随着可再生能源并网发电量的不断增加,由电力电子设备引发的电力系统次同步振荡问题逐渐凸显,给电力系统的安全稳定运行带来了新的挑战。除此之外,当目标电力系统规模较大时,常用的基于线性化模型的分析方法面临着维数灾难。为了解决上...随着可再生能源并网发电量的不断增加,由电力电子设备引发的电力系统次同步振荡问题逐渐凸显,给电力系统的安全稳定运行带来了新的挑战。除此之外,当目标电力系统规模较大时,常用的基于线性化模型的分析方法面临着维数灾难。为了解决上述问题,根据强化学习原理,通过动作-评价(Actor-Critic)学习框架提出一种对风机换流器控制参数的优化策略。通过搜集永磁直驱风机(permanent magnetic synchronous generator,PMSG)运行状态数据,训练强化学习代理(Agent),以此评估风机运行状态及其稳定性,并寻找优化风机换流器参数的最优策略。该训练方法得到的代理能够基于时域采样数据对风机换流器参数进行优化,从而有效抑制由于换流器诱发的振荡现象,在没有建立线性化分析模型的情况下,能够有效优化并增强电力系统的稳定性。经实验验证,该优化策略在采样数据有噪声干扰的情况下仍然具有良好的优化性能。展开更多
It is an important way to realize rural revitalization and sustainable development to guide rural settlement transition(RST)in an appropriate way.This paper uses actor network theory(ANT)to construct a theoretical fra...It is an important way to realize rural revitalization and sustainable development to guide rural settlement transition(RST)in an appropriate way.This paper uses actor network theory(ANT)to construct a theoretical framework for the study of RST.Taking two typical villages with different transition paths in rural areas of North China Plain as examples,this paper reveals the mechanism of RST and makes a comparative analysis.The results show that:1)after identifying problems and obligatory passage point,key actors recruit heterogeneous actors into the actor network by entrusting them with common interests,and realize RST under the system operation.2)Rural settlements under different transition paths have similarities in the problems to be solved,collective actions and policy factors,but there are differences in the transition process,mechanism and effect.The actor network and mechanism of RST through the path of new rural community construction are more complex and the transition effect is more thorough.In contrast,the degree of RST of retention development path is limited if there is no resource and location advantage.3)Based on the applicable conditions of different paths,this paper designs a logical framework of‘Situation-Structure-Behavior-Result’to scientifically guide the identification of RST paths under the background of rural revitalization.展开更多
Wireless Sensor Network(WSN)is widely utilized in large-scale distributed unmanned detection scenarios due to its low cost and flexible installation.However,WSN data collection encounters challenges in scenarios lacki...Wireless Sensor Network(WSN)is widely utilized in large-scale distributed unmanned detection scenarios due to its low cost and flexible installation.However,WSN data collection encounters challenges in scenarios lacking communication infrastructure.Unmanned aerial vehicle(UAV)offers a novel solution for WSN data collection,leveraging their high mobility.In this paper,we present an efficient UAV-assisted data collection algorithm aimed at minimizing the overall power consumption of the WSN.Firstly,a two-layer UAV-assisted data collection model is introduced,including the ground and aerial layers.The ground layer senses the environmental data by the cluster members(CMs),and the CMs transmit the data to the cluster heads(CHs),which forward the collected data to the UAVs.The aerial network layer consists of multiple UAVs that collect,store,and forward data from the CHs to the data center for analysis.Secondly,an improved clustering algorithm based on K-Means++is proposed to optimize the number and locations of CHs.Moreover,an Actor-Critic based algorithm is introduced to optimize the UAV deployment and the association with CHs.Finally,simulation results verify the effectiveness of the proposed algorithms.展开更多
Actor-Critic是一种强化学习方法,通过与环境在线试错交互收集样本来学习策略,是求解序贯感知决策问题的有效手段.但是,这种在线交互的主动学习范式在一些复杂真实环境中收集样本时会带来成本和安全问题离线强化学习作为一种基于数据驱...Actor-Critic是一种强化学习方法,通过与环境在线试错交互收集样本来学习策略,是求解序贯感知决策问题的有效手段.但是,这种在线交互的主动学习范式在一些复杂真实环境中收集样本时会带来成本和安全问题离线强化学习作为一种基于数据驱动的强化学习范式,强调从静态样本数据集中学习策略,与环境无探索交互,为机器人、自动驾驶、健康护理等真实世界部署应用提供了可行的解决方案,是近年来的研究热点.目前,离线强化学习方法存在学习策略和行为策略之间的分布偏移挑战,针对这个挑战,通常采用策略约束或值函数正则化来限制访问数据集分布之外(Out-Of-Distribution,OOD)的动作,从而导致学习性能过于保守,阻碍了值函数网络的泛化和学习策略的性能提升.为此,本文利用不确定性估计和OOD采样来平衡值函数学习的泛化性和保守性,提出一种基于不确定性估计的离线确定型Actor-Critic方法(Offline Deterministic Actor-Critic based on UncertaintyEstimation,ODACUE).首先,针对确定型策略,给出一种Q值函数的不确定性估计算子定义,理论证明了该算子学到的Q值函数是最优Q值函数的一种悲观估计.然后,将不确定性估计算子应用于确定型Actor-Critic框架中,通过对不确定性估计算子进行凸组合构造Critic学习的目标函数.最后,D4RL基准数据集任务上的实验结果表明:相较于对比算法,ODACUE在11个不同质量等级数据集任务中的总体性能提升最低达9.56%,最高达64.92%.此外,参数分析和消融实验进一步验证了ODACUE的稳定性和泛化能力.展开更多
The relationship between literature and society has been a subject of continuous exploration since the inception of literature itself.On the one hand,from Plato’s theory of mimesis onward,literature has consistently ...The relationship between literature and society has been a subject of continuous exploration since the inception of literature itself.On the one hand,from Plato’s theory of mimesis onward,literature has consistently been viewed as a representation of social reality,positioning literature as subordinate to society.On the other hand,with the rise of structuralism and the New Criticism,certain schools of thought have focused exclusively on literature itself,deliberately overlooking the complex connections between literature and society.The growing tension between these two perspectives has increasingly placed contemporary literary studies in a polarized state,leading to a crisis in the legitimacy of literary scholarship.In response to this,Rita Felski’s exploration of the uses of literature embodies a new literary sociology that offers a way out of the current impasse in literary studies.展开更多
文摘随着可再生能源并网发电量的不断增加,由电力电子设备引发的电力系统次同步振荡问题逐渐凸显,给电力系统的安全稳定运行带来了新的挑战。除此之外,当目标电力系统规模较大时,常用的基于线性化模型的分析方法面临着维数灾难。为了解决上述问题,根据强化学习原理,通过动作-评价(Actor-Critic)学习框架提出一种对风机换流器控制参数的优化策略。通过搜集永磁直驱风机(permanent magnetic synchronous generator,PMSG)运行状态数据,训练强化学习代理(Agent),以此评估风机运行状态及其稳定性,并寻找优化风机换流器参数的最优策略。该训练方法得到的代理能够基于时域采样数据对风机换流器参数进行优化,从而有效抑制由于换流器诱发的振荡现象,在没有建立线性化分析模型的情况下,能够有效优化并增强电力系统的稳定性。经实验验证,该优化策略在采样数据有噪声干扰的情况下仍然具有良好的优化性能。
基金Under the auspices of the Taishan Scholars Project Special FundsNational Natural Science Fundation of China(No.42077434,42001199)Youth Innovation Technology Project of Higher School in Shandong Province(No.2019RWG016)。
文摘It is an important way to realize rural revitalization and sustainable development to guide rural settlement transition(RST)in an appropriate way.This paper uses actor network theory(ANT)to construct a theoretical framework for the study of RST.Taking two typical villages with different transition paths in rural areas of North China Plain as examples,this paper reveals the mechanism of RST and makes a comparative analysis.The results show that:1)after identifying problems and obligatory passage point,key actors recruit heterogeneous actors into the actor network by entrusting them with common interests,and realize RST under the system operation.2)Rural settlements under different transition paths have similarities in the problems to be solved,collective actions and policy factors,but there are differences in the transition process,mechanism and effect.The actor network and mechanism of RST through the path of new rural community construction are more complex and the transition effect is more thorough.In contrast,the degree of RST of retention development path is limited if there is no resource and location advantage.3)Based on the applicable conditions of different paths,this paper designs a logical framework of‘Situation-Structure-Behavior-Result’to scientifically guide the identification of RST paths under the background of rural revitalization.
基金supported by the National Natural Science Foundation of China(NSFC)(61831002,62001076)the General Program of Natural Science Foundation of Chongqing(No.CSTB2023NSCQ-MSX0726,No.cstc2020jcyjmsxmX0878).
文摘Wireless Sensor Network(WSN)is widely utilized in large-scale distributed unmanned detection scenarios due to its low cost and flexible installation.However,WSN data collection encounters challenges in scenarios lacking communication infrastructure.Unmanned aerial vehicle(UAV)offers a novel solution for WSN data collection,leveraging their high mobility.In this paper,we present an efficient UAV-assisted data collection algorithm aimed at minimizing the overall power consumption of the WSN.Firstly,a two-layer UAV-assisted data collection model is introduced,including the ground and aerial layers.The ground layer senses the environmental data by the cluster members(CMs),and the CMs transmit the data to the cluster heads(CHs),which forward the collected data to the UAVs.The aerial network layer consists of multiple UAVs that collect,store,and forward data from the CHs to the data center for analysis.Secondly,an improved clustering algorithm based on K-Means++is proposed to optimize the number and locations of CHs.Moreover,an Actor-Critic based algorithm is introduced to optimize the UAV deployment and the association with CHs.Finally,simulation results verify the effectiveness of the proposed algorithms.
文摘Actor-Critic是一种强化学习方法,通过与环境在线试错交互收集样本来学习策略,是求解序贯感知决策问题的有效手段.但是,这种在线交互的主动学习范式在一些复杂真实环境中收集样本时会带来成本和安全问题离线强化学习作为一种基于数据驱动的强化学习范式,强调从静态样本数据集中学习策略,与环境无探索交互,为机器人、自动驾驶、健康护理等真实世界部署应用提供了可行的解决方案,是近年来的研究热点.目前,离线强化学习方法存在学习策略和行为策略之间的分布偏移挑战,针对这个挑战,通常采用策略约束或值函数正则化来限制访问数据集分布之外(Out-Of-Distribution,OOD)的动作,从而导致学习性能过于保守,阻碍了值函数网络的泛化和学习策略的性能提升.为此,本文利用不确定性估计和OOD采样来平衡值函数学习的泛化性和保守性,提出一种基于不确定性估计的离线确定型Actor-Critic方法(Offline Deterministic Actor-Critic based on UncertaintyEstimation,ODACUE).首先,针对确定型策略,给出一种Q值函数的不确定性估计算子定义,理论证明了该算子学到的Q值函数是最优Q值函数的一种悲观估计.然后,将不确定性估计算子应用于确定型Actor-Critic框架中,通过对不确定性估计算子进行凸组合构造Critic学习的目标函数.最后,D4RL基准数据集任务上的实验结果表明:相较于对比算法,ODACUE在11个不同质量等级数据集任务中的总体性能提升最低达9.56%,最高达64.92%.此外,参数分析和消融实验进一步验证了ODACUE的稳定性和泛化能力.
文摘The relationship between literature and society has been a subject of continuous exploration since the inception of literature itself.On the one hand,from Plato’s theory of mimesis onward,literature has consistently been viewed as a representation of social reality,positioning literature as subordinate to society.On the other hand,with the rise of structuralism and the New Criticism,certain schools of thought have focused exclusively on literature itself,deliberately overlooking the complex connections between literature and society.The growing tension between these two perspectives has increasingly placed contemporary literary studies in a polarized state,leading to a crisis in the legitimacy of literary scholarship.In response to this,Rita Felski’s exploration of the uses of literature embodies a new literary sociology that offers a way out of the current impasse in literary studies.
文摘提出一种基于模糊RBF网络的自适应模糊A ctor-C ritic学习.采用一个模糊RBF神经网络同时逼近A ctor的动作函数和C ritic的值函数,解决状态空间泛化中易出现的“维数灾”问题.模糊RBF网络能够根据环境状态和被控对象特性的变化进行网络结构和参数的自适应学习,使得网络结构更加紧凑,整个模糊A ctor-C ritic学习具有泛化性能好、控制结构简单和学习效率高的特点.M oun ta in C ar的仿真结果验证了所提方法的有效性.
