The authors present a metacomputing application of multivariate, nonhierarchical statistical clustering to geographic environmental data from the 48 conterminous United States in order to produce maps of regions of ec...
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The FALCON development environment was designed around three basic data representations: scalars, vectors, and dense matrices. Utilizing the FALCON interactive restructuring system, the environment has been enhanced t...
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The FALCON development environment was designed around three basic data representations: scalars, vectors, and dense matrices. Utilizing the FALCON interactive restructuring system, the environment has been enhanced to allow the identification of structures within sparse matrices, such as diagonal matrices or symmetric matrices, and the use of this information for improving performance of the generated code. In addition, the environment supports the modification of the representation of the data. Such modifications have been shown to provide significant performance improvements.
Often, images or datasets have to be compared to facilitate choices of visualization and simulation parameters respectively. Common comparison techniques include side-by-side viewing and juxtaposition, in order to fac...
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ISBN:
(纸本)078035897X
Often, images or datasets have to be compared to facilitate choices of visualization and simulation parameters respectively. Common comparison techniques include side-by-side viewing and juxtaposition, in order to facilitate visual verification of verisimilitude. We propose quantitative techniques which accentuate differences in images and datasets. The comparison is enabled through a collection of partial metrics which, essentially, measure the lack of correlation between the datasets or images being compared. That is, they attempt to expose and measure the extent of the inherent structures in the difference between images or datasets. Besides yielding numerical attributes, the metrics also produce images which can visually highlight differences. Our metrics are simple to compute and operate in the spatial domain. We demonstrate the effectiveness of our metrics through examples for comparing images and datasets.
Often, images or datasets have to be compared, to facilitate choices of visualization and simulation parameters respectively. Common comparison techniques include side-by-side viewing and juxtaposition, in order to fa...
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ISBN:
(纸本)9780780358973
Often, images or datasets have to be compared, to facilitate choices of visualization and simulation parameters respectively. Common comparison techniques include side-by-side viewing and juxtaposition, in order to facilitate visual verification of verisimilitude. In this paper, we propose quantitative techniques which accentuate differences in images and datasets. The comparison is enabled through a collection of partial metrics which, essentially, measure the lack of correlation between the datasets or images being compared. That is, they attempt to expose and measure the extent of the inherent structures in the difference between images or datasets. Besides yielding numerical attributes, the metrics also produce images, which can visually highlight differences. Our metrics are simple to compute and operate in the spatial domain. We demonstrate the effectiveness of our metrics through examples for comparing images and datasets.
The authors present a metacomputing application of multivariate, nonhierarchical statistical clustering to geographic environmental data from the 48 conterminous United States in order to produce maps of regions of ec...
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The authors present a metacomputing application of multivariate, nonhierarchical statistical clustering to geographic environmental data from the 48 conterminous United States in order to produce maps of regions of ecological similarity, called ecoregions. These maps represent finer scale regionalizations than do those generated by the traditional technique: an expert with a marker pen. Several variables (e.g., temperature, organic matter, rainfall etc.) thought to affect the growth of vegetation are clustered at resolutions as fine as one square kilometer (1 km2). These data can represent over 7.8 million map cells in an n-dimensional (n = 9 to 25) data space. A parallel version of the iterative statistical clustering algorithm is developed by the authors using the MPI (Message Passing Interface) message passing routines. The parallel algorithm uses a classical, self-scheduling, single-program, multiple data (SPMD) organization; performs dynamic load balancing for reasonable performance in heterogeneous metacomputing environments; and provides fault tolerance by saving intermediate results for easy restarts in case of hardware failure. The parallel algorithm was tested on various geographically distributed heterogeneous metacomputing configurations involving an IBM SP3TM, an IBM SP2TM, and two SGI Origin 2000TM ’s. The tests were performed with minimal code modification, and were made possible by GlobusTM (a metacomputing software toolkit) and the Globus-enabled version of MPI (MPICH-G). Our performance tests indicate that while the algorithm works reasonably well under the metacomputing environment for a moderate number of processors, the communication overhead can become prohibitive for large processor configurations.
Presents a detailed characterization of Java application and applet workloads in terms of reuse and sharing of Java code at the program, class and method level. In order to expose more sharing opportunities, technique...
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The nano-threads programming model was proposed to effectively integrate multiprogramming on shared-memory multiprocessors, with the exploitation of fine-grain parallelism from standard applications. A prerequisite fo...
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Autoscheduling is a parallel program compilation and execution model that combines uniquely three features: Automatic extraction of loop and functional parallelism at any level of granularity, dynamic scheduling of pa...
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ISBN:
(纸本)3540649522
Autoscheduling is a parallel program compilation and execution model that combines uniquely three features: Automatic extraction of loop and functional parallelism at any level of granularity, dynamic scheduling of parallel tasks, and dynamic program adaptability on multi-programmed shared memory multiprocessors. This paper presents a technique that enhances the performance of autoscheduling in Distributed Shared Memory (DSM) multiprocessors, targetting mainly at medium and large scale systems, where poor data locality and excessive communication impose performance bottlenecks. Our technique partitions the application Hierarchical Task Graph and maps the derived partitions to clusters of processors in the DSM architecture. Autoscheduling is then applied separately for each partition to enhance data locality and reduce communication costs. Our experimental results show that partitioning achieves remarkable performance improvements compared to a standard autoscheduling environment and a commercial parallelizing compiler.
Application development for high-performance distributed computing systems, or computational grids as they are sometimes called, requires "grid-enabled" tools that hide mundane aspects of the heterogeneous g...
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