• Journal of Biosystems Engineering
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• 제31권1호
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• pp.33-38
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• 2006

This work was conducted to find the operating characteristics of an efficient wet grinding system designed to obtain fine rice husk ash powder. Once the rice husk was combusted and the thermal energy was recovered from the furnace, the ash was fed and pulverized in the grinding system resulting a fine powder to be used as a supplementary adding material to the portland cement. Grinding time (15, 30, 45 min), impeller speed (250, 500, 750 rpm), and mixed ratio (6.7, 8.4, 11.l, 20.9) were three operating factors examined for the performance of a wet-type stirred ball mill grinding system. For the operating conditions employed, mean diameter of fine ash powder, specific energy input, and grinding energy efficiency were in the range of $2.83{\sim}9.58{\mu}m,\;0.5{\sim}6.73kWh/kg,\;and\;0.51{\sim}3.27m^2/Wh$, respectively. With the wet-type stirred ball mill grinding system used in this study, the grinding energy efficiency decreased with the increase in total grinding time, impeller speed, and mixed ratio. The difference in specific surface area of powder linearly increased with logarithm in total number of impeller revolution and the grinding energy efficiency linearly decreased. Grinding time of 45 min, impeller speed of 500 rpm, and mixed ratio of 6.7 were chosen as the best operating condition. At this condition, mean particle diameter of the fine ash, grinding energy efficiency, grinding throughput, and specific energy input were $2.84{\mu}m,\;2.28m^2/Wh,\;0.17kg/h$, and 2.03kWh/kg, respectively. Wet fine grinding which generates no fly dust causing pollution and makes continuous operation easy, is appeared to be a promising solution to the automatization of rice husk ash grinding process.

• 설비공학논문집
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• 제27권3호
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• pp.128-136
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• 2015

Reducing the building energy consumption has become one of the most important issues. However, the current engineering and technological involvement in energy analysis has been relatively low in the existing buildings. In the existing buildings, end-use analysis must be accompanied to calculate the exact amount in energy savings and such analysis should be conducted based on the energy billing data or measurement data by calibration process. Mostly, detailed energy simulation programs have been proposed for the analysis but, it is difficult to utilize them due to realistic problems. In this paper, we developed an end-use analysis tool that have input function for energy audit data and two case studies were conducted in the real-life office buildings located in Seoul, Korea. Mean Bias Error (MBE) and Coefficient of Variation of Root-Mean- Squreaed-Error (CV(RMSE)) are used for the criteria of comparison. Each index was calculated by using monthly utility bills of electricity and gas consumption. Results showed that MBE and CV (RMSE) represented with acceptable values of -0.1% and 5.7% respectively.

• 대한지역사회영양학회지
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• 제24권3호
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• pp.223-231
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• 2019

Objectives: This study evaluated dietary intakes of total fat and fatty acids among the Korean adult population. Methods: This cross-sectional study used the 2016-2017 Korea National Health and Nutrition Examination Survey data. A total of 10,772 subjects aged ${\geq}19y$ for which dietary data were available were selected. Data pertaining to energy and nutrient intakes were obtained by a 24-h recall method. Total fat and fatty acids intakes were evaluated based on the Acceptable Macronutrient Distribution Ranges (AMDR) of 2015 Dietary Reference Intakes for Koreans by sex and age groups. All statistical analyses accounted for the complex sampling design effect and sampling weights. Results: The mean intakes of energy and total fat were 1,952 kcal (95% CI: 1928-1977) and 46.1 g (45.2-47.1), respectively, and about 21% of the energy was obtained from fat in this study population (21.7% in men and 20.2% in women). The mean percentages of energy from saturated, monounsaturated, and polyunsaturated fatty acids were 6.4%, 6.7%, and 5.2%, respectively. About 18% of adults exceeded the AMDR for fat (30% of energy), whereas 37.6% exceeded the AMDR for saturated fatty acids (7% of energy). The proportions of subjects who consumed more than the AMDR for fat and saturated fatty acids decreased across age groups in both sexes. Among young adults (19-29 y), about 63% of the subjects obtained ${\geq}7%$ of their energy from saturated fatty acids. About 61% of older adults obtained less than 15% of their energy from total fat. Conclusions: Increased intake of fat energy was prominent in saturated fatty acids. Our findings suggest current information on total fat and fatty acids intakes in Korean adults and can be used to provide dietary guidelines for the improvement of public health.

• 한국태양에너지학회 논문집
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• 제39권3호
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• pp.59-66
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• 2019

New and renewable energy forecasts are key technology to reduce the annual operating cost of new and renewable facilities, and accuracy of forecasts is paramount. In this study, we intend to build a model for the prediction of short-term solar power generation for 1 hour to 3 hours. To this end, this study applied two time series technique, ARIMA model without considering seasonality and SARIMA model with considering seasonality, comparing which technique has better predictive accuracy. Comparing predicted errors by MAE measures of solar power generation for 1 hour to 3 hours at four locations, the solar power forecast model using ARIMA was better in terms of predictive accuracy than the solar power forecast model using SARIMA. On the other hand, a comparison of predicted error by RMSE measures resulted in a solar power forecast model using SARIMA being better in terms of predictive accuracy than a solar power forecast model using ARIMA.

• The Korean Journal of Physiology
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• 제5권2호
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• pp.15-27
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• 1971

Physiological analysis of the physical exercise was made on 9 subjects performing mountain climbing. The course between two points (256 and 516 meters altitude) was 1,300 meters in distance and difference of vertical height was 260 meters making the mean grade of 20%. In the field, the heart rates during uphill or downhill walk were recorded by EKG radio-telemetry. In the laboratory, oxygen consumption was obtained by the recorded heart rates, using individual heart rate vs oxygen consumption diagram obtained by treadmill test. the following results were obtained. 1. Uphill walk time was 36.5 minutes, and during this period the mean heart rate was 149.0 heats/min and peak heart rate was 169.2 beats/min. The total heart beats during the uphill walk was 5.433 beats. 2. The ratio of individual mean heart rate during the uphill walk to the maximal heart rate distributed between 66.6% and 98.3%, and the mean of the total group was 83.1%. The ratio of peak heart rate of uphill walk to the maximal heart rate was 94.5% in the group. Thus uphill walk of a 20% grade mountain course was an exhaustive exercise. 3. Oxygen consumption during uphill walk was 2.22 l/min (ranged between 1.79 and 2.70 l/min) and the ratio of this to the resting oxygen consumption was 8.31. The peak value of oxygen consumption during uphill walk was 2.73 l/min and the ratio of this to the resting oxygen consumption was 10.39. 4. Energy expenditure during uphill walk showed a mean of 11.1 kcal/min and the peak expenditure rate was 13.6 kcal/min. The total energy expenditure during 36.5 minutes of uphill walk was 396 kcal. 5. In downhill walk, the time was 31.7 minutes, mean heart rate was 118.4 (ranged between 100.1 and 142.7) beats/min, and the peak heart rate was only 129.4 beats/min. The ratio of mean heart rate to the maximal heart rate was 66.3%. Total heart beats during downhill walk was 3,710 beats. The ratio of downhill oxygen consumption to the resting consumption was 5.70. The rate of energy expenditure was 7.5 kcal/min, and the total onery expenditure during the 31.7 minutes of downhill walk was 228 kcal. 6. The effect of training was manifest in the uphill walk and not in the downhill walk. After training in mountain course walk, i) the uphill time was shortened, ii) mean heart rate increased, iii) time vs heart rate curve became smooth and showed less frequent zig-zag, i.e., the depth of trough on the curve decreased and the magnitude was less than 10 beats. In non-trained subject the depth of trough on the curve was greater than 50 beats and appeared more frequently. 7. Mountain climbing is a good health promotion exercise. For the promotion of health the reasonable amount of uphill mountain walk exercise in a 20% grade course is a walk for 40 or 50 minutes duration once a week.

• 자원ㆍ환경경제연구
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• 제24권1호
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• pp.189-224
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• 2015

본 연구는 온실가스 감축목표 업종체계에 따라 산업 부문을 18개 세부 업종으로 구분하여 2004년부터 2011년까지의 에너지 소비량과 온실가스 배출량 변화에 대해 로그평균디비지아지수(Log Mean Divisia Index) 분해분석을 하였다. 산업 부문 에너지 소비량의 증가는 생산효과와 에너지원단위 효과에 기인한 것으로 나타났으며, 구조 효과는 에너지 소비량 감소에 기여하였다. 온실가스 배출량 변화에 있어서도 구조 효과만이 온실가스 배출 감소에 기여한 것으로 나타났다. 하지만 세부 업종별로는 에너지 소비 및 온실가스 배출량에 미치는 요인별 효과가 서로 달랐다. 특히 본 연구에서는 비금속, 조립금속 등 집계된 업종을 기준으로 분석한 기존 연구들과 달리 이들을 감축목표 업종체계에 따라 세분화하여 분석하였다. 분석 결과 비금속의 세부 업종인 시멘트와 조립금속의 세부 업종인 기계업종은 각각 비금속, 조립금속과 서로 다른 분석 결과를 보였다. 따라서 비금속 및 조립금속에 대한 분해분석 결과를 세부 업종들에게 일률적으로 적용할 경우 정책적 오류에 직면할 가능성이 크므로 세부 업종별로 차별화된 정책 대응이 필요하다.

• Journal of Nutrition and Health
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• 제24권2호
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• pp.132-141
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• 1991

The purpose of this study was to choose the assessment method of usual energy in take for epidemiological study. Energy intakes of 30 female college students estimated by frequency questionnaires and energy balance method were compared with that obtained by dietary record. The results are summarized as follows. Assessment of mean energy intakes by dietary record frequency questionnaires energy balance method were 156.2Kcal, 1517Kcal, 1878.0Kcal respectively. There was no significant difference between energy intake by dietary record and that by frequency questionnaire. Frequency questionnaire covers 4 weeks energy intake and it can be substituted for dietary record. Although energy intake by energy balance method was significantly different from that obtained by dietary record it shows high correlation with anthropometric and obesity indices and energy expenditure of the subjects.

• Preventive Nutrition and Food Science
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• 제14권4호
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• pp.343-348
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• 2009

This study sought to determine changes in self-selected diets in response to a high energy tomato pasta entree. Thirty men, mostly African-American, who were diagnosed with prostate cancer and also scheduled for prostatectomy were enrolled in the study. Dietary intakes were obtained by 24 hr diet recall for 3 days before the intervention and 3 days in week 2 during the intervention. Tomato pasta entrees were formulated to contain 30 mg of lycopene with roughly the same macronutrient composition and averaged 771 kcal/entree. Mean adherence to lycopene dose was 82% and, days when the entree was consumed, the mean adherence to lycopen was 90%. Lycopene intake in their self-selected diet decreased from 5 to 1 mg/day which lowered the exposure to lycopene, planned during the intervention. The men were able to decompensate for most of the added energy to their diet, but there was still a mean increase in total intake of 242 kcal/day (p=0.04), which did not result in weight gain over the short period of the study. There were no significant changes in the percent of energy from protein, fat or carbohydrates, but dietary cholesterol increased from 341 to 472 mg/day (p=0.0002). Mean intakes of vitamins A and C, and folate were not significantly different and were above the EAR. Vitamin E intake decreased, but, because of the variance in intake, the decrease was not statistically significant. Possible deterioration of diet quality should be a consideration when recommending whole food interventions for the prevention of chronic disease or the amelioration of physiological dysfunction.

• 대한지역사회영양학회지
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• 제10권6호
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• pp.880-891
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• 2005

The purpose of this study was to investigate nutrients intakes and nutritional quality of Adults and Elderly People in an island area (Wando). A three-day dietary intakes survey, using a 24 hour recall method was obtained from 187 subjects aged 46 to 84 (mean age 65.3) living in an island area (Wando). Nutient intakes were analyzed using CAN-Pro soft program and compared to Korean RDA. The quality of nutrients was assessed by analyzing nutrient adequacy ratio (NAR), mean adequacy ratio (MAR), and index of nutritional quality (INQ). The average daily mean energy intakes were 1869.0 kcal for males and 1943.9 kcal for females, respectively. Daily intakes of protein for males and females were 28.0 and 30.4 g and those of fat were 31.5 and 28.51 g, respectively. Nutrient consumed below $75\%$ of Korean RDA was protein, vitamin A, Ca and Zn in both males and females. Average CPF ratio of males and females were 78.8 : 6.0 : 15.1 and 80.0 : 6.4 13.4, respectively. Energy intake ratio from protein was significantly higher in over 60 years males. Carbohydrate dependency decreased with age. Protein dependency increased with age. Nutrient adequacy ratio (NAR) of energy, protein vitamin A and vitamin E were increased with age in males. The mean adequacy ratio (MAR), an index of overall dietary quality, were not significantly different by age group. Average MAR for males and females was 0.77 and 0.78, respectively. The index of nutritional quality (INQ) showed the tendency to decrease with age. Especially, there were significantly decreases in INQ of all nutrients, except protein, with age. Based on these results, it is evident that people in the island area did not consume enough nutrients. Specially, dietary intake of protein, vitamin A, vitamin E, and Ca were not adequate. (Korean J Community Nutrition 10(6) : $880\∼891$, 2005)

• Journal of Nutrition and Health
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• 제23권1호
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• pp.25-36
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• 1990

This study was carried out to investigate Mg status and the relationship between dietary Mg the blood pressure in 30 healthy women, 26 to 57 year of age, living in rural area of Korea. Dietary intake of the subjects on self-selected diet were recorded. Duplicated food sample and 24-hour urine samples were collected for 3 days. Mean daily dietary Mg intake levels were determined by chemical analysis of duplicated food samples and mean daily urinary Mg excretion was measured from urine samples. Fasting serum Mg levels of each subjects was measured on the 3rd day of the survey. The results were as following: 1) The mean daily intakes of energy, protein were 1770.36㎉ and 55.55g, respectively. Carbohydrare, fat and protein supplied 77.1%, 10.4% and 12.5% of total energy intake. 2) The dietary Mg showed positive correlations with carbohydrate(P<0.05), vitamin A and vitamin B2(P<0.01), energy, Ca, P, fiber, vitamin B1 and niacin(P<0.001), but negative correlation with SBP(P<0.05). 3) The daily mean intake of Mg was 259.07$\pm$74.54mg and the urinary excretion of Mg was 75.48$\pm$33.14mg which was 29.5% of the dietary intake of Mg. And there was no significance between the dietary intake and the urinary excretion of Mg. 4) The dietary fiber showed negative correlations with SBP and DBP(P<0.05). 5) The serum and urinary concentrations of Mg were normal range and the serum Mg showed negative correlation with dietary vitamin C(P<0.05, r=-0.3655). It was concluded that the dietary Mg level of Korean rural women consuming self-selected diets was lower than that of RDA of American women but higher than that of RDA of Canadian. And the dietary intake levels of Mg and fiber, which are contained mostly in cereals and vegetables are useful to prevent hypertention.