We study differentially private stochastic convex optimization (DP-SCO) under user-level privacy, where each user may hold multiple data items. Existing work for user-level DP-SCO either requires super-polynomial runtime or requires a number of users that grows polynomially with the dimensionality of the problem. We develop new algorithms for user-level DP-SCO that obtain optimal rates,…

Tracking biosignals is crucial for monitoring wellness and preempting the development of severe medical conditions. Today, wearable devices can conveniently record various biosignals, creating the opportunity to monitor health status without disruption to one's daily routine. Despite the widespread use of wearable devices and existing digital biomarkers, the absence of curated data with annotated medical…