• Child Health Nursing Research
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• v.25 no.1
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• pp.48-55
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• 2019

Purpose: This study aimed to investigate the status of caffeine-containing energy drink consumption among Korean nursing students and to identify associated psychological factors. Methods: In total, 187 Korean nursing students participated in this cross-sectional study. A self-administered questionnaire was used to identify participants' general characteristics and psychosocial factors (self-esteem, academic stress, depression, and college adjustment) associated with energy drink consumption. Data were analyzed with SPSS using descriptive statistics, the $x^2$ test, the t-test, and logistic regression. Results: More than two-thirds (73.3%) of the participants had consumed energy drinks. Among the investigated psychological factors, depression appeared to most strongly influence energy drink consumption behaviors in this population. Conclusion: The consumption of caffeine-containing energy drinks was found to be common among nursing students preparing to become health care professionals; depressed nursing students were more likely to have consumed energy drinks than non-depressed students. Nursing educators should emphasize the early detection of unhealthy beverage consumption habits and provide appropriate education to enhance healthy behaviors in future health care professionals.

• Journal of Satellite, Information and Communications
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• v.11 no.2
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• pp.42-47
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• 2016

Due to advances such as photovoltaic power generation and energy storage system, energy self-consumption smart home system in which energy management system is built and energy is generated in house has been actively researched. In particular, due to the instability of the grid after the Fukushima nuclear accident, home system in which generating electricity from photovoltaic, storing and using it in energy storage system was commercialized in Japan. While subsidizing renewable energy projects through a combination of solar and energy storage systems in North America and Europe has expanded home installation. In this paper, we describe development of self-consumption smart home system which is connecting photovoltaic system and energy storage system in home area network and operating it based on real-time price. We implemented automated self-consumption home in which optimizing the use of energy from the power grid with minimal user's intervention.

• The Korean Journal of Food And Nutrition
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• v.29 no.6
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• pp.899-910
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• 2016

The purpose of this study was to determine factors related to the consumption of energy drinks among male and female high school students in Daejeon. The research data, derived from the self-administered questionnaire method, was collected from 664 students in fifteen high schools during the spring of 2016. A total of 542 complete questionnaires were analyzed (response rate: 79.8%). Approximately 73% of the students self-reported having consumed energy drinks, with a greater percentage of male (as opposed to female) students self-reporting as having done so. The most common reasons given for the consumption of energy drinks were to stay awake (54.8%), the good taste of the drink (28.0%), to concentrate during studying (17.2%), and to relieve fatigue (16.9%). The adverse effects were palpitation (59.3%), insomnia (35.6%), and experiencing difficulty in waking up (30.5%). More than two in three (67.8%) students who experienced adverse effects still consumed energy drinks. The average level of health consciousness was lower than 3 out of 5 points. The results of the logistic regression analyses indicated a positive relationship between monthly allowance (OR=1.01 for male and female students) and the consumption of energy drinks by both male and female students. Among the male students, freshmen (OR=0.23) were less likely to have consumed energy drinks than juniors. Male students' sleeping hours (OR=0.65) and perceived school life satisfaction scores (OR=0.63) were negatively associated with the consumption of energy drinks. In the case of female students, study hours (OR=0.83) and energy drinks consumption were negatively related. These factors affecting energy drinks consumption could be considered in the development of dietary education programs aimed at protecting high school students from the adverse health impacts of energy drinks.

• Current Photovoltaic Research
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• v.11 no.4
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• pp.134-143
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• 2023

Efforts are being made to respond to global warming. Interest in and demand for the private sector-led RE100 campaign is also increasing. Self-built solar power generation, one of the implementation tools for RE100, is not expanding. However, it can be an economical means of implementation in the long run. In this study, we intend to analyze the impact on the optimal ratio of self-solar power generation using HOMER simulation. OPR defines the optimal solar power generation ratio and looks into what changes there are in the optimal solar power ratio when self-power consumption increases and external power purchase price changes. As a result, the optimal rate of self-solar power generation has a low impact even if self-power consumption increases. As the external power unit price increases, the optimal ratio increases, and at a power unit price of 100 KRW/kWh, OPR is 24%; at 200 KRW/kWh OPR is 31%; and at 300 KRW/kWh OPR is 34%. This shows that the electricity price replaced during the life cycle has a high impact on the economic feasibility of solar power generation. However, when the external power unit price reached a certain level, the increase in OPR decreased. This shows that it is difficult for domestic companies to achieve RE100 based on the economic feasibility of solar energy alone. Therefore, efforts are needed to supply renewable energy in the public sector.

• Korean Journal of Poultry Science
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• v.21 no.2
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• pp.101-111
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• 1994

From the observations of dietary self-selection by growing pullets, step-up protein or reverse protein and single-stage low protein pullet feeding systems were developed. They offered another pullet feeding concept that appears to control the body weight effectively and to reduce the consumption of feed and nutrients without impairment of subsequent laying performance. It is obvious from the feed and nutrient consumption pattern of layers fed diets for self-selection of energy, protein and calcium that they have a daily cyclic requirement rather than a constant requirement for nutrients. It seems that a practical self-selective feeding system is needed to meet the daily cyclic requirement for nutrients without consuming an excess of energy and protein at certain times of the day as compared to the complete or single diet where layers have to consume extra energy and protein in the afternoon when they have a specific appetite mainly for calcium.

• KIEAE Journal
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• v.12 no.4
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• pp.21-30
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• 2012

This study aims to set up Energy self-sufficiency urban planning system responding climate change by reducing fossil energy consumption and carbon emission, and to suggest effective application method. This study has 3 levels. First, it defines energy self-sufficient city responding climate change theoretically. Second, it set up planning system of Energy Self-sufficient city responding climate change. Third, ANP method was applied to introduce priority of application according to relative importance of planning section. As ANP method has to construct network to show interrelation among elements, 1st questionnaire survey was carried out to figure out interrelation. 2nd questionnaire survey introduced to judge relative importance of planning aspects and sections. In conclusion, this study shows interrelation among planning sections. By considering the relative importance, Energy environment and Energy consumption was derived as important planning aspects, and Architecture, Landuse, and Production of renewable energy was estimated as s important planning elements.

• Journal of Electrochemical Science and Technology
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• v.9 no.1
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• pp.37-43
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• 2018

In order to improve current efficiency and decrease energy consumption in the electrosynthesis of ammonium persulfate, electrolytic properties of four cation exchange membranes, namely, the $JCM-II^{(R)}$ membrane, $Nafion^{(R)}$ 324 membrane CMI-$7000^{(R)}$ membrane and a self-made perfluorosulfonic ion exchange membrane (PGN membrane) were investigated using a sintered platinized titanium anode and a Pb-Sb-Sn alloy cathode in a self-made electrolytic cell. The effect of cell voltage and electrolyte flow rate on the current efficiency and the energy consumption were investigated. The results indicated that the PGN membrane could improve current efficiency to 94.85% and decrease energy consumption to $1119kWh\;t^{-1}$ (energy consumption per ton of the ammonium persulfate generated) under the optimal operating conditions and the highest current efficiency of the $JCM-II^{(R)}$ membrane, $Nafion^{(R)}$ 324 membrane and CMI-$7000^{(R)}$ membrane were 80.73%, 77.76% and 73.22% with their lowest energy consumption of $1323kWh\;t^{-1}$, $1539kWh\;t^{-1}$ and $2256kWh\;t^{-1}$, respectively. The PGN membrane has the advantages of high current efficiency and energy power consumption and has sufficient mechanical strength with the reinforced mesh. Therefore the PGN membrane will has good value in popularization in the industrial electrosynthesis of ammonium persulfate in the future.

• Journal of the Korean Solar Energy Society
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• v.39 no.6
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• pp.137-151
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• 2019

This study estimated the available renewable market potential based on Levelized Cost Of Electricity and then assessed the renewable derived energy self-sufficiency for the unit of local government in South Korea. To calculate energy self-sufficiency, 1 km gridded market renewable generation and local government scale of final energy consumption data were used based on the market costs and statistics for the recent three years. The results showed that the estimated renewable market potentials were 689 TWh (Install capacity 829 GW, 128 Mtoe), which can cover 120% of power consumption. 55% of municipalities can fully replace the existing energy consumption with renewable energy generation and the surplus generation can compensate for the rest area through electricity trade. However, it was confirmed that, currently, 47% of the local governments do not fully consider all renewable energy sources such as wind, hydro and geothermal in establishing 100% renewable energy. The results of this study suggest that energy planning is decentralized, and this will greatly contribute to the establishment of power planning of local governments and close the information gap between the central government, the local governments, and the public.

• Advances in Energy Research
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• v.2 no.1
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• pp.11-20
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• 2014

This paper examines the climatic and technical feasibilities of zero energy buildings in Seoul, Shanghai, Singapore and Riyadh. Annual and seasonal energy demands of office buildings of various scales in the above cities were compared. Using optimally tilted rooftop PV panels, solar energy production potentials of the buildings were estimated. Based on the estimates of onsite renewable energy production and building energy consumption, the energy self-sufficiencies of the test buildings were assessed. The economic feasibilities of the PV systems in the four locations were analyzed. Strategies for achieving zero energy buildings are suggested.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.12B
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• pp.1028-1036
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• 2006

Energy conservation is an important issue in wireless networks, especially for self-organized, low power, low data-rate impulse-radio ultra-wideband (IR-UWB) networks, where every node is a battery-driven device. To conserve energy, it is necessary to turn node into sleep state when no data exist. This paper addresses the energy consumption analysis of Direct-Sequence (DS) versus Time-Hopping (TH) multiple accesses and two kinds of sleeping protocols (slotted and unslotted) in PHY-MAC for Un networks. We introduce an analytical model for energy consumption or a node in both TH and DS multiple accesses and evaluate the energy consumption comparison between them and also the performance of the proposed sleeping protocols. Simulation results show that the energy consumption per packet of DS case is less than TH case and for slotted sleeping is less than that of unslotted one for bursty load case, but with respect to the load access delay unslotted one consumes less energy, that maximize node lifetime.