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 |
|---|---|---|---|---|---|---|---|---|---|---|
CHI | 2,011 | 2d touching of 3d stereoscopic objects | 10.1145/1978942.1979142 | Recent developments in the area of touch and display technologies have suggested to combine multi-touch systems and stereoscopic visualization. Stereoscopic perception requires each eye to see a slightly different perspective of the same scene, which results in two distinct projections on the display. Thus, if the user wants to select a 3D stereoscopic object in such a setup, the question arises where she would touch the 2D surface to indicate the selection. A user may apply different strategies, for instance touching the midpoint between the two projections, or touching one of them. In this paper we analyze the relation between the 3D positions of stereoscopically rendered objects and the on-surface touch points, where users touch the surface. We performed an experiment in which we determined the positions of the users' touches for objects, which were displayed with positive, negative or zero parallaxes. We found that users tend to touch between the projections for the two eyes with an offset towards the projection for the dominant eye. Our results give implications for the development of future touch-enabled interfaces, which support 3D stereoscopic visualization. | false | false | [
"Dimitar Valkov",
"Frank Steinicke",
"Gerd Bruder",
"Klaus H. Hinrichs"
] | [] | [] | [] |
CHI | 2,011 | Apolo: making sense of large network data by combining rich user interaction and machine learning | 10.1145/1978942.1978967 | Extracting useful knowledge from large network datasets has become a fundamental challenge in many domains, from scientific literature to social networks and the web. We introduce Apolo, a system that uses a mixed-initiative approach - combining visualization, rich user interaction and machine learning - to guide the user to incrementally and interactively explore large network data and make sense of it. Apolo engages the user in bottom-up sensemaking to gradually build up an understanding over time by starting small, rather than starting big and drilling down. Apolo also helps users find relevant information by specifying exemplars, and then using a machine learning method called Belief Propagation to infer which other nodes may be of interest. We evaluated Apolo with twelve participants in a between-subjects study, with the task being to find relevant new papers to update an existing survey paper. Using expert judges, participants using Apolo found significantly more relevant papers. Subjective feedback of Apolo was also very positive. | false | false | [
"Duen Horng Chau",
"Aniket Kittur",
"Jason I. Hong",
"Christos Faloutsos"
] | [] | [] | [] |
CHI | 2,011 | Augmenting web pages and search results to support credibility assessment | 10.1145/1978942.1979127 | The presence (and, sometimes, prominence) of incorrect and misleading content on the Web can have serious consequences for people who increasingly rely on the internet as their information source for topics such as health, politics, and financial advice. In this paper, we identify and collect several page features (such as popularity among specialized user groups) that are currently difficult or impossible for end users to assess, yet provide valuable signals regarding credibility. We then present visualizations designed to augment search results and Web pages with the most promising of these features. Our lab evaluation finds that our augmented search results are particularly effective at increasing the accuracy of users'" credibility assessments, highlighting the potential of data aggregation and simple interventions to help people make more informed decisions as they search for information online. | false | false | [
"Julia Schwarz",
"Meredith Ringel Morris"
] | [] | [] | [] |
CHI | 2,011 | Cardiogram: visual analytics for automotive engineers | 10.1145/1978942.1979194 | We present Cardiogram, a visual analytics system that supports automotive engineers in debugging masses of traces each consisting of millions of recorded messages from in-car communication networks. With their increasing complexity, ensuring these safety-critical networks to be error-free has become a major task and challenge for automotive engineers. To overcome shortcomings of current analysis tools, Cardiogram combines visualization techniques with a data preprocessing approach to automatically reduce complexity based on engineers' domain knowledge. In this paper, we provide the findings from an exploratory, three-year field study within a large automotive company, studying current practices of engineers, the challenges they meet and the characteristics for integrating novel visual analytics tools into their work practices. We then introduce Cardiogram, discuss how our field analysis influenced our design decisions, and present a qualitative, long-term, in-depth evaluation. Results of this study showed that our participants successfully used Cardiogram to increase the amount of analyzable information, to externalize domain knowledge, and to provide new insights into trace data. Our design approach finally led to the adoption of Cardiogram into engineers' daily practices. | false | false | [
"Michael Sedlmair",
"Petra Isenberg",
"Dominikus Baur",
"Michael Mauerer",
"Christian Pigorsch",
"Andreas Butz"
] | [] | [] | [] |
CHI | 2,011 | CommentSpace: structured support for collaborative visual analysis | 10.1145/1978942.1979407 | Collaborative visual analysis tools can enhance sensemaking by facilitating social interpretation and parallelization of effort. These systems enable distributed exploration and evidence gathering, allowing many users to pool their effort as they discuss and analyze the data. We explore how adding lightweight tag and link structure to comments can aid this analysis process. We present CommentSpace, a collaborative system in which analysts comment on visualizations and websites and then use tags and links to organize findings and identify others'" contributions. In a pair of studies comparing CommentSpace to a system without support for tags and links, we find that a small, fixed vocabulary of tags (question, hypothesis, to-do) and links (evidence-for, evidence-against) helps analysts more consistently and accurately classify evidence and establish common ground. We also find that managing and incentivizing participation is important for analysts to progress from exploratory analysis to deeper analytical tasks. Finally, we demonstrate that tags and links can help teams complete evidence gathering and synthesis tasks and that organizing comments using tags and links improves analytic results. | false | false | [
"Wesley Willett",
"Jeffrey Heer",
"Joseph M. Hellerstein",
"Maneesh Agrawala"
] | [] | [] | [] |
CHI | 2,011 | CueT: human-guided fast and accurate network alarm triage | 10.1145/1978942.1978966 | Network alarm triage refers to grouping and prioritizing a stream of low-level device health information to help operators find and fix problems. Today, this process tends to be largely manual because existing tools cannot easily evolve with the network. We present CueT, a system that uses interactive machine learning to learn from the triaging decisions of operators. It then uses that learning in novel visualizations to help them quickly and accurately triage alarms. Unlike prior interactive machine learning systems, CueT handles a highly dynamic environment where the groups of interest are not known a-priori and evolve constantly. A user study with real operators and data from a large network shows that CueT significantly improves the speed and accuracy of alarm triage compared to the network's current practice. | false | false | [
"Saleema Amershi",
"Bongshin Lee",
"Ashish Kapoor",
"Ratul Mahajan",
"Blaine Christian"
] | [] | [] | [] |
CHI | 2,011 | Does MoodyBoard make internet use more secure?: evaluating an ambient security visualization tool | 10.1145/1978942.1979072 | Internet users are targets for ever-advancing phishing- and other attacks. The risks are, for example, to disclose credit card information or passwords to unauthorized instances. One approach to help users with insecure situations is provided by MoodyBoard, which uses ambient information to highlight potential risks. In this paper, we present findings from an evaluation of this system. Two user studies were conducted in order to find out whether an ambient security tool can protect users during sensitive tasks. We designed a pilot study to find out whether users understand the warnings and a security study to see if it helps to protect users from phishing attacks. Results show that MoodyBoard users behaved significantly more secure. | false | false | [
"Alexander De Luca",
"Bernhard Frauendienst",
"Max-Emanuel Maurer",
"Julian Seifert",
"Doris Hausen",
"Niels Kammerer",
"Heinrich Hussmann"
] | [] | [] | [] |
CHI | 2,011 | Enhancing credibility judgment of web search results | 10.1145/1978942.1979126 | In this paper, we propose a system for helping users to judge the credibility of Web search results and to search for credible Web pages. Conventional Web search engines present only titles, snippets, and URLs for users, which give few clues to judge the credibility of Web search results. Moreover, ranking algorithms of the conventional Web search engines are often based on relevance and popularity of Web pages. Towards credibility-oriented Web search, our proposed system provides users with the following three functions: (1) calculation and visualization of several scores of Web search results on the main credibility aspects, (2) prediction of user's credibility judgment model through user's credibility feedback for Web search results, and (3) re-ranking of Web search results based on user's predicted credibility model. Experimental results suggest that our system enables users - in particular, users with knowledge about search topics - to find credible Web pages from a list of Web search results more efficiently than conventional Web search interfaces. | false | false | [
"Yusuke Yamamoto",
"Katsumi Tanaka"
] | [] | [] | [] |
CHI | 2,011 | Evaluating longitudinal projects combining technology with temporal arts | 10.1145/1978942.1979209 | The integration of interactive technology with temporal art such as dance is an exciting, emerging area. The design space for such collaborations is immense, with variations in sensors, visualizations, and how these interact with dancers and choreography. This paper presents the evaluation methodology and results of Dance.Draw, a longitudinal project spanning two years and three productions, which aimed to develop a deep, interdisciplinary understanding of this space. Given that this is pioneering work, there is little guidance on how to evaluate such collaborations. We describe the significant confounds in doing evaluation in this area, and we present our evolving mixed-methods approach, which includes two unique methods to address the multiple stakeholders in a holistic manner: dancer focus groups and repeated presentations. Our approach has generated insights, such as differing perspectives of audience members and the responses of dancers to technological variables. We conclude by discussing the challenges and successes of our evaluation approach. | false | false | [
"Celine Latulipe",
"Erin A. Carroll",
"Danielle M. Lottridge"
] | [] | [] | [] |
CHI | 2,011 | Evaluating video visualizations of human behavior | 10.1145/1978942.1979155 | Previously, we presented Viz-A-Vis, a VIsualiZation of Activity through computer VISion [17]. Viz-A-Vis visualizes behavior as aggregate motion over observation space. In this paper, we present two complementary user studies of Viz-A-Vis measuring its performance and discovery affordances. First, we present a controlled user study aimed at comparatively measuring behavioral analysis preference and performance for observation and search tasks. Second, we describe a study with architects measuring discovery affordances and potential impacts on their work practices. We conclude: 1) Viz-A-Vis significantly reduced search time; and 2) it increased the number and quality of insightful discoveries. | false | false | [
"Mario Romero",
"Alice Vialard",
"John Peponis",
"John T. Stasko",
"Gregory D. Abowd"
] | [] | [] | [] |
CHI | 2,011 | KronoMiner: using multi-foci navigation for the visual exploration of time-series data | 10.1145/1978942.1979195 | The need for pattern discovery in long time-series data led researchers to develop interactive visualization tools and analytical algorithms for gaining insight into the data. Most of the literature on time-series data visualization either focus on a small number of tasks or a specific domain. We propose KronoMiner, a tool that embeds new interaction and visualization techniques as well as analytical capabilities for the visual exploration of time-series data. The interface's design has been iteratively refined based on feedback from expert users. Qualitative evaluation with an expert user not involved in the design process indicates that our prototype is promising for further research. | false | false | [
"Jian Zhao 0010",
"Fanny Chevalier",
"Ravin Balakrishnan"
] | [] | [] | [] |
CHI | 2,011 | LifeFlow: visualizing an overview of event sequences | 10.1145/1978942.1979196 | Event sequence analysis is an important task in many domains: medical researchers may study the patterns of transfers within the hospital for quality control; transportation experts may study accident response logs to identify best practices. In many cases they deal with thousands of records. While previous research has focused on searching and browsing, overview tasks are often overlooked. We introduce a novel interactive visual overview of event sequences called \emph{LifeFlow}. LifeFlow is scalable, can summarize all possible sequences, and represents the temporal spacing of the events within sequences. Two case studies with healthcare and transportation domain experts are presented to illustrate the usefulness of LifeFlow. A user study with ten participants confirmed that after 15 minutes of training novice users were able to rapidly answer questions about the prevalence and temporal characteristics of sequences, find anomalies, and gain significant insight from the data. | false | false | [
"Krist Wongsuphasawat",
"John Alexis Guerra Gómez",
"Catherine Plaisant",
"Taowei David Wang",
"Meirav Taieb-Maimon",
"Ben Shneiderman"
] | [] | [] | [] |
CHI | 2,011 | Location visualization in social media applications | 10.1145/1978942.1979298 | Location sharing applications are becoming increasingly popular in social media and for use on mobile devices, yet little research has focused on their user interface design. In this paper we describe our method of charting and creating comparable designs, and present a survey-based study of 106 social media users on their preferences regarding location indicators. Our paper contributes in proposing a methodology for visual element evaluation purposes, and reveals results, e.g., that users preferred simple indicators such as points or pins for their own location, and friend location indicators to include the corresponding name. | false | false | [
"Minna Pakanen",
"Jussi Huhtala",
"Jonna Häkkilä"
] | [] | [] | [] |
CHI | 2,011 | Many bills: engaging citizens through visualizations of congressional legislation | 10.1145/1978942.1979004 | US federal legislation is a common subject of discussion and advocacy on the web, inspired by the open government movement. While the contents of these bills are freely available for download, understanding them is a significant challenge to experts and average citizens alike due to their length, complex language, and obscure topics. To make these important documents more accessible to the general public, we present Many Bills (http://manybills.us): a web-based set of visualization tools that reveals the underlying semantics of a bill. Using machine learning techniques, we classify each bill's sections based on existing document-level categories. We then visualize the resulting topic substructure of these bills. These visualizations provide an overview-and-detail view of bills, enabling users to read individual sections of a bill and compare topic patterns across multiple bills. Through an overview of the site's user activity and interviews with active users, this paper highlights how Many Bills makes the tasks of reading bills, identifying outlier sections in bills, and understanding congressperson's legislative activity more manageable. | false | false | [
"Yannick Assogba",
"Irene Ros",
"Joan Morris DiMicco",
"Matt McKeon"
] | [] | [] | [] |
CHI | 2,011 | Materializing the query with facet-streams: a hybrid surface for collaborative search on tabletops | 10.1145/1978942.1979390 | We introduce "Facet-Streams", a hybrid interactive surface for co-located collaborative product search on a tabletop. Facet-Streams combines techniques of information visualization with tangible and multi-touch interaction to materialize collaborative search on a tabletop. It harnesses the expressive power of facets and Boolean logic without exposing users to complex formal notations. Two user studies reveal how Facet-Streams unifies visual and tangible expressivity with simplicity in interaction, supports different strategies and collaboration styles, and turns product search into a fun and social experience. | false | false | [
"Hans-Christian Jetter",
"Jens Gerken",
"Michael Zöllner",
"Harald Reiterer",
"Natasa Milic-Frayling"
] | [] | [] | [] |
CHI | 2,011 | Multi-touch document folding: gesture models, fold directions and symmetries | 10.1145/1978942.1979174 | For document visualization, folding techniques provide a focus-plus-context approach with fairly high legibility on flat sections. To enable richer interaction, we explore the design space of multi-touch document folding. We discuss several design considerations for simple modeless gesturing and compatibility with standard Drag and Pinch gestures. We categorize gesture models along the characteristics of Symmetric/Asymmetric and Serial/Parallel, which yields three gesture models. We built a prototype document workspace application that integrates folding and standard gestures, and a system for testing the gesture models. A user study was conducted to compare the three models and to analyze the factors of fold direction, target symmetry, and target tolerance in user performance when folding a document to a specific shape. Our results indicate that all three factors were significant for task times, and parallelism was greater for symmetric targets. | false | false | [
"Patrick Chiu",
"Chunyuan Liao",
"Francine Chen 0001"
] | [] | [] | [] |
CHI | 2,011 | Playable data: characterizing the design space of game-y infographics | 10.1145/1978942.1979193 | This work explores the intersection between infographics and games by examining how to embed meaningful visual analytic interactions into game mechanics that in turn impact user behavior around a data-driven graphic. In contrast to other methods of narrative visualization, games provide an alternate method for structuring a story, not bound by a linear arrangement but still providing structure via rules, goals, and mechanics of play. We designed two different versions of a game-y infographic, Salubrious Nation, and compared them to a non-game-y version in an online experiment. We assessed the relative merits of the game-y approach of presentation in terms of exploration of the visualization, insights and learning, and enjoyment of the experience. Based on our results, we discuss some of the benefits and drawbacks of our designs. More generally, we identify challenges and opportunities for further exploration of this new design space. | false | false | [
"Nicholas Diakopoulos",
"Funda Kivran-Swaine",
"Mor Naaman"
] | [] | [] | [] |
CHI | 2,011 | ReadN'Karaoke: visualizing prosody in children's books for expressive oral reading | 10.1145/1978942.1979417 | We present a method for displaying prosody, the melody of speech, to aid beginning readers with fluent oral reading. We build on proven auditory techniques by manipulating and augmenting text in children's stories. The acoustic properties of a fluent recording are used to construct visualizations of pitch, loudness and length variations in read samples aligned with text. Our initial approach was to directly manipulate text, which was tested on ten children who showed significant increases in pitch modulation with manipulated text but reported difficulty with word recognition. This motivated designing the augmented text renderings, which display prosodic cues layered with text. Manipulated and augmented texts were compared with two beginning readers. Children showed similar prosodic gains with both versions and reported greater satisfaction with augmented pitch cues. Visual prosodic cues show promise for improving reading fluency in early readers and may have applications for disability education and second language learning. | false | false | [
"Rupal Patel",
"William Furr"
] | [] | [] | [] |
CHI | 2,011 | Sizing up visualizations: effects of display size in focus+context, overview+detail, and zooming interfaces | 10.1145/1978942.1979156 | Whereas the literature is clear on the benefits of large displays and visualizations, little is known about their combination, that is, how display size affect the usability of visualizations. We describe a controlled experiment where 19 participants used focus+context, overview+detail, and zooming techniques with varying display sizes (13.8, 1.5, and 0.17 megapixels). Participants navigated geographical maps to find specific locations, compare items, and follow routes. Results show that for multi-scale navigation, classic interactive visualization techniques did not benefit from being scaled to a large display: In contrast to the literature we find similar performance on medium and large displays. Across display sizes, overview+detail works the best, in particular for comparing items. Focus+context is relatively more difficult to use at a small display size. We explain these findings and discuss the design of interactive visualization techniques for large displays. | false | false | [
"Mikkel Rønne Jakobsen",
"Kasper Hornbæk"
] | [] | [] | [] |
CHI | 2,011 | The impact of social information on visual judgments | 10.1145/1978942.1979157 | Social visualization systems have emerged to support collective intelligence-driven analysis of a growing influx of open data. As with many other online systems, social signals (e.g., forums, polls) are commonly integrated to drive use. Unfortunately, the same social features that can provide rapid, high-accuracy analysis are coupled with the pitfalls of any social system. Through an experiment involving over 300 subjects, we address how social information signals (social proof) affect quantitative judgments in the context of graphical perception. We identify how unbiased social signals lead to fewer errors over non-social settings and conversely, how biased signals lead to more errors. We further reflect on how systematic bias nullifies certain collective intelligence benefits, and we provide evidence of the formation of information cascades. We describe how these findings can be applied to collaborative visualization systems to produce more accurate individual interpretations in social contexts. | false | false | [
"Jessica Hullman",
"Eytan Adar",
"Priti Shah"
] | [] | [] | [] |
CHI | 2,011 | The polymath project: lessons from a successful online collaboration in mathematics | 10.1145/1978942.1979213 | Although science is becoming increasingly collaborative, there are remarkably few success stories of online collaborations between professional scientists that actually result in real discoveries. A notable exception is the Polymath Project, a group of mathematicians who collaborate online to solve open mathematics problems. We provide an in-depth descriptive history of Polymath, using data analysis and visualization to elucidate the principles that led to its success, and the difficulties that must be addressed before the project can be scaled up. We find that although a small percentage of users created most of the content, almost all users nevertheless contributed some content that was highly influential to the task at hand. We also find that leadership played an important role in the success of the project. Based on our analysis, we present a set of design suggestions for how future collaborative mathematics sites can encourage and foster newcomer participation. | false | false | [
"Justin Cranshaw",
"Aniket Kittur"
] | [] | [] | [] |
CHI | 2,011 | Twitinfo: aggregating and visualizing microblogs for event exploration | 10.1145/1978942.1978975 | Microblogs are a tremendous repository of user-generated content about world events. However, for people trying to understand events by querying services like Twitter, a chronological log of posts makes it very difficult to get a detailed understanding of an event. In this paper, we present TwitInfo, a system for visualizing and summarizing events on Twitter. TwitInfo allows users to browse a large collection of tweets using a timeline-based display that highlights peaks of high tweet activity. A novel streaming algorithm automatically discovers these peaks and labels them meaningfully using text from the tweets. Users can drill down to subevents, and explore further via geolocation, sentiment, and popular URLs. We contribute a recall-normalized aggregate sentiment visualization to produce more honest sentiment overviews. An evaluation of the system revealed that users were able to reconstruct meaningful summaries of events in a small amount of time. An interview with a Pulitzer Prize-winning journalist suggested that the system would be especially useful for understanding a long-running event and for identifying eyewitnesses. Quantitatively, our system can identify 80-100% of manually labeled peaks, facilitating a relatively complete view of each event studied. | false | false | [
"Adam Marcus 0002",
"Michael S. Bernstein",
"Osama Badar",
"David R. Karger",
"Samuel Madden 0001",
"Robert C. Miller"
] | [] | [] | [] |
Vis | 2,010 | A Curved Ray Camera for Handling Occlusions through Continuous Multiperspective Visualization | 10.1109/TVCG.2010.127 | Most images used in visualization are computed with the planar pinhole camera. This classic camera model has important advantages such as simplicity, which enables efficient software and hardware implementations, and similarity to the human eye, which yields images familiar to the user. However, the planar pinhole camera has only a single viewpoint, which limits images to parts of the scene to which there is direct line of sight. In this paper we introduce the curved ray camera to address the single viewpoint limitation. Rays are C<sup>1</sup>-continuous curves that bend to circumvent occluders. Our camera is designed to provide a fast 3-D point projection operation, which enables interactive visualization. The camera supports both 3-D surface and volume datasets. The camera is a powerful tool that enables seamless integration of multiple perspectives for overcoming occlusions in visualization while minimizing distortions. | false | false | [
"Jian Cui",
"Paul Rosen 0001",
"Voicu Popescu",
"Christoph M. Hoffmann"
] | [] | [] | [] |
Vis | 2,010 | A Scalable Distributed Paradigm for Multi-User Interaction with Tiled Rear Projection Display Walls | 10.1109/TVCG.2010.128 | We present the first distributed paradigm for multiple users to interact simultaneously with large tiled rear projection display walls. Unlike earlier works, our paradigm allows easy scalability across different applications, interaction modalities, displays and users. The novelty of the design lies in its distributed nature allowing well-compartmented, application independent, and application specific modules. This enables adapting to different 2D applications and interaction modalities easily by changing a few application specific modules. We demonstrate four challenging 2D applications on a nine projector display to demonstrate the application scalability of our method: map visualization, virtual graffiti, virtual bulletin board and an emergency management system. We demonstrate the scalability of our method to multiple interaction modalities by showing both gesture-based and laser-based user interfaces. Finally, we improve earlier distributed methods to register multiple projectors. Previous works need multiple patterns to identify the neighbors, the configuration of the display and the registration across multiple projectors in logarithmic time with respect to the number of projectors in the display. We propose a new approach that achieves this using a single pattern based on specially augmented QR codes in constant time. Further, previous distributed registration algorithms are prone to large misregistrations. We propose a novel radially cascading geometric registration technique that yields significantly better accuracy. Thus, our improvements allow a significantly more efficient and accurate technique for distributed self-registration of multi-projector display walls. | false | false | [
"Pablo Roman",
"Maxim Lazarov",
"Aditi Majumder"
] | [] | [] | [] |
Vis | 2,010 | An Information-Theoretic Framework for Flow Visualization | 10.1109/TVCG.2010.131 | The process of visualization can be seen as a visual communication channel where the input to the channel is the raw data, and the output is the result of a visualization algorithm. From this point of view, we can evaluate the effectiveness of visualization by measuring how much information in the original data is being communicated through the visual communication channel. In this paper, we present an information-theoretic framework for flow visualization with a special focus on streamline generation. In our framework, a vector field is modeled as a distribution of directions from which Shannon's entropy is used to measure the information content in the field. The effectiveness of the streamlines displayed in visualization can be measured by first constructing a new distribution of vectors derived from the existing streamlines, and then comparing this distribution with that of the original data set using the conditional entropy. The conditional entropy between these two distributions indicates how much information in the original data remains hidden after the selected streamlines are displayed. The quality of the visualization can be improved by progressively introducing new streamlines until the conditional entropy converges to a small value. We describe the key components of our framework with detailed analysis, and show that the framework can effectively visualize 2D and 3D flow data. | false | false | [
"Lijie Xu",
"Teng-Yok Lee",
"Han-Wei Shen"
] | [] | [] | [] |
Vis | 2,010 | An Information-theoretic Framework for Visualization | 10.1109/TVCG.2010.132 | In this paper, we examine whether or not information theory can be one of the theoretic frameworks for visualization. We formulate concepts and measurements for qualifying visual information. We illustrate these concepts with examples that manifest the intrinsic and implicit use of information theory in many existing visualization techniques. We outline the broad correlation between visualization and the major applications of information theory, while pointing out the difference in emphasis and some technical gaps. Our study provides compelling evidence that information theory can explain a significant number of phenomena or events in visualization, while no example has been found which is fundamentally in conflict with information theory. We also notice that the emphasis of some traditional applications of information theory, such as data compression or data communication, may not always suit visualization, as the former typically focuses on the efficient throughput of a communication channel, whilst the latter focuses on the effectiveness in aiding the perceptual and cognitive process for data understanding and knowledge discovery. These findings suggest that further theoretic developments are necessary for adopting and adapting information theory for visualization. | false | false | [
"Min Chen 0001",
"Heike Leitte"
] | [
"TT"
] | [] | [] |
Vis | 2,010 | Analysis of Recurrent Patterns in Toroidal Magnetic fields | 10.1109/TVCG.2010.133 | In the development of magnetic confinement fusion which will potentially be a future source for low cost power, physicists must be able to analyze the magnetic field that confines the burning plasma. While the magnetic field can be described as a vector field, traditional techniques for analyzing the field's topology cannot be used because of its Hamiltonian nature. In this paper we describe a technique developed as a collaboration between physicists and computer scientists that determines the topology of a toroidal magnetic field using fieldlines with near minimal lengths. More specifically, we analyze the Poincaré map of the sampled fieldlines in a Poincaré section including identifying critical points and other topological features of interest to physicists. The technique has been deployed into an interactiveparallel visualization tool which physicists are using to gain new insight into simulations of magnetically confined burning plasmas. | false | false | [
"Allen R. Sanderson",
"Guoning Chen",
"Xavier Tricoche",
"David Pugmire",
"Scott Kruger",
"Joshua A. Breslau"
] | [] | [] | [] |
Vis | 2,010 | Articulated Planar Reformation for Change Visualization in Small Animal Imaging | 10.1109/TVCG.2010.134 | The analysis of multi-timepoint whole-body small animal CT data is greatly complicated by the varying posture of the subject at different timepoints. Due to these variations, correctly relating and comparing corresponding regions of interest is challenging.In addition, occlusion may prevent effective visualization of these regions of interest. To address these problems, we have developed a method that fully automatically maps the data to a standardized layout of sub-volumes, based on an articulated atlas registration.We have dubbed this process articulated planar reformation, or APR. A sub-volume can be interactively selected for closer inspection and can be compared with the corresponding sub-volume at the other timepoints, employing a number of different comparative visualization approaches. We provide an additional tool that highlights possibly interesting areas based on the change of bone density between timepoints. Furthermore we allow visualization of the local registration error, to give an indication of the accuracy of the registration. We have evaluated our approach on a case that exhibits cancer-induced bone resorption. | false | false | [
"Peter Kok",
"Martin Baiker",
"Emile A. Hendriks",
"Frits H. Post",
"Jouke Dijkstra",
"Clemens W. G. M. Löwik",
"Boudewijn P. F. Lelieveldt",
"Charl P. Botha"
] | [] | [] | [] |
Vis | 2,010 | Browsing Large Image Datasets through Voronoi Diagrams | 10.1109/TVCG.2010.136 | Conventional browsing of image collections use mechanisms such as thumbnails arranged on a regular grid or on a line, often mounted over a scrollable panel. However, this approach does not scale well with the size of the datasets (number of images). In this paper, we propose a new thumbnail-based interface to browse large collections of images. Our approach is based on weighted centroidal anisotropic Voronoi diagrams. A dynamically changing subset of images is represented by thumbnails and shown on the screen. Thumbnails are shaped like general polygons, to better cover screen space, while still reflecting the original aspect ratios or orientation of the represented images. During the browsing process, thumbnails are dynamically rearranged, reshaped and rescaled. The objective is to devote more screen space (more numerous and larger thumbnails) to the parts of the dataset closer to the current region of interest, and progressively lesser away from it, while still making the dataset visible as a whole. During the entire process, temporal coherence is always maintained. GPU implementation easily guarantees the frame rates needed for fully smooth interactivity. | false | false | [
"Paolo Brivio",
"Marco Tarini",
"Paolo Cignoni"
] | [] | [] | [] |
Vis | 2,010 | Computing Robustness and Persistence for Images | 10.1109/TVCG.2010.139 | We are interested in 3-dimensional images given as arrays of voxels with intensity values. Extending these values to a continuous function, we study the robustness of homology classes in its level and interlevel sets, that is, the amount of perturbation needed to destroy these classes. The structure of the homology classes and their robustness, over all level and interlevel sets, can be visualized by a triangular diagram of dots obtained by computing the extended persistence of the function. We give a fast hierarchical algorithm using the dual complexes of oct-tree approximations of the function. In addition, we show that for balanced oct-trees, the dual complexes are geometrically realized in R<sup>3</sup> and can thus be used to construct level and interlevel sets. We apply these tools to study 3-dimensional images of plant root systems. | false | false | [
"Paul Bendich",
"Herbert Edelsbrunner",
"Michael Kerber"
] | [] | [] | [] |
Vis | 2,010 | Direct Interval Volume Visualization | 10.1109/TVCG.2010.145 | We extend direct volume rendering with a unified model for generalized isosurfaces, also called interval volumes, allowing a wider spectrum of visual classification. We generalize the concept of scale-invariant opacity-typical for isosurface rendering-to semi-transparent interval volumes. Scale-invariant rendering is independent of physical space dimensions and therefore directly facilitates the analysis of data characteristics. Our model represents sharp isosurfaces as limits of interval volumes and combines them with features of direct volume rendering. Our objective is accurate rendering, guaranteeing that all isosurfaces and interval volumes are visualized in a crack-free way with correct spatial ordering. We achieve simultaneous direct and interval volume rendering by extending preintegration and explicit peak finding with data-driven splitting of ray integration and hybrid computation in physical and data domains. Our algorithm is suitable for efficient parallel processing for interactive applications as demonstrated by our CUDA implementation. | false | false | [
"Marco Ament",
"Daniel Weiskopf",
"Hamish A. Carr"
] | [] | [] | [] |
Vis | 2,010 | Discontinuities in Continuous Scatterplots | 10.1109/TVCG.2010.146 | The concept of continuous scatterplot (CSP) is a modern visualization technique. The idea is to define a scalar density value based on the map between an n-dimensional spatial domain and an m-dimensional data domain, which describe the CSP space. Usually the data domain is two-dimensional to visually convey the underlying, density coded, data. In this paper we investigate kinds of map-based discontinuities, especially for the practical cases n = m = 2 and n = 3 | m = 2, and we depict relations between them and attributes of the resulting CSP itself. Additionally, we show that discontinuities build critical line structures, and we introduce algorithms to detect them. Further, we introduce a discontinuity-based visualization approach - called contribution map (CM) -which establishes a relationship between the CSP's data domain and the number of connected components in the spatial domain. We show that CMs enhance the CSP-based linking &amp; brushing interaction. Finally, we apply our approaches to a number of synthetic as well as real data sets. | false | false | [
"Dirk J. Lehmann",
"Holger Theisel"
] | [] | [] | [] |
Vis | 2,010 | Edge Aware Anisotropic Diffusion for 3D Scalar Data | 10.1109/TVCG.2010.147 | In this paper we present a novel anisotropic diffusion model targeted for 3D scalar field data. Our model preserves material boundaries as well as fine tubular structures while noise is smoothed out. One of the major novelties is the use of the directional second derivative to define material boundaries instead of the gradient magnitude for thresholding. This results in a diffusion model that has much lower sensitivity to the diffusion parameter and smoothes material boundaries consistently compared to gradient magnitude based techniques. We empirically analyze the stability and convergence of the proposed diffusion and demonstrate its de-noising capabilities for both analytic and real data. We also discuss applications in the context of volume rendering. | false | false | [
"Zahid Hossain 0001",
"Torsten Möller"
] | [] | [] | [] |
Vis | 2,010 | Efficient High-Quality Volume Rendering of SPH Data | 10.1109/TVCG.2010.148 | High quality volume rendering of SPH data requires a complex order-dependent resampling of particle quantities along the view rays. In this paper we present an efficient approach to perform this task using a novel view-space discretization of the simulation domain. Our method draws upon recent work on GPU-based particle voxelization for the efficient resampling of particles into uniform grids. We propose a new technique that leverages a perspective grid to adaptively discretize the view-volume, giving rise to a continuous level-of-detail sampling structure and reducing memory requirements compared to a uniform grid. In combination with a level-of-detail representation of the particle set, the perspective grid allows effectively reducing the amount of primitives to be processed at run-time. We demonstrate the quality and performance of our method for the rendering of fluid and gas dynamics SPH simulations consisting of many millions of particles. | false | false | [
"Roland Fraedrich",
"Stefan Auer",
"Rüdiger Westermann"
] | [] | [] | [] |
Vis | 2,010 | Exploded View Diagrams of Mathematical Surfaces | 10.1109/TVCG.2010.151 | We present a technique for visualizing complicated mathematical surfaces that is inspired by hand-designed topological illustrations. Our approach generates exploded views that expose the internal structure of such a surface by partitioning it into parallel slices, which are separated from each other along a single linear explosion axis. Our contributions include a set of simple, prescriptive design rules for choosing an explosion axis and placing cutting planes, as well as automatic algorithms for applying these rules. First we analyze the input shape to select the explosion axis based on the detected rotational and reflective symmetries of the input model. We then partition the shape into slices that are designed to help viewers better understand how the shape of the surface and its cross-sections vary along the explosion axis. Our algorithms work directly on triangle meshes, and do not depend on any specific parameterization of the surface. We generate exploded views for a variety of mathematical surfaces using our system. | false | false | [
"Olga A. Karpenko",
"Wilmot Li",
"Niloy J. Mitra",
"Maneesh Agrawala"
] | [] | [] | [] |
Vis | 2,010 | Exploration and Visualization of Segmentation Uncertainty using Shape and Appearance Prior Information | 10.1109/TVCG.2010.152 | We develop an interactive analysis and visualization tool for probabilistic segmentation in medical imaging. The originality of our approach is that the data exploration is guided by shape and appearance knowledge learned from expert-segmented images of a training population. We introduce a set of multidimensional transfer function widgets to analyze the multivariate probabilistic field data. These widgets furnish the user with contextual information about conformance or deviation from the population statistics. We demonstrate the user's ability to identify suspicious regions (e.g. tumors) and to correct the misclassification results. We evaluate our system and demonstrate its usefulness in the context of static anatomical and time-varying functional imaging datasets. | false | false | [
"Ahmed Saad",
"Ghassan Hamarneh",
"Torsten Möller"
] | [] | [] | [] |
Vis | 2,010 | Exploration of 4D MRI Blood Flow using Stylistic Visualization | 10.1109/TVCG.2010.153 | Insight into the dynamics of blood-flow considerably improves the understanding of the complex cardiovascular system and its pathologies. Advances in MRI technology enable acquisition of 4D blood-flow data, providing quantitative blood-flow velocities over time. The currently typical slice-by-slice analysis requires a full mental reconstruction of the unsteady blood-flow field, which is a tedious and highly challenging task, even for skilled physicians. We endeavor to alleviate this task by means of comprehensive visualization and interaction techniques. In this paper we present a framework for pre-clinical cardiovascular research, providing tools to both interactively explore the 4D blood-flow data and depict the essential blood-flow characteristics. The framework encompasses a variety of visualization styles, comprising illustrative techniques as well as improved methods from the established field of flow visualization. Each of the incorporated styles, including exploded planar reformats, flow-direction highlights, and arrow-trails, locally captures the blood-flow dynamics and may be initiated by an interactively probed vessel cross-section. Additionally, we present the results of an evaluation with domain experts, measuring the value of each of the visualization styles and related rendering parameters. | false | false | [
"Roy van Pelt",
"Javier Oliván Bescós",
"Marcel Breeuwer",
"Rachel E. Clough",
"M. Eduard Gröller",
"Bart M. ter Haar Romeny",
"Anna Vilanova"
] | [] | [] | [] |
Vis | 2,010 | Fast High-Quality Volume Ray Casting with Virtual Samplings | 10.1109/TVCG.2010.155 | Volume ray-casting with a higher order reconstruction filter and/or a higher sampling rate has been adopted in direct volume rendering frameworks to provide a smooth reconstruction of the volume scalar and/or to reduce artifacts when the combined frequency of the volume and transfer function is high. While it enables high-quality volume rendering, it cannot support interactive rendering due to its high computational cost. In this paper, we propose a fast high-quality volume ray-casting algorithm which effectively increases the sampling rate. While a ray traverses the volume, intensity values are uniformly reconstructed using a high-order convolution filter. Additional samplings, referred to as virtual samplings, are carried out within a ray segment from a cubic spline curve interpolating those uniformly reconstructed intensities. These virtual samplings are performed by evaluating the polynomial function of the cubic spline curve via simple arithmetic operations. The min max blocks are refined accordingly for accurate empty space skipping in the proposed method. Experimental results demonstrate that the proposed algorithm, also exploiting fast cubic texture filtering supported by programmable GPUs, offers renderings as good as a conventional ray-casting algorithm using high-order reconstruction filtering at the same sampling rate, while delivering 2.5x to 3.3x rendering speed-up. | false | false | [
"Byeonghun Lee",
"Jihye Yun",
"Jinwook Seo",
"Byonghyo Shim",
"Yeong-Gil Shin",
"Bo Hyoung Kim"
] | [] | [] | [] |
Vis | 2,010 | Fast; Memory-Efficient Cell Location in Unstructured Grids for Visualization | 10.1109/TVCG.2010.156 | Applying certain visualization techniques to datasets described on unstructured grids requires the interpolation of variables of interest at arbitrary locations within the dataset's domain of definition. Typical solutions to the problem of finding the grid element enclosing a given interpolation point make use of a variety of spatial subdivision schemes. However, existing solutions are memory- intensive, do not scale well to large grids, or do not work reliably on grids describing complex geometries. In this paper, we propose a data structure and associated construction algorithm for fast cell location in unstructured grids, and apply it to the interpolation problem. Based on the concept of bounding interval hierarchies, the proposed approach is memory-efficient, fast and numerically robust. We examine the performance characteristics of the proposed approach and compare it to existing approaches using a number of benchmark problems related to vector field visualization. Furthermore, we demonstrate that our approach can successfully accommodate large datasets, and discuss application to visualization on both CPUs and GPUs. | false | false | [
"Christoph Garth",
"Kenneth I. Joy"
] | [] | [] | [] |
Vis | 2,010 | FI3D: Direct-Touch Interaction for the Exploration of 3D Scientific Visualization Spaces | 10.1109/TVCG.2010.157 | We present the design and evaluation of FI3D, a direct-touch data exploration technique for 3D visualization spaces. The exploration of three-dimensional data is core to many tasks and domains involving scientific visualizations. Thus, effective data navigation techniques are essential to enable comprehension, understanding, and analysis of the information space. While evidence exists that touch can provide higher-bandwidth input, somesthetic information that is valuable when interacting with virtual worlds, and awareness when working in collaboration, scientific data exploration in 3D poses unique challenges to the development of effective data manipulations. We present a technique that provides touch interaction with 3D scientific data spaces in 7 DOF. This interaction does not require the presence of dedicated objects to constrain the mapping, a design decision important for many scientific datasets such as particle simulations in astronomy or physics. We report on an evaluation that compares the technique to conventional mouse-based interaction. Our results show that touch interaction is competitive in interaction speed for translation and integrated interaction, is easy to learn and use, and is preferred for exploration and wayfinding tasks. To further explore the applicability of our basic technique for other types of scientific visualizations we present a second case study, adjusting the interaction to the illustrative visualization of fiber tracts of the brain and the manipulation of cutting planes in this context. | false | false | [
"Lingyun Yu 0001",
"Pjotr Svetachov",
"Petra Isenberg",
"Maarten H. Everts",
"Tobias Isenberg 0001"
] | [] | [] | [] |
Vis | 2,010 | Gradient Estimation Revitalized | 10.1109/TVCG.2010.160 | We investigate the use of a Fourier-domain derivative error kernel to quantify the error incurred while estimating the gradient of a function from scalar point samples on a regular lattice. We use the error kernel to show that gradient reconstruction quality is significantly enhanced merely by shifting the reconstruction kernel to the centers of the principal lattice directions. Additionally, we exploit the algebraic similarities between the scalar and derivative error kernels to design asymptotically optimal gradient estimation filters that can be factored into an infinite impulse response interpolation prefilter and a finite impulse response directional derivative filter. This leads to a significant performance gain both in terms of accuracy and computational efficiency. The interpolation prefilter provides an accurate scalar approximation and can be re-used to cheaply compute directional derivatives on-the-fly without the need to store gradients. We demonstrate the impact of our filters in the context of volume rendering of scalar data sampled on the Cartesian and Body-Centered Cubic lattices. Our results rival those obtained from other competitive gradient estimation methods while incurring no additional computational or storage overhead. | false | false | [
"Usman R. Alim",
"Torsten Möller",
"Laurent Condat"
] | [] | [] | [] |
Vis | 2,010 | Illustrative Stream Surfaces | 10.1109/TVCG.2010.166 | Stream surfaces are an intuitive approach to represent 3D vector fields. In many cases, however, they are challenging objects to visualize and to understand, due to a high degree of self-occlusion. Despite the need for adequate rendering methods, little work has been done so far in this important research area. In this paper, we present an illustrative rendering strategy for stream surfaces. In our approach, we apply various rendering techniques, which are inspired by the traditional flow illustrations drawn by Dallmann and Abraham & Shaw in the early 1980s. Among these techniques are contour lines and halftoning to show the overall surface shape. Flow direction as well as singularities on the stream surface are depicted by illustrative surface streamlines. ;To go beyond reproducing static text book images, we provide several interaction features, such as movable cuts and slabs allowing an interactive exploration of the flow and insights into subjacent structures, e.g., the inner windings of vortex breakdown bubbles. These methods take only the parameterized stream surface as input, require no further preprocessing, and can be freely combined by the user. We explain the design, GPU-implementation, and combination of the different illustrative rendering and interaction methods and demonstrate the potential of our approach by applying it to stream surfaces from various flow simulations. | false | false | [
"Silvia Born",
"Alexander Wiebel",
"Jan Friedrich",
"Gerik Scheuermann",
"Dirk Bartz"
] | [
"HM"
] | [] | [] |
Vis | 2,010 | Interactive Histology of Large-Scale Biomedical Image Stacks | 10.1109/TVCG.2010.168 | Histology is the study of the structure of biological tissue using microscopy techniques. As digital imaging technology advances, high resolution microscopy of large tissue volumes is becoming feasible; however, new interactive tools are needed to explore and analyze the enormous datasets. In this paper we present a visualization framework that specifically targets interactive examination of arbitrarily large image stacks. Our framework is built upon two core techniques: display-aware processing and GPU-accelerated texture compression. With display-aware processing, only the currently visible image tiles are fetched and aligned on-the-fly, reducing memory bandwidth and minimizing the need for time-consuming global pre-processing. Our novel texture compression scheme for GPUs is tailored for quick browsing of image stacks. We evaluate the usability of our viewer for two histology applications: digital pathology and visualization of neural structure at nanoscale-resolution in serial electron micrographs. | false | false | [
"Won-Ki Jeong",
"Jens Schneider 0002",
"Stephen G. Turney",
"Beverly E. Faulkner-Jones",
"Dominik Meyer",
"Rüdiger Westermann",
"R. Clay Reid",
"Jeff Lichtman",
"Hanspeter Pfister"
] | [] | [] | [] |
Vis | 2,010 | Interactive Separating Streak Surfaces | 10.1109/TVCG.2010.169 | Streak surfaces are among the most important features to support 3D unsteady flow exploration, but they are also among the computationally most demanding. Furthermore, to enable a feature driven analysis of the flow, one is mainly interested in streak surfaces that show separation profiles and thus detect unstable manifolds in the flow. The computation of such separation surfaces requires to place seeding structures at the separation locations and to let the structures move correspondingly to these locations in the unsteady flow. Since only little knowledge exists about the time evolution of separating streak surfaces, at this time, an automated exploration of 3D unsteady flows using such surfaces is not feasible. Therefore, in this paper we present an interactive approach for the visual analysis of separating streak surfaces. Our method draws upon recent work on the extraction of Lagrangian coherent structures (LCS) and the real-time visualization of streak surfaces on the GPU. We propose an interactive technique for computing ridges in the finite time Lyapunov exponent (FTLE) field at each time step, and we use these ridges as seeding structures to track streak surfaces in the time-varying flow. By showing separation surfaces in combination with particle trajectories, and by letting the user interactively change seeding parameters such as particle density and position, visually guided exploration of separation profiles in 3D is provided. To the best of our knowledge, this is the first time that the reconstruction and display of semantic separable surfaces in 3D unsteady flows can be performed interactively, giving rise to new possibilities for gaining insight into complex flow phenomena. | false | false | [
"Florian Ferstl",
"Kai Bürger",
"Holger Theisel",
"Rüdiger Westermann"
] | [] | [] | [] |
Vis | 2,010 | Interactive Vector field Feature Identification | 10.1109/TVCG.2010.170 | We introduce a flexible technique for interactive exploration of vector field data through classification derived from user-specified feature templates. Our method is founded on the observation that, while similar features within the vector field may be spatially disparate, they share similar neighborhood characteristics. Users generate feature-based visualizations by interactively highlighting well-accepted and domain specific representative feature points. Feature exploration begins with the computation of attributes that describe the neighborhood of each sample within the input vector field. Compilation of these attributes forms a representation of the vector field samples in the attribute space. We project the attribute points onto the canonical 2D plane to enable interactive exploration of the vector field using a painting interface. The projection encodes the similarities between vector field points within the distances computed between their associated attribute points. The proposed method is performed at interactive rates for enhanced user experience and is completely flexible as showcased by the simultaneous identification of diverse feature types. | false | false | [
"Joel Daniels II",
"Erik W. Anderson",
"Luis Gustavo Nonato",
"Cláudio T. Silva"
] | [] | [] | [] |
Vis | 2,010 | Interactive Visual Analysis of Multiple Simulation Runs Using the Simulation Model View: Understanding and Tuning of an Electronic Unit Injector | 10.1109/TVCG.2010.171 | Multiple simulation runs using the same simulation model with different values of control parameters generate a large data set that captures the behavior of the modeled phenomenon. However, there is a conceptual and visual gap between the simulation model behavior and the data set that makes data analysis more difficult. We propose a simulation model view that helps to bridge that gap by visually combining the simulation model description and the generated data. The simulation model view provides a visual outline of the simulation process and the corresponding simulation model. The view is integrated in a Coordinated Multiple Views; (CMV) system. As the simulation model view provides a limited display space, we use three levels of details. We explored the use of the simulation model view, in close collaboration with a domain expert, to understand and tune an electronic unit injector (EUI). We also developed analysis procedures based on the view. The EUI is mostly used in heavy duty Diesel engines. We were mainly interested in understanding the model and how to tune it for three different operation modes: low emission, low consumption, and high power. Very positive feedback from the domain expert shows that the use of the simulation model view and the corresponding ;analysis procedures within a CMV system represents an effective technique for interactive visual analysis of multiple simulation runs. | false | false | [
"Kresimir Matkovic",
"Denis Gracanin",
"Mario Jelovic",
"Andreas Ammer",
"Alan Lez",
"Helwig Hauser"
] | [] | [] | [] |
Vis | 2,010 | Interactive Visualization of Hyperspectral Images of Historical Documents | 10.1109/TVCG.2010.172 | This paper presents an interactive visualization tool to study and analyze hyperspectral images (HSI) of historical documents. This work is part of a collaborative effort with the Nationaal Archief of the Netherlands (NAN) and Art Innovation, a manufacturer of hyperspectral imaging hardware designed for old and fragile documents. The NAN is actively capturing HSI of historical documents for use in a variety of tasks related to the analysis and management of archival collections, from ink and paper analysis to monitoring the effects of environmental aging. To assist their work, we have developed a comprehensive visualization tool that offers an assortment of visualization and analysis methods, including interactive spectral selection, spectral similarity analysis, time-varying data analysis and visualization, and selective spectral band fusion. This paper describes our visualization software and how it is used to facilitate the tasks needed by our collaborators. Evaluation feedback from our collaborators on how this tool benefits their work is included. | false | false | [
"Seon Joo Kim",
"Shaojie Zhuo",
"Fanbo Deng",
"Chi-Wing Fu",
"Michael S. Brown"
] | [] | [] | [] |
Vis | 2,010 | IRIS: Illustrative Rendering for Integral Surfaces | 10.1109/TVCG.2010.173 | Integral surfaces are ideal tools to illustrate vector fields and fluid flow structures. However, these surfaces can be visually complex and exhibit difficult geometric properties, owing to strong stretching, shearing and folding of the flow from which they are derived. Many techniques for non-photorealistic rendering have been presented previously. It is, however, unclear how these techniques can be applied to integral surfaces. In this paper, we examine how transparency and texturing techniques can be used with integral surfaces to convey both shape and directional information. We present a rendering pipeline that combines these techniques aimed at faithfully and accurately representing integral surfaces while improving visualization insight. The presented pipeline is implemented directly on the GPU, providing real-time interaction for all rendering modes, and does not require expensive preprocessing of integral surfaces after computation. | false | false | [
"Mathias Hummel",
"Christoph Garth",
"Bernd Hamann",
"Hans Hagen",
"Kenneth I. Joy"
] | [] | [] | [] |
Vis | 2,010 | Noodles: A Tool for Visualization of Numerical Weather Model Ensemble Uncertainty | 10.1109/TVCG.2010.181 | Numerical weather prediction ensembles are routinely used for operational weather forecasting. The members of these ensembles are individual simulations with either slightly perturbed initial conditions or different model parameterizations, or occasionally both. Multi-member ensemble output is usually large, multivariate, and challenging to interpret interactively. Forecast meteorologists are interested in understanding the uncertainties associated with numerical weather prediction; specifically variability between the ensemble members. Currently, visualization of ensemble members is mostly accomplished through spaghetti plots of a single midtroposphere pressure surface height contour. In order to explore new uncertainty visualization methods, the Weather Research and Forecasting (WRF) model was used to create a 48-hour, 18 member parameterization ensemble of the 13 March 1993 "Superstorm". A tool was designed to interactively explore the ensemble uncertainty of three important weather variables: water-vapor mixing ratio, perturbation potential temperature, and perturbation pressure. Uncertainty was quantified using individual ensemble member standard deviation, inter-quartile range, and the width of the 95% confidence interval. Bootstrapping was employed to overcome the dependence on normality in the uncertainty metrics. A coordinated view of ribbon and glyph-based uncertainty visualization, spaghetti plots, iso-pressure colormaps, and data transect plots was provided to two meteorologists for expert evaluation. They found it useful in assessing uncertainty in the data, especially in finding outliers in the ensemble run and therefore avoiding the WRF parameterizations that lead to these outliers. Additionally, the meteorologists could identify spatial regions where the uncertainty was significantly high, allowing for identification of poorly simulated storm environments and physical interpretation of these model issues. | false | false | [
"Jibonananda Sanyal",
"Song Zhang 0004",
"Jamie L. Dyer",
"Andrew Mercer 0001",
"Philip Amburn",
"Robert J. Moorhead II"
] | [] | [] | [] |
Vis | 2,010 | On the Fractal Dimension of Isosurfaces | 10.1109/TVCG.2010.182 | A (3D) scalar grid is a regular n1× n2× n3grid of vertices where each vertex v is associated with some scalar value sv. Applying trilinear interpolation, the scalar grid determines a scalar function g where g(v) = svfor each grid vertex v. An isosurface with isovalue σ is a triangular mesh which approximates the level set g-1(σ). The fractal dimension of an isosurface represents the growth in the isosurface as the number of grid cubes increases. We define and discuss the fractal isosurface dimension. Plotting the fractal dimension as a function of the isovalues in a data set provides information about the isosurfaces determined by the data set. We present statistics on the average fractal dimension of 60 publicly available benchmark data sets. We also show the fractal dimension is highly correlated with topological noise in the benchmark data sets, measuring the topological noise by the number of connected components in the isosurface. Lastly, we present a formula predicting the fractal dimension as a function of noise and validate the formula with experimental results. | false | false | [
"Marc Khoury",
"Rephael Wenger"
] | [] | [] | [] |
Vis | 2,010 | Pre-Integrated Volume Rendering with Non-Linear Gradient Interpolation | 10.1109/TVCG.2010.187 | Shading is an important feature for the comprehension of volume datasets, but is difficult to implement accurately. Current techniques based on pre-integrated direct volume rendering approximate the volume rendering integral by ignoring non-linear gradient variations between front and back samples, which might result in cumulated shading errors when gradient variations are important and / or when the illumination function features high frequencies. In this paper, we explore a simple approach for pre-integrated volume rendering with non-linear gradient interpolation between front and back samples. We consider that the gradient smoothly varies along a quadratic curve instead of a segment in-between consecutive samples. This not only allows us to compute more accurate shaded pre-integrated look-up tables, but also allows us to more efficiently process shading amplifying effects, based on gradient filtering. An interesting property is that the pre-integration tables we use remain two-dimensional as for usual pre-integrated classification. We conduct experiments using a full hardware approach with the Blinn-Phong illumination model as well as with a non-photorealistic illumination model. | false | false | [
"Amel Guetat",
"Alexandre Ancel",
"Stéphane Marchesin",
"Jean-Michel Dischler"
] | [] | [] | [] |
Vis | 2,010 | Projector Placement Planning for High Quality Visualizations on Real-World Colored Objects | 10.1109/TVCG.2010.189 | Many visualization applications benefit from displaying content on real-world objects rather than on a traditional display (e.g., a monitor). This type of visualization display is achieved by projecting precisely controlled illumination from multiple projectors onto the real-world colored objects. For such a task, the placement of the projectors is critical in assuring that the desired visualization is possible. Using ad hoc projector placement may cause some appearances to suffer from color shifting due to insufficient projector light radiance being exposed onto the physical surface. This leads to an incorrect appearance and ultimately to a false and potentially misleading visualization. In this paper, we present a framework to discover the optimal position and orientation of the projectors for such projection-based visualization displays. An optimal projector placement should be able to achieve the desired visualization with minimal projector light radiance. When determining optimal projector placement, object visibility, surface reflectance properties, and projector-surface distance and orientation need to be considered. We first formalize a theory for appearance editing image formation and construct a constrained linear system of equations that express when a desired novel appearance or visualization is possible given a geometric and surface reflectance model of the physical surface. Then, we show how to apply this constrained system in an adaptive search to efficiently discover the optimal projector placement which achieves the desired appearance. Constraints can be imposed on the maximum radiance allowed by the projectors and the projectors' placement to support specific goals of various visualization applications. We perform several real-world and simulated appearance edits and visualizations to demonstrate the improvement obtained by our discovered projector placement over ad hoc projector placement. | false | false | [
"Alvin J. Law",
"Daniel G. Aliaga",
"Aditi Majumder"
] | [] | [] | [] |
Vis | 2,010 | Result-Driven Exploration of Simulation Parameter Spaces for Visual Effects Design | 10.1109/TVCG.2010.190 | Graphics artists commonly employ physically-based simulation for the generation of effects such as smoke, explosions, and similar phenomena. The task of finding the correct parameters for a desired result, however, is difficult and time-consuming as current tools provide little to no guidance. In this paper, we present a new approach for the visual exploration of such parameter spaces. Given a three-dimensional scene description, we utilize sampling and spatio-temporal clustering techniques to generate a concise overview of the achievable variations and their temporal evolution. Our visualization system then allows the user to explore the simulation space in a goal-oriented manner. Animation sequences with a set of desired characteristics can be composed using a novel search-by-example approach and interactive direct volume rendering is employed to provide instant visual feedback. | false | false | [
"Stefan Bruckner",
"Torsten Möller"
] | [] | [] | [] |
Vis | 2,010 | Scalable Multi-variate Analytics of Seismic and Satellite-based Observational Data | 10.1109/TVCG.2010.192 | Over the past few years, large human populations around the world have been affected by an increase in significant seismic activities. For both conducting basic scientific research and for setting critical government policies, it is crucial to be able to explore and understand seismic and geographical information obtained through all scientific instruments. In this work, we present a visual analytics system that enables explorative visualization of seismic data together with satellite-based observational data, and introduce a suite of visual analytical tools. Seismic and satellite data are integrated temporally and spatially. Users can select temporal ;and spatial ranges to zoom in on specific seismic events, as well as to inspect changes both during and after the events. Tools for designing high dimensional transfer functions have been developed to enable efficient and intuitive comprehension of the multi-modal data. Spread-sheet style comparisons are used for data drill-down as well as presentation. Comparisons between distinct seismic events are also provided for characterizing event-wise differences. Our system has been designed for scalability in terms of data size, complexity (i.e. number of modalities), and varying form factors of display environments. | false | false | [
"Xiaoru Yuan",
"He Xiao",
"Hanqi Guo 0001",
"Peihong Guo",
"Wesley Kendall",
"Jian Huang 0007",
"Yongxian Zhang"
] | [] | [] | [] |
Vis | 2,010 | Spatial Conditioning of Transfer Functions Using Local Material Distributions | 10.1109/TVCG.2010.195 | In many applications of Direct Volume Rendering (DVR) the importance of a certain material or feature is highly dependent on its relative spatial location. For instance, in the medical diagnostic procedure, the patient's symptoms often lead to specification of features, tissues and organs of particular interest. One such example is pockets of gas which, if found inside the body at abnormal locations, are a crucial part of a diagnostic visualization. This paper presents an approach that enhances DVR transfer function design with spatial localization based on user specified material dependencies. Semantic expressions are used to define conditions based on relations between different materials, such as only render iodine uptake when close to liver. The underlying methods rely on estimations of material distributions which are acquired by weighing local neighborhoods of the data against approximations of material likelihood functions. This information is encoded and used to influence rendering according to the user's specifications. The result is improved focus on important features by allowing the user to suppress spatially less-important data. In line with requirements from actual clinical DVR practice, the methods do not require explicit material segmentation that would be impossible or prohibitively time-consuming to achieve in most real cases. The scheme scales well to higher dimensions which accounts for multi-dimensional transfer functions and multivariate data. Dual-Energy Computed Tomography, an important new modality in radiology, is used to demonstrate this scalability. In several examples we show significantly improved focus on clinically important aspects in the rendered images. | false | false | [
"Stefan Lindholm",
"Patric Ljung",
"Claes Lundström",
"Anders Persson",
"Anders Ynnerman"
] | [] | [] | [] |
Vis | 2,010 | Special Relativistic Visualization by Local Ray Tracing | 10.1109/TVCG.2010.196 | Special relativistic visualization offers the possibility of experiencing the optical effects of traveling near the speed of light, including apparent geometric distortions as well as Doppler and searchlight effects. Early high-quality computer graphics images of relativistic scenes were created using offline, computationally expensive CPU-side 4D ray tracing. Alternate approaches such as image-based rendering and polygon-distortion methods are able to achieve interactivity, but exhibit inferior visual quality due to sampling artifacts. In this paper, we introduce a hybrid rendering technique based on polygon distortion and local ray tracing that facilitates interactive high-quality visualization of multiple objects moving at relativistic speeds in arbitrary directions. The method starts by calculating tight image-space footprints for the apparent triangles of the 3D scene objects. The final image is generated using a single image-space ray tracing step incorporating Doppler and searchlight effects. Our implementation uses GPU shader programming and hardware texture filtering to achieve high rendering speed. | false | false | [
"Thomas Müller 0005",
"Sebastian Grottel",
"Daniel Weiskopf"
] | [] | [] | [] |
Vis | 2,010 | Streak Lines as Tangent Curves of a Derived Vector field | 10.1109/TVCG.2010.198 | Characteristic curves of vector fields include stream, path, and streak lines. Stream and path lines can be obtained by a simple vector field integration of an autonomous ODE system, i.e., they can be described as tangent curves of a vector field. This facilitates their mathematical analysis including the extraction of core lines around which stream or path lines exhibit swirling motion, or the computation of their curvature for every point in the domain without actually integrating them. Such a description of streak lines is not yet available, which excludes them from most of the feature extraction and analysis tools that have been developed in our community. In this paper, we develop the first description of streak lines as tangent curves of a derived vector field - the streak line vector field - and show how it can be computed from the spatial and temporal gradients of the flow map, i.e., a dense path line integration is required. We demonstrate the high accuracy of our approach by comparing it to solutions where the ground truth is analytically known and to solutions where the ground truth has been obtained using the classic streak line computation. Furthermore, we apply a number of feature extraction and analysis tools to the new streak line vector field including the extraction of cores of swirling streak lines and the computation of streak line curvature fields. These first applications foreshadow the large variety of possible future research directions based on our new mathematical description of streak lines. | false | false | [
"Tino Weinkauf",
"Holger Theisel"
] | [
"BP"
] | [] | [] |
Vis | 2,010 | Superquadric Glyphs for Symmetric Second-Order Tensors | 10.1109/TVCG.2010.199 | Symmetric second-order tensor fields play a central role in scientific and biomedical studies as well as in image analysis and feature-extraction methods. The utility of displaying tensor field samples has driven the development of visualization techniques that encode the tensor shape and orientation into the geometry of a tensor glyph. With some exceptions, these methods work only for positive-definite tensors (i.e. having positive eigenvalues, such as diffusion tensors). We expand the scope of tensor glyphs to all symmetric second-order tensors in two and three dimensions, gracefully and unambiguously depicting any combination of positive and negative eigenvalues. We generalize a previous method of superquadric glyphs for positive-definite tensors by drawing upon a larger portion of the superquadric shape space, supplemented with a coloring that indicates the tensor's quadratic form. We show that encoding arbitrary eigenvalue sign combinations requires design choices that differ fundamentally from those in previous work on traceless tensors (arising in the study of liquid crystals). Our method starts with a design of 2-D tensor glyphs guided by principles of symmetry and continuity, and creates 3-D glyphs that include the 2-D glyphs in their axis-aligned cross-sections. A key ingredient of our method is a novel way of mapping from the shape space of three-dimensional symmetric second-order tensors to the unit square. We apply our new glyphs to stress tensors from mechanics, geometry tensors and Hessians from image analysis, and rate-of-deformation tensors in computational fluid dynamics. | false | false | [
"Thomas Schultz 0001",
"Gordon L. Kindlmann"
] | [] | [] | [] |
Vis | 2,010 | Supine and Prone Colon Registration Using Quasi-Conformal Mapping | 10.1109/TVCG.2010.200 | In virtual colonoscopy, CT scans are typically acquired with the patient in both supine (facing up) and prone (facing down) positions. The registration of these two scans is desirable so that the user can clarify situations or confirm polyp findings at a location in one scan with the same location in the other, thereby improving polyp detection rates and reducing false positives. However, this supine-prone registration is challenging because of the substantial distortions in the colon shape due to the patient's change in position. We present an efficient algorithm and framework for performing this registration through the use of conformal geometry to guarantee that the registration is a diffeomorphism (a one-to-one and onto mapping). The taeniae coli and colon flexures are automatically extracted for each supine and prone surface, employing the colon geometry. The two colon surfaces are then divided into several segments using the flexures, and each segment is cut along a taenia coli and conformally flattened to the rectangular domain using holomorphic differentials. The mean curvature is color encoded as texture images, from which feature points are automatically detected using graph cut segmentation, mathematic morphological operations, and principal component analysis. Corresponding feature points are found between supine and prone and are used to adjust the conformal flattening to be quasi-conformal, such that the features become aligned. We present multiple methods of visualizing our results, including 2D flattened rendering, corresponding 3D endoluminal views, and rendering of distortion measurements. We demonstrate the efficiency and efficacy of our registration method by illustrating matched views on both the 2D flattened colon images and in the 3D volume rendered colon endoluminal view. We analytically evaluate the correctness of the results by measuring the distance between features on the registered colons. | false | false | [
"Wei Zeng 0002",
"Joseph Marino",
"Krishna Chaitanya Gurijala",
"Xianfeng Gu",
"Arie E. Kaufman"
] | [] | [] | [] |
Vis | 2,010 | TanGeoMS: Tangible Geospatial Modeling System | 10.1109/TVCG.2010.202 | We present TanGeoMS, a tangible geospatial modeling visualization system that couples a laser scanner, projector, and a flexible physical three-dimensional model with a standard geospatial information system (GIS) to create a tangible user interface for terrain data. TanGeoMS projects an image of real-world data onto a physical terrain model. Users can alter the topography of the model by modifying the clay surface or placing additional objects on the surface. The modified model is captured by an overhead laser scanner then imported into a GIS for analysis and simulation of real-world processes. The results are projected back onto the surface of the model providing feedback on the impact of the modifications on terrain parameters and simulated processes. Interaction with a physical model is highly intuitive, allowing users to base initial design decisions on geospatial data, test the impact of these decisions in GIS simulations, and use the feedback to improve their design. We demonstrate the system on three applications: investigating runoff management within a watershed, assessing the impact of storm surge on barrier islands, and exploring landscape rehabilitation in military training areas. | false | false | [
"Laura Tateosian",
"Helena Mitásová",
"Brendan Harmon",
"Brent Fogleman",
"Katherine Weaver",
"Russell S. Harmon"
] | [] | [] | [] |
Vis | 2,010 | Two-Phase Mapping for Projecting Massive Data Sets | 10.1109/TVCG.2010.207 | Most multidimensional projection techniques rely on distance (dissimilarity) information between data instances to embed high-dimensional data into a visual space. When data are endowed with Cartesian coordinates, an extra computational effort is necessary to compute the needed distances, making multidimensional projection prohibitive in applications dealing with interactivity and massive data. The novel multidimensional projection technique proposed in this work, called Part-Linear Multidimensional Projection (PLMP), has been tailored to handle multivariate data represented in Cartesian high-dimensional spaces, requiring only distance information between pairs of representative samples. This characteristic renders PLMP faster than previous methods when processing large data sets while still being competitive in terms of precision. Moreover, knowing the range of variation for data instances in the high-dimensional space, we can make PLMP a truly streaming data projection technique, a trait absent in previous methods. | false | false | [
"Fernando Vieira Paulovich",
"Cláudio T. Silva",
"Luis Gustavo Nonato"
] | [] | [] | [] |
Vis | 2,010 | Uncertainty-Aware Guided Volume Segmentation | 10.1109/TVCG.2010.208 | Although direct volume rendering is established as a powerful tool for the visualization of volumetric data, efficient and reliable feature detection is still an open topic. Usually, a tradeoff between fast but imprecise classification schemes and accurate but time-consuming segmentation techniques has to be made. Furthermore, the issue of uncertainty introduced with the feature detection process is completely neglected by the majority of existing approaches.In this paper we propose a guided probabilistic volume segmentation approach that focuses on the minimization of uncertainty. In an iterative process, our system continuously assesses uncertainty of a random walker-based segmentation in order to detect regions with high ambiguity, to which the user's attention is directed to support the correction of potential misclassifications. This reduces the risk of critical segmentation errors and ensures that information about the segmentation's reliability is conveyed to the user in a dependable way. In order to improve the efficiency of the segmentation process, our technique does not only take into account the volume data to be segmented, but also enables the user to incorporate classification information. An interactive workflow has been achieved by implementing the presented system on the GPU using the OpenCL API. Our results obtained for several medical data sets of different modalities, including brain MRI and abdominal CT, demonstrate the reliability and efficiency of our approach. | false | false | [
"Jörg-Stefan Praßni",
"Timo Ropinski",
"Klaus H. Hinrichs"
] | [] | [] | [] |
Vis | 2,010 | VDVR: Verifiable Volume Visualization of Projection-Based Data | 10.1109/TVCG.2010.211 | Practical volume visualization pipelines are never without compromises and errors. A delicate and often-studied component is the interpolation of off-grid samples, where aliasing can lead to misleading artifacts and blurring, potentially hiding fine details of critical importance. The verifiable visualization framework we describe aims to account for these errors directly in the volume generation stage, and we specifically target volumetric data obtained via computed tomography (CT) reconstruction. In this case the raw data are the X-ray projections obtained from the scanner and the volume data generation process is the CT algorithm. Our framework informs the CT reconstruction process of the specific filter intended for interpolation in the subsequent visualization process, and this in turn ensures an accurate interpolation there at a set tolerance. Here, we focus on fast trilinear interpolation in conjunction with an octree-type mixed resolution volume representation without T-junctions. Efficient rendering is achieved by a space-efficient and locality-optimized representation, which can straightforwardly exploit fast fixed-function pipelines on GPUs. | false | false | [
"Ziyi Zheng",
"Wei Xu 0020",
"Klaus Mueller 0001"
] | [] | [] | [] |
Vis | 2,010 | View-Dependent Streamlines for 3D Vector fields | 10.1109/TVCG.2010.212 | This paper introduces a new streamline placement and selection algorithm for 3D vector fields. Instead of considering the problem as a simple feature search in data space, we base our work on the observation that most streamline fields generate a lot of self-occlusion which prevents proper visualization. In order to avoid this issue, we approach the problem in a view-dependent fashion and dynamically determine a set of streamlines which contributes to data understanding without cluttering the view. Since our technique couples flow characteristic criteria and view-dependent streamline selection we are able achieve the best of both worlds: relevant flow description and intelligible, uncluttered pictures. We detail an efficient GPU implementation of our algorithm, show comprehensive visual results on multiple datasets and compare our method with existing flow depiction techniques. Our results show that our technique greatly improves the readability of streamline visualizations on different datasets without requiring user intervention. | false | false | [
"Stéphane Marchesin",
"Cheng-Kai Chen",
"Chris Ho",
"Kwan-Liu Ma"
] | [] | [] | [] |
Vis | 2,010 | Visual Exploration of High Dimensional Scalar Functions | 10.1109/TVCG.2010.213 | An important goal of scientific data analysis is to understand the behavior of a system or process based on a sample of the system. In many instances it is possible to observe both input parameters and system outputs, and characterize the system as a high-dimensional function. Such data sets arise, for instance, in large numerical simulations, as energy landscapes in optimization problems, or in the analysis of image data relating to biological or medical parameters. This paper proposes an approach to analyze and visualizing such data sets. The proposed method combines topological and geometric techniques to provide interactive visualizations of discretely sampled high-dimensional scalar fields. The method relies on a segmentation of the parameter space using an approximate Morse-Smale complex on the cloud of point samples. For each crystal of the Morse-Smale complex, a regression of the system parameters with respect to the output yields a curve in the parameter space. The result is a simplified geometric representation of the Morse-Smale complex in the high dimensional input domain. Finally, the geometric representation is embedded in 2D, using dimension reduction, to provide a visualization platform. The geometric properties of the regression curves enable the visualization of additional information about each crystal such as local and global shape, width, length, and sampling densities. The method is illustrated on several synthetic examples of two dimensional functions. Two use cases, using data sets from the UCI machine learning repository, demonstrate the utility of the proposed approach on real data. Finally, in collaboration with domain experts the proposed method is applied to two scientific challenges. The analysis of parameters of climate simulations and their relationship to predicted global energy flux and the concentrations of chemical species in a combustion simulation and their integration with temperature. | false | false | [
"Samuel Gerber",
"Peer-Timo Bremer",
"Valerio Pascucci",
"Ross T. Whitaker"
] | [] | [] | [] |
Vis | 2,010 | Visual Optimality and Stability Analysis of 3DCT Scan Positions | 10.1109/TVCG.2010.214 | Industrial cone-beam X-Ray computed tomography (CT) systems often face problems due to artifacts caused by a bad placement of the specimen on the rotary plate. This paper presents a visual-analysis tool for CT systems, which provides a simulation-based preview and estimates artifacts and deviations of a specimen's placement using the corresponding 3D geometrical surface model as input. The presented tool identifies potentially good or bad placements of a specimen and regions of a specimen, which cause the major portion of artefacts. The tool can be used for a preliminary analysis of the specimen before CT scanning, in order to determine the optimal way of placing the object. The analysis includes: penetration lengths, placement stability and an investigation in Radon space. Novel visualization techniques are applied to the simulation data. A stability widget is presented for determining the placement parameters' robustness. The performance and the comparison of results provided by the tool compared with real world data is demonstrated using two specimens. | false | false | [
"Artem Amirkhanov",
"Christoph Heinzl",
"Michael Reiter",
"M. Eduard Gröller"
] | [] | [] | [] |
Vis | 2,010 | Visualization by Proxy: A Novel Framework for Deferred Interaction with Volume Data | 10.1109/TVCG.2010.215 | Interactivity is key to exploration of volume data. Interactivity may be hindered due to many factors, e.g. large data size,high resolution or complexity of a data set, or an expensive rendering algorithm. We present a novel framework for visualizing volumedata that enables interactive exploration using proxy images, without accessing the original 3D data. Data exploration using directvolume rendering requires multiple (often redundant) accesses to possibly large amounts of data. The notion of visualization by proxyrelies on the ability to defer operations traditionally used for exploring 3D data to a more suitable intermediate representation forinteraction - proxy images. Such operations include view changes, transfer function exploration, and relighting. While previous workhas addressed specific interaction needs, we provide a complete solution that enables real-time interaction with large data sets andhas low hardware and storage requirements. | false | false | [
"Anna Tikhonova",
"Carlos D. Correa",
"Kwan-Liu Ma"
] | [] | [] | [] |
Vis | 2,010 | Visualizing Flow Trajectories Using Locality-based Rendering and Warped Curve Plots | 10.1109/TVCG.2010.218 | In flow simulations the behavior and properties of particle trajectories often depend on the physical geometry contained in the simulated environment. Understanding the flow in and around the geometry itself is an important part of analyzing the data. Previous work has often utilized focus+context rendering techniques, with an emphasis on showing trajectories while simplifying or illustratively rendering the physical areas. Our research instead emphasizes the local relationship between particle paths and geometry by using a projected multi-field visualization technique. The correlation between a particle path and its surrounding area is calculated on-the-fly and displayed in a non-intrusive manner. In addition, we support visual exploration and comparative analysis through the use of linked information visualization, such as manipulatable curve plots and one-on-one similarity plots. Our technique is demonstrated on particle trajectories from a groundwater simulation and a computer room airflow simulation, where the flow of particles is highly influenced by the dense geometry. | false | false | [
"Chad Jones",
"Kwan-Liu Ma"
] | [] | [] | [] |
Vis | 2,010 | Volumetric Modeling in Laser BPH Therapy Simulation | 10.1109/TVCG.2010.221 | In this paper, we introduce a novel application of volume modeling techniques on laser Benign Prostatic Hyperplasia (BPH) therapy simulation. The core technique in our system is an algorithm for simulating the tissue vaporization process by laser heating. Different from classical volume CSG operations, our technique takes experimental data as the guidance to determine the vaporization amount so that only a specified amount of tissue is vaporized in each time. Our algorithm uses a predictor-corrector strategy. First, we apply the classical CSG algorithm on a tetrahedral grid based distance field to estimate the vaporized tissue amount. Then, a volume-correction phase is applied on the distance field. To improve the performance, we further propose optimization approaches for efficient implementation. | false | false | [
"Nan Zhang",
"Xiangmin Zhou",
"Yunhe Shen",
"Robert M. Sweet"
] | [] | [] | [] |
Vis | 2,010 | World Lines | 10.1109/TVCG.2010.223 | In this paper we present World Lines as a novel interactive visualization that provides complete control over multiple heterogeneous simulation runs. In many application areas, decisions can only be made by exploring alternative scenarios. The goal of the suggested approach is to support users in this decision making process. In this setting, the data domain is extended to a set of alternative worlds where only one outcome will actually happen. World Lines integrate simulation, visualization and computational steering into a single unified system that is capable of dealing with the extended solution space. World Lines represent simulation runs as causally connected tracks that share a common time axis. This setup enables users to interfere and add new information quickly. A World Line is introduced as a visual combination of user events and their effects in order to present a possible future. To quickly find the most attractive outcome, we suggest World Lines as the governing component in a system of multiple linked views and a simulation component. World Lines employ linking and brushing to enable comparative visual analysis of multiple simulations in linked views. Analysis results can be mapped to various visual variables that World Lines provide in order to highlight the most compelling solutions. To demonstrate this technique we present a flooding scenario and show the usefulness of the integrated approach to support informed decision making. | false | false | [
"Jürgen Waser",
"Raphael Fuchs",
"Hrvoje Ribicic",
"Benjamin Schindler",
"Günter Blöschl",
"M. Eduard Gröller"
] | [
"HM"
] | [] | [] |
VAST | 2,010 | A closer look at note taking in the co-located collaborative visual analytics process | 10.1109/VAST.2010.5652879 | This paper highlights the important role that record-keeping (i.e. taking notes and saving charts) plays in collaborative data analysis within the business domain. The discussion of record-keeping is based on observations from a user study in which co-located teams worked on collaborative visual analytics tasks using large interactive wall and tabletop displays. Part of our findings is a collaborative data analysis framework that encompasses note taking as one of the main activities. We observed that record-keeping was a critical activity within the analysis process. Based on our observations, we characterize notes according to their content, scope, and usage, and describe how they fit into a process of collaborative data analysis. We then discuss suggestions for the design of collaborative visual analytics tools. | false | false | [
"Narges Mahyar",
"Ali Sarvghad",
"Melanie Tory"
] | [] | [] | [] |
VAST | 2,010 | A continuous analysis process between desktop and collaborative visual analytics environments | 10.1109/VAST.2010.5652958 | Since its inception, the field of visual analytics has undergone tremendous growth in understanding how to create interactive visual tools to solve analytical problems. However, with few exceptions, most of these tools have been designed for single users in desktop environments. While often effective on their own, most single-user systems do not reflect the collaborative nature of solving real-world analytical tasks. Many intelligence analysts, for example, have been observed to switch repeatedly between working alone and collaborating with members of a small team. In this paper, we propose that a complete visual analytical system designed for solving real-world tasks ought to have two integrated components: a single-user desktop system and a mirroring system suitable for a collaborative environment. | false | false | [
"Dong Hyun Jeong",
"Evan A. Suma",
"Thomas Butkiewicz",
"William Ribarsky",
"Remco Chang"
] | [] | [] | [] |
VAST | 2,010 | A radial visualization tool for depicting hierarchically structured video content | 10.1109/VAST.2010.5650177 | The visual analysis of video content is an important research topic due to the huge amount of video data that is generated every day. Annotating this data will become a major problem since the amount of videos further increases. With this work we introduce a system that combines a visualization tool with automatic video segmentation techniques and a characteristic key-frame extraction. A summary of the content of a whole video in one view is realized. Furthermore, the user can interactively browse through the video via our visualization interface to get more detailed information. The system is adapted to two application scenarios and a third application is discussed for future work. | false | false | [
"Tobias Ruppert",
"Jörn Kohlhammer"
] | [] | [] | [] |
VAST | 2,010 | A Visual Analytics approach to identifying protein structural constraints | 10.1109/VAST.2010.5650199 | Predicting protein structures has long been a grand-challenge problem. Fine-grained computational simulation of folding events from a protein's synthesis to its final stable structure remains computationally intractable. Therefore, methods which derive constraints from other sources are attractive. To date, constraints derived from known structures have proven to be highly successful. However, these cannot be applied to molecules with no identifiable neighbors having already-determined structures. For such molecules, structural constraints must be derived in other ways. One popular approach has been the statistical analysis of large families of proteins, with the hope that residues that “change together” (co-evolve) imply that those residues are in contact. Unfortunately, despite repeated attempts to use this data to deduce structural constraints, this approach has met with minimal success. The consensus of current literature concludes that there is simply too little information contained within the correlated mutations of many protein families to reliably and generally predict structural constraints. Recent work in my laboratory challenges this conclusion. For some time we have been developing methods (MAVL/StickWRLD) to visualize the pattern of co-evolved mutations within sequence families. While our analysis of individual correlations agrees with the literature consensus, we have recently discovered that the visualized pattern of correlations is highly suggestive of structural relationships. In our preliminary test cases, human researchers can unambiguously determine many positive structural constraints by visual analysis of statistical sequence information alone, often with no training on interpretation of the visualization results. Herein we report the visualization design that supports this Visual Analytics approach to identifying high-confidence hypotheses about protein folding from protein sequence, and illustrate preliminary results from this research. Our approach entails a higher-dimensional extension of parallel coordinates which illuminates distant shared sub-tuples of the vectors representing each protein sequence when these sub-tuples occur with an over abundance compared to expectations. It simultaneously eliminates all representations of tuples which occur with frequency near the expected norm. The result is a minimally-occluded representation of outlier, and only outlier co-occurrences within the sequence families. | false | false | [
"William C. Ray"
] | [] | [] | [] |
VAST | 2,010 | A visual analytics approach to model learning | 10.1109/VAST.2010.5652484 | The process of learning models from raw data typically requires a substantial amount of user input during the model initialization phase. We present an assistive visualization system which greatly reduces the load on the users and makes the process of model initialization and refinement more efficient, problem-driven, and engaging. Utilizing a sequence segmentation task with a Hidden Markov Model as an example, we assign each token in the sequence a feature vector based on its various properties within the sequence. These vectors are then clustered according to similarity, generating a layout of the individual tokens in form of a node link diagram where the length of the links is determined by the feature vector similarity. Users may then tune the weights of the feature vector components to improve the segmentation, which is visualized as a better separation of the clusters. Also, as individual clusters represent different classes, the user can now work at the cluster level to define token classes, instead of labelling one entry at time. Inconsistent entries visually identify themselves by locating at the periphery of clusters, and the user then helps refine the model by resolving these inconsistencies. Our system therefore makes efficient use of the knowledge of its users, only requesting user assistance for non-trivial data items. It so allows users to visually analyse data at a higher, more abstract level, improving scalability. | false | false | [
"Supriya Garg",
"I. V. Ramakrishnan",
"Klaus Mueller 0001"
] | [] | [] | [] |
VAST | 2,010 | Adapting Daniel and Wood's modeling approach to interactive visual analytics | 10.1109/VAST.2010.5649831 | This poster describes our progress in developing an interactive linear modeling system that supports the modeling approach described by Daniel and Wood. Our visual interface permits analysts to build sets of possible models and then creates appropriate visualizations to permit human-in-the-loop model comparison and selection. | false | false | [
"Justin Talbot",
"Pat Hanrahan"
] | [] | [] | [] |
VAST | 2,010 | ALIDA: Using machine learning for intent discernment in visual analytics interfaces | 10.1109/VAST.2010.5650854 | In this paper, we introduce ALIDA, an Active Learning Intent Discerning Agent for visual analytics interfaces. As users interact with and explore data in a visual analytics environment they are each developing their own unique analytic process. The goal of ALIDA is to observe and record the human-computer interactions and utilize these observations as a means of supporting user exploration; ALIDA does this by using interaction to make decision about user interest. As such, ALIDA is designed to track the decision history (interactions) of a user. This history is then utilized to enhance the user's decision-making process by allowing the user to return to previously visited search states, as well as providing suggestions of other search states that may be of interest based on past exploration modalities. The agent passes these suggestions (or decisions) back to an interactive visualization prototype, and these suggestions are used to guide the user, either by suggesting searches or changes to the visualization view. Current work has tested ALIDA under the exploration of homonyms for users wishing to explore word linkages within a dictionary. Ongoing work includes using ALIDA to guide users in transfer function design for volume rendering within scientific gateways. | false | false | [
"Tera Marie Green",
"Ross Maciejewski",
"Steve DiPaola"
] | [] | [] | [] |
VAST | 2,010 | An exploratory study of co-located collaborative visual analytics around a tabletop display | 10.1109/VAST.2010.5652880 | Co-located collaboration can be extremely valuable during complex visual analytics tasks. This paper presents an exploratory study of a system designed to support collaborative visual analysis tasks on a digital tabletop display. Fifteen participant pairs employed Cam-biera, a visual analytics system, to solve a problem involving 240 digital documents. Our analysis, supported by observations, system logs, questionnaires, and interview data, explores how pairs approached the problem around the table. We contribute a unique, rich understanding of how users worked together around the table and identify eight types of collaboration styles that can be used to identify how closely people work together while problem solving. We show how the closeness of teams' collaboration influenced how well they performed on the task overall. We further discuss the role of the tabletop for visual analytics tasks and derive novel design implications for future co-located collaborative tabletop problem solving systems. | false | false | [
"Petra Isenberg",
"Danyel Fisher",
"Meredith Ringel Morris",
"Kori Inkpen",
"Mary Czerwinski"
] | [
"HM"
] | [] | [] |
VAST | 2,010 | Anomaly detection in GPS data based on visual analytics | 10.1109/VAST.2010.5652467 | Modern machine learning techniques provide robust approaches for data-driven modeling and critical information extraction, while human experts hold the advantage of possessing high-level intelligence and domain-specific expertise. We combine the power of the two for anomaly detection in GPS data by integrating them through a visualization and human-computer interaction interface. In this paper we introduce GPSvas (GPS Visual Analytics System), a system that detects anomalies in GPS data using the approach of visual analytics: a conditional random field (CRF) model is used as the machine learning component for anomaly detection in streaming GPS traces. A visualization component and an interactive user interface are built to visualize the data stream, display significant analysis results (i.e., anomalies or uncertain predications) and hidden information extracted by the anomaly detection model, which enable human experts to observe the real-time data behavior and gain insights into the data flow. Human experts further provide guidance to the machine learning model through the interaction tools; the learning model is then incrementally improved through an active learning procedure. | false | false | [
"Zicheng Liao",
"Yizhou Yu",
"Baoquan Chen"
] | [] | [] | [] |
VAST | 2,010 | Click2Annotate: Automated Insight Externalization with rich semantics | 10.1109/VAST.2010.5652885 | Insight Externalization (IE) refers to the process of capturing and recording the semantics of insights in decision making and problem solving. To reduce human effort, Automated Insight Externalization (AIE) is desired. Most existing IE approaches achieve automation by capturing events (e.g., clicks and key presses) or actions (e.g., panning and zooming). In this paper, we propose a novel AIE approach named Click2Annotate. It allows semi-automatic insight annotation that captures low-level analytics task results (e.g., clusters and outliers), which have higher semantic richness and abstraction levels than actions and events. Click2Annotate has two significant benefits. First, it reduces human effort required in IE and generates annotations easy to understand. Second, the rich semantic information encoded in the annotations enables various insight management activities, such as insight browsing and insight retrieval. We present a formal user study that proved this first benefit. We also illustrate the second benefit by presenting the novel insight management activities we developed based on Click2Annotate, namely scented insight browsing and faceted insight search. | false | false | [
"Yang Chen",
"Scott Barlowe",
"Jing Yang 0001"
] | [] | [] | [] |
VAST | 2,010 | Cluster correspondence views for enhanced analysis of SOM displays | 10.1109/VAST.2010.5651676 | The Self-Organizing Map (SOM) algorithm is a popular and widely used cluster algorithm. Its constraint to organize clusters on a grid structure makes it very amenable to visualization. On the other hand, the grid constraint may lead to reduced cluster accuracy and reliability, compared to other clustering methods not implementing this restriction. We propose a visual cluster analysis system that allows to validate the output of the SOM algorithm by comparison with alternative clustering methods. Specifically, visual mappings overlaying alternative clustering results onto the SOM are proposed. We apply our system on an example data set, and outline main analytical use cases. | false | false | [
"Jürgen Bernard",
"Tatiana von Landesberger",
"Sebastian Bremm",
"Tobias Schreck"
] | [] | [] | [] |
VAST | 2,010 | Combining statistical independence testing, visual attribute selection and automated analysis to find relevant attributes for classification | 10.1109/VAST.2010.5654445 | We present an iterative strategy for finding a relevant subset of attributes for the purpose of classification in high-dimensional, heterogeneous data sets. The attribute subset is used for the construction of a classifier function. In order to cope with the challenge of scalability, the analysis is split into an overview of all attributes and a detailed analysis of small groups of attributes. The overview provides generic information on statistical dependencies between attributes. With this information the user can select groups of attributes and an analytical method for their detailed analysis. The detailed analysis involves the identification of redundant attributes (via classification or regression) and the creation of summarizing attributes (via clustering or dimension reduction). Our strategy does not prescribe specific analytical methods. Instead, we recursively combine the results of different methods to find or generate a subset of attributes to use for classification. | false | false | [
"Thorsten May",
"James Davey",
"Jörn Kohlhammer"
] | [] | [] | [] |
VAST | 2,010 | Comparing different levels of interaction constraints for deriving visual problem isomorphs | 10.1109/VAST.2010.5653599 | Interaction and manual manipulation have been shown in the cognitive science literature to play a critical role in problem solving. Given different types of interactions or constraints on interactions, a problem can appear to have different degrees of difficulty. While this relationship between interaction and problem solving has been well studied in the cognitive science literatures, the visual analytics community has yet to exploit this understanding for analytical problem solving. In this paper, we hypothesize that constraints on interactions and constraints encoded in visual representations can lead to strategies of varying effectiveness during problem solving. To test our hypothesis, we conducted a user study in which participants were given different levels of interaction constraints when solving a simple math game called Number Scrabble. Number Scrabble is known to have an optimal visual problem isomorph, and the goal of this study is to learn if and how the participants could derive the isomorph and to analyze the strategies that the participants utilize in solving the problem. Our results indicate that constraints on interactions do affect problem solving, and that while the optimal visual isomorph is difficult to derive, certain interaction constraints can lead to a higher chance of deriving the isomorph. | false | false | [
"Wenwen Dou",
"Caroline Ziemkiewicz",
"Lane Harrison",
"Dong Hyun Jeong",
"Roxanne Ryan",
"William Ribarsky",
"Derek Xiaoyu Wang",
"Remco Chang"
] | [] | [] | [] |
VAST | 2,010 | Conveying network features in geospatial battlespace displays | 10.1109/VAST.2010.5651192 | Advanced battlespace network visualization techniques are required within the modern Air Operations Center (AOC) to improve cross-domain situation awareness and to support planning and decision-making. We present a visualization toolkit to address this need that supports the integration of network health and status information and meta-information with other traditional AOC information resources and activities across air, space, and cyber domains. Applications include the development of battlespace visualization technologies that will improve warfighters' decision-making response time and provide enhanced flexibility for mission planning by efficiently revealing affordances for leveraging, disrupting, or enhancing network connectivity. | false | false | [
"J. Alex Godwin",
"Ryan M. Kilgore"
] | [] | [] | [] |
VAST | 2,010 | Data representation and exploration with Geometric Wavelets | 10.1109/VAST.2010.5653822 | Geometric Wavelets is a new multi-scale data representation technique which is useful for a variety of applications such as data compression, interpretation and anomaly detection. We have developed an interactive visualization with multiple linked views to help users quickly explore data sets and understand this novel construction. Currently the interface is being used by applied mathematicians to view results and gain new insights, speeding methods development. | false | false | [
"Eric E. Monson",
"Guangliang Chen",
"Rachel Brady",
"Mauro Maggioni"
] | [] | [] | [] |
VAST | 2,010 | Diamonds in the rough: Social media visual analytics for journalistic inquiry | 10.1109/VAST.2010.5652922 | Journalists increasingly turn to social media sources such as Facebook or Twitter to support their coverage of various news events. For large-scale events such as televised debates and speeches, the amount of content on social media can easily become overwhelming, yet still contain information that may aid and augment reporting via individual content items as well as via aggregate information from the crowd's response. In this work we present a visual analytic tool, Vox Civitas, designed to help journalists and media professionals extract news value from large-scale aggregations of social media content around broadcast events. We discuss the design of the tool, present the text analysis techniques used to enable the presentation, and provide details on the visual and interaction design. We provide an exploratory evaluation based on a user study in which journalists interacted with the system to explore and report on a dataset of over one hundred thousand twitter messages collected during the U.S. State of the Union presidential address in 2010. | false | false | [
"Nicholas Diakopoulos",
"Mor Naaman",
"Funda Kivran-Swaine"
] | [] | [] | [] |
VAST | 2,010 | DimStiller: Workflows for dimensional analysis and reduction | 10.1109/VAST.2010.5652392 | DimStiller is a system for dimensionality reduction and analysis. It frames the task of understanding and transforming input dimensions as a series of analysis steps where users transform data tables by chaining together different techniques, called operators, into pipelines of expressions. The individual operators have controls and views that are linked together based on the structure of the expression. Users interact with the operator controls to tune parameter choices, with immediate visual feedback guiding the exploration of local neighborhoods of the space of possible data tables. DimStiller also provides global guidance for navigating data-table space through expression templates called workflows, which permit re-use of common patterns of analysis. | false | false | [
"Stephen Ingram",
"Tamara Munzner",
"Veronika Irvine",
"Melanie Tory",
"Steven Bergner",
"Torsten Möller"
] | [] | [] | [] |
VAST | 2,010 | Discovering bits of place histories from people's activity traces | 10.1109/VAST.2010.5652478 | Events that happened in the past are important for understanding the ongoing processes, predicting future developments, and making informed decisions. Significant and/or interesting events tend to attract many people. Some people leave traces of their attendance in the form of computer-processable data, such as records in the databases of mobile phone operators or photos on photo sharing web sites. We developed a suite of visual analytics methods for reconstructing past events from these activity traces. Our tools combine geocomputations, interactive geovisualizations and statistical methods to enable integrated analysis of the spatial, temporal, and thematic components of the data, including numeric attributes and texts. We demonstrate the utility of our approach on two large real data sets, mobile phone calls in Milano during 9 days and flickr photos made on British Isles during 5 years. | false | false | [
"Gennady L. Andrienko",
"Natalia V. Andrienko",
"Martin Mladenov",
"Michael Mock",
"Christian Pölitz"
] | [
"HM"
] | [] | [] |
VAST | 2,010 | EmailTime: Visual analytics of emails | 10.1109/VAST.2010.5652968 | Although the discovery and analysis of communication patterns in large and complex email datasets are difficult tasks, they can be a valuable source of information. This paper presents EmailTime's capabilities through several examples. EmailTime is a visual analysis of email correspondence patterns over the course of time that interactively portrays personal and interpersonal networks using the correspondence in the email dataset. We suggest that integrating both statistics and visualizations in order to display information about the email datasets may simplify its evaluation. | false | false | [
"Minoo Erfani Joorabchi",
"Ji-Dong Yim",
"Chris Shaw 0002"
] | [] | [] | [] |
VAST | 2,010 | Enhancing text-based chat with visuals for hazardous weather decision making | 10.1109/VAST.2010.5650815 | We created a visual chat application for use during hazardous weather events. The application, NWSChat2, allows National Weather Service forecasters, media members, and storm trackers to communicate with each other, basing their conversation on a common shared radar map of the storm. Users can additionally annotate the map with `pins' or draw notes with a stylus. These annotations are automatically shared with all other users. The collaborative nature of NWSChat2 makes it well-suited for disseminating information to all users during weather emergencies. | false | false | [
"Moshe Gutman",
"Gina Eosco",
"Monica Zappa",
"Chris E. Weaver"
] | [] | [] | [] |
VAST | 2,010 | Enron case study: Analysis of email behavior using EmailTime | 10.1109/VAST.2010.5649905 | This paper presents a case study with Enron email dataset to explore the behaviors of email users within different organizational positions. We defined email behavior as the email activity level of people regarding a series of measured metrics e.g. sent and received emails, numbers of email addresses, etc. These metrics were calculated through EmailTime, a visual analysis tool of email correspondence over the course of time. Results showed specific patterns in the email datasets of different organizational positions. | false | false | [
"Minoo Erfani Joorabchi",
"Ji-Dong Yim",
"Mona Erfani Joorabchi",
"Chris Shaw 0002"
] | [] | [] | [] |
VAST | 2,010 | finding and visualizing relevant subspaces for clustering high-dimensional astronomical data using connected morphological operators | 10.1109/VAST.2010.5652450 | Data sets in astronomy are growing to enormous sizes. Modern astronomical surveys provide not only image data but also catalogues of millions of objects (stars, galaxies), each object with hundreds of associated parameters. Exploration of this very high-dimensional data space poses a huge challenge. Subspace clustering is one among several approaches which have been proposed for this purpose in recent years. However, many clustering algorithms require the user to set a large number of parameters without any guidelines. Some methods also do not provide a concise summary of the datasets, or, if they do, they lack additional important information such as the number of clusters present or the significance of the clusters. In this paper, we propose a method for ranking subspaces for clustering which overcomes many of the above limitations. First we carry out a transformation from parametric space to discrete image space where the data are represented by a grid-based density field. Then we apply so-called connected morphological operators on this density field of astronomical objects that provides visual support for the analysis of the important subspaces. Clusters in subspaces correspond to high-intensity regions in the density image. The importance of a cluster is measured by a new quality criterion based on the dynamics of local maxima of the density. Connected operators are able to extract such regions with an indication of the number of clusters present. The subspaces are visualized during computation of the quality measure, so that the user can interact with the system to improve the results. In the result stage, we use three visualization toolkits linked within a graphical user interface so that the user can perform an in-depth exploration of the ranked subspaces. Evaluation based on synthetic as well as real astronomical datasets demonstrates the power of the new method. We recover various known astronomical relations directly from the data with little or no a priori assumptions. Hence, our method holds good prospects for discovering new relations as well. | false | false | [
"Bilkis J. Ferdosi",
"Hugo Buddelmeijer",
"Scott C. Trager",
"Michael H. F. Wilkinson",
"Jos B. T. M. Roerdink"
] | [] | [] | [] |
VAST | 2,010 | Flow-based scatterplots for sensitivity analysis | 10.1109/VAST.2010.5652460 | Visualization of multi-dimensional data is challenging due to the number of complex correlations that may be present in the data but that are difficult to be visually identified. One of the main causes for this problem is the inherent loss of information that occurs when high-dimensional data is projected into 2D or 3D. Although 2D scatterplots are ubiquitous due to their simplicity and familiarity, there are not a lot of variations on their basic metaphor. In this paper, we present a new way of visualizing multidimensional data using scatterplots. We extend 2D scatterplots using sensitivity coefficients to highlight local variation of one variable with respect to another. When applied to a scatterplot, these sensitivities can be understood as velocities, and the resulting visualization resembles a flow field. We also present a number of operations, based on flow-field analysis, that help users navigate, select and cluster points in an efficient manner. We show the flexibility and generality of this approach using a number of multidimensional data sets across different domains. | false | false | [
"Yu-Hsuan Chan",
"Carlos D. Correa",
"Kwan-Liu Ma"
] | [] | [] | [] |
VAST | 2,010 | Geo-historical context support for information foraging and sensemaking: Conceptual model, implementation, and assessment | 10.1109/VAST.2010.5652895 | Information foraging and sensemaking with heterogeneous information are context-dependent activities. Thus visual analytics tools to support these activities must incorporate context. But, context is a difficult concept to define, model, and represent. Creating and representing context in support of visually-enabled reasoning about complex problems with complex information is a complementary but different challenge than that addressed in context-aware computing. In the latter, the goal is automated adaptation of the system to meet user needs for applications such as mobile location-based services where information about the location, the user, and the user goals filters what gets presented on a small mobile device. In contrast, for visual analytics-enabled information foraging and sensemaking, the user is likely to take an active role in foraging for the contextual information needed to support sensemaking in relation to some multifaceted problem. In this paper, we address the challenges of constructing and representing context within visual interfaces that support analytical reasoning in crisis management and humanitarian relief. The challenges stem from the diverse forms of information that can provide context and difficulty in defining and operationalizing context itself. Here, we pay particular attention to document foraging to support construction of the geographic and historical context within which monitoring and sensemaking can be carried out. Specifically, we present the concept of geo-historical context (GHC) and outline an empirical assessment of both the concept and its implementation in the Context Discovery Application, a web-based tool that supports document foraging and sensemaking. | false | false | [
"Brian M. Tomaszewski",
"Alan M. MacEachren"
] | [] | [] | [] |
VAST | 2,010 | Helping users recall their reasoning process | 10.1109/VAST.2010.5653598 | The final product of an analyst's investigation using a visualization is often a report of the discovered knowledge, as well as the methods employed and reasoning behind the discovery. We believe that analysts may have difficulty keeping track of their knowledge discovery process and will require tools to assist in accurately recovering their reasoning. We first report on a study examining analysts' recall of their strategies and methods, demonstrating their lack of memory of the path of knowledge discovery. We then explore whether a tool visualizing the steps of the visual analysis can aid users in recalling their reasoning process. The results of our second study indicate that visualizations of interaction logs can serve as an effective memory aid, allowing analysts to recall additional details of their strategies and decisions. | false | false | [
"Heather Lipford",
"Felesia Stukes",
"Wenwen Dou",
"Matthew E. Hawkins",
"Remco Chang"
] | [] | [] | [] |
VAST | 2,010 | Improving the visual analysis of high-dimensional datasets using quality measures | 10.1109/VAST.2010.5652433 | Modern visualization methods are needed to cope with very high-dimensional data. Efficient visual analytical techniques are required to extract the information content in these data. The large number of possible projections for each method, which usually grow quadrat-ically or even exponentially with the number of dimensions, urges the necessity to employ automatic reduction techniques, automatic sorting or selecting the projections, based on their information-bearing content. Different quality measures have been successfully applied for several specified user tasks and established visualization techniques, like Scatterplots, Scatterplot Matrices or Parallel Coordinates. Many other popular visualization techniques exist, but due to the structural differences, the measures are not directly applicable to them and new approaches are needed. In this paper we propose new quality measures for three popular visualization methods: Radviz, Pixel-Oriented Displays and Table Lenses. Our experiments show that these measures efficiently guide the visual analysis task. | false | false | [
"Georgia Albuquerque",
"Martin Eisemann",
"Dirk J. Lehmann",
"Holger Theisel",
"Marcus A. Magnor"
] | [] | [] | [] |
VAST | 2,010 | Interactive querying of temporal data using a comic strip metaphor | 10.1109/VAST.2010.5652890 | Finding patterns in temporal data is an important data analysis task in many domains. Static visualizations can help users easily see certain instances of patterns, but are not specially designed to support systematic analysis tasks, such as finding all instances of a pattern automatically. VizPattern is an interactive visual query environment that uses a comic strip metaphor to enable users to easily and quickly define and locate complex temporal patterns. Evaluations provide evidence that VizPattern is applicable in many domains, and that it enables a wide variety of users to answer questions about temporal data faster and with fewer errors than existing state-of-the-art visual analysis systems. | false | false | [
"Jing Jin",
"Pedro A. Szekely"
] | [] | [] | [] |
VAST | 2,010 | Interactive visual analysis of multiobjective optimizations | 10.1109/VAST.2010.5651694 | Optimization problems are typically addressed by purely automatic approaches. For multi-objective problems, however, a single best solution often does not exist. In this case, it is necessary to analyze trade-offs between many conflicting goals within a given application context. This poster describes an approach that tightly integrates automatic algorithms for multi-objective optimization and interactive multivariate visualizations. Ad-hoc selections support a flexible definition of input data for subsequent algorithms. These algorithms in turn represent their result as derived data attributes that can be assigned to visualizations or be used as a basis for further selections (e.g., to constrain the result set). This enables a guided search that still involves the knowledge of domain experts. We describe our approach in the context of multi-run simulation data from the application domain of car engine design. | false | false | [
"Wolfgang Berger",
"Harald Piringer"
] | [] | [] | [] |
VAST | 2,010 | iVisClassifier: An interactive visual analytics system for classification based on supervised dimension reduction | 10.1109/VAST.2010.5652443 | We present an interactive visual analytics system for classification, iVisClassifier, based on a supervised dimension reduction method, linear discriminant analysis (LDA). Given high-dimensional data and associated cluster labels, LDA gives their reduced dimensional representation, which provides a good overview about the cluster structure. Instead of a single two- or three-dimensional scatter plot, iVisClassifier fully interacts with all the reduced dimensions obtained by LDA through parallel coordinates and a scatter plot. Furthermore, it significantly improves the interactivity and interpretability of LDA. LDA enables users to understand each of the reduced dimensions and how they influence the data by reconstructing the basis vector into the original data domain. By using heat maps, iVisClassifier gives an overview about the cluster relationship in terms of pairwise distances between cluster centroids both in the original space and in the reduced dimensional space. Equipped with these functionalities, iVisClassifier supports users' classification tasks in an efficient way. Using several facial image data, we show how the above analysis is performed. | false | false | [
"Jaegul Choo",
"Hanseung Lee",
"Jaeyeon Kihm",
"Haesun Park"
] | [
"TT"
] | [] | [] |
VAST | 2,010 | Large-scale neuroanatomical visualization using a manifold embedding approach | 10.1109/VAST.2010.5652532 | We present a unified framework for data processing, mining and interactive visualization of large-scale neuroanatomical databases. The input data is assumed to lie in a specific atlas space, or simply exist as a separate collection. Users can specify their own atlas for comparative analyses. The original data exist as MRI images in standard formats. It is uploaded to a remote server and processed offline by a parallelized pipeline workflow. This workflow transforms the data to represent it as both volumetric and triangular mesh cortical surfaces. We use multiresolution representations to scale complexity to data storage availability as well as graphical processing performance. Our workflow implements predefined metrics for clustering and classification, and data projection schemes to aid in visualization. Additionally the system provides a visual query interface for performing selection requests based on user-defined search criteria. | false | false | [
"Shantanu H. Joshi",
"Ian Bowman",
"John D. Van Horn"
] | [] | [] | [] |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.