私密直播全婐app免费大渔直播,国产av成人无码免费视频,男女同房做爰全过程高潮,国产精品自产拍在线观看

Multivariate calibration including linear and non-linear methods has been widely used in the spectral quantitative analysis of complex samples. Despite the efficiency and few parameters involved, linear methods are inferior for nonlinear problems. Non-linear methods also have disadvantages such as requirement many parameters, time-consuming and easily relapsing into local optima though the outstanding performance in nonlinearity. Thus, taking the advantages of both linear and non-linear methods, a novel algorithm called extreme learning machine (ELM) is introduced. The efficiency and stability of the method are investigated firstly. Then the optimal activation function and number of hidden layer nodes are determined by a new defined parameter, which took into account both predictive accuracy and stability of the model. The predictive performance of ELM is compared with principal component regression (PCR), partial least squares (PLS), support vector regression (SVR) and back propagation artificial neural network (BP-ANN) by three near-infrared (NIR) spectral datasets of diesel fuel, ternary mixture and blood. Results show that the efficiency of ELM is mainly affected by the number of nodes for a certain dataset. Despite some instability, ELM becomes stable close to the optimal parameters. Moreover, ELM has better or comparable performance compared with its competitors in the spectral quantitative analysis of complex samples.