TY - JOUR A1 - Alonso, Sergio A1 - Kähler, Ralf A1 - S. Mikhailov, Alexander A1 - Sagués, Francisco T1 - Expanding scroll rings and negative tension turbulence in a model of excitable media JF - Phys. Rev. E Y1 - 2004 U6 - https://doi.org/10.1103/PhysRevE.70.056201 VL - 70 IS - 5 SP - 056201 PB - American Physical Society ER - TY - CHAP A1 - Hege, Hans-Christian A1 - Hutanu, Andrei A1 - Kähler, Ralf A1 - Merzky, André A1 - Radke, Thomas A1 - Seidel, Edward A1 - Ullmer, Brygg T1 - Progressive Retrieval and Hierarchical Visualization of Large Remote Data T2 - Proceedings of the 2003 Workshop on Adaptive Grid Middleware Y1 - 2003 SP - 60 EP - 72 ER - TY - CHAP A1 - Prohaska, Steffen A1 - Hutanu, Andrei A1 - Kähler, Ralf A1 - Hege, Hans-Christian T1 - Interactive exploration of large remote micro-CT scans T2 - Proc. IEEE Visualization 2004 Y1 - 2004 U6 - https://doi.org/10.1109/VIS.2004.51 SP - 345 EP - 352 CY - Austin, Texas ER - TY - JOUR A1 - Hege, Hans-Christian A1 - Kähler, Ralf A1 - Seidel, Edward A1 - Radke, Thomas T1 - GriKSL zeigt Live-Demos auf der iGrid2002 JF - DFN-Mitteilungen, Heft 60 Y1 - 2002 SP - 21 EP - 22 ER - TY - CHAP A1 - Kähler, Ralf A1 - Cox, Donna A1 - Patterson, Robert A1 - Levy, Stuart A1 - Hege, Hans-Christian A1 - Abel, Tom ED - J. Moorhead, Robert ED - Gross, Markus ED - I. Joy, Kenneth T1 - Rendering The First Star in The Universe - A Case Study T2 - Proceedings of IEEE Visualization 2002 Y1 - 2002 U6 - https://doi.org/10.1109/VISUAL.2002.1183824 SP - 537 EP - 540 PB - IEEE Computer Society Press CY - Boston MA, USA ER - TY - JOUR A1 - Kähler, Ralf A1 - Hege, Hans-Christian T1 - Texture-based volume rendering of adaptive mesh refinement data JF - The Visual Computer Y1 - 2002 VL - 18 IS - 8 SP - 491 EP - 492 ER - TY - JOUR A1 - Kähler, Ralf A1 - Simon, Mark A1 - Hege, Hans-Christian T1 - Interactive Volume Rendering of Large Data Sets Using Adaptive Mesh Refinement Hierarchies JF - IEEE Transactions on Visualization and Computer Graphics Y1 - 2003 U6 - https://doi.org/10.1109/TVCG.2003.1207442 VL - 9 IS - 3 SP - 341 EP - 351 ER - TY - CHAP A1 - Kähler, Ralf A1 - Wise, John A1 - Abel, Tom A1 - Hege, Hans-Christian T1 - A framework for interactive, high-quality volume rendering of cosmological simulations T2 - Proc. Int. Workshop on Volume Graphics (VG06) Y1 - 2006 SP - 103 EP - 110 PB - Eurographics / IEEE VGTC 2006 CY - Boston ER - TY - CHAP A1 - Kähler, Ralf A1 - Abel, Tom A1 - Hege, Hans-Christian T1 - Simultaneous GPU-Assisted Raycasting of Unstructured Point Sets and Volumetric Grid Data T2 - Proceedings of IEEE/EG International Symposium on Volume Graphics 2007 Y1 - 2007 SP - 49 EP - 56 PB - A K Peters CY - Prague, Czech Republic ER - TY - CHAP A1 - Kähler, Ralf A1 - Prohaska, Steffen A1 - Hutanu, Andrei A1 - Hege, Hans-Christian T1 - Visualization of time-dependent remote adaptive mesh refinement data T2 - Proc. IEEE Visualization 2005 Y1 - 2005 U6 - https://doi.org/10.1109/VISUAL.2005.1532793 SP - 175 EP - 182 CY - Minneapolis, USA ER - TY - THES A1 - Kähler, Ralf T1 - Accelerated Volume Rendering on Structured Adaptive Meshes N2 - Multi-scale phenomena are abundant in many application fields. Representing and numerically simulating such processes is a challenging task since quite different scales have to be resolved, which often requires enormous amounts of storage and computational power. An important strategy in this context is adaptivity, i.e. local adjustment of the spatio-temporal resolution to the details to be resolved. A standard representation therefore are hierarchical, locally refined grids. A specific adaptive approach for solving partial differential equations, usually called AMR (Adaptive Mesh Refinement), was introduced in 1984. The basic idea is to combine the simplicity of structured grids and the advantages of local refinement. In this numerical scheme the computations are started on a set of coarse, potentially overlapping structured grids, that cover the computational domain. Local error criteria are applied to detect regions that require higher resolution. These are covered by subgrids with decreasing mesh spacing, which do not replace, but rather overlap the refined regions of the coarser patches. The equations are advanced on the finer subgrids and the refinement procedure recursively continues until all cells fulfill the considered error criteria, giving rise to a hierarchy of nested levels of refinement. In 1989 a variant of this scheme, called Structured Adaptive Mesh Refinement (SAMR), which reduces some of the complexity of the original approach, was proposed. While the separate subgrids in the AMR scheme could be rotated against each other, in SAMR they are aligned with the major axes of the coordinate system, which for example simplifies the computation of fluxes of (conserved) quantities through the cell faces. SAMR has become more and more popular in the last decade, and nowadays it is applied in many domains like hydrodynamics, meteorology and in particular in cosmology and relativistic astrophysics. Due to this growing popularity, an increasing number of scientists is in need of appropriate interactive visualization techniques to interpret and analyze AMR simulation data. Tools for both, 2D analysis to quantitatively convey the information within single slices and 3D representations to apprehend the overall structure are required. In this thesis we develop direct and indirect volume visualization algorithms for scalar fields that are defined on structured Adaptive Mesh Refinement (SAMR) grids. In particular algorithms for planar slicing and the display of height fields, C0-continuous isosurface extraction, software-, and hardware-based direct volume rendering and temporal interpolation for cell-, and vertex-centered data on unrestricted SAMR grids are proposed. Additionally we investigate the applicability of SAMR data structures for accelerated software-, and hardware-based volume rendering of large 3D scalar data. KW - Visualization KW - Volume Rendering KW - Adaptive Mesh Refinement Data Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:188-2005002769 ER -