• 설비공학논문집
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• 제15권6호
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• pp.543-550
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• 2003

In order to saving the energy for HVAC system of buildings, utilization of wind-induced cross ventilation is thought to be promising. However, utilization of natural ventilation alone is not sufficient for maintaining the human thermal-comfort such as in hot and humid regions. A hybrid air conditioning system with a controlled natural ventilation system, or combination of natural ventilation with mechanical air conditioning is thought to overcome the deficiency of wind-driven cross ventilation and to have significant effects on energy reduction. This paper describes a concept of hybrid system and propose a new type of hybrid system using radiational cooling with wind-induced cross ventilation. Moreover, a radiational cooling system is compared with an all-air cooling system. The characteristics of the indoor environment will be examined through CFD (Computational Fluid Dynamics) simulation, which is coupled with a radiation heat transfer simulation and with HVAC control in which the PMV value for the human model in the center of the room is controlled to attain the target value.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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• pp.100-100
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• 2003

An image processing algorithm has been developed in order to analyze the nanofiber web images obtained from a high magnification microscope. It has been known that precise pore detection on thick webs is extremely difficult mainly due to lack of light uniformity, difficulty of fine focusing and translucency of nanofiber web. The pore detection algorithm developed has been found to show excellent performance in characterizing the porous structure, thus being a promising tool for on-line quality control system under mass production. Since the images obtained from an optical microscope represent only web surface, a scale factor has been introduced to estimate the web structure as a whole. Resulting web structures have been compared to those by mercury porosimetry, especially in pore size distribution. It has been shown that those two structures have a strong correlation, indicating that scaling of a single layer web structure can be an effective way of estimating the structure of thick fiber webs.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.239-242
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• 2008

As the distributed generation becomes more reliable and economically feasible, it is expected that a higher application of the distributed generation units would be interconnected to the existing grids. In this context, the Micro Gas Turbines (MGT) by using Bio-gas is being considered as a promising solution. In order to propose a feasible concept of those technologies such as improving environmental effect and economics, we performed a sensitivity study for a biomass fueled MGT using a simulation model. The study consists of 1) the fundamental modeling using manufacturer's technical specifications, 2) the correction with the experimental data, and 3) the prediction of off-design characteristics. The performance analysis model was developed by PEPSE-GT 72, commercial steam/gas turbine simulation technicque.

• 한국정밀공학회지
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• 제24권1호
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• pp.71-78
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• 2007

Abrasive jet machining (AJM) has been traditionally used for removing rusts or paints. Nowadays, this is promising technology for micro bulk machining where brittle substrate materials are used. In order to get accurate details, masks such as metal, polymer or elastomer is inevitable. Among them, photo polymer which is sensitive to the light has been attractive for it's high accuracy using photolithography. In this research, SU-8 as a photo polymer is used since it is adequate for making thick mask. So, this paper describes how to make AJM masks using SU-8 with a photolithography process, and investigates the characteristics of SU-8 masks during AJM process. Also, an example of fabrication using AJM was shown.

• 한국국방경영분석학회지
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• 제15권2호
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• pp.38-55
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• 1989

Reusing software is a promising solution which overcomes the software crisis in the software development environment by improving the software productivity, reliability and maintainability. To develop software, some developers reuse existing softwares, but without an adequate design environment, software reuse would not be applicable. The purpose of this paper is to design and implement the X system, and measure empirically its resuability in the development phases. The development processes of the X system used a software reuse design guidelines within the Object-Oriented Design method and the Ada programming language. In order to measure the resuability, metrics was proposed and applied for each phase of development. The results of this paper address some reusability measurement that may be used as basic data when estimating the amount of reuse for a combined development project of military applications.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
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• pp.471-474
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• 2004

In order to quickly respond to the rapidly changing manufacturing environment, it is imperative for the system to have such capabilities as flexibility, adaptability, reusability, etc. One of the promising approaches for new manufacturing paradigm satisfying those capabilities is the fractal manufacturing system (FrMS). FrMS is based on the concept of autonomously cooperating and self-reconfigurable agents referred to as fractals. In this paper, a fractal template is proposed to have both fractal-specific and agent-specific characteristics and proper techniques for implementation are also selected. The proposed template can be easily extended to the platform of FrMS which supports simulation, shop flow control, and other research issues existed in the manufacturing systems. An example of applying the proposed template to the simulation is also presented.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 전자세라믹스 센서 및 박막재료 반도체재료 일렉트렛트 및 응용기술
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• pp.160-163
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• 2000

Monolayers of lipids on a water surface have attracted much interest as models of biological membranes. but also as precursors of multilayer systems promising many technical applications. They exhibit very interesting physico-chemical properties as two-dimensional and interfacial systems. Until now. many potential methodologies have been developed in order to gain a better understanding of the relationship between the structure and function of the monolayers.

• 융복합기술연구소 논문집
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• 제3권1호
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• pp.9-14
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• 2013

Recently, the development of renewable energy sources in Mongolia has been needed due to climate change and air pollution in Ulaanbaatar as rapid economic growth. Biodiesel can be considered as an alternative fuel for petroleum based diesel in order to decrease air pollution in Ulaanbaatar because of its no emission of particle materials from internal combustion engine in automobile. Rapeseed oil having low cloud point and pour point was suggested as a promising raw material for biodiesel production in Mongolia. Considering high population density and severe air pollution by particle materials and SOx in Ulaanbaatar, prior supplying site of biodiesel in Mongolia was the capital region including Ulaanbaatar. In the production of biodiesel in Mongolia, adsorption process was a effective alternative to washing process for the removal of residual alkali catalyst and reactants due to long winter time in Mongolia. For the stable supply of biodiesel, subsidy and no tax policy is needed in the early stage of biodiesel supply in Mongolia.

• Journal of information and communication convergence engineering
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• 제9권5호
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• pp.551-555
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• 2011

Optical packet switching is a promising technology, which can integrate both data and optical network. In this paper, we present a comparative study of various traffic arrival approaches in WDM packet switches. The comparison is made based on packet loss rate and average delay under uniform and self-similar Pareto traffic. Computer simulations are performed in order to obtain the switch performance metrics. Study shows that burstiness of data traffic has a strong negative impact in the performance of WDM packet switches.

• 경영과학
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• 제20권1호
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• pp.125-139
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• 2003

City gas is becoming an essential resource in households due to its convenience and low price in comparison to other energy sources. However, in order to prepare for the gas market to be saturated, many city gas companies must pursue customer satisfaction management and develop happy call systems for a promising solution. In the development of the happy call systems, the difficult problem is that we cannot contact all customers because of limited resources and calling efficiency in the call center, We should find best customers according to their value. This paper suggests a methodology for the selection of happy call customers when city 9as companies consider two strategies. First, they should launch a new business area. Second, they must attempt to prevent current customers from moving from city gas to other fuels. We will discover important attributes and derive rules of weighting for the attributes through an exploration study that affect customer satisfaction and preference. Through a simulation model, we will show how many customers will be selected by our methodology.