Browsing by Author "Evers, Marina"

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    Interactive Visual Analysis of Regional Time Series Correlation in Multi-field Climate Ensembles
    (The Eurographics Association, 2023) Evers, Marina; Böttinger, Michael; Linsen, Lars; Dutta, Soumya; Feige, Kathrin; Rink, Karsten; Zeckzer, Dirk
    Spatio-temporal multi-field data resulting from ensemble simulations are commonly used in climate research to investigate possible climatic developments and their certainty. One analysis goal is the investigation of possible correlations among different spatial regions in the different fields to find regions of related behavior. We propose an interactive visual analysis approach that focuses on the analysis of correlations in spatio-temporal ensemble data. Our approach allows for finding correlations between spatial regions in different fields. Detection of clusters of strongly correlated spatial regions is supported by lower-dimensional embeddings. Then, groups can be selected and investigated in detail, e.g., to study the temporal evolution of the selected group, their Fourier spectra or the distribution of the correlations over the different ensemble members. We apply our approach to selected 2D scalar fields of a large ensemble climate simulation and demonstrate the utility of our tool with several use cases.
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    Studying the Effect of Tissue Properties on Radiofrequency Ablation by Visual Simulation Ensemble Analysis
    (The Eurographics Association, 2022) Heimes, Karl; Evers, Marina; Gerrits, Tim; Gyawali, Sandeep; Sinden, David; Preusser, Tobias; Linsen, Lars; Renata G. Raidou; Björn Sommer; Torsten W. Kuhlen; Michael Krone; Thomas Schultz; Hsiang-Yun Wu
    Radiofrequency ablation is a minimally invasive, needle-based medical treatment to ablate tumors by heating due to absorption of radiofrequency electromagnetic waves. To ensure the complete target volume is destroyed, radiofrequency ablation simulations are required for treatment planning. However, the choice of tissue properties used as parameters during simulation induce a high uncertainty, as the tissue properties are strongly patient-dependent. To capture this uncertainty, a simulation ensemble can be created. Understanding the dependency of the simulation outcome on the input parameters helps to create improved simulation ensembles by focusing on the main sources of uncertainty and, thus, reducing computation costs. We present an interactive visual analysis tool for radiofrequency ablation simulation ensembles to target this objective. Spatial 2D and 3D visualizations allow for the comparison of ablation results of individual simulation runs and for the quantification of differences. Simulation runs can be interactively selected based on a parallel coordinates visualization of the parameter space. A 3D parameter space visualization allows for the analysis of the ablation outcome when altering a selected tissue property for the three tissue types involved in the ablation process. We discuss our approach with domain experts working on the development of new simulation models and demonstrate the usefulness of our approach for analyzing the influence of different tissue properties on radiofrequency ablations.