This algorithmic "tool" is general and has been used in several tasks, such as: online/adaptive parameter estimation, online classification, adaptive distributed learning, just to name a few. The algorithm can be used in both linear and non-linear scenarios (using kernels).
^Yamada, I.; Ogura, N. (2003). "Adaptive projected subgradient method and its applications to set theoretic adaptive filtering". The Thirty-seventh Asilomar Conference on Signals, Systems & Computers, 2003. p. 600. doi:10.1109/ACSSC.2003.1291982. ISBN0-7803-8104-1.
^Yamada, I.; Ogura, N. (2005). "Adaptive Projected Subgradient Method for Asymptotic Minimization of Sequence of Nonnegative Convex Functions". Numerical Functional Analysis and Optimization25 (7–8): 593. doi:10.1081/NFA-200045806.