• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.679-681
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• 2014

에너지저장시스템(Energy Stroage System, ESS)은 잉여 전력과 에너지를 필요한 시점에 적절하게 공급할 수 있도록 에너지를 저장해두는 기술로 전기에너지의 픔질 및 효율성을 극대할 수 있는 에너지 활용 시스템이다. 미국을 비롯한 유럽 선진국들은 다양한 ESS 관련 제도정비 및 개선을 통해 ESS 산업의 활성화를 유도하고 있다. 우리나라의 경우, 신재생에너지 확대 정책을 수립하고 에너지 저장기술을 그린에너지 분야의 주요 핵심과제 선정하여 체계적인 육성전략을 추진 중에 있다. 그러나, ESS 도입 및 활성화를 위한 법제도적 기반이 마련되어 있지 않고, ESS도입에 대한 경제적 효과성에 대한 객관적인 기준이 없어, ESS의 보급 및 활성화가 제대로 이루어지지 않고 있는 실정이다. 본 연구에서는, ESS의 보급과 활성화를 위해 효과적으로 ESS의 경제성 분석하기 위한 기법을 제시하는 것을 목적으로 한다. 세부적으로는 전기요금 산정방식에 따라 ESS의 운영모형을 정의하고, 운영모형별 경제성을 분석하기 위한 기법을 제시한다. 그리고, 실제 데이터를 활용하여 ESS로 절감할 수 있는 피크 크기를 구할 수 있는 알고리즘을 구현한다. 또한, 저감 피크와 온도, 습도에 대한 회귀 분석을 통하여 최대저감피크를 예측할 수 있는 해법을 제시한다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.2
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• pp.169-177
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• 2024

In this paper, the effect on cement clinker and cement quality was studied to prove the effect of reducing the sintering temperature of cement clinker as a mineralizer to recycle fluorine based semiconductor sludge, an industrial by-product. In addition, a verification study was conducted to compare the properties of clinker and cement at different temperatures when natural fluorite, previously used as a mineralizer, was used. As a result of the study, semiconductor sludge showed sufficient effectiveness as a mineralizer and could replace natural fluorite, an existing mineralizer.

• Fire Science and Engineering
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• v.23 no.3
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• pp.103-109
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• 2009

The thermal degradation of concrete results mainly from two mechanisms. The first one is related to phase transformations of constituents at different temperatures. The initial constituents transform to other phases due to elevated temperature. The second mechanism is related to the temperature sensitivity of the mechanical properties of the constituents in concrete. Therefore, the degradation of concrete under high temperatures must be studied from both mechanical and chemical points of view. This study was performed as a basic study to propose the material models of concrete exposed to high temperatures considering above two mechanisms. This study presents a prediction model on the porosity of hardened cement paste considering phase changes according to temperature increase.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.5
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• pp.675-681
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• 2014

This study was conducted to determine the optimal roasting temperature (90, 100, 110, and 120; fixed time of 20 minutes) of small black coffee beans under various roasting conditions. The roasting temperature range and fixed time were the same as our preceding study. After roasting, the general composition, isoflavone contents, and antioxidant activities were measured. As the results of the proximate composition analysis of small black beans according to roasting conditions, only moisture decreased among them, whereas other general compositions were not affected. The DPPH and ABTS radical scavenging activities were the highest at a roasting temperature of $120^{\circ}C$. Total polyphenol and total flavonoid contents were also highest at $120^{\circ}C$. Isoflavone contents showed a positive correlation with DPPH and ABTS radical scavenging activities, as well as total phenol and flavonoid contents. These results suggest that the optimal roasting conditions of small black beans were determined to be $120^{\circ}C$ for 20 minutes.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.3
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• pp.46-53
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• 2009

Urbanization brings several changes to the natural environment. Its consequences can have a direct effect on climatic features, as in the Urban Heat Island Effect. One factor that directly affects the urban climate is the green area. In urban areas, vegetation is suppressed in order to accommodate manmade buildings and streets. In this paper we analyze the effect of green areas on the urban temperature in Seoul. The period selected for analysis was July 30th, 2007. The ground temperature was measured using Landsat TM satellite imagery. Land cover was calculated in terms of city area, water, bare soil, wet lands, grass lands, forest, and farmland. We extracted the surface temperature using the Linear Regression Model. Then, we did a regression analysis between air temperature at the Automatic Weather Station and surface temperature. Finally, we calculated the temperature decrease area and the population benefits from the green areas. Consequently, we determined that a green area with a radius of 500m will have a temperature reduction area of $67.33km^2$, in terms of urban area. This is 11.12% of Seoul's metropolitan area and 18.09% of the Seoul urban area. We can assume that about 1,892,000 people would be affected by this green area's temperature reduction. Also, we randomly chose 50 places to analysis a cross section of temperature reduction area. Temperature differences between the boundaries of green and urban areas are an average of $0.78^{\circ}C$. The highest temperature difference is $1.7^{\circ}C$, and the lowest temperature difference is $0.3^{\circ}C$. This study has demonstrated that we can understand how green areas truly affect air temperature.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.15-22
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• 2014

Multiple devices have been installed to reduce exhaust emissions and to increase thermal efficiency. Those devices reduce the exhaust pipe opening area and increase the exhaust gas pressure. The pressure increase disturbs a gas flow and has a bad effect on the engine performance. However there is some study that NOx can be reduced with exhaust gas pressure increase. In this study an engine performance is tested with various opening ratios. The result shows that the fuel consumption rate is reduced in case of little amount of the pressure increase, and NOx is reduced with the pressure increase, while the concentration of the toxic exhaust gases are increased in the case of high back-pressure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.416-424
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• 2019

In Korea, press concrete in basements is mainly applied using plain concrete. This system has undesirable defects such as cracks caused by plastic shrinkage and irregular temperature distribution. To solve this problem, metal lath and fibers have been used in the past. However, they have not been effective in controlling cracks. This study analyzed the reduction of plastic shrinkage cracking for press concrete using various admixtures in a basement has been. In the air contents test, the specimens with various admixtures showed air contents similar to plain concrete (4.5±1.5%). The specimens using silica fume, super plasticizer agent, and SBR showed higher compressive strength by about 10-15% than plain concrete. Cracking decreased when the MC, super plasticizer, and SBR were added. When MC was used in the concrete, the plastic shrinkage did not occur.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.288-295
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• 2011

The objective of this study is to develop a proper absorbent-pervious pavement. By using single graded aggregates and SAP, permeability and water absorbability of absorbent-pervious pavement are improved, and also temperature reducing effect is found out. And several tests such as compressive and flexural strength tests, and permeability/water absorption tests of absorbent-pervious pavement are carried out to verify these kind of effects. The compressive and flexural strengths are increased according to decrease of single graded aggregate size, and increase of SAP content. And the volume of water retention and absorbability are increased according to the increase of SAP content and these are also increased in small size of single graded aggregate. And about $20^{\circ}C$ of difference is observed in surface temperature between normal asphalt pavement and absorbent-pervious pavement.

• Journal of the Korea Concrete Institute
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• v.20 no.5
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• pp.661-668
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• 2008

It is necessary to develop a new technology for effectively reducing hydration heat and controlling thermal cracking caused increasing construction of large size massive concrete structures such as mat foundation of high-rise building, grandiose bridge, and LNG tank. Therefor, to develop a new technology for reducing hydration heat of large size massive concrete in this study, after developing the latent heat binder for controling hydration heat of concrete by application of latent heat material, it was investigated basic properties and durability such as slump, air content and compressive strength, shrinkage properties, permeability, freezing and thawing resistance, corrosion, and hydration heat generation properties of concrete using latent heat binder. As a test result, it was confirmed that latent heat binder was not affected adversely the basic property and durability of concrete, and was advanced on the reduction of hydration heat and control of thermal crack. It is expected to be applied as the excellent technology on the management of hydration heat and thermal crack in large size mass concrete structures.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.12
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• pp.2255-2261
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• 2000

To eliminate $NO_x$ in diesel emission. selective catalyst reduction (SCR) was used in real diesel engine. Among the SCR methods, metal oxide and perovskite catalysts were introduced in this paper. The removal efficiencies with various major, promoter catalysts on ${\gamma}-Al_2O_3$ at different reaction temperature were investigated, and $LaCuMnO_x$ catalyst which has high removal efficiency at the temperature of real diesel exhaust gas was selected. $NO_x$ reduction was carried out over these catalysts in the flow-through type reactor using by-pass ($SV=3,300h^{-1}$). Under the given condition to this study, perovskite catalysts showed considerably high removal efficiency and $LaCuMnO_x$ was the best one among these catalysts in the temperature range of $150{\sim}450^{\circ}C$.