Abstract: Disclosed is an unmanned aerial vehicle (UAV)-aided over-the-air computing system based on full-duplex relay and a trajectory and power optimization method thereof. The UAV-aided over-the-air computing system adopts the UAV as a full-duplex relay for data fusing and forwarding. The method of the application aims at minimizing an average mean square error of over-the-air computing, and solves an optimization problem under constraints of sensor transmitting power, information transmission rate, UAV trajectory and denoising factor. For an overall joint optimization problem, each optimization variable is determined one by one by an alternative optimization method according to the high coupling of optimization variables.

Abstract: Provided is a gas water heater. The gas water heater includes a pre-mixer, a combustor having a combustion chamber in communication with a premixing chamber, a condensate water assembly configured to receive and discharge condensate water, and an apparatus for controlling the gas water heater. The pre-mixer includes a premixing chamber and an air intake fan that is configured to supply air to the combustion chamber. The air intake fan is disposed in the premixing chamber. The method includes: acquiring an intake air pressure threshold; acquiring an air intake pressure value of the air intake fan; and controlling, in response to determining based on the air intake pressure value and the intake air pressure threshold that a water seal of the condensate water assembly is at risk of being blown away, the gas water heater to stop operation.

Abstract: Disclosed is a relay selection method for unmanned aerial vehicles in post disaster emergency scenarios in underground space, comprising the following steps: collecting a maximum rate, a minimum rate and an average rate of data transmission assisted by a D2D user through an unmanned aerial vehicle (UAV) based on a prediction range of the D2D user for the UAV, and obtaining a first uncertain preference order of the D2D user for the UAV and a second uncertain preference order of the UAV for the D2D user; obtaining a preference strategy of the D2D user for the UAV based on the first uncertain preference order and the second uncertain preference order; and exchanging and matching the UAVs matched by any two D2D users based on the many-to-one bilateral matching model, so as to obtain a stable matching result of bilateral exchange.

Abstract: Disclosed is a video personnel re-identification method based on trajectory fusion in a complex underground space; an accurate personnel trajectory prediction may be realized through the Social-GAN model; and a spatio-temporal trajectory fusion model is constructed, and personnel trajectory videos that are not affected by the occlusion are introduced into the re-identification network to solve the problem of false extraction of the apparent visual features caused by the occlusion. In addition, a trajectory fusion MARS_traj data set is constructed, and a number of time frames and space coordinate information are added to the MARS data set.

Abstract: When the heading machine tunnels, a current generated by a current excitation source enters a coal seam through a movable cutting pick to form a stray current. The stray current collected by a backflow net returns to a negative electrode of a power supply through a transition resistor. When information such as the water content of the coal seam changes, the stray current and a potential difference across the transition resistor also accordingly change, and the coal seam water content information is converted into an electric signal. When the potential difference across the transition resistor is applied to two ends of a piezoelectric ceramic, the piezoelectric ceramic extends or compresses, and the electric signal is converted into a strain signal. A sensing optical fiber converts the strain signal into an optical signal detectable by a photoelectric detector. The optical signal is analyzed to obtain the coal seam water content information.

Abstract: When the heading machine tunnels, a current generated by a current excitation source enters a coal seam through a movable cutting pick to form a stray current. The stray current collected by a backflow net returns to a negative electrode of a power supply through a transition resistor. When information such as the water content of the coal seam changes, the stray current and a potential difference across the transition resistor also accordingly change, and the coal seam water content information is converted into an electric signal. When the potential difference across the transition resistor is applied to two ends of a piezoelectric ceramic, the piezoelectric ceramic extends or compresses, and the electric signal is converted into a strain signal. A sensing optical fiber converts the strain signal into an optical signal detectable by a photoelectric detector. The optical signal is analyzed to obtain the coal seam water content information.

Abstract: The present invention discloses a multi-point supported five cylinder plunger pump, including a power end assembly, a hydraulic end assembly and a reduction gearbox assembly, the power end assembly includes a crankcase, a crosshead case and a spacer frame, the crankcase, the crosshead case and the spacer frame are connected in sequence, the hydraulic end assembly is fixed on the spacer frame, the reduction gearbox assembly is fixed on the crankcase, a crankshaft support is disposed at the bottom of the crankcase, and the crankshaft support is used to support the crankcase, a crosshead support is disposed at the bottom of the crosshead case, and the crosshead support is used to support the crosshead case, a hydraulic support is disposed at the bottom of the spacer frame, and the hydraulic support is used to support the hydraulic end assembly.

Abstract: The present invention discloses a high power five cylinder plunger pump, including a power end assembly, a hydraulic end assembly and a reduction gearbox assembly, wherein the power end assembly includes a crankcase, a crosshead case and a spacer frame which are connected in sequence, the hydraulic end assembly is fixed on the spacer frame, the reduction gearbox assembly is fixed on the crankcase, the cylinder spacing of the five cylinder plunger pump is 13-14 inches, ensuring the high power output of the five cylinder plunger pump. The high power five cylinder plunger pump can effectively solve the problems of narrow area in shale gas fracturing wellsite and the need for multiple fracturing equipment, thus reducing the use of equipment and facilitating the arrangement of the wellsite.

Abstract: The present invention discloses a five cylinder plunger pump with an integral power end structure. In the power end assembly of the five cylinder plunger pump, the crankcase and the crosshead case adopt an integral welding structure, so that the power end assembly has a higher structural strength and a better support stability to reduce vibration of the whole pump. The cylinder spacing is 13-14 inches, increasing the bearing area of the connecting rod, the crosshead and the bearing bushes, and ensuring the high power output of the five cylinder plunger pump. The high power five cylinder plunger pump can effectively solve the problems of narrow area in shale gas fracturing wellsite and the need for multiple fracturing equipment, thus reducing the use of equipment and facilitating the arrangement of the wellsite. The long stroke design of 11 inches is beneficial to realize the operation requirement of large displacement and enhance the operation efficiency.