2013 Systems and Control Seminar

2013 Systems and Control Seminar
Date July 9, 2013 17:00〜18:00
Place Tokyo Institute of Thechnology O-okayama W9 W935

Speaker Henrik Sandberg, Professor

KTH Royal Institute of Technology

Electrical Engineering
Title "Quantifying Cyber Security for Networked Control Systems"

In this talk we consider networked control systems under false-data injection attacks. Under a previously proposed adversary modeling framework, various formulations for quantifying cyber-security of control systems are formulated as constrained optimization problems. These formulations capture trade-offs in terms of attack impact on the control performance, attack detectability, and adversarial resources. The first illustrating example concerns bad data detection in Supervisory Control and Data Acquisition (SCADA) systems for electric power networks, where the vulnerability analysis problem leads to a constrained cardinality minimization problem. This problem is NP-hard, but we nevertheless identify situations where it can be solved efficiently. In such cases, we show indeed that the problem can be cast as a generalization of the minimum cut problem involving costly nodes. We further show that it can be reformulated as a standard minimum cut problem (without costly nodes) on a modified graph of proportional size. An important consequence of this result is that our approach provides the first exact efficient algorithm for the vulnerability analysis problem under a full measurement assumption. Furthermore, our approach also provides an efficient heuristic algorithm for the general NP-hard problem. In the second illustrating example, we show how the constrained optimization problems can be used to quantify cyber security in a dynamic quadruple-tank process.