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Scented widgets: Improving navigation cues with embedded visualizations

IEEE TRANSACTIONS ON visualization AND COMPUTER GRAPHICS 2007年第6期13卷 1129-1136页

作者： Willett, Wesley Heer, Jeffrey Agrawala, Maneesh Univ Calif Berkeley Div Comp Sci Berkeley CA 94720 USA

This paper presents scented widgets, graphical user interface controls enhanced with embedded visualizations that facilitate navigation in information spaces. We describe design guidelines for adding visual cues to common user interface widgets such as radio buttons, sliders, and combo boxes and contribute a general software framework for applying scented widgets within applications with minimal modifications to existing source code. We provide a number of example applications and describe a controlled experiment which finds that users exploring unfamiliar data make up to twice as many unique discoveries using widgets imbued with social navigation data. However, these differences equalize as familiarity with the data increases.

关键词： information visualization user interface toolkits information foraging social navigation social data analysis

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Sequential document visualization

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IEEE TRANSACTIONS ON visualization AND COMPUTER GRAPHICS 2007年第6期13卷 1208-1215页

作者： Mao, Yi Dillon, Joshua V. Lebanon, Guy Purdue Univ Sch Elect & Comp Engn W Lafayette IN 47907 USA Purdue Univ Sch Elect & Comp Engn Dept Stat W Lafayette IN 47907 USA

Documents and other categorical valued time series are often characterized by the frequencies of short range sequential patterns such as n-grams. This representation converts sequential data of varying lengths to high dimensional histogram vectors which are easily modeled by standard statistical models. Unfortunately, the histograrn representation ignores most of the medium and long range sequential dependencies making it unsuitable for visualizing sequential data. We present a novel framework for sequential visualization of discrete categorical time series based on the idea of local statistical modeling. The framework embeds categorical time series as smooth curves in the multinomial simplex summarizing the progression of sequential trends. We discuss several visualization techniques based on the above framework and demonstrate their usefulness for document visualization.

关键词： document visualization multi-resolution analysis local fitting

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Efficient computation and visualization of coherent structures in fluid flow applications

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IEEE TRANSACTIONS ON visualization AND COMPUTER GRAPHICS 2007年第6期13卷 1464-1471页

作者： Garth, Christoph Gerhardt, Florian Tricoche, Xavier Hagen, Hans Univ Kaiserslautern D-67663 Kaiserslautern Germany Univ Calif Davis Inst Data Anal & Visualizat Davis CA 95616 USA Univ Utah SCI Inst Salt Lake City UT 84112 USA Purdue Univ W Lafayette IN 47907 USA

The recently introduced notion of Finite-Time Lyapunov Exponent to characterize Coherent Lagrangian Structures provides a powerful framework for the visualization and analysis of complex technical flows. Its definition is simple and intuitive, and it has a deep theoretical foundation. While the application of this approach seems straightforward in theory, the associated computational cost is essentially prohibitive. Due to the Lagrangian nature of this technique, a huge number of particle paths must be computed to fill the space-time flow domain. In this paper, we propose a novel scheme for the adaptive computation of FTLE fields in two and three dimensions that significantly reduces the number of required particle paths. Furthermore, for three-dimensional flows, we show on several examples that meaningful results can be obtained by restricting the analysis to a well-chosen plane intersecting the flow domain. Finally, we examine some of the visualization aspects of FTLE-based methods and introduce several new variations that help in the analysis of specific aspects of a flow.

关键词： flow visualization feature detection 3D vector field visualization

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Geographically weighted visualization: Interactive graphics for scale-varying exploratory analysis

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IEEE TRANSACTIONS ON visualization AND COMPUTER GRAPHICS 2007年第6期13卷 1161-1168页

作者： Dykes, Jason Brunsdon, Chris City Univ London Dept Informat Sci London EC1V 0HB England Univ Leicester Dept Geog Leicester LE1 7RH Leics England

We introduce a series of geographically weighted (GW) interactive graphics, or geowigs, and use them to explore spatial relationships at a range of scales. We visually encode information about geographic and statistical proximity and variation in novel ways through gw-choropleth maps, multivariate gw-boxplots, gw-shading and scalograms. The new graphic types reveal information about GW statistics at several scales concurrently. We impernent these views in prototype software containing dynamic links and GW interactions that encourage exploration and refine them to consider directional geographies. An informal evaluation uses interactive GW techniques to consider Guerry's clataset of 'moral statistics', casting doubt on correlations originally proposed through visual analysis, revealing new local anomalies and suggesting multivariate geographic relationships. Few attempts at visually synthesising geography with multivariate statistical values at multiple scales have been reported. The geowigs proposed here provide informative representations of multivariate local variation, particularly when combined with interactions that coordinate views and result in gw-shading. We argue that they are widely applicable to area and point-based geographic data and provide a set of methods to support visual analysis using GW statistics through which the effects of geography can be explored at multiple scales.

关键词： geographical weighting exploratory data analysis scale multivariate directional interaction coordinated views

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Interactive visual exploration of a large spatio-temporal dataset: Reflections on a geovisualization mashup

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IEEE TRANSACTIONS ON visualization AND COMPUTER GRAPHICS 2007年第6期13卷 1176-1183页

作者： Wood, Jo Dykes, Jason Slingsby, Aidan Clarke, Keith City Univ London Dept Informat Sci London England Univ Calif Santa Barbara Dept Geog Santa Barbara CA 93106 USA

Exploratory visual analysis is useful for the preliminary investigation of large structured, multifaceted spatio-temporal datasets. This process requires the selection and aggregation of records by time, space and attribute, the ability to transform data and the flexibility to apply appropriate visual encodings and interactions. We propose an approach inspired by geographical 'mashups' in which freely-available functionality and data are loosely but flexibly combined using de facto exchange standards. Our case study combines MySQL, PHP and the LandSerf GIS to allow Google Earth to be used for visual synthesis and interaction with encodings described in KML. This approach is applied to the exploration of a log of 1.42 million requests made of a mobile directory service. Novel combinations of interaction and visual encoding are developed including spatial 'tag clouds', 'tag maps', 'data dials' and multi-scale density surfaces. Four aspects of the approach are informally evaluated: the visual encodings employed, their success in the visual exploration of the clataset, the specific tools used and the 'rnashup' approach. Preliminary findings will be beneficial to others considering using mashups for visualization. The specific techniques developed may be more widely applied to offer insights into the structure of multifarious spatio-temporal data of the type explored here.

关键词： large dataset visualization text and document visualization multiresolution visualization geographic visualization applications of infovis

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Hotmap: Looking at geographic attention

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IEEE TRANSACTIONS ON visualization AND COMPUTER GRAPHICS 2007年第6期13卷 1184-1191页

作者： Fisher, Danyel Microsoft Res VIBE Lab Redmond WA 98052 USA

Understanding how people use online maps allows data acquisition teams to concentrate their efforts on the portions of the map that are most seen by users. Online maps represent vast databases, and so it is insufficient to simply look at a list of the most-accessed URLs. Hotmap takes advantage of the design of a mapping System's imagery pyramid to superpose a heatmap of the log files over the original maps. Users' behavior within the system can be observed and interpreted. This paper discusses the imagery acquisition task that motivated Hotmap, and presents several examples of information that Hotmap makes visible. We discuss the design choices behind Hotmap, including logarithmic color schemes;low-saturation background images;and tuning images to explore both infrequently-viewed and frequently-viewed spaces.

关键词： geographical visualization GIS heatmap server log analysis online mapping systems social navigation

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Segmentation of three-dimensional retinal image data

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IEEE TRANSACTIONS ON visualization AND COMPUTER GRAPHICS 2007年第6期13卷 1719-1726页

作者： Fuller, Alfred R. Zawadzki, Robert J. Choi, Stacey Wiley, David F. Werner, John S. Hamann, Bernd Univ Calif Davis Inst Data Anal & Visualizat Davis CA 95616 USA Univ Calif Davis Dept Comp Sci Davis CA 95616 USA Univ Calif Davis Dept Ophthalmol Vis Sci & Adv Retinal Imaging Lab Davis CA 95616 USA

We have combined methods from volume visualization and data analysis to support better diagnosis and treatment of human retinal diseases. Many diseases can be identified by abnormalities in the thicknesses of various retinal layers captured using optical coherence tomography (OCT). We used a support vector machine (SVM) to perform semi-automatic segmentation of retinal layers for subsequent analysis including a comparison of layer thicknesses to known healthy parameters. We have extended and generalized an older SVM approach to support better performance in a clinical setting through performance enhancements and graceful handling of inherent noise in OCT data by considering statistical characteristics at multiple levels of resolution. The addition of the multi-resolution hierarchy extends the SVM to have "global awareness." A feature, such as a retinal layer, can therefore be modeled within the SVM as a combination of statistical characteristics across all levels;thus capturing high- and low-frequency information. We have compared our semi-automatically generated segmentations to manually segmented layers for verification purposes. Our main goals were to provide a tool that could (i) be used in a clinical setting;(ii) operate on noisy OCT data;and (iii) isolate individual or multiple retinal layers in both healthy and disease cases that contain structural deformities.

关键词： support vector machine segmentation image analysis retinal optical coherence tomography volume visualization image processing

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Visual verification and analysis of ciluster detection for molecular dynamics

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IEEE TRANSACTIONS ON visualization AND COMPUTER GRAPHICS 2007年第6期13卷 1624-1631页

作者： Grottel, S. Reina, G. Vrabec, J. Ertl, T. Univ Stuttgart Inst Visualizat & Interact Syst D-7000 Stuttgart Germany Univ Stuttgart Inst Thermodynam & Thermal Proc Engn D-7000 Stuttgart Germany

A current research topic in molecular thermodynamics is the condensation of vapor to liquid and the investigation of this process at the molecular level. Condensation is found in many physical phenomena, e.g. the formation of atmospheric clouds or the processes inside steam turbines, where a detailed knowledge of the dynamics of condensation processes will help to optimize energy efficiency and avoid problems with droplets of macroscopic size. The key properties of these processes are the nucleation rate and the critical cluster size. For the calculation of these properties it is essential to make use of a meaningful definition of molecular clusters, which currently is a not completely resolved issue. In this paper a framework capable of interactively visualizing molecular datasets of such nucleation simulations is presented, with an emphasis on the detected molecular clusters. To check the quality of the results of the cluster detection, our framework introduces the concept of flow groups to highlight potential cluster evolution over time which is not detected by the employed algorithm. To confirm the findings of the visual analysis, we coupled the rendering view with a schematic view of the clusters' evolution. This allows to rapidly assess the quality of the molecular cluster detection algorithm and to identify locations in the simulation data in space as well as in time where the cluster detection fails. Thus, thermodynamics researchers can eliminate weaknesses in their cluster detection algorithms. Several examples for the effective and efficient usage of our tool are presented.

关键词： cluster detection analysis molecular dynamics visualization time-dependent scattered data glyph visualization out-of-core techniques evolution graph view

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Moment invariants for the analysis of 2D flow fields

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IEEE TRANSACTIONS ON visualization AND COMPUTER GRAPHICS 2007年第6期13卷 1743-1750页

作者： Schlemmer, Michael Heringer, Manuel Morr, Florian Hotz, Ingrid Bertram, Martin-Hering Garth, Christoph Kollmann, Wolfgang Hamann, Bernd Hagen, Hans Univ Kaiserslautern D-67663 Kaiserslautern Germany Fraunhofer Inst Techno & Wirtsxhaftsmathemat ITWM Kaiserslautern Germany FU Berlin Konrad Zuse Zentrum Informat Tech Berlin ZIB Berlin Germany Univ Calif Davis Inst Data Anal & Visualizat Davis CA 95616 USA Univ Calif Davis Dept Mech & Aeronaut Engn Davis CA 95616 USA Univ Calif Davis Dept Comp Sci Davis CA 95616 USA

We present a novel approach for analyzing two-dimensional (2D) flow field data based on the idea of invariant moments. Moment invariants have traditionally been used in computer vision applications, and we have adapted them for the purpose of interactive exploration of flow field data. The new class of moment invariants we have developed allows us to extract and visualize 2D flow patterns, invariant under translation, scaling, and rotation. With our approach one can study arbitrary flow patterns by searching a given 2D flow data set for any type of pattern as specified by a user. Further, our approach supports the computation of moments at multiple scales, facilitating fast pattern extraction and recognition. This can be done for critical point classification, but also for patterns with greater complexity. This multi-scale moment representation is also valuable for the comparative visualization of flow field data. The specific novel contributions of the work presented are the mathematical derivation of the new class of moment invariants, their analysis regarding critical point features, the efficient computation of a novel feature space representation, and based upon this the development of a fast pattern recognition algorithm for complex flow structures.

关键词： flow visualization feature detection pattern extraction pattern recognition image processing

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Listener-based analysis of surface importance for acoustic metrics

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IEEE TRANSACTIONS ON visualization AND COMPUTER GRAPHICS 2007年第6期13卷 1680-1687页

作者： Michel, Frank Deines, Eduard Hering-Bertram, Martin Gairth, Christoph Hagen, Hans Univ Kaiserslautern D-67663 Kaiserslautern Germany Univ Calif Davis Inst Data Anal & Visualizat Davis CA 95616 USA

Acoustic quality in room acoustics is measured by well defined quantities, like definition, which can be derived from simulated impulse response filters or measured values. These take into account the intensity and phase shift of multiple reflections due to a wave front emanating from a sound source. Definition (D-50) and clarity (C-50) for example correspond to the fraction of the energy received in total to the energy received in the first 50 ms at a certain listener position. Unfortunately, the impulse response measured at a single point does not provide any information about the direction of reflections, and about the reflection surfaces which contribute to this measure. For the visualization of room acoustics, however, this information is very useful since it allows to discover regions with high contribution and provides insight into the influence of all reflecting surfaces to the quality measure. We use the phonon tracing method to calculate the contribution of the reflection surfaces to the impulse response for different listener positions. This data is used to compute importance values for the geometry taking a certain acoustic metric into account. To get a visual insight into the directional aspect, we map the importance to the reflecting surfaces of the geometry. This visualization indicates which parts of the surfaces need to be changed to enhance the chosen acoustic quality measure. We apply our method to the acoustic improvement of a lecture hall by means of enhancing the overall speech comprehensibility (clarity) and evaluate the results using glyphs to visualize the clarity (C-50) values at listener positions throughout the room.

关键词： sound analytics applications of visualization room acoustics phonon tracing acoustic metric

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