• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.5
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• pp.914-923
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• 2002

Recently, there has been considerable interest in micro gyroscopes made of silicon chips. It can be applied to many micro-electro-mechanical systems (MEMS): devices for stabilization, general rate control, directional pointing, autopilot systems, and missile control. This paper shows how the mechanical design of the gyroscope can be done using axiomatic design, followed by the application of the Taguchi robust design method to determine the dimensions of the parts so as to accommodate the dimensional variations introduced during manufacturing. Functional requirements are defined twofold. One is that the natural frequencies should have fixed values, and the other is that the system should be robust to large tolerances. According to the Independence Axiom, design parameters are classified into a few groups. Then, the detailed design process is performed fellowing the sequence indicated by the design matrix. The dimensions of the structure are determined to have constant values fur the difference of frequencies without consideration of the tolerances. It is noted that the Taguchi concept is utilized as a unit process of the entire axiomatic approach.

• Journal of Energy Engineering
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• v.20 no.1
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• pp.1-7
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• 2011

The performance and life-cycle costs of electric vehicle(EV) and hybrid electric vehicle(HEV) depend inherently on battery packs. Temperature uniformity in a pack is an important factor for obtaining optimum performance for an EV or HEV battery pack, because uneven temperature distribution in a pack leads to electrically unbalanced battery cells and reduced pack performance. In this work, a three-dimensional modeling was carried out to investigate the effects of operating conditions on the thermal behavior of a lithium-ion battery pack for an EV or HEV application. Thermal conductivities of various compartments of the battery were estimated based on the equivalent network of parallel/series thermal resistances of battery components. Heat generation rate in a cell was calculated using the modeling results of the potential and current density distributions of a battery cell.

• Survey Research
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• v.8 no.1
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• pp.55-79
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• 2007

This article attempts to provide an overview of the exit polls for the 2006 local elections in Korea. The sampling method, sampling error, non-response rate, and prediction error of the exit polls are reviewed. Also, we explore the fact that the propensity to vote varies according to age and gender of voters. In terms of age and gender, the representativeness of the sample is investigated by comparing to the data released by the National Election Commission. Through this empirical research, we show that the exit poll samples are unbalanced in terms of age and this unbalance may be one of the causes of bias occurred in the prediction of the 2006 local election results. The design effects of the sample design implemented for the exit polls are also examined.

• The Korean Journal of Food And Nutrition
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• v.22 no.2
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• pp.166-176
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• 2009

This study was performed to develop dietary education programs for children, by researching the actual conditions of dietary education and its demand aimed at teachers in child centers in Masan. Most of the interviewed teachers were in their 20s(71%) with under 5 years teaching experiences(56.8%), and working in a kindergarten environment(34.9%). The rate of doing dietary education on mealtime was 96.4%. The main items taught pertained to 'not leaving food(20.6%)' and 'washing hands before meals(20.5%)'. The primary teaching method for students with unbalanced eating habits was 'eating after teaching them to understood(76.8%). The primary reward for good behavior was 'using food(76.8%)', usually as 'candy'(50.8%) or 'cookies'(25.8%). The desirable dietary education type was 'during spare moments(52.6%)' and 'at mealtime (23.5%)'. The concepts taught were 'balanced eating(23.2%)' and 'food hygiene(21.2%), and the students were interested in 'the roles of foods and nutrients'(34.5%), 'balanced eating(20.9%)', and 'food hygiene(19.1%)'. Educational activities encompassed 'pictures and drawing(25.7%)', 'fairy tales(23.4%)', 'songs(19.4%)', and 'play(14.1%)'. Also, the activities of most interest were 'fairy tales(29.4%)', 'play(24.4%)', and then 'songs(23.1%)'. The greatest difficulties during dietary education were 'attracting interest from the children(37.8%)' and 'making and purchasing materials(33.9%)'. Approximately, 44.2% of the teachers had experiences in dietary education, and 96.4% stated teachers had the intention to participate in dietary education. They want to address 'child meal direction(23.0%)', 'health problems(22.7%)', and then 'child nutrient requirements (17.3%)'. Also the majority wanted it two times per year(57.6%) or one time per year(30.9%). This study indicated that proper dietary education must be established in child centers by developing various practical dietary education programs and then implementing them.

• Journal of the East Asian Society of Dietary Life
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• v.13 no.1
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• pp.9-18
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• 2003

This study was conducted to investigate the nutritional knowledge, nutrients intake and the assessment of dietary behavior of old peoples living in Incheon area. Two hundred and three elderly were examined using the questionnaire. The results of this study are summarized as follows. 1. The old people was lacking in correct information about nutrition and diseases. 2. The nutritional knowledge scores of old women were higher than those of old men and the scores went up according to the amount of pocket money. 3. The amount of vitamin C and phosphorus intakes were higher than those of the RDA, protein intake reached the level of the RDA. The vitamin B$_2$intake, however, was below 75% of the RDA and that of calcium was very low in women, especially. 4. Most of subjects had a meal regularly three times a day and the skipping rate of breakfast was very low. Dey had a moderate meal volume and did not have an unbalanced diet. Dey nearly do not take the processed food, dine out and exceed in the cholesterol intake. 5. They took green and yellow vegetables and, milk and milk products relatively small. On the other hand, the intake of caffein beverage was relatively high. the rates of drinking and smoking were low. From these results, we may propose the conclusion as follows: The old people were much concerned about the nutrition and diseases, but they had no correct informations about them. Therefore, the program of nutrition and dietary behavior for their healthy elderly life had to be prepared and to be applied to them immediately.

• Journal of Microbiology and Biotechnology
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• v.7 no.4
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• pp.215-222
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• 1997

The regulatory mechanism of the flux of acetyl-CoA in Alcaligenes eutrophus in unbalanced growth conditions was investigated using a PHB-negative mutant and transformants reintroduced PHB-biosynthesis enzymes through the transformation of cloned phbCAB genes. The PHB-negative mutant was defected absolutly in PHB synthase but partially in ${\beta}$-ketothiolase and acetoacetyl-CoA reductase, and excreted substantial amount of pyruvate to culture broth at late growth phase. The excretion was due to the inhibitory effect of acetyl-CoA on the activity of pyruvate dehydrogenase. The cloned phbC and phbCAB genes were transformed to the PHB-negative mutant strain to reintroduce PHB biosythesis enzymes. Pyruvate excretion could be decreased substantially but not completely by transformation of PHB synthase alone, while pyruvate excretion was ceased by transformation of all three PHB biosynthesis enzymes. To identify the most critical PHB biosynthesis enzyme influencing on the flux of acetyl-CoA, the effect of the variation of PHB biosynthesis enzymes on pyruvate dehydrogenase was investigated. ${\beta}$-Ketothiolase influenced the activity of pyruvate dehydrogenase more sensitively than PHB synthase. ${\beta}$-Ketothiolase, the first step enzyme of PHB biosynthesis that condense acetyl-CoA to acetoacetyl-CoA, seems to be the major enzyme determining the flux of acetyl-CoA to PHB biosynthesis or TCA cycle, and the rate of PHB biosynthesis in A. eutrophus.

• Applied Biological Chemistry
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• v.41 no.6
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• pp.451-456
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• 1998

To find out the repeated application effect of chicken and pig manure composts on tomato growth and soil physico-chemical properties, different rates of the composts were applied to greenhouse soils with low fertility for 3 years and tomato was grown annually. As application rate of compost increased, the growth and fruit yield of tomato increased markedly, and there are also a little increase in sugar content in fruit juice and weight per fruit. When only compost was applied, however, physical and chemical properties in soil showed to be unbalanced such as significantly low bulk density and hardness, and high porosity as well as high organic matter and exchangeable K content, and low exchangeable Ca content than those of optimum range for soil diagnosis. Therefore mixed use of compost and chemical fertilizer is more promising way than the only use of compost to make suitable physico-chemical properties for tomato growth.

• Nuclear Engineering and Technology
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• v.52 no.3
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• pp.597-609
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• 2020

Accident Tolerant Fuels have been widely studied since the Fukushima-Daiichi accident in 2011 as one of the options on how to further enhance the safety of nuclear power plants. Deposition of protective coatings on nuclear fuel claddings has been considered as a near-term concept that will reduce the high-temperature oxidation rate and enhance accidental tolerance of the cladding while providing additional benefits during normal operation and transients. This study focuses on experimental testing of Zr-based alloys coated with Cr-based coatings using Physical Vapour Deposition. The results of long-term corrosion tests, as well as tests simulating postulated accidents, are presented. Zr-1%Nb alloy used as nuclear fuel cladding serves as a substrate and Cr, CrN, Cr_xN_y layers are deposited by unbalanced magnetron sputtering and reactive magnetron sputtering. The deposition procedures are optimized in order to improve coating properties. Coated as well as reference uncoated samples were experimentally tested. The presented results include standard long-term corrosion tests at 360℃ in WWER water chemistry, burst (creep) tests and mainly single and double-sided high-temperature steam oxidation tests between 1000 and 1400℃ related to postulated Loss-of-coolant accident and Design extension conditions. Coated and reference samples were characterized pre- and post-testing using mechanical testing (microhardness, ring compression test), Thermal Evolved Gas Analysis analysis (hydrogen, oxygen concentration), optical microscopy, scanning electron microscopy (EDS, WDS, EBSD) and X-ray diffraction.

• Journal of the Korean Home Economics Association
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• v.38 no.8
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• pp.85-97
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• 2000

The purpose of this study was to evaluate the dietary attitude and food behavior of elementary, middle and high school students in Korea. The subjects in this study were 7,698 boys and girls in large cities in Korea. The questionnaire was made and distributed to the students to answer the questions. Followings are the results of this study : 1) Father and mother's average ages were 45 and 41 years old, respectively. 2) Most students thought dietary life was more important than clothing or residentary life. Dietary habits such as irregularity of meal, frequencies of skipping meal and of eating out increased in higher grade than in lower grade, and in girls than in boys. 3) Most students, especially in elementary school, recognized that their own bad dietary habbit was unbalanced diet. Irregular meal time and eating too much were also pointed out as problems by middle and high school students. 4) Most students thought that the most effective meal for health was breakfast, but they replied the tartest meal as dinner. 5) Students tended to prefer Korean style food. Cooked rice and kimchi, ramyun, and pizza were ranked the most preferred food when they were hungry. 6) Elementary school students ate meals more regularly than higher grade students, and girls ate meals more regularly than boys. 7) Skipping rate of breakfast was higher than that of lunch or dinner, and the percentage of meal skipping students was increasing with grade elevation. No time to eat or eating between meals was the reasons of irregular meal time. 8) Frequency of dining with family was decreased, but frequency of eating out with friends was increased with increasing grade. The gravity of dining out is increasing rapidly in Korean adolescents. Therefore, nationwide nutrition education policy is necessary to constitute a right dietary environment and a desirable dietary altitude.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1669-1673
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• 2008

A new cycle ergometer using a Magneto-Rheological (MR) rotary brake system has been developed for rehabilitation of hemiplegia patients to reduce uneven pedaling characteristics. For this purpose, a control method to adjust the resistance of the MR rotary brake in real time based on the magnitude of the muscular force exerted by the subject has been devised so that the mechanical resistance to the pedaling can be minimized when the affected leg was engaged for pedaling. A series of experiments were carried out with and without the engagement of this real-time control mode of MR rotary brake at different pedaling rate to find out the effect of the real-time control mode. The characteristics of the pedaling for these specific conditions were analyzed based on the variations in angular velocities of the pedal unit. The results showed that the variations in the angular velocities were decreased by 42.9% with the control mode. The asymmetry of pedaling between dominant and non-dominant leg was 19.63% in non-control mode and 1.97% in the control mode. The characteristics of electromyography(EMG) in the lower limbs were also measured. The observation showed that Integrated EMG(IEMG) reduced with the control mode. Therefore, the new bicycle system using MR brake with the real time control of mechanical resistance was found to be effective in recovering the normal pedaling pattern by reducing unbalanced pedaling characteristics caused by disparity of muscular strength between affected and unaffected leg.