【作者】 白世贞； 王文利；

【Author】 Shizhen Bai , Wenli Wang ( Southeast University, Nanjing 210096, China) ( Harbin University of Commerce, Harbin 150076, China)

【机构】 东南大学； 哈尔滨商业大学；

【摘要】 仿真技术作为处理系统不确定性的有力工具越来越受到人们的重视,它是通过运行具体仿真模型和对计算机输出信息的分析,实现对实际系统运行状态和变化规律的综合评估与预测,进而实现对真实系统设计与结构的改善或优化。可见,系统仿真的关键在于建立系统模型。传统供应链系统模型大多是建立在离散事件系统基础上,即将供应链系统中的变量抽象为离散出现的事件,研究事件之间的不确定性。但是由于供应链系统的复杂性,在运用离散事件系统建模尤其是对供应链战略层建模时,会涉及到大量的输入数据,仿真的事件调度表中也会存在大量的事件,这样大大降低了仿真效率,并且体现不出供应链物流系统中连续的部分。于是开始有学者试图用连续系统来描述供应链,但是由于供应链中存在着大量的不确定性因素,并且供应链中决策主体具有分布性和自治性特点,因此很难建立起描述整个供应链的动力学方程。更多还原

【Abstract】 Simulation technology is becoming more and more important as a powerful tool of analyzing uncertainties of system. It runs simulation model and analyzes output information with computer in order to evaluate operating state and forecast developing trend or design, improve and optimize structure of actual supply chain system. The key of system simulation is building simulation model. Most supply chain simulation models have been developed on the basis of discrete event system, regarded variable of system as event appears at discrete time point and been researched uncertainty among events. However, the actual model of a supply chain is large scale and requires large amounts input data. It is difficult to run with large number of events in event scheduling table and impossible to reflect the continuous nature of supply chain especially modeling in strategic level. In recent years, several scholars have researched on supply chain using continuous system simulation tool, but it has never built precise dynamical equation because of so many uncertainties and distributed and autonomic characteristics of decision-making agents in supply chain. Supply chain systems are neither completely discrete nor continuous, but hybrid dynamic systems composed of discrete elements and continuous elements, mainly discrete elements. Only discrete-continuous combined modeling can actually reflect dynamic relationship of many elements in supply chain. Petri net has particular advantage in simulating discrete event system and can denote sequence of activities, batch, asynchronous and subsequent program in supply chain system conveniently. But Petri net can’t describe discrete-continuous hybrid systems direct, so it must be extended. In this paper, a supply chain hybrid Petri nets model is built using discrete-continuous combined modeling approach. We obtain optimal firing speed of continuous transitions by maximizing the difference between firing speed of external transition and firing speed of internal transition to obtain maximal output at the cost of minimal input and obtain optimal firing sequence of discrete transitions in the model by balancing transportation costs and stock costs. This paper uses Visual Object Net++2.0 to simulate supply chain hybrid Petri nets and supply chain discrete Petri net and compares simulation results of inventory level alteration of manufacturer’ parts and a distributor’s orders fulfilling. We get the conclusion that hybrid Petri nets simulation is superior to discrete Petri net simulation.更多还原