Series
GVU Technical Report Series

Permanent Link
https://hdl.handle.net/1853/71001
Series Type
Publication Series
Description
Associated Organization(s)
Associated Organization(s)
Organizational Unit

Filters

2002 - 2006 145
145
145
145
Reset filters

Settings
End date: 2006 × Start date: 2002 × search.filters.applied.f.resourcesubtype: Technical Report ×

Publication Search Results

Now showing 1 - 10 of 145
Thumbnail Image
Item

Distributed Multi-AUV Coordination in Naval Mine Countermeasure Missions

2006 , Sariel, Sanem , Balch, Tucker , Stack, Jason

In this paper, we evaluate performance of our coordination framework, for Naval Mine Countermeasure (MCM) missions on the ALWSE-MC simulator. Our coordination framework integrates a distributed task allocation scheme, coor-dination mechanisms and precaution routines for multi robot team execution. Its performance has already been demonstrated in multi-robot TSP and object con-struction domains. Marine applications provide additional challenges such as noisy communication, position uncertainty and the likelihood of robot failures. There is a high probability that the initial assignments and considerations are sub-ject to change during run time in these kinds of environments. Our framework provides an auction based task allocation mechanism and uses its precaution rou-tines to ensure robust execution and effective completion of missions against sev-eral different types of failures. Preliminary results for MCM missions are promis-ing in the sense of mission completion, and AUV paths are close to optimal in the presence of uncertainties. In this work, we evaluate qualitative performance of our framework for handling different contingencies that may arise run time.

View
Thumbnail Image
Item

Reading on the Go: An Evaluation of Three Mobile Display Technologies

2006 , Vadas, Kristin , Lyons, Kenton Michael , Ashbrook, Daniel , Yi, Ji Soo , Starner, Thad , Jacko, Julie A.

As mobile technology becomes a more integral part of our everyday lives, understanding the impact of different displays on perceived ease of use and overall performance is becoming increasingly important. In this paper, we evaluate three mobile displays: the MicroOptical SV-3, the Sony Librie, and the OQO Model 01. These displays each use different underlying technologies and offer unique features which could impact mobile use. The OQO is a hand-held device that utilizes a traditional transflective liquid crystal display (LCD). The MicroOptical SV-3 is a head-mounted display that uses a miniature LCD and offers hands free use. Finally, the Librie uses a novel, low power reflective electronic ink technology. We present a controlled 15-participant evaluation to assess the effectiveness of using these displays for reading while in motion.

View
Thumbnail Image
Item

Advections with Significantly Reduced Dissipation and Diffusion

2006 , Kim, Byungmoon , Liu, Yingjie , Llamas, Ignacio , Rossignac, Jarek

Back and Forth Error Compensation and Correction (BFECC) can be applied to reduce dissipation and diffusion in advection steps, such as velocity, smoke density, and image advections. It can be implemented trivially as a small modification of the first-order upwind or semi-Lagrangian integration of advection equations. It provides second-order accuracy in both space and time and reduces volume loss significantly. We demonstrate its benefits on the simulation of smoke, bubbles, and interaction between water, a solid, and air.

View
Thumbnail Image
Item

Revisiting and Validating a Model of Two-Thumb Text Entry

2006 , Clarkson, Edward C. , Lyons, Kenton Michael , Clawson, James , Starner, Thad

MacKenzie and Soukoreff have previously introduced a Fitts' Law--based performance model of expert two--thumb text entry on mini--QWERTY keyboards. In this work we validate the original model and update it to account for observed behavior. We conclude by corroborating our updated version of the model with our empirical data. The result is a validated model of two-thumb text entry that can inform the design of mobile computing devices.

View
Thumbnail Image
Item

Simulation of Bubbles and Liquid Films

2006 , Kim, Byungmoon , Liu, Yingjie , Llamas, Ignacio , Rossignac, Jarek

Liquid and gas interactions often contain bubbles surrounded by thin liquid films. Simulation of these liquid films is challenging since they quickly become thinner than the grid resolution, which leads to premature bursting or merging of the bubbles. We prevent this thinning process by applying a disjoining force to the film, obtaining bubbles that last much longer without bursting or merging. The surface tension on the liquid film is the next diffuculty. Since the level set is not differentiable at the center of the thin liquid film, the curvature computed from the level set gradient is noisy, and the thin liquid film ruptures quickly. To prevent this, we compute the surface tension from the local isosurface, obtaining long-lasting liquid films. However, since bubbles stay longer without bursting or merging, the volume loss of each bubble is noticeable. To solve this problem, we modify the pressure projection to produce a velocity field whose divergence is controlled by the proportional and integral feedback. This allows us to preserve the volume or, if desired, to inflate or deflate the bubbles. In addition to premature bursting and volume change, another difficulty is the complicated liquid surface, which increases memory and computational costs. To reduce storage requirement, we collocate the velocity and pressure to simplify the octree mesh. To reduce the computational complexity of the pressure projection, we use a multigrid method.

View
Thumbnail Image
Item

Boundary of the Volume Swept By a Free-form Solid in Screw Motion

2006 , Rossignac, Jarek , Kim, J. J. , Song, S. C. , Suh, K. C. , Joung, C. B.

The swept volume of a moving solid provides an excellent aid for path and accessibility planning in robotics and for simulating various manufacturing operations. To compute the boundary of the swept volume, we approximate the motion by a polyscrew (continuous, piecewise-screw), generate candidate faces, compute the two-cells of their arrangement, and use a new point-in-sweep test to select the correct cells whose union forms the boundary of the swept volume.

View
Thumbnail Image
Item

Spectral Predictors

2006 , Lindstrom, Peter , Rossignac, Jarek , Ibarria, Lorenzo (Lawrence)

Many applications produce large high-precision scalar fields sampled on a regular grid. Lossless compression of such data is commonly done using predictive coding, in which weighted combinations of previously coded samples known to both encoder and decoder are used to predict subsequent nearby samples. In hierarchical, incremental, or selective transmission, the spatial pattern of the known neighbors is often irregular and varies from one sample to the next, which precludes prediction based on a single stencil and fixed set of weights. To make the best use of available neighboring samples, we propose a local spectral predictor that offers optimal prediction by tailoring the weights to each configuration of known nearby samples. We show that predictive coding using our spectral predictor improves compression for various sources of high-precision data.

View
Thumbnail Image
Item

Applying Heuristic Evaluation to Human-Robot Interaction Systems

2006 , Clarkson, Edward C. , Arkin, Ronald C.

Though attention to evaluating human-robot interfaces has increased in recent years, there are relatively few reports of using evaluation tools during the development of human-robot interaction (HRI) systems to gauge and improve their designs-possibly due to a shortage of suitable evaluation techniques. Heuristic evaluation is a technique suitable for such applications that has become popular in the human-computer interaction (HCI) community. However, it requires usability heuristics applicable to the system environment. This work contributes a set of heuristics appropriate for use with HRI systems, derived from a variety of sources both in and out of the HRI field. Evaluators have successfully used the heuristics on an HRI system, demonstrating their effectiveness against standard measures of heuristic effectiveness.

View
Thumbnail Image
Item

Framework for Comparative Research on Relational Information Displays

2006 , Park, Sung Jun , Catrambone, Richard

We identify critical issues in comparative research on relational information displays (RIDs). The key argument is that when conducting an analysis of the cognitive process of people viewing different displays, their perceptual processes must be held constant so that they do not affect the results. We propose that in order to help researchers more easily compare display types (e.g., graphs) for how effectively they convey information, two factors must be considered. First, each element (e.g., each bar in a bar graph) in graphs that are being compared has to be equally discriminable. Second, the number of elements in the graphs being compared has to be the same; the maximum number of elements is limited by from the graph that uses a presentation format (e.g., density) that has the fewest number of discriminable levels. We present a psychophysics experiment that identified differential discrimination thresholds for density levels.

View
Thumbnail Image
Item

Pressing: Smooth Isosurfaces with Flats from Binary Grids

2006 , Chica, Antonio , Williams, Jason Daniel , Andujar, Carlos , Brunet, Pere , Navazo, Isabel , Rossignac, Jarek , Vinacua, A.

We propose an approach, called Pressing, for smoothing isosurfaces extracted from binary volumes while recovering their large planar regions (flats). Pressing uses global optimization to identify flats and constrained bilaplacian smoothing to eliminate noise from the isosurface. It recovers sharp edges between flats and between flat and smooth regions, yielding a more accurate approximation of the original solid than isosurfaces produced by previously proposed approaches. The result may benefit shape recognition, simplification, compression, and various reverse engineering and manufacturing applications.

View