DevLan/vispubs huggingface dataset:
Speech and Gesture Multimodal Control of a Whole Earth 3D Visualization Environment
Authors: David M. Krum, Olugbenga Omoteso, William Ribarsky, Thad Starner, Larry F. Hodges
Published at EuroVis, 2002

A growing body of research shows several advantages to multimodal interfaces including increased expressiveness, flexibility, and user freedom. This paper investigates the design of such an interface that integrates speech and hand gestures. The interface has the additional property of operating relative to the user and can be used while the user is in motion or standing at a distance from the computer display. The paper then describes an implementation of the multimodal interface for a whole Earth 3D visualization which presents navigation interface challenges due to the large magnitude of scale and extended spaces that are available. The characteristics of the multimodal interface are examined, such as speed, recognizability of gestures, ease and accuracy of use, and learnability under likely conditions of use. This implementation shows that such a multimodal interface can be effective in a real environment and sets some parameters for the design and use of such interfaces.
Statistical Computation of Salient ISO-Values
Authors: Shivaraj Tenginakai, Raghu Machiraju
Published at EuroVis, 2002

Detection of the salient iso-values in a volume dataset is often the first step towards its exploration. An error-and-trail approach is often used; new semi-automatic techniques either make assumptions about their data [4] or present multiple criteria for analysis. Determining if a dataset satisfies an algorithm's assumptions, or the criteria to be used in an analysis are both non-trivial tasks. The use of a dataset's statistical signatures, local higher order moments (LHOMs), to characterize its salient iso-values was presented in [10]. In this paper we propose a computational algorithm that uses LHOMs for expedient estimation of salient iso-values. As LHOMs are model independent statistical signatures our algorithm does not impose any assumptions on the data. Further, the algorithm has a single criterion for characterization of the salient iso-values, and the search for this criterion is easily automated. Examples from medical and computational domains are used to demonstrate the effectiveness of the proposed algorithm.
Useful Properties of Semantic Depth of Field for Better F+C Visualization
Authors: Robert Kosara, Silvia Miksch, Helwig Hauser
Published at EuroVis, 2002

This paper presents the results of a thorough user study that was performed to assess some features and the general usefulness of Semantic Depth of Field (SDOF). Based on these results, concrete hints are given on how SDOF can be used for visualization. SDOF was found to be a very effective means for guiding the viewer's attention and for giving him or her a quick overview of a data set. It can also very quickly be perceived, and therefore provides an efficient visual channel.Semantic Depth of Field is a focus+context (F+C) technique that uses blur to point the user to the most relevant objects. It was inspired by the depth of field (DOF) effect in photography, which serves a very similar purpose.
View-Dependent Multiresolution Splatting of Non-Uniform Data
Authors: Justin Jang, William Ribarsky, Christopher D. Shaw, Nickolas Faust
Published at EuroVis, 2002

This paper develops an approach for the splat-based visualization of large scale, non-uniform data. A hierarchical structure is generated that permits detailed treatment at the leaf nodes of the non-uniform distribution. A set of levels of detail (LODs) are generated based on the levels of the hierarchy. These yield two metrics, one in terms of the spatial extent of the bounding box containing the splat and one in terms of the variation of the scalar field over this box. The former yields a view-dependent choice of LODs while the latter yields a view-independent LOD based on the field variation. To show the utility of this general approach it is applied to a set of application data for a whole earth environment and some test data. Performance results are given.
Viewpoint Entropy: A New Tool for Obtaining Good Views of Molecules
Authors: Pere-Pau Vázquez, Miquel Feixas, Mateu Sbert, Antoni Llobet
Published at EuroVis, 2002

The computation of good viewpoints is important in several fields: computer graphics, removal of degeneracies in computational geometry, robotics, graph drawing, etc. However, in areas such as computer graphics there is no consensus on what a good viewpoint means and, consequently, each author uses his or her own definition according to the requirements of the application. In this paper we present a formal measure strongly based on Information Theory, viewpoint entropy, that can be applied to certain problems of Computer Graphics such as automatic exploration of objects or scenes and Scene Understanding. We also define a new measure, the orthogonal frustum entropy, in order to fulfill the requirements needed to visualize molecules. We design an algorithm that makes use of graphics hardware to accelerate computation, and whose complexity depends mainly on the number of views we want to analyze. Computation of good views of molecules is useful for molecular scientists, a field which includes practitioners from Crystallography, Chemistry, and Biology.
Visualization of Bibliographic Networks with a Reshaped Landscape Metaphor
Authors: Ulrik Brandes, Thomas Willhalm
Published at EuroVis, 2002

We describe a novel approach to visualize bibliographic networks that facilitates the simultaneous identification of clusters (e.g., topic areas) and prominent entities (e.g., surveys or landmark papers). While employing the landscape metaphor proposed in several earlier works, we introduce new means to determine relevant parameters of the landscape. Moreover, we are able to compute prominent entities, clustering of entities, and the landscape's surface in a surprisingly simple and uniform way. The effectiveness of our network visualizations is illustrated on data from the graph drawing literature.
Visualization of Large Web Access Data Sets
Authors: Ming C. Hao, Pankaj K. Garg, Umeshwar Dayal, Vijay Machiraju, Daniel Cotting
Published at EuroVis, 2002

Many real-world e-service applications require analyzing large volumes of transaction data to extract web access information. This paper describes Web Access Visualization (WAV) a system that visually associates the affinities and relationships of clients and URLs for large volumes of web transaction data. To date, many practical research projects have shown the usefulness of a physics-based mass-spring technique to layout data items with close relationships onto a graph. The WAV system: (1) maps transaction data items (clients, URLs) and their relationships to vertices, edges, and positions on a 3D spherical surface; (2) encapsulates a physics-based engine in a visual data analysis platform; and (3) employs various content sensitive visual techniques - linked multiple views, layered drill-down, and fade in/out - for interactive data analysis. We have applied this system to a web application to analyze web access patterns and trends. The web service quality has been greatly benefited from using the information provided by WAV.
Visualizing and Investigating Multidimensional Functions
Authors: Selan R. dos Santos, Ken W. Brodlie
Published at EuroVis, 2002

This paper addresses the problem of visualizing multidimensional scalar functions. These functions are often encountered in fields such as Engineering, Mathematics, and Physics to understand and model complex phenomena. We propose a novel method based on the dimension reduction philosophy called HyperCell. Its basic concept is to represent the function by means of dynamic orthogonal low (1D, 2D, or 3D) dimensional subspaces, called Cells. Firstly the user defines a N-dimensional region of interest, in which the data can be visualized. Then the user interactively creates cells by selecting up to three dimensions from the function domain. A cell can be visualized using a standard visualization algorithm such as isosurfacing or volume rendering. The analysis of the function is done by investigating several cells, which can be sampled simultaneously at different regions of interest in N-Space. The HyperCell method allows several useful operations to help the exploratory process such as navigation and rotation in N-Space, and brushing.
Volume Rendering Multivariate Data to Visualize Meteorological Simulations: A Case Study
Authors: Joe Kniss, Charles D. Hansen
Published at EuroVis, 2002

High resolution computational weather models are becoming increasing complex. However, the analysis of these models has not benefited from recent advancements in volume visualization. This case study applies the ideas and techniques from multi-dimensional transfer function based volume rendering to the multivariate weather simulations. The specific goal of identifying frontal zones is addressed. By combining temperature and humidity as a multivariate field, the frontal zones are more readily identified thereby assisting the meteorologists in their analysis tasks.
Vortex Tracking in Scale-Space
Authors: Dirk Bauer, Ronald Peikert
Published at EuroVis, 2002

Scale-space techniques have become popular in computer vision for their capability to access the multiscale information inherently contained in images. We show that the field of flow visualization can benefit from these techniques, too, yielding more coherent features and sorting out numerical artifacts as well as irrelevant large-scale features. We describe an implementation of scale-space computation using finite elements and show that performance is sufficient for computing a scale-space of time-dependent CFD data. Feature tracking, if available, allows to process the information provided by scale-space not just visually but also algorithmically. We present a technique for extending a class of feature extraction schemes by an additional dimension, resulting in an efficient solution of the tracking problem.
Automating CPM-GOMS
Authors: Bonnie E. John, Alonso H. Vera, Michael Matessa, Michael Freed, Roger W. Remington
Published at CHI, 2002

CPM-GOMS is a modeling method that combines the task decomposition of a GOMS analysis with a model of human resource usage at the level of cognitive, perceptual, and motor operations. CPM-GOMS models have made accurate predictions about skilled user behavior in routine tasks, but developing such models is tedious and error-prone. We describe a process for automatically generating CPM-GOMS models from a hierarchical task decomposition expressed in a cognitive modeling tool called Apex. Resource scheduling in Apex automates the difficult task of interleaving the cognitive, perceptual, and motor resources underlying common task operators (e.g. mouse move-and-click). Apex's UI automatically generates PERT charts, which allow modelers to visualize a model's complex parallel behavior. Because interleaving and visualization is now automated, it is feasible to construct arbitrarily long sequences of behavior. To demonstrate the process, we present a model of automated teller interactions in Apex and discuss implications for user modeling
Keeping things in context: a comparative evaluation of focus plus context screens, overviews, and zooming
Authors: Patrick Baudisch, Nathaniel Good, Victoria Bellotti, Pamela K. Schraedley
Published at CHI, 2002

Users working with documents that are too large and detailed to fit on the user's screen (e.g. chip designs) have the choice between zooming or applying appropriate visualization techniques. In this paper, we present a comparison of three such techniques. The first, focus plus context screens, are wall-size low-resolution displays with an embedded high-resolution display region. This technique is compared with overview plus detail and zooming/panning. We interviewed fourteen visual surveillance and design professionals from different areas (graphic design, chip design, air traffic control, etc.) in order to create a repre sentative sample of tasks to be used in two experimental comparison studies. In the first experiment, subjects using focus plus context screens to extract information from large static documents completed the two experimental tasks on average 21% and 36% faster than when they used the other interfaces. In the second experiment, focus plus context screens allowed subjects to reduce their error rate in a driving simulation to less than one third of the error rate of the competing overview plus detail setup
Polyarchy visualization: visualizing multiple intersecting hierarchies
Authors: George G. Robertson, Kim Cameron, Mary Czerwinski, Daniel C. Robbins
Published at CHI, 2002

We describe a new information structure composed of multiple intersecting hierarchies, which we call Polyarchies. Visualizing polyarchies enables use of novel views for discovery of relationships which are very difficult using existing hierarchy visualization tools. This paper will describe the visualization design and system architecture challenges as well as our current solutions. A Mid-Tier Cache architecture is used as a "polyarchy server" which supports a novel web-based polyarchy visualization technique, called Visual Pivot. A series of five user studies guided iterative design of Visual Pivot
4D space-time techniques: a medical imaging case study
Authors: Melanie Tory, Niklas Röber, Torsten Möller, Anna Celler, M. Stella Atkins
Published at Vis, 2001

We present the problem of visualizing time-varying medical data. Two medical imaging modalities are compared-MRI and dynamic SPECT. For each modality, we examine several derived scalar and vector quantities such as the change in intensity over time, the spatial gradient, and the change of the gradient over time. We compare several methods for presenting the data, including isosurfaces, direct volume rendering, and vector visualization using glyphs. These techniques may provide more information and context than methods currently used in practice; thus it is easier to discover temporal changes and abnormalities in a data set.
A case study on interactive exploration and guidance aids for visualizing historical data
Authors: Stanislav L. Stoev, Wolfgang Straßer
Published at Vis, 2001

In this paper, we address the problem of historical data visualization. We describe the data acquisition, preparation, and visualization. Since the data contain four dimensions, the standard 3D exploration techniques have to be extended or appropriately adapted in order to enable interactive exploration. We discuss in detail two interaction concepts: (1) navigation with one fixed dimension, and (2) quasi 4D navigation allowing to simultaneously explore the four-dimensional space. In addition, we also present a picture-in-picture display mode, enabling the user to interactively view the data, while "flying with" a particular event, tracking its motion in time and space. Finally, we present a technique for guided exploration and animation generation, allowing for a vivid gain of insight into the historical data.
A complete distance field representation
Authors: Jian Huang, Yan Li, Roger Crawfis, Shao-Chiung Lu, Shuh-Yuan Liou
Published at Vis, 2001

Distance fields are an important volume representation. A high quality distance field facilitates accurate surface characterization and gradient estimation. However, due to Nyquist's law, no existing volumetric methods based on the linear sampling theory can fully capture surface details, such as comers and edges, in 3D space. We propose a novel complete distance field representation (CDFR) that does not rely on Nyquist's sampling theory. To accomplish this, we construct a volume where each voxel has a complete description of all portions of surface that affect the local distance field. For any desired distance, we are able to extract a surface contour in true Euclidean distance, at any level of accuracy, from the same CDFR representation. Such point-based iso-distance contours have faithful per-point gradients and can be interactively visualized using splatting, providing per-point shaded image quality. We also demonstrate applying CDFR to a cutting edge design for manufacturing application involving high-complexity parts at unprecedented accuracy using only commonly available computational resources.
A memory insensitive technique for large model simplification
Authors: Peter Lindstrom 0001, Cláudio T. Silva
Published at Vis, 2001

The authors propose three simple, but significant improvements to the OoCS (Out-of-Core Simplification) algorithm of P. Lindstrom (2000) which increase the quality of approximations and extend the applicability of the algorithm to an even larger class of compute systems. The original OoCS algorithm has memory complexity that depends on the size of the output mesh, but no dependency on the size of the input mesh. That is, it can be used to simplify meshes of arbitrarily large size, but the complexity of the output mesh is limited by the amount of memory available. Our first contribution is a version of OoCS that removes the dependency of having enough memory to hold (even) the simplified mesh. With our new algorithm, the whole process is made essentially independent of the available memory on the host computer. Our new technique uses disk instead of main memory, but it is carefully designed to avoid costly random accesses. Our two other contributions improve the quality of the approximations generated by OoCS. We propose a scheme for preserving surface boundaries which does not use connectivity information, and a scheme for constraining the position of the "representative vertex" of a grid cell to an optimal position inside the cell.
A simple algorithm for surface denoising
Authors: Jianbo Peng, Vasily Strela, Denis Zorin
Published at Vis, 2001

We present a simple denoising technique for geometric data represented as a semiregular mesh, based on locally adaptive Wiener filtering. The degree of denoising is controlled by a single parameter (an estimate of the relative noise level) and the time required for denoising is independent of the magnitude of the estimate. The performance of the algorithm is sufficiently fast to allow interactive local denoising.
A tetrahedra-based stream surface algorithm
Authors: Gerik Scheuermann, Tom Bobach, Hans Hagen, Karim Mahrous, Bernd Hamann, Kenneth I. Joy, Wolfgang Kollmann
Published at Vis, 2001

This paper presents a new algorithm for the calculation of stream surfaces for tetrahedral grids. It propagates the surface through the tetrahedra, one at a time, calculating the intersections with the tetrahedral faces. The method allows us to incorporate topological information from the cells, e.g. critical points. The calculations are based on barycentric coordinates, since this simplifies the theory and the algorithm. The stream surfaces are ruled surfaces inside each cell, and their construction starts with line segments on the faces. Our method supports the analysis of velocity fields resulting from computational fluid dynamics (CFD) simulations.
A virtual environment for simulated rat dissection: a case study of visualization for astronaut training
Authors: Kevin Montgomery, Cynthia Bruyns, Simon Wildermuth
Published at Vis, 2001

Animal dissection for the scientific examination of organ subsystems is a delicate procedure. Performing this procedure under the complex environment of microgravity presents additional challenges because of the limited training opportunities available that can recreate the altered gravity environment. Traditional astronaut crew training often occurs several months in advance of experimentation, provides limited realism, and involves complicated logistics. We have developed an interactive virtual environment that can simulate several common tasks performed during animal dissection. In this paper, we describe the imaging modality used to reconstruct the rat, provide an overview of the simulation environment and briefly discuss some of the techniques used to manipulate the virtual rat.
Accelerated volume ray-casting using texture mapping
Authors: Rüdiger Westermann, Bernd Sevenich
Published at Vis, 2001

Acceleration techniques for volume ray-casting are primarily based on pre-computed data structures that allow one to efficiently traverse empty or homogeneous regions. In order to display volume data that successively undergoes color lookups, however, the data structures have to be re-built continuously. In this paper we propose a technique that circumvents this drawback using hardware accelerated texture mapping. In a first rendering pass we employ graphics hardware to interactively determine for each ray where the material is hit. In a second pass ray-casting is performed, but ray traversal starts right in front of the previously determined regions. The algorithm enables interactive classification and it considerably accelerates the view dependent display of selected materials and surfaces from volume data. In contrast to other techniques that are solely based on texture mapping our approach requires less memory and accurately performs the composition of material contributions along the ray.
An immersive virtual environment for DT-MRI volume visualization applications: a case study
Authors: Song Zhang 0004, Çagatay Demiralp, Daniel F. Keefe, M. DaSilva, David H. Laidlaw, Benjamin D. Greenberg, Peter J. Basser, Carlo Pierpaoli, E. A. Chiocca, Thomas S. Deisboeck
Published at Vis, 2001

We describe a virtual reality environment for visualizing tensor-valued volumetric datasets acquired with diffusion tensor magnetic resonance imaging (DT-MRI). We have prototyped a virtual environment that displays geometric representations of the volumetric second-order diffusion tensor data and are developing interaction and visualization techniques for two application areas: studying changes in white-matter structures after gamma-knife capsulotomy and pre-operative planning for brain tumor surgery. Our feedback shows that compared to desktop displays, our system helps the user better interpret the large and complex geometric models, and facilitates communication among a group of users.
Approximate shading for the re-illumination of synthetic images
Authors: Randy K. Scoggins, Raghu Machiraju, Robert J. Moorhead II
Published at Vis, 2001

Presents a method to estimate illumination dependent properties in image synthesis prior to rendering. A preprocessing step is described in which a linear image basis is developed and a lighting-independent formulation defined. A reflection function, similar to hemispherical reflectance, approximates normal Lambertian shading. Intensity errors resulting from this approximation are reduced by use of a polynomial gamma correction function and scaling to a normalized display range. This produces images that are similar to normal Lambertian shading without employing the maximum (max) function. For a single object view, images can then be expressed in a linear form so that lighting direction can be factored out. During normal rendering, image quantities for arbitrary light directions can be found without rendering. This method is demonstrated for estimating image intensity and level-of-detail error prior to rendering an object.