• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 1999년도 춘계종합학술대회
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• pp.313-318
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• 1999

Pecora와 Carroll[10]이 제시한 구동 동기 이론을 적용하여 전송선로를 가진 Canonical Chua 회로에서 카오스 동기화가 이루어짐을 확인하였다. Pecora와 Carroll[10]이 제시한 구동 동기 이론은 동기될 한쌍의 카오스 회로를 구동 응답 시스템이라 하면 구동 시스템의 상태 변수 중 몇 개의 상태 변수만을 응답 시스템으로 전송하면 전송된 몇 개의 상태 변수들에 의해 전송되지 않은 나머지 상태 변수들을 가지고 응답 시스템에 나타나게 하여 동기를 이루는 방법으로 이때 응답 시스템 회로에는 불필요한 부분이 존재한다. 본 논문에서는 이 불필요한 부분을 제거하고 이를 전송 선로로 치환하여 Chua 회로의 구동부와 응답부 사이에 놓아 전송선로를 구성하여 카오스 동기화가 이루어짐을 시계열 데이터와 위상 공간으로 확인하였으며 이 결과를 이용하여 카오스 암호화 통신에 이용할 수 있을 것으로 보인다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 추계종합학술대회
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• pp.459-462
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• 2000

The analysis of distribution line faults is essential to the proper protection of power system. A high impedance fault(HIF) dose not make enough current to cause conventional protective device operating. so it is well hon that undesirable operating conditions and certain types of faults on electric distribution feeders cannot be detected by using conventional protection system. In this paper, we prove that the nature of the high impedance faults is indeed a deterministic chaos, not a random motion Algorithms for estimating Lyapunov spectrum and the largest Lyapunov exponent are applied to various fault currents detections in order to evaluate the orbital instability peculiar to deterministic chaos dynamically, and fractal dimensions of fault currents which represent geometrical self-similarity are calculated. Wavelet transform analysis is applied the time-scale information to fault signal. Time-scale representation of high impedance faults can detect easily and localize correctly the fault waveform.

• Journal of information and communication convergence engineering
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• 제2권4호
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• pp.237-242
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• 2004

In this paper, we introduce a complex systems synchronization method using hyper-chaos circuit consist of State-Controlled Cellular Neural Network (SC-CNN). We make a complex systems using SC-CNN with the n-double scroll. A complex system is created by applying identical n-double scroll or non-identical n-double scroll and Chua's oscillator with weak coupled method to each cell. Complex systems synchronization were achieved using GS(Generalized Synchronization) method between the transmitter and receiver about each state variable in the SC-CNN.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.817-821
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• 1997

Ever since the nonlinearity of machine tool dynamics was established, researchers attempted to make use of this fact to devise better monitoring, diagnostics and system, which were hitherto based on linear models. Theory of chaos, which explains many nonlinear phenomena comes handy for furthering the analysis using nonlinear model. In this study, measuring system will be constructed using multi-sensor (Tool Dynamometer, Acoustic Emission) in end millingprocess. Then, it will be verified that cutting force is low-dimensional deterministic chaos calculating Lyapunov exponents, Fractal dimension, Embedding dimension. Aen it will be investigated that the relations between characteristic parameter caculated form sensor signal and tool wear.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.228-230
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• 1997

Recently, as power systems become large and complicated, chaos theory has been introduced to analyze their nonlinear characteristics. In this paper, voltage collapse phenomenon is more accurately analyzed using bifurcation theory of chaos. Chaotic behaviors has been observed in computer simulation for a simple power system over a range of loading conditions. Besides existence of voltage collapse point in critical value, operation of power system in Hopf window can be the cause of voltage collapse.

• 한국정밀공학회지
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• 제14권11호
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• pp.93-101
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• 1997

Ever since the nonlinearity of machine tool dynamics was established, researchers attempted to make use of this fact to devise better monitoring, diagnostics and control system, which were hitherto based on linear models. Theory of chaos which explains many nonlinear phenomena comes handy for furthering the analysis using nonlinear model. In this study, measuring system will be constructed using multi-sensor (Tool Dynamometer, Acoustic Emission) in end milling process. Then, it will be verified that cutting force is low-dimensional chaos by calculating Lyapunov exponents. Fractal dimension, embedding dimension. And it will be investigated that the relation between characteristic parameter calculated from sensor signal and tool wear.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 B
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• pp.633-635
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• 1997

In this paper, a transmitter and a receiver using two identical Chua's circuits are proposed and a wire synchronizations are investigated. As several problems have been found in both the drive-response synchronization and the coupled synchronization in the previous researches, a new drive-coupled synchronization theory is proposed that can be applicable to wire communication. Since the synchronization of the wire transmission system is impossible by coupled synchronization, theory having both the drive-response and the coupled synchronization is proposed. As a result, the chaos synchronization has delay characteristics in the wire transmission system caused by the line parameters L and C.

• Advances in nano research
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• 제15권1호
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• pp.25-34
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• 2023

This paper investigates the dynamics and stability of steady states in a continuous and discrete-time single-mode laser system. By using an explicit criteria we explored the Neimark-Sacker bifurcation of the single mode continuous and discrete-time laser model at its positive equilibrium points. Moreover, we discussed the parametric conditions for the existence of period-doubling bifurcations at their positive steady states for the discrete time system. Both types of bifurcations are verified by the Lyapunov exponents, while the maximum Lyapunov ensures chaotic and complex behaviour. Furthermore, in a three-dimensional discrete-time laser model, we used a hybrid control method to control period-doubling and Neimark-Sacker bifurcation. To validate our theoretical discussion, we provide some numerical simulations.

• 한국지능시스템학회논문지
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• 제16권1호
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• pp.18-23
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• 2006

복잡계에서의 동기화는 기본적으로 카오스 신호에서의 동기화 이론에 근거를 두고 발전하고 있으나 복잡계 신호의 복잡도가 카오스 신호보다 복잡도가 커서 동기화하는데 어려움이 많다. 이에 본 논문은 복잡계에서 동기화 기법을 적용하기 위하여 n-double 스크롤 회로에서는 결합 동기 이론을 적용한 동기화 기법과 여러 개의 파라미터 중 하나의 파라미터만을 가지고 동기화를 이루는 새로운 임베딩 구동 동기화 기법을 복잡계 회로의 하나인 하이퍼카오스 회로에서 제안하였다. 제안한 동기화 기법을 적용한 결과 복잡계에서 우수한 동기화 결과를 얻었음을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.41-46
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• 2015

It is very important to make accurate forecast of wind power because of its indispensable requirement for power system stable operation. The research is to predict wind power by chaos and BP artificial neural networks (CBPANNs) method based on genetic algorithm, and to evaluate feasibility of the method of predicting wind power. A description of the method is performed. Firstly, a calculation of the largest Lyapunov exponent of the time series of wind power and a judgment of whether wind power has chaotic behavior are made. Secondly, phase space of the time series is reconstructed. Finally, the prediction model is constructed based on the best embedding dimension and best delay time to approximate the uncertain function by which the wind power is forecasted. And then an optimization of the weights and thresholds of the model is conducted by genetic algorithm (GA). And a simulation of the method and an evaluation of its effectiveness are performed. The results show that the proposed method has more accuracy than that of BP artificial neural networks (BP-ANNs).