Quantitative Estimate of Infrastructure Interdependence

The advancement in information and communication technologies and the integration with electric power grids, has made the later more pervasive, extensive, and in some cases complex in terms of design, structure, operations, and management. This complexity-induced convergence means the disruptions in one part of the system cascade to other areas, causing secondary, tertiary, and even higher-order destructive effects. Increasing complexity also means an increase in both systems' vulnerabilities and threats exposure. In most countries, various control measures are being implemented by both security engineers and regulatory bodies; aiming to intensify security requirements as well as compliance. This security objective is to ensure that critical infrastructure systems are not only protected but are also effective and resilient at all times. From the perspective of network theory, the paper proposes an infrastructure interdependence reliability metric; as a technique to assess the functional and structural impact of a systematic cyberattack on system (critical infrastructure) and its interdependent systems. The metric computes the infrastructure interdependence effectiveness index and resilience ratio among interdependent infrastructure systems. The reliability approach provides a perspective in understanding how systems convergence impact systems’ overall functionality, performance, and resilience. For researchers, the study presents a new approach that advances existing discussion on systems convergence in a heterogeneous environment such as IoT.