Before revision: Stock markets are efficient in the weak form in the sense that no significant autocorrelations can be identified in the returns. However, the microscopic mechanisms are unclear. We aim at understanding the impacts of order flows on the weak-form efficiency through computational experiments based on an empirical order-driven model  .
After revision: Social and economic systems are complex adaptive systems, in which heterogenous agents interact and evolve in a URLanized manner, and macroscopic laws emerge from microscopic properties. To understand the behaviors of complex systems, computational experiments based on an empirical order-driven model .