Research paper


At the department of Education at the University of Twente, Enschede, The Netherlands some universal design systems have been developed in the period 1984-1989, with which a trained courseware designer can make computer simulation programs in the fields of physics, biology, medical science, and economics. Technical installations or plants are also excellent subjects for this type of simulation. The educational computer simulation programs created with these systems, are characterised by a highly graphic interface. One of the design systems which was used was MacTHESIS and the design method which was used to develop computer simulation programs with this system was the so called 'MacTHESIS philosophy'.

Research with some twenty computer simulation programs and analysis of the results, showed that proper instruction beside the simulation was indispensable. Further research led to a theory that has been called the Parallel Instruction theory.


The MacTHESIS philosophy behind the computer simulation programs of Min et al. is described and showed in products on many conferences (Min et al., 1987 and 1992; Van Schaick Zillesen, 1990). The design environment, the teacher environment, and the learning environment, each have their own characteristics design parameters and a simple human-computer interaction. A complete simulation learning environment consists a large serie of elements. The most important elements are:

All these elements should be (parallel) available to the student. Some elements must be presented on-line (CBT materials) others can be off-line (paper instructions). The University of Twente investigates the balance between the simulation parts and the instruction parts.

Figure 1. The Parallel Instruction theory is based on the concept that in a simulation environment everything should be in view, even the paper materials. Apart from the graphic output of the computer simulation program, also the instruction program, possibly a help system or a video window ('model-driven desktop video') and the paper instruction materials are in sight.

Min (1990) has developed and researched various instruction methods for use parallel to his simulation programs. Even the vizualized conceptual mathematical model plays an important, special role in the instruction in the learning environment. The 6 important instruction methods for parallel use as you can see in figure 1, are:

The earliest simulations had no more than a graphic output on a screen, the instruction in relation to the computer simulation program was given in a separate textbook with or without loose worksheets. MacTHESIS, a computer simulation system developed at the University of Twente, partly solved this problem of paper materials by creating an extra window, parallel with the program on which a survey appeared of the visualized, underlying mathematical model, allowing for intervention at the same time. This rather simplified form of instruction required other paper materials as well.

In 1989 Van Schaik Zillesen and Min developed an instruction system that only could switch computer programs off and on, from CBT instruction program to simulation program and reverse, with or without parameter passing. The simulation program appeared and the instruction disappeared. This instructional system was built with HyperCard. Authorware Professional (Course of Action) was also investigated and proved to be a good solution too. This method was called the sequential presentation (or instruction) method. (Van Schaick Zillesen 1990).

Through the arrival of a new multi-tasking operating system like Macintosh MultiFinder and later System 7, interesting techniques became available for organizing learning environments, others then which the so-called sequential presentation or instruction method. At the same time simulations were investigated that were running on several monitors parallel connected to one Macintosh II computer. The researchers developed together with their students a computer simulation program for a chemical multinational in The Netherlands, AKZO at Hengelo, embedded in a coached learning environment. Initially it was the sequential presentation method but later on it became a system offering an overall view, based on the MacTHESIS philosophy. This program was a simulation of the brine purification factory and it could be used for operator training and the instruction of chemical laboratory technicians. The instructional shell functioned both as an instruction and a help system. Through this project we found important design methods which led to the theory here described. Analysis of all these activities and experiences led to the what we called 'Parallel Instruction' theory (the PI theory) for computer simulation environments. See figure 2. All this is based on earlier design theories and methods.

Figure 2. The Parallel Instruction theory has been developed in the course of research and analysis of phenomena occurring during observation of testees who were working with computer simulation programs, based on the MacTHESIS philosophy.


Elaborating on the MacTHESIS philosophy and earlier design methods for the furnishing of a learning environment for simulation, we realised over the past years besides the program BRINE PURIFICATION, in cooperation with AKZO Hengelo, a chemical company in Twente, a large number of other simulations and learning environments. With the MacTHESIS system and the parallel windowing technique the programs LEMMINGEN, VIJVER, CELLEN and CARDIO were made, and with the THESIS system, with sequential windowing techniques, PERCH, CARDIO and FLUIDS. These last two programs were equipped with small help systems which actually functioned as an instructional method to coach the particular case possibilities of the programs.

Under the GEM user interface system on Atari computers and later MS.DOS computers, the program FLOWSIM was made by Delft Hydraulics, in cooperation with the University of Twente (Zwart, 1988), that could open and close independent windows in a conceptual scheme of a flowing river which appeared on the full screen. These programs were inspired by the MacTHESIS system and the MacTHESIS philosophy.

There are more experiments and simulation projects in cooporation with others, but the most important programs on which our conclusions about the Parallel Instruction theory are based are showed in table 1.

Ter Hedde, a student of the University of Twente, developed a computer simulation program for Fokker Space & Systems in Amsterdam, called INSAN / SATSIM, with viewports techniques (fixed parts of the screen in which animation objects were presented), without windowing techniques, in which project we could conclude that users want to have a lot of information parallel.

For the program BRINE PURIFICATION we developed an extensive CBT instruction program which could be implemented on a ordinary MacIntosh II computer, or on a multi-monitor MacIntosh II computer with the MultiFinder. See figure 3. The remaining instructions were given in a small instruction manual. For the MacTHESIS software LEMMINGEN, VIJVER and CELLEN (Gritter, Koopal and Siteur, 1990) an overall instruction program was developed in which all these simulation programs could be embedded.

Figure 3. The computer simulation program BRINE PURIFICATION for AKZO Hengelo, was the onset to the development of the PI theory. This program runs on a MacIntosh II computer (as a task in the MultiFinder) with three interconnected monitors, it has three movable pages (windows), one instruction program (as a parallel task), and a user manual.

The results of these experiments and investigations showed that sequential presentation instruction methods were far too rigid and had a great number of shortcomings. The same shortcomings as in tutorial courseware, viz. that open learning environments are reduced to old-fashioned computer controlled learning environments. The computer program PERCH (Mous, 1989) is a length and age structured gillnet fisheries program, designed with the THESIS system for MS.DOS computers without windows but with fixed view ports on the screen. Recently we incorporated an advanced video technique in the MacTHESIS system, version 5.0, for desktop video fragments controlled by the computer simulation program, called: 'model-driven desktop video'.


It turned out that for a large number of pupils and trainees everything in a learning environment should be within reach and crystal clear. This was already well known for simulations as descriped by Coleman, Miltenburg and Hartsuijker, but technically hard to realize by courseware writers or most of the educational software houses (Van Schaick Zillesen, 1990; Min, 1992). With tutorial CBT materials it is known that certain pupils are annoyed by the disappearance of the subject matter which has been read. Technically speaking calling back text which has been read is for almost all tutorials still problematic or not common sence. The problem with separate paper materials is that students and trainees think they can do without. Even teachers tend to think so. As a result beautiful computer simulations remain unused at schools, in spite of the perfect design, styling and user-interface. Our earlier learning environments are characterized by modern input and output techniques and a wide range of different kinds of visualizations, from abstract to concrete. In spite of all that it turned out that the instruction method was the decisive factor. MultiMedia and HyperText techniques of in particular Macintosh computers, and the MacTHESIS system and philosophy, made it possible to prove our theories.

The main purpose of educational computer simulations is to help students to construct mental models of dynamic processes. We don't know the how such a mental model in our head looks like, we do know how experts organize there knowlegde of processes. We assume there is a relation between the knowlegde and the external representations (Li, Jones and Merrill, 1990) and that instruction that corresponds to the external format experts use facilitate the construction of mental models by students . Elements in the knowlegde representation of processes are:

The strength of traditional computer simulation is in the last element: the relations. Because of the active involvement of students and the required mental processing in building these relations computer simulations are superior to other forms of learning. A complete learning environment with computer simulations should provide parallel to the core simulation instructional possibilies on the other elements of the dynamic proces. This instruction should include:

This instuction should always be accessible to students. Because of the nature of simulations we believe that compulsory instruction can cause cognivite dissonance and should be avoided.

Using the Parallel Instructional theory and the MacTHESIS system will yield optimal results. This integrated instructional equipment will be easier to use for most students, and a deeper level of understanding will be achieved. The teacher has a wide range of tools to modify and change the instruction materials as well as certain aspects of the computer simulation program, e.g. the visualization of the conceptual model, some texts and default positions of pages (windows).


Investigations with the programs and the PI theory have resulted in a new MacTHESIS system, version 5.0. With the PI theory and this MacTHESIS system, MacTHESIS software can be complemented with programs based on 'parallelism'. The total of this R&D work is accompanied by the MacTHESIS philosophy. The design method based on this theory we have called the PITS (Parallel Instructional Theory for Simulation) method.

Students of the University of Twente can follow three courses in which they learn the PI theorie, the MacTHESIS philosophy and the PITS design method. So the basis of this type of courseware to built new simulation environments based on the Parallel Instruction theory is large.


The author gratefully acknowledge the contributions of B. Reimerink, P. G. v Schaick Zillesen, W.J. Zwart (co-workers of the University of Twente), A. Verstraete, S. van Duin (students of the University of Groningen), T. Mous (University of Wageningen) and: G. Gritter, W. Koopal, I. Siteur, J. Lanzing, C. v Delft, R. Ter Hedde, D.P. Flach, I. Klein Teeselink, M. Gmelich Meijling (students of the University of Twente, Enschede). P. G. v Schaick Zillesen now working at the University of Wageningen, the Netherlands.


M. Sc thesis and other (mostly internal publications and in the Dutch language) about the work of Zwart (1988), Ter Hedde (1989), Mous (1989), Gritter (1990), Koopal (1990), Siteur (1990), Lanzing (1992) and Van Delft (1992) are avialable to the author.


Min, F. B. M., Renkema, M., Reimerink, B., and Van Schaick Zillesen, P. G. (1987). MacTHESIS: A design system for educational computer simulation Proceedings of the EURIT 86 conference, Pergamon, London (Tj. Plomp and J. Moonen (Eds)) pp 689-691

Min, F. B. M. (1990). Computer Simulation for a Chemical Plant with Hypermedia 4th International Conference: Computer and Video in Corporate Training; IDMI Technology Transfer programme: Instituto Dalle Molle di Metodologie Interdisiplinari (IDMI), George Manson University and Ass. for the Development of Comp. Based Instructional Systems (ADCIS); pre-print, Lugano, Itali (Th. Bernold and J. H. Finkelstein (Eds)) pp. 143-146

Min, F. B. M. (1992). From Model to Program: Computer Simulation for Learning, Teaching and Training; Models, Programs and Systems; Offered for publication to some publishing companies, Internal publication: University of Twente Enschede, Holland.

Van Schaick Zillesen, P. G. (1990). Methods and techniques for the design of educational computer simulation programs and their validation by means of emperical research. Academic thesis, Internal publication: University of Twente Enschede, Holland.