Hao Xiumei was born in 1964. She received the master's degree from Liaocheng University in 1987. She is now a doctoral student in School of Mathematics and System Science, Shandong University. Her current research interests are rough system theory and its application. E-mail: hxm0912@126.com Fu Haiyan was born in 1978. She received the master's degree from Shandong University in 2002. She is now a doctoral student in School of Mathematics and System Science, Shandong University. Her current research interests are rough system theory and its application. E-mail: yanzi78@163.com Shi Kaiquan was born in 1945. He is now a Ph.D. tutor in School of Mathematics and System Science, and School of Control Science and Engineering, Shandong University. In 2002, he presented S-rough sets (singular rough sets), and then put forward function S-rough sets (function Singular rough sets) in 2005, both of which possess very important theoretical and practical significance. Now his research interests include the theory and applications of rough sets and fuzzy sets. E-mail: shikq@sdu.edu.cn