• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.7
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• pp.484-491
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• 1987

A sufficent condition for the robust control of the adaptive control system is presented under the convergence of the parameters of the adaptive system. The plant in the adaptive control system is a stable system which includes the unmodelled dynamics and can be approximated by a minimum phase system. It is shown that modified structure which Kosut and Friedlander suggested satisfies the sufficient condition more easily than the original structure without modification. It is also shown by computer simulation that the modified structure and/ or the adaptation method using the normalized input and output data or filtered input and output data can improve the robustness of the adaptive control system.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.484-487
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• 2003

In this paper describes a design of Adaptive high gain observer. The gain of the observer is properly set up using the fuzzy control and adaptive high gain observer that have a superior transient characteristic and is easy to implement compared the existing method is designed. In order to verify the performance of the Adaptive high gain observer which is proposed in this paper, it is compared estimate performance of High-gain Observer and Adaptive High Gain Observer with the computer simulation. Effectiveness of the proposed high gain observer is proved from the simulation to compare the case with a speed sensor to the case with Adaptive high gain observer in the speed control of DC servo motor.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.1
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• pp.83-88
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• 2017

This paper related with the performance evaluation of H-MMA (Hybrid-MMA) which is applying the adaptive modulus and adaptive step size concept to MMA adaptive equalization algorithm in order to reduce the intersymbol interference that is occurred in communication channel for digital code transmission. In the conventional MMA adaptive equalizer, the coefficient is updated by using the equalizer output and possible to compensation of amplitude and phase in 2nd dimensional QAM signal, the equalization performance were degraded due to fixed modulus and step size. For the overcomming the abovemensioned problem, it is possible to improving the equalization performance in the 2nd dimensional QAM signal by applying the adaptive modulus and adaptive step size propotional to equalizer output signal to the conventional MMA algorithm. The computer simulation was performed in the same channel for the compare the performance of MMA and proposed H-MMA which is proposed in this paper. As a result of simulation, the proposed H-MMA has slower convergence time in order to arriving the steady state than MMA. But after the steady state, H-MMA has more superior to the MMA in every performance index and the equalization noise was reduced.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.5
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• pp.107-113
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• 2019

This paper proposes the Hybrid-CRMMA adaptive equalization algorithm that is possible to improves the performance of CR-MMA based on adaptive modulus and adaptive stepsize. The 16-QAM nonconstant modulus signal is reduced to 4-QAM constant modulus signal, and the error signal were obtained based on the fixed statistic modulus of transmitted signal. It is possible to improving the currently MMA adaptive equalization performance. The proposed Hybrid-CRMMA composed of adaptive modulus which is propotional to the power of equalizer output and adaptive stepsize which is function of the nonlinearties of error signal, and its improved equalization performance were confirmed by computer simulation. For this purpose, the output signal constellation, the residual isi and maximum distortion and MSE that is for the convergence characteristics, the SER that is meaning the robustness of external noise of algorithm were used. As a result of computer simulation, it was confirmed that the proposed Hybrid-CRMMA has more superior performance in every index compared to currently CR-MMA.

• Journal of the korean Society of Automotive Engineers
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• v.11 no.1
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• pp.14-19
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• 1989

본 해설에서는 이와같은 SOlution-Adaptive-Grid 방법중 1982년 Blackbill과 Salzman에 의하여 제안된 변분법을 이용한 Solution Adaptive Grid 방법에 대한 기본방정식 그리고 계산방법들을 소개하고자 한다. 이 방법은 논리적 구조에 있어서 명확하고 2차원 3차원 문제에 쉽게 확장시켜 적용할 수 잇기 때문에 많은 연구자들에 의하여 채택되고 있다.

• Journal of the Semiconductor & Display Technology
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• v.3 no.3
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• pp.19-21
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• 2004

This paper presents a 3-dimensional diffusion simulation with adaptive solution strategy. The developed diffusion simulator VLSIDIF-3 was designed to re-refine areas. Refine scheme was calculated by the difference of doping concentration between any of two nodes. Each element is greater than tolerance and redo diffusion process until error is tolerable. Numerical experiment in low doping diffusion problem showed that this adaptive solution strategy is very efficient in both memory and time, and expected this scheme would be more powerful in complex diffusion model.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.4
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• pp.75-80
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• 2021

This paper relates with the Hybrid-DSE-MMA (Hybrid-Dithered Signed Error-MMA) that is possible to improving the equalization performance by using the adaptive modulus and adaptive stepsize in DSE-MMA adaptive equalizer. The DSE-MMA possible to improve the robustness performance to external noise of SE-MMA by using the sign after adding the dither signal for get the error signal in order to update the tap coefficient. But it has a drawback of performance degradation in convergence speed and residual isi by using the fixed modulus and fixed stepsize. In this paper, it was confirmed that this equalization performance degradation was improved by applying the adaptive modulus and stepsize in DSE-MMA propotional to the output power of equalizer by computer simulation. In order to compare the improved equalization performance to currently DSE-MMA, the recovered signal constellation that is the output of the equalizer, residual isi, Maximum Distortion, MSE and the SER were used as a performance index. As a result of computer simulation, the Hybrid-DSE-MMA improve the equalization performance in every index, but gives slower convergence speed compared to DSE-MMA.

• Proceedings of the Korean System Dynamics Society
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• 1999.08a
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• pp.133-157
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• 1999

시스템 다이나믹스는 전통적인 단선론적 인과론을 극복하고 시스템의 동태적 특성을 파악하는데 상당한 공헌을 하였다. 그러나 이러한 시스템의 특성을 방정식에 의존하는 시뮬레이션 기법(Equation-Based Simulation:EBS)을 이용하여 분석하는 경우 방정식으로 묘사하기 어려운 복잡적응시스템(Complex Adaptive System)에서는 한계를 갖고 있다. 따라서 시스템의 동태적 특성을 좀더 정확히 파악을 하기 위해서는 시스템을 구성하는 개체(agent)들의 행동이 시스템 전체에 미치는 영향들을 모형화 함으로써 파악하는 것이 바람직하다고 할 수 있다. 본 연구는 이러한 개체지향 시뮬레이션(Agent-eased Simulation: ABS)의 기법을 복잡성과학의 패러다임을 소개함으로써 그 중요성을 설명하고자 한다. 특히 카오스 이론으로부터 복잡성과학으로의 발전 과정을 개념을 중심으로 논의함으로서 복잡적응시스템의 이해를 돕고자 한다. 또한 ABS가 실제로 전통적인 EBS가 묘사하는 생태계 시스템의 변화를 잘 묘사할 수 있다는 사실을 보여주기 위하여 3개체가 있는 Lotka-Voltera 모형을 Cellular Automata 라는 ABS에 기반 한 시뮬레이션 기법을 활용하여 그 사용가능성을 제시하고자 한다.

• Journal of the Korea Society for Simulation
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• v.14 no.4
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• pp.95-106
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• 2005

Recent advances in wireless sensor networks have led to many routing protocols designed for energy-efficiency in wireless sensor networks. Despite that many routing protocols have been proposed in wireless sensor networks, a single routing protocol cannot be energy-efficient if the environment of the sensor network varies. This paper presents a fuzzy logic based Adaptive Routing (FAR) algorithm that provides energy-efficiency by dynamically changing protocols installed at the sensor nodes. The algorithm changes protocols based on the output of the fuzzy logic which is the fitness level of the protocols for the environment. A simulation is performed to show the usefulness of the proposed algorithm.

• Transactions of The Korea Fluid Power Systems Society
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• v.4 no.1
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• pp.13-17
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• 2007

The brake gain adaptive wheel slip controller for a vehicle is designed in this paper. The brake gain from braking pressure to braking torque defined by friction coefficient, friction area and effective friction radius is estimated by the adaptive law based on the wheel slip dynamics. And the wheel slip controller is designed based on the estimated brake gain. The robustness of the designed controller is analyzed using Lyapunov function and the convergence of brake gain is verified. Proposed wheel slip controller is verified via CarSim simulation with two kinds of desired wheel slip ratio.