1. School of Computer Science and Technology, Zhoukou Normal University, Zhoukou 466001, Henan, P. R. China
2. Department of Computer Science, Middlesex University, London NW4 4BT, United Kingdom
3. School of Software, Northwestern Polytechnical University, Xi’an 710072, Shaanxi, P. R. China
4. Department of Computational Sciences, The University of Faisalabad, Faisalabad 38000, Pakistan