Multi-AUV Cooperative Target Hunting based on Improved Potential Field in a Surface-Water Environment

In this paper, target hunting aims to detect target and surround the detected target in a surface-water using Multiple Autonomous Underwater Vehicles (multi-AUV) in a given area. The main challenge in multi-AUV target hunting is the design of AUV\u27s motion path and coordination mechanism. To conduct the cooperative target hunting by multi-AUV in a surface-water environment, an integrated algorithm based on improved potential field (IPF) is proposed. First, a potential field function is established according to the information of the surface-water environment. Then, the dispersion degree, the homodromous degree, and district-difference degree are introduced to increase the cooperation of the multi-AUV system. Finally, the target hunting is solved by embedding the three kinds of degree into the potential field function. The simulation results show that the proposed approach is applicable and feasible for multi-AUV cooperative target hunting

A Mine Main Fans Switchover System with Lower Air Flow Volatility based on Improved Particle Swarm Optimization Algorithm

A reliable ventilation system is essential for maintaining a comfortable working environment and ensuring safety production in an underground coal mine. The automated fan switchover technique was developed for changing the main fan for maintenance with lower air flow volatility of underground mine in the switchover process. This article established the optimization model in the main fans switchover process, used the improved particle swarm optimization algorithm to solve the model, and achieved minimum air flow volatility in the fans switchover process. Compared to previous studies, computer simulations have shown that the proposed algorithm can effectively find the global optimal solution with less initial parameters and achieved lower air flow volatility in underground mine. The particle swarm optimization solution, searching diversity, prevents it from confining to local optimal solutions and enhances convergence. The reasonable step length is beneficial to reduce the air flow volatility and main fans switchover time. The air flow volatility is larger comparatively when some doors are nearly open or closed fully at the start—stop phase of the switchover process. A case application in a China\u27s domestic coal mine shows that the air flow volatility of the underground mine in the main fans switchover process is no more than 0.4%

Multi-AUV Cooperative Target Hunting Based on Improved Potential Field in a Surface-Water Environment

In this paper, target hunting aims to detect target and surround the detected target in a surface-water using Multiple Autonomous Underwater Vehicles (multi-AUV) in a given area. The main challenge in multi-AUV target hunting is the design of AUV’s motion path and coordination mechanism. To conduct the cooperative target hunting by multi-AUV in a surface-water environment, an integrated algorithm based on improved potential field (IPF) is proposed. First, a potential field function is established according to the information of the surface-water environment. Then, the dispersion degree, the homodromous degree, and district-difference degree are introduced to increase the cooperation of the multi-AUV system. Finally, the target hunting is solved by embedding the three kinds of degree into the potential field function. The simulation results show that the proposed approach is applicable and feasible for multi-AUV cooperative target hunting

Theoretical Analysis of Empirical Mode Decomposition

This work suggests a theoretical principle about the oscillation signal decomposition, which is based on the requirement of a pure oscillation component, in which the mean zero is extracted from the signal. Using this principle, the validity and robustness of the empirical mode decomposition (EMD) method are first proved mathematically. This work also presents a modified version of EMD by the interpolation solution, which is able to improve the frequency decomposition of the signal. The result shows that it can provide a primary theoretical basis for the development of EMD. The simulation signal verifies the effectiveness of the EMD algorithm. At the same time, compared with the existing denoising algorithm, it has achieved good results in the denoising of rolling bearing fault signals. It contributes to the development and improvement of adaptive signal processing theory in the field of fault diagnosis. It provides practical value research results for the rapid development of adaptive technology in the field of fault diagnosis

Association of glucocorticoid receptor gene polymorphism and occupational stress with hypertension in desert petroleum workers in Xinjiang, China

Abstract Background The aim of this study was to investigate the occupational stress and hypertension in desert petroleum workers in Xinjiang, and to analyze the association of occupational stress and glucocorticoid receptor (GR) gene polymorphism with the presence of hypertension. Methods Using cluster sampling, 1280 desert petroleum workers of 3 petroleum fields in Xinjiang Karamay were randomly selected as the target group for this study. According to the inclusion criteria, a total of 1080 workers were included as the baseline for this study. We followed these workers for 2 years to investigate their occupational stress and hypertension. The polymorphism of GR gene was detected by polymerase chain reaction-restriction fragment length polymorphism. We applied appropriate statistical methods to analyze the association of occupational stress and glucocorticoid receptor (GR) gene polymorphism with the presence of hypertension. Results After 2 years of follow-up, there were 995 desert petroleum workers in the queue. The study showed that the incidence of hypertension in desert petroleum workers were 19.4%. Compared with the baseline data, the level of occupational stress increased, and with the increase of occupational stress, the incidence of hypertension was gradually increasing. A positive relationship was observed in the GR BCL1 gene polymorphisms and hypertension. Relative to the CC genotype, carries of the GG genotype had a significantly higher risk of hypertension (OR = 2.830). With the combination of genotype CG and GG, carries of CG and GG increased the risk of hypertension (adjusted OR = 2.238, 95%CI:1.104–4.940). There was no significant association between GR G678S gene polymorphisms and hypertension. Conclusion GR gene polymorphism and occupational stress of desert petroleum workers were important risk factors for hypertension