User-Centred Design of Flexible Hypermedia for a Mobile Guide: Reflections on the HyperAudio Experience
User modeling and user-adapted interaction
Published paper Petrelli, D. and Not, E. (2005) User-centred design of flexible hypermedia for a mobile guide: Reflections on the hyperaudio experience, User Modeling and User-Adapted Interaction, Volume 15 (3 -4), 303 -338. Abstract. A user-centred design approach involves end-users from the very beginning. Considering users at the early stages compels designers to think in terms of utility and usability and helps develop the system on what is actually needed. This paper discusses the case of
... yperAudio, a context-sensitive adaptive and mobile guide to museums developed in the late 90s. User requirements were collected via a survey to understand visitors' profiles and visit styles in Natural Science museums. The knowledge acquired supported the specification of system requirements, helping defining user model, data structure and adaptive behaviour of the system. User requirements guided the design decisions on what could be implemented by using simple adaptable triggers and what instead needed more sophisticated adaptive techniques, a fundamental choice when all the computation must be done on a PDA. Graphical and interactive environments for developing and testing complex adaptive systems are discussed as a further step towards an iterative design that considers the user interaction a central point. The paper discusses how such an environment allows designers and developers to experiment with different system's behaviours and to widely test it under realistic conditions by simulation of the actual context evolving over time. The understanding gained in HyperAudio is then considered in the perspective of the developments that followed that first experience: our findings seem still valid despite the passed time. The original publication will be available at http://www.springerlink.com/ As discussed above, applying UCD to the design of adaptive systems is particularly challenging because the behaviour of the final system is intended to dynamically adjust according to multiple parameters, i.e. user preferences, knowledge and behaviour, and interaction context. When, in the mid 90s, we first started working on one of the first prototypes of adaptive and mobile museum guide (called HyperAudio, Not et al., 1997a), not much experience was available in the Adaptive Hypermedia community on how to export principles of adaptivity to mobile applications, nor much skill was available on the application of UCD to adaptive systems. In the initial critical phase of the project we faced problems like envisaging credible scenarios of use, identifying parameters for adaptivity, designing content and adaptation rules in a suitable way. The initial aim we had in mind was to offer the visitor personalized information centred on his/her current standing position. The envisaged interface was a web-based layout with an active involvement of browsing users. What the final development of HyperAudio offered instead was an experience of freely moving in an information space and automatically receiving tailored information. We 2 Exceptions are web-based recommendation systems that make use of massive logs of user profile/behavior to select the most appropriate information and in general to implement adaptivity (Kobsa et al., 2001) .