Real-time Monitoring and Early Warning Analysis of Urban Railway Operation Based on Multi-parameter Vital Signs of Subway Drivers in Plateau Environment

In order to ensure the personal safety of the drivers and passengers of rail transit in plateau environment, the vital signs and train conditions of the drivers and passengers are taken as the research object, and the dynamic relationship between them is studied and analyzed. In this paper, subway drivers under normal operation conditions are taken as research objects to establish the vital signs monitoring and early warning system. The vital signs data of the subway drivers, such as heart rate (HR), respiratory rate (RR), body temperature (T) and blood oxygen saturation (SPO2) of the subway driver are collected by the head-mounted sensor, and the least mean square adaptive filtering algorithm is used to preprocess the data and eliminate the interference information. Based on the improved BP (Back Propagation) neural network algorithm, a prediction model is established to predict the vital signs of subway drivers in real-time. We use the early warning score evaluation method to measure the risk of subway drivers' vital signs, and then the necessary judgment basis can be provided to dispatchers in the control center. Experiments show that the system developed in this paper can accurately predict the evolution of subway drivers' vital signs, and timely warn the abnormal states. The predicted value of vital signs is consistent with the actual value, and the absolute error of prediction is less than 0.5 which is within the allowable range

Advances in Microwave Near-Field Imaging: Prototypes, Systems, and Applications

A near-field microwave imaging system attempts to reveal the presence of an object and/or an electrical property distribution by measuring the scattered field from many positions surrounding the object. Over the past few decades, both the hardware and software components of a near-field microwave imaging system technology have attracted interest throughout the world. Due to limitations of hardware technology (unavailability of data acquisition apparatus), experimental microwave imaging is very challenging for the pioneers. However, Probably due to the hardware cost, most of the studies (operating at a few GHz) were still focused on software only. The feasibility of using microwave approaches to image different types of objects have been tested and verified by simulations in a variety of applications. Further, work has been conducted on improving both quantitative and qualitative algorithms to improve simulated reconstruction results. Nowadays, benefitting from the hardware progress and reduction of their cost, researchers are eager to pursue real experimental validations instead of simulations, and, more unique prototypes and commercial systems have been built for various applications. These prototypes and systems are a result of years of dedicated work and it is important to review the advancements in developed prototype systems. The article will provide an overview of the many of the systems designed from different research groups throughout the world, for applications of near-field microwave imaging. The article further outlines challenges faced in current microwave near-field imaging, developmental tendencies of engineers and scientists, and the future outlook