• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.8
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• pp.92-98
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• 2005

Screen can provide any disturbed resistance that affects the change in characteristics of turbulence, velocity and pressure distributions of the flow field, and thus it has been widely used to control the flow. Some previous related studies for compressible flows have limitations such as, considering relatively low-Mach-number flows in the range of 0.3 ∼ 0.7, and not observing the detailed shock structures of the flow fields. An experimental study on highly compressible axi-symmetric supersonic jet flow fields behind wire-gauze screen has thus been carried out. Continuous/instantaneous flow images by Schlieren flow- visualization technique and the information of Pitot pressure/flow-noise measurements of the flow field behind the screen for various jet expansion conditions have been obtained. Effects of various porosity and inclination angles of the screen at the nozzle exit have also been investigated, and the experimental results have been compared to the case with no screen installed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.3
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• pp.590-598
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• 1988

Viscous flows through a screen normal to an uniform flow are numerically simulated. A .kappa.-.epsilon. model is adopted for evaluation of the Reynolds stresses. The existence of a screen is regarded as extra sources in the momentum equations. The amount of extra sources is related to the resistance coefficient and the refraction coefficient of the screen. Flows are numerically simulated for various resistance coefficients and heights of the screen and Reynolds numbers. The present method has been verified to reasonably simulate viscous wakes and shear layers of the screen, for which the inviscid theory is quite limitted. As the fluids approach the screen, the velocity is reduced and the pressure is raised to satisfy the Bernoulli equation. After passing the screen, the velocity shows its minimum value at the down-stream, but static pressure is slowly recovered. A detached separation-bubble from the screen appears as the resistance coefficient is increased to a certain level. Such results are qualitatively in agreement with limitted experimental data available. The turbulent kinetic energy shows its maximum value at further down stream and decrease thereafter.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.274-284
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• 1991

Mean flows and Reynolds stresses through circular and elliptic wire-mesh screens in the wind tunnel are measured by using the hot-wire system, and flow structures are investigated. Flow in the core of the wake are nearly uniform and the shear layer is developed along the edge of the screen The turbulent kinetic energy in the core decreases at the fast rate. However turbulence components are not in local equilibrium in the shear layer. The shear layer of the circular screen develops outward according to the radial mean motion. On the other hand, 3-dimensional transverse mean motion was turned to the main mechanism for the elliptic shape of the wake to be circular at the downstream.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1337-1345
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• 2007

The present study is a basic investigation for systematically proceeding disaster prevention studying the effect of platform screen door in case of fire at the subway station. In the paper, the characteristics of screen door were surveyed and described. The fully closed platform screen door and the island type of subway station were employed for simulation-study. Numerical simulations of fire driven flow at the subway station with platform screen door were performed with commercial fire CFD code. For analyzing of the effect of platform screen door, the fire simulations with and without the platform screen door were compared. For the fire location, the one is located on the platform and the other case on the railway. The Ultrafast model was taken as fire growth scenario. The maximum heat release rate was 10MW. The propagated time of the heat and smoke to stairs was within 4 minute when the fire is located on the platform. However the heat and smoke propagation was block off by screen door when the fire is located on the railway.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.226-232
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• 2007

모바일폰의 LCD 전면화 추세로 인해 터치스크린을 기반으로 하는 모바일폰이 컨셉폰의 형태로 선보여지고 있고, 부분적으로 터치스크린을 차용한 모바일폰이 국내, 국외에 출시되고 있다. 터치스크린은 간편하고 직관적인 조작감을 제공하며 유동적인 인터페이스를 가능하게 하는 장점이 있다. 그리고 이러한 터치스크린의 장점을 적극적으로 활용할 수 있도록 하는 진보된 인터랙션 스타일도 다양하게 제안되고 있다. 하지만 기존의 터치스크린 기반의 모바일폰은 스타일러스를 그대로 사용하듯, 제한적이고 전형적인 인터렉션만을 제공하고 있고, 제안된 진보된 인터렉션 스타일들도 터치스크린 기반의 모바일폰에 직접적으로 활용하기는 어려운 실정이다. 본 연구는 진보된 인터랙션 스타일 중에서, 원 포인팅과 2개 이상의 포인팅이 가능한 멀티 포인팅 인터랙션을 연구하여 터치스크린기반의 Full LCD 모바일폰에 적합한 인터랙션 스타일을 제안한다. 이를 위해, 인터랙션에 대한 문헌연구와 함께 터치스크린을 기반으로 하는 다양한 디지털기기를 검토해보고, 터치스크린에 적용 가능한 진보된 인터랙션 사례들을 조사하였다. 그 후 터치디스크린 기반의 디지털기기를 사용하는 사용자의 행태를 파악하기 위한 유저테스트 및 인터뷰를 실시하여, 터치스크린 기반의 모바일폰에서 구현되어야 할 상세 인터랙션 스타일을 도출하였다. 본 연구에서 제안된 인터랙션 스타일은 다양한 사용자 경험을 가능하게 하여 고기능, 고사양화 되어가는 모바일폰의 UI를 보다 효과적으로 사용하는데 도움을 줄 것으로 기대된다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.15-23
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• 2013

In this paper, we propose a session management and control architecture for N-Screen services, which enable users to change devices and transfer contents among user's devices during service by session transfer and split. In N-Screen services, users may have multiple devices with different attribute such as screen resolution, CPU capability and access network interfaces. Also, since users may change devices during service, or one user may use multiple stream, N-Screen services need to enable the user to share and transfer contents across N-Screen devices. We introduce the management and control servers to provide session split over user multiple devices and session continuity while changing device. Furthermore, the proposed architecture provides the device capabilities aware session continuity. In addition, the proposed scheme minimizes the session transfer delay and content server processing load. We present results that show the effectiveness and usefulness of proposed architecture.

• Journal of Bio-Environment Control
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• v.29 no.1
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• pp.52-61
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• 2020

The natural change of winter night temperature from 00:00 to 04:30 O'clock with the different height of thermal screen in a venlo type glasshouse (W59×L68×H5.9 m) was studied using computational fluid dynamics (CFD). At the early stage of CFD analysis, the room temperature decrease of glasshouse with the 5.9 m height of thermal screen were faster than it with the 4.1m height of thermal screen, but at 2 hr after analysis it was slower than in it with the 4,1m, the temperature difference was 0.6℃ after 4 hr. If we consider that turn on the heater when the temperature were decrease below 13℃ at 1hr after CFD analysis, it is good for energy saving in the glasshouse with the 4.1 m height of thermal screen rather than in it with the 5.9 m height, because of the temperature decrease were slow during 2 hrs after analysis. The airflow at the height of 2 m which were grown tomato were fast and wide in the glasshouse with the 5.9 m height thermal screen rather than in it with the 4.1 m, the speed difference was 0.034m·s^-1 at 1hr after CFD analysis. The effect of temperature decrease in summer season were compared with the different height of shading screen from 12:00 to 14:30 O'clock. The height of shading screen were 5.7, 3.9 m, the gap of it were 30%. The air-inflow quantity by the fan with duct at lower part of venlo glasshouse was 0.67 ㎥·s^-1 until 1hr and to increase 3 times of it from 1hr after analysis. The roof window were open 100%. Until 1hr of CFD analysis, the temperature in the 30% open of shading screen was 0.9℃ higher than in the none shading screen. From 13:00 O'clock when the air-inlet quantity to increase 3 times, the temperature in case 30% gap of shading screen were decreased compare with the none shading screen, the temperature difference was 0.5℃ at 14:30 O'clock. The temperature on the floor surface in case 30% gap of shading screen were lower with it's height increase, the temperature difference was 8℃ compare with none shading screen. The relative humidity difference were insignificant by the height and gap of shading screen.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.227-227
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• 2018

티롤리안 위어(Tyrolean Weir)는 유송잡물 및 유사의 영향이 비교적 높은 산악지역에 설치되는 취수구조물로 대부분 저류면적이 제한된 자류식(Run-Off River) 수력발전 및 소규모 농업용수 취수시설에 적합한 구조물이다. 티롤리안 위어는 일반적인 취수시설과 비교하여 구조물의 규모를 최소화할 수 있어 친환경적 취수구조물로 분류할 수 있다. 아직까지 국내에서는 설치사례가 없고 연구성과 또한 부족하여 적용성에 한계가 있는 것이 사실이다. 본 연구에서는 3차원 유동해석 프로그램인 FLOW-3D를 이용하여 티롤리안 위어의 월류흐름특성을 분석하고 스크린 경사와 월류수위 변화에 따른 유량계수를 산정하였다. 티롤리안 위어 스크린경사에 따른 수치모형실험을 위해 3차원 AUTO CAD 프로그램을 이용하여 위어폭 11.0m, 길이 10m 및 수로경사 2:3의 솔리드 모형을 구성하였으며, 티롤리안 위어 스크린 경사를 $0^{\circ}$, $5^{\circ}$, $10^{\circ}$, $15^{\circ}$, $20^{\circ}$, $25^{\circ}$, $30^{\circ}$로 변화시키며 월류수심 변화에 따른 수치모형실험을 수행하였다. 금회 수치해석 분석결과 다음과 같은 결론을 얻을 수 있었다. 1) 티롤리안 위어 스크린 경사가 증가할수록 유량계수가 증가하였다. 2) 월류수심 1.4m일때 월류량의 표준편차는 0.767이며 월류수심 4.4m일때 표준편차는 9.580으로 월류수심이 증가할수록 스크린 경사에 따른 표준편차는 증가하는 것으로 확인되었다. 3) 티롤리안 위어 스크린 경사가 클수록 월류수심은 감소하고 접근수로부 유속이 증가하였으며 스크린 경사가 작을수록 월류수심은 증가하고 유속이 감소하는 경향을 확인하였다. 4) 티롤리안 위어 스크린 경사가 작고 월류수심이 클수록 광정위어와 유사한 흐름특성을 보였다.

• 프린팅코리아
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• v.12 no.2
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• pp.102-107
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• 2013

한국인쇄학회는 지난해 11월 2일 추계학술논문을 발표했다. 추계학술논문에는 Reverse Offset에서 잉크전이 유동에 관한 시뮬레이션 연구, 그라비어 오프셋 인쇄에 의한 미세전극용 Ag Paste 개발, 국내 하프톤 스크린 인쇄를 위한 최적의 스크린 망사 선택 방법에 관한 연구, 친환경과 표준인쇄를 고려한 인쇄 최적화에 관한 연구 등이 발표됐다. 본지에서는 김준곤, 구철회, 조가람(부경대학교 공과대학 인쇄정보공학과)의 '친환경과 표준인쇄를 고려한 인쇄 최적화에 관한 연구'를 게재한다.

• 프린팅코리아
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• v.11 no.12
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• pp.116-119
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• 2012

2012년 한국인쇄학회 추계학술논문발표회가 지난 11월 2일 동국대학교 문화관 덕암세미나실에서 열렸다. 올해 창립 30주년을 맞은 한국인쇄학회는 이번 추계학술논문발표회에서 Reverse Offset에서 잉크전이 유동에 관한 시뮬레이션 연구, 그라비어 오프셋 인쇄에 의한 미세전극용 Ag Paste 개발, 국내 하프톤 스크린 인쇄를 위한 최적의 스크린 망사 선택 방법에 관한 연구, 친환경과 표준인쇄를 고려한 인쇄 최적화에 관한 연구 등을 발표했다. 본지에서는 김준곤, 구철회, 조가람(부경대학교 공과대학 인쇄정보공학과)의 '친환경과 표준인쇄를 고려한 인쇄 최적화에 관한 연구'를 게재한다.