IVAPP 2010 Abstracts

Full Papers Short Papers
Full Papers
Paper Nr: 13
Title:

Effectiveness of visualisations for detection of errors in segmentation of blood vessels
Authors:

Boris van Schooten, Betsy van Dijk, Avan Suinesiaputra and Hans Reiber
Abstract: Vascular disease diagnosis often requires a precise segmentation of the vessel lumen. When 3D (Magnetic Resonance Angiography, MRA, or Computed Tomography Angiography, CTA) imaging is available, this can be done automatically, but occasional errors are inevitable. So, the segmentation has to be checked by clinicians. This requires appropriate visualisation techniques. A number of visualisation techniques exist, but there has been little in the way of user studies that compare the different alternatives. In this study we examine how users interact with several basic visualisations, when performing a visual search task, checking vascular segmentation correctness of segmented MRA data. These visualisations are: direct volume rendering (DVR), isosurface rendering, and curved planar reformatting (CPR). Additionally, we examine if visual highlighting of potential errors can help the user find errors, so a fourth visualisation we examine is DVR with visual highlighting. Our main findings are that CPR performs fastest but has higher error rate, and there are no significant differences between the other three visualisations. We did find that visual highlighting actually has slower performance in early trials, suggesting that users learned to ignore them.
Download
Paper Nr: 16
Title:

The Song Picture: On Musical Information Visualization for Audio and Video Editing
Authors:

Marcelo Cicconet and Paulo C. Carvalho
Abstract: Most audio and video editors employ a representation of music pieces based on the Pulse Code Modulation waveform, from which not much information, besides the energy envelope, can be visually captured. In the present work we discuss the importance of presenting to the user some hints about the melodic content of the audio to improve the visual segmentation of a music piece, thereby speeding up editing tasks. Such a representation, although powerful in the mentioned sense, is of simple computation, a desirable property because loading an audio or video should be done very fast in an interactive environment.
Download
Paper Nr: 17
Title:

Understanding changes in heritage architecture - Can we provide tools & methods for visual reasoning?
Authors:

Jean-Yves Blaise and Iwona DUDEK
Abstract: When studying heritage architecture, and trying to represent and understand the development of artefacts, one should not only examine key moments in their evolution, but describe the whole process of their transformation - thereby correlating contextual causes and architectural consequences. In this contribution, we introduce a methodological framework of description of architectural changes, the corresponding visual tools, and finally present elements of evaluation. The results we report show the description framework favours information discovery: cross-examination of cases, analysis of causal relations, patterns of change, etc.
Download
Paper Nr: 18
Title:

Multiscale Visualization of Relational Databases Using Layered Zoom Trees and Partial Data Cubes
Authors:

Baoyuan Wang, Gang Chen, Jiajun Bu and Yizhou Yu
Abstract: The analysis and exploration necessary to gain deep understanding of large databases demand an intuitive and informative human-computer interface. In this paper, we present a visualization system with a client-server architecture for multiscale visualization of relational databases. The visual interface on the client supports web-based remote access. We use zoom trees to represent the history of a zooming process that reveals multiscale details. Zoom trees support arbitrary branching and backtracking. Only one path in a zoom tree is visualized at any time to save screen space. Zoom trees are seamlessly integrated with a table-based overview using "hyperlinks" embedded in the table. To support fast query processing on the server, we further develop efficient algorithms for GPU-based online data cubing and CPU-based data clustering. Also, a user study was conducted to evaluate the effectiveness of our design.
Download
Paper Nr: 27
Title:

On-Demand High-Performance Visualization of Spatial Data on High-Resolution Tiled Display Walls
Authors:

Tor-Magne S. Hagen, Daniel Stødle and Otto Anshus
Abstract: Visualization of large data sets on high-resolution display walls is useful and can lead to new discoveries that would not have been noticeable on regular displays. However, exploring such data sets with interactive performance is challenging. This paper presents live data sets, a scalable architecture for visualization of large data sets on display walls. The architecture separates visualization systems from compute systems using a live data set containing data customized for the particular visualization domain. Experiments conducted show that the main bottleneck is the compute resources producing data for the visualization side. When all data is cached in the live data set, the main bottleneck (decoding images to create OpenGL textures and constructing geometry from raster data) is on the visualization side. On a 22 megapixel, 28 node display wall, the visualization system can decode 414.2 megapixels of images (19 frames) per second. However, the decoding is multi-threaded, and increased performance is expected using multi-core computers.
Download
Short Papers
Paper Nr: 7
Title:

Encyclopedia Walkabouts with VisNomad: A New Visualization Tool Designed as an Aid for Textual Exploration
Authors:

Dominique Thiebaut and Larry Owens
Abstract: We present an original visualizer that allows users to travel through the network of pages of an early encyclopedia of computer science. The purpose of this tool is to better understand the relationship between concepts of computer science at an early stage in the development of the field. The visualizer is written in Java, interfaces to a database server, and sports two different graphical representations, a tree and a graph that are logically connected. We present our design goals, our choices of implementations and the challenges encountered.
Download
Paper Nr: 10
Title:

Visualization of Uncertain Contour Trees
Authors:

Martin Kraus and Martin Kraus
Abstract: Contour trees can represent the topology of large volume data sets in a relatively compact, discrete data structure. However, the resulting trees often contain many thousands of nodes; thus, many graph drawing techniques fail to produce satisfactory results. Therefore, several visualization methods were proposed recently for the visualization of contour trees. Unfortunately, none of these techniques is able to handle uncertain contour trees although any uncertainty of the volume data inevitably results in partially uncertain contour trees. In this work, we visualize uncertain contour trees by combining the contour trees of two morphologically filtered versions of a volume data set, which represent the range of uncertainty. These two contour trees are combined and visualized within a single image such that a range of potential contour trees is represented by the resulting visualization. Thus, potentially erroneous topological structures are visually distinguished from more certain structures. Moreover, topological structures can be revealed that are otherwise obscured by data errors. We present and discuss results obtained with a prototypical implementation using well-known volume data sets.
Download
Paper Nr: 28
Title:

3D VISUALISATION AND VIRTUAL REALITY FOR VISUAL DATA MINING : A SURVEY
Authors:

Zohra Ben Said, Fabrice Guillet and Paul Richard
Abstract: Visual Data Mining (VDM) aims at an easier interpretation of data mining algorithm results through the use of visualization techniques. During the last decade, many techniques of information visualization have been proposed, enabling visualization of multidimensional data. In previous work, researchers have attempted to classify VDM techniques ((Chi, 2000), (Herman et al., 2000)). However, these taxonomies do not take into account some innovative techniques based on 3D visualization and virtual environments (VEs). In this paper, we propose an exhaustive survey of recent techniques for VDM. These are detailed, classified and compared according to the following criteria : graphical encoding, interaction techniques and applications. Moreover, they are presented in tables together with graphic illustrations.
Download
Paper Nr: 30
Title:

DATA VISUALIZATION FOR ANALYZING SIMULATED ROBOTIC SOCCER GAMES
Authors:

Brígida Faria, Beatriz S. Santos, Nuno Lau and Luís Paulo Reis
Abstract: RoboCup is an international cooperative research project aimed at promoting research in Artificial Intelligence and Robotics. It includes a simulation league where two teams of 11 players compete in a robotic soccer game very similar to real soccer. Teams exhibit very complex strategies in these games that are very difficult to analyze by conventional observation methods. This paper presents an approach to the visualization of simulated robotic soccer games using the RapidMiner software package. Various visualizations were developed using Andrew´s Curves, Survey Plots, several types of Parallel Coordinate visualizations and Radial Coordinate Visualizations. These visualizations enabled to take some interesting conclusions about the differences between games of FC Portugal robotic soccer team using different formations and against distinct opponents.
Download
Paper Nr: 15
Title:

FOLDER3D: A Graphical File Management System Supporting Visualisation of File Relationships
Authors:

Bill Rogers, Saturnino Luz, Masood Masoodian, Bill Rogers and Simon De Schutter
Abstract: The desktop metaphor with its hierarchical structure of folders is the basis of almost all graphical file management systems. Despite this popularity, these systems suffer from several problems, including the restrictiveness of the single inheritance structure of hierarchical file management. Although various alternative systems have been proposed, none of these have gained popularity. We argue that the reason for this failure is that these systems have generally proposed complete alternatives to the hierarchical system, thus ignoring many of its positive aspects. In this paper we describe a 3D graphical file management which complements conventional 2D hierarchical folder structures by allowing visualisation of alternative file relationships.
Download
Paper Nr: 20
Title:

Generating a Visual Overview of Large Diachronic Document Collections based on the Detection of Topic Change
Authors:

Florian Holz, Sven Teresniak, Gerhard Heyer and Gerik Scheuermann
Abstract: Large digital diachronic document collections are a central source of information in science, business, and for the general public. One challenge for the efficient visualization of these collections is the automatic calculation and visualization of the main topics. These topics can then serve as the basis for an overview of the content and any subsequent interactive visual analysis. We introduce the new language processing concept of volatility of terms measured as the change of the context of terms. We demonstrate that volatility can serve as an excellent basis for the visual overview of large collections using two different examples
Download
Paper Nr: 22
Title:

VISUALIZATION OF DOCUMENT CLUSTERS An interactive visual tool to browse textual documents
Authors:

Faryel Allouti, Mohamed Nadif and Benoît Otjacques
Abstract: Handling collections of text documents has become a daily task for many professionals whatever their economic sector or position in the organization. In many cases, little metadata is added to the documents, which makes it difficult to automatically derive a semantic structure within the collection. This paper describes a new tool that combines the clustering and the visualization paradigms to help a user identify similar documents in an unstructured collection. Several clustering algorithms can be used to identify clusters of documents that are subsequently displayed on a plane. In this work, we use the Classification EM algorithm. The originality of our approach is to allow the user to refine the clustering process interactively by means of a visual analysis of the results of the intermediate steps. In addition, the tool also shows some enriched views of the content of documents and allows the user to include a semantic analysis based on personal knowledge to the computer-based clustering process.
Download