Quadratic time-varying parameters discrete grey model.

Based on the reason that the growth of discrete grey model is constant, the paper structured quadratic time-varying parameters discrete grey model (referred to as QDGM(1,1)) by introducing quadratic time-varying terms. And then the paper researched properties of the new model, and reached the conclusion that QDGM(1,1) possessed white exponential law coincidence, linear law coincidence, quadratic law coincidence and consistency of stretching transformation. What's more, the paper applied optimization method to optimizing the iterative starting value of the new model, and introduced the steps of using QDGM(1,1) to predict. Finally, the new model was compared with another three discrete grey models through an instance. It was proved that the new model greatly improves the simulation and prediction precision. [ABSTRACT FROM AUTHOR]