Publications
Visual Analysis of Large Heterogeneous Social Networks by Semantic and Structural Abstractions
Zeqian Shen, Kwan-Liu Ma, and Tina Eliassi-RadIEEE Transactions on Visualization and Computer Graphics
Volume 12, Number 6, November/December, 2006, pp. 1427-1439Social network analysis is an active area of study beyond sociology. It uncovers the invisible relationships between actors in a network and provides understanding of social processes and behaviors. It has become an important technique in a variety of application areas such as the Web, organizational studies, and homeland security. This paper presents a visual analytics tool, OntoVis, for understanding large, heterogeneous social networks, in which nodes and links could represent different concepts and relations, respectively ...
Layout of Multiple Views for Volume Visualization: A User Study
Daniel Lewis, Steve Haroz, and Kwan-Liu MaIn Proceedings of International Symposium on Visual Computing
November, 2006, pp. 215-226Volume visualizations can have drastically different appearances when viewed using a variety of transfer functions. A problem then occurs in trying to organize many different views on one screen. We conducted a user study of four layout techniques for these multiple views. We timed participants as they separated different aspects of volume data for both time-invariant and time-variant data using one of four different layout schemes ...
From Mesh Generation to Scientific Visualization: An End-to-End Approach to Parallel Supercomputing (DVD Proceedings)
Tiankai Tu, Hongfeng Yu, Leonardo Ramirez-Guzman, Jacobo Bielak, Omar Ghattas, Kwan-Liu Ma, and David R. O'HallaronIn Proceedings of the International Conference for High Performance Computing, Networking, Storage and Analysis
November, 2006Traditionally, parallel supercomputing has focused on the inner kernel of scientific simulations: the solver. The front and back ends of the simulation pipeline--problem description and interpretation of the output--have taken a back seat to the solver when it comes to attention paid to scalability and performance, and are often relegated to offline, sequential computation. As the largest simulations move beyond the realm of the terascale and into the petascale, this decomposition in tasks and platforms becomes increasingly untenable. ...
Interactive Multi-Scale Exploration for Volume Classification
Eric Lum, James Shearer, and Kwan-Liu MaIn Proceedings of Pacific Graphics 2006 Conference, also as a special issue of Visual Computer
October, 2006, pp. 622-630Filter banks are a class of signal processing techniques that can be used to reveal the local energy of a signal at multiple scales. Utilizing such filtering allows us to consider local texture and other data characteristics, and permits volume classification and visualization that cannot be accomplished easily using conventional, transfer function-based methods. Our filter bank approach increases the dimensionality, and thus, the complexity of the classification task ...
SciVis, InfoVis -- bridging the community divide?!
Daniel Weiskopf, Kwan-Liu Ma, Jarke J. van Wijk, Robert Kosara, and Helwig HauserVisualization 2006 Conference DVD
October, 2006Scientific Visualization (SciVis) and Information Visualization (InfoVis) are well-established and often used terms in the research field of visualization. But instead of intuitively illustrating two research fields - with disjunctive goals, challenges, and approaches - which they are not, this terminology of SciVis vs. InfoVis rather represents a manifested community divide: there are SciVis researchers and there are InfoVis researchers (and there are only a few who appear on both sides), there are SciVis conferences/journals and there are InfoVis conferences/journals, etc ...
Quantitative and Comparative Visualization Applied to Cosmological Simulations
James Ahrens, Katrin Heitmann, Salman Habib, Lee Ankeny, Patrick McCormick, Jeff Inman, Ryan Armstrong, and Kwan-Liu MaJournal of Physics: Conference Series
Volume 46, June, 2006, pp. 526-534Cosmological simulations follow the formation of nonlinear structure in dark and luminous matter. The associated simulation volumes and dynamic range are very large, making visualization both a necessary and challenging aspect of the analysis of these datasets. Our goal is to understand sources of inconsistency between different simulation codes that are started from the same initial conditions. Quantitative visualization supports the definition and reasoning about analytically defined features of interest ...
A Scalable, Hybrid Scheme for Volume Rendering Massive Data Sets
Hank Childs, Mark Duchaineau, and Kwan-Liu MaIn Proceedings of Eurographics Symposium on Parallel Graphics and Visualization
May, 2006, pp. 153-162We introduce a parallel, distributed memory algorithm for volume rendering massive data sets. The algorithm's scalability has been demonstrated up to 400 processors, rendering one hundred million unstructured elements in under one second. The heart of the algorithm is a hybrid approach that parallelizes over both the elements of the input data and over the pixels of the output image. At each stage of the algorithm, there are strong limits on how much work each processor performs, ensuring good parallel effciency ...
Multi-Layered Image Caching for Distributed Rendering of Large Multiresolution Data
Jonathan Strasser, Valerio Pascucci, and Kwan-Liu MaIn Proceedings of Eurographics Symposium on Parallel Graphics and Visualization
May, 2006, pp. 171-177The capability to visualize large volume datasets has applications in a myriad of scientic elds. This paper presents a large data visualization solution in the form of distributed, multiresolution, progressive processing. This solution reduces the problem of rendering a large volume data into many simple and independent problems that can be straightforwardly distributed to multiple computers. By completely decoupling rendering and display with image caching, we are able to maintain a high level of interactivity during exploration of the data, which is key to obtaining insights into the data ...
Natural Visualization
Steve Haroz and Kwan-Liu MaIn Proceedings of Eurographics Visualization Symposium
May, 2006, pp. 43-50This paper demonstrates the prevalence of a shared haracteristic between visualizations and images of nature. We have analyzed visualization competitions and user studies of visualizations and found that the more preferred, better performing visualizations exhibit more natural characteristics. Due to our brain being wired to perceive natural images, testing a visualization for properties similar to those of natural images can help show how well our brain is capable of absorbing the data ...
Simultaneous Classification of Time-Varying Volume Data Based on the Time Histogram
Hiroshi Akiba, Nathan Fout, and Kwan-Liu MaIn Proceedings of Eurographics Visualization Symposium
May, 2006, pp. 1-8An important challenge in the application of direct volume rendering to time-varying data is the specification of transfer functions for all time steps. Very little research has been devoted to this problem, however. To address this issue we propose an approach which allows simultaneous classification of the entire time series. We explore options for transfer function specification that are based, either directly or indirectly, on the time histogram ...
Evaluating the Effectiveness of Tree Visualization Systems for Knowledge Discovery
Yue Wang, Soon Tee Teoh, and Kwan-Liu MaIn Proceedings of Eurographics Visualization Symposium
May, 2006, pp. 67-74User studies, evaluations, and comparisons of tree visualization systems have so far focused on questions that can readily be answered by simple, automated queries without needing visualization. Studies are lacking on the actual use of tree visualization in discovering intrinsic, hidden, non-trivial and potentially valuable knowledge. We have thus formulated a set of tree exploration tasks not previously considered and have performed user studies and analysis to determine how visualization helps users to perform these tasks ...
Ultra Scale Visualization
Kwan-Liu MaIn Proceedings of Transdisciplinary Fluid Integration 2006
April, 2006, pp. 7-14Large parallel computing systems give scientists the power to model and visualize physical phenomena and chemical processes at a stunning degree of precision and sophistication leading to profound levels of insight and understanding. I will introduce new techniques and concepts promising us to visualize and explore terabyte-scale data to its full extent, and show the impact of these new technologies on a wide range of science endeavors from turbulent combustion to fusion, from meteorology to geophysics, from particle physics to astrophysics ...
Visualization for Cybersecurity
Kwan-Liu MaIEEE Computer Graphics and Applications
Volume 26, Number 2, March/April, 2006, pp. 26-27Networked computers have become an integral part of our everyday life, used for a variety of purposes at home, in the workplace, and at schools. They are so ubiquitous and easy to access that they are also vulnerable. Any computer exposed to the Internet is likely to be regularly scanned and attacked by both automated and manual means. Both organizations and individuals are making every effort to build and maintain trustworthy computing systems ...
BiblioViz: A System for Visualizing Bibliography Information
Zeqian Shen, Michael Ogawa, Soon Tee Teoh, and Kwan-Liu MaIn Proceedings of 2006 Asia-Pacific Symposium on Information Visualization
February, 2006, pp. 93 - 102The InfoVis 2004 contest led to the development of several bibliography visualization systems. Even though each of these systems offers some unique views of the bibliography data, there is no single best system offering all the desired views. We have thus studied how to consolidate the desirable unctionalities of these systems into a cohesive design. We have also designed a few novel visualization methods ...
Cyber Security Through Visualization
Kwan-Liu MaIn Proceedings of 2006 Asia-Pacific Symposium on Information Visualization
February, 2006, pp. 3-7Networked computers are subject to attack, misuse, and abuse. Organizations and individuals are making every effort to build and maintain trustworthy computing systems. The main strategy is to closely monitor and inspect network activities by collecting and analyzing data about the network traffic and the trails of system usage. The analysis usually requires large amounts of finely detailed, high-dimensional data to enable analysts to uncover hidden threats and make calculated predictions in a timely fashion. ...