TY - GEN A1 - Rosanwo, Olufemi A1 - Petz, Christoph A1 - Prohaska, Steffen A1 - Hotz, Ingrid A1 - Hege, Hans-Christian T1 - Dual Streamline Seeding - Method and Implementation N2 - This work introduces a novel streamline seeding technique based on dual streamlines that are orthogonal to the vector field, instead of tangential. The greedy algorithm presented here produces a net of orthogonal streamlines that is iteratively refined resulting in good domain coverage and a high degree of continuity and uniformity. The algorithm is easy to implement and efficient, and it naturally extends to curved surfaces. N2 - In dieser Arbeit wird eine neue Strategie zur Platzierung von Stromlinien vorgestellt. Hierzu werden zusätzliche duale Stromlinien verwendet, die --im Gegensatz zur üblichen Definition-- orthogonal zum Vektorfeld verlaufen. Der vorgestellte Greedy-Algorithmus berechnet ein Netz aus orthogonalen Stromlinien, welches iterativ verfeinert wird, was zu einer guten Abdeckung der Domäne und einer gleichmäßigen Verteilung der Stromlinien führt. Es handelt sich um einen einfach zu implementierenden und effizienten Algorithmus, der direkt auf gekrümmten Oberflächen anwendbar ist. T3 - ZIB-Report - 08-49 Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-11032 SN - 1438-0064 ER - TY - GEN A1 - Grammel, Martin A1 - Hege, Hans-Christian A1 - Wunderling, Roland T1 - On the Impact of Communication Latencies on Distributed Sparse LU Factorization. N2 - Sparse LU factorization offers some potential for parallelism, but at a level of very fine granularity. However, most current distributed memory MIMD architectures have too high communication latencies for exploiting all parallelism available. To cope with this, latencies must be avoided by coarsening the granularity and by message fusion. However, both techniques limit the concurrency, thereby reducing the scalability. In this paper, an implementation of a parallel LU decomposition algorithm for linear programming bases is presented for distributed memory parallel computers with noticable communication latencies. Several design decisions due to latencies, including data distribution and load balancing techniques, are discussed. An approximate performance model is set up for the algorithm, which allows to quantify the impact of latencies on its performance. Finally, experimental results for an Intel iPSC/860 parallel computer are reported and discussed. T3 - ZIB-Report - SC-93-28 Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-1245 ER - TY - JOUR A1 - Lindow, Norbert A1 - Baum, Daniel A1 - Hege, Hans-Christian T1 - Ligand Excluded Surface: A New Type of Molecular Surface JF - IEEE Transactions on Visualization and Computer Graphics N2 - The most popular molecular surface in molecular visualization is the solvent excluded surface (SES). It provides information about the accessibility of a biomolecule for a solvent molecule that is geometrically approximated by a sphere. During a period of almost four decades, the SES has served for many purposes – including visualization, analysis of molecular interactions and the study of cavities in molecular structures. However, if one is interested in the surface that is accessible to a molecule whose shape differs significantly from a sphere, a different concept is necessary. To address this problem, we generalize the definition of the SES by replacing the probe sphere with the full geometry of the ligand defined by the arrangement of its van der Waals spheres. We call the new surface ligand excluded surface (LES) and present an efficient, grid-based algorithm for its computation. Furthermore, we show that this algorithm can also be used to compute molecular cavities that could host the ligand molecule. We provide a detailed description of its implementation on CPU and GPU. Furthermore, we present a performance and convergence analysis and compare the LES for several molecules, using as ligands either water or small organic molecules. Y1 - 2014 U6 - https://doi.org/10.1109/TVCG.2014.2346404 VL - 20 IS - 12 SP - 2486 EP - 2495 ER - TY - GEN A1 - Lindow, Norbert A1 - Baum, Daniel A1 - Hege, Hans-Christian T1 - Ligand Excluded Surface: A New Type of Molecular Surface N2 - The most popular molecular surface in molecular visualization is the solvent excluded surface (SES). It provides information about the accessibility of a biomolecule for a solvent molecule that is geometrically approximated by a sphere. During a period of almost four decades, the SES has served for many purposes – including visualization, analysis of molecular interactions and the study of cavities in molecular structures. However, if one is interested in the surface that is accessible to a molecule whose shape differs significantly from a sphere, a different concept is necessary. To address this problem, we generalize the definition of the SES by replacing the probe sphere with the full geometry of the ligand defined by the arrangement of its van der Waals spheres. We call the new surface ligand excluded surface (LES) and present an efficient, grid-based algorithm for its computation. Furthermore, we show that this algorithm can also be used to compute molecular cavities that could host the ligand molecule. We provide a detailed description of its implementation on CPU and GPU. Furthermore, we present a performance and convergence analysis and compare the LES for several molecules, using as ligands either water or small organic molecules. T3 - ZIB-Report - 14-27 Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-51194 SN - 1438-0064 ER - TY - JOUR A1 - Egger, Robert A1 - Dercksen, Vincent J. A1 - Udvary, Daniel A1 - Hege, Hans-Christian A1 - Oberlaender, Marcel T1 - Generation of dense statistical connectomes from sparse morphological data JF - Frontiers in Neuroanatomy Y1 - 2014 U6 - https://doi.org/10.3389/fnana.2014.00129 VL - 8 IS - 129 ER - TY - CHAP A1 - Klindt, Marco A1 - Prohaska, Steffen A1 - Baum, Daniel A1 - Hege, Hans-Christian ED - Arnold, David ED - Kaminski, Jaime ED - Niccolucci, Franco ED - Stork, Andre T1 - Conveying Archaeological Contexts to Museum Visitors: Case Study Pergamon Exhibition T2 - VAST12: The 13th International Symposium on Virtual Reality, Archaeology and Intelligent Cultural Heritage - Short Papers Y1 - 2012 UR - http://diglib.eg.org/EG/DL/PE/VAST/VAST12S/025-028.pdf U6 - https://doi.org/10.2312/PE/VAST/VAST12S/025-028 SP - 25 EP - 28 PB - Eurographics Association CY - Brighton, UK ER - TY - CHAP A1 - Klindt, Marco A1 - Baum, Daniel A1 - Prohaska, Steffen A1 - Hege, Hans-Christian T1 - iCon.text – a customizable iPad app for kiosk applications in museum exhibitions T2 - EVA 2012 Berlin Y1 - 2012 SP - 150 EP - 155 PB - Gesellschaft zur Förderung angewandter Informatik e.V. CY - Volmerstraße 3, 12489 Berlin ER - TY - CHAP A1 - Lindow, Norbert A1 - Baum, Daniel A1 - Bondar, Ana-Nicoleta A1 - Hege, Hans-Christian T1 - Dynamic Channels in Biomolecular Systems: Path Analysis and Visualization T2 - Proceedings of IEEE Symposium on Biological Data Visualization (biovis’12) Y1 - 2012 U6 - https://doi.org/10.1109/BioVis.2012.6378599 SP - 99 EP - 106 ER - TY - CHAP A1 - Pöthkow, Kai A1 - Hege, Hans-Christian ED - Laidlaw, David ED - Vilanova, Anna T1 - Uncertainty Propagation in DT-MRI Anisotropy Isosurface Extraction T2 - New Developments in the Visualization and Processing of Tensor Fields Y1 - 2012 SP - 209 EP - 225 PB - Springer CY - Berlin ER - TY - GEN A1 - Stalling, Detlev A1 - Westerhoff, Malte A1 - Hege, Hans-Christian ED - Hansen, Charles ED - Johnson, Christopher T1 - Amira: A highly interactive system for visual data analysis T2 - The Visualization Handbook Y1 - 2005 U6 - https://doi.org/10.1016/B978-012387582-2/50040-X SP - 749 EP - 767 PB - Elsevier ER -