Script-Based Tutor: A Direct Tutorial Strategy for Intelligent CAI for Acquiring Skills of Circuit Analysis

Abstract

This paper presents a script-based tutor installed in an intelligent computer-aided instruction system. We assumed that knowledge is first acquired declaratively through instruction and that it has to be converted into and recognized as procedures through experience. The assumption suggests that learning by doing problem-solving allows students, who at first must have gained the declarative knowledge in lectures, to strengthen the declarative knowledge and acquire the procedural knowledge or skills. The tutoring system can offer students such a practicing environment. Primitive knowledge in the system is composed of declarative knowledge of electrical circuit analysis. Scripts incorporate compiled expertise of primitive knowledge and procedures for solving electrical circuit problems. A script is an ideal model of a problem-solving plan represented by correct knowledge and procedures. A script is a collection of slots for events that provides conceptual dependency between them. The events are caused by the student's activities in his own problem-solving attempt. For example, when he describes his actions by sentences and equations. Actions are evaluated by a rule-based diagnosis module, and the slots of the script are filled with the results. Therefore the student model in the system is formed as an overlay on the script. The script-based tutor uses a direct tutorial strategy that consists of local tactics and global tactics. The direct tutor guides the student's behavior by direct indication of errors and explanation of procedures. In addition, the student's abilities are improved via practice. The local tactics provide students with immediate feedback on incorrect actions and requests for assistance. The feedback merely confirms the student's correct action and gives the remedies for his errors. When the errors or impasses in the student's problem-solving attempt are originated in misunderstanding or forgetfulness, he can request for explanation of primitive knowledge and procedures. This tutoring tactic is similar to Anderson's model tracing, because the student is made to follow one of the system's ideal models quite closely. The global tactics provide a global evaluation of the script of the just-completed problem and an assessment of the student's problem-solving performance. In addition, the next problem is chosen from the problem file, where the sequence can be tailored depending on each student's understanding. In this way, adaptive tutoring is achieved.