为提高超短期风速预测的可靠性和准确性,将被预测地点(本地)周边测风塔风速风向等当前和最近历史观测值作为基础数据,采用空间相关性来预测本地的未来风速。首先,依据风向和风速的延迟相关性,挑选出上游测风塔。之后,结合最优延迟时间,...为提高超短期风速预测的可靠性和准确性,将被预测地点(本地)周边测风塔风速风向等当前和最近历史观测值作为基础数据,采用空间相关性来预测本地的未来风速。首先,依据风向和风速的延迟相关性,挑选出上游测风塔。之后,结合最优延迟时间,利用各上游和本地最近的风速观测值来训练预测模型。最后,将各上游风速的当前观测值输入模型,即可得到本地的风速预测值。以偏最小二乘回归(partial least squares regression,PLSR)为主要模型,并采用线性回归(linear regression,LR)、最小二乘支持向量回归等模型进行对照。以冬季风时期的荷兰Huibertgat和天津为被预测地点,进行了PLSR、LR预测误差与模型阶数、样本容量之间关系的数值实验。研究表明,在冬季风时期,当样本容量达到一定程度后,预测误差的变化对阶数、样本容量和模型的类型均不再敏感。这表明空间相关性是一种较为可靠的超短期风速预测方法。展开更多
Oil holdup of oil-water two-phase flow was measured by using platinum resistance based on the fluid thermal balance equation.In order to improve the measurement accuracy of oil holdup,the effects of the electrical hea...Oil holdup of oil-water two-phase flow was measured by using platinum resistance based on the fluid thermal balance equation.In order to improve the measurement accuracy of oil holdup,the effects of the electrical heater fore-and-aft temperature difference of platinum resistance and total oil-water flux on oil holdup were researched.A least squares support vector machine(LSSVM)model with parameters optimized by genetic algorithm(GA)was proposed,the temperature difference and total flux of oil-water two-phase flow were used as inputs,and the oil holdup was used as output of the LSSVM model and the ideal model of oil holdups was obtained.The oil holdup model based on least squares support vector machine and genetic algorithm(LSSVM-GA) was compared with the theory corrected model and good oil holdup measurement results were obtained.The average measurement error was 0.96% in the range of 5% to 60% oil holdup.展开更多
文摘为提高超短期风速预测的可靠性和准确性,将被预测地点(本地)周边测风塔风速风向等当前和最近历史观测值作为基础数据,采用空间相关性来预测本地的未来风速。首先,依据风向和风速的延迟相关性,挑选出上游测风塔。之后,结合最优延迟时间,利用各上游和本地最近的风速观测值来训练预测模型。最后,将各上游风速的当前观测值输入模型,即可得到本地的风速预测值。以偏最小二乘回归(partial least squares regression,PLSR)为主要模型,并采用线性回归(linear regression,LR)、最小二乘支持向量回归等模型进行对照。以冬季风时期的荷兰Huibertgat和天津为被预测地点,进行了PLSR、LR预测误差与模型阶数、样本容量之间关系的数值实验。研究表明,在冬季风时期,当样本容量达到一定程度后,预测误差的变化对阶数、样本容量和模型的类型均不再敏感。这表明空间相关性是一种较为可靠的超短期风速预测方法。
文摘Oil holdup of oil-water two-phase flow was measured by using platinum resistance based on the fluid thermal balance equation.In order to improve the measurement accuracy of oil holdup,the effects of the electrical heater fore-and-aft temperature difference of platinum resistance and total oil-water flux on oil holdup were researched.A least squares support vector machine(LSSVM)model with parameters optimized by genetic algorithm(GA)was proposed,the temperature difference and total flux of oil-water two-phase flow were used as inputs,and the oil holdup was used as output of the LSSVM model and the ideal model of oil holdups was obtained.The oil holdup model based on least squares support vector machine and genetic algorithm(LSSVM-GA) was compared with the theory corrected model and good oil holdup measurement results were obtained.The average measurement error was 0.96% in the range of 5% to 60% oil holdup.
