Zhiguo Qu^1,*, Shengyao Wu², Wenjie Liu¹, Xiaojun Wang³

CMC-Computers, Materials & Continua, Vol.59, No.2, pp. 607-624, 2019, DOI:10.32604/cmc.2019.02656

Abstract In the field of quantum communication, quantum steganography is an important branch of quantum information hiding. In a realistic quantum communication system, quantum noises are unavoidable and will seriously impact the safety and reliability of the quantum steganographic system. Therefore, it is very important to analyze the influence of noise on the quantum steganography protocol and how to reduce the effect of noise. This paper takes the quantum steganography protocol proposed in 2010 as an example to analyze the effects of noises on information qubits and secret message qubits in the four primary quantum noise environments. The results show that… More >

Liu Jianfei^1,2, Sun Shuli^1,3, Wang Dachuan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.14, No.1, pp. 31-44, 2006, DOI:10.3970/cmes.2006.014.031

Abstract Local transformation, or topological re-connection, is one of effective procedures of mesh improvement method, especially in three-dimensional situation. The commonly used local transformations for tetrahedral mesh involve changing in mesh topology (i.e. node-element connectivity relationship) within a relatively small region composed of several tetrahedra, such as 2-3 flip, 3-2 flip, 2-2 flip, 4-4 flip, etc. Although these local transformations are easy to implement and effective in removing poorly-shaped tetrahedra, it is still possible to improve the quality of mesh further by expanding the space of transformation region. In this paper, the concept of optimal tetrahedralization for small polyhedron and corresponding… More >

T. Nakamura¹, R. Kobyashi¹, S. Ogata¹

CMES-Computer Modeling in Engineering & Sciences, Vol.73, No.4, pp. 357-386, 2011, DOI:10.3970/cmes.2011.073.357

Abstract The coarse-grained particle (CGP) method has been proposed to coarse-grain a crystalline system of atoms to meso-scale. In the method, virtual particles are distributed in the system, and the inter-particle interaction is calculated through the constrained statistical ensemble average of the atomic Hamiltonian at a given temperature. For simplicity, however, the harmonic approximation has been used for the inter-atomic interaction and hence anharmonicity at finite temperatures has been ignored. We improve the former CGP method to incorporate the anharmonicity of atomic system at finite temperatures into the inter-particle interaction. Also the divide-and-conquer strategy is applied to calculate the inter-particle interaction… More >

R. Djebali¹, M. El Ganaoui²

CMES-Computer Modeling in Engineering & Sciences, Vol.71, No.3, pp. 179-202, 2011, DOI:10.3970/cmes.2011.071.179

Abstract The Lattice Boltzmann method (LBM) became, today, a powerful tool for simulating fluid flows. Its improvements for different applications and configurations offers more flexibility and results in several schemes such as in presence of external/internal forcing term. However, we look for the suitable model that gives correct informations, matches the hydrodynamic equations and preserves some features like coding easily, preserving computational cost, stability and accuracy. In the present work, high order incompressible models and equilibrium distribution functions for the advection-diffusion equations are analyzed. Boundary conditions, acceleration, stability and preconditioning with initial fields are underlined which permit to rigorously selecting two… More >

Daoming Shen¹, Hua Si^1,*, Jinhong Xia¹, Shunqun Li²

FDMP-Fluid Dynamics & Materials Processing, Vol.15, No.1, pp. 63-76, 2019, DOI:10.32604/fdmp.2019.04799

Abstract The correct determination of thermal parameters, such as thermal conductivity and specific heat of soil during freezing, is the most important and basic problem for the construction of an appropriate freezing method. In this study, a calculation model of three stages of soil temperature was established. At the unfrozen and frozen stages, the specific temperatures of dry soil, water, and ice are known. According to the principle of superposition, a calculation model of unfrozen and frozen soils can be established. Informed by a laboratory experiment, the latent heat of the adjacent zone was calculated for the freezing stage based on… More >

A. Khourchafi¹, M. El Alami^2,3, M. Najam², M. Belhaq⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.8, No.3, pp. 323-338, 2012, DOI:10.3970/fdmp.2012.008.323

Abstract A spectral radiation study has been carried out in the framework of a statistical narrow-band model based on an inverse-tailed exponential law and the socalled P1 approximation. This new spectral formulation, which may be also regarded as a grey band formulation with a local absorption coefficient, leads to two implementation methods: a non correlated form in which the averaged formulation of the P1 approximation does not take into account the correlation between fundamental quantities and a pseudo-correlated variant consisting basically of a technique for improving the anisotropy of the radiative intensity. Real gases (H₂O, CO₂) are considered. The resulting tests… More >

Mark Sussman¹, Mitsuhiro Ohta²

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.1, pp. 21-36, 2007, DOI:10.3970/fdmp.2007.003.021

Abstract In this paper, we describe new techniques for numerically approximating two-phase flows. Specifically, we present new techniques for treating the viscosity and surface tension terms that appear in the Navier-Stokes equations for incompressible two-phase flow. Our resulting numerical method has the property that results computed using our two-phase algorithm approach the corresponding "one-phase'' algorithm in the limit of zero gas density/viscosity; i.e. the two-phase results approach the one-phase free-boundary results in the limit that the gas is assumed to become a uniform pressure void. By grid convergence checks and comparison with previous experimental data, we shall demonstrate the advantages of… More >

Jifeng Zhong^1,*, Zhihao Liu^2,3,*, Juan Xu⁴

CMC-Computers, Materials & Continua, Vol.57, No.3, pp. 621-633, 2018, DOI:10.32604/cmc.2018.03706

Abstract The controlled quantum secure direct communication (CQSDC) with authentication protocol based on four particle cluster states via quantum one-time pad and local unitary operations is cryptanalyzed. It is found that there are some serious security issues in this protocol. An eavesdropper (Eve) can eavesdrop on some information of the identity strings of the receiver and the controller without being detected by the selective-CNOT-operation (SCNO) attack. By the same attack, Eve can also steal some information of the secret message that the sender transmits. In addition, the receiver can take the same kind of attack to eavesdrop on some information of… More >

CMC-Computers, Materials & Continua, Vol.47, No.3, pp. 179-201, 2015, DOI:10.3970/cmc.2015.047.179

Abstract Discontinuous smoothed particle hydrodynamics (DSPH) method based on traditional SPH method, which can be used to simulate discontinuous physics problems near interface or boundary. Previous works showed that DSPH method has a good application prospect [Xu et al, 2013], but further verification and improvement are demanded. In this paper, we investigate the accuracy of DSPH method by some numerical models. Moreover, to improve the accuracy of DSPH method, first order and second order multidimensional RDSPH methods are proposed by following the idea of restoring particle consistency in SPH (RSPH) method which has shown good results in the improvement of particle… More >