Nomadic radio: speech and audio interaction for contextual messaging in nomadic environments

Mobile workers need seamless access to communication and information services while on the move. However, current solutions overwhelm users with intrusive interfaces and ambiguous notifications. This article discusses the interaction techniques developed for Nomadic Radio, a wearable computing platform for managing voice and text-based messages in a nomadic environment. Nomadic Radio employs an auditory user interface, which synchronizes speech recognition, speech synthesis, nonspeech audio, and spatial presentation of digital audio, for navigating among messages as well as asynchonous notific ation of nely arrived messages. Emphasis is placed on an auditory modality as Nomadic Radio is designed to be used while performing other tasks in a user's everyday environment; a range of auditory cues provides peripheral awareness of incoming messages. Notification is adaptive and cntext sensitive; messages are presented as more or less obtrsive based on importance inferred from content filtering, whether the user is engaged in conversation and his or her own recent responses to prior messages. Auditory notifications are dynamically scaled from ambient sound through recorded voice cues up to message summaries. Iterative design and a preliminary user evaluation suggest that audio is an appropriate medium for mobile messaging, but that care must be taken to minimally intrude on the wearer's social and physical environment.