• International Journal of Aerospace System Engineering
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• v.4 no.2
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• pp.5-9
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• 2017

In a pressurized fuel supply system of aircraft, a flow passage opening device is required to keep fuel continuously transferred from one tank to the other. The device utilizes balancing weights in order to follow up an acceleration at special conditions such as negative g. It is very difficult to test the device in a real high-speed and high-altitude test since severe test conditions and expensive supports are needed. Therefore, this paper deals with performance analysis of a flow passage opening device through low speed aircraft captive flight tests (CFT) including roll and negative-g maneuvers. It is shown that balancing weights in the device can open the passage in accordance with fuel position.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.10
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• pp.801-807
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• 2020

Opening characteristics of a main oxidizer shut-off valve at different valve inlet pressures have been experimentally investigated. The pilot pressure at the moment of the valve opening increases linearly with increasing the valve inlet pressure and the increased pilot pressure reduces the valve travel time. As the pilot pressure increases at the moment of valve opening, the time to start opening the valve is delayed resulting in increasing the valve opening time. With the increment of the valve inlet pressure, the valve opening time is mainly determined by the time required for the pilot pressure to start opening the valve. Therefore the design of a pilot gas supply system can readily control the valve inlet pressure at the valve opening as well as the amount of oxidizer supplied to a combustion chamber during the engine startup.

• Journal of the Korean Solar Energy Society
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• v.32 no.4
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• pp.51-58
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• 2012

This study aims to analyze characteristics of Cell surface temperature and generated power performance for improving PV(Photovoltaic) system condition according to the cell opening ratio of transparent crystal PV system at Spandrel of curtain-wall. For this purpose, alternatives were classified for eight different cases that opening ratio of transparent crystal PV system varied from 0% to 70%, which was used by simulation tool, EnergyPlus. As results, it turned out that increasing opening ratio of transparent crystal PV system led higher PV surface temperature, back-sheet type was thus the most advantageous for decreasing surface temperature, annual generating efficiency, and annual accumulated generating power. Consequently, blocking off air space from outside insolation can advantageously keep to be better condition for generated power performance.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.2
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• pp.157-163
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• 2004

Optimal transducer positions are important as much as the control algorithms and hardware performance in the active noise control system. This study is similar to the past researches on the optimal transducer locations but with a far field noise source having a plane wave characteristic and the noise coming through an opening such as a window in an enclosure. Optimization techniques are used to find sets of optimal loudspeaker positions from a larger possible loudspeaker positions. Loudspeakers are placed on the surface of opening at the wall and inside of the enclosure. Using the measured acoustic transfer impedances and numerical simulations with the optimization technique, optimal positions are identified and compared. When a small number of loudspeakers are used. loudspeaker positions on the opening near the center seems to be the best place, but when a larger number of loudspeakers are used it was difficult to find simple patterns in the optimal positions. With the optimally positioned loudspeakers, optimal microphone positions are also studied.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.788-791
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• 2003

Optimal loudspeaker positions are important as much as the control algorithms and hardware performance in the active noise control system. This study is similar to the past researches on the optimal transducer locations but with a far field noise source having a plane wave characteristic and the noise coming through an opening such as a window in the enclosure. An optimization technique called simulated annealing algorithm is used to find a set of optimal loudspeaker positions from a larger possible loudspeaker positions. Loudspeakers are placed on the surface of opening at the wail. Using the measured acoustic transfer impedances and numerical simulations with the optimization technique, optimal positions we identified and compared. When a small number of loudspeakers are used, loudspeaker positions on the opening near the center seems to be the best place, but when a larger number of loudspeakers are used it was difficult to find simple patterns Un the optimal positions.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.447-452
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• 2001

An automated system is developed to perform fatigue crack growth tests under constant effective stress intensity factor range ${\Delta}K_{eff}$. In the system, crack length and crack opening load are measured in real-time by using the unloading elastic compliance method. The system consists of two personal computers, an analogue electrical subtraction circuit, a stepping motor, a stepping motor driver, a PIO board, and the application software used to integrate the whole system. The performance of the developed system was tested and discussed performing constant ${\Delta}K_{eff}$ crack growth tests on a CT specimen of 7075-T6 aluminum alloy. The performance of the system is found to be strongly dependent on the accuracy of measurements of crack opening load. Besides constant ${\Delta}K_{eff}$ testing, the system is expected to be successfully applied for automation of various fatigue tests.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.476-481
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• 2001

In a vacuum circuit breaker mechanism, a spring-actuated linkage system is used to satisfy the desired opening and closing characteristics of electric contacts. Because the opening dynamics of electric contacts is determined by such a linkage system, the stiffness, free length and attachment points of a spring become the important design parameters. In this paper, based on the energy conservation that the total system energy is constant throughout the operating range of a mechanism, a systematic design procedure of determining the spring design parameters is presented. The proposed procedure is applied to the design of an opening spring for satisfying the specified opening characteristics.

• Journal of Auto-vehicle Safety Association
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• v.5 no.2
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• pp.51-56
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• 2013

In vehicle's door wiring harness (W/H) system is more toward to arrange a passenger compartment than a hinge and a weatherstrip. An opening/closing member of a vehicle is attached to a vehicle by a hinge in a manner enabling easy opening and closing of the opening/closing member. Such members include doors, such as side-doors and rear doors, and other opening/closing members, such as trunk lids. This article gives some insight into the dimensioning process, with special focus on large deflection analysis of wiring harness(W/H) in vehicle's door structures for durability problem. The Finite elements analysis for door wiring harness(W/H) is used for residual stresses and dimensional stability with bending flexible. Durability test data for slam test specimens were compared with the numerical predicted fatigue life for verification. The final testing of the component combines the effects of these microstructural features with the complex stress state arising from the combined service loading and residual stresses.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1287-1294
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• 2021

This paper is a study on the implementation of a sensor-based smart compression system for improving home and street environments. Since modernization, the amount of garbage has been increasing every year, and this has seriously adversely affected not only people but also ecosystems such as marine pollution and soil pollution. In particular, in large cities with large floating populations, garbage is dumped on the streets without proper measures to deal with the amount of waste generated. In order to improve this problem, this paper intends to implement a system with automatic compression and opening/closing functions using sensors. This system is designed to activate automatic opening/closing function through an infrared sensor, and automatically opening and closing when the inclination is changed using an impact sensor. In addition, by installing a distance sensor, the amount of internal waste can be easily monitored from the outside, and a manual compression switch and a manual opening/closing switch is separately designed to enable opening and closing and compression as needed to increase the effectiveness.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.559-571
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• 2008

Platform Screen Door(PSD) has been installed and operated at seoul subway line $1\sim4$ in the manual train operation mode(ATS/ATC) by SeoulMetro since 2005. SeoulMetro uses the wireless (RF) communication system and the train door detection system for the link between the train and PSD doors opening/closing motion in the manual train operation mode. For the convenience and safety of passengers, the train doors and the PSD doors opening/closing shall be synchronized as much as possible. In ATO(Automatic Train Operation) mode which provides the interface between train control system and PSD system, ATO signaling system makes the train doors and PSD doors open/close command signals systematically, so PSD doors can be opened/closed almost simultaneously with the train doors. But, in the manual train control(ATS/ATC) mode, PSD system needs to detect the train doors open/close operation and make PSD open/close command signals to actuate PSD doors. These PSD open/close commanding process cause time delay of PSD doors opening/closing motion in response to the train doors opening/closing motion. Sometimes the response delay time can be over 1 second, which is not proper to operate PSD, and need to be reduced This paper presents the reduction method of the PSD response delay time to improve the convenience and safety of passengers.