• Journal of Aerospace System Engineering
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• v.6 no.3
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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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• 2010.11a
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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.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.3
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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.

• Proceedings of the KSR Conference
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• 2003.10c
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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.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.4
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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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• v.3 no.2
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.3
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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.

• Journal of Aerospace System Engineering
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• v.13 no.3
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• pp.40-47
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• 2019

This paper proposes the environment construction and test method of system integration laboratory (SIL) and system integration test (SIT) for verification of interface between onboard equipment and ground control equipment of unmanned aerial systems (UAS). This research also describes the interface environment between subsystems built in SIL and verification methods for the systems' operation logic through simulated flights. Similarly, the paper handles the ground integration test process of UAS in the real testing environments.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.3
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• pp.280-287
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• 2010

The first Korean satellite launch vehicle, KSLV-I(Korea Space Launch Vehicle-I), was launched for its first flight test on Aug. 25, 2009 from Naro Space Center located in south Jolla province. Because launch vehicles usually fly long range with large amount of propellants aboard, preparation of countermeasures against potential malfunctions during flight is essential in launch operation. In this paper, the flight safety operation, prepared to guarantee flight safety during launch operation of KSLV-I, is presented. Prior to flight test, flight safety analysis is performed to estimate associated risk levels quantitatively, and during flight, flight safety systems are operated to cope with any risky situations. Real-time flight monitoring including computation of instantaneous impact point using tracking data is executed normally and the flight test is completed without activation of flight termination system.