supported by the National Natural Science Foundation of China(Nos.61174060,61174070);the Specialized Research Fund for the Doctoral Program(Nos.20120172120034,20110172110033);the Fundamental Research Funds for the Central Universities(No.2012ZM0101);the Guangdong Provincial Office of Science and Technology Research Projects(No.2011B090400507);the Dongguan Science and Technology Plan Project(No.2012108102005);the Key Laboratory of Systems and Network Control,Ministry of Education