• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.563-568
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• 2010

Turbopump-gas generator open-loop coupled tests are performed during the development of a 30tonf-LOx/Kerosene rocket engine. In the turbopump-gas generator open-loop tests, the propellants to gas generator are supplied from the outlets of turbopump, while the gas exhausted from the gas generator is vented out to the atmosphere, instead of being used to turbine driving. This paper presents the objectives, procedure, and results of the open-loop coupled test, in addition to a schematic representation of the test apparatus and the operating conditions for the test facility system and control system. The results of turbopump-gas generator open-loop coupled test confirm chill-down procedure, startup characteristics, nominal operability and smooth shutdown of the open-loop coupled Test Plant in test conditions simulating engine system operation environment.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.69-77
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• 1993

Adaptive Control is applied to regulate cutting force in turning operation under varying cutting conditions. Regulation is achieved primarily by adjusting feedrate. Such control leads to better machine utilization and increased tool life. The modeling of adaptive control system in turning operation is presented. The experimental results show that the adaptive PI controller is stable and performs more effective force control over wide range of cutting conditions as compared with the fixed gain PI controller.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.4
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• pp.560-565
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• 2020

Korea's seaweed is using a method that is not suitable for the automated process and quality are significantly lower than the export volume of 20,000 tons or more. Therefore, in this paper, we improved the existing dry steaming weight control device and electronicized the remote control system and the existing dry steaming weight control device. This is implemented with precise and detailed device, unlike the dry seaweed weight control method using the conventional valve which depends on the user's feeling and experience. Also, because it is a remote control system, it can help to produce seaweed safely even if you don't climb on the machine. The Seaweed weight control device implemented is expected to contribute greatly to the automation process and industrial growth of the steeply growing dry laver production and export industry.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1A
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• pp.27-33
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• 2009

This paper proposes transmit power control techniques with fading channel prediction scheme based on recurrent neural network for high-speed mobile communication systems. The operation result of recurrent neural network which is derived interpretively solves complexity problems of neural network circuit, and channel gain of multiple transmit antenna is derived with maximum ratio combining(MRC) by using the operation result, and this channel gain control transmit power of each antenna. simulation results show that proposed method has a outstanding performance compared to method that is not to be controlled power based on channel prediction. Most of legacy studies are for robust receive technique of fading signals or channel prediction of fading signals limited low-speed mobility, but in open loop Power control, proposed channel prediction method decrease system complexity with removal of fading effect in transmitter.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.90-97
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• 1991

A stepping motor can be driven with open-loop or closed-loop control. The major disadvantage of open-loop control is that it is subjected to resonance and instability in certain speed range, and that there is no way to check stalling or error in position. In this paper, a closed-loop control system consisting of a microcomputer, a hybrid stepping motor, a drive, a lead screw, and an encoder which is used as a position sensor is developed. A control program is programmed in assembly language for real time control and the versatile interface adapter(VIA) is used as the interface with the microcomputer. The experimental results of the stepping motor were eliminated on all kinds of inertia load, and maximum start stop pulse rate and maximum slewing pulse rate were also increased about twice respectively.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.6
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• pp.94-101
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• 1994

About vibration model of Six-degrees-of-freedom(DOF), in mass load, examined results for knowing dynamic interference and response variation is as follows; In case of putting mass load upon the object, experimented results on two-degrees-of-freedom of the translation-1 direction and the rotation-1 direction at open-loop-control system, about 0.19 arcsed in input of the translation-$0.1{\mu}m$ and $0.022{\mu}m$ on input of the rotation-0.5 arcsec, the justicse of motion equation is acknowledged as confirming the appearance of the interference-$0.022{\mu}m$. In establishing calculation of transformation matrix by using analogue circuit, as simulating results that used incomplete differentiation, interference is $1.7{\times}10^{-3}$ arcsec on input of the translation-$0.1{\mu}m$ and $1.4{\times}10^{4}{\mu}m$ on input of the rotation-0.5 arcsec in open-loop-control system. Also it is $4.2{\times}10^{-4}$ arcsec on input of the translation-$0.1{\mu}m$ and $5.6{\times}10^{-5}{\mu}m$ on input of the rotation-0.5 arcesc in closed-loop-control system. As closed-loop-control system is better than open-loop-control system, equivalent accordance is confirmed on original response. Finally, fundamental validity of this theory is acknowledged.