The original vision of ubiquitous computing [14] is about enabling people to more easily accomplish tasks through the seamless interworking of the physical environment and a computing infrastructure. A major challenge to the practical realization of this vision involves the integration of commercial-o-the-shelf (COTS) hardware and software components: consider the awkwardness of such a mundane task as exporting a textual memo written on a Palm Pilot to a Microsoft Word document. It is not enough to overcome the protocol and data format mismatches that currently impede the interoperation of these entities: for the user experience to be truly seamless, we must provide a framework for the dynamic connection of such endpoints on demand, to support the ad-hoc interactions that are an integral part of ubiquitous computing. To this end, we oer a dynamic mediation framework called Paths. A Path consists of dynamically instantiated, automatically composable operators that brid...

This paper motivates and details a document-based framework for manipulating the components that comprise distributed Internet applications. In the framework, XML documents are used to describe both server-side functionality and the mapping between a client's applications and the servers it accesses. Our system model contrasts with explicitly context-aware application designs, where location information must be explicitly manipulated by the application to affect change; instead, a middleware layer is interposed between client applications and services so that invocations between the two can be transparently remapped. This approach is useful for a subset of application domains, including our example domain of "remote control" of local resources (e.g., lights, stereo components, etc.). We illustrate how the framework allows for 1) remapping of a portion of an existing user interface to a new service, 2) viewing of arbitrary subsets and combinations of the available functionality, and 3) ...

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

The common mode of interaction with a computer involves a single user using a mouse and keyboard in front of a single display. With the proliferation of mobile devices and the ability to embed large touch screens in workrooms, a new type of human computer interaction involving multiple machines and multiple people becomes possible. This research looks at the case of ubiquitous computing rooms, or interactive workspaces. These are device rich spaces where groups come together to collaborate on solving some problem. The nature of interaction in such a space will be with collections (or ensembles) of applications, and to date there is no clear model of how these applications should coordinate with one another at the application level. This dissertation addresses the need for a well-suited middleware infrastructure for application coordination in interactive workspaces. It consists of three main contributions. The first is a characterization of interactive workspaces and the requirements for a coordination infrastructure for such space. The second is the Event Heap coordination model, which is an extended version of the tuplespace model. It consists of a set of properties, of which the most key is decoupling

As computers and large displays become cheaper, additional modes of human computer interaction are becoming possible. One can now set up an interactive workspace in which multiple computer displays and input devices are simultaneously visible and usable by one or more users. Unfortunately, the well-known event queue metaphor, which works well for a single user sitting in front of a single computer using a GUI, breaks down in such an interactive workspace. We propose the Event Heap as a novel mechanism by which multiple users, machines and applications can all simultaneously interact as consumers and generators of system events. The Event Heap is flexible, robust to failure of individual interactors, and sufficiently lightweight to be integrated easily with “legacy ” single-user-GUI applications.

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For many years, people have been trying to develop systems from modular, reusable components. The ideal goal is zero-code composition: building an application out of existing components without having to write code. Today's component frameworks are built under the assumption that the same methods used to construct components should also be used to compose them; but these methods actually impede compositional reuse. We identify two main classes of these impediments: those having to do with control ow within a composition, and those having to do with how components interface with each other. We propose solutions for removing these impediments. We also introduce preliminary results showing how some software engineering techniques used to build large systems are made more compelling within this zero-code composition framework.

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anonymous information storage and retrieval system, ” in Proc. Workshop

anonymous information storage and retrieval system, ” in Proc. Workshop