Visible to the public Biblio

Filters: Keyword is game theory  [Clear All Filters]
2019-05-30
Saqib Hasan, Amin Ghafouri, Abhishek Dubey, Gabor Karsai, Xenofon Koutsoukos.  2018.  Vulnerability analysis of power systems based on cyber-attack and defense models. 2018 IEEE Power Energy Society Innovative Smart Grid Technologies Conference (ISGT). :1-5.

Reliable operation of power systems is a primary challenge for the system operators. With the advancement in technology and grid automation, power systems are becoming more vulnerable to cyber-attacks. The main goal of adversaries is to take advantage of these vulnerabilities and destabilize the system. This paper describes a game-theoretic approach to attacker / defender modeling in power systems. In our models, the attacker can strategically identify the subset of substations that maximize damage when compromised. However, the defender can identify the critical subset of substations to protect in order to minimize the damage when an attacker launches a cyber-attack. The algorithms for these models are applied to the standard IEEE-14, 39, and 57 bus examples to identify the critical set of substations given an attacker and a defender budget.

2019-05-29
Amin Ghafouri, Xenofon Koutsoukos, Yevgeniy Vorobeychik, Waseem Abbas, Aron Laszka.  2019.  A game-theoretic approach for selecting optimal time-dependent thresholds for anomaly detection. International Foundation for Autonomous Agents and Multi-Agent Systems Journal. 33

Adversaries may cause significant damage to smart infrastructure using malicious attacks. To detect and mitigate these attacks before they can cause physical damage, operators can deploy anomaly detection systems (ADS), which can alarm operators to suspicious activities. However, detection thresholds of ADS need to be configured properly, as an oversensitive detector raises a prohibitively large number of false alarms, while an undersensitive detector may miss actual attacks. This is an especially challenging problem in dynamical environments, where the impact of attacks may significantly vary over time. Using a game-theoretic approach, we formulate the problem of computing optimal detection thresholds which minimize both the number of false alarms and the probability of missing actual attacks as a two-player Stackelberg security game. We provide an efficient dynamic programming-based algorithm for solving the game, thereby finding optimal detection thresholds. We analyze the performance of the proposed algorithm and show that its running time scales polynomially as the length of the time horizon of interest increases. In addition, we study the problem of finding optimal thresholds in the presence of both random faults and attacks. Finally, we evaluate our result using a case study of contamination attacks in water networks, and show that our optimal thresholds significantly outperform fixed thresholds that do not consider that the environment is dynamical.