• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.294-296
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• 2000

Energy recovery in the regenerative region is very important when SRM(Switched Reluctance Motor) is used in traction drive. This is because that to reduce energy loss during mechanical braking and/or to have a high efficiency drive during braking. To control excitation voltage in motor operation and regenerative voltage in the generator operation in the SRM, multi-level voltage control is effective. This paper suggests multi-level inverter which is useful for motoring and regenerative operation in SRM.

• Journal of Families and Better Life
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• v.25 no.5
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• pp.127-141
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• 2007

This study examined the differences of elderly workers' psychological well-being according to gender and explored the variables which account for their psychological well-being. Paid laborers aged 60 or older(eight-five men and nine-eight females) were interviewed. The psychological well-being of male workers was higher than that of the female workers. The control level of activity and family support were the variables that explained the psychological well-being of male paid workers. The higher the control level of activity was, and the more support given from family, the higher the psychological well-being scores they showed. Educational level, demand level of activity, and material reward determined the psychological well-being of female workers. The higher their educational level was, the lower the demand level of activity was, and the fewer rewards they received from paid work, the higher their psychological well-being was.

• Journal of Korean Biological Nursing Science
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• v.14 no.2
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• pp.103-111
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• 2012

Purpose: The purpose of this study was to identify the effect of self-efficacy promotion of the smoking cessation program on the amount of smoking, carbon monoxide level, urine cotinine level and the smoking cessation self-efficacy of adolescent smokers. Methods: The subjects composed of 24 for the experimental group and 28 for the control group who were smoking adolescents at the Middle School in G city. The data collection was done from October 13 to November 18, 2010. A nonequivalent control group pretest-posttest design was used. This program was composed on the basis of Shin (1997)'s Self-Efficacy Promoting Program. The self-efficacy promotion smoking cessation program was conducted for 2 hours per week, and lasted for 6 weeks on the experimental group. The control group had a general smoking program. Data was analyzed using SPSS/WIN 14.0 program. T-test was used to analyze outcome measures. Results: The amount of smoking, CO level, urine cotinine level, and self efficacy level of the experimental group was significantly improved more than that of the control group after intervention. Conclusion: Therefore, self-efficacy promotion smoking cessation program for adolescent smokers can be recommended for smoking cessation of adolescents.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1821-1834
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• 2017

Medium voltage control applications due to obtain better output voltage and reduced electro-magnetic interference multi level inverter is used. In closed loop control with inverter, the PI controller does not operate satisfactorily when the operating point changes. This paper presents the performance of Co-Efficient diagram PI controller based indirect vector controlled induction motor drive fed from three-level inverter under different operating conditions (dynamic and steady state). The proposed Co-Efficient diagram PI controller based three level inverter significantly reduces the torque ripple compared to that of conventional PI controller. The performance of the indirect vector controlled induction motor drive has been simulated at different operating conditions. For three-level inverter control, a simplified space vector modulation technique is implemented, which reduces the coordinate transformations complications in the algorithms. The performance parameters, torque ripple contents and THD of induction motor drive with three-level inverter is compared under different operating conditions using CDM-PI and conventional PI controllers.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.641-643
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• 2004

Liquid Zone Control System controls the power of heavy water reactor. Changing the level of each zone compartment regulates one local zone power of 14 zone powers, iud the level is limited less than 90% by the control algorithm to prevent the flood. In recent years, the level and the power was controlled oscillatory in the upper zones. To find out the condition of cycling, the zone control system was modelled with the linear difference equations and identified using parameter estimation. The pole-zero plot showed that the major pole was near the stability boundary, and the system had oscillatory characteristics in nature.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.3
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• pp.363-369
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• 1999

In this paper, we design the robust $H_{\infty}$ controller for water level control of steam generator using a mixed $H_{\infty}$ optimization with model-matching method. Firstly we choose the desired model which has good disturbance rejection performance. Secondly we design a stabilizing controller to keep the model-matching error small and also provide sufficiently large stability margin against additive perturbations of the nominal plant. Simulation results show that proposed robust $H_{\infty}$ controller at specific power operation has satisfactory performances against the variations of load power, steam flow rate, primary circuit coolant temperature, and feedwater temperature. It can be also observed that the proposed robust $H_{\infty}$ controller exhibits better robust stability than conventional PI controller.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.5
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• pp.793-800
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• 2004

The purpose of this study is to develope a servo system with faster and more accurate response. This paper describes a method of approximate reasoning for fuzzy control of servo system based on the decomposition of $\alpha$-level fuzzy sets. We propose that fuzzy logic algorithm is a body from fuzzy inference to defuzzificaion cases where the output variable u directly is generated PWM The effectiveness for robust and faster response of the fuzzy control scheme are verified for a variable parameter by comparison with a PID control and fuzzy control A position control of DC servo system with a fuzzy logic controller is demonstrated successfully.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.8
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• pp.376-383
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• 2001

Factors leading to poor control of the steam generator in a nuclear power plant are nonminimum phase characteristics, unreliable of flow measurements and nonlinear characteristics, which increase more at low power(below 20%) operation. And the study of problems for water level control in the steam generator is that design water level controller only power renge, not entire. This paper introduces a model predictive control(MPC) algorithm for solving poor control factors and quadratic programming(QP) for solving input constraints. Also presents the design method of stable model predictive controller in the entire power range. The simulation results show the efficiency of proposed MPC controller by comparing with PI controller, and effect of the design parameters.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.1
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• pp.61-68
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• 2010

This paper proposes networked swarm robotic systems with group based control scheme using spring damper impendence feature. The proposed algorithm is applied to keep system arrangement in unexpected situations based on the spring-damper impedance and fuzzy logic. Using the proposed scheme, each robot overcome collision problems efficiently. The structure of UBSR (UMPC Based Swarm Robot) system consists of user level, cognitive level, and executive level. This structure is designed to easily meet the different configuration requirements for other levels. Simulation results show an availability of the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.82.3-82
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• 2001

This work presents a design technique for the implementation of the liquid level control system by based on the use of a single-chip microcontroller. The proposed model system offers the following attractive features : (1) application of the pressure transducer for sensing the height of liquid in tank (2) using the obtained liquid level for defining on-off condition of the water pump (3) the liquid values were controlled by using stepping motors for controlling of 57 points (4) can set up by using manual control or automatic control (5) can monitor and display the process status either on microcontroller-based control board or on the computer via RS232 serial-port. Experimental results have been employed to show the effectiveness ...