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 |
|---|---|---|---|---|---|---|---|---|---|---|
InfoVis | 2,012 | Perception of Visual Variables on Tiled Wall-Sized Displays for Information Visualization Applications | 10.1109/TVCG.2012.251 | We present the results of two user studies on the perception of visual variables on tiled high-resolution wall-sized displays. We contribute an understanding of, and indicators predicting how, large variations in viewing distances and viewing angles affect the accurate perception of angles, areas, and lengths. Our work, thus, helps visualization researchers with design considerations on how to create effective visualizations for these spaces. The first study showed that perception accuracy was impacted most when viewers were close to the wall but differently for each variable (Angle, Area, Length). Our second study examined the effect of perception when participants could move freely compared to when they had a static viewpoint. We found that a far but static viewpoint was as accurate but less time consuming than one that included free motion. Based on our findings, we recommend encouraging viewers to stand further back from the display when conducting perception estimation tasks. If tasks need to be conducted close to the wall display, important information should be placed directly in front of the viewer or above, and viewers should be provided with an estimation of the distortion effects predicted by our work-or encouraged to physically navigate the wall in specific ways to reduce judgement error. | false | false | [
"Anastasia Bezerianos",
"Petra Isenberg"
] | [] | [] | [] |
InfoVis | 2,012 | PivotPaths: Strolling through Faceted Information Spaces | 10.1109/TVCG.2012.252 | We present PivotPaths, an interactive visualization for exploring faceted information resources. During both work and leisure, we increasingly interact with information spaces that contain multiple facets and relations, such as authors, keywords, and citations of academic publications, or actors and genres of movies. To navigate these interlinked resources today, one typically selects items from facet lists resulting in abrupt changes from one subset of data to another. While filtering is useful to retrieve results matching specific criteria, it can be difficult to see how facets and items relate and to comprehend the effect of filter operations. In contrast, the PivotPaths interface exposes faceted relations as visual paths in arrangements that invite the viewer to `take a stroll' through an information space. PivotPaths supports pivot operations as lightweight interaction techniques that trigger gradual transitions between views. We designed the interface to allow for casual traversal of large collections in an aesthetically pleasing manner that encourages exploration and serendipitous discoveries. This paper shares the findings from our iterative design-and-evaluation process that included semi-structured interviews and a two-week deployment of PivotPaths applied to a large database of academic publications. | false | false | [
"Marian Dörk",
"Nathalie Henry Riche",
"Gonzalo A. Ramos",
"Susan T. Dumais"
] | [] | [] | [] |
InfoVis | 2,012 | RankExplorer: Visualization of Ranking Changes in Large Time Series Data | 10.1109/TVCG.2012.253 | For many applications involving time series data, people are often interested in the changes of item values over time as well as their ranking changes. For example, people search many words via search engines like Google and Bing every day. Analysts are interested in both the absolute searching number for each word as well as their relative rankings. Both sets of statistics may change over time. For very large time series data with thousands of items, how to visually present ranking changes is an interesting challenge. In this paper, we propose RankExplorer, a novel visualization method based on ThemeRiver to reveal the ranking changes. Our method consists of four major components: 1) a segmentation method which partitions a large set of time series curves into a manageable number of ranking categories; 2) an extended ThemeRiver view with embedded color bars and changing glyphs to show the evolution of aggregation values related to each ranking category over time as well as the content changes in each ranking category; 3) a trend curve to show the degree of ranking changes over time; 4) rich user interactions to support interactive exploration of ranking changes. We have applied our method to some real time series data and the case studies demonstrate that our method can reveal the underlying patterns related to ranking changes which might otherwise be obscured in traditional visualizations. | false | false | [
"Conglei Shi",
"Weiwei Cui",
"Shixia Liu",
"Panpan Xu",
"Wei Chen 0001",
"Huamin Qu"
] | [] | [] | [] |
InfoVis | 2,012 | RelEx: Visualization for Actively Changing Overlay Network Specifications | 10.1109/TVCG.2012.255 | We present a network visualization design study focused on supporting automotive engineers who need to specify and optimize traffic patterns for in-car communication networks. The task and data abstractions that we derived support actively making changes to an overlay network, where logical communication specifications must be mapped to an underlying physical network. These abstractions are very different from the dominant use case in visual network analysis, namely identifying clusters and central nodes, that stems from the domain of social network analysis. Our visualization tool RelEx was created and iteratively refined through a full user-centered design process that included a full problem characterization phase before tool design began, paper prototyping, iterative refinement in close collaboration with expert users for formative evaluation, deployment in the field with real analysts using their own data, usability testing with non-expert users, and summative evaluation at the end of the deployment. In the summative post-deployment study, which entailed domain experts using the tool over several weeks in their daily practice, we documented many examples where the use of RelEx simplified or sped up their work compared to previous practices. | false | false | [
"Michael Sedlmair",
"Annika Frank",
"Tamara Munzner",
"Andreas Butz"
] | [] | [] | [] |
InfoVis | 2,012 | Representative Factor Generation for the Interactive Visual Analysis of High-Dimensional Data | 10.1109/TVCG.2012.256 | Datasets with a large number of dimensions per data item (hundreds or more) are challenging both for computational and visual analysis. Moreover, these dimensions have different characteristics and relations that result in sub-groups and/or hierarchies over the set of dimensions. Such structures lead to heterogeneity within the dimensions. Although the consideration of these structures is crucial for the analysis, most of the available analysis methods discard the heterogeneous relations among the dimensions. In this paper, we introduce the construction and utilization of representative factors for the interactive visual analysis of structures in high-dimensional datasets. First, we present a selection of methods to investigate the sub-groups in the dimension set and associate representative factors with those groups of dimensions. Second, we introduce how these factors are included in the interactive visual analysis cycle together with the original dimensions. We then provide the steps of an analytical procedure that iteratively analyzes the datasets through the use of representative factors. We discuss how our methods improve the reliability and interpretability of the analysis process by enabling more informed selections of computational tools. Finally, we demonstrate our techniques on the analysis of brain imaging study results that are performed over a large group of subjects. | false | false | [
"Cagatay Turkay",
"Arvid Lundervold",
"Astri J. Lundervold",
"Helwig Hauser"
] | [] | [] | [] |
InfoVis | 2,012 | Sketchy Rendering for Information Visualization | 10.1109/TVCG.2012.262 | We present and evaluate a framework for constructing sketchy style information visualizations that mimic data graphics drawn by hand. We provide an alternative renderer for the Processing graphics environment that redefines core drawing primitives including line, polygon and ellipse rendering. These primitives allow higher-level graphical features such as bar charts, line charts, treemaps and node-link diagrams to be drawn in a sketchy style with a specified degree of sketchiness. The framework is designed to be easily integrated into existing visualization implementations with minimal programming modification or design effort. We show examples of use for statistical graphics, conveying spatial imprecision and for enhancing aesthetic and narrative qualities of visualization. We evaluate user perception of sketchiness of areal features through a series of stimulus-response tests in order to assess users' ability to place sketchiness on a ratio scale, and to estimate area. Results suggest relative area judgment is compromised by sketchy rendering and that its influence is dependent on the shape being rendered. They show that degree of sketchiness may be judged on an ordinal scale but that its judgement varies strongly between individuals. We evaluate higher-level impacts of sketchiness through user testing of scenarios that encourage user engagement with data visualization and willingness to critique visualization design. Results suggest that where a visualization is clearly sketchy, engagement may be increased and that attitudes to participating in visualization annotation are more positive. The results of our work have implications for effective information visualization design that go beyond the traditional role of sketching as a tool for prototyping or its use for an indication of general uncertainty. | false | false | [
"Jo Wood",
"Petra Isenberg",
"Tobias Isenberg 0001",
"Jason Dykes",
"Nadia Boukhelifa",
"Aidan Slingsby"
] | [] | [] | [] |
InfoVis | 2,012 | SnapShot: Visualization to Propel Ice Hockey Analytics | 10.1109/TVCG.2012.263 | Sports analysts live in a world of dynamic games flattened into tables of numbers, divorced from the rinks, pitches, and courts where they were generated. Currently, these professional analysts use R, Stata, SAS, and other statistical software packages for uncovering insights from game data. Quantitative sports consultants seek a competitive advantage both for their clients and for themselves as analytics becomes increasingly valued by teams, clubs, and squads. In order for the information visualization community to support the members of this blossoming industry, it must recognize where and how visualization can enhance the existing analytical workflow. In this paper, we identify three primary stages of today's sports analyst's routine where visualization can be beneficially integrated: 1) exploring a dataspace; 2) sharing hypotheses with internal colleagues; and 3) communicating findings to stakeholders.Working closely with professional ice hockey analysts, we designed and built SnapShot, a system to integrate visualization into the hockey intelligence gathering process. SnapShot employs a variety of information visualization techniques to display shot data, yet given the importance of a specific hockey statistic, shot length, we introduce a technique, the radial heat map. Through a user study, we received encouraging feedback from several professional analysts, both independent consultants and professional team personnel. | false | false | [
"Hannah Pileggi",
"Charles D. Stolper",
"J. Michael Boyle",
"John T. Stasko"
] | [] | [] | [] |
InfoVis | 2,012 | Spatial Text Visualization Using Automatic Typographic Maps | 10.1109/TVCG.2012.264 | We present a method for automatically building typographic maps that merge text and spatial data into a visual representation where text alone forms the graphical features. We further show how to use this approach to visualize spatial data such as traffic density, crime rate, or demographic data. The technique accepts a vector representation of a geographic map and spatializes the textual labels in the space onto polylines and polygons based on user-defined visual attributes and constraints. Our sample implementation runs as a Web service, spatializing shape files from the OpenStreetMap project into typographic maps for any region. | false | false | [
"Shehzad Afzal",
"Ross Maciejewski",
"Yun Jang",
"Niklas Elmqvist",
"David S. Ebert"
] | [] | [] | [] |
InfoVis | 2,012 | Stacking-Based Visualization of Trajectory Attribute Data | 10.1109/TVCG.2012.265 | Visualizing trajectory attribute data is challenging because it involves showing the trajectories in their spatio-temporal context as well as the attribute values associated with the individual points of trajectories. Previous work on trajectory visualization addresses selected aspects of this problem, but not all of them. We present a novel approach to visualizing trajectory attribute data. Our solution covers space, time, and attribute values. Based on an analysis of relevant visualization tasks, we designed the visualization solution around the principle of stacking trajectory bands. The core of our approach is a hybrid 2D/3D display. A 2D map serves as a reference for the spatial context, and the trajectories are visualized as stacked 3D trajectory bands along which attribute values are encoded by color. Time is integrated through appropriate ordering of bands and through a dynamic query mechanism that feeds temporally aggregated information to a circular time display. An additional 2D time graph shows temporal information in full detail by stacking 2D trajectory bands. Our solution is equipped with analytical and interactive mechanisms for selecting and ordering of trajectories, and adjusting the color mapping, as well as coordinated highlighting and dedicated 3D navigation. We demonstrate the usefulness of our novel visualization by three examples related to radiation surveillance, traffic analysis, and maritime navigation. User feedback obtained in a small experiment indicates that our hybrid 2D/3D solution can be operated quite well. | false | false | [
"Christian Tominski",
"Heidrun Schumann",
"Gennady L. Andrienko",
"Natalia V. Andrienko"
] | [] | [] | [] |
InfoVis | 2,012 | Taxonomy-Based Glyph Design---with a Case Study on Visualizing Workflows of Biological Experiments | 10.1109/TVCG.2012.271 | Glyph-based visualization can offer elegant and concise presentation of multivariate information while enhancing speed and ease in visual search experienced by users. As with icon designs, glyphs are usually created based on the designers' experience and intuition, often in a spontaneous manner. Such a process does not scale well with the requirements of applications where a large number of concepts are to be encoded using glyphs. To alleviate such limitations, we propose a new systematic process for glyph design by exploring the parallel between the hierarchy of concept categorization and the ordering of discriminative capacity of visual channels. We examine the feasibility of this approach in an application where there is a pressing need for an efficient and effective means to visualize workflows of biological experiments. By processing thousands of workflow records in a public archive of biological experiments, we demonstrate that a cost-effective glyph design can be obtained by following a process of formulating a taxonomy with the aid of computation, identifying visual channels hierarchically, and defining application-specific abstraction and metaphors. | false | false | [
"Eamonn Maguire",
"Philippe Rocca-Serra",
"Susanna-Assunta Sansone",
"Jim Davies",
"Min Chen 0001"
] | [] | [] | [] |
InfoVis | 2,012 | The DeepTree Exhibit: Visualizing the Tree of Life to Facilitate Informal Learning | 10.1109/TVCG.2012.272 | In this paper, we present the DeepTree exhibit, a multi-user, multi-touch interactive visualization of the Tree of Life. We developed DeepTree to facilitate collaborative learning of evolutionary concepts. We will describe an iterative process in which a team of computer scientists, learning scientists, biologists, and museum curators worked together throughout design, development, and evaluation. We present the importance of designing the interactions and the visualization hand-in-hand in order to facilitate active learning. The outcome of this process is a fractal-based tree layout that reduces visual complexity while being able to capture all life on earth; a custom rendering and navigation engine that prioritizes visual appeal and smooth fly-through; and a multi-user interface that encourages collaborative exploration while offering guided discovery. We present an evaluation showing that the large dataset encouraged free exploration, triggers emotional responses, and facilitates visitor engagement and informal learning. | false | false | [
"Florian Block",
"Michael S. Horn",
"Brenda Caldwell Phillips",
"Judy Diamond",
"E. Margaret Evans",
"Chia Shen"
] | [] | [] | [] |
InfoVis | 2,012 | Understanding Pen and Touch Interaction for Data Exploration on Interactive Whiteboards | 10.1109/TVCG.2012.275 | Current interfaces for common information visualizations such as bar graphs, line graphs, and scatterplots usually make use of the WIMP (Windows, Icons, Menus and a Pointer) interface paradigm with its frequently discussed problems of multiple levels of indirection via cascading menus, dialog boxes, and control panels. Recent advances in interface capabilities such as the availability of pen and touch interaction challenge us to re-think this and investigate more direct access to both the visualizations and the data they portray. We conducted a Wizard of Oz study to explore applying pen and touch interaction to the creation of information visualization interfaces on interactive whiteboards without implementing a plethora of recognizers. Our wizard acted as a robust and flexible pen and touch recognizer, giving participants maximum freedom in how they interacted with the system. Based on our qualitative analysis of the interactions our participants used, we discuss our insights about pen and touch interactions in the context of learnability and the interplay between pen and touch gestures. We conclude with suggestions for designing pen and touch enabled interactive visualization interfaces. | false | false | [
"Jagoda Walny",
"Bongshin Lee",
"Paul Johns",
"Nathalie Henry Riche",
"Sheelagh Carpendale"
] | [] | [] | [] |
InfoVis | 2,012 | Visual Semiotics & Uncertainty Visualization: An Empirical Study | 10.1109/TVCG.2012.279 | This paper presents two linked empirical studies focused on uncertainty visualization. The experiments are framed from two conceptual perspectives. First, a typology of uncertainty is used to delineate kinds of uncertainty matched with space, time, and attribute components of data. Second, concepts from visual semiotics are applied to characterize the kind of visual signification that is appropriate for representing those different categories of uncertainty. This framework guided the two experiments reported here. The first addresses representation intuitiveness, considering both visual variables and iconicity of representation. The second addresses relative performance of the most intuitive abstract and iconic representations of uncertainty on a map reading task. Combined results suggest initial guidelines for representing uncertainty and discussion focuses on practical applicability of results. | false | false | [
"Alan M. MacEachren",
"Robert E. Roth",
"James O'Brien",
"Bonan Li",
"Derek Swingley",
"Mark Gahegan"
] | [
"HM"
] | [] | [] |
InfoVis | 2,012 | Visualizing Flow of Uncertainty through Analytical Processes | 10.1109/TVCG.2012.285 | Uncertainty can arise in any stage of a visual analytics process, especially in data-intensive applications with a sequence of data transformations. Additionally, throughout the process of multidimensional, multivariate data analysis, uncertainty due to data transformation and integration may split, merge, increase, or decrease. This dynamic characteristic along with other features of uncertainty pose a great challenge to effective uncertainty-aware visualization. This paper presents a new framework for modeling uncertainty and characterizing the evolution of the uncertainty information through analytical processes. Based on the framework, we have designed a visual metaphor called uncertainty flow to visually and intuitively summarize how uncertainty information propagates over the whole analysis pipeline. Our system allows analysts to interact with and analyze the uncertainty information at different levels of detail. Three experiments were conducted to demonstrate the effectiveness and intuitiveness of our design. | false | false | [
"Yingcai Wu",
"Guo-Xun Yuan",
"Kwan-Liu Ma"
] | [] | [] | [] |
InfoVis | 2,012 | Visualizing Network Traffic to Understand the Performance of Massively Parallel Simulations | 10.1109/TVCG.2012.286 | The performance of massively parallel applications is often heavily impacted by the cost of communication among compute nodes. However, determining how to best use the network is a formidable task, made challenging by the ever increasing size and complexity of modern supercomputers. This paper applies visualization techniques to aid parallel application developers in understanding the network activity by enabling a detailed exploration of the flow of packets through the hardware interconnect. In order to visualize this large and complex data, we employ two linked views of the hardware network. The first is a 2D view, that represents the network structure as one of several simplified planar projections. This view is designed to allow a user to easily identify trends and patterns in the network traffic. The second is a 3D view that augments the 2D view by preserving the physical network topology and providing a context that is familiar to the application developers. Using the massively parallel multi-physics code pF3D as a case study, we demonstrate that our tool provides valuable insight that we use to explain and optimize pF3D's performance on an IBM Blue Gene/P system. | false | false | [
"Aaditya G. Landge",
"Joshua A. Levine",
"Abhinav Bhatele",
"Katherine E. Isaacs",
"Todd Gamblin",
"Martin Schulz 0001",
"Steve H. Langer",
"Peer-Timo Bremer",
"Valerio Pascucci"
] | [] | [] | [] |
InfoVis | 2,012 | Visualizing Student Histories Using Clustering and Composition | 10.1109/TVCG.2012.288 | While intuitive time-series visualizations exist for common datasets, student course history data is difficult to represent using traditional visualization techniques due its concurrent nature. A visual composition process is developed and applied to reveal trends across various groupings. By working closely with educators, analytic strategies and techniques are developed to leverage the visualization composition to reveal unknown trends in the data. Furthermore, clustering algorithms are developed to group common course-grade histories for further analysis. Lastly, variations of the composition process are implemented to reveal subtle differences in the underlying data. These analytic tools and techniques enabled educators to confirm expected trends and to discover new ones. | false | false | [
"David Trimm",
"Penny Rheingans",
"Marie desJardins"
] | [] | [] | [] |
InfoVis | 2,012 | Whisper: Tracing the Spatiotemporal Process of Information Diffusion in Real Time | 10.1109/TVCG.2012.291 | When and where is an idea dispersed? Social media, like Twitter, has been increasingly used for exchanging information, opinions and emotions about events that are happening across the world. Here we propose a novel visualization design, “Whisper”, for tracing the process of information diffusion in social media in real time. Our design highlights three major characteristics of diffusion processes in social media: the temporal trend, social-spatial extent, and community response of a topic of interest. Such social, spatiotemporal processes are conveyed based on a sunflower metaphor whose seeds are often dispersed far away. In Whisper, we summarize the collective responses of communities on a given topic based on how tweets were retweeted by groups of users, through representing the sentiments extracted from the tweets, and tracing the pathways of retweets on a spatial hierarchical layout. We use an efficient flux line-drawing algorithm to trace multiple pathways so the temporal and spatial patterns can be identified even for a bursty event. A focused diffusion series highlights key roles such as opinion leaders in the diffusion process. We demonstrate how our design facilitates the understanding of when and where a piece of information is dispersed and what are the social responses of the crowd, for large-scale events including political campaigns and natural disasters. Initial feedback from domain experts suggests promising use for today's information consumption and dispersion in the wild. | false | false | [
"Nan Cao",
"Yu-Ru Lin",
"Xiaohua Sun",
"David Lazer",
"Shixia Liu",
"Huamin Qu"
] | [] | [] | [] |
EuroVis | 2,012 | A Design Study of Direct-Touch Interaction for Exploratory 3D Scientific Visualization | 10.1111/j.1467-8659.2012.03115.x | We present an interaction design study of several non‐overlapping direct‐touch interaction widgets, postures, and bi‐manual techniques to support the needs of scientists who are exploring a dataset. The final interaction design supports navigation/zoom, cutting plane interaction, a drilling exploration, the placement of seed particles in 3D space, and the exploration of temporal data evolution. To ground our design, we conducted a requirements analysis and used a participatory design approach throughout development. We chose simulations in the field of fluid mechanics as our example domain and, in the paper, discuss our choice of techniques, their adaptation to our target domain, and discuss how they facilitate the necessary combination of visualization control and data exploration. We evaluated our resulting interactive data exploration system with seven fluid mechanics experts and report on their qualitative feedback. While we use flow visualization as our application domain, the developed techniques were designed with generalizability in mind and we discuss several implications of our work on further development of direct‐touch data exploration techniques for scientific visualization in general. | false | false | [
"Tijmen R. Klein",
"Florimond Guéniat",
"Luc Pastur",
"Frédéric Vernier",
"Tobias Isenberg 0001"
] | [] | [] | [] |
EuroVis | 2,012 | A Qualitative Study on the Exploration of Temporal Changes in Flow Maps with Animation and Small-Multiples | 10.1111/j.1467-8659.2012.03093.x | We present a qualitative user study analyzing findings made while exploring changes over time in spatial interactions. We analyzed findings made by the study participants with flow maps, one of the most popular representations of spatial interactions, using animation and small‐multiples as two alternative ways of representing temporal changes. Our goal was not to measure the subjects’ performance with the two views, but to find out whether there are qualitative differences between the types of findings users make with these two representations. To achieve this goal we performed a deep analysis of the collected findings, the interaction logs, and the subjective feedback from the users. We observed that with animation the subjects tended to make more findings concerning geographically local events and changes between subsequent years. With small‐multiples more findings concerning longer time periods were made. Besides, our results suggest that switching from one view to the other might lead to an increase in the numbers of findings of specific types made by the subjects which can be beneficial for certain tasks. | false | false | [
"Ilya Boyandin",
"Enrico Bertini",
"Denis Lalanne"
] | [] | [] | [] |
EuroVis | 2,012 | A Quantized Boundary Representation of 2D Flows | 10.1111/j.1467-8659.2012.03087.x | Analysis and visualization of complex vector fields remain major challenges when studying large scale simulation of physical phenomena. The primary reason is the gap between the concepts of smooth vector field theory and their computational realization. In practice, researchers must choose between either numerical techniques, with limited or no guarantees on how they preserve fundamental invariants, or discrete techniques which limit the precision at which the vector field can be represented. We propose a new representation of vector fields that combines the advantages of both approaches. In particular, we represent a subset of possible streamlines by storing their paths as they traverse the edges of a triangulation. Using only a finite set of streamlines creates a fully discrete version of a vector field that nevertheless approximates the smooth flow up to a user controlled error bound. The discrete nature of our representation enables us to directly compute and classify analogues of critical points, closed orbits, and other common topological structures. Further, by varying the number of divisions (quantizations) used per edge, we vary the resolution used to represent the field, allowing for controlled precision. This representation is compact in memory and supports standard vector field operations. | false | false | [
"Joshua A. Levine",
"Shreeraj Jadhav",
"Harsh Bhatia",
"Valerio Pascucci",
"Peer-Timo Bremer"
] | [] | [] | [] |
EuroVis | 2,012 | A Taxonomy of Visual Cluster Separation Factors | 10.1111/j.1467-8659.2012.03125.x | We provide two contributions, a taxonomy of visual cluster separation factors in scatterplots, and an in‐depth qualitative evaluation of two recently proposed and validated separation measures. We initially intended to use these measures to provide guidance for the use of dimension reduction (DR) techniques and visual encoding (VE) choices, but found that they failed to produce reliable results. To understand why, we conducted a systematic qualitative data study covering a broad collection of 75 real and synthetic high‐dimensional datasets, four DR techniques, and three scatterplot‐based visual encodings. Two authors visually inspected over 800 plots to determine whether or not the measures created plausible results. We found that they failed in over half the cases overall, and in over two‐thirds of the cases involving real datasets. Using open and axial coding of failure reasons and separability characteristics, we generated a taxonomy of visual cluster separability factors. We iteratively refined its explanatory clarity and power by mapping the studied datasets and success and failure ranges of the measures onto the factor axes. Our taxonomy has four categories, ordered by their ability to influence successors: Scale, Point Distance, Shape, and Position. Each category is split into Within‐Cluster factors such as density, curvature, isotropy, and clumpiness, and Between‐Cluster factors that arise from the variance of these properties, culminating in the overarching factor of class separation. The resulting taxonomy can be used to guide the design and the evaluation of cluster separation measures. | false | false | [
"Michael Sedlmair",
"A. Tatu",
"Tamara Munzner",
"Melanie Tory"
] | [] | [] | [] |
EuroVis | 2,012 | Automatic Stream Surface Seeding: A Feature Centered Approach | 10.1111/j.1467-8659.2012.03102.x | The ability to capture and visualize information within the flow poses challenges for visualizing 3D flow fields. Stream surfaces are one of many useful integration based techniques for visualizing 3D flow. However seeding integral surfaces can be challenging. Previous research generally focuses on manual placement of stream surfaces. Little attention has been given to the problem of automatic stream surface seeding. This paper introduces a novel automatic stream surface seeding strategy based on vector field clustering. It is important that the user can define and target particular characteristics of the flow. Our framework provides this ability. The user is able to specify different vector clustering parameters enabling a range of abstraction for the density and placement of seeding curves and their associated stream surfaces. We demonstrate the effectiveness of this automatic stream surface approach on a range of flow simulations and incorporate illustrative visualization techniques. Domain expert evaluation of the results provides valuable insight into the users requirements and effectiveness of our approach. | false | false | [
"Matt Edmunds",
"Robert S. Laramee",
"Rami Malki",
"Ian Masters",
"Nick Croft",
"Guoning Chen",
"Eugene Zhang"
] | [] | [] | [] |
EuroVis | 2,012 | Automating Transfer Function Design with Valley Cell-Based Clustering of 2D Density Plots | 10.1111/j.1467-8659.2012.03122.x | Two‐dimensional transfer functions are an effective and well‐accepted tool in volume classification. The design of them mostly depends on the user's experience and thus remains a challenge. Therefore, we present an approach in this paper to automate the transfer function design based on 2D density plots. By exploiting their smoothness, we adopted the Morse theory to automatically decompose the feature space into a set of valley cells. We design a simplification process based on cell separability to eliminate cells which are mainly caused by noise in the original volume data. Boundary persistence is first introduced to measure the separability between adjacent cells and to suitably merge them. Afterward, a reasonable classification result is achieved where each cell represents a potential feature in the volume data. This classification procedure is automatic and facilitates an arbitrary number and shape of features in the feature space. The opacity of each feature is determined by its persistence and size. To further incorporate the user's prior knowledge, a hierarchical feature representation is created by successive merging of the cells. With this representation, the user is allowed to merge or split features of interest and set opacity and color freely. Experiments on various volumetric data sets demonstrate the effectiveness and usefulness of our approach in transfer function generation. | false | false | [
"Yunhai Wang",
"Jian Zhang 0070",
"Dirk J. Lehmann",
"Holger Theisel",
"Xuebin Chi"
] | [] | [] | [] |
EuroVis | 2,012 | Biopsy Planner - Visual Analysis for Needle Pathway Planning in Deep Seated Brain Tumor Biopsy | 10.1111/j.1467-8659.2012.03101.x | Biopsies involve taking samples from living tissue using a biopsy needle. In current clinical practice they are a first mandatory step before any further medical actions are planned. Performing a biopsy on a deep seated brain tumor requires considerable time for establishing and validating the desired biopsy needle pathway to avoid damage. In this paper, we present a system for the visualization, analysis, and validation of biopsy needle pathways. Our system uses a multi‐level approach for identifying stable needle placements which minimize the risk of hitting blood vessels. This is one of the major dangers in this type of intervention. Our approach helps in identifying and visualizing the point on the pathway that is closest to a surrounding blood vessel, requiring a closer inspection by the neurosurgeon. An evaluation by medical experts is performed to demonstrate the utility of our system. | false | false | [
"Paul-Corneliu Herghelegiu",
"Vasile-Ion Manta",
"Radu Perin",
"Stefan Bruckner",
"M. Eduard Gröller"
] | [] | [] | [] |
EuroVis | 2,012 | Comparative Evaluation of an Interactive Time-Series Visualization that Combines Quantitative Data with Qualitative Abstractions | 10.1111/j.1467-8659.2012.03092.x | In many application areas, analysts have to make sense of large volumes of multivariate time‐series data. Explorative analysis of this kind of data is often difficult and overwhelming at the level of raw data. Temporal data abstraction reduces data complexity by deriving qualitative statements that reflect domain‐specific key characteristics. Visual representations of abstractions and raw data together with appropriate interaction methods can support analysts in making their data easier to understand. Such a visualization technique that applies smooth semantic zooming has been developed in the context of patient data analysis. However, no empirical evidence on its effectiveness and efficiency is available. In this paper, we aim to fill this gap by reporting on a controlled experiment that compares this technique with another visualization method used in the well‐known KNAVE‐II framework. Both methods integrate quantitative data with qualitative abstractions whereas the first one uses a composite representation with color‐coding to display the qualitative data and spatial position coding for the quantitative data. The second technique uses juxtaposed representations for quantitative and qualitative data with spatial position coding for both. Results show that the test persons using the composite representation were generally faster, particularly for more complex tasks that involve quantitative values as well as qualitative abstractions. | false | false | [
"Wolfgang Aigner",
"Alexander Rind",
"Stephan Hoffmann"
] | [] | [
"PW",
"P",
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}
] |
EuroVis | 2,012 | Comparative Visual Analysis of 2D Function Ensembles | 10.1111/j.1467-8659.2012.03112.x | In the development process of powertrain systems, 2D function ensembles frequently occur in the context of multi‐run simulations. An analysis has many facets, including distributions of extracted features, comparisons between ensemble members and target functions, and details‐on‐demand. The primary contribution of this paper is a design study of an interactive approach for a comparative visual analysis of 2D function ensembles. The design focuses on a tight integration of domain‐oriented and member‐oriented visualization techniques, and it seeks to preserve the mental model of 2D functions on multiple levels of detail. In this context, we propose a novel focus+context approach for visualizations relying on data‐driven placement which is based on labeling. We also extend work on feature‐preserving downsampling of 2D functions. Our design supports a comparison of 2D functions based on juxtaposition, overlay, and explicit differences. It also enables an analysis in terms of extracted scalar features and 1D aggregations. An evaluation illustrates a workflow in our application context. User feedback indicates a time saving of 70% for common tasks and a qualitative gain for the entire development process. | false | false | [
"Harald Piringer",
"Stephan Pajer",
"Wolfgang Berger",
"H. Teichmann"
] | [] | [] | [] |
EuroVis | 2,012 | Computing Voronoi Treemaps: Faster, Simpler, and Resolution-independent | 10.1111/j.1467-8659.2012.03078.x | Voronoi treemaps represent hierarchies as nested polygons. We here show that, contrary to the apparent popular belief, utilization of an algorithm for weighted Voronoi diagrams is not only feasible, but also more efficient than previous low‐resolution approximations, even when the latter are implemented on graphics hardware. More precisely, we propose an instantiation of Lloyd's method for centroidal Voronoi diagrams with Aurenhammer's algorithm for power diagrams that yields an algorithm running in 𝒪(n log n) rather than Ω(n2) time per iteration, with n the number of sites. We describe its implementation and present evidence that it is faster also in practice. | false | false | [
"Arlind Nocaj",
"Ulrik Brandes"
] | [
"BP"
] | [] | [] |
EuroVis | 2,012 | Conceptualizing Visual Uncertainty in Parallel Coordinates | 10.1111/j.1467-8659.2012.03094.x | Uncertainty is an intrinsic part of any visual representation in visualization, no matter how precise the input data. Existing research on uncertainty in visualization mainly focuses on depicting data‐space uncertainty in a visual form. Uncertainty is thus often seen as a problem to deal with, in the data, and something to be avoided if possible. In this paper, we highlight the need for analyzing visual uncertainty in order to design more effective visual representations. We study various forms of uncertainty in the visual representation of parallel coordinates and propose a taxonomy for categorizing them. By building a taxonomy, we aim to identify different sources of uncertainty in the screen space and relate them to different effects of uncertainty upon the user. We examine the literature on parallel coordinates and apply our taxonomy to categorize various techniques for reducing uncertainty. In addition, we consider uncertainty from a different perspective by identifying cases where increasing certain forms of uncertainty may even be useful, with respect to task, data type and analysis scenario. This work suggests that uncertainty is a feature that can be both useful and problematic in visualization, and it is beneficial to augment an information visualization pipeline with a facility for visual uncertainty analysis. | false | false | [
"Aritra Dasgupta",
"Min Chen 0001",
"Robert Kosara"
] | [] | [] | [] |
EuroVis | 2,012 | ConnectedCharts: Explicit Visualization of Relationships between Data Graphics | 10.1111/j.1467-8659.2012.03121.x | Multidimensional multivariate data can be visualized using many different well‐known charts, such as bar charts, stacked bar charts, grouped bar charts, scatterplots, or pivot tables, or also using more advanced high‐dimensional techniques such as scatterplot matrices (SPLOMs) or parallel coordinate plots (PCPs). These many techniques have different advantages, and users may wish to use several charts or data graphics to understand a dataset from different perspectives. We present ConnectedCharts, a technique for displaying relationships between multiple charts. ConnectedCharts allow for hybrid combinations of bar charts, scatterplots, and parallel coordinates, with curves drawn to show the conceptual links between charts. The charts can be thought of as coordinated views, where linking is achieved not only through interactive brushing, but also with explicitly drawn curves that connect corresponding data tuples or axes. We present a formal description of a design space of many simple charts, and also identify different kinds of connections that can be displayed between related charts. Our prototype implementation demonstrates how the connections between multiple charts can make relationships clearer and can serve to document the history of a user's analytical process, leading to potential applications in visual analytics and dashboard design. | false | false | [
"Christophe Viau",
"Michael J. McGuffin"
] | [] | [] | [] |
EuroVis | 2,012 | COVRA: A compression-domain output-sensitive volume rendering architecture based on a sparse representation of voxel blocks | 10.1111/j.1467-8659.2012.03124.x | We present a novel multiresolution compression‐domain GPU volume rendering architecture designed for interactive local and networked exploration of rectilinear scalar volumes on commodity platforms. In our approach, the volume is decomposed into a multiresolution hierarchy of bricks. Each brick is further subdivided into smaller blocks, which are compactly described by sparse linear combinations of prototype blocks stored in an overcomplete dictionary. The dictionary is learned, using limited computational and memory resources, by applying the K‐SVD algorithm to a re‐weighted non‐uniformly sampled subset of the input volume, harnessing the recently introduced method of coresets. The result is a scalable high quality coding scheme, which allows very large volumes to be compressed off‐line and then decompressed on‐demand during real‐time GPU‐accelerated rendering. Volumetric information can be maintained in compressed format through all the rendering pipeline. In order to efficiently support high quality filtering and shading, a specialized real‐time renderer closely coordinates decompression with rendering, combining at each frame images produced by raycasting selectively decompressed portions of the current view‐ and transfer‐function‐dependent working set. The quality and performance of our approach is demonstrated on massive static and time‐varying datasets. | false | false | [
"Enrico Gobbetti",
"José Antonio Iglesias Guitián",
"Fabio Marton"
] | [] | [] | [] |
EuroVis | 2,012 | Document Thumbnails with Variable Text Scaling | 10.1111/j.1467-8659.2012.03109.x | Document reader applications usually offer an overview of the layout for each page as thumbnail views. Reading the text in these becomes impossible when the font size becomes very small. We improve the readability of these thumbnails using a distortion method, which retains a readable font size of interesting text while shrinking less interesting text further. In contrast to existing approaches, our method preserves the global layout of a page and is able to show context around important terms. We evaluate our technique and show application examples. | false | false | [
"Andreas Stoffel",
"Hendrik Strobelt",
"Oliver Deussen",
"Daniel A. Keim"
] | [] | [] | [] |
EuroVis | 2,012 | Drawing Large Graphs by Low-Rank Stress Majorization | 10.1111/j.1467-8659.2012.03090.x | Optimizing a stress model is a natural technique for drawing graphs: one seeks an embedding into Rd which best preserves the induced graph metric. Current approaches to solving the stress model for a graph with |𝒱| nodes and |ɛ| edges require the full all‐pairs shortest paths (APSP) matrix, which takes O(|𝒱|2 log |ɛ|+|𝒱‖ɛ|) time and O(|𝒱|2) space. We propose a novel algorithm based on a low‐rank approximation to the required matrices. The crux of our technique is an observation that it is possible to approximate the full APSP matrix, even when only a small subset of its entries are known. Our algorithm takes time O(k|𝒱|+|𝒱|log|𝒱|+|ɛ|) per iteration with a preprocessing time of O(k3+ k(|ɛ|+|𝒱| log |𝒱|) + k2|𝒱|) and memory usage of O(k|𝒱|), where a user‐defined parameter k trades off quality of approximation with running time and space. We give experimental results which show, to the best of our knowledge, the largest (albeit approximate) full stress model based layouts to date. | false | false | [
"Marc Khoury",
"Yifan Hu 0001",
"Shankar Krishnan",
"Carlos Eduardo Scheidegger"
] | [] | [] | [] |
EuroVis | 2,012 | Employing 2D Projections for Fast Visual Exploration of Large Fiber Tracking Data | 10.1111/j.1467-8659.2012.03100.x | Fiber tracts detection is an increasingly common technology for diagnosis and also understanding of brain function. Although tools for tracing and presenting brain fibers are advanced, it is still difficult for physicians or students to explore the dataset in 3D due to their intricate topology. In this work we present a visual exploration approach for fiber tracts data aimed at supporting exploration of such data. The work employs a local, precise and fast 2D multidimensional projection technique that allows a large number of fibers to be handled simultaneously and to select groups of bundled fibers for further exploration. In this approach, a DTI feature dataset, including curvature as well as spatial features, is projected on a 2D or 3D view. By handling groups formed in this view, exploration is linked to corresponding brain fibers in object space. The link exists in both directions and fibers selected in object space are also mapped to feature space. Our approach also allows users to modify the projection, controlling and improving, if necessary, the definition of groups of fibers for small and large datasets, due to the local nature of the projection. Compared to other related work, the method presented here is faster for creating visual representations, making it possible to explore complete sets of fibers tracts up to 250K fibers, which was not possible previously. Additionally, the ability to change configuration of the feature space representation adds a high degree of flexibility to the process. | false | false | [
"Jorge Poco",
"Danilo Medeiros Eler",
"Fernando Vieira Paulovich",
"Rosane Minghim"
] | [] | [] | [] |
EuroVis | 2,012 | Graph Bundling by Kernel Density Estimation | 10.1111/j.1467-8659.2012.03079.x | We present a fast and simple method to compute bundled layouts of general graphs. For this, we first transform a given graph drawing into a density map using kernel density estimation. Next, we apply an image sharpening technique which progressively merges local height maxima by moving the convolved graph edges into the height gradient flow. Our technique can be easily and efficiently implemented using standard graphics acceleration techniques and produces graph bundlings of similar appearance and quality to state‐of‐the‐art methods at a fraction of the cost. Additionally, we show how to create bundled layouts constrained by obstacles and use shading to convey information on the bundling quality. We demonstrate our method on several large graphs. | false | false | [
"Christophe Hurter",
"Ozan Ersoy",
"Alexandru C. Telea"
] | [] | [] | [] |
EuroVis | 2,012 | I-SI: Scalable Architecture for Analyzing Latent Topical-Level Information From Social Media Data | 10.1111/j.1467-8659.2012.03120.x | We present a general visual analytics architecture that is designed and implemented to effectively analyze unstructured social media data on a large scale. Pipelined on a high‐performance cluster configuration, MPI processing, and interactive visual analytics interfaces, our architecture, I‐SI, closely integrates data‐driven analytical methods and user‐centered visual analytics. It creates a coherent analysis environment for identifying event structures, geographical distributions, and key indicators of emerging events. This environment supports monitoring, analyzing, and responding to latent information extracted from social media. We have applied the I‐SI architecture to collect social media data, analyze the data on a large scale and uncover the latent social phenomena. To demonstrate the efficacy and applicability of I‐SI, we describe several social media use cases in multiple domains that were evaluated by experts. The use cases demonstrate that I‐SI can benefit a range of users by constructing meaningful event structures and identifying precursors to critical events within a rich, evolving set of topics. | false | false | [
"Xiaoyu Wang 0001",
"Wenwen Dou",
"Zhiqiang Ma 0004",
"J. Villalobos",
"Yang Chen",
"Thomas Kraft",
"William Ribarsky"
] | [] | [] | [] |
EuroVis | 2,012 | Illustrative Membrane Clipping | 10.1111/j.1467-8659.2012.03083.x | Clipping is a fast, common technique for resolving occlusions. It only requires simple interaction, is easily understandable, and thus has been very popular for volume exploration. However, a drawback of clipping is that the technique indiscriminately cuts through features. Illustrators, for example, consider the structures in the vicinity of the cut when visualizing complex spatial data and make sure that smaller structures near the clipping plane are kept in the image and not cut into fragments. In this paper we present a new technique, which combines the simple clipping interaction with automated selective feature preservation using an elastic membrane. In order to prevent cutting objects near the clipping plane, the deformable membrane uses underlying data properties to adjust itself to salient structures. To achieve this behaviour, we translate data attributes into a potential field which acts on the membrane, thus moving the problem of deformation into the soft‐body dynamics domain. This allows us to exploit existing GPU‐based physics libraries which achieve interactive frame rates. For manual adjustment, the user can insert additional potential fields, as well as pinning the membrane to interesting areas. We demonstrate that our method can act as a flexible and non‐invasive replacement of traditional clipping planes. | false | false | [
"Åsmund Birkeland",
"Stefan Bruckner",
"Andrea Brambilla",
"Ivan Viola"
] | [] | [] | [] |
EuroVis | 2,012 | Importance Driven Automatic Color Design for Direct Volume Rendering | 10.1111/j.1467-8659.2012.03123.x | This paper introduces an automatic color design method that is driven by an importance function of the objects within a volumetric dataset. Our method allows the user to intuitively modify the object classification and the importance distribution function in the 2D rendered image. It automatically computes the transfer function, especially the color distribution, to convey the importance of the objects. In our approach, the importance of an object is represented as the attentiveness of a color. In addition, we preserve the color harmony in the rendered image in order to provide a visually pleasing result. In this paper, we propose a set of computational measurements to compute the color attentiveness and color harmony. Our color assignment algorithm supports arbitrary‐dimensional transfer functions and obtains interactive frame rates. Our method involves three color spaces, namely Coloroid system, CIE LChuv, and Adobe RGB color space. It calculates the color attentiveness in CIE LChuv space, and the color harmony in Coloroid system. It, then, assigns the transfer function in a dual space of Adobe RGB space and renders the resulting image in Adobe RGB space. We conducted a detailed user study, which proves that our method successfully conveys the importance distributions. Our contribution in this paper is not only our importance driven approach, but also our computational measurements and our color assignment algorithm. | false | false | [
"Lei Wang 0024",
"Arie E. Kaufman"
] | [] | [] | [] |
EuroVis | 2,012 | Interactive Rendering of Materials and Biological Structures on Atomic and Nanoscopic Scale | 10.1111/j.1467-8659.2012.03128.x | The properties of both inorganic and organic materials and the function of biological structures can often only be understood by analyzing them simultaneously on atomic and nanoscopic, if not mesoscopic, scale. Here, the problem arises to render millions to billions of atoms. We propose a method by which it is possible to interactively visualize atomic data, bridging five orders of magnitude in length scale. For this, we propose a simple yet efficient GPU rendering method that enables interactive visualization of biological structures consisting of up to several billions of atoms. To be able to load all atomic data onto the GPU, we exploit the fact that biological structures often consist of recurring molecular substructures. We also exploit that these objects typically are rendered opaquely, so that only a fraction of the atoms is visible. The method is demonstrated on both biological structures as well as atom probe tomography data of an inorganic specimen. We conclude with a discussion about when ‐during ascension from atomic to mesoscopic scale – level‐of‐detail representations become necessary. | false | false | [
"Norbert Lindow",
"Daniel Baum",
"Hans-Christian Hege"
] | [] | [] | [] |
EuroVis | 2,012 | Interactive Visualization of Generalized Virtual 3D City Models using Level-of-Abstraction Transitions | 10.1111/j.1467-8659.2012.03081.x | Virtual 3D city models play an important role in the communication of complex geospatial information in a growing number of applications, such as urban planning, navigation, tourist information, and disaster management. In general, homogeneous graphic styles are used for visualization. For instance, photorealism is suitable for detailed presentations, and non‐photorealism or abstract stylization is used to facilitate guidance of a viewer's gaze to prioritized information. However, to adapt visualization to different contexts and contents and to support saliency‐guided visualization based on user interaction or dynamically changing thematic information, a combination of different graphic styles is necessary. Design and implementation of such combined graphic styles pose a number of challenges, specifically from the perspective of real‐time 3D visualization. In this paper, the authors present a concept and an implementation of a system that enables different presentation styles, their seamless integration within a single view, and parametrized transitions between them, which are defined according to tasks, camera view, and image resolution. The paper outlines potential usage scenarios and application fields together with a performance evaluation of the implementation. | false | false | [
"Amir Semmo",
"Matthias Trapp 0001",
"Jan Eric Kyprianidis",
"Jürgen Döllner"
] | [] | [] | [] |
EuroVis | 2,012 | Interface Exchange as an Indicator for Eddy Heat Transport | 10.1111/j.1467-8659.2012.03105.x | The ocean contains many large‐scale, long‐lived vortices, called mesoscale eddies, that are believed to have a role in the transport and redistribution of salt, heat, and nutrients throughout the ocean. Determining this role, however, has proven to be a challenge, since the mechanics of eddies are only partly understood; a standard definition for these ocean eddies does not exist and, therefore, scientifically meaningful, robust methods for eddy extraction, characterization, tracking and visualization remain a challenge. To shed light on the nature and potential roles of eddies, we extend our previous work on eddy identification and tracking to construct a new metric to characterize the transfer of water into and out of eddies across their boundary, and produce several visualizations of this new metric to provide clues about the role eddies play in the global ocean. | false | false | [
"Sean Williams",
"Mark R. Petersen",
"Matthew Hecht",
"Mathew Maltrud",
"John Patchett",
"James P. Ahrens",
"Bernd Hamann"
] | [] | [] | [] |
EuroVis | 2,012 | iVisClustering: An Interactive Visual Document Clustering via Topic Modeling | 10.1111/j.1467-8659.2012.03108.x | Clustering plays an important role in many large‐scale data analyses providing users with an overall understanding of their data. Nonetheless, clustering is not an easy task due to noisy features and outliers existing in the data, and thus the clustering results obtained from automatic algorithms often do not make clear sense. To remedy this problem, automatic clustering should be complemented with interactive visualization strategies. This paper proposes an interactive visual analytics system for document clustering, called iVisClustering, based on a widely‐used topic modeling method, latent Dirichlet allocation (LDA). iVisClustering provides a summary of each cluster in terms of its most representative keywords and visualizes soft clustering results in parallel coordinates. The main view of the system provides a 2D plot that visualizes cluster similarities and the relation among data items with a graph‐based representation. iVisClustering provides several other views, which contain useful interaction methods. With help of these visualization modules, we can interactively refine the clustering results in various ways. Keywords can be adjusted so that they characterize each cluster better. In addition, our system can filter out noisy data and re‐cluster the data accordingly. Cluster hierarchy can be constructed using a tree structure and for this purpose, the system supports cluster‐level interactions such as sub‐clustering, removing unimportant clusters, merging the clusters that have similar meanings, and moving certain clusters to any other node in the tree structure. Furthermore, the system provides document‐level interactions such as moving mis‐clustered documents to another cluster and removing useless documents. Finally, we present how interactive clustering is performed via iVisClustering by using real‐world document data sets. | false | false | [
"Hanseung Lee",
"Jaeyeon Kihm",
"Jaegul Choo",
"John T. Stasko",
"Haesun Park"
] | [] | [] | [] |
EuroVis | 2,012 | Kelp Diagrams: Point Set Membership Visualization | 10.1111/j.1467-8659.2012.03080.x | We present Kelp Diagrams, a novel method to depict set relations over points, i.e., elements with predefined positions. Our method creates schematic drawings and has been designed to take aesthetic quality, efficiency, and effectiveness into account. This is achieved by a routing algorithm, which links elements that are part of the same set by constructing minimum cost paths over a tangent visibility graph. There are two styles of Kelp Diagrams to depict overlapping sets, a nested and a striped style, each with its own strengths and weaknesses. We compare Kelp Diagrams with two existing methods and show that our approach provides a more consistent and clear depiction of both element locations and their set relations. | false | false | [
"Kasper Dinkla",
"Marc J. van Kreveld",
"Bettina Speckmann",
"Michel A. Westenberg"
] | [] | [] | [] |
EuroVis | 2,012 | Magnetic Flux Topology of 2D Point Dipoles | 10.1111/j.1467-8659.2012.03088.x | Magnetic fields exhibit higher‐order, nonlinear singularities in the form of point‐dipole singularities. In addition, due to absence of divergence, they feature only a subset of invariant structures from traditional vector field topology. For magnetic fields of sets of point dipoles—widely present in physics and often used as an approximation—we present a technique revealing the topology of magnetic flux. The flux topology is identified with areas covered by field lines that directly connect pairs of dipoles. We introduce the dipole connectrix as a reduced one‐manifold representation of those areas. The set of connectrices serves as our concise visualization of the global structure of magnetic flux. In addition, the quantitative values of flux are displayed by the thickness of the connectrices. We evaluate our technique for simulations of ferroparticle monolayers and magnetic gels. | false | false | [
"Sven Bachthaler",
"Filip Sadlo",
"Rudolf Weeber",
"Sofia Kantorovich",
"Christian Holm",
"Daniel Weiskopf"
] | [] | [] | [] |
EuroVis | 2,012 | MarketAnalyzer: An Interactive Visual Analytics System for Analyzing Competitive Advantage Using Point of Sale Data | 10.1111/j.1467-8659.2012.03117.x | Competitive intelligence is a systematic approach for gathering, analyzing, and managing information to make informed business decisions. Many companies use competitive intelligence to identify risks and opportunities within markets. Point of sale data that retailers share with vendors is of critical importance in developing competitive intelligence. However, existing tools do not easily enable the analysis of such large and complex data. therefore, new approaches are needed in order to facilitate better analysis and decision making. In this paper, we present MarketAnalyzer, an interactive visual analytics system designed to allow vendors to increase their competitive intelligence. MarketAnalyzer utilizes pixel‐based matrices to present sale data, trends, and market share growths of products of the entire market within a single display. These matrices are augmented by advanced underlying analytical methods to enable the quick evaluation of growth and risk within market sectors. Furthermore, our system enables the aggregation of point of sale data in geographical views that provide analysts with the ability to explore the impact of regional demographics and trends. Additionally, overview and detailed information is provided through a series of coordinated multiple views. In order to demonstrate the effectiveness of our system, we provide two use‐case scenarios as well as feedback from market analysts. | false | false | [
"Sungahn Ko",
"Ross Maciejewski",
"Yun Jang",
"David S. Ebert"
] | [] | [] | [] |
EuroVis | 2,012 | MatchPad: Interactive Glyph-Based Visualization for Real-Time Sports Performance Analysis | 10.1111/j.1467-8659.2012.03118.x | Today real‐time sports performance analysis is a crucial aspect of matches in many major sports. For example, in soccer and rugby, team analysts may annotate videos during the matches by tagging specific actions and events, which typically result in some summary statistics and a large spreadsheet of recorded actions and events. To a coach, the summary statistics (e.g., the percentage of ball possession) lacks sufficient details, while reading the spreadsheet is time‐consuming and making decisions based on the spreadsheet in real‐time is thereby impossible. In this paper, we present a visualization solution to the current problem in real‐time sports performance analysis. We adopt a glyph‐based visual design to enable coaching staff and analysts to visualize actions and events “at a glance”. We discuss the relative merits of metaphoric glyphs in comparison with other types of glyph designs in this particular application. We describe an algorithm for managing the glyph layout at different spatial scales in interactive visualization. We demonstrate the use of this technical approach through its application in rugby, for which we delivered the visualization software, MatchPad, on a tablet computer. The MatchPad was used by the Welsh Rugby Union during the Rugby World Cup 2011. It successfully helped coaching staff and team analysts to examine actions and events in detail whilst maintaining a clear overview of the match, and assisted in their decision making during the matches. It also allows coaches to convey crucial information back to the players in a visually‐engaging manner to help improve their performance. | false | false | [
"Philip A. Legg",
"David H. S. Chung",
"Matthew L. Parry",
"Mark W. Jones",
"R. Long",
"Iwan W. Griffiths",
"Min Chen 0001"
] | [] | [] | [] |
EuroVis | 2,012 | Multi-layer illustrative dense flow visualization | 10.1111/j.1467-8659.2012.03082.x | We present a dense visualization of vector fields on multi‐layered surfaces. The method is based on the illustration buffer, which provides a screen space representation of the surface, where each pixel stores a list of all surface layers. This representation is implemented on the GPU using shaders and leads to a fast output sensitive technique. In our approach, we first use procedural noise to create an initial spot pattern on the surface that has both an almost constant screen space frequency and is view independent. Then, we perform anisotropic diffusion simultaneously on all surface layers using a discretization scheme that maintains second order convergence while only accessing the four neighboring pixels. Finally, we enhance this result with illustrative techniques and composite the final image. Our method works with time‐evolving surfaces, time‐dependent vector fields, and moving cameras. We apply our method to CFD data sets from engineering and astronomy as well as synthetic velocity fields. | false | false | [
"Robert Carnecky",
"Benjamin Schindler",
"Raphael Fuchs",
"Ronald Peikert"
] | [] | [] | [] |
EuroVis | 2,012 | Nearly Recurrent Components in 3D Piecewise Constant Vector Fields | 10.1111/j.1467-8659.2012.03104.x | We present an algorithm for computing nearly recurrent components, that represent areas of close to circulating or stagnant flow, for 3D piecewise constant (PC) vector fields defined on regular grids. Using a number of analytical and simulated data sets, we demonstrate that nearly recurrent components can provide interesting insight into the topological structure of 3D vector fields.Our approach is based on prior work on Morse decompositions for PC vector fields on surfaces and extends concepts previously developed with this goal in mind to the case of 3D vector fields defined on regular grids. Our contributions include a description of trajectories of 3D piecewise constant vector fields and an extension of the transition graph, a finite directed graph that represents all trajectories, to the 3D case. Nearly recurrent components are defined by strongly connected components of the transition graph. | false | false | [
"Andrzej Szymczak",
"Nicholas Brunhart-Lupo"
] | [] | [] | [] |
EuroVis | 2,012 | Parallel Computation of 3D Morse-Smale Complexes | 10.1111/j.1467-8659.2012.03089.x | The Morse‐Smale complex is a topological structure that captures the behavior of the gradient of a scalar function on a manifold. This paper discusses scalable techniques to compute the Morse‐Smale complex of scalar functions defined on large three‐dimensional structured grids. Computing the Morse‐Smale complex of three‐dimensional domains is challenging as compared to two‐dimensional domains because of the non‐trivial structure introduced by the two types of saddle criticalities. We present a parallel shared‐memory algorithm to compute the Morse‐Smale complex based on Forman's discrete Morse theory. The algorithm achieves scalability via synergistic use of the CPU and the GPU. We first prove that the discrete gradient on the domain can be computed independently for each cell and hence can be implemented on the GPU. Second, we describe a two‐step graph traversal algorithm to compute the 1‐saddle‐2‐saddle connections efficiently and in parallel on the CPU. Simultaneously, the extremasaddle connections are computed using a tree traversal algorithm on the GPU. | false | false | [
"Nithin Shivashankar",
"Vijay Natarajan"
] | [] | [] | [] |
EuroVis | 2,012 | Perception of Animated Node-Link Diagrams for Dynamic Graphs | 10.1111/j.1467-8659.2012.03113.x | Effective visualization of dynamic graphs remains an open research topic, and many state‐of‐the‐art tools use animated node‐link diagrams for this purpose. Despite its intuitiveness, the effectiveness of animation in node‐link diagrams has been questioned, and several empirical studies have shown that animation is not necessarily superior to static visualizations. However, the exact mechanics of perceiving animated node‐link diagrams are still unclear. In this paper, we study the impact of different dynamic graph metrics on user perception of the animation. After deriving candidate visual graph metrics, we perform an exploratory user study where participants are asked to reconstruct the event sequence in animated node‐link diagrams. Based on these findings, we conduct a second user study where we investigate the most important visual metrics in depth. Our findings show that node speed and target separation are prominent visual metrics to predict the performance of event sequencing tasks. | false | false | [
"Sohaib Ghani",
"Niklas Elmqvist",
"Ji Soo Yi"
] | [] | [] | [] |
EuroVis | 2,012 | PORGY: A Visual Graph Rewriting Environment for Complex Systems | 10.1111/j.1467-8659.2012.03119.x | Graph rewriting systems (GRSs) operate on graphs by substituting local patterns according to a set of rewriting rules. The apparent simplicity of GRSs hides an incredible complexity and turns the study of these systems into an involved task requiring high‐level expertise. We designed PORGY, an interactive visual environment to fully support GRSs related tasks, exploiting a long historical tradition of GRSs with node‐link representations of graphs. PORGY enables rule‐based modeling and simulation steering through graphical representations and direct manipulation of all GRSs components. This paper contributes a design study and task taxonomy relevant to the interactive visualization of GRSs. | false | false | [
"Bruno Pinaud",
"Guy Melançon",
"Jonathan Dubois"
] | [] | [] | [] |
EuroVis | 2,012 | Porosity Maps - Interactive Exploration and Visual Analysis of Porosity in Carbon Fiber Reinforced Polymers | 10.1111/j.1467-8659.2012.03111.x | In this work a novel method for the characterization of porosity in carbon fiber reinforced polymers (CFRP) is presented. A visualization pipeline for the interactive exploration and visual analysis of CFRP specimens is developed to enhance the evaluation workflow for non‐destructive testing (NDT) practitioners based on specified tasks. Besides quantitative porosity determination and the calculation of local pore properties, i.e., volume, surface, dimensions and shape factors, we employ a drill‐down approach to explore pores in a CFRP specimen. We introduce Porosity Maps (PM), to allow for a fast porosity evaluation of the specimen. Pores are filtered in two stages. First a region of interest is selected in the porosity maps. Second, pores are filtered with parallel coordinates according to their local properties. Furthermore a histogram‐based best‐viewpoint widget was implemented to visualize the quality of viewpoints on a sphere. The advantages of our approach are demonstrated using real world CFRP specimens. We are able to show that our visualization‐driven approach leads to a better evaluation of CFRP components than existing reference methods. | false | false | [
"Andreas Reh",
"B. Plank",
"Johann Kastner",
"M. Eduard Gröller",
"Christoph Heinzl"
] | [] | [] | [] |
EuroVis | 2,012 | Probabilistic Local Features in Uncertain Vector Fields with Spatial Correlation | 10.1111/j.1467-8659.2012.03097.x | In this paper methods for extraction of local features in crisp vector fields are extended to uncertain fields. While in a crisp field local features are either present or absent at some location, in an uncertain field they are present with some probability. We model sampled uncertain vector fields by discrete Gaussian random fields with empirically estimated spatial correlations. The variability of the random fields in a spatial neighborhood is characterized by marginal distributions. Probabilities for the presence of local features are formulated in terms of low‐dimensional integrals over such marginal distributions. Specifically, we define probabilistic equivalents for critical points and vortex cores. The probabilities are computed by Monte Carlo integration. For identification of critical points and cores of swirling motion we employ the Poincaré index and the criterion by Sujudi and Haimes. In contrast to previous global methods we take a local perspective and directly extract features in divergence‐free fields as well. The method is able to detect saddle points in a straight forward way and works on various grid types. It is demonstrated by applying it to simulated unsteady flows of biofluid and climate dynamics. | false | false | [
"Christoph Petz",
"Kai Pöthkow",
"Hans-Christian Hege"
] | [] | [] | [] |
EuroVis | 2,012 | Procedural Texture Synthesis for Zoom-Independent Visualization of Multivariate Data | 10.1111/j.1467-8659.2012.03127.x | Simultaneous visualization of multiple continuous data attributes in a single visualization is a task that is important for many application areas. Unsurprisingly, many methods have been proposed to solve this task. However, the behavior of such methods during the exploration stage, when the user tries to understand the data with panning and zooming, has not been given much attention.In this paper, we propose a method that uses procedural texture synthesis to create zoom‐independent visualizations of three scalar data attributes. The method is based on random‐phase Gabor noise, whose frequency is adapted for the visualization of the first data attribute. We ensure that the resulting texture frequency lies in the range that is perceived well by the human visual system at any zoom level. To enhance the perception of this attribute, we also apply a specially constructed transfer function that is based on statistical properties of the noise. Additionally, the transfer function is constructed in a way that it does not introduce any aliasing to the texture. We map the second attribute to the texture orientation. The third attribute is color coded and combined with the texture by modifying the value component of the HSV color model. The necessary contrast needed for texture and color perception was determined in a user study. In addition, we conducted a second user study that shows significant advantages of our method over current methods with similar goals. We believe that our method is an important step towards creating methods that not only succeed in visualizing multiple data attributes, but also adapt to the behavior of the user during the data exploration stage. | false | false | [
"Rostislav Khlebnikov",
"Bernhard Kainz",
"Markus Steinberger",
"Marc Streit",
"Dieter Schmalstieg"
] | [] | [] | [] |
EuroVis | 2,012 | Reliable Adaptive Modelling of Vascular Structures with Non-Circular Cross-Sections | 10.1111/j.1467-8659.2012.03098.x | Accurate visualizations of complex vascular structures are essential for medical applications, such as diagnosis, therapy planning and medical education. Vascular trees are usually described using centerlines, since they capture both the topology and the geometry of the vasculature in an intuitive manner. State‐of‐the‐art vessel segmentation algorithms deliver vascular outlines as free‐form contours along the centerline, since this allows capturing anatomical pathologies. However, existing methods for generating surface representations from centerlines can only cope with circular outlines. We present a novel model‐based technique that is capable of generating intersection‐free surfaces from centerlines with complex outlines. Vascular segments are described by local signed distance functions and combined using Boolean operations. An octree‐based surface generation strategy automatically computes watertight, scale‐adaptive meshes with a controllable quality. In contrast to other approaches, our method generates a reliable representation that guarantees to capture all vessels regardless of their size. | false | false | [
"Jan Kretschmer",
"Thomas Beck 0001",
"Christian Tietjen",
"Bernhard Preim",
"Marc Stamminger"
] | [] | [] | [] |
EuroVis | 2,012 | Rolled-out Wordles: A Heuristic Method for Overlap Removal of 2D Data Representatives | 10.1111/j.1467-8659.2012.03106.x | When representing 2D data points with spacious objects such as labels, overlap can occur. We present a simple algorithm which modifies the (Mani‐) Wordle idea with scan‐line based techniques to allow a better placement. We give an introduction to common placement techniques from different fields and compare our method to these techniques w.r.t. euclidean displacement, changes in orthogonal ordering as well as shape and size preservation. Especially in dense scenarios our method preserves the overall shape better than known techniques and allows a good trade‐off between the other measures. Applications on real world data are given and discussed. | false | false | [
"Hendrik Strobelt",
"Marc Spicker",
"Andreas Stoffel",
"Daniel A. Keim",
"Oliver Deussen"
] | [] | [] | [] |
EuroVis | 2,012 | Scalable Detection of Spatiotemporal Encounters in Historical Movement Data | 10.1111/j.1467-8659.2012.03084.x | The widespread adoption of location‐aware devices is resulting in the generation of large amounts of spatiotemporal movement data, collected and stored in digital repositories. This forms a fertile ground for domain experts and scientists to analyze such historical data and discover interesting movement behavioral patterns. Experts in many domains, such as transportation, logistics and retail, are interested in detecting and understanding movement patterns and behavior of objects in relation to each other. Their insights can point to optimization potential and reveal deviations from planned behavior. In this paper, we focus on the detection of the encounter patterns as one possible type in movement behavior. These patterns refer to objects being close to one another in terms of space and time. We define scalability as a core requirement when dealing with historical movement data, in order to allow the domain expert to set parameters of the encounter detection algorithm. Our approach leverages a designated data structure and requires only a single pass over chronological data, thus resulting in highly scalable and fast technique to detect encounters. Consequently, users are able to explore their data by interactively specifying the spatial and temporal windows that define encounters. We evaluate our proposed method as a function of its input parameters and data size. We instantiate the proposed method on urban public transportation data, where we found a large number of encounters. We show that single encounters emerge into higher level patterns that are of particular interest and value to the domain. | false | false | [
"Peter Bak",
"Mattias Marder",
"Sivan Harary",
"Avi Yaeli",
"Harold J. Ship"
] | [] | [] | [] |
EuroVis | 2,012 | Semantic Wordification of Document Collections | 10.1111/j.1467-8659.2012.03107.x | Word clouds have become one of the most widely accepted visual resources for document analysis and visualization, motivating the development of several methods for building layouts of keywords extracted from textual data. Existing methods are effective to demonstrate content, but are not capable of preserving semantic relationships among keywords while still linking the word cloud to the underlying document groups that generated them. Such representation is highly desirable for exploratory analysis of document collections. In this paper we present a novel approach to build document clouds, named ProjCloud that aim at solving both semantical layouts and linking with document sets. ProjCloud generates a semantically consistent layout from a set of documents. Through a multidimensional projection, it is possible to visualize the neighborhood relationship between highly related documents and their corresponding word clouds simultaneously. Additionally, we propose a new algorithm for building word clouds inside polygons, which employs spectral sorting to maintain the semantic relationship among words. The effectiveness and flexibility of our methodology is confirmed when comparisons are made to existing methods. The technique automatically constructs projection based layouts the user may choose to examine in the form of the point clouds or corresponding word clouds, allowing a high degree of control over the exploratory process. | false | false | [
"Fernando Vieira Paulovich",
"Franklina Maria Bragion Toledo",
"Guilherme P. Telles",
"Rosane Minghim",
"Luis Gustavo Nonato"
] | [] | [] | [] |
EuroVis | 2,012 | Semi-Supervised Dimensionality Reduction based on Partial Least Squares for Visual Analysis of High Dimensional Data | 10.1111/j.1467-8659.2012.03126.x | Dimensionality reduction is employed for visual data analysis as a way to obtaining reduced spaces for high dimensional data or to mapping data directly into 2D or 3D spaces. Although techniques have evolved to improve data segregation on reduced or visual spaces, they have limited capabilities for adjusting the results according to user's knowledge. In this paper, we propose a novel approach to handling both dimensionality reduction and visualization of high dimensional data, taking into account user's input. It employs Partial Least Squares (PLS), a statistical tool to perform retrieval of latent spaces focusing on the discriminability of the data. The method employs a training set for building a highly precise model that can then be applied to a much larger data set very effectively. The reduced data set can be exhibited using various existing visualization techniques. The training data is important to code user's knowledge into the loop. However, this work also devises a strategy for calculating PLS reduced spaces when no training data is available. The approach produces increasingly precise visual mappings as the user feeds back his or her knowledge and is capable of working with small and unbalanced training sets. | false | false | [
"Jose Gustavo Paiva",
"William Robson Schwartz",
"Hélio Pedrini",
"Rosane Minghim"
] | [] | [] | [] |
EuroVis | 2,012 | StratomeX: Visual Analysis of Large-Scale Heterogeneous Genomics Data for Cancer Subtype Characterization | 10.1111/j.1467-8659.2012.03110.x | Identification and characterization of cancer subtypes are important areas of research that are based on the integrated analysis of multiple heterogeneous genomics datasets. Since there are no tools supporting this process, much of this work is done using ad‐hoc scripts and static plots, which is inefficient and limits visual exploration of the data. To address this, we have developed StratomeX, an integrative visualization tool that allows investigators to explore the relationships of candidate subtypes across multiple genomic data types such as gene expression, DNA methylation, or copy number data. StratomeX represents datasets as columns and subtypes as bricks in these columns. Ribbons between the columns connect bricks to show subtype relationships across datasets. Drill‐down features enable detailed exploration. StratomeX provides insights into the functional and clinical implications of candidate subtypes by employing small multiples, which allow investigators to assess the effect of subtypes on molecular pathways or outcomes such as patient survival. As the configuration of viewing parameters in such a multi‐dataset, multi‐view scenario is complex, we propose a meta visualization and configuration interface for dataset dependencies and data‐view relationships. StratomeX is developed in close collaboration with domain experts. We describe case studies that illustrate how investigators used the tool to explore subtypes in large datasets and demonstrate how they efficiently replicated findings from the literature and gained new insights into the data. | false | false | [
"Alexander Lex",
"Marc Streit",
"Hans-Jörg Schulz",
"Christian Partl",
"Dieter Schmalstieg",
"Peter J. Park",
"Nils Gehlenborg"
] | [
"HM"
] | [] | [] |
EuroVis | 2,012 | The World's Languages Explorer: Visual Analysis of Language Features in Genealogical and Areal Contexts | 10.1111/j.1467-8659.2012.03086.x | This paper presents a novel Visual Analytics approach that helps linguistic researchers to explore the world's languages with respect to several important tasks: (1) The comparison of manually and automatically extracted language features across languages and within the context of language genealogy, (2) the exploration of interrelations among several of such features as well as their homogeneity and heterogeneity within subtrees of the language genealogy, and (3) the exploration of genealogical and areal influences on the features. We introduce the World's Languages Explorer, which provides the required functionalities in one single Visual Analytics environment. Contributions are made for different parts of the system: We introduce an extended Sunburst visualization whose so‐called feature‐rings allow for a cross‐comparison of a large number of features at once, within the hierarchical context of the language genealogy. We suggest a mapping of homogeneity measures to all levels of the hierarchy. In addition, we suggest an integration of information from the areal data space into the hierarchical data space. With our approach we bring Visual Analytics research to a new application field, namely Historical Comparative Linguistics, and Linguistic and Areal Typology. Finally, we provide evidence of the good performance of our system in this area through two application case studies conducted by domain experts. | false | false | [
"Christian Rohrdantz",
"Michael Hund",
"Thomas Mayer 0001",
"Bernhard Wälchli",
"Daniel A. Keim"
] | [] | [] | [] |
EuroVis | 2,012 | Tracing Tuples Across Dimensions: A Comparison of Scatterplots and Parallel Coordinate Plots | 10.1111/j.1467-8659.2012.03129.x | One of the fundamental tasks for analytic activity is retrieving (i.e., reading) the value of a particular quantity in an information visualization. However, few previous studies have compared user performance in such value retrieval tasks for different visualizations. We present an experimental comparison of user performance (time and error distance) across four multivariate data visualizations. Three variants of scatterplot (SCP) visualizations, namely SCPs with common vertical axes (SCP‐common), SCPs with a staircase layout (SCP‐staircase), and SCPs with rotated axes between neighboring cells (SCP‐rotated), and a baseline parallel coordinate plots (PCP) were compared. Results show that the baseline PCP is better than SCP‐rotated and SCP‐staircase under all conditions, while the difference between SCP‐common and PCP depends on the dimensionality and density of the dataset. PCP shows advantages over SCP‐common when the dimensionality and density of the dataset are low, but SCP‐common eventually outperforms PCP as data dimensionality and density increase. The results suggest guidelines for the use of SCPs and PCPs that can benefit future researchers and practitioners. | false | false | [
"Xiaole Kuang",
"Haimo Zhang",
"Shengdong Zhao",
"Michael J. McGuffin"
] | [] | [] | [] |
EuroVis | 2,012 | Travel-Route-Centered Metro Map Layout and Annotation | 10.1111/j.1467-8659.2012.03085.x | When providing travel guides for a specific route in a metro network, we often place the route around the center of the map and annotate stations on the route with thumbnail photographs. Nonetheless, existing methods do not offer an effective means of customizing the network layout in order to accommodate such large annotation labels while preserving its planar embedding. This paper presents a new approach for designing the metro map layout in order to annotate stations on a specific travel route with large annotation labels. Our idea is to elongate the travel route to be straight along the centerline of the map so that we can systematically annotate such stations with external labels. This is accomplished by extending the conventional mixed‐integer programming technique for computing octilinear layouts where orientations inherent to the metro line segments are plausibly rearranged. The stations are then connected with external labels through leaders while minimizing intersections with metro lines for enhancing visual clarity. We present several design examples of metro maps and user studies to demonstrate that the proposed aesthetic criteria successfully direct viewers’ attention to specific travel routes. | false | false | [
"Hsiang-Yun Wu",
"Shigeo Takahashi",
"Chun-Cheng Lin",
"Hsu-Chun Yen"
] | [] | [] | [] |
EuroVis | 2,012 | Using Signposts for Navigation in Large Graphs | 10.1111/j.1467-8659.2012.03091.x | In this paper we present a new Focus & Context technique for the exploration of large, abstract graphs. Most Focus & Context techniques present context in a visual way. In contrast, our technique uses a symbolic representation: while the focus is a set of visible nodes, labelled signposts provide cues for the context — off‐screen regions of the graph — and indicate the direction of the shortest path linking the visible nodes to these regions. We show how the regions are defined and how they are selected dynamically, depending on the visible nodes. To define the set of visible nodes we use an approach developed by van Ham and Perer that dynamically extracts a subgraph based on an initial focal node and a degree‐of‐interest function. This approach is extended to support multiple focal nodes. With the symbolic visualization, potentially interesting regions of a graph may be represented with a very small visual footprint. We conclude the paper with an initial user study to evaluate the effectiveness of the signposts for navigation tasks. | false | false | [
"Thorsten May",
"Martin Steiger",
"James Davey",
"Jörn Kohlhammer"
] | [] | [] | [] |
EuroVis | 2,012 | Vismon: Facilitating Analysis of Trade-Offs, Uncertainty, and Sensitivity In Fisheries Management Decision Making | 10.1111/j.1467-8659.2012.03116.x | In this design study, we present an analysis and abstraction of the data and task in the domain of fisheries management, and the design and implementation of the Vismon tool to address the identified requirements. Vismon was designed to support sophisticated data analysis of simulation results by managers who are highly knowledgeable about the fisheries domain but not experts in simulation software and statistical data analysis. The previous workflow required the scientists who built the models to spearhead the analysis process. The features of Vismon include sensitivity analysis, comprehensive and global trade‐offs analysis, and a staged approach to the visualization of the uncertainty of the underlying simulation model. The tool was iteratively refined through a multi‐year engagement with fisheries scientists with a two‐phase approach, where an initial diverging experimentation phase to test many alternatives was followed by a converging phase where the set of multiple linked views that proved effective were integrated together in a useable way. Several fisheries scientists have used Vismon to communicate with policy makers, and it is scheduled for deployment to policy makers in Alaska. | false | false | [
"Maryam Booshehrian",
"Torsten Möller",
"Randall M. Peterman",
"Tamara Munzner"
] | [
"HM"
] | [] | [] |
EuroVis | 2,012 | Visualization of 4D Blood-Flow Fields by Spatiotemporal Hierarchical Clustering | 10.1111/j.1467-8659.2012.03099.x | Advancements in the acquisition and modeling of flow fields result in unsteady volumetric flow fields of unprecedented quality. An important example is found in the analysis of unsteady blood‐flow data. Preclinical research strives for a better understanding of correlations between the hemodynamics and the progression of cardiovascular diseases. Modern‐day computer models and MRI acquisition provide time‐resolved volumetric blood‐flow velocity fields. Unfortunately, these fields often remain unexplored, as high‐dimensional data are difficult to conceive. We present a spatiotemporal, i.e., four‐dimensional, hierarchical clustering, yielding a sparse representation of the velocity data. The clustering results underpin an illustrative visualization approach, facilitating visual analysis. The hierarchy allows an intuitive level‐of‐detail selection, largely retaining important flow patterns. The clustering employs dissimilarity measures to construct the hierarchy. We have adapted two existing measures for steady vector fields for use in the spacetime domain. Because of the inherent computational complexity of the multidimensional clustering, we introduce a coarse hierarchical clustering approach, which closely approximates the full hierarchy generation, and considerably improves the performance. The resulting clusters are visualized by representative patharrows, in combination with an illustrative anatomical context. We present various seeding approaches and visualization styles, providing sparse overviews of the unsteady behavior of volumetric flow fields. | false | false | [
"Roy van Pelt",
"S. S. A. M. Jacobs",
"Bart M. ter Haar Romeny",
"Anna Vilanova"
] | [] | [] | [] |
EuroVis | 2,012 | Visualization of Advection-Diffusion in Unsteady Fluid Flow | 10.1111/j.1467-8659.2012.03103.x | Advection has been the standard transport mechanism in flow visualization. Diffusion, in contrast, has not been considered important in visual flow field analysis so far, although it is inherent to many physical processes. We present a novel technique that allows for interactive 3D visualization of both advection and diffusion in unsteady fluid flow. We extend texture‐based flow visualization, which is advection‐oriented, by diffusion. Our finite volume approach based on WENO (weighted essentially non‐oscillatory) reconstruction is well parallelizable and features low numerical diffusion at interactive rates. Our scheme contributes to three different applications: (a) high‐quality dye advection at low numerical diffusion, (b) physically‐based dye advection accounting for diffusivity of virtual media, and (c) visualization of advection‐diffusion fluxes in physical media where the velocity field is accompanied by a concentration field. Interactive rendering of the virtual dye is accomplished by ray casting. We apply our GPU implementation to CFD examples of thermal convection and evaporation phenomena. | false | false | [
"Grzegorz Karol Karch",
"Filip Sadlo",
"Daniel Weiskopf",
"Claus-Dieter Munz",
"Thomas Ertl"
] | [] | [] | [] |
EuroVis | 2,012 | Visualization of Global Correlation Structures in Uncertain 2D Scalar Fields | 10.1111/j.1467-8659.2012.03095.x | Visualizing correlations, i.e., the tendency of uncertain data values at different spatial positions to change contrarily or according to each other, allows inferring on the possible variations of structures in the data. Visualizing global correlation structures, however, is extremely challenging, since it is not clear how the visualization of complicated long‐range dependencies can be integrated into standard visualizations of spatial data. Furthermore, storing correlation information imposes a memory requirement that is quadratic in the number of spatial sample positions. This paper presents a novel approach for visualizing both positive and inverse global correlation structures in uncertain 2D scalar fields, where the uncertainty is modeled via a multivariate Gaussian distribution. We introduce a new measure for the degree of dependency of a random variable on its local and global surroundings, and we propose a spatial clustering approach based on this measure to classify regions of a particular correlation strength. The clustering performs a correlation filtering, which results in a representation that is only linear in the number of spatial sample points. Via cluster coloring the correlation information can be embedded into visualizations of other statistical quantities, such as the mean and the standard deviation. We finally propose a hierarchical cluster subdivision scheme to further allow for the simultaneous visualization of local and global correlations. | false | false | [
"Tobias Pfaffelmoser",
"Rüdiger Westermann"
] | [] | [] | [] |
EuroVis | 2,012 | Visualizing Motion Data in Virtual Reality: Understanding the Roles of Animation, Interaction, and Static Presentation | 10.1111/j.1467-8659.2012.03114.x | We present a study of interactive virtual reality visualizations of scientific motions as found in biomechanics experiments. Our approach is threefold. First, we define a taxonomy of motion visualizations organized by the method (animation, interaction, or static presentation) used to depict both the spatial and temporal dimensions of the data. Second, we design and implement a set of eight example visualizations suggested by the taxonomy and evaluate their utility in a quantitative user study. Third, together with biomechanics collaborators, we conduct a qualitative evaluation of the eight example visualizations applied to a current study of human spinal kinematics. Results suggest that visualizations in this style that use interactive control for the time dimension of the data are preferable to others. Within this category, quantitative results support the utility of both animated and interactive depictions for space; however, qualitative feedback suggest that animated depictions for space should be avoided in biomechanics applications. | false | false | [
"Dane M. Coffey",
"Fedor Korsakov",
"Marcus Ewert",
"Haleh Hagh-Shenas",
"Lauren Thorson",
"Arin M. Ellingson",
"David J. Nuckley",
"Daniel F. Keefe"
] | [] | [] | [] |
EuroVis | 2,012 | Vortex Analysis in Uncertain Vector Fields | 10.1111/j.1467-8659.2012.03096.x | We present an approach to extract and visualize vortex structures in uncertain vector fields. For this, we generalize the concepts of the most common vortex detectors to uncertain vector fields, namely the λ2‐criterion, Q‐criterion, and the concept of parallel vectors at the example of the method by Sujudi and Haimes. All these methods base on the computation of derivatives of the uncertain vector field which are uncertain fields as well. Since they generally cannot be computed in a closed form, we provide a Monte Carlo algorithm to compute the respective probability distributions. Based on this, uncertain versions of vortex regions and core structures are introduced. We present results of our approach on three real world data sets in order to give a proof of concept. | false | false | [
"Mathias Otto",
"Holger Theisel"
] | [] | [] | [] |
CHI | 2,012 | "I'd never get out of this !?$%# office": redesigning time management for the enterprise | 10.1145/2207676.2208307 | In this paper, we propose to improve time management in the enterprise by providing users interactive visualizations of how they are spending their time. Through an interview study (n=21) in a multi-national corporation, we were able to determine the data available for visualizations and the value of a number of general visualizations of employees' calendar data. We develop implications for design in improving personal time management. | false | false | [
"Casey Dugan",
"Werner Geyer",
"Michael J. Muller",
"Abel N. Valente",
"Katherine James",
"Steve Levy",
"Li-Te Cheng",
"Elizabeth M. Daly",
"Beth Brownholtz"
] | [] | [] | [] |
CHI | 2,012 | A spatiotemporal visualization approach for the analysis of gameplay data | 10.1145/2207676.2208558 | Contemporary video games are highly complex systems with many interacting variables. To make sure that a game provides a satisfying experience, a meaningful analysis of gameplay data is crucial, particularly because the quality of a game directly relates to the experience a user gains from playing it. Automatic instrumentation techniques are increasingly used to record data during playtests. However, the evaluation of the data requires strong analytical skills and experience. The visualization of such gameplay data is essentially an information visualization problem, where a large number of variables have to be displayed in a comprehensible way in order to be able to make global judgments. This paper presents a visualization tool to assist the analytical process. It visualizes the game space as a set of nodes which players visit over the course of a game and is also suitable to observe time-dependent information, such as player distribution. Our tool is not tailored to a specific type of genre. To show the flexibility of our approach we use two different kinds of games as case studies. | false | false | [
"Günter Wallner",
"Simone Kriglstein"
] | [] | [] | [] |
CHI | 2,012 | Analysis within and between graphs: observed user strategies in immunobiology visualization | 10.1145/2207676.2208291 | We present an analysis of two user strategies in interactive data analysis, based on an observational study of four researchers in the immunology domain. Screen captures, video records, interviews, and verbal protocols are used to analyze common procedures in this type of visual data analysis, as well as how these procedures differ among these users. Our findings present a case where skilled users can approach a similar problem with diverging analysis strategies. In the group we observed, strategies fell within two broad categories: within-graph analysis, in which a user generates a few graph layouts and interacts heavily within them, and between-graph analysis, in which a user generates a series of graphs and switches between them in sequence. Differences in strategies lead to distinct interaction patterns, and are likely to be best supported by different interface designs. We characterize these observed strategies and discuss their implications for scientific visualization design and evaluation. | false | false | [
"Caroline Ziemkiewicz",
"Steven R. Gomez",
"David H. Laidlaw"
] | [] | [] | [] |
CHI | 2,012 | Annotating BI visualization dashboards: needs & challenges | 10.1145/2207676.2208288 | Annotations have been identified as an important aid in analysis record-keeping and recently data discovery. In this paper we discuss the use of annotations on visualization dashboards, with a special focus on business intelligence (BI) analysis. In-depth interviews with experts lead to new annotation needs for multi-chart visualization systems, on which we based the design of a dashboard prototype that supports data and context aware annotations. We focus particularly on novel annotation aspects, such as multi-target annotations, annotation transparency across charts and data dimension levels, as well as annotation properties such as lifetime and validity. Moreover, our prototype is built on a data layer shared among different data-sources and BI applications, allowing cross application annotations. We discuss challenges in supporting context aware annotations in dashboards and other visualizations, such as dealing with changing annotated data, and provide design solutions. Finally we report reactions and recommendations from a different set of expert users. | false | false | [
"Micheline Elias",
"Anastasia Bezerianos"
] | [] | [] | [] |
CHI | 2,012 | Comparing averages in time series data | 10.1145/2207676.2208556 | Visualizations often seek to aid viewers in assessing the big picture in the data, that is, to make judgments about aggregate properties of the data. In this paper, we present an empirical study of a representative aggregate judgment task: finding regions of maximum average in a series. We show how a theory of perceptual averaging suggests a visual design other than the typically-used line graph. We describe an experiment that assesses participants' ability to estimate averages and make judgments based on these averages. The experiment confirms that this color encoding significantly outperforms the standard practice. The experiment also provides evidence for a perceptual averaging theory. | false | false | [
"Michael Correll",
"Danielle Albers",
"Steven Franconeri",
"Michael Gleicher"
] | [] | [] | [] |
CHI | 2,012 | Delta: a tool for representing and comparing workflows | 10.1145/2207676.2208549 | Tutorials and sample workflows for complicated, feature-rich software packages are widely available online. As a result users must differentiate between workflows to choose the most suitable one for their task. We present Delta, an interactive workflow visualization and comparison tool that helps users identify the tradeoffs between workflows. We conducted an initial study to identify the set of attributes users attend to when comparing workflows, finding that they consider result quality, their knowledge of commands, and the efficiency of the workflow. We then designed Delta to surface these attributes at three granularities: a high-level, clustered view; an intermediate-level list view that contains workflow summaries; and a low-level detail view that allows users to compare two individual workflows. Finally, we conducted an evaluation of Delta on a small corpus of 30 workflows and found that the intermediate list view provided the best information density. We conclude with thoughts on how such a workflow comparison system could be scaled up to larger corpora in the future. | false | false | [
"Nicholas Kong",
"Tovi Grossman",
"Björn Hartmann",
"Maneesh Agrawala",
"George W. Fitzmaurice"
] | [] | [] | [] |
CHI | 2,012 | Digital pen and paper practices in observational research | 10.1145/2207676.2208590 | Researchers from many disciplines are taking advantage of increasingly inexpensive digital video to capture extensive records of human activity in real-world settings. The ability to record and share such data has created a critical moment in the practice and scope of behavioral research. While recent work is beginning to develop techniques for visualizing and interacting with integrated multimodal information collected during field research, navigating and analyzing these large datasets remains challenging and tools are especially needed to support the early stages of data exploration. In this paper we describe digital pen and paper practices in observational research and their integration with ChronoViz, a tool for annotating, visualizing, and analyzing multimodal data. The goal is to better support researchers both in the field, while collecting data, and later in the lab, during analysis. We document the co-evolution of notetaking practices and system features as 28 participants used the tool during an 18-month deployment. | false | false | [
"Nadir Weibel",
"Adam Fouse",
"Colleen Emmenegger",
"Whitney Friedman",
"Edwin L. Hutchins",
"James D. Hollan"
] | [] | [] | [] |
CHI | 2,012 | EEG analysis of implicit human visual perception | 10.1145/2207676.2207746 | Image Based Rendering (IBR) allows interactive scene exploration from images alone. However, despite considerable development in the area, one of the main obstacles to better quality and more realistic visualizations is the occurrence of visually disagreeable artifacts. In this paper we present a methodology to map out the perception of IBR-typical artifacts. This work presents an alternative to traditional image and video quality evaluation methods by using an EEG device to determine the implicit visual processes in the human brain. Our work demonstrates the distinct differences in the perception of different types of visual artifacts and the implications of these differences. | false | false | [
"Maryam Mustafa",
"Lea Lindemann",
"Marcus A. Magnor"
] | [] | [] | [] |
CHI | 2,012 | Gaze-augmented think-aloud as an aid to learning | 10.1145/2207676.2208710 | The use of recorded eye movements, or scanpaths, has been demonstrated as an effective visualization for feed-forward visual search training, instruction, and stimulated retrospective think-aloud usability testing. In this paper we show that creation of a scripted or recorded video of an expert's think-aloud session augmented by an animation of their scanpaths can result in an effective aid for learners of visual search. Because the creation of such a video is relatively easy, the benefits-to-cost ratio may potentially be substantial, especially in settings where learned visual scanning strategies are indicators of expertise. We suggest that two such examples are examinations of Chest X-Rays and histological slides. Results are presented where straightforward construction of an instruction video provides measurable benefit to novice as well as experienced learners in the latter context. | false | false | [
"Sarah A. Vitak",
"John E. Ingram",
"Andrew T. Duchowski",
"Steven Ellis",
"Anand K. Gramopadhye"
] | [] | [] | [] |
CHI | 2,012 | GraphTrail: analyzing large multivariate, heterogeneous networks while supporting exploration history | 10.1145/2207676.2208293 | Exploring large network datasets, such as scientific collaboration networks, is challenging because they often contain a large number of nodes and edges in several types and with multiple attributes. Analyses of such networks are often long and complex, and may require several sessions by multiple users. Therefore, it is often difficult for users to recall their own exploration history or share it with others. We introduce GraphTrail, an interactive visualization for analyzing networks through exploration of node and edge aggregates that captures users' interactions and integrates this history directly in the exploration workspace. To facilitate large network analysis, GraphTrail integrates aggregation with familiar charts, drag-and-drop interaction on a canvas, and a novel pivoting mechanism for transitioning between aggregates. Through a three-month field study with a team of archeologists and a qualitative lab study with ten users, we demonstrate the effectiveness of our design and the benefits of integrated exploration history, including analysis comprehension, insight discovery, and exploration recall. | false | false | [
"Cody Dunne",
"Nathalie Henry Riche",
"Bongshin Lee",
"Ronald A. Metoyer",
"George G. Robertson"
] | [] | [] | [] |
CHI | 2,012 | Interactive visualization for low literacy users: from lessons learnt to design | 10.1145/2207676.2208565 | This paper aims to address the problems low literacy (LL) users face when searching for information online. The first part of this paper summarizes the problems that LL user's face, and establishes a set of design principles for interfaces suitable for LL users. This is followed by a description of how these design principles are mapped to a novel interface for interactive data retrieval. The interface was realized into a working system and evaluated against a traditional web interface for both high literacy (HL) and LL users. The suitability of the designs was analyzed using performance data, subjective feedback and an observational analysis. The findings from the study suggest that LL users perform better and prefer the proposed designs over a traditional web interface. | false | false | [
"Neesha Kodagoda",
"B. L. William Wong",
"Chris Rooney",
"Nawaz Khan"
] | [] | [] | [] |
CHI | 2,012 | Interpretation and trust: designing model-driven visualizations for text analysis | 10.1145/2207676.2207738 | Statistical topic models can help analysts discover patterns in large text corpora by identifying recurring sets of words and enabling exploration by topical concepts. However, understanding and validating the output of these models can itself be a challenging analysis task. In this paper, we offer two design considerations - interpretation and trust - for designing visualizations based on data-driven models. Interpretation refers to the facility with which an analyst makes inferences about the data through the lens of a model abstraction. Trust refers to the actual and perceived accuracy of an analyst's inferences. These considerations derive from our experiences developing the Stanford Dissertation Browser, a tool for exploring over 9,000 Ph.D. theses by topical similarity, and a subsequent review of existing literature. We contribute a novel similarity measure for text collections based on a notion of "word-borrowing" that arose from an iterative design process. Based on our experiences and a literature review, we distill a set of design recommendations and describe how they promote interpretable and trustworthy visual analysis tools. | false | false | [
"Jason Chuang",
"Daniel Ramage",
"Christopher D. Manning",
"Jeffrey Heer"
] | [] | [] | [] |
CHI | 2,012 | JigsawMap: connecting the past to the future by mapping historical textual cadasters | 10.1145/2207676.2207740 | In this paper, we present an interactive visualization tool, JigsawMap, for visualizing and mapping historical textual cadasters. A cadaster is an official register that records land properties (e.g., location, ownership, value and size) for land valuation and taxation. Such mapping of old and new cadasters can help historians understand the social/economic background of changes in land uses or ownership. With JigsawMap, historians can continue mapping older or newer cadasters. In this way, JigsawMap can connect the past land survey results to today and to the future. We conducted usability studies and long term case studies to evaluate JigsawMap, and received positive responses. As well as summarizing the evaluation results, we also present design guidelines for participatory design projects with historians. | false | false | [
"Hyungmin Lee",
"Sooyun Lee",
"Namwook Kim",
"Jinwook Seo"
] | [] | [] | [] |
CHI | 2,012 | Legible, are you sure?: an experimentation-based typographical design in safety-critical context | 10.1145/2207676.2208387 | Designing Safety-critical interfaces entails proving the safety and operational usability of each component. Largely taken for granted in everyday interface design, the typographical component, through its legibility and aesthetics, weighs heavily on the ubiquitous reading task at the heart of most visualizations and interactions. In this paper, we present a research project whose goal is the creation of a new typeface to display textual information on future aircraft interfaces. After an initial task analysis leading to the definition of specific needs, requirements and design principles, the design constantly evolves from an iterative cycle of design and experimentation. We present three experiments (laboratory and cockpit) used mainly to validate initial choices and fine-tune font properties. Results confirm the importance of rigorously testing the typographical component as a part of text output evaluation in interactive systems. | false | false | [
"Jean-Luc Vinot",
"Sylvie Athènes"
] | [] | [] | [] |
CHI | 2,012 | LightGuide: projected visualizations for hand movement guidance | 10.1145/2207676.2207702 | LightGuide is a system that explores a new approach to gesture guidance where we project guidance hints directly on a user's body. These projected hints guide the user in completing the desired motion with their body part which is particularly useful for performing movements that require accuracy and proper technique, such as during exercise or physical therapy. Our proof-of-concept implementation consists of a single low-cost depth camera and projector and we present four novel interaction techniques that are focused on guiding a user's hand in mid-air. Our visualizations are designed to incorporate both feedback and feedforward cues to help guide users through a range of movements. We quantify the performance of LightGuide in a user study comparing each of our on-body visualizations to hand animation videos on a computer display in both time and accuracy. Exceeding our expectations, participants performed movements with an average error of 21.6mm, nearly 85% more accurately than when guided by video. | false | false | [
"Rajinder Sodhi",
"Hrvoje Benko",
"Andrew D. Wilson"
] | [] | [] | [] |
CHI | 2,012 | MirageTable: freehand interaction on a projected augmented reality tabletop | 10.1145/2207676.2207704 | Instrumented with a single depth camera, a stereoscopic projector, and a curved screen, MirageTable is an interactive system designed to merge real and virtual worlds into a single spatially registered experience on top of a table. Our depth camera tracks the user's eyes and performs a real-time capture of both the shape and the appearance of any object placed in front of the camera (including user's body and hands). This real-time capture enables perspective stereoscopic 3D visualizations to a single user that account for deformations caused by physical objects on the table. In addition, the user can interact with virtual objects through physically-realistic freehand actions without any gloves, trackers, or instruments. We illustrate these unique capabilities through three application examples: virtual 3D model creation, interactive gaming with real and virtual objects, and a 3D teleconferencing experience that not only presents a 3D view of a remote person, but also a seamless 3D shared task space. We also evaluated the user's perception of projected 3D objects in our system, which confirmed that the users can correctly perceive such objects even when they are projected over different background colors and geometries (e.g., gaps, drops). | false | false | [
"Hrvoje Benko",
"Ricardo Jota",
"Andrew Wilson"
] | [] | [] | [] |
CHI | 2,012 | Observational and experimental investigation of typing behaviour using virtual keyboards for mobile devices | 10.1145/2207676.2208658 | With the rise of current smartphones, virtual keyboards for touchscreens became the dominant mobile text entry technique. We developed a typing game that records how users touch on the standard Android keyboard to investigate users' typing behaviour. 47,770,625 keystrokes from 72,945 installations have been collected by publishing the game. By visualizing the touch distribution we identified a systematic skew and derived a function that compensates this skew by shifting touch events. By updating the game we conduct an experiment that investigates the effect of shifting touch events, changing the keys' labels, and visualizing the touched position. Results based on 6,603,659 keystrokes and 13,013 installations show that visualizing the touched positions using a simple dot decreases the error rate of the Android keyboard by 18.3% but also decreases the speed by 5.2% with no positive effect on learnability. The Android keyboard outperforms the control condition but the constructed shift function further improves the performance by 2.2% and decreases the error rate by 9.1%. We argue that the shift function can improve existing keyboards at no costs. | false | false | [
"Niels Henze",
"Enrico Rukzio",
"Susanne Boll"
] | [] | [] | [] |
CHI | 2,012 | Omnipedia: bridging the wikipedia language gap | 10.1145/2207676.2208553 | We present Omnipedia, a system that allows Wikipedia readers to gain insight from up to 25 language editions of Wikipedia simultaneously. Omnipedia highlights the similarities and differences that exist among Wikipedia language editions, and makes salient information that is unique to each language as well as that which is shared more widely. We detail solutions to numerous front-end and algorithmic challenges inherent to providing users with a multilingual Wikipedia experience. These include visualizing content in a language-neutral way and aligning data in the face of diverse information organization strategies. We present a study of Omnipedia that characterizes how people interact with information using a multilingual lens. We found that users actively sought information exclusive to unfamiliar language editions and strategically compared how language editions defined concepts. Finally, we briefly discuss how Omnipedia generalizes to other domains facing language barriers. | false | false | [
"Patti Bao",
"Brent J. Hecht",
"Samuel Carton",
"Mahmood Quaderi",
"Michael S. Horn",
"Darren Gergle"
] | [] | [] | [] |
CHI | 2,012 | Semantic interaction for visual text analytics | 10.1145/2207676.2207741 | Visual analytics emphasizes sensemaking of large, complex datasets through interactively exploring visualizations generated by statistical models. For example, dimensionality reduction methods use various similarity metrics to visualize textual document collections in a spatial metaphor, where similarities between documents are approximately represented through their relative spatial distances to each other in a 2D layout. This metaphor is designed to mimic analysts' mental models of the document collection and support their analytic processes, such as clustering similar documents together. However, in current methods, users must interact with such visualizations using controls external to the visual metaphor, such as sliders, menus, or text fields, to directly control underlying model parameters that they do not understand and that do not relate to their analytic process occurring within the visual metaphor. In this paper, we present the opportunity for a new design space for visual analytic interaction, called semantic interaction, which seeks to enable analysts to spatially interact with such models directly within the visual metaphor using interactions that derive from their analytic process, such as searching, highlighting, annotating, and repositioning documents. Further, we demonstrate how semantic interactions can be implemented using machine learning techniques in a visual analytic tool, called ForceSPIRE, for interactive analysis of textual data within a spatial visualization. Analysts can express their expert domain knowledge about the documents by simply moving them, which guides the underlying model to improve the overall layout, taking the user's feedback into account. | false | false | [
"Alex Endert",
"Patrick Fiaux",
"Chris North 0001"
] | [] | [] | [] |
CHI | 2,012 | Supporting improvisation work in inter-organizational crisis management | 10.1145/2207676.2208617 | Improvisation is necessary when planned decision-making as the main managerial activity does not fit the conditions the practice provides. In these cases, information technology should not just automate planned and structured decisions, but support improvisational practice. In this contribution we present an empirical study about the improvisation work in scenarios of medium to large power outages in Germany. Our focus is on inter-organizational cooperation practices, thus we examined the cooperation of fire departments, police, public administration, electricity infrastructure operators and citizens. Our empirical material allows to describe reasons and conditions for improvisation. Our resulting recommendations address the support of aggregation and visualization of information, a necessary individualization of information compositions, options for collaborative situation assessment, requirements for informal and formal communication, and accessibility of information resources. | false | false | [
"Benedikt Ley",
"Volkmar Pipek",
"Christian Reuter 0001",
"Torben Wiedenhoefer"
] | [] | [] | [] |
CHI | 2,012 | Tangible remote controllers for wall-size displays | 10.1145/2207676.2208691 | We explore the use of customizable tangible remote controllers for interacting with wall-size displays. Such controllers are especially suited to visual exploration tasks where users need to move to see details of complex visualizations. In addition, we conducted a controlled user study suggesting that tangibles make it easier for users to focus on the visual display while they interact. We explain how to build such controllers using off-the-shelf touch tablets and describe a sample application that supports multiple dynamic queries. | false | false | [
"Yvonne Jansen",
"Pierre Dragicevic",
"Jean-Daniel Fekete"
] | [] | [] | [] |
CHI | 2,012 | The bohemian bookshelf: supporting serendipitous book discoveries through information visualization | 10.1145/2207676.2208607 | Serendipity, a trigger of exciting yet unexpected discoveries, is an important but comparatively neglected factor in information seeking, research, and ideation. We suggest that serendipity can be facilitated through visualization. To explore this, we introduce the Bohemian Bookshelf, which aims to support serendipitous discoveries in the context of digital book collections. The Bohemian Bookshelf consists of five interlinked visualizations each offering a unique overview of the collection. It aims at encouraging serendipity by (1) offering multiple visual access points to the collection, (2) highlighting adjacencies between books, (3) providing flexible visual pathways for exploring the collection, (4) enticing curiosity through abstract, metaphorical, and visually distinct representations of books, and (5) enabling a playful approach to information exploration. A deployment at a library revealed that visitors embraced this approach of utilizing visualization to support open-ended explorations and serendipitous discoveries. This encourages future explorations into promoting serendipity through information visualization. | false | false | [
"Alice Thudt",
"Uta Hinrichs",
"Sheelagh Carpendale"
] | [] | [] | [] |
CHI | 2,012 | The case of the missed icon: change blindness on mobile devices | 10.1145/2207676.2208606 | Insights into human visual attention have benefited many areas of computing, but perhaps most significantly visualisation and UI design [3]. With the proliferation of mobile devices capable of supporting significantly complex applications on small screens, demands on mobile UI design and the user's visual system are becoming greater. In this paper, we report results from an empirical study of human visual attention, specifically the Change Blindness phenomenon, on handheld mobile devices and its impact on mobile UI design. It is arguable that due to the small size of the screen - unlike a typical computer monitor - a greater visual coverage of the mobile device is possible, and that these phenomena may occur less frequently during the use of the device, or even that they may not occur at all. Our study shows otherwise. We tested for Change Blindness (CB) and Inattentional Blindness (IB) in a single-modal, mobile context and attempted to establish factors in the application interface design that induce and/or reduce their occurrences. The results show that both CB and IB can and do occur while using mobile devices. The results also suggest that the number of separate attendable items on-screen is directly proportional to rates of CB. Newly inserted objects were correctly identified more often than changes applied to existing on-screen objects. These results suggest that it is important for mobile UI designers to take these aspects of visual attention into account when designing mobile applications that attempt to deliver information through visual changes or notifications. | false | false | [
"Thomas Davies",
"Ashweeni Kumar Beeharee"
] | [] | [] | [] |
CHI | 2,012 | Trust me, i'm partially right: incremental visualization lets analysts explore large datasets faster | 10.1145/2207676.2208294 | Queries over large scale (petabyte) data bases often mean waiting overnight for a result to come back. Scale costs time. Such time also means that potential avenues of exploration are ignored because the costs are perceived to be too high to run or even propose them. With sampleAction we have explored whether interaction techniques to present query results running over only incremental samples can be presented as sufficiently trustworthy for analysts both to make closer to real time decisions about their queries and to be more exploratory in their questions of the data. Our work with three teams of analysts suggests that we can indeed accelerate and open up the query process with such incremental visualizations. | false | false | [
"Danyel Fisher",
"Igor O. Popov",
"Steven Mark Drucker",
"m. c. schraefel"
] | [] | [] | [] |
CHI | 2,012 | Understanding the verbal language and structure of end-user descriptions of data visualizations | 10.1145/2207676.2208292 | Tools exist for people to create visualizations with their data; however, they are often designed for programmers or they restrict less technical people to pre-defined templates. This can make creating novel, custom visualizations difficult for the average person. For example, existing tools typically do not support syntax or interaction techniques that are natural to end users. To explore how to support a more natural production of data visualizations by end users, we conducted an exploratory study to illuminate the structure and content of the language employed by end users when describing data visualizations. We present our findings from the study and discuss their design implications for future visualization languages and toolkits. | false | false | [
"Ronald A. Metoyer",
"Bongshin Lee",
"Nathalie Henry Riche",
"Mary Czerwinski"
] | [] | [] | [] |
CHI | 2,012 | V-model: a new innovative model to chronologically visualize narrative clinical texts | 10.1145/2207676.2207739 | Visualizing narrative medical events into a timeline can have positive effects on clinical environments. However, the characteristics of natural language and medical environments make this representation more difficult. This paper explains the obstacles and suggests a solution called the V-Model. The V-Model is a new innovative time model that was developed to represent chronological narrative events in a medical domain. Forty medical students participated in evaluating this model. The experimental results show the new model successfully solved the modeling requirements and had better usability compared to conventional timeline models. All the participants assessed the new timeline as very useful in effectively understanding a patient's history. | false | false | [
"Heekyong Park",
"Jinwook Choi"
] | [] | [] | [] |
CHI | 2,012 | Video summagator: an interface for video summarization and navigation | 10.1145/2207676.2207767 | This paper presents Video Summagator (VS), a volume-based interface for video summarization and navigation. VS models a video as a space-time cube and visualizes the video cube using real-time volume rendering techniques. VS empowers a user to interactively manipulate the video cube. We show that VS can quickly summarize both the static and dynamic video content by visualizing the space-time information in 3D. We demonstrate that VS enables a user to quickly look into the video cube, understand the content, and navigate to the content of interest. | false | false | [
"Cuong Nguyen 0003",
"Yuzhen Niu",
"Feng Liu 0015"
] | [] | [] | [] |
CHI | 2,012 | WebCrystal: understanding and reusing examples in web authoring | 10.1145/2207676.2208740 | Examples have been widely used in the area of web design to help web authors create web pages. However, without actually understanding how an example is constructed, people often have trouble extracting the elements they want and incorporating them into their own design. This paper introduces WebCrystal, a web development tool that helps users understand how a web page is built. WebCrystal contributes novel interaction techniques that let the user quickly access HTML and CSS information by selecting questions regarding how a selected element is designed. It provides answers using a textual description and a customized code snippet that can be copied-and-pasted to recreate the desired properties. WebCrystal also supports combining the styles and structures from multiple elements into the generated code snippet, and provides visualizations on the web page itself to explain layout relationships. Our user study shows that WebCrystal helped both novice and experienced developers complete more tasks successfully using significantly less time. | false | false | [
"Kerry Shih-Ping Chang",
"Brad A. Myers"
] | [] | [] | [] |
Vis | 2,011 | A Scale Space Based Persistence Measure for Critical Points in 2D Scalar fields | 10.1109/TVCG.2011.159 | This paper introduces a novel importance measure for critical points in 2D scalar fields. This measure is based on a combination of the deep structure of the scale space with the well-known concept of homological persistence. We enhance the noise robust persistence measure by implicitly taking the hill-, ridge- and outlier-like spatial extent of maxima and minima into account. This allows for the distinction between different types of extrema based on their persistence at multiple scales. Our importance measure can be computed efficiently in an out-of-core setting. To demonstrate the practical relevance of our method we apply it to a synthetic and a real-world data set and evaluate its performance and scalability. | false | false | [
"Jan Reininghaus",
"Natallia Kotava",
"David Günther",
"Jens Kasten",
"Hans Hagen",
"Ingrid Hotz"
] | [] | [] | [] |
Vis | 2,011 | About the Influence of Illumination Models on Image Comprehension in Direct Volume Rendering | 10.1109/TVCG.2011.161 | In this paper, we present a user study in which we have investigated the influence of seven state-of-the-art volumetric illumination models on the spatial perception of volume rendered images. Within the study, we have compared gradient-based shading with half angle slicing, directional occlusion shading, multidirectional occlusion shading, shadow volume propagation, spherical harmonic lighting as well as dynamic ambient occlusion. To evaluate these models, users had to solve three tasks relying on correct depth as well as size perception. Our motivation for these three tasks was to find relations between the used illumination model, user accuracy and the elapsed time. In an additional task, users had to subjectively judge the output of the tested models. After first reviewing the models and their features, we will introduce the individual tasks and discuss their results. We discovered statistically significant differences in the testing performance of the techniques. Based on these findings, we have analyzed the models and extracted those features which are possibly relevant for the improved spatial comprehension in a relational task. We believe that a combination of these distinctive features could pave the way for a novel illumination model, which would be optimized based on our findings. | false | false | [
"Florian Lindemann",
"Timo Ropinski"
] | [] | [] | [] |
Vis | 2,011 | Adaptive Extraction and Quantification of Geophysical Vortices | 10.1109/TVCG.2011.162 | We consider the problem of extracting discrete two-dimensional vortices from a turbulent flow. In our approach we use a reference model describing the expected physics and geometry of an idealized vortex. The model allows us to derive a novel correlation between the size of the vortex and its strength, measured as the square of its strain minus the square of its vorticity. For vortex detection in real models we use the strength parameter to locate potential vortex cores, then measure the similarity of our ideal analytical vortex and the real vortex core for different strength thresholds. This approach provides a metric for how well a vortex core is modeled by an ideal vortex. Moreover, this provides insight into the problem of choosing the thresholds that identify a vortex. By selecting a target coefficient of determination (i.e., statistical confidence), we determine on a per-vortex basis what threshold of the strength parameter would be required to extract that vortex at the chosen confidence. We validate our approach on real data from a global ocean simulation and derive from it a map of expected vortex strengths over the global ocean. | false | false | [
"Sean Williams",
"Mark R. Petersen",
"Peer-Timo Bremer",
"Matthew Hecht",
"Valerio Pascucci",
"James P. Ahrens",
"Mario Hlawitschka",
"Bernd Hamann"
] | [] | [] | [] |
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