Air shower simulation using {\sc geant4} and commodity parallel   computing
  We present an evaluation of a simulated cosmic ray shower, based on {\sc geant4} and {\sc top-c}, which tracks all the particles in the shower. {\sc top-c} (Task Oriented Parallel C) provides a framework for parallel algorithm development which makes tractable the problem of following each particle. This method is compared with a simulation program which employs the Hillas thinning algorithm. 
L. A. Anchordoqui, G. Cooperman, V. Grinberg, T. P. McCauley, T. Paul,   S. Reucroft, J. D. Swain and G. Alverson