AHA! adaptive hypermedia for all

There are roughly two types of (Web-based or other) Adaptive hypermedia systems (AHS): special-purpose systems, geared towards one specific application or application area, and general-purpose systems, designed with different applications in mind. Most existing systems are special-purpose, with a majority aiming at educational applications. Previous developments on the AHA system (De Bra & Calvi, 1998) and the AHAM model (De Bra et al, 1999) have shown that general-purpose AHS can be designed and implemented, but also that such systems tend to be too complicated for non-technical authors. This paper describes the "third generation AHA", called Adaptive Hypermedia for All, which is being developed as an open source project sponsored by the NLnet Foundation. AHA aims at bringing adaptivity to all kinds of Web-based applications, through a simple but powerful adaptive engine. In this paper we focus on the authoring interface for creating the conceptual structure of an adaptive application. But we also briefly describe how the AHA system can be used for some typical constructs found in (adaptive) Web-based applications.