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基于特征交互和聚类的行为识别方法
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作者 李凯歌 蔡鹏飞 周忠 《计算机辅助设计与图形学学报》 EI CSCD 北大核心 2023年第6期903-914,共12页
针对现有行为识别方法缺乏对时空特征关系建模的问题,提出一种基于特征交互和聚类的行为识别方法.首先设计一种混合多尺度特征提取网络提取连续帧的时间和空间特征;然后基于Non-local操作设计一种特征交互模块实现时空特征的交互;最后... 针对现有行为识别方法缺乏对时空特征关系建模的问题,提出一种基于特征交互和聚类的行为识别方法.首先设计一种混合多尺度特征提取网络提取连续帧的时间和空间特征;然后基于Non-local操作设计一种特征交互模块实现时空特征的交互;最后基于三元组损失函数设计一种难样本选择策略来训练识别网络,实现时空特征的聚类,提高特征的鲁棒性和判别性.实验结果表明,与基线方法TSN相比,所提方法的准确度在UCF101数据集上提高了23.25个百分点,达到94.82%;在HMDB51数据集上提高了20.27个百分点,达到44.03%. 展开更多
关键词 行为识别 时空特征关系 特征交互 特征聚类
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A study on the temporal and spatial characteristics of droughts following earthquakes
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作者 张凯 汤懋苍 高晓清 《Applied Geophysics》 SCIE CSCD 2013年第4期488-495,513,共9页
According to the "jacking-up" theory, which relates the cause of earthquakes to outer core convection ascension bodies, the crust will gradually recover after an earthquake. In such cases, the crust is stretched, th... According to the "jacking-up" theory, which relates the cause of earthquakes to outer core convection ascension bodies, the crust will gradually recover after an earthquake. In such cases, the crust is stretched, the underground temperature is reduced, precipitation decreases, and drought occurs. In this paper, precipitation is compared with ground temperature and seismic data to determine the spatial and temporal relationship between earthquakes and subsequent droughts. Our objective is to develop a new method of drought prediction. With a few exceptions in location, the analysis of the first drought to occur after the Ms 〉 7 earthquakes in China's Mainland and the adjacent areas since 1950 shows that droughts tended to occur in regions near earthquake epicenters and in the eastern regions of the epicenters at the same latitude within six months after the earthquakes. In addition, and the differences between the starting time of the earthquakes and the droughts nearly share the same probability of 0 to 6 months. After careful analysis of 34 Ms 〉 6.5 earthquakes occurring in western China from 1980 to 2011, we determined that a second drought tends to occur approximately six months following the first drought, indicating a quasi-half-year period. Moreover, the duration of the quasi-half-year fluctuation increases with the magnitude of earthquake, at approximately 2.5 years for Ms 6.5 earthquake and approximately 5 years for Ms 8 earthquake. 展开更多
关键词 EARTHQUAKE crust recovery quasi-half-year period epicenter drought area side drought area
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利用浮动车大数据进行稀疏路段行程时间推断 被引量:3
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作者 张发明 朱欣焰 +1 位作者 呙维 胡涛 《武汉大学学报(信息科学版)》 EI CSCD 北大核心 2017年第1期56-62,共7页
针对利用实时浮动车数据估计路段行程时间时存在的数据稀疏性问题,提出了构建三层神经网络模型,以目标路段与邻接路段间的特征关系为输入、目标路段与邻接路段行程时间比值为输出,利用浮动车历史大数据获取路段之间的交通时空关联关系,... 针对利用实时浮动车数据估计路段行程时间时存在的数据稀疏性问题,提出了构建三层神经网络模型,以目标路段与邻接路段间的特征关系为输入、目标路段与邻接路段行程时间比值为输出,利用浮动车历史大数据获取路段之间的交通时空关联关系,继而用于路段行程时间的推断。采用武汉市2014年3~7月的浮动车GPS历史数据进行验证,得到的路段行程时间估计值的平均绝对百分比误差小于25%,证明了所提方法的有效性。 展开更多
关键词 浮动车大数据 数据稀疏性 时空关联关系特征 神经网络 行程时间推断
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