Übersicht
Geben Sie einen Suchbegriff ein oder verwenden Sie die Erweiterte Suche um nach Autor, Erscheinungsjahr oder Dokumenttyp zu filtern.
-
(2022) : Pi - Das Wunder dieser Zahl In: Forster, Michael; Alt, Sharon; Hanselmann, Marcel; Deflorin, Patricia (Hg.): Digitale Transformation an der Fachhochschule Graubünden: Case Studies aus Forschung und Lehre: Chur: FH Graubünden Verlag, S. 111-118. Online verfügbar unter https://www.fhgr.ch/fh-graubuenden/ueber-die-fh-graubuenden/wofuer-stehen-wir/digitalisierung/digitalisierungswissen-fuer-graubuenden/#c15147, zuletzt geprüft am 20.01.2023
Abstract: Das Ziel in diesem Projekt war es, sich mit der praktischen Umsetzung von High Performance Computing und der Visualisierung von grossen Datenmengen vertraut zu machen. Zu diesem Zweck hat das Team die Zahl Pi auf eine Präzision von 62.8 Billionen Stellen berechnet. In einem weiteren Schritt haben wir in dieser Zahl nach Mustern gesucht, welche wir danach visualisiert haben.
-
(2021) : A Web-Based Eye Tracking Data Visualization Tool In: Del Bimbo, Alberto; Cucchiara, Rita; Sclaroff, Stan; Farinella, Giovanni Maria; Mei, Tao; Bertini, Marco; Escalante, Hugo Jair; Vezzani, Roberto (Hg.): Pattern Recognition: ICPR International Workshops and Challenges: Proceedings. Part III: International Conference on Pattern Recognition (ICPR): Online, 10. - 15. Januar: Cham: Springer (Lecture Notes in Computer Science), S. 405-419
DOI: https://doi.org/10.1007/978-3-030-68796-0_29 Abstract: Visualizing eye tracking data can provide insights in many research fields. However, visualizing such data efficiently and cost-effectively is challenging without well-designed tools. Easily accessible web-based approaches equipped with intuitive and interactive visualizations offer to be a promising solution. Many of such tools already exist, however, they mostly use one specific visualization technique. In this paper, we describe a web application which uses a combination of different visualization methods for eye tracking data. The visualization techniques are interactively linked to provide several perspectives on the eye tracking data. We conclude the paper by discussing challenges, limitations, and future work.
-
(2021): The State of the Art in Empirical User Evaluation of Graph Visualizations. In: IEEE Access 9, S. 4173-4198. Online verfügbar unter https://doi.org/10.1109/ACCESS.2020.3047616, zuletzt geprüft am 03.09.2021
Abstract: While graph drawing focuses more on the aesthetic representation of node-link diagrams, graph visualization takes into account other visual metaphors making them useful for graph exploration tasks in information visualization and visual analytics. Although there are aesthetic graph drawing criteria that describe how a graph should be presented to make it faster and more reliably explorable, many controlled and uncontrolled empirical user studies flourished over the past years. The goal of them is to uncover how well the human user performs graph-specific tasks, in many cases compared to previously designed graph visualizations. Due to the fact that many parameters in a graph dataset as well as the visual representation of them might be varied and many user studies have been conducted in this space, a state-of-the-art survey is needed to understand evaluation results and findings to inform the future design, research, and application of graph visualizations. In this article, we classify the present literature on the topmost level into graph interpretation, graph memorability, and graph creation where the users with their tasks stand in focus of the evaluation, not the computational aspects. As another outcome of this work, we identify the white spots in this field and sketch ideas for future research directions.
-
(2021) : The Power of Linked Eye Movement Data Visualizations In: Bulling, Andreas; Huckauf, Anke; Gellersen, Hans; Weiskopf, Daniel; Bace, Mihai; Hirzle, Teresa; Alt, Florian; Pfeiffer, Thies; Bednarik, Roman; Krejtz, Krzysztof; Blascheck, Tanja; Burch, Michael; Kiefer, Peter; Dodd, Michael D.; Sharif, Bonita (Hg.): Symposium on Eye Tracking Research and Applications: Full Papers: ETRA 2021: Online, 25. - 27. Mai: New York: Association for Computing Machinery (ACM), S. 3:1-3:11. Online verfügbar unter https://doi.org/10.1145/3448017.3457377, zuletzt geprüft am 03.09.2021
Abstract: In this paper we showcase several eye movement data visualizations and how they can be interactively linked to design a flexible visualization tool for eye movement data. The aim of this project is to create a user-friendly and easy accessible tool to interpret visual attention patterns and to facilitate data analysis for eye movement data. Hence, to increase accessibility and usability we provide a web-based solution. Users can upload their own eye movement data set and inspect it from several perspectives simultaneously. Insights can be shared and collaboratively be discussed with others. The currently available visualization techniques are a 2D density plot, a scanpath representation, a bee swarm, and a scarf plot, all supporting several standard interaction techniques. Moreover, due to the linking feature, users can select data in one visualization, and the same data points will be highlighted in all active visualizations for solving comparison tasks. The tool also provides functions that make it possible to upload both, private or public data sets, and can generate URLs to share the data and settings of customized visualizations. A user study showed that the tool is understandable and that providing linked customizable views is beneficial for analyzing eye movement data.
-
(2020): What more than a hundred project groups reveal about teaching visualization. In: Journal of Visualization 23, S. 895-911. Online verfügbar unter https://doi.org/10.1007/s12650-020-00659-6, zuletzt geprüft am 07.05.2021
Abstract: The growing number of students can be a challenge for teaching visualization lectures, supervision, evaluation, and grading. Moreover, designing visualization courses by matching the different experiences and skills of the students is a major goal in order to find a common solvable task for all of them. Particularly, the given task is important to follow a common project goal, to collaborate in small project groups, but also to further experience, learn, or extend programming skills. In this article, we survey our experiences from teaching 116 student project groups of 6 bachelor courses on information visualization with varying topics. Moreover, two teaching strategies were tried: 2 courses were held without lectures and assignments but with weekly scrum sessions (further denoted by TS1) and 4 courses were guided by weekly lectures and assignments (further denoted by TS2). A total number of 687 students took part in all of these 6 courses. Managing the ever growing number of students in computer and data science is a big challenge in these days, i.e., the students typically apply a design-based active learning scenario while being supported by weekly lectures, assignments, or scrum sessions. As a major outcome, we identified a regular supervision either by lectures and assignments or by regular scrum sessions as important due to the fact that the students were relatively unexperienced bachelor students with a wide range of programming skills, but nearly no visualization background. In this article, we explain different subsequent stages to successfully handle the upcoming problems and describe how much supervision was involved in the development of the visualization project. The project task description is given in a way that it has a minimal number of requirements but can be extended in many directions while most of the decisions are up to the students like programming languages, visualization approaches, or interaction techniques. Finally, we discuss the benefits and drawbacks of both teaching strategies.
-
(2020): Exploring eye movement data with image-based clustering. In: Journal of Visualization 23, S. 677-694. Online verfügbar unter https://doi.org/10.1007/s12650-020-00656-9, zuletzt geprüft am 07.05.2021
Abstract: In this article, we describe a new feature for exploring eye movement data based on image-based clustering. To reach this goal, visual attention is taken into account to compute a list of thumbnail images from the presented stimulus. These thumbnails carry information about visual scanning strategies, but showing them just in a space-filling and unordered fashion does not support the detection of patterns over space, time, or study participants. In this article, we present an enhancement of the EyeCloud approach that is based on standard word cloud layouts adapted to image thumbnails by exploiting image information to cluster and group the thumbnails that are visually attended. To also indicate the temporal sequence of the thumbnails, we add color-coded links and further visual features to dig deeper in the visual attention data. The usefulness of the technique is illustrated by applying it to eye movement data from a formerly conducted eye tracking experiment investigating route finding tasks in public transport maps. Finally, we discuss limitations and scalability issues of the approach.
-
(2020) : Guiding graph exploration by combining layouts and reorderings In: Nguyen, Quang Vinh; Zhao, Ying; Burch, Michael; Westenberg, Michel (Hg.): The 13th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Eindhoven, 8. - 10. Dezember: New York: Association for Computing Machinery, S. 25:1-25:5. Online verfügbar unter https://doi.org/10.1145/3430036.3430064, zuletzt geprüft am 07.05.2021
Abstract: Visualizing graphs is a challenging task due to the various properties of the underlying relational data. For sparse and small graphs the perceptually most efficient way are node-link diagrams whereas for dense graphs with attached data, adjacency matrices might be the better choice. Since graphs can contain both properties, being globally sparse and locally dense, a combination of several visualizations is beneficial. In this paper we describe a visually and algorithmically scalable approach to provide views and perspectives about graphs as interactively linked node-link as well as adjacency matrix visualizations. The novelty of the technique is that insights like clusters or anomalies from one or several combined views can be used to influence the layout or reordering of the others. Moreover, the importance of nodes and node groups can be detected, computed, and visualized by taking into account several layout and reordering properties in combination as well as different edge properties for the same set of nodes. We illustrate the usefulness of our tool by applying it to graph datasets like co-authorships, co-citations, and a CPAN distribution.
-
(2020) : VizWick. A multiperspective view of hierarchical data In: Nguyen, Quang Vinh; Zhao, Ying; Burch, Michael; Westenberg, Michel (Hg.): The 13th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Eindhoven, 8. - 10. Dezember: New York: Association for Computing Machinery, S. 23:1-23:5. Online verfügbar unter https://doi.org/10.1145/3430036.3430044, zuletzt geprüft am 07.05.2021
Abstract: In this paper we present a web-based interactive tool for visualizing hierarchical data. Our main purpose is to facilitate the visualization of datasets. We achieve this by offering VizWick in a browser environment, with no requirement of additional software. We provide the option to view the same dataset from multiple coordinated perspectives, thus providing the possibility to gain more analytical insight than if the dataset was visualized in a single view. We focus on several hierarchy visualization techniques which can be either in 2D, 3D, or a virtual reality environment. The choice of programming language is JavaScript, with the aid of PixiJS and Three.js libraries. We demonstrate the usefulness of our tool by applying it to the NCBI taxonomy, a hierarchically structured dataset which contains over 300,000 elements.
-
(2020) : Comparing dimensionality reductions for eye movement data In: Nguyen, Quang Vinh; Zhao, Ying; Burch, Michael; Westenberg, Michel (Hg.): The 13th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Eindhoven, 8. - 10. Dezember: New York: Association for Computing Machinery, S. 18:1-18:5. Online verfügbar unter https://doi.org/10.1145/3430036.3430049, zuletzt geprüft am 07.05.2021
Abstract: Eye movement data is high-dimensional, and therefore hard to visualize. In this paper we focus on a dataset of scanpaths: Eye movements performed by subjects and tracked during a task which is based on path-finding. We describe comparisons of different approaches of dimensionality reduction applied to eye movement data, including t-distributed stochastic neighbor embedding (t-SNE), uniform manifold approximation and projection (UMAP), principal component analysis (PCA), and metric multidimensional scaling (MDS). We describe a tool created to analyze and compare these different methods, and perform a case study in which we explore an eye movement dataset.
-
(2020) : Voronoier. From images to Voronoi diagrams In: Nguyen, Quang Vinh; Zhao, Ying; Burch, Michael; Westenberg, Michel (Hg.): The 13th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Eindhoven, 8. - 10. Dezember: New York: Association for Computing Machinery, S. 16:1-16:9. Online verfügbar unter https://doi.org/10.1145/3430036.3430043, zuletzt geprüft am 07.05.2021
Abstract: We describe an interactive application for transforming an image into a Voronoi diagram. We combine a variety of methods for generating a spatial point cloud from an input image. In addition, several methods for pruning the spatial point cloud are introduced. These pruning methods can significantly reduce the computation time needed for the transformation. A Voronoi diagram can be constructed from the pruned spatial point cloud using either a naive approach or a Delaunay triangulation. Moreover, an order-k Voronoi diagram can be constructed using this naive approach. We introduce many configuration parameters and we integrate interactivity in the Voronoi diagram by giving users the ability to manually add and remove centroids. To make the application accessible to everyone, we provide a web-based solution by using the Vue.js framework based on the JavaScript programming language. This solution supports the transformation from an image to a Voronoi diagram in a browser, and hence, has the advantage of not being restricted to a certain kind of environment. We illustrate the usefulness of our application by applying it to several images.
-
(2020) : eDBLP. Visualizing scientific publications In: Nguyen, Quang Vinh; Zhao, Ying; Burch, Michael; Westenberg, Michel (Hg.): The 13th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Eindhoven, 8. - 10. Dezember: New York: Association for Computing Machinery, S. 9:1-9:8. Online verfügbar unter https://doi.org/10.1145/3430036.3430052, zuletzt geprüft am 07.05.2021
Abstract: In this paper we describe an approach for visualizing the textual information archived in the DBLP and the static and dynamic relations contained in it. Those relations are existing between authors and co-authors, between keywords, but also between authors and keywords. Visually representing them provides a way to quickly get an overview about emerging or disappearing topics as well as researchers and researcher groups. To reach our goal we apply node-link diagrams, word clouds, heatmaps, and area plots to the preprocessed and transformed DBLP data. All visualizations are equipped with interaction techniques and are built by using the functionality of the Bokeh library in Python, which enables the users to run the eDBLP in a web browser and to explore the dataset in an interactive and intuitive way. Finally, we discuss limitations and scalability issues of our approach.
-
(2020) : Multiple linked perspectives on hierarchical data In: Nguyen, Quang Vinh; Zhao, Ying; Burch, Michael; Westenberg, Michel (Hg.): The 13th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Eindhoven, 8. - 10. Dezember: New York: Association for Computing Machinery, S. 3:1-3:8. Online verfügbar unter https://doi.org/10.1145/3430036.3430037, zuletzt geprüft am 07.05.2021
Abstract: This paper describes an interactive web-based tool for visualizing hierarchical data including the recently developed concept of space-reclaiming icicle plots and several more traditional hierarchy visualizations. The tool provides ways to upload, share, explore, and compare hierarchical data using a multitude of different linked hierarchy visualizations. The current version supports up to 8 hierarchy visualizations, with the space-reclaiming icicle plots among them. Several of the visualizations can be shown in linked views while typical hierarchy parameters and visual variables can be changed on user demand. The interactive tool makes use of OpenGL and Angular, an industry standard JavaScript platform, and runs in a web browser. We illustrate the usefulness of the visualization tool by applying it to the NCBI taxonomy that consists of more than 300,000 hierarchically organized species while filtering for the tetrapoda subhierarchy. Finally, we explain implementation details and discuss limitations and scalability issues of the linked visualization techniques.
-
(2020) : Visual Analysis of Eye Movements During Game Play In: Bulling, Andreas; Huckauf, Anke; Eakta, Jain; Radach, Ralph; Weiskopf, Daniel (Hg.): Symposium on Eye Tracking Research and Applications: Short Papers: ETRA 2020: Online, 2. - 5. Juni: New York: Association for Computing Machinery (ACM), S. 59:1-59:5. Online verfügbar unter https://doi.org/10.1145/3379156.3391839, zuletzt geprüft am 07.05.2021
Abstract: Eye movements indicate visual attention and strategies during game play, regardless of whether in board, sports, or computer games. Additional factors such as individual vs. group play and active playing vs. observing game play further differentiate application scenarios for eye movement analysis. Visual analysis has proven to be an effective means to investigate and interpret such highly dynamic spatio-temporal data. In this paper, we contribute a classification strategy for different scenarios for the visual analysis of gaze data during game play. Based on an initial sample of related work, we derive multiple aspects comprising data sources, game mode, player number, player state, analysis mode, and analysis goal. We apply this classification strategy to describe typical analysis scenarios and research questions as they can be found in related work. We further discuss open challenges and research directions for new application scenarios of eye movements in game play.
-
(2020) : Sankeye. A Visualization Technique for AOI Transitions In: Bulling, Andreas; Huckauf, Anke; Eakta, Jain; Radach, Ralph; Weiskopf, Daniel (Hg.): Symposium on Eye Tracking Research and Applications: Short Papers: ETRA 2020: Online, 2. - 5. Juni: New York: Association for Computing Machinery (ACM), S. 48:1-48:5. Online verfügbar unter https://doi.org/10.1145/3379156.3391833, zuletzt geprüft am 07.05.2021
Abstract: Visually exploring AOI transitions aggregated from a group of eye tracked people is a challenging task. Many visualizations typically produce visual clutter or aggregate the temporal or visit order information in the data hiding the visual task solution strategies for the observer. In this paper we introduce the Sankeye technique that is based on the visual metaphor of Sankey diagrams applied to eye movement data, hence the name Sankeye. The technique encodes the frequencies of AOI transitions into differently thick rivers and subrivers. The distributions of the AOI transitions are visually represented by splitting and merging subrivers in a left-to-right reading direction. The technique allows to interactively adapt the number of predefined AOIs as well as the transition frequency number threshold with the goal to derive patterns and insights from eye movement data.
-
(2020) : Teaching Eye Tracking Visual Analytics in Computer and Data Science Bachelor Courses In: Bulling, Andreas; Huckauf, Anke; Eakta, Jain; Radach, Ralph; Weiskopf, Daniel (Hg.): Symposium on Eye Tracking Research and Applications: Full Papers: ETRA 2020: Online, 2. - 5. Juni: New York: Association for Computing Machinery (ACM), S. 17:1-17:9. Online verfügbar unter https://doi.org/10.1145/3379155.3391331, zuletzt geprüft am 03.09.2021
Abstract: Making students aware of eye tracking technologies can have a great benefit on the entire application field since they may build the next generation of eye tracking researchers. On the one hand students learn the usefulness and benefits of this technique for different scientific purposes like user evaluation to find design flaws or visual attention strategies, gaze-assisted interaction to enhance and augment traditional interaction techniques, or as a means to improve virtual reality experiences. However, on the other hand, the large amount of recorded data means a challenge for data analytics in order to find rules, patterns, but also anomalies in the data, finally leading to insights and knowledge to understand or predict eye movement patterns which can have synergy effects for both disciplines - eye tracking and visual analytics. In this paper we will describe the challenges of teaching eye tracking combined with visual analytics in a computer and data science bachelor course with 42 students in an active learning scenario following four teaching stages. Some of the student project results are shown to demonstrate learning outcomes with respect to eye tracking data analysis and visual analytics techniques.
-
(2020) : The Importance of Requirements Engineering for Teaching Large Visualization Courses: Fourth International Workshop on Learning from Other Disciplines for Requirements Engineering: Proceedings: D4RE: Zürich, 31. August. IEEE Computer Society: Los Alamitos, Washington, Tokyo: Conference Publishing Services, S. 6-10. Online verfügbar unter https://doi.org/10.1109/D4RE51199.2020.00007, zuletzt geprüft am 07.05.2021
Abstract: Teaching visualization courses typically requires some kind of small-scale software project in which the students collaboratively create a software product with the goal to practically apply visualization concepts. This software focuses on providing an interactive solution to a given dataset scenario supporting the detection of insights based on users' tasks at hand. However, while creating such a tool several software development stages have to be taken into account, with requirements engineering as one of the major repeating stages. In this paper we describe three different visualization project-based teaching strategies TS_H, TS_M, and TS_L depending on the degree of freedom for the student groups. Moreover, they differ in the way how requirements engineering is an inherent ingredient in order to design, implement, test, deploy, evaluate, maintain, and evolve a certain software product. We experienced with more than 1,000 students in a total of 9 courses running over 8 weeks each, in approximately 2 years of time. All of the three teaching strategies have their own benefits and drawbacks, however, requirements engineering is considered more or less important, mostly depending on the degree of freedom the student project groups got during the courses. As a major outcome we consider the courses successful, not only because we learned the importance of requirements engineering for teaching project-based visualization courses, but also because many students passed the courses, the student evaluation was quite positive, and the written reports showed that they had an immense learning effect.
-
(2020) : PasVis. Enhancing public transport maps with interactive passenger data visualizations In: Nguyen, Quang Vinh; Zhao, Ying; Burch, Michael; Westenberg, Michel (Hg.): The 13th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Eindhoven, 8. - 10. Dezember: New York: Association for Computing Machinery, S. 13:1-13.8. Online verfügbar unter https://doi.org/10.1145/3430036.3430061, zuletzt geprüft am 07.05.2021
Abstract: Public transport maps are typically designed in a way to support route finding tasks for passengers while they also provide an overview about stations, metro lines, and city-specific attractions. Most of those maps are designed as a static representation, maybe placed in a metro station or printed in a travel guide. In this paper we describe a dynamic, interactive public transport map visualization enhanced by additional views for the dynamic passenger data on different levels of temporal granularity. Moreover, we also allow extra statistical information in form of density plots, calendar-based visualizations, and line graphs. All this information is linked to the contextual metro map to give a viewer insights into the relations between time points and typical routes taken by the passengers. We illustrate the usefulness of our interactive visualization by applying it to the railway system of Hamburg in Germany while also taking into account the extra passenger data. As another indication for the usefulness of the interactively enhanced metro maps we conducted a user experiment with 20 participants.
-
(2020): Graph-Related Properties for Comparing Dynamic Call Graphs. In: Journal of Computer Languages. Online verfügbar unter https://doi.org/10.1016/j.cola.2020.100967, zuletzt geprüft am 03.09.2021
Abstract: Software systems produce long sequences of call graphs, in particular, if the graphs are generated during runtime and not revision by revision. Visualizing, analyzing, and interacting with such long dynamic graphs with respect to different properties is a challenging task. In this article we describe an interactive visualization technique for dynamic call graphs that supports the observation of the data in vertex, edge, and time dimensions based on properties related to the graph topology, inherent vertex hierarchy, involved links, and graph-theoretic problems. Moreover, we provide a time-aligned view on several dynamic graphs with the goal to compare them visually. We also provide standard node-link diagrams for individual graphs or aggregated dynamic graph subsequences as a details-on-demand technique and for supporting graph comparisons on different temporal granularities. We illustrate the usefulness of the dynamic graph visualization by applying it to the call relations at runtime of the open source software project JHotDraw. We evaluated the interactive visualization by reflecting on the static and dynamic patterns we could identify in the dataset by changing the graph properties under exploration. Moreover, we conducted a controlled user study with 20 participants investigating three typical tasks like finding graph sequences, identifying a complete graph, and exploring the reason for a change in a shortest path algorithm. Finally, we discuss scalabilities and limitations of our approach.
-
(2020) : Procedural City Modeling for AR Applications: Information Visualisation: AI & Analytics, Biomedical Visualization, Builtviz, and Geometric Modelling & Imaging: Proceedings: 24th International Conference on Information Visualisation (IV): Melbourne, 7. - 11. September: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 581-586. Online verfügbar unter https://doi.org/10.1109/IV51561.2020.00098, zuletzt geprüft am 03.09.2021
Abstract: In this paper we present a procedural city modeling approach which combines real-world street data and the multi-nuclei theory to generate believable cities. Our approach performs a partitioning of a city into urban zones based on Perlin noise and different parameters that are adjustable by the user. Our method is efficient enough to be used for augmented reality applications to be run on devices with limited processing capabilities such as smartphones. The approach can be used to build applications for professional urban planners and entertainment purposes. We illustrate the usefulness of our approach by applying it to data of three cities. Moreover, we provide implementation details and discuss challenges and limitations of the technique in the light of several application scenarios.
-
(2020) : Visual Analysis of FIFA World Cup Data: Information Visualisation: AI & Analytics, Biomedical Visualization, Builtviz, and Geometric Modelling & Imaging: Proceedings: 24th International Conference on Information Visualisation (IV): Melbourne, 7. - 11. September: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 114-119. Online verfügbar unter https://doi.org/10.1109/IV51561.2020.00028, zuletzt geprüft am 09.09.2021
Abstract: Soccer is one of the most popular sports in the world, played by thousands of professionals and amateurs every week. Consequently, it is no surprise that it generates an enormous amount of data. In today's data-driven world it is essential to find an optimal, self-explanatory, way to present the data in a way to be able to derive visual patterns that relate to the underlying data patterns. In this paper, we describe an interactive visualization for analyzing soccer data and identifying patterns, correlations, and insights. We illustrate the usefulness of our approach, especially targeted towards non-visualization experts, by applying it to World Cup data and by discussing potential use cases.
-
(2020) : Visualizing dynamic graphs with heat triangles In: Nguyen, Quang Vinh; Zhao, Ying; Burch, Michael; Westenberg, Michel (Hg.): The 13th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Eindhoven, 8. - 10. Dezember: New York: Association for Computing Machinery, S. 7:1-7:8. Online verfügbar unter https://doi.org/10.1145/3430036.3430053, zuletzt geprüft am 07.05.2021
Abstract: In this paper an overview-based interactive visualization for temporally long dynamic graph sequences is described. To reach this goal, each graph can be mapped to a certain value based on a given property. Among others, a property can be number of vertices, number of edges, average degree, density, number of self-loops, degree (maximum and total), or edge weight (minimum, maximum, and total). To achieve an overview over time, an aggregation strategy based on either the mean, minimum, or maximum of two values is applied. This temporal value aggregation generates a triangular shape with an overview of the entire graph sequence as the peak. The color coding can be adjusted, forming visual patterns that can be rapidly explored for certain data features over time, supporting comparison tasks between the properties. The usefulness of the approach is illustrated by means of applying it to dynamic graphs generated from US domestic flight data.
-
(2020): What We See and What We Get from Visualization. Eye Tracking Beyond Gaze Distributions and Scanpaths. Position Paper. Online verfügbar unter https://arxiv.org/abs/2009.14515, zuletzt geprüft am 07.05.2021
Abstract: Technical progress in hardware and software enables us to record gaze data in everyday situations and over long time spans. Among a multitude of research opportunities, this technology enables visualization researchers to catch a glimpse behind performance measures and into the perceptual and cognitive processes of people using visualization techniques. The majority of eye tracking studies performed for visualization research is limited to the analysis of gaze distributions and aggregated statistics, thus only covering a small portion of insights that can be derived from gaze data. We argue that incorporating theories and methodology from psychology and cognitive science will benefit the design and evaluation of eye tracking experiments for visualization. This position paper outlines our experiences with eye tracking in visualization and states the benefits that an interdisciplinary research field on visualization psychology might bring for better understanding how people interpret visualizations.
-
(2020) : Space-Reclaiming Icicle Plots In: Beck, Fabian; Seo, Jinwook; Wang, Chaoli (Hg.): IEEE Pacific Visualization Symposium: Proceedings: PacificVis: Online, 3. - 5. Juni: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 121-130. Online verfügbar unter https://doi.org/10.1109/PacificVis48177.2020.4908, zuletzt geprüft am 03.09.2021
Abstract: This paper describes the space-reclaiming icicle plots, hierarchy visualizations based on the visual metaphor of icicles. As a novelty, our approach tries to reclaim empty space in all hierarchy levels. This reclaiming results in an improved visibility of the hierarchy elements especially those in deeper levels. We implemented an algorithm that is capable of producing more space-reclaiming icicle plot variants. Several visual parameters can be tweaked to change the visual appearance and readability of the plots: among others, a space-reclaiming parameter, an empty space shrinking parameter, and a gap size. To illustrate the usefulness of the novel visualization technique we applied it, among others, to an NCBI taxonomy dataset consisting of more than 300,000 elements and with maximum depth 42. Moreover, we explore the parameter and design space by applying several values for the visual parameters. We also conducted a controlled user study with 17 participants and received qualitative feedback from 112 students from a visualization course.
-
(2020) : Attention-based Cross-Modal Unification of Visualized Text and Image Features. Understanding the influence of interface and user idiosyncrasies on unification for free-viewing In: Bulling, Andreas; Huckauf, Anke; Eakta, Jain; Radach, Ralph; Weiskopf, Daniel (Hg.): Symposium on Eye Tracking Research and Applications: Adjunct Proceedings: ETRA 2020: Online, 2. - 5. Juni: New York: Association for Computing Machinery (ACM), S. 29:1-29:9. Online verfügbar unter https://doi.org/10.1145/3379157.3391303, zuletzt geprüft am 03.09.2021
Abstract: The attentional analysis on graphical user interfaces (GUIs) is shifting from Areas-of-Interest (AOIs) to Data-of-Interest (DOI). However, the heterogeneity data modalities on GUIs hinder the DOI-based analyses. To overcome this limitation, we present a Canonical Correlation Analysis (CCA) based approach to unify the heterogeneous modalities (text and images) concerning user attention. Especially, the influence of interface and user idiosyncrasies in establishing the cross-modal correlation is studied. The performance of the proposed approach is analyzed for free-viewing eye-tracking experiments conducted on bi-modal webpages. The results reveal: (i) Cross-modal text and image visual features are correlated when the interface idiosyncrasies, alone or along with user idiosyncrasies, are constrained. (ii) The font-families of text are comparable to color histogram visual features of images in drawing the users’ attention. (iii) Text and image visual features can delineate the attention of each other. Our approach finds applications in user-oriented webpage rendering and computational attention modeling.
-
(2019): Volume-based large dynamic graph analysis supported by evolution provenance. In: Multimedia Tools and Applications 78, S. 32939-32965. Online verfügbar unter https://doi.org/10.1007/s11042-019-07878-6, zuletzt geprüft am 09.09.2021
Abstract: We present an approach for the visualization and interactive analysis of dynamic graphs that contain a large number of time steps. A specific focus is put on the support of analyzing temporal aspects in the data. Central to our approach is a static, volumetric representation of the dynamic graph based on the concept of space-time cubes that we create by stacking the adjacency matrices of all time steps. The use of GPU-accelerated volume rendering techniques allows us to render this representation interactively. We identified four classes of analytics methods as being important for the analysis of large and complex graph data, which we discuss in detail: data views, aggregation and filtering, comparison, and evolution provenance. Implementations of the respective methods are presented in an integrated application, enabling interactive exploration and analysis of large graphs. We demonstrate the applicability, usefulness, and scalability of our approach by presenting two examples for analyzing dynamic graphs. Furthermore, we let visualization experts evaluate our analytics approach.
-
(2019) : Teaching and Evaluating Collaborative Group Work in Large Visualization Courses In: Wang, Changbo; Burch, Michael; Krone, Michael (Hg.): The 12th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Shanghai, 20. - 22. September: New York: Association for Computing Machinery (ACM), S. 17:1-17:8. Online verfügbar unter https://doi.org/10.1145/3356422.3356447, zuletzt geprüft am 09.09.2021
Abstract: The growing number of students can be a challenge for teaching visualization lectures, supervision, evaluation, and grading. Moreover, designing a visualization course, matching the different experiences and skills of the students is one major goal in order to find a common solvable task for all of the students. However, the given task is important to follow a common goal, to collaborate in small project groups, but also to further experience, learn, or extend programming skills. In this paper we describe an approach to manage a large number of 272 students in a design-based active learning course who were relatively unexperienced first year bachelor students with a wide range of programming skills. We explain different subsequent stages to successfully handle the upcoming problems and describe how many and to which extent supervisors are involved in the development of the project. The project task description is given in a way that it has a minimal number of requirements but can be extended in many directions while most of the decisions are up to the students like programming languages, visualization approaches, or interaction techniques. Finally, we discuss the benefits and drawbacks of our teaching strategy.
-
(2019) : EyeClouds. A Visualization and Analysis Tool for Exploring Eye Movement Data In: Wang, Changbo; Burch, Michael; Krone, Michael (Hg.): The 12th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Shanghai, 20. - 22. September: New York: Association for Computing Machinery (ACM), S. 8:1-8:8. Online verfügbar unter https://doi.org/10.1145/3356422.3356423, zuletzt geprüft am 09.09.2021
Abstract: In this paper, we discuss and evaluate the advantages and disadvantages of several techniques to visualize and analyze eye movement data tracked and recorded from public transport map viewers in a formerly conducted eye tracking experiment. Such techniques include heat maps and gaze stripes. To overcome the disadvantages and improve the effectiveness of those techniques, we present a viable solution that makes use of existing techniques such as heat maps and gaze stripes, as well as attention clouds which are inspired by the general concept of word clouds. We also develop a web application with interactive attention clouds, named the EyeCloud, to put theory into practice. The main objective of this paper is to help public transport map designers and producers gain feedback and insights on how the current design of the map can be further improved, by leveraging on the visualization tool. In addition, this visualization tool, the EyeCloud, can be easily extended to many other purposes with various types of data. It could be possibly applied to entertainment industries, for instance, to track the attention of the film audiences in order to improve the advertisements.
-
(2019) : Combining Interactive Hierarchy Visualizations in a Web-based Application In: Kerren, Andreas; Hurter, Christophe; Braz, Jose (Hg.): 14th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications: Proceedings. Volume 3: VISIGRAPP 2019 (IVAPP): Prag, 25. - 27. Februar: Setúbal: SciTePress, S. 191-198. Online verfügbar unter https://doi.org/10.5220/0007307701910198, zuletzt geprüft am 09.09.2021
Abstract: In this paper we describe a web-based tool combining several hierarchy visualization techniques. Those run in a browser and support the communication of hierarchy data that is omnipresent in many application fields like biology, software engineering, sports, or in algorithmic approaches like hierarchical clustering. To this end we provide node-link diagrams, Pythagoras trees, circular, as well as 3D treemaps also called 3D step-trees to give several visual perspectives on the same data and to improve data exploration tasks. The visualizations are interactive and linked, while the tool is available online, making it easily accessible for people all around the world without installing extra software or relying on additional libraries and frameworks. Hierarchy datasets can be uploaded to a server and shared with others. The visualizations were primarily implemented using JavaScript, and more specifically, rendered using the D3.js library. We illustrate the usefulness of the interactive visualization by applying them to the NCBI taxonomy and the Influenza dataset.
-
(2019) : An interactive web-based visual analytics tool for detecting strategic eye movement patterns: Symposium on Eye Tracking Research and Applications: Proceedings: ETRA 2019: Denver, 25. - 28. Juni: New York: Association for Computing Machinery (ACM), S. 93:1-93:5. Online verfügbar unter https://doi.org/10.1145/3317960.3321615, zuletzt geprüft am 09.09.2021
Abstract: In this paper we describe an interactive and web-based visual analytics tool combining linked visualization techniques and algorithmic approaches for exploring the hierarchical visual scanning behavior of a group of people when solving tasks in a static stimulus. This has the benefit that the recorded eye movement data can be observed in a more structured way with the goal to find patterns in the common scanning behavior of a group of eye tracked people. To reach this goal we first preprocess and aggregate the scanpaths based on formerly defined areas of interest (AOIs) which generates a weighted directed graph. We visually represent the resulting AOI graph as a modified hierarchical graph layout. This can be used to filter and navigate in the eye movement data shown in a separate view overplotted on the stimulus for preserving the mental map and for providing an intuitive view on the semantics of the original stimulus. Several interaction techniques and complementary views with visualizations are implemented. Moreover, due to the web-based nature of the tool, users can upload, share, and explore data with others. To illustrate the usefulness of our concept we apply it to real-world eye movement data from a formerly conducted eye tracking experiment.
-
(2019) : Interaction graphs. Visual analysis of eye movement data from interactive stimuli: Symposium on Eye Tracking Research and Applications: Proceedings: ETRA 2019: Denver, 25. - 28. Juni: New York: Association for Computing Machinery (ACM), S. 89:1-89:5. Online verfügbar unter ttps://doi.org/10.1145/3317960.3321617, zuletzt geprüft am 09.09.2021
Abstract: Eye tracking studies have been conducted to understand the visual attention in different scenarios like, for example, how people read text, which graphical elements in a visualization are frequently attended, how they drive a car, or how they behave during a shopping task. All of these scenarios - either static or dynamic - show a visual stimulus in which the spectators are not able to change the visual content they see. This is different if interaction is allowed like in (graphical) user interfaces (UIs), integrated development environments (IDEs), dynamic web pages (with different user-defined states), or interactive displays in general as in human-computer interaction, which gives a viewer the opportunity to actively change the stimulus content. Typically, for the analysis and visualization of time-varying visual attention paid to a web page, there is a big difference for the analytics and visualization approaches - algorithmically as well as visually - if the presented web page stimulus is static or dynamic, i.e. time-varying, or dynamic in the sense that user interaction is allowed. In this paper we discuss the challenges for visual analysis concepts in order to analyze the recorded data, in particular, with the goal to improve interactive stimuli, i.e., the layout of a web page, but also the interaction concept. We describe a data model which leads to interaction graphs, a possible way to analyze and visualize this kind of eye movement data.
-
(2019) : Finding the outliers in scanpath data: Symposium on Eye Tracking Research and Applications: Proceedings: ETRA 2019: Denver, 25. - 28. Juni: New York: Association for Computing Machinery (ACM), S. 83:1-83:5. Online verfügbar unter https://doi.org/10.1145/3317958.3318225, zuletzt geprüft am 09.09.2021
Abstract: In this paper, we describe the design of an interactive visualization tool for the comparison of eye movement data with a special focus on the outliers. In order to make the tool usable and accessible to anyone with a data science background, we provide a web-based solution by using the Dash library based on the Python programming language and the Python library Plotly. Interactive visualization is very well supported by Dash, which makes the visualization tool easy to use. We support multiple ways of comparing user scanpaths like bounding boxes and Jaccard indices to identify similarities. Moreover, we support matrix reordering to clearly separate the outliers in the scanpaths. We further support the data analyst by complementary views such as gaze plots and visual attention maps.
-
(2019) : Clustered eye movement similarity matrices: Symposium on Eye Tracking Research and Applications: Proceedings: ETRA 2019: Denver, 25. - 28. Juni: New York: Association for Computing Machinery (ACM), S. 82:1-82:9. Online verfügbar unter ttps://doi.org/10.1145/3317958.3319811, zuletzt geprüft am 09.09.2021
Abstract: Eye movements recorded for many study participants are difficult to interpret, in particular when the task is to identify similar scanning strategies over space, time, and participants. In this paper we describe an approach in which we first compare scanpaths, not only based on Jaccard (JD) and bounding box (BB) similarities, but also on more complex approaches like longest common subsequence (LCS), Frechet distance (FD), dynamic time warping (DTW), and edit distance (ED). The results of these algorithms generate a weighted comparison matrix while each entry encodes the pairwise participant scanpath comparison strength. To better identify participant groups of similar eye movement behavior we reorder this matrix by hierarchical clustering, optimal-leaf ordering, dimensionality reduction, or a spectral approach. The matrix visualization is linked to the original stimulus overplotted with visual attention maps and gaze plots on which typical interactions like temporal, spatial, or participant-based filtering can be applied.
-
(2019) : Visually comparing eye movements over space and time: Symposium on Eye Tracking Research and Applications: Proceedings: ETRA 2019: Denver, 25. - 28. Juni: New York: Association for Computing Machinery (ACM), S. 81:1-81:9. Online verfügbar unter https://doi.org/10.1145/3317958.3319810, zuletzt geprüft am 09.09.2021
Abstract: Analyzing and visualizing eye movement data can provide useful insights into the connectivities and linkings of points and areas of interest (POIs and AOIs). Those typically time-varying relations can give hints about applied visual scanning strategies by either individual or many eye tracked people. However, the challenging issue with this kind of data is its spatio-temporal nature requiring a good visual encoding in order to first, achieve a scalable overview-based diagram, and second, to derive static or dynamic patterns that might correspond to certain comparable visual scanning strategies. To reliably identify the dynamic strategies we describe a visualization technique that generates a more linear representation of the spatio-temporal scan paths. This is achieved by applying different visual encodings of the spatial dimensions that typically build a limitation for an eye movement data visualization causing visual clutter effects, overdraw, and occlusions while the temporal dimension is depicted as a linear time axis. The presented interactive visualization concept is composed of three linked views depicting spatial, metrics-related, as well as distance-based aspects over time.
-
(2019) : Task classification model for visual fixation, exploration, and search: Symposium on Eye Tracking Research and Applications: Proceedings: ETRA 2019: Denver, 25. - 28. Juni: New York: Association for Computing Machinery (ACM), S. 65:1-65:4. Online verfügbar unter https://doi.org/10.1145/3314111.3323073, zuletzt geprüft am 09.09.2021
Abstract: Yarbus' claim to decode the observer's task from eye movements has received mixed reactions. In this paper, we have supported the hypothesis that it is possible to decode the task. We conducted an exploratory analysis on the dataset by projecting features and data points into a scatter plot to visualize the nuance properties for each task. Following this analysis, we eliminated highly correlated features before training an SVM and Ada Boosting classifier to predict the tasks from this filtered eye movements data. We achieve an accuracy of 95.4% on this task classification problem and hence, support the hypothesis that task classification is possible from a user's eye movement data.
-
(2019) : Visual Analysis of Formula One Races: Information Visualisation: Biomedical Visualization and Geometric Modelling & Imaging: Proceedings: 23rd International Conference on Information Visualisation (IV. Part I): Paris, 2. - 5. Juli: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 94-99. Online verfügbar unter https://doi.org/10.1109/IV.2019.00025, zuletzt geprüft am 09.09.2021
Abstract: In this paper we describe an interactive web-based visual analysis tool for Formula one races. It first provides an overview about all races on a yearly basis in a calendar-like representation. From this starting point, races can be selected and visually inspected in detail. We support a dynamic race position diagram as well as a more detailed lap times line plot for showing the drivers' lap times in comparison. Many interaction techniques are supported like selections, filtering, highlighting, color coding, or details-on-demand. We illustrate the usefulness of our visualization tool by applying it to a Formula one dataset while we describe the different dynamic visual racing patterns for a number of selected races and drivers.
-
(2019) : Overlap-Free Drawing of Generalized Pythagoras Trees for Hierarchy Visualization: International Conference on Visualisation: Proceedings: IEEE Visualization Conference (VIS): Vancouver, 20. - 25. Oktober: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 251-255. Online verfügbar unter https://doi.org/10.1109/VISUAL.2019.8933606, zuletzt geprüft am 09.09.2021
Abstract: Generalized Pythagoras trees were developed for visualizing hierarchical data, producing organic, fractal-like representations. However, the drawback of the original layout algorithm is visual overlap of tree branches. To avoid such overlap, we introduce an adapted drawing algorithm using ellipses instead of circles to recursively place tree nodes representing the subhierarchies. Our technique is demonstrated by resolving overlap in diverse real-world and generated datasets, while comparing the results to the original approach.
-
(2018) : Clustering for stacked edge splatting: Vision, Modeling, and Visualization: Proceedings: VMV 2018: Stuttgart, 10. - 12. Oktober: Goslar: Eurographics Association, S. 127-134. Online verfügbar unter https://doi.org/10.2312/vmv.20181262, zuletzt geprüft am 09.09.2021
Abstract: We present a time-scalable approach for visualizing dynamic graphs. By adopting bipartite graph layouts known from parallel edge splatting, individual graphs are horizontally stacked by drawing partial edges, leading to stacked edge splatting. This allows us to uncover the temporal patterns together with achieving time-scalability. To preserve the graph structural information, we introduce the representative graph where edges are aggregated and drawn at full length. The representative graph is then placed on the top of the last graph in the (sub)sequence. This allows us to obtain detailed information about the partial edges by tracing them back to the representative graph. We apply sequential temporal clustering to obtain an overview of different temporal phases of the graph sequence together with the corresponding structure for each phase. We demonstrate the effectiveness of our approach by using real-world datasets.
-
(2018) : Volume-Based Large Dynamic Graph Analytics: Information Visualisation: Biomedical Visualization, Visualisation on Built and Rural Environments & Geometric Modelling and Imaging: Proceedings: 22nd International Conference on Information Visualisation (IV): Fisciano, 10. - 13. Juli: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 210-219. Online verfügbar unter https://doi.org/10.1109/iV.2018.00045, zuletzt geprüft am 09.09.2021
Abstract: We present an approach for interactively analyzing large dynamic graphs consisting of several thousand time steps with a particular focus on temporal aspects. we employ a static representation of the time-varying graph based on the concept of space-time cubes, i.e., we create a volumetric representation of the graph by stacking the adjacency matrices of each of its time steps. To achieve an efficient analysis of complex data, we discuss three classes of analytics methods of particular importance in this context: data views, aggregation and filtering, and comparison. For these classes, we present a GPU-based implementation of respective analysis methods that enable the interactive analysis of large graphs. We demonstrate the utility as well as the scalability of our approach by presenting application examples for analyzing different time-varying data sets.
-
(2018): Exploring density regions for analyzing dynamic graph data. In: Journal of Visual Languages & Computing, S. 133-144. Online verfügbar unter https://doi.org/10.1016/j.jvlc.2017.09.007, zuletzt geprüft am 09.09.2021
Abstract: Static or dynamic graphs are typically visualized by either node-link diagrams, adjacency matrices, adjacency lists, or hybrids thereof. In particular, for the case of a changing graph structure a viewer wishes to be able to visually compare the graphs in a sequence. Doing such a comparison task rapidly and reliably demands for visually analyzing the dynamic graph for certain dynamic patterns. In this paper we describe a novel dynamic graph visualization that is based on the concept of smooth density fields generated by first splatting the link information of a given graph in a certain layout or visual metaphor. To further visually enhance the time-varying graph structures we add user-adaptable isolines to the resulting dynamic graph representation. The computed visual encoding of the dynamic graph is aesthetically appealing due to its smooth curves and can additionally be used to do comparisons in a long graph sequence, i.e., from an information visualization perspective it serves as an overview representation supporting to start more detailed analysis processes. To demonstrate the usefulness of the technique we explore real-world dynamic graph data by taking into account visual parameters like visual metaphors, node-link layouts, smoothing iterations, number of isolines, and different color codings. In this extended work we additionally incorporate matrix and list splatting while also supporting the selection of density regions with overlaid link information. Moreover, from the selected graph the user can automatically apply region comparisons with other graphs based on global and local density properties. Such a feature is in particular useful for finding commonalities, hence serving as a special filtering function.
-
(2018): Eye Tracking and Visualization. Introduction to the Special Thematic Issue of the Journal of Eye Movement Research. In: Journal of Eye Movement Research 10. Online verfügbar unter https://doi.org/10.16910/jemr.10.5.1, zuletzt geprüft am 09.09.2021
Abstract: There is a growing interest in eye tracking technologies applied to support traditional visualization techniques like diagrams, charts, maps, or plots, either static, animated, or interactive ones. More complex data analyses are required to derive knowledge and meaning from the data. Eye tracking systems serve that purpose in combination with biological and computer vision, cognition, perception, visualization, human-computer-interaction, as well as usability and user experience research. The 10 articles collected in this thematic special issue provide interesting examples how sophisticated methods of data analysis and representation enable researchers to discover and describe fundamental spatio-temporal regularities in the data. The human visual system, supported by appropriate visualization tools, enables the human operator to solve complex tasks, like understanding and interpreting three-dimensional medical images, controlling air traffic by radar displays, supporting instrument flight tasks, or interacting with virtual realities. The development and application of new visualization techniques is of major importance for future technological progress.
-
(2018) : Which Symbols, Features, and Regions Are Visually Attended in Metro Maps? In: Czarnowski, Ireneusz; Howlett, Robert J.; Jain, Lakhmi C. (Hg.): Intelligent Decision Technologies 2017: Proceedings. Part II: 9th KES International Conference on Intelligent Decision Technologies (KES-IDT 2017): Vilamoura, 21. - 23. Juni 2017: Cham: Springer International Publishing (Smart Innovation, Systems and Technologies), S. 237-246. Online verfügbar unter https://doi.org/10.1007/978-3-319-59424-8_22, zuletzt geprüft am 09.09.2021
Abstract: We conducted an eye tracking study with 40 participants to understand which visual objects like metro lines, stations, interchange points, specific symbols, or extra information like labels or legends are visually attended during a free examination question scenario. In this study we did not ask a specific question like a route finding task as in a previous eye tracking study, but we let the study participants freely inspect a displayed metro map system for 20 s each. We used 24 different metro maps with the same characteristics, but varied between color coded maps and gray scale ones. Understanding the visual scanning behavior of people while inspecting metro maps is an important, but also challenging task. But positively, the analysis of such eye movement data can support a map designer to produce better maps, in particular, to find out which regions are visually attended first or most frequently, maybe to guide the viewer. The visually attended regions and objects can be a key aspect in a metro map to make them easier and faster comprehensible and finally, useful for travellers in foreign and unknown cities all over the world. The major result from our eye tracking experiment is that the study participants significantly inspect symbols that pop out from the map like the airport signs or the map legends which belong to the key features in maps. Moreover, dense regions are more frequently attended than sparse ones. The visual attention maps of colored and gray scale maps look very similar.
-
(2018) : Visual Analysis of Eye Movement Data with Fixation Distance Plots In: Czarnowski, Ireneusz; Howlett, Robert J.; Jain, Lakhmi C. (Hg.): Intelligent Decision Technologies 2017: Proceedings. Part II: 9th KES International Conference on Intelligent Decision Technologies (KES-IDT 2017): Vilamoura, 21. - 23. Juni 2017: Cham: Springer International Publishing (Smart Innovation, Systems and Technologies), S. 227-236. Online verfügbar unter https://doi.org/10.1007/978-3-319-59424-8_21, zuletzt geprüft am 09.09.2021
Abstract: Eye tracking has become an increasingly important technology in many fields of research like marketing, psychology, human-computer interaction, and also in visualization. Understanding the eye movements of people while solving a given task can be of great support to improve a visual stimulus. The challenging problem with this kind of spatio-temporal data is the difficulty to provide a useful visualization that can provide an overview about the fixations with their durations and sequential order, the saccades with their orientations and lengths, but also the distances of several fixations in space. Traditional visualizations like gaze plots - showing the stimulus in its original form overplotted with the scan paths - typically produce vast amounts of visual clutter and make a visual exploration of the eye movement data a difficult task. In this paper we introduce the fixation distance plots that place the fixation sequences to a horizontal line of color coded and differently thick circles while showing additional saccadic information. Moreover, the user can apply distance thresholds that indicate if fixations are within a certain distance allowing to get an impression about the spatial stimulus information. We illustrate the usefulness of the approach by applying it to eye movement data from a formerly conducted eye tracking experiment investigating route finding tasks in public transport maps.
-
(2018) : The hierarchical flow of eye movements In: Chuang, Lewis L.; Burch, Michael; Kurzhals, Kuno (Hg.): 3rd Workshop on Eye Tracking and Visualization: Proceedings: ETVIS '18: Warschau, 15. Juni: New York: Association for Computing Machinery (ACM), S. 3:1-3:5. Online verfügbar unter https://doi.org/10.1145/3205929.3205930, zuletzt geprüft am 09.09.2021
Abstract: Eye movements are composed of spatial and temporal aspects. Moreover, not only the eye movements of one subject are of interest, but a data analyst is more or less interested in the scanning strategies of a group of people in a condensed form. This data aggregation can provide useful insights into the visual attention over space and time leading to the detection of possible visual problems or design flaws in the presented stimulus. In this paper we present a way to visually explore the flow of eye movements, i.e., we try to bring a layered hierarchical structure into the spatio-temporal eye movements. To reach this goal, the stimulus is spatially divided into areas of interest (AOIs) and temporally or sequentially aggregated into time periods or subsequences. The weighted AOI transitions are used to model directed graph edges while the AOIs build the graph vertices. The flow of eye movements is naturally obtained by computing hierarchical layers for the AOIs while the downward edges indicate the hierarchical flow between the AOIs on the corresponding layers.
-
(2018) : Identifying similar eye movement patterns with t-SNE: Vision, Modeling, and Visualization: Proceedings: VMV 2018: Stuttgart, 10. - 12. Oktober: Goslar: Eurographics Association, S. 111-118. Online verfügbar unter https://doi.org/10.2312/vmv.20181260, zuletzt geprüft am 09.09.2021
Abstract: In this paper we describe an approach based on the t-distributed stochastic neighbor embedding (t-SNE) focusing on projecting high-dimensional eye movement data to two dimensions. The lower-dimensional data is then represented as scatterplots reflecting the local structure of the high-dimensional eye movement data and hence, providing a strategy to identify similar eye movement patterns. The scatterplots can be used as means to interact with and to further annotate and analyze the data for additional properties focusing on space, time, or participants. Since t-SNE oftentimes produces groups of data points mapped to and overplotted in small scatterplot regions, we additionally support the modification of data point groups by a force-directed placement as a post processing in addition to t-SNE that can be run after the initial t-SNE algorithm is stopped. This spatial modification can be applied to each identified data point group independently which is difficult to integrate into a standard t-SNE approach. We illustrate the usefulness of our technique by applying it to formerly conducted eye tracking studies investigating the readability of public transport maps and map annotations.
-
(2018) : Visual Notifier. A Timeline-Based Visualization for Notifications from Several Environments In: Klein, Karsten; Li, Yi-Na (Hg.): The 11th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Växjö, 13. - 15. August: New York: Association for Computing Machinery (ACM), S. 114-115. Online verfügbar unter https://doi.org/10.1145/3231622.3231629, zuletzt geprüft am 09.09.2021
Abstract: In this paper we describe the visual notifier which is a timeline-based visualization that provides an overview about incoming notifications while it also supports an easier way to manage such notifications from several environments. Moreover, it is also possible to link them by certain subject types, author names or groups, or textual content. Such a visualization is in particular useful if there are too many notifications occurring in a short time period to answer and react on immediately, or to keep track of. The interactive visualization is implemented in Java and is easily extendable by additional functionality and interaction techniques. We illustrate theusefulness bytesting itforseveralemailaddresses andmessages from Facebook, Twitter, Ebay, Linkedin, and Researchgate.
-
(2018) : IMDb Explorer. Visual Exploration of a Movie Database In: Klein, Karsten; Li, Yi-Na (Hg.): The 11th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Växjö, 13. - 15. August: New York: Association for Computing Machinery (ACM), S. 88-91. Online verfügbar unter https://doi.org/10.1145/3231622.3231633, zuletzt geprüft am 09.09.2021
Abstract: Lots of movies are produced every year, too many to watch all of them and in particular, to get an overview about the evolution of typical movie genres and actors playing in them. Moreover, it is a challenging problem to detect correlations among the movies and the actors in those movies, in particular, if we are interested in time-varying data patterns like trends, countertrends, or anomalies and outliers. Those correlations are specifically interesting if they can be inspected on different levels of granularity, e.g., temporal, but also hierarchical in form of country- or continent-based correlations. In this paper we describe the IMDb Explorer, a web-based visualization tool that consists of two major views denoted by the movie cosmos and the career lines. Both views are linked and interactively manipulable while a list of user-defined metrics are explorable. We illustrate the usefulness of the visualization tool by applying it to the entire movie database provided by IMDb.
-
(2018) : Property-Driven Dynamic Call Graph Exploration In: Klein, Karsten; Li, Yi-Na (Hg.): The 11th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Växjö, 13. - 15. August: New York: Association for Computing Machinery (ACM), S. 72-79. Online verfügbar unter https://doi.org/10.1145/3231622.3231630, zuletzt geprüft am 09.09.2021
Abstract: Analyzing and visualizing call relations can provide useful insights into the connectivities and linkings of certain parts of a software system. This can in particular be a good strategy to find software system parts that are interlinked a lot while others typically occur as more or less stand-alone components not called by many others. The challenging problem with call relation data comes from the dynamics of the data, i.e., a call graph can be changing either during the development of a software system or during the execution of the software. The second case mostly leads to long graph sequences changing on a fine-granular temporal scale requiring a suitable overview-based dynamic graph visualization technique. Moreover, identifying certain temporal patterns in the graph evolution can help to detect certain phases of either the evolution of a software system or phases during the execution that can show which components are connected while someone interacts with the runnable software for example. This can particularly be based on graph, layout, or attribute properties, all providing different perspectives on the dynamics of the graph data. We illustrate the usefulness of our visualization technique by applying it to the open source software project JHotDraw. The call graphs are recorded during runtime while typical user interactions are applied.
-
(2018) : Challenges and Perspectives of Interacting with Hierarchy Visualizations on Large-Scale Displays In: Klein, Karsten; Li, Yi-Na (Hg.): The 11th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Växjö, 13. - 15. August: New York: Association for Computing Machinery (ACM), S. 33-40. Online verfügbar unter https://doi.org/10.1145/3231622.3231635, zuletzt geprüft am 09.09.2021
Abstract: In this paper we take a look into typical interaction scenarios when it comes to visualizing hierarchical data while we particularly focus on one specific candidate that is the visual depiction by generalized Pythagoras trees. Those are visualizations that benefit from their aesthetically appealing appearance since they come close to a visual model of trees growing in nature. Traditionally, those generalized Pythagoras trees are visualized on typical computer screens, clearly indicating the hierarchy, but negatively, the finer substructures are oftentimes not visible anymore due to the display space restriction and the low resolution. Hence, in this paper we describe the generalized Pythagoras trees displayed on largescale high-resolution displays and illustrate the challenges and perspectives when we have to interact with the visual representation by using the technique individually, but also in collaboration. To explore possible interactions we experimented with tablet computers combined with an optical tracking system. We evaluate the effectiveness and aesthetics by means of several modifiable visual parameters and by interacting with the visualization.
-
(2018) : EyeMSA. Exploring eye movement data with pairwise and multiple sequence alignment: Symposium on Eye Tracking Research and Applications: Proceedings: ETRA 2018: Warschau, 14. - 17. Juni: New York: Association for Computing Machinery (ACM), S. 52:1-52:5. Online verfügbar unter https://doi.org/10.1145/3204493.3204565, zuletzt geprüft am 09.09.2021
Abstract: Eye movement data can be regarded as a set of scan paths, each corresponding to one of the visual scanning strategies of a certain study participant. Finding common subsequences in those scan paths is a challenging task since they are typically not equally temporally long, do not consist of the same number of fixations, or do not lead along similar stimulus regions. In this paper we describe a technique based on pairwise and multiple sequence alignment to support a data analyst to see the most important patterns in the data. To reach this goal the scan paths are first transformed into a sequence of characters based on metrics as well as spatial and temporal aggregations. The result of the algorithmic data transformation is used as input for an interactive consensus matrix visualization. We illustrate the usefulness of the concepts by applying it to formerly recorded eye movement data investigating route finding tasks in public transport maps.
-
(2018): Visual Multi-Metric Grouping of Eye-Tracking Data. In: Journal of Eye Movement Research 10. Online verfügbar unter https://doi.org/10.16910/jemr.10.5.10, zuletzt geprüft am 09.09.2021
Abstract: We present an algorithmic and visual grouping of participants and eye-tracking metrics derived from recorded eye-tracking data. Our method utilizes two well-established visualization concepts. First, parallel coordinates are used to provide an overview of the used metrics, their interactions, and similarities, which helps select suitable metrics that describe characteristics of the eye-tracking data. Furthermore, parallel coordinates plots enable an analyst to test the effects of creating a combination of a subset of metrics resulting in a newly derived eye-tracking metric. Second, a similarity matrix visualization is used to visually represent the affine combination of metrics utilizing an algorithmic grouping of subjects that leads to distinct visual groups of similar behavior. To keep the diagrams of the matrix visualization simple and understandable, we visually encode our eyetracking data into the cells of a similarity matrix of participants. The algorithmic grouping is performed with a clustering based on the affine combination of metrics, which is also the basis for the similarity value computation of the similarity matrix. To illustrate the usefulness of our visualization, we applied it to an eye-tracking data set involving the reading behavior of metro maps of up to 40 participants. Finally, we discuss limitations and scalability issues of the approach focusing on visual and perceptual issues.
-
(2018) : Visual analysis of eye gazes to assist strategic planning in computer games In: Chuang, Lewis L.; Burch, Michael; Kurzhals, Kuno (Hg.): 3rd Workshop on Eye Tracking and Visualization: Proceedings: ETVIS '18: Warschau, 15. Juni: New York: Association for Computing Machinery (ACM), S. 6:1-6:5. Online verfügbar unter https://doi.org/10.1145/3205929.3205935, zuletzt geprüft am 09.09.2021
Abstract: This work studies the use of a conventional eye tracking system for analysis of an online game player's thinking processes. For this purpose, the eye gaze data of several users playing a simple online turn-based checkers game were recorded and made available in real-time to gaze-informed players. The motivation behind this work is to determine if making the eye-gaze data available can help these players to predict the gaze-tracked opponent player's further moves, and also how this can be most effectively done. We also tested different orientations of the screen on which the gaze data were displayed. By our visual and algorithmic analysis we validated (1) that prediction is possible and (2) that accuracy highly depends on the moves of players throughout the game as well as on the screen orientation. We believe that our study has implications on visual problem solving in general, especially in collaborative scenarios.
-
(2017): A Taxonomy and Survey of Dynamic Graph Visualization. In: Computer Graphics Forum 36, S. 133-159. Online verfügbar unter https://doi.org/10.1111/cgf.12791, zuletzt geprüft am 09.09.2021
Abstract: Dynamic graph visualization focuses on the challenge of representing the evolution of relationships between entities in readable, scalable and effective diagrams. This work surveys the growing number of approaches in this discipline. We derive a hierarchical taxonomy of techniques by systematically categorizing and tagging publications. While static graph visualizations are often divided into node-link and matrix representations, we identify the representation of time as the major distinguishing feature for dynamic graph visualizations: either graphs are represented as animated diagrams or as static charts based on a timeline. Evaluations of animated approaches focus on dynamic stability for preserving the viewer's mental map or, in general, compare animated diagrams to timeline-based ones. A bibliographic analysis provides insights into the organization and development of the field and its community. Finally, we identify and discuss challenges for future research. We also provide feedback from experts, collected with a questionnaire, which gives a broad perspective of these challenges and the current state of the field.
-
(2017): Visualization of Eye Tracking Data. A Taxonomy and Survey. In: Computer Graphics Forum 36, S. 260-284. Online verfügbar unter https://doi.org/10.1111/cgf.13079, zuletzt geprüft am 09.09.2021
Abstract: This survey provides an introduction into eye tracking visualization with an overview of existing techniques. Eye tracking is important for evaluating user behaviour. Analysing eye tracking data is typically done quantitatively, applying statistical methods. However, in recent years, researchers have been increasingly using qualitative and exploratory analysis methods based on visualization techniques. For this state-of-the-art report, we investigated about 110 research papers presenting visualization techniques for eye tracking data. We classified these visualization techniques and identified two main categories: point-based methods and methods based on areas of interest. Additionally, we conducted an expert review asking leading eye tracking experts how they apply visualization techniques in their analysis of eye tracking data. Based on the experts' feedback, we identified challenges that have to be tackled in the future so that visualizations will become even more widely applied in eye tracking research.
-
(2017): The dynamic graph wall. Visualizing evolving graphs with multiple visual metaphors. In: Journal of Visualization 20, S. 461-469. Online verfügbar unter https://doi.org/10.1007/s12650-016-0360-z, zuletzt geprüft am 09.09.2021
Abstract: Visualizing dynamic graphs is challenging due to the many data dimensions to be displayed such as graph vertices and edges with their attached weights or attributes and the additional time dimension. Moreover, edge directions with multiplicities and the graph topology are also important inherent features. However, in many dynamic graph visualization techniques each graph in a sequence is treated the same way, i.e., it is visually encoded in the same visual metaphor or even in the same layout. This visualization strategy can be problematic if the graphs are changing topologically over time, i.e., if a sparse graph becomes denser and denser over time or a star pattern is changing into a dense cluster of connected vertices. Such a dynamic graph data scenario demands for a visualization approach which is able to adapt the applied visual metaphor to each graph separately. In this paper we describe the dynamic graph wall to solve this problem by using multiple visual metaphors for dynamic graphs which are computed automatically by algorithms analysing each individual graph based on a given repertoire of graph features. The biggest issue in this technique for the graph dynamics, however, is the preservation of the viewer’s mental map at metaphor changes, i.e., to guide him through the graph changes with the goal to explore the data for time-varying patterns. To reach this goal we support the analyst by an interactive highlighting feature but we also display graphs in comparative metaphor rows to visually investigate the commonalities and differences over time.
-
(2017): Visual analytics of large dynamic digraphs. In: Information Visualization 16, S. 167-178. DOI: 10.1177/1473871616661194
DOI: https://doi.org/10.1177/1473871616661194 Abstract: In this article, we investigate the problem of visually representing and analyzing large dynamic directed graphs that consist of many vertices, edges, and time steps. With this work we do not primarily focus on graph details but more on achieving an overview about long graph sequences with the major focus to be scalable in vertex, edge, and time dimensions. To reach this goal, we first map each graph to a bipartite layout with vertices in the same order for each graph supporting a preservation of the viewer’s mental map. A sequence of graphs is placed in a left-to-right reading direction. To further reduce link crossings, we draw partial links with user-definable lengths and finally apply edge splatting as a concept to emphasize graph structures by color coding the generated density fields. Time-varying visual patterns can be recognized by inspecting the changes in the color coding in certain regions in the display. We illustrate the usefulness of the approach in two case studies investigating call graphs changing during software development with 21 releases which is a rather short graph sequence but contains several thousand vertices and edges. Visual scalability in the time dimension is shown with more than 1000 graphs from a dynamic social network dataset consisting of face-to-face contacts acquired during the Hypertext 2009 conference recorded by radio-frequency identification badges.
-
(2017): Visualizing a Sequence of a Thousand Graphs (or Even More). In: Computer Graphics Forum 36, S. 261-271. Online verfügbar unter https://doi.org/10.1111/cgf.13185, zuletzt geprüft am 09.09.2021
Abstract: The visualization of dynamic graphs demands visually encoding at least three major data dimensions: vertices, edges, and time steps. Many of the state-of-the-art techniques can show an overview of vertices and edges but lack a data-scalable visual representation of the time aspect. In this paper, we address the problem of displaying dynamic graphs with a thousand or more time steps. Our proposed interleaved parallel edge splatting technique uses a time-to-space mapping and shows the complete dynamic graph in a static visualization. It provides an overview of all data dimensions, allowing for visually detecting time-varying data patterns; hence, it serves as a starting point for further data exploration. By applying clustering and ordering techniques on the vertices, edge splatting on the links, and a dense time-to-space mapping, our approach becomes visually scalable in all three dynamic graph data dimensions. We illustrate the usefulness of our technique by applying it to call graphs and US domestic flight data with several hundred vertices, several thousand edges, and more than a thousand time steps.
-
(2017) : A Scalable Visualization for Dynamic Data in Software System Hierarchies: IEEE Working Conference on Software Visualization: Proceedings: VISSOFT: Shanghai, 18. - 19. September: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 85-93. Online verfügbar unter https://doi.org/10.1109/VISSOFT.2017.16, zuletzt geprüft am 10.09.2021
Abstract: Software systems can grow large, consisting of thousands of hierarchically organized elements like directories, subdirectories, files, and functions. Moreover, those hierarchy elements can carry additional information worth investigating for a software developer. Getting an overview of both the hierarchy and the attached static or dynamic data can become a tedious task if it is not supported by a visually scalable visualization technique. In this paper, we use a hierarchy visualization based on the visual metaphor of indentation to generate an overview of the software system hierarchy and easily attach additional attributes. The extra information is aligned with the hierarchy elements and, hence, supports visual comparisons of the attachments on different levels of hierarchical granularity. Through interaction, we provide additional views on the data, e.g., by filtering, hierarchy transformations, or details-on-demand. We illustrate the usefulness of our hierarchy visualization technique by means of an application example exploring data from the open-source software project jEdit. We investigated the readability of the hierarchy visualization with a user experiment, comparing indentation to node-link diagrams for varying sizes of a hierarchy.
-
(2017) : artVIS. An interactive visualization for painting collections In: Lie, Jie; Takahashi, Shigeo (Hg.): The 10th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Bangkok, 14. - 16. August: New York: Association for Computing Machinery (ACM), S. 109-112. Online verfügbar unter https://doi.org/10.1145/3105971.3105989, zuletzt geprüft am 09.09.2021
Abstract: Painting galleries typically provide a wealth of data composed of several data types. Those multivariate data are too complex for laymen like museum visitors to first, get an overview about all paintings and to look for specific categories. Finally, the goal is to guide the visitor to a specific painting that he wishes to have a more closer look on. In this paper we describe an interactive visualization tool that first provides such an overview and lets people experiment with the more than 41,000 paintings collected in the web gallery of art. To generate such an interactive tool, our technique is composed of different steps like data handling, algorithmic transformations, visualizations, interactions, and the human user working with the tool with the goal to detect insights in the provided data. We illustrate the usefulness of the visualization tool by applying it to such characteristic data and show how one can get from an overview about all paintings to specific paintings.
-
(2017) : Eye movement plots In: Lie, Jie; Takahashi, Shigeo (Hg.): The 10th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Bangkok, 14. - 16. August: New York: Association for Computing Machinery (ACM), S. 101-108. Online verfügbar unter https://doi.org/10.1145/3105971.3105973, zuletzt geprüft am 09.09.2021
Abstract: The visual analysis of eye movement data is a challenging task since the data has an inherent spatio-temporal nature and is typically recorded by measuring the eye movements of various study participants and sometimes, over long time periods. Finding similar strategies among the participants while applying a visual scanning strategy is one of the most important but also most difficult tasks. In this paper we describe the eye movement plots with which we are able to visually encode the eye movement fixation sequences of several study participants as a stacked line-based representation. The two-dimensional fixation points are mapped to a time-dependent sequence of lines while edge splatting is applied to visually augment the otherwise cluttered diagrams. With this visualization concept, time-varying eye movement patterns become visible, comparable, and generate an overview representation for a set of eye movements allowing comparison tasks. We illustrate the usefulness of the technique by means of applying it to formerly recorded eye tracking data by investigating route finding tasks in public transport systems. Moreover, we describe challenges, limitations, and scalability issues of the approach.
-
(2017) : Mining and visualizing eye movement data: SIGGRAPH Asia Symposium on Visualization: Proceedings: SA '17: Bangkok, 27. - 30. November: New York: Association for Computing Machinery (ACM), S. 3:1-3:8. Online verfügbar unter https://doi.org/10.1145/3139295.3139304, zuletzt geprüft am 09.09.2021
Abstract: Eye movement data has a spatio-temporal nature which makes the design of suitable visualization techniques a challenging task. Moreover, eye movement data is typically recorded by tracking the eyes of various study participants in order to achieve significant results about applied visual task solution strategies. If we have to deal with vast amounts of eye movement data, a data preprocessing in form of data mining is useful since it can be applied to compute a set of rules. Those aggregate, filter, and hence reduce the original data to derive patterns in it. The generated rule sets are still large enough to serve as input data for a visual analytics system. In this paper we describe a visual analysis model for eye movement data combining data mining and visualization with the goal to get an impression about point-of-interest (POI) and area-of-interest (AOI) correlations in eye movement data on different levels of spatial and temporal granularities. Those correlations can support a data analyst to derive visual patterns that can be mapped to data patterns, i.e., visual scanning strategies with different probabilities of a group of eye tracked people. We show the usefulness of our data mining and visualization system by applying it to datasets recorded in a formerly conducted eye tracking experiment investigating the readability of metro maps.
-
(2017) : Dynamic Graph Visualization on Different Temporal Granularities: Information Visualisation: Computer Graphics, Imaging and Visualisation Informat ion Visua l isa t i on Computer Graphics, Imaging and Visualisation. Biomedical Visualization, Visualisation on Built and Rural Environments & Geometric Modelling and Imaging: Proceedings: 21st International Conference on Information Visualisation (IV): London, 11. - 14. Juli: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 230-235. Online verfügbar unter https://doi.org/10.1109/iV.2017.44, zuletzt geprüft am 09.09.2021
Abstract: Dynamic graphs are typically represented in a time-to-space mapping with the goal to preserve the mental map in order to reduce cognitive efforts for comparison tasks. Such a mapping from time to space has the general drawback that space limitations are sooner reached than in corresponding time-to-time mappings to which graph animation belongs. Consequently, to get an overview about the dynamics in a graph sequence, space-efficient and compact visual encodings are used to show as many graphs in the sequence as possible. Temporal graph aggregation is hence a clever data transformation strategy, but negatively, it does not provide an overview about individual graphs nor does it show graph subsequences on finer time granularities. In this paper we describe a visualization technique that can visualize dynamic graphs in a time-to-space mapping and additionally, allows the graph analyst to interactively explore the dynamic graph data on different temporal granularities. Moreover, if the dynamic graph data is rather dense, it can be filtered by selecting density intervals. We illustrate the usefulness of our visualization tool by applying it to a dynamic graph dataset that simulates time-continuously changing graphs.
-
(2017) : A User Study on Judging the Target Node in Partial Link Drawings: Information Visualisation: Computer Graphics, Imaging and Visualisation Informat ion Visua l isa t i on Computer Graphics, Imaging and Visualisation. Biomedical Visualization, Visualisation on Built and Rural Environments & Geometric Modelling and Imaging: Proceedings: 21st International Conference on Information Visualisation (IV): London, 11. - 14. Juli: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 199-204. Online verfügbar unter https://doi.org/10.1109/iV.2017.43, zuletzt geprüft am 09.09.2021
Abstract: Partially drawn links are a possibility to reduce visual clutter in node-link visualizations of relational data caused by link crossings. Although partial links have some benefits concerning task performance, they exhibit issues regarding target node ambiguities. In this paper, we provide the results of a user study that investigates the performance in terms of task accuracy when judging target nodes to which partial links are pointing. We vary the link lengths and link directions as independent variables and measure the task accuracy as dependent variable while the exposure duration for each stimulus is fixed. The major result of our user study is that people tend to make more target node judgment errors with shorter link lengths. Moreover, the direction of the partial links also has an impact on the accuracy. With these results, we are able to choose appropriate parameter settings for graphs drawn with partial links. This can be regarded as a novel graph drawing criterion for improving the readability of graphs represented with partial links.
-
(2017) : A Task-Based View on the Visual Analysis of Eye-Tracking Data In: Burch, Michael; Chuang, Lewis; Fisher, Brian; Schmidt, Albrecht; Weiskopf, Daniel (Hg.): Eye Tracking and Visualization: Foundations, Techniques, and Applications: ETVIS: Chicago, 25. Oktober 2015: Cham: Springer International Publishing (Mathematics and Visualization), S. 3-22
DOI: https://doi.org/10.1007/978-3-319-47024-5_1 Abstract: The visual analysis of eye movement data has become an emerging field of research leading to many new visualization techniques in recent years. These techniques provide insight beyond what is facilitated by traditional attention maps and gaze plots, providing important means to support statistical analysis and hypothesis building. There is no single “all-in-one” visualization to solve all possible analysis tasks. In fact, the appropriate choice of a visualization technique depends on the type of data and analysis task. We provide a taxonomy of analysis tasks that is derived from literature research of visualization techniques and embedded in our pipeline model of eye-tracking visualization. Our task taxonomy is linked to references to representative visualization techniques and, therefore, it is a basis for choosing appropriate methods of visual analysis. We also elaborate on how far statistical analysis with eye-tracking metrics can be enriched by suitable visualization and visual analytics techniques to improve the extraction of knowledge during the analysis process.
-
(2017): An Evaluation of Visual Search Support in Maps. In: IEEE Transactions on Visualization and Computer Graphics 23, S. 421-430. Online verfügbar unter https://doi.org/10.1109/TVCG.2016.2598898, zuletzt geprüft am 09.09.2021
Abstract: Visual search can be time-consuming, especially if the scene contains a large number of possibly relevant objects. An instance of this problem is present when using geographic or schematic maps with many different elements representing cities, streets, sights, and the like. Unless the map is well-known to the reader, the full map or at least large parts of it must be scanned to find the elements of interest. In this paper, we present a controlled eye-tracking study (30 participants) to compare four variants of map annotation with labels: within-image annotations, grid reference annotation, directional annotation, and miniature annotation. Within-image annotation places labels directly within the map without any further search support. Grid reference annotation corresponds to the traditional approach known from atlases. Directional annotation utilizes a label in combination with an arrow pointing in the direction of the label within the map. Miniature annotation shows a miniature grid to guide the reader to the area of the map in which the label is located. The study results show that within-image annotation is outperformed by all other annotation approaches. Best task completion times are achieved with miniature annotation. The analysis of eye-movement data reveals that participants applied significantly different visual task solution strategies for the different visual annotations.
-
(2017): User performance and reading strategies for metro maps. An eye tracking study. In: Spatial Cognition & Computation 17, S. 39-64. Online verfügbar unter https://doi.org/10.1080/13875868.2016.1226839, zuletzt geprüft am 09.09.2021
Abstract: We conducted a controlled empirical eye tracking study with 40 participants using schematic metro maps. The study focused on two aspects: determining different reading strategies and assessing user performance. We considered the following factors: color encoding (color vs. gray-scale), map complexity (three levels), and task difficulty (three levels). There was one type of task: find a route from a start to a target location and state the number of transfers that have to be performed. To identify reading strategies, we annotated fixations of scanpaths, computed a transition matrix of each annotated scanpath, and used these matrices as input to cluster scanpaths into groups of similar behavior. We show how these reading strategies relate to the geodesic structure of the scanpaths' fixations projected onto the geodesic line that connects start and target locations. The analysis of the eye tracking data is complemented by statistical inference working on two eye tracking metrics (average fixation duration and saccade length). User performance was evaluated with a statistical analysis of task correctness and completion time. Our study shows that the design factors have a significant impact on user task performance. Also, we were able to identify typical reading strategies like directly finding a path from start to target location. Often, participants check the correctness of their result multiple times by moving back and forth between start and target. Our findings also indicate that the choice of reading strategies does not depend on whether color or gray-scale encoding is used.
-
(2017) : Visualization of time series data with spatial context. Communicating the energy production of power plants In: Lie, Jie; Takahashi, Shigeo (Hg.): The 10th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Bangkok, 14. - 16. August: New York: Association for Computing Machinery (ACM), S. 37-44. Online verfügbar unter https://doi.org/10.1145/3105971.3105982, zuletzt geprüft am 09.09.2021
Abstract: Visualizing time series data with a spatial context is a problem that appears more and more often, since small and lightweight GPS devices allow us to enrich the time series data with position information. One example is the visualization of the energy output of power plants. We present a web-based application that aims to provide information about the energy production of a specified region, along with location information about the power plants. The application is intended to be used as a solid data basis for political discussions, nudging, and story telling about the German energy transition to renewables, called "Energiewende". It was therefore designed to be intuitive, easy to use, and provide information for a broad spectrum of users that do not need any domain-specific knowledge. Users are able to select different categories of power plants and look up their positions on an overview map. Glyphs indicate their exact positions and a selection mechanism allows users to compare the power output on different time scales using stacked area charts or ThemeRivers. As an evaluation of the application, we have collected web access statistics and conducted an online survey with respect to the intuitiveness, usability, and informativeness.
-
(2017) : A Visual Analytics Approach for Word Relevances in Multiple Texts: Information Visualisation: Computer Graphics, Imaging and Visualisation Informat ion Visua l isa t i on Computer Graphics, Imaging and Visualisation. Biomedical Visualization, Visualisation on Built and Rural Environments & Geometric Modelling and Imaging: Proceedings: 21st International Conference on Information Visualisation (IV): London, 11. - 14. Juli: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 1-7. Online verfügbar unter https://doi.org/10.1109/iV.2017.62, zuletzt geprüft am 09.09.2021
Abstract: We investigate the problem of analyzing word frequencies in multiple text sources with the aim to give an overview of word-based similarities in several texts as a starting point for further analysis. To reach this goal, we designed a visual analytics approach composed of typical stages and processes, combining algorithmic analysis, visualization techniques, the human users with their perceptual abilities, as well as interaction methods for both the data analysis and the visualization component. By our algorithmic analysis, we first generate a multivariate dataset where words build the cases and the individual text sources the attributes. Real-valued relevances express the significances of each word in each of the text sources. From the visualization perspective, we describe how this multivariate dataset can be visualized to generate, confirm, rebuild, refine, or reject hypotheses with the goal to derive meaning, knowledge, and insights from several text sources. We discuss benefits and drawbacks of the visualization approaches when analyzing word relevances in multiple texts.
-
(2017) : Visual Data Cleansing of Low-Level Eye-Tracking Data In: Burch, Michael; Chuang, Lewis; Fisher, Brian; Schmidt, Albrecht; Weiskopf, Daniel (Hg.): Eye Tracking and Visualization: Foundations, Techniques, and Applications: ETVIS: Chicago, 25. Oktober 2015: Cham: Springer International Publishing (Mathematics and Visualization), S. 199-216
DOI: https://doi.org/10.1007/978-3-319-47024-5_12 Abstract: Analysis and visualization of eye movement data from eye-tracking studies typically take into account gazes, fixations, and saccades of both eyes filtered and fused into a combined eye. Although this is a valid strategy, we argue that it is also worth investigating low-level eye-tracking data prior to high-level analysis, because today’s eye-tracking systems measure and infer data from both eyes separately. In this work, we present an approach that supports visual analysis and cleansing of low-level time-varying data for eye-tracking experiments. The visualization helps researchers get insights into the quality of the data in terms of its uncertainty, or reliability. We discuss uncertainty originating from eye tracking, and how to reveal it for visualization, using a comparative approach for disagreement between plots, and a density-based approach for accuracy in volume rendering. Finally, we illustrate the usefulness of our approach by applying it to eye movement data recorded with two state-of-the-art eye trackers.
-
(2016) : A Matrix-Based Visual Comparison of Time Series Sports Data: Vision, Modeling, and Visualization: Proceedings: VMV 2016: Bayreuth, 10. - 12. Oktober: Goslar: Eurographics Association, S. 53-60. Online verfügbar unter http://dx.doi.org/10.2312/vmv.20161342, zuletzt geprüft am 10.09.2021
Abstract: In sports, large amounts of data are measured and stored with the help of modern sensors and electronic devices. In particular, for endurance sports events, time-varying data are recorded and can be used to analyze the athletes' performance. Finding patterns and issues can help better understand results in sports competitions, which is of interest for the athletes, sports managers, and trainers alike. In this paper, we introduce a matrix-based approach to visually compare similar and dissimilar periods in performances of athletes. We differentiate the performances and visually encode these differences as color-coded matrix cells. The strengths of our approach are illustrated in a case study investigating the performances of two riders in the prologue of Tour de France 2012.
-
(2016) : Visual analysis of compound graphs In: Blackwell, Alan; Plimmer, Beryl; Stapleton, Gem (Hg.): Symposium on Visual Languages and Human Centric Computing: Proceedings: VL/HCC: Cambridge, 4. - 8. September: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 54-58. Online verfügbar unter https://doi.org/10.1109/VLHCC.2016.7739664, zuletzt geprüft am 10.09.2021
Abstract: Compound graphs consist of two separate components. On the one hand a graph structure describes which elements are related to each other and to what extent, i.e., inherent edge weights and directions may exist, which we refer to as adjacency edges. On the other hand the graph elements are not only related by adjacencies, but they are also hierarchically organized which might be considered another kind of relationship among the graph vertices. Those relations are further referred to as inclusion edges. There are various application domains in which such a data structure occurs and with which a data analyst has to deal, either analytically on the basis of algorithms or visually, i.e., more on the basis of diagrams and visual languages. In this paper we introduce a visualization tool that is able to provide linked views on both aspects, i.e., the graph relations and the hierarchical organization. We illustrate the usefulness of our tool in a case study investigating soccer team results that build weighted directed adjacency relations in a hierarchically structured world.
-
(2016) : The Dynamic Call Graph Matrix In: Kerren, Andreas; Zhang, Kang (Hg.): The 9th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Dallas, 24. - 26. September: New York: Association for Computing Machinery (ACM), S. 1-8. Online verfügbar unter https://doi.org/10.1145/2968220.2968226, zuletzt geprüft am 10.09.2021
Abstract: Visualizing dynamic call graphs is typically done by providing a visual representation that shows the sequence of static graphs placed next to each other. Such a time-to-space mapping is useful to visually compare the graphs and to see the changing graph structure, but, negatively, a view on changes between all pairs of graphs in the sequence is not provided and detecting similarities of longer call graph subsequences is not well supported. In this paper we describe the dynamic call graph matrix that shows similarities and differences between graph pairs in a graph sequence by applying certain well-known set operations as well as fine-grained and coarse-grained graph views supporting visual scalability. We illustrate the usefulness of our technique by applying it to dynamic call graph data from the open source software project JUnit that contains several inherent dynamic call graph features worth investigating and hard to find by a side-by-side dynamic graph visualization alone.
-
(2016) : Lyrics Word Clouds: Information Visualisation: Computer Graphics, Imaging and Visualisation. Biomedical Visualization, Visualisation on Built and Rural Environments & Geometric Modelling and Imaging: Proceedings: 20th International Conference on Information Visualisation (IV): Lissabon, 19. - 22. Juli: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 51-56. Online verfügbar unter https://doi.org/10.1109/IV.2016.27, zuletzt geprüft am 10.09.2021
Abstract: Plenty of songs are composed, written, and releasedevery year being recorded in a variety of databases. Thosedo not only store the audio, but also additional data like theartists' names, the years of release, the lengths of the songs, or number of visits, comments, and remarks of visitors andthe like. However, another important data is the lyrics, i.e., thetextual content which can give insights about the topic, genre, or intention of the musicians. Getting an overview about thetextual content of a song, i.e., the lyrics can become a tediouschallenge since listening to the songs or reading the texts is a timeconsuming task. To support users of song databases we propose a visualization tool that is able to generate word clouds from lyrics. Interaction techniques are incorporated in the tool to give more detailed information about the occurrence of words in a song that finally help to find insights about the genre or to just compare the content very rapidly, for example. Our visualization tool is implemented as a web-based interface, that stores requests, updates the local tool database based on those requests, and finally, provides an interactive visualization for the user.
-
(2016) : Isoline-Enhanced Dynamic Graph Visualization: Information Visualisation: Computer Graphics, Imaging and Visualisation. Biomedical Visualization, Visualisation on Built and Rural Environments & Geometric Modelling and Imaging: Proceedings: 20th International Conference on Information Visualisation (IV): Lissabon, 19. - 22. Juli: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 1-8. Online verfügbar unter https://doi.org/10.1109/IV.2016.28, zuletzt geprüft am 10.09.2021
Abstract: Static or dynamic graphs are typically visualized by either node-link diagrams, adjacency matrices, adjacency lists, orhybrids thereof. In particular, for the case of a changing graphstructure a viewer wishes to be able to visually compare thegraphs in a sequence. Doing such a comparison task rapidlyand reliably can give support to visually analyze the dynamicgraph for certain dynamic patterns. In this paper we describe a novel dynamic graph visualization that is based on the concept of smooth density fields generated by first splatting the links of a given graph in a certain layout. To further visually enhance the time-varying graph structures we add user-adaptable isolines to the resulting dynamic graph representation. The computed visual encoding of the dynamic graph is aesthetically appealing due to its smooth curves and can additionally be used to do comparisons in a long graph sequence, i.e., from an information visualization perspective it serves as an overview representation supporting to start more detailed analyses processes. To demonstrate theusefulness of the technique we explore real-world dynamic graph data by taking into account visual parameters like node-link layouts, smoothing iterations, number of isolines, and different color codings.
-
(2016) : The Challenges of Designing Metro Maps In: Magnenat-Thalmann, Nadia; Richard, Paul; Linsen, Lars; Telea, Alexandru; Battiato, Sebastiano; Imai, Francisco; Braz, Jose (Hg.): 11th Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications: Proceedings. Volume 2: VISIGRAPP 2016: Rom, 27. - 29. Februar: Setúbal: SciTePress, S. 195-202. Online verfügbar unter https://doi.org/10.5220/0005679601950202, zuletzt geprüft am 10.09.2021
Abstract: Metro maps can be regarded as a particular version of information visualization. The goal is to produce readable and effective map designs. In this paper, we combine the expertise of design experts and visualization researchers to achieve this goal. The aesthetic design of the maps should play a major role as the intention of the designer is to make them attractive for the human viewer in order to use the designs in a way that is the most efficient. The designs should invoke accurate actions by the user—in the case of a metro map, the user would be making journeys. We provide two views on metro map designs: one from a designer point of view and one from a visualization expert point of view. The focus of this work is to find a combination of both worlds from which the designer as well as the visualizer can benefit. To reach this goal we first describe the designer’s work when designing metro maps, then we take a look at how a visualizer measures performance from an end user perspectiv e by tracking people’s eyes when working with the formerly designed maps while answering a route finding task.
-
(2016) : Color bands. Visualizing dynamic eye movement patterns In: Burch, Michael; Chuang, Lewis L.; Duchowski, Andrew (Hg.): 2nd Workshop on Eye Tracking and Visualization: Proceedings: ETVIS 2016: Baltimore, 23. Oktober: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 40-44. Online verfügbar unter https://doi.org/10.1109/ETVIS.2016.7851164, zuletzt geprüft am 10.09.2021
Abstract: We introduce a visualization technique called color bands for showing the time-varying eye movement behavior of eye-tracked people. Our contribution is the clutter-free representation of time-varying x- and y-positions of gaze data. We map these coordinates to vertical positions from left to right as in traditional line plots. On top, we display the differences between the x- and y-coordinates by the thickness of the band. Fixation durations are visually encoded as circles of varying diameters. Color coding is used to additionally enhance the distance values and the durations in order to perceptually benefit from pattern recognition for an individual participant but also to compare the eye movement behavior of several participants. We illustrate the usefulness of our technique in a case study investigating eye movements from a formerly conducted eye tracking study on the readability of node-link tree diagrams.
-
(2016) : Multi-similarity matrices of eye movement data In: Burch, Michael; Chuang, Lewis L.; Duchowski, Andrew (Hg.): 2nd Workshop on Eye Tracking and Visualization: Proceedings: ETVIS 2016: Baltimore, 23. Oktober: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 26-30. Online verfügbar unter https://doi.org/10.1109/ETVIS.2016.7851161, zuletzt geprüft am 10.09.2021
Abstract: We describe a matrix-based visualization technique for algorithmically and visually comparing metrics in eye movement data. To reach this goal, a set of scanpath trajectories is first preprocessed and transformed into a set of metrics describing commonalities and differences of eye movement trajectories. To keep the generated diagrams simple, understandable, and free of visual clutter we visually encode the generated dataset into the cells of a matrix. Apart from just incorporating one individual metric of the dataset into a matrix cell, we extend this standard visualization by a dimensional-stacking approach supporting the display of several of those metrics integrated into one matrix cell. To further improve the readability and pattern finding among those values, our approach supports a metric-based clustering and further interaction techniques to manipulate the data and to navigate in it. To illustrate the usefulness of the system, we applied it to an eye movement dataset about the reading behavior of metro maps. Finally, we discuss limitations and scalability issues of the approach.
-
(2016): Gaze Stripes. Image-Based Visualization of Eye Tracking Data. In: IEEE Transactions on Visualization and Computer Graphics 22, S. 1005-1014. Online verfügbar unter https://doi.org/10.1109/TVCG.2015.2468091, zuletzt geprüft am 10.09.2021
Abstract: We present a new visualization approach for displaying eye tracking data from multiple participants. We aim to show the spatio-temporal data of the gaze points in the context of the underlying image or video stimulus without occlusion. Our technique, denoted as gaze stripes, does not require the explicit definition of areas of interest but directly uses the image data around the gaze points, similar to thumbnails for images. A gaze stripe consists of a sequence of such gaze point images, oriented along a horizontal timeline. By displaying multiple aligned gaze stripes, it is possible to analyze and compare the viewing behavior of the participants over time. Since the analysis is carried out directly on the image data, expensive post-processing or manual annotation are not required. Therefore, not only patterns and outliers in the participants' scanpaths can be detected, but the context of the stimulus is available as well. Furthermore, our approach is especially well suited for dynamic stimuli due to the non-aggregated temporal mapping. Complementary views, i.e., markers, notes, screenshots, histograms, and results from automatic clustering, can be added to the visualization to display analysis results. We illustrate the usefulness of our technique on static and dynamic stimuli. Furthermore, we discuss the limitations and scalability of our approach in comparison to established visualization techniques.
-
(2016): Eye tracking evaluation of visual analytics. In: Information Visualization 15, S. 340-358. DOI: 10.1177/1473871615609787
DOI: https://doi.org/10.1177/1473871615609787 Abstract: The application of eye tracking for the evaluation of humans’ viewing behavior is a common approach in psychological research. So far, the use of this technique for the evaluation of visual analytics and visualization is less prominent. We investigate recent scientific publications from the main visualization and visual analytics conferences and journals, as well as related research fields that include an evaluation by eye tracking. Furthermore, we provide an overview of evaluation goals that can be achieved by eye tracking and state-of-the-art analysis techniques for eye tracking data. Ideally, visual analytics leads to a mixed-initiative cognitive system where the mechanism of distribution is the interaction of the user with the visualization environment. Therefore, we also include a discussion of cognitive approaches and models to include the user in the evaluation process. Based on our review of the current use of eye tracking evaluation in our field and the cognitive theory, we propose directions for future research on evaluation methodology, leading to the grand challenge of developing an evaluation approach to the mixed-initiative cognitive system of visual analytics.
-
(2016) : Fixation-image charts: Symposium on Eye Tracking Research and Applications: Proceedings: ETRA 2016: Charleston, 14. - 17. März: New York: Association for Computing Machinery (ACM), S. 11-18. Online verfügbar unter https://doi.org/10.1145/2857491.2857507, zuletzt geprüft am 10.09.2021
Abstract: We facilitate the comparative visual analysis of eye tracking data from multiple participants with a visualization that represents the temporal changes of viewing behavior. Common approaches to visually analyze eye tracking data either occlude or ignore the underlying visual stimulus, impairing the interpretation of displayed measures. We introduce fixation-image charts: a new technique to display the temporal changes of fixations in the context of the stimulus without visual overlap between participants. Fixation durations, the distance and direction of saccades between consecutive fixations, as well as the stimulus context can be interpreted in one visual representation. Our technique is not limited to static stimuli, but can be applied to dynamic stimuli as well. Using fixation metrics and the visual similarity of stimulus regions, we complement our visualization technique with an interactive filter concept that allows for the identification of interesting fixation sequences without the time-consuming annotation of areas of interest. We demonstrate how our technique can be applied to different types of stimuli to perform a range of analysis tasks. Furthermore, we discuss advantages and shortcomings derived from a preliminary user study.
-
(2016) : Interactive scanpath-oriented annotation of fixations: Symposium on Eye Tracking Research and Applications: Proceedings: ETRA 2016: Charleston, 14. - 17. März: New York: Association for Computing Machinery (ACM), S. 183-187. Online verfügbar unter https://doi.org/10.1145/2857491.2857498, zuletzt geprüft am 10.09.2021
Abstract: In this short paper, we present a lightweight application for the interactive annotation of eye tracking data for both static and dynamic stimuli. The main functionality is the annotation of fixations that takes into account the scanpath and stimulus. Our visual interface allows the annotator to work through a sequence of fixations, while it shows the context of the scanpath in the form of previous and subsequent fixations. The context of the stimulus is included as visual overlay. Our application supports the automatic initial labeling according to areas of interest (AOIs), but is not dependent on AOIs. The software is easily configurable, supports user-defined annotation schemes, and fits in existing workflows of eye tracking experiments and the evaluation thereof by providing import and export functionalities for data files.
-
(2015) : Generalized Pythagoras Trees. A Fractal Approach to Hierarchy Visualization In: Battiato, Sebastiano; Coquillart, Sabine; Pettré, Julien; Laramee, Robert S.; Kerren, Andreas; Braz, Jose (Hg.): 9th Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications: Proceedings: VISIGRAPP 2014: Lissabon, 5. - 8. Januar 2014: Cham: Springer International Publishing (Communications in Computer and Information Science), S. 115-135
DOI: https://doi.org/10.1007/978-3-319-25117-2_8 Abstract: Through their recursive definition, many fractals have an inherent hierarchical structure. An example are binary branching Pythagoras Trees. By stopping the recursion in certain branches, a binary hierarchy can be encoded and visualized. But this binary encoding is an obstacle for representing general hierarchical data such as file systems or phylogenetic trees, which usually branch into more than two subhierarchies. We hence extend Pythagoras Trees to arbitrarily branching trees by adapting the geometry of the original fractal approach. Each vertex in the hierarchy is visualized as a rectangle sized according to a metric. We analyze several visual parameters such as length, width, order, and color of the nodes against the use of different metrics. Interactions help to zoom, browse, and filter the hierarchy. The usefulness of our technique is illustrated by two case studies visualizing directory structures and a large phylogenetic tree. We compare our approach with existing tree diagrams and discuss questions of geometry, perception, readability, and aesthetics.
-
(2015) : Challenges and Perspectives in Big Eye-Movement Data Visual Analytics: Big Data Visual Analytics: Proceedings: BDVA: Hobart, 22. - 25. September: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 17-24. Online verfügbar unter https://doi.org/10.1109/BDVA.2015.7314288, zuletzt geprüft am 10.09.2021
Abstract: Eye tracking has become an important technology to understand where and when people pay visual attention to a scene. Nowadays, eye tracking technology is moving from the laboratory to the real-world, producing more data at higher rates with extensive amounts of different data types. If this trend continues, eye tracking moves into the direction of big data. This requires developing new evaluation approaches beyond statistical analysis and visual inspection to find patterns in the data. As in big data analysis, visual analytics is one possible direction for eye movement data analysis. We look at current visual analytics methods and discuss how they can be applied to big eye-movement data. In this position paper we describe challenges for big eye-movement data visual analytics and discuss which techniques may be useful to address these challenges. Finally, we describe a number of potential scenarios for big eye-movement data.
-
(2015): Eye Tracking Visualization. Tutorial (Eurographics Tutorials). Online verfügbar unter https://diglib.eg.org/handle/10.2312/egt.20151044.t2, zuletzt geprüft am 10.09.2021
Abstract: Eye tracking has become a widely used method to analyze user behavior in marketing, neuroscience, human-computer interaction, and visualization research. Apart from measuring completion times and recording accuracy rates of correctly given answers during the performance of visual tasks in classical controlled user experiments, eye tracking-based evaluations provide additional information on how visual attention is distributed and changing for a presented stimulus. Due to the wide field of applications of eye tracking and various kinds of research questions, different approaches have been developed to analyze eye tracking data such as statistical algorithms (either descriptive or inferential), string editing algorithms, visualization-related techniques, and visual analytics techniques. Regardless of whether statistical or visual methods are used for eye tracking data analysis, a large amount of data generated during eye tracking experiments has to be handled.
-
(2015): Flip-Book Visualization of Dynamic Graphs. In: International Journal of Software and Informatics 9, S. 3-21. Online verfügbar unter http://www.ijsi.org/ch/reader/view_abstract.aspx?file_no=i205, zuletzt geprüft am 10.09.2021
Abstract: Dynamic graph visualization techniques can be based on animated or static diagrams showing the evolution over time. In this paper, we apply the concept of small multiples to visually illustrate the dynamics of a graph. Node-link, adjacency matrix, and adjacency list visualizations are used as basic visual metaphors for displaying individual graphs of the sequence. For node-link diagrams, we apply edge splatting to improve readability and reduce visual clutter caused by overlaps and link crossings. Additionally, to obtain a more scalable dynamic graph visualization in the time dimension, we integrate an interactive Rapid Serial Visual Presentation (RSVP) feature to rapidly °ip between the sequences of displayed graphs, similar to the concept of flipping a book's pages. Our visualization tool supports the focus-and-context design principle by providing an overview of a longer time sequence as small multiples in a grid while also showing a graph in focus as a large single representation in a zoomed in and more detailed view. The usefulness of the technique is illustrated in two case studies investigating a dynamic directed call graph and an evolving social network that consists of more than 1,000 undirected graphs.
-
(2015) : Visualizing work processes in software engineering with developer rivers: IEEE Working Conference on Software Visualization: Proceedings: VISSOFT: Bremen, 27. - 28. September: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 116-124. Online verfügbar unter https://doi.org/10.1109/VISSOFT.2015.7332421, zuletzt geprüft am 10.09.2021
Abstract: Work processes involving dozens or hundreds of collaborators are complex and difficult to manage. Problems within the process may have severe organizational and financial consequences. Visualization helps monitor and analyze those processes. In this paper, we study the development of large software systems as an example of a complex work process. We introduce Developer Rivers, a timeline-based visualization technique that shows how developers work on software modules. The flow of developers' activity is visualized by a river metaphor: activities are transferred between modules represented as rivers. Interactively switching between hierarchically organized modules and workload metrics allows for exploring multiple facets of the work process. We study typical development patterns by applying our visualization to Python and the Linux kernel.
-
(2015) : Dynamic Graph Visualization with Multiple Visual Metaphors In: Bottoni, Paolo; Takahashi, Shigeo; Itoh, Takayuki (Hg.): The 8th International Symposium on Visual Information Communication and Interaction: Proceedings: VINCI: Tokyo, 24. - 26. August: New York: Association for Computing Machinery (ACM), S. 27-34. Online verfügbar unter https://doi.org/10.1145/2801040.2801048, zuletzt geprüft am 10.09.2021
Abstract: Visualizing dynamic graphs is challenging due to the many data dimensions to be displayed such as graph vertices and edges with their attached weights or attributes and the additional time dimension. Moreover, edge directions with multiplicities and the graph topology are also important inherent features. However, in many dynamic graph visualization techniques each graph in a sequence is treated the same way, i.e., it is visually encoded in the same visual metaphor or even in the same layout. This visualization strategy can be problematic if the graphs are changing topologically over time, i.e., if a sparse graph becomes denser and denser over time or a star pattern is changing into a dense cluster of connected vertices. Such a dynamic graph data scenario demands for a visualization approach which is able to adapt the applied visual metaphor to each graph separately. In this paper we show an idea to solve this problem by using multiple visual metaphors for dynamic graphs which are computed automatically by algorithms analyzing each individual graph based on a given repertoire of graph features. The biggest issue in this technique for the graph dynamics, however, is the preservation of the viewer's mental map at metaphor changes, i.e., to guide him through the graph changes with the goal to explore the data for time-varying patterns. To reach this goal we support the analyst by an interactive highlighting feature.
-
(2015) : Visualizing the Evolution of Ontologies. A Dynamic Graph Perspective In: Ivanova, Valentina, Lambrix, Patrick; Lohmann, Steffen; Pesquita, Catia (Hg.): Visualizations and User Interfaces for Ontologies and Linked Data: Proceedings: VOILA: Bethlehem, Pennsylvania, 11. Oktober, S. 69-76. Online verfügbar unter http://ceur-ws.org/Vol-1456/, zuletzt geprüft am 10.09.2021
Abstract: Ontologies can be represented as graphs, since they essentially comprise a set of interconnected concepts describing a certain field of knowledge. Consequently, ontologies are often visualized as graphs, using different visual notations and common graph drawing techniques. The visualization of static graphs has been researched a lot, but when it comes to time-varying graphs, researchers face much more challenges in order to design useful, readable, and intuitive visualizations. If we have to deal with dynamic, i.e., evolving and time-dependent ontologies, we have to adapt existing visualization techniques to this challenging problem or develop new ones. In this position paper, we take a look at the visual representation of time-varying ontologies, and provide a discussion from a dynamic graph visualization perspective.
-
(2015) : An Analysis and Visualization Tool for DBLP Data: Information Visualisation: Computer Graphics, Imaging and Visualisation. Biomedical Visualization, Visualisation on Built and Rural Environments & Geometric Modelling and Imaging: Proceedings: 19th International Conference on Information Visualisation (IV): Barcelona, 22. - 24. Juli: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 163-170. Online verfügbar unter https://doi.org/10.1109/iV.2015.38, zuletzt geprüft am 10.09.2021
Abstract: The Digital Bibliography and Library Project (DBLP) is a popular computer science bibliography website hosted at the University of Trier in Germany. It currently contains 2,722,212 computer science publications with additional information about the authors and conferences, journals, or books in which these are published. Although the database covers the majority of papers published in this field of research, it is still hard to browse the vast amount of textual data manually to find insights and correlations in it, in particular time-varying ones. This is also problematic if someone is merely interested in all papers of a specific topic and possible correlated scientific words which may hint at related papers. To close this gap, we propose an interactive tool which consists of two separate components, namely data analysis and data visualization. We show the benefits of our tool and explain how it might be used in a scenario where someone is confronted with the task of writing a state-of-the art report on a specific topic. We illustrate how data analysis, data visualization, and the human user supported by interaction features can work together to find insights which makes typical literature search tasks faster.
-
(2015) : Visual Analysis of Source Code Similarities: Information Visualisation: Computer Graphics, Imaging and Visualisation. Biomedical Visualization, Visualisation on Built and Rural Environments & Geometric Modelling and Imaging: Proceedings: 19th International Conference on Information Visualisation (IV): Barcelona, 22. - 24. Juli: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 21-27. Online verfügbar unter https://doi.org/10.1109/iV.2015.16, zuletzt geprüft am 10.09.2021
Abstract: Software systems typically consist of many lines of source code organized in several files hierarchically structured into directories and packages. Since the code is the key data in software development, in many scenarios an overview of it is required, in particular for similar code passages. In this paper, we investigate the visual analysis of source code similarities for local as well as global code passages. To this end, we first compute all subsequence occurrence frequencies (support metric) and relative occurrence frequencies (confidence metric) in local as well as global code regions. The resulting textual data attached by its occurrence values is displayed in a triangular matrix. Several interaction techniques are integrated in our visualization tool which are illustrated in the corresponding case study illustrating similarities in source code written in Assembler consisting of 10,641 characters.
-
(2015) : Visualizing Software Metrics in a Software System Hierarchy In: Bebis, George; Boyle, Richard; Parvin, Bahram; Koracin, Darko; Pavlidis, Ioannis; Feris, Rogerio; McGraw, Tim; Elendt, Mark; Kopper, Regis; Ragan, Eric; Ye, Zhao; Weber, Gunther H. (Hg.): Advances in visual computing: Proceedings: 11th International Symposium on Visual Computing (ISVC'15): Las Vegas, 14. - 16. Dezember: Heidelberg: Springer (Lecture notes in computer science; Image processing, computer vision, pattern recognition, and graphics), S. 733-744
DOI: https://doi.org/10.1007/978-3-319-27863-6_69 Abstract: Various software metrics can be derived from a software system to measure inherent quantitative properties such a system can have or not. The general problem with these metrics is the fact that many of them may exist with varying values making an exploration of the raw metric data a challenging task. As another data dimension we have to deal with the hierarchical organization of the software system since we are also interested in software metric correlations or anomalies on different hierarchy levels. In this paper we introduce a visualization concept which shows the hierarchical organization of the software system on the one hand, but also the list of software metrics attached to each hierarchy level on the other hand. This interactive technique exploits the strengths of the human visual system that allow fast pattern recognition to derive similar or different metric patterns in the software hierarchy. The provided visualization technique targets the rapid finding of insights and knowledge in the typically vast amounts of multivariate and hierarchical software metric data. We illustrate the usefulness of our approach in a case study investigating more than 70 software metrics in the Eclipse open source software project.
-
(2015) : The Aesthetics of Diagrams In: Braz, Jose; Kerren, Andreas; Linsen, Lars (Hg.): 6th International Conference on Information Visualization Theory and Applications: Proceedings: IVAPP: Berlin, 11. - 14. März: Setúbal: SciTePress, S. 262-267. Online verfügbar unter https://doi.org/10.5220/0005357502620267, zuletzt geprüft am 10.09.2021
Abstract: Diagrammatic representations are omnipresent and are used in various application domains. One of their major goal, in particular for information visualization, is to make data visual in a way that a spectator can easily understand the graphical encoding to finally derive insights from the data. As we see, there are various different ways to visually depict data by using visual features in various combinations. In this paper we come up with some thoughts about existing diagram styles, for which we first discuss the benefits and drawbacks of each of them focusing on aesthetics based on readability. Additionally, we describe some initial results on the aesthetics of diagrams which we recorded in a web-based experiment. In this, we asked participants to vote for one of two given diagrams of a given repertoire of 70 of them covering all examined aspects which focuses more on aesthetics in the sense of beauty, not readability. The major result of this experiment unhides a trend towards col ored, 3D, and radial diagrams which stands somewhat in contrast to readability user studies in information visualization oftentimes tending towards 2D and Cartesian diagrams for data exploration.
-
(2015) : Edge-stacked Timelines for Visualizing Dynamic Weighted Digraphs In: Braz, Jose; Kerren, Andreas; Linsen, Lars (Hg.): 6th International Conference on Information Visualization Theory and Applications: Proceedings: IVAPP: Berlin, 11. - 14. März: Setúbal: SciTePress, S. 93-100. Online verfügbar unter https://doi.org/10.5220/0005259200930100, zuletzt geprüft am 10.09.2021
Abstract: We investigate the problem of visually encoding time-varying weighted digraphs to provide an overview about dynamic graphs. Starting from a rough overview of dynamic relational data an analyst can subsequently explore the data in more detail to gain further insights. To reach this goal we first map the graph vertices in the graph sequence to a common horizontal axis. Edges between vertices are represented as stacked horizontal and color-coded links starting and ending at their corresponding start and end vertex positions. The direction of each edge is indicated by placing it either above or below the horizontal vertex line. We attach a vertically aligned timeline to each link to show the weight evolution for those links. The order of the vertices and stacked edges is important for the readability of the visualization. We support interactive reordering and sorting in the vertex, edge, and timeline representations. The usefulness of our edge-stacked timelines is illustrated in a case s tudy showing dynamic call graph data from software development.
-
(2015) : Visual Analysis of Eye Movements by Hierarchical Filter Wheels: Information Visualisation: Computer Graphics, Imaging and Visualisation. Biomedical Visualization, Visualisation on Built and Rural Environments & Geometric Modelling and Imaging: Proceedings: 19th International Conference on Information Visualisation (IV): Barcelona, 22. - 24. Juli: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 107-113. Online verfügbar unter https://doi.org/10.1109/iV.2015.29, zuletzt geprüft am 10.09.2021
Abstract: The visual exploration of spatio-temporal eye movement data is challenging, especially if we are interested in the movement patterns of a large number of study participants. For example, if popular visualization techniques like heat maps or gaze plots are used, we may lose the temporal information or get lost in visual clutter. To address these issues, we propose an approach for filtering saccadic eye movement data called hierarchical filter wheels, which employs a radial representation of saccade information. It supports the analysis of sequences of saccades by filtering them with respect to direction and length. The focus of our approach is a fast initial analysis of data from eye tracking studies without the need of defining areas of interest (AOIs) or other preprocessing of the data. The hierarchical filters are interactively generated on users' demand by creating a hierarchy of multiple filter wheels each filtering one element of the sequence. We use a bubble tree layout to represent the generated filter hierarchy. The node positions in our layout directly represent the spatial properties of the filter criteria allowing an intuitive incremental generation and understanding of filter hierarchies. We illustrate the approach by applying it to eye movement data formerly recorded in an eye tracking study investigating the readability of different node-link tree diagrams. We further demonstrate how the hierarchical filter wheels can be used in combination with gaze plots.
-
(2015) : Visualizing the Evolution of Module Workflows: Information Visualisation: Computer Graphics, Imaging and Visualisation. Biomedical Visualization, Visualisation on Built and Rural Environments & Geometric Modelling and Imaging: Proceedings: 19th International Conference on Information Visualisation (IV): Barcelona, 22. - 24. Juli: Piscataway, NJ: Institute of Electrical and Electronic Engineers (IEEE), S. 40-49. Online verfügbar unter https://doi.org/10.1109/iV.2015.19, zuletzt geprüft am 10.09.2021
Abstract: Module workflows are used to generate custom applications with modular software frameworks. They describe data flow between the modular components and their execution under certain parameter configurations. In many cases, module workflows are modeled in a graphical way by the user. To come up with the final result or to explore multiple solutions, they often undergo many iterations of adaptation. Furthermore, existing workflows may be reused for new applications. We visualize the evolution of module workflows with a focus-and-context approach and visualization techniques for time-dependent data. Our approach provides insight into user behavior and the characteristics of the underlying systems. As our examples show, this can help identify usability issues and indicate options to improve the effectiveness of the system. We demonstrate our approach for module workflows in Vis Trails, a modular visualization system that allows building custom visualizations by combining different modules for processing and visualizing data.
-
(2015): Eye Tracking in Computer-Based Visualization. In: Computing in Science & Engineering 17, S. 64-71. Online verfügbar unter https://doi.org/10.1109/MCSE.2015.93, zuletzt geprüft am 10.09.2021
Abstract: The authors describe the creation of a tridimensional fly-through animation across the largest map of galaxies to date. This project represented a challenge: creating a scientifically accurate representation of the galaxy distribution that was aesthetically pleasing. The animation shows almost half a million galaxies as the viewer travels through the vast intergalactic regions, giving a glimpse of the sheer size of the universe.