• Journal of Energy Engineering
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• v.13 no.2
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• pp.112-117
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• 2004

Volatile organic compounds (VOCs) are low calorific value gases (LCVG) emitted from chemical processes such as painting booth, dye works and drying processes etc. Characteristics of VOCs are low calorific values less than 150kcal/㎥, high activation energy for ignition and low energy output. These characteristics usually make combustion unstable and its treatment processes needs high-energy consumption. The cyclone combustion system is suitable for LCVG burning because it can recirculate energy through a high swirling flow to supply the activation energy for ignition, increases energy density In make a combustion temperature higher than usual swirl combustor and also increases mixing intensity. This research was conducted to develop optimized cyclone combustion system for thermal oxidation of VOCs. This research was executed to establish the effect of swirl number with respect to the combustion temperature and composition of exhausted gas in the specific combustor design.

• Journal of the Korean Society of Combustion
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• v.11 no.4
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• pp.27-35
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• 2006

The impacts of equivalence ratio on flow structure and flame dynamic in a model gas turbine combustor are investigated using large eddy simulation(LES). Dynamic k-equation model and G-equation flamelet model are employed as LES subgrid model for flow and combustion, respectively. As a result of mean flow field for each equivalence ratio, the increase of equivalence ratio brings about the decrease of swirl intensity through the modification of thermal effect and viscosity, although the same swirl intensity is imposed at inlet. The changes of vortical structure and turbulent intensity etc. near flame surface are occurred consequently. That is, the decrease of equivalence ratio can leads to the increase of heat release fluctuation by the more increased turbulent intensity and fluctuation of recirculation flow. In addition, the effect of inner vortex generated from vortex breakdown on the heat release fluctuation is increased gradually with the decrease of equivalence ratio. Finally, it can be identified that the variations of vortical structure play an important role in combustion instability, even though the small change of equivalence ratio is occurred.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.01a
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• pp.115-118
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• 2015

최근 평균수명이 증가와 더불어 삶의 질이 중요시하고 건강한 삶을 누리고자하는 인류의 염원은 보건의료라는 보편적 가치에 동반 상승할 수 있는 산업과의 결합이 의료관광이라는 새로운 관광시장을 형성하였다. 의료관광은 시장규모가 1억 달러 이상에 이를 것으로 예상되는 고부가가치 산업이다. 또한 외국인을 상대 의료관광은 체류기간이 길고 지출비용도 일반 관광객의 3배 이상으로 지역경제 활성화에 큰 공헌을 하는 대표적인 신 성장 동력산업으로 보고 있다. 더불어 의료관광 추세가 의료서비스를 받으면서 휴양 레저 문화활동을 함께 즐기는 방향으로 발전될 것으로 예측하고 최근 단순 치료 목적이 아닌 방향으로 선회하고 있다. 그러나 국가 정책적 산업으로서 육성에 박차를 가하고는 있으나 의료 기반시설이 열악하고 관련 규정 및 제도적 미비점이 지금의 의료관광 산업에 발맞추지 못하는 실정이다. 이는 주변 경쟁국에 비해 인식부족과 세계시장에 대한 마케팅 활동 부족 및 의료관광 상품의 다양성 부족 등과 함께 의료관광이 활성화하기 위하여 여러 가지 제약이 되는 정책적 문제점들이 있다. 따라서 본 논문에서는 현행 우리나라의 의료관광에 대한 정책적 과제를 살펴보고 이를 개선하기 위한 제도적 개선방안을 모색하고자 한다.

• Journal of computational fluids engineering
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• v.12 no.2
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• pp.37-45
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• 2007

The hybrid Cartesian/immersed boundary method is applied to simulate fluid-structure interaction of a two-dimensional orbiting flexible foil. The elastic deformation of the flexible foil is modelled based on the dynamic equation of a thin-plate. At each time step, the locations and velocities of the Lagrangian control points on the flexible foil are used to reconstruct the boundary conditions for the flow solver based on the hybrid staggered/non-staggered grid. To test the developed code, the flow fields around a flapping elliptical wing are calculated. The time history of the vertical force component and the evolution of the vorticity fields are compared with recent other computations and good agreement is achieved. For the orbiting flexible foil, the vorticity fields are compared with those of the case without the deformation. The combined effects of the angle of attack and the orbit on the deformation are investigated. The grid independency study is carried out for the computed time history of the deformation at the tip.

• The Journal of the Korea Contents Association
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• v.15 no.6
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• pp.81-90
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• 2015

During the last 25 years, independent TV production programing quota policy has been actively evaluated in various aspects except in the field of production personnel. This study focuses on production personnel who has been neglected among the debate of independent TV production programing policy. Especially, this study tries to explore the effect that the policy has brought to production personnel's motivation. After in-depth interviews with 4 professionals and 6 media major senior college students, this study finds that both broadcasting and independent company professionals evaluated the policy performance in negative way. They insist the policy constricts their motivation for production. College students agreed they become unwilling to entering the production filed. The policy should be reconsidered and turn to positive incentives and rewards to motivate production personnel.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.2
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• pp.166-173
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• 2006

This study investigates a heavy duty diesel engine with swept vol. 12.6L, 4cycle-OHC type to verify the effects of the performance and exhaust gas emission according to the variable specifications of both swirl ratio and flow coefficient in inlet port, combustion bowl and fuel injection system. To meet the high BMEP and stringent exhaust emission standard, a turbocharger with wastegate and an intercooler were installed in the engine. Helical port, major design parameters for combustion chamber and electronic fuel injection pump with 1,000bar were reviewed and applied. Confirmation tests were also performed to meet the target value, $NO_x$ 5.0g/kWh and PM 0.1g/kWh of Euro3 exhaust emission legislation. The results of this study show that not only is it effective to use a relatively bigger bowl size for controlling rapid burning condition due to the decreased in-bowl swirl, but also to use a concave cam with double injection rates to decrease $NO_x$.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.2
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• pp.37-46
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• 2007

In this study, combustion fields of the end-burning hybrid combustor with tangential oxidizer injectors are examined. Momentum ratio of oxidizer is used as a main parameter to analyse the combustion efficiency with temperature, pressure, swirl velocity and mixture fraction field. It was found that as momentum ratio decreases the overall combustion efficiency is enhanced with the pressure field being insensitive to momentum ratio keeping quasi-uniform distribution. Irrespective to the momentum ratio, annular hot region commonly occurred in the upper combustion chamber where this phenomenon was left for a future improvement to be followed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.534-546
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• 1990

In this work, an optimum shape synthesis for rolling contact components was done to minimize contact forces considering dynamic characteristics of the system. Even this method was applied to an OHC type cam follower system, it can be expanded to general rolling contact shape design problems which are strictly forced to follow predetermined motion. First, the follower optimum angular motion was derived to minimize the valve peak acceleration while satisfying all the constraints of valve motion. Then the cam and follower contact shape were synthesized to give the proposed follower motion. Theoretically, two components shape to generate a predetermined motion can not be uniquely determined. So the cam shape was syntehsized with parametric synthesis method to minimize the peak contact force between cam and follower when the follower shape is assumed as a circle or an ellipse.

• 한국연소학회:학술대회논문집
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• 1998.10a
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• pp.79-84
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• 1998

In this paper we show design and operation of 1MWth pulverized coal combustion test facility. The test facility is consists of coal feeding system, furnace and flue gas treatment system. The furnace is equipped with a top-fired burner in order to avoid influence of gravity on the coal particles. There are two part of vertical(VP) and horizontal pass(HP) at furnace. We can measure temperature and species of coal flames in vertical pass. Also, there is horizontally arranged section where investigation regarding corrosion and deposit formation will be carried out. The burner of combustor was externally air staging burner(EASB) type made by IFRF. The pulverized high bituminous(Blair athol) coal from Australia was used as fuel, and the particle size less than 80 ${\mu}m$ was 83.4%. Overall excess air ratio was 1.2.

• Proceedings of the Korean Society of Computer Information Conference
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• 2012.07a
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• pp.179-182
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• 2012

21세기 지식정보화 사회는 데이터를 수집, 조작, 가공할 수 있는 능력이 중요한 사회이다. 외국의 경우, 이러한 사회적 흐름에 걸맞게 초등학교 교육과정에서부터 체계적인 데이터베이스 교육이 실시되고 있으나, 우리나라는 아직 단순한 정보의 검색 및 활용 교육에 그치고 있다. 심지어 초등 정보영재를 위한 데이터베이스 교육 역시 컴퓨터 과학의 타 영역에 비해 매우 소홀히 다루어지고 있는 실정이다. 이에 본 연구에서는 국내외 데이터베이스 교육 현황을 분석하고, 초등학생을 위한 데이터베이스 교육 방안을 교육 내용 및 수준, 교수 학습 방법 및 평가의 측면에서 제안하였다. 내용 및 수준의 경우 초등학생이 실생활에서 접할 수 있는 과제를 중심으로 데이터베이스의 개념, 조작, 응용하기를 통해 문제를 해결할 수 있도록 하고, 평가하기는 과제 해결을 위해 필요한 지식 및 기술 수준 뿐만 아니라 문제해결력, 협력적 태도의 종합적 평가 방안을 제안하였다.