Ms. Vaishali Amin has successfully defended her Ph.D. dissertation, “Time-Frequency Analysis Techniques for Non-Stationary Signals Using Sparsity,” on April 5, 2022. The dissertation defense was delivered virtually through Zoom.

Vaishali’s dissertation develops several time-frequency analysis techniques that enable improved instantaneous frequency estimation of non-stationary signals with high resolution, mitigate undesired effects of cross-terms and artifacts and achieve highly concentrated robust time-frequency representations. Vaishali attacked the problems from three broad categories: iterative missing data recovery, adaptive local filtering based approach, and signal stationarization-based approaches. The dissertation also develops knowledge-based time-frequency representations based on signal stationarization and applies them for the Doppler analysis of over-the-horizon radar (OTHR) signals.

Vaishali’s Ph.D. studies were partially supported by the Air Force Research Laboratory.