系统动力学运算过程图分析方法——以供应链模型参数调控延迟计算为例

针对系统动力学仿真方法存在的两个问题，一是仿真结果的数值输出，其数值大小动态变化过程直观性差，不利于理解与应用；二是因仿真程序内涵与计算过程被隐藏，使得流图模型的因果链、仿真方程、仿真程序、仿真数值结果间的内在关系不能较好地展示出来.论文以供应链模型的仿真数值输出为例，首先将流图的因果链与仿真方程相结合建立运算因果链，将运算因果链与仿真方程相结合建立数据过程顶点，进而将数据过程顶点集合与运算因果链组合成"运算过程图"，展示变量顶点值计算过程，解决仿真数值输出难以理解的问题.接着，进行单参数调控延迟量的仿真规律研究，推导出单参数调控延迟量计算的2个定理，为相关参数调控的延迟计算及理论分析提供依据.文章提出的运算过程图具有3个功能：1）直观展示仿真数值计算过程；2）揭示系统动态变化规律，为模型仿真规律展示和研究提供一个新平台；3）验证系统动力学模型的可靠性.

Operation process gragh analysis approach of system dynamics — Illustrated by calculation of the delay regulated by parameters in a supply chain

At present, there are still two problems in the simulation method of system dynamics. First, it is difficult to reveal the dynamic change rules from data results because the connotation and calculation process of the simulation are hidden. Second, the intrinsic relationship among causal chain, simulation equation, simulation program and simulation results of flow diagram model cannot be well demonstrated. This paper takes the numerical simulation results of a supply chain SD model as an example, combining with simulation equation and the causal chain to establish operation causal chain. Then, it combines operation causal chain and simulation equation to establish the data process vertices, and combines the data process vertices and operation causal chain into the operation process graph. The variable peak value calculation process makes numerical simulation output tobe easily comprehensible. Then, the simulation regular of single control-parameter time-delay is studied to deduce two theorems, which provide the basis for the calculation and theoretical analysis of the time-delay quantity of related control-parameter regulation. The operation process gragh process graph presented in this paper has three functions: 1) to visually show the process of numerical simulation; 2) reveal the dynamic regular of the system and provide a new platform for the demonstration and research of model simulation regular; 3) show the reliability of the System Dynamics model.