison with power loss and ripple. The optimization results show that the transformer volume can be decreased by up to 51% and this result is verified by experimental results. The developed models and algorithms in this paper can be used for other DC-DC converter topologies with some minor modifications.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.12
• /
• pp.162-169
• /
• 2020

This study was conducted from November 25 to December 4, 2019, to unmask differences in physical fitness based on the weight class of high school Ssirum elite-players. A total of 28 high school Ssirum elite-players were compared and analyzed by measuring physical factors (muscle strength/power, agility, anaerobic power, aerobic ability, flexibility, and isokinetic muscle function) by weight class. Data were analyzed using SPSS ver. 23.0. One-way ANOVA was used for comparison between groups. There was no difference by weight class in terms of grip strength, sit-ups, sergeant jump, long jump, flexibility, side step, and reaction time. Evaluation of back muscle strength revealed that the group with more than 100 kg had greater strength than lower weight categories, whereas it was lower in the sit-ups, 20 m shuttle run and the relative values anaerobic power. Considering isokinetic muscle function, no difference was observed between the groups of back muscle strength and knee joint. The results of this study indicate that amongst the high school Ssirum elite-players, there is no difference in muscle power, flexibility, agility, and anaerobic average power per body weight, isokinetic trunk strength, and knee flexion strength, when evaluated according to weight class.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.1825-1831
• /
• 2011

One of the major trends in traction power electronics is increasing the switching frequencies. The advances in the frequency elevation have made it possible to reduce the total size and weight of the passive components such as capacitors, inductors and transformers in the DC/DC converter and hence to increase the power density. The traction dynamic performance is also improved. This document describes several aspects relating to the design of resonant DC/DC converter operating at high frequency(10KHz) and the converter topologies and the control method of MAGLEV, which result in soft switching, are discussed.

• Korea Trade Review
• /
• v.44 no.1
• /
• pp.193-205
• /
• 2019

It is important to accurately analyze the various factors such as the local situation of the purchasable countries and the international situation in order to export defense industrial goods developed in Korea and to enter overseas markets based on the results. In the case of defense materials, unlike the civilian sector, there are a limited number of countries with high export potential. Therefore, to select a possible export market, it is necessary to consider the purchasing power index through the examination of the purchasability of the exportable market. Therefore, the present study chose a total of 18 purchasing power indicators in five major categories of economic power, military power, defense science and technology level, friendly relations with Korea, and possibility of dispute. By calculating each weight with AHP and Fuzzy-AHP analysis, the results was presented the purchasing power index and the weighting. Based on the results will contribute to the study on the method of selecting the export market of the defense materials and the establishment of the export policy of the defense industry.

• Aerospace Engineering and Technology
• /
• v.6 no.2
• /
• pp.164-170
• /
• 2007

In this paper, the development results of electromechanical TVC actuation system is described in the aspect of design, analysis, manufacturing and test. The kinds of prime power for TVC actuation system is classified by the variety of propulsion system of launch vehicle. The electric power by battery is the sole candidate for prime power of TVC actuation system at the view point of feasible domestic infra technologies for the present. The characteristic analysis study is performed between electromechanical and electrohydraulic actuation system with respect to power efficiency, performance and weight efficiency. The electromechanical actuation system has superiority of power and weight efficiency according to less opportunity of power conversion process.

• Physical Therapy Rehabilitation Science
• /
• v.4 no.2
• /
• pp.115-120
• /
• 2015

Objective: To examine the effects of different shoe weights on lower leg muscle fatigue when walking by electromyographic (EMG) analysis due to the most effective weight for loading not being established. Design: Cross-sectional study. Methods: Thirty healthy university students (15 male, 15 female) were enrolled and randomly assigned into three conditions, which included wearing athletic shoes with an addition of 300 g, 500 g, and 1,000 g weights respectively. Prior to walking, all subjects were instructed to sit in a chair for 10 minutes. All subjects walked at a speed of 3.6 m/s on a treadmill for 20 minutes without rest. EMG measurements were taken using the median power frequency to assess for the effect of the different weight of shoes on muscle fatigue of the soleus, gastrocnemius, and tibialis anterior while walking on a treadmill in an upright posture. EMG measurements were taken during the first and last 30 seconds of walking. Results: In terms of muscle fatigue, for the soleus, the median power frequency was significantly lower with 1,000 g compared with 300 g and 500 g (p<0.05). For the tibialis anterior, the median power frequency was significantly lower with 1,000 g than 300 g and 500 g (p<0.05). For the gastrocnemius, the median power frequency was significantly lower with 1,000 g compared with 300 g (p<0.05). Conclusions: Increased shoe weight increases soleus, gastrocnemius, and tibialis anterior muscle fatigue during ambulation.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.27 no.4
• /
• pp.44-51
• /
• 2019

This study analyzes the trade patterns that occur between Korea and ASEAN countries through air transport, one of Korea's trade transport methods. In order to understand the detailed characteristics of the air transport sector, the dependent variables were analyzed by dividing them into amount and weight. As a result, the amount of exports, imports, and trade was proportional to GDP per capita representing income level, and inversely proportional to GDP representing national economic power. In terms of air transport weight, exports, imports and trade were all proportional to GDP representing economic power and inversely proportional to GDP per capita representing income levels. In addition, the national area acted as a factor to reduce the trade volume, and the number of airports and inland countries did not show any significant results.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.6 no.3
• /
• pp.265-272
• /
• 2001

The traditional 60[Hz] power supply for during magnetron in microwave oven has disadvantages of heavy weight and low efficiency due to 60[Hz] High Voltage Transformer(HVT), capacitor and th phase control of thyristors. To alleviate these disadvantages, this paper proposes a 20[kHz] phase-shifted Full-Bridge(FB) Zero-Voltage-Switched(ZVS) PWM converter for driving a 600[W] magnetron in an 1[kW] microwave oven. The proposed converter has advantages of light weight and high power density.