• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.693-694
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• 2012

• Journal of Korean Society for Quality Management
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• v.45 no.4
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• pp.981-994
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• 2017

Purpose: In this study, the reliability growth management procedures for armed vehicle is suggested and an illustrative case study of launcher system is given. Methods: Crow-AMSAA model is adopted to manage reliability growth of armed vehicle using failure data acquired from development test phase to field operation phase. Between the development test phase and the production phase, the suggested reliability growth procedures for armed vehicle entails accelerated life test of the selected module whose design is changed to improve its reliability for assuring the target system reliability. And it can be verified through estimating the system reliability based on the failure data of field operation phase. Results: It is shown that the proposed reliability growth management procedures are effective for armed vehicle based on the case study of launcher system. After estimating the reliability of launcher system at every development test, some items are selected to change their designs for improving reliability. Accelerated life test is performed to prove the reliability improvement and finally it is verified through the field operation. Conclusion: The reliability growth management procedures for armed vehicle is suggested and the case study of launcher system shows it can be effective for managing the reliability growth of the armed vehicle.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.73-74
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• 2015

In the world the interests about a unmanned surface vehicle(USV) are growing up. However it is difficult to launch and recover a USV because of no men on board of USV. And it is more difficult in recovery than launch of USV. So in this research the heaving line launcher was developed to support the recovery of USV easier. And a mock-up was manufactured to validate for adoption to the USV. The muck-up is composed of launcher pipe, remote trigger, air tank, tow shell and heaving line. Tests in land using the mock-up were carried out. The forces by the heaving line launcher to USV were measured by a measuring table during the tests in land. In this paper the development of a mock-up of heaving line launcher, tests in land and the measured forces during tests are presented.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.3
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• pp.101-112
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• 2021

SpaceX shows various strategies such as constructing various payload portfolio through the reuse of Falcon 9 and Falcon Heavy, constructing the launch vehicles using one type of engine, the transition from kerosene engine to methane engine, and the use of 3D printing. In this study, launch vehicle proposals that can cover a variety of payloads and trajectories from KOMPSAT to GEO-KOMPSAT were constructed, and ten launch vehicles using kerosene gas generator cycle engine, kerosene staged-combustion cycle engine, and methane staged-combustion cycle engine were reviewed. Of the ten launch vehicles, the reusable launch vehicle using a 35-ton methane engine was rated as the best in terms of development potential.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.3
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• pp.32-42
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• 2022

The strategy to develop a launch vehicle family by bundling multiple rocket engines of a single type has been proven by SpaceX and their reusable fleet comprised of Falcon 9 and Falcon Heavy. In this study, we revisit a potential launch vehicle family out of a 35 tonf-class methalox staged combustion cycle engine and evaluate their utility and performance in various space missions. For example, a Korean version of Falcon 9 can deliver 4.7 tons of payload into 500 km SSO in an expendable mode while the payload is reduced to 2.16 tons in a sea-landing reusable mode. A Korean version of Falcon Heavy can deliver 4.4 tons into GTO when launched from the Naro Space Center, indicating that this common booster core configuration can handle Cheollian 2 albeit the high inclination. Once developed, the same methaloax engine can power the first-stage of smallsat launch vehicles and air launch vehicles.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.5
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• pp.494-501
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• 2020

When we develop an OpenGL-based coastline map that displays the high resolution data of GSHHG, it takes tens of seconds until the first scene is rendered. That is because it takes time to tessellate polygons with a huge number of vertices. A commonly used solution is that it converts original data to a customized data in advance, and it displays these. But if we should use original data to display a coastline map, we need to find another solution. In this paper we suggest using a polygon splitting technique to minimize tessellation time. In order to prove its effectiveness, we implemented a software applied this technique and measured its performance. The software applied this technique took a few seconds to display the first scene and we confirmed its effectiveness.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.402-404
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• 2006

Electro-magnetic launcher(EML)는 전자기력을 이용하여 발사체를 추진시키는 장치이며 그 종류에는 레일건과 코일건이 있다 본 논문에서는 소형, 경량의 발사체를 추진, 가속시키기 위한 솔레노이드형 EML을 설계, 제작하여 시험 발사하고 그 특성을 분석하였다. 개발된 EML은 소형이기 때문에 launcher의 직경이 작아 자기장을 한 지점으로 집중시키는 장치가 필요없고, 전기에너지를 줄이기 위한 별도의 시스템이 필요하지 않으며, 솔레노이드의 형태와 발사체의 위치, 스위칭 시간에 의해 발사체의 추진력과 속도를 조절할 수 있는 장점이 있었다.

• Journal of Korean Society for Quality Management
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• v.46 no.3
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• pp.411-424
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• 2018

Purpose: The purpose of this study is to improve submarine TACM launcher system safety device performance. Methods: In this study, EPLD(Electrically Programmable Logic Device) control and time sharing method to the safety device actuator motor and discrete signal processor in launch control panel were used to resolve unusual performance of safety system. Results: The result of this study are as follows; First, sporadic stopping of safety device actuator motor due to insufficient In-Rush current was resolved. Second, repeat of safety device condition as lock & release due to chattering for motor activating was resolved. Third, simultaneous release function for safety device actuator was available. Conclusion: The unusual performance of function for submarine TACM launcher system was overcame by applying EPLD control and time sharing method. The suggestions were proved by performance test in the pressure chamber. The results of this study enhanced survivability of ${\bigcirc}{\bigcirc}{\bigcirc}$ class submarine from enemy torpedo.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.5
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• pp.634-644
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• 2001

The test facility of a 1/60-scale model for train-tunnel systems has been recently developed to investigate the effects of tunnel portal shapes, hood shapes and air-shafts for reducing the micro-pressure waves radiating towards the surroundings from the tunnel exit. The present test rig has been advanced from a 1/70-scale facility at NLR in Netherlands. The NLR test rig has the two-wise guidance system that needs two ears attached on the external surface of a model train nose. Therefore, their train models have irregular nose shapes. The main characteristics of the present facility are that the train model is guided by only one wire from the compressed air launcher to the absorber parts of test facility and the wire guidance hole is located at the axial center of a train model. In the present test rig, after a train model is launched, the air jet from the launcher does not enter the tunnel model. Experimental results were compared with numerical predictions to prove the performance of the test facility.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.198-203
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• 2004

Ocean developments gradually move to deep-sea in the 21 century. A deep-sea unmanned underwater vehicle is one of important tools for ocean resource survey. A marine cable plays an important role for the safe operation and signal transmission of a deep-sea unmanned underwater vehicle. The first cable of a deep-sea unmanned underwater vehicle is excited by surface vessel motion and shows non-linear dynamic behaviors. A ROV launcher is also excited by the 1st cable motion. A numerical method is necessary for analysing the dynamic behaviour of the first marine cable and the ROV launcher. In this study, a numerival program is appled to a 6,000m long cable for a deep-sea unmanned underwater vehicle to shaw shows the dynamic behaviour of the cable and the ROV launcher under combined excitations.