Toward context-aware computing: experiences and lessons

Abstract

T he effects of Moore's law are apparent everywhere: Chip density, processor speed, memory cost, disk capacity, and network bandwidth are improving relentlessly. As computing costs plummet, a resource that we have ignored until now becomes the limiting factor in computer systems-user attention, namely a person's ability to focus on his or her primary task.Distractions occur especially in mobile environments, because walking, driving, or other real-world interactions often preoccupy the user. A pervasivecomputing environment that minimizes distraction must be context aware, and a pervasive-computing system must know the user's state to accommodate his or her needs.Context-aware applications provide at least two fundamental services: spatial awareness and temporal awareness. Spatially aware applications consider a user's relative and absolute position and orientation. Temporally aware applications consider the time schedules of public and private events. With an interdisciplinary class of Carnegie Mellon University (CMU) students, we developed and implemented a context-aware, pervasive-computing environment that minimizes distraction and facilitates collaborative design. Our approachTo identify the types of distraction that occur during the design process, we created an activity-attention matrix-the Distraction Matrix (see Figure 1). The Distraction Matrix categorizes activities as information (active and passive), communication (artificial, formal, and informal), and creation (contribution). Subcategories specify the types of primary activity within each category. For example, receiving information is a type of active-information activity, and initiating communication is a type of artificialcommunication activity.We based each distraction's location on how long it interrupts a primary activity. We categorized interruption durations as snap, pause, tangent, and extended. A snap distraction is one you usually complete in a few seconds, such as checking your watch; it should not interrupt your primary activity. A pause distraction involves stopping the primary activity, switching to a related one, and then switching back within a few minutes. Pulling over to the side of the road and checking directions is an example. A tangent distraction, such as receiving an unrelated phone call, is of medium duration and is unrelated to your primary activity. An extended distraction, such as stopping at a motel and resting for the night, is a relatively long-term interruption of your primary activity. ApplicationsWe equipped the campus with 400 wireless-networking access points, enabling wireless coverage for the entire campus. To move distractions toward the Distraction Matrix's left (snap) side, we implemented a complementary set of interactive applications and services that support mobile team-design activities. (See the related sidebar for information on relevant work in context-aware computing.) Portable Help Desk. Because they have many meetings at various times and locations, students are often To minimize distractions, a p...

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