TECHNICAL CONCEPTS

Chapter 2. Aspects of instrumentation and simulation technology

This chapter covers the following topics:

2.1 Introduction

In this chapter computer simulation will be discussed as an instrument and as one of the forms of Computer Assisted Learning (CAL) or Computer Based Training (CBT). In schools the term CAL and CAI were mostly used; in training situations the term CBT is more common. The definitions needed for this and the criteria will be dealt with step by step. Nowadays the term multimedia and hypertext systems is more usefully. Subjects for discussion will be: didactics, applied didactics, instrumentation technology, didactic apparatus, common interactive software, educational software, multimedia, hypertext systems, presentation techniques, acceptation techniques, and communication techniqueswhich play a part in educational software, designing aids like editors, designing environments, educational environments and finally computer simulation as an educational tool including interactive computer animation. Sometimes the terms CAL or courseware will be used instead of software.

Since the microcomputer came into existence, instrumentation technology in didactics is fully in the picture and it has made rapid progress as a subject. An instrument in education was formerly a passive, collective audio-visual apparatus for classroom teaching. Nowadays attractive educational tools exist, like all sorts of interactive discovery environments, in which the pupil himself can be individually active in learning. Instrumentation technology has become a valuable scientific discipline within (applied) educational science and also because of it. See figure 2.1.



The multimedia and hypertext systems were born. At the same time the terms educational engineer, instrumentation technology and simulation technology were created in educational science. The educational engineer approach is not so much the approach which Plomp and Verhagen (Lagerweij & Vos, 1987) advocate in the so called educational technology model; in Dutch: the OKT model. The educational engineer appears to be a mixture of a technical designer and a teacher of applied education. This method about educational technology for designing (the OKT model) could work to design something in which known techniques are used. These methods fail in times of new techniques in making modern courseware or multimedia projects are introduced.

However, if new techniques or new media are being used, creative thinking will be increasingly necessary and one can not achieve much with such standard methods. It is then necessary to free oneself from it. Optimum design is only possible when the development is already in process. During the designing process all sorts of thoughts crop up which are essential for the final product. This approach has been developed by Min & Zwart and was published by Moonen (Zwart, 1988; Moonen, 1990). Both visions of the educational engineer approach have become accepted in applied educational science, but not in didactics in general.

Training programs, Computer Assisted Learning, computer simulation programs, interactive video, but also linear video, film and other educational appliances are becoming increasingly important for business training in concerns. Annually billions of dollars are spent on educational training by companies. This amount is increasing steadily. Therefore technology applied for teaching purposes as mentioned above and for professional educational technologists has a great future.
There are tree fields in which simulations are used:

Figure 2.1 gives the relation between non-educational simulation, simulators for training and simulation for open learning environments in the field of multimedia, interactive software, instrumentation technology and the applied educational science, inside the educational sciences. Non-educational simulations are simulations in the research in a special domain of knowledge: mostly research to modelling the reality in a special domain. Simulators for training are apparatures with a computer, but mostly with model-driven mechanical components as showed in chapter 1. Figure 2.2 gives an example of a compact, turn-key simulation on a cheep handsome computer for open learning environments. Later on in chapter 3 more complex simulations, embedded into instruction programs and with more complex hardware will be described.

Nowadays the object or field of study in instrumentation technical research are the computer-based interactive individual educational tools. On the side of the audio-visual appliances, interactive video and on the side of the computer are computer animation, computer games and particularly in this respect, educational computer simulations. Integration of both systems is to see in the field of hypertext, multimedia and desk top video. These types of appliances will not look like a computer but like educational appliances, without useless extras. At present the types of scientific research occurring most often in instrumentation technology are:

The first type of this kind of research is here called 'performance research'. An example is research into the possibilities of Apple Macintosh for educational computer simulation and animation purposes. Research of the latter type usually results in theories which are realized in systems with which these theories can be tested. From this emerges an important proposition with respect to this book, namely: systems are materialized theories. Theories about certain generalities in kinds of objects (e.g. computer simulation and mathematical models) lead to systems (e.g. the 'THESIS' computer simulation design systems) that allow a test of these theories in practice in the laboratory or in class (e.g. the computer simulation programs that are made according to a certain method and with a certain designing system). Chapter 3 deals with some computer simulation systems which can instrument 95% of the present kinds of simulation in aid of a didactic situation.

Instrumentation technology is of a highly interdisciplinary kind. Knowledge and procedures derived from fields such as psychology, informatics, didactics, ergonomics and the theory of communication come together and are integrated. In applied educational science there is yet another discipline in which multimedia is used much, viz. instruction technology. See figure 2.1. Here psychologists are at work. Instrumentation technology involves ergonomic engineers and other engineers and designers. Instrumentation technology can be characterized in one sentence, viz. the science of methods of learning and teaching, respectively the science of designing methods (in its widest sense) of (in particular) learning.


Figure 2.1. Place of computer simulation as educational software within instrumentation technology and educational science. The area of interest (shaded) is computer simulation. Within this area are to be distinguished: simulation CAL, simulators for training and non-educational computer simulations.

Instrumentation technology has a great influence on the didactic environment of each individual. This aspect of learning in a didactic environment requires most of the computer in learning but not in teaching processes. Because for auditive or verbal instruction the teacher remains most important. There the computer appears not to be any better than the teacher. In a didactic environment, however, the computer is able to do something really unique, namely calculate things like models, and associate. Computer simulation programs are considered educational tools. Such computer simulation programs together with the computer are pre-eminently products of instrumentation technology and applied educational science. The reader can best form an idea of the use and the possibilities of computer simulation programs by realizing how experimental settings are used in labs. So this book will concentrate on the use of computer simulation programs as an educational tool in situations which can be compared to practical labs and in which the method of problem guided (discovery) learning is attempted.


2.2 Hardware

The use of the computer as an apparatus in learning demands a great deal of the computer itself. It is of course not so much the computer which is the educational tool, but the program which is used as an educational tool. Instrumentation technology pays much attention to the quality of programs. The quality of an educational program, in particular interactive animation programs, is determined by the performance of the apparatus used. The apparatus itself is the basis for a good educational product. A good didactic apparatus is a very important condition for good educational software.


Figure 2.2a. The hardware of the compact, portable, educational environment for simulation: A small Macintosh computer; the keyboard is redundant. This is the 'learning environment' for MacTHESIS software (version 3.1, 1986)


Figure 2.2b. An photo of the hardware of the compact, portable, educational environment for simulation.

The term instrumentation in educational science does not apply to the instrument only, but also to the software. For the apparatus as well as the software the facility of operation and design of the educational setting (in literature indicated by terms as 'human factors' and 'users interface') are not a case of merely well-applied techniques or ergonomics, but because should be possible to learn instrumentation technology with it.
The interaction of the program with the environment, i.e. educational setting, is important for an applied education teacher. Instrumentation for education is didactically justifiable when a good educational environment has been designed, realised, and evaluated.
In computer simulation it is often important for a designer to get rid of the computer itself (and the keyboard) in order to make an instrument which is as user friendly as possible. After all, a keyboard is intended for the programmer in the first place. The question here is: Is the keyboard really necessary for the user in certain kinds of educational software?

In many cases it appears that for didactic programs those hardware sets are used which are also used in developing software. A keyboard is however an obstacle in some applications. Being able to find the right key is for many pupils not easy at all. Any key but the right one then functions as an interfering element. A keyboard is not at all necessary, for many multimedia applications due to the invention of other input techniques (e.g. Smalltalk and the Macintosh with windows and the mouse). A keyboard is not absolutely necessary in a Macintosh program for most applications. If a keyboard should be necessary, it is possible to put one on the screen with the program and the mouse can be used to type letters. The program then has to be designed in such a way that the word, typed in this way, can indeed be processed by the program. It is to be expected that in Hypermedia applications or interactive video a keyboard will not be necessary any more in the near future.

2.3 Software

Computer simulation programs which are used in education, in courses or other forms of training, have to be counted among the didactic (or educational) software and are always interactive.

Interactive software

In general interactive educational software can be made in three ways. The advantages and disadvantages of making software with one of these methods will not be discussed within the scope of this book. These three methods in making (and designing) educational software - and in particular multimedia programs - are:
The last is especially important for computer simulation. In computer simulation software we assume that what is valid for ordinary software is also valid for computer simulation software: viz. that programming in a high level computer language, like Pascal, will give the designer the utmost freedom. Consequentially, this method will be discussed in this book. Further down there will be some remarks on making modern event-driven software with Pascal. In developing multimedia using a high level computer language, the experiences of others in the field are used. This means that for software, and certainly interactive software for the development of multimedia use, has to be made of software 'libraries' with procedures which other informatics specialists have developed. These 'procedure libraries' are either supplied by the manufacturer of the hardware or are bought from software agencies or have to be designed and manufactured for special ends (like for computer simulation software).

In most personal computers there is a limitation to the size of a program. To execute or run large programs all sorts of tricks have to be applied that are taken to be methods and techniques for the development of software. A popular method is: texts, numeric and graphic data in files are put on floppy disk and the data are called upon in the program by procedures. In figure 2.3, but in more details in chapter 3, you can see this concept of separation between (static) information in files, the tools in libraries and the (dynamic) behaviour of a program on the sreen. Data are only then taken into the working memory the moment this is necessary and can be thrown out when other things have to be taken in. A courseware designer has to be able to find the right balance between taking data into the program itself and making data bases.

Educational software

When is software educational or what makes a program an educational program? Educational software is an important part inside the educational instrumentation technology but on the other hand there are all sorts of similarities with informatics. We may, however, say that informatics engineers in general pay little attention to the demands of education. Writing a good textbook involves more than merely manufacturing printed matter, in the same way an educational program is primarily something that has to fulfil an educational task in learning or teaching. At least two sorts of programs can be distinguished viz.: In the first case there is practically always a specific situation in which no standard interface can be used. The designer then has to pay special attention to the lay-out of the presentations, etc. in short multimedia techniques. Namely, for each user it is the first, and usually also the last time, that he or she sees the program. In the second case ordinary commercially-made software (like editors, compilers, calculators, etc.) can generally be used in an educational situation. Such programs have been developed in an entirely different way. So multimedia always has a disadvantage in that it is usually used by someone only once (and it has to be immediately clear to the user how to use it) this in contrast with application programs (like word processor programs), which are used time and again.

2.4 CAL techniques

In order to be able to run or watch programs there has to be an adequate user-interface. There is for the designer a whole series of known and lesser known methods and techniques. Here we call them CAL techniques. By CAL techniques are understood those program techniques, methods or instruments to which a designer needs to adapt the software for use in education. In doing this the aim is to ensure that a program has a possibility for interaction, and is didactically efficient. On the one hand there are all sorts of output techniques like graphs (pictures), animations, screen photos or a human voice for presentation, and on the other hand for acceptation various input techniques like the mouse, joy-stick, microphone, touch-screen, light-pen. Beside that, a program has to be able to make use of (communicate with) data banks, models and expert systems, if necessary.


Figure 2.3a. A program is only educational software when much attention has been paid to 'presentation' (output), 'acceptation' (input) and 'communication' techniques. Communication is possible with models, rule bases or sometimes files with complex data.

Figure 2.3b. A computer simulation program communicates with a mathematical model or something else.

In this book the following kinds of CAL techniques are distinguished:


In figure 2.4 this division is schematically represented in kinds of techniques.

Presentation and acceptation techniques

A monitor is generally used for software to transmit text information to a user and a keyboard to get information from the user. Then there is also communication through a database, which happens as a matter of course because every computer is usually equipped with a keyboard and a monitor for text.


Figure 2.4 Presentation techniques, acceptation techniques and communication techniques (special media as well as special software procedures) as they occur in educational software.

But nowadays there are many alternatives for man-machine interaction or user-interface beside monitor and keyboard. For people with a visual or auditive disposition an animation representation form or sound presentation through headphones, for example, can be chosen as an alternative for text presentation on a screen. It is well-known that many people do not read screen texts carefully, especially when they are long pieces of text on a bad screen. CAL or CBT often gives the impression of being a 'badly-represented book' and when the turning of a 'page' also happens quite clumsily the pupil will easily get lost in the program. In certain programmed instructions or some tutorials made with author languages or author systems turning the 'page' is too complicated. Learning requires being able to put material side by side in order to compare things. It is certainly a problem when in a learning cycle previously presented material is hard to retrieve. Such impractical programs are eventually not used anymore for the disadvantages then outweigh the advantages. Microcomputer technology of today (e.g. windows and mouse steering) has made multimedia much more attractive. It is true that these innovations are realised slowly, but the expenses and effort required for the development of a good design also decrease. All sorts of combinations of presentation, acceptation and communication techniques which have been impossible until recently, like overlapping windows, can now be applied and are better to handle for the designer and programmer (once you have good software libraries).

Today a trend can be seen in multimedia into the direction of interactive video. This is normal video, as an educational tool, coupled with a built-in-microcomputer with for example a mouse as an operational device. With this the pupil has got an interactive educational tool. Passivity (in the sense of not being able to intervene) is here replaced by activity. This formerly sequential events with a definite beginning and end, has thus become visually just as attractive a medium as video but interactive. And that together with the possibility of the spoken word, will appear to be superior to the courseware presented in the old-fashioned way. Beside the computer is completely pushed into the background, at least from the pupil's point of view which can be judged as a positive change.

For the designer of multimedia, interactive video remains a form of multimedia, but for the pupil it is a much more normal educational tool. Of course software still plays an important role in interactive video, if not decisive, but it is clear that the representation techniques are swiftly developing into the direction of visualization and the spoken word. In this way multimedia will be easier to understand and to operate. What is more important is that it will be more readily accepted.

The designer of multimedia has, with regard to indication media, the choice between using a touch screen, a light pen, a joy-stick, or a microphone which can recognize words like 'one', 'two', 'three', 'yes', 'no’, etc. In a real multimedia program one indicator has to be consistently applied.

The choice of presentation and acceptation techniques has to be coherent and clear. This choice depends among others on the goals of the multimedia program and on the ergonomic principles used by the designer. To mention two extremes: a multimedia program can be equipped with a screen and a keyboard, but also with just a microphone and headphones, without a keyboard and in the most extreme case even without a screen. As an example of a third variation we also mention a joy-stick-guided educational animation for a titration proof on a color monitor. The use of vividly visualized educational software with computer animation techniques will in the near future be based on a.o. video pictures in the background and look like interactive video, just like interactive games.

Communication techniques

The communication of a program with a database can be active or passive. By active is meant that information in a database can enhance a program. Reading a database with texts or graphic databases gives an information-flow from database to program at which no more takes place than a mere transformation of data into a picture on a presentation medium (passive). When, however, a database contains a code for a language then much more can happen in the program. The data actively contribute to the further course of the program (active).

A database with an interpreter is in fact a good example. A language like LOGO, Pilot, or TenCore is in fact written like a normal ASCII database. The interpreters of these languages do nothing but read the instructions and texts from that database and execute them immediately. This is completely in contrast with languages which have to be translated first. The program (the interpreter) then communicates in a more or less active way with a database which contains the written program. The interpreter and database as a whole are nevertheless called a (multimedia) program. It is in any case clear that text contents are in a database and not in the program itself.

A database can vary from a set of records (rules) in a normal file (on a floppy in a local PC) to an intricate data bank at a great distance (e.g. Viewdata). There is no principal difference between the names 'file' or 'data base', they are used indifferently! But technically they can completely different and very complex. The advantage of using databases, in particular those containing the contents of the lesson and which can be operated beside the actual program, is that such databases with ordinary edit-programs can be changed without having to change the multimedia program itself. The reverse is true; a change in the program can be separated from a substantial change stored in the databases. It can also be considered as an advantage that a program can have many 'contents' when the database is changed. A multimedia program can, for example, look into and use the most recent data about a subject from a centrally located disk unit at any moment of time.

2.5 Designing environment for simulation and animation programs.

Today a whole series of application programs (tools) which are easy to use, or as we call them designer-tools, are at the everybody's disposal to design, change and maintain educational software for every type of computer or operating system. When on top of that the processing is in Pascal, as discussed in this book, we call this a Pascal software environment or Pascal designing environment.
Today there is, beside all sorts of ordinary text-editors or word-processors, a whole series of other editors as tools for designing, namely:
Thus there are complete micro-CAD/CAM-systems for graphic editing like on the Macintosh (SuperPaint, PixelPaint, Photoshop, Canvas, Painter and others), Amiga and Atari 1040. On many computers, notably on the 68000-computers, there are animation-editors (MacroMind Director), music-editors (SoundWave, Concertware) and even program-designing-editors (Blues). The characteristic of all these 'tools' is that a physically existing product is produced like a database, a bitmap or series of bitmaps. A Macintosh program, made with a so-called resource-file (system element database) is even revisable afterwards with a so called resource-editor (ResEdit), without having the disposal of the source code of the program.

It is possible to intervene in the executable version of the program and particularly to bring about textual changes (e.g. translation of the menus). MacroMind Director and ResEdit are products to use on Apple Macintosh. A module-editor is found in the dutch author-system Taiga. The systems Hypercard or SuperCard are advanced integrated systems with a lot of editors. The data is an integrated part of the structure. The program and data are combined in one so-called stack or project. The products Course of Action or AuthorWare Prof. are the most important author-systems for multimedia nowadays. In a multimedia program special procedures have to be included in order to be able to transpose these separate products (all sorts of databases) into, for example, a picture on


Figure 2.5. The complete designing environment for computer simulation software with all the designing tools (text-editor, graphics editor, libraries, etc.). The computer simulation program can make use of various kinds of databases (text, graphic database, etc.). The teacher can, if necessary make changes in the data of the various databases (the static information). The didactic environment of this designing and changing environment is completely masked from the pupil.

the screen or a piece of music in a loudspeaker or a headphone. An author-system is in essence an advanced integration of such tools. But it has the disadvantage that the designer can not get at it anymore, for such a system is in one piece. An author-system itself is in fact another application program which can be used to design quickly tutorial multimedia parts and fit them into another program. Yet, the databases manufactured with such an author-system have to remain accessible in order to be able to read them again.
A well-equipped Pascal programming set with a design-system and a series of good libraries and designing-tools is best for the design of a computer simulation program. The absolute freedom of programming in a high level computer language is coupled with everything that an author-system and an author-language also contains.
This is the essence of this book and the method to develop computer simulation software

2.6 Universal design systems for building computer simulation programs

At the University of Twente, Faculty of Educational Science and Technology, a universal design system for educational computer simulation programs was developed during the period of 1984 to 1989. The system can design stand-alone applications or modules for implementation in tutorial or instruction authoring systems like HyperCard systems. Trained courseware designers can make any computer simulation program with this design system. It has now been demonstrated that this system is an universal simulation tool in the fields of physics, biology, medical science, in economics and technical installations. The system is called MacTHESIS for Macintosh and THESIS for MS.DOS computers. The educational programs to be made with it, are based on a special kind of philosophy of instrumentation technology - the MacTHESIS philosophy - and are characterized by advanced visualization, a small number of windows and simple operation.

The name THESIS comes from 'hypothesis' and is used in the meaning of 'supposition of reality', a name well suited for a computer simulation system. THESIS also means 'Technische Hogeschool Twente Educational Simulation System' in which 'Technische Hogeschool Twente' is the former name for this university.

There are more computer simulation systems, based on the MacTHESIS philosophy. The complete list of the names of the computer simulation systems of the THESIS family is:

All systems allowed the same structured mathematical models. When a program is designed on one system, the designer can implement the well-structured model simply in an other member of the THESIS family in a relative very short time. See figure 2.13. The MacThesis system is designed as an universal simulation system. It is specifically suited for handling extensive models and for integrating with simple instruction design systems like HyperCard, SuperCard and AuthorWare Professional.


2.7 The computer simulation system MacTHESIS

The universal design system MacTHESIS works on a Macintosh II computer (see figure 3.5). The 'designing environment' exists from editors, compiler, libraries and tools.
The products made with MacTHESIS are easily manageable educational tools on a floppy disk which can be stored (hardware included) after use, simply by taking out the plug, when the small Macintosh Classic or SE computer is used. By restarting the computer the model in the program in the 'learning environment' is restarted.
The floppy with the program and the operating system don't leave this computer system in this case. The designing environment and the learning environment aren't on the same computer. This compact, turn-key, resettable learning environment, include the floppy inside, and the paper materials outside the computer, is shown in figure 2.6.

The simulation programs link up completely with the 'desk top' philosophy of Apple Company and the pages (windows), page size and place of the pages can be manipulated on the screen by the mouse. Certain interesting 'dynamic' processes take place on the screen. One can intervene in these dynamic processes by clicking with the mouse in special, so-called 'in-click regions' or else with the help of pull-down menus. The products made with MacTHESIS are manageable educational tools which can be stored after use.

Characteristics

The main characteristics of the computer simulation programs situated in the learning environment, and based on our philosophy of computer simulation programs in education, and built with MacTHESIS, are:

Figure 2.6. The complete 'learning environment' of a computer simulation program made with MacTHESIS (version 4.5, 1994): an learning environment with a simulation program, an instruction program, a scrapbook, a parallel 'full screen desktop video feedback system' based on video fragments from a VLP in an external VLP drive (ODB project of Verhagen, Zwart and Min, University of Twente, 1994).



See also chapter 3: the MacTHESIS philosophy and parallelism.

For some kinds of education the computer simulation system THESIS (VAX version) or the RLCS system was too expensive because a second monitor was needed. By the appearance of the 'windowing' and 'mouse' techniques it appears possible to keep the two essential processes which occur in simulation physically apart so that the offered information can be studied separately. The computer simulation programs, developed by the University of Twente, have been evaluated in the course of the years: from programs which run on two screens (in the RLCS system) to programs, built with MacTHESIS for compact 'multi windowing' computer animation programs in color, which can be embedded into a CAL tutorial or instruction program of HyperCard cards or a course built with Course of Action / AuthorWare Professional.

There are a few conspicuous characteristics, some possibilities and advantages of computer simulation programs which have been made so far with MacTHESIS:
Thus 'MacTHESIS software', implemented on a Macintosch 512k, Mac plus, Mac SE (all with MacTHESIS version 3.1) or Macintosh II mostly has the character of a 'monolithic', 'turn-key' and 'student proof' educational tool. The Macintosh II version (with MacTHESIS version 4.5), isn't 'monolithic'. (See figure 2.6.)

With the MacTHESIS family one can distinguish a lot of environments. The main kinds of environments are:
Other environments names in this case are: didactic environment , instruction environment, integrated learning environments, Pascal environment , programming environment, etc.

Computer simulation programs made by MacTHESIS are supplied on a separate floppy. A floppy with the program can remain permanently in the computer. The computers do not have a keyboard. So that this type of simulation environment is even more 'dedicated' and not 'general purpose'.

Each computer simulation program has a manual and a workbook with the assignments and descriptions of the case studies which are considered inevitable for the use in education. However, the whole lesson has to be very convenient and practical. That is why this so-called 'coaching material' has remained out of the computer so far, to be able to offer the course material 'in a parallel way' and not as in classical tutorial courseware in a 'sequential' way. Preferably the worksheets with the case studies are supplied on loose sheets of paper. The loose sheets of paper and the sheets on the screen make a very good educational environment. This has been shown several times by staff members and graduates with different programs. Later on in this chapter about the advantages of the 'multifinder' this concept of parallel sheets and windows will be discussed.

The sliding windows can be interpreted as 'pages' of a book of two to five pages. Such a computer simulation program is indeed like leafing through a book. In the computer simulation program one and the same process happens, but it is represented in two or more different ways on the various pages. MacTHESIS software represent the dynamical behaviour of a model with (dynamical) graphics, animations and even by texts, in addition to the statical representation in a book or in the student manual.

MacTHESIS software has the same possibilities as the programs build with the RLCS system from the University of Limburg (Min, 1982), like 'start-stop', 'changing', 'inspecting', 'restarting', 'cases' and 'quit'. These options are implemented in the menu-bar of the software. There is an option to order the windows in three different ways on the screen, reduction of all pages included. In this last option it is possible to get all windows in 'full size', 'reduced' and 'moved', on the screen together.

Building programs

A computer simulation program can be made with MacTHESIS by fitting in the MacTHESIS shell information about the chosen mathematical model at twenty different places. After the 'compilation' of the mathematical model, in particular and subsequently 'linking' with the special procedures library, SIMLIB (and the Macintosh toolbox), the specific computer simulation program comes about and 'generates' programs for the Macintosh 512, plus, SE. classic or the Macintosh II serie. So MacTHESIS is a 'program


Figure 2.7. Starting with the development of a computer simulation program with MacTHESIS is collecting all parameters and variables of the model in a 'black box'. (first step, the 'inventarisation phase')


generator' for computer simulation programs. The programming environment which is used by MacTHESIS is the Macintosh Programming Workshop: MPW. These environment includes an editor, a compiler, a linker an some libraries.

The editors used in the designing environment are MacPaint or SuperPaint (for black and white visualisations) and/or PixelPaint (for color visualisations), both for the 'statical' graphics behind the pages. The figures and graphics made by these editors give the typical, characteristic, visual user interface. The 'resource editor' ResEdit is used for editing graphics and text when the computer simulation program is finished. ResEdit and the other editors are also important for the teacher at school to change something of the program, text or graphics in his own way.

The designer has the liberty to choose from a library with a great number of standard representation forms. Furthermore it is possible to create a lot of animation objects and display objects (like counters, etc.) in the first window moved by values of variables of the underlying model. Although an animation is strongly bound to the model, MacTHESIS supports animation as a standard technique. The first window of each MacTHESIS program is called the 'animation-' or 'input-' window. Realisation of an animation in the 'animation window' with 4 to 6 objects and 2 to 4 display objects is not a


Figure 2.8. The second step by designing a computer simulation program with MacTHESIS is to visualise the mathematical model and to collect the interventions and the most important output variables. ('visualisation phase') In this visualized mathematical model is seen 3 in click regions (or hot spots; black dots) and 3 output variables with decimal counters (open dots).


great problem. MacTHESIS also enables the student to make a static background (MacPaint documents) and to program animation objects (incl. trajects, scaling, etc.) with it. The 'animation window' is also in use as an 'input window'. The name 'input window' is based on the phenomenon that one can intervene in the visualized mathematical model by means of the 'in-click regions'.

The last thing that has to be done when building a computer simulation program is changing model-bound texts and declaring parameter values, cut the old model stuff from the MacTHESIS shell and paste the new model stuff into the marked places in the MacTHESIS shell.

The designing environment consists of a hard disc with all the tools, editors, libraries and the MacTHESIS shell: the source and the resource file (see figure 2.5). There is also a printer and, if possible, an extra Macintosh computer, to make MacPaint documents in order to look up coordinates and to test the computer simulation program at once during the designing phase.

The learning environment is a minimally equipped Macintosh, turn-key, 512k computer (because a Macintosh 512k is cheap), no keyboard, only a mouse and paper work sheets and student material. See figure 2.9


Figure 2.9. The third step in building a computer simulation program with MacTHESIS is to collect all attributes which are necessary for implementing a model in MacTHESIS. ('realisation phase')


There is one extended Macintosh at the school or in the classroom for the teacher with an extra floppy unit and a keyboard. The teacher needs a keyboard for editing courseware materials. This environment for the teacher is the so-called 'editing environment' of the MacTHESIS system. Here the teacher can fit his or here own ideas into the programs. He or she has the disposal of a graphic editor, a resource editor and some other applications and help programs. All the 'static material' can be changed with it. Texts can be changed, pictures can be readjusted but the executable version of the computer simulation program can also be changed (texts, window coordinates, etc.). These are important matters for a school or a teacher.

The source and resource remain with the designer perfect and safe. These facilities are not or hardly available in other than 68000 computers (for example MS-DOS computers). The separation between source code and executable program is perfect. Of course the teachers can also make their own learning material for their students beside the computer simulation program.

Products (prototypes built with the MacTHESIS system)

With MacTHESIS more then fifteen programs and 30 different kinds of prototypes have already been designed. The designing time varied from a few hours to one day, one week or six months, depending on whether the model had few or many liberty degrees. By that we mean that everything can be solved with standard facilities, or that there are many animation activities or that selecting an intricate case takes much time. Some examples of computer simulation programs can be seen in the following table and paragraphs. The table below shows the history of the computer simulation systems mentioned here and some computer simulation programs.

A table with our computer simulation systems and their most important output (executable software and/or applets)
parallel window systems:non parallel window systems:
RLCS system (1982)
* CARDIO
* FLUIDS
THTCS system (1985)
* CASCADE
* LEMMINGEN
* CARDIO AppleTHESIS (1986)
* AORTA * AORTA
* FARMA * ECOLOGY
THESIS (Vax version) (1985) MS.THESIS (1987)
* CARDIO * REEKSEN
* CHEMISTRY * AORTA
MacTHESIS (1986-1992)THESIS (MS-DOS version) (1988)
* CASCADE * SUN HEATER
* SUN HEATER * FISH POND
* FLUIDS* PERCH
* ECONOMY* FLUIDS
* CELLS* CHEMIE
* FISH POND* CARDIO
* BRINE-PURIFICATION* PERCH
* TRANSISTOR
* CARDIO
* COAGULATION
* ENZYME
* SUCROS (1994)
* STRATEGIC (1995)
MacTHESIS (HyperCard version)
* CELLS
SuperTHESIS (1991) HyperTHESIS (1989-1995)
* ENZYM * AORTA
* COAGULATION * AORTA (QuickTime version)
JavaTHESIS (1997-1999) JavaTHESIS (1997-1999)
* CARDIO (1999) * CARDIO (1998)
* AORTA (1999)* AORTA (1998)
* TRANSISTOR (1999)
* CONTROL SYSTEM (1999)
* BOILER (1999)
* LEMMINGEN (1999)
* LEARNING

MacTHESIS programs also run cheaply in black and white on Atari 1040 ST (with MacBongo or Aledin), in Executor (1995) on 486 computers and more expensively in color on Macintosh II computers. Presently it is being examined how MacTHESIS software can be furnished with a window in which a video instruction film can be shown. The video fragments are selected by the state of the model and present in an output window of MacTHESIS software. Now the principles of interactive, model- controlled 'desk top' video can be incorporated in the computer simulation learning environment of MacTHESIS software. See for this idea the computer simulation program COAGULATION / STREMMEN in figure 3.17.



2.8 Other THESIS systems

THESIS (MS-DOS version)

In the period 1985-1989 Van Schaick Zillesen of the University of Twente developed the computer simulation system THESIS (MS-DOS version) for computer simulation programs on MS-DOS computers. The main characteristics of the computers are: MS-DOS version 3.1 or higher, CGA card 640x200 pixels, Written in TurboPascal, QWERTY keyboard and without a mouse.

Just like the programs generated by MacTHESIS, the programs generated by THESIS are usually provided on a turn-key floppy-disc. In the programs generated by THESIS two levels are present: the main level and the simulation level. The menu-bar of the main level enables the students to select one of the options, as 'explain', 'end' and 'case'. Students can control the programs by means of a menu-bar. The functions are 'time', 'values', 'recover', 'change' and 'screen'. Compared to MacTHESIS the structure is less transparent to a student. Programs built with MacTHESIS have, visual 'parallel information output' as we call it and built with THESIS: 'sequential information output'. A status line has been developed in order to overcome the problem of getting lost in the program. It informs the student about his location in the program.


Figure x. The hardware of the RLCS-system.



Figure x. The hardware of the first THESIS-system.



Figure x. The hardware of the MacTHESIS sytem (version 3.1...) (19..).



Figure x. The hardware of the MacTHESIS sytem ( 19...) (a special version of version 5... with 3 screens).

MacTHESIS (HyperCard version)

There is a MacTHESIS system that looks like cards as used in HyperCard: MacTHESIS (HyperCard version). This version of MacTHESIS is used when simulation programs have to be implemented as modules in HyperCard stacks or Couse of Action courseware.

HyperTHESIS

There is also a computer simulation system built in HyperTalk Script in HyperCard:


Fig 2.10 AORTA, a computer simulation program build with HyperTHESIS. This one-window program generates QuickTime video messages in a parallel (movable) window.

HyperTHESIS. This version of THESIS is developed for testing the performance of HyperCard and Macintosh II computers. It is a one-window system with in-click regions, in which the buttons have different functions such as: 'start-stop', '(re)start', 'inspect', 'change' and 'quit'. It is a shell system in an object oriented programming environment. The model and the model data can be changed just as in the other computer simulation systems described earlier.

SuperTHESIS

Recently an 'event-driven', multi-windowing computer simulation system without pull-down menu's, named SuperTHESIS, has been developed. The system has the same characteristics as other systems of the THESIS family. The system couples the possibilities of HyperCard together with the multi-windowing possibilities of SuperCard. It is a multi-windowing system with 'panels', in which the buttons have different functions, such as: 'start-stop', '(re)start', 'inspect', 'change' and 'quit'. It is also a 'shell system'. The system is written in HyperTalk/SuperTalk (script) and it is an interesting multi-windowing system for both simulation and tutorial courseware. The model and the model data can be changed in the same way as in the other computer simulation systems of the THESIS family. SuperCard software is an interpreter system. Small models can be written in the script language. When the calculation time for the model is too bad, it is possible to program an external command that executes the (compiled) mathematical model. This version of THESIS is developed for testing the performance of SuperCard on Macintosh II computers.


Fig 2.11 PASTEURISEREN, a computer simulation program with 5 parallel windows build with SuperTHESIS.

2.9 Imbedding of MacTHESIS products into an instruction environment

At the University of Twente it is now being considered whether paper course materials can be substituted by HyperCard stacks, since they can be made with the HyperCard system by Apple since 1987. These HyperCard products might be an ideal type of tutorial courseware. In these stacks the MacTHESIS software can be 'built in' and used without seams.

HyperCard stacks can then function as a overall tutorial course program and used as an introduction to one or more of the 'implemented' computer simulation programs. Also it is constructive if after working with the bare simulation program the student can easily be tested in an other part of the HyperCard courseware. The research is aimed at designing and creating the most suited learning environment for regular as well as professional education.

One of the most important hypotheses of the THESIS simulation research project which are being tested by Min and others, is whether MacTHESIS is indeed suited as a design system to remodel all sorts of models into complete educational computer simulation packets. A second hypothesis which is being tested by Van Schaick Zillesen (1990) is: is parallel represented processes more effective than sequentially represented processes. (Van Schaick Zillesen, 1990). Finally research is being done into the hypothesis that a complete 'tutorial shell' with HyperCard, around a simulation, functions better than accompanying paper material, based on the thesis:

Model + MacTHESIS + HyperCard = a complete educational multimedia packet

For that purpose a few simple prototypes of HyperCard stacks have been written with HyperCard and MacTHESIS. The results are promising such as the project BRINE PURIFICATION, described in chapter 13, at a large chemical plant in the east of the Netherlands.

Figure 2.12. Implementation of a computer simulation module built with MacTHESIS, implemented in HyperCard stacks ('implementation phase'; parallel using method). The hypothesis is: Model + MacTHESIS + HyperCard = an interactive, dynamic educational tool in color. Left: the sequential method; right: the parallel method.

Figure 2.7 up to figure 2.12 gives the 4 important 'stages' or 'phases' a designer gets: from making an 'inventory' of the model to 'implementation' in a tutorial HyperCard stack. The 4 phases in designing an total computer simulation program packet are:


The 'inventory' phase (figure 2.7) is the first phase in designing an computer simulation program. The black box representation way of the model gives an important overview for discussion between the designer and teachers to find out what are the most important variables and parameters for educational use. Figure 2.8 gives a schematic representation of the 'visualization' of a model. Figure 2.9 gives the overall plan of the computer simulation program with all its windows and sub windows. In the MacTHESIS system the variables of a mathematical model can be shown in several standard ways: varying from decimal counters to graphic representation forms and animated representation forms. The procedures library of MacTHESIS, SIMLIB includes special procedures for that in order to be able to instrumentate these representation methods. Figure 2.12 shows the total courseware packet of the tutorial HyperCard stack and the simulation module together.

Model transformation

For researchers who, after years of searching, wants to re-form their 'own' model - not for research - but specially in an educational computer simulation program it is of importance to know how their models have to be implemented in these family of THESIS systems. Models from research mostly always are proofed and have been determined completely and implemented in computer simulation languages- or 'modelling-systems' -mostly interpreters -like CSMP, TUTSIM, STELLA, LabView or SimTek/Mosaikk. It cost not much time to translate such models to these computer simulation systems. All systems of the THESIS family use the same structured mathematical models. So, inside the THESIS family the designer can also simply implement the model in an other THESIS system. A mathematical model, if structured as described in this book, can be switched (by cutting) from one system and implemented (by pasting) into another THESIS system in a very short time.

2.10 Results

From the THESIS project two computer simulation systems have emerged: MacTHESIS and THESIS (version MS-DOS). The first system works with the method of a 'parallel information presentation'. The second is more a 'serial' system and is called: 'sequential information presentation'. Both systems are in use by a lot of designers for building a wide scale of different computer simulation programs.

With the MacTHESIS designing system computer simulation programs can be made with the characteristics mentioned above. With MacTHESIS it has become possible to remodel a mathematical model into a complete educational tool.
In figures 1.3 and 1.6 (chapter 1) and a lot of figures in chapter 5 to 10, one can see some examples of MacTHESIS software. At the top of the screen the pull-down menus are situated in the menu-bar to be able to operate the program. Thus the assignments and problem cases can be chosen, or the model can be started or stopped. In the pull-down menus there is an option to enlarge and reduce the 'pages' or to put them on the screen in a standard way. On the first page, with the visual model, animation objects can be included in order to give the student a 'visual feedback'.

By now over ten such programs, have been realised like


MacTHESIS software can be fit without any difficulty with HyperCard stacks on a parallel way - in two processes - or on a sequential way. Figure 2.12 shows the parallel using method. Further results of this typical educational instrumentation technological research and development project are still being collected and worked out including evaluation results. There is, among other things an observation study from 1988 in the laboratory of the Faculty of Educational Science and Technology with about ten representative testees. The video tapes with the results have been processed.


2.11 Concluding remarks

The prototypes of MacTHESIS software are continually developed and evaluated. The prototypes which combine MacTHESIS and HyperCard are being developed. Staff members of the Faculty of Educational Science and Technology and some groups of 3rd and 4th year students are developing more extensive stacks. At the moment one can clearly see the resemblance of the character of a 'page' from MacTHESIS software to a 'card' from a HyperCard stack. The cards as well as the pages can be moved across the screen. However the pages of MacTHESIS software are interactive, dynamic and in color. Up to now this has not been possible in HyperCard. In SuperCard and SuperTHESIS it isn't a problem. HyperCard and SuperCard have insufficient possibilities and too few 'performance' in some cases, but the system of external commands on compiled Pascal procedures is a good and acceptable solution.

Note:
Parts of this chapter were first published in Dutch in: Min 1987; Academic Service Schoonhoven and later in English in: Modellbildungssysteme, Konzepte und Realisierungen; J. Wedekind & W. Walser (eds.), COMET (1992) 3-89418-709-9.