• Journal of the Korean Solar Energy Society
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• v.33 no.4
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• pp.15-22
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• 2013

The purpose of this study is to analyse the effects of air conditioned room controlled by PMV(Predicted Mean Vote)for energy consumption and human comfort in office building. The 'EnergyPlus' was used for the evaluation of indoor thermal environment and energy consumption by the controls of room temperature and PMV. The result indicates that the PMV control could prove more profitable method for improvement of indoor thermal environment and energy conservation. Consequently, PMV control has a distinct advantage over most other control methods. An additional study is required to establish the various thermal comfort control for rooms on the basis of this work.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.113-115
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• 2002

The Monte Carlo simulation method is a numerical solution to a problem that models objects interacting with other objects or their environment based upon simple object-object or object-environment relationships. In spite of its great accuracy, It was turned away because of long calculation time to simulate a model. But, it is used to simulate a linear accelerator frequently with the advance of computer technology. To simulate linear accelerator in Monte Carlo simulations, there are many parameters needed to input to Monte Carlo code. These data can be supported by a linear accelerator manufacturer. Although the model of a linear accelerator is the same, a different characteristic property can be found. Thus, we performed a commissioning process of 6MV photon beam in Varian 2300C/D model with BEAM/EGS4 Monte Carlo code. The head geometry data were put into BEAM/EGS4 data. The mean energy and energy spread of the electron beam incident on the target were varied to match Monte Carlo simulations to measurements. TLDs (thermoluminescent dosimeter) and radiochromic films were employed to measure the absorbed dose in a water phantom. Beam profile was obtained in 40cm${\times}$40cm field size and Depth dose was in 10cm${\times}$10cm. At first, we compared the depth dose between measurements and Monte Carlo simulations varying the mean energy of an incident electron beam. Then, we compared the beam profile with adjusting the beam radius of the incident electron beam in Monte Carlo simulation. The results were found that the optimal mean energy was 6MV and beam radius of 0.1mm was well matched to measurements.

• Journal of the Korean Dietetic Association
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• v.7 no.3
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• pp.267-273
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• 2001

The purpose of this study was to investigate the relationship between alcohol consumption and nutritional status of university male freshman in Chungnam area. The total of 111 subjects took part in the study and, they were observed general characteristics, alcohol consumption status, and nutrient intake using questionnaires. The mean age, height, weight, and BMI of the subjects were 19.3 years, 174.3㎝, 65.2㎏, and 21.5㎏/$m^2$ respectively. The mean alcohol consumption, and energy intake from alcohol were 7.8g/day, 55.3kcal/day. A significant number of subjects(48.2%) answered their frequency of alcohol consumption was once 2 weeks. Only 4.6% of subjects answered never drink. In almost subjects, alcohol consumption have been stared since they were adolescents, and major type of alcoholic beverage was 'soju'. The mean energy intake was 1985.6kcal and, energy ratio from carbohydrate, protein, fat was 58 : 15 : 27. There were significantly positive correlation among alcohol consumption and, body weight(p<0.05), intake of food, (p<0.05), energy(p<0.001), animal fat(p<0.05), fiber(p<0.05), vitamin $B_2$(p<0.05) and niacin(p<0.05). The alcohol consumption period showed a significantly positive correlation with alcohol consumption per one time(p<0.05). In summary, high consumption of alcohol in subjects was observed. Also, increase of alcohol consumption was related to weight gain and nutritional imbalance. Therefore, it is need that nutrition education for prevention of high alcohol consumption in university freshman and adolescents.

• Journal of Mechanical Science and Technology
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• v.18 no.10
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• pp.1782-1798
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• 2004

A numerical study of a natural convection in a rectangular cavity with the low-Reynolds-number differential stress and flux model is presented. The primary emphasis of the study is placed on the investigation of the accuracy and numerical stability of the low-Reynolds-number differential stress and flux model for a natural convection problem. The turbulence model considered in the study is that developed by Peeters and Henkes (1992) and further refined by Dol and Hanjalic (2001), and this model is applied to the prediction of a natural convection in a rectangular cavity together with the two-layer model, the shear stress transport model and the time-scale bound ν$^2$- f model, all with an algebraic heat flux model. The computed results are compared with the experimental data commonly used for the validation of the turbulence models. It is shown that the low-Reynolds-number differential stress and flux model predicts well the mean velocity and temperature, the vertical velocity fluctuation, the Reynolds shear stress, the horizontal turbulent heat flux, the local Nusselt number and the wall shear stress, but slightly under-predicts the vertical turbulent heat flux. The performance of the ν$^2$- f model is comparable to that of the low-Reynolds-number differential stress and flux model except for the over-prediction of the horizontal turbulent heat flux. The two-layer model predicts poorly the mean vertical velocity component and under-predicts the wall shear stress and the local Nusselt number. The shear stress transport model predicts well the mean velocity, but the general performance of the shear stress transport model is nearly the same as that of the two-layer model, under-predicting the local Nusselt number and the turbulent quantities.

• Journal of Community Nutrition
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• v.4 no.1
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• pp.12-21
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• 2002

This study was conducted to investigate the dietary intake, anthropometric data, and association between two factors and main food sources contributing macronutrients for overweight and obese females. Subjects were 85 adult females (overweight : 28, obese 57) where mean age was 38.7y. The results are summarized as follows. Mean fat percent, BMI, obesity rate were 29.3, 23.9 and 15.1%, respectively for overweight women and 32.7, 28.3, 36.4%, respectively for obese women. There were significant differences for most of the anthropometric data between groups. Fat percent for all subjects was significantly correlated with weight, waist circumference, hip circumference, mid arm circumference or skinfold thickness for the triceps, subscapular and suprailiac (p < 0.001). The parameter which showed the highest correlation coefficient (r=0.6156) with fat Percentage was the waist to hip ratio. Any significant differences were not found in dietary intake of nutrients or in diet composition between groups. The mean energy intake was 2090.1kcal (104% of RDA) for overweight women and 2113.0kcal (106% of RDA) for obese women. PFC ratio for overweight was 17 : 24 : 59 and 18 : 23 : 58 for obese subjects, which can be regarded as higher fat and lower carbohydrate percentages compared to recommended PFC ratio (15 20 65) .4) Fat intake was positively correlated (r : 0.2301, p < 0.05) with the triceps skinfold thickness, protein intake was also positively correlated with waist circumference (r=0.2668, p < 0.05) or fat weight(r: 0.2406, p < 0.05) .5) The main food items that contributed to energy intake for overweight or obese subjects were similar (rice, pork, bread, grapes, barley) except com oil in overweight or instant noodle for obese group. The subjects in this study were taking less energy from rice and more energy from pork and bread than women from 98 National Health and Nutrition Survey. Because there were no significant differences of dietary data between overweight and obese group, further investigation considering basal metabolic rate or activity would be needed.

• Environmental and Resource Economics Review
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• v.20 no.2
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• pp.229-254
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• 2011

In this paper, we decomposed Greenhouse-Gas emissions of Korea's manufacturing industry using LMDI (Log Mean Divisia Index) method. Changes in $CO_2$ emissions from 1991 to 2007 studied in 5 different factors, industrial production (production effect), industry production mix (structure effect), sectoral energy intensity (intensity effect), sectoral energy mix (energy-mix effect), and $CO_2$ emission factors (emission-factor effect). By results, the structure effect and intensity effect has a role of reducing GHG emissions and The role of structure effect was bigger than intensity effect. The energy mix effect increased GHG emissions and emission-factor effect decreased GHG emissions. By time series analysis, IMF regime affected the GHG emission pattern. the structure effect and intensity effect in that regime was getting worse. After 2000, in the high oil price period, the structure effect and intensity effect is getting better.

• Journal of the Korean Solar Energy Society
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• v.33 no.1
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• pp.32-39
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• 2013

Effects of Weibull shape parameter, k, on capacity factors of wind turbines were investigated. Wind distributions with mean wind speeds of 5 m/s, 6 m/s, 7 m/s and 8 m/s were simulated and used to estimate the annual energy productions and capacity factors of a 2MW wind turbine for various Weibull shape parameters. It was found from the study that the capacity factors of wind turbines are much affected by Weibull shape parameters. When the annual mean wind speed at the hub height of a wind turbine was about 7 m/s, and the air density was assumed to be 1.225 $kg/m^3$, the maximum capacity factor of a 2 MW wind turbine having a rated wind speed of 13 m/s was found to occur with the shape parameter of 2. It was also found that as the mean wind speed increased, the Weibull k parameter which yielded the maximum capacity factor increased. The simulated results were also validated by predictions of capacity factors of wind turbines using wind data measured in complex terrain.

• Journal of Nutrition and Health
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• v.46 no.4
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• pp.346-356
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• 2013

This study investigated the daily physical activity level, energy expenditure, energy balance, and body composition and their relationship with university students. The participants were 130 male students ($19.5{\pm}0.5$ yrs) and 139 female students ($19.5{\pm}0.3$ yrs) at a university in Chungnam province. Physical activity level was evaluated by an equation based on 24 hr-activity record and dietary nutrient intake was evaluated using the food record method during a three-day period consisting of two week days and one weekend. Body composition was measured using Inbody 430 (Biospace Co., Cheonan, Korea). As a result, mean body mass index (BMI) of subjects indicated that they had normal weight, however mean body fat ratio was $19.1{\pm}5.4%$ for males and $28.4{\pm}5.0%$ for females, indicating that they had higher than normal weight. Daily mean physical activity level was 1.55 for males and 1.47 for females, which was regarded as 'low active', respectively. Females had more light activity than males (p<0.01). Daily mean energy expenditure was $2,803.5{\pm}788.9$ kcal/d for males and $1,915.4{\pm}510.2$ kcal/d for females (p<0.001). Daily mean dietary energy intake was $2,327.0{\pm}562.5$ kcal/d for males and $1,802.1{\pm}523.6/d$ for females (p<0.001), and daily mean energy balance was $-476.5{\pm}955.9$ kcal/d for males and $-113.3{\pm}728.1$ kcal/d for females (p<0.01). Daily mean dietary intake of protein, vitamins, and minerals, except Ca, satisfied recommended nutrient intake. Daily energy expenditure was positively related to body weight (p<0.01), BMI (p<0.01), and fat free mass ratio (p<0.05), but was negatively related to body fat ratio (p<0.01). In conclusion, subjects had a negative energy balance and low physical activity. They had a normal weight by BMI but had a more fat than normal weight by body fat ratio. This appears to be related to their low physical activity. Thus, nutrition education should be provided for university students in order to increase their physical activity for maintenance of normal weight by body composition and health promotion.

• Journal of Nutrition and Health
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• v.20 no.2
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• pp.90-103
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• 1987

A study was conducted to measure nitrogen intake and excretion in young korean women on their normal diet and leading normal activity level. Dietary survey by food record, fecal and urinary samples were collected for 3 days in 19 healthy female college students in Korea. On one of the 3 days, duplicate of one-day diet was collected from each subjects. Mean daily intakes of energy and protein were calculated from food recorded. Duplicate diet samples and pooled fecal samples were analyzed for N content. Pooled urine samples were analyzed for total N, urea N, and creatinine content. Apparent N absorption, apparent N balance and urea N/creatinine N were calculated to evaluate protein nutritional status. The results obtained are summarized as following ; 1) Accordingly to food record, mean daily intakes of energy, protein, carbohydrate and far were 1535.2 $\pm$53.78Kcal, 55.95$\pm$2.97g(total nitrogen 8.95$\pm$0.45g), 254.13$\pm$10.31g and 39.24$\pm$2.76 g, providing 14.6%, 66.2%, 19.2% of total energy respectively. 2) Nitrogen intake by chemical analysis was 7.16$\pm$0.31g/day (protein 44.75$\pm$1.94kg/day) providing 82.39$\pm$4.58% of nitrogen intake by food record. The difference of total nitrogen intake between food record and chemical analysis in diets was significant(p<0.05). 3) Mean daily fecal nitrogen excretion was 1.38$\pm$0.10g and then mean apparent digesbility of protein was 80.53$\pm$5.21%. 4) Mean daily urinary nitrogen excretion, urea N excretion and creatinine excretion were 6.03$\pm$0.30g, 4.52$\pm$0.22g, and 0.88$\pm$0.04g respectively. Urinary urea nitrogen was 75.2$\pm$1.38% of total urinary nitrogen excretion and urinary nitrogen was 85.4$\pm$3.56% of total nitrogen intake by chemical analysis. 5) Mean urea N/creatinine N ration was 14.01$\pm$0.77. 6) Mean nitrogen balance was -0.244$\pm$0.33g/day. From the above results, it is concluded that the subjects in this study seem to be in marginal protein nutritional status and therefore should increase dietary protein intake.

• Structural Engineering and Mechanics
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• v.63 no.1
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• pp.23-35
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• 2017

A nonlinear static procedure considering work-energy principle and global failure mechanism to estimate base shears of reinforced concrete (RC) frame-type structures is presented. The relative energy equation comprising of elastic vibrational energy, plastic strain energy and seismic input energy is obtained. The input energy is modified with a factor depending on damping ratio and ductility, and the energy that contributes to damage is obtained. The plastic energy is decreased with a factor to consider the reduced hysteretic behavior of RC members. Given the pre-selected failure mechanism, the modified energy balance equality is written using various approximations for modification factors of input energy and plastic energy in scientific literature. External work done by the design lateral forces distributed to story levels in accordance with Turkish Seismic Design Code is calculated considering the target plastic drift. Equating the plastic energy obtained from energy balance to external work done by the equivalent inertia forces considering, a total of 16 energy-based base shears for each frame are derived considering different combinations of modification factors. Ductility related parameters of modification factors are determined from pushover analysis. Relative input energy of multi degree of freedom (MDOF) system is approximated by using the modal-energy-decomposition approach. Energy-based design base shears are compared with those obtained from nonlinear time history (NLTH) analysis using recorded accelerograms. It is found that some of the energy-based base shears are in reasonable agreement with the mean base shear obtained from NLTH analysis.