For years the use of simulation in education environments has been appreciated. Also at the Eindhoven University of Technology (TU/e) simulation with ENTERPRISE DYNAMICS (ED) is used in courses.

The main purpose of the course "Design of Operational Planning and Control Systems" is to develop a Operations Planning and Control concept for a production system presented in a business case. Currently the students have to evaluate and validate the proposed design using spreadsheets. It is quite complex to perform such an evaluation with a static spreadsheet solution. Hence there is a cherished wish to introduce simulation in this course as the appropriate method to support students.

The effort needed to build a model of a value adding process structure with corresponding control system in basic simulation tools is quite high, while the dynamics and flexibility of the model is relatively low. As the emphasis of the course lies with the design and evaluation of the control system instead of creating a simulation model, an important condition for using simulation was that the effort needed to build the model was minimized. Therefore TU/e proposed to develop and use a simulation application that could be used for modeling and analyzing a control system as designed by the student for many different environments.


TU/e desired a tool with the following features:
  • High flexibility with respect to system structures that can be analyzed;
  • Automated building of system structures consisting of standard building blocks;
  • High flexibility with respect to controlling all elements within the system;
  • High user friendliness, enabling students (even without programming skills) to analyze complex systems.
For these reasons a system had to be build using the lowest entity that is essential from an operations planning and control perspective: a process, being a unique combination of input materials, resources, time properties and output.

After a thorough specification and conceptualization phase, a tool was developed consisting of the following components:
  • Input database in Microsoft Access with input forms, in which the structure of the system is defined;
  • Tutor component within ED, to enable tutors to build (and adjust) the structure of the system from the database in ED and provide useful decision rules and algorithms the students can choose from;
  • Student component within ED, to enable students with the aid of GUI's to choose their control over the system from the rules defined by the tutor or, when more experienced, define their own decision rules.
For each business case the tutor provides the structure of the system in the input database. The structure can be build up from materials, processes, resources and stock points. All relevant properties (e.g. process time, resource failure, process batching) of these building blocks are also defined in the input database. The application loads the structure from the database into ED and builds up the simulation model automatically.

The next step is to provide useful decision rules, which the students can use in their control and analysis of the system. The tutor defines decision rules for the following aspects:
  • Resource planning (e.g. amount, work hours, overtime);
  • Demand acceptance;
  • Work Order generation;
  • Order releasing;
  • Stock point replenishing algorithms (e.g. s/Q, R/S).
All settings can be adjusted within the control functionality.

After the tutor has defined all desired decision rules, the model with its designed structure and the available decision rules can be saved and handed over to the students. The students can now implement their design of the goods flow control, using the decision rules predefined by the tutor. The parameters within these decision rules can still be adjusted by the students. For more experienced students, it is still possible to define their own decision rules.

Apart from the available control settings, available through these algorithms, the student also has to define the demand behavior for the end products produced by the system. By running the model with the designed control system and releasing the defined demand, it will produce the end products. The resulting performance of the system is dependent on the designed control structure.
The simulation model returns raw output data of all elements in the system and exports it to Excel. The students use this raw data to analyze the performance (e.g product lead-time, product availability) of their control strategies.
Since the emphasis of the application lies with the combination of a user-friendly way of simulating value and supply chain management and high flexibility of the designed structure, the tool can handle a wide range of structures with corresponding controls. Therefore the tool can not only be used for educational purposes, but also for evaluating business cases in practice.