Understanding Sub-Second Instabilities in a Global Cyber-Physical System

Future CPS will include large, decentralized systems of semi-autonomous sensor and actuator
components, and will need to operate safely beyond human response times. One current datarich
example is the U.S. network of electronic exchange networks which is the largest and
fastest network CPS in existence, but is already known to produce a wide variety of sub-second
instabilities that are little understood and which impact safety, efficiency and accuracy. Urgent
questions facing such CPS systems are therefore: When do extreme and hence potentially
unsafe behaviors occur in CPS, in particular in the sub-second regime beyond human
intervention times? Can they be predicted? How can they be managed or prevented?
This project addresses these questions by developing a new scalable theory of CPS dynamical
behavior, focused on this sub-second regime beyond human intervention times. The theory will
be validated and verified using rigorous mathematical analysis and real-world data. The analysis
considers CPS as decentralized networks of heterogeneous semi- autonomous machinery in
which an ecology of algorithms, sensors and network links may be operating, adapting and even
competing in response to external inputs. It will employ ideas and techniques developed in the
fields of complex systems and many-body analysis. It represents new science, not just for
applications of CPS but also for the core question of dynamical behavior of CPS complex
systems. The project’s deliverables will inform the extent to which instabilities can build up
across timescales, potentially threatening CPS system stability on a global level. The theory will
allow for networking at multiple scales, coupling across multiple temporal and spatial scales,
imperfect network communications and sensors, as well as adaptive reorganization and
reconfiguration of the system. Theoretical findings are cross-checked against available empirical
data, e.g., from the decentralized network of autonomous market exchanges with its mandated
sensor systems.
The broader impacts include helping to improve safety and security for society’s CPS systems,
from financial networks, smart energy buildings and cities, to autonomous vehicle design, both
at individual and swarm level. This project is already attracting interest from stakeholders at
state, federal and international level. Results from the 8 published papers so far, have been
presented on NPR, PBS, New York Times, NBC, CBS, CNN, & in Nature, Science, as well as in
multiple international media outlets. In addition, the PI has given invited presentations for
various federal agencies including consumer protection, financial services, as well as DoD,
Pentagon and U.N. and has received significant cross-disciplinary interest within academia.