Dealing with Uncertainty of User Knowledge: Fuzzy User Modelling in Educational Hypermedia

An adaptive educational system is a Web-based hypermedia system that incorporates complex intelligent tutoring techniques, which enable the system to recognize an individual user, their needs and consequently adapt the instructional sequence. The system builds on the concept domain model and includes the elements of knowledge uncertainty in the process of user modelling. The personalization is done through the user model, which collects information about the user. Since the description of user knowledge and features also involves imprecision and vagueness, a user model has to be designed that is able to deal with this uncertainty. The domain and user models are used for adapting system’s navigation support to an individual user. This paper presents a way of describing the uncertainty of user knowledge, which is used for user knowledge modelling in an adaptive educational system. A fuzzy user model is proposed to deal with vagueness in user knowledge description. The model uses fuzzy sets for knowledge representation and fuzzy rules for model updating. The evaluation of the presented educational system has shown that the system and its adaptation techniques provide a valuable, easy-to-use tool, which positively affects user knowledge acquisition and therefore leads to better learning results.