Tutoring in computerised environments of learning : Study of design and realisation of a tutorial helping the elaboration of the physical representation of mechanics' situation
Angélique Dimitracopoulou, 1995. 
This research concerns the design, the realisation and the evaluation of an intelligent tutoring system. The modelling of tutorial processes is a crucial question in the field of computational didactic. ARPIA is a tutorial devoted to guide and aid the elaboration of the physical representation of situations in mechanics. Our target is to help the students (between 17-19 years old) who had followed a course in mechanics and already face difficulties in developing a physical representation of situations (Forces diagrams and Motion diagrams). It is interactive and adapted to the learner. 
The theoretical framework for this tutorial design is based on a precise didactic analysis that is to say : an epistemological analysis of the content a cognitive analysis of the used tasks, an analysis of students' difficulties, and a clarification of learning hypothesis. 
The communication interface has been designed in order to allow the student to construct directly his representation (for instance by drawing vectors). 
The process of cognitive diagnosis identifies and interprets each element of the student's representation. It builds a current " student model " taking into account the whole set of answers given previously by the student (right and false answers) and the whole set of previously occurred interactions. This " student model " evolves at each new answer or new interaction.The choice, by the tutorial, of a new interaction relies on this student model and on pedagogical principles. In designing ARPIA a special interest was devoted to define and realise several kinds of didactic actions. 
The prototype ARPIA uses eight types of action : 
•	control of communication rules, 
•	validation and institutionalisation, 
•	advice for use of a technique, 
•	error correction by the system, 
•	process of error correction by the student himself, 
•	process of explanation, 
•	summing up. 
A key idea is that an explanation is accepted by the student only if he is aware of a difficulty or an error. Without this awareness any explanation is useless. So, for instance in the " process of explanation ", the first step consists in making the student conscious of what " goes wrong ". If a force diagram, proposed by the student, is wrong the system shows the real physical situation represented by the force diagram proposed by the student and asks for comparison of the two (different) physical situations. After each comparison the system gives the student the opportunity for changing his diagram. Generally, the students, once aware that there is a problem, rectify by themselves. 
With the kind of evolving student model as a basis for the choice of the tutorial actions and the variety of these tutorial actions, the program is adapted to the students' cognitive needs as well at there cognitive potentialities. 
The tutorial's evaluation showed that it is effectively pertinent for the learning of the physical representation and thrown light about ways for improvement and possible extensions.