Gregory D. Abowd

Towards a Better Understanding of Context and Context-Awareness

When humans talk with humans, they are able to use implicit situational information, or context, to increase the conversational bandwidth. Unfortunately, this ability to convey ideas does not transfer well to humans interacting with computers. In traditional interactive computing, users have an impoverished mechanism for providing input to computers. By improving the computer’s access to context, we increase the richness of communication in human-computer interaction and make it possible to produce more useful computational services. The use of context is increasingly important in the fields of handheld and ubiquitous computing, where the user?s context is changing rapidly. In this panel, we want to discuss some of the research challenges in understanding context and in developing context-aware applications.

A conceptual framework and a toolkit for supporting the rapid prototyping of context-aware applications

Computing devices and applications are now used beyond the desktop, in diverse environments, and this trend toward ubiquitous computing is accelerating. One challenge that remains in this emerging research field is the ability to enhance the behavior of any application by informing it of the context of its use. By context, we refer to any information that characterizes a situation related to the interaction between humans, applications, and the surrounding environment. Context-aware applications promise richer and easier interaction, but the current state of research in this field is still far removed from that vision. This is due to 3 main problems: (a) the notion of context is still ill defined, (b) there is a lack of conceptual models and methods to help drive the design of context-aware applications, and (c) no tools are available to jump-start the development of context-aware applications. In this anchor article, we address these 3 problems in turn. We first define context, identify categories of contextual information, and characterize context-aware application behavior. Though the full impact of context-aware computing requires understanding very subtle and high-level notions of context, we are focusing our efforts on the pieces of context that can be inferred automatically from sensors in a physical environment. We then present a conceptual framework that separates the acquisition and representation of context from the delivery and reaction to context by a context-aware application. We have built a toolkit, the Context Toolkit, that instantiates this conceptual framework and supports the rapid development of a rich space of context-aware applications. We illustrate the usefulness of the conceptual framework by describing a number of context-aware applications that have been prototyped using the Context Toolkit. We also demonstrate how such a framework can support the investigation of important research challenges in the area of context-aware computing.

Cyberguide: a mobile context-aware tour guide

Future computing environments will free the user from the constraints of the desktop. Applications for a mobile environment should take advantage of contextual information, such as position, to offer greater services to the user. In this paper, we present the Cyberguide project, in which we are building prototypes of a mobile context‐aware tour guide. Knowledge of the users current location, as well as a history of past locations, are used to provide more of the kind of services that we come to expect from a real tour guide. We describe the architecture and features of a variety of Cyberguide prototypes developed for indoor and outdoor use on a number of different hand‐held platforms. We also discuss the general research issues that have emerged in our context‐aware applications development in a mobile environment.

Charting past, present, and future research in ubiquitous computing

The proliferation of computing into the physical world promises more than the ubiquitous availability of computing infrastructure; it suggest new paradigms of interaction inspired by constant access to information and computational capabilities. For the past decade, application-driven research on abiquitous computing (ubicomp) has pushed three interaction themes:natural interfaces, context-aware applications,andautomated capture and access. To chart a course for future research in ubiquitous computing, we review the accomplishments of these efforts and point to remaining research challenges. Research in ubiquitious computing implicitly requires addressing some notion of scale, whether in the number and type of devices, the physical space of distributed computing, or the number of people using a system. We posit a new area of applications research, everyday computing, focussed on scaling interaction with respect to time. Just as pushing the availiability of computing away from the traditional desktop fundamentally changes the relationship between humans and computers, providing continuous interaction moves computing from a localized tool to a constant companion. Designing for continous interaction requires addressing interruption and reumption of intreaction, representing passages of time and providing associative storage models. Inherent in all of these interaction themes are difficult issues in the social implications of ubiquitous computing and the challenges of evaluating> ubiquitious computing research. Although cumulative experience points to lessons in privacy, security, visibility, and control, there are no simple guidelines for steering research efforts. Akin to any efforts involving new technologies, evaluation strategies form a spectrum from technology feasibility efforts to long-term use studies—but a user-centric perspective is always possible and necessary

The context toolkit: aiding the development of context-enabled applications

Context-enabled applications are just emerging and promisericher interaction by taking environmental context into account.However, they are difficult to build due to their distributednature and the use of unconventional sensors. The concepts oftoolkits and widget libraries in graphical user interfaces has beentremendously successtil, allowing programmers to leverage offexisting building blocks to build interactive systems more easily.We introduce the concept of context widgets that mediate betweenthe environment and the application in the same way graphicalwidgets mediate between the user and the application. We illustratethe concept of context widgets with the beginnings of a widgetlibrary we have developed for sensing presence, identity andactivity of people and things. We assess the success of ourapproach with two example context-enabled applications we havebuilt and an existing application to which we have addedcontext-sensing capabilities.

The Aware Home: A Living Laboratory for Ubiquitous Computing Research

We are building a home, called the Aware Home, to create a living laboratory for research in ubiquitous computing for everyday activities. This paper introduces the Aware Home project and outlines some of our technology-and human-centered research objectives in creating the Aware Home.

The smart floor: a mechanism for natural user identification and tracking

We have created a system for identifying people based on their footstep force profiles and have tested its accuracy against a large pool of footstep data. This floor system may be used to identify users transparently in their everyday living and working environments. We have created user footstep models based on footstep profile features and have been able to achieve a recognition rate of 93%. We have also shown that the effect of footwear is negligible on recognition accuracy.

Classroom 2000: an experiment with the instrumentation of a living educational environment

One potentially useful feature of future computing environments will be the ability to capture the live experiences of the occupants and to provide that record to users for later access and review. Over the last three years, a group at the Georgia Institute of Technology has designed and extensively used a particular instrumented environment: a classroom that captures the traditional lecture experience. This paper describes the history of the Classroom 2000 project and provides results of extended evaluations of the effect of automated capture on the teaching and learning experience. There are many important lessons to take away from this long-term, large-scale experiment with a living, ubiquitous computing environment. The environment should address issues of scale and extensibility, it should continuously be evaluated for effectiveness, and the ways in which the environment both improves and hinders the activity that it aims to support—in our case, education—need to be understood and acted upon. In d escribing our experiences and lessons learned, we hope to motivate other researchers to take more seriously the challenge of ubiquitous computing—the creation and exploration of the everyday use of computationally rich environments.

SAAM: a method for analyzing the properties of software architectures

While software architecture has become an increasingly important research topic in recent years, insufficient attention has been paid to methods for evaluation of these architectures. Evaluating architectures is difficult for two main reasons. First, there is no common language used to describe different architectures. Second, there is no clear way of understanding an architecture with respect to an organizations life cycle concerns -software quality concerns such as maintainability portability, modularity, reusability, and so forth. We address these shortcomings by describing three perspectives by which we can understand the description of a software architecture and then proposing a five-step method for analyzing software architectures called SAAM (Software Architecture Analysis Method). We illustrate the method by analyzing three separate user interface architectures with respect to the quality of modifiability.<<ETX>>

Scenario-based analysis of software architecture

Despite advances in clarifying high level design needs, analyzing a systems ability to meet desired quality criteria is still difficult. The authors propose using scenarios to make analysis more straightforward. In their case study report, they analyze lessons learned with this approach. They developed the Software Architecture Analysis Method, an approach that uses scenarios to gain information about a systems ability to meet desired quality attributes. Scenarios are brief narratives of expected or anticipated system uses from both user and developer views and they provide a look at how the system satisfies quality attributes in various use contexts.