Conference stringclasses 6 values | Year int64 1.99k 2.03k | Title stringlengths 8 187 | DOI stringlengths 16 32 | Abstract stringlengths 128 7.15k ⌀ | Accessible bool 2 classes | Early bool 2 classes | AuthorNames-Deduped listlengths 1 24 | Award listlengths 0 2 | Resources listlengths 0 5 | ResourceLinks listlengths 0 10 |
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VAST | 2,010 | Multidimensional data dissection using attribute relationship graphs | 10.1109/VAST.2010.5652520 | Visual exploration and analysis is a process of discovering and dissecting the abundant and complex attribute relationships that pervade multidimensional data. Recent research has identified and characterized patterns of multiple coordinated views, such as cross-filtered views, in which rapid sequences of simple interactions can be used to express queries on subsets of attribute values. In visualizations designed around these patterns, for the most part, distinct views serve to visually isolate each attribute from the others. Although the brush-and-click simplicity of visual isolation facilitates discovery of many-to-many relationships between attributes, dissecting these relationships into more fine-grained one-to-many relationships is interactively tedious and, worse, visually fragmented over prolonged sequences of queries. This paper describes: (1) a method for interactively dissecting multidimensional data by iteratively slicing and manipulating a multigraph representation of data values and value co-occurrences; and (2) design strategies for extending the construction of coordinated multiple view interfaces for dissection as well as discovery of attribute relationships in multidimensional data sets. Using examples from different domains, we describe how attribute relationship graphs can be combined with cross-filtered views, modularized for reuse across designs, and integrated into broader visual analysis tools. The exploratory and analytic utility of these examples suggests that an attribute relationship graph would be a useful addition to a wide variety of visual analysis tools. | false | false | [
"Chris E. Weaver"
] | [] | [] | [] |
VAST | 2,010 | NetClinic: Interactive visualization to enhance automated fault diagnosis in enterprise networks | 10.1109/VAST.2010.5652910 | Diagnosing faults in an operational computer network is a frustrating, time-consuming exercise. Despite advances, automatic diagnostic tools are far from perfect: they occasionally miss the true culprit and are mostly only good at narrowing down the search to a few potential culprits. This uncertainty and the inability to extract useful sense from tool output renders most tools not usable to administrators. To bridge this gap, we present NetClinic, a visual analytics system that couples interactive visualization with an automated diagnostic tool for enterprise networks. It enables administrators to verify the output of the automatic analysis at different levels of detail and to move seamlessly across levels while retaining appropriate context. A qualitative user study shows that NetClinic users can accurately identify the culprit, even when it is not present in the suggestions made by the automated component. We also find that supporting a variety of sensemaking strategies is a key to the success of systems that enhance automated diagnosis. | false | false | [
"Zhicheng Liu",
"Bongshin Lee",
"Srikanth Kandula",
"Ratul Mahajan"
] | [] | [] | [] |
VAST | 2,010 | Poster: Dynamic time transformation for interpreting clusters of trajectories with space-time cube | 10.1109/VAST.2010.5653580 | We propose a set of techniques that support visual interpretation of trajectory clusters by transforming absolute time references into relative positions within temporal cycles or with respect to the starting and/or ending times of the trajectories. We demonstrate the work of the approach on a real data set about individual movement over one year. | false | false | [
"Gennady L. Andrienko",
"Natalia V. Andrienko"
] | [] | [] | [] |
VAST | 2,010 | Poster: Translating cross-filtered queries into questions | 10.1109/VAST.2010.5650251 | Complex combinations of coordinated multiple views are increasingly used to design tools for highly interactive visual exploration and analysis of multidimensional data. While complex coordination patterns provide substantial utility through expressive querying, they also exhibit usability problems for users when learning required interaction sequences, recalling past queries, and interpreting visual states. As visual analysis tools grow more sophisticated, there is a growing need to make them more understandable as well. Our long-term goal is to exploit natural language familiarity and literacy to directly facilitate individual and collaborative use of visual analysis tools. In this poster, we present work in progress on an automatically generated query-to-question user interface to translate interactive states during visual analysis into an accompanying visual log of formatted text. Our effort currently focuses on a symmetric and thus relatively simple coordination pattern: cross-filtered views. We describe our current thinking about query-to-question translation in a typical cross-filtered visualization of movies, people, and genres in the Internet Movie Database. | false | false | [
"Maryam Nafari",
"Chris E. Weaver"
] | [] | [] | [] |
VAST | 2,010 | ProDV - A case study in delivering visual analytics | 10.1109/VAST.2010.5650219 | We present a custom visual analytics system developed in conjunction with the test and evaluation community of the US Army. We designed and implemented a visual programming environment for configuring a variety of interactive visual analysis capabilities. Our abstraction of the visualization process is based on insights gained from interviews conducted with expert users. We show that this model allowed analysts to implement multiple visual analysis capabilities for network performance, anomalous sensor activity, and engagement results. Long-term interaction with expert users led to development of several custom visual analysis techniques. We have conducted training sessions with expert users, and are working to evaluate the success of our work based on performance metrics captured in a semi-automated fashion during these training sessions. We have also integrated collaborative analysis features such as annotations and shared content. | false | false | [
"Derek Overby",
"John Keyser",
"Jim Wall"
] | [] | [] | [] |
VAST | 2,010 | Real-time aggregation of Wikipedia data for visual analytics | 10.1109/VAST.2010.5652896 | Wikipedia has been built to gather encyclopedic knowledge using a collaborative social process that has proved its effectiveness. However, the workload required for raising the quality and increasing the coverage of Wikipedia is exhausting the community. Based on several participatory design sessions with active Wikipedia contributors (a.k.a. Wikipedians), we have collected a set of measures related to Wikipedia activity that, if available and visualized effectively, could spare a lot of monitoring time to these Wikipedians, allowing them to focus on quality and coverage of Wikipedia instead of spending their time navigating heavily to track vandals and copyright infringements. However, most of these measures cannot be computed on the fly using the available Wikipedia API. Therefore, we have designed an open architecture called WikiReactive to compute incrementally and maintain several aggregated measures on the French Wikipedia. This aggregated data is available as a Web Service and can be used to overlay information on Wikipedia articles through Wikipedia Skins or for new services for Wikipedians or people studying Wikipedia. This article describes the architecture, its performance and some of its uses. | false | false | [
"Nadia Boukhelifa",
"Fanny Chevalier",
"Jean-Daniel Fekete"
] | [] | [] | [] |
VAST | 2,010 | Towards the Personal Equation of Interaction: The impact of personality factors on visual analytics interface interaction | 10.1109/VAST.2010.5653587 | These current studies explored the impact of individual differences in personality factors on interface interaction and learning performance behaviors in both an interactive visualization and a menu-driven web table in two studies. Participants were administered 3 psychometric measures designed to assess Locus of Control, Extraversion, and Neuroticism. Participants were then asked to complete multiple procedural learning tasks in each interface. Results demonstrated that all three measures predicted completion times. Additionally, results analyses demonstrated personality factors also predicted the number of insights participants reported while completing the tasks in each interface. We discuss how these findings advance our ongoing research in the Personal Equation of Interaction. | false | false | [
"Tera Marie Green",
"Brian D. Fisher"
] | [] | [] | [] |
VAST | 2,010 | Two-stage framework for a topology-based projection and visualization of classified document collections | 10.1109/VAST.2010.5652940 | During the last decades, electronic textual information has become the world's largest and most important information source. Daily newspapers, books, scientific and governmental publications, blogs and private messages have grown into a wellspring of endless information and knowledge. Since neither existing nor new information can be read in its entirety, we rely increasingly on computers to extract and visualize meaningful or interesting topics and documents from this huge information reservoir. In this paper, we extend, improve and combine existing individual approaches into an overall framework that supports topologi-cal analysis of high dimensional document point clouds given by the well-known tf-idf document-term weighting method. We show that traditional distance-based approaches fail in very high dimensional spaces, and we describe an improved two-stage method for topology-based projections from the original high dimensional information space to both two dimensional (2-D) and three dimensional (3-D) visualizations. To demonstrate the accuracy and usability of this framework, we compare it to methods introduced recently and apply it to complex document and patent collections. | false | false | [
"Patrick Oesterling",
"Gerik Scheuermann",
"Sven Teresniak",
"Gerhard Heyer",
"Steffen Koch 0001",
"Thomas Ertl",
"Gunther H. Weber"
] | [] | [] | [] |
VAST | 2,010 | Understanding text corpora with multiple facets | 10.1109/VAST.2010.5652931 | Text visualization becomes an increasingly more important research topic as the need to understand massive-scale textual information is proven to be imperative for many people and businesses. However, it is still very challenging to design effective visual metaphors to represent large corpora of text due to the unstructured and high-dimensional nature of text. In this paper, we propose a data model that can be used to represent most of the text corpora. Such a data model contains four basic types of facets: time, category, content (unstructured), and structured facet. To understand the corpus with such a data model, we develop a hybrid visualization by combining the trend graph with tag-clouds. We encode the four types of data facets with four separate visual dimensions. To help people discover evolutionary and correlation patterns, we also develop several visual interaction methods that allow people to interactively analyze text by one or more facets. Finally, we present two case studies to demonstrate the effectiveness of our solution in support of multi-faceted visual analysis of text corpora. | false | false | [
"Lei Shi 0002",
"Furu Wei",
"Shixia Liu",
"Li Tan",
"Xiaoxiao Lian",
"Michelle X. Zhou"
] | [] | [] | [] |
VAST | 2,010 | Visual analysis of frequent patterns in large time series | 10.1109/VAST.2010.5650766 | The detection of previously unknown, frequently occurring patterns in time series, often called motifs, has been recognized as an important task. To find these motifs, we use an advanced temporal data mining algorithm. Since our algorithm usually finds hundreds of motifs, we need to analyze and access the discovered motifs. For this purpose, we introduce three novel visual analytics methods: (1) motif layout, using colored rectangles for visualizing the occurrences and hierarchical relationships of motifs in a multivariate time series, (2) motif distortion, for enlarging or shrinking motifs as appropriate for easy analysis and (3) motif merging, to combine a number of identical adjacent motif instances without cluttering the display. We have applied and evaluated our methods using two real-world data sets: data center cooling and oil well production. | false | false | [
"Ming C. Hao",
"Manish Marwah",
"Halldór Janetzko",
"Daniel A. Keim",
"Umeshwar Dayal",
"Ratnesh K. Sharma",
"Debprakash Patnaik",
"Naren Ramakrishnan"
] | [] | [] | [] |
VAST | 2,010 | Visual exploration of classification models for risk assessment | 10.1109/VAST.2010.5652398 | In risk assessment applications well informed decisions are made based on huge amounts of multi-dimensional data. In many domains not only the risk of a wrong decision, but in particular the trade-off between the costs of possible decisions are of utmost importance. In this paper we describe a framework tightly integrating interactive visual exploration with machine learning to support the decision making process. The proposed approach uses a series of interactive 2D visualizations of numeric and ordinal data combined with visualization of classification models. These series of visual elements are further linked to the classifier's performance visualized using an interactive performance curve. An interactive decision point on the performance curve allows the decision maker to steer the classification model and instantly identify the critical, cost changing data elements, in the various linked visualizations. The critical data elements are represented as images in order to trigger associations related to the knowledge of the expert. In this context the data visualization and classification results are not only linked together, but are also linked back to the classification model. Such a visual analytics framework allows the user to interactively explore the costs of his decisions for different settings of the model and accordingly use the most suitable classification model and make more informed and reliable decisions. A case study on data from the Forensic Psychiatry domain reveals the usefulness of the suggested approach. | false | false | [
"Gosia Migut",
"Marcel Worring"
] | [] | [] | [] |
VAST | 2,010 | Visual market sector analysis for financial time series data | 10.1109/VAST.2010.5652530 | The massive amount of financial time series data that originates from the stock market generates large amounts of complex data of high interest. However, adequate solutions that can effectively handle the information in order to gain insight and to understand the market mechanisms are rare. In this paper, we present two techniques and applications that enable the user to interactively analyze large amounts of time series data in real-time in order to get insight into the development of assets, market sectors, countries, and the financial market as a whole. The first technique allows users to quickly analyze combinations of single assets, market sectors as well as countries, compare them to each other, and to visually discover the periods of time where market sectors and countries get into turbulence. The second application clusters a selection of large amounts of financial time series data according to their similarity, and analyzes the distribution of the assets among market sectors. This allows users to identify the characteristic graphs which are representative for the development of a particular market sector, and also to identify the assets which behave considerably differently compared to other assets in the same sector. Both applications allow the user to perform investigative exploration techniques and interactive visual analysis in real-time. | false | false | [
"Hartmut Ziegler",
"Marco Jenny",
"Tino Gruse",
"Daniel A. Keim"
] | [] | [] | [] |
VAST | 2,010 | Visual readability analysis: How to make your writings easier to read | 10.1109/VAST.2010.5652926 | We present a tool that is specifically designed to support a writer in revising a draft-version of a document. In addition to showing which paragraphs and sentences are difficult to read and understand, we assist the reader in understanding why this is the case. This requires features that are expressive predictors of readability, and are also semantically understandable. In the first part of the paper, we therefore discuss a semi-automatic feature selection approach that is used to choose appropriate measures from a collection of 141 candidate readability features. In the second part, we present the visual analysis tool VisRA, which allows the user to analyze the feature values across the text and within single sentences. The user can choose different visual representations accounting for differences in the size of the documents and the availability of information about the physical and logical layout of the documents. We put special emphasis on providing as much transparency as possible to ensure that the user can purposefully improve the readability of a sentence. Several case-studies are presented that show the wide range of applicability of our tool. | false | false | [
"Daniela Oelke",
"David Spretke",
"Andreas Stoffel",
"Daniel A. Keim"
] | [
"BP"
] | [] | [] |
VAST | 2,010 | Visual tools for dynamic analysis of complex situations | 10.1109/VAST.2010.5654451 | This paper presents an interactive interface synchronized with a simulation framework for exploring complex scenarios. This interface exploits visual analysis for facilitating the understanding of complex situation by human users. | false | false | [
"Marielle Mokhtari",
"Eric Boivin",
"Denis Laurendeau",
"Maxime Girardin"
] | [] | [] | [] |
VAST | 2,010 | Visualization of temporal relationships within coordinated views | 10.1109/VAST.2010.5651617 | In command and control (C2) environments, decision makers must rapidly understand and address key temporal relationships that exist between critical tasks as conditions fluctuate. However, traditional temporal displays, such as mission timelines, fail to support user understanding of and reasoning about critical relationships. We have developed visualization methods to compactly and effectively convey key temporal constraints. In this paper, we present examples of our visualization approach and describe how we are exploring interaction methods within an integrated visualization workspace to support user awareness of temporal constraints. | false | false | [
"Stephanie Dudzic",
"J. Alex Godwin",
"Ryan M. Kilgore"
] | [] | [] | [] |
VAST | 2,010 | Visually representing geo-temporal differences | 10.1109/VAST.2010.5652951 | Data sets that contain geospatial and temporal elements can be challenging to analyze. In particular, it can be difficult to determine how the data have changed over spatial and temporal ranges. In this poster, we present a visual approach for representing the pair-wise differences between geographically and temporally binned data. In addition to providing a novel method for visualizing such geo-temporal differences, GTdiff provides a high degree of interactivity that supports the exploration and analysis of the data. | false | false | [
"Orland Hoeber",
"Garnett Carl Wilson",
"Simon Harding",
"René Enguehard",
"Rodolphe Devillers"
] | [] | [] | [] |
VAST | 2,010 | VizCept: Supporting synchronous collaboration for constructing visualizations in intelligence analysis | 10.1109/VAST.2010.5652932 | In this paper, we present a new web-based visual analytics system, VizCept, which is designed to support fluid, collaborative analysis of large textual intelligence datasets. The main approach of the design is to combine individual workspace and shared visualization in an integrated environment. Collaborating analysts will be able to identify concepts and relationships from the dataset based on keyword searches in their own workspace and collaborate visually with other analysts using visualization tools such as a concept map view and a timeline view. The system allows analysts to parallelize the work by dividing initial sets of concepts, investigating them on their own workspace, and then integrating individual findings automatically on shared visualizations with support for interaction and personal graph layout in real time, in order to develop a unified plot. We highlight several design considerations that promote communication and analytic performance in small team synchronous collaboration. We report the result of a pair of case study applications including collaboration and communication methods, analysis strategies, and user behaviors under a competition setting in the same location at the same time. The results of these demonstrate the tool's effectiveness for synchronous collaborative construction and use of visualizations in intelligence data analysis. | false | false | [
"Haeyong Chung",
"Seungwon Yang",
"Naveed Massjouni",
"Christopher Andrews",
"Rahul Kanna",
"Chris North 0001"
] | [] | [] | [] |
InfoVis | 2,010 | A Visual Backchannel for Large-Scale Events | 10.1109/TVCG.2010.129 | We introduce the concept of a Visual Backchannel as a novel way of following and exploring online conversations about large-scale events. Microblogging communities, such as Twitter, are increasingly used as digital backchannels for timely exchange of brief comments and impressions during political speeches, sport competitions, natural disasters, and other large events. Currently, shared updates are typically displayed in the form of a simple list, making it difficult to get an overview of the fast-paced discussions as it happens in the moment and how it evolves over time. In contrast, our Visual Backchannel design provides an evolving, interactive, and multi-faceted visual overview of large-scale ongoing conversations on Twitter. To visualize a continuously updating information stream, we include visual saliency for what is happening now and what has just happened, set in the context of the evolving conversation. As part of a fully web-based coordinated-view system we introduce Topic Streams, a temporally adjustable stacked graph visualizing topics over time, a People Spiral representing participants and their activity, and an Image Cloud encoding the popularity of event photos by size. Together with a post listing, these mutually linked views support cross-filtering along topics, participants, and time ranges. We discuss our design considerations, in particular with respect to evolving visualizations of dynamically changing data. Initial feedback indicates significant interest and suggests several unanticipated uses. | false | false | [
"Marian Dörk",
"Dan Gruen",
"Carey L. Williamson",
"Sheelagh Carpendale"
] | [] | [] | [] |
InfoVis | 2,010 | An Extension of Wilkinson's Algorithm for Positioning Tick Labels on Axes | 10.1109/TVCG.2010.130 | The non-data components of a visualization, such as axes and legends, can often be just as important as the data itself. They provide contextual information essential to interpreting the data. In this paper, we describe an automated system for choosing positions and labels for axis tick marks. Our system extends Wilkinson's optimization-based labeling approach to create a more robust, full-featured axis labeler. We define an expanded space of axis labelings by automatically generating additional nice numbers as needed and by permitting the extreme labels to occur inside the data range. These changes provide flexibility in problematic cases, without degrading quality elsewhere. We also propose an additional optimization criterion, legibility, which allows us to simultaneously optimize over label formatting, font size, and orientation. To solve this revised optimization problem, we describe the optimization function and an efficient search algorithm. Finally, we compare our method to previous work using both quantitative and qualitative metrics. This paper is a good example of how ideas from automated graphic design can be applied to information visualization. | false | false | [
"Justin Talbot",
"Sharon Lin",
"Pat Hanrahan"
] | [] | [] | [] |
InfoVis | 2,010 | behaviorism: a framework for dynamic data visualization | 10.1109/TVCG.2010.126 | While a number of information visualization software frameworks exist, creating new visualizations, especially those that involve novel visualization metaphors, interaction techniques, data analysis strategies, and specialized rendering algorithms, is still often a difficult process. To facilitate the creation of novel visualizations we present a new software framework, behaviorism, which provides a wide range of flexibility when working with dynamic information on visual, temporal, and ontological levels, but at the same time providing appropriate abstractions which allow developers to create prototypes quickly which can then easily be turned into robust systems. The core of the framework is a set of three interconnected graphs, each with associated operators: a scene graph for high-performance 3D rendering, a data graph for different layers of semantically-linked heterogeneous data, and a timing graph for sophisticated control of scheduling, interaction, and animation. In particular, the timing graph provides a unified system to add behaviors to both data and visual elements, as well as to the behaviors themselves. To evaluate the framework we look briefly at three different projects all of which required novel visualizations in different domains, and all of which worked with dynamic data in different ways: an interactive ecological simulation, an information art installation, and an information visualization technique. | false | false | [
"Angus G. Forbes",
"Tobias Höllerer",
"George Legrady"
] | [] | [] | [] |
InfoVis | 2,010 | Comparative Analysis of Multidimensional; Quantitative Data | 10.1109/TVCG.2010.138 | When analyzing multidimensional, quantitative data, the comparison of two or more groups of dimensions is a common task. Typical sources of such data are experiments in biology, physics or engineering, which are conducted in different configurations and use replicates to ensure statistically significant results. One common way to analyze this data is to filter it using statistical methods and then run clustering algorithms to group similar values. The clustering results can be visualized using heat maps, which show differences between groups as changes in color. However, in cases where groups of dimensions have an a priori meaning, it is not desirable to cluster all dimensions combined, since a clustering algorithm can fragment continuous blocks of records. Furthermore, identifying relevant elements in heat maps becomes more difficult as the number of dimensions increases. To aid in such situations, we have developed Matchmaker, a visualization technique that allows researchers to arbitrarily arrange and compare multiple groups of dimensions at the same time. We create separate groups of dimensions which can be clustered individually, and place them in an arrangement of heat maps reminiscent of parallel coordinates. To identify relations, we render bundled curves and ribbons between related records in different groups. We then allow interactive drill-downs using enlarged detail views of the data, which enable in-depth comparisons of clusters between groups. To reduce visual clutter, we minimize crossings between the views. This paper concludes with two case studies. The first demonstrates the value of our technique for the comparison of clustering algorithms. In the second, biologists use our system to investigate why certain strains of mice develop liver disease while others remain healthy, informally showing the efficacy of our system when analyzing multidimensional data containing distinct groups of dimensions. | false | false | [
"Alexander Lex",
"Marc Streit",
"Christian Partl",
"Karl Kashofer",
"Dieter Schmalstieg"
] | [] | [] | [] |
InfoVis | 2,010 | Declarative Language Design for Interactive Visualization | 10.1109/TVCG.2010.144 | We investigate the design of declarative, domain-specific languages for constructing interactive visualizations. By separating specification from execution, declarative languages can simplify development, enable unobtrusive optimization, and support retargeting across platforms. We describe the design of the Protovis specification language and its implementation within an object-oriented, statically-typed programming language (Java). We demonstrate how to support rich visualizations without requiring a toolkit-specific data model and extend Protovis to enable declarative specification of animated transitions. To support cross-platform deployment, we introduce rendering and event-handling infrastructures decoupled from the runtime platform, letting designers retarget visualization specifications (e.g., from desktop to mobile phone) with reduced effort. We also explore optimizations such as runtime compilation of visualization specifications, parallelized execution, and hardware-accelerated rendering. We present benchmark studies measuring the performance gains provided by these optimizations and compare performance to existing Java-based visualization tools, demonstrating scalability improvements exceeding an order of magnitude. | false | false | [
"Jeffrey Heer",
"Michael Bostock"
] | [
"HM"
] | [] | [] |
InfoVis | 2,010 | eSeeTrack—Visualizing Sequential fixation Patterns | 10.1109/TVCG.2010.149 | We introduce eSeeTrack, an eye-tracking visualization prototype that facilitates exploration and comparison of sequential gaze orderings in a static or a dynamic scene. It extends current eye-tracking data visualizations by extracting patterns of sequential gaze orderings, displaying these patterns in a way that does not depend on the number of fixations on a scene, and enabling users to compare patterns from two or more sets of eye-gaze data. Extracting such patterns was very difficult with previous visualization techniques. eSeeTrack combines a timeline and a tree-structured visual representation to embody three aspects of eye-tracking data that users are interested in: duration, frequency and orderings of fixations. We demonstrate the usefulness of eSeeTrack via two case studies on surgical simulation and retail store chain data. We found that eSeeTrack allows ordering of fixations to be rapidly queried, explored and compared. Furthermore, our tool provides an effective and efficient mechanism to determine pattern outliers. This approach can be effective for behavior analysis in a variety of domains that are described at the end of this paper. | false | false | [
"Hoi Ying Tsang",
"Melanie Tory",
"Colin Swindells"
] | [] | [] | [] |
InfoVis | 2,010 | Evaluating the impact of task demands and block resolution on the effectiveness of pixel-based visualization | 10.1109/TVCG.2010.150 | Pixel-based visualization is a popular method of conveying large amounts of numerical data graphically. Application scenarios include business and finance, bioinformatics and remote sensing. In this work, we examined how the usability of such visual representations varied across different tasks and block resolutions. The main stimuli consisted of temporal pixel-based visualization with a white-red color map, simulating monthly temperature variation over a six-year period. In the first study, we included 5 separate tasks to exert different perceptual loads. We found that performance varied considerably as a function of task, ranging from 75% correct in low-load tasks to below 40% in high-load tasks. There was a small but consistent effect of resolution, with the uniform patch improving performance by around 6% relative to higher block resolution. In the second user study, we focused on a high-load task for evaluating month-to-month changes across different regions of the temperature range. We tested both CIE L*u*v* and RGB color spaces. We found that the nature of the change-evaluation errors related directly to the distance between the compared regions in the mapped color space. We were able to reduce such errors by using multiple color bands for the same data range. In a final study, we examined more fully the influence of block resolution on performance, and found block resolution had a limited impact on the effectiveness of pixel-based visualization. | false | false | [
"Rita Borgo",
"Karl J. Proctor",
"Min Chen 0001",
"Heike Leitte",
"Tavi Murray",
"Ian M. Thornton"
] | [] | [] | [] |
InfoVis | 2,010 | FacetAtlas: Multifaceted Visualization for Rich Text Corpora | 10.1109/TVCG.2010.154 | Documents in rich text corpora usually contain multiple facets of information. For example, an article about a specific disease often consists of different facets such as symptom, treatment, cause, diagnosis, prognosis, and prevention. Thus, documents may have different relations based on different facets. Powerful search tools have been developed to help users locate lists of individual documents that are most related to specific keywords. However, there is a lack of effective analysis tools that reveal the multifaceted relations of documents within or cross the document clusters. In this paper, we present FacetAtlas, a multifaceted visualization technique for visually analyzing rich text corpora. FacetAtlas combines search technology with advanced visual analytical tools to convey both global and local patterns simultaneously. We describe several unique aspects of FacetAtlas, including (1) node cliques and multifaceted edges, (2) an optimized density map, and (3) automated opacity pattern enhancement for highlighting visual patterns, (4) interactive context switch between facets. In addition, we demonstrate the power of FacetAtlas through a case study that targets patient education in the health care domain. Our evaluation shows the benefits of this work, especially in support of complex multifaceted data analysis. | false | false | [
"Nan Cao",
"Jimeng Sun 0001",
"Yu-Ru Lin",
"David Gotz",
"Shixia Liu",
"Huamin Qu"
] | [] | [] | [] |
InfoVis | 2,010 | GeneaQuilts: A System for Exploring Large Genealogies | 10.1109/TVCG.2010.159 | GeneaQuilts is a new visualization technique for representing large genealogies of up to several thousand individuals. The visualization takes the form of a diagonally-filled matrix, where rows are individuals and columns are nuclear families. After identifying the major tasks performed in genealogical research and the limits of current software, we present an interactive genealogy exploration system based on GeneaQuilts. The system includes an overview, a timeline, search and filtering components, and a new interaction technique called Bring & Slide that allows fluid navigation in very large genealogies. We report on preliminary feedback from domain experts and show how our system supports a number of their tasks. | false | false | [
"Anastasia Bezerianos",
"Pierre Dragicevic",
"Jean-Daniel Fekete",
"Juhee Bae",
"Benjamin Watson 0001"
] | [] | [] | [] |
InfoVis | 2,010 | Graphical inference for infovis | 10.1109/TVCG.2010.161 | How do we know if what we see is really there? When visualizing data, how do we avoid falling into the trap of apophenia where we see patterns in random noise? Traditionally, infovis has been concerned with discovering new relationships, and statistics with preventing spurious relationships from being reported. We pull these opposing poles closer with two new techniques for rigorous statistical inference of visual discoveries. The "Rorschach" helps the analyst calibrate their understanding of uncertainty and "line-up" provides a protocol for assessing the significance of visual discoveries, protecting against the discovery of spurious structure. | false | false | [
"Hadley Wickham",
"Dianne Cook",
"Heike Hofmann",
"Andreas Buja"
] | [
"BP"
] | [] | [] |
InfoVis | 2,010 | Graphical Perception of Multiple Time Series | 10.1109/TVCG.2010.162 | Line graphs have been the visualization of choice for temporal data ever since the days of William Playfair (1759-1823), but realistic temporal analysis tasks often include multiple simultaneous time series. In this work, we explore user performance for comparison, slope, and discrimination tasks for different line graph techniques involving multiple time series. Our results show that techniques that create separate charts for each time series--such as small multiples and horizon graphs--are generally more efficient for comparisons across time series with a large visual span. On the other hand, shared-space techniques--like standard line graphs--are typically more efficient for comparisons over smaller visual spans where the impact of overlap and clutter is reduced. | false | false | [
"Waqas Javed",
"Bryan McDonnel",
"Niklas Elmqvist"
] | [] | [] | [] |
InfoVis | 2,010 | Gremlin: An Interactive Visualization Model for Analyzing Genomic Rearrangements | 10.1109/TVCG.2010.163 | In this work we present, apply, and evaluate a novel, interactive visualization model for comparative analysis of structural variants and rearrangements in human and cancer genomes, with emphasis on data integration and uncertainty visualization. To support both global trend analysis and local feature detection, this model enables explorations continuously scaled from the high-level, complete genome perspective, down to the low-level, structural rearrangement view, while preserving global context at all times. We have implemented these techniques in Gremlin, a genomic rearrangement explorer with multi-scale, linked interactions, which we apply to four human cancer genome data sets for evaluation. Using an insight-based evaluation methodology, we compare Gremlin to Circos, the state-of-the-art in genomic rearrangement visualization, through a small user study with computational biologists working in rearrangement analysis. Results from user study evaluations demonstrate that this visualization model enables more total insights, more insights per minute, and more complex insights than the current state-of-the-art for visual analysis and exploration of genome rearrangements. | false | false | [
"Trevor M. O'Brien",
"Anna M. Ritz",
"Benjamin J. Raphael",
"David H. Laidlaw"
] | [] | [] | [] |
InfoVis | 2,010 | How Information Visualization Novices Construct Visualizations | 10.1109/TVCG.2010.164 | It remains challenging for information visualization novices to rapidly construct visualizations during exploratory data analysis. We conducted an exploratory laboratory study in which information visualization novices explored fictitious sales data by communicating visualization specifications to a human mediator, who rapidly constructed the visualizations using commercial visualization software. We found that three activities were central to the iterative visualization construction process: data attribute selection, visual template selection, and visual mapping specification. The major barriers faced by the participants were translating questions into data attributes, designing visual mappings, and interpreting the visualizations. Partial specification was common, and the participants used simple heuristics and preferred visualizations they were already familiar with, such as bar, line and pie charts. We derived abstract models from our observations that describe barriers in the data exploration process and uncovered how information visualization novices think about visualization specifications. Our findings support the need for tools that suggest potential visualizations and support iterative refinement, that provide explanations and help with learning, and that are tightly integrated into tool support for the overall visual analytics process. | false | false | [
"Lars Grammel",
"Melanie Tory",
"Margaret-Anne D. Storey"
] | [] | [] | [] |
InfoVis | 2,010 | Laws of Attraction: From Perceptual Forces to Conceptual Similarity | 10.1109/TVCG.2010.174 | Many of the pressing questions in information visualization deal with how exactly a user reads a collection of visual marks as information about relationships between entities. Previous research has suggested that people see parts of a visualization as objects, and may metaphorically interpret apparent physical relationships between these objects as suggestive of data relationships. We explored this hypothesis in detail in a series of user experiments. Inspired by the concept of implied dynamics in psychology, we first studied whether perceived gravity acting on a mark in a scatterplot can lead to errors in a participant's recall of the mark's position. The results of this study suggested that such position errors exist, but may be more strongly influenced by attraction between marks. We hypothesized that such apparent attraction may be influenced by elements used to suggest relationship between objects, such as connecting lines, grouping elements, and visual similarity. We further studied what visual elements are most likely to cause this attraction effect, and whether the elements that best predicted attraction errors were also those which suggested conceptual relationships most strongly. Our findings show a correlation between attraction errors and intuitions about relatedness, pointing towards a possible mechanism by which the perception of visual marks becomes an interpretation of data relationships. | false | false | [
"Caroline Ziemkiewicz",
"Robert Kosara"
] | [] | [] | [] |
InfoVis | 2,010 | ManiWordle: Providing Flexible Control over Wordle | 10.1109/TVCG.2010.175 | Among the multifarious tag-clouding techniques, Wordle stands out to the community by providing an aesthetic layout, eliciting the emergence of the participatory culture and usage of tag-clouding in the artistic creations. In this paper, we introduce ManiWordle, a Wordle-based visualization tool that revamps interactions with the layout by supporting custom manipulations. ManiWordle allows people to manipulate typography, color, and composition not only for the layout as a whole, but also for the individual words, enabling them to have better control over the layout result. We first describe our design rationale along with the interaction techniques for tweaking the layout. We then present the results both from the preliminary usability study and from the comparative study between ManiWordle and Wordle. The results suggest that ManiWordle provides higher user satisfaction and an efficient method of creating the desired "art work," harnessing the power behind the ever-increasing popularity of Wordle. | false | false | [
"Kyle Koh",
"Bongshin Lee",
"Bo Hyoung Kim",
"Jinwook Seo"
] | [] | [] | [] |
InfoVis | 2,010 | Matching Visual Saliency to Confidence in Plots of Uncertain Data | 10.1109/TVCG.2010.176 | Conveying data uncertainty in visualizations is crucial for preventing viewers from drawing conclusions based on untrustworthy data points. This paper proposes a methodology for efficiently generating density plots of uncertain multivariate data sets that draws viewers to preattentively identify values of high certainty while not calling attention to uncertain values. We demonstrate how to augment scatter plots and parallel coordinates plots to incorporate statistically modeled uncertainty and show how to integrate them with existing multivariate analysis techniques, including outlier detection and interactive brushing. Computing high quality density plots can be expensive for large data sets, so we also describe a probabilistic plotting technique that summarizes the data without requiring explicit density plot computation. These techniques have been useful for identifying brain tumors in multivariate magnetic resonance spectroscopy data and we describe how to extend them to visualize ensemble data sets. | false | false | [
"David Feng 0001",
"Lester Kwock",
"Yueh Z. Lee",
"Russell M. Taylor II"
] | [] | [] | [] |
InfoVis | 2,010 | Mental Models; Visual Reasoning and Interaction in Information Visualization: A Top-down Perspective | 10.1109/TVCG.2010.177 | Although previous research has suggested that examining the interplay between internal and external representations can benefit our understanding of the role of information visualization (InfoVis) in human cognitive activities, there has been little work detailing the nature of internal representations, the relationship between internal and external representations and how interaction is related to these representations. In this paper, we identify and illustrate a specific kind of internal representation, mental models, and outline the high-level relationships between mental models and external visualizations. We present a top-down perspective of reasoning as model construction and simulation, and discuss the role of visualization in model based reasoning. From this perspective, interaction can be understood as active modeling for three primary purposes: external anchoring, information foraging, and cognitive offloading. Finally we discuss the implications of our approach for design, evaluation and theory development. | false | false | [
"Zhicheng Liu",
"John T. Stasko"
] | [] | [] | [] |
InfoVis | 2,010 | MulteeSum: A Tool for Comparative Spatial and Temporal Gene Expression Data | 10.1109/TVCG.2010.137 | Cells in an organism share the same genetic information in their DNA, but have very different forms and behavior because of the selective expression of subsets of their genes. The widely used approach of measuring gene expression over time from a tissue sample using techniques such as microarrays or sequencing do not provide information about the spatial position with in the tissue where these genes are expressed. In contrast, we are working with biologists who use techniques that measure gene expression in every individual cell of entire fruitfly embryos over an hour of their development, and do so for multiple closely-related subspecies of Drosophila. These scientists are faced with the challenge of integrating temporal gene expression data with the spatial location of cells and, moreover, comparing this data across multiple related species. We have worked with these biologists over the past two years to develop MulteeSum, a visualization system that supports inspection and curation of data sets showing gene expression over time, in conjunction with the spatial location of the cells where the genes are expressed - it is the first tool to support comparisons across multiple such data sets. MulteeSum is part of a general and flexible framework we developed with our collaborators that is built around multiple summaries for each cell, allowing the biologists to explore the results of computations that mix spatial information, gene expression measurements over time, and data from multiple related species or organisms. We justify our design decisions based on specific descriptions of the analysis needs of our collaborators, and provide anecdotal evidence of the efficacy of MulteeSum through a series of case studies. | false | false | [
"Miriah D. Meyer",
"Tamara Munzner",
"Angela H. DePace",
"Hanspeter Pfister"
] | [] | [] | [] |
InfoVis | 2,010 | Narrative Visualization: Telling Stories with Data | 10.1109/TVCG.2010.179 | Data visualization is regularly promoted for its ability to reveal stories within data, yet these “data stories” differ in important ways from traditional forms of storytelling. Storytellers, especially online journalists, have increasingly been integrating visualizations into their narratives, in some cases allowing the visualization to function in place of a written story. In this paper, we systematically review the design space of this emerging class of visualizations. Drawing on case studies from news media to visualization research, we identify distinct genres of narrative visualization. We characterize these design differences, together with interactivity and messaging, in terms of the balance between the narrative flow intended by the author (imposed by graphical elements and the interface) and story discovery on the part of the reader (often through interactive exploration). Our framework suggests design strategies for narrative visualization, including promising under-explored approaches to journalistic storytelling and educational media. | false | false | [
"Edward Segel",
"Jeffrey Heer"
] | [
"TT"
] | [] | [] |
InfoVis | 2,010 | Necklace Maps | 10.1109/TVCG.2010.180 | Statistical data associated with geographic regions is nowadays globally available in large amounts and hence automated methods to visually display these data are in high demand. There are several well-established thematic map types for quantitative data on the ratio-scale associated with regions: choropleth maps, cartograms, and proportional symbol maps. However, all these maps suffer from limitations, especially if large data values are associated with small regions. To overcome these limitations, we propose a novel type of quantitative thematic map, the necklace map. In a necklace map, the regions of the underlying two-dimensional map are projected onto intervals on a one-dimensional curve (the necklace) that surrounds the map regions. Symbols are scaled such that their area corresponds to the data of their region and placed without overlap inside the corresponding interval on the necklace. Necklace maps appear clear and uncluttered and allow for comparatively large symbol sizes. They visualize data sets well which are not proportional to region sizes. The linear ordering of the symbols along the necklace facilitates an easy comparison of symbol sizes. One map can contain several nested or disjoint necklaces to visualize clustered data. The advantages of necklace maps come at a price: the association between a symbol and its region is weaker than with other types of maps. Interactivity can help to strengthen this association if necessary. We present an automated approach to generate necklace maps which allows the user to interactively control the final symbol placement. We validate our approach with experiments using various data sets and maps. | false | false | [
"Bettina Speckmann",
"Kevin Verbeek"
] | [
"HM"
] | [] | [] |
InfoVis | 2,010 | OpinionSeer: Interactive Visualization of Hotel Customer Feedback | 10.1109/TVCG.2010.183 | The rapid development of Web technology has resulted in an increasing number of hotel customers sharing their opinions on the hotel services. Effective visual analysis of online customer opinions is needed, as it has a significant impact on building a successful business. In this paper, we present OpinionSeer, an interactive visualization system that could visually analyze a large collection of online hotel customer reviews. The system is built on a new visualization-centric opinion mining technique that considers uncertainty for faithfully modeling and analyzing customer opinions. A new visual representation is developed to convey customer opinions by augmenting well-established scatterplots and radial visualization. To provide multiple-level exploration, we introduce subjective logic to handle and organize subjective opinions with degrees of uncertainty. Several case studies illustrate the effectiveness and usefulness of OpinionSeer on analyzing relationships among multiple data dimensions and comparing opinions of different groups. Aside from data on hotel customer feedback, OpinionSeer could also be applied to visually analyze customer opinions on other products or services. | false | false | [
"Yingcai Wu",
"Furu Wei",
"Shixia Liu",
"Norman Au",
"Weiwei Cui",
"Hong Zhou 0004",
"Huamin Qu"
] | [] | [] | [] |
InfoVis | 2,010 | Pargnostics: Screen-Space Metrics for Parallel Coordinates | 10.1109/TVCG.2010.184 | Interactive visualization requires the translation of data into a screen space of limited resolution. While currently ignored by most visualization models, this translation entails a loss of information and the introduction of a number of artifacts that can be useful, (e.g., aggregation, structures) or distracting (e.g., over-plotting, clutter) for the analysis. This phenomenon is observed in parallel coordinates, where overlapping lines between adjacent axes form distinct patterns, representing the relation between variables they connect. However, even for a small number of dimensions, the challenge is to effectively convey the relationships for all combinations of dimensions. The size of the dataset and a large number of dimensions only add to the complexity of this problem. To address these issues, we propose Pargnostics, parallel coordinates diagnostics, a model based on screen-space metrics that quantify the different visual structures. Pargnostics metrics are calculated for pairs of axes and take into account the resolution of the display as well as potential axis inversions. Metrics include the number of line crossings, crossing angles, convergence, overplotting, etc. To construct a visualization view, the user can pick from a ranked display showing pairs of coordinate axes and the structures between them, or examine all possible combinations of axes at once in a matrix display. Picking the best axes layout is an NP-complete problem in general, but we provide a way of automatically optimizing the display according to the user's preferences based on our metrics and model. | false | false | [
"Aritra Dasgupta",
"Robert Kosara"
] | [] | [] | [] |
InfoVis | 2,010 | PedVis: A Structured; Space-Efficient Technique for Pedigree Visualization | 10.1109/TVCG.2010.185 | Public genealogical databases are becoming increasingly populated with historical data and records of the current population's ancestors. As this increasing amount of available information is used to link individuals to their ancestors, the resulting trees become deeper and more dense, which justifies the need for using organized, space-efficient layouts to display the data. Existing layouts are often only able to show a small subset of the data at a time. As a result, it is easy to become lost when navigating through the data or to lose sight of the overall tree structure. On the contrary, leaving space for unknown ancestors allows one to better understand the tree's structure, but leaving this space becomes expensive and allows fewer generations to be displayed at a time. In this work, we propose that the H-tree based layout be used in genealogical software to display ancestral trees. We will show that this layout presents an increase in the number of displayable generations, provides a nicely arranged, symmetrical, intuitive and organized fractal structure, increases the user's ability to understand and navigate through the data, and accounts for the visualization requirements necessary for displaying such trees. Finally, user-study results indicate potential for user acceptance of the new layout. | false | false | [
"Claurissa Tuttle",
"Luis Gustavo Nonato",
"Cláudio T. Silva"
] | [] | [] | [] |
InfoVis | 2,010 | Perceptual Guidelines for Creating Rectangular Treemaps | 10.1109/TVCG.2010.186 | Treemaps are space-filling visualizations that make efficient use of limited display space to depict large amounts of hierarchical data. Creating perceptually effective treemaps requires carefully managing a number of design parameters including the aspect ratio and luminance of rectangles. Moreover, treemaps encode values using area, which has been found to be less accurate than judgments of other visual encodings, such as length. We conduct a series of controlled experiments aimed at producing a set of design guidelines for creating effective rectangular treemaps. We find no evidence that luminance affects area judgments, but observe that aspect ratio does have an effect. Specifically, we find that the accuracy of area comparisons suffers when the compared rectangles have extreme aspect ratios or when both are squares. Contrary to common assumptions, the optimal distribution of rectangle aspect ratios within a treemap should include non-squares, but should avoid extremes. We then compare treemaps with hierarchical bar chart displays to identify the data densities at which length-encoded bar charts become less effective than area-encoded treemaps. We report the transition points at which treemaps exhibit judgment accuracy on par with bar charts for both leaf and non-leaf tree nodes. We also find that even at relatively low data densities treemaps result in faster comparisons than bar charts. Based on these results, we present a set of guidelines for the effective use of treemaps and suggest alternate approaches for treemap layout. | false | false | [
"Nicholas Kong",
"Jeffrey Heer",
"Maneesh Agrawala"
] | [
"HM"
] | [] | [] |
InfoVis | 2,010 | Rethinking Map Legends with Visualization | 10.1109/TVCG.2010.191 | This design paper presents new guidance for creating map legends in a dynamic environment. Our contribution is a set ofguidelines for legend design in a visualization context and a series of illustrative themes through which they may be expressed. Theseare demonstrated in an applications context through interactive software prototypes. The guidelines are derived from cartographicliterature and in liaison with EDINA who provide digital mapping services for UK tertiary education. They enhance approaches tolegend design that have evolved for static media with visualization by considering: selection, layout, symbols, position, dynamismand design and process. Broad visualization legend themes include: The Ground Truth Legend, The Legend as Statistical Graphicand The Map is the Legend. Together, these concepts enable us to augment legends with dynamic properties that address specificneeds, rethink their nature and role and contribute to a wider re-evaluation of maps as artifacts of usage rather than statements offact. EDINA has acquired funding to enhance their clients with visualization legends that use these concepts as a consequence ofthis work. The guidance applies to the design of a wide range of legends and keys used in cartography and information visualization. | false | false | [
"Jason Dykes",
"Jo Wood",
"Aidan Slingsby"
] | [
"HM"
] | [] | [] |
InfoVis | 2,010 | SignalLens: Focus+Context Applied to Electronic Time Series | 10.1109/TVCG.2010.193 | Electronic test and measurement systems are becoming increasingly sophisticated in order to match the increased complexity and ultra-high speed of the devices under test. A key feature in many such instruments is a vastly increased capacity for storage of digital signals. Storage of 109 time points or more is now possible. At the same time, the typical screens on such measurement devices are relatively small. Therefore, these instruments can only render an extremely small fraction of the complete signal at any time. SignalLens uses a Focus+Context approach to provide a means of navigating to and inspecting low-level signal details in the context of the entire signal trace. This approach provides a compact visualization suitable for embedding into the small displays typically provided by electronic measurement instruments. We further augment this display with computed tracks which display time-aligned computed properties of the signal. By combining and filtering these computed tracks it is possible to easily and quickly find computationally detected features in the data which are often obscured by the visual compression required to render the large data sets on a small screen. Further, these tracks can be viewed in the context of the entire signal trace as well as visible high-level signal features. Several examples using real-world electronic measurement data are presented, which demonstrate typical use cases and the effectiveness of the design. | false | false | [
"Robert Kincaid"
] | [
"HM"
] | [] | [] |
InfoVis | 2,010 | SparkClouds: Visualizing Trends in Tag Clouds | 10.1109/TVCG.2010.194 | Tag clouds have proliferated over the web over the last decade. They provide a visual summary of a collection of texts by visually depicting the tag frequency by font size. In use, tag clouds can evolve as the associated data source changes over time. Interesting discussions around tag clouds often include a series of tag clouds and consider how they evolve over time. However, since tag clouds do not explicitly represent trends or support comparisons, the cognitive demands placed on the person for perceiving trends in multiple tag clouds are high. In this paper, we introduce SparkClouds, which integrate sparklines into a tag cloud to convey trends between multiple tag clouds. We present results from a controlled study that compares SparkClouds with two traditional trend visualizations-multiple line graphs and stacked bar charts-as well as Parallel Tag Clouds. Results show that SparkClouds' ability to show trends compares favourably to the alternative visualizations. | false | false | [
"Bongshin Lee",
"Nathalie Henry Riche",
"Amy K. Karlson",
"Sheelagh Carpendale"
] | [] | [] | [] |
InfoVis | 2,010 | Stacking Graphic Elements to Avoid Over-Plotting | 10.1109/TVCG.2010.197 | An ongoing challenge for information visualization is how to deal with over-plotting forced by ties or the relatively limited visual field of display devices. A popular solution is to represent local data density with area (bubble plots, treemaps), color(heatmaps), or aggregation (histograms, kernel densities, pixel displays). All of these methods have at least one of three deficiencies:1) magnitude judgments are biased because area and color have convex downward perceptual functions, 2) area, hue, and brightnesshave relatively restricted ranges of perceptual intensity compared to length representations, and/or 3) it is difficult to brush or link toindividual cases when viewing aggregations. In this paper, we introduce a new technique for visualizing and interacting with datasets that preserves density information by stacking overlapping cases. The overlapping data can be points or lines or other geometric elements, depending on the type of plot. We show real-dataset applications of this stacking paradigm and compare them to other techniques that deal with over-plotting in high-dimensional displays. | false | false | [
"Tommy Dang",
"Leland Wilkinson",
"Anushka Anand"
] | [] | [] | [] |
InfoVis | 2,010 | The FlowVizMenu and Parallel Scatterplot Matrix: Hybrid Multidimensional Visualizations for Network Exploration | 10.1109/TVCG.2010.205 | A standard approach for visualizing multivariate networks is to use one or more multidimensional views (for example, scatterplots) for selecting nodes by various metrics, possibly coordinated with a node-link view of the network. In this paper, we present three novel approaches for achieving a tighter integration of these views through hybrid techniques for multidimensional visualization, graph selection and layout. First, we present the FlowVizMenu, a radial menu containing a scatterplot that can be popped up transiently and manipulated with rapid, fluid gestures to select and modify the axes of its scatterplot. Second, the FlowVizMenu can be used to steer an attribute-driven layout of the network, causing certain nodes of a node-link diagram to move toward their corresponding positions in a scatterplot while others can be positioned manually or by force-directed layout. Third, we describe a novel hybrid approach that combines a scatterplot matrix (SPLOM) and parallel coordinates called the Parallel Scatterplot Matrix (P-SPLOM), which can be used to visualize and select features within the network. We also describe a novel arrangement of scatterplots called the Scatterplot Staircase (SPLOS) that requires less space than a traditional scatterplot matrix. Initial user feedback is reported. | false | false | [
"Christophe Viau",
"Michael J. McGuffin",
"Yves Chiricota",
"Igor Jurisica"
] | [] | [] | [] |
InfoVis | 2,010 | The Streams of Our Lives: Visualizing Listening Histories in Context | 10.1109/TVCG.2010.206 | The choices we take when listening to music are expressions of our personal taste and character. Storing and accessing our listening histories is trivial due to services like Last.fm, but learning from them and understanding them is not. Existing solutions operate at a very abstract level and only produce statistics. By applying techniques from information visualization to this problem, we were able to provide average people with a detailed and powerful tool for accessing their own musical past. LastHistory is an interactive visualization for displaying music listening histories, along with contextual information from personal photos and calendar entries. Its two main user tasks are (1) analysis, with an emphasis on temporal patterns and hypotheses related to musical genre and sequences, and (2) reminiscing, where listening histories and context represent part of one's past. In this design study paper we give an overview of the field of music listening histories and explain their unique characteristics as a type of personal data. We then describe the design rationale, data and view transformations of LastHistory and present the results from both a laband a large-scale online study. We also put listening histories in contrast to other lifelogging data. The resonant and enthusiastic feedback that we received from average users shows a need for making their personal data accessible. We hope to stimulate such developments through this research. | false | false | [
"Dominikus Baur",
"Frederik Seiffert",
"Michael Sedlmair",
"Sebastian Boring"
] | [] | [] | [] |
InfoVis | 2,010 | Uncovering Strengths and Weaknesses of Radial Visualizations---an Empirical Approach | 10.1109/TVCG.2010.209 | Radial visualizations play an important role in the information visualization community. But the decision to choose a radial coordinate system is rather based on intuition than on scientific foundations. The empirical approach presented in this paper aims at uncovering strengths and weaknesses of radial visualizations by comparing them to equivalent ones in Cartesian coordinate systems. We identified memorizing positions of visual elements as a generic task when working with visualizations. A first study with 674 participants provides a broad data spectrum for exploring differences between the two visualization types. A second, complementing study with fewer participants focuses on further questions raised by the first study. Our findings document that Cartesian visualizations tend to outperform their radial counterparts especially with respect to answer times. Nonetheless, radial visualization seem to be more appropriate for focusing on a particular data dimension. | false | false | [
"Stephan Diehl 0001",
"Fabian Beck 0001",
"Michael Burch"
] | [] | [] | [] |
InfoVis | 2,010 | Untangling Euler Diagrams | 10.1109/TVCG.2010.210 | In many common data analysis scenarios the data elements are logically grouped into sets. Venn and Euler style diagrams are a common visual representation of such set membership where the data elements are represented by labels or glyphs and sets are indicated by boundaries surrounding their members. Generating such diagrams automatically such that set regions do not intersect unless the corresponding sets have a non-empty intersection is a difficult problem. Further, it may be impossible in some cases if regions are required to be continuous and convex. Several approaches exist to draw such set regions using more complex shapes, however, the resulting diagrams can be difficult to interpret. In this paper we present two novel approaches for simplifying a complex collection of intersecting sets into a strict hierarchy that can be more easily automatically arranged and drawn (Figure 1). In the first approach, we use compact rectangular shapes for drawing each set, attempting to improve the readability of the set intersections. In the second approach, we avoid drawing intersecting set regions by duplicating elements belonging to multiple sets. We compared both of our techniques to the traditional non-convex region technique using five readability tasks. Our results show that the compact rectangular shapes technique was often preferred by experimental subjects even though the use of duplications dramatically improves the accuracy and performance time for most of our tasks. In addition to general set representation our techniques are also applicable to visualization of networks with intersecting clusters of nodes. | false | false | [
"Nathalie Henry Riche",
"Tim Dwyer"
] | [] | [] | [] |
InfoVis | 2,010 | Visualization of Diversity in Large Multivariate Data Sets | 10.1109/TVCG.2010.216 | Understanding the diversity of a set of multivariate objects is an important problem in many domains, including ecology, college admissions, investing, machine learning, and others. However, to date, very little work has been done to help users achieve this kind of understanding. Visual representation is especially appealing for this task because it offers the potential to allow users to efficiently observe the objects of interest in a direct and holistic way. Thus, in this paper, we attempt to formalize the problem of visualizing the diversity of a large (more than 1000 objects), multivariate (more than 5 attributes) data set as one worth deeper investigation by the information visualization community. In doing so, we contribute a precise definition of diversity, a set of requirements for diversity visualizations based on this definition, and a formal user study design intended to evaluate the capacity of a visual representation for communicating diversity information. Our primary contribution, however, is a visual representation, called the Diversity Map, for visualizing diversity. An evaluation of the Diversity Map using our study design shows that users can judge elements of diversity consistently and as or more accurately than when using the only other representation specifically designed to visualize diversity. | false | false | [
"Tuan Pham",
"Rob Hess",
"Crystal Ju",
"Eugene Zhang",
"Ronald A. Metoyer"
] | [] | [] | [] |
InfoVis | 2,010 | Visualization of Graph Products | 10.1109/TVCG.2010.217 | Graphs are a versatile structure and abstraction for binary relationships between objects. To gain insight into such relationships, their corresponding graph can be visualized. In the past, many classes of graphs have been defined, e.g. trees, planar graphs, directed acyclic graphs, and visualization algorithms were proposed for these classes. Although many graphs may only be classified as "general" graphs, they can contain substructures that belong to a certain class. Archambault proposed the TopoLayout framework: rather than draw any arbitrary graph using one method, split the graph into components that are homogeneous with respect to one graph class and then draw each component with an algorithm best suited for this class. Graph products constitute a class that arises frequently in graph theory, but for which no visualization algorithm has been proposed until now. In this paper, we present an algorithm for drawing graph products and the aesthetic criterion graph product's drawings are subject to. We show that the popular High-Dimensional Embedder approach applied to cartesian products already respects this aestetic criterion, but has disadvantages. We also present how our method is integrated as a new component into the TopoLayout framework. Our implementation is used for further research of graph products in a biological context. | false | false | [
"Stefan Jänicke",
"Christian Heine 0002",
"Marc Hellmuth",
"Peter F. Stadler",
"Gerik Scheuermann"
] | [] | [] | [] |
InfoVis | 2,010 | Visualizations everywhere: A Multiplatform Infrastructure for Linked Visualizations | 10.1109/TVCG.2010.222 | In order to use new visualizations, most toolkits require application developers to rebuild their applications and distribute new versions to users. The WebCharts Framework take a different approach by hosting Javascript from within an application and providing a standard data and events interchange.. In this way, applications can be extended dynamically, with a wide variety of visualizations. We discuss the benefits of this architectural approach, contrast it to existing techniques, and give a variety of examples and extensions of the basic system. | false | false | [
"Danyel Fisher",
"Steven Mark Drucker",
"Roland Fernandez",
"Scott Ruble"
] | [] | [] | [] |
EuroVis | 2,010 | A Maximum Enhancing Higher-Order Tensor Glyph | 10.1111/j.1467-8659.2009.01675.x | Glyphs are a fundamental tool in tensor visualization, since they provide an intuitive geometric representation of the full tensor information. The Higher‐Order Maximum Enhancing (HOME) glyph, a generalization of the second‐order tensor ellipsoid, was recently shown to emphasize the orientational information in the tensor through a pointed shape around maxima. This paper states and formally proves several important properties of this novel glyph, presents its first three‐dimensional implementation, and proposes a new coloring scheme that reflects peak direction and sharpness. Application to data from High Angular Resolution Diffusion Imaging (HARDI) shows that the method allows for interactive data exploration and confirms that the HOME glyph conveys fiber spread and crossings more effectively than the conventional polar plot. | false | false | [
"Thomas Schultz 0001",
"Gordon L. Kindlmann"
] | [] | [] | [] |
EuroVis | 2,010 | A Multidirectional Occlusion Shading Model for Direct Volume Rendering | 10.1111/j.1467-8659.2009.01695.x | In this paper, we present a novel technique which simulates directional light scattering for more realistic interactive visualization of volume data. Our method extends the recent directional occlusion shading model by enabling light source positioning with practically no performance penalty. Light transport is approximated using a tilted cone‐shaped function which leaves elliptic footprints in the opacity buffer during slice‐based volume rendering. We perform an incremental blurring operation on the opacity buffer for each slice in front‐to‐back order. This buffer is then used to define the degree of occlusion for the subsequent slice. Our method is capable of generating high‐quality soft shadowing effects, allows interactive modification of all illumination and rendering parameters, and requires no pre‐computation. | false | false | [
"Veronika Soltészová",
"Daniel Patel",
"Stefan Bruckner",
"Ivan Viola"
] | [] | [] | [] |
EuroVis | 2,010 | A Salience-based Quality Metric for Visualization | 10.1111/j.1467-8659.2009.01667.x | Salience detection is a principle mechanism to facilitate visual attention. A good visualization guides the observer's attention to the relevant aspects of the representation. Hence, the distribution of salience over a visualization image is an essential measure of the quality of the visualization. We describe a method for computing such a metric for a visualization image in the context of a given dataset. We show how this technique can be used to analyze a visualization's salience, improve an existing visualization, and choose the best representation from a set of alternatives. The usefulness of this proposed metric is illustrated using examples from information visualization, volume visualization and flow visualization. | false | false | [
"Heike Jänicke",
"Min Chen 0001"
] | [] | [] | [] |
EuroVis | 2,010 | Accelerated Visualization of Dynamic Molecular Surfaces | 10.1111/j.1467-8659.2009.01693.x | Molecular surfaces play an important role in studying the interactions between molecules. Visualizing the dynamic behavior of molecules is particularly interesting to gain insights into a molecular system. Only recently it has become possible to interactively visualize dynamic molecular surfaces using ray casting techniques.In this paper, we show how to further accelerate the construction and the rendering of the solvent excluded surface (SES) and the molecular skin surface (MSS). We propose several improvements to reduce the update times for displaying these molecular surfaces. First, we adopt a parallel approximate Voronoi diagram algorithm to compute the MSS. This accelerates the MSS computation by more than one order of magnitude on a single core. Second, we demonstrate that the contour‐buildup algorithm is ideally suited for computing the SES due to its inherently parallel structure. For both parallel algorithms, we observe good scalability up to 8 cores and, thus, obtain interactive frame rates for molecular dynamics trajectories of up to twenty thousand atoms for the SES and up to a few thousand atoms for the MSS. Third, we reduce the rendering time for the SES using tight‐fitting bounding quadrangles as rasterization primitives. These primitives also accelerate the rendering of the MSS. With these improvements, the interactive visualization of the MSS of dynamic trajectories of a few thousand atoms becomes for the first time possible. Nevertheless, the SES remains a few times faster than the MSS. | false | false | [
"Norbert Lindow",
"Daniel Baum",
"Steffen Prohaska",
"Hans-Christian Hege"
] | [] | [] | [] |
EuroVis | 2,010 | Alleviating the Modifiable Areal Unit Problem within Probe-Based Geospatial Analyses | 10.1111/j.1467-8659.2009.01707.x | We present a probe‐based interface for the exploration of the results of a geospatial simulation of urban growth. Because our interface allows the user great freedom in how they choose to define regions‐of‐interest to examine and compare, the classic geospatial analytic issue known as the modifiable areal unit problem (MAUP) quickly arises. The user may delineate regions with unseen differences that can affect the fairness of the comparisons made between them. To alleviate this problem, our interface first alerts the user if it detects any potential unfairness between regions when they are selected for comparison. It then presents the dimensions with potential problematic outliers to the user for evaluation. Finally, it provides a number of semi‐automated tools to assist the user in correcting their regions' boundaries to minimize the inequalities they feel could significantly impact their comparisons. | false | false | [
"Thomas Butkiewicz",
"Ross K. Meentemeyer",
"Douglas A. Shoemaker",
"Remco Chang",
"Zachary Wartell",
"William Ribarsky"
] | [] | [] | [] |
EuroVis | 2,010 | An Evaluation of Glyph Perception for Real Symmetric Traceless Tensor Properties | 10.1111/j.1467-8659.2009.01711.x | A perceptual study of four tensor glyphs for symmetric, real, traceless tensors was performed. Each glyph encodes three properties of the system: Orientation, uniaxiality (alignment along the direction of orientation), and biaxiality (alignment along a vector orthogonal to the orientation). Thirty users over two studies were asked to identify these three properties for each glyph type under a variety of permutations in order to evaluate the effectiveness of visually communicating the properties; response time was also measured. We discuss the significant differences found between the methods as guidance to the use of these glyphs for traceless tensor visualization. | false | false | [
"T. J. Jankun-Kelly",
"Y. S. Lanka",
"J. Edward Swan II"
] | [] | [] | [] |
EuroVis | 2,010 | An Exploratory Technique for Coherent Visualization of Time-varying Volume Data | 10.1111/j.1467-8659.2009.01690.x | The selection of an appropriate global transfer function is essential for visualizing time‐varying simulation data. This is especially challenging when the global data range is not known in advance, as is often the case in remote and in‐situ visualization settings. Since the data range may vary dramatically as the simulation progresses, volume rendering using local transfer functions may not be coherent for all time steps. We present an exploratory technique that enables coherent classification of time‐varying volume data. Unlike previous approaches, which require pre‐processing of all time steps, our approach lets the user explore the transfer function space without accessing the original 3D data. This is useful for interactive visualization, and absolutely essential for in‐situ visualization, where the entire simulation data range is not known in advance. Our approach generates a compact representation of each time step at rendering time in the form of ray attenuation functions, which are used for subsequent operations on the opacity and color mappings. The presented approach offers interactive exploration of time‐varying simulation data that alleviates the cost associated with reloading and caching large data sets. | false | false | [
"Anna Tikhonova",
"Carlos D. Correa",
"Kwan-Liu Ma"
] | [] | [] | [] |
EuroVis | 2,010 | An Interactive Visual Analytics System for Bridge Management | 10.1111/j.1467-8659.2009.01708.x | Bridges deteriorate over their life cycles and require continuous maintenance to ensure their structural integrity, and in turn, the safety of the public. Maintaining bridges is a multi‐faceted operation that requires both domain knowledge and analytics techniques over large data sources. Although most existing bridge management systems (BMS) are very efficient at data storage, they are not as effective at providing analytical capabilities or as flexible at supporting different inspection technologies. In this paper, we present a visual analytics system that extends the capability of current BMSs. Based on a nation‐wide survey and our interviews with bridge managers, we designed our system to be customizable so that it can provide interactive exploration, information correlation, and domain‐oriented data analysis. When tested by bridge managers of the U.S. Department of Transportation, we validated that our system provides bridge managers with the necessary features for performing in‐depth analysis of bridges from a variety of perspectives that are in accordance to their typical workflow. | false | false | [
"Xiaoyu Wang 0001",
"Wenwen Dou",
"Shen-En Chen",
"William Ribarsky",
"Remco Chang"
] | [] | [] | [] |
EuroVis | 2,010 | Brushing Moments in Interactive Visual Analysis | 10.1111/j.1467-8659.2009.01697.x | We present a systematic study of opportunities for the interactive visual analysis of multi‐dimensional scientific data that is based on the integration of statistical aggregations along selected independent data dimensions in a framework of coordinated multiple views (with linking and brushing). Traditional and robust estimates of the four statistical moments (mean, variance, skewness, and kurtosis) as well as measures of outlyingness are integrated in an iterative visual analysis process. Brushing particular statistics, the analyst can investigate data characteristics such as trends and outliers. We present a categorization of beneficial combinations of attributes in 2D scatterplots: (a) kth vs. (k + 1)th statistical moment of a traditional or robust estimate, (b) traditional vs. robust version of the same moment, (c) two different robust estimates of the same moment. We propose selected view transformations to iteratively construct this multitude of informative views as well as to enhance the depiction of the statistical properties in scatterplots and quantile plots. In the framework, we interrelate the original distributional data and the aggregated statistics, which allows the analyst to work with both data representations simultaneously. We demonstrate our approach in the context of two visual analysis scenarios of multi‐run climate simulations. | false | false | [
"Johannes Kehrer",
"Peter Filzmoser",
"Helwig Hauser"
] | [] | [] | [] |
EuroVis | 2,010 | Coherent Culling and Shading for Large Molecular Dynamics Visualization | 10.1111/j.1467-8659.2009.01698.x | Molecular dynamics simulations are a principal tool for studying molecular systems. Such simulations are used to investigate molecular structure, dynamics, and thermodynamical properties, as well as a replacement for, or complement to, costly and dangerous experiments. With the increasing availability of computational power the resulting data sets are becoming increasingly larger, and benchmarks indicate that the interactive visualization on desktop computers poses a challenge when rendering substantially more than millions of glyphs. Trading visual quality for rendering performance is a common approach when interactivity has to be guaranteed. In this paper we address both problems and present a method for high‐quality visualization of massive molecular dynamics data sets. We employ several optimization strategies on different levels of granularity, such as data quantization, data caching in video memory, and a two‐level occlusion culling strategy: coarse culling via hardware occlusion queries and a vertex‐level culling using maximum depth mipmaps. To ensure optimal image quality we employ GPU raycasting and deferred shading with smooth normal vector generation. We demonstrate that our method allows us to interactively render data sets containing tens of millions of high‐quality glyphs. | false | false | [
"Sebastian Grottel",
"Guido Reina",
"Carsten Dachsbacher",
"Thomas Ertl"
] | [] | [] | [] |
EuroVis | 2,010 | DTI in Context: Illustrating Brain Fiber Tracts In Situ | 10.1111/j.1467-8659.2009.01692.x | We present an interactive illustrative visualization method inspired by traditional pen‐and‐ink illustration styles. Specifically, we explore how to provide context around DTI fiber tracts in the form of surfaces of the brain, the skull, or other objects such as tumors. These contextual surfaces are derived from either segmentation data or generated using interactive iso‐surface extraction and are rendered with a flexible, slice‐based hatching technique, controlled with ambient occlusion. This technique allows us to produce a consistent and frame‐coherent appearance with precise control over the lines. In addition, we provide context through cutting planes onto which we render gray matter with stippling. Together, our methods not only facilitate the interactive exploration and illustration of brain fibers within their anatomical context but also allow us to produce high‐quality images for print reproduction. We provide evidence for the success of our approach with an informal evaluation with domain experts. | false | false | [
"Pjotr Svetachov",
"Maarten H. Everts",
"Tobias Isenberg 0001"
] | [] | [] | [] |
EuroVis | 2,010 | Dynamic Multi-View Exploration of Shape Spaces | 10.1111/j.1467-8659.2009.01668.x | Statistical shape modeling is a widely used technique for the representation and analysis of the shapes and shape variations present in a population. A statistical shape model models the distribution in a high dimensional shape space, where each shape is represented by a single point.We present a design study on the intuitive exploration and visualization of shape spaces and shape models. Our approach focuses on the dual‐space nature of these spaces. The high‐dimensional shape space represents the population, whereas object space represents the shape of the 3D object associated with a point in shape space.A 3D object view provides local details for a single shape. The high dimensional points in shape space are visualized using a 2D scatter plot projection, the axes of which can be manipulated interactively. This results in a dynamic scatter plot, with the further extension that each point is visualized as a small version of the object shape that it represents. We further enhance the population‐object duality with a new type of view aimed at shape comparison. This new “shape evolution view” visualizes shape variability along a single trajectory in shape space, and serves as a link between the two spaces described above.Our three‐view exploration concept strongly emphasizes linked interaction between all spaces. Moving the cursor over the scatter plot or evolution views, shapes are dynamically interpolated and shown in the object view. Conversely, camera manipulation in the object view affects the object visualizations in the other views. We present a GPU‐accelerated implementation, and show the effectiveness of the three‐view approach using a number of real‐world cases. In these, we demonstrate how this multi‐view approach can be used to visually explore important aspects of a statistical shape model, including specificity, compactness and reconstruction error. | false | false | [
"Stef Busking",
"Charl P. Botha",
"Frits H. Post"
] | [] | [] | [] |
EuroVis | 2,010 | Effective Techniques to Visualize Filament-Surface Relationships | 10.1111/j.1467-8659.2009.01703.x | Combined visualizations of filamentous structures and surrounding volumetric objects are common in biological and medical applications. Often, the structures' spatial relationships remain unclear to the viewer. In this paper, we discuss and evaluate techniques to emphasize spatial relationships. We concentrate on the visualization of transparent objects and intersecting lines. Among various techniques, participants of an exploratory user study preferred coloring of lines, marking of line‐surface intersections by glyphs, and the combination of both. These techniques were additionally evaluated in a confirmatory study in which participants were asked to judge whether a filament runs through a transparent structure. We found that the evaluated techniques significantly improve the participants' performance in terms of the number of correct responses and response time. The best performance was found for the combination of line coloring and intersection glyph display. | false | false | [
"Anja Kuß",
"M. Gensel",
"Björn Meyer",
"Vincent J. Dercksen",
"Steffen Prohaska"
] | [] | [] | [] |
EuroVis | 2,010 | Estimation and Modeling of Actual Numerical Errors in Volume Rendering | 10.1111/j.1467-8659.2009.01685.x | In this paper we study the comprehensive effects on volume rendered images due to numerical errors caused by the use of finite precision for data representation and processing. To estimate actual error behavior we conduct a thorough study using a volume renderer implemented with arbitrary floating‐point precision. Based on the experimental data we then model the impact of floating‐point pipeline precision, sampling frequency and fixed‐point input data quantization on the fidelity of rendered images. We introduce three models, an average model, which does not adapt to different data nor varying transfer functions, as well as two adaptive models that take the intricacies of a new data set and transfer function into account by adapting themselves given a few different images rendered. We also test and validate our models based on new data that was not used during our model building. | false | false | [
"Joel Kronander",
"Jonas Unger",
"Torsten Möller",
"Anders Ynnerman"
] | [] | [] | [] |
EuroVis | 2,010 | Evaluation of Cluster Identification Performance for Different PCP Variants | 10.1111/j.1467-8659.2009.01666.x | Parallel coordinate plots (PCPs) are a well‐known visualization technique for viewing multivariate data. In the past, various visual modifications to PCPs have been proposed to facilitate tasks such as correlation and cluster identification, to reduce visual clutter, and to increase their information throughput. Most modifications pertain to the use of color and opacity, smooth curves, or the use of animation. Although many of these seem valid improvements, only few user studies have been performed to investigate this, especially with respect to cluster identification. We performed a user study to evaluate cluster identification performance – with respect to response time and correctness – of nine PCP variations, including standard PCPs. To generate the variations, we focused on covering existing techniques as well as possible while keeping testing feasible. This was done by adapting and merging techniques, which led to the following novel variations. The first is an effective way of embedding scatter plots into PCPs. The second is a technique for highlighting fuzzy clusters based on neighborhood density. The third is a spline‐based drawing technique to reduce ambiguity. The last is a pair of animation schemes for PCP rotation. We present an overview of the tested PCP variations and the results of our study. The most important result is that a fair number of the seemingly valid improvements, with the exception of scatter plots embedded into PCPs, do not result in significant performance gains. | false | false | [
"Danny Holten",
"Jarke J. van Wijk"
] | [] | [] | [] |
EuroVis | 2,010 | GraphDice: A System for Exploring Multivariate Social Networks | 10.1111/j.1467-8659.2009.01687.x | Social networks collected by historians or sociologists typically have a large number of actors and edge attributes. Applying social network analysis (SNA) algorithms to these networks produces additional attributes such as degree, centrality, and clustering coefficients. Understanding the effects of this plethora of attributes is one of the main challenges of multivariate SNA. We present the design of GraphDice, a multivariate network visualization system for exploring the attribute space of edges and actors. GraphDice builds upon the ScatterDice system for its main multidimensional navigation paradigm, and extends it with novel mechanisms to support network exploration in general and SNA tasks in particular. Novel mechanisms include visualization of attributes of interval type and projection of numerical edge attributes to node attributes. We show how these extensions to the original ScatterDice system allow to support complex visual analysis tasks on networks with hundreds of actors and up to 30 attributes, while providing a simple and consistent interface for interacting with network data. | false | false | [
"Anastasia Bezerianos",
"Fanny Chevalier",
"Pierre Dragicevic",
"Niklas Elmqvist",
"Jean-Daniel Fekete"
] | [] | [] | [] |
EuroVis | 2,010 | Hardware-Assisted Projected Tetrahedra | 10.1111/j.1467-8659.2009.01673.x | We present a flexible and highly efficient hardware‐assisted volume renderer grounded on the original Projected Tetrahedra (PT) algorithm. Unlike recent similar approaches, our method is exclusively based on the rasterization of simple geometric primitives and takes full advantage of graphics hardware. Both vertex and geometry shaders are used to compute the tetrahedral projection, while the volume ray integral is evaluated in a fragment shader; hence, volume rendering is performed entirely on the GPU within a single pass through the pipeline. We apply a CUDA‐based visibility ordering achieving rendering and sorting performance of over 6 M Tet/s for unstructured datasets. Furthermore, as each tetrahedron is processed independently, we employ a data‐parallel solution which is neither bound by GPU memory size nor does it rely on auxiliary volume information. In addition, iso‐surfaces can be readily extracted during the rendering process, and time‐varying data are handled without extra burden. | false | false | [
"André Maximo",
"Ricardo Marroquim",
"Ricardo C. Farias"
] | [] | [] | [] |
EuroVis | 2,010 | HyperMoVal: Interactive Visual Validation of Regression Models for Real-Time Simulation | 10.1111/j.1467-8659.2009.01684.x | During the development of car engines, regression models that are based on machine learning techniques are increasingly important for tasks which require a prediction of results in real‐time. While the validation of a model is a key part of its identification process, existing computation‐ or visualization‐based techniques do not adequately support all aspects of model validation. The main contribution of this paper is an interactive approach called HyperMoVal that is designed to support multiple tasks related to model validation: 1) comparing known and predicted results, 2) analyzing regions with a bad fit, 3) assessing the physical plausibility of models also outside regions covered by validation data, and 4) comparing multiple models. The key idea is to visually relate one or more n‐dimensional scalar functions to known validation data within a combined visualization. HyperMoVal lays out multiple 2D and 3D sub‐projections of the n‐dimensional function space around a focal point. We describe how linking HyperMoVal to other views further extends the possibilities for model validation. Based on this integration, we discuss steps towards supporting the entire workflow of identifying regression models. An evaluation illustrates a typical workflow in the application context of car‐engine design and reports general feedback of domain experts and users of our approach. These results indicate that our approach significantly accelerates the identification of regression models and increases the confidence in the overall engineering process. | false | false | [
"Harald Piringer",
"Wolfgang Berger",
"J. Krasser"
] | [] | [] | [] |
EuroVis | 2,010 | Illustrative White Matter Fiber Bundles | 10.1111/j.1467-8659.2009.01688.x | Diffusion Tensor Imaging (DTI) has made feasible the visualization of the fibrous structure of the brain white matter. In the last decades, several fiber‐tracking methods have been developed to reconstruct the fiber tracts from DTI data. Usually these fiber tracts are shown individually based on some selection criteria like region of interest. However, if the white matter as a whole is being visualized clutter is generated by directly rendering the individual fiber tracts. Often users are actually interested in fiber bundles, anatomically meaningful entities that abstract from the fibers they contain. Several clustering techniques have been developed that try to group the fiber tracts in fiber bundles. However, even if clustering succeeds, the complex nature of white matter still makes it difficult to investigate. In this paper, we propose the use of illustration techniques to ease the exploration of white matter clusters. We create a technique to visualize an individual cluster as a whole. The amount of fibers visualized for the cluster is reduced to just a few hint lines, and silhouette and contours are used to improve the definition of the cluster borders. Multiple clusters can be easily visualized by a combination of the single cluster visualizations. Focus+context concepts are used to extend the multiple‐cluster renderings. Exploded views ease the exploration of the focus cluster while keeping the context clusters in an abstract form. Real‐time results are achieved by the GPU implementation of the presented techniques. | false | false | [
"Ron Otten",
"Anna Vilanova",
"Huub van de Wetering"
] | [] | [] | [] |
EuroVis | 2,010 | Image-Based Edge Bundles: Simplified Visualization of Large Graphs | 10.1111/j.1467-8659.2009.01680.x | We present a new approach aimed at understanding the structure of connections in edge‐bundling layouts. We combine the advantages of edge bundles with a bundle‐centric simplified visual representation of a graph's structure. For this, we first compute a hierarchical edge clustering of a given graph layout which groups similar edges together. Next, we render clusters at a user‐selected level of detail using a new image‐based technique that combines distance‐based splatting and shape skeletonization. The overall result displays a given graph as a small set of overlapping shaded edge bundles. Luminance, saturation, hue, and shading encode edge density, edge types, and edge similarity. Finally, we add brushing and a new type of semantic lens to help navigation where local structures overlap. We illustrate the proposed method on several real‐world graph datasets. | false | false | [
"Alexandru C. Telea",
"Ozan Ersoy"
] | [] | [] | [] |
EuroVis | 2,010 | Isosurface Similarity Maps | 10.1111/j.1467-8659.2009.01689.x | In this paper, we introduce the concept of isosurface similarity maps for the visualization of volume data. Iso‐surface similarity maps present structural information of a volume data set by depicting similarities between individual isosurfaces quantified by a robust information‐theoretic measure. Unlike conventional histograms, they are not based on the frequency of isovalues and/or derivatives and therefore provide complementary information. We demonstrate that this new representation can be used to guide transfer function design and visualization parameter specification. Furthermore, we use isosurface similarity to develop an automatic parameter‐free method for identifying representative isovalues. Using real‐world data sets, we show that isosurface similarity maps can be a useful addition to conventional classification techniques. | false | false | [
"Stefan Bruckner",
"Torsten Möller"
] | [
"BP"
] | [] | [] |
EuroVis | 2,010 | Matrix Trees | 10.1111/j.1467-8659.2009.01709.x | We propose a new data representation for octrees and kd‐trees that improves upon memory size and algorithm speed of existing techniques. While pointerless approaches exploit the regular structure of the tree to facilitate efficient data access, their memory footprint becomes prohibitively large as the height of the tree increases. Pointerbased trees require memory consumption proportional to the number of tree nodes, thus exploiting the typical sparsity of large trees. Yet, their traversal is slowed by the need to follow explicit pointers across the different levels. Our solution is a pointerless approach that represents each tree level with its own matrix, as opposed to traditional pointerless trees that use only a single vector. This novel data organization allows us to fully exploit the tree's regular structure and improve the performance of tree operations. By using a sparse matrix data structure we obtain a representation that is suited for sparse and dense trees alike. In particular, it uses less total memory than pointer‐based trees even when the data set is extremely sparse. We show how our approach is easily implemented on the GPU and illustrate its performance in typical visualization scenarios. | false | false | [
"Nathan Andrysco",
"Xavier Tricoche"
] | [] | [] | [] |
EuroVis | 2,010 | Multi-layer Depth Peeling by Single-Pass Rasterisation for Faster Isosurface Raytracing on GPUs | 10.1111/j.1467-8659.2009.01674.x | Empty‐space skipping is an essential acceleration technique for volume rendering. Image‐order empty‐space skipping is not well suited to GPU implementation, since it must perform checks on, essentially, a per‐sample basis, as in kd‐tree traversal, which can lead to a great deal of divergent branching at runtime, which is very expensive in a modern GPU pipeline. In contrast, object‐order empty‐space skipping is extremely fast on a GPU and has negligible overheads compared with approaches without empty‐space skipping, since it employs the hardware unit for rasterisation. However, previous object‐order algorithms have been able to skip only exterior empty space and not the interior empty space that lies inside or between volume objects.In this paper, we address these issues by proposing a multi‐layer depth‐peeling approach that can obtain all of the depth layers of the tight‐fitting bounding geometry of the isosurface by a single rasterising pass. The maximum count of layers peeled by our approach can be up to thousands, while maintaining 32‐bit float‐point accuracy, which was not possible previously. By raytracing only the valid ray segments between each consecutive pair of depth layers, we can skip both the interior and exterior empty space efficiently.In comparisons with 3 state‐of‐the‐art GPU isosurface rendering algorithms, this technique achieved much faster rendering across a variety of data sets. | false | false | [
"Baoquan Liu",
"Gordon Clapworthy",
"Feng Dong 0005"
] | [] | [] | [] |
EuroVis | 2,010 | Non-iterative Second-order Approximation of Signed Distance Functions for Any Isosurface Representation | 10.1111/j.1467-8659.2009.01699.x | Signed distance functions (SDF) to explicit or implicit surface representations are intensively used in various computer graphics and visualization algorithms. Among others, they are applied to optimize collision detection, are used to reconstruct data fields or surfaces, and, in particular, are an obligatory ingredient for most level set methods. Level set methods are common in scientific visualization to extract surfaces from scalar or vector fields. Usual approaches for the construction of an SDF to a surface are either based on iterative solutions of a special partial differential equation or on marching algorithms involving a polygonization of the surface. We propose a novel method for a non‐iterative approximation of an SDF and its derivatives in a vicinity of a manifold. We use a second‐order algebraic fitting scheme to ensure high accuracy of the approximation. The manifold is defined (explicitly or implicitly) as an isosurface of a given volumetric scalar field. The field may be given at a set of irregular and unstructured samples. Stability and reliability of the SDF generation is achieved by a proper scaling of weights for the Moving Least Squares approximation, accurate choice of neighbors, and appropriate handling of degenerate cases. We obtain the solution in an explicit form, such that no iterative solving is necessary, which makes our approach fast. | false | false | [
"Vladimir Molchanov",
"Paul Rosenthal",
"Lars Linsen"
] | [] | [] | [] |
EuroVis | 2,010 | Out-of-Core Simplification and Crack-Free LOD Volume Rendering for Irregular Grids | 10.1111/j.1467-8659.2009.01705.x | We propose a novel out‐of‐core simplification and level‐of‐detail (LOD) volume rendering algorithm for large irregular grids represented as tetrahedral meshes. One important feature of our algorithm is that it creates a space decomposition as required by I/O‐efficient simplification and volume rendering, and simplifies both the internal and boundary portions of the sub‐volumes progressively by edge collapses using the (extended) quadric error metric, while ensuring any selected LOD mesh to be crack‐free (i.e., any neighboring sub‐volumes in the LOD have consistent boundaries, and all the cells in the LOD do not have negative volumes), with all computations performed I/O‐ejficiently. This has been an elusive goal for out‐of‐core progressive meshes and LOD visualization, and our novel solution achieves this goal with a theoretical guarantee to be crack‐free for tetrahedral meshes. As for selecting a desirable LOD mesh for volume rendering, our technique supports selective refinement LODs (where different places can have different error bounds), in addition to the basic uniform LODs (where the error bound is the same in all places). The proposed scalar‐value range and view‐dependent selection queries for selective refinement are especially effective in producing images of the highest quality with a much faster rendering speed. The experiments demonstrate the efficacy of our new technique. | false | false | [
"Zhiyan Du",
"Yi-Jen Chiang"
] | [] | [] | [] |
EuroVis | 2,010 | Pathline: A Tool For Comparative Functional Genomics | 10.1111/j.1467-8659.2009.01710.x | Biologists pioneering the new field of comparative functional genomics attempt to infer the mechanisms of gene regulation by looking for similarities and differences of gene activity over time across multiple species. They use three kinds of data: functional data such as gene activity measurements, pathway data that represent a series of reactions within a cellular process, and phylogenetic relationship data that describe the relatedness of species. No existing visualization tool can visually encode the biologically interesting relationships between multiple pathways, multiple genes, and multiple species. We tackle the challenge of visualizing all aspects of this comparative functional genomics dataset with a new interactive tool called Pathline. In addition to the overall characterization of the problem and design of Pathline, our contributions include two new visual encoding techniques. One is a new method for linearizing metabolic pathways that provides appropriate topological information and supports the comparison of quantitative data along the pathway. The second is the curvemap view, a depiction of time series data for comparison of gene activity and metabolite levels across multiple species. Pathline was developed in close collaboration with a team of genomic scientists. We validate our approach with case studies of the biologists’ use of Pathline and report on how they use the tool to confirm existing findings and to discover new scientific insights. | false | false | [
"Miriah D. Meyer",
"Bang Wong",
"Mark P. Styczynski",
"Tamara Munzner",
"Hanspeter Pfister"
] | [] | [] | [] |
EuroVis | 2,010 | ProbExplorer: Uncertainty-guided Exploration and Editing of Probabilistic Medical Image Segmentation | 10.1111/j.1467-8659.2009.01691.x | In this paper, we develop an interactive analysis and visualization tool for probabilistic segmentation results in medical imaging. We provide a systematic approach to analyze, interact and highlight regions of segmentation uncertainty. We introduce a set of visual analysis widgets integrating different approaches to analyze multivariate probabilistic field data with direct volume rendering. We demonstrate the user's ability to identify suspicious regions (e.g. tumors) and correct the misclassification results using a novel uncertainty‐based segmentation editing technique. We evaluate our system and demonstrate its usefulness in the context of static and time‐varying medical imaging datasets. | false | false | [
"Ahmed Saad",
"Torsten Möller",
"Ghassan Hamarneh"
] | [] | [] | [] |
EuroVis | 2,010 | Real-Time Temporal-Coherent Color Contrast Enhancement for Dichromats | 10.1111/j.1467-8659.2009.01701.x | We present an automatic image‐recoloring technique for enhancing color contrast for dichromats whose computational cost varies linearly with the number of input pixels. Our approach can be efficiently implemented on GPUs, and we show that for typical image sizes it is up to two orders of magnitude faster than the current state‐of‐the‐art technique. Unlike previous approaches, ours preserve temporal coherence and, therefore, is suitable for video recoloring. We demonstrate the effectiveness of our technique by integrating it into a visualization system and showing, for the first time, real‐time high‐quality recolored visualizations for dichromats. | false | false | [
"Gustavo Mello Machado",
"Manuel M. Oliveira"
] | [] | [] | [] |
EuroVis | 2,010 | Reusable Visualizations and Animations for Surgery Planning | 10.1111/j.1467-8659.2009.01669.x | For surgical planning, the exploration of 3D visualizations and 2D slice views is essential. However, the generation of visualizations which support the specific treatment decisions is very tedious. Therefore, the reuse of once designed visualizations for similar cases can strongly accelerate the process of surgical planning. We present a new technique that enables the easy reuse of both medical visualization types: 3D scenes and 2D slice views. We introduce the keystates as a concept to describe the state of a visualization in a general manner. They can be easily applied to new datasets to create similar visualizations. Keystates can be shared between surgeons of one specialization to reproduce and document the planning process for collaborative work. Furthermore, animations can support the surgeon on individual exploration and are also useful in collaborative environments, where complex issues must be presented in a short time. Therefore, we provide a framework, where animations can be visually designed by surgeons during their exploration process without any programming or authoring skills. We discuss several transitions between different visualizations and present an application from clinical routine. | false | false | [
"Konrad Mühler",
"Bernhard Preim"
] | [] | [] | [] |
EuroVis | 2,010 | Scalable Multi-view Registration for Multi-Projector Displays on Vertically Extruded Surfaces | 10.1111/j.1467-8659.2009.01676.x | Recent work have shown that it is possible to register multiple projectors on non‐planar surfaces using a single uncalibrated camera instead of a calibrated stereo pair when dealing with a special class of non‐planar surfaces, vertically extruded surfaces. However, this requires the camera view to contain the entire display surface. This is often an impossible scenario for large displays, especially common in visualization, edutainment, training and simulation applications. In this paper we present a new method that can achieve an accurate geometric registration even when the field‐of‐view of the uncalibrated camera can cover only a part of the vertically extruded display at a time. We pan and tilt the camera from a single point and employ a multi‐view approach to register the projectors on the display. This allows the method to scale easily both in terms of camera resolution and display size. To the best of our knowledge, our method is the first to achieve a scalable multi‐view geometric registration of large vertically extruded displays with a single uncalibrated camera. This method can also handle a different situation of having multiple similarly oriented cameras in different locations, if the camera focal length is known. | false | false | [
"Behzad Sajadi",
"Aditi Majumder"
] | [] | [] | [] |
EuroVis | 2,010 | SmallWorlds: Visualizing Social Recommendations | 10.1111/j.1467-8659.2009.01679.x | We present SmallWorlds, a visual interactive graph‐based interface that allows users to specify, refine and build item‐preference profiles in a variety of domains. The interface facilitates expressions of taste through simple graph interactions and these preferences are used to compute personalized, fully transparent item recommendations for a target user. Predictions are based on a collaborative analysis of preference data from a user's direct peer group on a social network. We find that in addition to receiving transparent and accurate item recommendations, users also learn a wealth of information about the preferences of their peers through interaction with our visualization. Such information is not easily discoverable in traditional text based interfaces. A detailed analysis of our design choices for visual layout, interaction and prediction techniques is presented. Our evaluations discuss results from a user study in which SmallWorlds was deployed as an interactive recommender system on Facebook. | false | false | [
"Brynjar Gretarsson",
"John O'Donovan",
"Svetlin Bostandjiev",
"Christopher Hall 0001",
"Tobias Höllerer"
] | [] | [] | [] |
EuroVis | 2,010 | Space-in-Time and Time-in-Space Self-Organizing Maps for Exploring Spatiotemporal Patterns | 10.1111/j.1467-8659.2009.01664.x | Spatiotemporal data pose serious challenges to analysts in geographic and other domains. Owing to the complexity of the geospatial and temporal components, this kind of data cannot be analyzed by fully automatic methods but require the involvement of the human analyst's expertise. For a comprehensive analysis, the data need to be considered from two complementary perspectives: (1) as spatial distributions (situations) changing over time and (2) as profiles of local temporal variation distributed over space. In order to support the visual analysis of spatiotemporal data, we suggest a framework based on the “Self‐Organizing Map” (SOM) method combined with a set of interactive visual tools supporting both analytic perspectives. SOM can be considered as a combination of clustering and dimensionality reduction. In the first perspective, SOM is applied to the spatial situations at different time moments or intervals. In the other perspective, SOM is applied to the local temporal evolution profiles. The integrated visual analytics environment includes interactive coordinated displays enabling various transformations of spatiotemporal data and post‐processing of SOM results. The SOM matrix display offers an overview of the groupings of data objects and their two‐dimensional arrangement by similarity. This view is linked to a cartographic map display, a time series graph, and a periodic pattern view. The linkage of these views supports the analysis of SOM results in both the spatial and temporal contexts. The variable SOM grid coloring serves as an instrument for linking the SOM with the corresponding items in the other displays. The framework has been validated on a large dataset with real city traffic data, where expected spatiotemporal patterns have been successfully uncovered. We also describe the use of the framework for discovery of previously unknown patterns in 41‐years time series of 7 crime rate attributes in the states of the USA. | false | false | [
"Gennady L. Andrienko",
"Natalia V. Andrienko",
"Sebastian Bremm",
"Tobias Schreck",
"Tatiana von Landesberger",
"Peter Bak",
"Daniel A. Keim"
] | [] | [] | [] |
EuroVis | 2,010 | Streaming-Enabled Parallel Dataflow Architecture for Multicore Systems | 10.1111/j.1467-8659.2009.01704.x | We propose a new framework design for exploiting multi‐core architectures in the context of visualization dataflow systems. Recent hardware advancements have greatly increased the levels of parallelism available with all indications showing this trend will continue in the future. Existing visualization dataflow systems have attempted to take advantage of these new resources, though they still have a number of limitations when deployed on shared memory multi‐core architectures. Ideally, visualization systems should be built on top of a parallel dataflow scheme that can optimally utilize CPUs and assign resources adaptively to pipeline elements. We propose the design of a flexible dataflow architecture aimed at addressing many of the shortcomings of existing systems including a unified execution model for both demand‐driven and event‐driven models; a resource scheduler that can automatically make decisions on how to allocate computing resources; and support for more general streaming data structures which include unstructured elements. We have implemented our system on top of VTK with backward compatibility. In this paper, we provide evidence of performance improvements on a number of applications. | false | false | [
"Huy T. Vo",
"Daniel K. Osmari",
"Brian Summa",
"João Luiz Dihl Comba",
"Valerio Pascucci",
"Cláudio T. Silva"
] | [] | [] | [] |
EuroVis | 2,010 | Supporting Exploratory Analysis with the Select & Slice Table | 10.1111/j.1467-8659.2009.01696.x | In interactive visualization, selection techniques such as dynamic queries and brushing are used to specify and extract items of interest. In other words, users define areas of interest in data space that often have a clear semantic meaning. We call such areas Semantic Zones, and argue that support for their manipulation and reasoning with them is highly useful during exploratory analysis. An important use case is the use of these zones across different subsets of the data, for instance to study the population of semantic zones over time. To support this, we present the Select & Slice Table. Semantic zones are arranged along one axis of the table, and data subsets are arranged along the other axis of the table. Each cell contains a set of items of interest from a data subset that matches the selection specifications of a zone. Items in cells can be visualized in various ways, as a count, as an aggregation of a measure, or as a separate visualization, such that the table gives an overview of the relationship between zones and data subsets. Furthermore, users can reuse zones, combine zones, and compare and trace items of interest across different semantic zones and data subsets. We present two case studies to illustrate the support offered by the Select & Slice table during exploratory analysis of multivariate data. | false | false | [
"Yedendra Babu Shrinivasan",
"Jarke J. van Wijk"
] | [] | [] | [] |
EuroVis | 2,010 | The Perception of Correlation in Scatterplots | 10.1111/j.1467-8659.2009.01694.x | We present a rigorous way to evaluate the visual perception of correlation in scatterplots, based on classical psychophysical methods originally developed for simple properties such as brightness. Although scatterplots are graphically complex, the quantity they convey is relatively simple. As such, it may be possible to assess the perception of correlation in a similar way.Scatterplots were each of 5.0° extent, containing 100 points with a bivariate normal distribution. Means were 0.5 of the range of the points, and standard deviations 0.2 of this range. Precision was determined via an adaptive algorithm to find the just noticeable differences (jnds) in correlation, i.e., the difference between two side‐by‐side scatterplots that could be discriminated 75% of the time. Accuracy was measured by direct estimation, using reference scatterplots with fixed upper and lower values, with a test scatterplot adjusted so that its correlation appeared to be halfway between these. This process was recursively applied to yield several further estimates.Results of the discrimination tests show jnd(r) = k (1/b – r), where r is the Pearson correlation, and parameters 0 < k, b < 1. Integration yields a subjective estimate of correlation g(r) = ln(1 – br) / ln(1 – b). The values of b found via discrimination closely match those found via direct estimation. As such, it appears that the perception of correlation in a scatterplot is completely described by two related performance curves, specified by two easily‐measured parameters. | false | false | [
"Ronald A. Rensink",
"Gideon Baldridge"
] | [] | [] | [] |
EuroVis | 2,010 | The Readability of Path-Preserving Clusterings of Graphs | 10.1111/j.1467-8659.2009.01683.x | Graph visualization systems often exploit opaque metanodes to reduce visual clutter and improve the readability of large graphs. This filtering can be done in a path‐preserving way based on attribute values associated with the nodes of the graph. Despite extensive use of these representations, as far as we know, no formal experimentation exists to evaluate if they improve the readability of graphs.In this paper, we present the results of a user study that formally evaluates how such representations affect the readability of graphs. We also explore the effect of graph size and connectivity in terms of this primary research question. Overall, for our tasks, we did not find a significant difference when this clustering is used. However, if the graph is highly connected, these clusterings can improve performance. Also, if the graph is large enough and can be simplified into a few metanodes, benefits in performance on global tasks are realized. Under these same conditions, however, performance of local attribute tasks may be reduced. | false | false | [
"Daniel Archambault",
"Helen C. Purchase",
"Bruno Pinaud"
] | [] | [] | [] |
EuroVis | 2,010 | Topographic Map Visualization from Adaptively Compressed Textures | 10.1111/j.1467-8659.2009.01682.x | Raster‐based topographic maps are commonly used in geoinformation systems to overlay geographic entities on top of digital terrain models. Using compressed texture formats for encoding topographic maps allows reducing latency times while visualizing large geographic datasets. Topographic maps encompass high‐frequency content with large uniform regions, making current compressed texture formats inappropriate for encoding them. In this paper we present a method for locally‐adaptive compression of topographic maps. Key elements include a Hilbert scan to maximize spatial coherence, efficient encoding of homogeneous image regions through arbitrarily‐sized texel runs, a cumulative run‐length encoding supporting fast random‐access, and a compression algorithm supporting lossless and lossy compression. Our scheme can be easily implemented on current programmable graphics hardware allowing real‐time GPU decompression and rendering of bilinear‐filtered topographic maps. | false | false | [
"Carlos Andújar"
] | [] | [] | [] |
EuroVis | 2,010 | Topological Landscape Ensembles for Visualization of Scalar-Valued Functions | 10.1111/j.1467-8659.2009.01706.x | Visual representation techniques enable perception and exploration of scientific data. Following the topological landscapes metaphor of Weber et al., we provide a new algorithm for visualizing scalar functions defined on simply connected domains of arbitrary dimension. For a potentially high dimensional scalar field, our algorithm produces a collection of, in some sense complete, two‐dimensional terrain models whose contour trees and corresponding topological persistences are identical to those of the input scalar field. The algorithm exactly preserves the volume of each region corresponding to an arc in the contour tree. We also introduce an efficiently computable metric on terrain models we generate. Based on this metric, we develop a tool that can help the users to explore the space of possible terrain models. | false | false | [
"William Harvey 0001",
"Yusu Wang 0001"
] | [
"BP"
] | [] | [] |
EuroVis | 2,010 | Topology Aware Stream Surfaces | 10.1111/j.1467-8659.2009.01672.x | We present an algorithm that allows stream surfaces to recognize and adapt to vector field topology. Standard stream surface algorithms either refine the surface uncontrolled near critical points which slows down the computation considerably and may lead to a poor surface approximation. Alternatively, the concerned region is omitted from the stream surface by severing it into two parts thus generating an incomplete stream surface. Our algorithm utilizes topological information to provide a fast, accurate, and complete triangulation of the stream surface near critical points. The required topological information is calculated in a preprocessing step. We compare our algorithm against the standard approach both visually and in performance. | false | false | [
"Dominic Schneider",
"Wieland Reich",
"Alexander Wiebel",
"Gerik Scheuermann"
] | [] | [] | [] |
EuroVis | 2,010 | Topology-based Smoothing of 2D Scalar Fields with C1-Continuity | 10.1111/j.1467-8659.2009.01702.x | Data sets coming from simulations or sampling of real‐world phenomena often contain noise that hinders their processing and analysis. Automatic filtering and denoising can be challenging: when the nature of the noise is unknown, it is difficult to distinguish between noise and actual data features; in addition, the filtering process itself may introduce “artificial” features into the data set that were not originally present. In this paper, we propose a smoothing method for 2D scalar fields that gives the user explicit control over the data features. We define features as critical points of the given scalar function, and the topological structure they induce (i.e., the Morse‐Smale complex). Feature significance is rated according to topological persistence. Our method allows filtering out spurious features that arise due to noise by means of topological simplification, providing the user with a simple interface that defines the significance threshold, coupled with immediate visual feedback of the remaining data features. In contrast to previous work, our smoothing method guarantees a C1‐continuous output scalar field with the exact specified features and topological structures. | false | false | [
"Tino Weinkauf",
"Yotam I. Gingold",
"Olga Sorkine"
] | [] | [] | [] |
EuroVis | 2,010 | Toward a Lagrangian Vector Field Topology | 10.1111/j.1467-8659.2009.01686.x | In this paper we present an extended critical point concept which allows us to apply vector field topology in the case of unsteady flow. We propose a measure for unsteadiness which describes the rate of change of the velocities in a fluid element over time. This measure allows us to select particles for which topological properties remain intact inside a finite spatio‐temporal neighborhood. One benefit of this approach is that the classification of critical points based on the eigenvalues of the Jacobian remains meaningful. In the steady case the proposed criterion reduces to the classical definition of critical points. As a first step we show that finding an optimal Galilean frame of reference can be obtained implicitly by analyzing the acceleration field. In a second step we show that this can be extended by switching to the Lagrangian frame of reference. This way the criterion can detect critical points moving along intricate trajectories. We analyze the behavior of the proposed criterion based on two analytical vector fields for which a correct solution is defined by their inherent symmetries and present results for numerical vector fields. | false | false | [
"Raphael Fuchs",
"Jan Kemmler",
"Benjamin Schindler",
"Jürgen Waser",
"Filip Sadlo",
"Helwig Hauser",
"Ronald Peikert"
] | [] | [] | [] |
EuroVis | 2,010 | Understanding Interactive Legends: a Comparative Evaluation with Standard Widgets | 10.1111/j.1467-8659.2009.01678.x | Interactive information visualization systems rely on widgets to allow users to interact with the data and modify the representation. We define interactive legends as a class of controls combining the visual representation of static legends and interaction mechanisms of widgets. As interactive legends start to appear in popular websites, we categorize their designs for common data types and evaluate their effectiveness compare to standard widgets. Results suggest that 1) interactive legends can lead to faster perception of the mapping between data values and visual encodings and 2) interaction time is affected differently depending on the data type. Additionally, our study indicates superiority both in terms of perception and interaction of ordinal controls over numerical ones. Numerical techniques are mostly used in today's systems. By providing solutions to allowing users to modify ranges interactively, we believe that interactive legends make it possible to increase the use of ordinal techniques for visual exploration. | false | false | [
"Nathalie Henry Riche",
"Bongshin Lee",
"Catherine Plaisant"
] | [] | [] | [] |
EuroVis | 2,010 | Video Visualization for Snooker Skill Training | 10.1111/j.1467-8659.2009.01670.x | We present a feasibility study on using video visualization to aid snooker skill training. By involving the coaches and players in the loop of intelligent reasoning, our approach addresses the difficulties of automated semantic reasoning, while benefiting from mature video processing techniques. This work was conducted in conjunction with a snooker club and a sports scientist. In particular, we utilized the principal design of the VideoPerpetuoGram (VPG) to convey spatiotemporal information to the viewers through static visualization, removing the burden of repeated video viewing. We extended the VPG design to accommodate the need for depicting multiple video streams and respective temporal attribute fields, including silhouette extrusion, spatial attributes, and non‐spatial attributes. Our results and evaluation have shown that video visualization can provide snooker coaching with visually quantifiable and comparable summary records, and is thus a cost‐effective means for assessing skill levels and monitoring progress objectively and consistently. | false | false | [
"Markus Höferlin",
"Edward Grundy",
"Rita Borgo",
"Daniel Weiskopf",
"Min Chen 0001",
"Iwan W. Griffiths",
"W. Griffiths"
] | [] | [] | [] |
EuroVis | 2,010 | Visual Analysis of Multi-Joint Kinematic Data | 10.1111/j.1467-8659.2009.01681.x | Kinematics is the analysis of motions without regarding forces or inertial effects, with the purpose of understanding joint behaviour. Kinematic data of linked joints, for example the upper extremity, i.e. the shoulder and arm joints, contains many related degrees of freedom that complicate numerical analysis. Visualisation techniques enhance the analysis process, thus improving the effectiveness of kinematic experiments.This paper describes a new visualisation system specifically designed for the analysis of multi‐joint kinematic data of the upper extremity. The challenge inherent in the data is that the upper extremity is comprised of five cooperating joints with a total of fifteen degrees of freedom. The range of motion may be affected by subtle deficiencies of individual joints that are difficult to pinpoint. To highlight these subtleties our approach combines interactive filtering and multiple visualisation techniques.Our system is further differentiated by the fact that it integrates simultaneous acquisition and visual analysis of biokinematic data. Also, to facilitate complex queries, we have designed a visual query interface with visualisation and interaction elements that are based on the domain‐specific anatomical representation of the data. The combination of these techniques form an effective approach specifically tailored for the investigation and comparison of large collections of kinematic data. This claim is supported by an evaluation experiment where the technique was used to inspect the kinematics of the left and right arm of a patient with a healed proximal humerus fracture, i.e. a healed shoulder fracture. | false | false | [
"Peter R. Krekel",
"Edward R. Valstar",
"Jurriaan H. De Groot",
"Frits H. Post",
"Rob G. H. H. Nelissen",
"Charl P. Botha"
] | [] | [] | [] |
EuroVis | 2,010 | Visual Support for Interactive Post-Interventional Assessment of Radiofrequency Ablation Therapy | 10.1111/j.1467-8659.2009.01665.x | Percutaneous radiofrequency (RF) ablation is a minimally invasive, image‐guided therapy for the treatment of liver tumors. The assessment of the ablation area (coagulation) is performed to verify the treatment success as an essential part of the therapy. Traditionally, pre‐ and post‐interventional CT images are used to visually compare the shape, size, and position of tumor and coagulation.In this work, we present a novel visualization as well as a navigation tool, the so‐called tumor map. The tumor map is a pseudo‐cylindrical mapping of the tumor surface onto a 2D image. It is used for a combined visualization of all ablation zones of the tumor to allow a reliable therapy assessment. Additionally, the tumor map serves as an interactive tool for intuitive navigation within the 3D volume rendering of the tumor vicinity as well as with familiar 2D viewers. | false | false | [
"Christian Rieder",
"Andreas Weihusen",
"Christian Schumann",
"Stephan Zidowitz",
"Heinz-Otto Peitgen"
] | [] | [] | [] |
EuroVis | 2,010 | Visualization and Analysis-Oriented Reconstruction of Material Interfaces | 10.1111/j.1467-8659.2009.01671.x | Reconstructing boundaries along material interfaces from volume fractions is a difficult problem, especially because the under‐resolved nature of the input data allows for many correct interpretations. Worse, algorithms widely accepted as appropriate for simulation are inappropriate for visualization. In this paper, we describe a new algorithm that is specifically intended for reconstructing material interfaces for visualization and analysis requirements. The algorithm performs well with respect to memory footprint and execution time, has desirable properties in various accuracy metrics, and also produces smooth surfaces with few artifacts, even when faced with more than two materials per cell. | false | false | [
"Jeremy S. Meredith",
"Hank Childs"
] | [] | [] | [] |
EuroVis | 2,010 | Visualizing Summary Statistics and Uncertainty | 10.1111/j.1467-8659.2009.01677.x | The graphical depiction of uncertainty information is emerging as a problem of great importance. Scientific data sets are not considered complete without indications of error, accuracy, or levels of confidence. The visual portrayal of this information is a challenging task. This work takes inspiration from graphical data analysis to create visual representations that show not only the data value, but also important characteristics of the data including uncertainty. The canonical box plot is reexamined and a new hybrid summary plot is presented that incorporates a collection of descriptive statistics to highlight salient features of the data. Additionally, we present an extension of the summary plot to two dimensional distributions. Finally, a use‐case of these new plots is presented, demonstrating their ability to present high‐level overviews as well as detailed insight into the salient features of the underlying data distribution. | false | false | [
"Kristin Potter",
"Joe Kniss",
"Richard F. Riesenfeld",
"Chris R. Johnson 0001"
] | [] | [] | [] |
EuroVis | 2,010 | Winding Roads: Routing edges into bundles | 10.1111/j.1467-8659.2009.01700.x | Visualizing graphs containing many nodes and edges efficiently is quite challenging. Drawings of such graphs generally suffer from visual clutter induced by the large amount of edges and their crossings. Consequently it is difficult to read the relationships between nodes and the high‐level edge patterns that may exist in standard node‐link diagram representations. Edge bundling techniques have been proposed to help solve this issue, which rely on high quality edge rerouting. In this paper, we introduce an intuitive edge bundling technique which efficiently reduces edge clutter in graphs drawings. Our method is based on the use of a grid built using the original graph to compute the edge rerouting. In comparison with previously proposed edge bundling methods, our technique improves both the level of clutter reduction and the computation performance. The second contribution of this paper is a GPU‐based rendering method which helps users perceive bundles densities while preserving edge color. | false | false | [
"Antoine Lambert",
"Romain Bourqui",
"David Auber"
] | [] | [] | [] |
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