模型是现实的缩影或抽象化。按其性质,可把模型分为解析模型(Analytic Model)和模拟模型(Si-mutation Model);按其形式,可把模型分为概念模型(Conceptural Model)、图解模型(DiagrammaticalModel)、实体模型(Concrete Model)、数学模型(Ma-thematieal Model)和计算机模型(Computer Model)等。所谓数学模型就是将系统的有关因素和参数及其相互关系归纳成一个或一组数学方程,用来反映 The model is a microcosm or abstraction of reality. According to their nature, the model can be divided into Analytic Model and Si-mutation Model. According to its form, the model can be divided into Conceptural Model, Diagrammatical Model, Concrete Model, Ma-thematieal Model and Computer Model. The so-called mathematical model is the system of relevant factors and parameters and their correlation into one or a set of mathematical equations used to reflect