• 한국보육지원학회지
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• 제16권1호
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• pp.75-98
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• 2020

Objective: This study aimed to examine the influences of household chaos on self-control of young children and to investigate whether teachers' limit-setting styles had moderating effects. Methods: The participants were 184 children (83 boys and 101 girls), at age 3 -5, their mothers and teachers working at daycare centers located in Seoul and Gyeonggi-do. The data were analyzed by descriptive statistics, Pearson's correlation, and hierarchical regression. Moderating effects were examined using the Mplus8.0 program. Results: The results indicated that household chaos as well as teacher's permissive and logical limit-setting styles had significant effects on self-control of preschoolers. The lower the level of household chaos was, the higher the level of self-control of preschoolers was. The level of self-control was more likely to be high when teachers used logical limit-setting with detailed explanation to children whereas it was lower when they used more permissive limit-setting. In addition, teachers' logical limit-setting moderated the relation between household chaos and self-control of preschoolers. That is, the effects of household chaos on preschoolers' self-control were mitigated when the level of logical limit-setting was high compared to when it was low. Conclusion/Implications: The results suggested that both household chaos and teachers' limit-setting styles play important roles in increasing self-control of preschoolers.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.93.1-93
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• 2002

In this paper, an efficient robust control method for chaotic system introducing the concept, the edge of chaos (:boundary status between chaos and non-chaos), is proposed. To realize this concept, we introduce an extended performance index which consists of two parts. One is for achievement of the system's objects, another is for keeping the system edge of chaos. Parameters of the neural network controller are adjusted to minimize the value of the extended performance index and achieve the above two objects using Random...

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1843-1850
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• 2015

Controlling nonlinear systems with linear feedback control methods can lead to chaotic behaviors. Order increase in system dynamics due to integral control and control parameter variations in PID controlled nonlinear systems are studied for possible chaos regions in the closed-loop system dynamics. The Lur’e form of the feedback systems are analyzed with Routh’s stability criterion and describing function analysis for chaos prediction. Several novel chaotic systems are generated from second-order nonlinear systems including the simplest continuous-time chaotic system. Analytical and numerical results are provided to verify the existence of the chaotic dynamics.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제3권1호
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• pp.1-6
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• 2003

The Delayed Feedback Control method (DFC) proposed by Pyragas applies an input based on the difference between the current state of the system, which is generating chaos orbits, and the $\tau$-time delayed state, and stabilizes the chaos orbit into a target. In DFC, the information about a position in the state space is unnecessary if the period of the unstable periodic orbit to stabilize is known. There exists the fault that DFC cannot stabilize the unstable periodic orbit when a linearlized system around the periodic point has an odd number property. There is the chaos control method using the prediction of the $\tau$-time future state (PDFC) proposed by Ushio et al. as the method to compensate this fault. Then, we propose a method such as improving the fault of the DFC. Namely, we combine DFC and PDFC with parameter W, which indicates the balance of both methods, not to lose each advantage. Therefore, we stabilize the state into the $\tau$ periodic orbit, and ask for the ranges of Wand gain K using Jury' method, and determine the quasi-optimum pair of (W, K) using a genetic algorithm. Finally, we apply the proposed method to a discrete-time chaotic system, and show the efficiency through some examples of numerical experiments.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.85-88
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• 1996

We develop an efficient technique of controlling chaos using M-step ahead prediction with the OGY method. It has smaller transient time than the OGY method, and prevents burst phenomena that occur in noisy environment. This technique is very simple and needs small memory compared with targeting algorithms. Numerical examples show that the proposed algorithm has good performance, especially in noisy environment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.1015-1017
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• 1996

This paper investigates the chaos secure communication with RLCG transmission line. The synchronization of chaos in two coupled Chua's circuit with RLCG transmission line systems are also studied.

• Kyungpook Mathematical Journal
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• 제54권2호
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• pp.293-320
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• 2014

In this paper, global chaos synchronization is investigated for WINDMI (J. C. Sprott, 2003) and Coullet (P. Coullet et al, 1979) chaotic systems using adaptive backstepping control design based on recursive feedback control. Our theorems on synchronization for WINDMI and Coullet chaotic systems are established using Lyapunov stability theory. The adaptive backstepping control links the choice of Lyapunov function with the design of a controller and guarantees global stability performance of strict-feedback chaotic systems. The adaptive backstepping control maintains the parameter vector at a predetermined desired value. The adaptive backstepping control method is effective and convenient to synchronize and estimate the parameters of the chaotic systems. Mainly, this technique gives the flexibility to construct a control law and estimate the parameter values. Numerical simulations are also given to illustrate and validate the synchronization results derived in this paper.

• 전자공학회논문지CI
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• 제47권3호
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• pp.59-66
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• 2010

본 논문은 불확실한 $L\ddot{u}$ 카오스 시스템의 동기화를 위한 적응 퍼지 bilinear 동기화 제어 설계 방법을 제안한다. $L\ddot{u}$ 카오스 시스템은 알려지지 않은 파라미터를 가지고 있다고 가정한다. 먼저, 불확실한 $L\ddot{u}$ 카오스 시스템을 TS 퍼지 bilinear 모델링을 통해 재구성한다. 불확실한 파라미터를 가진 TS 퍼지 bilinear $L\ddot{u}$ 카오스 시스템을 기반으로한 적응 퍼지 bilinear 동기화 제어 기법을 설계한다. Lyapunov 이론을 통해서 설계된 적응 퍼지 bilinear 동기화 제어 기법을 통한 TS 퍼지 bilinear $L\ddot{u}$ 카오스 시스템과 제안된 슬레이브 시스템 간의 오차 다이나믹 시스템의 안정성을 보장하고 이를 통해서 불확실한 파라미터를 추정 할 수 있는 적응 규칙을 유도한다. 제안된 동기화 제어 기법을 시뮬레이션을 통해서 그 명확성을 보이고자 한다.

• 한국정보통신학회논문지
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• 제8권8호
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• pp.1692-1699
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• 2004

본 논문에서는 카오스 궤적 표면에서 불안정한 리미트 사이클을 가지는 장애물 회피 기법을 제안하였다. 카오스 궤적 표면의 모든 장애물은 불안정한 리미트 사이클을 가지는 Van der Pol 방정식으로 가정하였다. 하나 또는 몇 개의 Van der Pol 장애물과 고정 장애물을 로봇이 피해가는 과정을 결과로 나타내었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.985-989
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• 2005

This paper presents chaos synchronization between two different chaotic systems using nonlinear control method. The proposed technique is applied to achieve chaos synchronization for the Lorenz and Rossler dynamical systems. Numerical simulations are also implemented to verify the results.