• 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.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.332-336
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• 1989

This paper describes the nonlinear analysis and effectual operation methods of thermal power plant turbine control system. When the turbine control governor system has dead-zone characteristic, the effectual frequency development control is difficult, because turbine output does not correspond to frequency deviation in dead-zone. Therefore to obtain effectual correspondance, the turbine dead-zone characteristic must be analyzed by proper method. This paper proposes this nonlinear analysis and effectual plant operating load.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.8
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• pp.729-735
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• 2012

A LQG/LTR(linear quadratic Gaussian/loop transfer recovery) controller with an integrator is designed to control the electro-hydraulic positioning system. Without considering the nonlinearity in the dead-zone, computer simulations are performed and show good performances and tracking abilities with the feedback controller based on the linear system model. However, the performance of the closed loop hydraulic positioning system shows big steady-state error in real system because of the dead-zone. In this paper, the feedback controller with a nonlinear compensator is introduced to overcome the dead-zone phenomenon in hydraulic systems. The inverse dead-zone as a nonlinear compensator is used to cancel out the dead-zone phenomenon. Experimental tests are performed to verify the performance of the controller.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.614-619
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• 2012

A LQG/LTR(Linear Quadratic Gaussian/Loop Transfer Recovery) controller with an integrator is designed to control the electro-hydraulic positioning system. Without considering the nonlinearity in the dead-zone, computer simulations are performed and show good performances and tracking abilities with the feedback controller based on the linear system model. However, the performance of the closed loop hydraulic positioning system shows big steady-state error in real system because of the dead-zone. In this paper, the feedback controller with a nonlinear compensator is introduced to overcome the dead-zone phenomenon in hydraulic systems. The inverse dead-zone as a nonlinear compensator is used to cancel out the dead-zone phenomenon. Experimental tests are performed to verify the performance of the controller.

• Journal of radiological science and technology
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• v.21 no.2
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• pp.57-63
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• 1998

AEC was designed to assist in the production of radiographs of equal density and to aid in the production f consistently high quality radiographs. Many improvements have been made in the AEC and these have helped to increase it's acceptance. Newer system (Falling load) control kVp and mA as well as exposure time. Authors have had experiments about the characteristics of AEC by Zone System. Zone System is the method to detection of photographic image qualify by control the photo print from Fred Archer and Ansel Adams. With the Zone System theory the experiments of density control, characteristics of phantom thickness and reproducibility of occupation rate of contrast media could make quality control of X-ray photography effectively in falling load system.

• Journal of Korean Society of Transportation
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• v.29 no.2
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• pp.111-121
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• 2011

This paper discusses a method for optimizing the semi-actuated traffic signal control system by adjusting the initial interval according to the number of vehicles waiting for the green light in the actuated phase. We also present a Left-Turn actuated traffic signal control strategy that examines the vehicular noise in the detection area and determines the phase extension and the gap-out. In order to detect the vehicles in real-time, an image detector's Video Image Tracking technology was adopted. A 'Zone in Zone'method was implemented, and the image detection area is segmented into three zones: 1) Zone1 for verifying a vehicles obligatory presence, 2) Zone2 for counting the standby vehicles, and 3) Zone3 for examining the number of vehicles that have passed. The on-site assessment of the Left Turn Actuated Control is carried out using CORSIM, and the results show that the Control Delay decreased by 23.10%, 15.06%, and 4.34% compared to the delays resulted from pre-timed control, semi-actuated control-1 and semi-actuated control-2 traffic signal control systems respectively. The Queue Time also decreased by 36.24%, 20.10% and the Total Time by 14.36%, 7.02% for the same scenario. Which clearly demonstrates the operational efficiency. A sensitivity analysis reveals that the improvement from the propose traffic control strategy tends to increase as the through traffic volume reaches a saturated condition and the left-turn traffic volume decreases.

• The korean journal of orthodontics
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• v.22 no.2 s.37
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• pp.427-447
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• 1992

The purpose of this study was to evaluate the effect of the lateral displacement on the mandibular condylar growth in the rabbit. The experimental animals were twenty White NewZealand rabbits of 4-week old. Ten of them was used as control group, and experimental animal was composed of remaining ten. Laterodeviation appliance was made of cast base metal and appliance was cemented with resin in permanent fashion. Experimental group were sacrificed at 1, 2, 4, 6, 8 weeks form beginning of the experiment. Both of temporomandibular joint were prepared for histologic study. The conclusions are: 1. In control group, there was slight increase of proliferative zone and hypertrophic zone at 2-week control animal and slight reduction at 4-week. 6-week and 8-week control animal were similiar to 1-week control animal. 2. In right mandibular condyle of experimental group, 2-week experimental animal showed marked increase of proliferative zone and hypertrophic zone at posterior surface of condylar head. In 8-week experimental animal marked increase at anterior surface of anticular surface is observed. 3. In left mandibular condyle of experimental group, proliferative zone and hypertrophic zone were reduced at 1-week experimental animal and slight increase at 2-week. Proliferative zone and hypertrophic zone were reduced at 4-week experimental animal and were slightly increased at 6 week. 4. After 8 weeks, right and left condyle were not different in experimental group. The condylar cartilage was stabilized 8 weeks after the experiment. No marked traumatic change was seen, but minute focal bleeding was seen at articular cavity in 1-week, 2-week and 4-week experimental animal. 6-week and 8-week experimental animal did not show bleeding tendency in articular cavity.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.8
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• pp.1140-1145
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• 2014

Tunnel lighting is composed of entrance zone, interior zone and exit zone by KS C 3703. We have to consider adaptation at entrance zone and exit zone lighting to prevent deteriorate visibility like black hole and white hole phenomenon. So External luminance, vehicle velocity and traffic volume should be considered in threshold zone lighting and vehicle speed and traffic volume should be considered in interior zone lighting. But existing tunnel lighting system is not good at visibility and economic because that is only controled by external luminance. So in this paper, We improve visibility and economic of tunnel lighting system using fuzzy reasoning according to external luminance, vehicle velocity, traffic volume.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.675-677
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• 2004

This paper presents a nonlinear controller design for optical disk drive systems to improve anti-shock performance. The nonlinear anti-shock controller is added parallel to the original linear servo control loop. In the previous work, dead-zone nonlinear element is used for nonlinear controller and PID control method is used for linear controller. Although this strategy improves anti-shock performance, it has a narrow stability bound. In this paper, we propose dead-zone with saturation nonlinear element for the nonlinear controller. Since this nonlinear element improves stability margin, we can use higher gain of dead-zone than the controller with dead-zone only. In the linear controller design, we show that lead-lag control has improved stability margin over PID control. Numerical simulation results show that the proposed method can get better performance to the external shock than previously proposed method.

• Proceedings of the Safety Management and Science Conference
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• 2010.04a
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• pp.259-265
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• 2010

The research discusses the implementation of control charts tools of MINITAB which are classified according to the type of data and the existence of subgrouping, weight and multivariate covariance. The paper presents the three integrated models by the use of zone, multivariate $T^2$-GV(Generalized Variance) and ARIMA(Autoregressive Integrated Moving Average).