... Web PVT), an adaptive web-based Intelligent Computer Assisted Language Learning (ICALL) program that is aimed at teaching non-native speakers the passive voice of the English language. The design of the system has been largely based on the results of an empirical study that was conducted at schools with the collaboration of human teachers. Web PVT incorporates techniques from Intelligent Tutoring Systems (ITS) and Adaptive Hypermedia (AH) technologies to provide students with individualised instruction and feedback. The system uses a combination of stereotypes and the overlay technique for the initialisation of the student model, which is then refined by observing the student while working with the system. The resulting student model is used for the annotation of the links to topics presented to the student. In addition, it is also used in the process of error diagnosis and the adaptation of feedback and advice provided to the student.

This paper describes the student modelling component of Web-EasyMath, an adaptive Web-based Intelligent Tutoring System that is aimed at teaching the domain of algebraic powers. The system constracts a short and a long term student model based on a combination of stereotypes and the overlay technique. The long term model is updated based on a data ageing mechanism, leading to a student model that reflects the current knowledge state of the student.