Testbeds and Research Infrastructure: Development of Networks and Communities : 7th International ICST Conference, TridentCom 2011, Shanghai, China, April 17-19, 2011, Revised Selected Papers - Thanasis Korakis, Hongbin Li, Phuoc Tran-Gia, Hong-Shik Park ((Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering))