Home / Journals / CMES / Vol.123, No.3, 2020
Table of Content
  • Open Access

    EDITORIAL

    Introduction to the Special Issue on Numerical Methods for Differential and Integral Equations

    Şuayip Yüzbaşı1,*, Kamel Al-Khaled2, Nurcan Baykuş Savaşaneril3, Devendra Kumar4
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 913-915, 2020, DOI:10.32604/cmes.2020.011225
    (This article belongs to this Special Issue: Numerical Methods for Differential and Integral Equations)
    Abstract This article has no abstract. More >

  • Open Access

    ARTICLE

    Crank-Nicolson ADI Galerkin Finite Element Methods for Two Classes of Riesz Space Fractional Partial Differential Equations

    An Chen1, *
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 917-939, 2020, DOI:10.32604/cmes.2020.09224
    (This article belongs to this Special Issue: Numerical Methods for Differential and Integral Equations)
    Abstract In this paper, two classes of Riesz space fractional partial differential equations including space-fractional and space-time-fractional ones are considered. These two models can be regarded as the generalization of the classical wave equation in two space dimensions. Combining with the Crank-Nicolson method in temporal direction, efficient alternating direction implicit Galerkin finite element methods for solving these two fractional models are developed, respectively. The corresponding stability and convergence analysis of the numerical methods are discussed. Numerical results are provided to verify the theoretical analysis. More >

  • Open Access

    ARTICLE

    A Galerkin-Type Fractional Approach for Solutions of Bagley-Torvik Equations

    Şuayip Yüzbaşı1, *, Murat Karaçayır1
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 941-956, 2020, DOI:10.32604/cmes.2020.08938
    (This article belongs to this Special Issue: Numerical Methods for Differential and Integral Equations)
    Abstract In this study, we present a numerical scheme similar to the Galerkin method in order to obtain numerical solutions of the Bagley Torvik equation of fractional order 3/2. In this approach, the approximate solution is assumed to have the form of a polynomial in the variable t = xα , where α is a positive real parameter of our choice. The problem is firstly expressed in vectoral form via substituting the matrix counterparts of the terms present in the equation. After taking inner product of this vector with nonnegative integer powers of t up to a selected positive parameter N,… More >

  • Open Access

    ARTICLE

    RBF Based Localized Method for Solving Nonlinear Partial Integro-Differential Equations

    Marjan Uddin1, *, Najeeb Ullah2, Syed Inayat Ali Shah2
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 957-972, 2020, DOI:10.32604/cmes.2020.08911
    (This article belongs to this Special Issue: Numerical Methods for Differential and Integral Equations)
    Abstract In this work, a numerical scheme is constructed for solving nonlinear parabolictype partial-integro differential equations. The proposed numerical scheme is based on radial basis functions which are local in nature like finite difference numerical schemes. The radial basis functions are used to approximate the derivatives involved and the integral is approximated by equal width integration rule. The resultant differentiation matrices are sparse in nature. After spatial approximation using RBF the partial integro-differential equations reduce to the system of ODEs. Then ODEs system can be solved by various types of ODE solvers. The proposed numerical scheme is tested and compared with… More >

  • Open Access

    ARTICLE

    Bell Polynomial Approach for the Solutions of Fredholm Integro-Differential Equations with Variable Coefficients

    Gökçe Yıldız1, Gültekin Tınaztepe2, *, Mehmet Sezer1
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 973-993, 2020, DOI:10.32604/cmes.2020.09329
    (This article belongs to this Special Issue: Numerical Methods for Differential and Integral Equations)
    Abstract In this article, we approximate the solution of high order linear Fredholm integro-differential equations with a variable coefficient under the initial-boundary conditions by Bell polynomials. Using collocation points and treating the solution as a linear combination of Bell polynomials, the problem is reduced to linear system of equations whose unknown variables are Bell coefficients. The solution to this algebraic system determines the approximate solution. Error estimation of approximate solution is done. Some examples are provided to illustrate the performance of the method. The numerical results are compared with the collocation method based on Legendre polynomials and the other two methods… More >

  • Open Access

    ARTICLE

    The Influence of Entanglements of Net Chains on Phase Transition Temperature of Sensitive Hydrogels in Chemo-Mechanical Coupled Fields

    Tao Li1, Qingsheng Yang1, *, Lianhua Ma2, Xiaojun Zhang2, *
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 995-1014, 2020, DOI:10.32604/cmes.2020.09152
    Abstract Phase transition of hydrogel, which is polymerized by polymer network, can be regarded as the transition of polymer network stability. The stability of the polymer network might be changed when the external environment changed. This change will lead to the transformation of sensitive hydrogels stability, thus phase transition of hydrogel take place. Here, we present a new free density energy function, which considers the non-gaussianity of the polymer network, chains entanglement and functionality of junctions through adding Gent hyplastic model and Edwards-Vilgis slip-link model to Flory-Huggins theory. A program to calculate the phase transition temperature was written based on new… More >

  • Open Access

    ARTICLE

    FP-STE: A Novel Node Failure Prediction Method Based on Spatio-Temporal Feature Extraction in Data Centers

    Yang Yang1,*, Jing Dong1, Chao Fang2, Ping Xie3, Na An3
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1015-1031, 2020, DOI:10.32604/cmes.2020.09404
    Abstract The development of cloud computing and virtualization technology has brought great challenges to the reliability of data center services. Data centers typically contain a large number of compute and storage nodes which may fail and affect the quality of service. Failure prediction is an important means of ensuring service availability. Predicting node failure in cloud-based data centers is challenging because the failure symptoms reflected have complex characteristics, and the distribution imbalance between the failure sample and the normal sample is widespread, resulting in inaccurate failure prediction. Targeting these challenges, this paper proposes a novel failure prediction method FP-STE (Failure Prediction… More >

  • Open Access

    ARTICLE

    T-Splines Based Isogeometric Topology Optimization with Arbitrarily Shaped Design Domains

    Gang Zhao1,2, Jiaming Yang1, Wei Wang1,*, Yang Zhang1, Xiaoxiao Du1, Mayi Guo1
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1033-1059, 2020, DOI:10.32604/cmes.2020.09920
    (This article belongs to this Special Issue: Recent Developments of Isogeometric Analysis and its Applications in Structural Optimization)
    Abstract In this paper, a new isogeometric topology optimization (ITO) method is proposed by using T-splines based isogeometric analysis (IGA). The arbitrarily shaped design domains, directly obtained from CAD, are represented by a single T-spline surface which overcomes the topological limitations of Non-Uniform Rational B-Spline (NURBS). The coefficients correlated with control points are directly used as design variables. Therefore, the T-spline basis functions applied for geometry description and calculation of structural response are simultaneously introduced to represent the density distribution. Several numerical examples show that the proposed approach leads to a coherent workflow to handle design problems of complicated structures. The… More >

  • Open Access

    ARTICLE

    Novel Micromixer with Complex 3D-Shape Inner Units: Design, Simulation and Additive Manufacturing

    Di Wang1, Guangzhao Ye1, Jingming Mai2, Xiaomin Chen1, Yongqiang Yang1,*, Yang Li1,*, Xiaojun Chen1, Jie Chen1
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1061-1077, 2020, DOI:10.32604/cmes.2020.09842
    (This article belongs to this Special Issue: Design & simulation in Additive Manufacturing)
    Abstract In this paper, a novel micromixer with complex 3D-shape inner units was put forward and fabricated by metal Additive Manufacturing (AM). The design of the micromixer combined the constraints of selective laser melting technology and the factors to improve mixing efficiency. Villermaux-Dushman reaction system and Compute Fluid Design (CFD) simulation were conducted to investigate the performance and the mechanism of this novel micromixer to improve mixing efficiency. The research found that the best mixing efficiency of this novel micromixer could be gained when the inner units divided fluid into five pieces with a uniform volume. Compared with a conventional micromixer… More >

  • Open Access

    ARTICLE

    Comparative Investigation of Two Random Medium Models for Concrete Mesostructure

    Shixue Liang1, Zhongshu Xie1, Tiancan Huang2, *
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1079-1103, 2020, DOI:10.32604/cmes.2020.09200
    (This article belongs to this Special Issue: Numerical Modeling and Simulation for Structural Safety and Disaster Mitigation)
    Abstract Concrete is intrinsically endowed with randomness on meso-scale due to the random distribution of aggregates, mortar, etc. In this paper, two random medium models of concrete mesostructure are developed and comparative studies are provided based on random field representation approach. In the first place, concrete is considered as a kind of one-phase random field, where stochastic harmonic function is adopted as the approach to simulate the random field. Secondly, in order to represent the stochastic distribution of the multi-phase of concrete such as aggregates and mortar, two-phase random field based on the Nataf transformation and the Hermite polynomials are introduced.… More >

  • Open Access

    ARTICLE

    Safety Performance of a Precast Concrete Barrier: Numerical Study

    Zishen Li1, Xiangling Gao1, *, Zicheng Tang2
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1105-1129, 2020, DOI:10.32604/cmes.2020.09047
    (This article belongs to this Special Issue: Numerical Modeling and Simulation for Structural Safety and Disaster Mitigation)
    Abstract The numerical simulation for a new type of precast concrete barrier for viaducts is carried out systematically. To obtain an accurate representation of the damage state of the concrete barrier under the impact of a vehicle, a stochastic damage-plasticity model of the concrete is adopted in the finite element model. Meanwhile, a simplified mathematical model of the impact between vehicles and the concrete barrier was established and the input energy was converted to the impact load to facilitate the investigation of the safety performance of the concrete barriers. On this basis, a refined finite element (FE) model of a precast… More >

  • Open Access

    ARTICLE

    Discrete Circular Distributions with Applications to Shared Orthologs of Paired Circular Genomes

    Tomoaki Imoto1, *, Grace S. Shieh2, *, Kunio Shimizu3
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1131-1149, 2020, DOI:10.32604/cmes.2020.08466
    (This article belongs to this Special Issue: Data Science and Modeling in Biology, Health, and Medicine)
    Abstract For structural comparisons of paired prokaryotic genomes, an important topic in synthetic and evolutionary biology, the locations of shared orthologous genes (henceforth orthologs) are observed as binned data. This and other data, e.g., wind directions recorded at monitoring sites and intensive care unit arrival times on the 24-hour clock, are counted in binned circular arcs, thus modeling them by discrete circular distributions (DCDs) is required. We propose a novel method to construct a DCD from a base continuous circular distribution (CCD). The probability mass function is defined to take the normalized values of the probability density function at some pre-fixed… More >

  • Open Access

    ARTICLE

    Robust Remaining Useful Life Estimation Based on an Improved Unscented Kalman Filtering Method

    Shenkun Zhao, Chao Jiang*, Zhe Zhang, Xiangyun Long
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1151-1173, 2020, DOI:10.32604/cmes.2020.08867
    (This article belongs to this Special Issue: Novel Methods for Reliability Evaluation and Optimization of Complex Mechanical Structures)
    Abstract In the Prognostics and Health Management (PHM), remaining useful life (RUL) is very important and utilized to ensure the reliability and safety of the operation of complex mechanical systems. Recently, unscented Kalman filtering (UKF) has been applied widely in the RUL estimation. For a degradation system, the relationship between its monitored measurements and its degradation states is assumed to be nonlinear in the conventional UKF. However, in some special degradation systems, their monitored measurements have a linear relation with their degradation states. For these special problems, it may bring estimation errors to use the UKF method directly. Besides, many uncertain… More >

  • Open Access

    ARTICLE

    Fast Single Image Haze Removal Method for Inhomogeneous Environment Using Variable Scattering Coefficient

    Rashmi Gupta1, Manju Khari1, Vipul Gupta1, Elena Verdú2, Xing Wu3, Enrique Herrera-Viedma4, Rubén González Crespo2,*
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1175-1192, 2020, DOI:10.32604/cmes.2020.010092
    (This article belongs to this Special Issue: Security Enhancement of Image Recognition System in IoT based Smart Cities)
    Abstract The images capture in a bad environment usually loses its fidelity and contrast. As the light rays travel towards its destination they get scattered several times due to the tiny particles of fog and pollutants in the environment, therefore the energy gets lost due to multiple scattering till it arrives its destination, and this degrades the images. So the images taken in bad weather appear in bad quality. Therefore, single image haze removal is quite a bit tough task. Significant research has been done in the haze removal algorithm but in all the techniques, the coefficient of scattering is taken… More >

  • Open Access

    ARTICLE

    A New Method of Roughness Construction and Analysis of Construct Parameters

    Hui Lu, Xinyue Duan, Minghai Xu*, Liang Gong, Bin Ding
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1193-1204, 2020, DOI:10.32604/cmes.2020.08989
    (This article belongs to this Special Issue: Advances in Modeling and Simulation of Complex Heat Transfer and Fluid Flow)
    Abstract In micro-manufacturing, roughness is unavoidable due to the tolerance of micro-machining methods. Roughness in microchannel could have a significant influence on flow and heat transfer since the size of microchannel is very small. In our work, roughness is modeled as a superposition of waves. A simple Fourier series method is proposed to construct the rough surface. With this method, roughness is constructed on the bottom of the rectangular microchannel which has a hydraulic diameter of 0.5 mm. Two important parameters during roughness construction, triangulate size and correlation length are studied under the same relative roughness 1%. Results show that flow… More >

  • Open Access

    ARTICLE

    Modeling Tracer Flow Characteristics in Different Types of Pores: Visualization and Mathematical Modeling

    Tongjing Liu1, 2, *, Weixia Liu3, Pengxiang Diwu4, Gaixing Hu5, 6, Ting Xu1, 7, Yuqi Li2, Zhenjiang You8, Runwei Qiao2, Jia Wang2
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1205-1222, 2020, DOI:10.32604/cmes.2020.08961
    (This article belongs to this Special Issue: Advances in Modeling and Simulation of Complex Heat Transfer and Fluid Flow)
    Abstract Structure of porous media and fluid distribution in rocks can significantly affect the transport characteristics during the process of microscale tracer flow. To clarify the effect of micro heterogeneity on aqueous tracer transport, this paper demonstrates microscopic experiments at pore level and proposes an improved mathematical model for tracer transport. The visualization results show a faster tracer movement into movable water than it into bound water, and quicker occupancy in flowing pores than in storage pores caused by the difference of tracer velocity. Moreover, the proposed mathematical model includes the effects of bound water and flowing porosity by applying interstitial… More >

  • Open Access

    ARTICLE

    Study on the Variation Rule of Produced Oil Components during CO2 Flooding in Low Permeability Reservoirs

    Ganggang Hou1, Tongjing Liu1, *, Xinyu Yuan1, Jirui Hou1, Pengxiang Diwu2
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1223-1246, 2020, DOI:10.32604/cmes.2020.09008
    (This article belongs to this Special Issue: Advances in Modeling and Simulation of Complex Heat Transfer and Fluid Flow)
    Abstract CO2 flooding has been widely studied and applied to improve oil recovery from low permeability reservoirs. Both the experimental results and the oilfield production data indicate that produced oil components (POC) will vary during CO2 flooding in low permeability reservoirs. However, the present researches fail to explain the variation reason and rule. In this study, the physical model of the POC variation during CO2 flooding in low permeability reservoir was established, and the variation reason and rule were defined. To verify the correctness of the physical model, the interaction rule of the oil-CO2 system was studied by related experiments. The… More >

  • Open Access

    ARTICLE

    Numerical Study on the Gas Leakage and Dispersion at the Street Intersection of a Building Group

    Weitao Zhang1, 2, Mengqi Liu3, Kaiyi Wang4, Fan Zhang2, Lei Hou1, *
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1247-1266, 2020, DOI:10.32604/cmes.2020.09297
    (This article belongs to this Special Issue: Advances in Modeling and Simulation of Complex Heat Transfer and Fluid Flow)
    Abstract Accidents involving natural gas leakage and dispersion pose a significant threat to human life and property. This threat is especially relevant at the street intersection at which dense buildings, heavy traffic flow, and complex underground pipe networks meet. Scholars have conducted numerous studies on gas leakage and dispersion, but investigations of natural gas leakage and dispersion at the street intersection of a building group are not in-depth. In this paper, we presented a three-dimensional (3D) physical model based on the Computational Fluid Dynamic (CFD) methodology to study the natural gas leakage and dispersion at the street intersection of a building… More >

  • Open Access

    ARTICLE

    Intelligent Detection Model Based on a Fully Convolutional Neural Network for Pavement Cracks

    Duo Ma1, 2, 3, Hongyuan Fang1, 2, 3, *, Binghan Xue1, 2, 3, Fuming Wang1, 2, 3, Mohammed A. Msekh4, Chiu Ling Chan5
    CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1267-1291, 2020, DOI:10.32604/cmes.2020.09122
    (This article belongs to this Special Issue: Machine Learning based Methods for Mechanics)
    Abstract The crack is a common pavement failure problem. A lack of periodic maintenance will result in extending the cracks and damage the pavement, which will affect the normal use of the road. Therefore, it is significant to establish an efficient intelligent identification model for pavement cracks. The neural network is a method of simulating animal nervous systems using gradient descent to predict results by learning a weight matrix. It has been widely used in geotechnical engineering, computer vision, medicine, and other fields. However, there are three major problems in the application of neural networks to crack identification. There are too… More >

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