Event date:
Dec 21 2020 11:00 am

Runtime Assurance for Cyber-Physical Systems

Usama Mehmood
A Cyber-physical system (CPS) is a computer system that interacts with the physical world to perform complex functions. Many applications of CPSs like medical devices, smart grids, and robotic swarms are safety-critical systems, but their formal analysis is difficult due to their complexity. The Simplex Architecture of Sha et. al. addresses this issue by periodically monitoring the state of the system at runtime and switching the control to a verified-safe baseline controller if safety violations are imminent. The traditional Simplex approach has two significant limitations. First, its success requires creating a provably safe baseline controller.  Second, its applicability is limited to centrally controlled systems.

This talk reviews our research in addressing these limitations of the traditional Simplex approach. We propose the Black-Box Simplex Architecture, a variant of the traditional Simplex Architecture that can guarantee the safety of the overall system in the presence of an unverified---and even incorrect---baseline controller, which we treat as a black box. Next, we introduce Distributed Simplex Architecture (DSA) which widens the scope of traditional Simplex to include multiagent systems. In DSA, each agent has a local instance of traditional Simplex such that the preservation of safety in the local instances implies safety for the entire multiagent system.

About the speaker: Usama Mehmood is a computer scientist investigating the verification of cyber-physical systems. He strives to develop practical formal methods that are both scalable and useful, which demands developing new theories, programming efficient tools, and building experimental systems. Some of the application areas he has worked on include multi-agent robotic systems and smart grids. 

Usama Mehmood received a Bachelor's degree in Electrical Engineering from LUMS in 2014, and a Master's degree in Computer Science from Stony Brook University in 2019. Currently, he is a Ph.D. candidate at the Department of Computer Science at Stony Brook University under the supervision of prof. Scott A. Smolka. He is the recipient of the Stony Brook CS Department Chair Fellowship award. He has worked at MathWorks during the summer of 2018 and Facebook during the summer of 2019.

This seminar by Dr. Usama Mehmood took place via Zoom on Monday, December 21 at 11:00 am.