1. College of Marine Electrical Engineering, Dalian Maritime University, Dalian, Liaoning, China
2. Navigation College, Dalian Maritime University, Dalian, Liaoning, China
3. School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
4. Department of Computer Science, The University of Alabama, Tuscaloosa, AL, USA
5. Department of Informatics, University of Oslo, Oslo, Norway