针对电力负荷数据中存在的不平衡小类样本导致负荷预测精度不高问题,提出一种基于K-means-SyMProD-PCA数据预处理及NPMA-LSSVM模型的电力负荷预测方法。通过改进的K均值(K-means)方法根据电力负荷特性对其进行预分类,并构建分类标签作...针对电力负荷数据中存在的不平衡小类样本导致负荷预测精度不高问题,提出一种基于K-means-SyMProD-PCA数据预处理及NPMA-LSSVM模型的电力负荷预测方法。通过改进的K均值(K-means)方法根据电力负荷特性对其进行预分类,并构建分类标签作为输入特征;针对电力负荷分类后的样本类别不平衡问题,采用基于概率分布合成小类样本(synthetic minority based on probabilistic distribution,SyMProD)方法扩充小类样本数据以平衡样本类别;为了消除具有重复信息的特征,基于主成分分析(principal component analysis,PCA)方法提取电力负荷主要特征;最后建立最小二乘支持向量机(least square support vector machine,LSSVM)电力负荷预测模型,采用非线性惯性因子和多项式变异的蜉蝣算法对模型参数进行优化,以提高负荷预测精度。分别采用第9届电工杯建模大赛数据和扬中市2015年1443家企业的用电量数据作为验证数据,结果表明,结合K-means-SyMProD-PCA负荷数据预处理,NPMA-LSSVM预测模型有效降低了电力负荷预测误差,能够较好地解决不平衡小类样本情况下的中短期电力负荷预测问题,具有一定的适用性。展开更多
Rail corrugation, as a prevalent type of rail damage in heavy railways, induces diseases in the track structure. In order to ensure the safe operation of trains, an improved whale optimization algorithm is proposed to...Rail corrugation, as a prevalent type of rail damage in heavy railways, induces diseases in the track structure. In order to ensure the safe operation of trains, an improved whale optimization algorithm is proposed to optimize the rail corrugation evolution trend prediction model of the least squares support vector machine (IPCA-ELWOA-LSSVM). The elite reverse learning combined with the Lévy flight strategy is introduced to improve the whale optimization algorithm. The improved WOA (ELWOA) algorithm is used to continuously optimize the kernel parameter σ and the normalization parameter γ in the LSSVM model. Finally, the improved prediction model is validated using data from a domestic heavy-duty railway experimental line database and compared with the prediction model before optimization and the other commonly used models. The experimental results show that the ELWOA-LSSVM prediction model has the highest accuracy, which proves that the proposed method has high accuracy in predicting the rail corrugation evolution trend.展开更多
针对基于最小二乘支持向量机(least squares support vector machine,LSSVM)高程拟合模型存在参数选取随机的局限性,本文将果蝇优化算法(fruit fly optimization algorithm,FOA)引入到灰色最小二乘支持向量机(grey least square support...针对基于最小二乘支持向量机(least squares support vector machine,LSSVM)高程拟合模型存在参数选取随机的局限性,本文将果蝇优化算法(fruit fly optimization algorithm,FOA)引入到灰色最小二乘支持向量机(grey least square support vector machine,GLSSVM)高程拟合模型中,建立了基于FOA的GLSSVM拟合模型.为了验证提出模型的有效性,结合工程实例,并与GLSSVM、LSSVM进行对比分析,结果表明提出模型具有收敛快、精度高的特点,为GNSS高程拟合提供了新的思路.展开更多
文摘针对电力负荷数据中存在的不平衡小类样本导致负荷预测精度不高问题,提出一种基于K-means-SyMProD-PCA数据预处理及NPMA-LSSVM模型的电力负荷预测方法。通过改进的K均值(K-means)方法根据电力负荷特性对其进行预分类,并构建分类标签作为输入特征;针对电力负荷分类后的样本类别不平衡问题,采用基于概率分布合成小类样本(synthetic minority based on probabilistic distribution,SyMProD)方法扩充小类样本数据以平衡样本类别;为了消除具有重复信息的特征,基于主成分分析(principal component analysis,PCA)方法提取电力负荷主要特征;最后建立最小二乘支持向量机(least square support vector machine,LSSVM)电力负荷预测模型,采用非线性惯性因子和多项式变异的蜉蝣算法对模型参数进行优化,以提高负荷预测精度。分别采用第9届电工杯建模大赛数据和扬中市2015年1443家企业的用电量数据作为验证数据,结果表明,结合K-means-SyMProD-PCA负荷数据预处理,NPMA-LSSVM预测模型有效降低了电力负荷预测误差,能够较好地解决不平衡小类样本情况下的中短期电力负荷预测问题,具有一定的适用性。
文摘Rail corrugation, as a prevalent type of rail damage in heavy railways, induces diseases in the track structure. In order to ensure the safe operation of trains, an improved whale optimization algorithm is proposed to optimize the rail corrugation evolution trend prediction model of the least squares support vector machine (IPCA-ELWOA-LSSVM). The elite reverse learning combined with the Lévy flight strategy is introduced to improve the whale optimization algorithm. The improved WOA (ELWOA) algorithm is used to continuously optimize the kernel parameter σ and the normalization parameter γ in the LSSVM model. Finally, the improved prediction model is validated using data from a domestic heavy-duty railway experimental line database and compared with the prediction model before optimization and the other commonly used models. The experimental results show that the ELWOA-LSSVM prediction model has the highest accuracy, which proves that the proposed method has high accuracy in predicting the rail corrugation evolution trend.
文摘针对基于最小二乘支持向量机(least squares support vector machine,LSSVM)高程拟合模型存在参数选取随机的局限性,本文将果蝇优化算法(fruit fly optimization algorithm,FOA)引入到灰色最小二乘支持向量机(grey least square support vector machine,GLSSVM)高程拟合模型中,建立了基于FOA的GLSSVM拟合模型.为了验证提出模型的有效性,结合工程实例,并与GLSSVM、LSSVM进行对比分析,结果表明提出模型具有收敛快、精度高的特点,为GNSS高程拟合提供了新的思路.
