Funding for this research was provided by:
National Natural Science Foundation of China (61702098)
the science and technology planning project of Guangdong Province (2014A 010103039,2015A010103022,2014B090901002)
the Natural science fund for colleges and universities of Jiangsu province (18KJB520049)
the industry University- Research-Cooperation Project in Jiangsu Province (BY2018124)
the Next Generation Internet Technology Innovation Project of Cernet (NGII20170515)
Article History
Received: 23 August 2019
Accepted: 31 January 2020
First Online: 20 February 2020