On the basis of the analysis about present water resource situation in China,the disadvantage of the for- mula of flow loss and water using coefficient on anti-seep channel which have been applying in channel de- sign...On the basis of the analysis about present water resource situation in China,the disadvantage of the for- mula of flow loss and water using coefficient on anti-seep channel which have been applying in channel de- sign and water saving irrigation administration will be indicated in the paper. The characteristics of that the loss of conveying water is changeable with the now changing have been take into account in the new formula. The formula is validated by the example of middle permeable channel (A=1.90,m=0.40). The calculate re- sult is more precision. Also some formula has been given,they can be referred to the worker of the irrigation administration.展开更多
为更精确地预测航班过站时间,将全国机场按照规模差异及不同地理位置所导致的客流量差异和天气差异对航班过站时间造成的不同影响进行分类,基于各类机场航班数据,构建混合轻量级梯度提升机算法(LightGBM)模型对航班过站时间分类预测。...为更精确地预测航班过站时间,将全国机场按照规模差异及不同地理位置所导致的客流量差异和天气差异对航班过站时间造成的不同影响进行分类,基于各类机场航班数据,构建混合轻量级梯度提升机算法(LightGBM)模型对航班过站时间分类预测。引入自适应鲁棒损失函数(adaptive robust loss function,ARLF)改进LightGBM模型损失函数,降低航班数据中存在离群值的影响;通过改进的麻雀搜索算法对改进后的LightGBM模型进行参数寻优,形成混合LightGBM模型。采用全国2019年全年航班数据进行验证,实验结果验证了方法的可行性。展开更多
随着配电网复杂性日益增加以及对电能质量要求不断提高,谐波污染和网络损耗已成为影响新型电力系统稳定性和运行效率的关键因素。通过同步优化电容器和有源功率滤波器(active power filter,APF)的配置,实现谐波抑制与网络损耗最小化的...随着配电网复杂性日益增加以及对电能质量要求不断提高,谐波污染和网络损耗已成为影响新型电力系统稳定性和运行效率的关键因素。通过同步优化电容器和有源功率滤波器(active power filter,APF)的配置,实现谐波抑制与网络损耗最小化的双重目标。利用谐波功率流分析模型进行谐波评估,根据谐波穿透法进行频域建模。对失真配电网络中的电容器和APF的同步配置建模,利用粒子群优化(particle swarm optimization,PSO)算法解决电容器和APF同步配置的混合整数非线性规划问题。实验结果表明:适当配置电容器和APF能够显著改善网络的电压质量,所提的同步优化方法不仅在降低系统成本的同时,显著提高了新型电力系统配电网的电能质量和运行效率。展开更多
文摘On the basis of the analysis about present water resource situation in China,the disadvantage of the for- mula of flow loss and water using coefficient on anti-seep channel which have been applying in channel de- sign and water saving irrigation administration will be indicated in the paper. The characteristics of that the loss of conveying water is changeable with the now changing have been take into account in the new formula. The formula is validated by the example of middle permeable channel (A=1.90,m=0.40). The calculate re- sult is more precision. Also some formula has been given,they can be referred to the worker of the irrigation administration.
文摘为更精确地预测航班过站时间,将全国机场按照规模差异及不同地理位置所导致的客流量差异和天气差异对航班过站时间造成的不同影响进行分类,基于各类机场航班数据,构建混合轻量级梯度提升机算法(LightGBM)模型对航班过站时间分类预测。引入自适应鲁棒损失函数(adaptive robust loss function,ARLF)改进LightGBM模型损失函数,降低航班数据中存在离群值的影响;通过改进的麻雀搜索算法对改进后的LightGBM模型进行参数寻优,形成混合LightGBM模型。采用全国2019年全年航班数据进行验证,实验结果验证了方法的可行性。
文摘随着配电网复杂性日益增加以及对电能质量要求不断提高,谐波污染和网络损耗已成为影响新型电力系统稳定性和运行效率的关键因素。通过同步优化电容器和有源功率滤波器(active power filter,APF)的配置,实现谐波抑制与网络损耗最小化的双重目标。利用谐波功率流分析模型进行谐波评估,根据谐波穿透法进行频域建模。对失真配电网络中的电容器和APF的同步配置建模,利用粒子群优化(particle swarm optimization,PSO)算法解决电容器和APF同步配置的混合整数非线性规划问题。实验结果表明:适当配置电容器和APF能够显著改善网络的电压质量,所提的同步优化方法不仅在降低系统成本的同时,显著提高了新型电力系统配电网的电能质量和运行效率。
