ECCLES: AN 'EXPERT SYSTEM' FOR C.A.L.
Thomas J. Richards, Geoffrey I. Webb · 1985
An authoring and lesson management system is described for Computer Assisted Learning in which lesson questioning and control flow arising from student response are generated at lesson time from an internal model of the lesson topic area. This approach permits the rapid authoring of conceptually complex lesson material. A languageless menu—driven authoring system rninimises the system familiarization time for lesson authors and enforces the construction of logically complete lessons. From the student’s point of view, the system appears as an expert system in the lesson subject area, with precise and detailed knowledge of the topic taught and of the causes of the student’s own errors. 1 QUESTION STRUCTURE AND TOPIC STRUCTURE ‘ECCLES’ stands for ‘Epistemically Complex Courseware Lesson Executive System’, which on the face of it is yet another authoring, lesson dispensing and student record management software package of the test-and-branch variety. Certainly in ECCLES a student gets asked questions about a chosen topic; and certainly his or her replies will affect what questions are asked next. But at that superficial level of student interface the similarity ends, for in ECCLES the student interaction sequence is generated by software that describes the topic not the questions. ECCLES can be thought of as an expert system that under stands the topic area it is going to teach, and uses that understanding to drive the student interaction. This has some significant consequences, notably for the lesson author. In the normal type of testand-branch CAL system, which we call question-driven, the flow of control through the teaching materials is determined by the interaction of the student’s answers with a complex schedule, usually tree-structured, of questions, sub-questions, and sub-sub-questions; all of which have to be thought up by the lesson author and specifically authored into the lesson file. Moreover, in many cases the author wishes to submit to the student tens of hundreds of ‘topic items’ for analysis, so must then write a tree of specific questions for each such item. In such cases it is easy to see why authors find the authoring to running time ratio is about a hundred to one. And it is in just such cases that ECCLES offers an alternative approach. In ECCLES the author enters, just once, a description of the lesson topic area, plus a list of the topic items, and ECCLES does the rest. We have found that this reduces authoring time to something of the order of the running time. More significantly perhaps, it means that the devising of Complex and comprehensive lessons on complicated subject material is now a realistic activity. We will make these remarks more concrete with an example.