Showing papers by "Hans Gellersen published in 2008"
19 Sep 2008
TL;DR: Simulation results show that satisfactory guidance performance is achieved despite noisy ultrasound measurements, magnetic interference and uncertainty in ultrasound node locations, and the inherent drift observed in dead reckoning is addressed by deploying ultrasound beacons as landmarks.
Abstract: Ad hoc solutions for tracking and providing navigation support to emergency response teams is an important and safety-critical challenge. We propose a navigation system based on a combination of foot-mounted inertial sensors and ultrasound beacons. We evaluate experimentally the performance of our dead reckoning system in different environments and for different trail topologies. The inherent drift observed in dead reckoning is addressed by deploying ultrasound beacons as landmarks. We study through simulations the use of the proposed approach in guiding a person along a defined path.Simulation results show that satisfactory guidance performance is achieved despite noisy ultrasound measurements, magnetic interference and uncertainty in ultrasound node locations. The models used for the simulations are based on experimental data and the authors' experience with actual sensors. The simulation results will be used to inform future development of a full real time system.
117 citations
18 Feb 2008
TL;DR: VoodooSketch is a system that extends interactive surfaces with physical interface palettes on which users can dynamically deploy controls as shortcut to application functionality.
Abstract: VoodooSketch is a system that extends interactive surfaces with physical interface palettes on which users can dynamically deploy controls as shortcut to application functionality. The system provides physical 'plug and play' controls as well as support for sketching of controls, and allows controls to be associated with application functions via handwritten labels. The system uses a special digital pen, which writes 'real' ink on the palettes while functioning as a digital input device on the interactive surfaces. The palettes can be seamlessly integrated into existing applications, be appropriated by the user to suit different input requirements, and support new interaction styles across multiple surfaces, palettes and users.
38 citations
TL;DR: Three different authentication methods for device-to-device authentication based on sensor data from various physical out-of-band channels are described: shaking devices together, authentication basedon spatial reference, and transmission via visible laser.
19 citations
28 Oct 2008
TL;DR: The main findings of the study are: that users are able to easily create sketched controls; that they can use them as effectively as traditional input devices; that handwritten labelling is more efficient for control mapping than conventional screen-based methods; and that the sketches improve user performance and reduce error rates.
Abstract: An advantage of physical interfaces over graphical widgets is that they bring controls closer to hand. VoodooSketch is a system that supports dynamic customisation of tabletop interfaces with physical controls that users can arrange on palettes. The system employs pen and paper techniques to achieve two novel capabilities: first, users are able to sketch controls that are immediately operational for pen interaction; second, users can label the controls with a handwritten name that identifies their function and binds the control to an application. This paper presents the results of an empirical evaluation of the VoodooSketch interface customisation techniques. The main findings of the study are: that users are able to easily create sketched controls; that they can use them as effectively as traditional input devices; that handwritten labelling is more efficient for control mapping than conventional screen-based methods; and that the sketched controls improve user performance and reduce error rates.
11 citations
02 Sep 2008
TL;DR: The results show an overall user preference for the iconic map over the spatial and alphabetical list, however, there was no clear preferences for the spatial interfaces over the non-spatial condition with respect to user satisfaction and mental load.
Abstract: Use of spatial information to support discovery of interaction opportunities has been widely demonstrated. In this paper, we focus on the use of spatial interfaces for identification and selection of devices a mobile user encounters in their immediate environment. We contribute an experimental evaluation of two spatial interface conditions in comparison with a non-spatial condition. The two spatial interface conditions are a device list ordered by distance and an iconic map of devices as seen from the user's perspective and the non-spatial condition is an alphabetical list. Our results show an overall user preference for the iconic map over the spatial and alphabetical list. However, there was no clear preference for the spatial interfaces over the non-spatial condition with respect to user satisfaction and mental load.
7 citations
05 Apr 2008
TL;DR: It is shown that mobile phone & screen has a better performance than phone only and some interaction issues when using a mobile phone with a large screen are discussed.
Abstract: In this paper we compare performance and usability between three different device combinations: a) mobile phone b) touch screen c) mobile phone & screen. We show that mobile phone & screen has a better performance than phone only. We also discuss some interaction issues when using a mobile phone with a large screen.
7 citations
29 Oct 2008
TL;DR: It is found that the training of appearance descriptions must coincide with the scale and orientations providing the best detection performance, that multiple cues provide a clear performance gain over a single cue and that context sensing masks distractions and clutter, further improving detection performance.
Abstract: We evaluate an approach for mobile smart objects to cooperate with projector-camera systems to achieve interactive projected displays on their surfaces without changing their appearance or function. Smart objects describe their appearance directly to the projector-camera system, enabling vision-based detection based on their natural appearance. This detection is a significant challenge, as objects differ in appearance and appear at varying distances and orientations with respect to a tracking camera. We investigate four detection approaches representing different appearance cues and contribute three experimental studies analysing the impact on detection performance, firstly of scale and rotation, secondly the combination of multiple appearance cues and thirdly the use of context information from the smart object. We find that the training of appearance descriptions must coincide with the scale and orientations providing the best detection performance, that multiple cues provide a clear performance gain over a single cue and that context sensing masks distractions and clutter, further improving detection performance.
6 citations
18 Feb 2008
TL;DR: A system that extends a typical workstation environment with a malleable physical interface for working with digital clips that allows users to pick digital clips, give each its own dedicated key for direct access, and combine keys dynamically on a physical surface in a way that inherently reflects the state of an extended clipboard.
Abstract: We present a system that extends a typical workstation environment with a malleable physical interface for working with digital clips. It allows users to pick digital clips, give each its own dedicated key for direct access, and combine keys dynamically on a physical surface in a way that inherently reflects the state of an extended clipboard. The system affords copying and pasting of multiple clips each directly accessible through its own key shortcut. The keys can also be dynamically re-arranged to organize clips, and taken from workstation to another to transport clips, acting simultaneously as token and as copy-paste-interface for a digital object.
6 citations