Funding for this research was provided by:
National Natural Science Foundation of China (61671087, 61272514, 61170272, 61003287)
Fok Ying Tong Education Foundation (131067)
Open Foundation of Guizhou Provincial Key Laboratory of Public Big Data (2017BDKFJJ007)
BUPT Excellent Ph.D. Students Foundation (CX2018310)
Article History
Received: 11 January 2018
Accepted: 19 June 2018
First Online: 29 June 2018