parallel Coordinates are a powerful method for visualizing multidimensional data but, when applied to largedata sets, they become cluttered and difficult to read. Star Glyphs, on the other hand, can be used to displa...
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ISBN:
(纸本)078039464X
parallel Coordinates are a powerful method for visualizing multidimensional data but, when applied to largedata sets, they become cluttered and difficult to read. Star Glyphs, on the other hand, can be used to display either the attributes of a data item or the values across all items for a single attribute. Star Glyphs may readily provide a quick impression;however, since the full data set will require multiple glyphs, overall readings are more difficult. We present parallel Glyphs, an interactive integration of the visual representations of parallel Coordinates and Star Glyphs that utilizes the advantages of both representations to offset the disadvantages they have separately. We discuss the role of uniform and stepped colour scales in the visual comparison of non-adjacent items and Star Glyphs. parallel Glyphs provide capabilities for focus-in-context exploration using two types of lenses and interactions specific to the 3D space.
We present a new parallel multiresolution volume rendering algorithm for visualizing largedata sets. Using the wavelet transform, the raw data is first converted to a multi resolution wavelet tree. To eliminate the d...
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We present a new parallel multiresolution volume rendering algorithm for visualizing largedata sets. Using the wavelet transform, the raw data is first converted to a multi resolution wavelet tree. To eliminate the data dependency between processors at run-time, and achieve load-balanced rendering, we design a novel algorithm to partition the tree and distribute the data along a hierarchical space-filling curve with error-guided bucketization. Further optimization is achieved by storing reconstructed data at pre-selected tree nodes for each processor based on the available storage resources to reduce the overall wavelet reconstruction cost. At run time, the wavelet tree is first traversed according to the user-specified error tolerance. data blocks of different resolutions that satisfy the error tolerance are then decompressed and rendered to compose the final image in parallel. Experimental results showed that our algorithm can reduce the run-time communication cost to a minimum and ensure a well-balanced workload among processors when visualizing gigabytes of data with arbitrary error tolerances. (c) 2005 Elsevier B.V.. All rights reserved.
This paper presents two parallel I/O methods for the visualization of time-varying volume data in a high-performance computing environment. We discuss the interplay between the parallel renderer, I/O strategy, and fil...
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This paper presents two parallel I/O methods for the visualization of time-varying volume data in a high-performance computing environment. We discuss the interplay between the parallel renderer, I/O strategy, and file system, and show the results of our study on the performance of the I/O strategies with and without MPI parallel I/O support. The targeted application is earthquake modeling using a large 3D unstructured mesh consisting of one hundred millions cells. Our test results on the HP/Cornpaq AlphaServer operated at the Pittsburgh Supercomputing Center demonstrate that the I/O methods effectively remove the I/O bottlenecks commonly present in time-varying datavisualization, and therefore help significantly lower interfrarne delay. This high-performance visualization solution allows scientists to explore their data in the temporal, spatial, and visualization domains at high resolution. Such new explorability, likely not presently available to most computational science groups, will help lead to many new insights into the modeled physical and chemical processes. (c) 2005 Elsevier B.V. All rights reserved.
We describe a system for the texture-based direct volume visualization of largedata sets on a PC cluster equipped with GPUs. The data is partitioned into volume bricks in object space, and the intermediate images are...
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We describe a system for the texture-based direct volume visualization of largedata sets on a PC cluster equipped with GPUs. The data is partitioned into volume bricks in object space, and the intermediate images are combined to a final picture in a sort-last approach. Hierarchical wavelet compression is applied to increase the effective size of volumes that can be handled. An adaptive rendering mechanism takes into account the viewing parameters and the properties of the data set to adjust the texture resolution and number of slices. We discuss the specific issues of this adaptive and hierarchical approach in the context of a distributed memory architecture and present corresponding solutions. Furthermore, our compositing scheme takes into account the footprints of volume bricks to minimize the costs for reading from framebuffer, network communication, and blending. A detailed performance analysis is provided for several network, CPU, and GPU architectures-and scaling characteristics of the parallel system are discussed. For example, our tests on a eight-node AMD64 cluster with InfiniBand show a rendering speed of 6 frames per second for a 2048 x 1024 x 1878 data set on a 1024(2) viewport. (c) 2005 Elsevier B.V. All rights reserved.
We present a new parallel multiresolution volume rendering framework for large-scale time-varying datavisualization using the wavelet-based time-space partitioning (WTSP) tree. Utilizing the wavelet transform, a larg...
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Graph drawing is a basic visualization tool that works well for graphs having up to hundreds of nodes and edges. At greater scale, data density and occlusion problems often negate its effectiveness. Conventional pan-a...
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ISBN:
(纸本)0780387793
Graph drawing is a basic visualization tool that works well for graphs having up to hundreds of nodes and edges. At greater scale, data density and occlusion problems often negate its effectiveness. Conventional pan-and-zoom, multiscale, and geometric fisheye views are not fully satisfactory solutions to this problem. As an alternative, we propose a topological zooming method. It precomputes a hierarchy of coarsened graphs that are combined on-the-fly into renderings, with the level of detail dependent on distance from one or more foci. A related geometric distortion method yields constant information density displays from these renderings.
Time series are an important type of data with applications in virtually every aspect of the real world. Often a large number of time series have to be monitored and analyzed in parallel. Sets of time series may show ...
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ISBN:
(纸本)078039464X
Time series are an important type of data with applications in virtually every aspect of the real world. Often a large number of time series have to be monitored and analyzed in parallel. Sets of time series may show intrinsic hierarchical relationships and varying degrees of importance among the individual time series. Effective techniques for visually analyzing large sets of time series should encode the relative importance and hierarchical ordering of the time series data by size and position, and should also provide a high degree of regularity ill order to support comparability by the analyst. In this paper, we present a framework for visualizing large sets of time series. Based on the notion of inter time series importance relationships, we define a set of objective functions that space-filling layout schemes for time series data should obey. We develop an efficient algorithm addressing the identified problems by generating layouts that reflect hierarchy- and importance-based relationships in a regular layout with favorable aspect ratios. We apply our technique to a number of real-world data sets including sales and stock data, and we compare our technique with an aspect ratio aware variant of the well-known TreeMap algorithm. The examples show the advantages and practical usefulness of our layout algorithm.
In order to gain insight into multivariate data, complex structures must be analysed and understood. parallel coordinates is an excellent tool for visualizing this type of data but has its limitations. This paper deal...
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ISBN:
(纸本)078039464X
In order to gain insight into multivariate data, complex structures must be analysed and understood. parallel coordinates is an excellent tool for visualizing this type of data but has its limitations. This paper deals with one of its main limitations - how to visualize a large number of data items without hiding the inherent structure they constitute. We solve this problem by constructing clusters and using high-precision textures to represent them. We also use transfer functions that operate on the high-precision textures in order to highlight different aspects of the cluster characteristics. Providing pre-defined transfer functions as well as the support to draw customized transfer functions makes it possible to extract different aspects of the data. We also show how feature animation can be used as guidance when simultaneously analysing several clusters. This technique makes it possible to visually represent statistical information about clusters and thus guides the user, making the analysis process more efficient.
We present a new parallel multiresolution volume rendering algorithm for visualizing largedata sets. Using the wavelet transform, the raw data is first converted to a multi resolution wavelet tree. To eliminate the d...
详细信息
We present a new parallel multiresolution volume rendering algorithm for visualizing largedata sets. Using the wavelet transform, the raw data is first converted to a multi resolution wavelet tree. To eliminate the data dependency between processors at run-time, and achieve load-balanced rendering, we design a novel algorithm to partition the tree and distribute the data along a hierarchical space-filling curve with error-guided bucketization. Further optimization is achieved by storing reconstructed data at pre-selected tree nodes for each processor based on the available storage resources to reduce the overall wavelet reconstruction cost. At run time, the wavelet tree is first traversed according to the user-specified error tolerance. data blocks of different resolutions that satisfy the error tolerance are then decompressed and rendered to compose the final image in parallel. Experimental results showed that our algorithm can reduce the run-time communication cost to a minimum and ensure a well-balanced workload among processors when visualizing gigabytes of data with arbitrary error tolerances. (c) 2005 Elsevier B.V.. All rights reserved.
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