In order to address the issues of the current sheep face pain detection algorithm under complex environments with poor detection accuracy and complex models,this paper proposes a two-stage method of sheep face pain de...In order to address the issues of the current sheep face pain detection algorithm under complex environments with poor detection accuracy and complex models,this paper proposes a two-stage method of sheep face pain detection based on light yolov5s.First,the weights of the yolov5s model are reduced by combining the Ghostnet structure,feature fusion is performed using the BiFPN structure and the ODConv join to improve detection accuracy.The experimental results show that the number of parameters and complexity of the optimized model are reduced by 38.03%and 50.94%,respectively,compared with the original model,and the accuracy of recognizing sheep faces is improved by 0.2%and the recall rate is increased by 1%.Compared to current mainstream algorithms such as yolov4 tiny and SSD,it not only significantly reduces the number of parameters but also has a better detection performance.Second,pain detection of sheep faces recognised by lightweight yolov5s was carried out by MobileNetV2,and experimental results showed that MobileNetV2 achieved a mean classification accuracy of over 98%for painful sheep,and this illustrates that this two-stage sheep face pain recognition research method has great application value for sheep health breeding.展开更多
To avoid the machine problems of excessive axial force, complex process flow and frequent tool changing during robotic drilling holes, a new hole-making technology (i.e., helical milling hole) was introduced for desig...To avoid the machine problems of excessive axial force, complex process flow and frequent tool changing during robotic drilling holes, a new hole-making technology (i.e., helical milling hole) was introduced for designing a new robotic helical milling hole system, which could further improve robotic hole-making ability in airplane digital assembly. After analysis on the characteristics of helical milling hole, advantages and limitations of two typical robotic helical milling hole systems were summarized. Then, vector model of helical milling hole movement was built on vector analysis method. Finally, surface roughness calculation formula was deduced according to the movement principle of helical milling hole, then the influence of main technological parameters on surface roughness was analyzed. Analysis shows that theoretical surface roughness of hole becomes poor with the increase of tool speed ratio and revolution radius. Meanwhile, the roughness decreases according to the increase of tool teeth number. The research contributes greatly to the construction of roughness prediction model in helical milling hole.展开更多
Based on the previous research on the model of rainstorm weather with low-level jet in Xiangtan,using the classification result of radar echo characteristics,the wind profile data provided by new generation of weather...Based on the previous research on the model of rainstorm weather with low-level jet in Xiangtan,using the classification result of radar echo characteristics,the wind profile data provided by new generation of weather radar in Changsha and hourly rainfall data,a thorough study of the heavy rainfall from 2 to 5 July 2016 in Xiangtan was conducted. It was concluded that heavy precipitation had the characteristics of the WPSH pattern of rainstorm with low-level jet at early stage,and then it converted to cold shear jet pattern in latter stage. When low-level southwest jet began to have momentum download,that is to say,there was more than 12 m/s of southwest jet below 1 km,and it rapidly strengthened and expanded downward,it was conducive to the occurrence of short-term rainstorm. The low-level jet would not immediately cause a strong precipitation when it reached the station,with a certain lag. A positive correlation existed between the increase of low-level jet index and precipitation intensity,and low-level jet index could predict the occurrence of heavy rainfall and rain intensity.展开更多
文摘In order to address the issues of the current sheep face pain detection algorithm under complex environments with poor detection accuracy and complex models,this paper proposes a two-stage method of sheep face pain detection based on light yolov5s.First,the weights of the yolov5s model are reduced by combining the Ghostnet structure,feature fusion is performed using the BiFPN structure and the ODConv join to improve detection accuracy.The experimental results show that the number of parameters and complexity of the optimized model are reduced by 38.03%and 50.94%,respectively,compared with the original model,and the accuracy of recognizing sheep faces is improved by 0.2%and the recall rate is increased by 1%.Compared to current mainstream algorithms such as yolov4 tiny and SSD,it not only significantly reduces the number of parameters but also has a better detection performance.Second,pain detection of sheep faces recognised by lightweight yolov5s was carried out by MobileNetV2,and experimental results showed that MobileNetV2 achieved a mean classification accuracy of over 98%for painful sheep,and this illustrates that this two-stage sheep face pain recognition research method has great application value for sheep health breeding.
基金Foundation item： Projects（50975141, 51005118） supported by the National Natural Science Foundation of China Projects（20091652018, 2010352005） supported by Aviation Science Fund of China Project（YKJ11-001） supported by Key Program of Nanjing College of Information Technology Institute, China
文摘To avoid the machine problems of excessive axial force, complex process flow and frequent tool changing during robotic drilling holes, a new hole-making technology (i.e., helical milling hole) was introduced for designing a new robotic helical milling hole system, which could further improve robotic hole-making ability in airplane digital assembly. After analysis on the characteristics of helical milling hole, advantages and limitations of two typical robotic helical milling hole systems were summarized. Then, vector model of helical milling hole movement was built on vector analysis method. Finally, surface roughness calculation formula was deduced according to the movement principle of helical milling hole, then the influence of main technological parameters on surface roughness was analyzed. Analysis shows that theoretical surface roughness of hole becomes poor with the increase of tool speed ratio and revolution radius. Meanwhile, the roughness decreases according to the increase of tool teeth number. The research contributes greatly to the construction of roughness prediction model in helical milling hole.
基金Supported by Forecasters' Special Project of Hunan Meteorological Bureau in 2016(XQKJ16C003)
文摘Based on the previous research on the model of rainstorm weather with low-level jet in Xiangtan,using the classification result of radar echo characteristics,the wind profile data provided by new generation of weather radar in Changsha and hourly rainfall data,a thorough study of the heavy rainfall from 2 to 5 July 2016 in Xiangtan was conducted. It was concluded that heavy precipitation had the characteristics of the WPSH pattern of rainstorm with low-level jet at early stage,and then it converted to cold shear jet pattern in latter stage. When low-level southwest jet began to have momentum download,that is to say,there was more than 12 m/s of southwest jet below 1 km,and it rapidly strengthened and expanded downward,it was conducive to the occurrence of short-term rainstorm. The low-level jet would not immediately cause a strong precipitation when it reached the station,with a certain lag. A positive correlation existed between the increase of low-level jet index and precipitation intensity,and low-level jet index could predict the occurrence of heavy rainfall and rain intensity.
