Simulating continuous time production flows in food industry by means of discrete event simulation

The paper presents a new framework for carrying out simulations of continuous-time stochastic processes by exploiting a discrete event approach. The application scope of this work mainly refers to industrial production processes executed on a continuous flow of material (e.g. food and beverage industry) as well as production processes working on discrete units but characterized by a high speed flow (e.g. automated packaging lines). The proposed model, developed adopting the Discrete EVent system Specification (DEVS) formalism, defines a single generalized base unit able to represent, by means of an event scheme generated by state changes, the base behaviors needed for the modeling of a generic manufacturing unit, that is, (i) breakdowns and repairs, (ii) speed and accumulation, and (iii) throughput time. Moreover, the possibility to keep trace of additional measures of parameters related to the process and the flowing material (i.e. temperature, concentration of pollutant, and so on) is also considered. Since these parameters can change over time in a continuous manner, a specific discretization approach has been introduced to avoid the need to integrate parameter variation functions over time.