• Journal of the Society of Naval Architects of Korea
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• v.54 no.2
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• pp.132-142
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• 2017

As the International Maritime Organization (IMO) recently introduced the Energy Efficiency Design Index (EEDI) for new ships building and the Energy Efficiency Operational Indicator (EEOI) for ship operation, thus an accurate estimation of added resistance of ships advancing in waves has become necessary. In the present study, OpenFOAM, computational fluid dynamics libraries of which source codes are opened to the public, was used to calculate the added resistance and motions of the KCS. Unstructured grid using a hanging-node and cut-cell method was used to generate dense grid around a wave and KCS. A dynamic deformation mesh method was used to consider the motions of the KCS. Five wavelengths from a short wavelength (${\lambda}/LPP=0.65$) to a long wavelength (${\lambda}/LPP=1.95$) were considered. The added resistance and the heave & pitch motions calculated for various waves were compared with the results of model experiments.

• Korean Journal of Community Nutrition
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• v.14 no.6
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• pp.756-766
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• 2009

This study was conducted to investigate the effects of weight control program on nutrient intakes and physical fitness of Korean obese adult women. The subjects of this study were 33 obese adult women aged 30-65 years residing in Seoul. The weight control program for obese women included nutrition education, cognitive behavioral therapy and exercise for 12 weeks. There were significant decrease (p < 0.001) of blood pressure and atherogenic index of obese women after the weight control program. Energy intake was significantly decreased (p < 0.001) from 1556.9kcal to 1044.9kcal after 12 weeks of the weight control program. Also protein, fat and carbohydrate intakes were significantly decreased. The ratio of energy intakes per day for the subjects was carbohydrate 64% : protein 16% : fat 20%. The frequency of vegetables intakes was significantly increased (p < 0.05) and there were no significant differences in other food groups. After the weight control program, muscle endurance, flexibility, balance and explosive muscular strength of subject's physical fitness were significantly improved. These results suggest that the weight control program for obese women may contribute to nutrient intakes reduction and improvement of physical fitness.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.4
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• pp.65-74
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• 2014

Unmanned aerial vehicles(UAVs) refer to the aircraft which carries no human pilot and is operated under remote control or in autonomous operational mode. As the UAVs can perform the dull, dangerous and difficult missions, various kinds of UAVs with different sizes and weights have been developed and operated for both civil and military application. As the avionics and communication technology related to the UAVs are matured, the demand for the UAVs is dramatically increased. Therefore, It is important to develope airworthiness process and regulations of the UAVs to minimize related risk to the man and environment. This paper describes related regulations and classification of the small UAVs for different international airworthiness authorities. The analysis of the CS-LURS verses Stanag 4702 and Stanag 4703 can provide guidelines for the generation of the airworthiness certification criteria for the small UAVs in civil sector. This paper conducted kinetic impact energy analysis of the loss of the small UAVs control scenarios and of the very small UAVs under 66 joules. Based on the analysis, the energy impact analysis can be considered before the design certification approval for the small UAVs.

• Journal of the Korean Institute of Gas
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• v.17 no.5
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• pp.75-80
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• 2013

In this study, the effect of phosphorus flame retardants on the flame retardancy of the rigid polyurethane foam(PUF) was studied. Tetramethylene bis(orthophos-phorylurea)[TBPU] and Tris(2-chloroethyl) phosphate[TCEP], Tris(2-chloropropyl)phosphate [TCPP], Triethyl phosphate[TEP] were used as flame retardant. It was found that TBPU added PUF exhibits low mean heat release rate(HRR), peak HRR, effective heat of combusion(EHC), mass loss rate (MLR), CO yield and $CO_2$ compared other flame retardants.

• Journal of Electrical Engineering and Technology
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• v.11 no.4
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• pp.869-877
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• 2016

Necessity has compelled man to improve upon the art of tapping wind energy for power generation; an apt reliever of strain exerted on the non-renewable fossil fuel. The power generation in a Wind Farm (WF) depends on site and wind velocity which varies with time and season which in turn determine wind power modeling. It implies, the development of an accurate wind speed model to predict wind power fluctuations at a particular site is significant. In this paper, Box-Jenkins ARIMA (Auto Regressive Integrated Moving Average) time series model for wind speed is developed for a 99MW wind farm in the southern region of India. Because of the uncertainty in wind power developed, the economic viability and reliability of power generation is significant. Life Cycle Costing (LCC) method is used to determine the economic viability of WF generated power. Reliability models of WF are developed with the help of load curve of the utility grid and Capacity Outage Probability Table (COPT). ARIMA wind speed model is used for developing COPT. The values of annual reliability indices and variations of risk index of the WF with system peak load are calculated. Such reliability models of large WF can be used in generation system planning.

• Macromolecular Research
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• v.17 no.8
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• pp.603-608
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• 2009

Novel ultra-high molecular weight polyethylene (UHMWPE)/zirconia composites were previously prepared by the in situ polymerization of ethylene using a Ti-based Ziegler-Natta catalyst supported on to the surface of zirconia, as a bearing material for artificial joints. Tribological tests revealed that a uniform dispersion of zirconia in UHMWPE markedly increased the wear resistance. The effects of zirconia content on the oxidation behavior of the ${\gamma}$-ray-treated UHMWPE/zirconia composite surfaces were examined. The oxidation index that estimates the oxidation degree as the content of total carbonyl compounds was monitored using Fourier transform infrared spectroscopy-attenuated total reflectance. The changes in the surface composition due to the oxidation were confirmed by electron spectroscopy for chemical analysis. The extent of oxidation decreased with increasing zirconia content, which was attributed to the increased crystallinity as well as the decreased polymer portion of the UHMWPE/zirconia composites.

• Journal of Nutrition and Health
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• v.25 no.2
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• pp.150-161
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• 1992

The purpose of this study was to evaluate the riboflavin status of primary school children. Fiftyone subjects were selected as obese group and fiftyfive subjects were selected as control group according to Body Mass Index(BMI) of fifth-graders at a primary school in Taegu. For each subject information on nutrient intake and daily activity pattern were obtained by questionnaire. The riboflavin status was evaluated by urinary riboflavin exvretion The daily energy expenditure per kilogram of body weight was significantly lower in obese group(=47kcal/day) than in control group(=58kcal/day) (p<0.001) However the entire energy consumption was siginificantly greater in the obese children(=2005kcal/day) than their nono-baser peers(=1837kcal/day)(p<0.001). Riboflavin intake was 0.67mg/100kcal in the control group and 0.61mg/1000kcal in the obese group. Thus intakes for both groups met the current group and control group were 86.9$\mu\textrm{g}$/day and 98.7$\mu\textrm{g}$/day. repectively. There was no significnat Assesment of clinical signs of riboflavin deficiency indicated that angular lesion was 4.7% and glossitis was 6.6% of all subjects. Thirty one percent of subjects excrete riboflavin below 78$\mu\textrm{g}$/g creatinine which is defined as deficient. Therefore this group would be considered at high risk for developing riboflavin deficiency. From this study current recommendation of 0.6mg/1000kcal of riboflavin intake may not be adequate during growth and associated stress.

• Journal of Surface Science and Engineering
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• v.46 no.5
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• pp.229-233
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• 2013

The small punch(SP) tests that can be applied to high strength sheet steel in automobile were carried out to evaluate the behavior of hydrogen embrittlement of DP sheet steels. In order to charge hydrogen at DP sheet steels, DP sheet steels were treated by the electrochemical hydrogen charging method under the charging conditions of current densities of 100, 150 and 200 $mA/cm^2$ for charging times of 5, 10, 25 and 50 hrs. Respectively, After hydrogen charging with experimental conditions, SP tests were performed. From the SP results, the correlations between the variation of bulb diameters and bulb heights with the hydrogen charging conditions were analysed. It was shown that the variation of bulb diameters were not significant with the hydrogen embrittlement due to the amounts of hydrogen charging. On the other hand, the bulb heights were observed to decrease with increasing hydrogen contents. It was thought that these results of the variation of bulb shapes after SP tests would be estimated as the index of evaluation of hydrogen embrittlement.

• Journal of Korean Medicine for Obesity Research
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• v.2 no.1
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• pp.53-61
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• 2002

Objective: Obesity is closely related to several factors such as genetic factors, energy intake and energy expenditure. It was said that alcohol & food habits were important to formation of obesity. The purpose of this study are to find out the alcohol & food habitual characteristic of obese adult men and to promote the health of these men. Method: From May, 2000 to November, 2001, We collected 75 eases obese patients, who visited to the Health Examination Center Dept. of Kangnam oriental medicine hospital, Dongguk University who took the health examination, and control group who were matched by age and sex. We investigated the alcohol & food habits by questionnaire. Results and Conclusions: 1. The patients over BMI 25 were in excess of the standard of obesity such as Modified Broca $^{\circ}{{\O}}s$ Index. Percent Body Fat, Abdominal Fat Distribution. But, the patients below BMI 20 were normal range of obesity degree. 2. Abdominal Fat Distribution was increased according to age and physical activity was decreased in obese group. 3. The mean of total calory by alcohol in a month was 4324.6kcal in obese group while control group was 2206.8kcal. 4. In the comparison of food habit, obese group is higher than control group in 7 articles of the 13 articles which influenced obesity.

• Journal of Climate Change Research
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• v.8 no.1
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• pp.63-71
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• 2017

It is recognized that tetrafluoromethane ($CF_4$) has a great influence on global warming. The $CF_4$ is known to have a large impact on climate change due to its large global warming index. In this study, a waterjet plasma scrubber (WPS) was designed and manufactured for the $CF_4$ decomposition. The WPS is a novel technology which is combined a gliding arc plasma and water injection at the center of the plasma discharge. This can give an innovative way for $CF_4$ decomposition by achieving larger plasma columnand generating OH radicals. A performance analysis was achieved for the design factors such as waterjet flow rate, total gas flow rate, consumption electric power, and electrode gap. The highest $CF_4$ decomposition and energy efficiencies were 64.8% and 6.43 g/kWh, respectively; Optimal operating conditions were 20 mL/min of waterjet flow rate, 200 L/min total gas flow rate, 5.3 kW consumption electric power, and 4.4 mm electrode gap. As for the 2 stage reactor of the WPS, the $CF_4$ decomposition efficiency improved as the 85.3% while the energy efficiency decreased as the 5.57 g/kWh.