A TASK-CENTERED APPROACH FOR USER MODELING IN A HYPERMEDIA OFFICE DOCUMENTATION SYSTEM

The development of user-adaptive systems is of increasing importance f or industrial applications. User modeling emerged from the need to rep resent in the system knowledge about the user in order to allow inform ed decisions on how to adapt to match the user's needs. Most of Be res earch in this field, however, has been theoretical, ''top-down.'' Our approach, in contrast, was driven by the needs of the application and shows features of bottom-up, user-centered design. We have implemented a user modeling component supporting a task-based interface to a hype rmedia information system for hospitals and tested it under realistic conditions. A new architecture for user modeling has been developed wh ich focuses on the tasks performed by users. It allows adaptive browsi ng support for users with different level of experience, and a level o f adaptability. The requirements analysis shows that the differences i n the information needs of users with different levels of experience a re not only quantitative, but qualitative. Experienced users are not o nly able to cope with a wider browsing space, but sometimes prefer to organize their search in a different way. That is why the user model a nd the interface of the system are designed to support a smooth transi tion in the access options provided to novice users and to expert user s.