On the Design of a Safety Related Middleware DDS Application for Underground Railway Environment

In the underground transportation system, communications can be disrupted whenever a train is moving from one station to another and is regarded as a normal event. Middleware DDS (Data Distribution Service) can be an alternative solution to keep important information circulated in the network even though cuts of communications are present as it offers different levels of QoS (Quality of Service). Concrete applications like surveillance system using IP cameras can use this technology, which allows exchanging data captured from video files between train wagons and train stations when the wagons stop at the station, aiming at monitoring the traffic of passenger movements who exit or enter the train from the station. The wagons will be disconnected with the global networks when the inter-station phase occurs but can continue to exchange data between different producer/consumer embedded in the wagon. The outcome of this initial research is a successful illustration of video file exchange between IP cameras to extract passengers' information using DDS Middleware in a simulation experiment.