摘要

In view of the importance of seasonal forecasting of agricultural commodity price, particularly vegetable prices, and the limited research attention paid to it previously, this study proposes a novel hybrid method combining seasonal-trend decomposition procedures based on loess (STL) and extreme learning machines (ELMs) for short-, medium-, and long-term forecasting of seasonal vegetable prices. In the formulation of the proposed method (termed STL-ELM), the original vegetable price series are first decomposed into seasonal, trend, and remainder components. Then, the ELM is used to forecast the trend and remainder components independently, while the seasonal-naive method is used to forecast seasonal components with a 12-month cycle. Finally, the prediction results of the three components are summed to produce an ensemble prediction of vegetable prices. In addition, an iterated strategy is used to implement multi-stepahead forecasting. In terms of two accuracy measures and the Diebold-Mariano test, the experimental results show that the proposed method is the best-performing method relative to the competitors listed in this study, indicating that the proposed STL-ELM model is a promising method for vegetable price forecasting with high seasonality.