Generation of Questions Sequences in Intelligent Teaching Systems Based on Algebraic Аpproach

The paper describes an approach to development of question-and-answer teaching systems based on controlled languages and algebraic models for representation and processing of question-and-answer texts. We propose using a partial order relation "question-subquestion" to build an individual trajectory of teaching. To model a strategy of examination, we use defeasible reasoning formalized within our earlier developed QC-structures. perceived knowledge and to advise ways for its improving. An ITS controls a question-and-answer dialog to appraise student's knowledge. The unit simulating teacher's examination strategies plays an important role in this dialog. It also provides revision of estimates of student's knowledge accumulated during examination. The situation becomes more complicated when this dialog stipulates natural language communication with "arbitrary" shapes of answers. The term "arbitrary" is not quite correct as the student is supposed to be familiar with the teaching material i.e. immersed into the context. This means the student ought to give reasonable answers within the terminology relevant to the teaching material.