• Title/Summary/Keyword: Chaos

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Chaos의 세계(II)

  • 서용권
    • Journal of the KSME
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    • v.31 no.1
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    • pp.68-79
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    • 1991
  • 이 글에서는 다음의 내용에 대하여 알아보았다. Duffing - holmes 방정식에서의 Chaos Logistic map에서의 Chaos 기타 시스템에서의 Chaos 1) Henon map 2) Bouncty bau map (standard map) 3) 진자에서의 Chaos 4) Taylor-Couette유동 5) Fluid drop Chaos 6) Surface wave Chaos Lyapunov 지수 (Exponent)

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New Chaos Map for BER Performance Improvement in Chaos Communication System Using CDSK (상관지연편이변조 방식의 혼돈(Chaos) 통신 방식에서 비트오류율 성능 향상을 위한 새로운 혼돈 지도)

  • 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.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.

A study on Secure Communication in Hyper-Chaos with SC-CNN using Embedding Method

  • Bae, Young-Chul;Kim, Ju-Wan;Song, Hag-Hyun;Kim, Yoon-Ho
    • Journal of information and communication convergence engineering
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    • v.1 no.4
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    • pp.223-228
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    • 2003
  • In this paper, we introduce a hyper-chaos secure communication method using hyper-chaos circuit onsist of State-Controlled Cellular Neural Network SC-CNN). We make a hyper-chaos circuit using SC-CNN with the n-double scroll or Chua's oscillator. A hyper-chaos circuit 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. Hyper-chaos ynchronization was achieved using GS (Generalized Synchronization) method between the transmitter and receiver about each state variable in the SC-CNN. In order to secure communication, we have synthesizing the desired information with a hyper-chaos circuit by adding the information signal to the hyper-chaos signal using the SC-CNN in the transmitter. And then, transmitting the synthesized signal to the ideal channel, we confirm secure communication by separating the information signal and the hyper-chaos signal in the receiver.

A Review on Two-Phase Flow Analysis using Chaos Theory (카오스 이론을 이용한 2상 유동 해석)

  • Kwon, Jeong-Tae;Kwon, Young-Chul;Kim, Kyoung-Min
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.56 no.1
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    • pp.23-27
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    • 2007
  • This article presents a review on chaos analysis of two-phase flow. Chaos theory has recently been applied to two-phase flow analysis, and it gives promising measures to quantitatively identify two-phase flow patterns and pool boiling behaviors. But, consistency of the calculated chaotic measures were not completely confirmed yet. More experimental data are requested for chaos analysis of two-phase flow. Also, chaos analysis methodology should be developed by experimental verification.

A study on Generalized Synchronization in Hyper-Chaos with SC-CNN

  • Bae, Young-Chul;Kim, Ju-Wan;Song, Hag-Hyun;Kim, Yoon-Ho
    • Journal of information and communication convergence engineering
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    • v.1 no.4
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    • pp.217-222
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    • 2003
  • In this paper, we introduce a hyper-chaos synchronization method using hyper-chaos circuit consist of State-Controlled Cellular Neural Network (SC-CNN). We make a hyper-chaos circuit using SC-CNN with the n-double scroll. A hyper-chaos circuit 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. Hyper-chaos synchronization was achieved using GS(Generalized Synchronization) method between the transmitter and receiver about each state variable in the SC-CNN.

Research on the Image Encryption Method using a Linear-structure Chaos System (선형구조 혼돈계를 이용한 이미지 암호와 방법 연구)

  • Cho, Chang Ho;Yim, Geo Su
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.7 no.4
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    • pp.75-79
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    • 2011
  • With the rapid growth of digital communication and the internet, the importance of conducting research on data encryption methods is increasing. Some of the pertinent researches that have been conducted so far introduced data encryption methods using chaos systems, and numerous researches are currently being conducted on such methods. The signals produced by the chaos systems are called "determined noise," and if this is applied to data encryption, very effective results can be obtained. Using the Henon map, the relationship between the non-linearity of the chaos system and the strength of encryption was analyzed, and a linear-structure chaos system that uses non-linearity as a variable for encryption strength was constructed. Using the constructed chaos system, an image was encrypted and decoded, and the correlation coefficient of the linear-structure chaos system's performance was calculated and then analyzed.

Effects of Household Chaos on Preschoolers' Aggression and Prosocial Behavior: Sleep Problems and Executive Function as Mediators (가정 내 혼란이 유아의 공격성과 친사회적 행동에 미치는 영향: 수면문제와 실행기능의 매개효과)

  • Bomi Lee;Jeeun Noh;Nana Shin
    • Human Ecology Research
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    • v.61 no.1
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    • pp.1-13
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    • 2023
  • Household chaos, represented by high levels of disorganization and instability in the home, has been linked with suboptimal outcomes for preschoolers. The aim of this study was to examine the roles that sleep problems and executive function play in the association between household chaos and preschoolers' aggression and prosocial behavior. The sample for the study consisted of 420 preschoolers and their mothers. The mothers provided reports on the level of chaos in the home and their preschoolers' sleep problems, executive function, and social behavior, including aggression and prosocial behavior. The data was analyzed using structural equation modeling. When preschoolers' sleep problems and executive function were included in the model as mediators, the results indicated that household chaos did not have direct effects on preschoolers' aggression and prosocial behavior. Such effects were instead serially mediated by preschoolers' sleep problems and executive function, respectively. The higher the degree of household chaos, the more preschoolers displayed sleep problems and deficits in executive function, resulting in more aggression and less prosocial behavior. The findings from this study emphasize the significance of reducing household chaos in order to reduce preschoolers' aggression and promote prosocial behavior. They also underscore the need to identify additional variables that mediate the impact of household chaos on preschoolers' social outcomes.

The secure communication in hyper-Chaos

  • Youngchul Bae;Kim, Juwan;Kim, Yigon
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2003.09a
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    • pp.575-578
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    • 2003
  • In this paper, we introduce a hyper-chaos secure communication method using Hyper-chaos consist of State-Controlled Cellular Neural Network (SC-CNN). A hyper-chaos circuit is created by applying identical n-double scroll with weak coupled method to each cell. Hyper-chaos synchronization was achieved using embedding synchronization between the transmitter and receiver about in SC CNN. And then, we accomplish secure communication by synthesizing the desired information with a hyper-chaos circuit by embedding the information signal to the only one state variable instead of all state variables in the driven-synchronization method. After transmitting the synthesized signal to the identical channel, we confirm secure communication by separating the information signal and the hyper-chaos signal in the receiver.

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CHAOS AND LYAPUNOV EXPONENT

  • Yu, Se-Ra;Kim, Yon-Mi
    • The Pure and Applied Mathematics
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    • v.7 no.2
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    • pp.87-100
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    • 2000
  • In this paper, we try to approach chasos with numerical method. After investigating nonlinear dynamcis (chaos) theory, we introduce Lyapunov exponent as chaos\`s index. To look into the existence of chaos in 2-dimensional difference equation we computes Lypunov exponent and examine the various behaviors of solutions by difurcation map.

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Obstacle Avoidance Method in the Chaotic Unmanned Aerial Vehicle (카오스 무인 비행체에서의 장애물 회피 방법)

  • Bae, Young-Chul;Kim, Yi-Gon;Kim, Chun-Suk
    • Journal of the Korean Institute of Intelligent Systems
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    • v.14 no.7
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    • pp.883-888
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    • 2004
  • In this paper, we propose a method to avoid obstacles that have unstable limit cycles in a chaos trajectory surface. We assume all obstacles in the chaos trajectory surface have a Van der Pol equation with an unstable limit cycle. When a chaos UAVs meet an obstacle in an Arnold equation, Chua's equation and hyper-chaos equation trajectory the obstacle reflects the UAV( Unmanned Aerial Vehicle).