1. College of Computer Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, China
2. School of Computer Science and Technology, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
3. Kristiania University College, Oslo, Norway
4. Nanjing University of Aeronautics and Astronautics, Nanjing, China
5. Simula Research Laboratory, Oslo, Norway