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ABSTRACT Modelling safety of critical infrastructure free of outside impacts is presented. New safety indicators for a critical infrastructure are defined and procedures of their determination in the case of created model are proposed. Next, as its exemplary application, the safety of the port oil terminal critical infrastructure free of any outside impacts is examined. On the basis of this critical infrastructure safety statistical data coming from the operators, its safety is modelled, identified and predicted.
INTRODUCTION We define critical infrastructure as a complex system in its operating environment that significant features are inside-system dependencies and outside-system dependencies (Lague et al., 2015). The safety indicators for such system, which are crucial for its operators, can be obtained by using of an original and innovative probabilistic approach to modelling of operation threats and extreme weather hazards impact on its safety (Kołowrocki and Soszyńska-Budny, 2017). In the first step of the proposed approach, starting from a simplest pure safety model without considering outside impacts, we can define the critical infrastructure and its assets practically useful safety indicators (SafI1-SafI8). In the next steps of the proposed approach, the simplest safety model presented in this paper can be joined with the critical infrastructure operation process model, and the climate-weather change model. Together with these two models, one can create safety models of critical infrastructure respectively related to the operating environment impacts, the climate-weather impacts and the operation and climate-weather joint impacts (Kołowrocki and Soszyńska-Budny, 2017, 2019).
MULTI-STATE APPROACH TO CRITICAL INFRASTRUCTURE SAFETY In the multistate safety analysis to define the critical infrastructure with degrading/ageing components/assets, we assume that (Kołowrocki and Soszyńska-Budny, 2011; Kołowrocki 2014):–n is the number of the critical infrastructure assets,
–Ai, i = 1,2,…,n, are the critical infrastructure assets,
–all assets and the critical infrastructure have the safety state set {0,1,…,z}, z ≥ 1,
the safety states are ordered, the safety state 0 is the worst and the safety state z is the best,
–r, r ? {1,2,…, z}, is the critical safety state (critical infrastructure and its assets staying in the safety states less than the critical state is highly dangerous for them and for their operating environment),
–Ti(u), i = 1,2,…,n, are independent random variables representing the lifetimes of assets Ai), i = 1,2,…,n, in the safety state subset {u,u+1,…,z}, u = 1,2,…,z, while they were in the safety state z at the moment t = 0,
–T(u) is a variable representing the lifetime of the critical infrastructure in the safety state subset {u,u+1,…,z}, u = 1,2,…,z, while it was in the safety state z at the moment t = 0,
–the assets and the critical infrastructure safety states degrade with time t (measured in years),
–si(t) is the asset Ai safety state at the moment t, t ≥ 0, given that it was in the safety state z at the moment t = 0.
–s(t) is the critical infrastructure safety state at the moment t, t ≥ 0, while it was in the safety state z at the moment t = 0.
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