Kharchenko, V.Ponochovnyi, Y. L.Waleed AK. A.Boyarchuk, A.Brezhniev, Y.Поночовний, Юрій Леонідович2023-11-222023-11-222020https://doi.org/10.1007/978-3-030-48256-5_32https://dspace.pdau.edu.ua/handle/123456789/15416Kharchenko V., Ponochovnyi Y., Waleed AK.A., Boyarchuk A., Brezhniev I. (2020) The Availability Models of Two-Zone Physical Security System Considering Cyber Attacks. In: Zamojski W., Mazurkiewicz J., Sugier J., Walkowiak T., Kacprzyk J. (eds) Theory and Applications of Dependable Computer Systems. DepCoS-RELCOMEX 2020. Advances in Intelligent Systems and Computing, vol 1173. Springer, Cham. pp 325-333. https://doi.org/10.1007/978-3-030-48256-5_32Relevance of the paper is confirmed by the need to protect the security systems themselves, not only from physical damage, but also from ceyber attacks hy intruders. The paper explores the Markov model of the two-zone cyber-physical security system. Evaluation of the functioning of the multi zone system was carried out taking into account two degrees of degradation (operative condition - the failure state ofall zones). The state space of the model (or one fragment) has a dimension of 9 states. In the proposed model, hardware failures caused by vandal attacks on objects of the first zone and software failures due to cyber attacks on the functions ofthe second zone are considered. The simulation results illustrate different transition intervals of availability indicators of various levels of degradation to a stationary state. For different degrees of degradation, the minimum value of the availabilty function, the time interval ofthe transition of the availability function to the stationary mode, and the Value of the availability function in the stationary mode are determined. When eliminating software defects and vulnerabilities, the increase in the availability function is 0.234 for a zero level of system degradation.enCyberphysical security systemavailability indicatorsMarkov modeldegradation levelsmulti-zone architectureArticle