Ling Ren is an Assistant Professor in the Department of Computer Science at the University of Illinois at Urbana-Champaign. Prior to joining the University of Illinois, he obtained his Ph.D. from MIT and worked at VMware Research. His research interests include security, cryptography, and distributed algorithms. In this talk, I will present a protocol that simultaneously supports dynamic participation and achieves constant latency. The core technique is to extend the classic BFT approach from static quorum size to dynamic quorum size, i.e., according to the current participation level, while preserving important properties of static quorums. Joint work with Atsuki Momose.