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  • Open Access

    ARTICLE

    Analysis of the Mechanism and Effectiveness of Lignin in Improving the High-Temperature Thermal Stability of Asphalt

    Cheng Cheng1,2,*, Weiwei Sun2, Bo Hu3, Guixiang Tao2, Chao Peng2, Yanjuan Tian4, Shujuan Wu4,5

    Journal of Renewable Materials, Vol., , DOI:10.32604/jrm.2020.012054

    Abstract The use of lignin, which is a by-product of the pulp and paper industry, in the development of asphalt binders would contribute to waste reduction, providing environmental, economic, and social benefits. In this study, samples of lignin-modified asphalt binder samples with different content of lignin (3%, 6%, 9%, 12%, and 15%) and unmodified asphalt (control) were tested using Fourier transform infrared spectroscopy (FTIR), dynamic shear rheometer (DSR), and thermogravimetry. The mechanism and effectiveness of lignin in improving the thermal stability of asphalt at high temperatures were analyzed. The FTIR analysis shows that no new characteristic absorption peak is seen in… More >

  • Open Access

    ARTICLE

    Robust Design Optimization and Improvement by Metamodel

    Shufang Song*, Lu Wang, Yuhua Yan

    CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.09588

    Abstract The robust design optimization (RDO) is an effective method to improve product performance with uncertainty factors. The robust optimal solution should be not only satisfied the probabilistic constraints but also less sensitive to the variation of design variables. There are some important issues in RDO, such as how to judge robustness, deal with multi-objective problem and black-box situation. In this paper, two criteria are proposed to judge the deterministic optimal solution whether satisfies robustness requirment. The robustness measure based on maximum entropy is proposed. Weighted sum method is improved to deal with the objective function, and the basic framework of… More >

  • Open Access

    ARTICLE

    Topp-Leone Odd Fréchet Generated Family of Distributions with Applications to COVID-19 Data Sets

    Sanaa Al-Marzouki1, Farrukh Jamal2, Christophe Chesneau3,*, Mohammed Elgarhy4

    CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.011521

    Abstract Recent studies have pointed out the potential of the odd Fréchet family (or class) of continuous distributions in fitting data of all kinds. In this article, we propose an extension of this family through the so-called “Topp-Leone strategy”, aiming to improve its overall flexibility by adding a shape parameter. The main objective is to offer original distributions with modifiable properties, from which adaptive and pliant statistical models can be derived. For the new family, these aspects are illustrated by the means of comprehensive mathematical and numerical results. In particular, we emphasize a special distribution with three parameters based on the… More >

  • Open Access

    ARTICLE

    A Multi-View Gait Recognition Method Using Deep Convolutional Neural Network and Channel Attention Mechanism

    Jiabin Wang*, Kai Peng

    CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.011046

    Abstract In many existing multi-view gait recognition methods based on images or video sequences, gait sequences are usually used to superimpose and synthesize images and construct energy-like template. However, information may be lost during the process of compositing image and capture EMG signals. Errors and the recognition accuracy may be introduced and affected respectively by some factors such as period detection. To better solve the problems, a multi-view gait recognition method using deep convolutional neural network and channel attention mechanism is proposed. Firstly, the sliding time window method is used to capture EMG signals. Then, the back-propagation learning algorithm is used… More >

  • Open Access

    ARTICLE

    Research on Trajectory Tracking Method of Redundant Manipulator Based on PSO Algorithm Optimization

    Shifu Xu*, Yanan Jiang

    CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.09608

    Abstract Aiming at the problem that the trajectory tracking performance of redundant manipulator corresponding to the target position is difficult to optimize, the trajectory tracking method of redundant manipulator based on PSO algorithm optimization is studied. The kinematic diagram of redundant manipulator is created, to derive the equation of motion trajectory of redundant manipulator end. Pseudo inverse Jacobi matrix is used to solve the problem of manipulator redundancy. Based on the tracking ellipse of redundant manipulator, the tracking shape of redundant manipulator is determined with the overall tracking index as the second index, and the optimization method of tracking index is… More >

  • Open Access

    ARTICLE

    Online AUV Path Replanning Using Quantum-Behaved Particle Swarm Optimization with Selective Differential Evolution

    Hui Sheng Lim1,*, Christopher K. H. Chin1, Shuhong Chai1, Neil Bose1,2

    CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.011648

    Abstract This paper presents an online AUV (autonomous underwater vehicle) path planner that employs path replanning approach and the SDEQPSO (selective differential evolution-hybridized quantum-behaved particle swarm optimization) algorithm to optimize an AUV mission conducted in an unknown, dynamic and cluttered ocean environment. The proposed path replanner considered the effect of ocean currents in path optimization to generate a Pareto-optimal path that guides the AUV to its target within minimum time. The optimization was based on the onboard sensor data measured from the environment, which consists of a priori unknown dynamic obstacles and spatiotemporal currents. Different sensor arrangements for the forward-looking sonar… More >

  • Open Access

    ARTICLE

    Ziegler–Nichols Customization for Quadrotor Attitude Control under Empty and Full Loading Conditions

    Ivan Paulo Canal1,*, Manuel Martin Pérez Reimbold2, Maurício de Campos2

    CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.010741

    Abstract An aircraft quadrotor is a complex control system that allows for great flexibility in flight. Controlling multirotor aerial systems such as quadrotors is complex because the variables involved are not always available, known, and accurate. The inclusion of payload changes the dynamic characteristics of the aircraft, making it necessary to adapt the control system for this situation. Among the various control methods that have been investigated, proportional-integralderivative (PID) control offers good results and simplicity of application; however, achieving stability and high performance is challenging, with the most critical task being tuning the controller gains. The Ziegler–Nichols (ZN) theory was used… More >

  • Open Access

    ARTICLE

    Interpolating Isogeometric Boundary Node Method and Isogeometric Boundary Element Method Based on Parameter Space

    Hongyin Yang1,2, Jiwei Zhong1,*, Ying Wang3, Xingquan Chen2, Xiaoya Bian2

    CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.010936

    Abstract In this paper, general interpolating isogeometric boundary node method (IIBNM) and isogeometric boundary element method (IBEM) based on parameter space are proposed for 2D elasticity problems. In both methods, the integral cells and elements are defined in parameter space, which can reproduce the geometry exactly at all the stages. In IIBNM, the improved interpolating moving leastsquare method (IIMLS) is applied for field approximation and the shape functions have the delta function property. The Lagrangian basis functions are used for field approximation in IBEM. Thus, the boundary conditions can be imposed directly in both methods. The shape functions are defined in… More >

  • Open Access

    ARTICLE

    Design of a Multichannel Dynamic Temperature Measurement System for Developing Thermal Management System of New Energy Vehicles

    Wei Li1, Shusheng Xiong2,*, Xiaojun Zhou1, Wei Shi3

    Energy Engineering, Vol., , DOI:10.32604/EE.2020.011506

    Abstract A multichannel temperature measurement system based on LabVIEW and modular instruments with general purpose input/output interface is described. External simple electronic components, such as analog switches arrays, sampling resistors and voltage reference are used to expand the analog input channel of the instrument. The interface circuit for 3-wire resistance temperature device powered by the voltage reference was designed and constructed. The feasibility of filtering algorithm based on moving average filter and the data conversion method by direct computation of the polynomial are verified in LabVIEW. A comparison test with the commercial temperature measurement instrument is conducted to test the same… More >

  • Open Access

    ARTICLE

    Effect of Hole Density and Confining Pressure on Mechanical Behavior of Porous Specimens: An Insight from Discrete Element Modeling

    Yuanchao Zhang1, Zhiyuan Xia2,*, Yujing Jiang1, Miao Chen3, Jiankang Liu1, Qian Yin4

    CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.011076

    Abstract Hole-like defects are very common in natural rock or coal mass, and play an important role in the failure and mechanical behaviors of rock or coal mass. In this research, multi-holed coal specimens are constructed numerically and calibrated based on UDEC-GBM models. Then, the strength, deformation and failure behavior of the porous specimens are analyzed, with consideration of hole density (P) and confining pressure (σ3). The simulation results are highly consistent with those available experiment results, and show that the compressive strength decreases exponentially with the increasing hole density. The strength loss is mainly caused by the reduction of cohesion… More >

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