Many difficult engineering problems cannot be solved by the conventional optimization techniques in practice. Direct searches that need no recourse to explicit derivatives are revived and become popular since the new ...Many difficult engineering problems cannot be solved by the conventional optimization techniques in practice. Direct searches that need no recourse to explicit derivatives are revived and become popular since the new century. In order to get a deep insight into this field, some notes on the direct searches for non-smooth optimization problems are made. The global convergence vs. local convergence and their influences on expected solutions for simulation-based stochastic optimization are pointed out. The sufficient and simple decrease criteria for step acceptance are analyzed, and why simple decrease is enough for globalization in direct searches is identified. The reason to introduce the positive spanning set and its usage in direct searches is explained. Other topics such as the generalization of direct searches to bound, linear and non-linear constraints are also briefly discussed.展开更多
为降低大学城综合能源系统(integrated energy system,IES)尖峰负荷对电网运行安全性、经济性的冲击,制定了基于综合需求响应的大学城IES尖峰负荷平抑策略。构建了以电、气为多源供应,以电、热为综合需求的系统模型,并分析了其需求响应...为降低大学城综合能源系统(integrated energy system,IES)尖峰负荷对电网运行安全性、经济性的冲击,制定了基于综合需求响应的大学城IES尖峰负荷平抑策略。构建了以电、气为多源供应,以电、热为综合需求的系统模型,并分析了其需求响应机制;采用价格型需求响应和替代型需求响应相结合的响应策略,对系统中的多类型电热负荷进行分类优化,平滑负荷曲线;引入基于碳配额的碳交易机制,以系统收益为主要优化目标进行计算。算例分析表明,所提出的基于综合需求响应的IES运行策略能够平抑IES的尖峰负荷,提高系统运行经济性。展开更多
An effective hybrid optimization method is proposed by integrating an adaptive Kriging(A-Kriging)into an improved partial swarm optimization algorithm(IPSO)to give a so-called A-Kriging-IPSO for maximizing the bucklin...An effective hybrid optimization method is proposed by integrating an adaptive Kriging(A-Kriging)into an improved partial swarm optimization algorithm(IPSO)to give a so-called A-Kriging-IPSO for maximizing the buckling load of laminated composite plates(LCPs)under uniaxial and biaxial compressions.In this method,a novel iterative adaptive Kriging model,which is structured using two training sample sets as active and adaptive points,is utilized to directly predict the buckling load of the LCPs and to improve the efficiency of the optimization process.The active points are selected from the initial data set while the adaptive points are generated using the radial random-based convex samples.The cell-based smoothed discrete shear gap method(CS-DSG3)is employed to analyze the buckling behavior of the LCPs to provide the response of adaptive and input data sets.The buckling load of the LCPs is maximized by utilizing the IPSO algorithm.To demonstrate the efficiency and accuracy of the proposed methodology,the LCPs with different layers(2,3,4,and 10 layers),boundary conditions,aspect ratios and load patterns(biaxial and uniaxial loads)are investigated.The results obtained by proposed method are in good agreement with the literature results,but with less computational burden.By applying adaptive radial Kriging model,the accurate optimal resultsebased predictions of the buckling load are obtained for the studied LCPs.展开更多
针对传统快速随机搜索树^(*)(rapidly-exploring random tree^(*),RRT^(*))算法收敛速率较慢,且不适用于动态场景等问题,提出一种基于目标点偏置和冗余节点删除的改进RRT*算法,用于解决移动机器人快速找到无碰撞最优路径的问题。此算法...针对传统快速随机搜索树^(*)(rapidly-exploring random tree^(*),RRT^(*))算法收敛速率较慢,且不适用于动态场景等问题,提出一种基于目标点偏置和冗余节点删除的改进RRT*算法,用于解决移动机器人快速找到无碰撞最优路径的问题。此算法在RRT^(*)算法基础上,首先对采样点进行优化处理,保证路径最优的同时减少搜寻时间;其次引入路径节点最大值概念,删除扩展树冗余节点以提高算法效率;最后结合动态窗口(dynamic window approaches,DWA)算法提高路径的安全性和平滑性,实现对动态障碍物的避障。通过3种不同地图下的仿真验证,改进算法能有效提升路径质量,且大幅降低运行时间。展开更多
基金supported by the Key Foundation of Southwest University for Nationalities(09NZD001).
文摘Many difficult engineering problems cannot be solved by the conventional optimization techniques in practice. Direct searches that need no recourse to explicit derivatives are revived and become popular since the new century. In order to get a deep insight into this field, some notes on the direct searches for non-smooth optimization problems are made. The global convergence vs. local convergence and their influences on expected solutions for simulation-based stochastic optimization are pointed out. The sufficient and simple decrease criteria for step acceptance are analyzed, and why simple decrease is enough for globalization in direct searches is identified. The reason to introduce the positive spanning set and its usage in direct searches is explained. Other topics such as the generalization of direct searches to bound, linear and non-linear constraints are also briefly discussed.
文摘为降低大学城综合能源系统(integrated energy system,IES)尖峰负荷对电网运行安全性、经济性的冲击,制定了基于综合需求响应的大学城IES尖峰负荷平抑策略。构建了以电、气为多源供应,以电、热为综合需求的系统模型,并分析了其需求响应机制;采用价格型需求响应和替代型需求响应相结合的响应策略,对系统中的多类型电热负荷进行分类优化,平滑负荷曲线;引入基于碳配额的碳交易机制,以系统收益为主要优化目标进行计算。算例分析表明,所提出的基于综合需求响应的IES运行策略能够平抑IES的尖峰负荷,提高系统运行经济性。
基金Vietnam National Foundation for Science and Technology Development(NAFOSTED)under Grant number 107.02-2019.330.
文摘An effective hybrid optimization method is proposed by integrating an adaptive Kriging(A-Kriging)into an improved partial swarm optimization algorithm(IPSO)to give a so-called A-Kriging-IPSO for maximizing the buckling load of laminated composite plates(LCPs)under uniaxial and biaxial compressions.In this method,a novel iterative adaptive Kriging model,which is structured using two training sample sets as active and adaptive points,is utilized to directly predict the buckling load of the LCPs and to improve the efficiency of the optimization process.The active points are selected from the initial data set while the adaptive points are generated using the radial random-based convex samples.The cell-based smoothed discrete shear gap method(CS-DSG3)is employed to analyze the buckling behavior of the LCPs to provide the response of adaptive and input data sets.The buckling load of the LCPs is maximized by utilizing the IPSO algorithm.To demonstrate the efficiency and accuracy of the proposed methodology,the LCPs with different layers(2,3,4,and 10 layers),boundary conditions,aspect ratios and load patterns(biaxial and uniaxial loads)are investigated.The results obtained by proposed method are in good agreement with the literature results,but with less computational burden.By applying adaptive radial Kriging model,the accurate optimal resultsebased predictions of the buckling load are obtained for the studied LCPs.
文摘针对传统快速随机搜索树^(*)(rapidly-exploring random tree^(*),RRT^(*))算法收敛速率较慢,且不适用于动态场景等问题,提出一种基于目标点偏置和冗余节点删除的改进RRT*算法,用于解决移动机器人快速找到无碰撞最优路径的问题。此算法在RRT^(*)算法基础上,首先对采样点进行优化处理,保证路径最优的同时减少搜寻时间;其次引入路径节点最大值概念,删除扩展树冗余节点以提高算法效率;最后结合动态窗口(dynamic window approaches,DWA)算法提高路径的安全性和平滑性,实现对动态障碍物的避障。通过3种不同地图下的仿真验证,改进算法能有效提升路径质量,且大幅降低运行时间。
