You can find some past keynote recordings in YouTube. The first one requires a direct link, the others are publicly available at IEEE NorCAS YouTube channel.
Direct links to the videos:
An-Yeu (Andy) Wu: Compressive sensing (CS) Circuits and Systems for Intelligent Biomedical Signal Processing
Alberto Bosio: Approximate Computing: Test and Reliability issues and opportunities
Tim Constandinou: Future Human: Merging Minds and Machines
Alexander Wyglinsky: Software-Defined Radio Education and the Next Generation of Wireless Communications Innovators