extension of a project to investigate interaction with large high resolution displays. It was initially set up in a busy laboratory where the device proved to be no more than a curiosity, since it could not be practically used for long periods of time and offered little integration with other

. In this paper, we propose ICrafter, a framework for services

We describe the design of and experience with PointRight, a peerto-peer pointer and keyboard redirection system that operates in multi-machine, multi-user environments. Point-Right employs a geometric model for redirecting input across screens driven by multiple independent machines and operating systems. It was created for interactive workspaces that include large, shared displays and individual laptops, but is a general tool that supports many different configurations and modes of use. Although previous systems have provided for re-routing pointer and keyboard control, in this paper we present a more general and flexible system, along with an analysis of the types of re-binding that must be handled by any pointer redirection system This paper describes the system, the ways in which it has been used, and the lessons that have been learned from its use over the last two years.

The iStuff toolkit of physical devices, and the flexible software infrastructure to support it, were designed to simplify the exploration of novel interaction techniques in the post-desktop era of multiple users, devices, systems and applications collaborating in an interactive environment. The toolkit leverages an existing interactive workspace infrastructure, making it lightweight and platform independent. The supporting software framework includes a dynamically configurable intermediary to simplify the mapping of devices to applications. We describe the iStuff architecture and provide several examples of iStuff, organized into a design space of ubiquitous computing interaction components. The main contribution is a physical toolkit for distributed, heterogeneous environments with run-time retargetable device data flow. We conclude with some insights and experiences derived from using this toolkit and framework to prototype experimental interaction techniques for ubiquitous computing environments.

Pervasive and mobile computing call for suitable middleware and programming models to support the activities of complex software systems in dynamic network environments. In this paper we present TOTA (“Tuples On The Air”), a novel middleware and programming approach for supporting adaptive context-aware activities in pervasive and mobile computing scenarios. The key idea in TOTA is to rely on spatially distributed tuples, adaptively propagated across a network on the basis of application-specific rules, for both representing contextual information and supporting uncoupled interactions between application components. TOTA promotes a simple way of programming that facilitates access to distributed information, navigation in complex environments, and achievement of complex coordination tasks in a fully distributed and adaptive way, mostly freeing programmers and system managers form the need to take care of lowlevel issues related to network dynamics. This paper includes both application examples to clarify concepts and performance figures to show the feasibility of the approach.

This research explores distributed sensing techniques for mobile devices using synchronous gestures. These are patterns of activity, contributed by multiple users (or one user with multiple devices), which take on a new meaning when they occur together in time, or in a specific sequence in time. To explore this new area of inquiry, this work uses tablet computers augmented with touch sensors and twoaxis linear accelerometers (tilt sensors). The devices are connected via an 802.11 wireless network and synchronize their time-stamped sensor data. This paper describes a few practical examples of interaction techniques using synchronous gestures such as dynamically tiling together displays by physically bumping them together, discusses implementation issues, and speculates on further possibilities for synchronous gestures.

In this paper we motivate a Context Fusion Network (CFN), an infrastructure model that allows contextaware applications to select distributed data sources and compose them with customized data-fusion operators into a directed acyclic information fusion graph. Such a graph represents how an application computes high-level understandings of its execution context from low-level sensory data. Multiple graphs by different applications inter-connect with each other to form a global graph. A key advantage of a CFN is re-usability, both at code-level and instance-level, facilitated by operator composition. We designed and implemented a distributed CFN system, Solar, which maps the logical operator graph representation onto a set of overlay hosts. In particular, Solar meets the challenges inherent to heterogeneous and volatile ubicomp environments. By abstracting most complexities into the infrastructure, Solar facilitates both the development and deployment of context-aware applications. We present the operator composition model, basic services of the Solar overlay network, and programming support for the developers. We also discuss some applications built with Solar and the lessons we learned from our experience. 1

Abstract. The current interest in programming models and software infrastructures to support ubiquitous and environmental computing is heightened by the falling cost of hardware and the ubiquity of local-area wireless networking technologies. Interactive workspaces are technologically augmented team-project rooms that represent a specific sub-domain of ubiquitous computing. We argue both from related work and from our own experience with a prototype that the tuplespace model of communication forms the best basis for a coordination infrastructure for such workspaces. This paper presents the usage and characteristics expected of interactive workspaces, from which we derive a set of key system properties for any coordination infrastructure in an interactive workspace. We show that the design aspects of tuplespaces, augmented with some new extensions, yield a system model, which we call the Event Heap, that satisfies all of the desired properties. We also briefly discuss why other coordination models fall short of the desired properties, and describe our experience using our implementation of the Event Heap model. The paper focuses on a justification of the use of tuplespaces in interactive workspaces, and does not provide a detailed discussion of the Event Heap implementation or our more general experience with interactive workspaces, each of which is treated in detail elsewhere. 1

Abstract. Location is a primary cue in many context-aware computing systems, and is often represented as a global coordinate, room number, or a set of Euclidean distances to various landmarks. A user’s concept of location, however, is often defined in terms of regions in which similar activities occur. We discuss the concept of such regions, which we call activity zones, and suggest that such zones can be used to trigger application actions, retrieve information based on previous context, and present information to users. We show how to semi-automatically partition a space into activity zones based on patterns of observed user location and motion. We describe our system and two implemented example applications whose behavior is controlled by users ’ entry, exit, and presence in the zones. 1

In this paper, a conceptual model for synchronous applications in ubiquitous computing environments is proposed. To test its applicability, it was used to structure the architecture of the BEACH software framework that is the basis for the software infrastructure of i-LAND (the ubiquitous computing environment at FhG-IPSI). The BEACH framework provides the functionality for synchronous cooperation and interaction with roomware components, i.e. room elements with integrated information technology. To show how the BEACH model and framework can be applied, the design of a sample application is explained. Also, the BEACH model is positioned against related work. In conclusion, we provide our experiences with the current implementation.