This work is also closely related with multi-task learning, which aims to jointly learn multiple related tasks with the benefit of using interactive features under a share representation (Ben-David and Schuller, 2003;Ando and Zhang, 2005;Parameswaran and Weinberger, 2010).
as far as we know, multi-task learning usually assumes the existence of data with labels for multiple tasks at the same time, which is unavailable in our scenario, making our problem more particularly difficult.