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Resonantly enhanced second-and third-harmonic generation in dielectric nonlinear metasurfaces

Opto-Electronic Advances 2024年第5期7卷 5-19页

作者： Ji Tong Wang Pavel Tonkaev Kirill Koshelev Fangxing Lai Sergey Kruk Qinghai Song Yuri Kivshar Nicolae C.Panoiu Department of Electronic and Electrical Engineering University College LondonLondon WC1E 7JEUnited Kingdom nonlinear Physics Center Research School of PhysicsAustralian National UniversityCanberra ACT 2601Australia Ministry of Industry and Information Technology Key lab of Micro-Nano Optoelectronic Information System Guangdong Provincial Key Laboratory of Semiconductor Optoelectronic Materials and Intelligent Photonic SystemsHarbin Institute of TechnologyShenzhen 518055China Wuzhen laboratory EGO Wuzhen Digital Economy Industrial ParkNo.925 Daole RoadTongxiangChina

nonlinear dielectric metasurfaces provide a promising approach to control and manipulate frequency conversion optical processes at the nanoscale,thus facilitating both advances in fundamental research and the development of new practical applications in photonics,lasing,and ***,we employ symmetry-broken metasurfaces made of centrosymmetric amorphous silicon for resonantly enhanced second-and third-order nonlinear optical *** the rich physics of optical quasi-bound states in the continuum and guided mode resonances,we comprehensively study through rigorous numerical calculations the relative contribution of surface and bulk effects to second-harmonic generation(SHG)and the bulk contribution to third-harmonic generation(THG) from the ***,we experimentally achieve optical resonances with high quality factors,which greatly boosts light-matter interaction,resulting in about 550 times SHG enhancement and nearly 5000-fold increase of THG.A good agreement between theoretical predictions and experimental measurements is *** gain deeper insights into the physics of the investigated nonlinear optical processes,we further numerically study the relation between nonlinear emission and the structural asymmetry of the metasurface and reveal that the generated harmonic signals arising from linear sharp resonances are highly dependent on the asymmetry of the *** work suggests a fruitful strategy to enhance the harmonic generation and effectively control different orders of harmonics in all-dielectric metasurfaces,enabling the development of efficient active photonic nanodevices.

关键词： second-harmonic generation third-harmonic generation bound state in the continuum guided mode resonance all-dielectric metasurfaces nonlinear optics

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A game-theoretic approach for federated learning:A trade-off among privacy,accuracy and energy

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digital Communications and Networks 2024年第2期10卷 389-403页

作者： Lihua Yin Sixin Lin Zhe Sun Ran Li Yuanyuan He Zhiqiang Hao Cyberspace Institute of Advanced Technology Guangzhou UniversityGuangzhou510006China School of Cyber Science and Engineering Huazhong University of Science and TechnologyWuhan430074China China Industrial control systems Cyber Emergency Response Team Beijing100040China

Benefiting from the development of Federated Learning(FL)and distributed communication systems,large-scale intelligent applications become *** devices not only provide adequate training data,but also cause privacy leakage and energy *** to optimize the energy consumption in distributed communication systems,while ensuring the privacy of users and model accuracy,has become an urgent *** this paper,we define the FL as a 3-layer architecture including users,agents and *** order to find a balance among model training accuracy,privacy-preserving effect,and energy consumption,we design the training process of FL as game *** use an extensive game tree to analyze the key elements that influence the players’decisions in the single game,and then find the incentive mechanism that meet the social norms through the repeated *** experimental results show that the Nash equilibrium we obtained satisfies the laws of reality,and the proposed incentive mechanism can also promote users to submit high-quality data in *** the multiple rounds of play,the incentive mechanism can help all players find the optimal strategies for energy,privacy,and accuracy of FL in distributed communication systems.

关键词： Federated learning Privacy preservation Energy optimization Game theory Distributed communication systems

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Adaptive neural network control of a 2-DOF helicopter system considering input constraints and global prescribed performance

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Science China(Information Sciences) 2024年第7期67卷 224-239页

作者： Zhijia ZHAO Jiale WU Zhijie LIU We HE C.L.Philip CHEN School of Mechanical and Electrical Engineering Guangzhou University School of Intelligence Science and Technology and Key laboratory of Intelligent Bionic Unmanned systems of Ministry of Education University of Science and Technology Beijing School of Computer Science and Engineering South China University of Technology Pazhou lab

In this study, an adaptive neural network(NN) control is proposed for nonlinear two-degree-offreedom(2-DOF) helicopter systems considering the input constraints and global prescribed ***, radial basis function NN(RBFNN) is employed to estimate the unknown dynamics of the helicopter system. Second, a smooth nonaffine function is exploited to approximate and address nonlinear constraint functions. Subsequently, a new prescribed function is proposed, and an original constrained error is transformed into an equivalent unconstrained error using the error transformation and barrier function transformation methods. The analysis of the established Lyapunov function proves that the controlled system is globally uniformly bounded. Finally, the simulation and experimental results on a constructed Quanser's test platform verify the rationality and feasibility of the proposed control.

关键词： adaptive NN control 2-DOF helicopter global prescribed performance input constraints

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Non-smooth finite-time stabilization for a class of nonlinear systems

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Science in China(Series F) 2006年第1期49卷 80-89页

作者： HONG Yiguang WANG Jiankui lab of systems and control Institute of Systems Science Chinese Academy of Sciences. Beijing 100080China

In this paper, global finite-time stabilization problem for a large class of nonlinear control systems is considered. An iterative design approach is given based on Lyapunov function. The finite time stabilizing contr... 详细信息

关键词： finite-time control p normal form global stabilization.

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Kinematic and Dynamic Analysis of 3-DOF Rotary Table Manipulator

Kinematic and Dynamic Analysis of 3-DOF Rotary Table Manipul...

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2009中国控制与决策会议

作者： Masoud Dorosti Jafar Heyrani Nobari digital and nonlinear control systems lab Electrical Engineering DepartmentK.N.Toosi University of TechnologyTehranIran

＜正＞3-DOF Rotary Table manipulator is a robotic mechanism which brings about spatial rotational movements. This mechanism helps to make a movement scenario in order to test Guidance and Navigation systems of moving *** has complicated dynamic equations which are crucial for control *** this paper,we study applicable kinematics of this ***,we choose the best kinematics and try to get the dynamic equations by applying the Newton’s Second Law for *** use the Newton’s Second Law instead of using common methods in robotic modeling such as Denavit-Hartenberg and Newton-Euler *** have extracted full dynamic equations that contain all designing parameters such as Moment of Inertia factor in all round and even the unbalanced and wobble *** we have verified obtained equations by simulation.

关键词： 3-DOF Rotary Table Manipulator Gimbal Unit under Test Dynamic Equations

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Parameter-dependent vibration-attenuation controller design for electro-hydraulic actuated linear structural systems

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Earthquake Engineering and Engineering Vibration 2012年第1期11卷 73-82页

作者： Weng Falu Mao Weijie State Key lab of Industrial control Technology Institute of Cyber-Systems and Control Zhejiang University Hangzhou 310027 China School of Mechanical and Electrical Engineering Jiangxi University of Science and Technology Ganzhou 341000 China

The problem of robust active vibration control for a class of electro-hydraulic actuated structural systems with time-delay in the control input channel and parameter uncertainties appearing in all the mass, damping and stiffness matrices is investigated in this paper. First, by introducing a linear varying parameter, the nonlinear system is described as a linear parameter varying （LPV） model. Second, based on this LPV model, an LMI-based condition for the system to be asymptotically stabilized is deduced. By solving these LMIs, a parameter-dependent controller is established for the closed- loop system to be stable with a prescribed level of disturbance attenuation. The condition is also extended to the uncertain case. Finally, some numerical simulations demonstrate the satisfying performance of the proposed controller.

关键词： structural system electro-hydraulic servo system robust stabilization vibration attenuation parameter-dependent controller

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Delay-dependent robust H∞ control for a class of uncertain switched systems with time delay

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Journal of Zhejiang University Science 2004年第7期5卷 841-850页

作者：师佳吴铁军杜树新 National Key lab for Industrial control Technology Institute of Intelligent Systems and Decision MakingZhejiang UniversityHangzhou 310027China

For linear switched system with both parameter uncertainties and time delay, a delay-dependent sufficient condition for the existence of a new robust H∞ feedback controller was formulated in nonlinear matrix inequalities solvable by an LMI-based iterative algorithm. Compared with the conventional state-feedback controller, the proposed controller can achieve better robust control performance since the delayed state is utilized as additional feedback information and the parameters of the proposed controllers are changed synchronously with the dynamical characteristic of the system. This design method was also extended to the case where only delayed state is available for the controller. The example of balancing an inverted pendulum on a cart demonstrates the effectiveness and applicability of the proposed design methods.

关键词： Linear switched systems Robust H∞ control Matrix inequality Time delay

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Quasi-Newton method based control design for unknown nonlinear systems with input constraints

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Science China(Information Sciences) 2020年第5期63卷 224-226页

作者： Shuangshuang XIONG Zhongsheng HOU Chenkun YIN Advanced control systems lab School of Electronic and Information EngineeringBeijing Jiaotong University School of Automation Qingdao University

Dear editor,With the development in digital computers, various and huge data of controlled plants are obtained and stored, which has led to a rapid growth in the application of numerical methods in controller design. In recent years, the quasi-Newton method [1, 2], as one of the powerful numerical methods which has superlinear convergence speed

关键词： Newton Quasi-Newton method based control design for unknown nonlinear systems with input constraints

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nonlinear boundary control problem of hyperbolic systems

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Journal of control and Decision 2024年第1期11卷 73-83页

作者： A.Bouhamed A.El Kabouss H.Bouzahir ISTI lab Ibn Zohr UniversityENSAAgadirMorocco Faculty of sciences Moulay Ismail UniversityMeknesMorocco

The paper is devoted to the study of optimal control of a hyperbolic system,where the control enters the system through the *** hyperbolic system is the wave equation on a smooth and open domain,where the boundary condition involves the normal derivative at the boundary of z,the time derivative of z times a constant k,and a nonlinear term ***,z is the state and u is the control,satisfying some boundedness condition depending on *** functional cost consists of the energy and the difference between the solution of the system at final time,and a desired state in *** a closed convex set,we prove the existence of an optimal control that minimises the cost functional using a priori ***,using the differentiability of the cost functional with respect to the control,we establish the characterisation by deriving necessary conditions that an optimal control must satisfy.A numerical approach is successfully illustrated by simulations.

关键词： Non-linear system hyperbolic system boundary control optimal control controllability

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Recent advances on analysis and design of switched linear systems

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control Theory and Technology 2017年第3期15卷 242-244页

作者： Zhendong SUN Key lab of systems & control Academy of Mathematics & Systems Science Chinese Academy of Sciences Beijing 100190 China School of Mathematical Science University of Chinese Academy of Sciences Beijing 100049 China

A switched linear system is a special hybrid system that consists of a set of linear continuous-time/discrete-time subsystems and a rule that orchestrates the switching among them. The two-level （execution-supervision） structure makes the switched system theoretically interesting and practically attractive. Under active investigation for more than three decades, huge progress has been made in understanding the dynamical behavior of switched systems. In particular, it has been well recognized that, a switched linear system could produce highly nonlinear ＆ complex behaviors, for instance, controllability might not imply stabilizability, and stabilizability might not imply the existence of convex （control-）Lyapunov function.

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