• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.4
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• pp.1-9
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• 2003

To reduce the possibility of longitudinal dynamic instability, called "POGO", in the liquid rocket system due to the feedback effect of a main structure and a fuel-feeding system, several different types of PSD(POGO Suppression Device) systems have been studied. In the present study, several different types of PSD were reviewed. Basically, all PSD systems can be categorized into two groups; a passive PSD or an active PSD. We can classify the passive PSD's into more detailed groups according to their compliance methods; localized compliance methods or distributed compliance methods. As a result of our intensive review on various PSD's, the gas-filled accumulator with a level control system is considered to be the most suitable one to suppress the POGO instability without mal-effects to the performance of a fuel-feeding system.ng system.

• 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.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.1
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• pp.98-106
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• 2022

To develop reliable dual pulse rocket motor, vacuum ignition performance at high altitude and design stability for rupture pressure of the Pulse Separation Device(PSD) are required. In this study, rupture pressure analysis method for the membrane type PSD of the dual pulse rocket motor was developed. The PSD rupture pressure formulation was derived from strain-pressure relationships. The PSD vacuum rupture test apparatus and the PSD 1 second vacuum ignition test apparatus were developed, which can simulate the high altitude vacuum environment. Rupture pressure of PSD was analyzed by conducting the PSD vacuum rupture test, and design values of PSD were derived. Finally, vacuum ignition performance and rupture pressure of the designed PSD were validated with PSD 1 second vacuum ignition test.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1408-1415
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• 2007

To operate Platform Screen Door (PSD) automatically, the operational data of PSD and the train must be interfaced properly. PSD and train are operated together by the signaling system in Automatic Train Operation (ATO) signaling system zone where interfaces are provided between PSD and train. However, the additional PSD interface system with train is required in train operating zone without the interface between PSD and train. For the PSD interface, the wireless communication system or the train status (train correct stop status / train door status) detection system has been used. Seoul Metro line No.2. has the PSD wireless communication system using 447MHz band RF. For the safety of PSD operation, it is required to prevent RF interference in the subway environment where many frequencies exist. In this paper, the PSD wireless communication system is developed using 2.4GHz band RF to prevent the interference of the wireless communication and increase the traffic of the PSD interface. Furthermore, the improved system can store, manage and display the PSD and train operational data using Human Machine Interface (HMI) in the train's driver cab.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1144-1147
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• 2017

It was reviewed about the pressure oscillation on the inlet of turbo-pump at the moment of engine startup and shutdown. Specially, This research was performed how much is the effect of PSD(Pogo Suppression Device) about the pressure oscillation on the inlet of turbo-pump at the moment of engine startup and shutdown. For analysis, propellant tank PSD and Engine are modelled with Flowmaster which is the commercial 1D program. As the analysis results, even though the PSD is installed in the pipeline, the pressure drop or rising at the moment of engine startup and shutdown is same compared to the case without PSD. However, it was confirmed that PSD reduces the pressure oscillation of the high frequency band as the original purpose of PSD.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.249-254
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• 2007

A PSD which cooperates with train door provides safety and convenience for passengers. In order to cooperate with train door, the PSD should interface between the PSD control system and the control units of train door. This interface is generally performed in signaling system(ATC/ATO), however, the lines which don't have the interface functionality in the signaling system, it is required to have additional "PSD inter face system" to communicate between train and PSD. In this paper, we propose a safe PSD interface methodology by discussing interlocked control between train door and PSD, recognition of accuracy stop point, troubleshooting logic and log of troubles and driver panel which are adopted in Inchon line1.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1171-1175
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• 2017

Cryogenic helium gas is used as the pressurant for the oxidizer pressurization of DR(Damper Receiver) sphere in the PSD(Pogo Suppression Device) system and liquid oxygen is used as the oxidizer for the propellant in Korea Space Launch Vehicle-II. The helium gas is stored in pressurant cylinders inside the cryogenic liquid oxygen tank and liquid oxygen is stored in the oxidizer tank. In this study, the performance test of PSD liquid oxygen drain valve for KSLV-II was considered.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.257-259
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• 2008

Acceleration time history (ATH) used in the seismic analysis should envelop a target power spectral density (PSD) function in addition to the design response spectrum in order to have sufficient energy at each frequency for the purpose of ensuring adequate load. Even though design regulations require the ATH used in seismic analysis to meet a target PSD function, the reason that ATHs meet to a target PSD function is not described. Thus, artificial ATHs for high PSD function and artificial ATHs for low PSD function are generated. And then elastic and inelastic single-degree-of-freedom (SDOF) systems are loaded with these artificial time histories as the earthquake load. As a result, linear response and inelastic response of SDOF systems are affected by PSD function.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.379-381
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• 2008

본 논문에서는 가정용 비디오 게임에 사용 가능한 고속의 저가형 모션캡쳐, 시스템에 사용되는 전 방향 특성을 갖는 IR 능동 마커의 개발을 목표로 하고 있다. 현재 영화나 게임에서 모션캡쳐를 응용한 시스템 및 컨텐츠들이 많이 선보기고 있으며, 인기를 모으고 있는 추세이다. 이러한 흐름에 맞추어 우리는 이미 저가이면서 속도가 빠른 PSD(Position Sensitive Detector) 센서를 이용만 스테레오 비젼 기반의 PSD 모션캡쳐 시스템(Stereo vision based PSD motion capture system)과 광량 보정 기반의 단일 PSD 모션캡쳐 시스템(Intensity Calibration based single PSD motion capture system) 그리고 일정간격의 두 능동마커 기반의 단안 PSD 모션캡쳐 시스템(Two active markers at fixed distance based single PSD motion capture system)등을 소개한 바 있다. 본 논문에서 제안하는 전방향 특성을 갖는 IR 능동 마커는 일정간격의 두 능동마커 기반의 단안 PSD 모션캡쳐 시스템에 적용하여 보다 정밀한 3차원 좌표 측정을 할 수 있도록 한다. 이를 위해 본 논문에서는 동일 특성을 갖는 마커를 제작하고 평가하여 일정간격의 두 능동마커 기반의 단안 PSD 모션캡쳐 시스템에 적합한 마커의 제작 방법을 제안하였다.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.2
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• pp.32-39
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• 2005

The effectiveness of the pogo suppression device (PSD) on the response of the piping system simulating the fuel (or oxidizer) supply lines of the rocket engines was investigated. The system response defined as the ratio of the flow rate to the pressure in the main tube was obtained for various PSD gas volumes $((0\~2)\times10^{-3}m^3)$ and three different baffle hole diameters (5, 50, 115mm). Existence of a gas volume in the PSD reduced the system resonance frequency. With a larger gas volume, the resonance frequency became lower, but only slightly, while the fluctuations of the main tube pressure and the flow rate damped down considerably. The resonance frequency decreased with the increase of the PSD inlet restriction (or the decrease of the baffle hole diameter), though slightly. However, with a larger inlet restriction, the PSD pressure wave showed a delayed response with the smaller amplitude compared to the pressure variation in the main tube.