Rafael Ballagas

iStuff: a physical user interface toolkit for ubiquitous computing environments

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 in-frastructure, 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.

Spontaneous marriages of mobile devices and interactive spaces

Configuring themselves through Elope middleware, tagged physical objects and rooms let users seamlessly integrate their content and invoke services.

iStuff mobile: rapidly prototyping new mobile phone interfaces for ubiquitous computing

iStuff Mobile is the first rapid prototyping framework that helps explore new sensor-based interfaces with existing mobile phones. It focuses on sensor-enhanced physical interfaces for ubiquitous computing scenarios. The framework includes sensor network platforms, mobile phone software, and a proven rapid prototyping framework. Interaction designers can use iStuff Mobile to quickly create and test functional prototypes of novel interfaces without making internal hardware or software modifications to the handset. A visual programming paradigm provides a low threshold for prototyping activities: the system is not difficult to learn. At the same time, the range of examples built using the toolkit demonstrates a high ceiling for prototyping activities: the toolkit places few limits on prototype complexity. A user study shows that the visual programming metaphor enables prototypes to be built faster and encourages more iterations than a previous approach.

Patch panel: enabling control-flow interoperability in ubicomp environments

Ubiquitous computing environments accrete slowly over time rather than springing into existence all at once. Mechanisms are needed for incremental integration- the problem of how to incrementally add or modify behaviors in existing ubicomp environments. Examples include adding new input modalities and choreographing the behavior of existing independent applications. The iROS event heap, via its publish-subscribe coordination mechanism, provides the foundation for interoperation through event intermediation, but does not directly provide facilities for expressing these intermediations. The patch panel provides a general facility for retargeting event flow. Intermediations can be expressed as simple event translation mappings or as more complex finite-state machines. We describe an implemented prototype of the patch panel, including examples of its use drawn from real life applications in production use in the iRoom ubiquitous computing environment.

UbiComp 2006 Workshops, Part 1

This article presents summaries of four of the UbiComp 2006 Workshops: Interactive Media Systems for Seniors, Exurban Noir, Personalized Context Modeling and Management for UbiComp Applications, and System Support for Future Mobile Computing Applications. The other summaries will appear in the April-June 2007 issue.

VR Grabbers: Ungrounded Haptic Retargeting for Precision Grabbing Tools

Haptic feedback in VR is important for realistic simulation in virtual reality. However, recreating the haptic experience for hand tools in VR traditionally requires hardware with precise actuators, adding complexity to the system. We propose Ungrounded Haptic Retargeting, an interaction technique that provides a realistic haptic experience for grabbing tools using only passive mechanisms. This technique leverages the ungrounded feedback inherent in grabbing tools combined with dynamic visual adjustments of their position in virtual reality to create an illusion of physical presence for virtual objects. To demonstrate the capabilities of this technique, we created VR Grabbers, an exemplary passive VR controller, similar to training chopsticks, with haptic feedback for precise object selection and manipulation. We conducted two user studies based on VR Grabbers. The first study probed the perceptual limits of the illusion; we found that the maximum position difference between the virtual and physical world acceptable to the user is (-1.48, 1.95) cm. The second study showed that task performance of the VR Grabbers controller with Ungrounded Haptic Retargeting enabled outperforms the same controller with Ungrounded Haptic Retargeting disabled.