• Journal of the Korean Society of Food Culture
• /
• v.14 no.1
• /
• pp.1-15
• /
• 1999

A survey was conducted in 591 college students using 8 different cafeterias serving 31 meals. The information was obtained about the name and amount of dishes they consumed from the menu offered by college foodservice. Mean nutrient contents per meal in offered menu were higher than 1/3 of RDA for their age, sex in offered menu. The mean energy content was 466kcal from rice, 113kcal from soup, 141kcal from side dish and 21kcal from kimchi. When side dishes were classified by cooking methods, side dishes using grilling, frying, roasting methods had high energy content and fat percent above 200kcal, 40% per dish. By main ingredients, side dishes with animal food were higher energy than with plant food. Students consumed 94% of the energy provided in offered menu. When compared to proportion of foods consumed by sex, there was 43% of female and 22% of male consumed less than half in soup and 31% of female and 12% of male in kimchi. The most prevalent menu patterns of subjects included rice, soup, 2 side dishes, kimchi and were the same in both sexes. Mean energy intakes per meal were 989kcal for males and 842kcal for females which were enough to meet 1/3 of RDA for their age and sex. Most nutrient intake except fat and vitamin B1 were higher in set menu than in cafeteria. Nutrient adequacy ratio(NAR) were above 0.9 except calcium and vitamin A. The mean energy intake was 542kcal from rice, 70kcal from soup, 164kcal from side dish and 20kcal from kimchi. In conclusion, intake of most of the nutrients of students obtained from males in college foodservice were sufficient but calcium intake was insufficient and fat content was above 20% of energy. High fat consumption was due to side dishes from frying, grilling, roasting with animal food. To provide desirable meals in college foodservice, use of fat in cooking must be decreased.

• Journal of the Korean Solar Energy Society
• /
• v.25 no.1
• /
• pp.79-86
• /
• 2005

The external conditions for estimating dynamic wind loads of wind turbines, such as the turbulence, the extreme wind, the mean velocity gradients and the flow angles, are simulated over GangWon Wind Energy Test Field placed in one of the most complex terrain in Korea. Reference meteorological data has been gathered at a height of 30m from 2003 to 2004 with a ultrasonic anemometer. The absolute value of the spectral energy are simulated and the verification of this prediction has been carried out with comparing to the experimental data. The most desirable place for constructing new wind turbine are resulted as Point 2 and Point 3 due to the lower value of Turbulence Intensity and the higher value of wind resource relatively.

• Korean Journal of Human Ecology
• /
• v.3 no.1
• /
• pp.15-24
• /
• 2000

This study was performed to assess the extent of dietary diversity and nutrient intakes of Korean child-bearing women and to investigate the relationships between dietary diversity indices and nutrient intakes. A total of 91 women aged 18 to 48 years old participated. They were divided into four groups by age 15 subjects in teens, 20 in twenties. 32 in thirties and 24 in forties. Mean energy intake was 1638${\pm}$471㎉/day and it was low as 81.4% of the Korean RDA for energy. Mean intakes of folate, calcium and iron were also low as 81.7%. 72.6% and 57.2% of the RDAs. On the other hand, protein, vitamin A, thiamin, riboflavin and vitamin C were consumed close to or above the RDAs. It was obvious that the subjects in teens and twenties took less all of the nutrients as well as energy than those In thirties and forties. Mean nutrient adequacy ratio( MNAR) was 0.77 and showed a trend to raise with increasing age. Thus MNAR of the teens was the lowest and that of the forties was the highest among the age groups. The results in this study support the previous findings that nutrient intakes of women in teens and twenties were poorer compared to those in thirties and forties. Mean dietary diversity score( DDS) . dietary variety score(DVS) and dietary frequency score( DFS) were 4.1. 11.6 and 14.7. respectively. DVS and DFS of the teens and twenties were lower than those in thirties and forties. DDS significantly correlated to the intakes of energy and calcium only, however, DVS and DFS had significant relationships to the intakes of all nutrients. The MNAR significantly related to DVS and DFS. but not DDS. In conclusion, the intakes of energy, folate. calcium and iron of child-bearing women were not sufficient and their nutrient adequacy highly correlated with dietary diversity. It indicates that to consume various foods helps to enhance the nutritional status.

• Wind and Structures
• /
• v.18 no.6
• /
• pp.619-631
• /
• 2014

This paper proposes new criteria to fix hidden neuron in Multilayer Perceptron Networks for wind speed prediction in renewable energy systems. To fix hidden neurons, 101 various criteria are examined based on the estimated mean squared error. The results show that proposed approach performs better in terms of testing mean squared errors. The convergence analysis is performed for the various proposed criteria. Mean squared error is used as an indicator for fixing neuron in hidden layer. The proposed criteria find solution to fix hidden neuron in neural networks. This approach is effective, accurate with minimal error than other approaches. The significance of increasing the number of hidden neurons in multilayer perceptron network is also analyzed using these criteria. To verify the effectiveness of the proposed method, simulations were conducted on real time wind data. Simulations infer that with minimum mean squared error the proposed approach can be used for wind speed prediction in renewable energy systems.

• Korean Journal of Mathematics
• /
• v.4 no.2
• /
• pp.141-148
• /
• 1996

• Proceedings of the KIEE Conference
• /
• 2001.07e
• /
• pp.76-79
• /
• 2001

Energy distribution function in $SiH_4$ has been analysed over the E/N range $0.5{\sim}300Td$ and Pressure value 0.5, 1.0, 2.5 Torr by a two-term approximation Boltzmann equation method and by a Monte Carlo simulation. The motion has been calculated to give swarm parameters for the electron drift velocity, diffusion coefficient, electron ionization, mean energy and the electron energy distribution function. The electron energy distribution function has been analysed in $SiH_4$ at E/N=30, 50Td for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.10
• /
• pp.177-182
• /
• 2003

The front-end side members of automobiles absorb most of the energy in a case of front-end collision. The front-end side members are required to have a high stiffness together with easiness to collapse sequentially to absorb more impact energy. The axial static collapse test (5mm/min) was conducted by using UTM for form different types of members which have different cross section shapes; single hat, single cap, double cap, and double hat. The single hat shaped section member has the typical standard section, which the double hat shape section has a symmetry in the center to have more stiffness. As a result of the test, the energy absorbing characteristic was analyzed for different section shapes. It turned out that the change of section shape influence the absorbing energy, the mean collapse load and the maximum collapse load, and the relation between the change of section shape and the collapse mode.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.17 no.1
• /
• pp.86-91
• /
• 2008

The structural members must be designed to control characteristics of energy absorption for protecting passengers in a car accident. Study on collapse characteristics of structural member is currently conducted in parallel with other studies on effective energy absorption capacity of structural members with diverse cross-sectional shapes and various materials. This study concerns the crashworthiness of the widely used vehicle structural members, square thin-walled tubes, which are excellent in the point of the energy absorption capacity. The absorbed energy, mean collapse load and deformation mode were analyzed for side member which absorbs most of the collision energy. To predict and control the energy absorption, controller is designed in consideration of its influence on height, thickness and width ration in this study. The absorbed energy and mean collapse load of square tubes were increased by $15{\sim}20%$ in using the controller, and energy absorbing capability of the specimen was slightly changed by change of the high controller's height.

• 한국태양에너지학회:학술대회논문집
• /
• 2012.03a
• /
• pp.293-298
• /
• 2012

The purpose of this study is performance validation of district heating apartments about heating energy consumption and analysis of energy consumption by unit characteristics. The heating energy consumption of the existing apartments was analyzed and the analyzed results will be used for energy saving technology development and policy making. The heating energy consumption data about total 78 apartment complexes, 56,910 units in Gangnam-Gu, Seoul, Korea were investigated from October, 2010 to April 2011. The analysis results are as follows; The mean heating energy consumption is 98[kWh/m2]. The energy consumption of Apgujung-Dong, Daechi-Dong is higher than that of mean valuse. The energy consumption deviation by deterioration, unit area, core type and regional group is very high. Specially, building deterioration casts a long shadow.

• International Journal of Ocean System Engineering
• /
• v.2 no.1
• /
• pp.50-56
• /
• 2012

This study investigates flow fields and energy dissipation due to regular wave interaction with a perforated vertical breakwater, through velocity data measurement in a two-dimensional wave tank. As the waves propagate through the perforated breakwater, the incoming wave energy is reflected back to the ocean, dissipated due to very turbulent flows near the perforations and inside the chamber, and transmitted through the perforations of the breakwater. This transmitted energy is further reduced due to the presence of the perforated back wall. Hence most of the energy is either reflected or dissipated in the vicinity of the structure, and only a small amount of the incoming wave energy is transmitted through the structure. In this study, particle image velocimetry (PIV) technique was employed to measure two-dimensional instantaneous velocity fields in the vicinity of the structure. Measured velocity data was treated statistically, and used to calculate mean flow fields, turbulence intensity and turbulent kinetic energy. For investigation of the flow pattern, time-averaged mean velocity fields were examined, and discussed using the cross-sections through slot and wall for comparison. Flow fields were obtained and compared for various cases with different regular wave conditions. In addition, turbulent kinetic energy was estimated as an approach to understand energy dissipation near the perforated breakwater. The turbulent kinetic energy was distributed against wave height and wave period to see the dependence on wave conditions.