Underground Communications

OR ◽  
1953 ◽  
Vol 4 (4) ◽  
pp. 61
Fire Safety ◽  
2018 ◽  
pp. 101-106
Author(s):  
D. Smolyak ◽  
Yu. Baran

Introduction. The main task of the SNSS rescue units is to provide emergency assistance and rescue of the population in case of occurrence of events that threaten their life and health or may cause material damage. The success of rescuing people by fire brigades depends on several factors. First of all, it is the presence of special fire fighting equipment for rescue operations at the altitude and the technical possibility of its use. Today, the rescue of the victim from a sewage well, a water collector - a phenomenon is still quite widespread. Such cases come from the fault of the victim, yes, and due to negligence of the relevant utilities. Purpose. In rescuing people from multistory buildings, rescuers use motorbikes, but if the motorway can not arrive at an emergency, and manual fire ladders do not reach the required height, fire and rescue units use fire ropes and evacuate people with them.Rescue works in wells of underground communications are divided into the following stages: • Preparation of the necessary equipment and place of the event for the execution of works; • Emergency rescue directly into the well; • Preparation of the victim for lifting to the surface and transportation; • lifesaving on the surface. Methods. For descent from the floors or lifting from the underground well, the survivors of the survivors knit a double rescue loop from the fire rope and put it on the victim. But there is a better alternative to the double rescue loop - this is a rescue triangle. Results. Characteristics of the rescue triangle: time of dressing, comfort of dressing, durability, care of the rescue triangle.Conclusion. Equipping at least fire trucks equipped with rescue tripods, rescue triangles will greatly simplify the work and increase the efficiency of rescue works from the floors of the house or underground collectors (wells).


2019 ◽  
Vol 8 (3) ◽  
pp. 41 ◽  
Author(s):  
Abdul Salam

In underground (UG) multiple-input and multiple-output (MIMO), transmit beamforming is used to focus energy in the desired direction. There are three different paths in the underground soil medium through which the waves propagate to reach the receiver. When the UG receiver receives a desired data stream only from the desired path, then the UG MIMO channel becomes a three-path (lateral, direct, and reflected) interference channel. Accordingly, the capacity region of the UG MIMO three-path interference channel, and the degrees of freedom (multiplexing gain of this MIMO channel) requires careful modeling. Therefore, expressions are required for the degrees of freedom of the UG MIMO interference channel. The underground receiver needs to perfectly cancel the interference from the three different components of the EM waves propagating in the soil medium. This concept is based upon reducing the interference of the undesired components to a minimum level at the UG receiver using the receive beamforming. In this paper, underground environment-aware MIMO using transmit and receive beamforming has been developed. The optimal transmit and receive beamforming, combining vectors under minimal intercomponent interference constraints, are derived. It is shown that UG MIMO performs best when all three components of the wireless UG channel are leveraged for beamforming. The environment-aware UG MIMO technique leads to three-fold performance improvements and paves the way for design and development of next-generation sensor-guided irrigation systems in the field of digital agriculture. Based on the analysis of underground radio-wave propagation in subsurface radio channels, a phased-array antenna design is presented that uses water content information and beam-steering mechanisms to improve efficiency and communication range of wireless underground communications. It is shown that the subsurface beamforming using phased-array antennas improves wireless underground communications by using the array element optimization and soil–air interface refraction adjustment schemes. This design is useful for subsurface communication system where sophisticated sensors and software systems are used as data collection tools that measure, record, and manage spatial and temporal data in the field of digital agriculture.


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