• Journal of the Korea Society of Computer and Information
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• v.4 no.1
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• pp.92-98
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• 1999

Interpersonal trust is the mutual "faithfulness" on which all social relationship ultimately depend and applicable to the relations among people rather than to their psychological states taken individually. Recent development in the organizational sciences reflect the importance of interpersonal trust relationships for sustaining individual and organizational effectiveness, researchers have recongnized trust's influence on coordination and control at both institutional and interpersonal levels of organization. Because economic action is embeded within networks of social relationships. researchers have argued that efficiency within complex systems of coordinated action is only possible when interdependent actors work together effectively. Thus, for managers and professionals in organizations, developing and maintaining trust relationship is especially import. The purpose of the present study is to investigate the mechanism of interpersonal trust in the organization. Especially, the major concern of this study is to verify role of interpersonal trust in the member's task behaviork behavior

• Journal of Ocean Engineering and Technology
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• v.15 no.3
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• pp.134-141
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• 2001

An experimental method to investigate the dynamic characteristics of buoys in extreme environmental condition is established. Because the buoy model requires a resonable size for accurate experiment, the test condition in model basin that satisfies the similarity law is hardly compatible with capability of test facilities. It is suggested that the linear wave component that is unable to satisfy similarity is separated with others. The model experiment is carried out with mitigated condition for the linear wave components while others including wave drift, current and wind are keeping the similarities. Then, the result can be extrapolated to give the dynamic behavior of buoys n extreme condition because linear wave component is solely responsibly to oscillatory buoy motion and other environmental components are applied as a initial tension. The similarity for current and wind conditions is viewed as equivalence of restoring forces. The validity of proposed method is examined with different types of standard ocean buoys and it indicates that the linearity of measured characteristics is assured with a limitation of resonable distance between test and estimated wave conditions.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.344_346
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• 2009

본 논문에서는 전력계통에서 고장발생시 자속의 변화를 통한 magnetic switching을 이용한 전류제한기를 제안하였다. 구조는 자속이 흐를 수 있는 철심과 회로에 연결되어 있는 1차권선, 철심과 1차권선 사이에 위차한 1차권선과 반대방향으로 감겨져 있는 2차권선 및 2차권선 하부에 이동이 가능한 동판의 2차권선 secondary로 구성되어 있다. 정상상태에서는 철심내에 1차권선과 2차권선에 의해 발생된 자속이 서로 상쇄되어 두 권선에 유기되는 전압은 0이지만 고장이 발생하여 2차 권선의 스위치를 open하고 2차권선 secondary를 철심밖으로 쳐 내면 그동안 상쇄되었던 자속이 철심을 통하여 흐르게 되고 이에 따라 1차권선에 유기된 전압은 회로의 전류를 제한하게 되므로 차단기를 용이하게 동작시킬 수 있는 구조이다. 실험을 통하여 전류제한기 동작 전 후의 전류제한 효과를 분석하였으며 이를 통해 본 논문에서 제안하는 시스템은 차단기에 가해지는 아크충격을 완화하여 설비의 수명을 연장하고 적은 용량의 차단기 사용이 가능하므로 설비투자예산 절감 및 모든 차단기 사용분야에 활용될 수 있는 장점을 가지고 있음을 확인하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.1
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• pp.43-48
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• 1997

The present study is aimed to investigate experimentally on the hydrodynamic behaviours of air ~ pulverized coal flow in rectangular combustor with cavity. Mean velocity, density and tur¬bulent properties of pulverized coal in rectangular entrained flow combustor were measured by PDA. Experimental results show that the flow reattachment point at the lower plane in the com¬buster chamber has been developed near X/D= 15. The similarities at each section are found after the flow reattachment point. The maximum values of turbulent intensity and Reynolds shear stress have been shown near Y/D=6, which is higher than centerline. The maximum density of the pulverized coal sited in the range ofY/D=6~8.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.3
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• pp.8-17
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• 2015

In this research, low fidelity air/heat load analysis was conducted for the intake of high speed vehicle. For air/heat load calculations, aerodynamic properties at the surface and the boundary layer edge were estimated using Taylor-Maccoll equation for conical flow, shockwave relation and Prandtl-Meyer expansion equation for internal and external flow. Couette flow assumption and Reynolds analogy were used in order to calculate convective heat transfer coefficient. In order to calculate skin friction coefficient for heat transfer coefficient analysis, Van Driest method II and Reference Enthalpy method were considered. An axis symmetric SCRAMJET model was selected as a reference configuration for verifying the proper implementation of the present method. Comparison of the results using the present method and Computational Fluid Dynamic analysis showed that the present method is valuable for efficiently providing pressure and heat loads for air-intake structure design of the high speed air vehicle.

• Proceedings of the Korea Water Resources Association Conference
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• 1986.07a
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• pp.131-145
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• 1986

흐름수역에서 연직상향으로 방류되는 평면부력\ulcorner의 거동이 연속방정식, 운동량방정식 및 추적물수송식의 기본방정식에 의하여 수치적으로 해석된다. 난류확산에는 Prandtld의 혼합거리이론을 도입한 난류수송모형이 이용된다. 수치해 과정은 기본방정식을 유함수(stream function)식, 와도수송(vorticity transport)식으로 변환한 후, \ulcorner방류속도와, 방류구폭 등으로 표현되는 변수와 흐름을 지배하는 무차원 매개변수를 도입하여 무차원 형태로 표현하는 부분과 successive under-relaxation과 Gauss-Seidel반복법으로 수행하는 부분으로 이루어진다. 적절한 relaxation 계수를 선정하므로써 안정되고 수렴성이 좋은 계산이 수행된다. \ulcorner방류 속도와 가로흐름 속도의 비가 속도비(Velocity ratio)로 정의되며 속도비가 8 - 15의 범위에서 부력\ulcorner으로 인한 주변흐름수역의 속도변화 온도상승범위, 흐름상태(유선) 및 와도가 조사되었으며 \ulcorner의 경로에 대하여 속도비와 방류밀도후르드수의 영향이 또한 조사되었다. \ulcorner중심선의 속도와 온도변화, 국부밀도후르드수의 변화가 구해지며 퍼짐율(dispersion ratio), 확산비(spreading rate)가 방류밀도후르드수, 국부밀도후르드수 및 방류구로부터의 경로의 항으로 해석되었다. 또한 속도와 온도 분포에 상사(similarity)가 존재함이 밝혀졌으며 본 연구와 같은 조건의 범위에서는 Gaussian분포를 이용한 적분형해석(intergal type analysis)이 가능한 것으로 사료된다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.11-14
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• 2006

This study investigates the flow field of multiple-jet measured by hot-wire anemometry. The experiments were classified into two cases; 6- or 7-nozzle located circumferentially in equal interval without or with a central jet. The effect of the number of nozzles the flow field was examined when the Reynolds number based on the nozzle diameter is about $10^4$. Mean Velocity, normal and Reynolds stresses were measured in the downstream of jets. The Tollmien's theory holds far downstream at 48d apart from the nozzle exit especially when a nozzle locates at the center. The general flow characteristics is influenced due to the number of nozzles.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.82-85
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• 2009

In the development of Liquid Rocket Engine(LRE) systems, it is essential to understand the spray characteristics which influence mainly the performance and the stability of combustion. The injectors for this study have a recessed Liquid-swirl/Gas-centered jet coaxial type. For the similarity with actual conditions, the experimental conditions are calculated by using the momentum ratio as a matching parameter, and the stimulants of fuel and oxidizer are gaseous nitrogen and water respectively. The spray fields were measured by means of a photographic technique. Moreover, an effect of the momentum ratio has been investigated.

• Magazine of the Korea Concrete Institute
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• v.5 no.1
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• pp.115-127
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• 1993

본 연구의 목적은 프리캐스트 콘크리트(P.C) 대형판 아파트 구조물에 대한 우리나라 내진설계기준안 및 지침을 수립하기 위해 필요로 하는 정보를 취득하는데 있다. 이것은 실제 지진과 유사한 진동을 발생시키는 진동대를 사용하여 P.C대형판 구조물의 거동을 분석관찰함으로써 달성되었다. 여기에 사용된 시험체중의 하나는 습식접합 1/3 축소 3층 입체 P.C모델이었다. 지진파를 일으키기 위해 4mx4m 크기의 진동대가 사용되었다. 또한 선택한 입력지진가속도파는 Taft N21E 성분기록지진파로서 최대지진가속도(PGA)는 원하는 지진세기수준에 따라 조정되었고 시간축으로는 동적상사성법칙에 따라 축소되었다. 이 P.C모델의 진동대 실험을 통해 얻은 결과를 근거로 하여, 근거로 하여 다음과 같은 결론을 도출하였다. (1)이 시험체에 관한한, 지진안전계수는 7-8정도로 나타났으며, (2)이 P.C모델이 감쇠계수는 대체로, 철근콘크리트구조물 감쇠계수의 두배에 해당하는 값인 8%정도이며, (3) 이 모델은 접합부의 벌어짐과 미끄러짐에 의한 에너지소산을 통해서 2-3정도의 전체적인 변위연성비를 보여주었다.

• Journal of Ocean Engineering and Technology
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• v.21 no.6
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• pp.101-106
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• 2007

In this paper, the authors demonstrate a new idea to take the place of the real pressure vessel test, which should be carried out in a high pressure experiment unit before the real sea trial test. The idea is to make a pressure vessel model as a replica of the real pressure vessel test, which can reduce the cost of making a pressure vessel and large pressure experiment unit. The pressure vessel model was designedbased on linear-elastic, buckling equations and Finite Element Analysis. The manufactured pressure vessel model was investigated and monitored while the pressure test was being conducted. After the test, the result and the validity of the pressure vessel model as a replica of the real pressure vessel test was studied.