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A class of exact solutions for N-dimensional incompressible magnetohydrodynamic equations

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Applied Mathematics and Mechanics(English Edition) 2016年第2期37卷 209-214页

作者： ping liu School of Management Tianjin Normal University

In this paper, a sufficient and necessary condition is presented for existence of a class of exact solutions to N-dimensional incompressible magnetohydrodynamic （MHD） equations. Such solutions can be explicitly expressed by appropriate formulae. Once the required matrices are chosen, solutions to the MHD equations axe directly constructed.

关键词： incompressible magnetohydrodynamic (MHD) equation exact solution symmetric matrix quadratic form curve integration

Coordination of Networked Nonlinear Multi-Agents Using a High-Order Fully Actuated Predictive Control Strategy

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IEEE/CAA Journal of Automatica Sinica 2022年第4期9卷 615-623页

作者： Guo-ping liu IEEE the Department of Electronic and Electrical Engineering Southern University of Science and Technology

This paper is concerned with the coordinative control problem of networked nonlinear multi-agents(NNM)with communication delays.A high-order fully actuated(HOFA)model is introduced to describe the nonlinear *** on this model,a HOFA predictive coordination method is proposed to compensate for the communication delays actively and achieve simultaneous stability and *** method largely simplifies the design of networked nonlinear multi-agents and makes the control performance be same for networked nonlinear multi-agents with and without communication *** analysis on the closed-loop systems derives the simultaneous stability and consensus criteria of networked nonlinear multiagents using the HOFA predictive coordination *** the presented way of designing HOFA predictive coordination controllers,a simulated example demonstrates the advantages of the proposed method.

关键词： method nonlinear coordination

Control Strategies for Digital Twin Systems

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 170-180页

作者： Guo-ping liu IEEE the Center for Control Science and Technology Southern University of Science and TechnologyShenzhen 518055China

With the continuous breakthrough in information technology and its integration into practical applications, industrial digital twins are expected to accelerate their development in the near future. This paper studies various control strategies for digital twin systems from the viewpoint of practical *** make full use of advantages of digital twins for control systems, an architecture of digital twin control systems, adaptive model tracking scheme, performance prediction scheme, performance retention scheme, and fault tolerant control scheme are proposed. Those schemes are detailed to deal with different issues on model tracking, performance prediction, performance retention, and fault tolerant control of digital twin systems. Also, the stability of digital twin control systems is analysed. The proposed schemes for digital twin control systems are illustrated by examples.

关键词： Digital twin control systems fault tolerant control model tracking performance prediction performance retention

Predictive Control of High-Order Fully Actuated Nonlinear Systems with Time-Varying Delays

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Journal of Systems Science & Complexity 2022年第2期35卷 457-470页

作者： liu Guo-ping Department of Electronic and Electrical Engineering Southern University of Science and TechnologyShenzhen 518055China

This paper investigates the control problem of high-order fully actuated nonlinear systems with time-varying delays in the discrete-time *** make the compensation for time-varying delays concise,active and universal,a novel nonlinear predictive control method is *** designed nonlinear predictive controller can achieve the same expected control performance as the nonlinear systems without *** the same time,the necessary and sufficient conditions for the stability of the closed-loop nonlinear predictive control systems are *** examples show that the proposed nonlinear predictive controller design method can completely compensate for the time-varying delays of nonlinear systems.

关键词： High-order fully actuated control systems nonlinear systems predictive control timevarying delays

Networked Learning Predictive Control of Nonlinear Cyber-Physical Systems

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Journal of Systems Science & Complexity 2020年第6期33卷 1719-1732页

作者： liu Guo-ping Department of Artificial Intelligence and Automation Wuhan UniversityWuhan 430072China

Cyber-physical systems integrate computing,network and physical environments to make the systems more efficient and cooperative,and have important and extensive application prospects,such as the Internet of *** paper studies the control problem of nonlinear cyber-physical systems with unknown dynamics and communication delays.A networked learning predictive control scheme is proposed for unknown nonlinear cyber-physical *** scheme recursively learns unknown system dynamics,actively compensates for communication delays and accurately tracks a desired *** multi-step predictors are presented to predict various step ahead outputs of the unknown nonlinear cyber-physical *** optimal design of controllers minimises a performance cost function which measures the tracking error predictions and control input increment *** system analysis leads to the stability criteria of closed-loop nonlinear cyber-physical systems employing the networked learning predictive control *** example illustrates the outcomes of the proposed scheme.

关键词： Cyber-physical systems learning control networked predictive control nonlinear systems

Tracking Control of Multi-Agent Systems Using a Networked Predictive PID Tracking Scheme

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IEEE/CAA Journal of Automatica Sinica 2023年第1期10卷 216-225页

作者： Guo-ping liu IEEE the Center for Control Science and Technology Southern University of Science and TechnologyShenzhen 518055China

With the rapid development of network technology and control technology,a networked multi-agent control system is a key direction of modern industrial control systems,such as industrial Internet *** paper studies the tracking control problem of networked multi-agent systems with communication constraints,where each agent has no information on the dynamics of other agents except their outputs.A networked predictive proportional integral derivative(PPID)tracking scheme is proposed to achieve the desired tracking performance,compensate actively for communication delays,and simplify implementation in a distributed *** scheme combines the past,present and predictive information of neighbour agents to form a tracking error signal for each agent,and applies the proportional,integral,and derivative of the agent tracking error signal to control each individual *** criteria of the stability and output tracking consensus of multi-agent systems with the networked PPID tracking scheme are derived through detailed analysis on the closed-loop *** effectiveness of the networked PPID tracking scheme is illustrated via an example.

关键词： Coordinative tracking control networked multiagent systems PID control predictive control

Instance Segmentation and Berry Counting of Table Grape before Thinning Based on AS-SwinT

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Plant Phenomics 2023年第4期5卷 703-713页

作者： Wensheng Du ping liu Shandong Agricultural Equipment Intelligent Engineering Laboratory Shandong Provincial Key Laboratory of HorticulturalMachinery and EquipmentCollege of Mechanical and Electronic EngineeringShandong Agricultural UniversityTai'an 271000China School of Construction Machinery Shandong Jiaotong UniversityJinan 250357China

Berry thinning is one of the most important tasks in the management of high-quality table *** often thin the berries per cluster to a standard number by *** an aging population,it is hard to find adequate skilled farmers to work during thinning *** is urgent to design an intelligent berry-thinning machine to avoid exhaustive repetitive labor.A machine vision system that can determine the number of berries removed and locate the berries removed is a challenge for the thinning machine.A method for instance segmentation of berries and berry counting in a single bunch is proposed based on *** AS-Swin T,Swin Transformer is performed as the backbone to extract the rich characteristics of grape *** adaptive feature fusion is introduced to the neck network to sufficiently preserve the underlying features and enhance the detection of small *** size of berries in the dataset is statistically analyzed to optimize the anchor scale,and Soft-NMS is used to filter the candidate frames to reduce the missed detection of densely shaded ***,the proposed method could achieve 65.7 AP^(box),95.0 AP^(box)_(0.5),57 AP^(box)_(s),62.8 AP^(mask)94.3 AP^(mask)_(0.5),48 AP^(mask)_(s),which is markedly superior to Mask R-CNN,Mask Scoring R-CNN,and Cascade Mask *** regressions between predicted numbers and actual numbers are also developed to verify the precision of the proposed *** and R^(2)values are 7.13 and 0.95,respectively,which are substantially higher than other models,showing the advantage of the AS-SwinT model in berry counting estimation.

关键词： Berry network removed

Relationship Among Solutions of a Generalized Riccati Equation

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Communications in Theoretical Physics 2007年第4X期48卷 610-614页

作者： liu Xiao-ping liu Chun-ping Institute of Mathematics Yangzhou University Yangzhou 225002 China Gaoyou Branch Yangzhou Education College Gaoyou 225600 China

In this paper, some solutions of a generalized Riccati equation are investigated, which are given in the recent articles [Chaos, Solitons ＆ Fractals 24 （2005） 257; Phys. Lett. A 336 （2005） 463], and the relations... 详细信息

关键词： generalized Riccati equation nonlinear partial differential equations exact solution

2D hetero-structures based on transition metal dichalcogenides:fabrication,properties and applications

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Science Bulletin 2017年第16期62卷 1148-1161页

作者： ping liu Bin Xiang Department of Materials Science&Engineering CAS Key Lab of Materials for Energy Conversionand Synergetic Innovation Center of Quantum Information&Quantum PhysicsUniversity of Science and Technology of ChinaHefei 230026China

Recently,two dimensional transition metal dichalcogenides MX_2(M = Mo,W,etc; X = S,Se,Te) have ignited immense interests because of their unique structural and physical properties for the potential applications in the nano-optoelectronics,valley-spintronics etc. In terms of the structural compatibility and van der Waals interaction,two dimensional(2D) MX_2 layers can be fabricated into various lateral and vertical hetero-structures. The atomically-thin hetero-structures comprising different layered MX_2 provide a new platform for exploring fundamental physics and device technologies with unprecedented phenomenon and extraordinary functionalities. In this review,we report the recent progress about the fabrication,properties and applications of 2D hetero-structures based on transition metal dichalcogenides.

关键词： Transition metal dichalcogenides Hetero-structures Chemical vapor deposition Charge transfer Optoelectronic devices