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  • Open Access


    Research on Anti-Fluctuation Control of Winding Tension System Based on Feedforward Compensation

    Yujie Duan1, Jianguo Liang1,*, Jianglin Liu1, Haifeng Gao1, Yinhui Li2, Jinzhu Zhang1, Xinyu Wen3

    CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.2, pp. 1239-1261, 2024, DOI:10.32604/cmes.2023.044400

    Abstract In the fiber winding process, strong disturbance, uncertainty, strong coupling, and fiber friction complicate the winding constant tension control. In order to effectively reduce the influence of these problems on the tension output, this paper proposed a tension fluctuation rejection strategy based on feedforward compensation. In addition to the bias harmonic curve of the unknown state, the tension fluctuation also contains the influence of bounded noise. A tension fluctuation observer (TFO) is designed to cancel the uncertain periodic signal, in which the frequency generator is used to estimate the critical parameter information. Then, the fluctuation signal is reconstructed by a… More >

  • Open Access


    Numerical Simulation of Slurry Diffusion in Fractured Rocks Considering a Time-Varying Viscosity

    Lei Zhu1,2, Bin Liu2, Xuewei Liu2,*, Wei Deng1, Wenjie Yao1, Ying Fan1

    FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.2, pp. 401-427, 2024, DOI:10.32604/fdmp.2023.041444

    Abstract To analyze the effects of a time-varying viscosity on the penetration length of grouting, in this study cement slurries with varying water-cement ratios have been investigated using the Bingham’s fluid flow equation and a discrete element method. A fluid-solid coupling numerical model has been introduced accordingly, and its accuracy has been validated through comparison of theoretical and numerical solutions. For different fracture forms (a single fracture, a branch fracture, and a fracture network), the influence of the time-varying viscosity on the slurry length range has been investigated, considering the change in the fracture aperture. The results show that under different… More >

  • Open Access


    A Time-Varying Parameter Estimation Method for Physiological Models Based on Physical Information Neural Networks

    Jiepeng Yao1,2, Zhanjia Peng1,2, Jingjing Liu1,2, Chengxiao Fan1,2, Zhongyi Wang1,2,3, Lan Huang1,2,*

    CMES-Computer Modeling in Engineering & Sciences, Vol.137, No.3, pp. 2243-2265, 2023, DOI:10.32604/cmes.2023.028101

    Abstract In the establishment of differential equations, the determination of time-varying parameters is a difficult problem, especially for equations related to life activities. Thus, we propose a new framework named BioE-PINN based on a physical information neural network that successfully obtains the time-varying parameters of differential equations. In the proposed framework, the learnable factors and scale parameters are used to implement adaptive activation functions, and hard constraints and loss function weights are skillfully added to the neural network output to speed up the training convergence and improve the accuracy of physical information neural networks. In this paper, taking the electrophysiological differential… More >

  • Open Access


    Application of Hankel Dynamic Mode Decomposition for Wide Area Monitoring of Subsynchronous Resonance

    Lei Wang1, Tiecheng Li1, Hui Fan2, Xuekai Hu1, Lin Yang3, Xiaomei Yang3,*

    Energy Engineering, Vol.120, No.4, pp. 851-867, 2023, DOI:10.32604/ee.2023.025383

    Abstract In recent years, subsynchronous resonance (SSR) has frequently occurred in DFIG-connected series-compensated systems. For the analysis and prevention, it is of great importance to achieve wide area monitoring of the incident. This paper presents a Hankel dynamic mode decomposition (DMD) method to identify SSR parameters using synchrophasor data. The basic idea is to employ the DMD technique to explore the subspace of Hankel matrices constructed by synchrophasors. It is analytically demonstrated that the subspace of these Hankel matrices is a combination of fundamental and SSR modes. Therefore, the SSR parameters can be calculated once the modal parameter is extracted. Compared… More >

  • Open Access


    Comparison of Time-Varying Pattern of Recurrence in Chinese Breast Cancer Patients with Different Molecular Subtypes: A Single-Center Retrospective Study

    Xujie Zhou1,2,3,#, Yuting Sang1,3,#, Jiajian Chen1,3, Miao Mo3,4, Jianjing Hou1,3, Benlong Yang1,3,*, Jiong Wu1,2,3,*

    Oncologie, Vol.24, No.3, pp. 451-469, 2022, DOI:10.32604/oncologie.2022.025226

    Abstract Background: To compare the time-varying recurrence patterns of different molecular subtypes of breast cancer in the contemporary era with those in the past era. Patients and Methods: This retrospective study included 14627 consecutive invasive breast cancer patients who underwent surgery from 2008 to 2016 at Fudan University Shanghai Cancer Center. We defined the period from 2013 to 2016 as the contemporary era and that from 2008 to 2012 as the past era. Five subtypes were defined according to the immunohistochemistry results. Emphasis was made on the changing patterns of recurrence for patients with different molecular subtypes changed between the two… More >

  • Open Access


    Fixed-Time Adaptive Time-Varying Matrix Projective Synchronization of Time-Delayed Chaotic Systems with Different Dimensions

    Peng Zheng1, Xiaozhen Guo2,*, Guoguang Wen3

    CMES-Computer Modeling in Engineering & Sciences, Vol.131, No.3, pp. 1451-1463, 2022, DOI:10.32604/cmes.2022.019769

    Abstract This paper deals with the fixed-time adaptive time-varying matrix projective synchronization (ATVMPS) of different dimensional chaotic systems (DDCSs) with time delays and unknown parameters. Firstly, to estimate the unknown parameters, adaptive parameter updated laws are designed. Secondly, to realize the fixed-time ATVMPS of the time-delayed DDCSs, an adaptive delay-unrelated controller is designed, where time delays of chaotic systems are known or unknown. Thirdly, some simple fixed-time ATVMPS criteria are deduced, and the rigorous proof is provided by employing the inequality technique and Lyapunov theory. Furthermore, the settling time of fixed-time synchronization (Fix-TS) is obtained, which depends only on controller parameters… More >

  • Open Access


    Effect of Alternation of Aging and Seawater Erosion on Properties of Rubber Material Used in Lead Rubber Bearing

    Yanmin Li1,2, Guifeng Zhao2,3, Yuhong Ma1,2,*, Rong Liu1,2

    Journal of Renewable Materials, Vol.10, No.6, pp. 1641-1658, 2022, DOI:10.32604/jrm.2022.018277

    Abstract An artificially accelerated alternation of aging and seawater erosion test of rubber materials used in lead rubber bearing (LRB) was performed, mainly to study the time-varying laws of rubber materials mechanical properties. Time-varying laws of the Mooney–Rivlin and Neo-Hookean constitutive parameters of rubber materials under the alternation of aging and seawater erosion were also analyzed. Results indicate that the rubber material mechanical properties were significantly affected by alternation of aging and seawater erosion. Hardness and elongation stress increased exponentially with test time. And 120 days after the test, the hardness increased by 14%, the maximum percentage increase in stress of… More >

  • Open Access


    Optimal Parameter Estimation of Transmission Line Using Chaotic Initialized Time-Varying PSO Algorithm

    Abdullah Shoukat1, Muhammad Ali Mughal1,*, Saifullah Younus Gondal1, Farhana Umer2, Tahir Ejaz3, Ashiq Hussain1

    CMC-Computers, Materials & Continua, Vol.71, No.1, pp. 269-285, 2022, DOI:10.32604/cmc.2022.021575

    Abstract Transmission line is a vital part of the power system that connects two major points, the generation, and the distribution. For an efficient design, stable control, and steady operation of the power system, adequate knowledge of the transmission line parameters resistance, inductance, capacitance, and conductance is of great importance. These parameters are essential for transmission network expansion planning in which a new parallel line is needed to be installed due to increased load demand or the overhead line is replaced with an underground cable. This paper presents a method to optimally estimate the parameters using the input-output quantities i.e., voltages,… More >

  • Open Access


    Implementation of Legendre Neural Network to Solve Time-Varying Singular Bilinear Systems

    V. Murugesh1, B. Saravana Balaji2,*, Habib Sano Aliy3, J. Bhuvana4, P. Saranya5, Andino Maseleno6, K. Shankar7, A. Sasikala8

    CMC-Computers, Materials & Continua, Vol.69, No.3, pp. 3685-3692, 2021, DOI:10.32604/cmc.2021.017836

    Abstract Bilinear singular systems can be used in the investigation of different types of engineering systems. In the past decade, considerable attention has been paid to analyzing and synthesizing singular bilinear systems. Their importance lies in their real world application such as economic, ecological, and socioeconomic processes. They are also applied in several biological processes, such as population dynamics of biological species, water balance, temperature regulation in the human body, carbon dioxide control in lungs, blood pressure, immune system, cardiac regulation, etc. Bilinear singular systems naturally represent different physical processes such as the fundamental law of mass action, the DC motor,… More >

  • Open Access


    Model Predictive Control for Nonlinear Energy Management of a Power Split Hybrid Electric Vehicle

    Dehua Shi1,4, Shaohua Wang1,2,*, Yingfeng Cai1, Long Chen1, ChaoChun Yuan1, ChunFang Yin3

    Intelligent Automation & Soft Computing, Vol.26, No.1, pp. 27-39, 2020, DOI:10.31209/2018.100000062

    Abstract Model predictive control (MPC), owing to the capability of dealing with nonlinear and constrained problems, is quite promising for optimization. Different MPC strategies are investigated to optimize HEV nonlinear energy management for better fuel economy. Based on Bellman’s principle, dynamic programming is firstly used in the limited horizon to obtain optimal solutions. By considering MPC as a nonlinear programming problem, sequential quadratic programming (SQP) is used to obtain the descent directions of control variables and the current control input is further derived. To reduce computation and meet the requirements of real-time control, the nonlinear model of the system is approximated… More >

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