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基于无人机载激光雷达点云数据的人工侧柏林单木分割研究 被引量:4
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作者 李远航 笪志祥 闫烨琛 《西北林学院学报》 CSCD 北大核心 2023年第6期171-179,共9页
可持续的森林经营管理模式有助于实现生态文明建设的高质量发展,人工林单木分割结果的获取是森林经营管理的关键。目前无人机载激光雷达技术为单木位置的精准定位和树冠的精确划分提供了应用空间。利用冠层高度模型(CHM)检测和提取单木... 可持续的森林经营管理模式有助于实现生态文明建设的高质量发展,人工林单木分割结果的获取是森林经营管理的关键。目前无人机载激光雷达技术为单木位置的精准定位和树冠的精确划分提供了应用空间。利用冠层高度模型(CHM)检测和提取单木数量和树冠、树高等信息,评估和分析空间分辨率和点云密度对单木分割和树冠提取结果的影响和精度,该方法可准确分割人工侧柏林和提取树冠信息,总体上单木分割精确率均>75%,树冠轮廓提取精确率均>65%,实测数据与提取数据的回归决定系数均>0.6。适当的空间分辨率有助于提高单木分割精度,当分辨率为0.3 m时单木分割和树冠提取结果均为最优。同时研究发现随着点云密度的降低,单木数量的识别精度值随之下降。当点云密度为100%时,F为89%,当点云密度为10%时,其F降低至73%。基于CHM模型可以较好实现人工林的单木精确分割,对林木出现的树冠重叠、覆盖、偏移等现象均有一定的辨别能力;同时分析了空间分辨率和点云密度对单木分割和树冠提取结果的影响并评估了精确性,识别了单木分割时关键参数的最优选择。 展开更多
关键词 无人机激光雷达 单木分割 结构参数信息 空间分辨率 点云密度
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Geometric Properties of AR(q) Nonlinear Regression Models
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作者 LIUYing-ar WEIBo-cheng 《Chinese Quarterly Journal of Mathematics》 CSCD 2004年第2期146-154,共9页
This paper is devoted to a study of geometric properties of AR(q) nonlinear regression models. We present geometric frameworks for regression parameter space and autoregression parameter space respectively based on th... This paper is devoted to a study of geometric properties of AR(q) nonlinear regression models. We present geometric frameworks for regression parameter space and autoregression parameter space respectively based on the weighted inner product by fisher information matrix. Several geometric properties related to statistical curvatures are given for the models. The results of this paper extended the work of Bates & Watts(1980,1988)[1.2] and Seber & Wild (1989)[3]. 展开更多
关键词 nonlinear regression model AR(q) errors geometric framework statistical curvature Fisher information matrix
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An interval effective independence method for optimal sensor placement based on non-probabilistic approach 被引量:6
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作者 YANG Chen LU ZiXing 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2017年第2期186-198,共13页
This paper presents an interval effective independence method for optimal sensor placement, which contains uncertain structural information. To overcome the lack of insufficient statistic description of uncertain para... This paper presents an interval effective independence method for optimal sensor placement, which contains uncertain structural information. To overcome the lack of insufficient statistic description of uncertain parameters, this paper treats uncertainties as non-probability intervals. Based on the iterative process of classical effective independence method, the proposed study considers the eliminating steps with uncertain cases. Therefore, this method with Fisher information matrix is extended to interval numbers, which could conform to actual engineering. As long as we know the bounds of uncertainties, the interval Fisher information matrix could be obtained conveniently by interval analysis technology. Moreover, due to the definition and calculation of the interval relationship, the possibilities of eliminating candidate sensors in each iterative process and the final layout of sensor placement are both presented in this paper. Finally, two numerical examples, including a five-storey shear structure and a truss structure are proposed respectively in this paper. Compared with Monte Carlo simulation, both of them can indicate the veracity of the interval effective independence method. 展开更多
关键词 optimal sensor placement interval effective independence method non-probabilistic approach interval Fisher information matrix interval possibility
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