First Author:   Wenjun Zhao Graduate School of Economics, Hitotsubashi University zhaowenjun517@gmail.com         Second Author: Mingjie Liu China Unicom Research Institute liumj100@chinaunicom.cn         Third Author: Emiko Usui Institute of Economic Research, Hitotsubashi University emiko.usui@r.hit-u.ac.jp         Fourth Author: Ting Yin Faculty of Economics, Toyo University yin@toyo.jp