Changing Places

By allowing any social institution to structure activity in any place, wireless information services break down the traditional mapping between institutions and places. This phenomenon greatly complicates the analysis of context for purposes of designing context-aware computing systems. Context has a physical, architectural aspect, but most aspects of context will also be defined in institutional terms. This paper develops two conceptual frameworks for the analysis of context in mobile and ubiquitous computing. The first framework concerns the relationship between architecture, practices, and institutions; it directs attention to the complex middle ground in which information services make use of whatever computational resources happen to be in the user's physical surroundings. The second framework is called the capture model; it rationally reconstructs the traditional systems analysis methods, which reorganize work activities to enable a computer to capture the information it needs. Context-aware computing devices that depart from the capture model face a difficult set of design trade-offs.