• 항공우주시스템공학회지
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• 제6권3호
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• pp.34-39
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• 2012

In this paper, analysis of airworthiness requirements which require flight test to show compliance and flight test method as means of compliance to those requirements are provided. For unusable fuel test, sufficient discussion between certification authority and applicant is required to select test conditions. For hot weather fuel system operation test, preservation and heating of test fuel should be done carefully not to adversely affect to test result.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.83.1-83.1
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• 2010

A Dead-end mode operation is one of the best way to maximize the gas usage rate. But, some components of fuel cell stack like gas diffusion layer(GDL) or membrane can be damaged in dead-end mode operation. In this study, a Large Scale Polymer electrolyte membrane fuel cell(PEMFC) for a dead-end operation has been developed. The stack is composed with 4 cells which has over 400cm2 of active area. Hydrogen is used as a fuel, and oxygen is used as a oxidant. The dead-end operation performance was evaluated by a long-term dead-end mode operation. The fuel cell stack is operated over 1,500 hours in dead-end mode operating fuel cell test station. And the performance change of the fuel cell stack was investigated.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.209-214
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• 2007

This study is concerned with working hardening of bending operation on hydroforming parts. Generally, hydroforming parts having the complicated shape of the automobile, require a 3-dimentional bending operation. This operation involves several variations in the tube which are the thickness, the mechanical characteristics, the hardness, the circumference etc., on original tube. So, we study those variations and the affect on the hydroforming operation and hydroforming parts. We used two methods, one of which was computer simulation and the other the actual test in the plant.

• 설비공학논문집
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• 제11권3호
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• pp.401-413
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• 1999

An ice storage cooling facility with cooling capacity of 150㎾ has been constructed for the purpose of developing optimal design and control strategy for an ice storage system. As the first step to this purpose, a computer program has been developed to simulate the operation of the ice storage system and examined precisely by comparing the results with those measured from the test facility. With the simulation program verified from the comparison, a design procedure has been developed to determine the minimum capacity required for each operation strategy available commercially. It is shown that the minimum sizes of the chiller and the storage tank are strongly dependent on the control strategy, i.e., chiller priority or storage priority, but less affected by the arrangement method, i.e., chiller upstream or chiller downstream.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.151-156
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• 2003

The Communication Based Train Control(CBTC) System generally used to improving existing lines in the world is efficient and stable for improvement. Also it is efficient for improvement because it does not cause any problems in operation of existing lines. We examined the mixed operation scheme for more efficient and stable improvement when improvement is implemented depending on aged equipment and the increased number of passengers in the Korean city railroad. The biggest point in the mixed operation is to implement a stable test without interfering with the operation of the existing lines. For this purpose, we deduced a method of installing the equipment, a method of testing depending on the installed equipment, and the types of mixed operation, and presented a scheme of execution of the methods depending on the mixed operation.

• 전력전자학회논문지
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• 제26권4호
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• pp.263-270
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• 2021

Active AC/DC converters with PWM operation are utilized to regulate rectified DC bus voltage of a permanent magnet synchronous generator in the maritime DC power system. A DC bus voltage regulation strategy that exploits the six-step operation is proposed in this study. Compared with that of the PWM operation, switching loss of the converter can be significantly reduced under the six-step operation. Moreover, conduction loss can also be reduced due to the high modulation index and reduced flux-weakening current of the six-step operation. A controller is used for the proposed DC bus voltage regulation strategy to verify its validity with the simulation and experimental setup. The simulation and the experimental test results showed that the converter loss reduces to a maximum of 70% and 19%, respectively.

• International Journal of Aeronautical and Space Sciences
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• 제3권2호
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• pp.59-66
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• 2002

A vertical test stand based on launcher propulsion system was constructed and several tests for the determination of cyclogram were carried out. To make an accurate estimation, static and dynamic pressures were measured and analyzed. Especially, static pressure measurements using fast response sensors without extension tubes were used to determine operation sequence more evidently. The standard operation times of final valves were determined in cold flow tests with an engine head, and fire formation time in combustion chamber was checked in an ignition test with an ignitor only. On the basis of these tests, ignition sequence was established and combustion test cyclogram was finally determined. According to combustion test, test results were well matched with the determined cyclogram within 0.05 sec.

• 전기학회논문지
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• 제64권3호
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• pp.485-491
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• 2015

This paper shows the design improvement and test model of FAU (Frequency Analysis Unit) in PDD (Partial Discharge Diagnosis system) for 800kV GIS (Gas Insulated Switchgear). We found some problems during operation of previous FAU, such as the aging of fiber-optic converter that can cause communication error, the malfunction of signal analysis circuit etc. And then we solved those problems by design improvement and verified the performance through type test. To monitor partial discharge, the performance of UHF sensor is important but the performance of frequency analysis unit is also very important. So we solved communication error, the malfunction of signal analysis circuit and then increased the operation reliability of FAU by improving fiber-optic converter and signal analysis circuit. Accredited testing laboratory carried out the performance verification test according to performance test criteria and procedure of reliability test standards, IEC-60225, 61000 and 60068 etc. We confirmed the test results which correspond with the performance test criteria.

• 항공우주시스템공학회지
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• 제13권3호
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• pp.40-47
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• 2019

본 논문은 무인항공기 체계(UAS; unmanned aerial system)의 비행체 탑재장비 및 지상에서 운용하는 장비의 연동 검증을 위한 체계통합실험실(SIL; system integration laboratory) 및 체계통합시험(SIT; system integration test)의 환경 구축 및 이를 통한 검증방법에 대하여 다룬다. SIL 내 구축된 지상통제체계, 데이터링크체계, 비행체 탑재장비, 임무장비(EO/IR, SAR) 등과 같은 부체계간의 인터페이스 환경 및 모의 비행을 통한 체계 운용로직의 검증방법과 실험실 레벨에서의 검증이 완료된 각 부체계를 실제 시험 환경에서 검증하는 방법에 대해 기술한다.

• 한국항공우주학회지
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• 제38권3호
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• pp.280-287
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• 2010

한국 최초의 위성발사체 나로호(KSLV-I)의 1차 비행시험이 2009년 8월 25일 전라남도 고흥의 나로우주센터에서 실행되었다. 다량의 연료를 싣고 장거리를 비행하는 우주발사체의 특성상 비행중의 비정상 상황에 대한 대비는 매우 중요하며, 본 논문에서는 KSLV-I 발사운영의 안전확보를 위해 진행된 비행안전 업무를 기술하였다. 비행시험 전, 비행시의 비정상 상황으로 인한 위험도 분석을 위한 비행안전 분석이 진행되어 정량적인 위험성을 평가하였으며, 발사시에는 비행안전시스템을 운영하여 위험에 대비하였다. 비행중 추적데이터를 이용한 순간낙하점 계산과 비행상황 감시는 정상적으로 운영되었으며, 비행종단시스템의 동작없이 비행시험을 완료하였다.