Marcus Nyberg

Providing proper affordances when transferring source metaphors from information appliances to a 3G mobile multipurpose handset

The idea of merging different information appliances, each tailored to fit a specific task, into a multipurpose 3G mobile handset has become an interesting research area. This paper describes what considerations must be met from an efficiency point of view when designing a multipurpose handset concept including, e.g., camera functionality. The lessons learned when trading well-known previously acquired source metaphors for the “computer metaphor” was investigated in a small usability evaluation with 14 users, evaluating a multipurpose prototype. High task accuracy (effectiveness) was obtained (72% pass), but the efficiency with which the tasks were performed compared to using dedicated information appliances was low. Leaving out well-known affordances effectively prevented transfer of previously acquired source metaphors, which resulted in lack of feedback, inconsistency and errors. In order to validate usability, a combination of both objective and subjective metrics has to be used.

Visualising data using the ActionMapper: a proposed interactive event logger for user interface evaluation

The proposed ActionMapper tool extends previous work on the generic KeystrokeMapper tool to provide an efficient method of logging and visualising a novice users interaction with a dynamic interface. For any specified task the ActionMapper could generate a graphic representation of both the designers conceptual model (represented by an Optimum path) and an indication of the users mental model (represented by the actual path navigated by the user). In this study, the results from two usability experiments have been analysed using the KeystrokeMapper concept. From this a refined version of the tool, referred to as ActionMapper, is outlined. It is argued that the future implementation of the ActionMapper concept as a computer-based tool, which includes the automatic analysis and visualisation of numerous usability metrics, will substantially enhance the evaluation process. By adding event recording functionality in a prototype for a small handheld device, effective usability evaluations could also be conducted in a mobile context.