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. © 2020, Editorial Board of Journal of Systems Engineering Society of China. All right reserved.