# An Event-Driven Agent-Based Simulation Model for Industrial Processes
## 2 Process Model  
The industrial process model described in the present paper must be considered as a generic continuous process belonging to any industrial sector. A raw or semi-manufactured product must be further processed by several production lines in order to be sent to the market as a finished product. The production lines are organized in series, one after the other. These series represent the considered production process steps. Sometimes, one production step is developed by several equivalent production lines connected in parallel, i.e., performing the same working operations, namely, a product might be worked by any of these lines. For each production step, the plant provides a warehouse where products are stored before being worked. The above-described generic production process is schematically depicted in Figure 1.  
The exemplar production site depicted in Figure 1 is composed of three production steps, four production lines (two of them are equivalent) and four warehouses. The last step concerns the packaging and the products' delivery. Each warehouse has a limited storage capacity. A product might be moved inside a warehouse before being processed by a production line. Each production line is composed of different machines, each one with a limited buffer that represents the queue of the machine. In the current model, it is assumed that each production line is composed, at most, by one machine with a buffer maximum capacity of two products. A product, in order to be accepted and processed by a machine, needs firstly to be added to its production scheduling. This operation is usually performed at the beginning of the process, i.e., when the production scheduling is defined according to the production orders information, the available input materials, and the status of each machine. Nevertheless, the scheduling of a machine can change over time due to unexpected events such as faults, maintenance operations or machine overloading. Once the product has been accepted, it must be loaded into the machine's buffer, and then, it is ready to be worked. When the production line finishes processing the semi-finished product, it will be transported into the next warehouse and this scheme is repeated until the product reaches the delivery zone, where the product is loaded on a truck and shipped. In summary, a product undergoes the following steps during the process chain:  
1. Assigning the product to a machine's scheduling.
2. Moving the product within a warehouse.
3. Loading the product into a machine's buffer.
4. Working the product on a machine.
5. Stocking the product into a warehouse after processing.
6. \(<\)_Repeat phases \(C\), \(D\) and \(E\) until the last warehouse is reached\(>\)_
7. Loading the product to a truck to be shipped.
8. Delivering the product.  
As an example, Table 1 shows all the operations of the production process schematically depicted in Figure 1, together with the affected processes and the corresponding code assigned to the operations.  
Figure 1: Production process scheme.  
In the depicted exemplar case, only six main operations were defined, but it is clearly possible to extend the number of operations by adding new and specific ones.