v1 - group rehearsal version 18/06/2014
v2 - draft for HF PWG discussion 20/06/2014
v3 -  Zhenyu's comments addressed
v4 - Yifei's, Zhenyu's, Daniel's and Barbara's comments addressed, 23/06/2014
v5 - draft for Collaboration discussion 24/06/2014
v6 - Gang's comments addressed, 29/06/2014