There have been many large-scale investigations of users' mobile app launch behaviour, but all have been conducted on Android, even though recent reports suggest iPhones account for a third of all smartphones in use. We report on the first large-scale analysis of app usage patterns on iPhones. We conduct a reproduction study with a cohort of over 10,000 jailbroken iPhone users, reproducing several studies previously conducted on Android devices. We find some differences, but also significant similarities: e.g. communications apps are the most used on both platforms; similar patterns are apparent of few apps being very popular but there existing a 'long tail' of many apps used by the population; users show similar patterns of 'micro-usage': almost identical proportions of people use a unique combination of apps. Such similarities add confidence but also specificity about claims of consistency across smartphones. As well as presenting our findings, we discuss issues involved in reproducing studies across platforms.

paper discusses our experiences in logging app use on computers, mobile phones and tablets. We have created logging software to record app launches on iOS, Android and Mac OS X devices, and have used this in a study with 13 students over a period of one month. This paper discusses the practicalities of logging across multiple devices, the forms of enquiry suitable for log analysis, and the ethics of logging. We also discuss future work in which we will scale the study up to thousands of users.

This paper demonstrates strategies for designing mobile games with by-products in order to allow the acquisition of specific data. A mobile game with by-products called EyeSpy and a photo website called Realise will be used as examples to demonstrate these strategies. The Realise website allows users to browse geographically tagged photos and make specific requests for new ones. In the EyeSpy game, players use mobile phones to tag geographic positions with photos and text. EyeSpy players can earn points from validating each others' tags by visiting tag locations and attempting to 'confirm' them. If players go to the correct location, both the player confirming the tag and the player who created it will gain points. This creates game content for EyeSpy and provides more refined results for the Realise website. In this way, both the systems mutually reinforce each other.

This paper demonstrates how useful content can be generated as a by-product of an enjoyable mobile multiplayer game. In EyeSpy, players tag geographic locations with photos or text. By locating the places in which other players' tags were created and 'confirming' them, players earn points for themselves and verify the tags' locations. As a side effect of game-play, EyeSpy produces a collection of recognisable and findable geographic details, in the form of photographs and text tags, that can be repurposed to support navigation tasks. Two user trials of the game successfully produced an archive of geo-located photographs and tags, and in a follow-up experiment we compared performance in a navigation task using photographs from the game, with geo-referenced photos collected from the Flickr website. Our experiences with EyeSpy support reflection upon the design challenges presented by 'human computation' and the production of usable by-products through mobile game-play.

We describe work in progress on tools and infrastructure to support adaptive component-based software for mobile devices 'in our case, Apple iPhones. Our high level aim is 'design for appropriation', i.e. system design for uses and contexts that designers may not be able to fully predict or model in advance. Logs of users' system operation are streamed back in real time to evaluators' data visualisation tools, so that they can assess design problems and opportunities. Evaluators and developers can then create new software components that are sent to the mobile devices. These components are either integrated automatically on the fly, or offered as recommendations for users to accept or reject. By connecting developers, users, and evaluators, we aim to quicken the pace of iterative design so as to improve the process of creating and sustaining contextually fitting software.

Recent advances in mobile device technology have opened up new possibilities in enhancing the experience of spectators at stadium-based sporting events. In creating novel applications for use in such settings, designers must be aware of the current practices of spectators and of features of the environment at such events that novel applications may seek to exploit. This work forms an early part of the Designing the Augmented Stadium project. Data sets have been collected from spectators, logging the results of Bluetooth scans alongside GPS location. This paper presents an information visualization tool that can be used in the analysis and exploration of this data, to provide insight into the activities of spectators, the relationship between an individual spectator and the crowd as a whole and the suitability of stadium environments for applications based on infrastructure such as mobile ad hoc networks (MANETs) and wireless mesh networking. Various visualization tools are described and example cases are illustrated, using several real-world data sets recorded at football matches.

This paper investigates emergent practices around 'microblogging', changing and sharing status within a social group. We present results from a trial of 'Connecto', a phone based status and location sharing application that allows a group to 'tag' areas and have individuals' locations shared automatically on a mobile phone. In use the system moved beyond being an awareness tool to a way of continuing the ongoing 'story' of conversations within the group. Through sharing status and location the system supported each groups' ongoing repartee - a site for social exchange, enjoyment and friendship.

Adaptive systems are often constrained by the complexity of designing for unexpected uses and preferences, integrating new software into existing systems, and supporting users in understanding and controlling system structure. In our system, Domino adaptation is driven by recommendations generated from logs of users’ activity. More efficient and enjoyable functionality can be gained through contact with other users who have been in a similar context. We demonstrate the use and utility of the approach by presenting a prototype game in which players can adapt their system with recommended upgrades in order to progress through the game with improved tools, increased efficiency and enjoyment.

We introduce a location--based game called Feeding Yoshi that provides an example of seamful design, in which key characteristics of its underlying technologies-the coverage and security characteristics of WiFi-are exposed as a core element of gameplay. Feeding Yoshi is also a long--term, wide--area game, being played over a week between three different cities during an initial user study. The study, drawing on participant diaries and interviews, supported by observation and analysis of system logs, reveals players' reactions to the game. We see the different ways in which they embedded play into the patterns of their daily lives, augmenting existing practices and creating new ones, and observe the impact of varying location on both the ease and feel of play. We identify potential design extensions to Feeding Yoshi and conclude that seamful design provides a route to creating engaging experiences that are well adapted to their underlying technologies.

Social Proximity Applications (SPAs) are a promising new area for ubicomp software that exploits the everyday changes in the proximity of mobile users. While a number of applications facilitate simple file sharing between co–present users, this paper explores opportunities for recommending and sharing software between users. We describe an architecture that allows the recommendation of new system components from systems with similar histories of use. Software components and usage histories are exchanged between mobile users who are in proximity with each other. We apply this architecture in a mobile strategy game in which players adapt and upgrade their game using components from other players, progressing through the game through sharing tools and history. More broadly, we discuss the general application of this technique as well as the security and privacy challenges to such an approach.

This paper presents Treasure, an outdoor mobile multiplayer game inspired by Weiser's notion of seams, gaps and breaks in different media. Playing Treasure involves movement in and out of a wi-fi network, using PDAs to pick up virtual 'coins' that may be scattered outside network coverage. Coins have to be uploaded to a server to gain game points, and players can collaborate with teammates to double the points given for an upload. Players can also steal coins from opponents. As they move around, players' PDAs sample network signal strength and update coverage maps. Reporting on a study of players taking part in multiple games, we discuss how their tactics and strategies developed as their experience grew with successive games. We suggest that meaningful play arises in just this way, and that repeated play is vital when evaluating such games.

Outdoor multi-player games are an increasingly popular application area for ubiquitous computing, supporting experimentation both with new technologies and new user experiences. This paper presents an outdoor ubicomp game that exploits the gaps or seams that exist in complex computer systems. Treasure is designed so that players move in and out of areas of wireless network coverage, taking advantage not only of the connectivity within a wireless 'hotspot' but of the lack of connectivity outside it. More broadly, this paper discusses how the notion of seamful design can be a source of design ideas for ubicomp games.

Outdoor multi-player games are an increasingly popular application area for pervasive computing, supporting experimentation both with new technologies and new user experiences. This paper presents a set of experiments with an outdoor pervasive game that exploits the gaps or seams that exist in complex computer systems. The Bill game is designed so that players move in and out of areas of wireless network coverage, taking advantage of the connectivity within a wireless ‘hotspot’ and also of the lack of connectivity outside it. We draw lessons for how such games can successfully encourage social interaction between players, discuss the interaction between the game and the local environment, and describe our approach to recording and ‘replaying’ such games. More broadly, this paper discusses how the notion of seamful design can be a source of design ideas for such games.

Sharing events with others is an important part of many enjoyable experiences. While most existing co-presence systems focus on work tasks, in this paper we describe a lightweight mobile system designed for sharing leisure. This system allows city visitors to share their experiences with others both far and near, through tablet computers which share photographs, voice and locations. A collaborative filtering algorithm uses historical data of previous visits to recommend photos, web pages and places to visitors. In an extensive user trial we explored how these resources were used to collaborate around a physical place.

Sharing events with others is an important part of many enjoyable experiences. While most existing co-presence systems focus on work tasks, in this paper we describe a lightweight mobile system designed for sharing leisure. This system allows city visitors to share their experiences with others both far and near, through tablet computers that share photographs, voice and location. A collaborative filtering algorithm uses historical data of previous visits to recommend photos, web pages and places to visitors, bringing together online media with the city's streets. In an extensive user trial we explored how these resources were used to collaborate around physical places. The trial demonstrates the value of technological support for sociability - enjoyable shared social interaction. Lastly, the paper discusses support for collaborative photography, and the role history can play to integrate online media with physical places.

Video games are of increasing importance, both as a cultural phenomenon and as an application of collaborative technology. In particular, many recent online games feature persistent collaborative virtual environments (CVEs), with complex social organisation and strong social bonds between players. This paper presents a study of 'There', one such game, focusing on how There has been appropriated by its players. In particular we describe how its flexibility has allowed players to develop their own forms of play within the game. Three aspects of There are discussed: first, how the environment supports a range of social activities around objects. Second, how the chat environment is used to produce overlapping chat and how the game itself provides topics for conversation. Lastly, how the 'place' of There is a fluid interaction space that supports safe interactions between strangers. The paper concludes by drawing design lessons concerning the importance of supporting shared online activity, interaction between strangers, and the difficulties of designing for play.

The bandwidth of commonly available broadband connections is growing less quickly than the capacity of commonly available storage devices. UK broadband speeds for the home are commonly 512kbps for downloading and 256kbps for uploading, while the Apple iPod can hold 40 GB of data and the home PC often has a 120 GB hard drive. Downloading a 1GB file to a domestic PC may take a day. In contrast, short–range wireless networking technologies are improving dramatically. In the last year or so we have seen 802.11 speeds increase from 11mbits/s to 54mbits/s, and access points are appearing that can transfer at 108mbit/s. Transferring a 1GB file over wireless takes as little as 3 minutes in such conditions. These figures point towards a near future in which high bandwidth peer–to–peer short–range wireless connections are just as commonly used as the Internet. In addition, P2P ad hoc networks may alleviate some of the real world deployment issues of communications systems. The publicity about ‘wi–fi hotspots’ tends to distract attention from the large and cold expanses between such hotspots, i.e. the large areas with little network coverage. Even less is said of the way that the cost of commercial 802.11 access is a significant constraint on the use of hotspots. Since many everyday applications are built on the assumption of constant network access, they tend to perform poorly, or not at all, on mobile devices that are actually mobile. Ad hoc networks present difficulties in terms of transience and security, but they do support many interesting research avenues in the areas of mobile systems and ubiquitous computing. Applications that have no reliance on central servers, or only intermittent or indirect reliance on such servers, are capable of running at any location without requiring an active Internet connection, a connection to a particular access point or having a specific, static IP address.