1. School of Computer Science and Technology, Harbin Institute of Technology, Weihai, China
2. School of Astronautics, Harbin Institute of Technology, Harbin, China
3. School of Natural and Computational Sciences, Massey University, Palmerston North, New Zealand
4. Department of Computer Science, Liverpool John Moores University, Liverpool, U.K.
5. Department of Mathematics and Computer Science, Brandon University, Brandon, Canada