DevLan/vispubs huggingface dataset:
Software Landscapes: Visualizing the Structure of Large Software Systems
Authors: Michael Balzer, Andreas Noack, Oliver Deussen, Claus Lewerentz
Published at EuroVis, 2004

Modern object-oriented programs are hierarchical systems with many thousands of interrelated subsystems. Visualization helps developers to better comprehend these large and complex systems. This paper presents a three-dimensional visualization technique that represents the static structure of object-oriented programs using landscape-like distributions of three-dimensional objects on a two-dimensional plane. The familiar landscape methaphor facilitates intuitive navigation and comprehension. The visual complexity is reduced by adjusting the transparency of object surfaces to the distance of the viewpoint. An approach called Hierarchical Net is proposed for a clear representation of the relationsships between the subsystems.
Superquadric tensor glyphs
Authors: Gordon L. Kindlmann
Published at EuroVis, 2004

Tensor field visualization is a challenging task due in part to the multi-variate nature of individual tensor samples. Glyphs convey tensor variables by mapping the tensor eigenvectors and eigenvalues to the orientation and shape of a geometric primitive, such as a cuboid or ellipsoid. Though widespread, cuboids and ellipsoids have problems of asymmetry and visual ambiguity. Cuboids can display misleading orientation for tensors with underlying rotational symmetry. Ellipsoids differing in shape can be confused, from certain viewpoints, because of similarities in profile and shading. This paper addresses the problems of asymmetry and ambiguity with a new tunable continuum of glyphs based on superquadric surfaces. Superquadric tensor glyphs enjoy the necessary symmetry properties of ellipsoids, while also imitating cuboids and cylinders to better convey shape and orientation, where appropriate. The new glyphs are demonstrated on fields of diffusion tensors from the human brain.
Surface Techniques for Vortex Visualization
Authors: Christoph Garth, Xavier Tricoche, Tobias Salzbrunn, Tom Bobach, Gerik Scheuermann
Published at EuroVis, 2004

This paper presents powerful surface based techniques for the analysis of complex flow fields resulting from CFD simulations. Emphasis is put on the examination of vortical structures. An improved method for stream surface computation that delivers accurate results in regions of intricate flow is presented, along with a novel method to determine boundary surfaces of vortex cores. A number of surface techniques are presented that aid in understanding the flow behavior displayed by these surfaces. Furthermore, a scheme for phenomenological extraction of vortex core lines using stream surfaces is discussed and its accuracy is compared to one of the most established standard techniques.
Techniques for Visualizing Multi-Valued Flow Data
Authors: Timothy Urness, Victoria Interrante, Ellen Longmire, Ivan Marusic, Bharathram Ganapathisubramani
Published at EuroVis, 2004

In this paper we discuss several techniques to display multiple scalar distributions within an image depicting a 2D flow field. We first address how internal contrast and mean luminance can effectively be used to represent a scalar distribution in addition to an underlying flow field. Secondly, we expand upon a current technique to more effectively use luminance ramps over dense streamlines to represent direction of flow. Lastly, we present a new method, based on embossing, to encode the out-of-plane component of a 3D vector field defined over a 2D domain. Throughout this paper, we limit our focus to the visualization of steady flows.
Texture-Based Flow Visualization on Isosurfaces
Authors: Robert S. Laramee, Jürgen Schneider, Helwig Hauser
Published at EuroVis, 2004

Isosurfacing, by itself, is a common visualization technique for investigating 3D vector fields. Applying texturebased flow visualization techniques to isosurfaces provides engineers with even more insight into the characteristics of 3D vector fields. We apply a method for producing dense, texture-based representations of flow on isosurfaces. It combines two well know scientific visualization techniques, namely iso-surfacing and texture-based flow visualization, into a useful hybrid approach. The method is fast and can generate dense representations of flow on isosurfaces with high spatio-temporal correlation at 60 frames per second. The method is applied in the context of CFD simulation data, namely, the investigation of a common swirl flow pattern and the visualization of blood flow.
TimeHistograms for Large, Time-Dependent Data
Authors: Robert Kosara, Fabian Bendix, Helwig Hauser
Published at EuroVis, 2004

Histograms are a very useful tool for data analysis, because they show the distribution of values over a data dimension. Many data sets in engineering (like computational fluid dynamics, CFD), however, are time-dependent. While standard histograms can certainly show such data sets, they do not account for the special role time plays in physical processes and our perception of the world.
 We present TimeHistograms, which are an extension to standard histograms that take time into account. In several 2D and 3D views, the data is presented in different ways that allow the user to understand different aspects of the temporal development of a dimension. A number of interaction techniques are also provided to make best use of the display, and to allow the user to brush in the histograms.
Visual Component Analysis
Authors: Wolfgang Müller 0004, Marc Alexa
Published at EuroVis, 2004

We propose to integrate information visualization techniques with factor analysis. Specifically, a principal direction derived from a principal component analysis (PCA) of the data is displayed together with the data in a scatterplot matrix. The direction can be adjusted to coincide with visual trends in the data. Projecting the data onto the orthogonal subspace allows determining the next direction. The set of directions identified in this way forms an orthogonal space, which represents most of the variation in the data. We call this process visual component analysis (VCA). Furthermore, it is quite simple to integrate VCA with clustering. The user fits poly-lines to the displayed data, and the poly-lines implicitly define clusters. Per-cluster projection leads to the definition of per-cluster components.
Visual Triangulation of Network-Based Phylogenetic Trees
Authors: Ulrik Brandes, Tim Dwyer, Falk Schreiber
Published at EuroVis, 2004

Phylogenetic trees are built by examining differences in the biological traits of a set of species. An example of such a trait is a biological network such as a metabolic pathway, common to all species but with subtle differences in each. Phylogenetic trees of metabolic pathways represent multiple aspects of similarity and hypothetical evolution in a single, yet complex structure that is difficult to understand and interpret. We present a visualization method that facilitates analysis of such structures by presenting multiple coordinated perspectives simultaneously. Each of these perspectives constitutes a useful visualization in its own right, but it is only together that they unfold their full explorative power.
Visualization For Public-Resource Climate Modeling
Authors: J. P. R. B. Walton, D. Frame, D. A. Stainforth
Published at EuroVis, 2004

Climateprediction.net aims to harness the spare CPU cycles of a million individual users' PCs to run a massive ensemble of climate simulations using an up-to-date, full-scale 3D atmosphere-ocean climate model. Although it has many similarities with other public-resource computing projects, it is distinguished by the complexity of its computational task, its system demands and the level of participant interaction, data volume and analysis procedures. For simulations running on individual PCs, there is a requirement for visualizations that are compelling and readily grasped, since most users will be interested in the output from the model, but will have a limited level of scientific experience. This paper describes the design and implementation of these visualizations.
Visualization of anatomic tree structures with convolution surfaces
Authors: Steffen Oeltze, Bernhard Preim
Published at EuroVis, 2004

We present a method for visualizing anatomic tree structures, such as vasculature and bronchial trees based on clinical CT- or MR data. The vessel skeleton as well as the diameter information per voxel serve as input. Our method adheres to these data, while producing smooth transitions at branchings and closed, rounded ends by means of convolution surfaces. We discuss the filter design with respect to irritating bulges, unwanted blending and the correct visualization of the vessel diameter. Similar to related work our method is based on the assumption of a circular cross-section of vasculature. In contrast to other authors we employ implicit surfaces to achieve high quality visualization. The method has been applied to a large variety of anatomic trees and produces good results. The time to construct a geometric model is reduced by means of different bounding volumes and careful choice of parameters for polygonization.
Visualization of Cardio-CT Data on Standard PC Hardware
Authors: Michael Bauer 0002
Published at EuroVis, 2004

In the last years, texture based volume rendering on the PC platform has proven very successful. Many methods that could formerly only be done with software renderers can now be done completely by the graphics hardware. In this paper we present first results of our ongoing work that deals with the visualization of time dependent CT data of the human heart. We compare the drawbacks and benefits of 3D and 2D texture based methods. We also show that a high quality shaded rendering can considerably improve the visual quality. Then we present our results in the area of classification methods, especially using two-dimensional classification. Finally we demonstrate that it is possible to visualize a beating heart using moderately sized time dependent Cardio-CT data.
Visualizing Organisms with Hydraulic Body Parts: A Case Study in Integrating Simulation and Visualization Models
Authors: T. Breiner, Ralf Dörner, Christian Seiler, M. Gudo
Published at EuroVis, 2004

The physical structure of organisms can be modelled as a set of coupled hydraulic entities. The hydropneumatic biosimulation is a methodology that is able to simulate the behavior (like movements) of such organisms on the physical level in a biological correct way. Hydropneumatic simulation heavily relies on visualisation: the simulation model is visually constructed and the simulation results are presented visually to the user. This case study presents an approach, how a visualisation of the results of a hydropneumatic biosimulation can be obtained by integrating the biological simulation model with a Computer Graphics geometry model.
Volume Visualization and Visual Queries for Large High-Dimensional Datasets
Authors: Guido Reina, Thomas Ertl
Published at EuroVis, 2004

We propose a flexible approach for the visualization of large, high-dimensional datasets. The raw, highdimensional data is mapped into an abstract 3D distance space using the FastMap algorithm, which helps, together with other linear preprocessing steps, to make changes to the resulting 3D representation within a few seconds. Thus exploration of such datasets is a less tedious task compared to other techniques. We use volumes with four components to enable the user to brush an attribute selection onto the volume for inspection. We exploit multiple transfer functions for displaying these attributes and also to filter one attribute with values of another. An advantage of this volume sampling approach is that the rendering performance is independent of the dataset size. The drawback of limited resolution can be overcome by providing a linked detail view for a freely selectable portion of space. Examples of the inspection and filtering possibilities using a silvicultural dataset illustrate the strengths of our approach.
A social proxy for distributed tasks: design and evaluation of a working prototype
Authors: Thomas Erickson, Wei Huang, Catalina Danis, Wendy A. Kellogg
Published at CHI, 2004

This paper describes an approach to managing tasks and processes that are distributed across a large number of people. The basic idea is to use a social visualization called a task proxy to create a shared awareness amongst the participants in a task or process. The process awareness provided by the task proxy enables its users to monitor the task state, the states of participants, and to communicate with those in particular states. We describe the concept, a first prototype, its evaluation, and discuss future directions.
Connecting time-oriented data and information to a coherent interactive visualization
Authors: Ragnar Bade, Stefan Schlechtweg, Silvia Miksch
Published at CHI, 2004

In modern intensive care units (ICUs), the medical staff has to monitor a huge amount of high-dimensional and time-oriented data, which needs to be visualized user- and task-specifically to ease diagnosis and treatment planning. Available visual representations, like diagrams or charts neglect the implicit information as well as a-priory or associated knowledge about the data and its meaning (for example, 38.5°C (101.3°F) is moderate fever and 41°C (105.8°F) is critical fever). Another challenge is to provide appropriate interaction techniques to explore and navigate the data and its temporal dimensions. In this context one major challenge is to connect time-oriented data and information to a coherent interactive visualization. In this paper we present different interactive visualization techniques which enable the users to reveal the data at several levels of detail and abstraction, ranging from a broad overview to the fine structure. We will also introduce a time visualization and navigation technique that connects overview+detail, pan+zoom, and focus+context features to one powerful time-browser.
Feeling bumps and holes without a haptic interface: the perception of pseudo-haptic textures
Authors: Anatole Lécuyer, Jean-Marie Burkhardt, Laurent Étienne
Published at CHI, 2004

We present a new interaction technique to simulate textures in desktop applications without a haptic interface. The proposed technique consists in modifying the motion of the cursor on the computer screen - i.e. the Control/Display ratio. Assuming that the image displayed on the screen corresponds to a top view of the texture, an acceleration (or deceleration) of the cursor indicates a negative (or positive) slope of the texture. Experimental evaluations showed that participants could successfully identify macroscopic textures such as bumps and holes, by simply using the variations of the motion of the cursor. Furthermore, the participants were able to draw the different profiles of bumps and holes which were simulated, correctly. These results suggest that our technique enabled the participants to successfully conjure a mental image of the topography of the macroscopic textures. Applications for this technique are: the feeling of images (pictures, drawings) or GUI components (windows' edges, buttons), the improvement of navigation, or the visualization of scientific data.
Studying cooperation and conflict between authors with history flow visualizations
Authors: Fernanda B. Viégas, Martin Wattenberg, Kushal Dave
Published at CHI, 2004

The Internet has fostered an unconventional and powerful style of collaboration: "wiki" web sites, where every visitor has the power to become an editor. In this paper we investigate the dynamics of Wikipedia, a prominent, thriving wiki. We make three contributions. First, we introduce a new exploratory data analysis tool, the history flow visualization, which is effective in revealing patterns within the wiki context and which we believe will be useful in other collaborative situations as well. Second, we discuss several collaboration patterns highlighted by this visualization tool and corroborate them with statistical analysis. Third, we discuss the implications of these patterns for the design and governance of online collaborative social spaces. We focus on the relevance of authorship, the value of community surveillance in ameliorating antisocial behavior, and how authors with competing perspectives negotiate their differences.
3D IBFV: hardware-accelerated 3D flow visualization
Authors: Alexandru C. Telea, Jarke J. van Wijk
Published at Vis, 2003

We present a hardware-accelerated method for visualizing 3D flow fields. The method is based on insertion, advection, and decay of dye. To this aim, we extend the texture-based IBFV technique presented by van Wijk (2001) for 2D flow visualization in two main directions. First, we decompose the 3D flow visualization problem in a series of 2D instances of the mentioned IBFV technique. This makes our method benefit from the hardware acceleration the original IBFV technique introduced. Secondly, we extend the concept of advected gray value (or color) noise by introducing opacity (or matter) noise. This allows us to produce sparse 3D noise pattern advections, thus address the occlusion problem inherent to 3D flow visualization. Overall, the presented method delivers interactively animated 3D flow, uses only standard OpenGL 1.1 calls and 2D textures, and is simple to understand and implement.
A constraint-based technique for haptic volume exploration
Authors: Milan Ikits, J. Dean Brederson, Charles D. Hansen, Christopher R. Johnson 0001
Published at Vis, 2003

We present a haptic rendering technique that uses directional constraints to facilitate enhanced exploration modes for volumetric datasets. The algorithm restricts user motion in certain directions by incrementally moving a proxy point along the axes of a local reference frame. Reaction forces are generated by a spring coupler between the proxy and the data probe, which can be tuned to the capabilities of the haptic interface. Secondary haptic effects including field forces, friction, and texture can be easily incorporated to convey information about additional characteristics of the data. We illustrate the technique with two examples: displaying fiber orientation in heart muscle layers and exploring diffusion tensor fiber tracts in brain white matter tissue. Initial evaluation of the approach indicates that haptic constraints provide an intuitive means or displaying directional information in volume data.
A framework for sample-based rendering with O-buffers
Authors: Huamin Qu, Arie E. Kaufman, Ran Shao, Ankush Kumar
Published at Vis, 2003

We present an innovative modeling and rendering primitive, called the O-buffer, for sample-based graphics, such as images, volumes and points. The 2D or 3D O-buffer is in essence a conventional image or a volume, respectively, except that samples are not restricted to a regular grid. A sample position in the O-buffer is recorded as an offset to the nearest grid point of a regular base grid (hence the name O-buffer). The offset is typically quantized for compact representation and efficient rendering. The O-buffer emancipates pixels and voxels from the regular grids and can greatly improve the modeling power of images and volumes. It is a semi-regular structure which lends itself to efficient construction and rendering. Image quality can be improved by storing more spatial information with samples and by avoiding multiple resamplings and delaying reconstruction to the final rendering stage. Using O-buffers, more accurate multi-resolution representations can be developed for images and volumes. It can also be exploited to represent and render unstructured primitives, such as points, particles, curvilinear or irregular volumes. The O-buffer is therefore a uniform representation for a variety of graphics primitives and supports mixing them in the same scene. We demonstrate the effectiveness of the O-buffer with hierarchical O-buffers, layered depth O-buffers, and hybrid volume rendering with O-buffers.
A frequency-sensitive point hierarchy for images and volumes
Authors: Tomihisa Welsh, Klaus Mueller 0001
Published at Vis, 2003

This paper introduces a method for converting an image or volume sampled on a regular grid into a space-efficient irregular point hierarchy. The conversion process retains the original frequency characteristics of the dataset by matching the spatial distribution of sample points with the required frequency. To achieve good blending, the spherical points commonly used in volume rendering are generalized to ellipsoidal point primitives. A family of multiresolution, oriented Gabor wavelets provide the frequency-space analysis of the dataset. The outcome of this frequency analysis is the reduced set of points, in which the sampling rate is decreased in originally oversampled areas. During rendering, the traversal of the hierarchy can be controlled by any suitable error metric or quality criteria. The local level of refinement is also sensitive to the transfer function. Areas with density ranges mapped to high transfer function variability are rendered at higher point resolution than others. Our decomposition is flexible and can be used for iso-surface rendering, alpha compositing and X-ray rendering of volumes. We demonstrate our hierarchy with an interactive splatting volume renderer, in which the traversal of the point hierarchy for rendering is modulated by a user-specified frame rate.
A multi-resolution data structure for two-dimensional Morse-Smale functions
Authors: Peer-Timo Bremer, Herbert Edelsbrunner, Bernd Hamann, Valerio Pascucci
Published at Vis, 2003

We combine topological and geometric methods to construct a multi-resolution data structure for functions over two-dimensional domains. Starting with the Morse-Smale complex, we construct a topological hierarchy by progressively canceling critical points in pairs. Concurrently, we create a geometric hierarchy by adapting the geometry to the changes in topology. The data structure supports mesh traversal operations similarly to traditional multi-resolution representations.
A novel interface for higher-dimensional classification of volume data
Authors: Fan-Yin Tzeng, Eric B. Lum, Kwan-Liu Ma
Published at Vis, 2003

In the traditional volume visualization paradigm, the user specifies a transfer function that assigns each scalar value to a color and opacity by defining an opacity and a color map function. The transfer function has two limitations. First, the user must define curves based on histogram and value rather than seeing and working with the volume itself. Second, the transfer function is inflexible in classifying regions of interest, where values at a voxel such as intensity and gradient are used to differentiate material, not talking into account additional properties such as texture and position. We describe an intuitive user interface for specifying the classification functions that consists of the users painting directly on sample slices of the volume. These painted regions are used to automatically define high-dimensional classification functions that can be implemented in hardware for interactive rendering. The classification of the volume is iteratively improved as the user paints samples, allowing intuitive and efficient viewing of materials of interest.