单主用户信号的出现主要引起多天线接收信号取样协方差矩阵中极值特征值的变化,而多主用户信号的出现则会同时扰动取样协方差矩阵极值特征值和其他特征值,此时,经典的极值特征值检测算法则会表现出次佳的检测性能。针对这一问题,本研究...单主用户信号的出现主要引起多天线接收信号取样协方差矩阵中极值特征值的变化,而多主用户信号的出现则会同时扰动取样协方差矩阵极值特征值和其他特征值,此时,经典的极值特征值检测算法则会表现出次佳的检测性能。针对这一问题,本研究设计了一种基于极值特征值差与特征值几何平均(difference of extreme eigenvalues and geometric average of eigenvalues,DEEGAE)的多主用户信号检测判决规则;提出了一种基于Wishart矩阵特征值统计分布理论的感知判决门限的闭式求解方法。该算法在频谱感知过程中直接利用认知用户的多天线接收数据构造判决规则并实施感知判决,具有全盲检测的优点;通过融合2种极限特征值门限分析结果,提高了非渐近感知条件下感知结果的准确性。Monte-Carlo仿真试验表明,新算法具有比经典的最大最小特征值之比算法和协方差绝对值检测算法更优的多主用户信号检测性能,同时能获得比传统基于最大最小特征值之差及其改进算法更为可靠的检测结果;与此同时,新算法的检测性能随着样本数目以及天线数目的增大而显著提升。展开更多
To obtain the optimal process parameters of stamping forming, finite element analysis and optimization technique were integrated via transforming multi-objective issue into a single-objective issue. A Pareto-based gen...To obtain the optimal process parameters of stamping forming, finite element analysis and optimization technique were integrated via transforming multi-objective issue into a single-objective issue. A Pareto-based genetic algorithm was applied to optimizing the head stamping forming process. In the proposed optimal model, fracture, wrinkle and thickness varying are a function of several factors, such as fillet radius, draw-bead position, blank size and blank-holding force. Hence, it is necessary to investigate the relationship between the objective functions and the variables in order to make objective functions varying minimized simultaneously. Firstly, the central composite experimental(CCD) with four factors and five levels was applied, and the experimental data based on the central composite experimental were acquired. Then, the response surface model(RSM) was set up and the results of the analysis of variance(ANOVA) show that it is reliable to predict the fracture, wrinkle and thickness varying functions by the response surface model. Finally, a Pareto-based genetic algorithm was used to find out a set of Pareto front, which makes fracture, wrinkle and thickness varying minimized integrally. A head stamping case indicates that the present method has higher precision and practicability compared with the "trial and error" procedure.展开更多
在双碳目标的背景下,虚拟电厂、微电网等形式的产消者大规模涌现。多产消者之间的能量共享能够提升整体的经济效益与新能源消纳水平。在计及各产消者数据隐私的基础上,文中提出弱中心化模式下的多产消者能量共享协同运行机制。首先,构...在双碳目标的背景下,虚拟电厂、微电网等形式的产消者大规模涌现。多产消者之间的能量共享能够提升整体的经济效益与新能源消纳水平。在计及各产消者数据隐私的基础上,文中提出弱中心化模式下的多产消者能量共享协同运行机制。首先,构建含多种分布式资源的产消者内部调度模型,并考虑负荷需求以及新能源出力的波动性与随机性,基于条件风险价值(conditional value at risk,CVaR)量化不确定性带来的风险。然后,提出多产消者弱中心化电价迭代机制,利用供需关系引导电价更新。同时考虑到产消者隐私保护,基于Paillier同态加密算法和秘密共享原理设计电量数据聚合方法。该方法能够在各方主体隐私得到保护的前提下获取系统的供需信息。最后,通过算例验证了文中所提机制的有效性与合理性,且经过能量共享后多产消者整体成本降低12.6%。展开更多
文摘单主用户信号的出现主要引起多天线接收信号取样协方差矩阵中极值特征值的变化,而多主用户信号的出现则会同时扰动取样协方差矩阵极值特征值和其他特征值,此时,经典的极值特征值检测算法则会表现出次佳的检测性能。针对这一问题,本研究设计了一种基于极值特征值差与特征值几何平均(difference of extreme eigenvalues and geometric average of eigenvalues,DEEGAE)的多主用户信号检测判决规则;提出了一种基于Wishart矩阵特征值统计分布理论的感知判决门限的闭式求解方法。该算法在频谱感知过程中直接利用认知用户的多天线接收数据构造判决规则并实施感知判决,具有全盲检测的优点;通过融合2种极限特征值门限分析结果,提高了非渐近感知条件下感知结果的准确性。Monte-Carlo仿真试验表明,新算法具有比经典的最大最小特征值之比算法和协方差绝对值检测算法更优的多主用户信号检测性能,同时能获得比传统基于最大最小特征值之差及其改进算法更为可靠的检测结果;与此同时,新算法的检测性能随着样本数目以及天线数目的增大而显著提升。
基金Project(2012ZX04010-081) supported by the National Science and Technology Major Project of the Ministry of Science and Technology of China
文摘To obtain the optimal process parameters of stamping forming, finite element analysis and optimization technique were integrated via transforming multi-objective issue into a single-objective issue. A Pareto-based genetic algorithm was applied to optimizing the head stamping forming process. In the proposed optimal model, fracture, wrinkle and thickness varying are a function of several factors, such as fillet radius, draw-bead position, blank size and blank-holding force. Hence, it is necessary to investigate the relationship between the objective functions and the variables in order to make objective functions varying minimized simultaneously. Firstly, the central composite experimental(CCD) with four factors and five levels was applied, and the experimental data based on the central composite experimental were acquired. Then, the response surface model(RSM) was set up and the results of the analysis of variance(ANOVA) show that it is reliable to predict the fracture, wrinkle and thickness varying functions by the response surface model. Finally, a Pareto-based genetic algorithm was used to find out a set of Pareto front, which makes fracture, wrinkle and thickness varying minimized integrally. A head stamping case indicates that the present method has higher precision and practicability compared with the "trial and error" procedure.
文摘在双碳目标的背景下,虚拟电厂、微电网等形式的产消者大规模涌现。多产消者之间的能量共享能够提升整体的经济效益与新能源消纳水平。在计及各产消者数据隐私的基础上,文中提出弱中心化模式下的多产消者能量共享协同运行机制。首先,构建含多种分布式资源的产消者内部调度模型,并考虑负荷需求以及新能源出力的波动性与随机性,基于条件风险价值(conditional value at risk,CVaR)量化不确定性带来的风险。然后,提出多产消者弱中心化电价迭代机制,利用供需关系引导电价更新。同时考虑到产消者隐私保护,基于Paillier同态加密算法和秘密共享原理设计电量数据聚合方法。该方法能够在各方主体隐私得到保护的前提下获取系统的供需信息。最后,通过算例验证了文中所提机制的有效性与合理性,且经过能量共享后多产消者整体成本降低12.6%。
