Timothy Urness - research and publications

Visualization of Energy Minimization in Ferromagnetic Systems
Midwest Instruction and Computing Symposium
Proceedings of MICS 2008
Awarded Best Student Paper
Zachary Oler and Timothy Urness

Many different studies of magnetism models have presented theories on energy minimization. These studies, however, do not give a visual confirmation of what is occurring during minimization. In this paper, we describe a model and visualization system designed to illustrate the principles of energy minimization in magnetic systems.

Teaching File Input/Output, Loops, and If-Statements via a Red Eye Reduction Assignment
Consortium for Computing Sciences in Colleges
Journal of Computing Sciences in Colleges, Volume 23 Issue 4
Timothy Urness

This paper describes a "nifty" programming assignment that requires students to use files, loops, and if-statements to implement an algorithm that will remove the red-eye artifact from an image. The assignment is most suitable for a CS1 course, but could be altered to accommodate a CS0 or CS2 course.

Streamline Visualization of Multiple 2D Vector Fields
Visualization and Data Analysis 2008
Proceedings of SPIE-IS&T Electronic Imaging, SPIE Vol. 6809-9
Timothy Urness and Victoria Interrante

The analysis of data that consists of multiple vector fields can be greatly facilitated by the simultaneous visualization of the vector fields. An effective visualization must accurately reflect the key physical structures of the fields in a way that does not allow for an unintended bias towards one distribution. While there are several effective techniques to visualize a single vector field through equally-spaced streamlines, applying these techniques to individual vector fields and combining them in a single image yields several undesirable artifacts. In this paper, we present strategies for the effective visualization of two vector fields through the use of streamlines.

Teaching Computer Organization/Architecture by Building a Computer
2007 Workshop on Computer Architecture Education
Timothy Urness

This paper describes a series of exercises and assignments suggested for an introductory computer organization or computer architecture course. The primary objective of these exercises is to engage a class of students by introducing the practical, hands-on application of assembling a computer by selecting and purchasing individual components.

FieldVis: A Tool for Visualizing Astrophysical Magnetohydrodynamic Flow
IEEE Computer Graphics and Applications, January/February 2007
Blayne Field, Sean O'Neill, Timothy Urness, Victoria Interrante, and Thomas W. Jones

Our group is involved in magnetohydrodynamic simulations that track the time and space evolution of the full 3D velocity and magnetic vector fields, plus fundamental scalar fields such as density and pressure. To accomplish the complex visualization of these jets, we developed FieldVis, a simulation tool that focuses primarily on representing 3D vector and scalar fields.

Directional Enhancement in Texture-based Vector Field Visualization
Graphite 2006
Francesca Taponecco, Timothy Urness, and Victoria Interrante

The use of textures provides a rich and diverse set of possibilities for the visualization of flow data. We present methods designed to produce oriented and controlled textures that accurately reflect the complex patterns that occur in vector field visualizations.

Strategies for the Visualization of Multiple 2D Vector Fields
IEEE Computer Graphics and Applications, July/August 2006
Timothy Urness, Victoria Interrante, Ellen Longmire, Ivan Marusic, Sean O'Neill, and Thomas W. Jones

Strategies for effectively visualizing co-located 2D vector fields enable understanding of key physical structures of one vector field within the context of a related vector field. We describe the range of effects possible by combining several existing flow visualization techniques for analyzing multiple vector fields.

Texture-Based Visualization of Multi-Field Flow Data
Ph.D. Dissertation, May 2006
University of Minnesota
Department of Computer Science and Engineering
Timothy Urness

The goal through this work is to enable researchers to obtain a succinct, meaningful visual summary of the contents of a dataset that consists of multiple, coincident variables. This is accomplished through providing techniques that allow the creation of an image in which the important features of multiple scalar or vector fields can be understood both independently and in the context of the other fields.

Techniques for Visualizing Multi-Valued Flow Data
Eurographics/IEEE TCVG Symposium on Visualization 2004
Timothy Urness, Victoria Interrante, Ellen Longmire, Ivan Marusic, and Bharathram Ganapathisubramani

We discuss several techniques to display scalar distributions within an image depicting a 2D flow field. We address how contrast and luminance can effectively be used, present modifications to an algorithm that uses dense streamlines to represent flow direction, and present a new technique, based on embossing, to encode the out-of-plane component of a 3D vector field over a 2D domain.

Animations
mpeg movie and interactive java applet
Timothy Urness, 2003

The vector field in any visualization is dependent on the relative velocity of the observer. Traditionally, the average value of the streamwise component of the global vector field is calculated and subtracted from each vector. However, the resulting LIC image, critical points, and vector field features are greatly influenced by the magnitude of the value subtracted from the streamwise velocity. Examples of this phenomenon are shown here.

Effectively Visualizing Multi-Valued Flow Data Using Color and Texture
IEEE Visualization 2003
Timothy Urness, Victoria Interrante, Ivan Marusic, Ellen Longmire, and Bharathram Ganapathisubramani

In this paper we offer several new insights and techniques for effectively using color and texture to simultaneously convey information about multiple 2D scalar and vector distributions, in a way that facilitates allowing each distribution to be understood both individually and in the context of one or more of the other distributions.

Effective Visualization of Stereo PIV Vector Fields of a Turbulent Boundary Layer
Journal of Turbulence, Article 23, Volume 4, 2003.
E. K. Longmire, B Ganapathisubramani, I Marusic, T Urness, and V Interrante

Stereo PIV datasets contain three dimensional information over a plane from which multiple quantities can be derived at each point. The task of visualizing these different parameters simultaneously is challenging and this inhibits our ability to analyze and derive firm conclusions about the physics of the flow. In this paper, we discuss several different ways in which the primary quantities can be viewed simultaneously in the same image.

Techniques for Visualizing Multi-Valued Flow Data
Master of Science Thesis, May 2003
University of Minnesota
Department of Computer Science and Engineering
Timothy Urness

We present several techniques to effectively visualize multi-valued flow data using contrast, color, 3D visualization, and texture. The ultimate goal through this work is to enable researchers to obtain a succinct, meaningful visual summary of the contents of a dataset through providing techniques that allow the creation of images in which the important features of multiple scalar distributions can be understood both independently and in the context of multiple other distributions.

Structure Identification and Analysis in Turbulent Boundary Layers by Stereo PIV
4th International Symposium on Particle Image Velocimetry, 2001
E. K. Longmire, B. Ganapathisubramani, I. Marusic, T. Urness

The objective of this study is to apply Stereo PIV in streamwise-spanwise planes to measure three-dimensional velocity fields and to develop methods for the identification of typical flow structures. These methods can then be applied to quantify the strength, size, and frequency of various structures and therefore to examine the existence, nature, and symmetry of hairpin-like vortices and vortex packets.

Analyzing Industrial Furnace Efficiency Using Comparative Visualization in a Virtual Reality Environment
Proceedings of the 1999 ASME International Mechanical Engineering Congress and Exposition, pages 191-199.
Lori Frietag and Tim Urness

We describe an interactive toolkit used to perform comparative analysis of two or more data sets arising from numerical simulations. An industrial application aimed at designing an efficient, low-NOx burner for industrial furnaces is used. Critical insights are obtained by interactively adjusted color maps, data culling, and data manipulation. New paradigms for scaling small values in the data comparison technique are described. The display device used for this application was the CAVE virtual reality theater, and we describe the user interface to the visualization toolkit and the benefits of immersive 3D visualization for comparative analysis.