Abstract. We investigate the use of 2 tagging technologies: Near Field Communication (NFC) and 2-dimensional barcodes. Our investigation combined a field trial and interview based study with an experimental evaluation. The field trial focused on users' experience of the usability of NFC for a range of trial services, users' perceptions of NFC use in their daily life context, and users' suggestions for potential applications of NFC. The tags were embedded in a variety of postcards, table-top signs and posters. The experimental evaluation compared the ease of use of NFC and 2D barcodes, operationalised in terms of time taken to read a specified sequence of tags on posters. We found that for untrained users the 2D barcodes were quicker to use than the NFC tags but that training significantly improved users' performance with the NFC tags while having no effect on their performance with the barcodes.

With an ever increasing number of mobile services, meaningful audio notifications could effectively inform users of the incoming services while minimising undesired and intrusive interruptions. Therefore, careful design of mobile service notification is needed. In this paper we evaluate two types of audio (auditory icons and earcons) as mobile service notifications, by comparing them on 4 measures: intuitiveness, learnability, memorability and user preference. A 4-stage longitudinal evaluation involving two lab experiments, a field study and a web-based experiment indicated that auditory icons performed significantly better in all measures. Implications for mobile audio notification design are presented.

It is hoped that context-aware systems will present users with an increasing number of relevant services in an increasingly wide range of contexts. With this expansion, numerous service notifications could overwhelm users. Therefore, careful design of the notification mechanism is needed. In this paper, we investigate how semantic richness of different types of audio stimuli can be utilised to shape the intuitiveness of mobile service notifications. In order to do so, we first develop a categorisation of mobile services so that clustered services can share the same notifications. Not surprisingly, it was found that overall speech performed better than non-speech sounds, and auditory icons performed overall better than earcons. However, exceptions were observed when richer semantics were utilised in the seemingly poorer medium. We argue that success and subjective preference of auditory mobile service notifications heavily depends on the success and level of directness of the metaphors used.

There is evidence that most users do not exploit the capabilities offered by mobile data services. We propose that in addition to user requirements and usability, service discovery adds an extra dimension that may explain this lack of use. We conducted a 3-way evaluation study which combined expert evaluation, a diary study and cooperative evaluation to investigate the factors affecting low usage of data services. The task of selecting the appropriate service to solve everyday problems was demonstrated to be difficult using existing mobile services. The results indicated that service discovery plays a central role in determining user satisfaction and performance.

No abstract