02309nas a2200145 4500008004100000245012600041210006900167520177600236100002302012700002202035700002102057700002302078700002202101856004002123 2009 eng d00aFAnToM - Lessons Learned from Design, Implementation, Administration, and Use of a Visualization System for Over 10 Years0 aFAnToM Lessons Learned from Design Implementation Administration3 aScientific visualization has become a central tool in many research areas since it has been established as a research discipline in 1987 [2]. Naturally, this development resulted in software tools specifically tailored for the visualization task at hand. While many such tools exist, the design choices underlying them vary greatly. This abstract describes some aspects of the FAnToM1 visualization system that is being developed since 1999. Initially created to support research in topological methods for vector and tensor fields, the system quickly grew into a visualization platform for general flow visualization specialized to data represented on unstructured grids. From this origin, FAnToM derives advanced data structures for point location and interpolation over unstructured meshes, as well as fast integral curve capabilities. More recently, FAnToM has gradually been extended to serve a wider area of visualization applications, including medical and graph visualization. Throughout the development of FAnToM, close collaboration with application domain scientists has been a strong priority to facilitate the system s usefulness on state-of-the-art problems. The continuous development of this system over a period of ten years revealed a number of important aspects that are crucial for the usefulness of a visualization system. Furthermore, some design choices underlying FAnToM are uncommon among visualization systems in general. Here, it is our aim to discuss some aspects and design choices underlying the FAnToM system to illustrate some of its properties and differences from other visualization systems. During the discussion, we will point out some experiences and lessons learned in working with the system on modern visualization applications.1 aScheuermann, Gerik1 aWiebel, Alexander1 aGarth, Christoph1 aHlawitschka, Mario1 aWischgoll, Thomas uhttp://knoesis.wright.edu/node/235101421nas a2200145 4500008004100000245007500041210006900116300001000185520095300195100002301148700002201171700002001193700002201213856004001235 2008 eng d00aThe State of the Art in Flow Visualization: Structure-Based Techniques0 aState of the Art in Flow Visualization StructureBased Techniques a74-913 aThe analysis of morphometric data of the vasculature of any organ requires appropriate visualization methods to be applied due to the vast number of vessels that can be present in such data. In addition, the geometric properties of vessel segments, i.e. being rather long and thin, can make it difficult to judge on relative position, despite depth cues such as proper lighting and shading of the vessels. Virtual environments that provide true 3-D visualization of the data can help enhance the visual perception. Ideally, the system should be relatively cost-effective. Hence, this paper describes a Linux-based virtual environment that utilizes a 50 inch plasma screen as its main display. The overall cost of the entire system is less than $3,500 which is considerably less than other commercial systems. The system was successfully used for visualizing vascular data sets providing true three-dimensional perception of the morphometric data.
1 aScheuermann, Gerik1 aSalzbrunn, Tobias1 aJaenicke, Heike1 aWischgoll, Thomas uhttp://knoesis.wright.edu/node/238600338nas a2200097 4500008004100000245005700041210005700098100002300155700002200178856004000200 2003 eng d00a3D Loop Detection and Visualization in Vector Fields0 a3D Loop Detection and Visualization in Vector Fields1 aScheuermann, Gerik1 aWischgoll, Thomas uhttp://knoesis.wright.edu/node/242700983nas a2200169 4500008004100000022001800041245006500059210006300124260002100187300001200208520044100220100002300661700002300684700002100707700002200728856006300750 2003 eng d a981-238-317-400aEvolution of Topology in Axi-Symmetric and 3-D Viscous Flows0 aEvolution of Topology in AxiSymmetric and 3D Viscous Flows bWorld Scientific a622-6433 aTopological methods are used to establish global and to extract local structure properties of vector fields in axi-symmetric and 3-d flows as function of time. The notion of topological skeleton is applied to the interpretation of vector fields generated numerically by the Navier-Stokes equations. The flows considered are swirling jets with super-critical swirl numbers that show low Reynolds number turbulence in the break-up region.1 aScheuermann, Gerik1 aKollmann, Wolfgang1 aTricoche, Xavier1 aWischgoll, Thomas uhttp://knoesis.wright.edu/library/resource.php%3Fid%3D209201952nas a2200193 4500008004100000245007000041210006900111300001200180520137800192653001201570653001801582653001301600653002701613653001601640653001701656100002301673700002201696856004001718 2003 eng d00aParallel Computation of the Topological Skeleton of Vector Fields0 aParallel Computation of the Topological Skeleton of Vector Field a139-1443 aVector fields occur in many of the problems in science and engineering. In combustion processes, for instance, vector fields describe the flow of the gas. This process can be enhanced using vector field visualization techniques. Also, wind tunnel experiments can be analyzed. An example is the design of an air wing. The wing can be optimized to create a smoother flow around it. To analyze such kind of datasets topological methods that clearly show the whole structure of the vector field in one picture are a very good tool. During the last years, many extensions were proposed for this method. In addition to standard topological methods we also detect closed streamlines since they are a topological feature that completes the topological analysis. To accelerate the computation of such a topological analysis we developed a parallel method to reduce computational time. Therefore, we spread the computation of the separatrices of the topological skeleton to clients of a computer cluster. To test our implementation we use a numerical simulation of a swirling jet with an inflow into a steady medium. We built two different Linux clusters as parallel test systems where we check the performance increase when adding more processors to the cluster. We show that we have a very low parallel overhead due to the neglectable communication expense of our implementation.
10a2D flow10aLinux cluster10aparallel10astreamline computation10astreamlines10avector field1 aScheuermann, Gerik1 aWischgoll, Thomas uhttp://knoesis.wright.edu/node/239200896nas a2200133 4500008004100000245006500041210006300106520044100169100002300610700002300633700002100656700002200677856006300699 2002 eng d00aEvolution of Topology in Axi-Symmetric and 3-D Viscous Flows0 aEvolution of Topology in AxiSymmetric and 3D Viscous Flows3 aTopological methods are used to establish global and to extract local structure properties of vector fields in axi-symmetric and 3-d flows as function of time. The notion of topological skeleton is applied to the interpretation of vector fields generated numerically by the Navier-Stokes equations. The flows considered are swirling jets with super-critical swirl numbers that show low Reynolds number turbulence in the break-up region.1 aScheuermann, Gerik1 aKollmann, Wolfgang1 aTricoche, Xavier1 aWischgoll, Thomas uhttp://knoesis.wright.edu/library/resource.php%3Fid%3D209200959nas a2200121 4500008004100000245005200041210005200093300001200145520059500157100002300752700002200775856004000797 2002 eng d00aLocating Closed Streamlines in 3D Vector Fields0 aLocating Closed Streamlines in 3D Vector Fields a227-2323 aThe analysis and visualization of flows is a central problem in visualization. Topology based methods have gained increasing interest in recent years. This article describes a method for the detection of closed streamlines in 3D flows. It is based on a special treatment of cases where a streamline reenters a cell to prevent infinite cycling during streamline calculation. The algorithm checks for possible exits of a loop of crossed faces and detects structurally stable closed streamlines. These global features are not detected by conventional topology and feature detection algorithms.1 aScheuermann, Gerik1 aWischgoll, Thomas uhttp://knoesis.wright.edu/node/239500991nas a2200145 4500008004100000245008400041210006900125300001200194520051700206100002300723700002100746700001600767700002200783856004000805 2002 eng d00aTopology Tracking for the Visualization of Time-Dependent Two-Dimensional Flows0 aTopology Tracking for the Visualization of TimeDependent TwoDime a249-2583 aThe paper presents a topology-based visualization method for time-dependent two-dimensional vector fields. A time interpolation enables the accurate tracking of critical points and closed orbits as well as the detection and identification of structural changes. This completely characterizes the topology of the unsteady flow. Bifurcation theory provides the theoretical framework. The results are conveyed by surfaces that separate subvolumes of uniform flow behavior in a three-dimensional space-time domain.
1 aScheuermann, Gerik1 aTricoche, Xavier1 aHagen, Hans1 aWischgoll, Thomas uhttp://knoesis.wright.edu/node/237900974nas a2200121 4500008004100000245006100041210006100102300001200163520059200175100002300767700002200790856004000812 2001 eng d00aDetection and Visualization of Planar Closed Streamlines0 aDetection and Visualization of Planar Closed Streamlines a165-1723 aThe analysis and visualization of flows is a central problem in visualization. Topology based methods have gained increasing interest in recent years. This article describes a method for the detection of closed streamlines in flows. It is based on a special treatment of cases where a streamline reenters a cell to prevent infinite cycling during streamline calculation. The algorithm checks for possible exits of a loop of crossed edges and detects structurally stable closed streamlines. These global features are not detected by conventional topology and feature detection algorithms.1 aScheuermann, Gerik1 aWischgoll, Thomas uhttp://knoesis.wright.edu/node/238001045nas a2200133 4500008004100000245005700041210005700098300006100155520059400216100002200810700002300832700001600855856004000871 2001 eng d00aDistributed Computation of Planar Closed Streamlines0 aDistributed Computation of Planar Closed Streamlines aIEEE Transactions on Visualization and Computer Graphics3 aThe analysis and visualization of flows is a central problem in visualization. Topology based methods have gained increasing interest in recent years. This article describes a method for the detection of closed streamlines in flows. It is based on a special treatment of cases where a streamline reenters a cell to prevent infinite cycling during streamline calculation. The algorithm checks for possible exits of a loop of crossed edges and detects structurally stable closed streamlines. These global features are not detected by conventional topology and feature detection algorithms.
1 aWischgoll, Thomas1 aScheuermann, Gerik1 aHagen, Hans uhttp://knoesis.wright.edu/node/238901607nas a2200217 4500008004100000245006100041210006100102300001000163520099000173653001201163653002201175653001601197653001801213653001301231653002701244653001701271100002301288700001601311700002201327856004001349 2001 eng d00aParallel Detection of Closed Streamlines in Planar Flows0 aParallel Detection of Closed Streamlines in Planar Flows a84-883 aClosed streamlines are an integral part of vector field topology, since they behave like sources respectively sinks but are often neither considered nor detected. If a streamline computation makes too many steps or takes too long, the computation is usually terminated without any answer on the final behavior of the streamline. We developed an algorithm that detects closed streamlines during the integration process. Since the detection of all closed streamlines in a vector field requires the computation of many streamlines we extend this algorithm to a parallel version to enhance computational speed. To test our implementation we use a numerical simulation of a swirling jet with an inflow into a steady medium. We built two different Linux clusters as parallel test systems where we check the performance increase when adding more processors to the cluster. We show that we have a very low parallel overhead due to the neglectable communication expense of our implementation.
10a2D flow10aclosed streamline10alimit cycle10aLinux cluster10aparallel10astreamline computation10avector field1 aScheuermann, Gerik1 aHagen, Hans1 aWischgoll, Thomas uhttp://knoesis.wright.edu/node/239101210nas a2200133 4500008004100000245006300041210006200104300001200166520079700178100002300975700001600998700002201014856004001036 2001 eng d00aTracking Closed Streamlines in Time-Dependent Planar Flows0 aTracking Closed Streamlines in TimeDependent Planar Flows a447-4543 aClosed streamlines are a missing part in most visualizations of vector field topology. In this paper, we propose a method which detects closed streamlines in a time-dependent two-dimensional flow and investigates the behavior of these closed streamlines over time. We search in all timesteps for closed streamlines and connect them to each other in temporal order to get a tube shaped visualization. As a starting point for our investigation we look for changes of the type of critical points that lead to the creation or vanishing of closed streamlines (Hopf bifurcation). We follow the resulting limit cycle over time. In addition, changes of the topological skeleton, built by critical points and separatrices, are considered which may start or terminate the life of a closed streamline.
1 aScheuermann, Gerik1 aHagen, Hans1 aWischgoll, Thomas uhttp://knoesis.wright.edu/node/239001108nas a2200181 4500008004100000245004000041210004000081300001100121520059600132653001600728653003000744653003000774653002100804100002300825700001600848700002200864856004000886 1999 eng d00aVisualization of Temporal Distances0 aVisualization of Temporal Distances a 43-463 aIn order to visualize temporal distances, i.e. the time for traveling from one place to another, we arrange some selected cities according to these distances. In this way, the new positions reflect the connectivity of these cities with respect to time. Unlike existing approaches using tables, our method facilitates a global examination of the connectivity of a whole country. For the database, any connectivity information can be used as long as it is ensured that it is unambiguous. Therefore, any transport system can be considered and even a mixture of such systems could be visualized.10adeformation10aInformation Visualization10aphysically based modeling10atransport system1 aScheuermann, Gerik1 aHagen, Hans1 aWischgoll, Thomas uhttp://knoesis.wright.edu/node/2282