== only for educational use ==

A small Expert System
(version 1.0x)

Rik Min and Casper Bleys

(Dr. ir. R. Min: multimedia specialist from the Faculty of Educational Science and Technology; University of Twente)
(Dr. C. Bleys: medical specialist from the Medical Faculty; University of Utrecht)

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:

In chapter 1 of my book (1996) (see elswhere on my WEB-site) 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 .i.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:

with yes, no, yes, yes, no, yes and no. The computer program PHYSICIAN / ARTS answers:

The computer program containing the expert system has been developed at the University of 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. 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. Now there is a fourth online WEB-version.

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.

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.


Start ARTS, by clicking in yes or no

So The most probable diagnosis is with a probability of (with a maximum of 1 and a minimum of 0).

The evaluation

De evaluatie van de diagnose is uit de volgende tabel met de apriori kansen af te leiden:
klacht 1:
klacht 2:
klacht 3:
klacht 4:
klacht 5:
klacht 6:
klacht 7:
In deze evaluatie-tabel ziet u de invloed van het antwoord ja en van het antwoord nee. Bij het antwoord ja wordt de uitgangs-kans p(vraag/ziekte) gekozen om p(ziekte/vraag) te rekenen. Bij nee is 1 minus die uitgangs-kans gekozen om te rekenen. U kunt dus aan de hoogtste getallen - als extra controle - zien dat het ook logisch is dat 'ik', als ARTS, met die gegevens - die waarden - wel MOET concluderen dat wat ik hierboven zojuist vertelde. U ziet 'als het ware' het pad waarlangs ik gelopen ben om tot de ziekte te komen. De kolom met de hoogste totale waarde is de kolom van de ziekte; die ziekte heb 'ik' derhalve - door berekening - gekozen. U ziet het: u heeft er met deze evaluatie nog een visulele ckeck bij. Tel maar op en reken maar na.

Let op:

PS. Dit was en is mijn
kladblok (form 20):

PS. Dit is mijn
andere kladblok (form 21):

Enschede, 1988 - 2001; updated: 20 april 2001.