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.

关键基础架构系统的健壮性取决于其各个元素以及它们之间的链接的有效性和脆弱性。因此，这些元素是系统的基本构建块，必须对其进行保护以免受安全威胁。目前，通过实物保护系统（PPS）的定量模型评估其实物保护水平。但是，这些模型现在已过时，因为它们不允许集成新的动态参数。因此，本文重点介绍在PPS模型开发中贝叶斯更新方法的实现，该方法将允许PPS生命周期中获得的新信息的确切参与。贝叶斯更新在软件工具中的应用允许重新计算输入参数的各个值，从而获得有关PPS系统效率的日益现实的信息。该信息可用于修改结构，并针对安全评估输出参数的设定极限值采取保护措施。创建的用例显示了使用软件支持在水关键基础设施的选定要素上开发和评估定量PPS模型的过程的示例。