Cross-platform functionality in practice : exploring the influence of system composition on user experiences of personal exercise monitoring

Cross-platform configurations—systems and services employing multiple devices and applications in concert—increasingly penetrate a variety of personal and recreational domains, such as entertainment, photography and physical exercise. Supporting regular physical exercise is important in reducing health threats such as obesity and heart disease. Many personal exercise monitoring solutions employ a cross-platform configuration. This work is positioned at the intersection of two streams of research: 1) cross-platform systems and 2) technology-mediated physical exercise. The key question is: How does composition—the manner by which roles, functionality and content are allocated across system components—influence use and user experience. This thesis investigates how composition works and functionality and content may be allocated efficiently. This work takes on a qualitative case study approach, featuring a heart rate monitoring system comprising a wearable heart rate monitor and a web service. The findings reveal that the composition of cross-platform systems essentially influences user experiences. Cross-platform systems may support different ways of carrying out activities through role-based and modular organization of components. Complementary allocation of functionality may reduce the complexity on individual devices and increase components’ fit for purpose. Several challenges in combinatorial use, such as the limited functionality of specific devices or the redundancy of functionality, could be overcome by strategic allocation. Despite the challenges, cross-platform systems may effectively support cross-contextual activities. In exercise monitoring, the role of the interactive mobile device was particularly central for motivation, learning and controlling target behavior. Conventional exercise diaries or non-interactive solutions based on sensors may benefit from the inclusion of “runtime” interactivity. This study identifies composition as a designable characteristic of cross-platform systems constituted by structure of roles, distribution of functionality and content and functional modularity. This conceptualization proposes new directions for the study and design of crossplatform systems. The thesis discusses ways to allocate roles effectively. It also suggests guidelines for cross-platform composition.