KWAN-LIU MA


PUBLICATIONS

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

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Interactive Visual Analysis of Hierarchical Enterprise Data

Yu-Hsuan Chan, Kimberly Keeton, and Kwan-Liu Ma

In Proceedings of the 12th IEEE Conference on Commerce and Enterprise Computing
November, 2010

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In this paper, we present an interactive visual technique for analyzing and understanding hierarchical data, which we have applied to analyzing a corpus of technical reports produced by a corporate research laboratory. The analysis begins by selecting a known entity, such as a topic, a report, or a person, and then incrementally adds other entities to the graph based on known relations ...

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View-Dependent Streamlines for 3D Vector Fields

Stephane Marchesin, Cheng-Kai Chen, Chris Ho, and Kwan-Liu Ma

IEEE Transactions on Visualization and Computer Graphics
(also Visualization 2010 Conference Proceedings)
Volume 16, Number 6, October, 2010

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This paper introduces a new streamline placement and selection algorithm for 3D vector fields. Instead of considering the problem as a simple feature search in data space, we base our work on the observation that most streamline fields generate a lot of self-occlusion which prevents proper visualization. In order to avoid this issue, we approach the problem in a view-dependent fashion and dynamically determine a set of streamlines which contributes to data understanding without cluttering the view ...

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Visualization by Proxy: A Novel Framework for Deferred Interaction with Volume Data

Anna Tikhonova, Carlos Correa, and Kwan-Liu Ma

IEEE Transactions on Visualization and Computer Graphics
(Also Visualization 2010 Conference Proceedings)
Volume 16, Number 6, October, 2010

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Interactivity is key to exploration of volume data. Interactivity may be hindered due to many factors, e.g. large data size, high resolution or complexity of a data set, or an expensive rendering algorithm. We present a novel framework for visualizing volume data that allows interactive exploration using proxy images, without accessing the original 3D data. Data exploration using direct volume rendering requires multiple (often redundant) accesses to possibly large amounts of data ...

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Locality-based Visualization for Multi-field Particle Data

Chad Jones and Kwan-Liu Ma

IEEE Transactions on Visualization and Computer Graphics
(Also Visualization 2010 Conference Proceedings)
Volume 16, Number 6, October, 2010

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In flow simulations the behavior and properties of particle trajectories often depend on the physical geometry contained in the simulated environment. Understanding the flow in and around the geometry itself is an important part of analyzing the data. Previous work has often utilized focus+context rendering techniques, with an emphasis on showing trajectories while simplifying or illustratively rendering the physical areas. Our research instead emphasizes the local relationship between particle paths and geometry by using a projected multi-field visualization technique ...

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Visualizing the Commonalities between Hierarchically Structured Data Queries

Chad Jones, Ryan Armstrong, and Kwan-Liu Ma

In Proceedings of the International Conference on Distributed Multimedia Systems
Workshop on Visual Languages and Computing (VLC 2010)
October, 2010

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In this paper we present an information visualiza- tion approach for visualizing the intersection between multiple feature hierarchies. In cases where a dataset has multiple complex features of interest, especially ones that have been hierarchically clustered, it is often very difficult to grasp the commonalities between them. Understanding the overlap between features can help researchers discover correlations or hot spots in their data ...

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Software Evolution Storylines

Michael Ogawa and Kwan-Liu Ma

In Proceedings of ACM Symposium on Software Visualization
(SoftVis 2010)
October, 2010

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This paper presents a technique for visualizing the interactions between developers in software project evolution. The goal is to produce a visualization that shows more detail than animated software histories, like code_swarm, but keeps the same focus on aesthetics and presentation. Our software evolution storylines technique draws inspiration from XKCD's "Movie Narrative Charts" and the aesthetic design of metro maps. ...

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Flow-based Scatterplots for Sensitivity Analysis

Yu-Hsuan Chan, Carlos D. Correa, and Kwan-Liu Ma

In Proceedings of Proceedings of VAST
2010, pp. 43-50

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Visualization of multi-dimensional data is challenging due to the number of complex correlations that may be present in the data but that are difficult to be visually identified. One of the main causes for this problem is the inherent loss of information that occurs when high-dimensional data is projected into 2D or 3D. Although 2D scatterplots are ubiquitous due to their simplicity and familiarity, there are not a lot of variations on their basic metaphor ...

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AniViz: A Template-based Animation Tool for Volume Visualization

Hiroshi Akiba, Chaoli Wang, and Kwan-Liu Ma

IEEE Computer Graphics and Applications
(accepted for publication in March 2009)
Volume 30, Number 3, September/October, 2010, pp. 61-71

pdf bibtex

In the communication of scientific studies and findings, animations are often more effective than still images for showing and explaining complex, dynamic processes, relationships, and structures hidden in the data. This paper introduces AniViz - a tool for making visualization animations. The design of AniViz is mainly based on two principles. First, it is desirable to directly turn the results of data exploration and visualization into the content of an animation that displays the most relevant aspects of the data. ...

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Polygonal Surface Advection Applied to Strange Attractors

Shi Yan, Nelson Max, and Kwan-Liu Ma

Computer Graphics Forum
(also Pacific Graphics 2010 Proceedings)
Volume 29, Number 7, September, 2010

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Strange attractors of 3D vector field flows sometimes have a fractal geometric structure in one dimension, and smooth surface behavior in the other two. General flow visualization methods show the flow dynamics well, but not the fractal structure. Here we approximate the attractor by polygonal surfaces, which reveal the fractal geometry. We start with a polygonal approximation which neglects the fractal dimension, and then deform it by the flow to create multiple sheets of the fractal structure ...

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Parallel Mean Shift for Interactive Volume Segmentation

Fangfang Zhou, Ying Zhao, and Kwan-Liu Ma

In Proceedings of MICCAI Workshop on Machine Learning in Medical Imaging
September, 2010, pp. 67-75

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In this paper we present a parallel dynamic mean shift algorithm based on path transmission for medical volume data segmentation. The algorithm first translates the volume data into a joint position-color feature space subdivided uniformly by bandwidths, and then clusters points in feature space in parallel by iteratively finding its peak point. Over iterations it improves the convergent rate by dynamically updating data points via path transmission and reduces the amount of data points by collapsing overlapping points into one point ...

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Relation-Aware Spreadsheets for Multimodal Volume Segmentation and Visualization

Ling Zheng, Yingcai Wu, and Kwan-Liu Ma

In Proceedings of MICCAI Workshop on Machine Learning in Medical Imaging
September, 2010, pp. 92-99

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Multimodal volume data commonly found in medical imaging applications present both opportunities and challenges to segmentation and visualization tasks. This paper presents a user directed volume segmentation system. Through a spreadsheets interface, the user can interactively examine and refine segmentation results obtained from automatic clustering. In addition, the user can isolate or highlight a feature of interest in a volume based on different modalities, and see the corresponding segmented results ...

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Dynamic Video Narratives

Carlos Correa and Kwan-Liu Ma

ACM Transactions on Graphics
(SIGGRAPH 2010 Technical Paper)
Volume 30, Number 3, 2010

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This paper presents a system for generating dynamic narratives from videos. These narratives are characterized for being compact, coherent and interactive, as inspired by principles of sequential art. Narratives depict the motion of one or several actors over time. Creating compact narratives is challenging as it is desired to combine the video frames in a way that reuses redundant backgrounds and depicts the stages of a motion ...

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An Exploratory Technique for Coherent Visualization of Time-Varying Volume Data

Anna Tikhonova, Carlos Correa, and Kwan-Liu Ma

Computer Graphics Forum
(also Proceedings of EuroVis 2010)
Volume 29, Number 3, June, 2010

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The selection of an appropriate global transfer function is essential for the visualization of time-varying simulation data. This is especially challenging when the global data range is not known in advance, as is often the case in remote and in-situ visualization settings. Since the data range may vary dramatically as the simulation progresses, volume rendering using local transfer functions may not be coherent for all time steps ...

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Multi-GPU Volume Rendering using MapReduce

Jeff A. Stuart, Cheng-Kai Chen, Kwan-Liu Ma, and John D. Owens

In Proceedings of the 1st International Workshop on MapReduce and Its Applications
HPDC 2010
ACM, June, 2010, pp. 841-848

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In this paper we present a multi-GPU parallel volume rendering implementation built using the MapReduce programming model. We give implementation details of the library, including specific optimizations made for our rendering and compositing design. We analyze the theoretical peak performance and bottlenecks for all tasks required and show that our system significantly reduces computation as a bottleneck in the ray-casting phase ...

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Cross-Node Occlusion in Sort-Last Volume Rendering

Stephane Marchesin and Kwan-Liu Ma

In Proceedings of Eurographics Parallel Graphics and Visualization Symposium (EGPGV)
(Accepted for publication)
May, 2010

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In the field of parallel volume rendering, occlusion is a concept which is already widely exploited in order to improve performance. However, when one moves to larger datasets the use of parallelism becomes a necessity, and in that context, exploiting occlusion to speed up volume rendering is not straightforward. In this paper, we propose and detail a new scheme in which the processors exchange occlusion information so as to speed up the rendering by discarding invisible areas ...

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In-Situ Visualization for Large-Scale Combustion Simulations

Hongfeng Yu, Chaoli Wang, Ray w. Grout, Jacqueline H. Chen, and Kwan-Liu Ma

IEEE Computer Graphics and Applications
Volume 30, Number 3, May/June, 2010, pp. 45-57

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As scientific supercomputing moves toward petascale and exascale, in-situ visualization clearly becomes the most cost- effective way to enable scientists to see the full extent of the data generated by their simulations. This is particularly crucial for capturing and understanding highly intermittent transient phenomena, e.g. ignition/extinction events in turbulent combustion. However, integrating the visualization process into the simulation pipeline poses several challenges which have not been fully addressed ...

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A Sketch-Based Interface for Classifying and Visualizing Vector Fields

Jishang Wei, Chaoli Wang, Hongfeng Yu, and Kwan-Liu Ma

In Proceedings of IEEE Pacific Visualization Symposium
March, 2010

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In flow visualization, field lines are often used to convey both global and local structure and movement of the flow. One challenge is to find and classify the representative field lines. Most existing solu- tions follow an automatic approach that generates field lines char- acterizing the flow and arranges these lines into a single picture. In our work, we advocate a user-centric approach to exploring 3D vector fields ...

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Visualizing Field-Measured Seismic Data

Tung-Ju Hsieh, Cheng-Kai Chen, and Kwan-Liu Ma

In Proceedings of IEEE Pacific Visualization Symposium
March, 2010

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This paper presents visualization of field-measured, time-varying multidimensional earthquake accelerograph readings. Direct vol- ume rendering is used to depict the space-time relationships of seismic readings collected from sensor stations in an intuitive way such that the progress of seismic wave propagation of an earthquake event can be directly observed. The resulting visualization reveals the sequence of seismic wave initiation, propagation, attenuation over time, and energy releasing events ...

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Explorable Images for Visualizing Volume Data

Anna Tikhonova, Carlos Correa, and Kwan-Liu Ma

In Proceedings of IEEE Pacific Visualization Symposium
March, 2010

pdf bibtex

We present a technique which automatically converts a small num- ber of single-view volume rendered images of the same 3D data set into a compact representation of that data set. This representation is a multi-layered image, or an explorable image, which enables inter- active exploration of volume data in transfer function space with- out accessing the original data. We achieve this by automatically extracting layers depicted in composited images ...

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

Chaoli Wang, Hongfeng Yu, and Kwan-Liu Ma

IEEE Computer Graphics and Applications
Volume 30, Number 1, January/February, 2010, pp. 59-69

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This paper presents an application-driven approach to compressing large-scale time-varying volume data. Our approach identifies a reference feature to partition the data into space-time blocks, which are compressed with various precisions depending on their association to the feature. Runtime decompression is performed with bit-wise texture packing and deferred filtering. This method achieves high compression rates and interactive rendering while preserving fine details surrounding regions of interest ...