This paper proposes one method of feature selection by using Bayes＇ theorem. The purpose of the proposed method is to reduce the computational complexity and increase the classification accuracy of the selected featu...This paper proposes one method of feature selection by using Bayes＇ theorem. The purpose of the proposed method is to reduce the computational complexity and increase the classification accuracy of the selected feature subsets. The dependence between two attributes （binary） is determined based on the probabilities of their joint values that contribute to positive and negative classification decisions. If opposing sets of attribute values do not lead to opposing classification decisions （zero probability）, then the two attributes are considered independent of each other, otherwise dependent, and one of them can be removed and thus the number of attributes is reduced. The process must be repeated on all combinations of attributes. The paper also evaluates the approach by comparing it with existing feature selection algorithms over 8 datasets from University of California, Irvine （UCI） machine learning databases. The proposed method shows better results in terms of number of selected features, classification accuracy, and running time than most existing algorithms.展开更多
将概率论运用于刑事审判中的事实认定的尝试已有百余年的历史,1968年美国加州最高法院在人民诉柯林斯案(Peoples v. Collins)中基于四个方面的理由对此做出否定回答。20世纪90年代DNA技术的发展给概率证据打开了通往法庭大门的钥匙。但...将概率论运用于刑事审判中的事实认定的尝试已有百余年的历史,1968年美国加州最高法院在人民诉柯林斯案(Peoples v. Collins)中基于四个方面的理由对此做出否定回答。20世纪90年代DNA技术的发展给概率证据打开了通往法庭大门的钥匙。但除此之外,无论是先验概率、经验概率,还是贝叶斯定理,概率论在事实认定中发挥更大作用的努力遇到了各种各样的问题。因此,以概率推理为基础逻辑,将“审判智能决策”推广到事实认定领域的尝试注定不会成功。展开更多
随着“双碳”目标的推进,大规模新能源并网使电网背景谐波呈现强波动性,导致现有系统谐波阻抗估计方法精确度降低,进而影响谐波主导扰动源定位与后续针对性治理。因此,针对新能源场站并网场景,研究系统谐波阻抗的精确估计对解决电网谐...随着“双碳”目标的推进,大规模新能源并网使电网背景谐波呈现强波动性,导致现有系统谐波阻抗估计方法精确度降低,进而影响谐波主导扰动源定位与后续针对性治理。因此,针对新能源场站并网场景,研究系统谐波阻抗的精确估计对解决电网谐波污染问题有重要意义。从数据驱动的角度出发,在新能源场站并网点建立了谐波阻抗评估模型。首先,针对背景谐波波动干扰的非理想条件,引入伊潘涅切科夫核函数拟合背景谐波电压的概率密度函数;其次,对于系统侧谐波阻抗值的估计,提出了基于改进贝叶斯的谐波阻抗估计方法,应用贝叶斯方法评估谐波阻抗时,基于熵最大原则和自分析法确定先验均匀分布区间范围;然后,针对样本容量过大导致估计过程耗时较长的问题,提出了基于最大最小优化拉丁超立方体采样法对公共连接点(point of common coupling,PCC)的数据样本进行筛选;最后,通过MATLAB/Simulink仿真分析的计算,验证了所提系统侧阻抗估计方法在背景谐波波动干扰时具有较高精度。展开更多
文摘This paper proposes one method of feature selection by using Bayes＇ theorem. The purpose of the proposed method is to reduce the computational complexity and increase the classification accuracy of the selected feature subsets. The dependence between two attributes （binary） is determined based on the probabilities of their joint values that contribute to positive and negative classification decisions. If opposing sets of attribute values do not lead to opposing classification decisions （zero probability）, then the two attributes are considered independent of each other, otherwise dependent, and one of them can be removed and thus the number of attributes is reduced. The process must be repeated on all combinations of attributes. The paper also evaluates the approach by comparing it with existing feature selection algorithms over 8 datasets from University of California, Irvine （UCI） machine learning databases. The proposed method shows better results in terms of number of selected features, classification accuracy, and running time than most existing algorithms.
文摘将概率论运用于刑事审判中的事实认定的尝试已有百余年的历史,1968年美国加州最高法院在人民诉柯林斯案(Peoples v. Collins)中基于四个方面的理由对此做出否定回答。20世纪90年代DNA技术的发展给概率证据打开了通往法庭大门的钥匙。但除此之外,无论是先验概率、经验概率,还是贝叶斯定理,概率论在事实认定中发挥更大作用的努力遇到了各种各样的问题。因此,以概率推理为基础逻辑,将“审判智能决策”推广到事实认定领域的尝试注定不会成功。
文摘随着“双碳”目标的推进,大规模新能源并网使电网背景谐波呈现强波动性,导致现有系统谐波阻抗估计方法精确度降低,进而影响谐波主导扰动源定位与后续针对性治理。因此,针对新能源场站并网场景,研究系统谐波阻抗的精确估计对解决电网谐波污染问题有重要意义。从数据驱动的角度出发,在新能源场站并网点建立了谐波阻抗评估模型。首先,针对背景谐波波动干扰的非理想条件,引入伊潘涅切科夫核函数拟合背景谐波电压的概率密度函数;其次,对于系统侧谐波阻抗值的估计,提出了基于改进贝叶斯的谐波阻抗估计方法,应用贝叶斯方法评估谐波阻抗时,基于熵最大原则和自分析法确定先验均匀分布区间范围;然后,针对样本容量过大导致估计过程耗时较长的问题,提出了基于最大最小优化拉丁超立方体采样法对公共连接点(point of common coupling,PCC)的数据样本进行筛选;最后,通过MATLAB/Simulink仿真分析的计算,验证了所提系统侧阻抗估计方法在背景谐波波动干扰时具有较高精度。
