• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.795-796
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• 2012

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.321-323
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• 2006

The IEEE 802.15.4 uses a CSMA/CA algorithm on access of media. The CSMA/CA algorithm does Random Backoff before the data is transmitted to avoid collisions. The random backoff is a kind of unavoidable delays and introduces the side effect of energy consumptions. To cope with those problems we propose a new media access algorithm, the Priority Based Ordered Media Access (PBOMA) algorithm, which uses different IFSs. The PBOMA algorithm uses Sampling Rate and Beacon Interval to get a different access probability(or IFS). The access probability is higher, the IFS is shorter. Note that The transfer of urgent data uses tone signal to transmit it immediately. The proposed algorithm is expected to reduce the energy consumptions and the delay.

• Journal of Nutrition and Health
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• 제42권4호
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• pp.327-337
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• 2009

University students tend to have various dietary problems including undesirable dietary behaviors, inadequate intakes of nutrients and biased habits of liquid consumption. This study was conducted to find dietary behaviors (n = 357) by questionnaire survey and to examine dietary nutrient intakes (n = 60) and liquid consumption (n = 853) by food record method for 3-days among university students attended in K University of Chungnam province in Korea. Most subjects lived in the dormitory or self-boarding house, and they skipped breakfast most frequently and took breakfast most irregularly among three meals. Dietary mean intakes of energy, Ca, vitamin B2 and folate were lower than the KDRI (37-85%), and those of males were poorer than those of females. Ratios of energy intake among three meals and snacks were not distributed evenly, so the mean energy intake from snacks was higher and that from breakfast was lower than the ideal ratio, respectively. Daily mean consumption of liquid was 1,526.4 mL/d for males and 1,151.5 mL/d for females, and these intakes were more than the KDRI (1,300 mL/d for males and 1,100 mL/d for females). However, their sources of liquid consumption were not desirable because alcohol, soda, juice of fruit or vegetable and beverage mixed with fruit juice and/or vegetable juice were major sources of liquid as well as drinking water. These findings show that university students have poor dietary behaviors including frequent skipping of breakfast, irregularity of meals, inadequate intakes of nutrients and undesirable pattersirablliquid consumption including high portion of alcohol and soda as alliquid source, and these trends were stronger for males than for females. Therefore, we should endeavor to correct their meal problems id ated to dietary behaviors, nutrient intakes and liquid consumptions through nutrition education.

• 한국태양에너지학회 논문집
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• 제34권1호
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• pp.39-47
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• 2014

Solar applications analysis and building energy performance depend on the quality of the solar resource data available. Unfortunately, most of the weather stations do not measure solar radiation data in Korea, as a reason many researchers have studied different solar radiation estimation models and suggested to apply them to various locations in Korea. In addition, they also studied the impact of hourly global solar radiation on energy performance of an office building by comparing the simulated building energy consumptions using four different weather files, one using measured, and three estimated solar radiation from different models, which are Cloud-cover Radiation Model (CRM), Zhang and Huang Model (ZHM), and Meteorological Radiation Model (MRM), and concluded that there was some impact on energy performance of the building due to the using different solar radiation models. However, the result cannot be applied to all other buildings since the simulated office building for that study only used limited building characteristics such as using fixed values of solar heat gain coefficient (SHGC) and window-to-wall ratio (WWR), which are significant parameters related to solar radiation that affect to the building energy consumptions. Therefore, there is a need to identify how the building energy consumption will be changed by varying these building parameters. In this study, the impact of one measured and three estimated global solar radiation on energy performance of the office building was conducted taking account of SHGC and WWR. As a result, it was identified that the impact of four different solar radiation data on energy performance of the office building was evident regardless SHGC and WWR changes, and concluded that the most suitable solar models was changed from the CRM/ZHM to the MRM as SHGC and WWR increases.

• 한국가구학회지
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• 제25권2호
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• pp.148-153
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• 2014

Importance of energy consumptions has being emphasized because of problems of the energy and environment. So, recently, green wall systems have been installed to reduce building energy consumptions. The green wall systems provide several benefits; they make it possible to maintain moderate thermal comforts by greenery. Greening such a surface wall in the building by plants, the temperature of the wall can be properly controlled that purifies the air and improves the view spanning over the space. This study evaluated the effects of green wall systems on reducing room temperature quantitatively, changing of humidity, decreasing of $CO_2$. Test results were confirmed; first, the space installed by green walls showed that temperature and $CO_2$ decreased and humidity was increased. Second, two structures were compared with the solar radiation, and green wall systems controlled the temperature and humidity stably near the wall regardless of the amount solar radiation. In conclusion, the green wall systems can contribute to thermal comforts and indoor air quality in the buildings.

• KIEAE Journal
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• 제14권2호
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• pp.3-10
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• 2014

Impact by estimation error of hourly horizontal global solar radiation in a weather file on building energy performance was investigated in this study. There are a number of weather parameters in a given weather file, such as dry-bulb, wet-bulb, dew-point temperatures; wind speed and direction; station pressure; and solar radiation. Most of them except for solar radiation can be easily obtained from weather stations located on the sites worldwide. However, most weather stations, also including the ones in South Korea, do not measure solar radiation because the measuring equipment for solar radiation is expensive and difficult to maintain. For this reason, many researchers have studied solar radiation estimation models and suggested to apply them to predict solar radiation for different weather stations in South Korea, where the solar radiation is not measured. However, only a few studies have been conducted to identify the impact caused by estimation errors of various solar radiation models on building energy performance analysis. Therefore, four different weather files using different horizontal global solar radiation data, one using measured global solar radiation, and the other three using estimated global solar radiation models, which are Cloud-cover Radiation Model (CRM), Zhang and Huang Model (ZHM), and Meteorological Radiation Model (MRM) were packed into TRY formatted weather files in this study. These were then used for office building energy simulations to compare their energy consumptions, and the results showed that there were differences in the energy consumptions due to these four different solar radiation data. Additionally, it was found that using hourly solar radiation from the estimation models, which had a similar hourly tendency with the hourly measured solar radiation, was the most important key for precise building energy simulation analysis rather than using the solar models that had the best of the monthly or yearly statistical indices.

• 대한안전경영과학회지
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• 제15권1호
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• pp.161-167
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• 2013

The purpose of this study was to assess power loss in the computer and office automation equipment and identified a way to save power consumptions through field measurement. In this study, the meaning of standby power was to consume power while waiting for the use of any electronic equipment. This standby consumption was about 11% of total power consumption even though we did not seriously realize it. Therefore, it was very important to measure accurate power consumption at the standby status of electronic equipment. In addition, it also helped to reduce potential risks of electricity associated disasters. This study proposed the way to reduce power losses through automatic turn off switches for power outlets and switches. Finally, this study can evaluate power consumption patterns that can reduce power consumptions and potential risks of power related disasters. This also can achieve the goals of sustainability that can reduce environmental impacts by lowering energy consumptions and greenhouse gas emissions.

• 한국신뢰성학회지:신뢰성응용연구
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• 제11권1호
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• pp.83-95
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• 2011

Boiler efficiency has a direct impact on energy consumptions, which results in lower cost of operations and services. Usually high efficiency boilers are regarded as boilers with an efficiency of greater than 90%. However, it is likely that normal boilers are running at significantly lower efficiencies than this. This paper presents a process of developing a highly efficient energy consumption boiler. We adopt direct heat method while normal boilers are designed as indirect heat method. The submerged combustion method is considered to design for very high efficient boiler.

• 대한건축학회논문집:구조계
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• 제36권4호
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• pp.143-152
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• 2020

This study analyzes in detail greenhouse gas emissions in building sector. To this end, this study used data on building characteristics (including building type, region, and construction year) and monthly energy consumptions (including electricity, city gas, and district heat) for all buildings from 2015 to 2018. These data were collected from the National Building Energy Database and the energy consumptions were converted into greenhouse gas (GHG) emissions. The total amount of GHG emissions from the building sector has increased steadily from 2015 (118.1MtCO2eq.) to 2018 (132.6MtCO2eq.). On the other hand, the more recently constructed buildings had lower GHG intensities. This result shows that strengthening building design criteria was effective on the reduction of GHG emissions in buildings, and that the increased buildings contributed to increasing GHG emissions of the building sector. In addition, sales facilities are thought to have the largest reduction potential as they had the highest amount of GHG emissions and GHG intensity. This study is expected to help establish new policies for GHG reduction in building sector as well as to evaluate the effects of existing policies.

• 한국환경과학회지
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• 제15권5호
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• pp.493-501
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• 2006

The increase in environmental loads and energy consumptions has resulted in the need of developed new forms of energy for a sustainable use for the society. Recently, the viability of using unused energy has attracted a great deal of attention. From the view point of using unused energy, the most critical problem can be referred to as the distance between the heat source/sink and heat demand area. The water resource in the city water system was used to solve this distance problem with unused energy. The calculation method of the potential use unit was used to survey the potential of the water resource in the city water system. The amount of theoretical unused energy and energy savings in the model city were estimated using this method. It is estimated that the amounts of energy savings and $CO_2$ reduction correspond to 131.3 GWh and 29280[t-C], respectively, per annual basis.