Abstract: A method for extracting a black-odorous water body based on a CART classification model includes: selecting a research region, designing sampling points within the region; monitoring relevant chemical indicators of the water body at various sampling points, extracting remote sensing reflectance data of the water body, determining a type of the water body according to a classification standard of relevant chemical indicators for an urban black-odorous water body; comparing and analyzing the remote sensing reflectance data to obtain spectral change features of the black-odorous water body and a general water body; constructing each node of a decision tree according to the spectral change features and based on Gini index, constructing a decision tree classification model to obtain classification results of the black-odorous water body and the general water body, calculating a classification accuracy; analyzing the classification results to obtain spatiotemporal distribution changes of black-odorous water bodies

Abstract: The invention provides a high-water pressure trapdoor model test device and a use method thereof. The high-water pressure trapdoor model test device includes a PIV analysis unit, a liquid material, a solid material, pore water pressure gauges, first soil pressure sensors, second soil pressure sensors, third soil pressure sensors, a test box and a pressurizing unit. A box body of the test box is provided with an opening sealed by a base plate, a hole is formed in the base plate, a trapdoor is arranged at the hole, the third soil pressure sensors are arranged in the trapdoor, the first soil pressure sensors are arranged in the base plate, the solid material is placed on the base plate, the second soil pressure sensors and the pore water pressure gauges are arranged in the solid material, and the liquid material is placed on the solid material.

Abstract: The present disclosure provides a method. and device for radio frequency control of a multichannel wireless modem. The multichannel wireless modem includes N wireless modems, and the method includes: sorting the N wireless modems; acquiring a registering frequency of the 1st wireless modem; for the nth wireless modem, calculating an interfering frequency of the nth wireless modem according to registering frequencies of the 1st to the (n?1)th wireless modems, and registering according to a frequency retrieved by the nth wireless modem to obtain the registering frequency of the nth wireless modem, wherein the registering frequency does not fall into frequency scope of the interfering frequency; starting to execute the step from n=2 and finishing till n=N. The present disclosure achieves that the registering frequencies of the N wireless modems are different, thus avoids co-channel interference and frequency doubling interference and improves sensitivity and transmission rate of the multichannel wireless modem.