Frontiers of High Performance Computing and Networking – ISPA 2006 Workshops: ISPA 2006 International Workshops FHPCN, XHPC, S-GRACE, GridGIS, HPC-GTP, PDCE, ParDMCom, WOMP, ISDF, and UPWN, Sorrento, Italy, December 4 -7, 2006, Proceedings (Lecture Notes in Computer Science, 4331)