TY - GEN A1 - Best, Christoph A1 - Hege, Hans-Christian T1 - Visualizing conformations in molecular dynamics N2 - The Monte Carlo simulation of the dynamics of complex molecules produces trajectories with a large number of different configurations to sample configuration space. It is expected that these configurations can be classified into a small number of conformations representing essential changes in the shape of the molecule. We present a method to visualize these conformations by point sets in the plane based on a geometrical distance measure between individual configurations. It turns out that different conformations appear as well-separated point sets. The method is further improved by performing a cluster analysis of the data set. The point-cluster representation is used to control a three-dimensional molecule viewer application to show individual configurations and conformational changes. The extraction of essential coordinates and visualization of molecular shape is discussed. T3 - ZIB-Report - SC-98-42 KW - Molecular Dynamics KW - Conformations KW - Visualization KW - Cluster Analysis Y1 - 1998 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-3859 ER - TY - GEN A1 - Kähler, Ralf A1 - Hege, Hans-Christian T1 - Visualization of Time-Dependent Adaptive Mesh Refinement Data N2 - Analysis of phenomena that simultaneously occur on quite different spatial and temporal scales require adaptive, hierarchical schemes to reduce computational and storage demands. For data represented as grid functions, the key are adaptive, hierarchical, time-dependent grids that resolve spatio-temporal details without too much redundancy. Here, so-called AMR grids gain increasing popularity. For visualization and feature identification/tracking, the underlying continuous function has to be faithfully reconstructed by spatial and temporal interpolation. Well designed interpolation methods yield better results and help to reduce the amount of data to be stored. We address the problem of temporal interpolation of AMR grid data, e.g.\ for creation of smooth animations or feature tracking. Intermediate grid hierarchies are generated by merging the cells on all refinement levels that are present in the key frames considered. Utilizing a clustering algorithm a structure of nested grids is induced on the resulting collection of cells. The grid functions are mapped to the intermediate hierarchy, thus allowing application of appropriate interpolation techniques. T3 - ZIB-Report - 03-16 KW - AMR KW - non-conforming hexahedral grids KW - multi-resolution techniques Y1 - 2003 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-7384 ER - TY - GEN A1 - Benger, Werner A1 - Hege, Hans-Christian T1 - Tensor Splats N2 - An improved general-purpose technique for the visualization of symmetric positive definite tensor fields of rank two is described. It is based on a splatting technique that is built from tiny transparent glyph primitives which are capable to incorporate the full directional information content of a tensor. The result is an information-rich image that allows to read off the preferred directions in a tensor field at each point of a three-dimensional volume or two-dimensional surface. It is useful for analyzing slices or volumes of a three-dimensional tensor field and can be overlayed with standard volume rendering or color mapping. The application of the rendering technique is demonstrated on general relativistic data and the diffusion tensor field of a human brain. T3 - ZIB-Report - 03-17 KW - tensor field visualization KW - metric KW - splatting KW - volume rendering KW - general relativity KW - diffusion tensor images Y1 - 2003 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-7393 ER - TY - GEN 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 N2 - \noindent The size of data sets produced on remote supercomputer facilities frequently exceeds the processing capabilities of local visualization workstations. This phenomenon increasingly limits scientists when analyzing results of large-scale scientific simulations. That problem gets even more prominent in scientific collaborations, spanning large virtual organizations, working on common shared sets of data distributed in Grid environments. In the visualization community, this problem is addressed by distributing the visualization pipeline. In particular, early stages of the pipeline are executed on resources closer to the initial (remote) locations of the data sets. \noindent This paper presents an efficient technique for placing the first two stages of the visualization pipeline (data access and data filter) onto remote resources. This is realized by exploiting the ``extended retrieve'' feature of GridFTP for flexible, high performance access to very large HDF5 files. We reduce the number of network transactions for filtering operations by utilizing a server side data processing plugin, and hence reduce latency overhead compared to GridFTP partial file access. The paper further describes the application of hierarchical rendering techniques on remote uniform data sets, which make use of the remote data filtering stage. T3 - ZIB-Report - 03-40 KW - remote data access KW - large files KW - visualization pipeline KW - hdf5 KW - grid Y1 - 2003 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-7623 ER - TY - GEN A1 - Baumann, Wolfgang A1 - Hege, Hans-Christian A1 - Schwarz, Uwe A1 - Stüben, Hinnerk T1 - Netzverteilte Visualisierung und Simulation N2 - Dieser Bericht beschreibt die Ergebnisse eines Anwendungsprojektes, das parallel zum Aufbau des Berliner Hochgeschwindigkeitsdatennetzes (Berlin Regional Testbed) am ZIB durchgeführt wurde. Es werden allgemeine Werkzeuge und anwendungsspezifische Arbeitsumgebungen zur netzverteilten Visualisierung und Simulation vorgestellt. Die allgemeinen Werkzeuge unterstützen folgende Aufgaben: Kopplung von Simulationen auf (Hochleistungs-)Rechnern an lokale Grafikarbeitsplätze, objektorientierte und verteilte Visualisierung, Remote-Videoaufzeichnung, Bilddatenkompression und digitaler Filmschnitt. Die spezifischen Arbeitsumgebungen wurden für Aufgaben aus den Bereichen Numerische Mathematik, Astrophysik, Strukturforschung, Chemie, Polymerphysik und Strömungsmechanik entwickelt. T3 - ZIB-Report - TR–96–08 Y1 - 1996 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-5379 ER - TY - GEN A1 - Deuflhard, Peter A1 - Hege, Hans-Christian A1 - Sedlmayr(ed.), E. T1 - Scientific Computing in der Theoretischen Physik. Collected Abstracts. N2 - Die von der DMV-Fachgruppe Scientific Computing in Kooperation mit dem gleichnamigen GAMM-Fachausschuss organisierte Tagung \glqq Scientific Computing in der Theoretischen Physik\grqq~fand vom 16. - 18. März 1994 am Fachbereich Mathematik und Informatik der Freien Universität Berlin statt. Ziel des Workshops war, die Kontakte zwischen den Fachleuten der Gebiete {\em Computational Physics} und {\em Scientific Computing} zu intensivieren. Schwerpunkte des Workshops waren numerische Simulation von Transportmodellen der Astrophysik und Halbleiterphysik, Multilevel-Methoden für partielle Differentialgleichungen sowie Monte-Carlo-Methoden und molekulardynamische Verfahren für Probleme der Statistischen Physik und Quantenfeldtheorie. Der Workshop fand ein äusserst positives Echo und führte über 70 Teilnehmer der verschiedenen Teilgebiete der Theoretischen Physik und ca. 50 Teilnehmer aus dem Bereich der Numerischen Mathematik zusammen. \originalTeX T3 - ZIB-Report - TR-94-01 Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-5068 ER - TY - GEN A1 - Deuflhard, Peter A1 - Hege, Hans-Christian A1 - Seebass, Martin T1 - Progress Towards a Combined MRI/Hyperthermia System N2 - Regional hyperthermia, a clinical cancer therapy, is the main topic of the Sonderforschungsbereich Hyperthermia: Scientific Methods and Clinical Applications'' at Berlin. In recent years, technological improvements towards a better concentration of heat to the desired target region have been achieved. These include a rather sophisticated integrated software environment for therapy planning and a new hyperthermia applicator. In a next step, a detailed closed loop monitoring of the actual treatment is to be developed. For this purpose the hyperthermia applicator is combined with an MRI system, which will allow to check the positioning of the patients and to measure individual blood perfusion as well as the 3D temperature distribution. The measurements will then be employed for an on-line control of the whole treatment. In this intended setting, new fast feedback control algorithms will come into play. T3 - ZIB-Report - 00-07 KW - hyperthermia KW - medical therapy planning KW - applicator design KW - interventional MRI Y1 - 2000 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-5755 ER - TY - GEN A1 - Hege, Hans-Christian A1 - Höllerer, Tobias A1 - Stalling, Detlev T1 - Volume Rendering - Mathematicals Models and Algorithmic Aspects. N2 - In this paper various algorithms for rendering gaseous phenomena are reviewed. In computer graphics such algorithms are used to model natural scenes containing clouds, fog, flames and so on. On the other hand it has become an important technique in scientific visualization to display three dimensional scalar datasets as cloudy objects. Our emphasis is on this latter subject of so-called {\em direct volume rendering}. All algorithms will be discussed within the framework of linear transport theory. The equation of transfer is derived. This equation is suitable to describe the radiation field in a participating medium where absorption, emission, and scattering of light can occur. Almost all volume rendering algorithms can be shown to solve special cases of the equation of transfer. Related problems like the mapping from data values to model parameters or possible parallelization strategies will be discussed as well. T3 - ZIB-Report - TR-93-07 Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-4994 ER - TY - GEN A1 - Hege, Hans-Christian A1 - Polthier, Konrad T1 - Visualization and Mathematics '97 N2 - This report contains paper abstracts of the workshop "Visualization and Mathematics" held in Berlin-Dahlem in September 1997. The meeting serves as a forum for an international community of researchers and practitioners on the application of visualization techniques in mathematics and on mathematical concepts in visualization. It is the second symposium in a series of workshops bringing together mathematicians and experts from scientific visualization. The themes of the workshop include: \begin{itemize} \item - applications in differential geometry and partial differential equations \item - algorithmic aspects of adaptive and hierarchical techniques in space and time \item - time control of animated objects and corresponding algorithms \item - algorithmic representation of objects for display, storage and exchange \item - new visualization techniques for mathematical structures \item - integration of visualization with symbolic and numerical computation. \end{itemize} T3 - ZIB-Report - TR-97-06 Y1 - 1997 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-5480 ER - TY - GEN A1 - Hege, Hans-Christian A1 - Polthier, Konrad T1 - Visualization and Mathematics. International Workshop N2 - International Workshop with support of the Deutsche Forschungsgemeinschaft (DFG) and Max-Planck-Gesellschaft (MPG) Berlin (Dahlem), Germany, May 30 - June 2, 1995 T3 - ZIB-Report - TR-95-02 Y1 - 1995 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-5179 ER -