With the proliferation of mobile devices it has become common to see groups of users working or playing together using multiple mobile devices. While much effort is exerted to ensure that interaction with a mobile device is useful for each individual user, less effort has gone into considering how to design and evaluate mobile interfaces and platforms for group use. Recent improvements in the interaction, computing, connectivity and general flexibility of mobile devices make them an ideal, yet underutilized, platform for group level interaction. Our goal with this workshop is to bring together researchers who have started to investigate the collocated group use of mobile devices and to shed light on the challenges of designing and evaluating mobile collocated group experiences.

International and intercultural collaborations provide a unique opportunity to explore cultural differences in the usage and appropriation of a technology. Mobile photo capture and sharing has been growing in popularity in the Western world but nowhere has the practice been as eagerly adopted as in South Korea. In this paper we present an evaluation of a mobile-collocated photo sharing technology probe designed to determine the ways in which photo capture and sharing can effect and enhance face-to-face interaction for pre-existing social groups. We explore the interaction of culture and automatic, real-time photo capture and sharing on groups of friends engaging in a walking tour. We assemble a multicultural research team to better understand our observations and isolate cultural and technological artifacts. We relate our findings to prior work in the area to show that culture can have as much, if not more, impact on group usage of a technology than the technical capabilities of a system.

My research examines challenges inherent in the design of mobile groupware systems. For my thesis work I am designing interfaces and interaction techniques that can be used to augment face-to-face communication within groups of collocated mobile users. In my initial research, which explored collocated mobile photo capture and sharing, I uncovered three fundamental challenges to designing mobile groupware. In this paper I discuss these challenges as well as my proposed research agenda to addresses the challenges.

When designing a text entry system for mobile phone keypads, a designer needs to overcome the ambiguity that arises from mapping the 26 letters of the roman alphabet to only 12 keys (0--9, *, #). In this paper, we present a novel two-thumb chording system for text entry on a standard 12-key mobile phone keypad and introduce a performance model based on Fitts' Law for an expert user. The model provides a behavioral description of the user and predicts a text entry rate of 55.02 wpm.

We investigate the effect of placement and user mobility on the time required to access an on-body interface. In our study, a wrist-mounted system was significantly faster to access than a device stored in the pocket or mounted on the hip. In the latter two conditions, 78% of the time it took to access the device was spent retrieving the device from its holder. As mobile devices are beginning to include peripherals (for example, Bluetooth headsets and watches connected to a mobile phone stored in the pocket), these results may help guide interface designers with respect to distributing functions across the body between peripherals.

People use photographs for numerous reasons with one of the most common uses of both analog and digital photographs is as an artifact to share and discuss with others. While the practice of photo sharing has been thoroughly examined in the HCI community, there is currently very little research on easily capturing and sharing content within groups of collocated mobile users. In this paper we present the design, implementation, and evaluation of a mobile photo sharing application, Mobiphos, that gives a group of collocated users the ability to capture and simultaneously share photos in real-time with each other.

In this paper we present a 20-participant controlled experiment to evaluate and compare a head-down visual display and a synthesized speech audio display for comprehending text while mobile. Participants completed reading comprehension trials while walking a path and sitting. We examine overall performance and perceived workload for four conditions: audio-walking, audio-sitting, visual-walking, and visual-sitting. Results suggest audio is an acceptable modality for mobile comprehension of text. Participants' comprehension scores for the audio-walking condition were comparable to the scores for the visual-walking condition. More importantly, participants saw improvements in their ability to navigate the environment when using the audio display.