@ARTICLE {LawonnSmit-2017-Survey, author = "Lawonn, K. and Smit, N.N. and B{\"u}hler, K. and Preim, B.", title = "A Survey on Multimodal Medical Data Visualization", journal = "Computer Graphics Forum", year = "2017", abstract = "Multi-modal data of the complex human anatomy contain a wealth of information. To visualize and explore such data, techniques for emphasizing important structures and controlling visibility are essential. Such fused overview visualizations guide physicians to suspicious regions to be analysed in detail, e.g. with slice-based viewing. We give an overview of state of the art in multi-modal medical data visualization techniques. Multi-modal medical data consist of multiple scans of the same subject using various acquisition methods, often combining multiple complimentary types of information. Three-dimensional visualization techniques for multi-modal medical data can be used in diagnosis, treatment planning, doctor–patient communication as well as interdisciplinary communication. Over the years, multiple techniques have been developed in order to cope with the various associated challenges and present the relevant information from multiple sources in an insightful way. We present an overview of these techniques and analyse the specific challenges that arise in multi-modal data visualization and how recent works aimed to solve these, often using smart visibility techniques. We provide a taxonomy of these multi-modal visualization applications based on the modalities used and the visualization techniques employed. Additionally, we identify unsolved problems as potential future research directions.", pdf = "pdfs/LawonnSmit-2017-MULTI.pdf", images = "images/LawonnSmit-2017-MULTI.jpg", thumbnails = "images/LawonnSmit-2017-MULTI-TN.png", note = "CGF Early View", issn = "1467-8659", url = "http://dx.doi.org/10.1111/cgf.13306", doi = "10.1111/cgf.13306", keywords = "medical imaging, visualization, scientific visualization, visualization, volume visualization, visualization, Medical Imaging [Visualization], Scientific Visualization [Visualization], Volume Visualization [Visualization], Multimodal Medical Data" } @ARTICLE {Turkay2017VIS, author = "C. Turkay and E. Kaya and S. Balcisoy and H. Hauser", title = "Designing Progressive and Interactive Analytics Processes for High-Dimensional Data Analysis", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2017", volume = "PP", number = "99", pages = "1-1", month = "jan", abstract = "In interactive data analysis processes, the dialogue between the human and the computer is the enabling mechanism that can lead to actionable observations about the phenomena being investigated. It is of paramount importance that this dialogue is not interrupted by slow computational mechanisms that do not consider any known temporal human-computer interaction characteristics that prioritize the perceptual and cognitive capabilities of the users. In cases where the analysis involves an integrated computational method, for instance to reduce the dimensionality of the data or to perform clustering, such non-optimal processes are often likely. To remedy this, progressive computations, where results are iteratively improved, are getting increasing interest in visual analytics. In this paper, we present techniques and design considerations to incorporate progressive methods within interactive analysis processes that involve high-dimensional data. We define methodologies to facilitate processes that adhere to the perceptual characteristics of users and describe how online algorithms can be incorporated within these. A set of design recommendations and according methods to support analysts in accomplishing high-dimensional data analysis tasks are then presented. Our arguments and decisions here are informed by observations gathered over a series of analysis sessions with analysts from finance. We document observations and recommendations from this study and present evidence on how our approach contribute to the efficiency and productivity of interactive visual analysis sessions involving high-dimensional data.", pdf = "pdfs/2016-11-04--Turkay-2017-VIS.pdf", images = "images/Turkay-2017-VIS.png", thumbnails = "images/Turkay-2017-VIS.png", doi = "10.1109/TVCG.2016.2598470", issn = "1077-2626" } @ARTICLE {Stoppel2017VPI, author = "Sergej Stoppel and Stefan Bruckner", title = "Volvelle: Printable Interactive Volume Visualization", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2017", volume = "23", number = "1", month = "jan", abstract = "Interaction is an indispensable aspect of data visualization. The presentation of volumetric data, in particular, often significantly benefits from interactive manipulation of parameters such as transfer functions, rendering styles, or clipping planes. However, when we want to create hardcopies of such visualizations, this essential aspect is lost. In this paper, we present a novel approach for creating hardcopies of volume visualizations which preserves a certain degree of interactivity. We present a method for automatically generating Volvelles, printable tangible wheel charts that can be manipulated to explore different parameter settings. Our interactive system allows the flexible mapping of arbitrary visualization parameters and supports advanced features such as linked views. The resulting designs can be easily reproduced using a standard printer and assembled within a few minutes.", images = "images/Stoppel-2017-VPI.jpg", thumbnails = "images/Stoppel-2017-VPI.png", note = "Accepted for publication, to be presented at IEEE SciVis 2016", doi = "10.1109/TVCG.2016.2599211" } @ARTICLE {Smit2017PAS, author = "Noeska Smit and Kai Lawonn and Annelot Kraima and Marco DeRuiter and Hessam Sokooti and Stefan Bruckner and Elmar Eisemann and Anna Vilanova", title = "PelVis: Atlas-based Surgical Planning for Oncological Pelvic Surgery", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2017", volume = "23", number = "1", month = "jan", abstract = "Due to the intricate relationship between the pelvic organs and vital structures, such as vessels and nerves, pelvic anatomy is often considered to be complex to comprehend. In oncological pelvic surgery, a trade-off has to be made between complete tumor resection and preserving function by preventing damage to the nerves. Damage to the autonomic nerves causes undesirable post-operative side-effects such as fecal and urinal incontinence, as well as sexual dysfunction in up to 80 percent of the cases. Since these autonomic nerves are not visible in pre-operative MRI scans or during surgery, avoiding nerve damage during such a surgical procedure becomes challenging. In this work, we present visualization methods to represent context, target, and risk structures for surgical planning. We employ distance-based and occlusion management techniques in an atlas-based surgical planning tool for oncological pelvic surgery. Patient-specific pre-operative MRI scans are registered to an atlas model that includes nerve information. Through several interactive linked views, the spatial relationships and distances between the organs, tumor and risk zones are visualized to improve understanding, while avoiding occlusion. In this way, the surgeon can examine surgically relevant structures and plan the procedure before going into the operating theater, thus raising awareness of the autonomic nerve zone regions and potentially reducing post-operative complications. Furthermore, we present the results of a domain expert evaluation with surgical oncologists that demonstrates the advantages of our approach.", pdf = "pdfs/Smit-2016-PAS.pdf", images = "images/Smit-2017-PAS.jpg", thumbnails = "images/Smit-2017-PAS.png", youtube = "https://www.youtube.com/watch?v=vHp05I5-hp8", note = "To Appear. Presented at IEEE SciVis 2016", event = "IEEE SciVis 2016", keywords = "atlas, surgical planning, medical visualization", location = "Baltimore, USA" } @ARTICLE {Kolesar2017FCP, author = "I. Kolesar and S. Bruckner and I. Viola and H. Hauser", title = "A Fractional Cartesian Composition Model for Semi-spatial Comparative Visualization Design", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2017", volume = "23", number = "1", pages = "1-1", month = "Jan", abstract = "The study of spatial data ensembles leads to substantial visualization challenges in a variety of applications. In this paper, we present a model for comparative visualization that supports the design of according ensemble visualization solutions by partial automation. We focus on applications, where the user is interested in preserving selected spatial data characteristics of the data as much as possibleeven when many ensemble members should be jointly studied using comparative visualization. In our model, we separate the design challenge into a minimal set of user-specified parameters and an optimization component for the automatic configuration of the remaining design variables. We provide an illustrated formal description of our model and exemplify our approach in the context of several application examples from different domains in order to demonstrate its generality within the class of comparative visualization problems for spatial data ensembles.", images = "images/Kolesar-2017-FCC.jpg", thumbnails = "images/Kolesar-2017-FCC.png", note = "Accepted for publication, presented at IEEE SciVis 2016", publisher = "IEEE", keywords = "Computational modeling;Data models;Data visualization;Encoding;Spatial databases;Three-dimensional displays;Visualization;Design Methodologies;Integrating Spatial and Non-Spatial Data Visualization;Visualization Models", doi = "10.1109/TVCG.2016.2598870", issn = "1077-2626", project = "physioillustration" } @ARTICLE {Lind2017CCR, author = "Andreas Johnsen Lind and Stefan Bruckner", title = "Comparing Cross-Sections and 3D Renderings for Surface Matching Tasks using Physical Ground Truths", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2017", volume = "23", number = "1", month = "jan", abstract = "Within the visualization community there are some well-known techniques for visualizing 3D spatial data and some general assumptions about how perception affects the performance of these techniques in practice. However, there is a lack of empirical research backing up the possible performance differences among the basic techniques for general tasks. One such assumption is that 3D renderings are better for obtaining an overview, whereas cross sectional visualizations such as the commonly used Multi- Planar Reformation (MPR) are better for supporting detailed analysis tasks. In the present study we investigated this common assumption by examining the difference in performance between MPR and 3D rendering for correctly identifying a known surface. We also examined whether prior experience working with image data affects the participants performance, and whether there was any difference between interactive or static versions of the visualizations. Answering this question is important because it can be used as part of a scientific and empirical basis for determining when to use which of the two techniques. An advantage of the present study compared to other studies is that several factors were taken into account to compare the two techniques. The problem was examined through an experiment with 45 participants, where physical objects were used as the known surface (ground truth). Our findings showed that: 1. The 3D renderings largely outperformed the cross sections; 2. Interactive visualizations were partially more effective than static visualizations; and 3. The high experience group did not generally outperform the low experience group.", images = "images/Lind-2017-CCR.jpg", thumbnails = "images/Lind-2017-CCR.png", note = "Accepted for publication, to be presented at IEEE SciVis 2016", event = "IEEE SciVis 2016", doi = "10.1109/TVCG.2016.2598602", keywords = "human-computer interaction, quantitative evaluation, volume visualization", location = "Baltimore, USA" } @ARTICLE {Kolesar-2017-FCC, author = "Ivan Kolesar and Stefan Bruckner and Ivan Viola and Helwig Hauser", title = "A Fractional Cartesian Composition Model for Semi-spatial Comparative Visualization Design", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2017", volume = "23", number = "1", pages = "851--860", month = "jan", abstract = "The study of spatial data ensembles leads to substantial visualization challenges in a variety of applications. In this paper, we present a model for comparative visualization that supports the design of according ensemble visualization solutions by partial automation. We focus on applications, where the user is interested in preserving selected spatial data characteristics of the data as much as possibleóeven when many ensemble members should be jointly studied using comparative visualization. In our model, we separate the design challenge into a minimal set of user-specified parameters and an optimization component for the automatic configuration of the remaining design variables. We provide an illustrated formal description of our model and exemplify our approach in the context of several application examples from different domains in order to demonstrate its generality within the class of comparative visualization problems for spatial data ensembles.", images = "images/Kolesar-2017-FCC.jpg", thumbnails = "images/Kolesar-2017-FCC.png", event = "IEEE SciVis 2016", doi = "10.1109/TVCG.2016.2598870", keywords = "visualization models, integrating spatial and non-spatial data visualization, design methodologies", location = "Baltimore, USA" } @ARTICLE {Solteszova-2016-OFS, author = "Veronika \v{S}olt{\'e}szov{\'a} and {\AA}smund Birkeland and Sergej Stoppel and Ivan Viola and Stefan Bruckner", title = "Output-Sensitive Filtering of Streaming Volume Data", journal = "Computer Graphics Forum", year = "2016", abstract = "Real-time volume data acquisition poses substantial challenges for the traditional visualization pipeline where data enhancement is typically seen as a pre-processing step. In the case of 4D ultrasound data, for instance, costly processing operations to reduce noise and to remove artifacts need to be executed for every frame. To enable the use of high quality filtering operations in such scenarios, we propose an output-sensitive approach to the visualization of streaming volume data. Our method evaluates the potential contribution of all voxels to the final image, allowing us to skip expensive processing operations that have little or no effect on the visualization. As filtering operations modify the data values which may affect the visibility, our main contribution is a fast scheme to predict their maximum effect on the final image. Our approach prioritizes filtering of voxels with high contribution to the final visualization based on a maximal permissible error per pixel. With zero permissible error, the optimized filtering will yield a result identical to filtering of the entire volume. We provide a thorough technical evaluation of the approach and demonstrate it on several typical scenarios that require on-the-fly processing.", images = "images/Solteszova-2016-OFS.jpg", thumbnails = "images/Solteszova-2016-OFS.png", note = "Accepted and published online, to be inlcuded in an upcoming issue", doi = "10.1111/cgf.12799", keywords = "output-sensitive processing, volume data, filtering" } @ARTICLE {byska2016animoaminominer, author = "Jan Byska and Mathieu Le Muzic and Meister Eduard Gr{\”o}ller and Ivan Viola and Barbora Kozlikova", title = "AnimoAminoMiner: Exploration of Protein Tunnels and their Properties in Molecular Dynamics", journal = "Visualization and Computer Graphics, IEEE Transactions on", year = "2016", volume = "22", number = "1", pages = "747--756", abstract = "In this paper we propose a novel method for the interactive exploration of protein tunnels. The basic principle of our approach is that we entirely abstract from the 3D/4D space the simulated phenomenon is embedded in. A complex 3D structure and its curvature information is represented only by a straightened tunnel centerline and its width profile. This representation focuses on a key aspect of the studied geometry and frees up graphical estate to key chemical and physical properties represented by surroundingamino acids. The method shows the detailed tunnel profile and its temporal aggregation. The profile is interactively linked with a visual overview of all amino acids which are lining the tunnel over time. In this overview, each amino acid is represented by a set of colored lines depicting the spatial and temporal impact of the amino acid on the corresponding tunnel. This representation clearly shows the importance of amino acids with respect to selected criteria. It helps the biochemists to select the candidate amino acids for mutation which changes the protein function in a desired way. The AnimoAminoMiner was designed in close cooperation with domain experts. Its usefulness is documented by their feedback and a case study, which are included.", pdf = "pdfs/2016-Byska-AnimoAminoMiner.pdf", images = "images/IvanViola2016.png", thumbnails = "images/IvanViola2016.png", publisher = "IEEE" } @ARTICLE {Michael2016Visual, author = "Michael Krone and Barbora Kozlikova and Norbert Lindow and Marc Baaden and Daniel Baum, and Julius Parulek and Hans-Christian Hege and Ivan Viola", title = "Visual Analysis of Biomolecular Cavities: State of the Art", journal = "Computer Graphics Forum", year = "2016", abstract = "In this report we review and structure the branch of molecular visualization that is concerned with the visual analysis of cavities in macromolecular protein structures. First the necessary background, the domain terminology, and the goals of analytical reasoning are introduced. Based on a comprehensive collection of relevant research works, we present a novel classification for cavity detection approaches and structure them into four distinct classes: grid-based, Voronoi-based, surface-based, and probe-based methods. The subclasses are then formed by their combinations. We match these approaches with corresponding visualization technologies starting with direct 3D visualization, followed with non-spatial visualization techniques that for example abstract the interactions between structures into a relational graph, straighten the cavity of interest to see its profile in one view, or aggregate the time sequence into a single contour plot. We also discuss the current state of methods for the visual analysis of cavities in dynamic data such as molecular dynamics simulations. Finally, we give an overview of the most common tools that are actively developed and used in the structural biology and biochemistry research. Our report is concluded by an outlook on future challenges in the field.", images = "images/STARcavities2016.png", thumbnails = "images/STARcavities2016.png", publisher = "The Eurographics Association and John Wiley \& Sons Ltd.", issn = "1467-8659", doi = "10.1111/cgf.12928", project = "physioillustration" } @INPROCEEDINGS {lichtenberg2016, author = "Nils Lichtenberg and Noeska Smit and Christian Hansen and Kai Lawonn", title = "Sline: Seamless Line Illustration for Interactive Biomedical Visualization", proceedings = "EG Workshop on Visual Computing for Biology and Medicine", year = "2016", month = "sep", abstract = "In medical visualization of surface information, problems often arise when visualizing several overlapping structures simultaneously. There is a trade-off between visualizing multiple structures in a detailed way and limiting visual clutter, in order to allow users to focus on the main structures. Illustrative visualization techniques can help alleviate these problems by defining a level of abstraction per structure. However, clinical uptake of these advanced visualization techniques so far has been limited due to the complex parameter settings required. To bring advanced medical visualization closer to clinical application, we propose a novel illustrative technique that offers a seamless transition between various levels of abstraction and detail. Using a single comprehensive parameter, users are able to quickly define a visual representation per structure that fits the visualization requirements for focus and context structures. This technique can be applied to any biomedical context in which multiple surfaces are routinely visualized, such as neurosurgery, radiotherapy planning or drug design. Additionally, we introduce a novel hatching technique, that runs in real-time and does not require texture coordinates. An informal evaluation with experts from different biomedical domains reveals that our technique allows users to design focus-and-context visualizations in a fast and intuitive manner.", pdf = "pdfs/Lichtenberg-2016-SLINE.pdf", images = "images/Smit-2016-SLINE.PNG", thumbnails = "images/Smit-2016-SLINE-tn.jpg", youtube = "https://www.youtube.com/watch?v=7U8z5VsqyQE" } @MISC {Stoppel2015ConfReport, author = "Sergej Stoppel", title = "Conference Report IEEE VIS 2014", month = "January", year = "2016", abstract = "Conference report about the IEEE VIS 2014 in Paris.", images = "images/Shneiderman_Gerson_Pushups.PNG", thumbnails = "images/Shneiderman_Gerson_Pushups.PNG", url = "http://www.norsigd.no/norsigd_info/nsi-1-15.pdf" } @MISC {Hauser2015Austria, author = "Helwig Hauser", title = "Integrating Spatial \& Non-spatial Data in Visualization", howpublished = "Invited talk", month = "October", year = "2015", abstract = "New opportunities in data science, such as the consideration of cohort study data, require new approaches to the appropriate design of an effective visualization. We need to capitalize on successful solutions from previous research, of course, but we should also explore new strategies that challenge our already established mindset in visualization. In this talk, I address the specific challenge of integrating spatial and non-spatial data in visualization, in particular, when the spatial aspect of the data is of great importance to the user---this could relate to the morphological information in a 3D medical scan or the geometrical aspects of flow features in a CFD simulation. In data visualizaiton, the actual mapping step---from data to a visual form---is certainly crucial and we should strive to optimally exploit the great opportunities that we have in designing this step. In data-intensive sciences, the study objects of interest are increasingly often represented by extensive and rich datasets (aka. big data)---while traditionally the focus of visualization was on individual, static datasets, we now face dynamic data, representing entire ensembles of study entities, etc. Visualization gets a lot harder, when facing such new \"big data\" challenges---both on the designer sider as well as also on the user side. At the same time, however, also the potential for impact is increasing, which amounts to a fantastic motivation for new basic research in visualization.", pdf = "pdfs/2015-10-14--HHauser--InvTalk--print--2up.pdf", images = "images/ThumbPicHHAustria2015.png", thumbnails = "images/ThumbPicHHAustria2015.png", location = "Vienna, Austria" } @MISC {Hauser2015IRIS, author = "Helwig Hauser", title = "Medical Visualization Research at the VisGroup @ UiB.no/ii", howpublished = "Invited talk at IRIS", month = "November", year = "2015", abstract = "Established about eight years ago, the Visualization Research Group is the youngest of six research groups at the Department of Informatics, UiB, focusing on application-oriented basic research in visualization. Medicine and related disciplines (such as biomedicine, biology, etc.) stand for a growing number of grand visualization challenges and the vivid interdisciplinary MedViz network in Bergen gives ample opportunities for internationally recognized visualization research. In this talk, an overview of the visualization research group [1] is given, together with a short review of selected research projects in medical visualization.", pdf = "pdfs/2015-11-25--PresAtIRIS--print2up.pdf", images = "images/ThumbNailIRIS.jpg", thumbnails = "images/ThumbNailIRIS.jpg", day = "25", location = "Bergen, Norway" } @ARTICLE {Diehl2015VAS, author = "Alexandra Diehl and Leandro Pelorosso and Claudio Delrieux and Celeste Saulo and Juan Ruiz and Meister Eduard Gr{\"o}ller and Stefan Bruckner", title = "Visual Analysis of Spatio-Temporal Data: Applications in Weather Forecasting", journal = "Computer Graphics Forum", year = "2015", volume = "34", number = "3", pages = "381--390", month = "may", abstract = "Weather conditions affect multiple aspects of human life such as economy, safety, security, and social activities. For this reason, weather forecast plays a major role in society. Currently weather forecasts are based on Numerical Weather Prediction (NWP) models that generate a representation of the atmospheric flow. Interactive visualization of geo-spatial data has been widely used in order to facilitate the analysis of NWP models. This paper presents a visualization system for the analysis of spatio-temporal patterns in short-term weather forecasts. For this purpose, we provide an interactive visualization interface that guides users from simple visual overviews to more advanced visualization techniques. Our solution presents multiple views that include a timeline with geo-referenced maps, an integrated webmap view, a forecast operation tool, a curve-pattern selector, spatial filters, and a linked meteogram. Two key contributions of this work are the timeline with geo-referenced maps and the curve-pattern selector. The latter provides novel functionality that allows users to specify and search for meaningful patterns in the data. The visual interface of our solution allows users to detect both possible weather trends and errors in the weather forecast model.We illustrate the usage of our solution with a series of case studies that were designed and validated in collaboration with domain experts.", images = "images/Diehl-2015-VAS.jpg", thumbnails = "images/Diehl-2015-VAS.jpg", doi = "10.1111/cgf.12650", event = "EuroVis 2015", keywords = "weather forecasting, visual analysis, spatiotemporal data", location = "Cagliari, Italy", owner = "bruckner" } @MISC {Hauser2015SUBSEA, author = "Helwig Hauser", title = "Big Data - visualization and visual analytics", howpublished = "Invited talk at the NCE Subsea Forum", month = "March", year = "2015", pdf = "pdfs/2015-03-19--NCE--BigDataVA--print2up.pdf", images = "images/ThumbnailBigData.jpg", thumbnails = "images/ThumbnailBigData.jpg", day = "19", location = "Bergen, Norway" } @ARTICLE {Brambilla15Expressive, author = "Andrea Brambilla and Helwig Hauser", title = "Expressive Seeding of Multiple Stream Surfaces for Interactive Flow Exploration", journal = "Computers \& Graphics", year = "2015", volume = "47", pages = "123--134", abstract = "Integral surfaces, such as stream and path surfaces, are highly effective in the context of the exploration and the analysis of the long-term behavior of three-dimensional flows. However, specifying the seeding curves that lead to an expressive set of integral surfaces is a challenging and cumbersome task. In this paper, we propose an algorithm for automatically seeding multiple stream surfaces around a user-specified location of interest. The process is guided by a streamline similarity measure. Within the resulting integral surfaces, adjacent streamlines are as similar as possible to each other. In addition, we aim at conveying different aspects of the flow behavior with each surface. This is achieved by maximizing the dissimilarity between streamlines from different stream surfaces. The capabilities of our technique are demonstrated on a number of application cases. We provide a qualitative comparison with two state-of-the-art approaches. We report from our detailed exchange with a domain expert concerning the expressiveness and usefulness of our approach. A thorough analysis of the few parameters involved is provided. ", images = "images/Brambilla15Expressive01.png, images/Brambilla15Expressive02.png", thumbnails = "images/Brambilla15Expressive01_thumb.png, images/Brambilla15Expressive02_thumb.png", publisher = "Elsevier", doi = "http://dx.doi.org/10.1016/j.cag.2015.01.002", url = "http://www.sciencedirect.com/science/article/pii/S0097849315000035", keywords = "Flow visualization; Stream surface selection; Visibility management" } @ARTICLE {CGF:CGF12612, author = "Byška, J. and Jurčík, A. and Gröller, M. E. and Viola, I. and Kozlíková, B.", title = "MoleCollar and Tunnel Heat Map Visualizations for Conveying Spatio-Temporo-Chemical Properties Across and Along Protein Voids", journal = "Computer Graphics Forum", year = "2015", volume = "34", number = "3", pages = "1--10", abstract = "Studying the characteristics of proteins and their inner void space, including their geometry,physico-chemical properties and dynamics are instrumental for evaluating the reactivity of theprotein with other small molecules. The analysis of long simulations of molecular dynamics produces a large number of voids which have to be further explored and evaluated. In this paper we propose three new methods: two of them convey important properties along the long axis of a selected void during molecular dynamics and one provides a comprehensive picture across the void. The first two proposed methods use a specific heat map to present two types of information: an overview of all detected tunnels in the dynamics and their bottleneck width andstability over time, and an overview of a specific tunnel in the dynamics showing the bottleneck position and changes of the tunnel length over time. These methods help to select asmall subset of tunnels, which are explored individually and in detail. For this stage we propose the third method, which shows in one static image the temporal evolvement of the shapeof the most critical tunnel part, i.e., its bottleneck. This view is enriched with abstractdepictions of different physicochemical properties of the amino acids surrounding the bottleneck. The usefulness of our newly proposed methods is demonstrated on a case study andthe feedback from the domain experts is included. The biochemists confirmed that our novel methods help to convey the information about the appearance and properties of tunnels in a very intuitive and comprehensible manner.", images = "images/cgf12612-fig-0001.png", thumbnails = "images/cgf12612-fig-0001.png", issn = "1467-8659", url = "http://dx.doi.org/10.1111/cgf.12612", doi = "10.1111/cgf.12612", keywords = "Categories and Subject Descriptors (according to ACM CCS), I.3.6 [Computer Graphics]: Picture/Image Generation—Line and curve generation" } @ARTICLE {Karimov2015GVE, author = "Alexey Karimov and Gabriel Mistelbauer and Thomas Auzinger and Stefan Bruckner", title = "Guided Volume Editing based on Histogram Dissimilarity", journal = "Computer Graphics Forum", year = "2015", volume = "34", number = "3", pages = "91--100", month = "may", abstract = "Segmentation of volumetric data is an important part of many analysis pipelines, but frequently requires manual inspection and correction. While plenty of volume editing techniques exist, it remains cumbersome and error-prone for the user to find and select appropriate regions for editing. We propose an approach to improve volume editing by detecting potential segmentation defects while considering the underlying structure of the object of interest. Our method is based on a novel histogram dissimilarity measure between individual regions, derived from structural information extracted from the initial segmentation. Based on this information, our interactive system guides the user towards potential defects, provides integrated tools for their inspection, and automatically generates suggestions for their resolution. We demonstrate that our approach can reduce interaction effort and supports the user in a comprehensive investigation for high-quality segmentations.", images = "images/Karimov-2015-GVE.png", thumbnails = "images/Karimov-2015-GVE.png", doi = "10.1111/cgf.12621", event = "EuroVis 2015", keywords = "medical visualization, segmentation, volume editing, interaction", location = "Cagliari, Italy", owner = "bruckner", timestamp = "2015.06.08", url = "http://www.cg.tuwien.ac.at/research/publications/2015/karimov-2015-HD/" } @ARTICLE {Angelelli2015PQA, author = "Paolo Angelelli and Stefan Bruckner", title = "Performance and Quality Analysis of Convolution-Based Volume Illumination", journal = "Journal of WSCG", year = "2015", volume = "23", number = "2", pages = "131--138", month = "jun", abstract = "Convolution-based techniques for volume rendering are among the fastest in the on-the-fly volumetric illumination category. Such methods, however, are still considerably slower than conventional local illumination techniques. In this paper we describe how to adapt two commonly used strategies for reducing aliasing artifacts, namely pre-integration and supersampling, to such techniques. These strategies can help reduce the sampling rate of the lighting information (thus the number of convolutions), bringing considerable performance benefits. We performance improvements. We also analyze the (negligible) differences they introduce when comparing their output to the reference method. These strategies can be highly beneficial in setups where direct volume rendering of continuously streaming data is desired and continuous recomputation of full lighting information is too expensive, or where memory constraints make it preferable not to keep additional precomputed volumetric data in memory. In such situations these strategies make single pass, convolution-based volumetric illumination models viable for a broader range of applications, and this paper provides practical guidelines for using and tuning such strategies to specific use cases.", images = "images/Angelelli-2015-PQA.png", thumbnails = "images/Angelelli-2015-PQA.png", keywords = "volume rendering, global illumination, scientific visualization, medical visualization" } @MISC {Hauser2015VIS, author = "Helwig Hauser", title = "From Anatomy to Physiology in Medical Visualization", howpublished = "Tutorial talk at IEEE VIS 2015", month = "October", year = "2015", abstract = "Generally, medical visualization assists the diagnosis of diseases as well as the treatment of patients. Capturing the patients anatomy, which to a large degree is in the focus of traditional MedViz, certainly is one important key to the success of medical visualization. At least equally important, if not even more, is the consideration of physiology, entailing the complex of function (or malfunction) of the patient. Modern imaging modalities extend beyond the simple depiction of static anatomical snapshots to capturing temporal processes as well as to covering multiple scales of physiology eventually linking molecular biology to medicine. The visualization of human physiology complements other techniques, for example lab tests for quantifying certain physiological functions. We deem ourselves at the beginning of an interesting extension of MedViz research to increasingly capture physiology in addition to anatomy.", pdf = "pdfs/2015-10-25--VIS2015--TutTalkHH--print2up.pdf", images = "images/ThumbnailVisTut.png", thumbnails = "images/ThumbnailVisTut.png", day = "25", location = "Chicago, Illinois, USA" } @MISC {LeMusic14Temporal, author = "Mathieu Le Muzic and Julius Parulek and Manuela Waldner and Ivan Viola", title = "Illustrative Visualization of Biochemical Processes Featuring Multiple Temporal Scales", howpublished = "Poster presented at the EG VCBM workshop 2014", month = "September", year = "2014", pdf = "pdfs/LeMusic14Temporal.pdf", images = "images/LeMuzic14Temporal.png", thumbnails = "images/LeMuzic14Temporal_thumb.png", location = "Wien, Austria", project = "physioillustration" } @MISC {Kingman14PARP1, author = "Pina Kingman and Anne-Kristin Stavrum and Ivan Viola and Helwig Hauser", title = "PARP-1 Binds Damaged DNA", howpublished = "Poster presented at the VizBi conference 2014", month = "March", year = "2014", abstract = "This image is an excerpt from the animation entitled Negative charge and poly(ADP)-ribosylation: a scientific animation. The molecules where uploaded from the Protein Data Bank using the Embedded Python Molecular Viewer plug-in for Autodesk Maya (Johnson et al. 2001; Sanner et al. 1996). The scene was rendered using Maxon Cinema 4D and composited in Adobe Photoshop. Subsurface Scattering was chosen to give the molecules a translucent appearance. Two PARP-1 molecules are shown bound to damaged DNA (Coquelle and Glover 2012). This work has been carried out within the PhysioIllustration project (funded by NFR, project #218023).", images = "images/Kingman13PARP1.jpg", thumbnails = "images/Kingman13PARP1_thumb.jpg", location = "Heidelberg, Germany", project = "physioillustration" } @MISC {Kingman14Integrating, author = "Pina Kingman and Anne-Kristin Stavrum and Ivan Viola and Helwig Hauser", title = "Integrating 2D and 3D Animation to Comprehensively Communicate Biology", howpublished = "Poster presented at the VizBi conference 2014", month = "March", year = "2014", abstract = "As research in cellular and molecular biology advances, so does the need to educated both the science research community and the general public. The former must be aware of developments in associated fields, the latter must be able to take responsibility for their own well-being. In both cases, we have a willing and capable audience, ready to delve deeper into the biological sciences. To exploit this opportunity, we need to research new and advanced visual language techniques to further improve communication. We are therefore investigating novel visual communication techniques to advance knowledge translation methods, focusing on effectively communicating abstract functional aspects of biological systems. To this end, we are creating several short animations, each one exploring different design solutions. These design solutions incorporate 2D motion graphics, information visualization, 3D animation, and can be applied to any biological story. In addition to our short animations, this research will culminate in a short film describing NAD-dependent DNA Repair, intended for the general public and researchers interested in these molecular systems.", images = "images/Kingman13Integrating.png", thumbnails = "images/Kingman13Integrating_thumb.jpg", location = "Heidelberg, Germany", project = "physioillustration" } @MISC {Kingman14ResilientGenome, author = "Pina Kingman", title = "Our Resilient Genome", howpublished = "Talk in the Forshkningsdagene UNG 2014", month = "September", year = "2014", abstract = "Motivation: Make science research accessible to the public through film. Inspire and instil an interest in science and molecular biology. Story: The short animated film will describe the molecular pathways involved in single strand break DNA repair. Every single human cell has to repair an estimated 10,000-20,000 DNA lesion every day. DNA is constantly exposed to a variety of genotoxic events, leading to many different types of lesions. If the damage is not repaired, these lesions may lead to mutations that in turn lead to cancer and ageing. Your cells, however, have fine tuned mechanisms that maintain the integrity of our genome. This film describes one of those mechanisms. Length: About 3 minutes. Audience: We are aiming for the type of person who would attend a science film festival. We are thus assuming an interest in biology and medicine, at least a high-school degree (with the high probability of intending to continue to higher education), and a basic understanding of biology. Timeline: The film is currently in production and will be finished mid/late summer.", images = "images/no_thumb.png", thumbnails = "images/no_thumb.png", location = "Bergen, Norway", project = "physioillustration" } @MISC {Kingman14GenomeMaking, author = "Pina Kingman", title = "Our Resilient Genome: The Making of a Science Film", howpublished = "Presentation in the EG VCBM workshop 2014", month = "September", year = "2014", abstract = "Every single human cell has to fix 10,000 to 20,000 lesions in its DNA every day. Our cells are constantly exposed to many different types of threats that damage our genome. These lesions could cause mutations in our DNA, potentially leading to cancer and other diseases. With such continuous onslaught, how can our cells possibly protect our DNA from damage and mutations? This presentation will showcase the first public screening of a short film about DNA repair, which blends computer graphics and biology to communicate exciting up-and-coming research. This film was developed in conjunction with the Department of Informatics and the Department of Molecular Biology at the University of Bergen, and the Institute of Computer Graphics and Algorithms at the Vienna University of Technology. Along with a discussion on the visualisation process, I will also talk about the intersection between film and science that helps us communicate complex information.", images = "images/no_thumb.png", thumbnails = "images/no_thumb.png", location = "Wien, Austria", project = "physioillustration" } @ARTICLE {Angelelli14Interactive, author = "Paolo Angelelli and Steffen Oeltze and Cagatay Turkay and Judit Haasz and Erlend Hodneland and Arvid Lundervold and Astri Johansen Lundervold and Bernhard Preim and Helwig Hauser", title = "Interactive Visual Analysis of Heterogeneous Cohort Study Data", journal = "Computer Graphics and Applications, IEEE", year = "2014", volume = "PP", number = "99", pages = "1-1", abstract = "Cohort studies are used in medicine to enable the study of medical hypotheses in large samples. Often, a large amount of heterogeneous data is acquired from many subjects. The analysis is usually hypothesis-driven, i.e., a specific subset of such data is studied to confirm or reject specific hypotheses. In this paper, we demonstrate how we enable the interactive visual exploration and analysis of such data, helping with the generation of new hypotheses and contributing to the process of validating them. We propose a data-cube based model which allows to handle partially overlapping data subsets during the interactive visualization. This model enables the seamless integration of the heterogeneous data, as well as the linking of spatial and non-spatial views on these data. We implemented this model in an application prototype, and used it to analyze data acquired in the context of a cohort study on cognitive aging. In this paper we present a case-study analysis of selected aspects of brain connectivity by using a prototype implementation of the presented model, to demonstrate its potential and flexibility.", vid = "vids/angelelli14CohortExplorer.wmv", images = "images/angelelli14Cohort.png", thumbnails = "images/angelelli14Cohort.png", doi = "10.1109/MCG.2014.40", url = "http://dx.doi.org/10.1109/MCG.2014.40" } @MISC {Brambilla14Visualizing, author = "Andrea Brambilla", title = "Visualizing the Long-term Behavior of 3D Fluid Flows", howpublished = "Presentation at the Konversatorium, Institute for Computer Graphics and Algorithm, TU Wien", month = "April", year = "2014", abstract = "The study of the long-term behavior of 3D fluid flows can provide useful insights into transport phenomena, which are of central importance in many fields, such as medicine and engineering. Such a study is normally based on the integration of the flow field. The resulting integral structures are indeed highly expressive, but their direct visualization often suffers from cluttering and occlusion issues. In this talk I will present my recent (and future) work addressing this problem. Three projects will be covered: (1) A seeding strategy for families of integral surfaces, which captures the predominant aspects of the long-term flow behavior. (2) A technique for easing the investigation and comparison of surface families, based on a 2D reformation process. (3) The work I am carrying out here at the TU, aimed at quantifying transport phenomena and depicting them using Sankey diagrams.", images = "images/Brambilla14Visualizing.png", thumbnails = "images/Brambilla14Visualizing.png", location = "Wien, Austria", url = "http://www.cg.tuwien.ac.at/courses/konversatorium/2014-04-25", pres = "pdfs/Brambilla14Visualizing.pdf" } @MISC {Brambilla14Visibility, author = "Andrea Brambilla", title = "Visibility Management in Integration-based Flow Visualization", howpublished = "Talk at the Department of Informatics, Systems and Communication, University of Milano - Bicocca", month = "June", year = "2014", abstract = "The analysis of flow phenomena holds an important role in several fields, such as engineering and medicine. Flow visualization techniques aim at easing the investigation process by depicting the flow data through graphical entities. Specifically, integration-based methods employ lines and surfaces in order to visualize the long-term behavior of fluid particles. In this talk, I will give a brief introduction to integration-based flow visualization, present its advantages and discuss its main limitations, i.e., cluttering and occlusion. I will then present my recent work addressing these limitations. Two projects will be described: (1) A selection strategy for integral surfaces, which aims at detecting a small number of highly informative integral surfaces. (2) A technique for easing the investigation and comparison of surface families, based on a 2D reformation process.", images = "images/Brambilla14Visualizing.png", thumbnails = "images/Brambilla14Visualizing.png", location = "Milan, Italy", pres = "pdfs/Brambilla14Visibility.pdf" } @ARTICLE {Natali14Sketch, author = "Mattia Natali and Tore Grane Klausen and Daniel Patel", title = "Sketch-Based Modelling and Visualization of Geological Deposition", journal = "Computers \& Geosciences", year = "2014", volume = "67C", pages = "40--48", abstract = "We propose a method for sketching and visualizing geological models by sequentially defining stratigraphic layers, where each layer represents a unique erosion or deposition event. Evolution of rivers and deltas is important for geologists when interpreting the stratigraphy of the subsurface, in particular for hydrocarbon exploration. We illustratively visualize mountains, basins, lakes, rivers and deltas, and how they change the morphology of a terrain during their evolution. We present a compact representation of the model and a novel rendering algorithm that allows us to obtain an interactive and illustrative layer-cake visualization. A user study has been performed to evaluate our method.", vid = "vids/Natali2014Sketch.mp4", images = "images/Natali2014Sketch0.png, images/Natali2014Sketch1.png", thumbnails = "images/Natali2014Sketch0.png, images/Natali2014Sketch1.png", doi = "10.1016/j.cageo.2014.02.010", url = "http://www.sciencedirect.com/science/article/pii/S0098300414000508", project = "geoillustrator" } @ARTICLE {Natali14Rapid, author = "Mattia Natali and Julius Parulek and Daniel Patel", title = "Rapid Modelling of Interactive Geological Illustrations with Faults and Compaction", journal = "Proceedings of Spring Conference on Computer Graphics (SCCG)", year = "2014", abstract = "In this paper, we propose new methods for building geological illustrations and animations. We focus on allowing geologists to create their subsurface models by means of sketches, to quickly communicate concepts and ideas rather than detailed information. The result of our sketch-based modelling approach is a layer-cake volume representing geological phenomena, where each layer is rock material which has accumulated due to a user-defined depositional event. Internal geological structures can be inspected by different visualization techniques that we employ. Faulting and compaction of rock layers are important processes in geology. They can be modelled and visualized with our technique. Our representation supports non-planar faults that a user may define by means of sketches. Real-time illustrative animations are achieved by our GPU accelerated approach.", pdf = "pdfs/Natali14Rapid.pdf", images = "images/Natali2014Rapid0.png, images/Natali2014Rapid1.png", thumbnails = "images/Natali2014Rapid0.png, images/Natali2014Rapid1.png", url = "http://dx.doi.org/10.1145/2643188.2643201", project = "geoillustrator" } @ARTICLE {Parulek14Continuous, author = "Julius Parulek and Daniel J{\"o}nsson and Timo Ropinski and Stefan Bruckner and Anders Ynnerman and Ivan Viola", title = "Continuous Levels-of-Detail and Visual Abstraction for Seamless Molecular Visualization", journal = "Computer Graphics Forum", year = "2014", pages = "n/a--n/a", abstract = "Molecular visualization is often challenged with rendering of large molecular structures in real time. We introduce a novel approach that enables us to show even large protein complexes. Our method is based on the level-of-detail concept, where we exploit three different abstractions combined in one visualization. Firstly, molecular surface abstraction exploits three different surfaces, solvent-excluded surface (SES), Gaussian kernels and van der Waals spheres, combined as one surface by linear interpolation. Secondly, we introduce three shading abstraction levels and a method for creating seamless transitions between these representations. The SES representation with full shading and added contours stands in focus while on the other side a sphere representation of a cluster of atoms with constant shading and without contours provide the context. Thirdly, we propose a hierarchical abstraction based on a set of clusters formed on molecular atoms. All three abstraction models are driven by one importance function classifying the scene into the near-, mid- and far-field. Moreover, we introduce a methodology to render the entire molecule directly using the A-buffer technique, which further improves the performance. The rendering performance is evaluated on series of molecules of varying atom counts.", pdf = "pdfs/Parulek14Continuous.pdf", images = "images/Parulek14Continuous0.png, images/Parulek14Continuous1.png, images/Parulek14Continuous2.png", thumbnails = "images/Parulek14Continuous0_thumb.png, images/Parulek14Continuous1_thumb.png, images/Parulek14Continuous2_thumb.png", issn = "1467-8659", url = "http://dx.doi.org/10.1111/cgf.12349", doi = "10.1111/cgf.12349", project = "physioillustration" } @ARTICLE {lemuzic2014ivm, author = "Mathieu Le Muzic and Julius Parulek and Anne-Kristin Stavrum and Ivan Viola", title = "Illustrative Visualization of Molecular Reactions using Omniscient Intelligence and Passive Agents ", journal = "Computer Graphics Forum", year = "2014", volume = "33", number = "3", pages = "141--150", month = "jun", abstract = "In this paper we propose a new type of a particle systems, tailored for illustrative visualization purposes, in particular for visualizing molecular reactions in biological networks. Previous visualizations of biochemical processes were exploiting the results of agent-based modeling. Such modeling aims at reproducing accurately the stochastic nature of molecular interactions. However, it is impossible to expect events of interest happening at a certain time and location, which is impractical for storytelling. To obtain the means of controlling molecular interactions, we propose to govern passive agents with an omniscient intelligence, instead of giving to the agents the freedom of initiating reaction autonomously. This makes it possible to generate illustrative animated stories that communicate the functioning of the molecular machinery. The rendering performance delivers for interactive framerates of massive amounts of data, based on the dynamic tessellation capabilities of modern graphics cards. Finally, we report an informal expert feedback we obtained from the potential users.", images = "images/Lemuzic14Illustrative.png, images/Lemuzic14Illustrative.png", thumbnails = "images/Lemuzic14Illustrative0_thumb.png, images/Lemuzic14Illustrative1_thumb.png", event = "EuroVis", url = "http://www.cg.tuwien.ac.at/research/publications/2014/lemuzic-2014-ivm/", project = "physioillustration" } @PHDTHESIS {natali14thesis, author = "Mattia Natali", title = "Sketch-based Modelling and Conceptual Visualization of Geomorphological Processes for Interactive Scientific Communication", school = "Department of Informatics, University of Bergen, Norway", year = "2014", month = "September", abstract = "Throughout this dissertation, solutions for rapid digitalization of ideas will be defined.More precisely, the focus is on interactive scientific sketching and communication of geology, where theresult is a digital illustrative 3D model. Results are achieved through a sketch-based modellingapproach which gives the user a more natural and intuitive modelling process, hence leading to aquicker definition of a geological illustration. To be able to quickly externalize and communicate onesideas as a digital 3D model, can be of importance. For instance, students may profit from explanationssupported by interactive illustrations. Exchange of information and hypotheses between domain expertsis also a targeted situation in our work. Furthermore, illustrative models are frequently employed in business, when decisional meetings take place for convincing the management that a project is worth to be funded. An advantage of digital models is that they can be saved and they are easy to distribute. In contrast to 2D images or paper sketches, one can interact with digital 3D models, and they can be transferred on portable devices for easy access (for instance during geological field studies). Another advantage, compared to standard geological illustrations, is that if a model has been created with internal structures, it can be arbitrarily cut and inspected. Different solutions for different aspects of subsurface geology are presented in this dissertation. To express folding and faulting processes, a first modelling approach based on cross-sectional sketches is introduced. User defined textures can be associated to each layer, and can then be deformed with sketch strokes, for communicating layer properties such as rock type and grain size. A following contribution includes a simple and compact representation to model and visualize 3D stratigraphic models. With this representation, erosion and deposition offluvial systems are easy to specify and display. Ancient river channels and other geological features, which are present in the subsurface, can be accessed by means of a volumetric representation. Geological models are obtained and visualized by sequentially defining stratigraphic layers, where each layer represents a unique erosion or deposition event. Evolution of rivers and deltas is important for geologists when interpreting the stratigraphy of the subsurface, in particular because it changes the landscape morphology and because river deposits are potential hydrocarbon reservoirs. Time plays a fundamental role in geological processes. Animations are well suited for communicating temporal change and a contribution in this direction is also given. With the techniques developed in this thesis, it becomes possible to produce a range of geological scenarios. The focus is on enabling geologists tocreate their subsurface models by means of sketches, to quickly communicate concepts and ideasrather than detailed information. Although the proposed techniques are simple to use and requirelittle design effort, complex models can be realized. ", pdf = "pdfs/natali14thesis.pdf", images = "images/Natali2014Rapid0.png, images/Natali2014Sketch0.png,", thumbnails = "images/Natali2014Rapid0.png, images/Natali2014Sketch0.png,", isbn = "?? ", url = "https://bora.uib.no/handle/1956/8570", project = "geoillustrator" } @ARTICLE {Kolesar14InteractivePolymers, author = "Ivan Kolesar and Julius Parulek and Ivan Viola and Stefan Bruckner and Anne-Kristin Stavrum and Helwig Hauser", title = "Interactively illustrating polymerization using three-level model fusion", journal = "BMC Bioinformatics 2014", year = "2014", volume = "15", pages = "345", month = "October", abstract = "Background Research in cell biology is steadily contributing new knowledge about many aspects of physiological processes, both with respect to the involved molecular structures as well as their related function. Illustrations of the spatio-temporal development of such processes are not only used in biomedical education, but also can serve scientists as an additional platform for in-silico experiments. Results In this paper, we contribute a new, three-level modeling approach to illustrate physiological processes from the class of polymerization at different time scales. We integrate physical and empirical modeling, according to which approach best suits the different involved levels of detail, and we additionally enable a form of interactive steering, while the process is illustrated. We demonstrate the suitability of our approach in the context of several polymerization processes and report from a first evaluation with domain experts. Conclusion We conclude that our approach provides a new, hybrid modeling approach for illustrating the process of emergence in physiology, embedded in a densely filled environment. Our approach of a complementary fusion of three systems combines the strong points from the different modeling approaches and is capable to bridge different spatial and temporal scales.", pdf = "pdfs/Kolesar14Interactive.pdf", images = "images/Kolesar14Interactive.png", thumbnails = "images/Kolesar14Interactive_thumb.png", url = "http://www.biomedcentral.com/1471-2105/15/345", doi = "10.1186/1471-2105-15-345", issn = "1471-2105", project = "physioillustration" } @MISC {Brambilla14Video, author = "Andrea Brambilla", title = "Video Visualization: An Overview", howpublished = "Trial lecture, University of Bergen", month = "November", year = "2014", abstract = "Videos are one of the most widespread media for collecting, communicating and archiving information. Nowadays, acquiring videos is a relatively straightforward process, and this explains their success in the context of entertainment, surveillance, sport events, and so on. On the other hand, watching and extracting information from a video stream is a lengthy process. Automatic techniques are only partially sucessful because of the intrinsic complexity of this kind of data. Video visualization is a growing research field which aims at easying the study of video data. It relies on both automatic techniques and user interaction, exploiting the best of both worlds. In this talk, I will introduce this field, focusing on its evolution from computer vision. I will discuss the main challenges and present an overview of the state-of-the-art. The talk will conclude with a discussion of the open problems and the expected future developments.", images = "images/Brambilla14Video.png", thumbnails = "images/Brambilla14Video.png", location = "Bergen, Norway", pres = "pdfs/Brambilla14Video.pptx" } @INCOLLECTION {peikert2014comparison, author = "Ronald Peikert and Armin Pobitzer and Filip Sadlo and Benjamin Schindler", title = "A Comparison of Finite-Time and Finite-Size Lyapunov Exponents", booktitle = "Topological Methods in Data Analysis and Visualization III", publisher = "Springer International Publishing", year = "2014", editor = "Peer-Timo Bremer and Ingrid Hotz and Valerio Pascucci and Ronald Peikert", series = "Mathematics and Visualization", pages = "187--200", images = "images/peikert2014comparison.png", thumbnails = "images/peikert2014comparison_thumb.png", doi = "10.1007/978-3-319-04099-8_12", url = "http://dx.doi.org/10.1007/978-3-319-04099-8_12", isbn = "978-3-319-04098-1" } @PHDTHESIS {brambilla14thesis, author = "Andrea Brambilla", title = "Visibility-oriented Visualization Design for Flow Illustration", school = "Department of Informatics, University of Bergen, Norway", year = "2014", month = "December", abstract = "Flow phenomena are ubiquitous in our world and they affect many aspects of our daily life. For this reason, they are the subject of extensive studies in several research fields. In medicine, the blood flow through our vessels can reveal important information about cardiovascular diseases. The air flow around a vehicle and the motion of fluids in a combustion engine are examples of relevant flow phenomena in engineering disciplines. Meteorologists, climatologists and oceanographers are instead concerned with winds and water currents. Thanks to the recent advancements in computational fluid dynamics and to the increasing power of modern hardware, accurate simulations of flow phenomena are feasible nowadays. The evolution of multiple flow attributes, such as velocity, temperature and pressure, can be simulated over large spatial and temporal domains (4D). The amount of data generated by this process is massive, therefore visualization techniques are often adopted in order to ease the analysis phase. The overall goal is to convey information about the phenomena of interest through a suitable representation of the data at hand. Due to the multivariate and multidimensional nature of the data, visibility issues (such as cluttering and occlusion), represent a significant challenge. Flow visualization can greatly benefit from studying and addressing visibility issues already in the design phase. In this thesis we investigate and demonstrate the effectiveness of taking visibility management into account early in the design process. We apply this principle to three characteristic flow visualization scenarios: (1) The simultaneous visualization of multiple flow attributes. (2) The visual inspection of single and multiple integral surfaces. (3) The selection of seeding curves for constructing families of integral surfaces. Our techniques result in clutter- and occlusion-free visualizations, which effectively illustrate the key aspects of the flow behavior. For demonstration purposes, we have applied our approaches to a number of application cases. Additionally, we have discussed our visualization designs with domain experts. They showed a genuine interest in our work and provided insightful suggestions for future research directions.", images = "images/brambilla14thesis_0.png, images/brambilla14thesis_1.png,", thumbnails = "images/brambilla14thesis_0_thumb.png, images/brambilla14thesis_1_thumb.png,", isbn = "978-82-308-2753-6", url = "http://hdl.handle.net/1956/8961" } @INCOLLECTION {Pfister2014VIC, author = "Hanspeter Pfister and Verena Kaynig and Charl P. Botha and Stefan Bruckner and Vincent J. Dercksen and Hans-Christian Hege and Jos B.T.M. Roerdink", title = "Visualization in Connectomics", booktitle = "Scientific Visualization: Uncertainty, Multifield, Biomedical, and Scalable Visualization", publisher = "Springer", year = "2014", editor = "Min Chen and Hans Hagen and Charles D. Hansen and Christopher R. Johnson and Arie E. Kaufman", series = "Mathematics and Visualization", chapter = "21", pages = "221--245", month = "sep", abstract = "Connectomics is a branch of neuroscience that attempts to create a connectome, i.e., a completemap of the neuronal system and all connections between neuronal structures. This representation can be used to understand how functional brain states emerge from their underlying anatomical structures and how dysfunction and neuronal diseases arise. We review the current state-of-the-art of visualization and image processing techniques in the field of connectomics and describe a number of challenges. After a brief summary of the biological background and an overview of relevant imaging modalities, we review current techniques to extract connectivit", pdf = "pdfs/Pfister-2014-VIC.pdf", images = "images/Pfister-2014-VIC.jpg", thumbnails = "images/Pfister-2014-VIC.png", doi = "10.1007/978-1-4471-6497-5_21", keywords = "connectomics, neuroscience, visualization, imaging", owner = "bruckner", timestamp = "2014.12.30", url = "http://www.springer.com/mathematics/computational+science+%26+engineering/book/978-1-4471-6496-8" } @INCOLLECTION {Amirkhanov2014HSH, author = "Artem Amirkhanov and Stefan Bruckner and Christoph Heinzl and Meister Eduard Gr{\"o}ller", title = "The Haunted Swamps of Heuristics: Uncertainty in Problem Solving", booktitle = "Scientific Visualization: Uncertainty, Multifield, Biomedical, and Scalable Visualization", publisher = "Springer", year = "2014", editor = "Min Chen and Hans Hagen and Charles D. Hansen and Christopher R. Johnson and Arie E. Kaufman", series = "Mathematics and Visualization", chapter = "5", pages = "51--60", month = "sep", abstract = "In scientific visualization the key task of research is the provision of insight into a problem. Finding the solution to a problem may be seen as finding a path through some rugged terrain which contains mountains, chasms, swamps, and few flatlands. This path - an algorithm discovered by the researcher - helps users to easily move around this unknown area. If this way is a wide road paved with stones it will be used for a long time by many travelers. However, a narrow footpath leading through deep forests and deadly swamps will attract only a few adventure seekers. There are many different paths with different levels of comfort, length, and stability, which are uncertain during the research process. Finding a systematic way to deal with this uncertainty can greatly assist the search for a safe path which is in our case the development of a suitable visualization algorithm for a specific problem. In this work we will analyze the sources of uncertainty in heuristically solving visualization problems and will propose directions to handle these uncertainties.", pdf = "pdfs/Amirkhanov-2014-HSH.pdf", images = "images/Amirkhanov-2014-HSH.jpg", thumbnails = "images/Amirkhanov-2014-HSH.png", doi = "10.1007/978-1-4471-6497-5_5", keywords = "uncertainty, heuristics, problem solving", owner = "bruckner", timestamp = "2014.12.30", url = "http://www.springer.com/mathematics/computational+science+%26+engineering/book/978-1-4471-6496-8" } @ARTICLE {Sedlmair2014VPS, author = "Michael Sedlmair and Christoph Heinzl and Stefan Bruckner and Harald Piringer and Torsten M{\"o}ller", title = "Visual Parameter Space Analysis: A Conceptual Framework", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2014", volume = "20", number = "12", pages = "2161--2170", month = "dec", abstract = "Various case studies in different application domains have shown the great potential of visual parameter space analysis to support validating and using simulation models. In order to guide and systematize research endeavors in this area, we provide a conceptual framework for visual parameter space analysis problems. The framework is based on our own experience and a structured analysis of the visualization literature. It contains three major components: (1) a data flow model that helps to abstractly describe visual parameter space analysis problems independent of their application domain; (2) a set of four navigation strategies of how parameter space analysis can be supported by visualization tools; and (3) a characterization of six analysis tasks. Based on our framework, we analyze and classify the current body of literature, and identify three open research gaps in visual parameter space analysis. The framework and its discussion are meant to support visualization designers and researchers in characterizing parameter space analysis problems and to guide their design and evaluation processes.", pdf = "pdfs/Sedlmair-2014-VPS.pdf", images = "images/Sedlmair-2014-VPS.jpg", thumbnails = "images/Sedlmair-2014-VPS.png", doi = "10.1109/TVCG.2014.2346321", event = "IEEE VIS 2014", keywords = "parameter space analysis, input-output model, simulation, task characterization, literature analysis", location = "Paris, France" } @ARTICLE {Rautek2014VSI, author = "Peter Rautek and Stefan Bruckner and Meister Eduard Gr{\"o}ller and Markus Hadwiger", title = "ViSlang: A System for Interpreted Domain-Specific Languages for Scientific Visualization", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2014", volume = "20", number = "12", pages = "2388--2396", month = "dec", abstract = "Researchers from many domains use scientific visualization in their daily practice. Existing implementations of algorithms usually come with a graphical user interface (high-level interface), or as software library or source code (low-level interface). In this paper we present a system that integrates domain-specific languages (DSLs) and facilitates the creation of new DSLs. DSLs provide an effective interface for domain scientists avoiding the difficulties involved with low-level interfaces and at the same time offering more flexibility than high-level interfaces. We describe the design and implementation of ViSlang, an interpreted language specifically tailored for scientific visualization. A major contribution of our design is the extensibility of the ViSlang language. Novel DSLs that are tailored to the problems of the domain can be created and integrated into ViSlang. We show that our approach can be added to existing user interfaces to increase the flexibility for expert users on demand, but at the same time does not interfere with the user experience of novice users. To demonstrate the flexibility of our approach we present new DSLs for volume processing, querying and visualization. We report the implementation effort for new DSLs and compare our approach with Matlab and Python implementations in terms of run-time performance.?", pdf = "pdfs/Rautek-2014-VSI.pdf", images = "images/Rautek-2014-VSI.jpg", thumbnails = "images/Rautek-2014-VSI.png", youtube = "https://www.youtube.com/watch?v=DbWazwyMRNw", doi = "10.1109/TVCG.2014.2346318", event = "IEEE VIS 2014", keywords = "domain-specific languages, volume visualization, volume visualization framework", location = "Paris, France", url = "http://vcc.kaust.edu.sa/Pages/Pub-ViSlang-Sys-Int-Dom-Spe-Lang-SC.aspx" } @ARTICLE {Mindek2014MSS, author = "Peter Mindek and Meister Eduard Gr{\"o}ller and Stefan Bruckner", title = "Managing Spatial Selections with Contextual Snapshots", journal = "Computer Graphics Forum", year = "2014", volume = "33", number = "8", pages = "132--144", month = "dec", abstract = "Spatial selections are a ubiquitous concept in visualization. By localizing particular features, they can be analysed and compared in different views. However, the semantics of such selections often depend on specific parameter settings and it can be difficult to reconstruct them without additional information. In this paper, we present the concept of contextual snapshots as an effective means for managing spatial selections in visualized data. The selections are automatically associated with the context in which they have been created. Contextual snapshots can also be used as the basis for interactive integrated and linked views, which enable in-place investigation and comparison of multiple visual representations of data. Our approach is implemented as a flexible toolkit with well-defined interfaces for integration into existing systems. We demonstrate the power and generality of our techniques by applying them to several distinct scenarios such as the visualization of simulation data, the analysis of historical documents and the display of anatomical data.", pdf = "pdfs/Mindek-2014-MSS.pdf", images = "images/Mindek-2014-MSS.jpg", thumbnails = "images/Mindek-2014-MSS.png", youtube = "https://www.youtube.com/watch?v=rxEf-Okp8Xo", doi = "10.1111/cgf.12406", keywords = "interaction, visual analytics, spatial selections, annotations", url = "http://www.cg.tuwien.ac.at/downloads/csl/" } @MISC {Hauser2014BigData, author = "Helwig Hauser", title = "Big Data - a threat or an opportunity for our modern society?", howpublished = "Invited talk at the Alumni Event of the University of Bergen, Norway", month = "May", year = "2014", abstract = "Invited talk at the Alumni Event of the University of Bergen, Norway", pdf = "pdfs/2014-05-10--UiB-Alumni--BigDataTalkHH--print2up.pdf", images = "images/2014-05-10--UiB-Alumni--BigDataTalkHH--print2up_Image_0003.jpg", thumbnails = "images/2014-05-10--UiB-Alumni--BigDataTalkHH--print2up_Image_0003.jpg", location = "Bergen, Norway" } @MISC {Hauser2014NCE, author = "Helwig Hauser", title = "About Visual Computing", howpublished = "Invited talk at the NCE Subsea Theme Meeting on Visual Computing in Bergen, Norway", month = "April", year = "2014", abstract = "Invited talk at the NCE Subsea Theme Meeting on Visual Computing in Bergen, Norway", pdf = "pdfs/2014-04-08--VisCompTalk--HH--print2up.pdf", images = "images/2014-04-08--VisCompTalk--HH--print2up_Image_0004.jpg, images/2014-04-08--VisCompTalk--HH--print2up_Image_0006.jpg, images/2014-04-08--VisCompTalk--HH--print2up_Image_0010.jpg, images/2014-04-08--VisCompTalk--HH--print2up_Image_0002.jpg", thumbnails = "images/2014-04-08--VisCompTalk--HH--print2up_Image_0010.jpg", location = "Bergen, Norway" } @MISC {Hauser2014Dagstuhl, author = "Helwig Hauser", title = "Semi-abstract visualization of rich scientific data", howpublished = "Invited talk at the Dagstuhl 14231 Seminar on Scientific Visualization, Dagstuhl, Germany", month = "June", year = "2014", abstract = "Invited talk at the Dagstuhl 14231 Seminar on Scientific Visualization, Dagstuhl, Germany", pdf = "pdfs/2014-06-06--Dagstuhl--SemiAbstractSciVis--print2up.pdf", images = "images/2014-06-06--Dagstuhl--SemiAbstractSciVis--print2up_Image_0002(3).jpg, images/2014-06-06--Dagstuhl--SemiAbstractSciVis--print2up_Image_0002(2).jpg, images/2014-06-06--Dagstuhl--SemiAbstractSciVis--print2up_Image_0002.jpg, images/2014-06-06--Dagstuhl--SemiAbstractSciVis--print2up_Image_0008.jpg", thumbnails = "images/2014-06-06--Dagstuhl--SemiAbstractSciVis--print2up_Image_0002(3).jpg", location = "Dagstuhl, Germany" } @MISC {Hauser2014USP, author = "Helwig Hauser", title = "About Visualization in Bergen and Interactive Visual Analysis", howpublished = "Invited talk at Institute of Computing and Mathematical Sciences, University of São Paolo, in São Carlos, Brazil", month = "August", year = "2014", abstract = "Invited talk at Institute of Computing and Mathematical Sciences, University of São Paolo, in São Carlos, Brazil", pdf = "pdfs/2014-08-26--SaoCarlos--USP-inv-talk-print2up.pdf", images = "images/2014-08-26--SaoCarlos--USP-inv-talk-print2up_Image_0001.jpg, images/2014-08-26--SaoCarlos--USP-inv-talk-print2up_Image_0001(2).jpg, images/2014-08-26--SaoCarlos--USP-inv-talk-print2up_Image_0001(3).jpg, images/2014-08-26--SaoCarlos--USP-inv-talk-print2up_Image_0001(4).jpg, images/2014-08-26--SaoCarlos--USP-inv-talk-print2up_Image_0002.jpg, images/2014-08-26--SaoCarlos--USP-inv-talk-print2up_Image_0003.jpg, images/2014-08-26--SaoCarlos--USP-inv-talk-print2up_Image_0003(2).jpg, images/2014-08-26--SaoCarlos--USP-inv-talk-print2up_Image_0002(2).jpg, images/2014-08-26--SaoCarlos--USP-inv-talk-print2up_Image_0002(3).jpg", thumbnails = "images/2014-08-26--SaoCarlos--USP-inv-talk-print2up_Image_0001.jpg", location = "São Carlos, Brazil" } @MISC {Hauser2014SIBGRAPI, author = "Helwig Hauser", title = "Interactive Visual Exploration and Analysis of Multi-Faceted Scientific Data", howpublished = "Invited talk at SIBGRAPI Conference on Graphics, Patterns and Images in Rio de Janeiro, Brazil", month = "August", year = "2014", abstract = "Invited talk at SIBGRAPI Conference on Graphics, Patterns and Images in Rio de Janeiro, Brazil", pdf = "pdfs/2014-08-30--Rio--SIBGRAPI-invited-talk--print-new-new-2up.pdf", images = "images/2014-08-30--Rio--SIBGRAPI-invited-talk--print-new-new-2up_Image_0003.jpg, images/2014-08-30--Rio--SIBGRAPI-invited-talk--print-new-new-2up_Image_0001.jpg, images/2014-08-30--Rio--SIBGRAPI-invited-talk--print-new-new-2up_Image_0001(2).jpg, images/2014-08-30--Rio--SIBGRAPI-invited-talk--print-new-new-2up_Image_0001(3).jpg, images/2014-08-30--Rio--SIBGRAPI-invited-talk--print-new-new-2up_Image_0001(4).jpg", thumbnails = "images/2014-08-30--Rio--SIBGRAPI-invited-talk--print-new-new-2up_Image_0003.jpg", location = "Rio de Janeiro, Brazil", doi = "10.1007/978-1-4471-6497-5_15" } @MASTERTHESIS {Smestad14thesis, author = "Geir Smestad", title = "Interactive Visual Analysis of Streaming Data", school = "Visualization Group, Department of Informatics, University of Bergen", year = "2014", type = "MSc. thesis", month = "aug", images = "images/AgeEmphasis.PNG,images/Snapshots.PNG,images/TotalInterface4.PNG,images/wholebuffer-movingaverage.PNG,", thumbnails = "images/AgeEmphasis.PNG,images/Snapshots.PNG,images/TotalInterface4.PNG,images/wholebuffer-movingaverage.PNG," } @INCOLLECTION {RobertLaramee2014HSH, author = "Robert Laramee and Hamish Carr and Min Chen and Helwig Hauser and Lars Linsen and Klaus Mueller and Vijay Natarajan and Harald Obermaier and Ronald Peikert and Eugene Zhang", title = "Future Challenges and Unsolved Problems in Multi-field Visualization", booktitle = "Scientific Visualization: Uncertainty, Multifield, Biomedical, and Scalable Visualization", publisher = "Springer", year = "2014", editor = "Min Chen and Hans Hagen and Charles D. Hansen and Christopher R. Johnson and Arie E. Kaufman", series = "Mathematics and Visualization", chapter = "19", pages = "205-211", month = "sep", images = "images/no_thumb.png", thumbnails = "images/no_thumb.png", doi = "10.1007/978-1-4471-6497-5_19", keywords = "uncertainty, heuristics, problem solving", owner = "hausser", timestamp = "2015.02.06", isbn = "978-1-4471-6496-8", url = "http://www.springer.com/mathematics/computational+science+%26+engineering/book/978-1-4471-6496-8" } @ARTICLE {turkay2014attribute, author = "Turkay, Cagatay and Slingsby, Aidan and Hauser, Helwig and Wood, Jo and Dykes, Jason", title = "Attribute signatures: Dynamic visual summaries for analyzing multivariate geographical data", journal = "Visualization and Computer Graphics, IEEE Transactions on", year = "2014", volume = "20", number = "12", pages = "2033--2042", abstract = "The visual analysis of geographically referenced datasets with a large number of attributes is challenging due to the fact that the characteristics of the attributes are highly dependent upon the locations at which they are focussed, and the scale and time at which they are measured. Specialized interactive visual methods are required to help analysts in understanding the characteristics of the attributes when these multiple aspects are considered concurrently. Here, we develop attribute signatures-interactively crafted graphics that show the geographic variability of statistics of attributes through which the extent of dependency between the attributes and geography can be visually explored. We compute a number of statistical measures, which can also account for variations in time and scale, and use them as a basis for' our visualizations. We then employ different graphical configurations to show and compare both continuous and discrete variation of location and scale. Our methods allow variation in multiple statistical summaries of multiple attributes to be considered concurrently and geographically, as evidenced by examples in which the census geography of London and the wider UK are explored.", images = "images/img_Page_06_Image_0003.jpg, images/img_Page_01_Image_0002.jpg, images/img_Page_01_Image_0005.jpg, images/img_Page_07_Image_0003.jpg", thumbnails = "images/img_Page_06_Image_0003.jpg", publisher = "IEEE", doi = "10.1109/TVCG.2014.2346265" } @INCOLLECTION {turkay2014computationally, author = "Turkay, Cagatay and Jeanquartier, Fleur and Holzinger, Andreas and Hauser, Helwig", title = "On computationally-enhanced visual analysis of heterogeneous data and its application in biomedical informatics", booktitle = "Interactive Knowledge Discovery and Data Mining in Biomedical Informatics", publisher = "Springer", year = "2014", pages = "117--140", abstract = "With the advance of new data acquisition and generation technologies, the biomedical domain is becoming increasingly data-driven. Thus, understanding the information in large and complex data sets has been in the focus of several research fields such as statistics, data mining, machine learning, and visualization. While the first three fields predominantly rely on computational power, visualization relies mainly on human perceptual and cognitive capabilities for extracting information. Data visualization, similar to Human–Computer Interaction, attempts an appropriate interaction between human and data to interactively exploit data sets. Specifically within the analysis of complex data sets, visualization researchers have integrated computational methods to enhance the interactive processes. In this state-of-the-art report, we investigate how such an integration is carried out. We study the related literature with respect to the underlying analytical tasks and methods of integration. In addition, we focus on how such methods are applied to the biomedical domain and present a concise overview within our taxonomy. Finally, we discuss some open problems and future challenges.", images = "images/img_Page_12_Image_0001.jpg, images/img_Page_12_Image_0002.jpg, images/img_Page_12_Image_0003.jpg", thumbnails = "images/img_Page_12_Image_0001.jpg", doi = "10.1007/978-3-662-43968-5_7)" } @ARTICLE {turkay2014characterizing, author = "Turkay, Cagatay and Lex, Alexander and Streit, Marc and Pfister, Hanspeter and Hauser, Helwig", title = "Characterizing cancer subtypes using dual analysis in caleydo stratomex", journal = "Computer Graphics and Applications, IEEE", year = "2014", volume = "34", number = "2", pages = "38--47", abstract = "Dual analysis uses statistics to describe both the dimensions and rows of a high-dimensional dataset. Researchers have integrated it into StratomeX, a Caleydo view for cancer subtype analysis. In addition, significant-difference plots show the elements of a candidate subtype that differ significantly from other subtypes, thus letting analysts characterize subtypes. Analysts can also investigate how data samples relate to their assigned subtype and other groups. This approach lets them create well-defined subtypes based on statistical properties. Three case studies demonstrate the approach's utility, showing how it reproduced findings from a published subtype characterization.", images = "images/img_Page_08_Image_0001.jpg, images/img_Page_04_Image_0001.jpg", thumbnails = "images/img_Page_08_Image_0001.jpg", publisher = "IEEE", doi = "10.1109/MCG.2014.1" } @ARTICLE {alsallakh2014visual, author = "Alsallakh, Bilal and Hanbury, Allan and Hauser, Helwig and Miksch, Silvia and Rauber, Andreas", title = "Visual methods for analyzing probabilistic classification data", journal = "Visualization and Computer Graphics, IEEE Transactions on", year = "2014", volume = "20", number = "12", pages = "1703--1712", abstract = "Multi-class classifiers often compute scores for the classification samples describing probabilities to belong to different classes. In order to improve the performance of such classifiers, machine learning experts need to analyze classification results for a large number of labeled samples to find possible reasons for incorrect classification. Confusion matrices are widely used for this purpose. However, they provide no information about classification scores and features computed for the samples. We propose a set of integrated visual methods for analyzing the performance of probabilistic classifiers. Our methods provide insight into different aspects of the classification results for a large number of samples. One visualization emphasizes at which probabilities these samples were classified and how these probabilities correlate with classification error in terms of false positives and false negatives. Another view emphasizes the features of these samples and ranks them by their separation power between selected true and false classifications. We demonstrate the insight gained using our technique in a benchmarking classification dataset, and show how it enables improving classification performance by interactively defining and evaluating post-classification rules.", images = "images/alsallakh2014visual3.jpg, images/alsallakh2014visual1.jpg, images/alsallakh2014visual2.jpg", thumbnails = "images/alsallakh2014visual3.jpg", publisher = "IEEE" } @ARTICLE {matkovic2014visual, author = "Matkovic, Kresimir and Gracanin, Denis and Splechtna, Rainer and Jelovic, Mario and Stehno, Benedikt and Hauser, Helwig and Purgathofer, Werner", title = "Visual analytics for complex engineering systems: Hybrid visual steering of simulation ensembles", journal = "Visualization and Computer Graphics, IEEE Transactions on", year = "2014", volume = "20", number = "12", pages = "1803--1812", abstract = "In this paper we propose a novel approach to hybrid visual steering of simulation ensembles. A simulation ensemble is a collection of simulation runs of the same simulation model using different sets of control parameters. Complex engineering systems have very large parameter spaces so a naïve sampling can result in prohibitively large simulation ensembles. Interactive steering of simulation ensembles provides the means to select relevant points in a multi-dimensional parameter space (design of experiment). Interactive steering efficiently reduces the number of simulation runs needed by coupling simulation and visualization and allowing a user to request new simulations on the fly. As system complexity grows, a pure interactive solution is not always sufficient. The new approach of hybrid steering combines interactive visual steering with automatic optimization. Hybrid steering allows a domain expert to interactively (in a visualization) select data points in an iterative manner, approximate the values in a continuous region of the simulation space (by regression) and automatically find the “best” points in this continuous region based on the specified constraints and objectives (by optimization). We argue that with the full spectrum of optimization options, the steering process can be improved substantially. We describe an integrated system consisting of a simulation, a visualization, and an optimization component. We also describe typical tasks and propose an interactive analysis workflow for complex engineering systems. We demonstrate our approach on a case study from automotive industry, the optimization of a hydraulic circuit in a high pressure common rail Diesel injection system.", images = "images/matkovic2014visual1.jpg, images/matkovic2014visual2.jpg", thumbnails = "images/matkovic2014visual1.jpg", publisher = "IEEE" } @INCOLLECTION {HH2014CATEGORIZATION, author = "Helwig Hauser, Hamish Carr", title = "Multifield Visualization - Categorization", booktitle = "Scientific Visualization: Uncertainty, Multifield, Biomedical, and Scalable Visualization", publisher = "Springer", year = "2014", editor = "Min Chen and Hans Hagen and Charles D. Hansen and Christopher R. Johnson and Arie E. Kaufman", series = "Mathematics and Visualization", pages = "111-117", month = "sep", images = "images/no_thumb.png", thumbnails = "images/no_thumb.png", doi = "10.1007/978-1-4471-6497-5_19", keywords = "uncertainty, heuristics, problem solving", owner = "hausser", timestamp = "2015.02.06", isbn = "978-1-4471-6496-8", url = "http://www.springer.com/mathematics/computational+science+%26+engineering/book/978-1-4471-6496-8" } @INCOLLECTION {GW2014IVA, author = "Gunther Weber, Helwig Hauser", title = "Interactive Visual Exploration and Analysis", booktitle = "Scientific Visualization: Uncertainty, Multifield, Biomedical, and Scalable Visualization", publisher = "Springer", year = "2014", editor = "Min Chen and Hans Hagen and Charles D. Hansen and Christopher R. Johnson and Arie E. Kaufman", series = "Mathematics and Visualization", pages = "161-173", month = "sep", images = "images/HH-2014-IVA1.jpg, images/HH-2014-IVA2.jpg, images/HH-2014-IVA3.jpg", thumbnails = "images/HH-2014-IVA1.jpg", doi = "10.1007/978-1-4471-6497-5_19", keywords = "uncertainty, heuristics, problem solving", owner = "hausser", timestamp = "2015.02.06", isbn = "978-1-4471-6496-8", url = "http://www.springer.com/mathematics/computational+science+%26+engineering/book/978-1-4471-6496-8" } @INCOLLECTION {DC2014GlyphBased, author = "David Chung, Robert Laramee, Johannes Kehrer, Helwig Hauser", title = "Glyph-Based Multi-field Visualization", booktitle = "Scientific Visualization: Uncertainty, Multifield, Biomedical, and Scalable Visualization", publisher = "Springer", year = "2014", editor = "Min Chen and Hans Hagen and Charles D. Hansen and Christopher R. Johnson and Arie E. Kaufman", series = "Mathematics and Visualization", pages = "129-137", month = "sep", images = "images/DC-2014-GlyphBased1.jpg, images/DC-2014-GlyphBased2.jpg", thumbnails = "images/DC-2014-GlyphBased1.jpg", doi = "10.1007/978-1-4471-6497-5_19", keywords = "uncertainty, heuristics, problem solving", owner = "hausser", timestamp = "2015.02.06", isbn = "978-1-4471-6496-8", url = "http://www.springer.com/mathematics/computational+science+%26+engineering/book/978-1-4471-6496-8" } @MISC {Hauser2014HiB, author = "Helwig Hauser", title = "Interactive Visual Analysis of Rich Scientific Data", howpublished = "Invited talk at the Bergen University College in Bergen, Norway", month = "November", year = "2014", abstract = "Invited talk at the Bergen University College in Bergen, Norway", pdf = "pdfs/2014-11-25--BergenHIB--InvitedTalk--print2up--web.pdf", images = "images/2014-11-25--BergenHIB--InvitedTalk--print2up--web_Image_0002.jpg, images/2014-11-25--BergenHIB--InvitedTalk--print2up--web_Image_0003.jpg, images/2014-11-25--BergenHIB--InvitedTalk--print2up--web_Image_0005.jpg, images/2014-11-25--BergenHIB--InvitedTalk--print2up--web_Image_0002(2).jpg, images/2014-11-25--BergenHIB--InvitedTalk--print2up--web_Image_0009.jpg, images/2014-11-25--BergenHIB--InvitedTalk--print2up--web_Image_0002(3).jpg, images/2014-11-25--BergenHIB--InvitedTalk--print2up--web_Image_0009(2).jpg, images/2014-11-25--BergenHIB--InvitedTalk--print2up--web_Image_0003(2).jpg, images/2014-11-25--BergenHIB--InvitedTalk--print2up--web_Image_0007.jpg, images/2014-11-25--BergenHIB--InvitedTalk--print2up--web_Image_0005(2).jpg", thumbnails = "images/2014-11-25--BergenHIB--InvitedTalk--print2up--web_Image_0002.jpg", location = "Bergen, Norway" } @ARTICLE {Karimov2013VSV, author = "Alexey Karimov and Gabriel Mistelbauer and Johanna Schmidt and Peter Mindek and Elisabeth Schmidt and Timur Sharipov and Stefan Bruckner and Meister Eduard Gr{\"o}ller", title = "ViviSection: Skeleton-based Volume Editing", journal = "Computer Graphics Forum", year = "2013", volume = "32", number = "3", pages = "461--470", month = "jun", abstract = "Volume segmentation is important in many applications, particularly in the medical domain. Most segmentation techniques, however, work fully automatically only in very restricted scenarios and cumbersome manual editing of the results is a common task. In this paper, we introduce a novel approach for the editing of segmentation results. Our method exploits structural features of the segmented object to enable intuitive and robust correction and verification. We demonstrate that our new approach can significantly increase the segmentation quality even in difficult cases such as in the presence of severe pathologies.", pdf = "pdfs/Karimov-2013-VSV.pdf", images = "images/Karimov-2013-VSV.jpg", thumbnails = "images/Karimov-2013-VSV.png", event = "EuroVis 2013", keywords = "volume visualization, volume editing, segmentation, interaction", location = "Leipzig, Germany", url = "http://www.cg.tuwien.ac.at/research/publications/2013/karimov-2013-vivisection/" } @MASTERTHESIS {Bendiksen13thesis, author = "Morten Bendiksen", title = "Rapid Modeling of Geology", school = "Visualization Group, Department of Informatics, University of Bergen", year = "2013", type = "MSc. thesis", month = "mar", images = "images/P013_I001.jpg,images/P013_I002.jpg,images/P067_I004.jpg,images/P069_I002.jpg,images/P070_I002.jpg,", thumbnails = "images/P013_I001.jpg,images/P013_I002.jpg,images/P067_I004.jpg,images/P069_I002.jpg,images/P070_I002.jpg," } @PHDTHESIS {turkay13thesis, author = "Cagatay Turkay", title = "Integrating Computational Tools in Interactive and Visual Methods for Enhancing High-dimensional Data and Cluster Analysis", school = "Department of Informatics, University of Bergen, Norway", year = "2013", month = "November", abstract = "With the advance of new data acquisition and generation technologies, our society is becoming increasingly information-driven. The datasets are getting larger and more complex as new technologies emerge and they are posing new challenges to the analysts who are trying to build an understanding of them. Automated computational approaches and interactive visual methods have been widely used to extract and interpret the relevant information in data analysis. However when these methods are used alone on complex datasets, their effectivity is limited due to several factors. Most of the commonly used computational tools often lead to hard to interpret results that may not be reliable most of the time. This thesis aims to enhance data analysis procedures by integrating computational tools with interactive visual methodologies. The contributions of this thesis are mainly focused on the analysis of (very) high-dimensional data, i.e., hundreds and even thousands of dimensions, and cluster analysis. We introduce the dual analysis approach that makes it possible to analyze the items and the dimensions of a dataset in parallel in two linked visualization spaces. This methodology provides a basis to visually characterize and investigate dimensions as first-order analysis objects. We describe structure-aware analysis procedures that are facilitated by representative factors. Moreover, we present several mechanisms to achieve outlier-aware analysis routines. We describe the notion of outlyingness for the dimensions of a dataset and discuss how they can be determined and treated properly. We then focus on enhancing the dialogue between the analyst and the computer when computational methods are used interactively. We describe how different human factors come into play in visual analysis applications and propose optimized analytical processes that try to comply with the human capabilities. All these different approaches are demonstrated with various use-cases performed mostly together with experts from medical, genetic, and molecular biology domain. ", pdf = "pdfs/turkay13thesis.pdf", images = "images/turkay13thesis.png", thumbnails = "images/turkay13thesis.png", isbn = "?? ", project = "medviz" } @MISC {Kingman13ScienceFilm, author = "Pina Kingman", title = "Animating Biology: The making of a science film", howpublished = "Presentation in the VisBio 2013", month = "September", year = "2013", abstract = "Biology is complicated. Understanding cellular and molecular biology is particularly difficult. Amongst the many effective communication tools at our disposal, animated film is at the forefront. Animation brings biological stories to life, and thus aids in our understanding of biological structure and function. Whether used to inform patients, to teach undergraduate biology, or to disseminate advances in research, animated film is a tool worth employing. But what goes into an animation? I will explain the step-by-step process of creating animations and show a lot of inspiring examples.", images = "images/no_thumb.png", thumbnails = "images/no_thumb.png", location = "Bergen, Norway", project = "physioillustration" } @MISC {Parulek13Analysis, author = "Julius Parulek", title = "Interactive Visual Exploration and Analysis of High-Dimensional, Temporal, and Heterogeneous Biological Data", howpublished = "Presentation in the VisBio 2013", month = "September", year = "2013", abstract = "High-dimensional data (hundreds of dimensions, or more) and temporal data (thousands of time frames) pose substantial challenges for both computational and interactive analysis. To reveal relevant intrinsic relations between items or dimensions, the utilization of only computational methods or standard visualization techniques is not enough. In this talk, we introduce the concept of interactive visual analysis (IVA) that enables us to combine computational methods with the user knowledge through a system of multiple linked views on the data and advanced interaction mechanisms. Our approach allows us to interact with the data on the level of individual items and also on the level of dimensions, exploiting a number of useful statistical methods in addition. To improve the understanding of temporal data, we utilize clustering methods, where the user is provided means to understand the internal cluster structure. Moreover, we also showcase how IVA can be beneficial when analyzing molecular dynamics.", images = "images/no_thumb.png", thumbnails = "images/no_thumb.png", location = "Bergen, Norway", project = "physioillustration" } @MISC {Kolesar13HumanPhysiology, author = "Ivan Kolesar", title = "Approaches for Visualizing Human Physiology", howpublished = "Presentation in the VisBio 2013", month = "September", year = "2013", abstract = "Physiology is scientific study of function in living systems. All in all, we presents several visual abstractions used to communicate physiological processes through different functional human systems in different scales from molecules to whole human body. However there are still several challenges for visualizing multi-scale physiological processes.", images = "images/no_thumb.png", thumbnails = "images/Kolesar13HumanPhysiology.jpg", location = "Bergen, Norway", project = "physioillustration" } @ARTICLE {Lovset13Rule, author = "Tyge L{\o }vset and Dag Magne Ulvang and Tor Christian Bekkvik and K{\aa}re Villanger and Ivan Viola", title = "Rule-based method for automatic scaffold assembly from 3D building models", journal = "Computers \& Graphics", year = "2013", volume = "37", number = "4", pages = "256--268", abstract = "To manually specify an optimal scaffold assembly for a given building geometry is a time consuming task. Our goal is to automate the process of selecting and placing scaffold components in order to design an optimal scaffold assembly for a specific building. The resulting assembly must be possible to construct in practice, should be practical to use for the workers, must satisfy governmental rules and regulations and should ideally result in minimum accumulated component cost. We propose a novel procedural modeling pipeline based on an input house model. First we extract vital coordinates from the house model that define the 3D scaffold placement. These coordinates are the basis for defining the positioning of scaffold cells. In the next step we populate the cells with actual scaffold components geometry. The resulting model is visualized to assist the assembly process. Additionally it is decomposed into elementary building blocks to produce assembly component lists to estimate the scaffold cost estimates, compute the weight for transportation and packing of components from a warehouse. The result from the automated process is compared to scaffold design produced manually by a professional scaffold designer.", images = "images/Lovset13Rule01.png, images/Lovset13Rule02.png", thumbnails = "images/Lovset13Rule01_thumb.png, images/Lovset13Rule02_thumb.png", issn = "0097-8493", doi = "10.1016/j.cag.2013.01.007", url = "http://www.sciencedirect.com/science/article/pii/S0097849313000095" } @ARTICLE {Lidal13Geological, author = "Endre M. Lidal and Mattia Natali and Daniel Patel and Helwig Hauser and Ivan Viola", title = "Geological storytelling", journal = "Computers \& Graphics", year = "2013", volume = "37", number = "5", pages = "445--459 ", abstract = "Developing structural geological models from exploratory subsea imaging is difficult and an ill-posed process. The structural geological processes that take place in the subsurface are both complex and time-dependent. We present Geological Storytelling, a novel graphical system for performing rapid and expressive geomodeling. Geologists can convey geological stories that externalize both their model and the reasoning process behind it through our simple, yet expressive sketch-based, flip-over canvases. This rapid modeling interface makes it easy to construct a large variety of geological stories, and our story tree concept facilitates easy management and the exploration of these alternatives. The stories are then animated and the geologists can examine and compare them to identify the most plausible models. Finally, the geological stories can be presented as illustrative animations of automatically synthesized 3D models, which efficiently communicate the complex geological evolution to non-experts and decision makers. Geological storytelling provides a complete pipeline from the ideas and knowledge in the mind of the geologist, through externalized artifacts specialized for discussion and knowledge dissemination among peer-experts, to automatically rendered illustrative 3D animations for communication to lay audience. We have developed geological storytelling in collaboration with domain experts that work with the modeling challenges on a daily basis. For evaluation, we have developed a geological storytelling prototype and presented it to experts and academics from the geosciences. In their feedback, they acknowledge that the rapid and expressive sketching of stories can make them explore more alternatives and that the 3D illustrative animations assist in communicating their models.", images = "images/Lidal13Geological01.jpg, images/Lidal13Geological02.png", thumbnails = "images/Lidal13Geological01.jpg, images/Lidal13Geological02.png", issn = "0097-8493", doi = "http://dx.doi.org/10.1016/j.cag.2013.01.010\"", url = "http://www.sciencedirect.com/science/article/pii/S0097849313000125", keywords = "Sketch-based modeling; Externalization of mental processes; Storytelling; 3D model synthesis; Animation; Alternatives exploration; Geology; Structural geological models", project = "geoillustrator" } @ARTICLE {Kehrer13VisualizationAnd, author = "Johannes Kehrer and Helwig Hauser", title = "Visualization and Visual Analysis of Multi-faceted Scientific Data: a Survey", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2013", volume = "19", number = "3", pages = "495-513", abstract = "Visualization and visual analysis play important roles in exploring, analyzing and presenting scientific data. In many disciplines, data and model scenarios are becoming multi-faceted: data are often spatio-temporal and multi-variate; they stem from different data sources (multi-modal data), from multiple simulation runs (multi-run/ensemble data), or from multi-physics simulations of interacting phenomena (multi-model data resulting from coupled simulation models). Also, data can be of different dimensionality or structured on various types of grids that need to be related or fused in the visualization. This heterogeneity of data characteristics presents new opportunities as well as technical challenges for visualization research. Visualization and interaction techniques are thus often combined with computational analysis. In this survey, we study existing methods for visualization and interactive visual analysis of multi-faceted scientific data. Based on a thorough literature review, a categorization of approaches is proposed. We cover a wide range of fields and discuss to which degree the different challenges are matched with existing solutions for visualization and visual analysis. This leads to conclusions with respect to promising research directions, for instance, to pursue new solutions for multi-run and multi-model data as well as techniques that support a multitude of facets.", pdf = "pdfs/Kehrer13VisualizationAnd.pdf", images = "images/Kehrer13VisualizationAnd01.png", thumbnails = "images/Kehrer13VisualizationAnd01_thumb.png", issn = "1077-2626", doi = "http://doi.ieeecomputersociety.org/10.1109/TVCG.2012.110", publisher = "IEEE Computer Society", address = "Los Alamitos, CA, USA" } @PHDTHESIS {lidal13thesis, author = "Endre M. Lidal", title = "Sketch-based Storytelling for Cognitive Problem Solving", school = "Department of Informatics, University of Bergen, Norway", year = "2013", month = "June", abstract = "Problem solving is an important part of all engineering and scientific activities. It is present, for instance, when experts want to develop more fuel- efficient cars or when they are searching for oil and gas in the subsurface. Many alternatives have to be examined and evaluated before the optimal solution is found. Solving such problems is not only performed inside the mind of the scientist, but it is also an interaction between mind and scribbles, sketches, or visualizations on papers, on blackboards, and on computers. For problem solving in expert teams, this externalization through sketches and visualizations also plays an important communicative role. This dissertation presents research for assisting the problem- solving process on the computer, through novel technological advances in the fields of illustrative visualization and sketch-based modeling. Specifically, it targets problems that are related to evolutionary processes. Firstly, inspired by storytelling, the domain experts can express their ideas for solution as stories. These stories are based on sketches that the experts draw, utilizing a novel temporal-sketching interface inspired by a flip-over canvas metaphor. Further, the dissertation describes a set of sketching proxy geometries, such as the box-proxy geometry, that the experts can take advantage of when drawing three-dimensional (3D) sketches. These proxy geometries support the task of mapping a two-dimensional input (2D), e.g., a mouse or a digitizer tablet, to a 3D sketch. Solving difficult problems require that many different solutions are evaluated to identify the most optimal one. This dissertation introduces the story-tree, a tree-graph data structure and visualization, which manages and provides access to an ensemble of alternative stories. The story- tree also provides an interface where the stories can be evaluated and compared. This playback of the stories is done through automatic animations of the 2D sketches. The third challenge addressed in this dissertation is to communicate the optimal solution to decision-makers and laymen. By combining the animated 2D story sketches with illustrative visualization techniques it is possible to automatically synthesize and animate 3D models. These animations can be combined with new cutaway visualization techniques to reveal features hidden inside such 3D models. All of these contributions have been investigated in the context of the problemsolving tasks relevant to the early phase of petroleum exploration. This phase is characterized by having very little ground-through data available. Thus, a large solution space needs to be explored. Even so, the geologists need to produce models that can predict if petroleum is present. In addition to working with few data, the geologists also work under heavy time constraints because of the competition between the oil companies exploring the same area. The contributions from this dissertation have created enthusiasm among the domain experts and already, a new research initiative has materialized from the work described in this dissertation. Based on the feedback from the domain experts, we can conclude that the contributions presented in this dissertation form a valuable step towards better tools for problem solving, involving the computer, for the domain investigated here. ", pdf = "pdfs/lidal13thesis.pdf", images = "images/lidal13thesis.png", thumbnails = "images/lidal13thesis.png", isbn = "978-82-308-2330-9", project = "geoillustrator" } @ARTICLE {Sima13Computer, author = "Aleksandra Sima and Xavier Bonaventura and Miquel Feixas and Mateu Sbert and John Howell and Ivan Viola and Simon Buckley", title = "Computer-aided image geometry analysis and subset selection for optimizing texture quality in photorealistic models", journal = "Computers and Geosciences", year = "2013", volume = "52", pages = "281-291", abstract = "Photorealistic 3D models are used for visualization, interpretation and spatial measurement in many disciplines, such as cultural heritage, archaeology and geoscience. Using modern image- and laser-based 3D modelling techniques, it is normal to acquire more data than is finally used for 3D model texturing, as images may be acquired from multiple positions, with large overlap, or with different cameras and lenses. Such redundant image sets require sorting to restrict the number of images, increasing the processing efficiency and realism of models. However, selection of image subsets optimized for texturing purposes is an example of complex spatial analysis. Manual selection may be challenging and time-consuming, especially for models of rugose topography, where the user must account for occlusions and ensure coverage of all relevant model triangles. To address this, this paper presents a framework for computer- aided image geometry analysis and subset selection for optimizing texture quality in photorealistic models. The framework was created to offer algorithms for candidate image subset selection, whilst supporting refinement of subsets in an intuitive and visual manner. Automatic image sorting was implemented using algorithms originating in computer science and information theory, and variants of these were compared using multiple 3D models and covering image sets, collected for geological applications. The image subsets provided by the automatic procedures were compared to manually selected sets and their suitability for 3D model texturing was assessed. Results indicate that the automatic sorting algorithms are a promising alternative to manual methods. An algorithm based on a greedy solution to the weighted set-cover problem provided image sets closest to the quality and size of the manually selected sets. The improved automation and more reliable quality indicators make the photorealistic model creation workflow more accessible for application experts, increasing the user’s confidence in the final textured model completeness.", images = "images/Sima13Computer01.png, images/Sima13Computer02.png", thumbnails = "images/Sima13Computer01_thumb.png, images/Sima13Computer02_thumb.png", doi = "10.1016/j.cageo.2012.11.004", url = "http://www.sciencedirect.com/science/article/pii/S0098300412003743" } @ARTICLE {Parulek13Fast, author = "Julius Parulek and Andrea Brambilla", title = "Fast Blending Scheme for Molecular Surface Representation", journal = "Visualization and Computer Graphics, IEEE Transactions on", year = "2013", pages = "2653--2662", month = "Dec.", abstract = "Representation of molecular surfaces is a well established way to study the interaction of molecules. The state-of-theart molecular representation is the SES model, which provides a detailed surface visualization. Nevertheless, it is computationally expensive, so the less accurate Gaussian model is traditionally preferred. We introduce a novel surface representation that resembles the SES and approaches the rendering performance of the Gaussian model. Our technique is based on the iterative blending of implicit functions and avoids any pre-computation. Additionally, we propose a GPU-based ray-casting algorithm that efficiently visualize our molecular representation. A qualitative and quantitative comparison of our model with respect to the Gaussian and SES models is presented. As showcased in the paper, our technique is a valid and appealing alternative to the Gaussian representation. This is especially relevant in all the applications where the cost of the SES is prohibitive.", pdf = "pdfs/Parulek13Fast.pdf", images = "images/Parulek13Fast01.png, images/Parulek13Fast02.png", thumbnails = "images/Parulek13Fast01_thumb.png, images/Parulek13Fast02_thumb.png", event = "Vis2013", project = "physioillustration", extra = "extra/Parulek13Fast_code.pdf" } @ARTICLE {Parulek13Visual, author = "Julius Parulek and Cagatay Turkay and Nathalie Reuter and Ivan Viola", title = "Visual cavity analysis in molecular simulations", journal = "BMC Bioinformatics", year = "2013", volume = "14", number = "Suppl 19", pages = "S4", month = "Nov.", abstract = "Molecular surfaces provide a useful mean for analyzing interactions between biomolecules; such as identification and characterization of ligand binding sites to a host macromolecule. We present a novel technique, which extracts potential binding sites, represented by cavities, and characterize them by 3D graphs and by amino acids. The binding sites are extracted using an implicit function sampling and graph algorithms. We propose an advanced cavity exploration technique based on the graph parameters and associated amino acids. Additionally, we interactively visualize the graphs in the context of the molecular surface. We apply our method to the analysis of MD simulations of Proteinase 3, where we verify the previously described cavities and suggest a new potential cavity to be studied.", images = "images/Parulek13Visual01.png, images/Parulek13Visual02.png", thumbnails = "images/Parulek13Visual01_thumb.png, images/Parulek13Visual02_thumb.png", url = "http://www.biomedcentral.com/1471-2105/14/S19/S4", doi = "10.1186/1471-2105-14-S19-S4", issn = "1471-2105", project = "physioillustration" } @ARTICLE {Patel2013ICS, author = "Daniel Patel and Veronika \v{S}olt{\'e}szov{\'a} and Jan Martin Nordbotten and Stefan Bruckner", title = "Instant Convolution Shadows for Volumetric Detail Mapping", journal = "ACM Transactions on Graphics", year = "2013", volume = "32", number = "5", pages = "154:1--154:18", month = "sep", abstract = "In this article, we present a method for rendering dynamic scenes featuring translucent procedural volumetric detail with all-frequency soft shadows being cast from objects residing inside the view frustum. Our approach is based on an approximation of physically correct shadows from distant Gaussian area light sources positioned behind the view plane, using iterative convolution. We present a theoretical and empirical analysis of this model and propose an efficient class of convolution kernels which provide high quality at interactive frame rates. Our GPU-based implementation supports arbitrary volumetric detail maps, requires no precomputation, and therefore allows for real-time modi?cation of all rendering parameters.", pdf = "pdfs/Patel-2013-ICS.pdf", images = "images/Patel-2013-ICS.jpg", thumbnails = "images/Patel-2013-ICS.png", keywords = "shadows, volumetric effects, procedural texturing, filtering", url = "http://dl.acm.org/citation.cfm?id=2492684", project = "geoillustrator" } @MASTERTHESIS {Lind13thesis, author = "Andreas Johnsen Lind", title = "Selected Opportunities for the Semiautomatic Analysis of Spectrally Decomposed Seismic Data", school = "Visualization Group, Department of Informatics, University of Bergen", year = "2013", type = "MSc. thesis", month = "aug", images = "images/P01.png,images/P02.png,images/P03.png,images/P04.png,", thumbnails = "images/P01.png,images/P02.png,images/P03.png,images/P04.png," } @ARTICLE {Alsallakh13Radial, author = "B. Alsallakh and W. Aigner and S. Miksch and H. Hauser", title = "Radial Sets: Interactive Visual Analysis of Large Overlapping Sets", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2013", volume = "19", number = "12", pages = "2496-2505", abstract = "In many applications, data tables contain multi-valued attributes that often store the memberships of the table entities to multiple sets such as which languages a person masters, which skills an applicant documents, or which features a product comes with. With a growing number of entities, the resulting element-set membership matrix becomes very rich of information about how these sets overlap. Many analysis tasks targeted at set-typed data are concerned with these overlaps as salient features of such data. This paper presents Radial Sets, a novel visual technique to analyze set memberships for a large number of elements. Our technique uses frequency-based representations to enable quickly finding and analyzing different kinds of overlaps between the sets, and relating these overlaps to other attributes of the table entities. Furthermore, it enables various interactions to select elements of interest, find out if they are over-represented in specific sets or overlaps, and if they exhibit a different distribution for a specific attribute compared to the rest of the elements. These interactions allow formulating highly-expressive visual queries on the elements in terms of their set memberships and attribute values. As we demonstrate via two usage scenarios, Radial Sets enable revealing and analyzing a multitude of overlapping patterns between large sets, beyond the limits of state-of-the-art techniques.", images = "images/Alsallakh13Radial_3.jpg, images/Alsallakh13Radial_1.jpg, images/Alsallakh13Radial_2.jpg", thumbnails = "images/Alsallakh13Radial_3_thumb.png, images/Alsallakh13Radial_1_thumb.png, images/Alsallakh13Radial_2_thumb.png", url = "http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6634104", doi = "10.1109/TVCG.2013.184", issn = "1077-2626" } @ARTICLE {Hauser13GuestEditors, author = "Helwig Hauser and Stephen Kobourov and Huamin Qu", title = "Guest Editors' Introduction: Special Section on the IEEE Pacific Visualization Symposium 2012", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2013", volume = "19", number = "6", pages = "898-899", images = "images/Gno_thumb.png", thumbnails = "images/no_thumb.png", issn = "1077-2626", url = "http://doi.ieeecomputersociety.org/10.1109/TVCG.2013.70", doi = "http://doi.ieeecomputersociety.org/10.1109/TVCG.2013.70", publisher = "IEEE Computer Society", address = "Los Alamitos, CA, USA" } @PHDTHESIS {birkeland13thesis, author = "{\AA}smund Rognerud Birkeland", title = "Ultrasonic Vessel Visualization: From Extraction to Perception", school = "Department of Informatics, University of Bergen, Norway", year = "2013", month = "March", abstract = "Ultrasound is one of the most frequently used imaging modalities in modern medicine. The high versatility and availability of ultrasound workstations is applied in various medical scenarios, such as diagnosis, treatment planning, intra-operative imaging, and more. Modern ultrasound workstations provide live imaging of anatomical structures, as well as physiological processes, such as blood flow. However, the imaging technique have a high presence of noise, a small scan sector, and are much affected by attenuation artefacts. Thus, traditional techniques for segmentation and visualization are not applicable to ultrasound data. In this theses, we present our latest advancements in segmentation and visualization techniques, tailored specifically for the characteristics of ultrasound data. We present new methods for interactive vessel segmentation for both 3D freehand and 4D ultrasound. By directly involving the examiner in the segmentation approach as well as combining data from different probe viewpoints, we are able to obtain 3D models of blood vessels rapidly and robustly. With the ability of robust vessel extraction, we introduce novel visualization techniques which utilize the previously acquired 3D vessel models. For anatomical imaging, we present a new physics-based approach for volume clipping, enhanced slice rendering and even defining curved Couinaud-surfaces. The technique creates a deformable membrane to adapt to structures in the underlying data, defined either by predefined segmentation, iso-values, or other data attributes. For functional imaging, medical ultrasound can use the Doppler principle to image blood flow. However, Doppler ultrasound only measures a projected velocity magnitude of the data. In this thesis, we present a technique that uses the direction of the blood vessels in order to reconstruct 3D blood flow from Doppler ultrasound. By extending Doppler ultrasound with this directional information, we are able to apply traditional flow visualization techniques for displaying the blood flow. Finally, we investigated the usage of moving particles as a means to depict velocity in flow visualization. Based on a series of studies targeted for motion perception, we present a new compensation model to correct for distortions in the human visual system. This model can help users to make a more consistent estimation of velocities from evaluating the motion of particles. ", pdf = "pdfs/birkeland13thesis.pdf", images = "images/birkeland13thesis.png", thumbnails = "images/birkeland13thesis_thumb.png", isbn = "?? ", project = "illustrasound, medviz, illvis" } @ARTICLE {Mistelbauer2013VVC, author = "Gabriel Mistelbauer and Anca Morar and Andrej Varchola and R{\"u}diger Schernthaner and Ivan Baclija and Arnold K{\"o}chl and Armin Kanitsar and Stefan Bruckner and Meister Eduard Gr{\"o}ller", title = "Vessel Visualization using Curvicircular Feature Aggregation", journal = "Computer Graphics Forum", year = "2013", volume = "32", number = "3", pages = "231--240", month = "jun", abstract = "Radiological investigations are common medical practice for the diagnosis of peripheral vascular diseases. Existing visualization methods such as Curved Planar Reformation (CPR) depict calcifications on vessel walls to determine if blood is still able to flow. While it is possible with conventional CPR methods to examine the whole vessel lumen by rotating around the centerline of a vessel, we propose Curvicircular Feature Aggregation (CFA), which aggregates these rotated images into a single view. By eliminating the need for rotation, vessels can be investigated by inspecting only one image. This method can be used as a guidance and visual analysis tool for treatment planning. We present applications of this technique in the medical domain and give feedback from radiologists.", pdf = "pdfs/Mistelbauer-2013-VVC.pdf", images = "images/Mistelbauer-2013-VVC.jpg", thumbnails = "images/Mistelbauer-2013-VVC.png", event = "EuroVis 2013", keywords = "medical visualization, vessel visualization, vessel reformatiation", location = "Leipzig, Germany", url = "http://www.cg.tuwien.ac.at/research/publications/2013/mistelbauer-2013-cfa/" } @ARTICLE {Mindek2013VPE, author = "Peter Mindek and Stefan Bruckner and Peter Rautek and Meister Eduard Gr{\"o}ller", title = "Visual Parameter Exploration in {GPU} Shader Space", journal = "Journal of WSCG", year = "2013", volume = "21", number = "3", pages = "225--234", month = "jun", abstract = "The wide availability of high-performance GPUs has made the use of shader programs in visualization ubiquitous.Understanding shaders is a challenging task. Frequently it is difficult to mentally reconstruct the nature and types of transformations applied to the underlying data during the visualization process. We propose a method for the visual analysis of GPU shaders, which allows the flexible exploration and investigation of algorithms, parameters, and their effects. We introduce a method for extracting feature vectors composed of several attributes of the shader, as well as a direct manipulation interface for assigning semantics to them. The user interactively classifies pixels of images which are rendered with the investigated shader. The two resulting classes, a positive class and a negative one, are employed to steer the visualization. Based on this information, we can extract a wide variety of additional attributes and visualize their relation to this classification. Our system allows an interactive exploration of shader space and we demonstrate its utility for several different applications.", pdf = "pdfs/Mindek-2013-VPE.pdf", images = "images/Mindek-2013-VPE.jpg", thumbnails = "images/Mindek-2013-VPE.png", keywords = "parameter space exploration, shader augmentation", url = "http://www.cg.tuwien.ac.at/research/publications/2013/mindek-2013-pel/" } @ARTICLE {Schmidt2013VVA, author = "Johanna Schmidt and Meister Eduard Gr{\"o}ller and Stefan Bruckner", title = "VAICo: Visual Analysis for Image Comparison", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2013", volume = "19", number = "12", pages = "2090--2099", month = "dec", abstract = "Scientists, engineers, and analysts are confronted with ever larger and more complex sets of data, whose analysis poses special challenges. In many situations it is necessary to compare two or more datasets. Hence there is a need for comparative visualization tools to help analyze differences or similarities among datasets. In this paper an approach for comparative visualization for sets of images is presented. Well-established techniques for comparing images frequently place them side-by-side. A major drawback of such approaches is that they do not scale well. Other image comparison methods encode differences in images by abstract parameters like color. In this case information about the underlying image data gets lost. This paper introduces a new method for visualizing differences and similarities in large sets of images which preserves contextual information, but also allows the detailed analysis of subtle variations. Our approach identifies local changes and applies cluster analysis techniques to embed them in a hierarchy. The results of this process are then presented in an interactive web application which allows users to rapidly explore the space of differences and drill-down on particular features. We demonstrate the flexibility of our approach by applying it to multiple distinct domains.", pdf = "pdfs/Schmidt-2013-VVA.pdf", images = "images/Schmidt-2013-VVA.jpg", thumbnails = "images/Schmidt-2013-VVA.png", event = "IEEE VIS 2013", keywords = "focus+context visualization, image set comparison, comparative visualization", url = "http://www.cg.tuwien.ac.at/research/publications/2013/schmidt-2013-vaico/" } @ARTICLE {Auzinger2013VVC, author = "Thomas Auzinger and Gabriel Mistelbauer and Ivan Baclija and R{\"u}diger Schernthaner and Arnold K{\"o}chl and Michael Wimmer and Meister Eduard Gr{\"o}ller and Stefan Bruckner", title = "Vessel Visualization using Curved Surface Reformation", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2013", volume = "19", number = "12", pages = "2858--2867", month = "dec", abstract = "Visualizations of vascular structures are frequently used in radiological investigations to detect and analyze vascular diseases. Obstructions of the blood flow through a vessel are one of the main interests of physicians, and several methods have been proposed to aid the visual assessment of calcifications on vessel walls. Curved Planar Reformation (CPR) is a wide-spread method that is designed for peripheral arteries which exhibit one dominant direction. To analyze the lumen of arbitrarily oriented vessels, Centerline Reformation (CR) has been proposed. Both methods project the vascular structures into 2D image space in order to reconstruct the vessel lumen. In this paper, we propose Curved Surface Reformation (CSR), a technique that computes the vessel lumen fully in 3D. This offers high-quality interactive visualizations of vessel lumina and does not suffer from problems of earlier methods such as ambiguous visibility cues or premature discretization of centerline data. Our method maintains exact visibility information until the final query of the 3D lumina data. We also present feedback from several domain experts.", pdf = "pdfs/Auzinger-2013-VVC.pdf", images = "images/Auzinger-2013-VVC.jpg", thumbnails = "images/Auzinger-2013-VVC.png", event = "IEEE VIS 2013", keywords = "volume Rendering, reformation, vessel, surface approximation", url = "http://www.cg.tuwien.ac.at/research/publications/2013/Auzinger_Mistelbauer_2013_CSR/" } @MISC {Parulek13Importance, author = "Julius Parulek and Timo Ropinski and Ivan Viola", title = "Importance Driven Visualization of Molecular Surfaces", howpublished = "Poster presented at the BioVis conference 2013", month = "October", year = "2013", pdf = "pdfs/Parulek13Importance.pdf", images = "images/Parulek13Importance.png", thumbnails = "images/Parulek13Importance.png", location = "Atlanta (GA)", project = "physioillustration" } @MASTERTHESIS {Sture13thesis, author = "{\O }yvind Sture", title = "Illustrative 3D visualization of seismic data", school = "Visualization Group, Department of Informatics, University of Bergen", year = "2013", type = "MSc. thesis", month = "sep", images = "images/P042_I002.jpg,images/P050_I002.jpg,images/P052_I001.jpg,images/P052_I002.jpg,images/P053_I002.jpg,images/P058_I001.jpg,", thumbnails = "images/P042_I002.jpg,images/P050_I002.jpg,images/P052_I001.jpg,images/P052_I002.jpg,images/P053_I002.jpg,images/P058_I001.jpg," } @MISC {Hauser2013VISU, author = "Helwig Hauser", title = "Interactive Visual Analysis of Scientific Data", howpublished = "Keynote talk at VISU 2013 in Paris, France", month = "November", year = "2013", abstract = "Keynote talk at VISU 2013 in Paris, France", pdf = "pdfs/2013-11-06--Paris--Visu2013--SciDataIVA--print2up--web.pdf", images = "images/2013-11-06--Paris--Visu2013--SciDataIVA--print2up--web_Image_0003.jpg, images/2013-11-06--Paris--Visu2013--SciDataIVA--print2up--web_Image_0006.jpg, images/2013-11-06--Paris--Visu2013--SciDataIVA--print2up--web_Image_0002.jpg, images/2013-11-06--Paris--Visu2013--SciDataIVA--print2up--web_Image_0002(2).jpg, images/2013-11-06--Paris--Visu2013--SciDataIVA--print2up--web_Image_0010.jpg, images/2013-11-06--Paris--Visu2013--SciDataIVA--print2up--web_Image_0008.jpg, images/2013-11-06--Paris--Visu2013--SciDataIVA--print2up--web_Image_0009.jpg, images/2013-11-06--Paris--Visu2013--SciDataIVA--print2up--web_Image_0002(3).jpg, images/2013-11-06--Paris--Visu2013--SciDataIVA--print2up--web_Image_0002(4).jpg, images/2013-11-06--Paris--Visu2013--SciDataIVA--print2up--web_Image_0006(2).jpg", thumbnails = "images/2013-11-06--Paris--Visu2013--SciDataIVA--print2up--web_Image_0003.jpg", location = "Paris, France" } @MISC {Hauser13VisTutorial, author = "Steffen Oeltze and Johannes Kehrer and Helwig Hauser", title = "Interactive Visual Analysis of Scientific Data", howpublished = "Tutorial at the IEEE VisWeek 2013", month = "October", year = "2013", abstract = "In a growing number of application areas, a subject or phenomenon is investigated by means of multiple datasets being acquired over time (spatiotemporal), comprising several attributes per data point (multi-variate), stemming from different data sources (multi-modal) or multiple simulation runs (multi-run/ensemble) [KH13]. Interactive visual analysis (IVA) comprises concepts and techniques for a user-guided knowledge discovery in such complex data. Through a tight feedback loop of computation, visualization and user interaction, it provides new insight into the data and serves as a vehicle for hypotheses generation or validation. It is often implemented via a multiple coordinated view framework where each view is equipped with interactive drill-down operations for focusing on data features. Two classes of views are integrated: physical views, such as direct volume rendering, show information in the context of the spatiotemporal observation space while attribute views, such as scatter plots and parallel coordinates, show relationships between multiple data attributes. The user may drill-down the data by selecting interesting regions of the observation space or attribute ranges leading to a consistent highlighting of this selection in all other views (brushing-and-linking). Three patterns of explorative/analytical procedures may be accomplished by doing so. In a feature localization, the user searches for places in the 3D/4D observation space where certain attribute values are present. In a multi-variate analysis, relations between data attributes are investigated, e.g., by searching for correlations. In a local investigation, the user inspects the values of selected attributes with respect to certain spatiotemporal subsets of the observation space. In this tutorial, we discuss examples for successful applications of IVA to scientific data from various fields: climate research, medicine, epidemiology, and flow simulation / computation, in particular for automotive engineering. We base our discussions on a theoretical foundation of IVA which helps the tutorial attendees in transferring the subject matter to their own data and application area. In the course of the tutorial, the attendees will become acquainted with techniques from statistics and knowledge discovery, which proved to be particularly useful for a specific IVA application. The tutorial further comprises an overview of off-the-shelf IVA solutions, which may be be particularly interesting for visualization practitioners. It is concluded by a summary of the gained knowledge and a discussion of open problems in IVA of scientific data.", images = "images/", thumbnails = "images/iva_scientificdata_proposal_2013_Image.png", location = "Atlanta (GA), USA", pres = "pdfs/iva_scientificdata_proposal_2013.pdf" } @MISC {Hauser2013IHCI, author = "Helwig Hauser", title = "Integrating Interactive and Computational Analysis in Visual Analytics", howpublished = "Keynote talk at IHCI 2013 in Prague, Czech Republic.", month = "July", year = "2013", abstract = "Keynote talk at IHCI 2013 in Prague, Czech Republic.", pdf = "pdfs/2013-07-22--Prague--IHCI--Keynote--IVA--print2up.pdf", images = "images/2013-07-22--Prague--IHCI--Keynote--IVA--print2up_Image_0001(2).jpg, images/2013-07-22--Prague--IHCI--Keynote--IVA--print2up_Image_0001(3).jpg, images/2013-07-22--Prague--IHCI--Keynote--IVA--print2up_Image_0001(4).jpg, images/2013-07-22--Prague--IHCI--Keynote--IVA--print2up_Image_0001(5).jpg, images/2013-07-22--Prague--IHCI--Keynote--IVA--print2up_Image_0001(6).jpg, images/2013-07-22--Prague--IHCI--Keynote--IVA--print2up_Image_0003.jpg", thumbnails = "images/2013-07-22--Prague--IHCI--Keynote--IVA--print2up_Image_0001(2).jpg" } @MISC {Hauser2013SouthCHI, author = "Helwig Hauser", title = "Integrating Interactive and Computational Analysis in Visualization", howpublished = "Keynote talk at SouthCHI 2013 in Maribor, Slovenia.", month = "June", year = "2013", abstract = "Keynote talk at SouthCHI 2013 in Maribor, Slovenia.", pdf = "pdfs/2013-07-02--Maribor--SouthCHI--Keynote--IVA--print2up.pdf", images = "images/2013-07-02--Maribor--SouthCHI--Keynote--IVA--print2up_Image_0001(6).jpg, images/2013-07-02--Maribor--SouthCHI--Keynote--IVA--print2up_Image_0001(5).jpg, images/2013-07-02--Maribor--SouthCHI--Keynote--IVA--print2up_Image_0001(4).jpg, images/2013-07-02--Maribor--SouthCHI--Keynote--IVA--print2up_Image_0001(3).jpg, images/2013-07-02--Maribor--SouthCHI--Keynote--IVA--print2up_Image_0001(2).jpg, images/2013-07-02--Maribor--SouthCHI--Keynote--IVA--print2up_Image_0001.jpg, images/2013-07-02--Maribor--SouthCHI--Keynote--IVA--print2up_Image_0003.jpg", thumbnails = "images/2013-07-02--Maribor--SouthCHI--Keynote--IVA--print2up_Image_0001(6).jpg" } @MISC {Smestad13Advanced, author = "Geir Smestad and Paolo Angelelli and Helwig Hauser", title = "Advanced data fusion in 4-D color doppler volume visualization", howpublished = "Poster presented at the MedIm conference 2013", month = "October", year = "2013", pdf = "pdfs/Smestad13Advanced.pdf", images = "images/Smestad13Advanced.jpg", thumbnails = "images/Smestad13Advanced_thumb.jpg", location = "Troms{\O }", project = "bia" } @INCOLLECTION {Turkay13Hypothesis, author = "Cagatay Turkay and Arvid Lundervold and Astri Johansen Lundervold and Helwig Hauser", title = "Hypothesis Generation by Interactive Visual Exploration of Heterogeneous Medical Data", booktitle = "Human-Computer Interaction and Knowledge Discovery in Complex, Unstructured, Big Data", publisher = "Springer Berlin Heidelberg", year = "2013", editor = "Holzinger, Andreas and Pasi, Gabriella", volume = "7947", series = "Lecture Notes in Computer Science", pages = "1--12", images = "images/Turkay13Hypothesis_01.png", thumbnails = "images/Turkay13Hypothesis_01.png", isbn = "978-3-642-39145-3", doi = "10.1007/978-3-642-39146-0_1", url = "http://dx.doi.org/10.1007/978-3-642-39146-0_1", keywords = "interactive visual analysis; high dimensional medical data", pres = "pdfs/Turkay13Hypothesis.pdf" } @ARTICLE {Doleish12Interactive, author = "Helmut Doleisch and Helwig Hauser", title = "Interactive Visual Exploration and Analysis of Multivariate Simulation Data", journal = "Computing in Science Engineering", year = "2012", volume = "14", number = "2", pages = "70--77", month = "March-April", abstract = "The interactive visual exploration of large and complex simulation datasets has become an important methodology that improves data analysis for scientists and professional practitioners.", images = "images/Doleish12Interactive01.png, images/Doleish12Interactive02.png", thumbnails = "images/Doleish12Interactive01_thumb.png, images/Doleish12Interactive02_thumb.png", keywords = "complex simulation datasets;data analysis;important methodology; interactive visual exploration;multivariate simulation data;data analysis; data visualisation;geophysics computing;", doi = "10.1109/MCSE.2012.27", issn = "1521-9615", url = "http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6159200" } @MISC {Viola12Physiological, author = "Ivan Viola", title = "Illustrative Visualization of Physiological Models and Imaging", howpublished = "Talk in the MedViz Conference 2012", month = "January", year = "2012", abstract = "Physiological processes are of multi-scale and multi-system nature. In general they are very difficult to comprehend. This talk discusses challenges of an upcoming research project that aims at proposing an entirely novel research agenda within the data visualization research field to enable understanding, communication, and evaluation of physiology through interactive and easy-to-understand visualization. The visualization metaphors investigated are inspired by textbook illustrations and handcrafted animated illustrations. The primary focus is on development of novel graphics data representations, visual representations, occlusion handling, visual guidance and storytelling, zooming, interaction and integration of physiological models and medical imaging. The visualization technology will be developed and evaluated on multiple scale levels, from molecular machines, up to the organ level. The physiological context for the technological development and evaluation will be primarily the muscular system. The outcome of the discussed project is new visualization technology in form of algorithms, concepts, and proof of concept implementations. The utilization of the outcome can lead to advances in the field of physiology by providing intuitive visual representation, which the user can observe and interact with.", images = "images/no_thumb.png", thumbnails = "images/no_thumb.png", location = "Bergen, Norway", project = "physioillustration, medviz" } @ARTICLE {Birkeland12Illustrative, author = "{\AA}smund Birkeland and Stefan Bruckner and Andrea Brambilla and Ivan Viola", title = "Illustrative Membrane Clipping", journal = "Computer Graphics Forum", year = "2012", volume = "31", number = "3", pages = "905--914", month = "June", abstract = "Clipping is a fast, common technique for resolving occlusions. It only requires simple interaction, is easily understandable, and thus has been very popular for volume exploration. However, a drawback of clipping is that the technique indiscriminately cuts through features. Illustrators, for example, consider the structures in the vicinity of the cut when visualizing complex spatial data and make sure that smaller structures near the clipping plane are kept in the image and not cut into fragments. In this paper we present a new technique, which combines the simple clipping interaction with automated selective feature preservation using an elastic membrane. In order to prevent cutting objects near the clipping plane, the deformable membrane uses underlying data properties to adjust itself to salient structures. To achieve this behaviour, we translate data attributes into a potential field which acts on the membrane, thus moving the problem of deformation into the soft-body dynamics domain. This allows us to exploit existing GPU-based physics libraries which achieve interactive frame rates. For manual adjustment, the user can insert additional potential fields, as well as pinning the membrane to interesting areas. We demonstrate that our method can act as a flexible and non-invasive replacement of traditional clipping planes. ", pdf = "pdfs/Birkeland12Illustrative.pdf", vid = "vids/Birkeland12Illustrative.avi", images = "images/Birkeland12Illustrative01.png, images/Birkeland12Illustrative02.png, images/Birkeland12Illustrative03.png", thumbnails = "images/Birkeland12Illustrative01_thumb.png, images/Birkeland12Illustrative02_thumb.png, images/Birkeland12Illustrative03_thumb.png", note = "presented at EuroVis 2012", event = "EuroVis 2012", location = "Vienna, Austria", keywords = "clipping, volume rendering, illustrative visualization", url = "http://www.cg.tuwien.ac.at/research/publications/2012/Birkeland-2012-IMC/", project = "illustrasound,medviz,illvis" } @MASTERTHESIS {sivertsen12thesis, author = "Stian Sivertsen", title = "Ridge Extraction, and Illustrative Visualization of an FTLE Flow Field", school = "Visualization Group, Department of Informatics, University of Bergen", year = "2012", type = "M.Sc. Thesis", month = "Oct", images = "images/sivertsen12master.png,", thumbnails = "images/sivertsen12master.png," } @ARTICLE {Brambilla12AHierarchical, author = "Andrea Brambilla and Ivan Viola and Helwig Hauser", title = "A Hierarchical Splitting Scheme to Reveal Insight into Highly Self-Occluded Integral Surfaces", journal = "Journal of WSCG", year = "2012", volume = "20", number = "1", pages = "57--64", month = "July", abstract = "In flow visualization, integral surfaces are of particular interest for their ability to describe trajectories of massless particles. In areas of swirling motion, integral surfaces can become very complex and difficult to understand. Taking inspiration from traditional illustration techniques, such as cut-aways and exploded views, we propose a surface analysis tool based on surface splitting and focus+context visualization. Our surface splitting scheme is hierarchical and at every level of the hierarchy the best cut is chosen according to a surface complexity metric. In order to make the interpretation of the resulting pieces straightforward, cuts are always made along isocurves of specific flow attributes. Moreover, a degree of interest can be specified, so that the splitting procedure attempts to unveil the occluded interesting areas. Through practical examples, we show that our approach is able to overcome the lack of understanding originating from structural occlusion.", pdf = "pdfs/Brambilla12AHierarchical.pdf", images = "images/Brambilla12AHierarchical01.png, images/Brambilla12AHierarchical02.png, images/Brambilla12AHierarchical03.png", thumbnails = "images/Brambilla12AHierarchical01_thumb.png, images/Brambilla12AHierarchical02_thumb.png, images/Brambilla12AHierarchical03_thumb.png", issn = "1213-6972", publisher = "Union Agency", url = "http://wscg.zcu.cz/JWSCG/", event = "WSCG 2012 - 20th International Conference on Computer Graphics, Visualization and Computer Vision", location = "Pilsen, Czech Republic", pres = "pdfs/Brambilla12AHierarchical.pptx", project = "semseg" } @ARTICLE {Solteszova12APerceptual, author = "Veronika \v{S}olt{\'e}szov{\'a} and Cagatay Turkay and Mark Price and Ivan Viola", title = "A Perceptual-Statistics Shading Model", journal = "Visualization and Computer Graphics, IEEE Transaction on", year = "2012", volume = "18", number = "12", pages = "2265 -2274", month = "Dec", abstract = "The process of surface perception is complex and based on several influencing factors, e.g., shading, silhouettes, occluding contours, and top down cognition. The accuracy of surface perception can be measured and the influencing factors can be modified in order to decrease the error in perception. This paper presents a novel concept of how a perceptual evaluation of a visualization technique can contribute to its redesign with the aim of improving the match between the distal and the proximal stimulus. During analysis of data from previous perceptual studies, we observed that the slant of 3D surfaces visualized on 2D screens is systematically underestimated. The visible trends in the error allowed us to create a statistical model of the perceived surface slant. Based on this statistical model we obtained from user experiments, we derived a new shading model that uses adjusted surface normals and aims to reduce the error in slant perception. The result is a shape-enhancement of visualization which is driven by an experimentally-founded statistical model. To assess the efficiency of the statistical shading model, we repeated the evaluation experiment and confirmed that the error in perception was decreased. Results of both user experiments are publicly-available datasets.", pdf = "pdfs/Solteszova12APerceptual.pdf", images = "images/Solteszova12APerceptual01.png, images/Solteszova12APerceptual02.png, images/Solteszova12APerceptual03.png", thumbnails = "images/Solteszova12APerceptual01_thumb.png, images/Solteszova12APerceptual02_thumb.png, images/Solteszova12APerceptual03_thumb.png", event = "IEEE Scientific Visualization Conference 2012", location = "Seattle, WA, USA", doi = "10.1109/TVCG.2012.188", issn = "1077--2626", extra = "extra/Solteszova12APerceptual.zip", project = "illustrasound,medviz,illvis" } @MISC {Pobitzer12NceSubsea, author = "Armin Pobitzer", title = "The State of the Art in Flow Visualization", howpublished = "Invited talk at NCS Subsea Theme Meeting - Visualization for Industrial Applications", month = "February", year = "2012", pdf = "pdfs/Pobitzer12NceSubsea.pdf", images = "images/no_thumb.png", thumbnails = "images/no_thumb.png", location = "Bergen, Norway", url = "http://eng.ncesubsea.no/page/389/activity/1029/theme-meeting-visualization-for-industrial-applications" } @MISC {Pobitzer12Physics, author = "Armin Pobitzer", title = "Physics-based Velocity Field Simplification for Flow Visualization", howpublished = "Invited talk at Minisymposium on Analysis and Representation of Large Data Sets", month = "February", year = "2012", abstract = "With the availability of more computing power, simulations of increasingly complex fluid flows have become possible. In the attempt to make sense of data, visualization has greatly gained importance in everyday scientific computing. Many visualization techniques do, however, suffer from a tendency to overly rich response in complex scenarios. Hence, filtering of the visual output is an important topic. In this talk we discuss how such filtering can be achieved in a physically meaningful way, giving examples from the extraction of vortices and Lagrangian coherent structures.", pdf = "pdfs/Pobitzer12Physics.pdf", images = "images/Pobitzer12Physics.png", thumbnails = "images/Pobitzer12Physics_thumb.png", location = "Madrid, Spain" } @MISC {Pobitzer12Exploiting, author = "Armin Pobitzer", title = "Exploiting the Turbulence Energy Cascade for Flow Visualization", howpublished = "Invited talk at the weekly seminar of Laboratoire de M\'{e}canique de Lille", month = "February", year = "2012", abstract = "Even though modern technology and tools, together with available computer power, theoretically enable us to visualise large vector fields directly, it often is neither interesting nor necessary to visualise every detail of them. Usually, interesting features of the investigated field can be visualized more efficiently using dedicated feature detectors, e.g. the $\lambda_2$ criterion [2] for vertical structures. In settings with highly complex flow patterns, such as fully developed turbulence, feature detectors may, however, mark almost the whole flow domain as a feature. In these cases visualisations based on these detectors become hard to interpret due to occlusion and visual cluttering. This problem is well known in visualisation, and has been addressed by previous work. Many of these methods have in common that they extract all features at first, and discard some of them afterwards. Criteria for this discarding are often of geometrical character, such as size (volume, length, area ...) or distance to next feature. While the visual output of such strategies satisfies the need to reduce occlusion and visual clutter, the interpretability of the results remains an open question. The immediate relation between the velocity field and the output of the feature detector is lost, since the simplication is made on the `image-level' only. In this talk we discuss how the internal structure of flow fields can be exploited, in particular the turbulence energy cascade. Based on proper orthogonal decomposition [3], we present a general simplification scheme for feature extraction that preserves the 1-to-1 relation between visual output of the method and the flow pattern it is extracted from. We apply the simplification scheme on both Eulerian and Lagrangian feature detectors and discuss the results. In particular the impact of the simplification scheme on the detection and visualization of Lagrangian Coherent Structures based on Finite-time Lyapunov exponents is addressed. The results presented in this talk are published in the article `Energy-scale Aware Feature Extraction for Flow Visualization [4]. [1] L. Hesselink, J. Helman, and P. Ning, Quantitative image processing in fluid mechanics, Experimental Thermal and Fluid Science, 5 (1992), pp. 605-616. Special Issue on Experimental Methods in Thermal and Fluid Science. [2] J. Jeong and F. Hussain, On the identification of a vortex, Journal of Fluid Mechanics, 285 (1995), pp. 69-84. [3] J. L. Lumley, The structure of inhomogeneous turbulent flows, in Atmospheric Turbulence and Radio Wave Propagation, Elsevier, 1967, pp. 166-178. [4] A. Pobitzer, M. Tutkun, O Andreassen, R. Fuchs, R. Peikert, and H. Hauser, Energy-scale aware feature extraction for flow visualization, Computer Graphics Forum, 30 (2011), pp. 771-780. [5] F. Sadlo and R. Peikert, Visualizing Lagrangian coherent structures: A comparison to vector field topology, in Topology-Based Methods in Visualization II: Proc. of the 2nd TopoInVis Workshop (TopoInVis 2007), H.-C. Hege, K. Polthier, and G. Scheuermann, eds, 2009, pp. 15-29.", images = "images/no_thumb.png", thumbnails = "images/no_thumb.png", location = "Lille, France", url = "http://lml.univ-lille1.fr/lml/?page=33\&seminID=172" } @MISC {Pobitzer12PacificVisTutorial, author = "Helwig Hauser and Alexander Kuhn and Armin Pobitzer and Maik Schulze", title = "Time-Dependent Flow Visualization", howpublished = "Tutorial at 5th IEEE PacificVis Symposium", month = "February", year = "2012", abstract = "Vector fields are a common representation of many kinds of dynamic phenomena in a large variety of application fields. A particularly interesting class of vector fields represent time-dependent flows, i.e., flows where the vectors change over time themselves. A lot of good and relevant research work has been done on the question of how to visualize such unsteady vector fields and an overview is presented in this tutorial. In particularly, we emphasize Lagrangian methods, space-time domain approaches, and interactive visual analysis as three interesting and promising types of methodology. The tutorial is also introduced with some general remarks, in particular also on the question of why it often is not straight forward to extend methods that originally were developed for steady flows to the domain of unsteady flows. A number of examples illustrate the overview.", images = "images/Pobitzer12PacificVisTutorial.png", thumbnails = "images/Pobitzer12PacificVisTutorial_thumb.png", location = "Songdo, South Korea", url = "http://www.semseg.eu/download/2012-02-28--TimeDepFlowVizTutorial--materials/" } @ARTICLE {Birkeland12TheUltrasound, author = "{\AA}smund Birkeland and Veronika \v{S}olt{\'e}szov{\'a} and Dieter H{\"o}nigmann and Odd Helge Gilja and Svein Brekke and Timo Ropinski and Ivan Viola", title = "The Ultrasound Visualization Pipeline - A Survey", journal = "CoRR", year = "2012", volume = "abs/1206.3975", abstract = "Ultrasound is one of the most frequently used imaging modality in medicine. The high spatial resolution, its interactive nature and non-invasiveness makes it the first choice in many examinations. Image interpretation is one of ultrasounds main challenges. Much training is required to obtain a confident skill level in ultrasound-based diagnostics. State-of-the-art graphics techniques is needed to provide meaningful visualizations of ultrasound in real-time. In this paper we present the process-pipeline for ultrasound visualization, including an overview of the tasks performed in the specific steps. To provide an insight into the trends of ultrasound visualization research, we have selected a set of significant publications and divided them into a technique-based taxonomy covering the topics pre-processing, segmentation, registration, rendering and augmented reality. For the different technique types we discuss the difference between ultrasound-based techniques and techniques for other modalities.", images = "images/Birkeland2012TheUltrasound.png", thumbnails = "images/Birkeland2012TheUltrasound_thumb.png", url = "http://arxiv.org/abs/1206.3975", project = "illustrasound,medviz,illvis" } @ARTICLE {Helljesen12Klinisk, author = "Linn Emilie S{\ae}vil Helljesen and Spiros Kotopoulis and Kim Nylund and Ivan Viola and Trygve Hausken and Odd Helge Gilja", title = "Klinisk bruk av 3D-ultralyd", journal = "Kirurgen", year = "2012", volume = "2", pages = "118--120", month = "June", pdf = "pdfs/Helljesen12Klinisk.pdf", images = "images/Helljesen12Klinisk01.png, images/Helljesen12Klinisk02.png", thumbnails = "images/Helljesen12Klinisk01_thumb.png, images/Helljesen12Klinisk02_thumb.png", url = "http://www.kirurgen.no/fagstoff/teknologiutvikling/klinisk-bruk-av-3d-ultralyd", project = "illustrasound,medviz" } @MISC {Helljesen12CEUS, author = "Linn Emilie S{\ae}vil Helljesen", title = "{CEUS} av leverlesjoner hos pasienter henvist etter uklare funn p{\aa} {CT} ", howpublished = "Talk at the NFUD-symposium / Frie foredrag", month = "March", year = "2012", pdf = "pdfs/Helljesen12CEUS.pdf", images = "images/no_thumb.png", thumbnails = "images/no_thumb.png", location = "Stavanger, Norway", url = "http://nfud.no/sites/default/files/Dokumenter/Programm_2012_Stavanger_kort.pdf", project = "illustrasound,medviz" } @MISC {Helljesen12Contrast, author = "Linn Emilie S{\ae}vil Helljesen and Kim Nylund and Trygve Hausken and Georg Dimcevski and Odd Helge Gilja", title = "Contrast-Enhanced Ultrasonography of liver lesions in patients referred after inconclusive findings on {CT} - Preliminary Data", howpublished = "Poster presented at the EUROSON Conference 2012", month = "April", year = "2012", abstract = "Ultralyd er kostnadseffektivt, og har blitt et nyttig verkt{\o }y i moderne klinisk diagnostikk.", pdf = "pdfs/Helljesen12Contrast.pdf", images = "images/Helljesen12Contrast01.png, images/Helljesen12Contrast02.png", thumbnails = "images/Helljesen12Contrast01_thumb.png, images/Helljesen12Contrast02_thumb.png", location = "Madrid, Spain", url = "http://kirurgen.no/fagstoff/annet/klinisk-bruk-av-3d-ultralyd/", project = "illustrasound,medviz" } @ARTICLE {Turkay12Representative, author = "Cagatay Turkay and Arvid Lundervold and Astri Johansen Lundervold and Helwig Hauser", title = "Representative Factor Generation for the Interactive Visual Analysis of High-Dimensional Data", journal = "Visualization and Computer Graphics, IEEE Transactions on", year = "2012", volume = "18", number = "12", pages = "2621--2630", month = "December", abstract = "Datasets with a large number of dimensions per data item (hundreds or more) are challenging both for computational and visual analysis. Moreover, these dimensions have different characteristics and relations that result in sub-groups and/or hierarchies over the set of dimensions. Such structures lead to heterogeneity within the dimensions. Although the consideration of these structures is crucial for the analysis, most of the available analysis methods discard the heterogeneous relations among the dimensions. In this paper, we introduce the construction and utilization of representative factors for the interactive visual analysis of structures in high-dimensional datasets. First, we present a selection of methods to investigate the sub-groups in the dimension set and associate representative factors with those groups of dimensions. Second, we introduce how these factors are included in the interactive visual analysis cycle together with the original dimensions. We then provide the steps of an analytical procedure that iteratively analyzes the datasets through the use of representative factors. We discuss how our methods improve the reliability and interpretability of the analysis process by enabling more informed selections of computational tools. Finally, we demonstrate our techniques on the analysis of brain imaging study results that are performed over a large group of subjects.", pdf = "pdfs/Turkay12Representative.pdf", vid = "vids/Turkay12Representative.avi", images = "images/Turkay12Representative01.png, images/Turkay12Representative02.png", thumbnails = "images/Turkay12Representative01_thumb.png, images/Turkay12Representative02_thumb.png", event = "IEEE Information Visualization Conference 2012", location = "Seattle, WA, USA", doi = "10.1109/TVCG.2012.256", issn = "1077-2626" } @ARTICLE {Schindler12Lagrangian, author = "Benjamin Schindler and Raphael Fuchs and Stefan Barp and Jurgen Waser and Armin Pobitzer and Robert Carnecky and Kresimir Matkovic and Ronald Peikert", title = "Lagrangian Coherent Structures for Design Analysis of Revolving Doors", journal = "Visualization and Computer Graphics, IEEE Transactions on", year = "2012", volume = "18", number = "12", pages = "2159--2168", month = "December", abstract = "Room air flow and air exchange are important aspects for the design of energy-efficient buildings. As a result, simulations are increasingly used prior to construction to achieve an energy-efficient design. We present a visual analysis of air flow generated at building entrances, which uses a combination of revolving doors and air curtains. The resulting flow pattern is challenging because of two interacting flow patterns: On the one hand, the revolving door acts as a pump, on the other hand, the air curtain creates a layer of uniformly moving warm air between the interior of the building and the revolving door. Lagrangian coherent structures (LCS), which by definition are flow barriers, are the method of choice for visualizing the separation and recirculation behavior of warm and cold air flow. The extraction of LCS is based on the finite-time Lyapunov exponent (FTLE) and makes use of a ridge definition which is consistent with the concept of weak LCS. Both FTLE computation and ridge extraction are done in a robust and efficient way by making use of the fast Fourier transform for computing scale-space derivatives.", images = "images/Schindler12Lagrangian01.png", thumbnails = "images/Schindler12Lagrangian01_thumb.png", doi = "10.1109/TVCG.2012.243", issn = "1077-2626", url = "http://visdom.at/person/5/" } @ARTICLE {Sima12AnInteractive, author = "A. A. Sima and S. J. Buckley, I. Viola", title = "An interactive tool for analysis and optimization of texture parameters in photorealistic virtual 3d models.", journal = "International Annals of Photogrammetry and Remote Sensing", year = "2012", abstract = "Texture mapping is a common method for combining surface geometry with image data, with the resulting photorealistic 3D models being suitable not only for visualisation purposes but also for interpretation and spatial measurement, in many application fields, such as cultural heritage and the earth sciences. When acquiring images for creation of photorealistic models, it is usual to collect more data than is finally necessary for the texturing process. Images may be collected from multiple locations, sometimes with different cameras or lens configurations and large amounts of overlap may exist. Consequently, much redundancy may be present, requiring sorting to choose the most suitable images to texture the model triangles. This paper presents a framework for visualization and analysis of the geometric relations between triangles of the terrain model and covering image sets. The application provides decision support for selection of an image subset optimized for 3D model texturing purposes, for non-specialists. It aims to improve the communication of geometrical dependencies between model triangles and the available digital images, through the use of static and interactive information visualisation methods. The tool was used for computer-aided selection of image subsets optimized for texturing of 3D geological outcrop models. The resulting textured models were of high quality and with a minimum of missing texture, and the time spent in time-consuming reprocessing was reduced. Anecdotal evidence indicated that an increased user confidence in the final textured model quality and completeness makes the framework highly beneficial. ", images = "images/Sima12AnInteractive01.png, images/Sima12AnInteractive02.png", thumbnails = "images/Sima12AnInteractive01_thumb.png, images/Sima12AnInteractive02_thumb.png" } @MISC {Brambilla12SemSegWorkshop, author = "Andrea Brambilla and Robert Carnecky", title = "Introduction to Illustrative Flow Visualization", howpublished = "Presentation at the 3rd SemSeg User Forum Workshop", month = "February", year = "2012", images = "images/Brambilla12Illustrative.png", thumbnails = "images/Brambilla12Illustrative_thumb.png", location = "Magdeburg, Germany", url = "http://vc.cs.ovgu.de/index.php?article_id=232", pres = "pdfs/Brambilla12SemSegWorkshop.pdf", project = "semseg" } @MISC {Hauser12SemSegWorkshop, author = "Helwig Hauser and Kresimir Matkovic", title = "Interactive Visual Analysis of Time-Dependent Flows", howpublished = "Presentation at the 3rd SemSeg User Forum Workshop", month = "February", year = "2012", images = "images/Hauser12SemSegWorkshop.png", thumbnails = "images/Hauser12SemSegWorkshop_thumb.png", location = "Magdeburg, Germany", url = "http://vc.cs.ovgu.de/index.php?article_id=232", pres = "pdfs/Hauser12SemSegWorkshop-pres.pdf", project = "semseg" } @MISC {Hauser12Dagstuhl, author = "Helwig Hauser", title = "Automated Methods in Information Visualization", howpublished = "Invited talk at the Dagstuhl seminar 12081", month = "February", year = "2012", abstract = "Visualization and Machine Learning have related goals in terms of helping analysts to understand characteristic aspects of data. While visualization aims at involving the user through interactive depictions of data, machine learning is generally represented by automatic methods that yield optimal results with respect to certain initially specified tasks. Not at the least within the research direction of visual analytics it seems promising to think about opportunities to integrate both methodologies in order to exploit the strengths of both sides. Up to now, examples of integration very often encompass the visualization of results from automatic methods as well as attempts to make originally automated methods partially interactive. A vision for the future would be to integrate interactive and automatic methods in order to solve problems. A possible realization could be an iterative process where the one or other approach is chosen on demand at each step. ", images = "images/Hauser12Dagstuhl.png", thumbnails = "images/Hauser12Dagstuhl_thumb.png", location = "Wadern, Germany", url = "http://www.dagstuhl.de/en/program/calendar/semhp/?semnr=12081", pres = "pdfs/Hauser12Dagstuhl-pres.pdf" } @MISC {Hauser12EuroVA, author = "Helwig Hauser", title = "The Iterative Process of Interactive Visual Analysis", howpublished = "Keynote talk at the EuroVA 2012 workshop", month = "June", year = "2012", abstract = "One central characteristic of our information age is that increasingly often we should exploit the wealth of available data for the sake of learning, decision making, as well as other tasks. A promising approach - not at the least also targeted by visual analytics - is to integrate the strengths of computers (fast computation, efficient handling of large datasets, comparably low costs, etc.) with the strengths of the users (perceptual capabilities, considering domain knowledge, detecting the unexpected, etc.). In this talk, we look at one possible solution, i.e., the concept of interactive visual analysis, and describe it as an iterative process, enabling the integration of computational and interactive means for data exploration and analysis. We consider a data scenario that opposes dependent and independent data dimensions (like in a table), general enough to match many different application cases. We focus on the case of multivariate data, but also address the case of high-dimensional data and opportunities for exploring and analyzing such data. After all, we think of interactive visual analysis as an iterative process, where each step is performed on the basis of a toolbox with computational and interactive visual solutions.", images = "images/Hauser12EuroVA.jpg", thumbnails = "images/Hauser12EuroVA_thumb.jpg", location = "Vienna, Austria", url = "http://www.eurova.org/previous-events/eurova-2012", pres = "pdfs/Hauser12EuroVA-pres.pdf" } @MISC {Hauser12TAVA, author = "Helwig Hauser", title = "Compromises and Added Value in Visual Analytics", howpublished = "Keynote talk at the TAVA 2012 workshop", month = "September", year = "2012", images = "images/Hauser12TAVA.png", thumbnails = "images/Hauser12TAVA_thumb.png", location = "Graz, Austria", pres = "pdfs/Hauser12TAVA-slides.pdf" } @MISC {Hauser12VCF, author = "Helwig Hauser", title = "The Iterative Process of Interactive Visual Analysis", howpublished = "Talk in the Visual Computing Forum (VCF) at UiB", month = "September", year = "2012", abstract = "One central characteristic of our information age is that increasingly often we should exploit the wealth of available data for the sake of learning, decision making, as well as other tasks. A promising approach - not at the least also targeted by visual analytics - is to integrate the strengths of computers (fast computation, efficient handling of large datasets, comparably low costs, etc.) with the strengths of the users (perceptual capabilities, considering domain knowledge, detecting the unexpected, etc.). In this talk, we look at one possible solution, i.e., the concept of interactive visual analysis, and describe it as an iterative process, enabling the integration of computational and interactive means for data exploration and analysis. We consider a data scenario that opposes dependent and independent data dimensions (like in a table), general enough to match many different application cases. We focus on the case of multivariate data, but also address the case of high-dimensional data and opportunities for exploring and analyzing such data. After all, we think of interactive visual analysis as an iterative process, where each step is performed on the basis of a toolbox with computational and interactive visual solutions.", images = "images/Hauser12VCF.jpg", thumbnails = "images/Hauser12VCF_thumb.jpg", location = "Bergen, Norway", url = "http://www.ii.uib.no/vis/vcf/" } @MISC {Hauser12VisTutorial, author = "Steffen Oeltze and Helmut Doleisch and Helwig Hauser and Gunther Weber", title = "Interactive Visual Analysis of Scientific Data", howpublished = "Tutorial at the IEEE VisWeek 2012", month = "October", year = "2012", abstract = "In a growing number of application areas, a subject or phenomenon is investigated by means of multiple datasets being acquired over time (spatiotemporal), comprising several attributes per data point (multi-variate), stemming from different data sources (multi-modal) or multiple simulation runs (multirun/ensemble). Interactive visual analysis (IVA) comprises concepts and techniques for a user-guided knowledge discovery in such complex data. Through a tight feedback loop of computation, visualization and user interaction, it provides new insight into the data and serves as a vehicle for hypotheses generation or validation. It is often implemented via a multiple coordinated view framework where each view is equipped with interactive drill-down operations for focusing on data features. Two classes of views are integrated: physical views show information in the context of the spatiotemporal observation space while attribute views show relationships between multiple data attributes. The user may drill-down the data by selecting interesting regions of the observation space or attribute ranges leading to a consistent highlighting of this selection in all other views (brushing-and-linking). In this tutorial, we discuss examples for successful applications of IVA to scientific data from various fields: automotive engineering, climate research, biology, and medicine. We base our discussions on a theoretical foundation of IVA which helps the tutorial attendees in transferring the subject matter to their own data and application area. This universally applicable knowledge is complemented in a tutorial part on IVA of very large data which accounts for the tera- and petabytes being generated by simulations and experiments in many areas of science, e.g., physics, astronomy, and climate research. The tutorial further provides an overview of off-the-shelf IVA solutions. It is concluded by a summary of the gained knowledge and a discussion of open problems in IVA of scientific data. The tutorial slides will be available before the conference start date at: www.vismd.de/doku.php?id=teaching_tutorials:start.", images = "images/Hauser12VisTutorial.png", thumbnails = "images/Hauser12VisTutorial_thumb.png", location = "Seattle (WA), USA", url = "http://visweek.org/visweek/2012/tutorial/interactive-visual-analysis-scientific-data", pres = "pdfs/Hauser12VisTutorialPres01.pdf" } @MISC {Hauser12PaVis, author = "Helwig Hauser and Stephen G. Kobourov and Huamin Qu", title = "Proceedings of the 2012 IEEE Pacific Visualization Symposium", howpublished = "Conference proceedings", month = "February-March", year = "2012", images = "images/Helwig12PaVis01.png", thumbnails = "images/Helwig12PaVis01.png", location = "Songdo, Korea", url = "http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=6178307" } @MISC {Brambilla12Geilo, author = "Andrea Brambilla and Armin Pobitzer and Helwig Hauser", title = "Flow Visualization and the SemSeg project", howpublished = "Poster presented at the Sintef winter school 2012", month = "January", year = "2012", pdf = "pdfs/Brambilla12Geilo.pdf", images = "images/Brambilla12Geilo01.png", thumbnails = "images/Brambilla12Geilo01_thumb.png", location = "Geilo, Norway", url = "http://www.sintef.no/Projectweb/eVITA/Winter-Schools/2012/" } @PHDTHESIS {pobitzer12thesis, author = "Armin Pobitzer", title = "Interactive Visual Analysis of Time-dependent Flows: Physics- and Statistics-based Semantics", school = "Department of Informatics, University of Bergen, Norway", year = "2012", month = "Apr", abstract = "With the increasing use of numerical simulations in the fluid mechanics community in recent years flow visualization increasingly gains importance as an advanced analysis tool for the simulation output. Up to now, flow visualization has mainly focused on the extraction and visualization of structures that are defined by their semantic meaning. Examples for such structures are vortices or separation structures between different groups of particles that travel together. In order to deepen our understanding of structures linked to certain flow phenomena, e.g., how and why they appear, evolve, and finally are destroyed, also linking structures to semantic meaning that is not attributed to them by their very definition, is a highly promising research direction to pursue. In this thesis we provide several approaches on how to augment structures stemming from classical flow visualization techniques by additional semantic information originating from new methods based on physics and statistics. In particular, we target separation structures, the linking of structures with a local semantics to global flow phenomena, and minimal representation of particle dynamics in the context of path line attributes.", pdf = "pdfs/pobitzer12thesis.pdf", images = "images/Pobitzer12Physics.png", thumbnails = "images/Pobitzer12Physics_thumb.png", isbn = "978-82-308-2063-6", url = "https://bora.uib.no/handle/1956/5856" } @PHDTHESIS {angelelli12thesis, author = "Paolo Angelelli", title = "Visual Exploration of Human Physiology: Visualizing Perfusion, Blood Flow and Aging", school = "Department of Informatics, University of Bergen, Norway", year = "2012", month = "Apr", abstract = "With the technological advancements in medical imaging, it is nowadayspossible to capture in-vivo information related to different human physiologicalsystems. Such data extends the more traditional anatomical scans,but add size, complexity and heterogeneity. In addition, while anatomydata is defined in three-dimensional space, and 3D graphics techniques canbe used to represent it on the screen, physiology information is often moreabstract, and require tailored solutions to be represented in combinationwith their anatomical context.This thesis presents solutions for visualizing selected aspects in threedomains of physiology: blood flow, perfusion and aging. With respect toblood flow, it includes a technique to enhance the side-by-side visualizationof the tubular flow in vessels. This result is achieved with a methodthat generates straightened visualizations of the flow in its context, whichcan be easily aligned and then related to each other. With respect to perfusion,this thesis includes an interactive visual analysis solution that easeand improve the exploration, segmentation and analysis of perfusion dataacquired using contrast-enhanced ultrasound. This result is achieved byusing a statistical framework to extract enhancement information, and aninteractive, correlation-based approach to classify the tissue based on similarity.Finally, with respect to aging, two solutions to help exploring largedata collections of repeated examinations are presented. In one, interactivevisual analysis methods are employed to explore and analyze cohort studydata, while the other focuses on the guided exploration of repeated ultrasoundexaminations. Demonstration case studies are include to exemplifythe utility of the presented work.", pdf = "pdfs/angelelli12thesis.pdf", images = "images/angelelli12thesis.png", thumbnails = "images/angelelli12thesis_thumb.png", isbn = "978-82-308-2073-5" } @PHDTHESIS {solteszova12thesis, author = "Veronika \v{S}olt{\'e}szov{\'a}", title = "Perception-Augmenting Illumination", school = "Department of Informatics, University of Bergen, Norway", year = "2012", month = "Aug", abstract = "At each stage of the visualization pipeline, the information is impeded by loss or by noise because of imprecise acquisition, storage limitations, and processing. Furthermore, it passes through the complex and not yet well understood pathways in the human visual system and finally to result into a mental image. Due to the noise that impedes the information in the visualization pipeline and the processes in the human visual system, the mental image and the real-world phenomenon do not match. From the aspect of physics, the input of the visual system is confined only to patterns of light. Illumination is therefore essential in 3D visualization for perception of visualized objects. In this thesis, several advancements for advanced volumetric lighting are presented. First, a novel lighting model that supports interactive light source placement and yields a high-quality soft shadowing effect, is proposed. The light transport is represented by conical functions and approximated with an incremental blurring operation of the opacity buffer during front-to-back slicing of the volume. Furthermore, a new perceptuallyfounded model for expressing shadows that gives a full control over the appearance of shadows in terms of color and opacity, is presented. Third, a systematic error in perception of surface slant is modeled. This knowledge is then applied to adjust an existing shading model in a manner that compensates for the error in perception. These new visualization methodologies are linked to the knowledge of perceptual psychology and the craft of illustrators, who experimented with visual-presentation techniques for centuries. The new methodologies are showcased on challenging acoustic modalities such as 3D medical ultrasound and sonar imaging.", pdf = "pdfs/solteszova12thesis.pdf", images = "images/solteszova12thesis.png", thumbnails = "images/solteszova12thesis_thumb.png", isbn = "978-82-308-2118-3" } @BOOK {peikert12topological, author = "Ronald Peikert and Helwig Hauser and Hamish Carr and Raphael Fuchs", title = "Topological Methods in Data Analysis and Visualization II: Theory, Algorithms, and Applications", publisher = "Springer", year = "2012", series = "Mathematics and Visualization", abstract = "When scientists analyze datasets in a search for underlying phenomena, patterns or causal factors, their first step is often an automatic or semi-automatic search for structures in the data. Of these feature-extraction methods, topological ones stand out due to their solid mathematical foundation. Topologically defined structures -as found in scalar, vector and tensor fields- have proven their merit in a wide range of scientific domains, and scientists have found them to be revealing in subjects such as physics, engineering, and medicine. Full of state-of-the-art research and contemporary hot topics in the subject, this volume is a selection of peer-reviewed papers originally presented at the fourth Workshop on Topology-Based Methods in Data Analysis and Visualization, TopoInVis 2011, held in Zurich, Switzerland. The workshop brought together many of the leading lights in the field for a mixture of formal presentations and discussion. One topic currently generating a great deal of interest, and explored in several chapters here, is the search for topological structures in time-dependent flows, and their relationship with Lagrangian coherent structures. Contributors also focus on discrete topologies of scalar and vector fields, and on persistence-based simplification, among other issues of note. The new research results included in this volume relate to all three key areas in data analysis-theory, algorithms and applications.", images = "images/peikert12topological.png", thumbnails = "images/peikert12topological_thumb.png", isbn = "978-3-642-23175-9", url = "http://www.springer.com/mathematics/computational+science+%26+engineering/book/978-3-642-23174-2" } @ARTICLE {Ma12ScientificStorytelling, author = "Kwan-Liu Ma and I. Liao and J. Frazier and H. Hauser and H.-N. Kostis", title = "Scientific Storytelling Using Visualization", journal = "Computer Graphics and Applications, IEEE", year = "2012", volume = "32", number = "1", pages = "12 -19", month = "Jan.--Feb.", abstract = "Scientists frequently tell stories using visualizations of scientific data, in the process of disseminating findings to peers and the general public. However, techniques and methods for effective scientific storytelling have received little attention so far. This article explores how literary and theatrical narrative conventions can inform the design and presentation of visualizations, and discusses the challenges of adapting scientific visualizations for broader audiences. It also summarizes recent workshops' findings on the role of storytelling in visualizations, and presents several examples of successful scientific-storytelling production teams. The conclusion is that scientific storytelling deserves greater support and recognition by the visualization community.", pdf = "pdfs/Ma12ScientificStorytelling.pdf", images = "images/Ma12ScientificStorytelling01.jpg, images/Ma12ScientificStorytelling02.jpg , images/Ma12ScientificStorytelling03.jpg, ../../../_images/CGA--2012-01--Cover.png", thumbnails = "images/Ma12ScientificStorytelling01_thumb.jpg, images/Ma12ScientificStorytelling02_thumb.jpg , images/Ma12ScientificStorytelling03_thumb.jpg, ../../../_images/CGA--2012-01--Cover_thumb.png", keywords = "literary narrative convention;scientific data visualization; scientific storytelling;theatrical narrative convention;data visualisation; natural sciences computing;", doi = "10.1109/MCG.2012.24", url = "http://dx.doi.org/10.1109/MCG.2012.24", issn = "0272-1716" } @MASTERTHESIS {hisdal12thesis, author = "Sondre Langeland Hisdal", title = "Frequency Modulated Shading", school = "Visualization Group, Department of Informatics, University of Bergen", year = "2012", type = "M.Sc. Thesis", month = "Sep", images = "images/hisdal12master.png,", thumbnails = "images/hisdal12master.png," } @ARTICLE {turkay11brushingDimensions, author = "Cagatay Turkay and Peter Filzmoser and Helwig Hauser", title = "Brushing Dimensions -- A Dual Visual Analysis Model for High-dimensional Data", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2011", volume = "17", number = "12", pages = "2591--2599", abstract = "In many application fields, data analysts have to deal with datasets that contain many expressions per item. The effective analysisof such multivariate datasets is dependent on the users ability to understand both the intrinsic dimensionality of the dataset as well as the distribution of the dependent values with respect to the dimensions. In this paper, we propose a visualization model that enables the joint interactive visual analysis of multivariate datasets with respect to their dimensions as well as with respect to the actual data values. We describe a dual setting of visualization and interaction in items space and in dimensions space. The visualization of items is linked to the visualization of dimensions with brushing and focus+context visualization. With this approach, the user is able to jointly study the structure of the dimensions space as well as the distribution of data items with respect to the dimensions. Even though the proposed visualization model is general, we demonstrate its application in the context of a DNA microarray data analysis.", images = "images/turkay11dimensions.png, images/turkay11dimensions3.png, images/turkay11dimensions2.png", thumbnails = "images/turkay11dimensions_thumb.png, images/turkay11dimensions3_thumb.png, images/turkay11dimensions2_thumb.png", event = "IEEE Information Visualization Conference 2011", location = "Providence, RI, USA", url = "http://dx.doi.org/10.1109/TVCG.2011.178" } @ARTICLE {angelelli11ultrasoundStatistics, author = "Paolo Angelelli and Kim Nylund and Odd Helge Gilja and Helwig Hauser", title = "Interactive Visual Analysis of Contrast-enhanced Ultrasound Databased on Small Neighborhood Statistics", journal = "Computers \& Graphics - Special Issue on Visual Computing in Biology and Medicine", year = "2011", volume = "35", number = "2", pages = "218--226", abstract = "Contrast-enhanced ultrasound (CEUS) has recently become an important technology for lesion detection and characterization in cancer diagnosis. CEUS is used to investigate the perfusion kinetics in tissue over time, which relates to tissue vascularization. In this paper we present a pipeline that enables interactive visual exploration and semi-automatic segmentation and classification of CEUS data.For the visual analysis of this challenging data, with characteristic noise patterns and residual movements, we propose a robust method to derive expressive enhancement measures from small spatio-temporal neighborhoods. We use this information in a stagedvisual analysis pipeline that leads from a more local investigation to global results such as the delineation of anatomic regions according to their perfusion properties. To make the visual exploration interactive, we have developed an accelerated frameworkbased on the OpenCL library, that exploits modern many-cores hardware. Using our application, we were able to analyze datasets from CEUS liver examinations, being able to identify several focal liver lesions, segment and analyze them quickly and precisely, and eventually characterize them.", pdf = "pdfs/angelelli11CEUSIVA.pdf", vid = "vids/angelelli11CEUSSegmentation.wmv", images = "images/angelelli11ultrasoundStatistics2.jpg, images/angelelli11ultrasoundStatistics1.jpg", thumbnails = "images/angelelli11ultrasoundStatistics2_thumb.jpg, images/angelelli11ultrasoundStatistics1_thumb.jpg", url = "http://dx.doi.org/10.1016/j.cag.2010.12.005", project = "illustrasound,medviz,illvis" } @ARTICLE {turkay11temporalCluster, author = "Cagatay Turkay and Julius Parulek and Nathalie Reuter and Helwig Hauser", title = "Interactive Visual Analysis of Temporal Cluster Structures", journal = "Computer Graphics Forum", year = "2011", volume = "30", number = "3", pages = "711--720", abstract = "Cluster analysis is a useful method which reveals underlying structures and relations of items after grouping them into clusters. In the case of temporal data, clusters are defined over time intervals where they usually exhibit structural changes. Conventional cluster analysis does not provide sufficient methods to analyze these structural changes, which are, however, crucial in the interpretation and evaluation of temporal clusters. In this paper, we present two novel and interactive visualization techniques that enable users to explore and interpret the structural changes of temporal clusters. We introduce the temporal cluster view, which visualizes the structural quality of a number of temporal clusters, and temporal signatures, which represents the structure of clusters over time. We discuss how these views are utilized to understand the temporal evolution of clusters. We evaluate the proposedtechniques in the cluster analysis of mixed lipid bilayers.", images = "images/turkay11temporal1.jpg, images/turkay11temporal2.jpg, images/turkay11temporal3.jpg", thumbnails = "images/turkay11temporal1_thumb.jpg, images/turkay11temporal2_thumb.jpg, images/turkay11temporal3_thumb.jpg", url = "http://dx.doi.org/10.1111/j.1467-8659.2011.01920.x", event = "EuroVis 2011", location = "Bergen, Norway" } @ARTICLE {lampe11curveDensity, author = "Ove Daae Lampe and Helwig Hauser", title = "Curve Density Estimates", journal = "Computer Graphics Forum", year = "2011", volume = "30", number = "3", pages = "633--642", abstract = "In this work, we present a technique based on kernel density estimation for rendering smooth curves. With this approach, we produce uncluttered and expressive pictures, revealing frequency information about one, or, multiple curves, independent of the level of detail in the data, the zoom level, and the screen resolution. With this technique the visual representation scales seamlessly from an exact line drawing, (for low-frequency/low-complexity curves) to a probability density estimate for more intricate situations. This scale-independence facilitates displays based on non-linear time, enabling high-resolution accuracy of recent values, accompanied by long historical series forcontext. We demonstrate the functionality of this approach in the context of prediction scenarios and in the context of streaming data.", images = "images/lampe11curveDensity3.jpg, images/lampe11curveDensity1.jpg, images/lampe11curveDensity2.jpg", thumbnails = "images/lampe11curveDensity3_thumb.jpg, images/lampe11curveDensity1_thumb.jpg, images/lampe11curveDensity2_thumb.jpg", url = "http://dx.doi.org/10.1111/j.1467-8659.2011.01912.x", event = "EuroVis 2011", location = "Bergen, Norway", project = "elad" } @ARTICLE {kehrer11heterogeneous, author = "Johannes Kehrer and Philipp Muigg and Helmut Doleisch and Helwig Hauser", title = "Interactive Visual Analysis of Heterogeneous Scientific Data across an Interface", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2011", volume = "17", number = "7", pages = "934--946", abstract = "We present a systematic approach to the interactive visual analysis of heterogeneous scientific data. The data consists of two interrelated parts given on spatial grids over time (e.g., atmosphere and ocean part from a coupled climate model). By integrating both data parts in a framework of coordinated multiple views (with linking and brushing), the joint investigation of features across the data parts is enabled. An interface is constructed between the data parts that specifies (a) which grid cells in one part are related to grid cells in the other part, and vice versa, (b) how selections (in terms of feature extraction via brushing) are transferred between the two parts, and (c) how an update mechanism keeps the feature specification in both data parts consistentduring the analysis. We also propose strategies for visual analysis that result in an iterative refinement of features specified across both data parts. Our approach is demonstrated in the context of a complex simulation of fluid--structure interaction and a multi-run climate simulation.", pdf = "pdfs/kehrer11heterogeneous.pdf", vid = "vids/kehrer11heterogeneous.html", images = "images/kehrer11heterogeneous2.jpg, images/kehrer11heterogeneous3.jpg, images/kehrer11heterogeneous0.jpg, images/kehrer11heterogeneous1.jpg", thumbnails = "images/kehrer11heterogeneous2_thumb.jpg, images/kehrer11heterogeneous3_thumb.jpg, images/kehrer11heterogeneous0_thumb.jpg, images/kehrer11heterogeneous1_thumb.jpg", event = "IEEE VisWeek 2011", location = "Providence, RI, USA", url = "http://dx.doi.org/10.1109/TVCG.2010.111" } @INCOLLECTION {oye11illustrativeCouinaud, author = "Ola Kristoffer {\O }ye and Dag Magne Ulvang and Odd Helge Gilja and Helwig Hauser and Ivan Viola", title = "Illustrative Couinaud Segmentation for Ultrasound Liver Examinations", booktitle = "Smart Graphics", publisher = "Springer Berlin / Heidelberg", year = "2011", volume = "6815", series = "Lecture Notes in Computer Science", pages = "60--77", abstract = "Couinaud segmentation is a widely used liver partitioning scheme for describing the spatial relation between diagnostically relevant anatomical and pathological features in the liver. In this paper, we propose a new methodologyfor effectively conveying these spatial relations during the ultrasound examinations. We visualize the two-dimensional ultrasound slice in the context of a three-dimensional Couinaud partitioning of the liver. The partitioning is described by planes in 3D reflecting the vascular tree anatomy, specified in the patient by the examiner using her natural interaction tool, i.e., the ultrasound transducer with positional tracking. A pre-defined generic liver model is adapted to the specified partitioning in order to provide a representation of the patients liver parenchyma. The specified Couinaud partitioning and parenchyma model approximation is then used to enhance the examination by providing visual aids to convey the relationships between the placement of the ultrasound plane and the partitioned liver. The 2D ultrasound slice is augmented with Couinaud partitioning intersection information and dynamic label placement. A linked 3D view shows the ultrasound slice, cutting the liver and displayed using fast exploded view rendering. The described visual augmentation has been characterized by the clinical personnel as very supportive during the examination procedure, and also as a good basis for pre-operative case discussions.", images = "images/oye11illustrativeCouinaud1.jpg, images/oye11illustrativeCouinaud2.jpg, images/oye11illustrativeCouinaud3.jpg", thumbnails = "images/oye11illustrativeCouinaud1_thumb.jpg, images/oye11illustrativeCouinaud2_thumb.jpg, images/oye11illustrativeCouinaud3_thumb.jpg", isbn = "978-3-642-22570-3", url = "http://dx.doi.org/10.1007/978-3-642-22571-0_6", project = "illustrasound,medviz,illvis" } @ARTICLE {pobitzer11topology, author = "Armin Pobitzer and Ronald Peikert and Raphael Fuchs and Benjamin Schindler and Alexander Kuhn and Holger Theisel and Kresimir Matkovic and Helwig Hauser", title = "The State of the Art in Topology-based Visualization of Unsteady Flow", journal = "Computer Graphics Forum", year = "2011", volume = "30", number = "6", pages = "1789--1811", month = "September", abstract = "Vector fields are a common concept for the representation of many different kinds of flow phenomena in science and engineering. Methods based on vector field topology are known for their convenience for visualizing and analyzing steady flows, but a counterpart for unsteady flows is still missing. However, a lot of good and relevant work aiming at such a solution is available.We give an overview of previous research leading towards topology-based and topology-inspired visualization of unsteady flow, pointing out the different approaches and methodologies involved as well as their relation to each other, taking classical (i.e., steady) vector field topology as our starting point. Particularly, we focus on Lagrangian methods, space-time domain approaches, local methods, and stochastic and multi-field approaches. Furthermore, we illustrate our review with practical examples for the different approaches.", images = "images/pobitzer10topology.jpg,", thumbnails = "images/pobitzer10topology_thumb.jpg", project = "semseg", url = "http://dx.doi.org/10.1111/j.1467-8659.2011.01901.x" } @ARTICLE {ruiz11automaticTFs, author = "Marc Ruiz and Anton Bardera and Imma Boada and Ivan Viola and Miquel Feixas and Mateu Sbert", title = "Automatic Transfer Functions based on Informational Divergence", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2011", volume = "17", number = "12", pages = "1932--1941", abstract = "In this paper we present a framework to define transfer functions from a target distribution provided by the user. A targetdistribution can reflect the data importance, or highly relevant data value interval, or spatial segmentation. Our approach is basedon a communication channel between a set of viewpoints and a set of bins of a volume data set, and it supports 1D as well as 2D transfer functions including the gradient information. The transfer functions are obtained by minimizing the informational divergence or Kullback-Leibler distance between the visibility distribution captured by the viewpoints and a target distribution selected by the user. The use of the derivative of the informational divergence allows for a fast optimization process. Different target distributions for 1D and 2D transfer functions are analyzed together with importance-driven and view-based techniques.", images = "images/ruiz11automaticTFs1.jpg, images/ruiz11automaticTFs2.jpg, images/ruiz11automaticTFs3.jpg, images/ruiz11automaticTFs4.jpg", thumbnails = "images/ruiz11automaticTFs1_thumb.jpg, images/ruiz11automaticTFs2_thumb.jpg, images/ruiz11automaticTFs3_thumb.jpg, images/ruiz11automaticTFs4_thumb.jpg", event = "IEEE Visualization Conference 2011", location = "Providence, RI, USA", project = "illustrasound" } @ARTICLE {angelelli11straightening, author = "Paolo Angelelli and Helwig Hauser", title = "Straightening Tubular Flow for Side-by-Side Visualization", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2011", volume = "17", number = "12", pages = "2063--2070", abstract = "Flows through tubular structures are common in many fields, including blood flow in medicine and tubular fluid flows in engineering.The analysis of such flows is often done with a strong reference to the main flow direction along the tubular boundary. In this paper we present an approach for straightening the visualization of tubular flow. By aligning the main reference direction of the flow, i.e., the center lineof the bounding tubular structure, with one axis of the screen, we are able to natively juxtapose (1.) different visualizations of the same flow,either utilizing different flow visualization techniques, or by varying parameters of a chosen approach such as the choice of seeding locationsfor integration-based flow visualization, (2.) the different time steps of a time-dependent flow, (3.) different projections around the center line, and (4.) quantitative flow visualizations in immediate spatial relation to the more qualitative classical flow visualization. We describe how to utilize this approach for an informative interactive visual analysis. We demonstrate the potential of our approach by visualizing two datasets from two different fields: an arterial blood flow measurement and a tubular gas flow simulation from the automotive industry.", pdf = "pdfs/angelelli11straightening.pdf", vid = "vids/angelelli11TubularFlowStraightening.wmv", images = "images/angelelli11straightening1.jpg, images/angelelli11straightening2.jpg", thumbnails = "images/angelelli11straightening1_thumb.jpg, images/angelelli11straightening2_thumb.jpg", event = "IEEE Visualization Conference 2011", location = "Providence, RI, USA", url = "http://dx.doi.org/10.1109/TVCG.2011.235" } @ARTICLE {pobitzer11energyScale, author = "Armin Pobitzer and Murat Tutkun and {\O }yvind Andreassen and Raphael Fuchs and Ronald Peikert and Helwig Hauser", title = "Energy-scale Aware Feature Extraction for Flow Visualization", journal = "Computer Graphics Forum", year = "2011", volume = "30", number = "3", pages = "771--780", abstract = "In the visualization of flow simulation data, feature detectors often tend to result in overly rich response, making some sort of filtering or simplification necessary to convey meaningful images. In this paper we present an approach that builds upon a decomposition of the flow field according to dynamical importance of different scales of motion energy. Focusing on the high-energy scales leads to a reduction of the flow field while retaining the underlying physical process. The presented method acknowledges the intrinsic structures of the flow according to its energy and therefore allows to focus on the energetically most interesting aspects of the flow. Our analysis shows that this approach can be used for methods based on both local feature extraction and particle integration and we provide a discussion of the error caused by the approximation. Finally, we illustrate the use of the proposed approach for both a local and a global feature detector and in the context of numerical flow simulations.", images = "images/pobitzer11energyScale1.jpg, images/pobitzer11energyScale3.jpg, images/pobitzer11energyScale2.jpg", thumbnails = "images/pobitzer11energyScale1_thumb.jpg, images/pobitzer11energyScale3_thumb.jpg, images/pobitzer11energyScale2_thumb.jpg", url = "http://dx.doi.org/10.1111/j.1467-8659.2011.01926.x", event = "EuroVis 2011", location = "Bergen, Norway", project = "semseg" } @ARTICLE {Matkovic11CurrentTrends, author = "Kresimir Matkovic and Alan Lez and Helwig Hauser and Armin Pobitzer and Holger Theisel and Alexander Kuhn and Mathias Otto and Ronald Peikert and Benjamin Schindler and Raphael Fuchs", title = "Current Trends for 4D Space-Time Topology for Semantic Flow Segmentation", journal = "Procedia Computer Science", year = "2011", volume = "7", number = "0", pages = "253--255", abstract = "Recent advances in computing and simulation technology promote the simulation of time-dependent flows, i.e., flows where the velocity field changes over time. The simulation of time-dependent flow is a more realistic approximation of natural phenomena and it represents an invaluable tool for scientists and practitioners in multiple disciplines, including meteorology, vehicle design, and medicine. Flow visualization, a subfield of scientific visualization, is one of several research areas which deal with the analysis of flows. There are many methods for the analysis of steady flows, but the extension to the time-dependent case is not straight forward. The SemSeg project, a FET-Open project in the 7th Framework programme, attempts to provide a solution for the semantic segmentation of time-dependent flows. It aims at the formulation of a sound theoretical mechanism to describe structural features in time-dependent flow. In this paper, we briefly summarize recent research results from the SemSeg project. Several different approaches are pursued in the project, including methods based on the finite-time Lyapunov exponent (FTLE), methods based on vector field topology (VFT), and interactive visual analysis (IVA) methods. Uncertainty visualization and the interactive evaluation of methods are helping in evaluating the results.", images = "images/Matkovic11CurrentTrends.png", thumbnails = "images/Matkovic11CurrentTrends_thumb.png", note = "Proceedings of the 2nd European Future Technologies Conference and Exhibition 2011 (FET 11)", issn = "1877-0509", doi = "10.1016/j.procs.2011.09.013", url = "http://www.sciencedirect.com/science/article/pii/S1877050911005734" } @ARTICLE {Matkovic11InteractiveVisual, author = "Kresimir Matkovic and Denis Gracanin and Mario Jelovic and Helwig Hauser", title = "Interactive Visual Analysis Supporting Design, Tuning, and Optimization of Diesel Engine Injection", journal = "Proceedings of IEEE Visualization 2011 (Discovery Exhibition)", year = "2011", abstract = "Design and optimization of modern, complex systems is unimaginable without simulation. Although the design goals are known in advance, finding an optimal combination of input parameters is a long and tedious task. Simulation of car engine injection systems is a relatively short process. It is possible to run many simulations and then to explore the parameter space. Efficient tools and techniques for parameter space exploration and optimization are needed. We have developed an interactive visual analysis tool, ComVis, and related techniques. We illustrate how ComVis is used to explore the parameter space and to tune and optimize car engine injection systems. The collaboration between domain experts and visualization experts resulted in a new workflow for injection system design, and in development of new, commercially available tools.", images = "images/Matkovic11InteractiveVisual01.png, Matkovic11InteractiveVisual02.png, Matkovic11InteractiveVisual03.png", thumbnails = "images/Matkovic11InteractiveVisual_thumb.png", url = "http://www.discoveryexhibition.org/pmwiki.php/Entries/2011Matkovic" } @MISC {Lueks11Spatially, author = "Wouter Lueks and Ivan Viola and Matthew van der Zwan and Henk Bekker and Tobias Isenberg", title = "Spatially Continuous Change of Abstraction in Molecular Visualization", howpublished = "BioVis 2011 - Abstract track", year = "2011", abstract = "Based on an approach for the temporal change of abstraction in molecular visualization we describe how to achieve a spatially explicit control of abstraction. This allows us to depict different abstraction stages of a single molecule in a single still-image visualization. This approach works best for long, linear molecules with repeating substructures that allow viewers to visually compare the continuous representational changes of these parts.", images = "images/Lueks11Spatially01.jpg, images/Lueks11Spatially02.jpg, images/Lueks11Spatially03.jpg", thumbnails = "images/Lueks11Spatially01_thumb.jpg, images/Lueks11Spatially02_thumb.jpg, images/Lueks11Spatially03_thumb.jpg", youtube = "https://www.youtube.com/watch?v=1ANKp9mMFvo", location = "Providence, RI", url = "http://www.cs.rug.nl/~isenberg/VideosAndDemos/Zwan2011IMV", notes = "Best Abstract award" } @PHDTHESIS {lampe11thesis, author = "Ove Daae Lampe", title = "Interactive Visual Analysis of Process Data", school = "Department of Informatics, University of Bergen, Norway", year = "2011", month = "Sep", abstract = "Data gathered from processes, or process data, contains many different aspectsthat a visualization system should also convey. Aspects such as, temporalcoherence, spatial connectivity, streaming data, and the need for in-situvisualizations, which all come with their independent challenges. Additionally,as sensors get more affordable, and the benefits of measurements get clearer weare faced with a deluge of data, of which sizes are rapidly growing. With allthe aspects that should be supported and the vast increase in the amount ofdata, the traditional techniques of dashboards showing the recent data becomesinsufficient for practical use. In this thesis we investigate how to extend the traditionalprocess visualization techniques by bringing the streaming process datainto an interactive visual analysis setting. The augmentation of process visualizationwith interactivity enables the users to go beyond the mere observation,pose questions about observed phenomena and delve into the data to mine forthe answers. Furthermore, this thesis investigates how to utilize frequency based,as opposed to item based, techniques to show such large amounts of data. Byutilizing Kernel Density Estimates (KDE) we show how the display of streamingdata benefit by the non-parametric automatic aggregation to interpret incomingdata put in context to historic data.", pdf = "pdfs/lampe11thesis.pdf", images = "images/lampe11thesis.png", thumbnails = "images/lampe11thesis_thumb.png", isbn = "978-82-308-1910-4" } @MISC {Hauser2011Dagstuhl, author = "Helwig Hauser", title = "Helwig Hauser on Interactive Visual Analysis of Multi-Dimensional Scientific Data", howpublished = "Invited talk at the Dagstuhl Seminar on Scientific Visualization in Dagstuhl, Germany.", month = "June", year = "2011", abstract = "Invited talk at the Dagstuhl Seminar on Scientific Visualization in Dagstuhl, Germany.", pdf = "pdfs/2011-06-06--Dagstuhl--MultiDimSciDataIVA--print--new--2up.pdf", images = "images/2011-06-06--Dagstuhl--MultiDimSciDataIVA--print--new--2up_Image_0001.jpg, images/2011-06-06--Dagstuhl--MultiDimSciDataIVA--print--new--2up_Image_0002.jpg, images/2011-06-06--Dagstuhl--MultiDimSciDataIVA--print--new--2up_Image_0002(2).jpg, images/2011-06-06--Dagstuhl--MultiDimSciDataIVA--print--new--2up_Image_0004.jpg", thumbnails = "images/2011-06-06--Dagstuhl--MultiDimSciDataIVA--print--new--2up_Image_0001(2).jpg" } @MISC {viola11passingThrough, author = "Ivan Viola", title = "Passing Through the Trough of Disillusionment of Illustrative Visualization", howpublished = "Keynote at EG-UK Theory and Practice of Computer Graphics Conference (TP.CG.2011)", month = "September", year = "2011", abstract = "Efficient illustration craft is a vast source of inspiration for development of new visual abstractions in data visualization. Many new illustration-inspired techniques have emerged up to now, primarily arguing their validity with a statement like: \"The illustrators have been using this technique for centuries and therefore we adapt their technique for interactive data display...\" Argumentation of such kind was stimulating in the initial phase of illustrative visualization research, but nowadays this reasoning is no longer satisfactory. It is becoming apparent that ad-hoc adaptation can have arbitrary outcome. A systematic adaptation requires a vivid dialog with illustrators and a well-founded reasoning by means of the vision and cognitive sciences. This talk will assess the efficiency of selected visual abstractions, adapted for interactive visualization, in terms of their consistency with established perceptual principles.", vid = "https://picasaweb.google.com/viola.ivan/Talks#5651394119519056546", images = "images/viola11passingThrough.jpg", thumbnails = "images/viola11passingThrough_thumb.jpg", location = "Warwick, UK", pres = "pdfs/viola11passingThrough.pdf" } @MASTERTHESIS {Waage11thesis, author = "Jonas Waage", title = "Visually controlled on-demand Derivation and Visualization of Perfusion Parameters", school = "Visualization Group, Department of Informatics, University of Bergen", year = "2011", type = "MSc. thesis", month = "aug", images = "images/P042_I001.jpg,images/P061_I001.jpg,images/P061_I002.jpg,images/P062_I001.jpg,images/P063_I001.jpg,", thumbnails = "images/P042_I001.jpg,images/P061_I001.jpg,images/P061_I002.jpg,images/P062_I001.jpg,images/P063_I001.jpg," } @PHDTHESIS {kehrer11thesis, author = "Johannes Kehrer", title = "Interactive Visual Analysis of Multi-faceted Scientific Data", school = "Department of Informatics, University of Bergen, Norway", year = "2011", month = "Mar", abstract = "Visualization plays an important role in exploring, analyzingand presenting large and heterogeneous scientific data that arise in many disciplines of medicine, research, engineering, and others. We can see that model and data scenarios are becoming increasingly multi-faceted: data are often multi-variate and time-dependent, they stem from different data sources (multi-modal data), from multiple simulation runs (multi-run data), or from multi-physics simulations of interacting phenomena that consist of coupled simulation models (multi-model data). The different data characteristics result in special challenges for visualization research and interactive visual analysis. The data are usually large and come on various types of grids with different resolution that need to be fused in the visual analysis.This thesis deals with different aspects of the interactive visual analysis of multi-faceted scientific data. The main contributions of this thesis are: 1) a number of novel approaches and strategies for the interactive visual analysis of multi-run data; 2) a concept that enables the feature-based visual analysis across an interface between interrelated parts of heterogeneous scientific data (including data from multi-run and multi-physics simulations); 3) a model for visual analysis that is based on the computation of traditionaland robust estimates of statistical moments from higher-dimensional multi-run data; 4) procedures for visual exploration of time-dependent climate data that support the rapid generation of promising hypotheses, which are subsequently evaluated with statistics; and 5) structured design guidelines for glyph-based 3D visualization of multi-variate data together with a novel glyph. All these approaches are incorporated in a single framework for interactive visual analysis that uses powerful concepts such as coordinated multiple views, feature specification via brushing, and focus+context visualization. Especially the data derivation mechanism of the framework has proven to be very useful for analyzing different aspects of the data at different stages of the visual analysis. The proposed concepts and methods are demonstrated in a number of case studies that are based on multi-run climate data and data from a multi-physics simulation.", pdf = "pdfs/kehrer11thesis.pdf", images = "images/kehrer11thesis.jpg, images/kehrer11heterogeneous1.jpg, images/kehrer08vis01.jpg, images/kehrer11thesis1.png", thumbnails = "images/kehrer11thesis_thumb.jpg, images/kehrer11heterogeneous1_thumb.jpg, images/kehrer08vis01_thumb.jpg, images/kehrer11thesis1_thumb.png", url = "http://www.ii.UiB.no/vis/team/kehrer/thesis/", isbn = "978-82-308-1733-9" } @ARTICLE {viola10editorial, author = "Ivan Viola and Helwig Hauser and David Ebert", title = "Editorial note for special section on illustrative visualization", journal = "Computers \& Graphics", year = "2010", volume = "34", number = "4", pages = "335--336", images = "images/viola10editorial.jpg", thumbnails = "images/viola10editorial_thumb.jpg", url = "http://dx.doi.org/10.1016/j.cag.2010.05.011", project = "illvis" } @MISC {hauser10levelsOfComplexity, author = "Helwig Hauser", title = "Interactive Visual Analysis with different levels of complexity", howpublished = "Invited talk at TU Delft", month = "June 24", year = "2010", abstract = "Interactive visual data exploration and analysis is a powerful methodology for enabling insight into complex and also large data. The iterative process of visualization and interaction (and back to visualization, aso.) can be seen as a visual dialog between the user and the data. Thereby, powerful data analysis schemes are enabled such as a step-by-step information drill-down, steered by the users perception, cognition, and knowledge. In this talk, we look at different levels of this methodology (in the sense of levels of complexity), starting at the first level of ``show \& brush'' continuing then via ``relational analysis'' to a third level that we call ``complex analysis.'' The hypothesis is stated that it indeed is useful to have these different levels of complexity for interactive visual data analysis: a large share of all addressed problems can be satisfyingly solved with the ``simple'' level of ``show \& brush,'' while the more complex levels of this methodology are only paying off in special cases. Along with a characterization of these levels, we also take a look at a number of illustrative examples.", images = "images/hauser10levelsOfComplexity.jpg", thumbnails = "images/hauser10levelsOfComplexity_thumb.png", location = "Delft, The Netherlands", pres = "pdfs/hauser10levelsOfComplexity-pres.pdf" } @MISC {hauser10interactiveStoryTelling, author = "Helwig Hauser", title = "Interactive Story Telling for Presentation with Visualization", howpublished = "Talk at CMR Forum", month = "December 17", year = "2010", images = "images/hauser10interactiveStoryTelling.png", thumbnails = "images/hauser10interactiveStoryTelling_thumb.jpg", location = "Christian Michelsen Research, Bergen, www.CMR.no", pres = "pdfs/hauser10interactiveStoryTelling.pdf" } @ARTICLE {ladstaedter10explorationClimateData, author = "Florian Ladst{\"a}dter and Andrea K. Steiner and Bettina C. Lackner and Barbara Pirscher and Gottfried Kirchengast and Johannes Kehrer and Helwig Hauser and Philipp Muigg and Helmut Doleisch", title = "Exploration of Climate Data Using Interactive Visualization", journal = "Journal of Atmospheric and Oceanic Technology", year = "2010", volume = "27", number = "4", pages = "667--679", month = "April", abstract = "In atmospheric and climate research, the increasing amount of data available from climate models and observations provides new challenges for data analysis. We present interactive visual exploration as an innovative approach to handle large datasets. Visual exploration does not require any previous knowledge about the data as is usually the case with classical statistics. It facilitatesiterative and interactive browsing of the parameter space in order to quickly understand the data characteristics, to identify deficiencies, to easily focus on interesting features, and to come up with new hypotheses about the data. These properties extend the common statistical treatment of data, and provide a fundamentally different approach. We demonstrate the potential of this technology by exploring atmospheric climate data from different sources including reanalysis datasets, climate models, and radio occultation satellite data. Results are compared to those from classical statistics revealing the complementary advantages of visual exploration. Combining both, the analytical precision of classical statistics and the holistic power of interactive visual exploration, the usual work flow of studying climate data can be enhanced.", images = "images/ladstaedter10exploration.jpg, images/ladstaedter10exploration1.jpg, images/ladstaedter10exploration3.jpg, images/ladstaedter10exploration2.jpg", thumbnails = "images/ladstaedter10exploration_thumb.jpg, images/ladstaedter10exploration1_thumb.jpg, images/ladstaedter10exploration3_thumb.jpg, images/ladstaedter10exploration2_thumb.jpg", url = "http://dx.doi.org/10.1175/2009JTECHA1374.1" } @ARTICLE {fuchs10lagrangian, author = "Raphael Fuchs and Jan Kemmler and Benjamin Schindler and Jrgen Waser and Filip Sadlo and Helwig Hauser and Ronald Peikert", title = "Toward a Lagrangian Vector Field Topology", journal = "Computer Graphics Forum", year = "2010", volume = "29", number = "3", pages = "1163--1172", month = "june", abstract = "In this paper we present an extended critical point concept which allows us to apply vector field topology in the case of unsteady flow. We propose a measure for unsteadiness which describes the rate of change of the velocities ina fluid element over time. This measure allows us to select particles for which topological properties remain intact inside a finite spatio-temporal neighborhood. One benefit of this approach is that the classification of critical points based on the eigenvalues of the Jacobian remains meaningful. In the steady case the proposed criterion reduces to the classical definition of critical points. As a first step we show that finding an optimal Galilean frame of reference can be obtained implicitly by analyzing the acceleration field. In a second step we show that this can be extended by switching to the Lagrangian frame of reference. This way the criterion can detect critical points moving along intricate trajectories. We analyze the behavior of the proposed criterion based on two analytical vector fields for which a correct solution is defined by their inherent symmetries and present results for numerical vector fields.", images = "images/fuchs10lagrangian2.jpg, images/fuchs10lagrangian.jpg", thumbnails = "images/fuchs10lagrangian2_thumb.jpg, images/fuchs10lagrangian_thumb.jpg", event = "EuroVis 2010", location = "Bordeaux, France", url = "http://dx.doi.org/10.1111/j.1467-8659.2009.01686.x", project = "semseg" } @ARTICLE {solteszova10multidirectional, author = "Veronika \v{S}olt{\'e}szov{\'a} and Daniel Patel and Stefan Bruckner and Ivan Viola", title = "A Multidirectional Occlusion Shading Model for Direct Volume Rendering", journal = "Computer Graphics Forum", year = "2010", volume = "29", number = "3", pages = "883--891", month = "june", abstract = "In this paper, we present a novel technique which simulates directional light-scattering for more realistic interactive visualization of volume data. Our method extends the recent directional occlusion shading model by enabling light-source positioning with practically no performance penalty. Light transport is approximated using a tilted cone-shaped functionwhich leaves elliptic footprints in the opacity buffer during slice-based volume rendering. We perform an incremental blurring operation on the opacity buffer for each slice in front-to-back order. This buffer is then used to define the degree of occlusion for the subsequent slice. Our method is capable of generating high-quality soft shadowing effects, allows interactive modification of all illumination and rendering parameters, and requires no pre-computation.", vid = "vids/solteszova10multi.html", images = "images/solteszova10multi.jpg, images/solteszova10multi1.jpg, images/solteszova10multi2.jpg, images/solteszova10multi3.jpg", thumbnails = "images/solteszova10multi_thumb.jpg, images/solteszova10multi1_thumb.jpg, images/solteszova10multi2_thumb.jpg, images/solteszova10multi3_thumb.jpg", event = "EuroVis 2010", location = "Bordeaux, France", url = "http://dx.doi.org/10.1111/j.1467-8659.2009.01695.x", project = "illustrasound,medviz,illvis" } @ARTICLE {kehrer10moments, author = "Johannes Kehrer and Peter Filzmoser and Helwig Hauser", title = "Brushing Moments in Interactive Visual Analysis", journal = "Computer Graphics Forum", year = "2010", volume = "29", number = "3", pages = "813--822", month = "june", abstract = "We present a systematic study of opportunities for the interactive visual analysis of multi-dimensional scientific data. This is based on the integration of statistical aggregations along selected data dimensions in a framework of coordinated multiple views (with linking and brushing). Traditional and robust estimates of the four statistical moments (mean, variance, skewness, and kurtosis) as well as measures of outlyingness are integrated in an iterative visual analysis process. Brushing particular statistics, the analyst can investigate data characteristics such as trends and outliers. We present a categorization of beneficial combinations of attributes in 2D scatterplots: (a) k-th vs. (k+1)-th statistical moment of a traditional or robust estimate, (b) traditional vs. robust version of the same moment, (c) two different robust estimates of the same moment. We propose selected view transformations to iteratively construct this multitude of informative views as well as to enhance the depiction of the statistical properties in the scatterplots. In the framework, we interrelate the original distributional data and the aggregated statistics, which allows the analyst to work with both data representations simultaneously. We demonstrate our approach in the context of two visual analysis scenarios of multi-run climate simulations.", vid = "vids/kehrer10moments.html", images = "images/kehrer10moments.jpg, images/kehrer10moments1.jpg, images/kehrer10moments2.jpg", thumbnails = "images/kehrer10moments_thumb.jpg, images/kehrer10moments1_thumb.jpg, images/kehrer10moments2_thumb.jpg", event = "EuroVis 2010", location = "Bordeaux, France", pres = "pdfs/kehrer10moments-presentation.pdf", url = "http://dx.doi.org/10.1111/j.1467-8659.2009.01697.x" } @MISC {hauser10storyTelling, author = "Helwig Hauser", title = "Story Telling for Visualization", howpublished = "Talk at Story Telling workshop 2010, UC Davis", month = "November 1", year = "2010", images = "images/hauser10storyTelling.png", thumbnails = "images/hauser10storyTelling_thumb.jpg", location = "Davis, CA", pres = "pdfs/hauser10storyTelling.pdf" } @ARTICLE {bruckner10HVC, author = "Stefan Bruckner and Peter Rautek and Ivan Viola and Mike Roberts and Mario Costa Sousa and Meister Eduard Gr{\"o}ller", title = "Hybrid Visibility Compositing and Masking for Illustrative Rendering", journal = "Computers \& Graphics - Special Issue on Illustrative Visualization", year = "2010", volume = "34", number = "4", pages = "361--369", abstract = "In this paper, we introduce a novel framework for thecompositing of interactively rendered 3D layers tailored to the needs of scientific illustration. Currently, traditional scientific illustrations are produced in a series of composition stages, combining different pictorial elements using 2D digital layering. Our approach extends the layer metaphor into 3D without giving up the advantages of 2D methods. The new compositing approach allows for effects such as selective transparency, occlusion overrides, and soft depth buffering. Furthermore, we show how common manipulation techniques such as masking can be integrated into this concept. These tools behave just like in 2D, but their influence extends beyond a single viewpoint. Since the presented approach makes no assumptions about the underlying rendering algorithms, layers can be generated based on polygonal geometry, volumetric data, point-based representations, or others. Our implementation exploitscurrent graphics hardware and permits real-time interactionand rendering.", images = "images/bruckner10hvc.jpg, images/bruckner10hvc2.jpg", thumbnails = "images/bruckner10hvc_thumb.jpg, images/bruckner10hvc2-thumb.jpg", url = "http://dx.doi.org/10.1016/j.cag.2010.04.003", project = "illustrasound,medviz,illvis" } @ARTICLE {matkovic10modelView, author = "Kresimir Matkovic and Denis Gracanin and Mario Jelovic and Andreas Ammer and Alan Lez and Helwig Hauser", title = "Interactive Visual Analysis of Multiple Simulation Runs using the Simulation Model View: Understanding and Tuning of an Electronic Unit Injector", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2010", volume = "16", number = "6", pages = "1449--1457 ", abstract = "Multiple simulation runs using the same simulation model with different values of control parameters usually generate large data sets that capture the variational aspects of the behavior of the modeled and simulated phenomenon. We have identified a conceptual and visual gap between the simulation model behavior and the data set that makes data analysis more difficult thannecessary. We propose a simulation model view that helps to bridge that gap by visually combining the simulation model description and the generated data. The simulation model view provides a visual outline of the simulation process and the corresponding simulation model. The view is integrated in a Coordinated Multiple Views (CMV) system. We use three levels of details to efficiently use the display area provided by the simulation model view. We collaborated with a domain expert and used the simulation model view on a problem in the automotive application domain, i.e., meeting the emission requirements for Diesel engines. One of the key components is a fuel injector unit so our goal was to understand and tune an electronic unit injector (EUI). We were mainly interested in understanding the model and how to tune it for three different operation modes: low emission, low consumption, and high power. Very positive feedback from the domain expert shows that the use of the simulation model view and the corresponding analysis procedures within a CMV system amount to an effective technique for interactive visual analysis of multiple simulation runs. We also developed new analysis procedures based on these results.", images = "images/matkovic10model1.jpg, images/matkovic10model2.jpg, images/matkovic10model3.jpg", thumbnails = "images/matkovic10model1_thumb.jpg, images/matkovic10model2_thumb.jpg, images/matkovic10model3_thumb.jpg", event = "IEEE Visualization 2010", location = "Salt Lake City, US", url = "http://dx.doi.org/10.1109/TVCG.2010.171" } @MISC {hauser10brainPerfusion, author = "Helwig Hauser and Sylvia Gla\ßer", title = "Visualizing Statistics of Brain Perfusion Data", howpublished = "Talk in the MedViz Seminar Series", month = "October 8", year = "2010", abstract = "Following up earlier cooperative research work with the University of Magdeburg in Germany (with Steffen Oeltze et al.), we are pursuing a new study of perfusion data (this time with Sylvia Glasser et al.) based on statistical tools (such as correlation analysis and principal component analysis) and interactive visual analysis. Shape parameters of concentration time curves are investigated (as well as other quantities that we derived from them) to analyze brain regions that are affected by tumors. Low and high grade tumors are compared. In this talk, a short update on the current state of this research is presented, more results are expected during the weeks and months to come.", images = "images/hauser10brainPerf.png", thumbnails = "images/hauser10brainPerf_thumb.jpg", location = "Bergen, Norway", pres = "pdfs/hauser10brainPerfusion-pres.pdf" } @MISC {hauser10visualDialog, author = "Helwig Hauser", title = "Interactive Visualization as a Visual Dialog for Data Investigation", howpublished = "Talk at Visualiseringsdag Stockholm", month = "April 13", year = "2010", images = "images/hauser10visualDialog.png", thumbnails = "images/hauser10visualDialog_thumb.jpg", location = "Stockholm, Sweden", pres = "pdfs/hauser10visualDialog.pdf" } @MISC {kehrer10edaVis, author = "Johannes Kehrer", title = "Selected Opportunities for Integrating Statistics and Visualization in Multi-dimensional Data Exploration", howpublished = "Talk at EDAVis: Workshop on Exploratory Data Analysis and Visualisation", month = "May 27", year = "2010", abstract = "Visualization and statistics both facilitate the understanding of complex data characteristics, and there is a long history of relations between the two fields. Traditional approaches for data analysis often consider passive visualizations of statistical data properties. Interactive visual analysis, however, as addressed in this talk, allows the iterative exploration and analysis of data in a guided human computer dialog. Graphical representations of the data and well-proven interaction mechanisms are used to concurrently show, explore, and analyze complex (i.e., time-dependent, multi-variate, and/or multi-dimensional) data. Interesting subsets of the data are interactively selected (brushed) directly on the screen, the relations are investigated in other linked views (including 2D scatterplots, histograms, function graph views, parallel coordinates, but also 3D views of volumetric data).In recent work, we have studied the integration of large amounts of locally aggregated statistical data properties as well as measures of outlyingnessin an interactive visual analysis process. The approach is demonstrated on the visual analysis of multi-dimensional climate data. A discussion of possibilities explains how a further combination of interactive statisticalplots and proven interaction schemes from visualization research shows greatpotential for future research.", images = "images/kehrer10edavis.jpg", thumbnails = "images/kehrer10edavis_thumb.jpg", location = "Vienna, Austria" } @MASTERTHESIS {Eikeland10thesis, author = "Stian Eikeland", title = "Multi-Volume Visualization and Exploration", school = "Visualization Group, Department of Informatics, University of Bergen", year = "2010", type = "MSc. thesis", month = "sep", images = "images/P042_I01.jpg,images/P044_I01.jpg,images/P049_I01.jpg,images/P049_I02.jpg,images/P051_I02.jpg,images/P055_I03.jpg,images/P058_I01.jpg,images/P061_I01.jpg,", thumbnails = "images/P042_I01.jpg,images/P044_I01.jpg,images/P049_I01.jpg,images/P049_I02.jpg,images/P051_I02.jpg,images/P055_I03.jpg,images/P058_I01.jpg,images/P061_I01.jpg," } @MASTERTHESIS {Hammersland09thesis, author = "Yngve Devik Hammersland", title = "Visualization and Interaction with Medical Data in Immersive Environments", school = "Visualization Group, Department of Informatics, University of Bergen, Norway", year = "2009", type = "M.Sc. Thesis", month = "feb", images = "images/Immersion1.jpg,images/Immersion2.jpg,images/Ultrasound1.png,images/Ultrasound2.png,images/Ultrasound3.png,", thumbnails = "images/Immersion1.jpg,images/Immersion2.jpg,images/Ultrasound1.png,images/Ultrasound2.png,images/Ultrasound3.png," } @INCOLLECTION {ladstaedter09opac, author = "Florian Ladst{\"a}dter and Andrea K. Steiner and Bettina C. Lackner and Gottfried Kirchengast and Philipp Muigg and Johannes Kehrer and Helmut Doleisch", title = "SimVis: An Interactive Visual Field Exploration Tool Applied to Climate Research", booktitle = "New Horizons in Occultation Research", publisher = "Springer", year = "2009", editor = "A. Steiner and B. Pirscher and U. Foelsche and G. Kirchengast", pages = "235--245", abstract = "Climate research often deals with large multi-dimensional fields describing the state of the atmosphere. A novel approach to gain information about these large data sets has become feasible only recently using 4D visualization techniques. The Simulation Visualization (SimVis) software tool, developed by the VRVis Research Center (Vienna, Austria), uses such techniques to provide access to the data interactively and to explore and analyze large three-dimensional time-dependent fields. Non-trivial visualization approaches are applied to provide a responsive and useful interactive experience for the user. In this study we used SimVis for the investigation of climate research data sets. An ECHAM5 climate model run and the ERA-40 reanalysis data sets were explored, with the ultimate goal to identify parameters and regions reacting most sensitive to climate change, representing robust indicators. The focus lies on the upper troposphere-lower stratosphere (UTLS) region, in view of future applications of the findings to radio occultation (RO) climatologies. First results showing the capability of SimVis to deal with climate data, including trend time series and spatial distributions of RO parameters are presented.", images = "images/ladstaedter09opac.jpg", thumbnails = "images/ladstaedter09opac_thumb.jpg", isbn = "978-3-642-00321-9", url = "http://dx.doi.org/10.1007/978-3-642-00321-9_19" } @ARTICLE {fuchs09star, author = "Raphael Fuchs and Helwig Hauser", title = "Visualization of Multi-Variate Scientific Data", journal = "Computer Graphics Forum", year = "2009", volume = "28", number = "6", pages = "1670--1690", abstract = "In this state-of-the-art report we discuss relevant research worksrelated to the visualization of complex, multi-variate data. We discuss how different techniques take effect at specific stages of the visualization pipeline and how they apply to multi-variate data sets being composed of scalars, vectors and tensors. We also provide a categorization of these techniques with the aim for a better overview of related approaches. Based on this classification we highlight combinable and hybrid approaches and focus on techniques that potentially lead towards new directions in visualization research. In the second part of this paper we take a look at recent techniques that are useful for the visualization of complex data sets either because they are general purpose or because they can be adapted to specific problems.", images = "images/buerger07star1.png, images/buerger07star2.png", thumbnails = "images/buerger07star1_thumb.png, images/buerger07star2_thumb.png", url = "http://dx.doi.org/10.1111/j.1467-8659.2009.01429.x" } @ARTICLE {patel09knowledge, author = "Daniel Patel and {\O }yvind Sture and Helwig Hauser and Christopher Giertsen and Meister Eduard Gr{\"o}ller", title = "Knowledge-assisted visualization of seismic data", journal = "Computers \& Graphics", year = "2009", volume = "33", number = "5", pages = "585--596", abstract = "We present novel techniques for knowledge-assisted annotation and computer-assisted interpretation of seismic data for oil and gas exploration. We describe the existing procedure for oil and gas search which consists of manually extracting information from seismic data and then aggregating it into knowledge in a detail-oriented bottom-up approach. We then point out the weaknesses of this approach and propose how to improve on it by introducing a holistic computer-assisted top-down approach intended as a preparation step enabling a quicker, more focused and accurate bottom-up interpretation. The top-down approach also enables early representations of hypotheses and knowledge using domain-specific textures for annotating the data. Finally we discuss how these annotations can be extended to 3D for volumetric annotations.", images = "images/patel09knowledge2.jpg, images/patel09knowledge1.jpg, images/patel09knowledge3.jpg, images/patel09knowledge4.jpg", thumbnails = "images/patel09knowledge2_thumb.jpg, images/patel09knowledge1_thumb.jpg, images/patel09knowledge3_thumb.jpg, images/patel09knowledge4_thumb.jpg", url = "http://dx.doi.org/10.1016/j.cag.2009.06.005" } @ARTICLE {matkovic09surfaces, author = "Kresimir Matkovic and Denis Gracanin and Borislav Klarin and Helwig Hauser", title = "Interactive Visual Analysis of Complex Scientific Data as Families of Data Surfaces", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2009", volume = "15", number = "6", pages = "1351--1358", abstract = "The widespread use of computational simulation in science and engineering provides challenging research opportunities. Multiple independent variables are considered and large and complex data are computed, especially in the case of multi-run simulation. Classical visualization techniques deal well with 2D or 3D data and also with time-dependent data. Additional independent dimensions, however, provide interesting new challenges. We present an advanced visual analysis approach that enables a thorough investigation of families of data surfaces, i.e., datasets, with respect to pairs of independent dimensions. While it is almost trivial to visualize one such data surface, the visual exploration and analysis of many such data surfaces is a grand challenge, stressing the users perception and cognition. We propose an approach that integrates projections and aggregations of the data surfaces at different levels (one scalar aggregate per surface, a 1D profile per surface, or the surface as such). We demonstrate the necessity for a flexible visual analysis system that integrates many different (linked) views for making sense of this highly complex data. To demonstrate its usefulness, we exemplify our approach in the context of a meteorological multi-run simulation data case and in the context of the engineering domain, where our collaborators are working with the simulation of elastohydrodynamic (EHD) lubrication bearing in the automotive industry.", images = "images/matkovic09surfaces.jpg, images/matkovic09surfaces2.jpg", thumbnails = "images/matkovic09surfaces_thumb.jpg, images/matkovic09surfaces2_thumb.jpg", event = "IEEE Visualization 2009", url = "http://dx.doi.org/10.1109/TVCG.2009.155" } @ARTICLE {lampe09cuvicentric, author = "Ove Daae Lampe and Carlos Correa and Kwan-Liu Ma and Helwig Hauser", title = "Curve-Centric Volume Reformation for Comparative Visualization", journal = "IEEE Transactions on Visualization and Computer Graphics", year = "2009", volume = "15", number = "6", pages = "1235--1242", abstract = "We present two visualization techniques for curve-centric volume reformation with the aim to create compelling comparative visualizations. A curve-centric volume reformation deforms a volume, with regards to a curve in space, to create a new space in which the curve evaluates to zero in two dimensions and spans its arc-length in the third. The volume surrounding the curve is deformed such that spatial neighborhood to the curve is preserved. The result of the curve-centric reformation produces images where one axis is aligned to arc-length, and thus allows researchers and practitioners to apply their arc-length parameterized data visualizations in parallel for comparison. Furthermore we show that when visualizing dense data, our technique provides an inside out projection, from the curve and out into the volume, which allows for inspection what is around the curve. Finally we demonstrate the usefulness of our techniques in the context of two application cases. We show that existing data visualizations of arc-length parameterized data can be enhanced by using our techniques, in addition to creating a new view and perspective on volumetric data around curves. Additionally we show how volumetric data can be brought into plotting environments that allow precise readouts. In the first case we inspect streamlines in a flow field around a car, and in the second we inspect seismic volumes and well logs from drilling.", images = "images/lampe09cuvicentric4.jpg, images/lampe09cuvicentric5.jpg, images/lampe09cuvicentric2.jpg, images/lampe09cuvicentric3.jpg", thumbnails = "images/lampe09cuvicentric4_thumb.jpg, images/lampe09cuvicentric5_thumb.jpg, images/lampe09cuvicentric2_thumb.jpg, images/lampe09cuvicentric3_thumb.jpg", event = "IEEE Visualization 2009", url = "http://dx.doi.org/10.1109/TVCG.2009.136" } @INCOLLECTION {hauserSchumann09pipeline, author = "Helwig Hauser and Heidrun Schumann", title = "Visualization Pipeline", booktitle = "Encyclopedia of Database Systems", publisher = "Springer US", year = "2009", editor = "Ling Liu and M. Tamer {\"O}zsu", pages = "3414--3416", abstract = "Without Abstract", images = "images/hauserSchumann09pipeline.jpg, images/hauserSchumann09pipeline2.jpg", thumbnails = "images/hauserSchumann09pipeline_thumb.jpg, images/hauserSchumann09pipeline2_thumb.jpg", url = "http://dx.doi.org/10.1007/978-0-387-39940-9_1133" } @PHDTHESIS {balabanian09thesis, author = "Jean-Paul Balabanian", title = "Multi-Aspect Visualization: Going from Linked Views to Integrated Views", school = "Department of Informatics, University of Bergen, Norway", year = "2009", month = "oct", abstract = "This thesis is a delve into the matter of visualization integration. There are many approaches to visualizing volume data and often several of these approaches can appropriately be used at the same time to visualize dirent aspects. The usual way is to visualize these aspects separately in dirent views, but integrating the visualizations into the same view can often be the superior approach. We describe the two most used approaches to visualizing several aspects at the same time; linked views and integrated views. We describe some approaches to create integrated visualizations by showing where in the visualization pipeline the integration takes place. We present work produced by the author describing the integrated visualizations developed.", pdf = "pdfs/balabanian09mav.pdf", images = "images/balabanian09thesis.jpg, images/balabanian09thesis1.jpg, images/balabanian10hierarchical2.jpg, images/balabanian10hierarchical3.jpg,", thumbnails = "images/balabanian09thesis_thumb.jpg, images/balabanian09thesis1_thumb.jpg, images/balabanian10hierarchical2_thumb.jpg, images/balabanian10hierarchical3_thumb.jpg,", project = "illvis" } @PHDTHESIS {patel09thesis, author = "Daniel Patel", title = "Expressive Visualization and Rapid Interpretation of Seismic Volumes", school = "Department of Informatics, University of Bergen, Norway", year = "2009", month = "oct", abstract = "One of the most important resources in the world today is energy. Oil and gas provide two thirds of the world energy consumption, making the world completely dependent on it. Locating and recovering the remaining oil and gas reserves will be of high focus in society until competitive energy sources are found. The search for hydrocarbons is broadly speaking the topic of this thesis. Seismic measurements of the subsurface are collected to discover oil and gas trapped in the ground. Identifying oil and gas in the seismic measurements requires visualization and interpretation. Visualization is needed to present the data for further analysis. Interpretation is performed to identify important structures. Visualization is again required for presenting these structures to the user. This thesis investigates how computer assistance in producing high-quality visualizations and in interpretation can result in expressive visualization and rapid interpretation of seismic volumes. Expressive visualizations represent the seismic data in an easily digestible, intuitive and pedagogic form. This enables rapid interpretation which accelerates the finding of important structures.", images = "images/patel09thesis.jpg, images/patel09thesis1.jpg, images/patel09thesis3.jpg, images/patel09thesis2.jpg", thumbnails = "images/patel09thesis_thumb.jpg, images/patel09thesis1_thumb.jpg, images/patel09thesis3_thumb.jpg, images/patel09thesis2_thumb.jpg", url = "http://www.cg.tuwien.ac.at/research/publications/2009/patel-2009-evr/", project = "illvis" } @MISC {kehrer09potsdam, author = "Johannes Kehrer", title = "Interactive Visual Analysis of Multi-run Climate Data", howpublished = "Invited talk at Potsdam Institute for Climate Impact Research (PIK)", month = "December", year = "2009", abstract = "The increasing complexity of data stemming from climate models and observations creates new challenges for data analysis. Traditional approaches are often based on computing statistical data properties. Interactive visual analysis, on the other hand, allows the stepwise exploration of the data in a guided human-computer dialog. It uses graphical representations of the data to interactively explore the data in multiple linked views. This allows the analyst to rapidly generate and analyze hypotheses, to identify data deficiencies, and to explore data trends and outliers.In an ongoing cooperation between the University of Bergen, Norway, the Potsdam Institute for Climate Impact Research (PIK), and the SimVis GmbH, Vienna, we used and extended our visual analysis framework to also work with multi-run climate data. In the framework, we relate the original multi-run data and derived statistical properties to each other. This allows the analyst to work in parallel with both, the aggregated data representation and the original multi-run data. We demonstrate this in a visual sensitivity analysis of the multi-run data.", images = "images/kehrer11heterogeneous2.jpg", thumbnails = "images/kehrer09potsdam_thumb.jpg", location = "Potsdam, Germany" } @MISC {kehrer09wegener, author = "Helmut Doleisch and Johannes Kehrer", title = "SimVis \– eine neue Technologie zur interaktiven visuellen Analyse: Konzepte und Anwendungen im Umfeld der Klimaforschung", howpublished = "Invited talk at Wegener Center for Climate and Global Change", month = "December", year = "2009", images = "images/ladstaedter10exploration.jpg", thumbnails = "images/ladstaedter10exploration_thumb.jpg", location = "Graz, Austria" } @ARTICLE {nylund2009sonography, author = "Kim Nylund and Svein {\O }degaard and Trygve Hausken and Geir Folvik and Golen Arslan Lied and Ivan Viola and Helwig Hauser and Odd Helge Gilja", title = "Sonography of the small intestine", journal = "World Journal of Gastroenterology", year = "2009", volume = "15", number = "11", pages = "1319--1330", month = "March", abstract = "In the last two decades, there has been substantial development in the diagnostic possibilities for examining the small intestine. Compared with computerized tomography, magnetic resonance imaging, capsule endoscopy and double-balloon endoscopy, ultrasonography has the advantage of being cheap, portable, flexible and user- and patient-friendly, while at the same time providing the clinician with image data of high temporal and spatial resolution. The method has limitations with penetration in obesity and with intestinal air impairing image quality. The flexibility ultrasonography offers the examiner also implies that a systematic approach during scanning is needed. This paper reviews the basic scanning techniques and new modalities such as contrast-enhanced ultrasound, elastography, strain rate imaging, hydrosonography, allergosonography, endoscopic sonography and nutritional imaging, and the literature on disease-specific findings in the small intestine. Some of these methods have shown clinical benefit, while others are under research and development to establish their role in the diagnostic repertoire. However, along with improved overall image quality of new ultrasound scanners, these methods have enabled more anatomical and physiological changes in the small intestine to be observed. Accordingly, ultrasound of the small intestine is an attractive clinical tool to study patients with a range of diseases.", images = "images/nylund09sonosmall.jpg", thumbnails = "images/nylund09sonosmall_thumb.jpg", url = "http://www.wjgnet.com/1007-9327/15/1319.pdf", project = "medviz" } @MASTERTHESIS {Lie09thesis, author = "Andreas Lie", title = "Advanced Storytelling for Volume Visualization", school = "Visualization Group, Department of Informatics, University of Bergen", year = "2009", type = "M.Sc. Thesis", month = "Nov", images = "images/Capture2.PNG,images/Capture3.PNG,images/Capture4.PNG,images/Capture5.PNG,images/Capture6.PNG,images/Capture7.PNG,images/Capture8.PNG,images/Capture9.PNG,images/front.PNG,", thumbnails = "images/Capture2.PNG,images/Capture3.PNG,images/Capture4.PNG,images/Capture5.PNG,images/Capture6.PNG,images/Capture7.PNG,images/Capture8.PNG,images/Capture9.PNG,images/front.PNG," } @BOOK {sbert09informationTheory, author = "Mateu Sbert and Miquel Feixas and Jaume Rigau and Miguel Chover and Ivan Viola", title = "Information Theory Tools for Computer Graphics", publisher = "Morgan and Claypool Publishers Colorado", year = "2009", series = "Synthesis Lectures on Computer Graphics and Animation", abstract = "Information theory (IT) tools, widely used in scientific fields such as engineering, physics, genetics, neuroscience, and many others,are also emerging as useful transversal tools in computer graphics. In this book, we present the basic concepts of IT and how they have been applied to the graphics areas of radiosity, adaptive ray-tracing, shape descriptors, viewpoint selection and saliency, scientific visualization, and geometry simplification. Some of the approaches presented, such as the viewpoint techniques, are now the state of the art in visualization. Almost all of the techniques presented in this book have been previously published in peer-reviewed conference proceedings or international journals. Here, we have stressed their common aspects and presented them in an unified way, so the reader can clearly see which problems IT tools can help solve, which specific tools to use, and how to apply them. A basic level of knowledge in computer graphics is required but basic concepts in IT are presented. The intended audiences are both students and practitioners of the fields above and related areas in computer graphics. In addition, IT practitioners will learn about these applications.", images = "images/viola09hand.jpg", thumbnails = "images/viola09hand_thumb.jpg", isbn = "1598299298", url = "http://dx.doi.org/10.2200/S00208ED1V01Y200909CGR012", project = "illustrasound,illvis" } @MASTERTHESIS {Birkeland08thesis, author = "{\AA}smund Birkeland", title = "View-Dependent Peel-Away Visualization for Volumetric Data", school = "Visualization Group, Department of Informatics, University of Bergen", year = "2008", type = "M.Sc. Thesis", month = "Nov", images = "images/illustration1Birkeland.png,images/illustration2Birkeland.png,images/illustration3Birkeland.png,images/illustration4Birkeland.png,", thumbnails = "images/illustration1Birkeland.png,images/illustration2Birkeland.png,images/illustration3Birkeland.png,images/illustration4Birkeland.png," } @ARTICLE {patel08seismicAnalyzer, author = "Daniel Patel and Christopher Giertsen and John Thurmond and John Gjelberg and Meister Eduard Gr{\"o}ller", title = "The Seismic Analyzer: Interpreting and Illustrating 2D Seismic Data", journal = "IEEE Transactions on Visualization and Computer Graphics (IEEE TVCG)", year = "2008", volume = "14", number = "6", pages = "1571--1578", month = "Oct", abstract = "We present a toolbox for quickly interpreting and illustrating 2D slices of seismic volumetric reflection data. Searching for oil and gas involves creating a structural overview of seismic reflection data to identify hydrocarbon reservoirs. We improve the search of seismic structures by precalculating the horizon structures of the seismic data prior to interpretation. We improve the annotation of seismic structures by applying novel illustrative rendering algorithms tailored to seismic data, such as deformed texturing and line and texture transfer functions. The illustrative rendering results in multi-attribute and scale invariant visualizations where features are represented clearly in both highly zoomed in and zoomed out views. Thumbnail views in combination with interactive appearance control allows for a quick overview of the data before detailed interpretation takes place. These techniques help reduce the work of seismic illustrators and interpreters.", vid = "vids/patel08vis.html", images = "images/patel08seismic.png, images/patel08seismic4.jpg, images/patel08seismic3.jpg, images/patel08seismic1.png", thumbnails = "images/patel08seismic_thumb.png, images/patel08seismic4_thumb.jpg, images/patel08seismic3_thumb.jpg, images/patel08seismic1_thumb.png", event = "IEEE Visualization 2008", location = "Columbus, Ohio, USA", url = "http://dx.doi.org/10.1109/TVCG.2008.170", pres = "pdfs/patel08vis-presentation.pdf" } @ARTICLE {rautek08illustrative, author = "Peter Rautek and Stefan Bruckner and Meister Eduard Gr{\"o}ller and Ivan Viola", title = "Illustrative Visualization: New Technology or Useless Tautology?", journal = "SIGGRAPH Comput. Graph.", year = "2008", volume = "42", number = "3", images = "images/rautek08illustrative.jpg", thumbnails = "images/rautek08illustrative_thumb.jpg", doi = "http://doi.acm.org/10.1145/1408626.1408633", url = "http://doi.acm.org/10.1145/1408626.1408633", publisher = "ACM", address = "New York, NY, USA", project = "illvis" } @ARTICLE {fuchs08parallel, author = "Raphael Fuchs and Ronald Peikert and Helwig Hauser and Filip Sadlo and Philipp Muigg", title = "Parallel Vectors Criteria for Unsteady Flow Vortices", journal = "IEEE Transactions on Visualization and Computer Graphics (IEEE TVCG)", year = "2008", volume = "14", number = "3", pages = "615--626", month = "May", abstract = "Feature-based flow visualization is naturally dependent on feature extraction. To extract flow features, often higher-order properties of the flow data are used such as the Jacobian or curvature properties, implicitly describing the flow features in terms of their inherent flow characteristics (e.g., collinear flow and vorticity vectors). In this paper we present recent research which leads to the (not really surprising) conclusion that feature extraction algorithms need to be extended to a time-dependent analysis framework (in terms of time derivatives) when dealing with unsteady flow data. Accordingly, we present two extensions of the parallel vectors based vortex extraction criteria to the time-dependent domain and show the improvements of feature-based flow visualization in comparison to the steady versions of this extraction algorithm both in the context of a high-resolution dataset, i.e., a simulation specifically designed to evaluate our new approach, as well as for a real-world dataset from a concrete application.", pdf = "http://dx.doi.org10.1109/TVCG.2007.70633", images = "images/fuchs08parallel.jpg, images/fuchs08parallel1.jpg", thumbnails = "images/fuchs08parallel_thumb.jpg, images/fuchs08parallel1_thumb.jpg", keywords = "Time-Varying Data Visualization, Vortex Feature Detection", url = "http://www.cg.tuwien.ac.at/research/publications/2008/fuchs_raphael_2007_par/" } @ARTICLE {Muigg08four, author = "Philipp Muigg and Johannes Kehrer and Steffen Oeltze and Harald Piringer and Helmut Doleisch and Bernhard Preim and Helwig Hauser", title = "A Four-level Focus+Context Approach to Interactive Visual Analysis of Temporal Features in Large Scientific Data", journal = "Computer Graphics Forum", year = "2008", volume = "27", number = "3", pages = "775--782", month = "may", abstract = "In this paper we present a new approach to the interactive visual analysis of time-dependent scientific data both from measurements as well as from computational simulation by visualizing a scalar function over time for each of tenthousands or even millions of sample points. In order to cope with overdrawing and cluttering, we introduce a new four-level method of focus+context visualization. Based on a setting of coordinated, multiple views (with linking and brushing), we integrate three different kinds of focus and also the context in every single view. Per data item we use three values (from the unit interval each) to represent to which degree the data item is part of the respective focus level. We present a color compositing scheme which is capable of expressing all three values in a meaningful way, taking semantics and their relations amongst each other (in the context of our multiple linked view setup) into account. Furthermore, we present additional image-based postprocessing methods to enhance the visualization of large sets of function graphs, including a texture-based technique based on line integral convolution (LIC). We also propose advanced brushing techniques which are specific to the timedependent nature of the data (in order to brush patterns over time more efficiently). We demonstrate the usefulness of the new approach in the context of medical perfusion data.", images = "images/muigg08_eurovis3.jpg, images/muigg08_eurovis1.jpg, images/muigg08_eurovis2.jpg", thumbnails = "images/muigg08_eurovis3_thumb.jpg, images/muigg08_eurovis1_thumb.jpg, images/muigg08_eurovis2_thumb.jpg", event = "EuroVis 2008", location = "Eindhooven, Netherlands", url = "http://dx.doi.org/10.1111/j.1467-8659.2008.01207.x" } @ARTICLE {freiler08setTyped, author = "Wolfgang Freiler and Kresimir Matkovic and Helwig Hauser", title = "Interactive Visual Analysis of Set-Typed Data", journal = "IEEE Transactions on Visualization and Computer Graphics (IEEE TVCG)", year = "2008", volume = "14", number = "6", pages = "1340--1347", month = "Oct", abstract = "While it is quite typical to deal with attributes of different data types in the visualization of heterogeneous and multivariate datasets, most existing techniques still focus on the most usual data types such as numerical attributes or strings. In this paper we present a new approach to the interactive visual exploration and analysis of data that contains attributes which are of set type. A set-typed attribute of a data item -- like one cell in a table -- has a list of n>=0 elements as its value. We present the setogram as a new visualization approach to represent data of set type and to enable interactive visual exploration and analysis. We also demonstrate how this approach is capable to help in dealing with datasets that have a larger number of dimensions (more than a dozen or more), especially also in the context of categorical data. To illustrate the effectiveness of our approach, we present the interactive visual analysis of a CRM dataset with data from a questionnaire on the education and shopping habits of about 90000 people.", images = "images/freiler08setTyped.png, images/freiler08setTyped1.png, images/freiler08setTyped2.png", thumbnails = "images/freiler08setTyped_thumb.png, images/freiler08setTyped1_thumb.png, images/freiler08setTyped2_thumb.png", event = "IEEE Information Visualization 2008", location = "Columbus, Ohio, USA", url = "http://dx.doi.org/10.1109/TVCG.2008.144" } @MASTERTHESIS {Nes08thesis, author = "Gisle Nes", title = "Physically Plausible Weather Visualization", school = "Visualization Group, Department of Informatics, University of Bergen", year = "2008", type = "M.Sc. Thesis", month = "jun", images = "images/illustration1.png,images/illustration2.png,images/illustration3.png,images/illustration4.png,", thumbnails = "images/illustration1.png,images/illustration2.png,images/illustration3.png,images/illustration4.png," } @ARTICLE {kehrer08hypothesisGeneration, author = "Johannes Kehrer and Florian Ladst{\"a}dter and Philipp Muigg and Helmut Doleisch and Andrea Steiner and Helwig Hauser", title = "Hypothesis Generation in Climate Research with Interactive Visual Data Exploration", journal = "IEEE Transactions on Visualization and Computer Graphics (IEEE TVCG)", year = "2008", volume = "14", number = "6", pages = "1579--1586", month = "Oct", abstract = "One of the most prominent topics in climate research is the investigation, detection, and allocation of climate change. In this paper, we aim at identifying regions in the atmosphere (e.g., certain height layers) which can act as sensitive and robust indicators for climate change. We demonstrate how interactive visual data exploration of large amounts of multi-variate and time-dependent climate data enables the steered generation of promising hypotheses for subsequent statistical evaluation. The use of new visualization and interaction technology -- in the context of a coordinated multiple views framework -- allows not only to identify these promising hypotheses, but also to efficiently narrow down parameters that are required in the process of computational data analysis. Two datasets, namely an ECHAM5 climate model run and the ERA-40 reanalysis incorporating observational data, are investigated. Higher-order information such as linear trends or signal-to-noise ratio is derived and interactively explored in order to detect and explore those regions which react most sensitively to climate change. As one conclusion from this study, we identify an excellent potential for usefully generalizing our approach to other, similar application cases, as well.", vid = "vids/kehrer08hypothesis.html", images = "images/kehrer08vis01.jpg, images/kehrer08vis03.jpg, images/kehrer08vis04.png", thumbnails = "images/kehrer08vis01_thumb.jpg, images/kehrer08vis03_thumb.jpg, images/kehrer08vis04_thumb.png", event = "IEEE Visualization 2008", location = "Columbus, Ohio, USA", url = "http://dx.doi.org/10.1109/TVCG.2008.139", pres = "pdfs/kehrer08vis-presentation.pdf" } @ARTICLE {matkovic08visualSteering, author = "Kresimir Matkovic and Denis Gracanin and Mario Jelovic and Helwig Hauser", title = "Interactive Visual Steering - Rapid Visual Prototyping of a Common Rail Injection System", journal = "IEEE Transactions on Visualization and Computer Graphics (IEEE TVCG)", year = "2008", volume = "14", number = "6", pages = "1699--1706", month = "Oct", abstract = "Interactive steering with visualization has been a common goal of the visualization research community for twenty years, but it is rarely ever realized in practice. In this paper we describe a successful realization of a tightly coupled steering loop, integrating new simulation technology and interactive visual analysis in a prototyping environment for automotive industry system design. Due to increasing pressure on car manufacturers to meet new emission regulations, to improve efficiency, and to reduce noise, both simulation and visualization are pushed to their limits. Automotive system components, such as the powertrain system or the injection system, have an increasing number of parameters, and new design approaches are required. It is no longer possible to optimize such a system solely based on experience or forward optimization. By coupling interactive visualization with the simulation back-end (computational steering), it is now possible to quickly prototype a new system, starting from a non-optimized initial prototype and the corresponding simulation model. The prototyping continues through the refinement of the simulation model, of the simulation parameters and through trial-and-error attempts to an optimized solution. The ability to early see the first results from a multidimensional simulation space -- thousands of simulations are run for a multidimensional variety of input parameters -- and to quickly go back into the simulation and request more runs in particular parameter regions of interest significantly improves the prototyping process and provides a deeper understanding of the system behavior. The excellent results which we achieved for the common rail injection system strongly suggest that our approach has a great potential of being generalized to other, similar scenarios.", images = "images/matkovic08vis.png, images/matkovic08vis1.png, images/matkovic08vis3.png, images/matkovic08vis4.png", thumbnails = "images/matkovic08vis_thumb.png, images/matkovic08vis1_thumb.png, images/matkovic08vis3_thumb.png, images/matkovic08vis4_thumb.png", event = "IEEE Visualization 2008", location = "Columbus, Ohio, USA", url = "http://dx.doi.org/10.1109/TVCG.2008.145" } @ARTICLE {Gilja2007, author = "Odd Helge Gilja and Trygve Hausken and Jan G. Hatlebakk and Svein {\O }degaard and Arnold Berstad and Ivan Viola and Christopher Giertsen and Hans Gregersen", title = "Advanced Imaging and Visualization in Gastrointestinal Disorders", journal = "World Journal of Gastroenterology", year = "2007", volume = "13", number = "9", pages = "1408--1421", abstract = "Advanced medical imaging and visualization has a strong impact on research and clinical decision making in gastroenterology. The aim of this paper is to show how imaging and visualization can disclose structural and functional abnormalities of the gastrointestinal (GI) tract. Imaging methods such as ultrasonography, magnetic resonance imaging (MRI), endoscopy, endosonography, and elastography will be outlined and visualization with Virtual Reality and haptic methods. Ultrasonography is a versatile method that can be used to evaluate antral contractility, gastric emptying, transpyloric flow, gastric configuration, intragastric distribution of meals, gastric accommodation and strain measurement of the gastric wall. Advanced methods for endoscopic ultrasound, three-dimensional (3D) ultrasound, and tissue Doppler ( Strain Rate Imaging) provide detailed information of the GI tract. Food hypersensitivity reactions including gastrointestinal reactions due to food allergy can be visualized by ultrasonography and MRI. Development of multi- parametric and multi-modal imaging may increase diagnostic benefits and facilitate fusion of diagnostic and therapeutic imaging in the future.", pdf = "http://www.wjgnet.com/1007-9327/13/1408.pdf", images = "images/gilja_2007_wjg.jpg", thumbnails = "images/gilja_2007_wjg_thumbnail.jpg", url = "http://www.wjgnet.com/1007-9327/13/1408.asp" } @ARTICLE {muigg07hybrid, author = "Philipp Muigg and Markus Hadwiger and Helmut Doleisch and Helwig Hauser", title = "Scalable Hybrid Unstructured and Structured Grid Raycasting", journal = "IEEE Transactions on Visualization and Computer Graphics (IEEE TVCG)", year = "2007", volume = "13", number = "6", pages = "1592--1599", month = "nov", abstract = "This paper presents a scalable framework for real-time raycasting of large unstructured volumes that employs a hybrid bricking approach. It adaptively combines original unstructured bricks in important (focus) regions, with structured bricks that are resampled on demand in less important (context) regions. The basis of this focus+context approach is interactive specification of a scalar degree-of-interest (DOI) function. Thus, rendering always considers two volumes simultaneously: a scalar data volume, and the current DOI volume. The crucial problem of visibility sorting is solved by raycasting individual bricks and compositing in visibility order from front to back. In order to minimize visual errors at the grid boundary, it is always rendered accurately, even for resampled bricks. A variety of different rendering modes can be combined, including contour enhancement. A very important property of our approach is that it supports a variety of cell types natively, i.e., it is not constrained to tetrahedral grids, even when interpolation within cells is used. Moreover, our framework can handle multi-variate data, e.g., multiple scalar channels such as temperature or pressure, as well as time-dependent data. The combination of unstructured and structured bricks with different quality characteristics such as the type of interpolation or resampling resolution in conjunction with custom texture memory management yields a very scalable system.", images = "images/muigg07hybrid.png, images/muigg07hybrid1.png, images/muigg07hybrid2.png", thumbnails = "images/muigg07hybrid_thumb.png, images/muigg07hybrid1_thumb.png, images/muigg07hybrid2_thumb.png", issn = "1077-2626", location = "Sacramento, California, USA", event = "IEEE Visualization 2007", url = "http://dx.doi.org/10.1109/TVCG.2007.70588", publisher = "IEEE Computer Society" } @ARTICLE {Lampe2007TMV, author = "Ove Daae Lampe and Ivan Viola and Nathalie Reuter and Helwig Hauser", title = "Two-Level Approach to Efficient Visualization of Protein Dynamics", journal = "IEEE Transactions on Visualization and Computer Graphics (IEEE TVCG)", year = "2007", volume = "13", number = "6", pages = "1616--1623", month = "nov", abstract = "Proteins are highly flexible and large amplitude deformations of their structure, also called slow dynamics, are often decisive to their function. We present a two-level rendering approach that enables visualization of slow dynamics of large protein assemblies. Our approach is aligned with a hierarchical model of large scale molecules. Instead of constantly updating positions of large amounts of atoms, we update the position and rotation of residues, i.e., higher level building blocks of a protein. Residues are represented by one vertex only indicating its position and additional information defining the rotation. The atoms in the residues are generated on-the-fly on the GPU, exploiting the new graphics hardware geometry shader capabilities. Moreover, we represent the atoms by billboards instead of tessellated spheres. Our representation is then significantly faster and pixel precise. We demonstrate the usefulness of our new approach in the context of our collaborative bioinformatics project.", pdf = "pdfs/lampe_2007_tvcg.pdf", images = "images/moleculevr_single_mol-20070329-0857270.jpeg, images/color_per_chain.jpeg, images/nanoThickWallSleveCHonly_anaglyph.jpeg, images/phi29Contour.jpeg, images/python 2007-06-25 23-07-54-84.jpeg, images/python 2007-06-25 23-31-18-14.jpeg", thumbnails = "images/moleculevr_single_mol-20070329-0857270_thumb.jpeg, images/color_per_chain_thumb.jpeg, images/nanoThickWallSleveCHonly_anaglyph_thumb.jpeg, images/phi29Contour_thumb.jpeg, images/python 2007-06-25 23-07-54-84_thumb.jpeg, images/python 2007-06-25 23-31-18-14_thumb.jpeg", event = "IEEE Visualization 2007", location = "Sacramento, California, USA", issn = "1077-2626" } @ARTICLE {oeltze07perfusion, author = "Steffen Oeltze and Helmut Doleisch and Helwig Hauser and Philipp Muigg and Bernhard Preim", title = "Interactive Visual Analysis of Perfusion Data", journal = "IEEE Transactions on Visualization and Computer Graphics (IEEE TVCG)", year = "2007", volume = "13", number = "6", pages = "1392-1399", month = "nov", abstract = "Perfusion data are dynamic medical image data which characterize the regional blood flow in human tissue. These data bear a great potential in medical diagnosis, since diseases can be better distinguished and detected at an earlier stage compared to static image data. The wide-spread use of perfusion data is hampered by the lack of efficient evaluation methods. For each voxel, a time-intensity curve characterizes the enhancement of a contrast agent. Parameters derived from these curves characterize the perfusion and have to be integrated for diagnosis. The diagnostic evaluation of this multi-field data is challenging and time-consuming due to its complexity. For the visual analysis of such datasets, feature-based approaches allow to reduce the amount of data and direct the user to suspicious areas. We present an interactive visual analysis approach for the evaluation of perfusion data. For this purpose, we integrate statistical methods and interactive feature specification. Correlation analysis and Principal Component Analysis (PCA) are applied for dimensionreduction and to achieve a better understanding of the inter-parameter relations. Multiple, linked views facilitate the definition of features by brushing multiple dimensions. The specification result is linked to all views establishing a focus+context style of visualization in 3D. We discuss our approach with respect to clinical datasets from the three major application areas: ischemic stroke diagnosis, breast tumor diagnosis, as well as the diagnosis of the coronary heart disease (CHD). It turns out that the significance of perfusion parameters strongly depends on the individual patient, scanning parameters, and data pre-processing.", images = "images/oeltze07perfusion.png, images/oeltze07perfusion1.png", thumbnails = "images/oeltze07perfusion_thumb.png, images/oeltze07perfusion1_thumb.png", issn = "1077-2626", publisher = "IEEE Computer Society", location = "Sacramento, California, USA", event = "IEEE Visualization 2007", url = "http://dx.doi.org/10.1109/TVCG.2007.70569" }