• Design Convergence Study
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• v.15 no.5
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• pp.199-211
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• 2016

The study examined how age-friendly their living environments the aged perceived and it's significant difference depending on their characteristics. The subject were 96 old persons who aged more than 60 years and lived in Nagasaki city, Japan. They asked how far each neighborhood facility related to the aged was located from their houses, and the age-friendliness of walk way, traffic, multi-family houses for the aged, and interior space of their living houses. Data were collected by using one to one interview. Results were as follows: 1) Most neighborhood facilities related to the aged were located within a walking distance or 10 min. distance by bus from their houses. 2) Among 5 areas of living environments, while traffic, house interior, and pedestrians road were relatively age-friendly, the amount of multi-unit dwellings for the elderly and the usability of wheelchair users in house interior were not age-friendly. 3) Age and education level of the aged influenced on the age-friendliness of their living environments.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.327-330
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• 2006

Numerical study on the passive control of the oblique shock wave/turbulent boundary-layer interaction control utilizing slotted plates over a cavity has been carried out. Numerical results have been compared with the experimental observations, such as pitot/wall surface pressures and Schlieren flow visualizations, obtained for the same boundary conditions. It was found that the present numerical results shows a good agreement with experimental data. Further, the effect of different slot configurations including various number, location and angle of slots on the characteristics of the interactions are also tested, focusing on the variation of the piot pressure and the boundary-layer characteristics downstream of the interaction and the recirculating mass flux through cavity.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.12
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• pp.1223-1229
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• 2007

Flow traveling over a cavity opening forms a vortex due to unstable shear layer and induces an aerodynamic pressure excitation from the diffusion of the vortex convecting out of the trailing edge of the opening. The interaction between the excitation force and the cavity response sustains resonance in the resonator(cavity) and locked-in vortex shedding at the leading edge of the opening. The aerodynamic excitation force can be described from the diffusion of the vortex over the trailing edge and the level of its diffusivity is related to the strength of vorticity seeded at the leading edge. In this study, the control scheme of the internal pressure oscillation was proposed from regulating the vorticity at the leading edge by use of an oscillating spoiler. It was found that the relative motion between the spoiler and the air mass at the cavity opening influenced vorticity strength and the control was achieved by direct feedback of the cavity pressure fluctuation to the actuator.

• Journal of the Korean Solar Energy Society
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• v.22 no.4
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• pp.77-84
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• 2002

In order to investigate forced convection heat transfer due to the wind from the inner surface of a cavity receiver for a parabolic dish type solar energy collecting system, a two-dimensional rectangular cavity receiver is prepared and installed in a wind tunnel. The convection heat transfer coefficient of the inner surface of the receiver is dependent on the direction and the velocity of the wind. The attack angle of the cavity and the air velocity in the tunnel are controlled in a wide range so that the effects of the attack angle and the wind velocity on the heat transfer coefficient can be studied. The skirt is installed at the aperture of the cavity in order to reduce convective heat loss. The effects of the length and the installation angle of the skirt on convection heat transfer of the cavity are tested. It is found that convection heat loss can be significantly reduced by installing the skirt. Also, it is known that heat transfer from the cavity can be minimized if the angle of the skirt is $90^{\circ}$ to the outer surface of the cavity.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.124-127
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• 2001

가상현실 기술을 이용한 컴퓨터 지원 교육훈련 시스템 (VR-CATS: Virtual Reality based Computer Assisted Training System) 개발에 대한 연구를 전력연구원에서는 계속 수행해 왔다. 본 논문에서는 New VR-CATS (울진 3호기 참조)중 가상현실에서의 공동 협동 훈련 시스템(Virtual Reality Collaboration Training System)의 설계에 관하여 서술한다. 공동작업은 발전소 MCR(Main Control Room)을 3D 데이터 모델링 후 가상현실화하고 MCR 내부를 Navigation 할 수 있도록 가상패널(Virtual Panel)을 개발 및 에에 대한 엔지니어링 데이터베이스환경을 작성하여 추후 정확하고 신속한 계기 정보를 얻을 수 있도록 하며 훈련생들이 시뮬레이터실로 가지 않고 MCR에서 발전소를 운전하는 것과 같은 효과를 강의실에서 얻을 수 있다. 또한 설계기준사고 중의 하나인 LOCA 사고 복구 훈련 시나리오를 통하여 실제와 동일한 복구 훈련을 하므로서 효율적이며 현장감있는 교육훈련 수행을 가능케 한다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2009.04a
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• pp.346-351
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• 2009

본 연구에서는 화재시 많은 인명피해가 예상되는 공동 주택을 대상으로 단위공간별 화재 성상을 예측하기 위한 실물화재실험을 실시하였다. 구성된 실물화재모델은 비교적 가연물량이 많은 침실과 화재 발생 위험도가 높은 주방을 대상으로 하였으며, 실험 모델에 구성된 단위품목은 일반주택의 가연물을 선조사 한 후 선정하였다. 실험결과 침실의 경우 점화 후 약 5분이 경과되었을 때 플래쉬오버 상태에 이르게 되어 매우 급격한 성장을 보였으며, 최대 열방출율 약 7433.3 kW, 최대 일산화탄소 578.6 ppm, 최대 이산화탄소 1.25ppm, 내부 최대온도 1350$^{\circ}$로 측정 되었다. 특히, 화재 발생 초기에 가연 공간에서 화재의 진화가 이루어지지 않으면 약 3분 내에 인체에 급격한 피해를 줄 수 있는 한계온도 이상으로 화재가 성장하기 때문에 신속한 초기 대응이 필요함을 확인하였다. 이러한 실물화 재실험에서 얻어낸 결과는 향후 화재확대 예측 시뮬레이션 결과와 비교함으로써 각 용도별 공간에서의 화재 확산 예측에 적용 될 수 있을 것이다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.10a
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• pp.159-162
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• 2010

본 연구에서는 화재위험성이 높은 공동주택을 대상으로 실규모의 화재 재현 실험을 실시하였다. 여러 가지 발화 요인중 발생 빈도가 높은 6가지를 선정하여 재현실험을 실시하였으며, 실험결과를 토대로 화재감식 및 화재위험성을 분석하고자 하였다. 실험 결과 발화 후 약 4분이 경과후 화재가 빠른 속도로 성장하다가 5분경에 이르면서 내부로 화재가 완전히 전이 되는 것을 확인하였다. 화재시 발생되는 일산화탄소 농도는 최대 8200 ppm으로 측정되어 유독가스로 인한 질식사의 위험도 매우 높음을 보여주었다. 또한, 화재 현장의 화재감식을 실시함으로써 화재조사관의 현장 감식능력을 배양하고 화재조사경험 및 정보 공유를 위한 실질적인 기회를 제공하고자 하였다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.2
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• pp.117-124
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• 2007

An experimental research has been performed to evaluate the load transfer capacity for the planar joints between existing and new slab in an apartment remodelling constructions expecially for enlarging the interior space. Post-installed dowel bars were used as a joint connector. The existing slabs were obtained from the existing apartment housing which will be demolished, and were retrofitted with carbon fiber plate. Test results showed that the planar joints with post-installed dowel bars behaved in full composite modes until ultimate capacity of test specimens, so sufficient ultimate and serviceability performance are confirmed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.4
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• pp.400-406
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• 2017

The model used in this study was reversed to analyze the cause of excessive damage that occurred inside the rotating system and pipe system of a centrifugal-type seawater pump on a ship. For this purpose, internal flow analysis on a cooling seawater pump was performed using CFD. As a result, the shape and boundary conditions of the target pump were set by reverse engineering, and pump efficiency at a design operating point of $125m^3/h$ was calculated as 85.3 % with a head of 32.0 m. The maximum efficiency point of the target pump was estimated to be 86.2 % at $150m^3/h$, but this differed from the actual operating point. At $112.5m^3/h$, which was the lowest flow point, flow was unstable due to the characteristics of the low flow point and analysis convergence was not good. The purpose of this study was to clarify the cause of ongoing cavitation in seawater pumps and piping systems in operation. Future research will be needed to clarify causes for pipe systems in the future by performing calculations for the total piping system of an inlet and outlet, in addition to measuring the flow rate of each branch pipe.

• Journal of the Korean Geophysical Society
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• v.6 no.3
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• pp.139-153
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• 2003

Subsurface information is one of the most important factors in the archaeological excavation. To obtain the information on the underground, geophysical prospecting is becoming a popular method. This study is on the small rocky islands located 200m away from the shoreline of Gampo, Gyeongju city, Korea. According to the historical records and field surveys, it was revealed as the tomb of King Munmu of Shilla Dynasty. However, the questions and debates, such as whether it is really the tomb of King Moonmu or not, and whether it is a buried place or not, are still remains, in addition to the incompletion of precise surveying and scientific studies. The scope of this study contains the researches on the above problems and debates using the geophysical and geological methods and techniques. The rocky islands around the submerged Tomb of King Moonmu is composed of granite, and sag exists inside of the islands. Sea water enters through the east groove by wave and is drained to the west slot by hydraulic gradient, since west slot is 15cm lower than the east. Sag inside of the islands is believed to be extended and widened from pre-existed sinkage by applying tools like chisel in the joints and cracks. It is concluded that the submerged megalith inside of sag was from the rock block which was developed by joints. Geophysical surveys reveal that there is no artificial structure or stone/china/steel chest, under the m egalith and rocky island. Researches show that the tomb of King Moonmu was constructed in the small rocky island artificially. However, the evidences show that planners and constructors of the tomb made every possible effort to preserve the natural environment and condition. It is strongly believed that the megalith was sort of alter to sprinkle bone-ash rather than buried place.