Publications
Image Graphs - A Novel Approach to Visual Data Exploration
Kwan-Liu MaIn Proceedings of IEEE Visualization 1999 Conference
October, 1999, pp. 81-88For types of data visualization where the cost of producing images is high, and the relationship between the rendering parameters and the image produced is less than obvious, a visual representation of the exploration process can make the process more efficient and effective. Image graphs represent not only the results but also the process of data visualization. Each node in an image graph consists of an image and the corresponding visualization parameters used to produce it ...
A Fast Volume Rendering Algorithm for Time-Varying Fields Using a Time-Step Partitioning (TSP) Tree
Han-Wei Shen, Ling-Jen Chiang, and Kwan-Liu MaIn Proceedings of IEEE Visualization 1999 Conference
October, 1999, pp. 371-378This paper presents a fast volume rendering algorithm for timevarying fields. We propose a new data structure, called Time-Space Partitioning (TSP) tree, that can effectively capture both the spatial and the temporal coherence from a time-varying field. Using the proposed data structure, the rendering speed is substantially improved. In addition, our data structure helps to maintain the memory access locality and to provide the sparse data traversal so that our algorithm becomes suitable for large-scale out-of-core applications ...
Visualization Case Studies: Drawing a Roadmap for Future Visualization
Kwan-Liu Ma and Frits H. PostIEEE Computer Graphics and Applications
Volume 19, Number 5, September/October, 1999, pp. 48-49Visualization has become an indispensable tool for scientific researchers to understand their data ånd communicate their findings. Appropriate visualization tools often lead scientists to new insights more quickly. Today, both instrument and computing technologies advance quickly, enhancing scientists' capability to study problems of increasing scale and complexity. ...
Parallel Visualization of Large-scale Aerodynamics Calculations: A Case Study on the Cray T3E
Kwan-Liu Ma and Thomas W. CrockettIn Proceedings of IEEE Parallel Visualization and Graphics Symposium
October, 1999, pp. 15-20This paper reports the performance of a parallel volume rendering algorithm for visualizing a largescale unstructured-grid dataset produced by a three-dimensional aerodynamics simulation. This dataset, containing over 18 million tetrahedra, allows us to extend our performance results to a problem which is more than 30 times larger than the one we examined previously. This high resolution dataset also allows us to see fine, threedimensional features in the flow field ...
Parallel Rendering of 3D AMR Data on the SGI/Cray T3E
Kwan-Liu MaIn Proceedings of the 7th Symposium on the Frontiers of Massively Parallel Computation
February, 1999, pp. 138-145This paper describes work-in-progress on developing parallel visualization strategies for 3D Adaptive Mesh Refinement (AMR) data. AMR is a simple and powerful tool for modeling many important scientific and engineering problems. However, visualization tools for 3D AMR data are not generally available. Converting AMR data onto a uniform mesh would result in high storage requirements, and rendering the uniform-mesh data on an average graphics workstation can be painfully slow if not impossible ...
Out-of-Core Streamline Visualization on Large Unstructured Meshes
Shyh-Kuang Ueng, Christopher Sikorski, and Kwan-Liu MaIEEE Transactions on Visualization and Computer Graphics
Volume 3, Number 4, October-December, 1997, pp. 370-380Most scientific visualization software systems have been designed for data that can fit into the physical memory of a single workstation. For many scientific applications, data at the desirable resolution can easily overwhelm the memory capacity of the scientist’s desktop workstation. This is particularly true for data obtained from three-dimensional aerodynamics calculations, where very fine unstructured tetrahedral meshes are needed to model arbitrarily complex configurations, such as an airplane ...
Extracting Feature Lines from 3D Unstructured Grids
Kwan-Liu Ma and Victoria InterranteIn Proceedings of Visualization 1997 Conference and IEEE Computer Society
October, 1997, pp. 285-292The paper discusses techniques for extracting feature lines from three-dimensional unstructured grids. The twin objectives are to facilitate the interactive manipulation of these typically very large and dense meshes, and to clarify the visualization of the solution data that accompanies them. The authors describe the perceptual importance of specific viewpoint-dependent and view-independent features, discuss the relative advantages and disadvantages of several alternative algorithms for identifying these features (taking into consideration both local and global criteria), and demonstrate the results of these methods on a variety of different data sets ...
3D Visualization of Unsteady 2D Airplane Wake Vortices
Kwan-Liu Ma and Zhongquan Charlie ZhengIn Proceedings of Visualization 1994 Conference
October, 1994, pp. 124-130Air flowing around the wing tips of an airplane forms horizontal tornado-like vortices that can be dangerous to following aircraft. The dynamics of such vortices, including ground and atmospheric effects, can be predicted by numerical simulation, allowing the safety and capacity of airports to be improved. We introduce three-dimensional techniques for visualizing time-dependent, two-dimensional wake vortex computations, and the hazard strength of such vortices near the ground ...
Volume Seedlings
Michael Cohen, James Painter, Mihir Mehta, and Kwan-Liu MaIn Proceedings of the 1992 ACM Symposium on Interactive 3D Graphics
1992, pp. 139-145Recent advances in software and hardware technology have made direct ray-traced volume rendering of 3-d scalar data a feasible and effective method for imaging of the data’s contents. The time costs of these rendering techniques still do not permit full interaction with the data, and all of the parameters effecting the resulting images. This paper presents a set of real-time interaction techniques which have been developed to permit exploration of a volume data set ...
Volume Seeds: A Volume Exploration Technique
Kwan-Liu Ma, Michael F. Cohen, and James S. PainterThe Journal of Visualization and Computer Animation
Volume 2, Number 4, 1991, pp. 135-140Ray-traced volume rendering has been shown to be an effective method for visualizing 3D scalar data. However, with currently available workstation technology, interactive volume exploration using conventional volume rendering is still too slow to be attractive. This paper describes an enhanced volume rendering method which allows interactive changes of rendering parameters such as colour and opacity maps. An innovative technique is provided which allows the user to plant a seed in the volume to rapidly modify local shading parameters ...
TICL - A Type Inference System for Common Lisp
Kwan-Liu Ma and R. KesslerIn Software Practice and Experience
Volume 20, Number 6, January, 1990, pp. 593-623Most current Common Lisp compilers generate more efficient code when supplied with data type information. However, in keeping with standard Lisp programming style, most programmers are reluctant to provide type information; they simply allow the run-time type system to manage the data types accordingly. To fill this gap, we have designed and implemented a type inference system for Common Lisp (TICL) ...
R-Tree Retrieval of Unstructured Volume Data for Visualization
Scott T. Leutenegger and Kwan-Liu MaDIMACS Series in Discrete Mathematics and Theoretical Computer Science
Volume 50, 1999, pp. 279-291
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A Java-Based Testbed for Volume Visualization
Kwan-Liu MaIn Proceedings of the Workshop on Computer Graphics and Virtual Reality
December, 1998, pp. 68-75
This paper describes a Java-based visualization software testbed for experimenting with new ideas and rendering codes, as well as approaches for remote and collaborative visualization. This system allows visualization across the Internet from a web browser supporting the Java language. We also address issues in designing more intuitive ...
A Graph-based Interface for Representing Volume Visualization Results
James Patten and Kwan-Liu MaIn Proceedings of Graphics Interface '98
June, 1998, pp. 117-124
This paper discusses a graph based user interface for representing the results of the volume visualization process. As images are rendered, they are connected to other images in a graph based on their rendering parameters. The user can take advantage of the information in this graph to understand how certain rendering parameter changes affect a dataset, making the visualization process more efficient. ...
Massively Parallel Volume Rendering
Kwan-Liu MaIn Proceedings of ACM SIGGRAPH 1998 and 25th International Conference on Computer Graphics and Interactive Technologies
1998, pp. 29-53
We are developing techniques for massively parallel volume rendering, examining primarily the techniques of algorithms on general parallel computers. Research involves the use of the UCSC 4096 processor MasPar MP-2 and numerous workstations. Recent NSF funding shall provide a very high performance visualization platform on which we shall also do research. Important research topics are: what is the maximum performance attainable for volumetric visualization on any given parallel computer? What is the optimal algorithm for volume visualization for a general model of computation? Which interactivity features provide capabilities that allow new results to be discovered with volumetric data? ...
A Parallel Pipelined Renderer for Time-Varying Volume Data
Tzi-cker Chiueh and Kwan-Liu MaIn Proceedings of the 1997 International Symposium on Parallel Architectures, Algorithms and Networks (ISPAN)
December, 1997, pp. 9-15
This paper presents a strategy for efficiently rendering time-varying volume data on a distributed-memory parallel computer. Time-varying volume data take large storage space and visualizing them requires reading large files continuously or periodically throughout the course of the visualization process. Instead of using all the processors to collectively render one volume at a time, a pipelined rendering process is proposed by partitioning processors into groups to render multiple volumes concurrently ...
A Scalable Parallel Cell-Projection Volume Rendering Algorithm for Three-Dimensional Unstructured Data
Kwan-Liu Ma and T. CrockettIn Proceedings of 1997 Symposium on Parallel Rendering, ACM SIGGRAPH, and IEEE Computer Society
1997, pp. 95-104
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3D Shock Wave Visualization on Unstructured Grids
Kwan-Liu Ma, John Van Rosendale, and Willem VermeerIn Proceedings of Symposium on Volume Visualization
October, 1996, pp. 87-94
A critical issue in understanding high speed flows is the study of shock waves. This paper summarizes our research on techniques for the detection and visualization of shock waves occuring in simulations of threedimensional flows on unstructured grids. Detection algorithms based on Mach number, density gradient and directional derivatives are compared using a data set from calculations of a transonic flow with a weak double shock around an airfoil ...
Visualizing Vector Fields Using Line Integral Convolution and Dye Advection
Han-Wei Shen, Christopher R. Johnson, and Kwan-Liu MaIn Proceedings of Symposium on Volume Visualization
October, 1996, pp. 63-69
We present local and global techniques to visualize three-dimensional vector field data. Using the Line Integral Convolution (LIC) method to image the global vector field, our new algorithm allows the user to introduce colored “dye” into the vector field to highlight local flow features. A fast algorithm is proposed that quickly recomputes the dyed LIC images. In addition, we introduce volume rendering methods that can map the LIC texture on any contour surface and/or translucent region defined by additional scalar quantities, and can follow the advection of colored dye throughout the volume ...
Efficient Streamline, Steamribbon, and Streamtube Constructions on Unstructured Grids
Shyh-Kuang Ueng, Christopher Sikorski, and Kwan-Liu MaIEEE Transactions on Visualization and Computer Graphics
Volume 2, Number 2, June, 1996, pp. 100-110
Streamline construction is one of the most fundamental techniques for visualizing steady flow fields. Streamribbons and streamtubes are extensions for visualizing the rotation and the expansion of the flow. The paper presents efficient algorithms for constructing streamlines, streamribbons, and streamtubes on unstructured grids. A specialized Runge-Kutta method is developed to speed up the tracing of streamlines. Explicit solutions are derived for calculating the angular rotation rates of streamribbons and the radii of streamtubes ...
Flow Visualization Using LIC-Based Dye Advection
Kwan-Liu MaICASE Research Quarterly
Volume 5, Number 3, 1996, pp. 2-3
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Runtime Volume Visualization for Parallel CFD
Kwan-Liu MaIn Proceedings of the Parallel Computational Fluid Dynamics 1995 Conference
October, 1995, pp. 307-314
This paper discusses some aspects of the design of a data distributed, massively parallel volume rendering library for runtime visualization of parallel computational fluid dynamics simulations in a message-passing environment. Unlike the traditional scheme in which visualization is a postprocessing step, the rendering is done in place on each node processor. Computational scientists who run large-scale simulations on a massively parallel computer can thus perform interactive monitoring of their simulations ...
Volume Visualization of Airplane Wake Vortices
Kwan-Liu Ma and Zhongquan Charlie ZhengIn Proceedings of the 7th International Symposium on Flow Visualization
September, 1995, pp. 586-591
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Cloud Dispersion Properties in Visualization of Gas and Particle Mixing
Kwan-Liu Ma, Philip Smith, and Sandeep JainIn Proceedings of the 7th International Symposium on Flow Visualization
September, 1995, pp. 572-577
It is shown that cloud dispersion concepts can be used to visualize the dispersion and mixing of both massless or fluid particles and inertial particle systems. The cloud can interact with surfaces by sticking or rebounding the particles within the cloud. This method provides rapid feedback on mixing and dispersion processes and is computationally efficient enough to be interactive. Further insight can be obtained by using volume rendering so that the cloud content can also be visualized, not just the exterior surface of the cloud ...
Fast Algorithms for Visualizing Fluid Motion in Steady Flow on Unstructured Grids
Shyh-Kuang Ueng, Christopher Sikorski, and Kwan-Liu MaIn Proceedings of Visualization 1995 Conference
August, 1995, pp. 313-319
The plotting of streamlines is an effective way of visualizing fluid motion in steady flows. Additional information about the flowfield, such as local rotation and expansion, can be shown by drawing in the form of a ribbon or tube. In this paper, we present efficient algorithms for the construction of streamlines, streamribbons and streamtubes on unstructured grids. A specialized version of the Runge-Kutta method has been developed to speed up the integration of particle pathes ...
Parallel Volume Rendering
Kwan-Liu MaICASE Research Quarterly
Volume 4, Number 1, 1995, pp. 8-9
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Parallel Volume Ray-Casting for Unstructured-Grid Data on Distributed-Memory Architectures
Kwan-Liu MaIn Proceedings of the 1995 Parallel Rendering Symposium, IEEE Computer Society, and ACM SIGGRAPH
1995, pp. 23-30
As computing technology continues to advance, computational modeling of scientific and engineering problems produces data of increasing complexity: large in size and unstructural in shape. Volume visualization of such data is a challenging problem. This paper proposes a distributed parallel solution that makes ray-casting volume rendering of unstructured-grid data practical. Both the data and the rendering process are distributed among processors ...
Visualization of Particles and Gas Mixing
Kwan-Liu Ma and Philip SmithInternational Journal of CAD/CAM and Computer Graphics
Volume 10, Number 3, 1995, pp. 273-289
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Interactive Visualization of Multiphase Mixing in Steady-State CFD
Kwan-Liu Ma and Phillip SmithIn Proceedings of AIAA 32nd Aerospace Sciences Meeting and Exhibit
January, 1994
This paper describes an interactive technique for the visualization of the basic physical process of stochastic dispersion and mixing from steadystate CFD calculations. The mixing of massless particles or inertial particles is visualized by transforming the vector field from a traditionally Eulerian reference frame into a Lagrangian reference frame. Groups of articles are traced through the vector field for the mean path as well as their statistic ...
Parallel Volume Rendering Using Binary-Swap Compositing
Kwan-Liu Ma, James Painter, Charles Hansen, and Michael KroghIEEE Computer Graphics and Applications
Volume 14, Number 4, July, 1994, pp. 59-68
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A Distributed 3D Navier-Stokes Solver in Express
Kwan-Liu Ma and Christopher SikorskiEnergy and Fuels
Volume 7, November, 1993, pp. 897-901
The Navier-Stokes equations are central to applied scientific research. The complete set of threedimensional Navier-Stokes equations is very complex and thus requires a substantial amount of computer time as well as memory in order to obtain an accurate solution. The scalability in both processing power and memory space of distributed-memory parallel computers give promise of solving large scale three-dimensional scientific problems based on these equations ...
Cloud Tracing in Convection-Diffusion Systems
Kwan-Liu Ma and Philip SmithIn Proceedings of Visualization 1993 Conference
October, 1993, pp. 253-259
The paper describes a highly interactive method for computer visualization of simultaneous three-dimensional vector and scalar flow fields in convection-diffusion systems. This method allows a computational fluid dynamics user to visualize the basic physical process of dispersion and mixing rather than just the vector and scalar values computed by the simulation. It is based on transforming the vector field from a traditionally Eulerian reference frame into a Lagrangian reference frame ...
A Data Distributed, Parallel Algorithm for Ray-traced Volume Rendering
Kwan-Liu Ma, James Painter, Charles Hansen, and Michael KroghIn Proceedings of the 1993 Parallel Rendering Symposium, IEEE Computer Society and ACM SIGGRAPH
October, 1993, pp. 15-22
This paper presents a divide-and-conquer ray-traced volume rendering algorithm and a parallel image compositing method, along with their implementation and performance on the Connection Machine CM-5, and networked workstations. This algorithm distributes both the data and the computations to individual processing units to achieve fast, high-quality rendering of high-resolution data. The volume data, once distributed, is left intact. The processing nodes perform local ray tracing of their subvolume concurrently ...
Distributed Combustion Simulations
Christopher Sikorski and Kwan-Liu MaEnergy and Fuels
Volume 7, Number 6, 1993, pp. 902-905
This paper reports research in progress. Two types of domain decomposition have been used in distributed computing with networked workstations for the numerical modeling of full-scale utility boilers. The numerical model is a three-dimensional combustion code that couples turbulent computational fluid dynamics with the chemical reaction process and the radiative heat transfer. Two approaches, here called microscale parallelism and macroscale parallelism, are proposed to study the intrinsic parallelism of typical combustion simulations ...
Interactive Visualization of 3D Fluid Flow
Kwan-Liu MaICASE Research Quarterly
Volume 2, Number 3, 1993, pp. 6-7
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Virtual Smoke: An Interactive 3D Flow Visualization Technique
Kwan-Liu Ma and Philip SmithIn Proceedings of Visualization 1992 Conference
October, 1992, pp. 46-53
A technique is given for computer visualization of simultaneous three-dimensional vector and scalar fields such as velocity and temperature in reacting fluid flow fields. The technique, which is called Virtual Smoke, simulates the use of colored smoke for experimental gaseous fluid flow visualization. However, it is noninvasive and can animate, in particular, the dynamic behaviors of steady-state or instantaneous flow fields obtained from numerical simulations ...
A Distributed Solution and Visualization for 3D Flow Simulation
Kwan-Liu Ma and Christopher SikorskiIn Proceedings of 5th SIAM Conference on Parallel Processing for Scientific Computing
March, 1992, pp. 287-294
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Parallel Volume Visualization on Workstations
Kwan-Liu Ma and James PainterInternational Journal of Systems and Applications in Computer Graphics
Volume 17, Number 1, 1992, pp. 31-38
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Comparison of Maximum Intensity Projection and Volume Rendering Algorithms for Evaluation of Renal Artery Anatomy in Patients with Abdominal Aortic Aneurysm
A. Sanderson, James Painter, Michael Cohen, Kwan-Liu Ma, Mihir Mehta, and F. MillerIn Proceedings of the 78th Scientific Assembly of the Radiological Soceity of North America
1992
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Direct Numerical Simulation and Visualization of a Three Dimensional Planar Mixing Layer
Randy Clarksean and Kwan-Liu MaIn Proceedings of 1991 AIAA 10th Computational Fluid Dynamics Conference
June, 1991, pp. 981-984
The coupling of the direct numerical simulation and visualization is useful because of the insight it provides into the development and formation of structures within the flowfield. The use of a volume-rendering technique for the visualization of a three-dimensional planar mixing layer is discussed. Graphical data in the form of color 'snapshots' and a video are presented to demonstrate the use of the volume-rendering method as a better way to understand the physics of turbulent flow ...
A Distributed Algorithm for the Three Dimensional Compressible Navier-Stokes Equations
Kwan-Liu Ma and Christopher SikorskiTransputer Research and Applications
Volume 4, 1990, pp. 46-56
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