In this paper,the synchronizable system by groups and the generalized synchronizable system are studied for a coupled system of wave equations.Moreover,situations possessing different groupings are also discussed.
This paper propose a comprehensive data-driven prediction framework based on machine learning methods to investigate the lag synchronization phenomenon in coupled chaotic systems,particularly in cases where accurate m...This paper propose a comprehensive data-driven prediction framework based on machine learning methods to investigate the lag synchronization phenomenon in coupled chaotic systems,particularly in cases where accurate mathematical models are challenging to establish or where system equations remain unknown.The Long Short-Term Memory(LSTM)neural network is trained using time series acquired from the desynchronization system states,subsequently predicting the lag synchronization transition.In the experiments,we focus on the Lorenz system with time-varying delayed coupling,studying the effects of coupling coefficients and time delays on lag synchronization,respectively.The results indicate that with appropriate training,the machine learning model can adeptly predict the lag synchronization occurrence and transition.This study not only enhances our comprehension of complex network synchronization behaviors but also underscores the potential and practical applications of machine learning in exploring nonlinear dynamic systems.展开更多
Dear Editor,This letter proposes a deep synchronization control(DSC) method to synchronize grid-forming converters with power grids. The method involves constructing a novel controller for grid-forming converters base...Dear Editor,This letter proposes a deep synchronization control(DSC) method to synchronize grid-forming converters with power grids. The method involves constructing a novel controller for grid-forming converters based on the stable deep dynamics model. To enhance the performance of the controller, the dynamics model is optimized within the deep reinforcement learning(DRL) framework. Simulation results verify that the proposed method can reduce frequency deviation and improve active power responses.展开更多
This article briefly reviews the topic of complex network synchronization,with its graph-theoretic criterion,showing that the homogeneous and symmetrical network structures are essential for optimal synchronization.Fu...This article briefly reviews the topic of complex network synchronization,with its graph-theoretic criterion,showing that the homogeneous and symmetrical network structures are essential for optimal synchronization.Furthermore,it briefly reviews the notion of higher-order network topologies and shows their promising potential in application to evaluating the optimality of network synchronizability.展开更多
This study presents an emergency control method for sub-synchronous oscillations in wind power gridconnected systems based on transfer learning,addressing the issue of insufficient generalization ability of traditiona...This study presents an emergency control method for sub-synchronous oscillations in wind power gridconnected systems based on transfer learning,addressing the issue of insufficient generalization ability of traditional methods in complex real-world scenarios.By combining deep reinforcement learning with a transfer learning framework,cross-scenario knowledge transfer is achieved,significantly enhancing the adaptability of the control strategy.First,a sub-synchronous oscillation emergency control model for the wind power grid integration system is constructed under fixed scenarios based on deep reinforcement learning.A reward evaluation system based on the active power oscillation pattern of the system is proposed,introducing penalty functions for the number of machine-shedding rounds and the number of machines shed.This avoids the economic losses and grid security risks caused by the excessive one-time shedding of wind turbines.Furthermore,transfer learning is introduced into model training to enhance the model’s generalization capability in dealing with complex scenarios of actual wind power grid integration systems.By introducing the Maximum Mean Discrepancy(MMD)algorithm to calculate the distribution differences between source data and target data,the online decision-making reliability of the emergency control model is improved.Finally,the effectiveness of the proposed emergency control method for multi-scenario sub-synchronous oscillation in wind power grid integration systems based on transfer learning is analyzed using the New England 39-bus system.展开更多
Projective synchronization problems of a drive system and a particular response network were investigated,where the drive system is an arbitrary system with n+1 dimensions;it may be a linear or nonlinear system,and ev...Projective synchronization problems of a drive system and a particular response network were investigated,where the drive system is an arbitrary system with n+1 dimensions;it may be a linear or nonlinear system,and even a chaotic or hyperchaotic system,the response network is complex system coupled by N nodes,and every node is showed by the approximately linear part of the drive system.Only controlling any one node of the response network by designed controller can achieve the projective synchronization.Some numerical examples were employed to verify the effectiveness and correctness of the designed controller.展开更多
Permanent magnet synchronous motor(PMSM),known for their compact size and high-power density,is widely used in fields such as electric vehicles and servo drives.However,traditional PID control methods for PMSM cannot ...Permanent magnet synchronous motor(PMSM),known for their compact size and high-power density,is widely used in fields such as electric vehicles and servo drives.However,traditional PID control methods for PMSM cannot dynamically adjust parameters according to varying operating conditions.To address this issue,this paper proposes a PID control method based on a radial basis function(RBF)neural network,which adaptively tunes the PID controller parameters.First,an offline RBF neural network with optimal structural parameters is trained using the current and speed data of the PMSM,and then employed to construct the RBF-PID controller.During online training,the Jacobian information calculated via the RBF neural network is used to adaptively adjust the PID parameters.Simultaneously,the structural parameters of the RBF network are updated in reverse based on the error between the predicted and reference speed values.Finally,numerical simulations and experiments in the context of electric vehicle drive control show that the maximum speed errors of the SMC controller and the RBF-PID controller are 1.97 km/h and 0.17 km/h,respectively.Moreover,the RBF-PID controller outperforms both the SMC and traditional PID controllers in handling sudden speed changes.展开更多
Recently,large-scale trapped ion systems have been realized in experiments for quantum simulation and quantum computation.They are the simplest systems for dynamical stability and parametric resonance.In this model,th...Recently,large-scale trapped ion systems have been realized in experiments for quantum simulation and quantum computation.They are the simplest systems for dynamical stability and parametric resonance.In this model,the Mathieu equation plays the most fundamental role for us to understand the stability and instability of a single ion.In this work,we investigate the dynamics of trapped ions with the Coulomb interaction based on the Hamiltonian equation.We show that the many-body interaction will not influence the phase diagram for instability.Then,the dynamics of this model in the large damping limit will also be analytically calculated using few trapped ions.Furthermore,we find that in the presence of modulation,synchronization dynamics can be observed,showing an exchange of velocities between distant ions on the left side and on the right side of the trap.These dynamics resemble that of the exchange of velocities in Newton's cradle for the collision of balls at the same time.These dynamics are independent of their initial conditions and the number of ions.As a unique feature of the interacting Mathieu equation,we hope this behavior,which leads to a quasi-periodic solution,can be measured in current experimental systems.Finally,we have also discussed the effect of anharmonic trapping potential,showing the desynchronization during the collision process.It is hoped that the dynamics in this many-body Mathieu equation with damping may find applications in quantum simulations.This model may also find interesting applications in dynamics systems as a pure mathematical problem,which may be beyond the results in the Floquet theorem.展开更多
This paper investigates modified fixed-time synchronization(FxTS)of complex networks(CNs)with time-varying delays based on continuous and discontinuous controllers.First,for the sake of making the settling time(ST)of ...This paper investigates modified fixed-time synchronization(FxTS)of complex networks(CNs)with time-varying delays based on continuous and discontinuous controllers.First,for the sake of making the settling time(ST)of FxTS is independent of the initial values and parameters of the CNs,a modified fixed-time(FxT)stability theorem is proposed,where the ST is determined by an arbitrary positive number given in advance.Then,continuous controller and discontinuous controller are designed to realize the modified FxTS target of CNs.In addition,based on the designed controllers,CNs can achieve synchronization at any given time,or even earlier.And control strategies effectively solve the problem of ST related to the parameters of CNs.Finally,an appropriate simulation example is conducted to examine the effectiveness of the designed control strategies.展开更多
Optical wireless(OW)communication systems face significant challenges such as signal attenuation due to atmospheric absorption,scattering,and noise from hardware components,which degrade detection sensitivity.To addre...Optical wireless(OW)communication systems face significant challenges such as signal attenuation due to atmospheric absorption,scattering,and noise from hardware components,which degrade detection sensitivity.To address these challenges,we propose a digital processing algorithm that combines finite impulse response filtering with dynamic synchronization based on pulse addition and subtraction.Unlike conventional methods,which typically rely solely on hardware optimization or basic thresholding techniques,the proposed approach integrates filtering and synchronization to improve weak signal detection and reduce noise-induced errors.The proposed algorithm was implemented and verified using a field-programmable gate array.Experiments conducted in an indoor OW communication environment demonstrate that the proposed algorithm significantly improves detection sensitivity by approximately 6 dB and 5 dB at communication rates of 3.5 Mbps and 5.0 Mbps,respectively.Specifically,under darkroom conditions and a bit error rate of 1×10^(-7),the detection sensitivity was improved from-38.56 dBm to-44.77 dBm at 3.5 Mbps and from-37.12 dBm to-42.29 dBm at 5 Mbps.The proposed algorithm is crucial for future capture and tracking of signals at large dispersion angles and in underwater and long-distance communication scenarios.展开更多
This paper explores the synchronization of stochastic simplicial complexes with noise,modeled by stochastic differential equations of It?type.It establishes the relationship between synchronization and individual dyna...This paper explores the synchronization of stochastic simplicial complexes with noise,modeled by stochastic differential equations of It?type.It establishes the relationship between synchronization and individual dynamics,higher-order structures,coupling strengths,and noise.In particular,this study delves into the role of multi-body interactions,particularly focusing on the influence of higher-order simplicial structures on the overall synchronization behavior.Furthermore,the effects of noise on synchronizability in the stochastic simplicial complex are thoroughly examined.The obtained results indicate that the effects of noise on the synchronizability vary with the manner in which noise propagates.The presence of noise can regulate the synchronization pattern of the simplicial complex,transforming the unstable state into a stable state,and vice versa.These findings offer valuable insights and a theoretical foundation for improving the performance of real-world networks,such as communication networks,biological systems,and social networks,where noise is often inevitable.展开更多
This study investigates chaotic synchronization via field-coupled nonlinear circuits, achieving both electrical synchronization and energy balance. The driving mechanism biomimetically parallels neuromuscular signal t...This study investigates chaotic synchronization via field-coupled nonlinear circuits, achieving both electrical synchronization and energy balance. The driving mechanism biomimetically parallels neuromuscular signal transduction, where synchronized neuronal firing induces coordinated muscle contractions that produce macroscopic movement. We implement a Chua circuit-driven robotic arm with tunable periodic/chaotic oscillations through parameter modulation and external current injection. Bifurcation analysis maps oscillation modes under varying external stimuli. Inductive coupling between two systems with distinct initial conditions facilitates magnetic energy transfer, optimized by an energy balance criterion. A bio-inspired exponential gain method dynamically regulates the coupling strength to optimize the energy transfer efficiency.The effects of ambient electromagnetic noise on synchronization are systematically quantified. The results indicate electrically modulatable robotic arm dynamics, with the coupled systems achieving autonomous rapid synchronization. Despite noise-induced desynchronization, inter-system errors rapidly decay and stabilize within bounded limits, confirming robust stability.展开更多
This paper deeply introduces a brand-new research method for the synchronous characteristics of DC microgrid bus voltage and an improved synchronous control strategy.This method mainly targets the problem of bus volta...This paper deeply introduces a brand-new research method for the synchronous characteristics of DC microgrid bus voltage and an improved synchronous control strategy.This method mainly targets the problem of bus voltage oscillation caused by the bifurcation behavior of DC microgrid converters.Firstly,the article elaborately establishes a mathematical model of a single distributed power source with hierarchical control.On this basis,a smallworld network model that can better adapt to the topology structure of DC microgrids is further constructed.Then,a voltage synchronization analysis method based on the main stability function is proposed,and the synchronous characteristics of DC bus voltage are deeply studied by analyzing the size of the minimum non-zero eigenvalue.In view of the situation that the line coupling strength between distributed power sources is insufficient to achieve bus voltage synchronization,this paper innovatively proposes a new improved adaptive controller to effectively control voltage synchronization.And the convergence of the designed controller is strictly proved by using Lyapunov’s stability theorem.Finally,the effectiveness and feasibility of the designed controller in this paper are fully verified through detailed simulation experiments.After comparative analysis with the traditional adaptive controller,it is found that the newly designed controller can make the bus voltages of each distributed power source achieve synchronization more quickly,and is significantly superior to the traditional adaptive controller in terms of anti-interference performance.展开更多
BACKGROUND Cardiac myxoma is a benign neoplasm and one of the most common types of primary cardiac tumors.Synchronous cardiac myxoma and other malignancies are extremely rare,and only limited cases have been reported....BACKGROUND Cardiac myxoma is a benign neoplasm and one of the most common types of primary cardiac tumors.Synchronous cardiac myxoma and other malignancies are extremely rare,and only limited cases have been reported.CASE SUMMARY We describe a young patient with newly diagnosed locally advanced laryngeal cancer,with a synchronous cardiac tumor detected on staging scans.An echocar-diogram showed the typical appearance of myxoma in the left atrium.Early cardiac surgery was performed in view of its obstructive features and post cardiac surgery recovery was uneventful.The patient was scheduled for subsequent oncological treatment for the laryngeal cancer.However,due to rapid progression of the advanced laryngeal malignancy,he was placed on supportive care.CONCLUSION To our knowledge,this is the first reported case of synchronous cardiac myxoma with laryngeal malignancy.Individualized treatment strategy should be adopted to manage synchronous tumors in a multidisciplinary approach.The most life-threatening condition needs be treated first.Single resection,staged operations or simultaneous resection of both tumors have been reported with good outcomes.展开更多
This paper investigates the problem of cluster synchronization of master-slave complex net-works with time-varying delay via linear and adaptive feedback pinning controls.We need not non-delayed and delayed coupling m...This paper investigates the problem of cluster synchronization of master-slave complex net-works with time-varying delay via linear and adaptive feedback pinning controls.We need not non-delayed and delayed coupling matrices to be symmetric or irreducible.We have the advantages of using adaptive control method to reduce control gain and pinning control technology to reduce cost.By con-structing Lyapunov function,some sufficient synchronization criteria are established.Finally,numerical examples are employed to illustrate the effectiveness of the proposed approach.展开更多
The blisk is a core component of an aero-engine,and electrochemical machining(ECM)is the primary method for its manufacture.Among several ECM methods for blisks,multi-tool synchronous machining is the most efficient a...The blisk is a core component of an aero-engine,and electrochemical machining(ECM)is the primary method for its manufacture.Among several ECM methods for blisks,multi-tool synchronous machining is the most efficient and advantageous for machining channels.The allowance distribution of the blank after blisk channel machining directly influences the blade profile accuracy.This paper proposes a trajectory control strategy to homogenize the allowance distribution of the blisk channel in multi-tool ECM.The strategy includes the design of the three-dimensional space motion of the tool and blisk,as well as the regulated feed speed.The structural characteristics of the blisk channel and the principle of ECM allow for designing and optimizing the multidimensional trajectory.The electric field simulations elucidate the influence law of the three-axis feed speed on the side gap.An algorithm is adopted to iteratively optimize the speeds for different positions to realize multi-dimensional motion control and allowance homogenization.The proposed trajectory control strategy is applied to ECM experiments for the blisk channel.Compared with the constant feed speed mode,the regulated speed strategy reduces the maximum allowance difference between the convex(CV)profiles by 36.18%and that between the concave(CC)profiles by 37.73%.Subsequently,the one-time ECM of eight blisk channels was successfully realized.The average time for a single channel was 12.5 min,significantly improving the machining efficiency.In conclusion,the proposed method is effective and can be extended for synchronously machining various blisk types with twisted channels.展开更多
Complex networks play a crucial role in the study of collective behavior,encompassing the analysis of dynamical properties and network topology.In real-world systems,higher-order interactions among multiple entities a...Complex networks play a crucial role in the study of collective behavior,encompassing the analysis of dynamical properties and network topology.In real-world systems,higher-order interactions among multiple entities are widespread and significantly influence collective dynamics.Here,we extend the synchronization alignment function framework to hypergraphs of arbitrary order by leveraging the multi-order Laplacian matrix to encode higher-order interactions.Our findings reveal that the upper bound of synchronous behavior is determined by the maximum eigenvalue of the multi-order Laplacian matrix.Furthermore,we decompose the contribution of each hyperedge to this eigenvalue and utilize it as a basis for designing an eigenvalue-based topology modification algorithm.This algorithm effectively enhances the upper bound of synchronous behavior without altering the total number of higher-order interactions.Our study provides new insights into dynamical optimization and topology tuning in hypergraphs,advancing the understanding of the interplay between higher-order interactions and collective dynamics.展开更多
This study proposes a novel time-synchronization protocol inspired by stochastic gradient algorithms.The clock model of each network node in this synchronizer is configured as a generic adaptive filter where different...This study proposes a novel time-synchronization protocol inspired by stochastic gradient algorithms.The clock model of each network node in this synchronizer is configured as a generic adaptive filter where different stochastic gradient algorithms can be adopted for adaptive clock frequency adjustments.The study analyzes the pairwise synchronization behavior of the protocol and proves the generalized convergence of the synchronization error and clock frequency.A novel closed-form expression is also derived for a generalized asymptotic error variance steady state.Steady and convergence analyses are then presented for the synchronization,with frequency adaptations done using least mean square(LMS),the Newton search,the gradient descent(GraDes),the normalized LMS(N-LMS),and the Sign-Data LMS algorithms.Results obtained from real-time experiments showed a better performance of our protocols as compared to the Average Proportional-Integral Synchronization Protocol(AvgPISync)regarding the impact of quantization error on synchronization accuracy,precision,and convergence time.This generalized approach to time synchronization allows flexibility in selecting a suitable protocol for different wireless sensor network applications.展开更多
While laser surface texturing(LST)is a promising manufacturing technique for surface functionalization,simultaneously realizing high precision and high efficiency in the LST of complex curved surface is challenging,du...While laser surface texturing(LST)is a promising manufacturing technique for surface functionalization,simultaneously realizing high precision and high efficiency in the LST of complex curved surface is challenging,due to continuously varied geometries of laser-matter incidence.In the present work,we propose a novel manufacturing system of 7-axis on-the-fly LST for complex curved surface,based on the integrated synchronization of 5-axis linkage motion platform with 2-axis galvanometer.Specifically,the algorithm for decomposing spatial texture trajectory on curved surface into low-frequency and high-frequency parts is established,based on which the kinematic model of synchronized 7-axis system is developed to derive the motion of each axis in both 5-axis linkage motion platform and 2-axis galvanometer simultaneously.Subsequently,the synchronized 7-axis LST system is experimentally realized,including the setup of mechanical stages integrated with optical path,the configuration of numerical control unit,and the development of processing software.Finally,case study of 7-axis on-the-fly LST of freeform aluminum surface is performed,and the advantages in terms of processing efficiency and texturing accuracy over 5-axis linkage LST are demonstrated.The correlation of reduced following errors between mechanical stages with the promoted performance of curved surface texturing by the 7-axis on-the-fly LST is further analyzed.Current work provides a feasible solution for establishing the manufacturing system for high performance LST of complex curved surface.展开更多
Background Pigs fed diets with different ingredients but identical nutritional levels show significant differences in growth performance,indicating that growth may also be influenced by the synchronicity of dietary ca...Background Pigs fed diets with different ingredients but identical nutritional levels show significant differences in growth performance,indicating that growth may also be influenced by the synchronicity of dietary carbon and nitrogen supply.Therefore,this study aimed to determine glucose release kinetics of various feed ingredients,to investigate a glucose release pattern that is conducive to synchronized carbon–nitrogen supply,and to elucidate the underlying mechanisms by which this synchronization optimizes growth of pigs.Results We analyzed the glucose release kinetics of 23 feed ingredients in vitro and found that their glucose release rates and amounts varied greatly.Based on this,a nitrogen-free diet and 5 purified diets,which represented the observed variations in glucose release rates and quantities among feed ingredients,were designed for 18 ileal-cannulated pigs.The results demonstrated that slower glucose release pattern could disrupt the synchrony of dietary carbon and nitrogen supply,reducing the growth of pigs and increasing nitrogen losses.Specifically,the diet with slower and moderate amounts of glucose release showed a relatively slower release of amino acids.Pigs fed this diet had the lower amino acid digestibility and the enrichment of harmful bacteria,such as Streptococcus,in the terminal ileum.Conversely,the diets with slower and lower glucose release exhibited a relatively rapid release of amino acids but also resulted in poor growth.They increased glucogenic amino acid digestibility and potentially enriched bacteria involved in nitrogen cycling and carbon metabolism.Notably,only the diet with rapid glucose release achieved synchronized and rapid release of nutrients.Pigs fed this diet exhibited higher amino acid digestibility,decreased harmful bacteria enrichment,improved nutrient utilization,and enhanced short-term growth performance.Conclusions Our research analyzed significant differences in glucose release kinetics among swine feed ingredients and revealed that slow glucose release disrupted dietary carbon–nitrogen supply synchrony,shifting amino acid utilization and enriching pathogens,negatively impacting growth and nutrient utilization.Consequently,choosing feed ingredients releasing glucose at a rapid rate to balance dietary carbon and nitrogen supply helps promote pig growth,and ensures efficient feed utilization.展开更多
基金Supported by the National Natural Science Foundation of China(12301577)Sichuan Science and Technology Program(2023NSFSC1346).
文摘In this paper,the synchronizable system by groups and the generalized synchronizable system are studied for a coupled system of wave equations.Moreover,situations possessing different groupings are also discussed.
基金supported by the National Natural Science Foundation of China(No.52174184)。
文摘This paper propose a comprehensive data-driven prediction framework based on machine learning methods to investigate the lag synchronization phenomenon in coupled chaotic systems,particularly in cases where accurate mathematical models are challenging to establish or where system equations remain unknown.The Long Short-Term Memory(LSTM)neural network is trained using time series acquired from the desynchronization system states,subsequently predicting the lag synchronization transition.In the experiments,we focus on the Lorenz system with time-varying delayed coupling,studying the effects of coupling coefficients and time delays on lag synchronization,respectively.The results indicate that with appropriate training,the machine learning model can adeptly predict the lag synchronization occurrence and transition.This study not only enhances our comprehension of complex network synchronization behaviors but also underscores the potential and practical applications of machine learning in exploring nonlinear dynamic systems.
基金supported in part by the National Natural Science Foundation of China(62033005,62273270)the Natural Science Foundation of Shaanxi Province(2023JC-XJ17)
文摘Dear Editor,This letter proposes a deep synchronization control(DSC) method to synchronize grid-forming converters with power grids. The method involves constructing a novel controller for grid-forming converters based on the stable deep dynamics model. To enhance the performance of the controller, the dynamics model is optimized within the deep reinforcement learning(DRL) framework. Simulation results verify that the proposed method can reduce frequency deviation and improve active power responses.
基金Hong Kong Research Grants Council under the GRF(9043664).
文摘This article briefly reviews the topic of complex network synchronization,with its graph-theoretic criterion,showing that the homogeneous and symmetrical network structures are essential for optimal synchronization.Furthermore,it briefly reviews the notion of higher-order network topologies and shows their promising potential in application to evaluating the optimality of network synchronizability.
基金funded by Sponsorship of Science and Technology Project of State Grid Xinjiang Electric Power Co.,Ltd.,grant number SGXJ0000TKJS2400168.
文摘This study presents an emergency control method for sub-synchronous oscillations in wind power gridconnected systems based on transfer learning,addressing the issue of insufficient generalization ability of traditional methods in complex real-world scenarios.By combining deep reinforcement learning with a transfer learning framework,cross-scenario knowledge transfer is achieved,significantly enhancing the adaptability of the control strategy.First,a sub-synchronous oscillation emergency control model for the wind power grid integration system is constructed under fixed scenarios based on deep reinforcement learning.A reward evaluation system based on the active power oscillation pattern of the system is proposed,introducing penalty functions for the number of machine-shedding rounds and the number of machines shed.This avoids the economic losses and grid security risks caused by the excessive one-time shedding of wind turbines.Furthermore,transfer learning is introduced into model training to enhance the model’s generalization capability in dealing with complex scenarios of actual wind power grid integration systems.By introducing the Maximum Mean Discrepancy(MMD)algorithm to calculate the distribution differences between source data and target data,the online decision-making reliability of the emergency control model is improved.Finally,the effectiveness of the proposed emergency control method for multi-scenario sub-synchronous oscillation in wind power grid integration systems based on transfer learning is analyzed using the New England 39-bus system.
基金Supported by the National Natural Science Foundation of China (11161027)。
文摘Projective synchronization problems of a drive system and a particular response network were investigated,where the drive system is an arbitrary system with n+1 dimensions;it may be a linear or nonlinear system,and even a chaotic or hyperchaotic system,the response network is complex system coupled by N nodes,and every node is showed by the approximately linear part of the drive system.Only controlling any one node of the response network by designed controller can achieve the projective synchronization.Some numerical examples were employed to verify the effectiveness and correctness of the designed controller.
文摘Permanent magnet synchronous motor(PMSM),known for their compact size and high-power density,is widely used in fields such as electric vehicles and servo drives.However,traditional PID control methods for PMSM cannot dynamically adjust parameters according to varying operating conditions.To address this issue,this paper proposes a PID control method based on a radial basis function(RBF)neural network,which adaptively tunes the PID controller parameters.First,an offline RBF neural network with optimal structural parameters is trained using the current and speed data of the PMSM,and then employed to construct the RBF-PID controller.During online training,the Jacobian information calculated via the RBF neural network is used to adaptively adjust the PID parameters.Simultaneously,the structural parameters of the RBF network are updated in reverse based on the error between the predicted and reference speed values.Finally,numerical simulations and experiments in the context of electric vehicle drive control show that the maximum speed errors of the SMC controller and the RBF-PID controller are 1.97 km/h and 0.17 km/h,respectively.Moreover,the RBF-PID controller outperforms both the SMC and traditional PID controllers in handling sudden speed changes.
基金supported by the Innovation Program for Quantum Science and Technology(Grant Nos.2021ZD0301200,2021ZD0303200,and 2021ZD0301500)the Alliance of International Science Organizations(ANSO)。
文摘Recently,large-scale trapped ion systems have been realized in experiments for quantum simulation and quantum computation.They are the simplest systems for dynamical stability and parametric resonance.In this model,the Mathieu equation plays the most fundamental role for us to understand the stability and instability of a single ion.In this work,we investigate the dynamics of trapped ions with the Coulomb interaction based on the Hamiltonian equation.We show that the many-body interaction will not influence the phase diagram for instability.Then,the dynamics of this model in the large damping limit will also be analytically calculated using few trapped ions.Furthermore,we find that in the presence of modulation,synchronization dynamics can be observed,showing an exchange of velocities between distant ions on the left side and on the right side of the trap.These dynamics resemble that of the exchange of velocities in Newton's cradle for the collision of balls at the same time.These dynamics are independent of their initial conditions and the number of ions.As a unique feature of the interacting Mathieu equation,we hope this behavior,which leads to a quasi-periodic solution,can be measured in current experimental systems.Finally,we have also discussed the effect of anharmonic trapping potential,showing the desynchronization during the collision process.It is hoped that the dynamics in this many-body Mathieu equation with damping may find applications in quantum simulations.This model may also find interesting applications in dynamics systems as a pure mathematical problem,which may be beyond the results in the Floquet theorem.
基金Supported by the National Natural Science Foundation of China(62476082)。
文摘This paper investigates modified fixed-time synchronization(FxTS)of complex networks(CNs)with time-varying delays based on continuous and discontinuous controllers.First,for the sake of making the settling time(ST)of FxTS is independent of the initial values and parameters of the CNs,a modified fixed-time(FxT)stability theorem is proposed,where the ST is determined by an arbitrary positive number given in advance.Then,continuous controller and discontinuous controller are designed to realize the modified FxTS target of CNs.In addition,based on the designed controllers,CNs can achieve synchronization at any given time,or even earlier.And control strategies effectively solve the problem of ST related to the parameters of CNs.Finally,an appropriate simulation example is conducted to examine the effectiveness of the designed control strategies.
基金supported by National Key R&D Program of China under Grants No.2022YFB3902500,No.2022YFB2903402,and No.2021YFA0718804Natural Science Foundation of Jilin Province under Grant No.222621JC010297013Education Department of Jilin Province under Grant No.JJKH20220745KJ.
文摘Optical wireless(OW)communication systems face significant challenges such as signal attenuation due to atmospheric absorption,scattering,and noise from hardware components,which degrade detection sensitivity.To address these challenges,we propose a digital processing algorithm that combines finite impulse response filtering with dynamic synchronization based on pulse addition and subtraction.Unlike conventional methods,which typically rely solely on hardware optimization or basic thresholding techniques,the proposed approach integrates filtering and synchronization to improve weak signal detection and reduce noise-induced errors.The proposed algorithm was implemented and verified using a field-programmable gate array.Experiments conducted in an indoor OW communication environment demonstrate that the proposed algorithm significantly improves detection sensitivity by approximately 6 dB and 5 dB at communication rates of 3.5 Mbps and 5.0 Mbps,respectively.Specifically,under darkroom conditions and a bit error rate of 1×10^(-7),the detection sensitivity was improved from-38.56 dBm to-44.77 dBm at 3.5 Mbps and from-37.12 dBm to-42.29 dBm at 5 Mbps.The proposed algorithm is crucial for future capture and tracking of signals at large dispersion angles and in underwater and long-distance communication scenarios.
基金Project supported in part by the National Natural Science Foundation of China(Grant Nos.62473284,61973064,62203327)Hebei Natural Science Foundation(Grant No.F2022501024)。
文摘This paper explores the synchronization of stochastic simplicial complexes with noise,modeled by stochastic differential equations of It?type.It establishes the relationship between synchronization and individual dynamics,higher-order structures,coupling strengths,and noise.In particular,this study delves into the role of multi-body interactions,particularly focusing on the influence of higher-order simplicial structures on the overall synchronization behavior.Furthermore,the effects of noise on synchronizability in the stochastic simplicial complex are thoroughly examined.The obtained results indicate that the effects of noise on the synchronizability vary with the manner in which noise propagates.The presence of noise can regulate the synchronization pattern of the simplicial complex,transforming the unstable state into a stable state,and vice versa.These findings offer valuable insights and a theoretical foundation for improving the performance of real-world networks,such as communication networks,biological systems,and social networks,where noise is often inevitable.
基金Project supported by the National Key R&D Program of China (Grant No. 2023YFD2000601-02)。
文摘This study investigates chaotic synchronization via field-coupled nonlinear circuits, achieving both electrical synchronization and energy balance. The driving mechanism biomimetically parallels neuromuscular signal transduction, where synchronized neuronal firing induces coordinated muscle contractions that produce macroscopic movement. We implement a Chua circuit-driven robotic arm with tunable periodic/chaotic oscillations through parameter modulation and external current injection. Bifurcation analysis maps oscillation modes under varying external stimuli. Inductive coupling between two systems with distinct initial conditions facilitates magnetic energy transfer, optimized by an energy balance criterion. A bio-inspired exponential gain method dynamically regulates the coupling strength to optimize the energy transfer efficiency.The effects of ambient electromagnetic noise on synchronization are systematically quantified. The results indicate electrically modulatable robotic arm dynamics, with the coupled systems achieving autonomous rapid synchronization. Despite noise-induced desynchronization, inter-system errors rapidly decay and stabilize within bounded limits, confirming robust stability.
基金supported by the National Natural Science Foundation of China(Nos.51767017 and 51867015)the Basic Research and Innovation Group Project of Gansu(No.18JR3RA13)the Major Science and Technology Project of Gansu(No.19ZD2GA003).
文摘This paper deeply introduces a brand-new research method for the synchronous characteristics of DC microgrid bus voltage and an improved synchronous control strategy.This method mainly targets the problem of bus voltage oscillation caused by the bifurcation behavior of DC microgrid converters.Firstly,the article elaborately establishes a mathematical model of a single distributed power source with hierarchical control.On this basis,a smallworld network model that can better adapt to the topology structure of DC microgrids is further constructed.Then,a voltage synchronization analysis method based on the main stability function is proposed,and the synchronous characteristics of DC bus voltage are deeply studied by analyzing the size of the minimum non-zero eigenvalue.In view of the situation that the line coupling strength between distributed power sources is insufficient to achieve bus voltage synchronization,this paper innovatively proposes a new improved adaptive controller to effectively control voltage synchronization.And the convergence of the designed controller is strictly proved by using Lyapunov’s stability theorem.Finally,the effectiveness and feasibility of the designed controller in this paper are fully verified through detailed simulation experiments.After comparative analysis with the traditional adaptive controller,it is found that the newly designed controller can make the bus voltages of each distributed power source achieve synchronization more quickly,and is significantly superior to the traditional adaptive controller in terms of anti-interference performance.
文摘BACKGROUND Cardiac myxoma is a benign neoplasm and one of the most common types of primary cardiac tumors.Synchronous cardiac myxoma and other malignancies are extremely rare,and only limited cases have been reported.CASE SUMMARY We describe a young patient with newly diagnosed locally advanced laryngeal cancer,with a synchronous cardiac tumor detected on staging scans.An echocar-diogram showed the typical appearance of myxoma in the left atrium.Early cardiac surgery was performed in view of its obstructive features and post cardiac surgery recovery was uneventful.The patient was scheduled for subsequent oncological treatment for the laryngeal cancer.However,due to rapid progression of the advanced laryngeal malignancy,he was placed on supportive care.CONCLUSION To our knowledge,this is the first reported case of synchronous cardiac myxoma with laryngeal malignancy.Individualized treatment strategy should be adopted to manage synchronous tumors in a multidisciplinary approach.The most life-threatening condition needs be treated first.Single resection,staged operations or simultaneous resection of both tumors have been reported with good outcomes.
文摘This paper investigates the problem of cluster synchronization of master-slave complex net-works with time-varying delay via linear and adaptive feedback pinning controls.We need not non-delayed and delayed coupling matrices to be symmetric or irreducible.We have the advantages of using adaptive control method to reduce control gain and pinning control technology to reduce cost.By con-structing Lyapunov function,some sufficient synchronization criteria are established.Finally,numerical examples are employed to illustrate the effectiveness of the proposed approach.
基金co-supported by the National Natural Science Foundation of China(No.52075253)the National Natural Science Foundation of China for Creative Research Groups(No.51921003)the Industrial Technology Development Program(No.JCKY2021605B026)。
文摘The blisk is a core component of an aero-engine,and electrochemical machining(ECM)is the primary method for its manufacture.Among several ECM methods for blisks,multi-tool synchronous machining is the most efficient and advantageous for machining channels.The allowance distribution of the blank after blisk channel machining directly influences the blade profile accuracy.This paper proposes a trajectory control strategy to homogenize the allowance distribution of the blisk channel in multi-tool ECM.The strategy includes the design of the three-dimensional space motion of the tool and blisk,as well as the regulated feed speed.The structural characteristics of the blisk channel and the principle of ECM allow for designing and optimizing the multidimensional trajectory.The electric field simulations elucidate the influence law of the three-axis feed speed on the side gap.An algorithm is adopted to iteratively optimize the speeds for different positions to realize multi-dimensional motion control and allowance homogenization.The proposed trajectory control strategy is applied to ECM experiments for the blisk channel.Compared with the constant feed speed mode,the regulated speed strategy reduces the maximum allowance difference between the convex(CV)profiles by 36.18%and that between the concave(CC)profiles by 37.73%.Subsequently,the one-time ECM of eight blisk channels was successfully realized.The average time for a single channel was 12.5 min,significantly improving the machining efficiency.In conclusion,the proposed method is effective and can be extended for synchronously machining various blisk types with twisted channels.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12247153,T2293771,and 12247101)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LTGY24A050002)+3 种基金the Sichuan Science and Technology Program(Grant Nos.2024NSFSC1364 and 2023NSFSC1919)the Project of Huzhou Science and Technology Bureau(Grant No.2022YZ29)the UESTCYDRI research start-up(Grant No.U03210066)the New Cornerstone Science Foundation through the Xplorer Prize。
文摘Complex networks play a crucial role in the study of collective behavior,encompassing the analysis of dynamical properties and network topology.In real-world systems,higher-order interactions among multiple entities are widespread and significantly influence collective dynamics.Here,we extend the synchronization alignment function framework to hypergraphs of arbitrary order by leveraging the multi-order Laplacian matrix to encode higher-order interactions.Our findings reveal that the upper bound of synchronous behavior is determined by the maximum eigenvalue of the multi-order Laplacian matrix.Furthermore,we decompose the contribution of each hyperedge to this eigenvalue and utilize it as a basis for designing an eigenvalue-based topology modification algorithm.This algorithm effectively enhances the upper bound of synchronous behavior without altering the total number of higher-order interactions.Our study provides new insights into dynamical optimization and topology tuning in hypergraphs,advancing the understanding of the interplay between higher-order interactions and collective dynamics.
基金funded by Universiti Putra Malaysia under a Geran Putra Inisiatif(GPI)research grant with reference to GP-GPI/2023/9762100.
文摘This study proposes a novel time-synchronization protocol inspired by stochastic gradient algorithms.The clock model of each network node in this synchronizer is configured as a generic adaptive filter where different stochastic gradient algorithms can be adopted for adaptive clock frequency adjustments.The study analyzes the pairwise synchronization behavior of the protocol and proves the generalized convergence of the synchronization error and clock frequency.A novel closed-form expression is also derived for a generalized asymptotic error variance steady state.Steady and convergence analyses are then presented for the synchronization,with frequency adaptations done using least mean square(LMS),the Newton search,the gradient descent(GraDes),the normalized LMS(N-LMS),and the Sign-Data LMS algorithms.Results obtained from real-time experiments showed a better performance of our protocols as compared to the Average Proportional-Integral Synchronization Protocol(AvgPISync)regarding the impact of quantization error on synchronization accuracy,precision,and convergence time.This generalized approach to time synchronization allows flexibility in selecting a suitable protocol for different wireless sensor network applications.
基金the support by the Harbin Manufacturing Science and Technology Innovation Talent Project(No.2023CXRCGD035)the Open Research Foundation of State Key Laboratory of Digital Manufacturing Equipment and Technology in Huazhong University of Science and Technology,China(No.IMETKF2023012).
文摘While laser surface texturing(LST)is a promising manufacturing technique for surface functionalization,simultaneously realizing high precision and high efficiency in the LST of complex curved surface is challenging,due to continuously varied geometries of laser-matter incidence.In the present work,we propose a novel manufacturing system of 7-axis on-the-fly LST for complex curved surface,based on the integrated synchronization of 5-axis linkage motion platform with 2-axis galvanometer.Specifically,the algorithm for decomposing spatial texture trajectory on curved surface into low-frequency and high-frequency parts is established,based on which the kinematic model of synchronized 7-axis system is developed to derive the motion of each axis in both 5-axis linkage motion platform and 2-axis galvanometer simultaneously.Subsequently,the synchronized 7-axis LST system is experimentally realized,including the setup of mechanical stages integrated with optical path,the configuration of numerical control unit,and the development of processing software.Finally,case study of 7-axis on-the-fly LST of freeform aluminum surface is performed,and the advantages in terms of processing efficiency and texturing accuracy over 5-axis linkage LST are demonstrated.The correlation of reduced following errors between mechanical stages with the promoted performance of curved surface texturing by the 7-axis on-the-fly LST is further analyzed.Current work provides a feasible solution for establishing the manufacturing system for high performance LST of complex curved surface.
基金supported by the National Key Research and Development Program of China(2021YFD1300201)the National Natural Science Foundation of China(32330100 and 32125036)+3 种基金the China Agricultural Research System(CARS-35)2115 Talent Development Program of China Agricultural Universitythe 111 Project(No.B16044)the 2023 Key Project of the Graduate Independent Innovation Research Fund at China Agricultural University。
文摘Background Pigs fed diets with different ingredients but identical nutritional levels show significant differences in growth performance,indicating that growth may also be influenced by the synchronicity of dietary carbon and nitrogen supply.Therefore,this study aimed to determine glucose release kinetics of various feed ingredients,to investigate a glucose release pattern that is conducive to synchronized carbon–nitrogen supply,and to elucidate the underlying mechanisms by which this synchronization optimizes growth of pigs.Results We analyzed the glucose release kinetics of 23 feed ingredients in vitro and found that their glucose release rates and amounts varied greatly.Based on this,a nitrogen-free diet and 5 purified diets,which represented the observed variations in glucose release rates and quantities among feed ingredients,were designed for 18 ileal-cannulated pigs.The results demonstrated that slower glucose release pattern could disrupt the synchrony of dietary carbon and nitrogen supply,reducing the growth of pigs and increasing nitrogen losses.Specifically,the diet with slower and moderate amounts of glucose release showed a relatively slower release of amino acids.Pigs fed this diet had the lower amino acid digestibility and the enrichment of harmful bacteria,such as Streptococcus,in the terminal ileum.Conversely,the diets with slower and lower glucose release exhibited a relatively rapid release of amino acids but also resulted in poor growth.They increased glucogenic amino acid digestibility and potentially enriched bacteria involved in nitrogen cycling and carbon metabolism.Notably,only the diet with rapid glucose release achieved synchronized and rapid release of nutrients.Pigs fed this diet exhibited higher amino acid digestibility,decreased harmful bacteria enrichment,improved nutrient utilization,and enhanced short-term growth performance.Conclusions Our research analyzed significant differences in glucose release kinetics among swine feed ingredients and revealed that slow glucose release disrupted dietary carbon–nitrogen supply synchrony,shifting amino acid utilization and enriching pathogens,negatively impacting growth and nutrient utilization.Consequently,choosing feed ingredients releasing glucose at a rapid rate to balance dietary carbon and nitrogen supply helps promote pig growth,and ensures efficient feed utilization.
