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Controlling chaos in mixed TCP and UDP model

Journal of Computational Information Systems 2013年第23期9卷 9341-9346页

作者： Ding, Dawei Qiu, Sen Guo, Fan Zhang, Kun Xu, Xianfan Key Laboratory of Intelligent Computing and Signal Processing of Ministry of Education Anhui University Hefei 230039 China School of Electronics and Information Engineering Anhui University Hefei 230601 China

In this paper, a discrete time model of the mixed TCP and UDP connection with the RED is introduced. We use this one order discrete-time model to explain the instability, bifurcation and chaotic behaviors of the system. Then a time delayed feedback control approaches is applied to control the system in order to stabilize the chaotic behavior of average queue size. From numerical simulation it is concluded that the chaotic orbit can be stabilize to a fixed point when feedback parameter is properly chosen. Copyright © 2013 Binary Information Press.

关键词： Transmission control protocol

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Non-fragile Observer Design for Fractional-order One-sided Lipschitz Nonlinear Systems

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International Journal of Automation and computing 2013年第4期10卷 296-302页

作者： Yong-Hong Lan Wen-Jie Li Yan Zhou Yi-Ping Luo School of Information Engineering Xiangtan University Key Laboratory of Intelligent Computing and Information Processing of Ministry of Education Xiangtan University Institute of Intelligent Control Hunan Institute of Engineering

This paper is concerned with the problem of the full-order observer design for a class of fractional-order Lipschitz nonlinear systems. By introducing a continuous frequency distributed equivalent model and using an indirect Lyapunov approach, the sufficient condition for asymptotic stability of the full-order observer error dynamic system is presented. The stability condition is obtained in terms of LMI, which is less conservative than the existing one. A numerical example demonstrates the validity of this approach.

关键词： Fractional-order nonlinear system observer design indirect Lyapunov approach linear matrix inequality （LMI）.

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A high order composite scheme for the second order elliptic problem with nonlocal boundary and its fast algorithm

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Applied Mathematics and Computation 2014年 227卷 212-221页

作者： Cunyun Nie Shi Shu Haiyuan Yu Qianjiang An Department of Mathematics and Physics The Hunan Institution of Engineering Xiangtan City Hunan 411104 China Hunan Key Laboratory for Computation & Simulation in Science and Engineering Key Laboratory of Intelligent Computing & Information Processing of Ministry of Education Xiangtan University Hunan 411105 China Department of Mathematics The Institute of Tongren Guizhou 554300 China

The elliptic problem with nonlocal boundary condition is widely applied in the field of science and engineering. Firstly, we construct a linear finite element scheme for the nonlocal boundary problem, and derive the optimal L 2 error estimate. Then, based on the quadratic finite element and the extrapolation linear finite element methods, we present a composite scheme, and prove that it is convergent order three. Furthermore, we design an upper triangular preconditioning algorithm for the linear finite element discrete system. Finally, numerical results not only validate that the new algorithm is efficient, but also show that the new scheme is convergent order three, furthermore order four on uniform grids.

关键词： The elliptic problem with nonlocal boundary condition The finite element method An upper triangular preconditioner Algebraic multigrid method

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Topological properties and fractal analysis of a recurrence network constructed from fractional Brownian motions

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Physical Review E 2014年第3期89卷 032814-032814页

作者： Jin-Long Liu Zu-Guo Yu Vo Anh Hunan Key Laboratory for Computation and Simulation in Science and Engineering and Key Laboratory of Intelligent Computing and Information Processing of Ministry of Education Xiangtan University Xiangtan Hunan 411105 China School of Mathematical Sciences Queensland University of Technology GPO Box 2434 Brisbane Q4001 Australia

Many studies have shown that we can gain additional information on time series by investigating their accompanying complex networks. In this work, we investigate the fundamental topological and fractal properties of recurrence networks constructed from fractional Brownian motions (FBMs). First, our results indicate that the constructed recurrence networks have exponential degree distributions; the average degree exponent 〈λ〉 increases first and then decreases with the increase of Hurst index H of the associated FBMs; the relationship between H and 〈λ〉 can be represented by a cubic polynomial function. We next focus on the motif rank distribution of recurrence networks, so that we can better understand networks at the local structure level. We find the interesting superfamily phenomenon, i.e., the recurrence networks with the same motif rank pattern being grouped into two superfamilies. Last, we numerically analyze the fractal and multifractal properties of recurrence networks. We find that the average fractal dimension 〈dB〉 of recurrence networks decreases with the Hurst index H of the associated FBMs, and their dependence approximately satisfies the linear formula 〈dB〉≈2−H, which means that the fractal dimension of the associated recurrence network is close to that of the graph of the FBM. Moreover, our numerical results of multifractal analysis show that the multifractality exists in these recurrence networks, and the multifractality of these networks becomes stronger at first and then weaker when the Hurst index of the associated time series becomes larger from 0.4 to 0.95. In particular, the recurrence network with the Hurst index H=0.5 possesses the strongest multifractality. In addition, the dependence relationships of the average information dimension 〈D(1)〉 and the average correlation dimension 〈D(2)〉 on the Hurst index H can also be fitted well with linear functions. Our results strongly suggest that the recurrence network inherits the basic characteristic

关键词： TOPOLOGICAL property FRACTAL analysis BROWNIAN motion CORRELATION (Statistics) RECURSIVE sequences (Mathematics) COMPUTER networks

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Control of Hopf bifurcation in Internet congestion control model via time-delayed feedback control

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Information Technology Journal 2013年第18期12卷 4493-4497页

作者： Xu, Xian-Fan Fan, Guo Ding, Da-Wei Yi, Liu Han, Liu-Jun School of Electronics and Information Engineering Anhui University 230601 Hefei China Key Laboratory of Intelligent Computing and Signal Processing Ministry of Education Anhui University 230039 Hefei China

In this study, we are concerned with controlling Hopf bifurcation in a dual model of Internet congestion control algorithms. The stability of this system depends on a communication delay parameter, and Hopf bifurcation occurs when the communication delay passes through a critical value. Comparing with previous work, a time-delayed feedback method is proposed to postpone the onset of undesired Hopf bifurcation and improve stability of the dual model. Theoretical analysis and numerical simulation are provided to verify the effectiveness of our method. © 2013 Asian Network for Scientific Information.

关键词： Hopf bifurcation

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Crank-Nicolson difference scheme for the coupled nonlinear Schrödinger equations with the Riesz space fractional derivative

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Journal of Computational Physics 2013年 242卷 670-681页

作者： Wang, Dongling Xiao, Aiguo Yang, Wei Hunan Key Laboratory for Computation and Simulation in Science and Engineering Key Laboratory of Intelligent Computing and Information Processing of Ministry of Education Xiangtan University Xiangtan Hunan 411105 China

In this paper, the Crank-Nicolson (CN) difference scheme for the coupled nonlinear Schrödinger equations with the Riesz space fractional derivative is studied. The existence of this difference solution is proved by the Brouwer fixed point theorem. The stability and convergence of the CN scheme are discussed in the L2 norm. When the fractional order is two, all those results are in accord with the difference scheme developed for the classical non-fractional coupled nonlinear Schrödinger equations. Some numerical examples are also presented. © 2013 Elsevier Inc.

关键词： Nonlinear equations

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Multifractal analysis of weighted networks by a modified sandbox algorithm

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Scientific reports 2015年第1期5卷 17628页

作者： Yu-Qin Song Jin-Long Liu Zu-Guo Yu Bao-Gen Li Hunan Key Laboratory for Computation and Simulation in Science and Engineering and Key Laboratory of Intelligent Computing and Information Processing of Ministry of Education Xiangtan University Xiangtan Hunan 411105 China. College of Science Hunan University of technology Zhuzhou Hunan 412007 China. School of Mathematical Sciences Queensland University of Technology Brisbane Q4001 Australia.

Complex networks have attracted growing attention in many fields. As a generalization of fractal analysis, multifractal analysis (MFA) is a useful way to systematically describe the spatial heterogeneity of both theoretical and experimental fractal patterns. Some algorithms for MFA of unweighted complex networks have been proposed in the past a few years, including the sandbox (SB) algorithm recently employed by our group. In this paper, a modified SB algorithm (we call it SBw algorithm) is proposed for MFA of weighted networks. First, we use the SBw algorithm to study the multifractal property of two families of weighted fractal networks (WFNs): "Sierpinski" WFNs and "Cantor dust" WFNs. We also discuss how the fractal dimension and generalized fractal dimensions change with the edge-weights of the WFN. From the comparison between the theoretical and numerical fractal dimensions of these networks, we can find that the proposed SBw algorithm is efficient and feasible for MFA of weighted networks. Then, we apply the SBw algorithm to study multifractal properties of some real weighted networks - collaboration networks. It is found that the multifractality exists in these weighted networks, and is affected by their edge-weights.

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Characterizing strong light-atom interaction by a self-consistent solution to Maxwell-Schrödinger equations

Characterizing strong light-atom interaction by a self-consi...

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USNC-URSI Radio Science Meeting (Joint with AP-S Symposium)

作者： Jing Shen Wei E. I. Sha Xianliang Wu Department of Physics and Electronic Engineering Hefei Normal University Hefei China Department of Electrical and Electronic Engineering The University of Hong Kong Hong Kong Key Laboratory of Intelligent Computing and Signal Processing Anhui University Hefei China

Summary form only given. Strong light-atom interaction is at the heart of atomic, molecular and optical physics; and is also important to quantum optics, quantum computing, nuclear magnetic resonance and laser. When an atom (or two-level system) is illuminated by a coherent beam of photons, it will cyclically absorb photons and re-emit them by stimulated emission, which is called Rabi oscillation. Here we developed a semiclassical framework to model the phenomenon via a self-consistent solution to Maxwell-Schrödinger equations. Different from Maxwell-Bloch equations, the wave function of the atom replacing for the density matrix nonlinearly interacts with the magnetic vector potential under coulomb gauge condition. A well-posed time evolution system derived from light-atom Hamiltonian is numerically solved by finite-difference time-domain method. The developed semiclassical Maxwell-Schrödinger framework could be generalized to model light-exciton interaction in semiconductor nanostructures.

关键词： Mathematical model Equations Educational institutions Vectors Physics Roads Atom optics

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Video tracking of human with occlusion based on MeanShift and Kalman filter

Video tracking of human with occlusion based on MeanShift an...

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2013 International Conference on Vehicle and Mechanical Engineering and Information Technology, VMEIT 2013

作者： Yuan, Bao Hong Zhang, De Xiang Fu, Kui Zhang, Ling Jun Key Lab. of Intelligent Computing and Signal Processing Ministry of Education Anhui University Hefei China

ISBN: (纸本)9783037858202

In order to accomplish tracking of moving objects requirements, and overcome the defect of occlusion in the process of tracking moving object, this paper presents a method which uses a combination of MeanShift and Kalman filter algorithm. MeanShift object tracking algorithm uses a histogram to describe the color characteristics of an object, and search the location of an image region that the color histogram is closest to the histogram of the object. Histogram similarity is defined in terms of the Bhattacharya coefficient. When the moving object is a large area blocked, the future state of moving object is estimated by Kalman filter. Experimental results verify that the proposed algorithm achieves efficient tracking of moving objects under the confusing situations. © (2013) Trans Tech Publications, Switzerland.

关键词： Kalman filters

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A study on turbo code performance based on AWGN channel

A study on turbo code performance based on AWGN channel

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2013 International Conference on Precision Mechanical Instruments and Measurement Technology, ICPMIMT 2013

作者： Zhu, Peng Zhu, Jun Liu, Xiang Key Laboratory of Intelligent Computing and Signal Processing of Ministry of Education Anhui University No.3 Feixi Rd Hefei 230039 China

Turbo codes have a wide range of applications in 3G mobile communications, deep-sea communications, satellite communications and other power constrained fields. In the paper, the Turbo Code Decoding Principle and several major decoding methods are introduced. Simulations of Turbo code performance under different parameters of AWGN channel are made and the effects of the different interleaving length, the number of iterations, and the decoding algorithm to Turbo code performance are also discussed in AWGN channel. Simulation results show that under the same signal-to-noise ratio, the more the number of iterations is, the longer the sequence of information is, and the more excellent decoding algorithm is, the better the performance of Turbo codes is. © 2013 Trans Tech Publications Ltd, Switzerland.

关键词： Bit error rate

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