M. F. Elettreby^{1, 2, *}, Tamer Nabil^{1, 3}, A. Khawagi⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.3, pp. 907-921, 2020, DOI:10.32604/cmes.2020.08664 - 01 March 2020

Abstract In this paper, a discrete Lotka-Volterra predator-prey model is proposed that considers mixed functional responses of Holling types I and III. The equilibrium points of the model are obtained, and their stability is tested. The dynamical behavior of this model is studied according to the change of the control parameters. We find that the complex dynamical behavior extends from a stable state to chaotic attractors. Finally, the analytical results are clarified by some numerical simulations. More >

Yubing Li^a , Mo Yang^a,*, Jian Li^b , Zhiyun Wang^a

Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-8, 2019, DOI:10.5098/hmt.13.11

Abstract Thermalsolutal convection induced by mass and heat source in horizontal cavity is investigated numerically based on SIMPLE algorithm with QUICK scheme. The high-concentration heat source is placed in the square cavity, and the cavity wall is low temperature and low concentration. The smoke is used as the diffusion medium, and the flow field, temperature and concentration of the fluid under different Rayleigh number, buoyancy ratio Nc, Soret numbers and Dufour numbers are analyzed systematically. Parameter study demonstrates that heat and mass transfer of thermosolutal convection are enhanced with increasing Rayleigh number or buoyancy ratio, and More >

Bin Lu¹, Fenlin Liu¹, Xin Ge^1,*, Zhenyu Li²

CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 687-699, 2019, DOI:10.32604/cmc.2019.05633

Abstract Due to the characteristics of chaotic systems, different cryptosystems based on chaos have been proposed to satisfy the security of multimedia data. A plain image-related chaotic algorithm is proposed by Luo et al. with high speed and efficiency. Security weaknesses of the cryptosystem are studied in this paper. It is found that the important secret key information is leaked because an important parameter can be obtained after an inverse operation in the last step of the cryptosystems without secret key. Meanwhile, the value zero is processed improperly in quantification algorithm. Based on the weaknesses, chosen More >

Shaojiang Zhong^{1, *}

CMC-Computers, Materials & Continua, Vol.60, No.2, pp. 465-479, 2019, DOI:10.32604/cmc.2019.05853

Abstract Based on the three-dimensional classic Chua circuit, a nonlinear circuit containing two flux-control memristors is designed. Due to the difference in the design of the characteristic equation of the two magnetron memristors, their position form a symmetrical structure with respect to the capacitor. The existence of chaotic properties is proved by analyzing the stability of the system, including Lyapunov exponent, equilibrium point, eigenvalue, Poincare map, power spectrum, bifurcation diagram et al. Theoretical analysis and numerical calculation show that this heterogeneous memristive model is a hyperchaotic five-dimensional nonlinear dynamical system and has a strong chaotic behavior. More >

Na Lin¹, Jiacheng Tang¹, Xianwei Li^2,3, Liang Zhao^1,*

CMC-Computers, Materials & Continua, Vol.61, No.1, pp. 323-344, 2019, DOI:10.32604/cmc.2019.05674

Abstract Path planning algorithm is the key point to UAV path planning scenario. Many traditional path planning methods still suffer from low convergence rate and insufficient robustness. In this paper, three main methods are contributed to solving these problems. First, the improved artificial potential field (APF) method is adopted to accelerate the convergence process of the bat’s position update. Second, the optimal success rate strategy is proposed to improve the adaptive inertia weight of bat algorithm. Third chaos strategy is proposed to avoid falling into a local optimum. Compared with standard APF and chaos strategy in… More >

Dongping Tian^a,b

Intelligent Automation & Soft Computing, Vol.24, No.2, pp. 331-342, 2018, DOI:10.1080/10798587.2017.1293881

Abstract Particle swarm optimization (PSO) is a population based swarm intelligence algorithm that has been deeply studied and widely applied to a variety of problems. However, it is easily trapped into the local optima and premature convergence appears when solving complex multimodal problems. To address these issues, we present a new particle swarm optimization by introducing chaotic maps (Tent and Logistic) and Gaussian mutation mechanism as well as a local re-initialization strategy into the standard PSO algorithm. On one hand, the chaotic map is utilized to generate uniformly distributed particles to improve the quality of the… More >

Mengchu Tian¹, Yuming Bo¹, Zhimin Chen^2,3, Panlong Wu¹, Gaopeng Zhao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.5, pp. 285-301, 2015, DOI:10.3970/cmes.2015.108.285

Abstract Particle filter based on particle swarm optimization algorithm is not precise enough and easily trapping in local optimum, it is difficult to satisfy the requirement of advanced integrated navigation system. To solve these problems, an improved adaptive particle filter based on chaos particle swarm was proposed and used in GPS/INS integrated navigation system. This algorithm introduced chaos sequence to update the weight and threshold, which could improve the quality of samples and reduce the local optimization and enhance the global searching ability. In addition, the avoid factor was set which made the particles be away More >

H.E. Dillon, A.F. Emery^†, A.M. Mescher, O. Sprenger, S.R. Edwards

Frontiers in Heat and Mass Transfer, Vol.2, No.2, pp. 1-14, 2011, DOI:10.5098/hmt.v2.2.3002

Abstract The stability of free convection in an annulus is governed by the boundary conditions on the inner and outer walls of the annulus and the upper and lower boundaries. This paper explores the effect of free convection on the inner surface of the annulus, where the boundary conditions for the outer wall and the upper and lower boundaries are controlled. The temperature is measured in the center of the air cavity and just below the surface of the inner annular boundary. Experimental results are shown for a radius ratio of 0.40, aspect ratio of 20.7. More >

S.J. Zhu, Q.H Zeng, J.J Lou, Q.W He

The International Conference on Computational & Experimental Engineering and Sciences, Vol.18, No.2, pp. 43-44, 2011, DOI:10.3970/icces.2011.018.043

Abstract Line spectra are the most visible signs of the ships' radiated noise spectrum. The potential of chaotifying vibration isolation systems to reduce line spectra and improve its capability of concealment have been recently reported. Basically, as the existing isolation system design is based on linear theory, it is difficult to produce the nonlinear chaotic motion; and if the vibration isolation system(VIS) is designed directly using the nonlinear theory, it is also difficult to produce the chaotic motion because of the difficulties in accurate calculation of vibration isolation device parameters. In this paper, a controller design More >

J.L. Sereno¹, J.C.F. Pereira¹

CMES-Computer Modeling in Engineering & Sciences, Vol.73, No.1, pp. 23-44, 2011, DOI:10.3970/cmes.2011.073.023

Abstract The evolution of a two-dimensional vortex pair in ground effect was studied under the influence of random initial inputs comprising vortex strength (circulation) or initial vortex position. The paper addresses the questions of how do variations and uncertainties of initial conditions translate to the variability of vortex pair evolution. The stochastic solutions were obtained recurring to the Polynomial Chaos Expansion method of random processes applied to the Navier-Stokes equations for a laminar flow. The method quantifies the extent, dependence and propagation of uncertainty through the model system and, in particular, a methodology for the calculation More >