• Computational Grid Applications (Thursday 10:30AM-Noon)
    Room A102/104/106
    Chair: Ann Chervenak, Georgia Tech

    • Title: Applying Scheduling and Tuning to On-line Parallel Tomography
    • Authors:
      Shava Smallen (University of California, San Diego)
      Henri Casanova (University of California, San Diego)
      Francine Berman (University of California, San Diego)
      Best Student Paper Finalist
    • Abstract:
      Tomography is a popular technique to reconstruct the three-dimensional structure of an object from a series of two-dimensional projections. Tomography is resource-intensive and deployment of a parallel implementation onto Computational Grid platforms has been studied in previous work. In this work, we address on-line execution of the application where computation is performed as data is collected from an on-line instrument. The goal is to compute incremental 3-D reconstructions that provide quasi-real-time feedback to the user.

      We model on-line parallel tomography as a tunable application: trade-offs between resolution of the reconstruction and frequency of feedback can be used to accommodate various resource availabilities. We demonstrate that application scheduling/tuning can be framed as multiple constrained optimization problems and evaluate our methodology in simulation. Our results show that prediction of dynamic network performance is key to efficient scheduling and that tunability allows for production runs of on-line parallel tomography in Computational Grid environments.

    • Title: An Automatic Design Optimization Tool and its Application to Computational Fluid Dynamics
    • Authors:
      David Abramson (Monash University)
      Andrew Lewis (Griffith University)
      Tom Peachey (Monash University)
      Clive Fletcher (University of New South Wales)
    • Abstract:
      In this paper we describe the Nimrod/O design optimization tool, and its application in computational fluid dynamics. Nimrod/O facilitates the use of an arbitrary computational model to drive an automatic optimization process. This means that the user can parameterise an arbitrary problem, and then ask the tool to compute the parameter values that minimize or maximise a design objective function. The paper describes the Nimrod/O system, and then discusses a case study in the evaluation of an aerofoil problem. The problem involves computing the shape and angle of attack of the aerofoil that maximises the lift to drag ratio. The results show that our general approach is extremely flexible and delivers better results than a program that was developed specifically for the problem. Moreover, it only took us a few hours to set up the tool for the new problem and required no software development.

    • Title: Numerical Libraries And The Grid: The GrADS Experiments With ScaLAPACK
    • Authors:
      Antoine Petitet (Sun France Benchmark Center)
      Susan Blackford (University of Tennessee)
      Jack Dongarra (University of Tennessee)
      Brett Ellis (University of Tennessee)
      Graham Fagg (University of Tennessee)
      Kenneth Roche (University of Tennessee)
      Sathish Vadhiyar (University of Tennessee)
    • Abstract:
      This paper describes an overall framework for the design of numerical libraries on a computational Grid of processors where the processors may be geographically distributed and under the control of a Grid-based scheduling system. A set of experiments are presented in the context of solving systems of linear equations using routines from the ScaLAPACK software collection along with various grid service components, such as Globus, NWS, and Autopilot.