Biblio

As the Industrial Internet of Things (IIot) becomes more prevalent in critical application domains, ensuring security and resilience in the face of cyber-attacks is becoming an issue of paramount importance. Cyber-attacks against critical infrastructures, for example, against smart water-distribution and transportation systems, pose serious threats to public health and safety. Owing to the severity of these threats, a variety of security techniques are available. However, no single technique can address the whole spectrum of cyber-attacks that may be launched by a determined and resourceful attacker. In light of this, we consider a multi-pronged approach for designing secure and resilient IIoT systems, which integrates redundancy, diversity, and hardening techniques. We introduce a framework for quantifying cyber-security risks and optimizing IIoT design by determining security investments in redundancy, diversity, and hardening. To demonstrate the applicability of our framework, we present a case study in water-distribution systems. Our numerical evaluation shows that integrating redundancy, diversity, and hardening can lead to reduced security risk at the same cost.

Network connectivity is a primary attribute and a characteristic phenomenon of any networked system. A high connectivity is often desired within networks; for instance to increase robustness to failures, and resilience against attacks. A typical approach to increasing network connectivity is to strategically add links; however adding links is not always the most suitable option. In this paper, we propose an alternative approach to improving network connectivity, that is by making a small subset of nodes and edges “trusted,” which means that such nodes and edges remain intact at all times and are insusceptible to failures. We then show that by controlling the number of trusted nodes and edges, any desired level of network connectivity can be obtained. Along with characterizing network connectivity with trusted nodes and edges, we present heuristics to compute a small number of such nodes and edges. Finally, we illustrate our results on various networks.

We investigate the coverage efficiency of a sensor network consisting of sensors with circular sensing footprints of different radii. The objective is to completely cover a region in an efficient manner through a controlled (or deterministic) deployment of such sensors. In particular, it is shown that when sensing nodes of two different radii are used for complete coverage, the coverage density is increased, and the sensing cost is significantly reduced as compared to the homogeneous case, in which all nodes have the same sensing radius. Configurations of heterogeneous disks of multiple radii to achieve efficient circle coverings are presented and analyzed.