• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.11a
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• pp.423-426
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• 2005

In this paper, we proposed a PID tuning algorithm by the fuzzy set theory to improve the performance of the PID controller. The new tuning algorithm for the PID controller has the initial value of parameter Kp, $\tau_{I}$, $\tau_{D}$. by the Ziegler-Nichols formula that uses the ultimate gain and ultimate period from a relay tuning experiment. We will get the error and the error rate of plant output corresponding to the initial value of parameter and fnd the new proportion gain(Kp) and the integral time ($\tau_{I}$) from fuzzy tuner by the error and error rate of plant oueut as a membership function of fuzzy theory. This fuzzy auto tuning algorithm for PID controller considerably reduced the overshoot and rise time as compared to any other PID controller tuning algorithms. And in real parametric uncertainty systems, it constitutes an appreciable improvement of performance. The significant property of this algorithm is shown by simulation

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2584-2586
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• 2000

A drum level control is one of the most important control systems in thermal power plant. The control objective of drum level of boiler in thermal power plant is to maintain drum level at constant set-point regardless of disturbance such as main steam flow. The implemented drum level controller is the cascade PI controller. The important factor in drum level controller is the parameters of two PI controllers. The tuning of PI controller parameter is tedious and time-consuming job. In this paper, the relay feedback Ziegler - Nichols tuning method extended to auto-tune cascade PI drum level controller. Finally, the simulation result using boiler model in Power Plant shows the validity of auto-tuned cascade PI controller.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1862-1863
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• 2006

In this paper, A new tuning method for IMC-PID controller is proposed with the identification using the relay method from closed-loop transfer function. It is considered a second-order plus delay time(SOPDT) model and selected a third-order plus delay time transfer function model as a target function. The filter function is derived from the suitable target function to satisfy the design specifications. A robustness test was done to verify the robust-stability.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.257-262
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• 1994

This paper describes an autotuning fuzzy PID controller for a position control of DC serve motor. Because ZNM(Ziegler-Nichols Method) with relay feedback has the difficulty in re-tuning the PID parameters and adaptive method has complex algorithm, a new method to overcome those problems is required. The proposed scheme determines the initial PID gains by using ZNM with relay feedback, and then re-tunes the optimal PID parameters by using fuzzy expert system whenever control conditions are changed. To show the validity of the proposed method, a position control of DC servo motor is illustrated by computer simulation and is experimented by a designed controller.

• KIEE International Transactions on Power Engineering
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• v.5A no.2
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• pp.125-131
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• 2005

Service restoration is one of the most important missions in distribution system operation. This paper proposes a multi-agent system approach to distribution system restoration. Every relay is developed as an agent by adding its own intelligent, self-tuning and communication ability. The relay agent independently calculates and corrects its restoration index through communication with neighboring agents and its own intelligence. The proposed algorithm is applied to a simple network to demonstrate its soundness and effectiveness.

• Proceedings of the KIEE Conference
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• summer
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• pp.403-405
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• 2004

A service restoration is one of the most important missions in distribution system operation. This paper proposes a multi-agent system approach to distribution system restoration. Every relay is developed as an agent by adding its own intelligent, self-tuning and communication ability. Relay agent calculates and corrects its restoration index by itself through communication with neighboring agents and its own intelligence. The proposed algorithm is applied to a simple network to show how to calculate restoration index. Keywords Multi-Agent System, Service Restoration, Distribution Networks

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.110-113
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• 2002

This paper propose a method for the temperature control using cool-plate in the track equipment. The employed control algorithm is PID control algorithm. The control gains are found using relay auto-tuning algorithm. After that the gains are adjusted manually in trial and error. The control hardware circuit is designed and implemented in the lab. The controlled temperature reached the desired value Within $\pm0.05^{\circ}C$ accuracy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.2
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• pp.247-268
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• 2011

Due to the application-specific nature of wireless sensor networks, the sensitivity to such a requirement as data reporting interval varies according to the type of application. Such considerations require an application-specific, parameter tuning paradigm allowing us to maximize energy conservation prolonging the operational network lifetime. In this paper, we propose a reporting interval adaptive, sensor control platform for energy-saving data gathering in wireless sensor networks. The ultimate goal is to extend the network lifetime by providing sensors with high adaptability to application-dependent or time-varying, reporting interval requirements. The proposed sensor control platform is based upon a two phase clustering (TPC) scheme which constructs two types of links within each cluster - namely, direct link and relay link. The direct links are used for control and time-critical, sensed data forwarding while the relay links are used only for multi-hop data reporting. Sensors opportunistically use the energy-saving relay link depending on the user reporting, interval constraint. We present factors that should be considered in deciding the total number of relay links and how sensors are scheduled for sensed data forwarding within a cluster for a given reporting interval and link quality. Simulation and implementation studies demonstrate that the proposed sensor control platform can help individual sensors save a significant amount of energy in reporting data, particularly in dense sensor networks. Such saving can be realized by the adaptability of the sensor to the reporting interval requirements.

• KIEE International Transactions on Power Engineering
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• v.2A no.3
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• pp.89-94
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• 2002

In this paper, a protection system using a Multi-Agent concept for power distribution networks is proposed. Every digital over current relay(OCR) is developed as an agent by adding its own intelligence, self-tuning and communication ability. The main advantage of the Multi-Agent concept is that a group of agents work together to achieve a global goal which is beyond the ability of each individual agent. In order to cope with frequent changes in the network operation condition and faults, an OCR agent, suggested in this paper, is able to detect a fault or a change in the network and find its optimal parameters for protection in an autonomous manner considering information of the whole network obtained by communication between other agents. Through this kind of coordination and information exchanges, not only a local but also a global protective scheme is completed. Simulations in a simple distribution network show the effectiveness of the suggested protection system.

• The Journal of Society for e-Business Studies
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• v.6 no.2
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• pp.25-38
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• 2001

ATM is the transport method for the broadband integrated services digital networks(B-ISDN). It may replace existing LAN, MAN and WAN technologies such as CSMA/CD, FDDI, Frame relay, X.25, etc. But it is more complicate than existing network technologies. One of the main difficulties in ATM network is performance management. Specifically, the problems are evaluating the performance and tuning the values of the performance parameters, The goal of this paper is to introduce a system architecture designed for ATM network performance management, The major ingredients of the system are generic performance parameters In be measured from ATM network, performance evaluation models and decision criteria concerning the network performance. In this paper, general requirements for performance management application in ATM network are discussed.