Interactive Pollution Simulation

1
Interactive Air Pollution Simulation in
int.eu.grid
Branislav imo1, Viera ípkova1, Martin Gaák2,
Ladislav Hluchý1 1) Institute of Informatics,
Slovak Academy of Sciences 2) MicroStep-MIS Contac
t branislav.simo_at_savba.sk

• Interactivity in general
• A data channel is created between the
  application running in the grid and a special
  application specific plug-in running inside the
  Migrating Desktop.
• The channel passes all the data from the standard
  output of the application to the plug-in and data
  sent to the channel are passed to the standard
  input of the application.
• MPI The channel takes output from all jobs MPI
  processes input is connected to the master
  process only.
• To avoid firewall problems, the interactive
  channel data is forwarded via an intermediate
  server Roaming Access Server.

• IMS Model Suite
• Environmental Dispersion Modeling using
  Lagrangian Trajectory Model.
• Complex commercial software system for prediction
  of the consequences of environmental pollution,
  nuclear accident or other emergence.
• Numerical modeling of phenomena
• Continuous or short-term releases of multiple
  simultaneous pollutant species
• Dispersion of multiple pollutants
• Atmospheric transport and diffusion under
  changing weather conditions
• Deposition (wet, dry)
• Radioactive decay
• Pre-defined scenarios
• Initially a sequential model running on Windows
  OS.
• Computational time increases with raising number
  of simulated particles. Individual particles are
  independent of each other.

The implementation

• Interactive steering of a simulation running on
  the grid
• The Migrating Desktop UI is used as a platform
  for submitting the application to the grid and
  launching the application specific interaction
  plug-in.
• User can submit the application using the
  predefined parameters stored as an icon on the
  desktop. One of the parameters specifies the use
  of interactive channel.
• When the job enters running state the user starts
  the application plug-in, which connects via
  interactive channel to the application.
• As the computation proceeds, images showing map
  with the particles are sent to the user for each
  hour of simulation time (i.e. every few seconds).
  Images are buffered locally to enable viewing
  past images and for playing simple animation.
• Each simulation step, the user can send a command
  to split particles, thus doubling particle count
  simulated. There is also a command for
  terminating the simulation correctly instead of
  aborting it the usual way.
• Textual debugging and informative messages
  generated by the application are also transferred
  via the interactive channel.
• Interactive application allows users to view the
  development of the simulation in real-time,
  influence the simulation interactively and see
  the immediate results of their actions.

• Gridification and interactivity
• Reimplementation of some of the functionality of
  Borland C Builder libraries to make it compile
  on Linux.
• Creation of wrapper scripts for set-up of
  application environment.
• MPI parallelization. Particles are divided among
  MPI processes.
• Modification for interactive channel Images and
  messages multiplexed into stdout stdin is
  monitored for commands from user.
• Implementation of application plug-in for
  Migrating Desktop that is used for communication
  with application.

• Int.eu.grid tools used
• gLogin
• Creates interactive channel between grid node(s)
  and users machine
• Based on SSH with GSI
• Migrating Desktop
• Java client GUI wrapping various grid tools
  (security, data management, job management).
  Supports plug-ins (OSGI architecture, like
  Eclipse)
• Application specific plug-in can be created to
  handle the data flowing to/from the interactive
  channel

Project reference int.eu.grid - EU 6FP
Interactive European Grid project, 2006-2008,
contract no. 031857 Web www.interactive-grid.eu