Yan Zhang is an associate professor in the School of Computing and Information Technology, University of Western Sydney. He received his PhD degree from the University of Sydney, Australia in 1994. Yan has research interests in knowledge update, program modification and evolution, logic programming, model checking, descriptive complexity theory, and information security. Yan has published many research papers in top international conferences and journals in his areas and obtained various national competitive research grants. Currently Yan is leading a research group Intelligent Systems Laborat...