Research Projects

Current Projects

CHAOS: Pattern Formation
Web	The goal of this research is the development of widely applicable tools for analyzing the dynamics of pattern formation by studying a combustion experiment. The flame front in this experiment is flat and precisely controllable allowing accurate video acquisition of spatiotemporal information. With its hundreds of dynamic modes and two-dimensional spatial structure, this experimental system is uniquely suited for fundamental study pattern formation. The work involves a long-term collaboration with Physicist Michael Gorman of the University of Houston. While techniques for extracting information such as fractal dimension from time series are well-known, analogous techniques for spatiotemporal data are not well-developed. Using our work in detection of stable patterns and symmetries, we are developing sophisticated image processing techniques and visualization techniques for categorizing pattern-forming systems from their images.
Davis: Data Viewing System
Web	Davis (Data Viewing System) is a general-purpose data viewer designed for the simultaneous display of a large number of dynamic data sets. Davis was inspired by the need to explore computational models of the cerebral cortex. These systems are distinguished by complex dynamic elements interconnected in irregular patterns. Neuroscientists study the detailed behavior of individual elements and how these elements interact to achieve cortical function. This paper describes Davis and its use in cortical visualization. Davis is written in Java and can be run from a browser or as a standalone application. Users must provide an XML description of their data, which Davis uses for its menus, browsing and visualization. Davis visualizations can be applied to any collection of space-time data sets, and the Davis infrastructure allows visualizations to be added easily.
Turtle Cortex: Understanding Cortical Waves
Web	This project brings together a collaborative team consisting of two neurobiologists (David Senseman in San Antonio and Philip Ulinski in Chicago), a systems engineer (Bijoy Ghosh in St. Louis) and a computer scientist (Kay Robbins in San Antonio) who are working together to understand the mechanisms and structure that underlie the mapping of visual information into the complex internal representation of the turtle visual cortex. Information about position in visual space is coded in topographic maps within the sensory cortices of mammals. By contrast, the visual cortex of freshwater turtles does not embody topographically-organized representations of the visual world. Single unit recording experiments in turtles reveal that neurons at any position in visual space respond to stimuli presented anywhere in binocular visual space. Interestingly, voltage sensitive dye (VSD) experiments with an in vitro preparation of the eyes and brain of turtles show that visual stimuli evoke waves of depolarizing activity that propagate across visual cortex. These waves can be conveniently represented as movies.
Waves And Synchronization
Web	Waves are a fundamental mechanism for conveying information in spatiotemporal systems. The goal of this research is the development of tools and techniques for analyzing and visualizing wave motion in data. We have developed a new technique, wave subspaces, which can be used to construct a two-dimensional caricature. Features of the caricature allow one to understand the space-time behavior of the wave motion. Because the geometry is factored out, these techniques allow one to compare data from trials with different spatial geometries and to compare model and experimental data. Wave subspaces can also be used as the basis for visualization tools.
Web-Based Electronic Laboratories
Web	The geometric increase in computer power and the ubiquitous availability of network connectivity are revolutionizing computing. A computer science curriculum based on old teaching techniques may seem dull and irrelevant to the modern student. Instruction in the undergraduate curriculum for the most part does not make active use of new technology. A multimedia presentation during a lecture by an instructor is considered to be a passive use of technology. In contrast, a student who can control a multimedia visualization is making active use of such technology. The difference between passive and active use of technology is similar to the difference between watching a laboratory demonstration and performing an experiment. Aside from making the learning experience more interesting, a well-designed experiment can challenge the student and encourage creativity. A user-controlled animation can have a similar effect and provide the student with a virtual laboratory environment. In this project a curriculum for undergraduate operating systems and computer network courses based on active use of animations and simulations on the web are being developed. A framework for constructing active animations will be set up so that these animations can be efficiently produced. This work is supported by the National Science Foundation.
MicroMetal: Microarray Meta-Analysis
Web	The aim of this project is the design and development of a new microarray investigatory software tool. Being conscious of the research process, a primary aim of the design is to guide the user through complete hypothesis testing procedures. User interaction with the software centers around a wizard-style interface that organizes the elements of a well defined research process into a logical step-by-step procedure. Furthermore, great importance has been placed on the user's ability to easily access and efficiently utilize publicly available experimental data, so that knowledge can be inferred from a variety of sources simultaneously.

Completed Projects

Distributed Neural Processing
Web	The long-term goal of this research program is the development of fundamental understanding of the perception of visual motion. In this joint project with David Senseman of the Division of Life Sciences voltage sensitive dye is used to image cortical activity onto a large photodiode array to produce high-speed movies of cortical activity during the processing of visual information. The particularly favorable experimental preparation allows accurate capture of both spatial and temporal structure of the electrical response to produce cortical movies that are analyzed using real-time visualization techniques.
JOTSA: Exact Time Animation
Web	JOTSA (Java On Time Synchronous Animation) is an environment for web-based animation of algorithms and data. On time refers to the moving of objects so that they complete their movement at a known time, independent of the hardware or operating system of the target machine. Synchronous refers to the coordination of the movement of several objects. JOTSA was motivated by the need to represent exact timing relationships in network protocols and other time-critical applications in a platform-independent manner. JOTSA provides a web-based user interface which is a natural vehicle for remote execution and wide dissemination. In addition to exact time animation, JOTSA supports multiple dependent or independent views, panning and zooming, linking of collections of objects, event-driven simulation, and synchronization. Applications have the full resources of the Java virtual machine and can be written to support interaction in a way that is familiar to the user.
Visualization of Mobily Acquired Geophysical Data
Web	The goal of this research is the development of effective visualization techniques for data that is acquired while the acquisition system is moving. Spatial positioning information must be integrated into both the data acquisition and the visualization process. The project has been involved in applications based on aerial, foot and bicycle acquisition systems. Timing and positioning considerations vary considerably over this range of applications. Students are working with scientists at the National Science Foundation SOAR project on the Antarctic aerial ice pack survey and scientists at Southwest Research Institute (SWRI) on geophysical volcanic surveys.
Visualization of Scientific Video Data
Web	The objectives of this project are to develop practical tools for online analysis and visualization of spatiotemporal data acquired from laboratory experiments and numerical simulation. The goal is to produce systems that promote collaborative visualization and remote access and take advantage of distributed computing resources to attain near-realtime performance. The project is oriented towards the seamless acquisition and analysis of video data in order to detect transitions during the running of experiments and simulations. Fast visualization techniques based on tiling, extraction and projection are being developed to allow experimentalists to compare dynamic structure across collections of movies. These facilities are designed to support experimental steering and to allow scientists to map out bifurcation structure as experimental parameters are changed.
Visualization of Systems
Web	The goal of this research is the development of tools and techniques for visualizing systems, with particular emphasis on techniques that can be used while simulations or experimental measurements are in progress. Past work has looked at techniques for animating performance of ATM switches and models of parallel memory performance. Current work is focusing on visualization of processes that split and merge.