• 조명전기설비학회논문지
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• 제27권4호
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• pp.88-95
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• 2013

A new droop control method which can be applied to 3-phase 4-wire uninterruptible power supply is proposed in this paper. The droop control method for parallel operation is very attractive one as UPS parallel operation can be carried out without any data communication devices provided among UPS systems connected, but it reportedly shows a PnP(plug-and-play) problem. A basic reason why a circulating current could flow among parallel-connected UPS systems is clearly investigated as well when droop-controlled-ups systems are operated in the manner of PnP. The proposed algorithm is deduced from the investigated result and is basically structured to keep a balanced frequency and balanced voltage profile against power variation. This paper shows that balanced parallel operation of droop control method can be obtained under unbalanced load as well as balanced load conditions when PnP operation is needed and load change occurs.

• 음성과학
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• 제5권1호
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• pp.105-119
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• 1999

Cleft palate patients have general speech problems with resonance disorders and articulation disorders. The aim of this study is to find the aerodynamic and acoustic characteristics of the nasalization in cleft palate speakers. Thirteen control groups and three cleft palate patients pre- and post operation were selected for these studies. The test words are composed by polysyllabic words: consonants between high vowel /i/ analysis. The cleft palate patients repeated test words pre- and post-operation from one, three and six month periods. The subjects repeated test words on Macquirer and on Nasometer Model 6200-3. The aerodynamic and acoustic results of nasalization show as follows: (1) The nasal rate in overall airflow of aspirated consonant for cleft palate patients shows higher levels than that of the control group. It had decreased since one month after operation. (2) The overall airflow of cleft palate patients is higher than in the control group, however oral air pressure is lower than control group. (3) The nasal airflow and the nasal rate in overall airflow of cleft palate patients has higher than the control group, however its decreased after operation. (4) The nasalance scores of cleft palate patients were 40% higher than that of the control group. The scores did not decrease after operation. The nasalance score of lateral and fricative sounds did not decrease after operation.

• 전기학회논문지
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• 제59권2호
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• pp.338-343
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• 2010

Low cost motor drives are being sought for high volume energy efficient home appliances. Key to the realization of such low cost motor drives is to reduce the power electronic converter in terms of its components, particularly the active devices, finding the motor with least complexity for manufacturing and a controller that could extract the desired performance from the machine and converter combination. These and other factors such as self-starting, speed control over a wide range and most of all the crowning aspect of a four quadrant operation with bare minimum number of controllable switch (or switches) remain as formidable challenges for low cost motor drive realization. In this paper, a four quadrant switched reluctance motor (SRM) drive with only one controllable switch is realized by using a two-phase machine. The theory and operation of the proposed four-quadrant SRM drive with the proposed control algorithm for its realization are described. The motor drive is modeled, simulated and analyzed to verify its feasibility for self-starting, speed control and for four quadrant operation and the simulation results are presented. Experimental results confirm the validity of the proposed control algorithm for four quadrant control of the SRM drive. The focus of the paper is mainly directed toward the control algorithm for realizing the four-quadrant operation of the two-phase SRM drive with a single controllable switch converter.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1149-1154
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• 2007

Fluctuation of control rod was experienced when plant was operating in normal operation mode in WH type NPPs. In order to cope with increased control rod fluctuation, the lead-lag controller setpoint for rod control system was optimized and resulted in increasing the margin of operation and minimizing unnecessary control rod movement. By optimization of the time constant, the margin of operation was increased by $1.5^{\circ}F$ and the control rod movement was not occurred due to mitigation of temperature fluctuation in loop. According to the mitigation of time constant, the margin of operation was increased but safety margin can be affected badly, so that the influences to FSAR design reference was evaluated. As the result of this evaluation, it satisfied the design reference of the existing safety analysis and was applied to NPP after obtaining the approval.

• 동력기계공학회지
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• 제9권4호
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• pp.181-186
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• 2005

Because of advanced control technology, Shop floor control system of various kinds of equipment and machinery need a web based remote monitoring to control process efficiently. This paper presents the development of Operation Control System. Operation Control System(OCS) is based on intelligent web monitoring, so that OCS is improved the working condition for the line of heat treatment process and the product's quality. The developed OCS is consisted of Atmega128(MCU) based on embedded system, running the data logging of the line of heat treatment process. Web monitoring system is based on CS8900 ethernet controller and TCP/IP for remote monitoring responsibility between a server and clients and controlling the progress of entire system. The developed OCS is implemented on the line of heat treatment process and shows the improvement of environment condition, product's quality and efficiency of process line.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1466-1472
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• 2008

To minimize the train operation interruptions and train exchanges, the RF transmission system is proposed. The current control room of the Seoul Metro has information of the train movement through the Total Traffic Control System, but it does not have information of the train itself, rail status, and other facilities' status. When some trouble occurs during train operation, the train crews should report the control room about the trouble and fix it. If the control room has exact information of the trouble, the expert in the control room can help the crews to fix the trouble swiftly and exactly. Since the crews are busy taking care of the trouble, they often miss to report the control room on time. The proposed RF transmission system relays the information of the train to the control room automatically in real time, and makes it possible to provide the passengers good service by reducing the train operation interruptions and train exchanges.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 추계학술대회 논문집
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• pp.255-261
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• 1998

The train automatic operation control system is an on-board train control system that is widely adopted in modern rapid transit systems. The control system consists of TCMS(Train Control and Monitoring System), ATC(Automatic Train Control), ATO(Automatic Train Operation) and TWC(Train to wayside communication) in the train and wayside facilities. The functions of the system is to regulate train riding comfort, to service limited speed and smoothness during start, acceleration, constant speed travel, and fixed point parking under the corresponding commands. The paper describes the simulation model of the train automatic operation control of subway system, configuration of simulator hardware and software and operational algorithms.

• 한국항공우주학회지
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• 제47권3호
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• pp.212-219
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• 2019

군사 작전 환경에서 무인 항공기의 활용도가 확대됨에 따라 효율적인 무인기 제어 방식에 대한 연구가 활발하다. 특히 신속한 임무 처리가 요구되는 군 환경에서 기존의 버튼 방식이 지닌 조작의 불편함을 해소하려는 목적으로 음성인식을 통한 무인기 제어 방식이 시도되고 있으며, 아직 초기연구 수준에 머물러 있다. 본 연구에서는 음성 기반의 무인기 제어를 위해 효율적인 음성인식 시스템 운용 체계를 제안한다. 특히 지상관제 센터에 의한 무인기 제어보다는 유/무인기 협업 환경에서 유인기 조종사가 무인기를 직접 통제하는데 효율적인 음성인식 시스템 운용 방식을 제안하며, 음성인식 실험을 통해 운용 체계의 효율성을 검증한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.318-320
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• 2006

A control valve with deadband characteristics influences on the control dynamics. A control loop with deadband component shows cyclic control results and causes the wears of mechanical parts. A valve on the important process that require nonstop operation cannot be improved during operation. In case of control loops with deadband dynamics, the optimal control parameters based on the performance only are not sure of the good operation in point of protecting the control component. To improve the control performance and control oscillation, the control parameters should be changed to meet both control qualify and protection of control components.

• 해양환경안전학회지
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• 제28권6호
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• pp.937-945
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• 2022

자율운항선박(MASS : Maritime Autonomous Surface Ships)은, 고도의 자율도를 가지고, 계획된 경로를 따라 자율 운항하지만, 필요시 육상원격제어센터(SRCC : Shore Remote Control Center)에서 선박의 운항에 직접 개입할 수 있다. 본 연구에서는 이러한 자율운항선박의 운항을 육상에서 모니터링하고 유사시 원격제어하는 역할을 담당할 육상원격제어사(SRCO : Shore Remote Control Officer)의 교육훈련에 필요한 시뮬레이터 시스템의 운용개념과 이를 가능하게 하기 위한 요구기능에 대해 검토하였다. 육상원격제어 시뮬레이터 시스템은, 다수의 자율운항선박의 운항상황을 모니터링하는 Monitoring Station, 유사시 특정 선박의 운항에 직접 원격개입하는 Control Station의 기능을 모의하도록 하였고, 시뮬레이션 종합통제실, 자율운항선박 운항상황 모의 시뮬레이터, 그리고 주변의 유인선 운항을 모의하기 위한 통항선 시뮬레이터 등으로 구성하였다. 기능적으로는, 육상에서 선박을 직접 제어하기 위하여 원격으로 개입하는 ESRC(Emergency Situation for Remote Control) 상황을 정의하여 이러한 상황을 모의할 수 있도록 하였다.