During electric vehicle(EV)-assisted grid frequency modulation,inconsistent state of charge(SOC)among EVs can result in overcharging and discharging of the batteries,affecting the stability of the electrical system.As...During electric vehicle(EV)-assisted grid frequency modulation,inconsistent state of charge(SOC)among EVs can result in overcharging and discharging of the batteries,affecting the stability of the electrical system.As a solution,this paper proposes a priority-based frequency regulation strategy for EVs.Firstly,models for the primary and secondary frequency regulation of EV-assisted power grids are established.Secondly,a consensus algorithm is used to construct a distributed com-munication system for EVs.Target SOC values are used to obtain a local frequency regulation priori-ty list.The list is used in an optimal control plan allowing individual EVs to participate in frequency regulation.Finally,a simulation of this strategy under several scenarios is conducted.The results indicate that the strategy ensures uniform SOC among the participating group of EVs,thereby avoi-ding overcharging and discharging of their batteries.It also reduces frequency fluctuations in the electrical system,making the system more robust compared with the frequency regulation strategy that is not priority-based.展开更多
The dynamics of complex gene regulation systems can be simulated by the Gillespie algorithm. The classic Gillespie algorithm is appropriate to simulate a stochastic
This paper sets Chaihu Town, Zhongxiang City of Hubei Province as an example, analyzing the ecological and hydrological conditions of Chaihu Town, applying LID （low impact development） mode and putting forward the e...This paper sets Chaihu Town, Zhongxiang City of Hubei Province as an example, analyzing the ecological and hydrological conditions of Chaihu Town, applying LID （low impact development） mode and putting forward the ecological stormwater regulation system planning strategy which adapts to the development of small towns. The main conclusions are as follows： （1） The ＂three-low＂ development mode is put forward, which means low impact, low cost and low carbon, using this construction mode to minimize the ecological impact, relying on natural green space and water to achieve the function of rainstorm regulation; （2） Through the analysis and calculation of the local amount of precipitation, this paper scientifically calculates the required area of storage water and green space, taking the roads as trunks, green spaces as stems, water as veins, and building the green infrastructure system; （3） The author has been repairing and integrating the original drainage ditches of the planning area, replacing traditional rain drainage pipes, establishing ＂two-loop＂ water network system which aims at the detention and purification of rainwater, maximizing ecological benefit, economic benefit and landscape benefit.展开更多
After the new round of restructuring of Chinese telecom sector,it's pressing to formulate and implement asymmetric regulation policies so as to shape an effectively competitive market structure in a relatively sho...After the new round of restructuring of Chinese telecom sector,it's pressing to formulate and implement asymmetric regulation policies so as to shape an effectively competitive market structure in a relatively short term.This paper reviewed the asymmetric regulation policies and practices carried out in foreign telecom market,and then according to the specific situations of Chinese telecom market,proposed the principles and corresponding policies for establishing an asymmetric regulation system fit for Chinese telecom market.展开更多
Outlined the South African mine health and safety regulatory framework,in- cluding the roles of government,tripartite council,service agencies,mine enterprises, rescue stations and workers unions,analyzed the institut...Outlined the South African mine health and safety regulatory framework,in- cluding the roles of government,tripartite council,service agencies,mine enterprises, rescue stations and workers unions,analyzed the institutional structures of South African mine health and safety standardization,including the South African standard and specifi- cation systems and standard development processes,and characterized the South African mine health and safety standardization and regulation systems.Intended to provide some suggestions for the transformation and improvement of mine health and safety standardi- zation and regulation systems in China or in similar situations.展开更多
Main Exhauster is one of the main equipment of sintering production. It needs to consume a lot of electricity. Therefore, the system＇ s reconstruction for energy-saving will effectively reduce electricity for the pro...Main Exhauster is one of the main equipment of sintering production. It needs to consume a lot of electricity. Therefore, the system＇ s reconstruction for energy-saving will effectively reduce electricity for the production. The paper takes an iron and steel enterprise that had successfully transformed the synchronous motors of main exhauster of sintering as an example, which describes the application of high-voltage variable frequency speed regulation system in main exhauster of Sintering, so as to provide a reference for other iron and steel enterprises.展开更多
This paper presents the solution of regulating the wind rate automatically by means of fuzzy control technology and implementing it with PLC (programmable logical controller) under the circumstance of many influence f...This paper presents the solution of regulating the wind rate automatically by means of fuzzy control technology and implementing it with PLC (programmable logical controller) under the circumstance of many influence factors, which exists in the axial flow fans wind rate regulation system during the process of mine ventilation, and has difficulty in modifying the mathematic model to obtain the satisfied result by normal control ways. According to this analysis, the intelligent and analytic treatment of fuzzy controller has been made and fuzzy control scheme involving self regulation divisor and intelligent integral has been deeply proposed. Test result shows that this system based on the scheme above is obviously prior to others in its responsibility such as high speed, overshoot, control precision and robustness. The system furnishes the great reliability of mine working safety and fans running efficiency.展开更多
In order to scientifically deal with the problems of less water and more sediment in the Yellow River and the uncoordinated relationship between water and sediment,it is necessary to establish a perfect water and sedi...In order to scientifically deal with the problems of less water and more sediment in the Yellow River and the uncoordinated relationship between water and sediment,it is necessary to establish a perfect water and sediment regulation system.Through the calculation of the sediment transport capacity of the Yellow River and the application of the water and sediment regulation system,it is found that the sediment transport efficiency of the Yellow River will increase with the increase of water flow,and there will be an obvious inflection point near the flat discharge.The joint regulation of the backbone reservoir group can discharge the large discharge close to the minimum flat discharge of the downstream river,which improves the sediment transport capacity of the river and alleviates the problem of sediment deposition.In this paper,through the introduction of the Yellow River water and sediment regulation project system,regulation indicators and mechanisms,the author discusses in detail the Yellow River water and sediment regulation scheme and its operation effect,hoping to provide help promote the improvement of the Yellow River governance effect.展开更多
Dear Editor,This letter focuses on the distributed cooperative regulation problem for a class of networked re-entrant manufacturing systems(RMSs).The networked system is structured with a three-tier architecture:the p...Dear Editor,This letter focuses on the distributed cooperative regulation problem for a class of networked re-entrant manufacturing systems(RMSs).The networked system is structured with a three-tier architecture:the production line,the manufacturing layer and the workshop layer.The dynamics of re-entrant production lines are governed by hyperbolic partial differential equations(PDEs)based on the law of mass conservation.展开更多
Amid ongoing global environmental change and the critical pursuit of sustainable development,human-environment systems are exhibiting increasingly complex dynamic evolutions and spatial relationships,underscoring an u...Amid ongoing global environmental change and the critical pursuit of sustainable development,human-environment systems are exhibiting increasingly complex dynamic evolutions and spatial relationships,underscoring an urgent need for innovative research frameworks.Integrated geography synthesizes physical geography,human geography,and geographic information science,providing key frameworks for understanding complex human-environment systems.This editorial proposes an emerging research framework for integrated geography—“Composite driving-System evolution-Coupling mechanism-Synergistic regulation(CSCS)”—based on key issues such as climate change,biodiversity loss,resource scarcity,and social-ecological interactions,which have been highlighted in both recent critical literature on human-environment systems and UN assessment reports.The framework starts with diverse composite driving forces,extends to the evolution of human-environment system structures,processes,and functions that these drivers induce,explores couplings within human-environment systems,and calls for regulation aimed at sustainable development in synergies.Major research frontiers include understanding the cascading“evolution-coupling”effects of shocks;measuring system resilience,thresholds,and safe and just operating space boundaries;clarifying linkage mechanisms across scales;and achieving synergistic outcomes for multi-objective sustainability.This framework will help promote the interdisciplinary integration and development of integrated geography,and provide geographical solutions for the global sustainable development agenda.展开更多
This paper investigates the issue of load disturbances in DC motor speed regulation systems.In response to the limited disturbance rejection capability of traditional PID controllers,a PID controller with feedforward ...This paper investigates the issue of load disturbances in DC motor speed regulation systems.In response to the limited disturbance rejection capability of traditional PID controllers,a PID controller with feedforward compensation is designed.The study first analyzes the dynamic impact mechanism of sudden load changes on motor speed,and then achieves precise control of the DC motor using PWM technology.Through comparative analysis of simulation and experimental results,the proposed feedforward-compens ated PID control demonstrates significant improvements in dynamic response speed,overshoot,and steady-state accuracy compared to traditional PID control.The findings indicate that the proposed control strategy effectively supp resses load disturbances,e nhances system stability and robustness,and offers valuable insights for practical engineering applications.展开更多
Large-scale new energy grid connection leads to the weakening of the system frequency regulation capability,and the system frequency stability is facing unprecedented challenges.In order to solve rapid frequency fluct...Large-scale new energy grid connection leads to the weakening of the system frequency regulation capability,and the system frequency stability is facing unprecedented challenges.In order to solve rapid frequency fluctuation caused by new energy units,this paper proposes a new energy power system frequency regulation strategy with multiple units including the doubly-fed pumped storage unit(DFPSU).Firstly,based on the model predictive control(MPC)theory,the state space equations are established by considering the operating characteristics of the units and the dynamic behavior of the system;secondly,the proportional-differential control link is introduced to minimize the frequency deviation to further optimize the frequency modulation(FM)output of the DFPSU and inhibit the rapid fluctuation of the frequency;lastly,it is verified on theMatlab/Simulink simulation platform,and the results show that the model predictive control with proportional-differential control link can further release the FM potential of the DFPSU,increase the depth of its FM,effectively reduce the frequency deviation of the system and its rate of change,realize the optimization of the active output of the DFPSU and that of other units,and improve the frequency response capability of the system.展开更多
To ensure system stability,the fixed-PID(F-PID)controller with small parameters is usually adopted in hydropower stations.This involves a slow setting speed and it is difficult to realize optimal control for full work...To ensure system stability,the fixed-PID(F-PID)controller with small parameters is usually adopted in hydropower stations.This involves a slow setting speed and it is difficult to realize optimal control for full working conditions.To address the problem,this paper designs a variable-PID(V-PID)controller for a hydraulic turbine regulation system(HTRS)based on the improved grey wolf optimizer(INGWO)and back propagation neural networks(BPNN).These can achieve excellent regulation under full working conditions.First,the nonlinear HTRS model containing the nonlinear hydroturbine model is constructed and the stable domain is obtained using Hopf bifurcation theory to determine the available range of PID parameters.The optimal PID parameters in typical working conditions are then calculated by the INGWO,and the optimal PID parameters are generalized through training the V-PID neural networks which take the optimal PID parameters as sample data.The V-PID neural networks with different structures are compared to determine the optimal structure of the variable-PID controller model.The V-PID controller-based nonlinear HTRS model shows that the PID parameters can be automatically adjusted online according to the working condition changes,realizing optimal control of hydropower units in full working conditions.展开更多
Understanding the influencing factors and the evolving trends of the Water-Sediment Regulation System(WSRS)is vital for the protection and management of the Yellow River.Past studies on WSRS have been limited in focus...Understanding the influencing factors and the evolving trends of the Water-Sediment Regulation System(WSRS)is vital for the protection and management of the Yellow River.Past studies on WSRS have been limited in focus and have not fully addressed the complete engineering control system of the basin.This study takes a holistic view,treating sediment management in the Yellow River as a dynamic and ever-evolving complex system.It merges concepts from system science,information theory,and dissipative structure with practical efforts in sediment engineering control.The key findings of this study are as follows:between 1990 and 2019,the average Yellow River Sediment Regulation Index(YSRI)was 55.99,with the lowest being 50.26 in 1990 and the highest being 61.48 in 2019;the result indicates that the WSRS activity decreased,yet it fluctuated,gradually approaching the critical threshold of a dissipative structure.展开更多
The global shift towards sustainable food systems has sparked innovations in food sources and production systems,including cell-based meat,plant-based food products,precision fermentation,and 3D food printing.These ad...The global shift towards sustainable food systems has sparked innovations in food sources and production systems,including cell-based meat,plant-based food products,precision fermentation,and 3D food printing.These advancements pose regulatory challenges and opportunities,with China emerging as a critical player in adopting and regulating new food technologies.This review explores the international landscape of new food sources and production systems(NFPS),focusing on China’s role and regulatory approaches compared to global practices.Through this comparative analysis,we aim to contribute to the ongoing dialogue on food safety regulation,offering insights and recommendations for policymakers,industry stakeholders,and researchers engaged in the global food system’s evolution.This comprehensive overview underscores the dynamic nature of regulatory frameworks governing NFPS,highlighting the international efforts to ensure food safety,consumer protection,and the sustainable evolution of the food industry.展开更多
This article studies the adaptive optimal output regulation problem for a class of interconnected singularly perturbed systems(SPSs) with unknown dynamics based on reinforcement learning(RL).Taking into account the sl...This article studies the adaptive optimal output regulation problem for a class of interconnected singularly perturbed systems(SPSs) with unknown dynamics based on reinforcement learning(RL).Taking into account the slow and fast characteristics among system states,the interconnected SPS is decomposed into the slow time-scale dynamics and the fast timescale dynamics through singular perturbation theory.For the fast time-scale dynamics with interconnections,we devise a decentralized optimal control strategy by selecting appropriate weight matrices in the cost function.For the slow time-scale dynamics with unknown system parameters,an off-policy RL algorithm with convergence guarantee is given to learn the optimal control strategy in terms of measurement data.By combining the slow and fast controllers,we establish the composite decentralized adaptive optimal output regulator,and rigorously analyze the stability and optimality of the closed-loop system.The proposed decomposition design not only bypasses the numerical stiffness but also alleviates the high-dimensionality.The efficacy of the proposed methodology is validated by a load-frequency control application of a two-area power system.展开更多
This paper investigates the robust cooperative output regulation problem for a class of heterogeneousuncertain linear multi-agent systems with an unknown exosystem via event-triggered control (ETC). By utilizingthe in...This paper investigates the robust cooperative output regulation problem for a class of heterogeneousuncertain linear multi-agent systems with an unknown exosystem via event-triggered control (ETC). By utilizingthe internal model approach and the adaptive control technique, a distributed adaptive internal model isconstructed for each agent. Then, based on this internal model, a fully distributed ETC strategy composed ofa distributed event-triggered adaptive output feedback control law and a distributed dynamic event-triggeringmechanism is proposed, in which each agent updates its control input at its own triggering time instants. It isshown that under the proposed ETC strategy, the robust cooperative output regulation problem can be solvedwithout requiring either the global information associated with the communication topology or the bounds ofthe uncertain or unknown parameters in each agent and the exosystem. A numerical example is provided toillustrate the effectiveness of the proposed control strategy.展开更多
To address the scheduling problem involving energy storage systems and uncertain energy,we propose a method based on multi-stage robust optimization.This approach aims to regulate the energy storage system by using a ...To address the scheduling problem involving energy storage systems and uncertain energy,we propose a method based on multi-stage robust optimization.This approach aims to regulate the energy storage system by using a multi-stage robust optimal control method,which helps overcome the limitations of traditional methods in terms of time scale.The goal is to effectively utilize the energy storage power station system to address issues caused by unpredictable variations in environmental energy and fluctuating load throughout the day.To achieve this,a mathematical model is constructed to represent uncertain energy sources such as photovoltaic and wind power.The generalized Benders Decomposition method is then employed to solve the multi-stage objective optimization problem.By decomposing the problem into a series of sub-objectives,the system scale is effectively reduced,and the algorithm’s convergence ability is improved.Compared with other algorithms,the multi-stage robust optimization model has better economy and convergence ability and can be used to guide the power dispatching of uncertain energy and energy storage systems.展开更多
With the increasing complexity of the current electromagnetic environment,excessive microwave radi-ation not only does harm to human health but also forms various electromagnetic interference to so-phisticated electro...With the increasing complexity of the current electromagnetic environment,excessive microwave radi-ation not only does harm to human health but also forms various electromagnetic interference to so-phisticated electronic instruments.Therefore,the design and preparation of electromagnetic absorbing composites represent an efficient approach to mitigate the current hazards of electromagnetic radiation.However,traditional electromagnetic absorbers are difficult to satisfy the demands of actual utilization in the face of new challenges,and emerging absorbents have garnered increasing attention due to their structure and performance-based advantages.In this review,several emerging composites of Mxene-based,biochar-based,chiral,and heat-resisting are discussed in detail,including their synthetic strategy,structural superiority and regulation method,and final optimization of electromagnetic absorption ca-pacity.These insights provide a comprehensive reference for the future development of new-generation electromagnetic-wave absorption composites.Moreover,the potential development directions of these emerging absorbers have been proposed as well.展开更多
Chlorophyll degradation and carotenoid accumulation are essential processes of fruit maturation in many horticultural plants,and play a crucial role in fruit color and quality.The pathways of chlorophyll and carotenoi...Chlorophyll degradation and carotenoid accumulation are essential processes of fruit maturation in many horticultural plants,and play a crucial role in fruit color and quality.The pathways of chlorophyll and carotenoid biosynthesis and degradation are well understood,and key regulatory genes controlling these pathways have been identified in citrus.This article reviewed the recent research on chlorophyll and carotenoid metabolism in citrus fruits,encompassing the metabolic pathways,transcriptional regulation,influencing factors,and the interplay between chlorophyll and carotenoid metabolism,aiming to provide insights into the molecular regulatory mechanisms governing the coloration of citrus fruits.展开更多
基金Supported by the China Postdoctoral Science Foundation(No.2022M710039).
文摘During electric vehicle(EV)-assisted grid frequency modulation,inconsistent state of charge(SOC)among EVs can result in overcharging and discharging of the batteries,affecting the stability of the electrical system.As a solution,this paper proposes a priority-based frequency regulation strategy for EVs.Firstly,models for the primary and secondary frequency regulation of EV-assisted power grids are established.Secondly,a consensus algorithm is used to construct a distributed com-munication system for EVs.Target SOC values are used to obtain a local frequency regulation priori-ty list.The list is used in an optimal control plan allowing individual EVs to participate in frequency regulation.Finally,a simulation of this strategy under several scenarios is conducted.The results indicate that the strategy ensures uniform SOC among the participating group of EVs,thereby avoi-ding overcharging and discharging of their batteries.It also reduces frequency fluctuations in the electrical system,making the system more robust compared with the frequency regulation strategy that is not priority-based.
文摘The dynamics of complex gene regulation systems can be simulated by the Gillespie algorithm. The classic Gillespie algorithm is appropriate to simulate a stochastic
文摘This paper sets Chaihu Town, Zhongxiang City of Hubei Province as an example, analyzing the ecological and hydrological conditions of Chaihu Town, applying LID （low impact development） mode and putting forward the ecological stormwater regulation system planning strategy which adapts to the development of small towns. The main conclusions are as follows： （1） The ＂three-low＂ development mode is put forward, which means low impact, low cost and low carbon, using this construction mode to minimize the ecological impact, relying on natural green space and water to achieve the function of rainstorm regulation; （2） Through the analysis and calculation of the local amount of precipitation, this paper scientifically calculates the required area of storage water and green space, taking the roads as trunks, green spaces as stems, water as veins, and building the green infrastructure system; （3） The author has been repairing and integrating the original drainage ditches of the planning area, replacing traditional rain drainage pipes, establishing ＂two-loop＂ water network system which aims at the detention and purification of rainwater, maximizing ecological benefit, economic benefit and landscape benefit.
文摘After the new round of restructuring of Chinese telecom sector,it's pressing to formulate and implement asymmetric regulation policies so as to shape an effectively competitive market structure in a relatively short term.This paper reviewed the asymmetric regulation policies and practices carried out in foreign telecom market,and then according to the specific situations of Chinese telecom market,proposed the principles and corresponding policies for establishing an asymmetric regulation system fit for Chinese telecom market.
文摘Outlined the South African mine health and safety regulatory framework,in- cluding the roles of government,tripartite council,service agencies,mine enterprises, rescue stations and workers unions,analyzed the institutional structures of South African mine health and safety standardization,including the South African standard and specifi- cation systems and standard development processes,and characterized the South African mine health and safety standardization and regulation systems.Intended to provide some suggestions for the transformation and improvement of mine health and safety standardi- zation and regulation systems in China or in similar situations.
文摘Main Exhauster is one of the main equipment of sintering production. It needs to consume a lot of electricity. Therefore, the system＇ s reconstruction for energy-saving will effectively reduce electricity for the production. The paper takes an iron and steel enterprise that had successfully transformed the synchronous motors of main exhauster of sintering as an example, which describes the application of high-voltage variable frequency speed regulation system in main exhauster of Sintering, so as to provide a reference for other iron and steel enterprises.
文摘This paper presents the solution of regulating the wind rate automatically by means of fuzzy control technology and implementing it with PLC (programmable logical controller) under the circumstance of many influence factors, which exists in the axial flow fans wind rate regulation system during the process of mine ventilation, and has difficulty in modifying the mathematic model to obtain the satisfied result by normal control ways. According to this analysis, the intelligent and analytic treatment of fuzzy controller has been made and fuzzy control scheme involving self regulation divisor and intelligent integral has been deeply proposed. Test result shows that this system based on the scheme above is obviously prior to others in its responsibility such as high speed, overshoot, control precision and robustness. The system furnishes the great reliability of mine working safety and fans running efficiency.
文摘In order to scientifically deal with the problems of less water and more sediment in the Yellow River and the uncoordinated relationship between water and sediment,it is necessary to establish a perfect water and sediment regulation system.Through the calculation of the sediment transport capacity of the Yellow River and the application of the water and sediment regulation system,it is found that the sediment transport efficiency of the Yellow River will increase with the increase of water flow,and there will be an obvious inflection point near the flat discharge.The joint regulation of the backbone reservoir group can discharge the large discharge close to the minimum flat discharge of the downstream river,which improves the sediment transport capacity of the river and alleviates the problem of sediment deposition.In this paper,through the introduction of the Yellow River water and sediment regulation project system,regulation indicators and mechanisms,the author discusses in detail the Yellow River water and sediment regulation scheme and its operation effect,hoping to provide help promote the improvement of the Yellow River governance effect.
文摘Dear Editor,This letter focuses on the distributed cooperative regulation problem for a class of networked re-entrant manufacturing systems(RMSs).The networked system is structured with a three-tier architecture:the production line,the manufacturing layer and the workshop layer.The dynamics of re-entrant production lines are governed by hyperbolic partial differential equations(PDEs)based on the law of mass conservation.
基金supported by the National Natural Science Foundation of China(Grants No.W2412144,42271292)the 111 project,and the Fundamental Research Funds for the Central Universities of China.
文摘Amid ongoing global environmental change and the critical pursuit of sustainable development,human-environment systems are exhibiting increasingly complex dynamic evolutions and spatial relationships,underscoring an urgent need for innovative research frameworks.Integrated geography synthesizes physical geography,human geography,and geographic information science,providing key frameworks for understanding complex human-environment systems.This editorial proposes an emerging research framework for integrated geography—“Composite driving-System evolution-Coupling mechanism-Synergistic regulation(CSCS)”—based on key issues such as climate change,biodiversity loss,resource scarcity,and social-ecological interactions,which have been highlighted in both recent critical literature on human-environment systems and UN assessment reports.The framework starts with diverse composite driving forces,extends to the evolution of human-environment system structures,processes,and functions that these drivers induce,explores couplings within human-environment systems,and calls for regulation aimed at sustainable development in synergies.Major research frontiers include understanding the cascading“evolution-coupling”effects of shocks;measuring system resilience,thresholds,and safe and just operating space boundaries;clarifying linkage mechanisms across scales;and achieving synergistic outcomes for multi-objective sustainability.This framework will help promote the interdisciplinary integration and development of integrated geography,and provide geographical solutions for the global sustainable development agenda.
文摘This paper investigates the issue of load disturbances in DC motor speed regulation systems.In response to the limited disturbance rejection capability of traditional PID controllers,a PID controller with feedforward compensation is designed.The study first analyzes the dynamic impact mechanism of sudden load changes on motor speed,and then achieves precise control of the DC motor using PWM technology.Through comparative analysis of simulation and experimental results,the proposed feedforward-compens ated PID control demonstrates significant improvements in dynamic response speed,overshoot,and steady-state accuracy compared to traditional PID control.The findings indicate that the proposed control strategy effectively supp resses load disturbances,e nhances system stability and robustness,and offers valuable insights for practical engineering applications.
基金supported by the National Natural Science Foundation of China(Project No.52377082)the Scientific Research Program of Jilin Provincial Department of Education(Project No.JJKH20230123KJ).
文摘Large-scale new energy grid connection leads to the weakening of the system frequency regulation capability,and the system frequency stability is facing unprecedented challenges.In order to solve rapid frequency fluctuation caused by new energy units,this paper proposes a new energy power system frequency regulation strategy with multiple units including the doubly-fed pumped storage unit(DFPSU).Firstly,based on the model predictive control(MPC)theory,the state space equations are established by considering the operating characteristics of the units and the dynamic behavior of the system;secondly,the proportional-differential control link is introduced to minimize the frequency deviation to further optimize the frequency modulation(FM)output of the DFPSU and inhibit the rapid fluctuation of the frequency;lastly,it is verified on theMatlab/Simulink simulation platform,and the results show that the model predictive control with proportional-differential control link can further release the FM potential of the DFPSU,increase the depth of its FM,effectively reduce the frequency deviation of the system and its rate of change,realize the optimization of the active output of the DFPSU and that of other units,and improve the frequency response capability of the system.
基金supported by the National Natural Science Foundation of China(No.51979204 and No.52009096)the Hubei Provincial Natural Science Foundation of China(No.2022CFD165)the China Postdoctoral Science Foundation(No.2022T150498).
文摘To ensure system stability,the fixed-PID(F-PID)controller with small parameters is usually adopted in hydropower stations.This involves a slow setting speed and it is difficult to realize optimal control for full working conditions.To address the problem,this paper designs a variable-PID(V-PID)controller for a hydraulic turbine regulation system(HTRS)based on the improved grey wolf optimizer(INGWO)and back propagation neural networks(BPNN).These can achieve excellent regulation under full working conditions.First,the nonlinear HTRS model containing the nonlinear hydroturbine model is constructed and the stable domain is obtained using Hopf bifurcation theory to determine the available range of PID parameters.The optimal PID parameters in typical working conditions are then calculated by the INGWO,and the optimal PID parameters are generalized through training the V-PID neural networks which take the optimal PID parameters as sample data.The V-PID neural networks with different structures are compared to determine the optimal structure of the variable-PID controller model.The V-PID controller-based nonlinear HTRS model shows that the PID parameters can be automatically adjusted online according to the working condition changes,realizing optimal control of hydropower units in full working conditions.
基金supported by The National Key Research and Development Program of China(2023YFC3208605).
文摘Understanding the influencing factors and the evolving trends of the Water-Sediment Regulation System(WSRS)is vital for the protection and management of the Yellow River.Past studies on WSRS have been limited in focus and have not fully addressed the complete engineering control system of the basin.This study takes a holistic view,treating sediment management in the Yellow River as a dynamic and ever-evolving complex system.It merges concepts from system science,information theory,and dissipative structure with practical efforts in sediment engineering control.The key findings of this study are as follows:between 1990 and 2019,the average Yellow River Sediment Regulation Index(YSRI)was 55.99,with the lowest being 50.26 in 1990 and the highest being 61.48 in 2019;the result indicates that the WSRS activity decreased,yet it fluctuated,gradually approaching the critical threshold of a dissipative structure.
基金supported by the National Key Research and Development Program of China(2022YFF1102500)the Special Project of Central Guide to Local Science and Technology Development(Innovation platform construction for food green processing technology and intelligent equipment)(2022BGE247).
文摘The global shift towards sustainable food systems has sparked innovations in food sources and production systems,including cell-based meat,plant-based food products,precision fermentation,and 3D food printing.These advancements pose regulatory challenges and opportunities,with China emerging as a critical player in adopting and regulating new food technologies.This review explores the international landscape of new food sources and production systems(NFPS),focusing on China’s role and regulatory approaches compared to global practices.Through this comparative analysis,we aim to contribute to the ongoing dialogue on food safety regulation,offering insights and recommendations for policymakers,industry stakeholders,and researchers engaged in the global food system’s evolution.This comprehensive overview underscores the dynamic nature of regulatory frameworks governing NFPS,highlighting the international efforts to ensure food safety,consumer protection,and the sustainable evolution of the food industry.
基金supported by the National Natural Science Foundation of China (62073327,62273350)the Natural Science Foundation of Jiangsu Province (BK20221112)。
文摘This article studies the adaptive optimal output regulation problem for a class of interconnected singularly perturbed systems(SPSs) with unknown dynamics based on reinforcement learning(RL).Taking into account the slow and fast characteristics among system states,the interconnected SPS is decomposed into the slow time-scale dynamics and the fast timescale dynamics through singular perturbation theory.For the fast time-scale dynamics with interconnections,we devise a decentralized optimal control strategy by selecting appropriate weight matrices in the cost function.For the slow time-scale dynamics with unknown system parameters,an off-policy RL algorithm with convergence guarantee is given to learn the optimal control strategy in terms of measurement data.By combining the slow and fast controllers,we establish the composite decentralized adaptive optimal output regulator,and rigorously analyze the stability and optimality of the closed-loop system.The proposed decomposition design not only bypasses the numerical stiffness but also alleviates the high-dimensionality.The efficacy of the proposed methodology is validated by a load-frequency control application of a two-area power system.
基金the National Natural Science Foundation of China(NSFC)-Excellent Young Scientists Fund(Hong Kong and Macao)under Grant 62222318.
文摘This paper investigates the robust cooperative output regulation problem for a class of heterogeneousuncertain linear multi-agent systems with an unknown exosystem via event-triggered control (ETC). By utilizingthe internal model approach and the adaptive control technique, a distributed adaptive internal model isconstructed for each agent. Then, based on this internal model, a fully distributed ETC strategy composed ofa distributed event-triggered adaptive output feedback control law and a distributed dynamic event-triggeringmechanism is proposed, in which each agent updates its control input at its own triggering time instants. It isshown that under the proposed ETC strategy, the robust cooperative output regulation problem can be solvedwithout requiring either the global information associated with the communication topology or the bounds ofthe uncertain or unknown parameters in each agent and the exosystem. A numerical example is provided toillustrate the effectiveness of the proposed control strategy.
文摘To address the scheduling problem involving energy storage systems and uncertain energy,we propose a method based on multi-stage robust optimization.This approach aims to regulate the energy storage system by using a multi-stage robust optimal control method,which helps overcome the limitations of traditional methods in terms of time scale.The goal is to effectively utilize the energy storage power station system to address issues caused by unpredictable variations in environmental energy and fluctuating load throughout the day.To achieve this,a mathematical model is constructed to represent uncertain energy sources such as photovoltaic and wind power.The generalized Benders Decomposition method is then employed to solve the multi-stage objective optimization problem.By decomposing the problem into a series of sub-objectives,the system scale is effectively reduced,and the algorithm’s convergence ability is improved.Compared with other algorithms,the multi-stage robust optimization model has better economy and convergence ability and can be used to guide the power dispatching of uncertain energy and energy storage systems.
基金supported by the Surface Project of Local De-velopment in Science and Technology Guided by Central Govern-ment(No.2021ZYD0041)the National Natural Science Founda-tion of China(Nos.52377026 and 52301192)+3 种基金the Natural Science Foundation of Shandong Province(No.ZR2019YQ24)the Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202103057)the Special Financial of Shandong Province(Struc-tural Design of High-efficiency Electromagnetic Wave-absorbing Composite Materials and Construction of Shandong Provincial Tal-ent Teams)the“Sanqin Scholars”Innovation Teams Project of Shaanxi Province(Clean Energy Materials and High-Performance Devices Innovation Team of Shaanxi Dongling Smelting Co.,Ltd.).
文摘With the increasing complexity of the current electromagnetic environment,excessive microwave radi-ation not only does harm to human health but also forms various electromagnetic interference to so-phisticated electronic instruments.Therefore,the design and preparation of electromagnetic absorbing composites represent an efficient approach to mitigate the current hazards of electromagnetic radiation.However,traditional electromagnetic absorbers are difficult to satisfy the demands of actual utilization in the face of new challenges,and emerging absorbents have garnered increasing attention due to their structure and performance-based advantages.In this review,several emerging composites of Mxene-based,biochar-based,chiral,and heat-resisting are discussed in detail,including their synthetic strategy,structural superiority and regulation method,and final optimization of electromagnetic absorption ca-pacity.These insights provide a comprehensive reference for the future development of new-generation electromagnetic-wave absorption composites.Moreover,the potential development directions of these emerging absorbers have been proposed as well.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(Grant Nos.LQ23C150004 and LR23C150001)National Natural Science Foundation of China(NSFC+1 种基金Grant No.32102318)NSFC Excellent Young Scientists Fund,and the Key Project for New Agricultural Cultivar Breeding in Zhejiang Province,China(Grant No.2021C02066-1).
文摘Chlorophyll degradation and carotenoid accumulation are essential processes of fruit maturation in many horticultural plants,and play a crucial role in fruit color and quality.The pathways of chlorophyll and carotenoid biosynthesis and degradation are well understood,and key regulatory genes controlling these pathways have been identified in citrus.This article reviewed the recent research on chlorophyll and carotenoid metabolism in citrus fruits,encompassing the metabolic pathways,transcriptional regulation,influencing factors,and the interplay between chlorophyll and carotenoid metabolism,aiming to provide insights into the molecular regulatory mechanisms governing the coloration of citrus fruits.
