GLOBUS A. C. L., LASINSKI T.: A tool for visualizing the topology of three-dimensional vector fields. In Proceedings Visualization '91 (91), pp. 33--40.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....results. We list a number of these errors: # The step in which computational errors have the greatest consequences to the correctness of the technique is the trajectory integration. Computing trajectories is error prone due to the instability of the integration process near critical points, [5]. Instabilities even occurred using an adaptive fourth order Runge Kutta method where the timestep was based on the length of the computed segment. Stable adaptive integration has been addressed by also reducing the time step when the angle of the computed segment with respect the the previous ....

A. Globus, C. Levit, and T. Lasinski. A tool for visualizing the topology of three-dimensional vector fields. In G.M. Nielson and L.J. Rosenblum, editors, Proceedings Visualization '91, pages 33--40. IEEE Computer Society Press, Los Alamitos (CA), 1991.

....The result of this approach is a parsimonious display of the important features in the tensor field at the same time showing the continuity (and discontinuities) in the field. Topological tensor field visualization is a direct extension from topological vector field visualization [11, 17, 1]. While this class of methods draws the user s attention to the salient features in the field, the user still has to mentally reconstruct the rest of the field around these degenerate and critical points and skeletons. Focal surfaces and characteristic curves Hagen [14] proposes the use of ....

Al Globus, Creon Levit, and Tom Lasinski. A tool for visualizing the topology of three-dimensional vector fields. In Proceedings: Visualization '91, pages 33 -- 40. IEEE Computer Society, 1991.

....of the numerical gradients of solution variables [22, 23, 25, 38] and are generally e#ective for locating features that can be adequately described by magnitude changes in scalar fields. Critical points define the structural topology of vector fields and provide a convenient method of analysis [10, 20, 36]. However, fluid dynamists are typically interested in macroscopic features, such as vortices, rather than the location of discrete critical points. Significant progress has been made in the area of identifying vortices, or regions of swirling flow [2, 4, 27, 33, 39] The consideration of ....

A. Globus, C. Levit, and T. Lansinski. A Tool for Visualizing the Topology of Three-Dimensional Vector Fields. In IEEE Visualization '91, pages 33-- 39, October 1991.

....seconds to render 130 time steps. The rendering algorithm without the differential algorithm needed approximately 2.45 x 130 = 318.5 seconds. Our algorithm for rendering both Time Changed Regular Ray Diff. Ray Casting Step Elements Casting Time Pct. 0 100 2.245 2.245 100 20 1.82 2.245 0. 23 10.24 40 2.45 2.248 0.28 16.27 60 1.46 2.239 0.19 8.48 80 0.20 2.241 0.08 3.56 100 0.04 2.241 0.04 1.78 120 0.005 2.246 0.02 0.89 Table 4: Rendering time(in seconds) at selected time steps using both the regular and the differential ray casting algorithms: laminar flow simulation ....

....algorithm without the differential algorithm needed approximately 2.45 x 130 = 318.5 seconds. Our algorithm for rendering both Time Changed Regular Ray Diff. Ray Casting Step Elements Casting Time Pct. 0 100 2.245 2.245 100 20 1.82 2.245 0.23 10.24 40 2.45 2.248 0.28 16.27 60 1.46 2. 239 0.19 8.48 80 0.20 2.241 0.08 3.56 100 0.04 2.241 0.04 1.78 120 0.005 2.246 0.02 0.89 Table 4: Rendering time(in seconds) at selected time steps using both the regular and the differential ray casting algorithms: laminar flow simulation data Time Changed Differential Ray Casting Step ....

[Article contains additional citation context not shown here]

A. Globus C. Levit and T. Lasinski. A tool for visualizing the topology of three dimensional vector fields. In Proceedings of Visualization '91, pages 33-40. IEEE Computer Society Press, Los Alamitos, CA, 1991.

.... Coordinated Modeling Center (CCMC) BATS R US is a 3D magnetohydrodynamics (MHD) code developed at the University of Michigan for massively parallel computers using adaptive mesh refinement (AMR) 1] Critical point analysis is an important technique utilized in vector field visualization [2, 3, 4, 5]. Critical points are points at which the magnitude of the vector field vanishes and can used to accurately represent the important aspects of the vector field topology. Recently Wong et al. 6] proposed a vorticity based filtering technique to eliminate less interesting and sometimes ....

A. Globus, C. Levit, and T. Lasinski. A tool for visualizing the topology of three-dimensional vector fields. In Proceedings of Visualization '91, pages 33-40, 408.

....from BATS R US is stored in the HDF5 [15] format in a manner similar to ChomboVis [6] In the next section, we describe a method for vector field visualization of 3D AMR data. 3. Visualization Strategy Critical point analysis is an important technique utilized in vector field visualization [2, 3, 5, 9, 10, 12, 13]. Critical points are points at which the magnitude of the vector field vanishes and can used to accurately represent the important aspects of the vector field topology. Parnell et al. 8] provides the physical theoretical structure of magnetic neutral points. SWX uses OpenDX [14] for ....

....Each leaf in the AMR grid contains an n x xn y xn z block of 3D magnetic field data. A list of candidate critical points is compiled by check ing each leaf in the AMR grid to see whether or not it could contain a critical point. We use the same check as the Flow Analysis Software Toolkit (FAST) [2]. Once it is determined that a block could contain a critical point, the center of the block is used as the initial estimate of the critical point location. The location of the critical point is more precisely determined using Newton s globally convergent method of solving a system of nonlinear ....

A. Globus, C. Levit, and T. Lasinski. A tool for visualizing the topology of three-dimensional vector fields. In Proceedings of Visualization '91, pages 33-40, 408.

....passing the polygons to the geometry pipeline in a back to front order. Research into the display of three dimensional flow has also been explored over the past few years. Various algorithms to represent the flow via ribbons have been developed. Helman and Hesselink [Helman91] and Globus et al. [Globus91] have developed algorithms to display critical points within the flow field. These algorithms and the standard vector or hedgehog plots have no direct way of being combined with the direct volume visualization methods recently developed. Particle systems [Reeves85] can be used to represent both ....

Globus, A. and C. Levit and T. Lasinski. A Tool for Visualizing the Topology of Three-Dimensional Vector Fields. In Proceedings Visualization '91. Gregory Nielson and Larry Rosenblum eds., IEEE Los Alamitos, CA, pp.33--40.

....of the topological structure for flow data originating in flow simulation. Fixed points, detachment attachment points, separatrices, etc. are visualized. Also, the information obtained from the analysis of the Jacobian matrix at fixed points is used for visualization. Also in 1991, Globus et al. [7] developed a tool to identify topological elements within data which is specified on grids. In 1996, Rumpf and Happe [24] as well as Post et al. in 1995 [21] used icons for visualizing local flow characteristics, whereas in 1993 de Leeuw and van Wijk [6] used glyphs to do so. More literature has ....

A. Globus, C. Levit, and T. Lasinski. A tool for visualizing the topology of threedimensional vector fields. In Proc. of IEEE Visualization '91, pages 33--40, October 1991.

....and analysis. They are used as local model for the visualization and allow general positions and arbitrary Poincare indices of the critical points in the interesting regions. 1 INTRODUCTION There is a growing interest in vector field visualization based on topology in the last years ( Helm91] [Glob91]) But all methods so far begin with linear or bilinear interpolation of the grid data and start the analysis of the topology from there. This is a fast algorithm and one receives good results as long as the critical points are well separated and of simple type. But this is often not the case and ....

Globus, A., Levit, C., Lasinski, T.: A Tool for Visualizing the Topology of Three-Dimensional Vector Fields, IEEE Visualization '91, Proc., pp. 33--40, 1991.

....the geometry of the topological structure for flow data originating in flow simulation. Fixed points, detachment attachment points, separatrices, etc. are visualized. Also, the information obtained from the analysis of the Jacobian matrix at fixed points is used for visualization. Globus et at. [8] developed a tool to identify topological elements within data which is specified on grids. Rumpf and Happe [24] as well as Post et al. 22] use icons for visualizing local flow characteristics, whereas de Leeuw and van Wijk [7] use glyphs to do so. More literature is reviewed by Levit [12] and ....

A. Globus, C. Levit, and T. Lasinski. A tool for visualizing the topology of three-dimensional vector fields. In Proc. of IEEE Visualization '91, pages 33--40, October 1991.

....results. We list a number of these errors: ffl The step in which computational errors have the greatest consequences to the correctness of the technique is the trajectory integration. Computing trajectories is error prone due to the instability of the integration process near critical points, [5]. Instabilities even occurred using an adaptive fourth order Runge Kutta method where the timestep was based on the length of the computed segment. Stable adaptive integration has been addressed by also reducing the time step when the angle of the computed segment with respect the the previous ....

A. Globus, C. Levit, and T. Lasinski. A tool for visualizing the topology of three-dimensional vector fields. In G.M. Nielson and L.J. Rosenblum, editors, Proceedings Visualization '91, pages 33--40. IEEE Computer Society Press, Los Alamitos (CA), 1991.

....example, when the location of the cutting plane remains constant (but the scalar field changes) the vertices and the interpolation factors needed don t change. Interpolation: Design benchmarks to test interpolation time and precision, including non linear interpolation. Vector field topology [HELM91, GLOB91]: Place critical points in grid cells with grid singularities. Place critical points on computational boundaries. These ideas are offered as initial suggestions, not final solutions. There are certainly other needs for other applications, and there are probably additional or even better tests ....

A. Globus, C. Levit, T. Lasinski, "A Tool for Visualizing the Topology of Three-Dimensional Vector Fields," Proc.Visualization `91, IEEE Computer Society, San Diego, CA (1991).

No context found.

GLOBUS A. C. L., LASINSKI T.: A tool for visualizing the topology of three-dimensional vector fields. In Proceedings Visualization '91 (91), pp. 33--40.

No context found.

Globus, A., Levit, C., Lasinski, T.: A tool for visualizing the topology of threedimensional vector fields, In Proc. IEEE Visualization 91, 33-40 (1991)

No context found.

A. Globus, C. Levit, and T. Lasinski. A tool for visualizing the topology of three-dimensional vector fields. In Visualization '91, pages 33--40, 1991.

No context found.

A. Globus, Levit, and T. Lasinski. Tool for visualizing the topology of three-dimensional vector fields. In IEEE Visualization, pages 33--40, 1991.

No context found.

A. Globus, C. Levit, and T. Lasinski. A tool for visualizing the topology of three-dimensional vector fields. In Visualization '91, pages 33--40, 1991.

No context found.

GLOBUS, A., LEVIT, C., AND LASINSKI,T. A Tool for Visualizing the Topology of Three-Dimensional Vector Fields. In Proceedings of IEEE Visualization (1991), pp.33--40.

No context found.

Globus, A., C. Levit and T. Lasinski, "A Tool for Visualizing the Topology of Three-Dimensional Vector Fields," Proceedings Visualization '91, San Diego, California, October 22-- 25, pp. 33--40.

No context found.

Al Globus, Creon Levit, and Tom Lasinski. A tool for visualizing the topology of three-dimensional vector fields. In Proceedings: Visualization '91, pages 33 -- 40. IEEE Computer Society, 1991.

No context found.

A. Globus, C. Levit, and T. Lasinski. A tool for visualizing the topology of threedimensional vector fields. In G.M. Nielson and L.J. Rosenblum, editors, Proceedings Visualization '91, pages 33--40. IEEE Computer Society Press, Los Alamitos (CA), 1991.

No context found.

A. Globus, C. Levit, and T. Lasinski. A tool for visualizing the topology of threedimensional vector #elds. In G.M. Nielson and L.J. Rosenblum, editors, Proceedings Visualization '91, pages 33#40. IEEE Computer Society Press, Los Alamitos #CA#, 1991.

No context found.

A. Globus, C. Levit, and T. Lasinski. A Tool for Visualizing the Topology of Three-Dimensional Vector Fields. IEEE Visualization 1991.

No context found.

Al Globus, Creon Levit, and Thomas Lasinski. A tool for visualizing the topology of three-dimensional vector fields. In Visualization '91, pages 33--40, 1991. 15

No context found.

A. Globus, C. Levit and T. Lasinski. A Tool for Visualizing the Topology of Three-Dimensional Vector Fields. Proceedings of IEEE Visualization '91, 1991.

First 50 documents

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC