• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.382-385
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• 1996

디지탈 신호처리에 혼돈 신호를 적용하기 위해 선형 확산 결함(coupled linear diffusion)을 이용하여, 궤도 (trajectory)의 혼돈적인 고유특성은 변함이 없고 주파수 만 체배관계에 있는 4가지 혼돈 신호들을 발생시켰다. 혼돈 신호들을 발생시키기 위한 기본 혼돈 회로로는 Chua 회로를 사용하였고, 이 혼돈 신호들을 복극 4레벨 방식에 응용하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.2
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• pp.137-143
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• 2011

The pitch motion of a gravity-gradient satellite can be chaotic, depending on the ratio of mass moments of inertia and the eccentricity of the satellite orbit. For a precise prediction of motion, chaotic pitch motion has to be changed to non-chaotic motion. Feedback control can be used to obtain nonchaotic pitch motion. For chaos control and stabilization of the pitch motion of a gravity-gradient satellite, a feedback control system is designed, based on the linear nonautonomous system obtained by linearizing the nonlinear pitch motion. The control law obtained has two parameters and is applied to chaotic nonlinear pitch motion. The nonlinear control system satisfies the proposed control objectives in the range of the nonchaotic parameter space.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.8
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• pp.629-637
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• 2013

Chaos communication systems have the characteristics such as non-periodic, wide-band, non-predictability of signals and easy implementation. There have been many studies about chaos communication systems because of these advantages. But, chaos communication systems have low BER(Bit Error Rate) compare to general digital communication system. Existing researches on chaos communication systems only analyze BER performance according to various chaos maps. There are no studies on analysis of BER performance according to PDF(Probability Density Function) of chaos maps. In this paper, we analyze the BER performance according to changing parameter, equation, and initial values of chaos map's PDF. In addition, we propose new chaos map to improve BER performance. Simulation results show that BER performance of CDSK(Correlation Delay Shift Keying) is changed when PDF of chaos map changed. And the proposed chaos map has a better BER performance compare to previous chaos maps such as Tent map, Logistic map, and Henon map.

• The Journal of Natural Sciences
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• v.9 no.1
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• pp.75-81
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• 1997

The method of synchronization by feedbacking a signal of master system to a corresponding variable of slave system is applied to the Lorenz which is autonomous system. The two Lorenz systems are synchronized and the synchronization occurs when the consisting of the variable differences of the two systems generates infinite period of laminar phase. The characteristics of synchronization is analyzed in time series and phase spaces.

• Convergence Security Journal
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• v.8 no.3
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• pp.57-64
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• 2008

The Security of digital images has become increasingly more important in highly computerized and interconnected world. Therefore, The chaos-based encryption algorithms have suggested some new and efficient ways to develop secure image encryption method. This paper is described for the point at issue in all chaos-based encryption method for distribution of a chaotic signals. It has a method for generation of uniformly distributed chaotic signals that we designed secure algorithm of multi-parameter chaotic systems. So we are present validity of the theoretical models for results of image encryption and decryption for proposed method.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.248-249
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• 2000

최근 "혼돈제어"라는 몇 가지 방식이 증명되어 여러 시스템에서 혼돈스런 출렁임을 제거하게 되었다. 처음으로 OGY(Ott Grebogi Yorke) 방법에 기초를 둔 Occasional Proportional Feedback(OPF) 방식이 Roy에 의해 고체레이저 system 에 적용되었다$^{(1)}$ . 또 High Frequency Injection(HFI) 방식으로도 혼돈을 제어할 수 있음이 발표되기도 했다$^{(2),(3)}$ . 우리의 실험에서는 단일모드로 발진하는 Nd:YAG 레이저에서 일어나는 혼돈현상을 관측하려 한다. (중략)

• Journal of Advanced Navigation Technology
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• v.17 no.3
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• pp.292-297
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• 2013

In this paper, The design of digital circuits for chaotic composition function which is used for the key-stream generator is studied in this work. The overall design concept and procedure due to the mathematical model of chaotic key-stream generator is to be the explained in detail, and also the discretized truth table of chaotic composition function is presented in this paper. consequently, a composition state machine based on the compositive map with connecting two types of one dimensional and two dimensional chaotic maps together is designed and presented.

• The Journal of Natural Sciences
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• v.6 no.1
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• pp.79-87
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• 1993

In the map of period-doubling bifurcation, stable fixed points bifurcate to $2^n$ fixed points, and in the chaotic region, the chaotic bands merge to 1/$2^n$ bands. In a typical map, the chaotic bands expand to a broad chaotic band during the merging process, so called crisis. In this paper, interior crises appearing during the merging process will be discussed by using our map and will be analyzed the characteristics of the phenomenon by obtaining the Lyapunov Exponents.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.652-657
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• 2013

In this paper the design methode of a separated composition state machine based on the compositive map with two chaotic maps together and the result of that is proposed. The digital circuits of chaotic composition map for the use of chaotic binary stream generator are designed in this work. The discretized truth table of chaotic composition function which is composed of two chaotic functions - the saw tooth function and skewed logistic function - is made out, and also simplefied Boolean algebras of digital circuits are obtained as a mathematical model. Consequently, the digital circuits of the map for chaotic composition function are presented in this paper.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.10
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• pp.1125-1130
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• 2014

The quantity and quality of contents containing information are sharply increasing with the rising network speed. In line with this rapid growth of information volume, a new communication protocol using the chaotic signal that can protect contents in communication is proposed as follows. The chaos system has the characteristic of unpredictability due to the sensitive initial values and the similarity of the signals with noise. We configured two chaos systems $F(X_n,Y_n)$ and $G(A_n,B_n)$ that have such characteristics and designed a data communication method using as encryption channel the same chaos signals generated by synchronizing the chaos system G with the F signals. The proposed method was verified with the encryption and decryption of images. The proposed method is different from the existing encrypted communication methods and is expected to lay the foundation for future studies in related areas.is an example of ABSTRACT format.