“…MTL is widely used in a broad range of practical applications, including face detection (Ranjan et al, 2017;Ahn et al, 2018;Chen et al, 2018;Zhao et al, 2019), federated MTL (Smith et al, 2017;Corinzia and Buhmann, 2019;Sattler et al, 2019), speech recognition (Huang et al, 2013;Kim et al, 2017;Liu et al, 2017;Subramanian et al, 2018), and other applications (Doersch and Zisserman, 2017;Han et al, 2017;Liu et al, 2017Liu et al, , 2019Hessel et al, 2019). Ranjan et al (2017) presented an algorithm for simultaneous face detection, landmark localization, pose estimation, and gender recognition.…”