Results 81 to 90 of about 12,210 (170)
野生动物学报, 2023 为了解全球海蛇（Hydrophiinae）的地理分布格局对陆上温度的响应，进一步研究其生存环境与分布丰度模式的关系。从GBIF网站收集全球71种海蛇地理分布信息，划分全球海蛇的高中低丰度区，并划分海蛇的“广布种”和“特有种”，用GIS技术建立物种丰富度模式，获取气候变量数据，对分布丰度和陆上温度生态位宽度进行统计分析。结果显示：有8个区域可被定义为“高丰度区”，22种海蛇可被定义为“广布种”。在高丰度区，部分海蛇加宽陆上温度生态位，部分则收窄生态位；1个物种的局部陆上温度生态位存在地理变异 ...
王湘君 +4 more
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Multi-target vital sign estimation based on sparse representation under complex scenes [PDF]
Focusing on the issue that millimeter-wave radar was difficult to accurately estimate the vital signs of multiple moving targets in complex indoor scenes, a multi-target vital sign estimation method based on sparse representation under complex scenes was
HUANG Zifeng, MA Jiakang, WANG Hongyan
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, 2020 变分模态分解（VMD）广泛应用于故障诊断中，从振动信号中提取故障特征是故障诊断过程中的关键部分。针对强背景噪声和脉冲干扰下滚动轴承早期故障特征难以提取的问题，提出了一种新的基于果蝇优化算法（FOA）的变分模态分解的轴承故障诊断方法。首先，利用果蝇优化算法自适应优化VMD的惩罚参数α和分解数K，获取最优参数组合；然后，对信号进行VMD分解，得到K个模态分量；最后，基于峭度最大化准则选取最优模态分量进行包络解调分析，提取出故障特征频率。通过仿真信号分析 ...
刘畅, 杨建伟, 王衍学
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The proposed method introduces a parameter determination approach based on the minimum Fractal box dimension (FBD) of Variational Mode Decomposition (VMD) components, aiming to address the issue of manual determination of VMD decomposition layers in ...
Min, Yu, Yan, Yu, Yuhang, Pei
core
Multirotor UAV-borne Vital Signs Sensing Using 4D Imaging Radar [PDF]
Unmanned Aerial Vehicle (UAV)-borne radar technology can solve the problems associated with noncontact vital sign sensing, such as limited detection range, slow moving speed, and difficult access to certain areas.
Chengyao TANG +3 more
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Zhendong Ceshi yu Zhenduan为解决变分模态分解（variational mode decomposition，简称VMD）在噪声情况下提取风电机组故障特征时因参数设置的人为经验不足而带来的误差问题及耗费时间的问题，提出一种基于自适应变分模态分解（adaptive variational mode decomposition，简称AVMD）算法的风电机组故障诊断方法。首先，将包络熵‑峭度‑互信息准则（envelope entropy，kurtosis and mutual information，简称EKM）作为黏菌算法（slime
doaj +1 more source
基于用最小二乘法改进的EMD与能量熵融合的断路器机械故障诊断方法
Gaoya dianqi, 2014 笔者针对经验模态分解（EMD）分解结果的准确性对实验结果的影响,利用最小二乘法对EMD进行改进,有效地缓解了EMD固有的端点效应对实验结果的影响。分别对断路器操动机构的正常振动信号和连接臂松动信号进行EMD和小波变换分解,并将能量熵分别应用到改进EMD与小波变换中。通过能量熵值计算分析表明,改进的EMD能量熵值明显大于小波能量熵,因此改进的EMD与能量熵融合法为断路器机械状态识别提供了有益的帮助。
许丹, 于龙, 王玉梅
doaj
A ISAR Imaging Method for Space Targets Based on Fast Estimation of Joint Motion Parameters [PDF]
Inverse Synthetic Aperture Radar (ISAR) is an important tool for imaging and monitoring space targets. The large rotation angle of space targets can exacerbate the phenomenon of Migration Through Resolution Cells (MTRC), seriously affecting the ISAR ...
Chenyu LIU +5 more
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A Two-Modal Weather Classification Method and Its Application in Photovoltaic Power Probability Prediction [PDF]
Weather classification is an indispensable preprocessing step in photovoltaic (PV) power prediction. A new two-modal weather classification methods based on PV power clustering was proposed to finely depict the uncertainty of PV power output.
FU Xiaobiao +9 more
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Dianci bileiqi当架空线路遭受雷击时，故障行波中存在丰富的故障信息，从暂态分量中准确提取特征量并分类是雷击故障识别的核心。提取过程中会存在模态混叠、最优小波基问题，同时雷击距离、落雷点与短路点不一致也会影响识别效果。针对上述问题，本研究提出了一种KL散度(Kullback-Leibler divergence)改进变分模态分解(Variational Mode decomposition,VMD)的雷击故障识别方法。依据实际故障搭建了220 kV架空线路模型，模拟绕击、反击和短路场景，选取三相电压进行凯伦贝尔 ...
刘举成 +6 more
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