College of Automation & Electronic Engineering, Qingdao University of Science & Technology, Qingdao 266042, China;
School of Mathematics & Physics, Qingdao University of Science & Technology, Qingdao 266061, China;
College of Automation & Electronic Engineering, Qingdao University of Science & Technology, Qingdao 266042, China;
School of Mathematics & Physics, Qingdao University of Science & Technology, Qingdao 266061, China;