Design issues for general-purpose adaptive hypermedia systems

A hypermedia application offers its users much freedom to navigate through a large hyperspace. For authors finding a good compromise between offering navigational freedom and offering guidance is difficult, especially in applications that target a broad audience. Adaptive hypermedia (AH) offers (automatically generated) personalized content and navigation support, so the choice between freedom and guidance can be made on an individual basis. Many adaptive hypermedia systems (AHS) are tightly integrated with one specific application. In this paper we study design issues for general-purpose adaptive hypermedia systems, built according to an application-independent architecture. We use the Dexter-based AHAM reference model for adaptive hypermedia [7] to describe the functionality of such systems at the conceptual level. We concentrate on the architecture and behavior of a general-purpose adaptive engine. Such an engine performs adaptation and updates the user model according to a set of adaptation rules specified in an adaptation model. In our study of the behavior of such a system we concentrate on the issues of termination and confluence, which are important to detect potential problems in an adaptive hypermedia application. We draw parallels with static rule analysis in active database systems [1,2]. By using common properties of AIIS we are able to obtain more precise (less conservative) results for AHS than for active databases in general, especially for the problem of termination.