• Journal of the Korean Geotechnical Society
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• v.32 no.1
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• pp.19-33
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• 2016

Stability analysis based on the limit equilibrium method combined with the result of infiltration analysis is commonly used to evaluate the effect of rainfall infiltration on the slope stability. Soil is a three-phase mixture composed of solid particle, water and air. Therefore, a fully coupled mixture theories of stress-deformation behavior and the flow of water and air should be used to accurately analyze the process of rainfall infiltration through soil slope. The purpose of this study is to study the effect of interaction of air and water flow on the mechanical stability of slope. In this study, stability analyses based on the coupled hydro-mechanical model of three-phases were conducted for slope of weathered granite soil widespread in Korea. During the process of hydro-mechanical analysis strength reduction technique was applied to evaluate the effect of rainfall infiltration on the slope stability. The results showed an increase of air pressure during infiltration because rain water continuously displaced the air in the unsaturated zone. Such water-air interaction in the pore space of soil affects the stress-deformation behavior of slope. Therefore, the results from the three-phase model showed different behavior from the solid-water model that ignores the transport effect of air in the pores.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.71-77
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• 2010

As a hybrid model of continuum motion description which combines the advantages of classical kinematical descriptions i.e. Lagrangian and Eulerian description, the ALE (Arbitrary Lagrangian Eulerian) description is adopted for the simulation of a fluid-structure interaction of solid propellant rocket interior. The fluid-structure interaction phenomenon with the deformation of solid domain during the simulation. The developed solver is applied flow and propellant structure. The computed results show complex flow physics in the combustion chamber and the behavior of a solid propellant deformation.

• Journal of Aerospace System Engineering
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• v.13 no.6
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• pp.43-51
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• 2019

The aircraft vertical acceleration from the excitation of the road surface in the taxing mode is a main factor with a negative effect on the boarding quality of pilots and passengers. In this paper, we propose an appropriate control method to improve the boarding quality of the MR damper landing gear. The proposed control method is Skyhook Control Type 2, which feeds the aircraft vertical acceleration back in addition to the aircraft vertical velocity. Since Skyhook Control Type 2 factors the velocity and acceleration of the upper mass, it can be expected to exceed the control performance of the existing Skyhook Control that factors only the upper mass velocity. For the simulation, the bumper type road surface was selected as a ground surface, and the landing gear model constructed with RecurDyn and the controller designed with Simulink were co-simulated. The control effect of Skyhook Control Type 2 was verified by comparing and analyzing the RMS and maximum value of the upper mass acceleration according to the taxing speed and control method.

• Journal of Aerospace System Engineering
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• v.12 no.3
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• pp.64-69
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• 2018

The high-velocity electromagnetic forming (EMF) process is based on the Lorentz force and the energy of the magnetic field. The advantages of EMF include improved formability, wrinkle reduction, and non-contact forming. In this study, the electromagnetic-structural interlocking analysis was performed in order to analyze the moldability of aluminum pipe using electromagnetic molding. The magnetic flux density was decreased due to increasing electrical resistance as the temperature increased, and the stress-strain curve decreased. The higher the temperature, the lower the flow stress, increasing deformation.

• Journal of the Korea Computer Industry Society
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• v.5 no.9
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• pp.1017-1024
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• 2004

In this paper, we propose the progressed interworking method between H.323 and SlP, then explain the improved property. The VolP(Voice over Internet Protocol) technology which is able to use a voice service through internet is more cheaper then existing telephone charges, and is easil)· accept the various of multimedia services from internet. Previous connectionmethod of VoIP used H.323 protocol, but it is very complex to connection establishment. so, the SIP(Session Initiation Protocol) protocol that propose in SIP-Working Group is in use recently. Therefore, we need new interworking methodology between H.323 and SIP Products. In this thesis, the progress interworking method between H.323 and SIP are Propose, then interpret unnecessary packet delay for call setup and improved feature of message exchange.

• Journal of the Korean Society for Railway
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• v.13 no.2
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• pp.194-200
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• 2010

Recently, a longitudinal tunnel construction has increased because of subway construction extension, geomorphological effect and the development of construction Technologies etc. When the fire occurs in a tunnel and an underground structure, the many damage of human life and the economic losses are caused. In Korea, fire resistance character study of a tunnel and an underground structure is proceeding. However, when a concrete is exposed to high temperature, study of load carrying capacity reduction and stability evaluation for spalling of a concrete is not enough. Therefore in this study, fire resistance character of a concrete evaluated according to time heating temperature curve(RABT and RWS) and a result compared on virtual fire accident in order to apply fire scenario. Also this study performed thermo-mechanical coupled analysis of a FEM-based numerical technique and estimated fire-induced damage of a tunnel and an underground structure.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.3
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• pp.24-33
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• 2014

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1998.10a
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• pp.307-310
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• 1998

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.05a
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• pp.171-172
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• 2016

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.392-397
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• 1997

고리 2호기 주급수 차단밸브의 경우 다른 호기와는 달리 구동용 질소압력 측정스위치에 의한 닫힘 연동신호가 설치되어 있다. 이러한 연동신호는 벨브 구동용 반구내 질소 압력 스위치 "고" 오동작에 의한 밸브차단 가능성이 있으며 이 경우 질소압력스위치가 저/고 경보창에 COMMON되어 있어 원인 규명에 어려움이 있다. 또한 질소압력 스위치 고장 및 질소가스 누설시 작업수행이 어렵고 위험이 따른다. 이러한 70년대 발전소 설계의 과잉설비를 제거하므로서 최적운전과 경제성 향상에 기여할 수 있으며 아울러 유지정비의 용이성과 밸브 불시닫힘을 미연에 예방할 수 있으리라 예상된다. 이와 관련하여 발전소 계통안전성, 기기안전성을 평가한 결과 기존의 안전해석결과가 유효하며 또한 FSAR 수정없이 이러한 설비변경이 가능하다는 결론에 도달하였다.결론에 도달하였다.