Quantitative approach to physical protection systems assessment of critical infrastructure elements: Use case in the Slovak Republic

The robustness of the critical infrastructure system is determined by the validity and vulnerability of its individual elements and the links between them. For this reason, these elements are the basic building blocks of the system, which must be protected from security threats. The level of their physical protection is currently assessed through quantitative models of physical protection systems (PPS). However, these models are now obsolete because they do not allow the integration of new dynamic parameters. For this reason, the article focuses on the implementation of the Bayesian updating method in the PPS model development, which will allow the exact involvement of new information obtained during the PPS life. The application of Bayesian updating to software tools allows recalculation of individual values of input parameters and thus obtaining increasingly realistic information about the efficiency of the PPS system. This information can be used to modify the structure and adopt protection measures in relation to the set limit values of the output parameters of the security assessment. The created use case shows an example of the procedure of developing and assessing a quantitative PPS model on a selected element of water critical infrastructure using software support. (C) 2020 Elsevier B.V. All rights reserved.