Papers by Keyword: Chaos

Abstract: The chaotic characteristics of high-dimensional chaotic system are more complex, so the design of chaotic system with higher dimension has become a leading subject of chaos theory. In this paper, we constructed a nine-dimensional eight-order chaotic system. Matlab simulation of system is performed and Lyapunov exponents are figured out, which proved more complex dynamical behaviors. And the corresponding hardware circuit is designed. Multisim simulation results of the circuit coincide with Matlab simulation of the system completely, showing the same chaotic attractors. The consistent results verified the realizability of system. Therefore, the system can provide a more secure encryption source for information encryption.

Abstract: In order to improve the detection performance with the limited radar resources in the given defense zone, it is necessary to make reasonable and effective deployment of radar network. According to the principles of radar network deployment, its mathematical model is established at the beginning. And then, on the base of the shuffled frog leaping algorithm (SFLA) principle, a new method-improved shuffled frog leaping algorithm (ISFLA) is introduced through the technique of algorithm hybrid. By integrating updated strategy and chaotic optimization into SFLA, it greatly enhances the local searching efficiency and global searching performance. Moreover, the frogs are divided into two types and perform different operations to co-evolve. Finally, by analyzing an example and comparing the results with those algorithms, it comes to a conclusion that several network schemes can be obtained much more quickly by this way with better operability.

Abstract: Based on Helmholtz-Duffing which is a typical nonlinear asymmetric dynamical system, According to homoclinic bifurcations, prerequisites for chaos motion are obtained by use of Melnikov theory. As a result of verifying the analytic solutions, the safe basin and the phenomena of erosion of the safe basin are simulated by numerical method in the end. The research indicates that the value range of is closely related to the area influenced by the value itself: when is located in the range of from zero to one, the left part of system is mainly affected; when is larger than one, the right part of system is mainly affected. For the same symmetry parameter , there exist a critical frequency at which the threshold value of the amplitudes of both left and right part of system are equal.

Abstract: The nonlinear dynamic differential equation of 2K-H planetary gear transmission, which takes into consideration of clearance, is presented in this paper. Various Chaotic characteristics of the system are collected, such as the Largest Lyapunov Exponent and the phase locus. Experimental simulation is carried out and the periodic movement, quasi periodic movement and chaotic movement of the system are gotten under different parameters.

Abstract: With the crank-and-rod exciters, the vibrational conveyers have a trough supported on elastic stands which are rigidly fastened to the trough and a supporting frame. The trough is oscillated by a common crank drive. This vibration causes the load to move forward and upward. The movement is strictly related to vibrational parameters. In this study is the transitional behavior across resonance, during the starting of a single degree of freedom vibratory system excited by non-ideal DC motor. The mechanical system depends on the motion of the DC motor. The working rang of vibrational conveyers with cubic nonlinear spring and non-ideal vibration exciter has been analyzed analytically for primary resonance by the Method of Multiple Scales. Lyapunov exponents are numerically calculated and the results of numerical simulation are ploted.

Abstract: In the area of mechanics and electronics, the behaviors of mechanical systems under periodic loadings have been examined by many researchers. Vertical conveyors are effective examples observing various kinds of parameters of this problem. In this study, the nonlinear analysis of unbalanced mass of vertical conveyor with non-ideal DC motor has been analyzed. The results of numerical simulation are plotted and Lyapunov exponents are calculated.

Abstract: In this paper, we analyzed chaotic dynamics of an electromechanical damped Duffing oscillator coupled to a rotor. The electromechanical damped device or electromechanical vibration absorber consists of an electrical system coupled magnetically to a mechanical structure (represented by the Duffing oscillator), and that works by transferring the vibration energy of the mechanical system to the electrical system. A Duffing oscillator with double-well potential is considered. Numerical simulations results are presented to demonstrate the effectiveness of the electromechanical vibration absorber. Lyapunov exponents are numerically calculated to prove the occurrence of a chaotic vibration in the non-ideal system and the suppressing of chaotic vibration in the system using the electromechanical damped device.

Abstract: Low-dimensional chaotic encryption has a good operational efficiency but there is a problem of security flaws, therefore this paper proposes a composite chaos encryption system based on double mapping. Double mapping with mutual disturbance were used to generate the key sequence, and respectively with odd and even number of image pixels to realize the image encryption. The simulation results show that, the effect is very good; Correlation and so on security analysis shows that meet the requirements of the security; System overall evaluation results show that the proposed algorithm has better security and ease of implementation, can effectively resist brute force attack, statistic attack etc.

Abstract: In the paper, according to crushing and attrition of material on mixer blade, the mechanical model of material on blade is established. According to nonlinear vibration and the basic theory of rotor dynamics, Mechanical model of vibration system and differential equations of motion are established. This paper has adopted the arithmetic of fourth-order Runge-Kutta, analyzing wave forms graph, chart of axis track, phase plane plot of system movement. Analysis results show that mixer system appears chaotic motion under some certain design parameters. This state of motion on mixers can better destroy cement coagulation group, increasing the number of effective collision of concrete particle, which can effectively improve the microscopic homogeneity of concrete and improve efficiency of concrete mixing.

Abstract: In order to improve the security performance of the information stored in Quick Response (QR) code, this paper introduces an improved RC4 algorithm which can be used in the encryption of QR code. We add the self-error detection stage into fault induction attack resistence and combine Chaos with enhanced pseudo-randomness in the stage of PRGA. The experimental results show that the new method proposed in this paper has several advantages in security and reliability.