## A Parallel Visualization Pipeline for Terascale Earthquake Simulations (DVD Proceedings)
| This paper presents a parallel visualization pipeline implemented at the Pittsburgh Supercomputing Center (PSC) for studying the largest earthquake simulation ever performed. The simulation employs 100 million hexahedral cells to model 3D seismic wave propagation of the 1994 Northridge earthquake. The time-varying dataset produced by the simulation requires terabytes of storage space. Our solution for visualizing such terascale simulations is based on a parallel adaptive rendering algorithm coupled with a new parallel I/O strategy which effectively reduces interframe delay by dedicating some processors to I/O and preprocessing tasks ... | |

## Visualization for Security
| The widespread use of computers and internet makes computer security an increasingly important problem. Homeland security has also become the top prority of our nation. One basic approach to the security problem is to analyze large data collected from all possible sources. The results of the analysis can help spot suspecious activities and track down known malicious intents. As demonstrated in many other data analysis problems, visualization can be very useful when massive data is involved. ... | |

## Anisotropic Volume Rendering for Extremely Dense, Thin Line Data
| Many large scale physics-based simulations which take place on PC clusters or supercomputers produce huge amounts of data including vector fields. While these vector data such as electromagnetic fields, fluid flow fields, or particle paths can be represented by lines, the sheer number of the lines overwhelms the memory and computation capability of a high-end PC used for visualization. Further, very dense or intertwined lines, rendered with traditional visualization techniques, can produce unintelligible results with unclear depth relationships between the lines and no sense of global structure ... | |

## Visualizing Gyrokinetic Simulations
| The continuing advancement of plasma science is central to realizing fusion as an inexpensive and safe energy source. Gryokinetic simulations of plasmas are fundamental to the understanding of turbulent transport in fusion plasma. This paper discusses the visualization challenges presented by gyrokinetic simulations using magnetic field line following coordinates, and presents an effective solution exploiting programmable graphics hardware to enable interactive volume visualization of 3D plasma flow on a toroidal coordinate system ... | |

## Combining Visual and Automated Data Mining for Near-Real-Time Anomaly Detection and Analysis in BGP
| The security of Internet routing is a major concern because attacks and errors can result in data packets not reaching their intended destination and/or falling into the wrong hands. A key step in improving routing security is to analyze and understand it. In the past, we and other researchers have presented various visual-based, statistical-based, and signature-based methods of analyzing Internet routing data ... | |

## PortVis: A Tool for Port-Based Detection of Security Events
| Most visualizations of security-related network data require large amounts of finely detailed, high-dimensional data. However, in some cases, the data available can only be coarsely detailed because of security concerns or other limitations. How can interesting security events still be discovered in data that lacks important details, such as IP addresses, network security alarms, and labels? In this paper, we discuss a system we have designed that takes very coarsely detailed data—basic, summarized information of the activity on each TCP port during each given hour—and uses ... | |

## Lighting Transfer Functions Using Gradient Aligned Sampling
| An important task in volume rendering is the visualization of boundaries between materials. This is typically accomplished using transfer functions that increase opacity based on a voxel’s value and gradient. Lighting also plays a crucial role in illustrating surfaces. In this paper we present a multi-dimensional transfer function method for enhancing surfaces, not through the variation of opacity, but through the modification of surface shading ... | |

## Visual Data Analysis for Detecting Flaws and Intruders in Computer Network Systems
| Keeping computer and network systems secure and stable requires collecting vast amounts of data and analyzing how the systems perform dynamically. No matter how rigorous a system’s design process, runtime factors can compromise performance. Even network protocols with strong theoretical bases can suffer security flaws and instability when deployed. Furthermore, few systems are designed with perfect security. Intrusion detection and response are thus important components of any computer system. ... | |

## Techniques for Visualizing Time-Varying Volume Data
| Our ability to study and understand complex, transient phenomena is critical to the solution of many scientific and engineering problems. Examples include data from the study of neuron excitement, crack propagation in a material, evolution of a thunderstorm, unsteady flow surrounding an aircraft, seismic reflection from geological strata, and the merging of galaxies. A typical time-varying dataset from a computational fluid dynamics ... | |

## Visualization for Computational Accelerator Physics
| High-energy physics is about the study of the smallest elementary particles, the building blocks of the universe. New discoveries in high-energy physics often lead to fundamental advances in other disciplines such as astronomy, biology, environmental science, materials science, and medicine. Particle accelerators are used in the laboratory by high-energy physicists to study the properties of these particles, how they are created, and how they interact . ... | |

## Data Visualization
| Data visualization has emerged as a new discipline that is about the art and science of using computers to make pictures that elucidate a concept, phenomenon, relationship, or trend hidden in a large quantity of data. By extensively using interactive 3D graphics it is beyond the making of static illustrations or graphs. A strong emphasis of data visualization is thus placed on interactive exploration. ... | |

## I/O Strategies for Parallel Rendering of Large Time-Varying Volume Data
| This paper presents I/O solutions for the visualization of time-varying volume data in a parallel and distributed computing environment. Depending on the number of rendering processors used, our I/O strategies help significantly lower interframe delay by employing a set of I/O processors coupled with MPI parallel I/O support. The targeted application is earthquake modeling using a large 3D unstructured mesh consisting of one hundred millions cells ... | |

## Rendering Complexity in Computer-Generted Pen-and-Ink Illustrations
| We present a method to aid in the generation of pen-and-ink style renderings of complex geometry. Most illustration algorithms focus on rendering a small number of surfaces with as much detail and expression as possible. These methods break down when the scene is composed of many small, overlapping details that are not individually resolvable. We propose a hybrid 2D/3D pipeline that incorporates image processing with the full scene geometry to extract regions which may require special handling ... | |

## A Cluster-Space Visual Interface for Arbitrary Dimensional Classification of Volume Data
| In volume visualization, users typically specify transfer functions to classify the data and assign visual attributes to each material class. Higher-dimensional classication makes it easier to differentiate material classes since more data properties are considered. One of the difculties in using higher-dimensional classication is the absence of appropriate user interfaces. We introduce an intuitive user interface that allows the user to work in the cluster space, which shows the material classes with a set of material widgets, rather than work in the transfer function | |

## High-Quality Lighting and Efficient Pre-Integration for Volume Rendering
| Pre-integrated volume rendering is an effective technique for generating high-quality visualizations. The precomputed lookup tables used by this method are slow to compute and can not include truly pre-integrated lighting due to space constraints. The lighting for pre-integrated rendering is therefore subject to the same sampling artifacts as in standard volume rendering. We propose methods to speed up lookup table generation and minimize lighting artifacts ... | |

## Image Graphs - A Novel Approach to Visual Data Exploration
| For 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
| This 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
| Visualization 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
| This 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
| This 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 ... | |

## R-Tree Retrieval of Unstructured Volume Data for Visualization
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## A Java-Based Testbed for Volume Visualization
| 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 ... | |

## Massively Parallel Volume Rendering
| 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
| 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 ... | |

## Out-of-Core Streamline Visualization on Large Unstructured Meshes
| Most 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 ... | |

## A Scalable Parallel Cell-Projection Volume Rendering Algorithm for Three-Dimensional Unstructured Data
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## 3D Shock Wave Visualization on Unstructured Grids
| 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
| 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
| 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
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## Runtime Volume Visualization for Parallel CFD
| 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
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## Cloud Dispersion Properties in Visualization of Gas and Particle Mixing
| 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
| 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
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## Parallel Volume Ray-Casting for Unstructured-Grid Data on Distributed-Memory Architectures
| 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
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## Interactive Visualization of Multiphase Mixing in Steady-State CFD
| 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
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## A Distributed 3D Navier-Stokes Solver in Express
| 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
| 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
| 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
| 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
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## Virtual Smoke: An Interactive 3D Flow Visualization Technique
| 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
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## Parallel Volume Visualization on Workstations
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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
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## Volume Seedlings
| Recent 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 ... | |

## Direct Numerical Simulation and Visualization of a Three Dimensional Planar Mixing Layer
| 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 ... | |

## Volume Seeds: A Volume Exploration Technique
| Ray-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
| Most 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) ... | |

## A Distributed Algorithm for the Three Dimensional Compressible Navier-Stokes Equations
| ... |