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Spot segmentation is an important section of detecting coal level of coal bin in computer vision. When it is difficult to proceed, analyze and locate the spot position for the image obtained under the condition of low contrast and strong noise. This paper aim at achieving spot segmentation in complex underground, a novel spot segmentation method based on nonsubsampled contourlet transform (NSCT) and...
This paper put forward a new model to analyze the grounding effect on common mode interference of underground PWM inverter. Taking into account the grounding method,the author establishs a common mode equivalent circuit of underground inverter.After Comparison of calculation results by Matlab software simulation,it can be conclude that ungrounded neutral of transformer could redue common mode current...
A cost effective ZigBee-based wireless mine supervising system is presented in this article. This scheme used intelligent helmets as voice terminal and ultra-low-power nodes of wireless sensor network.The programme adopted ZigBee wireless technology to build wireless sensor networks, realized real-time surveillance with early-warning intelligence on methane, temperature, humidity in mining area, and...
The parameter of the rectangular tunnel have greatly influence on the radiation characteristics of a electric dipole. The expression of the electric and magnetic Hertz vectors in vertical direction was deduced by the method of the Fourier Transform. Based on the MATLAB software, the field strength against different environment was studied. The main conclusions are as follows: for the horizontal dipole,...
The model of the coal mine tunnel is established in practice. The rectangular tunnel is divided into two parallel slot waveguides by electric field distributing, the refraction loss is approximately figured out. Results will agree satisfactorily with geometry optics when frequency is increasing.
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