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  • Open Access

    ARTICLE

    Particle Swarm Optimization with Chaos-based Initialization for Numerical Optimization

    Dongping Tiana,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 >

  • Open Access

    ARTICLE

    A Novel Robust Watermarking Algorithm for Encrypted Medical Image Based on DTCWT-DCT and Chaotic Map

    Jing Liu1,5, Jingbing Li1,*, Jieren Cheng1, Jixin Ma2, Naveed Sadiq3, Baoru Han4, Qiang Geng5, Yang Ai5

    CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 889-910, 2019, DOI:10.32604/cmc.2019.06034

    Abstract In order to solve the problem of patient information security protection in medical images, whilst also taking into consideration the unchangeable particularity of medical images to the lesion area and the need for medical images themselves to be protected, a novel robust watermarking algorithm for encrypted medical images based on dual-tree complex wavelet transform and discrete cosine transform (DTCWT-DCT) and chaotic map is proposed in this paper. First, DTCWT-DCT transformation was performed on medical images, and dot product was per-formed in relation to the transformation matrix and logistic map. Inverse transformation was undertaken to obtain… More >

  • Open Access

    ARTICLE

    Cryptanalysis and Improvement of a Chaotic Map-Control-Based and the Plain Image-Related Cryptosystem

    Bin Lu1, Fenlin Liu1, Xin Ge1,*, 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 >

  • Open Access

    ABSTRACT

    Chaotic Mixing in a Microfluidic Device

    Chih-Chang Chang, Ruey-Jen Yang1

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.10, No.2, pp. 77-86, 2009, DOI:10.3970/icces.2009.010.077

    Abstract This paper presents a theoretical investigation into chaotic mixing in low Reynolds number electro-osmotic flows. In this mixing system, the primary flow is the plug-like electro-osmotic flow contributed by the permanent surface charge at the wall, and the secondary electro-osmotic flows (or electro-osmotic recirculating rolls) contributed by the field-effect-induced surface charge act as the perturbed flow. By time-periodic switching two different secondary electro-osmotic flows, it makes streamlines to cross at successive intervals and results in chaotic mixing. Dynamic system techniques such as Poincaré map and finite-time Lyapunov exponent analyses are employed to describe the behaviors More >

  • Open Access

    ARTICLE

    An Effective Approach of Secured Medical Image Transmission Using Encryption Method

    Ranu Gupta1,3,*, Rahul Pachauri2,3, Ashutosh Kumar Singh1,4

    Molecular & Cellular Biomechanics, Vol.15, No.2, pp. 63-83, 2018, DOI:10.3970/mcb.2018.00114

    Abstract Various chaos-based image encryption schemes have been proposed in last few years. The proposed image encryption method uses chaotic map. The encryption is done by using 256 bit long external secret key. The initial condition for the chaotic mapping is evaluated by the use of external secret key along with the mapping function. Besides that, the proposed method is made more robust by applying multiple operations to the pixels of the image depending on the outcome of the calculation of the logistic map. Moreover, block shuffling of the image and modifying the secret key after More >

  • Open Access

    ARTICLE

    Machining Parameters Optimization of Multi-Pass Face Milling Using a Chaotic Imperialist Competitive Algorithm with an Efficient Constraint-Handling Mechanism

    Yang Yang1, *

    CMES-Computer Modeling in Engineering & Sciences, Vol.116, No.3, pp. 365-389, 2018, DOI:10.31614/cmes.2018.03847

    Abstract The selection of machining parameters directly affects the production time, quality, cost, and other process performance measures for multi-pass milling. Optimization of machining parameters is of great significance. However, it is a nonlinear constrained optimization problem, which is very difficult to obtain satisfactory solutions by traditional optimization methods. A new optimization technique combined chaotic operator and imperialist competitive algorithm (ICA) is proposed to solve this problem. The ICA simulates the competition between the empires. It is a population-based meta-heuristic algorithm for unconstrained optimization problems. Imperialist development operator based on chaotic sequence is introduced to improve… More >

  • Open Access

    ARTICLE

    Absolute Stability of Chaotic Asynchronous Multi-Interactions Schemes for Solving ODE

    P. Redou1, L. Gaubert1, G. Desmeulles1, P-A. Béal2, C. Le Gal2, V. Rodin3

    CMES-Computer Modeling in Engineering & Sciences, Vol.70, No.1, pp. 11-40, 2010, DOI:10.3970/cmes.2010.070.011

    Abstract Multi Interaction Systems, used in the context of Virtual Reality, are dedicated to real-time interactive simulations. They open the way to the in virtuo experimentation, especially useful in the domain of biochemical kinetics. To this purpose, chaotic and asynchronous scheduling of autonomous processes is based upon desynchronization of phenomena involved in the system. It permits interactivity, especially the capability to add or remove phenomena in the course of a simulation. It provides methods of resolution of ordinary differential systems and partial derivative equations. Proofs of convergence for these methods have been established, but the problem of More >

  • Open Access

    ARTICLE

    A novel MLPG-Finite-Volume Mixed Method for Analyzing Stokesian Flows & Study of a new Vortex Mixing Flow

    Ruben Avila1, Zhidong Han2, Satya N. Atluri3

    CMES-Computer Modeling in Engineering & Sciences, Vol.71, No.4, pp. 363-396, 2011, DOI:10.3970/cmes.2011.071.363

    Abstract The two dimensional steady state Stokes equations are solved by using a novel MLPG-Mixed Finite Volume method, that is based on the independent meshless interpolations of the deviatoric velocity strain tensor, the volumetric velocity strain tensor, the velocity vector and the pressure. The pressure field directly obtained from this method does not suffer from the malady of checker-board patterns. Numerical simulations of the flow field, and trajectories of passive fluid elements in a new complex Stokes flow are also presented. The new flow geometry consists of three coaxial cylinders two of smaller diameter, that steadily More >

  • Open Access

    ARTICLE

    Two-phase flow in complex geometries: A diffuse domain approach

    S. Aland1, J. Lowengrub2, A. Voigt1

    CMES-Computer Modeling in Engineering & Sciences, Vol.57, No.1, pp. 77-108, 2010, DOI:10.3970/cmes.2010.057.077

    Abstract We present a new method for simulating two-phase flows in complex geometries, taking into account contact lines separating immiscible incompressible components. We combine the diffuse domain method for solving PDEs in complex geometries with the diffuse-interface (phase-field) method for simulating multiphase flows. In this approach, the complex geometry is described implicitly by introducing a new phase-field variable, which is a smooth approximation of the characteristic function of the complex domain. The fluid and component concentration equations are reformulated and solved in larger regular domain with the boundary conditions being implicitly modeled using source terms. The… More >

  • Open Access

    ARTICLE

    On the KP Equation with Hysteresis

    Veturia Chiroiu1, Ioan Ursu2, Ligia Munteanu3, Tudor Sireteanu4

    FDMP-Fluid Dynamics & Materials Processing, Vol.8, No.1, pp. 91-106, 2012, DOI:10.3970/fdmp.2011.008.091

    Abstract The Kadomtsev-Petviashvili (KP) equation describes the evolution of nonlinear, long waves of small amplitude with slow dependence on the transverse coordinate. The KP equation coupled with the generalized play operator is studied in this paper in order to explain the dilatonic behavior of the soliton interaction and the generation of huge waves in shallow waters. Hirota bilinear method and results from a nonlinear semigroup theory are applied to simulate the resonant soliton interactions. More >

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