• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.173.2-173.2
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• 2012

위성체가 발사체에 실려 발사될 때에 매우 높은 가속도에 의한 정적, 동적 하중 및 공기의 저항에 의한 하중, 연소 가스 분출시 발생하는 음향에 의한 하중, 발사체로부터 분리될 때 발생하는 충격 하중 등 여러 가지의 극심한 하중을 겪게 된다. 이러한 발사 환경에 대한 안정성을 검토하기 위해 발사체 업체에서 제공하는 매뉴얼 상의 설계 조건을 이용하여 설계하고 해석하여 검증한다. 천리안 위성의 후속 위성으로 해상도 및 채널 성능 향상된 차세대 기상탑재체를 탑재하는 정지궤도 복합위성을 개발 중이다. 임무 수명 기간을 연장할 수 있는 3.5톤급 혹은 그 이상의 플랫폼에 대한 형상 설계를 수행하였고 그 내용을 목적으로 한다.

• Aerospace Engineering and Technology
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• v.1 no.1
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• pp.55-64
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• 2002

A conceptual design of propulsion system for a geosynchronous communication satellite with 12 years design life is presented in this paper. Propellant mass budget for the design life is calculated using total velocity increment (ΔV) flowed-down from mission requirement analysis. Sizes of the fuel and oxidizer tank are derived based on the calculated propellant mass budget, and mass of the pressurant as well as the size and pressure of pressurant tank are calculated too. Thruster positioning, number of rocket engines, and position of tank are determined through Trade-Off Study with Structure & Mechanical Subsystem. Propulsion system configuration and its schematics are presented finally.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.9-9
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• 1998

다목적 실용위성의 궤도전이 및 위성체 자세제어를 위한 추진시스템의 설계요소에는 구조적 안전성, 우주환경에서의 열제어를 위한 회로 및 구성하드웨어 설계, 연료계통 맥압강하를 위한 장치설계 및 추력기 배기가스 영향을 고려한 형상설계 등이 있으며, 설계검증을 위해 부분해석이 수행된다. 또한 발사환경과 우주 궤도환경에서의 추진시스템 성능평가를 위한 연제어계 기능시험, 압력인증시험, 청정도시험 및 내부/외부 누설시험이 수행된다. 본 논문에서는 추진시스템 설계 및 조립공정에 대해 기술하였고, 시험분석을 통해 시스템의 설계 및 조립공정상의 신뢰성을 검증 분석하였다.

• Current Industrial and Technological Trends in Aerospace
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• v.3 no.1
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• pp.72-78
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• 2005

• Journal of the Korean Society for Railway
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• v.12 no.1
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• pp.39-44
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• 2009

The ballast-flying, induced by strong underbody flow of high-speed train, can damage train underbody, wheel and even cause the safety problems. For this reason, a heighter is being used to prevent ballast-flying through underbody flow reduction. In this research, flow field around a heighter is numerically simulated.. And the parametric study of various heighter geometries is performed to find out more effective heighter shape. Through these numerical studies, the relation between the heighter shape and underbody flow is found out. Also new heighter shapes are numerically investigated and their performances of underbody flow reduction are verified.

• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.87-93
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• 2011

FSSA(Fine Sun Sensor Assembly) is the important sensor for satellite attitude control. FSSA measures the direction of the sun's rays and determines whether the satellite is in the eclipse or not. FSSA for GEO Satellite is also used to acquire the attitude error information in the attitude control reference frame and acquire the Sun direction during transfer orbit or mission Process. This paper shows the configuration of Fine Sun Sensor for LEO and GEO Satellite and their principle of operation that angle measurement is obtained by using the transfer function which is the ratio of the difference between output currents of Solar Cell to the sum of all output currents.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.22-30
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• 2010

KARI had integrated and tested GEO satellite in cooperation with Astrium Inc., France. In the middle of integration and test, It was necessary to check GEO satellite SA(solar array) status and require electrical interface verification with bus. SA of GEO satellite have different mechanical characteristics in comparison with those of LEO satellite which was tested in KARI. LEO SA has been deployed by simple mechanical hinge system but GEO SA has been done by more complicated method. so in this paper, we designed the test configuration and analyzed the test result of solar array electrical integration of GEO satellite.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.11-17
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• 1998

In this study, a procedure is presented for the dynamic analysis of a multibody tracked vehicle system. the planner tracked vehicle model used in this investigation is assumed to consist of two kinematically decoupled subsystems, i.e., the chassis subsys- tem and track sub-system. The chassis subsystem includes the chassis frame, sprocket, idler and rollers, while the track subsystem is represented as a closed kinematic chain consisting of rigid links interconnected by revolute joints. The recursive kinematic and dynamic formulation module of the vehicle will be developed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.3
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• pp.75-82
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• 2019

Slab panels are very important to develop asphalt concrete (AC) track for minimizing the roadbed stress due to the train load and reducing the plastic deformation of infrared-sensitive AC. In this study, the slab panel for AC track was developed through the shape design and the indoor performance test and its structural integrity has been investigated through the finite element analysis under the flexural tensile stress and the design moment according to various static load combination by KRL-2012 standard train load model and KR-C code. In order to verify the suitability of the slab panel for AC track, static bending strength test and dynamic bending strength test were performed according to EN 13230-2. Results show that the slab panel for AC track satisfies all the performance standards required by European standards such as crack loads and crack extension.

• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.277-282
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• 2022

The sleeper floating track (STEDEF) in this study was a track type in which a very soft resilience pad was installed under a relatively thin concrete sleeper (RC Block). Therefore it was expected that the resilience pad could affect the estimation results of the concrete strength. In this study, field applicability evaluation was performed to apply the rebound hardness test method, which was a general method for estimating the compressive strength of concrete in civil structures, to concrete sleepers of railway tracks. In order to analyze the strength estimation technique of concrete sleepers reflecting the characteristics of track structures different from those of civil structures, the parameter experiments that could affect the strength estimation results of concrete sleepers in a serviced line were performed. As a result of the study, the appropriate hitting position was suggested considering the shape of the concrete sleeper, and the difference in strength estimation results according to the condition of the concrete sleeper and supporting conditions was derived.