针对短时交通量的非线性和时变性,提出一种基于粒子群—小波神经网络的预测方法。该方法以前馈多层感知器的神经网络拓扑结构为基础,将预测误差反向传播,经粒子群优化算法对神经网络连接权值进行修正。隐含层神经元选择Morlet母小波基函数作为激活函数,利用小波分解分离短时交通量的高频部分和低频部分,防止高低频数据之间的过度影响,进一步提高预测的精度。根据最简化结构概念对神经网络结构进行泛化,确定最优网络结构,提高预测的速度。通过实例预测显示,该方法预测精度高,预测速度快,能够满足实际工程的要求。
For nonlinearity and time variance of short-term traffic volume, a kind of forecasting method named PSO(particle swam optimization)-wavelet neural network is proposed. The method is based on topological structure of multilayer feed-forward perceptrons (MLPs), and the output error is back propagated to PSO module to revise connection weights of network. In the hide-layer, Morlet mother wavelet function is selected to be neuron active function which separate high-frequence and low-frequence of traffic volume data to avoid the effect between each other. The network generalizes by minimization feature structure(MFS) concept to a optimal structure to improve forecasting speed. The forecasting example shows, the accuracy and speed of the method proposed are suitable for practical engineering.