• 한국학교보건학회지
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• 제31권3호
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• pp.196-202
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• 2018

Purpose: The purpose of this study was to analyze the relationship between physical activity and energy drinks consumption in Korean Adolescents. Methods: This study was a secondary data analysis using statistics from the 2017(13th) Korea Youth Risk Behavior Web-based Survey. The variables used in the study were physical activity, energy drinks consumption and socio-demographic characteristics such as gender, academic achievement, household economic status and weekly allowance. The data were analyzed by $x^2$ test and multinominal logistic regression and the results were presented in percentage. Results: As the number of days engaging in moderate and vigorous physical activities increased, the response that they consume energy drinks 'more than 5 times a week' also increased. The subjects who participated in a 'moderate' or 'high' level of moderate physical activity consumed 1.4 times more energy drinks than those who do not participate in physical activity. And the subjects who engaged in a 'low' or 'moderate' level of vigorous physical activity consumed about 1.3 times more energy drinks than those who don't work out. Conclusion: As the level and intensity of physical activity increased, the number and frequency of energy drinks consumption increased. The results of this study can be used as basic data for intervention programs to reduce energy drinks consumption and promote proper physical activity.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.138.6-138
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• 2001

In recent years, as the battery-powered portable systems such as cellular phone, personal digital assistant (PDA) are widely used, power consumption comes to be a top-priority design concerns. Because those embedded systems become more and more complex than ever and they are operated under severe power and energy constrains, long battery lifetime with a limited energy is very critical. Even though there are various levels of energy optimization techniques, system level techniques are mainly focused on, for their stronger impact on power consumption of the overall system than traditional techniques : circuit level, switch level, architecture level, etc. In this technique, operating system (OS) plays the most important role in the system because it controls ...

• Journal of Power Electronics
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• 제14권3호
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• pp.499-506
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• 2014

This paper proposes a 3 kW single-phase bi-directional multi-level converter for energy storage applications. The proposed topology is based on the H-bridge structure with four switches connected to the DC-link. A simple phase opposition disposition PWM method that requires only one carrier signal is also suggested. The switching sequence to balance the capacitor voltage is considered. The topology can be extended to a nine-level converter or a three-phase system. The operating principle of the proposed converter is verified through a simulation and an experiment.

• 드라이브 ㆍ 컨트롤
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• 제11권3호
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• pp.22-30
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• 2014

In this research, the energy stability level method is used for examining the stable state of Field Robot under effects of swing motion, at particular postures of manipulator, and terrain conditions. The energy stability level is calculated by using the dynamic models of Field Robot, subjected to the concept of equilibrium plane and support boundary. The results, simulated by using computing program for estimating the potential overturning of Field Robot, supply useful predictions of stability analysis for designers and operators.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1031-1035
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• 2008

The importance of the more efficient cogeneration system is emphasized. Also the more clean energy is needed at recent energy system. The cogeneration system using Lean burn engine is more preferred to the system using Rich burn engine because of the electrical efficiency. Although the cogeneration system using Lean burn engine is economically preferred, because of the NOx emission level, the system using Rich burn engine with 3-way catalyst can only be used in Korea. The NOx regulation level is 50ppm at oxygen level 13%. The cogeneration hybrid system is consist of Lean burn gas engine, afterburner, boiler, economizer, DeNOx catalyst, combustion catalyst, absorption chiller, cooling tower and grid connection system. The system was accurately evaluated and the result is following ; 90% total efficiency, below 10ppm NOx, 50ppm CO, 25ppm UHC. The cogeneration hybrid system can meet the NOx level and exhaust gas regulation. It can achieve the clean combustion gas and efficient cogeneration system.

• 조명전기설비학회논문지
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• 제28권6호
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• pp.91-98
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• 2014

For the purpose of designing and applying the optimum surge protection scheme, multi-stage coordinated surge protective device(SPD) system is suitable to successfully fulfill its tasks; first, to divert a large amount of the transient energy, second, to clamp the overvoltage to the level below the withstand impulse voltage of the equipment to be protected. The length of SPD connecting leads shall be as short as possible. Long connecting leads will degrade the protection effect of SPDs. In this paper, the influences of the length of connecting leads on the energy sharing in a coordinated SPD system were investigated experimentally, and the simulation of determining the energy sharing and protection voltage level of each SPD depending on the length of connecting leads was carried out by using P-spice program. It was confirmed that the protection voltage level and energy sharing in coordinated SPD systems are strongly influenced by the length of connecting leads.

• Asian-Australasian Journal of Animal Sciences
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• 제27권1호
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• pp.55-61
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• 2014

Forty-eight Pelibuey${\times}$Katahdin male intact lambs ($23.87{\pm}2.84$ kg) were used in an 84-d feeding trial, with six pens per treatment in a $2{\times}2$ factorial design arrangement. The aim of the study was to evaluate the interaction of two dietary energy levels (3.05 and 2.83 Mcal/kg ME) and two dietary protein levels (17.5% and 14.5%) on growth performance, dietary energetics and carcass traits. The dietary treatments used were: i) High protein-high energy (HP-HE); ii) High protein-low energy (HP-LE); iii) Low protein-high energy (LP-HE), and iv) Low protein-low energy (LP-LE). With a high-energy level, dry matter intake (DMI) values were 6.1% lower in the low-protein diets, while with low-energy, the DMI values did not differ between the dietary protein levels. Energy levels did not influence the final weight and average daily gain (ADG), but resulted in lower DMI values and higher gain efficiencies. No effects of protein level were detected on growth performance. The observed dietary net energy (NE) ratio and observed DMI were closer than expected in all treatments and were not affected by the different treatments. There was an interaction (p<0.03) between energy and protein level for kidney-pelvic and heart fat (KPH), KPH was higher in lambs fed high energy and high protein diet but not in high energy and low protein diet. The KPH was increased (20.2%, p = 0.01) in high-energy diets, while fat thickness was increased (21.7%, p = 0.02) in high-protein diets. Therefore, it is concluded that dietary energy levels play a more important role in feed efficiency than protein levels in finishing lambs with a high-energy diet (>2.80 Mcal/kg ME). Providing a level of protein above 14.5% does not improves growth-performance, dietary energetics or carcass dressing percentage.

• Nuclear Engineering and Technology
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• 제36권1호
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• pp.83-103
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• 2004

The methodological framework of the Level 2 PSA appears to be currently standardized in a formalized fashion, but there have been different opinions on the way the sources of uncertainty are characterized and treated. This is primarily because the Level 2 PSA deals with complex phenomenological processes that are deterministic in nature rather than random processes, and there are no probabilistic models characterizing them clearly. As a result, the probabilistic quantification of the Level 2 PSA CET / APET is often subjected to two sources of uncertainty: (a) incomplete modeling of accident pathways or different predictions for the behavior of phenomenological events and (b) expert-to-expert variation in estimating the occurrence probability of phenomenological events. While a clear definition of the two sources of uncertainty involved in the Level 2 PSA makes it possible to treat an uncertainty in a consistent manner, careless application of these different sources of uncertainty may produce different conclusions in the decision-making process. The primary purpose of this paper is to characterize typical sources of uncertainty that would often be addressed in the Level 2 PSA and to provide a formal guidance for quantifying their impacts on the PSA Level 2 risk results. An additional purpose of this paper is to give a formal approach on how to combine random uncertainties addressed in the Level 1 PSA with subjectivistic uncertainties addressed in the Level 2 PSA.

• Nuclear Engineering and Technology
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• 제48권1호
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• pp.98-113
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• 2016

A reactor vessel level monitoring system measures the water level in a reactor during normal operation and abnormal conditions. A drop in the water level can expose nuclear fuel, which may lead to fuel meltdown and radiation spread in accident conditions. A level monitoring system mainly consists of a sensing line and pressure transmitter. Over a period of time boron sediments or other impurities can clog the line which may degrade the accuracy of the monitoring system. The aim of this study is to determine blockage in a sensing line using the energy of the composite signal. An equivalent Pi circuit model is used to simulate blockages in the sensing line and the system's response is examined under different blockage levels. Composite signals obtained from the model and plant's unblocked and blocked channels are decomposed into six levels of details and approximations using a wavelet filter bank. The percentage of energy is calculated at each level for approximations. It is observed that the percentage of energy reduces as the blockage level in the sensing line increases. The results of the model and operational data are well correlated. Thus, in our opinion variation in the energy levels of approximations can be used as an index to determine the presence and degree of blockage in a sensing line.

• Bulletin of the Korean Chemical Society
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• 제20권12호
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• pp.1493-1500
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• 1999

The electronic transitions from the ground state to low-lying excited states of CF₃OH have been investigated using high level ab initio quantum mechanical techniques. Also the possible photodissociation procedures of CF₃OH have been considered. The highest level employed in this study is TZP CCSD(T) level of theory. The possible four low-lying excited states can result by the excitation of the lone pair electron (n) in oxygen to σ$^*$ molecular orbital in C-O or O-H bond. The vertical transition (n → σ$^*$) energy is predicted to be 220.5 kcal/mol (130 nm) at TZ2P CISD level to theory. The bond dissociation energies of CF₃OH to CF₃O +H and CF₃+OH have been predicted to be 119.5 kcal/mol and 114.1 kcal/mol, respectively, at TZP CCSD level of theory. In addition, the transition state for the unimolecular decomposition of CF₃OH into CF₂O + HF has been examined. The activation energy and energy separation for this decomposition have been computed to be 43.6kcal/mol and 5.0 kcal/mol including zero-point vibrational energy corrections at TZP CCSD(T) level of theory.ed phenols were also estimated.