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  • Open Access


    Efficiency Effect of Obstacle Margin on Line-of-Sight in Wireless Networks

    Murad A. A. Almekhlafi1, Taiseer Abdalla Elfadil Eisa2, Fahd N. Al-Wesabi3,4, Abdelzahir Abdelmaboud5, Manar Ahmed Hamza6,*, Abdelwahed Motwakel6, Ishfaq Yaseen6, Mohammed Rizwanullah6

    CMC-Computers, Materials & Continua, Vol.72, No.1, pp. 227-242, 2022, DOI:10.32604/cmc.2022.024356

    Abstract Line-of-sight clarity and assurance are essential because they are considered the golden rule in wireless network planning, allowing the direct propagation path to connect the transmitter and receiver and retain the strength of the signal to be received. Despite the increasing literature on the line of sight with different scenarios, no comprehensive study focuses on the multiplicity of parameters and basic concepts that must be taken into account when studying such a topic as it affects the results and their accuracy. Therefore, this research aims to find limited values that ensure that the signal reaches the future efficiently and enhances… More >

  • Open Access


    Analysis and Modeling of Propagation in Tunnel at 3.7 and 28 GHz

    Md Abdus Samad1,2, Dong-You Choi1,*

    CMC-Computers, Materials & Continua, Vol.71, No.2, pp. 3127-3143, 2022, DOI:10.32604/cmc.2022.023086

    Abstract In present-day society, train tunnels are extensively used as a means of transportation. Therefore, to ensure safety, streamlined train operations, and uninterrupted internet access inside train tunnels, reliable wave propagation modeling is required. We have experimented and measured wave propagation models in a 1674 m long straight train tunnel in South Korea. The measured path loss and the received signal strength were modeled with the Close-In (CI), Floating intercept (FI), CI model with a frequency-weighted path loss exponent (CIF), and alpha-beta-gamma (ABG) models, where the model parameters were determined using minimum mean square error (MMSE) methods. The measured and the… More >

  • Open Access


    Mass-Stiffness Templates for Cubic Structural Elements

    Carlos A. Felippa*

    CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1209-1241, 2021, DOI:10.32604/cmes.2021.016803

    Abstract This paper considers Lagrangian finite elements for structural dynamics constructed with cubic displacement shape functions. The method of templates is used to investigate the construction of accurate mass-stiffness pairs. This method introduces free parameters that can be adjusted to customize elements according to accuracy and rank-sufficiency criteria. One- and two-dimensional Lagrangian cubic elements with only translational degrees of freedom (DOF) carry two additional nodes on each side, herein called side nodes or SN. Although usually placed at the third-points, the SN location may be adjusted within geometric limits. The adjustment effect is studied in detail using symbolic computations for a… More >

  • Open Access


    Wave Propagation Model in a Human Long Poroelastic Bone under Effect of Magnetic Field and Rotation

    A. M. Abd-Alla1,*, Hanaa Abu-Zinadah2, S. M. Abo-Dahab3, J. Bouslimi4,5, M. Omri6

    CMC-Computers, Materials & Continua, Vol.68, No.2, pp. 1485-1504, 2021, DOI:10.32604/cmc.2021.012586

    Abstract This article is aimed at describing the way rotation and magnetic field affect the propagation of waves in an infinite poroelastic cylindrical bone. It offers a solution with an exact closed form. The authors got and examined numerically the general frequency equation for poroelastic bone. Moreover, they calculated the frequencies of poroelastic bone for different values of the magnetic field and rotation. Unlike the results of previous studies, the authors noticed little frequency dispersion in the wet bone. The proposed model will be applicable to wide-range parametric projects of bone mechanical response. Examining the vibration of surface waves in rotating… More >

  • Open Access


    A New BEM for Fractional Nonlinear Generalized Porothermoelastic Wave Propagation Problems

    Mohamed Abdelsabour Fahmy1,2,*

    CMC-Computers, Materials & Continua, Vol.68, No.1, pp. 59-76, 2021, DOI:10.32604/cmc.2021.015115

    Abstract The main purpose of the current article is to develop a novel boundary element model for solving fractional-order nonlinear generalized porothermoelastic wave propagation problems in the context of temperature-dependent functionally graded anisotropic (FGA) structures. The system of governing equations of the considered problem is extremely very difficult or impossible to solve analytically due to nonlinearity, fractional order diffusion and strongly anisotropic mechanical and physical properties of considered porous structures. Therefore, an efficient boundary element method (BEM) has been proposed to overcome this difficulty, where, the nonlinear terms were treated using the Kirchhoff transformation and the domain integrals were treated using… More >

  • Open Access


    Rayleigh Waves Propagation in an Infinite Rotating Thermoelastic Cylinder

    A. M. Farhan1,2,*

    CMC-Computers, Materials & Continua, Vol.67, No.2, pp. 2515-2525, 2021, DOI:10.32604/cmc.2021.014255

    Abstract In this paper, we investigated the inuence of rotating half-space on the propagation of Rayleigh waves in a homogeneous isotropic, generalized thermo-elastic body, subject to the boundary conditions that the surface is traction free. In addition, it is subject to insulating thermal conduction. A general solution is obtained by using Lame’ potential’s and Hankel transform. The dispersion equations has been derived separately for two types of Rayleigh wave propagation properties by solving the equations of motion with appropriate boundary conditions. It is observed that the rotation, frequency and r exert some influence in the homogeneous isotropic medium due to propagation… More >

  • Open Access


    Propagation of a Thermoelastic Wave in a Half-Space of a Homogeneous Isotropic Material Subjected to the Effect of Rotation and Initial Stress

    Fatima Bayones1, Abdelmooty Abd-Alla2, *, Raghad Alfatta3, Hoda Al-Nefaie3

    CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 551-567, 2020, DOI:10.32604/cmc.2020.08420

    Abstract The propagation of thermoelastic waves in a homogeneous, isotropic elastic semi-infinite space is subjected to rotation and initial stress, which is at temperature T0 - initially, and whose boundary surface is subjected to heat source and load moving with finite velocity. Temperature and stress distribution occurring due to heating or cooling and have been determined using certain boundary conditions. Numerical results have been given and illustrated graphically in each case considered. Comparison is made with the results predicted by the theory of thermoelasticity in the absence of rotation and initial stress. The results indicate that the effect of the rotation… More >

  • Open Access


    On Axisymmetric Longitudinal Wave Propagation in Double-Walled Carbon Nanotubes

    S.D. Akbarov1,2

    CMC-Computers, Materials & Continua, Vol.33, No.1, pp. 63-85, 2013, DOI:10.3970/cmc.2013.033.063

    Abstract An attempt is made into the investigation of longitudinal axisymmetric wave propagation in the DWCNT with the use of the exact equations of motion of the linear theory of elastodynamics. The DWCNT is modeled as concentricallynested two circular hollow cylinders between which there is free space. The difference in the radial displacements of these cylinders is coupled with the van der Waals forces and it is assumed that full slipping conditions occur on the inner surface of the outer tube and on the outer surface of the inner tube. Numerical results on the influence of the problem parameters such as… More >

  • Open Access


    GPR Wave Propagation Model in a Complex Geoelectric Structure Using Conformal First-Order Symplectic Euler Algorithm

    Man Yang1,2,3, Hongyuan Fang1,2,3,*, Juan Zhang4, Fuming Wang1,2,3, Jianwei Lei1,2,3, Heyang Jia1,2,3

    CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 793-816, 2019, DOI:10.32604/cmc.2019.06042

    Abstract Possessing advantages such as high computing efficiency and ease of programming, the Symplectic Euler algorithm can be applied to construct a ground-penetrating radar (GPR) wave propagation numerical model for complex geoelectric structures. However, the Symplectic Euler algorithm is still a difference algorithm, and for a complicated boundary, ladder grids are needed to perform an approximation process, which results in a certain amount of error. Further, grids that are too dense will seriously decrease computing efficiency. This paper proposes a conformal Symplectic Euler algorithm based on the conformal grid technique, amends the electric/magnetic field-updating equations of the Symplectic Euler algorithm by… More >

  • Open Access


    A Discrete Model for the High Frequency Elastic Wave Examination on Biological Tissue

    Jun Liu1, Mauro Ferrari1

    CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 421-430, 2003, DOI:10.3970/cmes.2003.004.421

    Abstract A microstructure-accounting mechanical field theory approach is applied to the problem of reflection from a granular thin layer embedded between two solid substrates to study the direct relationship of the micro-structural parameters and the overall reflection coefficients of the thin layer. The exact solution for plane wave reflection coefficients is derived under the new theoretical framework giving quantitative relations between the macroscopic reflection coefficients and a set of micro structural/physical parameters including particle size and micromoduli. The model was analyzed using averaged material properties of biological tissue for the granular thin layer. It was demonstrated that changes in micro-level physical… More >

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