Title:Designing Web User Interfaces Adaptable to Different Types of Use
Authors:Fabio Paterno
Publication:MW99: Museums and the Web 1999

The user access to a web interface of a museum application can have many motivations. There are various types of users, who want to perform various tasks, in various contexts, that can access to the same web site. Thus it is important to have user interfaces able to adapt to these different user requirements to facilitate the accomplishment of the desired goals. In the paper we want to discuss different techniques to design such adaptable interfaces for museum web sites and provide examples of applications of some of them by considering the type of impact that they can have in a web interface for the Marble Museum located in Carrara (Italy). Currently in the application for the Marble Museum, at the beginning the user can select a visitor profile (e.g. expert, art-student or tourist), and during the virtual visit the user has the opportunity to change this profile. Thus the system is adaptable because the user can modify the profile parameter and the system changes its behaviour accordingly. Adaptation can occur at three levels: Presentation, where it is possible to differentiate the type of media, the layout, the attributes of the perceivable elements (such as font type and size) depending on the type of access; Information, where the information content can be changed, sometime drastically, even if related to the same topic, depending on the type of user and the use foreseen; Navigation, where different links are provided, in some cases in different locations and with different appearance. Adaptation can be done manually by users who explicitly indicate some parameters useful for understanding their needs or it can be done automatically by the system (in this case many authors define the interface as adaptive). Generally speaking, user models can be static or dynamic. In static models, user knowledge is represented as 'topic-value' pairs but the values are not completely independent. The user can be assigned to one or more stereotypes (for example novice - intermediate - expert). Each stereotype is characterised by a fixed set of pairs 'topic-value' and the user assigned to a stereotype inherits all these properties. This modelling is reliable enough and works well for a system that needs to adapt to different classes of users. In the dynamic model for each domain model topic there is some estimation of how well the user is familiar with this topic and this estimation takes into account the history of previous accesses to the application. In dynamic modelling it is possible to measure user knowledge with more flexibility. The static models are simpler than dynamic modelling, but less powerful. Good results can be achieved by combining stereotype and overlay modelling. One possible way to combine these two techniques: static modelling is used to determine the class of the user and to assign initial values for the dynamic model. Then dynamic modelling is used to keep the model updated.