The Sluice Gate with Freight Carts is the earliest extant scroll in China that depicted a water mill.It was drawn during the early or middle Northern Song dynasty and was possibly a true portrayal of the West Water Mi...The Sluice Gate with Freight Carts is the earliest extant scroll in China that depicted a water mill.It was drawn during the early or middle Northern Song dynasty and was possibly a true portrayal of the West Water Mill Office.The copresence of a banquet scene of the Northern Song dynasty’s scholar-officials and a water mill both suggests a realistic reproduction of a specific scene and indicates the significance of the water mill as a cultural space.The Northern Song dynasty’s government-operated water mills were especially noticeable in the Capital Circuit京畿路,whose center was Dongjing东京.The basic development path of government-operated water mills in the inner and outer city of Dongjing was first from grain processing,which supplied the needs of the imperial palace,to tea processing,in which the governmental commercial capital also participated.Regarding city space and the use of water sources,the development spread from the north of the city to the south.Other prefectures outside Dongjing also had government-operated water mills—some brought income that could be used as official fiscal expenditure,including military expenditure,and were used to satisfy the need of local people’s livelihood,while some were used to serve the monopoly policy of tea and demonstrate the benevolent governance of local officials.In the Northern Song dynasty,the water mill was no longer merely a production site;rather,it was also a cultural space that integrated a natural background and artificial ingenuity.Closely related to the hosting of emperors and the garden making,sightseeing,feasting,and drinking of scholar-officials,along with the festival activities of locals,the water mill in the Northern Song dynasty was of great cultural significance.展开更多
针对滚动轴承故障诊断过程中样本处理、故障识别等技术问题,提出一种基于Morlet小波和分类回归树(Classification and Regression Tree,CART)的滚动轴承故障诊断方法。首先,利用Morlet小波分析方法和移动窗方法对轴承振动信号进行样本...针对滚动轴承故障诊断过程中样本处理、故障识别等技术问题,提出一种基于Morlet小波和分类回归树(Classification and Regression Tree,CART)的滚动轴承故障诊断方法。首先,利用Morlet小波分析方法和移动窗方法对轴承振动信号进行样本处理。其次,对提取的短样本进行变分模态分解与特征提取,完成训练集和测试集的构建。然后,使用训练集训练CART决策树分类模型,同时引入随机搜索和K折交叉验证用于模型关键参数优化,以获取理想的轴承故障分类模型。测试集验证结果表明,该方法不但能实现多种轴承故障的有效诊断、在含噪测试集中表现良好,而且单个样本的数据长度和采样时长的缩短效果明显。展开更多
分布式光伏受天气影响较大,测算110kV供电区域的分布式光伏承载能力,对区域供电来说意义重大。基于此,提出基于分类与回归树(calssification and regression tree,CART)的110kV供电区域分布式光伏承载能力测算模型。该模型以分布式电源...分布式光伏受天气影响较大,测算110kV供电区域的分布式光伏承载能力,对区域供电来说意义重大。基于此,提出基于分类与回归树(calssification and regression tree,CART)的110kV供电区域分布式光伏承载能力测算模型。该模型以分布式电源输出功率、区域分布式电源发电量占比、局部分布式电源线损增量等数据为基础,利用CART决策树建立110kV供电区域分布式光伏承载能力测算模型,并使用改进鲸鱼优化算法求解测算结果。经实验测试发现,该模型对分布式光伏承载能力的测算精准度较高,可有效测算不同实验区域在不同季节时的分布式光伏承载能力,具有较高的应用价值。展开更多
文摘The Sluice Gate with Freight Carts is the earliest extant scroll in China that depicted a water mill.It was drawn during the early or middle Northern Song dynasty and was possibly a true portrayal of the West Water Mill Office.The copresence of a banquet scene of the Northern Song dynasty’s scholar-officials and a water mill both suggests a realistic reproduction of a specific scene and indicates the significance of the water mill as a cultural space.The Northern Song dynasty’s government-operated water mills were especially noticeable in the Capital Circuit京畿路,whose center was Dongjing东京.The basic development path of government-operated water mills in the inner and outer city of Dongjing was first from grain processing,which supplied the needs of the imperial palace,to tea processing,in which the governmental commercial capital also participated.Regarding city space and the use of water sources,the development spread from the north of the city to the south.Other prefectures outside Dongjing also had government-operated water mills—some brought income that could be used as official fiscal expenditure,including military expenditure,and were used to satisfy the need of local people’s livelihood,while some were used to serve the monopoly policy of tea and demonstrate the benevolent governance of local officials.In the Northern Song dynasty,the water mill was no longer merely a production site;rather,it was also a cultural space that integrated a natural background and artificial ingenuity.Closely related to the hosting of emperors and the garden making,sightseeing,feasting,and drinking of scholar-officials,along with the festival activities of locals,the water mill in the Northern Song dynasty was of great cultural significance.
文摘针对滚动轴承故障诊断过程中样本处理、故障识别等技术问题,提出一种基于Morlet小波和分类回归树(Classification and Regression Tree,CART)的滚动轴承故障诊断方法。首先,利用Morlet小波分析方法和移动窗方法对轴承振动信号进行样本处理。其次,对提取的短样本进行变分模态分解与特征提取,完成训练集和测试集的构建。然后,使用训练集训练CART决策树分类模型,同时引入随机搜索和K折交叉验证用于模型关键参数优化,以获取理想的轴承故障分类模型。测试集验证结果表明,该方法不但能实现多种轴承故障的有效诊断、在含噪测试集中表现良好,而且单个样本的数据长度和采样时长的缩短效果明显。
文摘分布式光伏受天气影响较大,测算110kV供电区域的分布式光伏承载能力,对区域供电来说意义重大。基于此,提出基于分类与回归树(calssification and regression tree,CART)的110kV供电区域分布式光伏承载能力测算模型。该模型以分布式电源输出功率、区域分布式电源发电量占比、局部分布式电源线损增量等数据为基础,利用CART决策树建立110kV供电区域分布式光伏承载能力测算模型,并使用改进鲸鱼优化算法求解测算结果。经实验测试发现,该模型对分布式光伏承载能力的测算精准度较高,可有效测算不同实验区域在不同季节时的分布式光伏承载能力,具有较高的应用价值。
