PROGRAM ASPECTS

Chapter 14. Some Special Simulation and Animation Programs

The figures - as referenced in the text - are not ready yet. See the textbook itself. (R. Min, Academic Book Center, De Lier, 1995)

This chapter discusses:

14.1 Computer simulation program PHYSICIAN / ARTS (small expert system)

It is generally known that expert systems and artificial intelligence seem to have become apt aids for researchers and developers. We try to prove that these systems can also become interesting for educational purposes. For an expert system can be adapted for use in education. A pupil , student or trainee might like to consult 'experts' (as a 'tutor') in his or her study, and use CAI programs which can simulate an expert. Such CAI software, containing an expert system is called an 'intelligent CAI' (ICAI). However, expert systems in CAI or CAL context have not yet been realized, but this will undoubtedly be developed in the near future. For the discussion it is important to discern at least three kinds of expert systems:

1. 'Logical decision tree' systems, based on decision rules (if-then-else-like rules) which are similar to methods for determination of a plant with the help of a flora.
2. Systems which use calculation of probability with the help of the method by Bayes by which, for example, the probability of a symptom of an illness is turned into a probability of that syndrome when such a symptom is found.
3. Systems which make use of special languages like Prolog, Smalltalk and LISP.

In chapter 1 the basic idea is described which underlying the second method described by a.o. Lusted (1968) and De Dombal (1972), using the method by Bayes. This is done on the basis of an example from the practice of a medical specialist with four syndromes in relation to seven symptoms. A non-medical subject could also have been chosen, but a medical example is perhaps more appealing, because it is a question of a diagnosis in the most ordinary sense of the word. With this expert system a diagnosis can be given (automatized) when a student answers the following questions:

The computer program PHYSICIAN / ARTS answers:

The most probable diagnosis is Asthma Bronchial with a probability of 0.575.

The computer program containing the expert system has been developed by the Universiteit Twente, and is called PHYSICIAN / ARTS. There are three different versions. The first version was realized on an Apple II microcomputer and is used in a lab for the third year subject 'CAL-technics' for students of the University of Twente. The second version was developed on a Macintosh computer of Apple in Macintosh Pascal and it only uses texts (see figure 14.1). The third version was also developed on Macintosh and it has the special feature that the calculated chances are always graphically represented after answering a question. This provides good visual support during diagnosing. This option is also important for 'gauging' the expert system. It is not yet quite clear how expert systems will acquire a place in education. The possibilities for the training of medical students and laboratory workers are enormous. For non-medical education there are also plenty of possibilities. Think of a training where diagnosing has to be learned, like analyzing break downs in cars or computers: so in technical education; in determination as with a flora or fauna in microbiology: at laboratory colleges; in classification and making automatic divisions: in financial, economic or judicial fields; in pattern recognition; in geology, meteorology, etc.


Figure 14.1a ARTS, the smallest expert system in Holland, based on Bayes statistics (Demonstration version, 1999; with animation).


Figure 14.1b ARTS, student version, 2002; with video and in Dutch.

At the University of Twente not only a medical example has been developed of an expert system based on this method, but also one from biochemistry that can differentiate between acute hepatitis, jaundice caused by a blockade in the bile, cirrhosis and liver metastasis, and an example from sociology that can differentiate between various political convictions.

14.2 Computer simulation program HISTORY TAKING / ANAMNESE (medical interview training program)

The computer simulation program HISTORY TAKING / ANAMNESE is especially designed by the University of Utrecht to give students the opportunity to train themselves in taking the anamnesis (the interview between doctor and patient) of any given patient with a certain clinical picture. The program has five simulation patient cases. Before the student takes an anamnesis of a real patient, the student is given a chance to learn to survey the anamnesis for any given clinical picture. With this program it is possible to simulate in an easy (and cheap) way a doctor-patient environment. If a certain computer simulation patient is not relevant or has been dealt with, then another patient can be chosen immediately. The student is able to use the directly accessible patient data bank of the anamnesis training program, which is simpler than with an ordinary simulation patient. Beside a student can use this program the moment he or she is ready for it.

The program HISTORY TAKING / ANAMNESE introduces the student to the classical construction of the anamnesis, in which it is precluded that questions are asked in accordance with a choice hypothesis.
Other ways of taking an anamnesis are particularly not excluded while the program is used. In the program the emphasis is not on problem solving but on getting a complete survey of the anamnesis. The program is divided into and based on principles according to the textbook of 'Anamnese en der fysische diagnostiek' (Anamnesis, history taking and physical diagnostics) by Formijne and Mandema (1976). According to this method it is important that the student has to go through all the tracts ('chapters') of the anamnesis before he or she formulates (a) provisional diagnosis(diagnoses). The student has to pay attention to the complaint with which the patient has come. Subsequently the patient is questioned extensively (from top to toe).
With this program there is a system of messages that offers instruction at certain unexpected moments, accoording to Boolean logic. The presentation of this kind of messages depends on the question, the patient  and his or her answers. The program also has a system of operations for self-testing which are shown to the student at seemingly random moments and which have to be answered before proceeding. The results of it come back at the end of a program series in the evaluation of a session.
The computer simulation program HISTORY TAKING / ANAMNESE has originally been developed in Utrecht, at the Rijksuniversiteit Utrecht (Min, 1978; Min and Epraïm, 1979) at the Instituut voor Nucleaire Geneeskunde (Institute for Nuclear Medicine) in cooperation with the Kliniek voor Inwendige Geneeskunde (Clinic for Internal Medicine) of the Medische Faculteit (Faculty of Medicine), Academisch Ziekenhuis Utrecht (AZU) (University Hospital). The project 'Development of a program for self-tutoring for differential research', from which this anamneses training program came, served as an inventory of the possibilities which the computer has to offer in differential diagnostics (Min, 1982).


Figure 14.2 MacCOAT , a program to train medical student in history taking; writen in MacProlog (Van Oenen, 1889)

14.3 Computer simulation program MACCOAT

The computer simulation program MacCOAT is especially designed by the University of Utrecht in cooparation with the University of Twente, to give students the opportunity to train themselves in taking the anamnesis just as with the program HISTORY TAKING / ANAMNESE (see figure 14.2).

With this program it is possible to simulate a educational doctor-patient environment on the same way as above. The student is able to use the directly accessible patient data bank of the anamnesis training program. The program has 4 simulation patient cases. With this program there is also a system of messages that offers instruction at certain unexpected moments, accoording to Boolean logic. The program is writen in LPA MacProlog.

14.4 Computer simulation / animation program PLC (Programmable Logical Controller)

The computer simulation program PLC for the subject mechanical technics has been developed within a team project between the Stichting voor de Leerplanontwikkeling (SLO) (a foundation for the development of curricula) and the Universiteit Twente. This collaboration wants the University of Twente to develop a number of computer simulation programs together with SLO on computers furnished by SLO. These programs will subsequently find their way into education via SLO.


Figure 14.3 The animation part of the computer simulation program PLC. This program is built in Pascal with the procedure library CAILIB of the University of Twente. This animation part of the program is the simulation part: 'simulation CAL' (Wolters, 1986; Dekker, Van Van Doorn  en Pikaart, 1989)

This simulation program has been developed to introduce students of the LTO (a lower form of technical education) to the operation process in computer-operated apparatus. For it appears that students who have left the LTO are often confronted with such apparatus in their jobs, and are not or insufficiently prepared for it.

Introduction
At junior and senior secondary technical schools learning how to handle and program so-called PLC. A PLC is an important aim. PLC stands for 'programmable logical controller', a programmable apparatus that can operate various other devices. These PLC's are present in industry in various types and shapes. It can be regarded as a (micro)computer that can be programmed on the spot to operate various machines. The 'programming language' is characterized by a high degree of visualization and the ability to link objects in a certain way. The object can be supplied with functions, an activity and a condition for an activity.

At most schools there is only one complete PLC. By a complete PLC is meant: a collection of mechanical pneumatic parts such as pistons, relays etc., which can be mounted in various positions on a large mounting board causing all kinds of activities, provided they are operated by a PLC. This is called a PLC pneumatics set. The SLO at Enschede and the Universiteit Twente participated in this project. Wolters (1986) designed and realized the first version of the computer simulation program PLC on Macintosh. The second version with animation was realized by Dekker, Van Doorn and Pikaart with CAILIB, version 2.0 (see figure 14.3). Moen (1987) has meanwhile realized an MS-DOS version. This was programmed by an external company under direction of the SLO according to Wolter's design. (Wolters, 1987;  Min, 1987; Dekker, Van Doorn and Pikaart , 1989)

Educational value
Usually schools can only afford to buy one completely equipped PLC. Consequently pupils can only practice once or twice a year with the equipment. Programming a PLC requires a great deal of practice in conceptual thinking, and the ability to develop new programs independently and tracing the errors in the programs that have been made. Most schools in the Netherlands use the PLC made by the french firm Telematique. The equipment consists of a PLC and a board that can be fixed on the wall on which cylinders and pistons have been mounted that can be interconnected and influence each other. All this is controlled by the PLC. In order to make the most of the few times the PLC is used, a simulation program called PLC has been developed and realized to train the pupils. With this computer simulation program pupils can be optimally prepared for work in a practical training room with the real apparatus. Beside the fact that many more pupils are now busy with the problematic nature of a PLC and its programming, the quality of the exercises has also increased. The pupils can practice how to make programs independently. As was said earlier, the pupil is actually 'modelling CAL' with this simulation program.
For designing and filling in a function diagram (a program) involves trying to realize a control model based on a conceptual model. The control program ('the model') can be programmed on two levels. Level 1 is programming the function diagram and level 2 is the filling in of the ladder diagram with commands and conditions. These can be indicated by clicking in graphical and numerical symbols. Thus the computer simulation program PLC has become a sort of editor.

To computer simulation program PLC teaches the students how to handle a system with maximally three pistons and 10 actions (steps) and a function diagram and a ladder diagram in order to control the chosen installation with the relevant pistons. Two cases have been developed with the PLC program, one in order to learn how to program a stamping installation with two pistons and another for a 'lifting device' with three pistons. Dekker van Doorn en Pikaart (1989) realized a version of PLC (PLC animation) including a complete animation of a lifting apparatus. If the student programmed the lifting device well, this is represented on the screen in the form of an animation. This forms the end of the lesson with the computer simulation program PLC and is actually 'overall feedback' for the student.

Results
With the computer simulation program PLC the following goals can be reached:

For a survey of the computer simulation program PLC see figure 1.7 in chapter 1

The computer simulation program PLC has yielded good results. It has been tested in three forms of a junior and senior secondary technical school. The accompanying paper materials were approved of. However, SLO has not yet published the three different versions of the PLC program. But research at the University of Twente to achieve an even better concept and userinterface continues.

14. 5 The computer simulation program SEFLOW / FLOWSIM (hydrodynamic model / Waterloopkundig laboratorium)

Introduction
At the Waterloopkundig Laboratorium (Hydrodynamic Laboratory) in the Flevopolder, Marknesse in the Netherlands, a mathematical model is used that can calculate the course of the flow and the sediment in a river or canal. For example it can calculate the level of the water lines from the movements of the tides at the river mouth. It can also calculate the influence of rain in the hinterland. The mathematical model is called SEFLOW. The training program has been made by the University of Twente together with the Hydrodynamic Laboratory which has for this occasion lent the model developed by them in order to have a complete computer simulation program built around it that can be used for educational purposes. The computer simulation program will contain a series of cases ascending in measure of difficulty so that course members can be trained for the more difficult phase later on in their study: the modelling process of any river or canal itself. The first prototype has been delivered by the University of Twente on an ATARI 1040ST with the GEM operating system.

Model
At the Waterloopkundig Laboratorium water flows are studied in rivers and in the sea with a lot of physical, geometrical and mathematical models. In practice the construction, calibration and validation of mathematical models requires a lot of time and sometimes the results are not accurate enough. The experience of the user plays an important role, particularly with respect to his or her knowledge of physics. For this purpose the program FLOWSIM has been developed (see figure 14.4). FLOWSIM is an interactive training program to gain insight into the response of flow through networks, such as rivers and canals. Up till now it has been constructed as a 'shell' around the FLOW part of SEFLOW and in future it can be extended to any program.


Figure 14.4 . The input-window, treee output windows and one intervation  sub-window of the computer simulation program FLOWSIM on Atari 1040 ST with the model WAFLOW (Zwart, 1989) On this windows a river flows from left to right. On several points the water level and the flow can be registrated. Also parameters can be changed interactivelly

Results
FLOWSIM enables the user to exercise real simulations on various models while not being confronted with difficult and time-consuming aspects such as model schematization, data-input, preprocessing and postprocessing. By introducing a change into the system and running a new computation, the influence on water levels and flow velocities will be illustrated. In this way the user gets a feeling of the system's response to changes in boundary conditions, bottom roughness, inclination of the waterway, and so on. An instruction manual, providing the elementary physical background, will guide the user during the exercises. The program is now (1991) available on an MS-DOS computer with an GEM operating system. (Zwart, 1989)

14. 6 The computer simulation program SATSIM (Fokker Space & Systems)

Introduction
At Fokker Space and Systems, in the Netherlands (Amsterdam) a mathematical model is used that can calculate the position of a satallite in space. It is used for the dutch satallite that will be ready in 1993/94. Ter Hedde developed an animation version for training purposes and describes a prototype, named INSAN / SATSIM on a VAX computer (see figure 14.5). (Ter Hedde, 1989)


Figure 14.5. INSAN / SATSIM, a computer simulation/animation program that simulates the position of a dutch satallite in space, calculates the traject and gives in indication of the position of the sun on an indicator (Ter Hedde, 1989).

14.7 The computer simulation program HOSPITAL / ZIEKENHUIS

Introduction
The computer simulation program HOSPITAL / ZIEKENHUIS was developed by Botter, Universiteit Twente (1990) together with Talman and Houben, Universiteit Limburg, Schoenmaker of the Educational Computer Consortium (ECC) at Enschede.
The Universiteit Limburg provided a complete model that was working well of bed occupancy in a hospital, written in a higher programming language. Botter implemented this model into a SmallTalk learning and simulation environment.

Model
The model of the computer simulation program HOSPITAL / ZIEKENHUIS contains a system of bed occupancy. The model simulates part of a flow of patients who are in a hospital with a capacity for 600 beds. The flow of patients results in a specific bed, xxx occupancy depending on the control model (way of reservation).


Fig. 14.6. The conceptual scheme of 'flow' of patients through the hospital (Botter, 1990)

This is what the trainee wants to find out. The model consists of the following parts:

The hospital model has five departments, with a number of beds in each ward divided between rooms for two and for four persons. Emergency patients are immediately admitted
to beds that have been reserved for this purpose in the ward, whereas ordinary patients are put on a waiting list. Every day a number of patients is released and a number of patients from the waiting list are admitted. Here the principle holds true: First come, first served. The model registers how many patients are admitted , refused and released, what the bed occupancy is and how long one has to wait. Non emergency patients are also classified, viz. patients who should treated before a certain date and those that are not urgent, who can be admitted any time. Emergency patients are generated through a Poisson division, with an average determined by the user. Non-emergency patients are also simulated by means of a Poisson division and 25% of these gets an urgency of 11 days at the maximum. Of every patient the age, sex, ward (in fact determining the disease category) and the duration of the stay in hospital is determined.

Program
The computer simulation program HOSPITAL / ZIEKENHUIS has five wards:

Every ward has a number of beds that can be changed, divided between rooms for two and for four persons. There are an equal number of either. Every room has patients belonging to the same sex and the difference in age is 15 years at the most.

When a patient is admitted he or she is entitled to the means of the hospital. The patient will occupy a bed for a certain period of time, and will affect the pressure of work on the medical and nursing staff. In order to control the effect of these data, a control model and a measure for its efficiency has been determined.  The measure for the efficiency is determined by in how far the hospital's aim is achieved. The aim is optimalization of the bed occupancy on the following conditions:

Results
The program HOSPITAL / ZIEKENHUIS was successfully programmed in Smalltalk. The results achieved during the design and realization phase are in short:
Interaction with the hospital model is difficult to optimalize in Smalltalk. It proved impossible to produce an equally perfect userinterface within the framework of this project as with Mac THESIS software;
For the time being procedure libraries do not allow the linking up of all kinds of animation tools  to the model, such as 'Toolbox' of Macintosh;
Smalltalk is too difficult a language to master reasonably within six months. Once one knows the language it is relatively simple to make a program based on earlier prototypes.

As a prototype the program HOSPITAL / ZIEKENHUIS  can certainly be called a success. This results in further research into object oriented languages at the Universiteit Twente.

Note
The paragraph about the computer simulation program SEFLOW / FLOWSIM, paragraph 14.5, is original writen by W.J. Zwart & F.B.M. Min.

The paragraph about the computer simulation program SATSIM, paragraph 14.6, is original writen by  R. ter Hedde & F.B.M. Min.

The paragraph about the computer simulation program HOSPITAL / ZIEKENHUIS, paragraph 14.7, is original writen by  B. Botter & F.B.M. Min.