(A more complete list can be seen at DBLP.)


Application-Driven Compression for Visualizing Large-Scale Time-Varying Volume Data

Chaoli Wang, Hongfeng Yu, and Kwan-Liu Ma

IEEE Computer Graphics and Applications
(Accepted for publication)

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In many areas of science and engineering, the desires to study a subject at the highest possible resolution have led to an explosive growth of data. It becomes imperative to reduce the data to a manageable scale for analysis and visualization. For high-precision floating-point data, compressing the data solely based on values can only achieve limited saving. Further reduction is possible by utilizing the fact that usually only a smaller subset of the data is of interest in analysis ...


Parallel Volume Rendering using 2-3 Swap Image Compositing for an Arbitrary Number of Processors

Hongfeng Yu, Chaoli Wang, and Kwan-Liu Ma

In Proceedings of Proceedings of IEEE/ACM Supercomputing 2008 Conference
(Accepted for publication)
November, 2008

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The ever-increasing amounts of simulation data produced by scientists demand high-end visualization capability. Parallel rendering is a viable solution to address this issue by distributing both the data and rendering calculations among processors. However, image compositing, which requires inter-processor communication, is often the bottleneck stage for parallel rendering of large volume data sets. Existing image compositing solutions either incur a large number of messages exchanged among processors (such as the direct send method), or limit the number of processors that can be effectively utilized (such as the binary swap method) ...


Rapid Graph Layout using Space Filling Curves

Chris Muelder and Kwan-Liu Ma

IEEE Transactions on Visualization and Computer Graphics
(also Information Visualization 2008 Conference Proceedings)
Volume 14, Number 6, October, 2008, pp. 1301-1308

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Network data frequently arises in a wide variety of fields, and node-link diagrams are a very natural and intuitive representation of such data. In order for a node-link diagram to be effective, the nodes must be arranged well on the screen. While many graph layout algorithms exist for this purpose, they often have limitations such as high computational complexity or node colocation ...


Size-based Transfer Functions: A New Volume Exploration Technique

Carlos Correa and Kwan-Liu Ma

IEEE Transactions on Visualization and Computer Graphics
(Also IEEE Visualization 2008 Conference Proceedings)
Volume 14, Number 6, October, 2008, pp. 1380-1387

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The visualization of complex 3D images remains a challenge, a fact that is magnified by the difficulty to classify or segment volume data. In this paper, we introduce size-based transfer functions, which map the local scale of features to color and opacity. Features in a data set with similar or identical scalar values can be classified based on their relative size ...


Importance-Driven Time-Varying Data Visuaization

Chaoli Wang, Hongfeng Yu, and Kwan-Liu Ma

IEEE Transactions on Visualization and Computer Graphics
(Also IEEE Visualization 2008 Conference Proceedings)
Volume 14, Number 6, October, 2008, pp. 1547-1554

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The ability to identify and present the most essential aspects of time-varying data is critically important in many areas of science and engineering. This paper introduces an importance-driven approach to time-varying volume data visualization for enhancing that ability. By conducting a block-wise analysis of the data in the joint feature-temporal space, we derive an importance curve for each data block based on the formulation of conditional entropy from information theory ...


BGPeep: An IP-space Centered View for Internet Routing Data

James Shearer, Kwan-Liu Ma,, and Toby Kohlenberg

In Proceedings of VizSEC 2008
(Accepted for presentation and publication)
September, 2008

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We present BGPeep, a tool for visualizing Border Gateway Protocol traffic at a detailed level, using a novel depiction of IP-space. This new visualization renders the network prefixes involved with such traffic using a method that leverages the peculiarities of BGP traffic to gain insight and highlight potential router misconfigurations. BGPeep utilizes a simple interface and several methods of interaction to allow users to quickly focus on the data of interest ...


An Integrated Exploration Approach to Visualizing Multivariate Particle Data

Chad Jones, Kwan-Liu Ma, Stephane Ethier, Wei-Li Lee

Computing in Science & Engineering
Volume 10, Number 4, July/August, 2008, pp. 20-29

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The authors describe a data exploration system that visualizes time-varying, multivariate, point-based data from gyrokinetic particle simulations. By using two interaction modes, their system lets researchers explore collections of densely packed particles and discover
interesting aspects, such as the location and motion of particles trapped in turbulent
plasma flow. ...


Visualization and Parallel I/O at Extreme Scale

Rob Ross, Tom Peterka Han-Wei Shen, Kwan-Liu Ma, Hongfeng Yu, and Ken Moreland

Journal of Physics (Conference Series)
Volume 125, July, 2008

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In our efforts to solve ever more challenging problems through computational techniques, the scale of our compute systems continues to grow. As we approach petascale, it becomes increasingly important that all the resources in the system be used as efficiently as possible, not just the floating-point units. Because of hardware, software, and usability challenges, storage resources are often one of the most poorly used and performing components of today's compute systems ...


A Statistical Approach to Volume Data Quality Assessment

Chaoli Wang, Kwan-Liu Ma

IEEE Transactions on Visualization and Computer Graphics
Volume 14, Number 3, May/June, 2008, pp. 590-602

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Quality assessment plays a crucial role in data analysis. In this paper, we present a reduced-reference approach to volume data quality assessment. Our algorithm extracts important statistical information from the original data in the wavelet domain. Using the extracted information as feature and predefined distance functions, we are able to identify and quantify the quality loss in the reduced or distorted version of data, eliminating the need to access the original data ...


Social-Aware Collaborative Visualization for Large Scientific Projects

Kwan-Liu Ma, Chaoli Wang

In Proceedings of International Symposium on Collaborative Technologies and Systems
May, 2008

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This paper discusses how to better support collaborative work for large scientific projects using visualization. Particular considerations are given to knowledge sharing and the social aspect of collaboration. The goal is to provide a roadmap for creating next-generation collaborative technologies with visual and social augmentation. ...


A Scalable Parallel Force-Directed Graph Layout Algorithm

Anna Tikhonova and Kwan-Liu Ma

In Proceedings of Eurographics Parallel Graphics and Visualization Symposium (EGPGV 2008)
April, 2008, pp. 25-32

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Understanding the structure, dynamics, and evolution of large graphs is becoming increasingly important in a variety of fields. The demand for visual tools to aid in this process is rising accordingly. Yet, many algorithms that create good representations of small and medium-sized graphs do not scale to larger graph sizes. The exploitation of the massive computational power provided by parallel and distributed computing is a natural progression for handling important problems such as large graph layout ...


Parallel Volume Rendering on the IBM Blue Gene/P

Tom Peterka, Hongfeng Yu, Robert Ross, and Kwan-Liu Ma

In Proceedings of Eurographics Parallel Graphics and Visualization Symposium (EGPGV 2008)
April, 2008, pp. 73-80

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Parallel volume rendering is implemented and tested on an IBM Blue Gene distributed-memory parallel architecture. The goal of studying the cost of parallel rendering on a new class of supercomputers such as the Blue Gene/P is not necessarily to achieve real-time rendering rates. It is to identify and understand the extent of
bottlenecks and interactions between various components that affect the design of future visualization solutions on these machines, solutions that may offer alternatives to hardware-accelerated volume rendering, for example, when large volumes, large image sizes, and very high quality results are dictated by peta- and exascale data ...


MobiVis: A Visualization System for Exploring Mobile Data

Zeqian Shen, Kwan-Liu Ma

In Proceedings of IEEE Pacific Visualization Symposium
IEEE VGTC, March, 2008, pp. 175-182

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The widespread use of mobile devices brings opportunities to capture large-scale, continuous information about human behavior. Mobile data has tremendous value, leading to business opportunities, market strategies, security concerns, etc. Visual analytics systems that support interactive exploration and discovery are needed to extracting insight from the data. However, visual analysis of complex social-spatial-temporal mobile data presents several challenges. We have created MobiVis, a visual analytics tool, which incorporates the idea of presenting social and spatial information in one heterogeneous network ...


StarGate: A Unified, Interactive Visualization of Software Projects

Michael Ogawa and Kwan-Liu Ma

In Proceedings of IEEE PacificVis Conference
March, 2008, pp. 191-198

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With the success of open source software projects, such as Apache and Mozilla, comes the opportunity to study the development process. In this paper, we present StarGate: a novel system for visualizing software projects. Whereas previous software project visualizations concentrated mainly on the source code changes, we literally place the developers in the center of our design. Developers are grouped visually into clusters corresponding to the areas of the file repository they work on the most. ...


Pixelplexing: Gaining Display Resolution Through Time

James Shearer, Michael Ogawa, Kwan-Liu Ma, Toby Kohlenberg

In Proceedings of IEEE Pacific Visualization Symposium
IEEE VGTC, March, 2008, pp. 159-266

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Animation is frequently utilized to visually depict change in time-varying data sets. For this task, it is a natural fit. Yet explicit animation is rarely employed for static data. We discuss the use of animation to overcome three common limitations faced by information visualization applications in the context of small-display devices: constraints on the output display, limited interaction possibilities, and high data density ...


Multiple Uncertainties in Time-Variant Cosmological Particle Data

Steve Haroz, Kwan-Liu Ma, Katrin Heitmann

In Proceedings of IEEE Pacific Visualization Symposium
IEEE VGTC, March, 2008, pp. 207-214

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We utilize multiple views for interactive dataset exploration and selection of important features, and we apply those techniques to the unique challenges of cosmological particle datasets. We show how interactivity and incorporation of multiple visualization techniques help overcome the problem of limited visualization dimensions and allow many types of uncertainty to be seen in correlation with other variables. ...