• Title, Summary, Keyword: 카오스

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Secure Communication of HyperChaos Circuits using SC-CNN (SC-CNN을 이용한 하이퍼카오스 회로에서의 비밀 통신)

  • Bae, Young-Chul;Kim, Ju-Wan
    • Proceedings of the KIEE Conference
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    • pp.2158-2160
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    • 2003
  • 본 논문에서는 동일동기화(Identical Synchronization)과 일반동기화(General Synchronization)를 이용한 하이퍼카오스 시스템을 구성하고 검증하였다. 단일 카오스 모듈을 이용한 통신은 많은 보안의 취약점을 가진 것으로 알려져 있다. 이에 이런 취약점을 보안하기 위해 여러 방법들이 도입되었다. 본 논문은 두 개의 2-double scroll Chua 회로와 두 개의 2-double scroll Chua 오실레이터를 이용하여 하이퍼카오스 회로의 송수 신단을 구성하고 동기화를 이룬 후 송신단에서 정보신호를 실어 채널을 통해 보내어 수신단에서 이를 복조하는 방법을 제안하였다.

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Study of Chaotic Mixing for Manufacturing Uniform Mixtures in Extrusion Processes (Development of New Numerical Mapping Methods) (압출공정에서의 균일한 혼합체 제조를 위한 카오스 혼합연구)

  • 김은현
    • The Korean Journal of Rheology
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    • v.8 no.3_4
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    • pp.187-198
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    • 1996
  • 최근에 본 연구자에 의해서 단축 스크류 공정에서 카오스 스크류라고 명명되어진 카오스 혼합장치가 성공적으로 개발되었다. 기하학적 조건이나 공정조건에 대한 설계변수로 카오스 스크류를 설계하기 위하여 체류시간, 포인카레 단면 그리고 혼합패턴등에 대한 계산 과 해석이 이루어져야 하는데 이를 단지 Runge-Kutta 방법에 의해 속도장을 적분한다면 상당한 계산시간이 소비된다. 이러한 수치문제를 극복하기 위하여 본논문에서는 새로운 사 상법을 제안한다. 이 방법으  사용하면 벽면 근처의 특이점 영역에서도 수치문제가 해결된 다. 본 논문에서 제안하는 수치사상법은 Runge-Kutta 방법에 비하여 수치계산의 효율성과 정확도 면에서, 특히 유안요소법으로 얻은 속도장에 대하여 우수함이 밝혀졌다. 이러한 사상 법은 공간주기 유동장뿐만 아니라 시간주기 유동장에서 적용할수 있다.

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Application of the Instantaneous Lyapunov Exponent and Chaotic Systems, Part 2: Experiment and Comparison with the Force-State Mapping Method (순간 발산지수의 카오스계에의 응용, 파트 2: 실험 및 힘-위상(Force-State Mapping) 방법과의 비교)

  • Shin, Ki-Hong
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.1
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    • pp.150-160
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    • 1999
  • 본 논문은 ‘파트 1’에 그 기초를 두었으며, 실제 실험 상황에의 응용예를 들었다. 보편적인 ‘이중-우물 위치 진동기(double-well potential vibrator)'를 외부 공기압 감쇠기를 장치할 수 있도록 수정하였다. 감쇠는 높음 또는 낮음 으로 조정할 수 있도록 하였다. 이 실험계는 주기운동부터 카오스 운동까지 다양한 동적 특성을 보여준다. 힘-위상(Force-Stare Mapping) 방법이 선형상태 및 카오스상태에 응용되었으며, 특히 감쇠의 높고 낮음의 파악에 그 중점을 두었다. 그리고 , 부분발산지수들(Short term averaged Lyapunov exponents)의 합이 또한 감쇠를 파악함과 동시에 높은 감쇠에서 낮은 감쇠로의 변화를 감시할 수 있음을 보였다. 이 두가지 방법들을 비교하였으며 논하였다.

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Electronic Circuit Analysis of the Lorentz Chaotic System for Engineering Applications (공학적 응용을 위한 로렌츠 카오스 시스템의 전자회로 해석)

  • Han, Sang-Baek;Jo, Mun-Kyu;Song, Han-Jung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.1
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    • pp.311-316
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    • 2012
  • In this paper, chaotic circuit of the Lorentz system for engineering applications was implemented using resistor, multipliers, capacitors and operational amplifiers. The implemented Lorentz chaotic system was analysed by PSPICE program. PSPICE simulation results show many kind of chaotic phenomena such time waveforms and phase plots. Meanwhile, according to resistor's variation, we got that Lorentz system show equilibrium state, periodic state and chaotic state.

Scrambling Chaotic On Off Keying Modulation Scheme for Security Improvement (보안성 향상을 위한 스크램블링 COOK 변조 방식)

  • Lee, Jun-Hyun;Lee, Dong-Hyung;Keum, Hong-Sik;Ryu, Heung-Gyoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39A no.6
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    • pp.303-309
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    • 2014
  • Chaos communication system can improve a system security due to characteristics of non-periodic, non-predictability, broadband signal and easy implementation. Also, chaos signal is sensitive to initial conditions of chaos map. By these reasons, security of chaos communication system is superior to digital communication system. BER performance of COOK modulation system is better than other chaos modulation systems, even if COOK modulation system uses an asynchronous receiver. However, security and safety of COOK modulated signal are worse than other chaos modulation systems, because information bits can be easily predicted from COOK modulated signal. In this paper, for security improvement of COOK modulated signal, we propose a novel Scrambling COOK modulation system by applying the scrambling method. Conventional COOK modulated signal can be predicted, because chaos signal is generated when data is only 1. However, proposed system cannot be predicted, because chaos signal is generated when data is 0 or 1. Therefore, security and safety of transmitted signal in scrambling COOK modulation system is superior to conventional COOK modulation system.

A Novel Design of CDSK Receiver for Improving the BER Performance (BER 성능 향상을 위해 제안하는 새로운 CDSK 수신기)

  • Lee, Jun-Hyun;Ryu, Heung-Gyoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.8
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    • pp.638-643
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    • 2013
  • Chaos communication system has a sensitive characteristic to initial conditions, because completely another signal is generated when initial condition of chaos equation is changed subtly. Also, chaos communication systems have the characteristics of non-periodic, non-predictability, the broadband signal, such as ease of implementation. Due to these characteristics, security of chaos communication system generally is evaluated better than other systems. However, BER(Bit Error Rate) performance is evaluated worse than other digital system, because existing chaos communication system's transmitter and receiver are strong influence by interference signal and noise. So, research to improve the BER performance of the chaotic communication system is performed continuously. In this paper, We will propose a new CDSK(Correlation Delay Shift Keying) receiver for BER performance improvement. After we compare to the performance of existing CDSK receiver and proposed CDSK receiver, BER performance of proposed CDSK receiver evaluate. Also, when using the new CDSK receiver, we evaluate the BER performance according to the spreading factors and find an optimum spreading factor. If chaos communication system use a new CDSK receiver, BER performance is improved than existing CDSK receiver. Also, if spreading factor's value is increased, BER performance is improved, because it is not nearly affected by interference signal and noise.

Adaptive Fuzzy Bilinear Synchronization Control Design for Uncertain $L\ddot{u}$ Chaos System (불확실한 $L\ddot{u}$ 카오스 시스템을 위한 적응 퍼지 Bilinear 동기화 제어 설계)

  • Baek, Jae-Ho;Lee, Hee-Jin;Park, Mig-Non
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.47 no.3
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    • pp.59-66
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    • 2010
  • This paper is proposed an adaptive fuzzy bilinear synchronization design for uncertain $L\ddot{u}$ chaos system. It is assumed that the $L\ddot{u}$ chaos system has unknown parameters. First, The $L\ddot{u}$ chaos system can be reconstructed via TS fuzzy bilinear modeling. We design an adaptive fuzzy bilinear synchronization control scheme based on TS fuzzy bilinear $L\ddot{u}$ chaos system with uncertain parameters. Lyapunov theory is employed to guarantee the stability of error dynamic system between TS fuzzy bilinear $L\ddot{u}$ chaos system and the proposed slave system and to derive the adaptive laws for estimating unknown parameters. Simulation results is given to demonstrate the validity of our proposed synchronization scheme.

Design of digital communication systems using DCSK chaotic modulation (DCSK 카오스 변조를 이용한 디지털 통신 시스템의 설계)

  • Jang, Eun-Young
    • The Journal of the Korea institute of electronic communication sciences
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    • v.10 no.5
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    • pp.565-570
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    • 2015
  • Spread spectrum communications have increased interest due to their immunity to channel fading and low probability of intercept. One of the limitations of the traditional digital spread spectrum systems is the need for spreading code synchronization. Chaotic communication is the analogue alternative of digital spread spectrum systems beside some extra features like simple transceiver structures. In this paper, This paper was used instead of the digital modulation and demodulation carriers for use in the chaotic signal in a digital communication system among the chaotic modulation schemes, the Differential Chaos Shift Keying(DCSK) is the most efficient one because its demodulator detects the data without the need to chaotic signal phase recovery. Also Implementation of Differential Chaos Shift Keying Communication System Using Matlab/Simulink and the receiver con decode the binary information sent by the transmitter, performance curves of DCSK are given in terms of bit-error probability versus signal to noise ratio with spreading factor as a parameter and we compare it to BPSK modulation.

Anti-Jamming Performance of Chaos Communications System Using DCSK and CDSK Modulation Method (DCSK와 CDSK 방식을 사용하는 카오스 통신 시스템의 항재밍 특성)

  • Lee, Jun-Hyun;Ryu, Heung-Gyoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.4
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    • pp.417-425
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    • 2013
  • Digital communication technology have been focused on the higher data efficiency and the effective coding of information. Also, it is very important to improve security and minimize the interference of the external sources, Chaos communications system is studied to improve security and minimize the interference by effective encoding of information in the nonlinear systems such as DCSK(Differential Chaos Shift Keying) and CDSK(Correlation Delay Shift Keying). In this paper, we evaluate anti-jamming performance of chaos communications system using the DCSK and CDSK system. The simulation results show that the Gauss iterated map has better BER performance than the other maps(tent map, logistic map, Henon map). Also, DCSK and CDSK system can get the better anti-jamming performance by applying different chaotic maps.

Design of FM-QCSK Chaotic Communication System for high-speed communication (고속통신을 위한 FM-QCSK 카오스 통신 시스템)

  • Jang, Eun-Young
    • The Journal of the Korea institute of electronic communication sciences
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    • v.10 no.10
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    • pp.1183-1188
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    • 2015
  • The FM-QCSK(: Frequency Modulated Quadrature Chaos Shift Keying) system is one of the most efficient systems in chaotic literature. One of the problems in this system is that half the bit duration is used for sending a chaotic reference signal which leads to increase the energy losses and reduces the data rate. In this paper, a novel scheme to enhance the performance of FM-QCSK system has been proposed. With the proposed scheme, FM-QCSK would be able to operate at higher data rates with reduced BER(: Bit Error Rate) and energy consumption. The basic modification introduced by the proposed scheme is the use one reference chaotic signal to transmit multi information signals in both in-phase and quadrature-phase channels. The results showed that the proposed scheme have achieved more than 3 dB gains in SNR for AWGN channels respectively at $BER=10^{-3}$ over the conventional one. The results also showed that the optimum number information signals can be send per reference signal is 8.