Papers by Keyword: Chaos

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Authors: Jin Lei Liu, Shu Li Guo, Li Na Han
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.
Authors: Zheng Jie
Abstract: In this paper, the chaotic optimization algorithm is embedded in traditional PSO algorithm using randomness and ergodicity of the chaotic characteristic, and random numbers and a inertia weight factor in PSO algorithm is substituted respectively by chaotic variables and an adaptive inertia weight function, so the ACEPSO algorithm is proposed in order to overcome the drawbacks of CPSO algorithm that easily falls into local optimum. With the simulation experiments, the effectiveness of ACEPSO algorithm is verified by optimization tests with the complex multi-dimensional function. The simulation results verify that the ACEPSO algorithm is robust, high precision, and strong global convergence, and is a kind of practical and feasible optimization algorithm.
Authors: Zai Ping Chen, Peng Fei Cai, En Zeng Dong
Abstract: Proposed a chaotic cellular neural network system, in-depth study of the system dynamic characteristics through theoretical analysis and simulation, to obtain the system Lyapunov exponent spectrum, also designed the hardware circuit, and get the physical implementation of chaos system through the FPGA, observing all kinds of chaotic attractor. The experimental results are fully consistent with the Matlab simulation results, thus this physical implementation is correct and feasible.
Authors: Juhn Horng Chen, Long Jye Sheu, Tzu Yi Tung, Hsien Keng Chen, Horng Shing Chiou, Wei Tai Weng
Abstract: We propose a new perspective on image encryption using chaotic signal and blind source separation. The original image is permuted by the chaotic signal and then mixed with key images. In the receiver, blind source separation technique is used to separate the components of the original image from the ciphertexts. Then chaotic signal is again used to restore the pixels to recover the original image. The experimental results demonstrate that the key space is large enough to resist the brute force attack and the distribution of gray values of the encrypted image has a random-like behavior.
Authors: Hua Qian Yang, Chang Jiu Pu, Fei Hu, Tao Peng
Abstract: In the paper, a novel combined image encryption and compression scheme is proposed. It performs encryption before compression. Making use of the properties of discrete wavelet transform (DWT) and Set Partitioning in Hierarchical Trees (SPIHT) coding, confusion is restricted to the interior of single subband image itself and so image details are retained. The proposed algorithm possesses a good visual quality of the reconstructed image and a high encryption speed.
Authors: Jian Hua Song, Yong Zhu
Abstract: Digital watermarking is an efficient method for the intellectual property protection and identification. A digital watermarking method by double encryption based on Arnold and chaos in DCT domain was proposed in this paper. First, the digital watermarking was transformed by Arnold scrambling, and then the watermarking was encrypted by chaos system again, so it made the watermarking get double encryption. The encrypted watermarking was embedded into the parts of low-frequency coefficients. The experimental results show that the algorithm is effective and robust for several attacks such as common noise, filtering, cropping and JPEG compression, as well as its good security.
Authors: Qiu Ling Zhao, Li Yang
Abstract: A passive-walking of a double-legs planar Robot is considered. The dynamic equation of the system walking down a shallow slope, powered only by gravity is established according to Lagrange method. After the equation was transferred to a dimensionless one, it shows the motion is depended not only on the free parameter, the ramp slope γ, but also on the ratio of m/M, m is mass of the foot of the model and M is the mass of the hip as well; The analytic calculations show that at the identical ramp slope γ, the whole moving has different phases: stable period walking and chaos with the increasing of m/M. Its phase portraits and graph of step time interval show the influence to the motion because of the ratio of m/M.
Authors: Hong Mei Ni, Zhian Yi, Jin Yue Liu
Abstract: Chaos is a non-linear phenomenon that widely exists in the nature. Due to the ease of implementation and its special ability to avoid being trapped in local optima, chaos has been a novel optimization technique and chaos-based searching algorithms have aroused intense interests. Many real world optimization problems are dynamic in which global optimum and local optima change over time. Particle swarm optimization has performed well to find and track optima in static environments. When the particle swarm optimization (PSO) algorithm is used in dynamic multi-objective problems, there exist some problems, such as easily falling into prematurely, having slow convergence rate and so on. To solve above problems, a hybrid PSO algorithm based on chaos algorithm is brought forward. The hybrid PSO algorithm not only has the efficient parallelism but also increases the diversity of population because of the chaos algorithm. The simulation result shows that the new algorithm is prior to traditional PSO algorithm, having stronger adaptability and convergence, solving better the question on moving peaks benchmark.
Authors: Wei Jian Ren, Yuan Jun Qi, Wei Lv, Cheng Da Li
Abstract: According to the phenomenon of falling into local optimum during solving large-scale optimization problems and the shortcomings of poor convergence of Immune Genetic Algorithm, a new kind of probability selection method based on the concentration for the genetic operation is presented. Considering the features of chaos optimization method, such like not requiring the solved problems with continuity or differentiability, which is unlike the conventional method, and also with a solving process within a certain range traverse in order to find the global optimal solution, a kind of Chaos Immune Genetic Algorithm based on Logistic map and Hénon map is proposed. Through the application to TSP problem, the results have showed the superior to other algorithms.
Authors: Zoltán Pálmai
Abstract: The common feature of the different forming technologies is that the deformation is concentrated into a relatively narrow shear zone. The behaviour of the material can be defined only by specific material properties, the definition of which is difficult and costly. We have developed a new method for the comparatively simple and cheap definition of these specific material properties based on the well known theory and the sophisticated measuring technology of cutting. To achieve this we have developed our previous dynamic technological model, which is described by evolution and delay differential equations. As an example, in the case of a steel with 13% Cr content T, C555520−≈8.26.2−≈=φεγ, the thermal softening 4410−−≈=sφεγ&&≈κ0.98±0.016 MPa/K, the strain rate sensitivity constant k≈0.034±0.009 and the strain hardening exponent n0.170.005.
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