• Fire Science and Engineering
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• v.29 no.6
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• pp.40-44
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• 2015

National and international standards for curtain wall glass are focused on wind pressure and insulation performance, but disasters such as fires and earthquakes are not considered. Failure of curtain wall glass during a fire in a skyscraper increases the loss of lives and property due to the spread of fire. Therefore, the fire resistance of curtain wall glass should be investigated, and technology to prevent glass failure should be developed to prevent fire damage due to spreading fire. It is important to predict the starting point of cracks and the cause of glass failure to prevent it effectively using the limited water in a skyscraper. In this study, double glazed glass was exposed to a radiator in an experiment performed to analyze the thermal characteristics. The results show that glass that was not directly exposed to high temperature and pressure was broken. To identify this failure case, numerical analysis was performed. Three glass specimens were installed in an ISO 9705 room and exposed to radiation using a radiator, and a thermocouple was used to measure the temperature on the surface of the glass. Widely used double glazed glass was analyzed for weakness to fire.

• Fire Science and Engineering
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• v.25 no.6
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• pp.168-177
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• 2011

The combustion test for real box of AC outdoor unit has been performed in this study in order to estimate the fire hazard in multi-system type of AC outdoor unit which is currently used for commercial use. The result showed that in test, there was explosion inside of AC outdoor unit, and flame erupted and fire spread through upper side grill. And then this fire burnt the combustibles such as wires, electronic control board, heat exchange copper plate and plastics etc inside the unit, refrigerant gas pipe was burst due to fire, and accelerated the explosion and flame eruption to outside while the refrigerant was erupting. It is found in this test that the maximum heat release rate of AC outdoor unit is 5,830 kW, the maximum internal temperature measured with infrared camera and thermocouple is $1,201^{\circ}C$, maximum ambient temperature is $881^{\circ}C$, and flame rose higher than about 5 m. It is concluded that the fire in AC outdoor unit cause fire to combustibles around the unit, and may give big damage by generating the secondary fire. It is expected that the result obtained from the test on the real object may be applied to fire realization of AC outdoor unit and estimation of fire spreading to the combustibles around in the future computer simulation.

• Journal of Digital Contents Society
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• v.18 no.6
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• pp.1057-1065
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• 2017

Coding education for elementary school student spreads around the world. Game activity that children like is one of coding education methods. Among these, a board game is a tool where 3~4 children can participate together. This study developed a storytelling-based board game to help elementary school students understand Software education. The board game is composed of board, three types of command cards and dice. This study simultaneously surveyed and interviewed 57 fifth- and sixth-grade students at elementary school after playing the board game 4 times so as to analyze the usefulness of the developed software board game. In the results of study, most of elementary school students would be interested and participated in active. Elementary school students actually got to know algorithm easily through board game activity, and learned basic programming concepts such as sequence, condition, loop, variable and operation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.10
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• pp.966-978
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• 2011

Transpiration cooling is the most effective cooling technique for the high-performance liquid rockets and air-breathing engines operating in aggressive environments with higher pressures and temperatures. When applying transpiration cooling, combustor liners and turbine blades/vanes are cooled by the coolant(air or fuel) passing through their porous walls and also the exit coolant acting as an insulating film. Practical implementation of the cooling technique has been hampered by the limitations of available porous materials. But advances in metal-joining techniques have led to the development of multi-laminate porous structures such as Lamilloy$^{(R)}$ fabricated from several diffusion-bonded, etched metal thin sheets. And also with the availability of lightweight, ceramic matrix composites(CMC), transpiration cooling now seems to be a promising technique for high-performance engine cooling. This paper reviews recent research activities of transpiration cooling and its applications to gas turbines, liquid rockets, and the engines for hypersonic vehicles.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.620-624
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• 2009

한국농어촌공사에서 2008년도 환경부 하수처리장 재이용사업으로 선정된 제주특별자치도 서부(판포)하수처리장 농업용수재이용 사업을 위탁받아 사업을 진행하고 있다. 하수처리수를 농업용목적으로 재이용하기 위해서는 농업용수 재이용수질기준에 우선 적합해야하고 작물재배실험 및 수질, 토양, 생태환경 영향 뿐만아니라 공중보건위생 위험도 등 종합적이고 체계적인 연구결과를 바탕으로 적용해야한다. 이를 위해 수자원 프런티어사업단의 "농업용수재이용시스템적용 연구"에서는 하수처리수의 농업용수 재이용과 관련한 종합적인 연구를 통해 농업환경피해를 최소화하고 안전성 확보를 위한 방안을 수립하고 있다. 서부하수처리장은 제주도 한경면 판포리에 위치하여 2007년도에 준공하였고 2008년도부터 본격적으로 가동중이다. 재이용 공급대상 농경지는 처리장의 주변 농경지로 249ha를 대상으로 하고 있으며 사업시행을 위해 타당성 분석, 기본계획 및 실시설계를 시행하였고 2009년 12월까지 시설의 설치 및 시험가동 완료를 목표로 하고 있다. 본 연구에서는 농업용수 재이용사업의 계획 수립을 위해 필요한 분석활동 내용과 안전하게 제주도 하수처리수를 재이용할 수 있는 농업용수 재이용시스템 설계내용을 중심으로 기술하였다. 현재 농촌은 도시화가 전국으로 확산되면서 농촌의 쾌적성은 점차 훼손되었고 하천 호소의 수질이 더욱 악화되고 있다. 또한 농촌지역의 도시화에 따라 하수처리장의 농촌지역에도 늘어가고 있으며 이제는 농촌지역과 도시지역이 구분되지 않고 혼합되어 있는 형태로 발전하고 있기 때문에 과거의 농업활동도 변화되고 있으며, 하천에서 취수하는 용수중에서 농업용수로의 사용이 부적합한 용수가 취수되고 있다. 따라서 하수처리수의 농업용수 재이용시스템과 같이 수처리를 이용한 농업용수의 공급방안이 확대될 것으로 판단된다.

• Journal of Intelligence and Information Systems
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• v.7 no.1
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• pp.1-15
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• 2001

Recently, Internet based Electronic Commerce is recognized as one of the alternatives for strengthening sales power of small and medium companies. However, small and medium manufacturers can't adjust properly to the new environment because they are in short of money, personnel, and technology. To cope with this problem, this paper deals with the development of virtual manufacturing agent to support sales agent. The sales activity of most of parts manufacturing companies is based on orders of buyers. The process of promotion, receipt and selection of orders of the parts manufacturing is closely coupled with the load status of the production lines. On deciding whether to accept an order or not, as well as negotiating with buyers, sales person needs information such as load and schedule of production lines, manufacturability of the order. Therefore, the functions of virtual manufacturing agents manufacturability analysis, process planning, and scheduling are key features in developing an agent of sales activity for the parts manufacturing business. While most of research on virtual manufacturing system so far is focused on the simulation of each product, this paper deals with the development of agent assisting internet-based product sales by supporting production information promptly. The pilot system of virtual manufacturing agent is implemented using KQML-based agent template and Java-based expert system shell for a small molding company.

• International Commerce and Information Review
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• v.3 no.2
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• pp.93-111
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• 2001

The purpose of this paper is to study the mechanism of Acquisition of Customer Knowledge through Web Site at Global Electronic Commerce Times in Korea. The major findings of this paper is that the models of inter-business alliance network for EC based on contents, types of participating company, categories of business of participating company, modes of alliances, and concentrated industry or function are various and complex. Therefore all companies should know this result and reflect in their business strategy.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.2
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• pp.432-445
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• 1994

From a theoretical analysis point of view, the 2-stage precipitator is decomposed into two units: charging cell and collecting cell. Collection efficiency predictions of the two-stage parallel-plate electrostatic precipitator have been performed theoretically incorporating with the charging and the collecting cells. Particle trajectorise passing the charging cell have been modeled as a simple one. Particle charge distribution at the outlet of the charging cell is calculated through integration of the present unipolar combined charging rate along the entire particle trajectory, and average charge of particles at the outlet of the charging cell is obtained from the particle charge distribution. As for the collecting cell, the diminution of particle concentration along the longitudinal direction of the collecting cell is investigated considering the conventional Deutsch's theory and the laminar theory. One should note that the collection efficiency formula derived is based on monodisperse aerosols. It has been confirmed through the analysis that predictions of particle charge by applying White's unipolar diffusion charging theory overpredict actual cases in the continuum regime, while predictions by Fuch's unipolar diffusion charging theory indicate the reasonable result in the same regime. Theoretical predictions of collection efficiency are also compared with the available experimental results. Comparisons show that the experimental results are consistently located in the collection efficiency region bounded by the two limits, the Deutsch and the laminar collection efficiencies. Finally design parameters of the 2-stage electrostatic precipitator have been investigated systematically through the one-variable-at-a-time method in terms of collection efficiency. Applied voltages on the corona wire of the charging cell and the plate of the collecting cell, and the average air velocity have been selected as the design parameters.

• Science of Emotion and Sensibility
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• v.5 no.4
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• pp.45-49
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• 2002

Recently, virtual environment systems are used in various application fields such as industry, medicine, and training and education. However, the negative effect, cybersickness including nausea, visual fatigue, and disorientation, could be happened while using VR systems. It prevents VR system from spreading much more. To control the cybersickness, first of all, the objective measurement method should be established. As one of alternative methods, the postural instability could be a measure of cybersickness. In this study, 45 participants' postural sway before and after experiencing a H driving simulator was measured by using a force platform. Especially, we examined if two factors, motion and feedback, could affect on the postural instability The results showed the postural instability slightly increased after experiencing the VR driving simulator. For the factors, the providing of motion synchronized to visual display showed statistical significant decrease in postural sway along lateral side. To check the effectiveness of postural instability as a cybersickness measure, further studies are needed.

• Polymer(Korea)
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• v.25 no.2
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• pp.151-160
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• 2001

Polymeric membranes consisting of poly(d,1-lactide) as a polymer matrix and crystallizable progesterone as a drug were prepared by coagulating polymeric solutions. The homogeneous casting solutions in dimethyformamide were solidified by using three different coagulating processes : solvent evaporation under vacuum, solvent extraction via immersion into the nonsolvent bath, or vapor exposure at high humidity condition. With solvent removal via evaporation under vacuum, the cast solution film was vitrified to form a homogeneous film containing progesterone of spherical shape distributed evenly in the film. Being prepared by solvent extraction via immersion into a water bath, the resulting membrane showed an asymmetric structure, with progesterone of big crystallites distributed unevenly in the structure. On the other hand, the coagulation under high humidity transformed the cast film into a sponge-like structure, where progesterone took a shape like flake.