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多维特征GS-SVM地下空间激光点云分割
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作者 卫梦莎 龚云 +1 位作者 张小宇 刘腾飞 《测绘通报》 CSCD 北大核心 2024年第9期117-122,共6页
针对激光点云在弱光和低特征点环境的点云分割中过拟合问题,本文提出了一种基于网格搜索的多项式核最小二乘支持向量机(GS-SVM)点云分割算法,提取点云的多维特征,并分别对车辆、车道线和车库障碍物柱子等多维特征进行分类;采用多尺度精... 针对激光点云在弱光和低特征点环境的点云分割中过拟合问题,本文提出了一种基于网格搜索的多项式核最小二乘支持向量机(GS-SVM)点云分割算法,提取点云的多维特征,并分别对车辆、车道线和车库障碍物柱子等多维特征进行分类;采用多尺度精度评估指标验证特征选取的有效性并评估分割算法。结果表明,与文献中传统分类算法的柱子识别率80%和车辆识别率65%相比,基于多项式核函数的分类算法对柱子和车辆的识别率分别在75%和73%以上,提高了5%和8%;在使用其他两个核函数时,GS-SVM同样保持了优势。本文算法相对于常规算法有较强的稳健性,为其在弱光和地理特征点环境的点云分割问题提供了解决方案,丰富了激光雷达三维扫描的使用场景。 展开更多
关键词 点云分类 机器学习 GS-SVM SMRF滤波算法 激光雷达扫描
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Ten ring-B aromatized ergosterols from Aspergillus spectabilis
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作者 wei mengsha SUN weiguang +9 位作者 LIU Linlin LI Yongqi LI Lanqin LI Qin CHEN Yu GUO Jieru GU Lianghu ZHU Hucheng CHEN Chunmei ZHANG Yonghui 《Chinese Journal of Natural Medicines》 SCIE CAS CSCD 2024年第7期654-662,共9页
Spectasterols F−O(1−10),ten interesting ergosterols with an aromatized B ring,were obtained from Aspergillus spectabilis.Their structures and absolute configurations were determined using a combination of high-resolut... Spectasterols F−O(1−10),ten interesting ergosterols with an aromatized B ring,were obtained from Aspergillus spectabilis.Their structures and absolute configurations were determined using a combination of high-resolution electrospray ionization mass spectrometry(HR-ESI-MS),nuclear magnetic resonance(NMR)spectroscopy,single-crystal X-ray diffraction analyses,and electronic circular dichroism(ECD)calculations.Structurally,these aromatic ergosterols feature versatile side chains.Notably,compound aromatic ergosterols featured versatile side chains,and compound 4 is an unusual C23 ergosterol characterized by a shorter side chain due to oxidative cleavage between C-23 and C-24.All compounds were evaluated for their neuroprotective activities,with compound 8 showing a dose-dependent ability to reduce apoptosis and protect mitochondrial function in glutamate-induced SH-SY5Y cells. 展开更多
关键词 STEROIDS Aspergillus spectabilis Aromatic ergosterols Neuroprotective activities Structure elucidation
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