1. Department of Computer Science, Xiamen University, China
2. ITOP Section, DNB Bank ASA, Solheimsgaten, Bergen, Norway
3. Universidad Politécnica de Madrid (UPM) Campus Montegancedo s/n, Boadilla del Monte, Madrid, Spain
4. Insitute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, China
5. School of Computer Science and Technology, Tianjin University, Tianjin, China