Abstract. The paper reviews the development of generic user modeling systems over the past twenty years. It describes their purposes, their services within user-adaptive systems, and the different design requirements for research prototypes and commercially deployed servers. It discusses the architectures that have been explored so far, namely shell systems that form part of the application, central server systems that communicate with several applications, and possible future user modeling agents that physically follow the user. Several implemented research prototypes and commercial systems are brie£y described.
In REF , the authors surveyed the state-of-the-art research of general user modeling systems, and discussed the requirements that will facilitate their wide dissemination for both academic and commercial purposes:
Generic User Modeling Systems
User Modeling and User-Adapted Interaction
User Modeling and User-Adapted Interaction
Computer Science