Abstract. The use of context is important in interactive applications. It is particularly important for applications where the user’s context is changing rapidly, such as in both handheld and ubiquitous computing. In order to better understand how we can use context and facilitate the building of context-aware applications, we need to more fully understand what constitutes a contextaware application and what context is. Towards this goal, we have surveyed existing work in context-aware computing. In this paper, we provide an overview of the results of this survey and, in particular, definitions and categories of context and context-aware. We conclude with recommendations for how this better understanding of context inform a framework for the development of context-aware applications. 1

Configuration of the computing and communications systems found at home and in the workplace is a complex task that currently requires the attention of the user. Recently, researchers have begun to examine computers that would autonomously change their functionality based on observations of who or what was around them. By determining their context, using input from sensor systems distributed throughout the environment, computing devices could personalize themselves to their current user, adapt their behavior according to their location, or react to their surroundings. The authors present a novel sensor system, suitable for large-scale deployment in indoor environments, which allows the locations of people and equipment to be accurately determined. We also describe some of the context-aware applications that might make use of this fine-grained location information.

The PARCTAB is a personal digital assistant (PDA) that communicates via infrared (IR) data-packets to a network of IR transceivers. The infrared network is designed for in-building use, where each room becomes a communication cell. In contrast to the approach used by other PDAs, most PARCTAB applications run on remote hosts and therefore depend on reliable communication through the IR network. The infrastructure provides reliability as well as uninterrupted service when a PARCTAB moves from cell to cell. The PARCTAB and a supporting infrastructure [1, 4] has been operational since March 1993 at the Computer Science Lab at Xerox PARC. The system currently comprises thirty cells and twenty-five PARCTABs and will expand in the near future. There are three types of software components in the PARCT

Environmental factors affecting shared spaces are typically designed to appeal to the broadest audiences they are expected to serve, ignoring the preferences of the people actually inhabiting the environment at any given time. Examples of such factors include the lighting, temperature, décor or music in the common areas of an office building. We have designed and deployed MUSICFX, a group preference arbitration system that allows the members of a fitness center to influence, but not directly control, the selection of music in a fitness center. We present a number of empirical results from our work with this intelligent environment: the results of a poll of fitness center members, a quantitative evaluation of the performance of a group preference arbitrator in a shared environment, and some interesting anecdotes about members’ experiences with the system.

This paper describes what we see as fundamental difficulties in both the pure ubiquitous computing and pure wearable computing paradigms when applied to context-aware applications. In particular, ubiquitous computing and smart room systems tend to have difficulties with privacy and personalization, while wearable systems have trouble with localized information, localized resource control, and resource management between multiple people. These difficulties are discussed, and a peer-to-peer network of wearable and ubiquitous computing components is proposed as a solution. This solution is demonstrated through several implemented applications.

this paper, we describe an architecture that supports the building of context-aware services that assume context is ambiguous and allows for mediation of ambiguity by mobile users in aware environments. We discuss design guidelines that arise from supporting mediation over space and time, issues not present in the graphical user interface domain, where mediation has typically been used in the past. We illustrate the use of our architecture and the design guidelines and evaluate it through three example context-aware services, a word predictor system, an In/Out Board, and a reminder tool

Todays, we assist to the explosive development of mobile computing devices li PDAs and cell-phones, thei)"fl grati n of embedded intellience (liN Webserver)i more and more common deviH:: and the proliU"H ti n of wireless communication technologies (IRdA, Bluetooth, IEEE 802.11, GPRS). All these trends contribute to move us closer to the ubiquitous computing world described by Mark Weiser. But while

Software design methods share many characteristics with design methods in other fields. All these methods are the progeny of philosophies of design that are in turn influenced by more general philosophic movements. This essay begins with the influence of philosophies of science on the study of design, highlighting the effects on design discourse of Cartesian rationality, the hypothetico-deductive account of scientific progress, and Kuhnian paradigms. Next, the influence of the constructivist and humanist movements on design thinking are considered, culminating in the introduction of a philosophy of design based on hermeneutics, or interpretation. The influence of design philosophy on software design methods begins a categorization of several software design methods according to the design theory framework, with some emphasis on design methods that support a hermeneutical style of design. Some justification for a pluralistic approach to software design methodology rounds out the essay. ...

Much of the research into intelligent environments has focused on how an environment might sense and respond to the presence and/or actions of a single individual in that environment. MUSICFX is a system that responds to the presence of a group of people in a shared environment by using a Group Preference Agent to select music that will best accommodate the musical preferences of that group.

The recent proliferation of portable computers, the advent of personal digital assistants (PDAs) and continuing advances in computer networking all point to a future in which mobility of both users and computing system elements will be standard. However, these developments also invalidate many of the assumptions made by current system software, which has been built for stationary systems and users. An important component of system software that needs to looked at afresh is the file system. A user should be able to access the files he or she needs regardless of location. Although existing research efforts do provide some support for this, there are significant deficiencies that need to be remedied. We propose two related designs to address these problems. The first exploits the unique property of a PDA that it can accompany its owner at all times by using it to carry files of most immediate need to him or her. The second makes use of the recently proposed idea of a computing persona. ...