• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.40-43
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• 2006

Public demand for the heat pump system as a next generation energy equipment is increasing for its eco-friendly and cost-effective advantage. Many researches have been concentrated on how to calculate and develop its own efficiency, while the possible effect of the heat pump operation on the whole subsurface temperature distribution is relatively less considered, During the current study, subsurface temperature disturbance caused by seasonal surface temperature cycle in Busan area and general W-tube heat pump operation is simulated in 3-dimensional heterogeneous medium. It shows that subsurface deeper than 10m from the surface remains nearly unchanged throughout the 4 seasons and groundwater convect ion in highly permeable layer near the surface acts like a main path of heat plume from heat pump system, This implies the significance of detail descript ion in shallow sedimentary layer or highly permeable layer which plays an important role on the regional flow advection and heat transfer. Also, the effect of groundwater convection increases when the arrangement of the 2 injection pipes and 2 extract ion well is maintained parallel to groundwater flow. Therefore, more careful and detail investigation is required before installation and operation of heat pump system that it may not cause any possible change of microbial ecosystem in the shallow subsurface environment or 'contamination of temperature' for groundwater use as well as the loss of efficiency of the equipment itself. This can also help to design the optimized grouting system for heat pump.

• 대한기계학회논문집B
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• 제25권6호
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• pp.799-803
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• 2001

Miniature heat pipe(MHP) with woven-wired wick was used to cool the CPU of a notebook PC. The pipe with circular cross-section was pressed and bent for packaging the MHP into a notebook PC with very limited compact packaging space. A cross-sectional area of the pipe is reduced about 30% as the MHP with 4mm diameter is pressed to 2mm thickness. In the present study a performance test has been performed in order to review varying of operating performance according to pressed thickness variation and heat dissipation capacity of MHP cooling module that is packaged on a notebook PC. New wick type was considered for overcoming low heat transfer limit when MHP is pressed to thin-plate. The limiting thickness or pressing is shown to be within the range of 2mm∼2.5mm through the performance test with varying the pressing thickness. When the wall thickness of 0.4mm is reduced to 0.25mm for minimizing conductive thermal resistance through the wall of heat pipe, heat transfer limit and thermal resistance of MHP were improved about 10%. In the meantime, it is shown that the thermal resistance and heat transfer limit for the MHP with central wick type are higher than those of MHP with existing wick types. The results of performance test for MHP cooling modules with woven-wired wick to cool a notebook PC shows the stability as cooling system since T(sub)j(Temperature of Processor Junction) satisfy a demand condition of 0∼100$\^{C}$ under 11.5W of CPU heat.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.144-144
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• 2010

Reasonable usage methods of energy resources, which are limited for human beings to use, consists of new & renewable energy (NRE) and demand side management (DSM). All technologies and policies for energy resources are classified into two fields, methods for using new energy resources and methods for using conventional fuel energy resources. Various development activities for these fileds have been implemented and various subsidy programs have been operated to penetrate into markets rapidly. These subsidy programs have various types of subsidy by energy resources and programs and the budget are funded by government, which is called Electric Power Industry Basis Fund and is managed considering technology level, economic analysis, global environment, etc. These subsidy programs are managed by Korea Energy Management Corporation (KEMCO) for NRE and by Korea Electric Power Corporation (KEPCO) for DSM, the management are different among two corporations because the purposes and features of establishment are different though these are all public organization. KEMCO is managing the NRE subsidy programs according to the government will, while the management of KEPCO subjects to power system operations though the government will for DSM is considered. NRE which is on the initial phase of diffusion would not affect on power system seriously but the affects could be grown when the diffusion and importance are expanded. Hence some integrated affection analyses considering NRE and DSM are required and this paper shows the concept of integrated operation strategies with ground source heat pump systems which are related with two fields simultaneously.

• 한국식품조리과학회지
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• 제29권3호
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• pp.257-265
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• 2013

The purpose of this study was to understand the characteristics of senior consumers' food-related lifestyle and to investigate their demand for menu development of senior' friendly food products. An one-to-one survey method was used for data collection, and the survey was conducted with 490 senior participants who are over 55 years-old living in Seoul and Kyunggi area. The main results of this study were as follows: Most participants usually spend from 60,000 to 150,000won on food a month, and the female participants played a decisive role on food purchasing and preparation. They preferred home meal for their three regular meals to bread, convenience food, or eating-out. For menu development of senior-friendly food products, the demand for food products using moist-heat cooking method was higher than those using dry-heat cooking method. Also, the respondents did not like strong taste such as salty, spicy, or bitterness in senior-friendly foods, and wanted to have a variety of noodle, kimchi, meat, seafood meals.

• Design & Manufacturing
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• 제12권2호
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• pp.16-21
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• 2018

Recently, as the demand for high-precision parts increases due to industrial development, a machine tool system for ultra-precision machining and polishing has been actively developed. As a result, there is an increasing demand for ultra-precision surface roughness along with dimensional processing. However, due to the increase in processing time due to the demand for ultra-precise surfaces and enormous facility investment, it is difficult to secure competitiveness. The polishing process using the abrasive film in super precision machining has been applied to machines, electronic devices, aerospace, and medical fields. Super finishing using the abrasive film which is applied in the industrial field recently can achieve high surface roughness in a short time. Super finishing using the abrasive film which is applied in the industrial field recently can achieve high surface roughness in a short time. Also, application of industrial field is increasing due to advantages such as low noise and low dust. Recently, researches on stainless steel having strong resistance to corrosion, heat resistance, heat resistance, toughness and weldability have been actively conducted with respect to the nuclear energy industry or marine development. Therefore, in this study, surface roughness and residual stress were measured after SUS304 polishing using dynamic analysis of film polishing apparatus and polishing film.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.184-189
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• 2009

In order to improve the operation of energy systems, it is necessary for the urban communities to have reliable optimization routines, both computerized and manual, implemented in their organizations. However, before a production plan for the energy system units can be constructed, a prediction of the energy systems first needs to be determined. So, several methodologies have been proposed for energy demand prediction, but due to uncertainties in urban community, many of them will fail in practice. The main topic of this paper has been the development of a method for energy demand prediction at urban community. Energy demand prediction is important input parameters to plan for the energy planing. This paper presents a energy demand prediction method which estimates heat and electricity for various building categories. The method has been based on artificial neural networks(ANN). The advantage of ANN with respect to the other method is their ability of modeling a multivariable problem given by the complex relationships between the variables. Also, the ANN can extract the relationships among these variables by means of learning with training data. In this paper, the ANN have been applied in oder to correlate weather conditions, calendar data, schedules, etc. Space heating, cooling, hot water and HVAC electricity can be predicted using this method. This method can produce 10% of errors hourly load profile from individual building to urban community.

• 한국자원식물학회지
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• 제13권3호
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• pp.208-212
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• 2000

보온 피복재 종류가 자옥 포도 유목의 월동시 동해방지, 노동력 절감 및 병해 발생 억제에 미치는 영향을 구명하기 위하여 11월 하순에 짚을 덮은 다음 보온덮개B, 킬딩, 칼라부직A 및 백색니들펀칭부직포 등을 피복하여 시험한 결과를 요약하면 다음과 같다. 1. 보온력은 백색니들펀칭부직포가 가장 불량하였고, 다른 보온재간에는 차이가 미미하였다. 2. 발아는 보온덮개B에서 빨리 시작되었으며, 발아 9일 후에도 발아율이 79.7%로 타 보온재 보다 2.3∼12.5% 높았다. 3. 생육은 보온재간에 차이가 없었으며, 병해 발생은 킬딩과 보온덮개B에서 뿌리혹병이 지수 3.0∼3.2로 다소 많이 발생되었을 뿐 기타 병해는 처리간에 차이가 없거나 미미 하였다. 4. 작업 단계별 소요노력은 보온덮개B에 비하여 킬딩은 6% 많았으나, 칼라부직A는 6%, 백색니들펀칭 부직포는 15%적었다.

• 한국농촌건축학회논문집
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• 제19권2호
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• pp.9-16
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• 2017

The study analyzed the heat losses and the building energy efficiency grade by the energy simulation using the ENERGY# and ECO2 programs for the three types of Standard design of rural houses. It was calculated the energy efficiency rating by the ECO2 program for the rural housing standard design, and the energy demand and the energy consumption by each factor were compared and analyzed. And it analyzed energy consumption by element of each house by ENERGY # program. As a result, first in the evaluation of the energy efficiency grade of buildings by the ECO2 program, the rating for primary energy requirement for the housing newly built by the standard design of rural house is expected to range from 2 to 4 with 189.3 to $238.7kWh/m^2.a$. Second, the energy loss of each part of standard design of rural housing occurs in the order of ventilation 39%, window 33%, outer wall 14%, roof 9%, bottom 5%, and energy loss through ventilation and window occurs more than 70%. Third, the most beneficial effects on the energy efficiency grade is obtained the lowest grade of all three types by 2 when the lowering of the window and door heat transmission rate and the lowering of the light density, and the heat exchange ventilation device is not installed. Fourth, in the standard design of rural housing, the energy demand is occupied by heating > hot water > lighting order, and the order of the weight is changed in order of heating > lighting > ventilation > hot water. Fifth, building energy efficiency assessment system needs to establish policy for fixing rural housing energy as a practical device to ensure energy performance and quality.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2009년 춘계학술발표대회 논문집
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• pp.175-180
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• 2009

According to an increasing demand of political support and development on renewable energy as a solution for the energy problem in Korea, the government has established a goal to raise renewable energy supply from 2.27% to 5% until 2011. Especially in the case of public building in which energy use is in great demand, it would bring a great advantage to develop and utilize the Photovoltaic System as an electric energy and Geothermal Heat Pump System as a thermal energy. On the occasion of Photovoltaic System, Photovoltaic module can be used as an architectural material so that it can reduce construction cost and when we use solar energy, it is possible to make building's own power supply. As for Geothermal Heat Pump System, It can be used infinitely as long as the solar energy exist and operation cost is cheap and yearly efficiency is stable. However, we need to make a plan to reduce early investment expanses for these two renewable energy systems and to expand a diffusion rate as we develop a competitive domestic technology level. So in this study, we are going to perform evaluation of economical efficiency according to the introduction of Photovoltaic System and Geothermal Heat Pump System in public buildings which will be built up inside of Daegu Sin-seo innovation city. As a first step, we will investigate present installation condition of these two renewable energy systems and based upon that, will seek efficient introduction program of renewal energy systems that can be applied in public buildings.

• 한국컴퓨터정보학회논문지
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• 제20권4호
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• pp.11-16
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• 2015

데이터센터는 전 세계적으로 클라우드 기반 IT 솔루션의 발전과 더불어 빅 데이터, 교육, 커뮤니케이션 수단의 발달과 전자기기 사용이 증가함에 따라 국내외로 그 수요가 꾸준히 증가하는 추세에 있다. 이러한 데이터센터의 증가는 IT장비의 발전을 가속화 시켰으며 서버 랙의 발열 또한 크게 높이는 결과를 가지고 왔다. 데이터 센터의 전산 발열량은 IT서버 전력사용의 99%이상이 열로 변환되므로, 서버의 크기와 용량이 증가할수록 발열량 또한 상승하게 된다. 본 논문에서는 공냉식 냉각방식을 중심으로, 데이터센터의 에너지 절감을 위한 공조시스템을 연구 하였으며, 해당 시스템의 성능분석 및 모의실험을 통하여 실제로 에너지 절감 효과가 있는 것으로 분석되었다.