• Current Industrial and Technological Trends in Aerospace
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• v.9 no.1
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• pp.102-109
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• 2011

NEOs are comets and asteroids that have been nudged by the gravitational attraction of nearby planets into orbits that allow them to enter the Earth's neighborhood. When the NEOs with certain size impact in the Earth's surface, it could cause a serious disaster. However, the NEOs that are potentially the most hazardous because they can closely approach the Earth are also the objects that could bemost easily exploited for their raw materials. This paper presents the characteristics of NEOs and the technology trend of advanced countries on spacecraft missions to comets and asteroids.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.796-801
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• 2006

Smart열차진로제어시스템은 실시간 열차속도와 열차위치정보를 토대로 진로제어구간을 진입 또는 진출하는 해당 열차의 진로를 제어한다. 현재 운용중인 열차진로제어알고리즘은 궤도회로를 이용해서 검지한 열차점유정보를 사용하고 있으므로, 새로운 개념의 알고리즘개발이 필요하다. 이를 위해서 다양한 형식의 열차가 감속성능을 구현할 수 있는 전동기와 구동장치를 사용하는 모의장치의 개발을 완료하였다. 모의장치는 무선통신기반의 간선철도용 열차진로제어시스템개발을 목적으로 하고 있으나, 알고리즘개발의 효율성과 편리성을 갖추기 위해서 ATS(Automatic Train Supervision), ATC(Automatic Train Control) 및 ATO(Automatic Train Operation) 등의 기능을 구현할 수 있도록 모의장치를 개발하였다. 본 논문에서는 모의장치 구성, 모의장치의 하부장치별 기능 및 각 하부장치에 설치되어 있는 프로그램구성을 다루고 있다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1995.11a
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• pp.87-96
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• 1995

인공위성의 궤도진입에 사용되는 액체추진제 로켓엔진의 개발에서 분사기 설계를 적절히 수정, 보완 할 목적으로 수행된 핵심부품별 유동해석의 내용이 기술되었다. 단일 격자계를 구성하기 어려운 복잡한 형상의 분사기 유동장에 대한 격자계 구성을 용이하게 하고, 3차원의 점성 유동해석을 컴퓨터 기억 용량에 제한없이 수행하기 위한 다중블럭 격자기법이 사용되었다. 분사기의 내부유동은 3차원 비압축성 Navier-Stokes 방정식으로 pseudocompressibility 방법을 이용하여 수치모사되었다. 정상상태의 해는 근사 인자분해에 의한 ADI 기법으로 계산되고, 공간미분항에 대해 nonstaggered 격자계에서 2차 중앙차분을 사용하며 수치해의 안정성을 위해 인공점성항을 추가하였다. 난류계산을 위해 Baldwin- Lomax의 대수적 난류모델에 다수의 벽면효과를 고려하였다. 해석결과는 분사기의 성능에 영향을 미칠 수 있는 유동조건에 따라 분석되었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.81-81
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• 2022

서북태평양은 전세계적으로 태풍이 가장 많이 발생하는 해양 지역 중 하나이다. 태풍이 몰고 온 강풍과 폭우, 폭풍해일 등은 우리 사회경제와 환태평양 국가의 신변안전에 심각한 위협이 되고 있다.특히 내륙으로 진입하는 수백킬로의 영향을 미치는 만큼 넓은 지역에 걸쳐 강우량이 발생하고, 집중강수 기간이 짧아 산사태 등 자연재해로 많은 인명피해가 발생한다. 이러한 피해를 줄이기 위해서는 태풍의 활동특성을 잘 파악하고 태풍에 의한 강수량 예측 연구가 재해예방과 재난저감을 위해 필요하다. 그러나 현재기술에서 태풍이 몰고 온 강수의 정확한 양적 예측은 여전히 어려운 문제이며, 해결해야 할 큰 도전과제이다. 본 연구에서는 태풍별 강수량 상관관계를 분석하고, 서북태평양의 역사적 태풍의 궤도와 강도를 고려해 태풍으로 인한 강수량을 예측하는 통계적 방법을 적용한 결과를 제시하고자 한다.

• Journal of the Korean Society for Railway
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• v.18 no.1
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• pp.8-14
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• 2015

This paper describes a prediction method for micro-pressure wave emitted from a tunnel on the Kyung-bu high-speed railway. Pressure and micro-pressure wave were measured simultaneously to obtain some constants for the prediction method. The change of a micro-pressure wave were analyzed according to the speed of the train, the track bed type, and the distance from a tunnel portal. At a train speed of 300km/h, the micro-pressure wave of 4.0km long ballast track tunnel is about 7.5Pa; that of 3.3km long slab track tunnel is about 14.3Pa The strength of the micro-pressure wave decreases in inverse proportion to the distance and becomes about 0.5~1.0Pa at a point of 100m from the tunnel exit. Micro-pressure waves were predicted using the formula with the obtained the constants. Using a comparison between the predicted data and field measurement data, it was confirmed that micro-pressure wave can be predicted easily through the prediction formula.

• Journal of Korean Society of Transportation
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• v.30 no.4
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• pp.21-32
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• 2012

Exclusive bus lane (EBL) is typically located in the roadway median, and is accessed by weaving across the GPLs(general purpose lanes) before entering from the left lane of the GPLs. To maximize the potential for successful EBL operations, a critical design issue that requires special attention is the length of bus weaving section before entering EBL. The process of developing guidelines for the length of bus weaving section can be supported by a sensitivity analysis of performance measure (safety) with respect to the bus weaving distance. However, field data are difficult to obtain due to inherent complexity in creating performance measure (safety) samples under various interesting flows and bus weaving distance that are keys to research success. In this paper, VISSIM simulation is applied to simulate the operation of roadway weaving areas with EBL, and based on vehicle trajectory data from microscopic traffic simulation models, the Surrogate Safety Assessment Model (SSAM) computes the number of surrogate conflicts (or degree of safety) with respect to the bus weaving distance. Then, a multiple linear regression (MLR) model using safety data (number of surrogate conflicts) is developed. Finally, guidelines for bus weaving distance are established based on the developed MLR. Developed guidelines explicitly indicate that a longer bus weaving distance is required to maintain desired safety as weaving volume increases.

• Journal of the Korean Society for Railway
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• v.15 no.1
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• pp.37-41
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• 2012

Kyung-Bu High Speed Railway is operated in train control system(tcs) of fixed block operated in a way of dividing track circuits into several blocks in accordance with operation circumstances such as rolling stocks, grade, curves and facilities. The TCS of fixed block system refers to a continuous train control system, which transfers operational information such as entry and exit speed, distance-to-go, and deceleration etc. into on-board train control equipment on the basis of block occupancy of a preceding train. It guarantees a safe operation of trains by giving an emergency braking order, in case that a train exceeds an entry and exit speed of a corresponding block. In this paper, we analyze the speed control code deducing in accordance with maximum operation speed and characteristics of rolling stocks by analyzing principles of generation of speed control code allocated in blocks for safe operation, then train operational efficiency was analyzed by means of analysis of operation headway in accordance with the deduced speed control code. This study will be used to design in case of getting an increase in speed for existing high speed line or new high speed line TCS.

• Current Industrial and Technological Trends in Aerospace
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• v.7 no.2
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• pp.3-11
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• 2009

On August 25th, Korea launched KSLV-1(Naro), the first Korean launch vehicle with the payload of a small satellite. The launch itself was successful in that the first and second stage of the launch vehicle functioned properly but unfortunately the satellite was unable to be put into earth orbit due to the failure of a nose faring detachment. As the history of human space activities shows, it is recognized as a difficult task to be a launching state requiring efforts to obtain enough technical ability. But along with the technical ability, there has to be an understanding on international legal systems on space launch vehicle. It is because the launch may cause cross-border losses and because the launcher is regarded as a strategic technology resulting in international control. This paper aims to study the international status of launching state and to consider legal regimes necessary for launcher development.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.8
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• pp.654-660
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• 2014

In this paper, a conceptual design of a launch vehicles is proposed by combining Naro-1 and KSLV-II. For trans-lunar injection (TLI) to lunar orbit at 300 km LEO, the target performance is defined same as that of KSLV-II, which delivers an object of 2.6 tons into 300 km LEO. The proposal launch vehicle concept of this study is combination of 1st stage of KSLV-I and 2-3rd stage of KSLV-II. Thus, it is possible to reduce the development time and also could expand the options for national launch vehicle capabilities with proven technologies.

• Current Industrial and Technological Trends in Aerospace
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• v.8 no.1
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• pp.55-61
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• 2010

Thermal vacuum test should be carried out to verify the performance of the S/C on the ground under the simulated space environment. KARI already completed the construction of a Large Thermal Vacuum Chamber(LTVC) with 8 m of diameter and 10 m of length dimension. LTVC is for the purpose of performing the orbital environment test for large Space Craft(S/C). Inside LTVC, S/C is much smaller than LTVC. For the function test of S/C during the thermal vacuum test, the S/C has to be connected to Electrical Ground Support Equipment(EGSE) which includes several cable and RF wave guide inside LTVC. Also, MLI should be installed on S/C before the test. But it is very difficult to access the S/C inside big LTVC. To solve the accessibility to the S/C inside LTVC, KARI designed an access fixture. This fixture provides easy access to the any S/C thus can help safe installation and saving time for the related work inside LTVC. This paper describes whole process for the design of the access fixture.