| 1. |
- Behrendt, Benjamin, et al.
(författare)
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Evolutionary Pathlines for Blood Flow Exploration in Cerebral Aneurysms
- 2019
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Ingår i: Eurographics Workshop on Visual Computing for Biology and Medicine. - : The Eurographics Association. - 9783038680819
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Konferensbidrag (refereegranskat)abstract
- Blood flow simulations play an important role for the understanding of vascular diseases, such as aneurysms. However, analysis of the resulting flow patterns, especially comparisons across patient groups, are challenging. Typically, the hemodynamic analysis relies on trial and error inspection of the flow data based on pathline visualizations and surface renderings. Visualizing too many pathlines at once may obstruct interesting features, e.g., embedded vortices, whereas with too little pathlines, particularities such as flow characteristics in aneurysm blebs might be missed. While filtering and clustering techniques support this task, they require the pre-computation of pathlines densely sampled in the space-time domain. Not only does this become prohibitively expensive for large patient groups, but the results often suffer from undersampling artifacts. In this work, we propose the usage of evolutionary algorithms to reduce the overhead of computing pathlines that do not contribute to the analysis, while simultaneously reducing the undersampling artifacts. Integrated in an interactive framework, it efficiently supports the evaluation of hemodynamics for clinical research and treatment planning in case of cerebral aneurysms. The specification of general optimization criteria for entire patient groups allows the blood flow data to be batch-processed. We present clinical cases to demonstrate the benefits of our approach especially in presence of aneurysm blebs. Furthermore, we conducted an evaluation with four expert neuroradiologists. As a result, we report advantages of our method for treatment planning to underpin its clinical potential.
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| 2. |
- Cencetti, Michele, et al.
(författare)
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CROSS DRIVE: A Collaborative Virtual Reality Workplace for Space Science Data Exploitation and Rover Operations Engineering
- 2016
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Ingår i: SECESA 2016.
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Konferensbidrag (refereegranskat)abstract
- The CrossDrive Project develops Distributed and Collaborative Infrastructure based on advanced Immersive Virtual Reality tools for the analysis and management of Scientific Data and Operational Activities of planetary spacecraft. The Collaborative Workspace encompasses advanced technological solutions for central storage processing, 3D visualisation and Virtual Presence in Immersive Virtual Reality environments, to support Space Data Analysis and Space Operations. Science objectives are share and correlate Atmospheric data, analysis and simulations based on the actual main Mars’ satellites (MEX and MRO); compare and correlate data for Geology and Geodesy; benchmark satellite and ground based Mars atmospheric measurements.
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| 3. |
- Engelke, Wito, 1983-, et al.
(författare)
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Atmospheric Impact of Volcano Eruptions
- 2014
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Ingår i: Proceedings IEEE SciVis 2014. - : Publication Server of Zuse Institute Berlin (ZIB).
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Konferensbidrag (refereegranskat)abstract
- The analysis of data that captures volcanic eruptions and their atmospheric aftermath plays an important role for domain experts to gain a deeper understanding of the volcanic eruption and their consequences for atmosphere, climate and air traffic. Thereby, one major challenge is to extract and combine the essential information, which is spread over various, mostly sparse data sources. This requires a careful integration of each data set with its strength and limitations. The sparse, but more reliable measurement data is mainly used to calibrate the more dense simulation data. This work combines a collection of visualization approaches into an exploitative framework. The goal is to support the domain experts to build a complete picture of the situation. But it is also important to understand the individual data sources, the wealth of their information and the quality of the simulation results. All presented methods are designed for direct interaction with the data from different perspectives rather than the sole generation of some final images.
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| 4. |
- Engelke, Wito, 1983-, et al.
(författare)
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Autonomous Particles for Interactive Flow Visualization
- 2019
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Ingår i: Computer graphics forum (Print). - : John Wiley & Sons. - 0167-7055 .- 1467-8659. ; :1, s. 248-259
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Tidskriftsartikel (refereegranskat)abstract
- We present an interactive approach to analyse flow fields using a new type of particle system, which is composed of autonomous particles exploring the flow. While particles provide a very intuitive way to visualize flows, it is a challenge to capture the important features with such systems. Particles tend to cluster in regions of low velocity and regions of interest are often sparsely populated. To overcome these disadvantages, we propose an automatic adaption of the particle density with respect to local importance measures. These measures are user defined and the systems sensitivity to them can be adjusted interactively. Together with the particle history, these measures define a probability for particles to multiply or die, respectively. There is no communication between the particles and no neighbourhood information has to be maintained. Thus, the particles can be handled in parallel and support a real‐time investigation of flow fields. To enhance the visualization, the particles' properties and selected field measures are also used to specify the systems rendering parameters, such as colour and size. We demonstrate the effectiveness of our approach on different simulated vector fields from technical and medical applications.
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| 5. |
- Engelke, Wito, 1983-, et al.
(författare)
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Evolutionary Lines for Flow Visualization
- 2018
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Ingår i: EuroVis 2018, 20th EG/VGTC Conference on Visualization, 4-8 June, Brno, Czech Republic. - : The Eurographics Association. - 9783038680604 ; , s. 7-11
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Konferensbidrag (refereegranskat)abstract
- In this work we explore evolutionary algorithms for selected a visualization application. We demonstrate its potential using an example from flow visualization showing promising first results. Evolutionary algorithms, as guided search approach, find close-to-optimal solutions with respect to some fitness function in an iterative process using biologically motivated mechanisms like selection, mutation and recombination. As such, they provide a powerful alternative to filtering methods commonly used in visualization where the space of possible candidates is densely sampled in a pre-processing step from which the best candidates are selected and visualized. This approach however tends to be increasingly inefficient with growing data size or expensive candidate computations resulting in large pre-processing times. We present an evolutionary algorithm for the problem of streamline selection to highlight features of interest in flow data. Our approach directly optimizes the solution candidates with respect to a user selected fitness function requiring significantly less computations. At the same time the problem of possible under-sampling is solved since we are not tied to a preset resolution. We demonstrate our approach on the well-known flow around an obstacle as case with a two-dimensional search space. The blood flow in an aneurysm serves as an example with a three-dimensional search space. For both, the achieved results are comparable to line filtering approaches with much less line computations.
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| 6. |
- Engelke, Wito, 1983-
(författare)
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Exploring the Invisible : FINDING STRUCTURE IN SCIENTIFIC DATA
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, I present contributions towards the aim of understanding flow-related scientific data sets by communicating relation, properties, and structure. The individual papers are contributions to three different areas. First, real-world visualization challenges with domain specific tasks. The individual applications are ranging from analyzing transport behavior in a centrifugal pump, to visualization of the impact of volcano eruptions and their atmospheric aftermath, and studying circulation dynamics and eddy movements in the ocean currents of the Red Sea. Although the three individual publications target different domains, they share common demands. Furthermore, the experience shows that combining and adapting different visualization techniques to support experts is essential for these scenarios. Second, technical visualization research with a strong focus on geometry-based, interactive, and explorative techniques. In this area a new type of particle system and a novel geometry-based flow visualization technique based on evolutionary algorithms are presented. With both approaches, areas of interest can be highlighted in a semi-automatic fashion by facilitating user-defined importance measures. Lastly, a method for decoupling definition and tracking of features. Here, the development of a fast but flexible method for defining and tracking cyclonic features in pressure fields using a solid and robust mathematical basis is presented. The initial theoretical work is discussed in context of its practical applications by pointing to relevant follow-up publications.The experience from real-world visualization tasks shows that understanding and gaining insight of scientific data with the help of visualization is an interactive, explorative, and non-linear process. Here, different methods must be combined and adapted such that they complement each other. Through this practice, relation, properties, and structure can be revealed, and a mental model can be created.From the real-world visualization challenges and the contributions in research, demands on techniques and their embedding in a visualization toolkit can be derived. Here, the ideal software is flexible, adaptable, and allows for interactive exploration. Furthermore, the process is benefiting from a semi-automatic approach guiding the domain expert during analysis. These aspects are used as guidelines for the implementation and development work associated with the contributions of this thesis and are presented in a dedicated Chapter.
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| 7. |
- Engelke, Wito, 1983-, et al.
(författare)
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Scientific Visualization for Atmospheric Data Analysis in Collaborative Virtual Environments
- 2016
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The three year European research project CROSS DRIVE (Collaborative Rover Operations and Planetary Science Analysis System based on Distributed Remote and Interactive Virtual Environments) started in January 2014. The research and development within this project is motivated by three use case studies: landing site characterization, atmospheric science and rover target selection.Currently the implementation for the second use case is in its final phase. Here, the requirements were generated based on the domain experts input and lead to development and integration of appropriate methods for visualization and analysis of atmospheric data. The methods range from volume rendering, interactive slicing, iso-surface techniques to interactive probing. All visualization methods are integrated in DLR’s Terrain Rendering application. With this, the high resolution surface data visualization can be enriched with additional methods appropriate for atmospheric data sets. This results in an integrated virtual environment where the scientist has the possibility to interactively explore his data sets directly within the correct context. The data sets include volumetric data of the martian atmosphere, precomputed two dimensional maps and vertical profiles. In most cases the surface data as well as the atmospheric data has global coverage and is of time dependent nature. Furthermore, all interaction is synchronized between different connected application instances, allowing for collaborative sessions between distant experts.
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| 8. |
- Engelke, Wito, 1983-, et al.
(författare)
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Scientific Visualization for Space Science Data Analysis in Collaborative Virtual Environments
- 2015
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Ingår i: Proceedings of IEEE SciVis 2015. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- The European research project CROSS DRIVE (Collaborative Rover Operations and Planetary Science Analysis System based on Distributed Remote and Interactive Virtual Environments) aims at developing an innovative collaborative workspace infrastructure enabling re- mote scientific and engineering experts to collectively analyze and interpret combined datasets using shared simulation tools. The three year project started in January 2014 and unites best European expertise in the fields of planetary research and Mars science, Virtual Reality (VR), atmospheric science and research as well as rover mission planning.
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| 9. |
- Engelke, Wito, 1983-, et al.
(författare)
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Topology-Based Feature Design and Tracking for Multi-center Cyclones
- 2021
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Ingår i: Topological Methods in Data Analysis and Visualization VI. - Cham : Springer. - 9783030834999 - 9783030835002 ; , s. 71-85
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Bokkapitel (refereegranskat)abstract
- In this paper, we propose a concept to design, track, and compare application-specific feature definitions expressed as sets of critical points. Our work has been inspired by the observation that in many applications a large variety of different feature definitions for the same concept are used. Often, these definitions compete with each other and it is unclear which definition should be used in which context. A prominent example is the definition of cyclones in climate research. Despite the differences, frequently these feature definitions can be related to topological concepts.
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| 10. |
- Garcia, Arturo S., et al.
(författare)
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A collaborative workspace architecture for strengthening collaboration among space scientists
- 2015
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Ingår i: Proceedings of a meeting held 7-14 March 2015, Big Sky, Montana, USA.. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781479953790 - 9781479953806 - 9781479953776 ; , s. 1133-1144
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Konferensbidrag (refereegranskat)abstract
- Space exploration missions have produced large data of immense value, to both research and the planning and operating of future missions. However, current datasets and simulation tools fragment teamwork, especially across disciplines and geographical location. The aerospace community already exploits virtual reality for purposes including space tele-robotics, interactive 3D visualization, simulation and training. However, collaborative virtual environments are yet to be widely deployed or routinely used in space projects. Advanced immersive and collaborative visualization systems have the potential for enhancing the efficiency and efficacy of data analysis, simplifying visual benchmarking, presentations and discussions. We present preliminary results of the EU funded international project CROSS DRIVE, which develops an infrastructure for collaborative workspaces for space science and missions. The aim is to allow remote scientific and engineering experts to collectively analyze and interpret combined datasets using shared simulation tools. The approach is to combine advanced 3D visualization techniques and interactive tools in conjunction with immersive virtuality telepresence. This will give scientists and engineers the impression of teleportation from their respective buildings across Europe, to stand together on a planetary surface, surrounded by the information and tools that they need. The conceptual architecture and proposed realization of the collaborative workspace are described. ESA's planned ExoMars mission provides the use-case for deriving user requirements and evaluating our implementation.
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