• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.6
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• pp.128-135
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• 1996

In this paper, a digital signal processing method of AFC (automatic frequency control) is proposed for a home use VCR system. The proposed method has the ability of frequency tracking of a wide range. Implemented with digital circuits, the system is to be used in a digital video system and saves the cost of a hardware compared with a conventional analog automatic frequency control method using several PLL's in case of making home use VCR systems compatible with several TV systems.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.1
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• pp.113-118
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• 2006

This paper presents a new linear-matrix-inequality-based intelligent digital redesign (LMI-based IDR) technique to match the states of the analog and the digital T-S fuzzy control systems at the intersampling instants as well as the sampling ones. The main features of the proposed technique are: 1) the affine control scheme is employed to increase the degree of freedom; 2) the fuzzy-model-based periodic control is employed, and the control input is changed n times during one sampling period; 3) The proposed IDR technique is based on the approximately discretized version of the T-S fuzzy system, but its discretization error vanishes as n approaches the infinity. 4) some sufficient conditions involved in the state matching and the stability of the closed-loop discrete-time system can be formulated in the LMIs format.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.04a
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• pp.378-381
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• 2005

This paper presents a new linear-matrix-inequality-based intelligent digital redesign (LMI-based IDR) technique to match the states of the analog and the digital T-S fuzzy control systems at the intersampling instants as well as the sampling ones. The main features of the proposed technique are: 1) the fuzzy-model-based periodic control is employed, and the control input is changed n times during one sampling period; 2) The proposed IDR technique is based on the approximately discretized version of the T-S fuzzy system, but its discretization error vanishes as n approaches the infinity. 3) some sufficient conditions involved in the state matching and the stability of the closed-loop discrete-time system can be formulated in the LMIs format.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.243-249
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• 2003

With distribution industrial control system, the use of tow cost to achieve a highly reliable and safe system in real time distributed embedded application is proposed. This developed intelligent node is based on two microcontrollers, one for the execution of the application code, also as master controller for ensuring the real time control & the logic operation with PLD and other for communication task and the easy control execution, i.e., I/O digital input, digital output and interrupting. This paper also presents where the case NCS(Networked control system) with LonTalk protocol is applied for the filtration process control system of a small water treatment plant.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.10
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• pp.637-645
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• 2000

This study was represented the improvement of the flexible position control for linear motion of hybrid type linear pulse motor(HLPM). The driving method used a minute 125 microstep drive instead of full step drive method. The digital control method was applied to the PI control for more stable position control, at this time the PI control parameters have gained by a Ziegler-Nichols turning method. The loop transfer function of control system was combined with both motor transfer function and digital PI control equation. Such, the proper for digital PI control system is verified to through the simulation and experimental result of the stability step response and bode plot with proper gain and phase margin.

• 전기의세계
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• v.30 no.8
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• pp.509-516
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• 1981

The optimal control theory is applied to the design of a digital control system for a nuclear reactor. A linear dynamic model obtained at 85% of rated power and a quadratic performance index are used. A minimal order observer used in cascade with the feedback controller is suggested as a state estimator. The total reactor power control is studied in the range of 80% to 100% of rated power, with the steady state and load-following control. The control algorithm considered is suitable for implementation in direct digital control.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.8
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• pp.112-119
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• 1996

Among the various type of accelerometer, the servo rebalancing type accelermoter can be suitable for Inertial Navigation System, because of its high sensitivity and good response in low frequency. In this paper, we proposed a new technology to control inductive tuype accelerometer utilizing digital PWM method. The new developed digital PWM control has special design scheme for transmitting measurement value to outer device in its servo ollp. So it has no quantized error of transforming outputs of sensors to digital domain. The quantized error may make serious problem in INS system, because outputs of sensor are integrated once or twice by digital computer and it happens every sensor reading times. Therefore, in order to get the accurate information such as displacement, it is necessary to measure accurately the input current. In addition, Digital Signal Processing needs digital data transmission, digital PWM method is adaptive for this purpose. We realized a practical circuit for digital PWM control, analyzed the stability of the circuit, and designed the controller etc. In this study, we solved many practical problem for this application, and got out good results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.5
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• pp.593-602
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• 2004

We have developed a digital control rod control system not only to improve its performance but also to improve its reliability and speed of response so that it can replace the old fashioned analog system. However, a new developed digital control system should be tested to prove the validity by using any prototype or mock-up before application. The reliability prediction and the reliability block diagram analysis methods were adopted to verify the reliability of the developed hardware. For the case of software, especially fur a new developed control algorithm it has been tested to prove performances and validation by using a dynamic simulator and mock-up of control rod drive mechanism altogether. Here we want to present some key factors regarding to the new developed digital system with some verification procedures.

• Journal of Advanced Marine Engineering and Technology
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• v.16 no.4
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• pp.50-59
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• 1992

The paper presents a digital speed control approach of induction motor systems by using a digital servo control method and a well-known second order differential equation as model. The basic concept of using the modeling equation stated in the above is induced from the control theory stand point such that we can describe usually the motor system connected by inverter, generator and load etc, just as a mechanical system to be controlled. The concept does not demand us the complicated vector-based modeling equation adopted in the traditional methods for the speed control of induction motor. Futhermore, the proposed speed control system can be treated as a single input and single output system. The effectiveness of the servo control system obtained by the above-mentioned design concept is illustrated by the experimental results in the presence of both step reference changes and load variations. It is observed from the experimental results that the steady state-error of the experimental set up becomes zero after some regulation time and the induction motor system is robust in spite of reference signal changes and load variations.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.151-155
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• 2004

In this paper, an automatic lighting control system is developed using micom. The developed system consists of digital lighting control system, analog lighting control system and simulator. In the developed system, ATMega128 is used as the main controller. The developed digital lighting control system consist of eight parts and the developed analog lighting control system consist of six parts respectively. Additional, the developed simulator consist of analog and digital simulation using graphic user interface.