## 2 Related Work
They used IoT technology to track the location of the fire and the location of the occupants and then direct them towards a safe exit. Their implementation used Bluetooth Low Energy (BLE) beacons, and they used occupants' mobile phones to track their location. They also used smoke and temperature sensors to track areas, and in the case of fire, the system used multiple networks, including WiFi and the Digimesh, to increase its resilience. The messages can be published or subscribed to through an MQTT broker, and the occupants can use an installed map that updates automatically on their mobile phones. This map provides the occupant's information about the dander levels to be avoided. Moreover, they have installed exit signs inside the building, which dynamically changes their status to guide people to the exit. Our implementation is for usage inside ships, and therefore passengers will change in every new voyage. Moreover, it is not legal to install a live-updated ship's map on passenger mobile phones. For these reasons, an automatic updating map of the MVZs has been installed on the IoT platform and is visible through the IoT dashboard. The control of the IoT dashboard takes place through a specially trained crew, and there are also sensors installed on the ship that can automatically update the dangerous zones or decks on the map. Dangerous MVZs are automatically avoided as the digital signage lights change their status, and occupants can follow the safest way to the muster station through digital signage. To accomplish a real-time evacuation system in case of a fire or other emergency, [PERSON] et al. [14] proposed a real-time fire evacuation system. As long as buildings are tall and complex, there is a need to establish clear evacuation routes, so they used Wireless Sensors Networks (WSN) and Radio Frequency Identification (RFID) in their real-time evacuation system to achieve it. In an emergency, a digital signage system helps people by indicating the best evacuation route. They also monitor the environmental conditions to provide information about the origin of a possible fire. This digital system also provides the users' pertinent information to improve the chances of survival and supplies firefighters with real-time environment information to assure better efficiency in their operations. To accomplish the wireless transmission of the sensors in their wireless network, they used Zigbee wireless transmission technology along with RFID detection points. This implementation cannot cover large buildings or ships because Zigbee and RFRID technology do not cover large areas. Moreover, their transmission speed is lower than the transmission speed of cellular technology. According to the aforementioned literature review, we conclude that digital signage services have become a major concern in emergencies, and their effects may lead to the minimization of health hazards. Early warning systems have largely been ignored up until now, and as the demand for fast and accurate warning systems is increasing, it is crucial to monitor dangerous areas with reliable IoT implementations. We must take appropriate measures promptly and make a meticulous design of the area to be covered, including all parameters. Motivated by the need for a new digital signage system for safe ship evacuations, we have introduced a flexible, reliable, and scalable IoT-based system to monitor and warn passengers and crew about the faster and safer direction to the muster station. We focused on the parameters that determine the safe evacuation of small and large ships, which may also be suitable for evacuations of other buildings such as schools, hospitals, homes, offices, etc. The evacuation plan should always be controlled by the crew, according to ship security procedures. Our proposal focuses on a reliable open-source IoT platform, including an IoT dashboard that uses an LTE/4G cellular sensor network, detects dangerous areas, and directs occupants to the muster station via the safest way in real-time.