IEEE VIS Publication Dataset

The issue of monitoring the execution of asynchronous, distributed algorithms on loosely-coupled parallel processor systems, is important for the purposes of (i) detecting inconsistencies and flaws in the algorithm, (ii) obtaining important performance parameters for the algorithm, and (iii) developing a conceptual understanding of the algorithm's behavior, for given input stimulus, through visualization. For a particular class of asynchronous distributed algorithms that may be characterized by independent and concurrent entities that execute asynchronously on multiple processors and interact with one another through explicit messages, the following reasoning applies. Information about the flow of messages and the activity of the processors may contribute significantly towards the conceptual understanding of the algorithm's behavior and the functional correctness of the implementation. The computation and subsequent display of important parameters, based upon the execution of the algorithm, is an important objective of DIVIDE. For instance, the mean and standard deviation values for the propagation delay of ATM cells between any two given Broadband-ISDN (BISDN) nodes in a simulation of BISDN network under stochastic input stimulus, as a function of time, are important clues to the degree of congestion in the Broadband-ISDN network. Although the execution of the algorithm typically generates high resolution data, often, a coarse-level visual representation of the data may be useful in facilitating the conceptual understanding of the behavior of the algorithm. DIVIDE permits a user to specify a resolution less than that of the data from the execution of the algorithm, which is then utilized to coalesce the data appropriately. Given that this process requires significant computational power, for efficiency, DIVIDE distributes the overall task of visual display into a number of user specified workstations that are configured as a loosely-coupled parallel processor. DIVIDE has been implemented on a heterogeneous network of SUN sparc 1 + , sparc 2, and 3/60 workstations and performance measurements indicate significant improvement over that of a uniprocessor-based visual display

Three dimensional computer models of the anatomy generated from volume acquisitions of computed tomography and magnetic resonance imaging are useful adjuncts to 2D images. This paper describes a system that merges the computer generated 3D models with live video to enhance the surgeon's understanding of the anatomy beneath the surface. The system can be used as a planning aid before the operation and provide additional information during an operation. The application of the system to a brain operation is described

The package described in this paper has been designed for analyzing the data collected in the LEP experiment ALEPH. Its main graphical feature is a deep interplay between the description of the objects manipulated and their relationships, and their graphical representation. The easy access to information through navigation between objects and its display makes possible a thorough study of the events produced by the detector. This has proved to be very powerful in numerous occasions for analyzing data and testing programs. The package provides as well statistical analysis tools and a graphic editor. It is based on the PHIGS graphics standard. It will develop towards a more elaborate usage of the data structure in particular in the geometrical representations and towards object oriented languages to overcome some heaviness linked to the use of Fortran

An algorithm for rapid computation of Richards's smooth molecular surface is described. The entire surface is computed analytically, triangulated, and displayed at interactive rates. The faster speeds for our program have been achieved by algorithmic improvements, paralleling the computations, and by taking advantage of the special geometrical properties of such surfaces. Our algorithm is easily parallelable and it has a time complexity of O (k log k) over n processors, where n is the number of atoms of the molecule and k is the average number of neighbors per atom

Volume rendering has been proposed as a useful tool for extracting information from large datasets, where non-visual analysis alone may not be feasible. The scale of these applications implies that data management is an important issue that needs to be addressed. Most volume rendering algorithms, however, process data in raw, uncompressed form. In previous work, we introduced a compressed volume format that may be volume rendered directly with minimal impact on rendering time. In this paper, we extend these ideas to a new volume format that not only reduces storage space and transmission time, but is designed for fast volume rendering as well. The volume dataset is represented as indices into a small codebook of representative blocks. With the data structure, volume shading calculations need only be performed on the codebook and image generation is accelerated by reusing precomputed block projections

The features of greatest interest in ocean modeling in the Gulf of Mexico and along the Gulf Stream are the fronts and eddies. Resolving, modeling, and tracking these eddies over time is of great importance for climatological studies and economic advancement. In this paper we present a novel technique for automatically locating, contouring, and tracking oceanic features such as eddies and fronts. The models and resultant visualizations exhibit excellent correlation with observed data

Most of the current dataflow visualization systems are based on coarse-grain dataflow computing models. In this paper we propose a fine-grain dataflow model that takes advantage of data locality properties of many visualization algorithms. A fine-grain module works on small chunks of data one at a time by keeping a dynamically adjusted moving window on the input data stream. It is more memory efficient and has the potential of handling very large data sets without taking up all the memory resources. Two popular visualization algorithms, an iso-surface extraction algorithm and a volume rendering algorithm, are implemented using the fine-grain model. The performance measurements showed faster speed, reduced memory usage, and improved CPU utilization over a typical coarse-grain system

Flow volumes are the volumetric equivalent of stream lines. They provide more information about the vector field being visualized than do stream lines or ribbons. Presented is an efficient method for producing flow volumes, composed of transparently rendered tetrahedra, for use in an interactive system. The problems of rendering, subdivision, sorting, composing artifacts, and user interaction are dealt with. Efficiency comes from rendering only the volume of the smoke, and using hardware texturing and compositing

Texture mapping is normally used to convey geometric detail without adding geometric complexity. This paper introduces Boolean textures, a texture mapping technique that uses implicit functions to generate texture maps and texture coordinates. These Boolean textures perform clipping during a renderer's scan conversion step. Any implicit function is a candidate Boolean texture clipper. The paper describes how to use quadrics as clippers. Applications from engineering and medicine illustrate the effectiveness of texture as a clipping tool

An algorithm is presented which describes an application independent method for reducing the number of polygonal primitives required to faithfully represent an object. Reducing polygon count without a corresponding reduction in object detail is important for: achieving interactive frame rates in scientific visualization, reducing mass storage requirements, and facilitating the transmission of large, multi-timestep geometric data sets. This paper shows how coplanar and nearly coplanar polygons can be merged into larger complex polygons and re-triangulated into fewer simple polygons than originally required. The notable contributions of this paper are: (1) a method for quickly grouping polygons into nearly coplanar sets, (2) a fast approach for merging coplanar polygon sets and, (3) a simple, robust triangulation method for polygons created by 1 and 2. The central idea of the algorithm is the notion of treating polygonal data as a collection of segments and removing redundant segments to quickly form polygon hulls which represent the merged coplanar sets

Visualization has proved an efficient tool in the understanding of large data sets in computational science and engineering. There is growing interest today in the development of problem solving environments which integrate both visualization and the computational process which generates the data. The GRASPARC project has looked at some of the issues involved in creating such an environment. An architecture is proposed in which tools for computation and visualization can be embedded in a framework which assists in the management of the problem solving process. This framework has an integral data management facility which allows an audit trail of the experiments to be recorded. This design therefore allows not only steering but also backtracking and more complicated problem solving strategies. A number of demonstrator case studies have been implemented

HyperSlice is a new method for the visualization of scalar functions of many variables. With this method the multi-dimensional function is presented in a simple and easy to understand way in which all dimensions are treated identically. The central concept is the representation of a multi-dimensional function as a matrix of orthogonal two-dimensional slices. These two-dimensional slices lend themselves very well to interaction via direct manipulation, due to a one to one relation between screen space and variable space. Several interaction techniques, for navigation, the location of maxima, and the use of user-defined paths, are presented

Streamlines and stream surfaces are well known techniques for the visualization of fluid flow. For steady velocity fields, a streamline is the trace of a particle, and a stream surface is the trace of a curve. Here a new method is presented for the construction of stream surfaces. The central concept is the representation of a stream surface as an implicit surface f (x) = C. After the initial calculation of f a family of stream surfaces can be generated efficiently by varying C. The shapes of the originating curves are defined by the value of f at the boundary. Two techniques are presented for the calculation of f: one based on solving the convection equation, the other on backward tracing of the trajectories of grid points. The flow around objects is discussed separately. With this method irregular topologies of the originating curves and of the stream surfaces can be handled easily. Further, it can also be used for other visualization techniques, such as time surfaces and stream volumes. Finally, an effective method for the automatic placement of originating curves is presented

This paper introduces a novel representation, called the InfoCrystal, that can be used as a visualization tool as well as a visual query language to help users search for information. The InfoCrystal visualizes all the possible relationships among N concepts. Users can assign relevance weights to the concepts and use thresholding to select relationships of interest. The InfoCrystal allows users to specify Boolean as well as vector-space queries graphically. Arbitrarily complex queries can be created by using the InfoCrystals as building blocks and organizing them in a hierarchical structure. The InfoCrystal enables users to explore and filter information in a flexible, dynamic and interactive way

Shading is an effective exploratory visualization tool widely used in scientific visualization. Interactive, or close to interactive, shading of images offers significant benefit, but is generally too computationally expensive for graphics workstations. A novel method for providing interactive diffuse and specular shading capability on low-cost graphics workstations is described. Application to digital elevation models, iso-surfaces in volumetric images, and color-coded aspect maps are illustrated and an analysis of artifacts, and of ways of minimizing artifacts, is given

Making accurate computer graphics representations of surfaces and volumes (2-manifolds and 3-manifolds) embedded in four-dimensional space typically involves complex and time-consuming computations. In order to make simulated worlds that help develop human intuition about the fourth dimensions, we need techniques that permit real-time, interactive manipulation of the most sophisticated depictions available. We propose the following new methods that bring us significantly closer to this goal: an approach to high-speed 4D illuminated surface rendering incorporating 4D shading and occlusion coding; a procedure for rapidly generating 2D screen images of tessellated 3-manifolds illuminated by 4D light. These methods are orders of magnitude faster than previous approaches, enabling the real-time manipulation of high-resolution 4D images on commercial graphics hardware

MRIVIEW is a software system that uses image processing and visualization to provide neuroscience researchers with an integrated environment for combining functional and anatomical information. Key features of the software include semi-automated segmentation of volumetric head data and an interactive coordinate reconciliation method which utilizes surface visualization. The current system is a precursor to a computational brain atlas. We describe features this atlas will incorporate, including methods under development for visualizing brain functional data obtained from several different research modalities

This paper is aimed at the exploratory visualization of networks where there is a strength or weight associated with each link, and makes use of any hierarchy present on the nodes to aid the investigation of large networks. It describes a method of placing nodes on the plane that gives meaning to their relative positions. The paper discusses how linking and interaction principles aid the user in the exploration. Two examples are given; one of electronic mail communication over eight months within a department, another concerned with changes to a large section of a computer program

Visualization of events in high energy physics is an important tool to check hard- and software and to generate pictures for presentation purposes. The radial pattern of all events suggests the use of predefined projections, especially p/Z and Y/X. The representation can be improved by a "fish-eye" transformation and by angular projections, which produce straight track patterns and allow extensive magnifications. Three dimensional data of radial structure are best displayed in the 3D V-Plot, which has optimal track separation and presents all relevant information in a clear way

Digital filtering is a crucial operation in volume reconstruction and visualization. Lowpass filters are needed for subsampling and minification. Interpolation filters are needed for registration and magnification, and to compensate for geometric distortions introduced by scanners. Interpolation filters are also needed in volume rendering for ray-casting and slicing. In this paper, we describe a method for digital filter design of interpolation filters based on weighted Chebyshev minimization. The accuracy of the resulting filters are compared with some commonly used filters defined by piecewise cubic polynomials. A significant finding of this paper is that although piecewise cubic interpolation has some computational advantages and may yield visually satisfactory results for some data, other data result in artifacts such as blurring. Furthermore, piecewise cubic filters are inferior for operations such as registration. Better results are obtained by the filters derived in this papers at only small increases in computation