The Kou watershed, situated in the Southwestern part of Burkina Faso, has succumbed since a couple of decades in a typical theater play of anarchistic water management. With its 1800 km2, this small watershed holds th...The Kou watershed, situated in the Southwestern part of Burkina Faso, has succumbed since a couple of decades in a typical theater play of anarchistic water management. With its 1800 km2, this small watershed holds the second largest city of Burkina Faso (Bobo-Dioulasso), a former State ran irrigated rice scheme and several informal agricultural zones. Despite the abundance on water resources, most water users find themselves regularly facing to water shortages due to an increase in population and low irrigation efficiencies. Local stakeholders are hence in need of easy-to-use and low-cost decision support tools for the monitoring and exploitation of the water resources at different spatial and user levels. A top-to-bottom string of adapted water management tools has been successfully installed to tackle the problems: from watershed (top) to field level (bottom), passing by the 1200 ha irrigation scheme. Land use maps have been derived from time-series of free satellite images. Combined with data from a network of hydrologic gauging stations, regional water use maps were established. SIMIS was put in place for the public-private management of the regions irrigated rice scheme. Day to day water use on irrigated plots was followed by soil humidity and crop canopy measurements. A simple field-cropwater balance model Aqua Crop was used by extension workers to draft optimal irrigation charts. Each tool was applied independently, requiring only limited data;but their combined results contributed to an improved integrated water management.展开更多
目的应用多水平模型分析职业人群的社会功能状态,为今后该类研究提供方法学参考。方法采用综合性工作能力指数（comprehensive work ability index,CWAI）量表,对来自不同单位的1686例研究对象进行社会功能状态测量。利用MLwiN2.0软件...目的应用多水平模型分析职业人群的社会功能状态,为今后该类研究提供方法学参考。方法采用综合性工作能力指数（comprehensive work ability index,CWAI）量表,对来自不同单位的1686例研究对象进行社会功能状态测量。利用MLwiN2.0软件拟合三水平方差成分模型,评价职工社会适应、社会支持和人际关系等社会功能状态。结果单位效应对职工社会功能状态有影响（χ~2=4.027,P=0.0448）;劳动类型联合检验结果有统计学意义（χ~2=12.721,P=0.0017）,体力劳动者比脑体混合劳动者的社会功能状态差（χ~2=10.223,P=0.0014）;脑力劳动者与脑体混合劳动者的社会功能状态无统计学差异（χ~2=0.015,P=0.9025）;经济收入越高的职工社会功能状态越好（χ~2=8.268,P=0.0040）;患有工作有关的肌肉骨骼疾患（work-related musculoskeletal disorders,WRMDs）的职工比未患该病的职工社会功能状态差（χ~2=22.218,P=0.0001）。结论单位、劳动类型、经济收入、工作有关的肌肉骨骼疾患是职工社会功能状态的重要影响因素。展开更多
雷电及操作过电压的识别,对改进和提高电力系统绝缘配合水平具有重要意义。提出了一种基于时频矩阵奇异值分解(singular value decomposition,SVD)和多级支持向量机(support vector machine,SVM)的雷电及操作过电压识别方法,通过对过电...雷电及操作过电压的识别,对改进和提高电力系统绝缘配合水平具有重要意义。提出了一种基于时频矩阵奇异值分解(singular value decomposition,SVD)和多级支持向量机(support vector machine,SVM)的雷电及操作过电压识别方法,通过对过电压信号的小波分解,构建多尺度时频矩阵,利用SVD对该矩阵进行奇异值分解,将信号分解到不同的时频特征子空间,然后获取过电压信号的奇异谱,并计算奇异谱的特征量,将这些特征量作为多级SVM的输入,实现雷电及操作过电压的辨识。对变电站实测5种过电压信号的计算表明:提取的特征量维数低,对过电压信号的电磁干扰具有相对稳定性;采用的识别方法训练次数少,识别率高,能够实现雷电及操作过电压的准确分类。展开更多
针对模块化多电平换流器(modular multi-level converter,MMC)子模块开路故障特点,提出一种基于无监督学习-最小二乘互信息谱聚类和整体最小二乘支持向量机(total least square support vector machines,TLS-SVM)的故障诊断方法,前者用...针对模块化多电平换流器(modular multi-level converter,MMC)子模块开路故障特点,提出一种基于无监督学习-最小二乘互信息谱聚类和整体最小二乘支持向量机(total least square support vector machines,TLS-SVM)的故障诊断方法,前者用于故障特征信息提取,后者用于故障分类识别。在MATLAB/Simulink环境下,搭建可进行故障设置的201电平MMC仿真系统。对采集到的换流器正常和故障运行时的三相电流信号通过滤波去噪处理后,进行Hilbert包络分解得到包络均值,使用最小二乘互信息谱聚类对包络均值进行二分类并获得标签集,然后将标签集和数据集作为基于整体最小二乘支持向量机的训练集并获得分类模型,最后对MMC故障进行分类和识别。仿真实验结果表明,该方法能有效识别高电平MMC的开路故障,并能实现智能决策。展开更多
文摘The Kou watershed, situated in the Southwestern part of Burkina Faso, has succumbed since a couple of decades in a typical theater play of anarchistic water management. With its 1800 km2, this small watershed holds the second largest city of Burkina Faso (Bobo-Dioulasso), a former State ran irrigated rice scheme and several informal agricultural zones. Despite the abundance on water resources, most water users find themselves regularly facing to water shortages due to an increase in population and low irrigation efficiencies. Local stakeholders are hence in need of easy-to-use and low-cost decision support tools for the monitoring and exploitation of the water resources at different spatial and user levels. A top-to-bottom string of adapted water management tools has been successfully installed to tackle the problems: from watershed (top) to field level (bottom), passing by the 1200 ha irrigation scheme. Land use maps have been derived from time-series of free satellite images. Combined with data from a network of hydrologic gauging stations, regional water use maps were established. SIMIS was put in place for the public-private management of the regions irrigated rice scheme. Day to day water use on irrigated plots was followed by soil humidity and crop canopy measurements. A simple field-cropwater balance model Aqua Crop was used by extension workers to draft optimal irrigation charts. Each tool was applied independently, requiring only limited data;but their combined results contributed to an improved integrated water management.
文摘雷电及操作过电压的识别,对改进和提高电力系统绝缘配合水平具有重要意义。提出了一种基于时频矩阵奇异值分解(singular value decomposition,SVD)和多级支持向量机(support vector machine,SVM)的雷电及操作过电压识别方法,通过对过电压信号的小波分解,构建多尺度时频矩阵,利用SVD对该矩阵进行奇异值分解,将信号分解到不同的时频特征子空间,然后获取过电压信号的奇异谱,并计算奇异谱的特征量,将这些特征量作为多级SVM的输入,实现雷电及操作过电压的辨识。对变电站实测5种过电压信号的计算表明:提取的特征量维数低,对过电压信号的电磁干扰具有相对稳定性;采用的识别方法训练次数少,识别率高,能够实现雷电及操作过电压的准确分类。
文摘针对模块化多电平换流器(modular multi-level converter,MMC)子模块开路故障特点,提出一种基于无监督学习-最小二乘互信息谱聚类和整体最小二乘支持向量机(total least square support vector machines,TLS-SVM)的故障诊断方法,前者用于故障特征信息提取,后者用于故障分类识别。在MATLAB/Simulink环境下,搭建可进行故障设置的201电平MMC仿真系统。对采集到的换流器正常和故障运行时的三相电流信号通过滤波去噪处理后,进行Hilbert包络分解得到包络均值,使用最小二乘互信息谱聚类对包络均值进行二分类并获得标签集,然后将标签集和数据集作为基于整体最小二乘支持向量机的训练集并获得分类模型,最后对MMC故障进行分类和识别。仿真实验结果表明,该方法能有效识别高电平MMC的开路故障,并能实现智能决策。
