• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.835-842
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• 2014

Cutback control in a grid code is one of the functions of a wind power plant (WPP) that is required to support the system protection and frequency stability. When a cutback control command signal is delivered to the WPP from the system operator, the output of a WPP should be decreased to 20% of the rated power within 5 s. In this paper, we propose a dedicated cutback control algorithm of a WPP based on the ratio of the command power to the available power. If a cutback control signal is delivered, the algorithm determines the pitch angle for the cutback control and starts the pitch angle control. The proposed algorithm keeps the rotor speed at the speed before the start of the cutback control to quickly recover the previous output prior to the cutback control. The performance of the algorithm was validated for a 100 MW aggregated WPP based on a permanent magnet synchronous generator under various wind conditions using an EMTP-RV simulator. The results clearly shows that the proposed algorithm not only successfully reduces the output to the command power within 5 s by minimizing the fluctuation of the pitch angle, but also rapidly recovers to the output level before the cutback control.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.3
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• pp.317-327
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• 2021

Low Frequency Active Sonobuoy(hereinafter referred to as LFAS) are being developed in Korea in consideration of compatibility with existing overseas sonobuoys, and a communication device for acoustic signals receiving and operating control of LFAS has been developed. The communication device needs to verify compatibility with the existing Sonobuoy, and for this purpose, the standardized Sonobuoy communication protocol was applied. The communication device is designed/manufactured to transmit the acoustic signal received in real time from the Sonobuoy through VHF band RF communication to the data processing device, and transmit CFS/CSG commands for operation control to the Sonobuoy through UHF band RF communication. In order to verify the manufactured communication device, the communication status and performance were verified by interlocking test through Ultra Electronics' PASS-II equipment and domestically developed electronic device of Sonobuoy. In addition, operability was verified through environmental tests, water tanks, and marine operations. In the future, the communication device of sonobuoy can be used for verification of the Sonobuoy developed in Korea.

• Aerospace Engineering and Technology
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• v.1 no.2
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• pp.45-50
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• 2002

A conceptual design on the link budget of TC&R RF subsystem which transfers command and telemetry data as RF signal between the ground system and the 2005SAT spacecraft is presented in this paper. In order to perform the analysis of the link budget, we divided the analysis process into two processes, i.e., uplink and downlink process. For the uplink the power flux density at the spacecraft and the margin of the command receiver are calculated. In the case of the downlink the downlink EIRP and the margin of C/ No and Eb / No at the ground station are calculated. Through the uplink performance analysis, the power at the command receiver has well efficient margin, and the margin of C/ No and Eb / No is also fully proper for the downlink case.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.616-620
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• 2003

Brake action is important in train operation. In case of diesel motor cas, coachs and wagon, the brake system is only act on the stop of train, but it is emphasis on safety and convenience in urban transit system such as EMU, subwar, AGT, etc. Brake of EMU has two types. one is called service brake that is used at normal operation. The other is called emergency brake. it is used at emergency operation. Service brake bring a EMU to a halt through a blending brake that form electronic brake and frictional brake. Generally EMU compose motor car and trailer car. Blending brake bring a EMU to a halt through a blending brake that form electronic brake of motor car and frictional brake of trailer car. Blending braking technology have different characteristics each nations or manufacturing companies. but deceleration command that is parameter decide blending brake. According to deceleration command, electronic brake and frictional brake are applied differently So braking power is different. electronic brake and frictional brake must be used appropriately as deceleration command. Also braking facilities must be stopped EMU more economically and safely through revision of algorism about blending brake according to output diagram. Thus The purpose of paper is to propose blending braking control way as consideration of braking output diagram used deceleration command that influence blending brake of EMU.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.2
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• pp.219-227
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• 2021

In the present study, the effect of command signals of the flow control valve on performance of underwater discharge systems using a linear pump was investigated numerically. For that, the improved mathematical model was developed. The improvement is to calculate the flow leakage between the water cylinder and the piston. Also the model of the hydraulic cylinder is simplified. To validate the improved model, calculation results were compared with experiment results. The results of the study is as follows: Double ramp command signals of the flow control valve had an advantage over single ramp signals. The parametric study on the effect of double ramp command signals on performance of the system was performed. In case of using double ramp signals, the maximum acceleration of the underwater vehicle was reduced by approximately 50 % compared with using single ramp signals.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1078-1081
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• 2004

A robot manipulator is usually operated in two modes: free motion and constraint motion depending on whether the robot comes into contact with the environment or not. At the moment of contact, impact occurs, and sometimes, it possibly degrade the robot's performance by vibration and at worst, shortens its lifetime. In this article, a new proposed algorithm is described by introducing a command signal modification method on the basis of impedance control and a validity of the proposed algorithm is demonstrated by showing a simulation and an experiment.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.699-701
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• 1987

This paper deals With the EMG signal processing to apply the EMG signal to the Prosthetic arm. The EMG signals are generated by the voluntary contractions of the subject's musculature and is coded into binary words by the pulse width modulation. Command strings or sentences are constructed by concatenating several words, and are syntactically described by a context free grammar in Chomsky normal form and is tried to classify the movement pattern by the CYK algorithm.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.395-397
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• 2001

A new automatic generation control (AGC) signal transmission format will be adopted in the new energy management system (EMS) that KEPCO is planning to install for managing and operating the power system efficiently under the deregulation environment. Therefore, it is necessary for the power plants to make the AGC processing logic fit the new AGC signal flow format. In this work, we compare the new signal transmission scheme with the conventional one in view of its effect to the signal flow in the distributed control systems (DCS) that ale equipped in power plants to handle AGC operation. Then we propose a basic logic configuration for DCS that can be used with the new signal format. In the design of the configuration, some practical issues that should be discussed for the proper operation of the plants are considered.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.35-36
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• 2007

• Journal of the Institute of Convergence Signal Processing
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• v.18 no.2
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• pp.31-36
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• 2017

This study aims to develop an BCI speller utilizing eye-closed and double-blinking EEG based on asynchronous mechanism. The proposed system comprised a signal processing module and a graphical user interface (virtual keyboard-VK) with 26 English characters plus a special symbol. A detected "eye-closed" event induces the "select" command, whereas a "double-blinking" (DB) event functions the "undo" command. A three-class support vector machine (SVM) classifier involving EEG signal analysis of three groups of events ("eye-open"-idle state, "eye-closed", and "double -blinking") is proposed. The results showed that the proposed BCI could achieve an overall accuracy of 92.6% and a spelling rate of 5 letters/min on average. Overall, this study showed an improvement of accuracy and the spelling rate resulting from in the feasibility and reliability of implementing a real-world BCI speller.