QI Jun-Jun Master student at Shandong University. He received his bachelor degree from Nanjing Normal University in 2005, His research interest covers stochastic control theory. E-mail: qi_junjun@yahoo.com.cn ZHANG Wei-Hai Professor at Shandong University of Science and Technology. He received his Ph.D. degree from Zhejiang University in 1998. His research interest covers linear and nonlinear stochastic optimal control, robust H∞ control, and stochastic stability. Corresponding author of this paper. E-mail: w_hzhang@163.com