A virtual factory teaching system in support of manufacturing education

Journal of Engineering Education, Oct 1998 by Dessouky, Maged M, Bailey, Diane E, Verma, Sushil, Adiga, Sadashiv, Et al

Figure 2 shows the first two windows of the prototype. Students can create their own factory or join an existing factory. The students' interaction with the VFTS depends on whether they are building or running a factory model. The former interaction is typically during the design time, while the latter is during the run time. Figure 3 shows the VF"T'S windows that create the factory. In the first window, the student enters the number of workcenters and whether the factory will be deterministic or stochastic. In the stochastic case, the input parameters are treated as random variables. The remaining windows allow the student to enter information on processing times, due dates, etc. For each workcenter, students can select a dispatching rule from a predefined list. The student also specifies the release rule, either push-based or zero inventory (a strict pull system).

During the run time, students execute simulations, change decsion parameters, and interact with other team members over a network using the built-in chat room. A complete factory model is fed into the simulation engine along with the simulation parameters. Figure 4 shows a sample simulation window and the control panel The students can see dynamic plots of factory status. Figure 5 shows the windows used in the creation and resulting plot of the number of jobs completed as a function of the simulation clock. At the end of a simulation run, outcome reports are broadcast to the team members.

IV. ASSESSMENT OF THE PROTOTYPE

To assess the pedagogical benefits of the VFTS, we tested its use in ISE 410 in the fall of 1997. Class performance was compared to that of the fall 1996 class, in which the VFTS was not implemented. The two classes covered the same material in the same order, were given similar quizzes, homework, and midterm examinations, took the same final, and were taught by the same professor at the same time of day using the same textbook. Thus, everything possible was done to maintain consistency across the two classes, with the exception of the introduction of the VFTS. Students in both classes filled out a survey on the last day of class which captured demographic data, study pattern information, self-assessment of learning outcomes, and interest in the subject matter (see table 1).

Because the VFTS prototype currently includes only a factory scheduling module, it was only introduced in the last month of the course coincident with the lectures on factory scheduling. Two homework assignments were similar in nature to the previous year's homework, except that in the 1997 class, students were to complement their hand calculations by setting up factories on the VF"TS, running simulations, and generating reports to verify their calculations. Students were grouped in pairs for the VFTS tasks, with each student given different system accessing capabilities so that particpation of both students was required to complete the assignment.

We expected that the VFTS would improve students' learning outcomes by helping them visualize complex factory dynamics. With the VFTS, students were able to build and analyze larger factories then they reasonably could by hand. It was thought that such large simulations would help students to better understand how Kanban policies change work-in-process (WIP) inventory patterns. This concept is difficult to convey in lectures, which were the primary mode of presentation to the 1996 class. Both classes also performed in-class physical simulations using pennies to represent jobs advancing through workstations, but these simulations involved only four workstations with one machine each. Thus, the VFIS added several features to the learning process: scale, simulation with animation, factory creation, and teamwork.