1. School of Computer and Electrical Engineering, Hunan University of Arts and Science, Changde, Hunan 410205, P. R. China
2. Hunan Provincial Key Laboratory of Finance & Economics Big Data Science and Technology, School of information technology and management, Hunan University of Finance and Economics, Changsha, Hunan 410205, P. R. China
3. School of Geophysics and Measurement-control Technology, East China University of Technology, Nanchang, Jiangxi 330013, P. R. China