@article{sorger-2021-egonet, title = "Egocentric Network Exploration for Immersive Analytics", author = "Johannes Sorger and Alessio Arleo and Peter K\'{a}n and Wolfgang Knecht and Manuela Waldner", year = "2021", abstract = "To exploit the potential of immersive network analytics for engaging and effective exploration, we promote the metaphor of ``egocentrism'', where data depiction and interaction are adapted to the perspective of the user within a 3D network. Egocentrism has the potential to overcome some of the inherent downsides of virtual environments, e.g., visual clutter and cyber-sickness. To investigate the effect of this metaphor on immersive network exploration, we designed and evaluated interfaces of varying degrees of egocentrism. In a user study, we evaluated the effect of these interfaces on visual search tasks, efficiency of network traversal, spatial orientation, as well as cyber-sickness. Results show that a simple egocentric interface considerably improves visual search efficiency and navigation performance, yet does not decrease spatial orientation or increase cyber-sickness. A distorted occlusion-free view of the neighborhood only marginally improves the user's performance. We tie our findings together in an open online tool for egocentric network exploration, providing actionable insights on the benefits of the egocentric network exploration metaphor.", month = oct, journal = "Computer Graphics Forum", volume = "40", doi = "10.1111/cgf.14417", pages = "12", publisher = "John Wiley and Sons", pages = "241--252", keywords = "Computer Graphics and Computer-Aided Design", URL = "https://www.cg.tuwien.ac.at/research/publications/2021/sorger-2021-egonet/", } @inproceedings{sorger-2019-odn, title = "Immersive Analytics of Large Dynamic Networks via Overview and Detail Navigation", author = "Johannes Sorger and Manuela Waldner and Wolfgang Knecht and Alessio Arleo", year = "2019", abstract = "Analysis of large dynamic networks is a thriving research field, typically relying on 2D graph representations. The advent of affordable head mounted displays sparked new interest in the potential of 3D visualization for immersive network analytics. Nevertheless, most solutions do not scale well with the number of nodes and edges and rely on conventional fly- or walk-through navigation. In this paper, we present a novel approach for the exploration of large dynamic graphs in virtual reality that interweaves two navigation metaphors: overview exploration and immersive detail analysis. We thereby use the potential of state-of-the-art VR headsets, coupled with a web-based 3D rendering engine that supports heterogeneous input modalities to enable ad-hoc immersive network analytics. We validate our approach through a performance evaluation and a case study with experts analyzing medical data.", month = dec, organization = "IEEE", location = "San Diego, California, USA", event = "AIVR 2019", booktitle = "2nd International Conference on Artificial Intelligence & Virtual Reality", pages = "144--151", keywords = "Immersive Network Analytics, Web-Based Visualization, Dynamic Graph Visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/2019/sorger-2019-odn/", } @inproceedings{Arleo-2019-vis, title = "Sabrina: Modeling and Visualization of Economy Data with Incremental Domain Knowledge", author = "Alessio Arleo and Christos Tsigkanos and Chao Jia and Roger Leite and Ilir Murturi and Manfred Klaffenb\"{o}ck and Schahram Dustdar and Silvia Miksch and Michael Wimmer and Johannes Sorger", year = "2019", abstract = "Investment planning requires knowledge of the financial landscape on a large scale, both in terms of geo-spatial and industry sector distribution. There is plenty of data available, but it is scattered across heterogeneous sources (newspapers, open data, etc.), which makes it difficult for financial analysts to understand the big picture. In this paper, we present Sabrina, a financial data analysis and visualization approach that incorporates a pipeline for the generation of firm-to-firm financial transaction networks. The pipeline is capable of fusing the ground truth on individual firms in a region with (incremental) domain knowledge on general macroscopic aspects of the economy. Sabrina unites these heterogeneous data sources within a uniform visual interface that enables the visual analysis process. In a user study with three domain experts, we illustrate the usefulness of Sabrina, which eases their analysis process.", month = oct, location = "Vancouver, British Columbia, Canada", event = " IEEE Visualization Conference (VIS)", booktitle = "IEEE VIS 2019", keywords = "Visualization, Visual Analytics", URL = "https://www.cg.tuwien.ac.at/research/publications/2019/Arleo-2019-vis/", } @article{miao_tvcg_2018, title = "Multiscale Visualization and Scale-adaptive Modification of DNA Nanostructures", author = "Haichao Miao and Elisa De Llano and Johannes Sorger and Yasaman Ahmadi and Tadija Kekic and Tobias Isenberg and Eduard Gr\"{o}ller and Ivan Barisic and Ivan Viola", year = "2018", month = jan, journal = "IEEE Transactions on Visualization and Computer Graphics", volume = "24", number = "1", URL = "https://www.cg.tuwien.ac.at/research/publications/2018/miao_tvcg_2018/", } @phdthesis{sorger-2017-thesis, title = "Integration Strategies in the Visualization of Multifaceted Spatial Data", author = "Johannes Sorger", year = "2017", abstract = "Visualization designers have several visual channels at their disposal for encoding data into visual representations, e.g., position, size, shape, orientation, color, texture, brightness, as well as motion. The mapping of attributes to visual channels can be chosen by the designer. In theory, any data attribute can be represented by any of these visual channels or by a combination of multiple of these channels. In practice, the optimal mapping and the most suitable type of visualization strongly depend on the data as well as on the user's task. In the visualization of spatial data, the mapping of spatial attributes to visual channels is inherently given by the data. Multifaceted spatial data possesses a wide range of additional (non-spatial) attributes without a given mapping. The data's given spatial context is often important for successfully fulfilling a task. The design space in spatial data visualization can therefore be heavily constrained when trying to choose an optimal mapping for other attributes within the spatial context. To solve an exploration or presentation task in the domain of multifaceted spatial data, special strategies have to be employed in order to integrate the essential information from the various data facets in an appropriate representation form with the spatial context. This thesis explores visualization integration strategies for multifaceted spatial data. The first part of this thesis describes the design space of integration in terms of two aspects: visual and functional integration. Visual integration describes how representations of the different data facets can be visually composed within a spatial context. Functional integration, describes how events that have been triggered, for instance, through user interaction, can be coordinated across the various visually integrated representations. The second part of this thesis describes contributions to the field of visualization in the context of concrete integration applications for exploration and presentation scenarios. The first scenario addresses a set of challenges in the exploratory analysis of multifaceted spatial data in the scope of a decision making scenario in lighting design. The user's task is to find an optimal lighting solution among dozens or even hundreds of potential candidates. In the scope of a design study, the challenges in lighting design are addressed with LiteVis, a system that integrates representations of the simulation parameter space with representations of all relevant aspects of the simulation output. The integration of these heterogeneous aspects together with a novel ranking visualization are thereby the key to enabling an efficient exploration and comparison of lighting parametrizations. In presentation scenarios, the generation of insights often cannot rely on user interaction and therefore needs a different approach. The challenge is to generate visually appealing, yet information-rich representations for mainly passive observation. In this context, this thesis addresses two different challenges in the domain of molecular visualization. The first challenge concerns the conveying of relations between two different representations of a molecular data set, such as a virus. The relation is established via animated transitions - a temporal form of integration between two representations. The proposed solution features a novel technique for creating such transitions that are re-usable for different data sets, and can be combined in a modular fashion. Another challenge in presentation scenarios of multifaceted spatial data concerns the presentation of the transition between development states of molecular models, where the actual biochemical process of the transition is not exactly known or it is too complex to represent. A novel technique applies a continuous abstraction of both model representations to a level of detail at which the relationship between them can be accurately conveyed, in order to overcome a potential indication of false relationship information. Integration thereby brings the different abstraction levels and the different model states into relation with each other. The results of this thesis clearly demonstrate that integration is a versatile tool in overcoming key challenges in the visualization of multifaceted spatial data. ", month = sep, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/sorger-2017-thesis/", } @inproceedings{sorger_2017_metamorphers, title = "Metamorphers: Storytelling Templates For Illustrative Animated Transitions in Molecular Visualization", author = "Johannes Sorger and Peter Mindek and Peter Rautek and Eduard Gr\"{o}ller and Graham Johnson and Ivan Viola", year = "2017", abstract = "In molecular biology, illustrative animations are used to convey complex biological phenomena to broad audiences. However, such animations have to be manually authored in 3D modeling software, a time consuming task that has to be repeated from scratch for every new data set, and requires a high level of expertise in illustration, animation, and biology. We therefore propose metamorphers: a set of operations for defining animation states as well as the transitions to them in the form of re-usable story telling templates. The re-usability is two-fold. Firstly, due to their modular nature, metamorphers can be re-used in different combinations to create a wide range of animations. Secondly, due to their abstract nature, metamorphers can be re-used to re-create an intended animation for a wide range of compatible data sets. Metamorphers thereby mask the low level complexity of explicit animation specifications by exploiting the inherent properties of the molecular data, such as the position, size, and hierarchy level of a semantic data subset.", month = may, location = "Mikulov, Czech Republic", booktitle = "Proceedings of the Spring Conference on Computer Graphics 2017", pages = "27--36", keywords = "animated transitions, storytelling, molecular visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/sorger_2017_metamorphers/", } @misc{mindek-2017-virtualcell, title = "The Birth of a Virtual Cell", author = "Peter Mindek and Johannes Sorger and David Kou\v{r}il and Tobias Klein and Graham Johnson and Ivan Viola", year = "2017", abstract = "In our current research project, we are working on the interactive visualization of cellular data at multiple scales. The visual story telling contest motivated us to describe the process of bringing this complex volumetric data "to life". We scripted the visual story directly within the current build of our multi-scale visualization. The entire video is therefore rendered in real time. This enabled us to directly show the steps involved in the rendering of our final visualization based on the actual data and the actual algorithms that are applied. The various effects in the video are therefore parameter variables for existing multi-scale visualization functions that change over time. The final result of our visualization was inspired by a rendering of the reference 3D model that was created by a scientific illustrator. The challenge that we overcome in our visualization was to create a rendering of the original data at stable 30 frames per second that matches the offline rendered illustration in visual quality, which helps to clarify the complex 3D arrangements of the inner components of the cell.", month = apr, note = "submitted to the Pacific Vis 2017 Storytelling Contest", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/mindek-2017-virtualcell/", } @article{mindek-2017-marion, title = "Visualization Multi-Pipeline for Communicating Biology", author = "Peter Mindek and David Kou\v{r}il and Johannes Sorger and David Toloudis and Blair Lyons and Graham Johnson and Eduard Gr\"{o}ller and Ivan Viola", year = "2017", abstract = "We propose a system to facilitate biology communication by developing a pipeline to support the instructional visualization of heterogeneous biological data on heterogeneous user-devices. Discoveries and concepts in biology are typically summarized with illustrations assembled manually from the interpretation and application of heterogenous data. The creation of such illustrations is time consuming, which makes it incompatible with frequent updates to the measured data as new discoveries are made. Illustrations are typically non-interactive, and when an illustration is updated, it still has to reach the user. Our system is designed to overcome these three obstacles. It supports the integration of heterogeneous datasets, reflecting the knowledge that is gained from different data sources in biology. After pre-processing the datasets, the system transforms them into visual representations as inspired by scientific illustrations. As opposed to traditional scientific illustration these representations are generated in real-time - they are interactive. The code generating the visualizations can be embedded in various software environments. To demonstrate this, we implemented both a desktop application and a remote-rendering server in which the pipeline is embedded. The remote-rendering server supports multi-threaded rendering and it is able to handle multiple users simultaneously. This scalability to different hardware environments, including multi-GPU setups, makes our system useful for efficient public dissemination of biological discoveries. ", journal = "IEEE Transactions on Visualization and Computer Graphics", volume = "24", number = "1", keywords = "Biological visualization, remote rendering, public dissemination", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/mindek-2017-marion/", } @inproceedings{sorger-2016-fowardabstraction, title = "Illustrative Transitions in Molecular Visualization via Forward and Inverse Abstraction Transform", author = "Johannes Sorger and Peter Mindek and Tobias Klein and Graham Johnson and Ivan Viola", year = "2016", abstract = "A challenging problem in biology is the incompleteness of acquired information when visualizing biological phenomena. Structural biology generates detailed models of viruses or bacteria at different development stages, while the processes that relate one stage to another are often not clear. Similarly, the entire life cycle of a biological entity might be available as a quantitative model, while only one structural model is available. If the relation between two models is specified at a lower level of detail than the actual models themselves, the two models cannot be interpolated correctly. We propose a method that deals with the visualization of incomplete data information in the developmental or evolutionary states of biological mesoscale models, such as viruses or microorganisms. The central tool in our approach is visual abstraction. Instead of directly interpolating between two models that show different states of an organism, we gradually forward transform the models into a level of visual abstraction that matches the level of detail of the modeled relation between them. At this level, the models can be interpolated without conveying false information. After the interpolation to the new state, we apply the inverse transformation to the model’'s original level of abstraction. To show the flexibility of our approach, we demonstrate our method on the basis of molecular data, in particular data of the HIV virion and the mycoplasma bacterium.", month = sep, organization = "Eurographics", location = "Bergen", editor = "S. Bruckner, B. Preim, and A. Vilanova", booktitle = "Eurographics Workshop on Visual Computing for Biology and Medicine (VCBM)", pages = "21--30", keywords = "I.3.3 [Computer Graphics]: Picture/Image Generation-Display algorithms", URL = "https://www.cg.tuwien.ac.at/research/publications/2016/sorger-2016-fowardabstraction/", } @article{ortner-2016-tunnel, title = "Visual analytics and rendering for tunnel crack analysis", author = "Thomas Ortner and Johannes Sorger and Harald Piringer and Gerd Hesina and Eduard Gr\"{o}ller", year = "2016", abstract = "The visual analysis of surface cracks plays an essential role in tunnel maintenance when assessing the condition of a tunnel. To identify patterns of cracks, which endanger the structural integrity of its concrete surface, analysts need an integrated solution for visual analysis of geometric and multivariate data to decide if issuing a repair project is necessary. The primary contribution of this work is a design study, supporting tunnel crack analysis by tightly integrating geometric and attribute views to allow users a holistic visual analysis of geometric representations and multivariate attributes. Our secondary contribution is Visual Analytics and Rendering, a methodological approach which addresses challenges and recurring design questions in integrated systems. We evaluated the tunnel crack analysis solution in informal feedback sessions with experts from tunnel maintenance and surveying. We substantiated the derived methodology by providing guidelines and linking it to examples from the literature.", month = may, journal = "The Visual Computer", volume = "32", number = "6", pages = "859--869", keywords = "Integration of spatial and non-spatial data, Methodology, Visual analytics", URL = "https://www.cg.tuwien.ac.at/research/publications/2016/ortner-2016-tunnel/", } @article{ortner-2016-visaware, title = "Vis-a-ware: Integrating spatial and non-spatial visualization for visibility-aware urban planning", author = "Thomas Ortner and Johannes Sorger and Harald Steinlechner and Gerd Hesina and Harald Piringer and Eduard Gr\"{o}ller", year = "2016", abstract = "3D visibility analysis plays a key role in urban planning for assessing the visual impact of proposed buildings on the cityscape. A call for proposals typically yields around 30 candidate buildings that need to be evaluated with respect to selected viewpoints. Current visibility analysis methods are very time-consuming and limited to a small number of viewpoints. Further, analysts neither have measures to evaluate candidates quantitatively, nor to compare them efficiently. The primary contribution of this work is the design study of Vis-A-Ware, a visualization system to qualitatively and quantitatively evaluate, rank, and compare visibility data of candidate buildings with respect to a large number of viewpoints. Vis-A-Ware features a 3D spatial view of an urban scene and non-spatial views of data derived from visibility evaluations, which are tightly integrated by linked interaction. To enable a quantitative evaluation we developed four metrics in accordance with experts from urban planning. We illustrate the applicability of Vis-A-Ware on the basis of a use case scenario and present results from informal feedback sessions with domain experts from urban planning and development. This feedback suggests that Vis-A-Ware is a valuable tool for visibility analysis allowing analysts to answer complex questions more efficiently and objectively.", month = jan, journal = "Visualization and Computer Graphics, IEEE Transactions on", issn = "1077-2626 ", URL = "https://www.cg.tuwien.ac.at/research/publications/2016/ortner-2016-visaware/", } @article{sorger-2015-litevis, title = "LiteVis: Integrated Visualization for Simulation-Based Decision Support in Lighting Design", author = "Johannes Sorger and Thomas Ortner and Christian Luksch and Michael Schw\"{a}rzler and Eduard Gr\"{o}ller and Harald Piringer", year = "2016", abstract = "State-of-the-art lighting design is based on physically accurate lighting simulations of scenes such as offices. The simulation results support lighting designers in the creation of lighting configurations, which must meet contradicting customer objectives regarding quality and price while conforming to industry standards. However, current tools for lighting design impede rapid feedback cycles. On the one side, they decouple analysis and simulation specification. On the other side, they lack capabilities for a detailed comparison of multiple configurations. The primary contribution of this paper is a design study of LiteVis, a system for efficient decision support in lighting design. LiteVis tightly integrates global illumination-based lighting simulation, a spatial representation of the scene, and non-spatial visualizations of parameters and result indicators. This enables an efficient iterative cycle of simulation parametrization and analysis. Specifically, a novel visualization supports decision making by ranking simulated lighting configurations with regard to a weight-based prioritization of objectives that considers both spatial and non-spatial characteristics. In the spatial domain, novel concepts support a detailed comparison of illumination scenarios. We demonstrate LiteVis using a real-world use case and report qualitative feedback of lighting designers. This feedback indicates that LiteVis successfully supports lighting designers to achieve key tasks more efficiently and with greater certainty.", month = jan, journal = "Visualization and Computer Graphics, IEEE Transactions on", volume = "22", number = "1", issn = "1077-2626 ", pages = "290--299", keywords = "Integrating Spatial and Non-Spatial Data", URL = "https://www.cg.tuwien.ac.at/research/publications/2016/sorger-2015-litevis/", } @article{lemuzic-mindek-2016-viseq, title = "Visibility Equalizer: Cutaway Visualization of Mesoscopic Biological Models", author = "Mathieu Le Muzic and Peter Mindek and Johannes Sorger and Ludovic Autin and David Goodsell and Ivan Viola", year = "2016", abstract = "In scientific illustrations and visualization, cutaway views are often employed as an effective technique for occlusion management in densely packed scenes.We propose a novel method for authoring cutaway illustrations of mesoscopic biological models. In contrast to the existing cutaway algorithms, we take advantage of the specific nature of the biological models. These models consist of thousands of instances with a comparably smaller number of different types. Our method constitutes a two stage process. In the first step, clipping objects are placed in the scene, creating a cutaway visualization of the model. During this process, a hierarchical list of stacked bars inform the user about the instance visibility distribution of each individual molecular type in the scene. In the second step, the visibility of each molecular type is fine-tuned through these bars, which at this point act as interactive visibility equalizers. An evaluation of our technique with domain experts confirmed that our equalizer-based approach for visibility specification is valuable and effective for both, scientific and educational purposes.", journal = "Computer Graphics Forum", volume = "35", number = "3", keywords = "molecular visualization, visibility, occlusion", URL = "https://www.cg.tuwien.ac.at/research/publications/2016/lemuzic-mindek-2016-viseq/", } @inproceedings{sorger-2015-taxintec, title = "A Taxonomy of Integration Techniques for Spatial and Non-Spatial Visualizations", author = "Johannes Sorger and Thomas Ortner and Harald Piringer and Gerd Hesina and Eduard Gr\"{o}ller", year = "2015", abstract = "Research on visual data representations is traditionally classified into methods assuming an inherent mapping from data values to spatial coordinates (scientific visualization and real-time rendering) and methods for abstract data lacking explicit spatial references (information visualization). In practice, however, many applications need to analyze data comprising abstract and spatial information, thereby spanning both visualization domains. Traditional classification schemes do not support a formal description of these integrated systems. The contribution of this paper is a taxonomy that describes a holistic design space for integrating components of spatial and abstract visualizations. We structure a visualization into three components: Data, Visual, and Navigation. These components can be linked to build integrated visualizations. Our taxonomy provides an alternative view on the field of visualization in a time where the border between scientific and information visualization becomes blurred.", month = oct, series = "Springer Lecture Notes in Computer Science (LNCS) series", publisher = "The Eurographics Association", location = "Aachen, Germany", issn = "0302-9743", editor = "David Bommes and Tobias Ritschel and Thomas Schultz", booktitle = "20th International Symposium on Vision, Modeling and Visualization (VMV 2015)", URL = "https://www.cg.tuwien.ac.at/research/publications/2015/sorger-2015-taxintec/", } @inproceedings{sorger-2013-neuromap, title = "neuroMAP - Interactive Graph-Visualization of the Fruit Fly's Neural Circuit", author = "Johannes Sorger and Katja B\"{u}hler and Florian Schulze and Tianxiao Liu and Barry Dickson", year = "2013", abstract = "Neuroscientists study the function of neural circuits in the brain of the common fruit fly Drosophila melanogaster to discover how complex behavior is generated. To establish models of neural information processing, knowledge about potential connections between individual neurons is required. Connections can occur when the arborizations of two neurons overlap. Judging connectivity by analyzing overlaps using traditional volumetric visualization is difficult since the examined objects occlude each other. A more abstract form of representation is therefore desirable. In collaboration with a group of neuroscientists, we designed and implemented neuroMap, an interactive two-dimensional graph that renders the brain and its interconnections in the form of a circuit-style wiring diagram. neuroMap provides a clearly structured overview of all possible connections between neurons and offers means for interactive exploration of the underlying neuronal database. In this paper, we discuss the design decisions that formed neuroMap and evaluate its application in discussions with the scientists.", month = oct, publisher = "IEEE", location = "Atlanta", booktitle = "Biological Data Visualization (BioVis), 2013 IEEE Symposium on ", pages = "73--80", URL = "https://www.cg.tuwien.ac.at/research/publications/2013/sorger-2013-neuromap/", } @mastersthesis{Sorger_2013_nMI, title = "neuroMap - Interactive Graph-Visualization of the Fruit Fly’s Neural Circuit", author = "Johannes Sorger", year = "2013", abstract = "Neuroscientists study the function of neural circuits in the brain of the common fruit fly Drosophila Melanogaster to discover how complex behavior is generated. Through a combination of molecular-genetic techniques and confocal microscopy the scientists are able to highlight single neurons and produce three-dimensional images of the fly’s brain. Neurons are segmented, annotated, and compiled into a digital atlas. Brain atlases offer tools for exploring and analyzing their underlying data. To establish models of neural information processing, knowledge about possible connections between individual neurons is necessary. Connections can occur when arborizations (the terminal branchings of nerve fibers) of two neurons are overlapping. However, analyzing overlapping objects using traditional volumetric visualization is difficult since the examined objects occlude each other. A more abstract form of representation is therefore required. The work in this thesis was motivated by a manually constructed two-dimensional circuit diagram of potential neuronal connections that represents a novel way of visualizing neural connectivity data. Through abstracting the complex volumetric data, the diagram offers an intuitive and clear overview of potential connectivity. In collaboration with a group of neuroscientists neuroMap was designed and implemented in an attempt to deliver the visual features and encoded information of this circuit diagram in an automatically generated interactive graph, with the goal of facilitating hypothesis formation and exploration of neural connectivity. In this thesis the visual and interaction design decisions that went into neuroMap are presented, as well as the result of evaluative discussions that shows that the integration of this novel type of visualization into the existing datamining infrastructure of our clients is indeed beneficial to their research.", month = jan, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2013/Sorger_2013_nMI/", }