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| APPLICANT SEMINAR: Interactive 3D Visualization of Time-Varying Curvilinear Grid and the Evaluation of Scientific Visualization | ||||
| Yuan Chen | On: | 3-Mar-2008 11:00 AM - 12:30 PM | ||
| PhD Student | At: | Watson Research Center (Hawthorne), Room GN-K35 | ||
| Johns Hopkins University | Host: | James T Klosowski | ||
Abstract: In this talk, I will present our efforts in developing algorithms for improving scientific visualization in two areas: 1) 3D texture-based algorithm for visualization of time-varying curvilinear grid. 2) Error evaluation for scalar and vector field visualizations. We proposed a novel scheme to interactively visualize time-varying scalar fields defined on a curvilinear grid. Interactive rendering can be achieved for large 3D grid with over 2.3 million vertices and hundreds of time steps. Utilizing the topological uniformity of curvilinear grid and the 3D texture mapping feature of modern graphics card, we reduces the problem of rendering a curvilinear grid to the problem of rendering a regular grid with one additional texture lookup. Our approach eliminated the need to resample the scalar data for each time steps and maintains a relatively low space requirement for storing and transmitting the data. For data exploration and analysis in scientific visualization, accuracy is one of major concerns of a strategy’s applicability. We introduced an error evaluation strategy, which can be used for both scalar and vector field visualization. It is based on the idea that scientific visualization is an alternative representation for the original data field. If the visualization successfully represents most of information contained in the field, then the field data could be fully reconstructed from the visualization. We used this strategy to develop error functions for our texture-based scalar field visualization and streamline-based vector field visualization. Both error functions provide the quantitative measurement of representations. The results are in accord with human perception in many aspects. | ||||
| Classical Problems in Computational Geometry: Reconfiguring Chains - A Perspective on Twenty Years of a Developing Field | ||||
| Sue Whitesides | On: | 8-Nov-2007 02:00 PM - 03:00 PM | ||
| Professor & Director of the Computer Science Department | At: | Watson Research Center (Hawthorne), Room GN-K35 | ||
| McGill University | Host: | Jon Lenchner | ||
Abstract: Despite their geometric simplicity, chains of links (also known as "arms" or "carpenter's rulers") display a variety of intriguing behaviors. We survey results from the last twenty years from an algorithmic perspective. No prior background in computational geometry is assumed. Speaker biography: Sue Whitesides is professor and current director of the School of Computer Science of McGill University. She worked her way through Stanford writing case studies for the Design Division of Mechanical Engineering, completing a Master's Degree in EE. After a brief stint in the machine tool industry, she entered the University of Wisconsin, completing a Ph.D. in Mathematics in 1975. She served on the Math Dept. faculties at Tufts University and Dartmouth College before joining McGill in CS in 1983. Her research interests include geometric algorithms and discrete mathematics, with applications to graph layout problems, robot motion planning, and brain imaging. | ||||
| Visualizing Software Space | ||||
| Michele Lanza | On: | 25-Oct-2007 02:00 PM - 03:00 PM | ||
| Assistant Professor | At: | Watson Research Center (Hawthorne), Room 1S-F40 | ||
| University of Lugano | Host: | Wim De Pauw | ||
Abstract: In software visualization, many attempts to visually represent the structure of software systems have been proposed, essentially through flat representations. However, the quantity of information that can be represented in 2D drawings is limited. Handling the complexity and observing the evolution of very large software systems requires the analysis of large complex data models and the creation of condensed views of the system. In the context of visualization, software metrics have been used to compute and enrich such condensed views. However, current techniques concentrate on visualizing data of one particular software release, providing insufficient support for visualizing data of several releases. Our goal is to exploit multi- dimensional navigation spaces to efficiently visualize evolving software systems. This leads to a number of questions: 1. How can we efficiently visualize (evolving) software systems in 3D by finding the right visual metaphor and by preserving the usefulness (from a reverse engineering point of view) of the obtained views? 2. How can we efficiently interact with and navigate such multi-dimensional spaces without incurring into navigational complexity (i.e., getting "lost") or friction (i.e., being "too slow")? 3. How can the discovered visual means contribute to the already existing body of reverse engineering methodology to understand and evolve industrial size software systems? In this talk I will present research that we performed in the last two years in the context of the "EvoSpaces" project, whose goal is to answer the above questions. We realized a navigable and interactive 3D environment for software exploration, based on the metaphor of a city, i.e., software systems are visualized as cities. Speaker biography: Michele Lanza is assistant professor at and co-founder of the faculty of informatics of the University of Lugano, in Switzerland. His doctoral dissertation, completed in 2003, received the prestigious European Ernst Denert award for best thesis in software engineering of 2003. He leads the REVEAL research group, focusing on the areas of software evolution, visualization, and reverse engineering. He authored more than 40 technical papers and is author of the recently published book ``Object-Oriented Metrics in Practice''. He is an active member of the ACM and the IEEE Computer Society where he has served on more than 30 program committees. He was program co-chair of MSR 2007 (the 4th International Workshop on Mining Software Repositories) and IWPSE 2007 (the 9th International Workshop on Principles of Software Evolution). He is steering committee member of VISSOFT (the international workshop on Visualizing Software) and CHOOSE (the Swiss Object-Oriented Software Engineering society). | ||||