Grey wave forecasting with qualified unequal-interval contour lines and its application in metal prices prediction

This paper proposes a modified grey wave forecasting method for time series with irregular fluctuation ranges. This method uses quantile to define the contour lines and forecast future values based on contour time sequences decided by qualified unequal-interval contour lines. For the empirical analysis, this paper uses monthly prices of two metals - nickel and zinc -to assess the forecasting performance of modified grey wave forecasting model. The empirical analysis indicates that the modified grey wave forecasting method is better than original grey wave forecasting method in prediction accuracy and computational efficiency.