Euro-Par 2007 Workshops: Parallel Processing : HPPC 2007, UNICORE Summit 2007, and VHPC 2007, Rennes, France, August 28-31, 2007, Revised Selected Papers - Luc Bougé, Martti Forsell, Jesper Larsson Träff, Achim Streit, Wolfgang Ziegler, Michael Alexander, Stephen Childs ((Lecture Notes in Computer Science))