A Dissertation Submitted To Guangdong University Of Technology For The Degree Of Doctor Of Philosophy

Ever since Lorenz found the first chaotic attractor in 1963, chaos as a main subject of theoretical research has been continuously investigated within the natural sciences, mathematics and engineering. Recently, this study has evolved from the traditional trend of understanding and analyzing chaos to a new direction of controlling and utilizing toward engineering and technological application such as chaos mixing, chaos-based encryption and secure communication. In a broader sense, chaos control refers not only to weakening or completely suppressing chaos when it is harmful, but also to generating or modifying existing chaos when it is useful, name as hyperchaos anticontrol or chaotification.Hyperchaos was first reported by Rossler in 1979. Since then, interest in studying hyperchaos generator has been significant increased. A hyperchaotic attractor is usually characterized as a chaotic attractor with more than one positive Lyapunov exponent. The dynamics of such attractor expand in more than one direction, giving rise to "thicker" and "more complex" chaotic dynamics. Due to its increased degree of randomness and higher unpredictability, it is found to be great potential useful for some nontraditional engineering and technological applications, such as chaos-based encryption and secure communication. Hyperchaotification, in contrast to ordering or suppressing chaos, is to make a original chaotic but non-hyperchaotic dynamical system hyperchaotic. In particular, purposefully designing a hyperchaotic system from an originally chaotic system with some simple means, is theoretically very attractive and yet technically challenging, as highly complex chaotic behavior is commonly involved and there does not seem to be any systematic methodology for purposefully designing a hyperchaotic system to date.This paper presents the finding of a new hybrid chaotic attractor and some new hyperchaotic generators, the control and synchronization are also investigated.A new hybrid chaotic system is presented, which is generated by using switching control or |x| function. The new unified chaotic system has a compound structure by merging together a Lorenz's swing and a Chen's swing. This property can be used in chaotic digital modulation, in which information symbol "1" is mapped on the wing of Lorenz chaotic attractor while the symbol "0" is mapped on the wing of Chen chaotic attractor. The modulation method can enhance the complexity of modulated...