Under CopyrightOtt, JonathanJonathanOttHild, JuttaJuttaHildBauer, AlexanderAlexanderBauer2022-03-1112.2.20102009https://publica.fraunhofer.de/handle/publica/36274510.24406/publica-fhg-362745Coping with threats such as terrorism, crime, natural hazards or industrial accidents requires early detection and correct assessment of critical situations, followed by appropriate actions to avoid potential damage to person or property. We here focus on threat prevention in closed properties of traffic infrastructures (railway stations, harbours, airports) or logistics centres. To early detect and prevent damage, the property is continuously monitored by sensors and security staff. We propose to model the threat situation of the property as a continuous-time Markov decision process (CMDP). The CMDP-model is used as core of a decision support system (DSS), which assists the security staff in two aspects: it facilitates to identify the threat situation of the property and suggests the cost-optimal action by which the property will be kept in or returned into a safe state. The concept is also shown in a numerical example.en004670conference paper