Humboldt-Universität zu Berlin | Wirtschaftswissenschaftliche Fakultät | High Dimensional Nonstationary Time Series | About us | News Feed | News 2015 | Dissertation: S. Chao completes PhD Dissertation: S. Chao completes PhD 02.06.2015. Shi-Kang Chao finished his PhD dissertation on "Quantile Regression in Risk Calibration" and took a visiting professorship at Purdue University (US). Congratulations!