Results 51 to 60 of about 10,420 (169)
Noise Cancellation in Knee Joint Vibration Signals [PDF]
, 2013 膝关节（knee-joint）是人体下肢的主要关节，是人体关节中最大的也是结构和功能最复杂的关节，同时也是人体最容易损伤的关节之一。膝关节损伤的早期诊断有助于预防退行性骨性关节炎（osteoarthritis），以便于患者能尽早接收治疗，减缓其关节退化的过程。膝关节摆动信号（vibroarthrographicsignal，VAG）是膝关节在伸展和弯曲运动中发出的摆动声音信号，是一种复杂的非平稳信号。膝关节摆动信号能够描述关节内损伤状况，是一种非侵入性的膝关节疾病诊断手段。然而 ...
鹿猛
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The influence of social identity on attitudes toward wildlife
Conservation Biology, Volume 38, Issue 4, August 2024.Abstract Wildlife conservation depends on supportive social as well as biophysical conditions. Social identities such as hunter and nonhunter are often associated with different attitudes toward wildlife. However, it is unknown whether dynamics within and among these identity groups explain how attitudes form and why they differ.
Max H. Birdsong +4 more
wiley +1 more source
Gaoya dianqi, 2009 为了准确地检测出高压断路器的故障类型,笔者首次将经验模态分解（EMD）方法引入高压断路器的振动信号分析当中,并提出将EMD分解得到的固有模态函数（IMF）能量熵值作为表征断路器故障类型的新特征向量。为了证实该分析方法的有效性,笔者在实验室的110 kV SF6断路器上进行了模拟实验,提取了正常和故障状态下振动信号的IMF能量熵值特征向量,并以此作为径向基神经网络的输入向量。最后,引入置信度的概念,对径向基神经网络的输出结果进行评价。该方法基于实验室研究取得了较好的识别效果 ...
陈伟根, 邓帮飞, 杨彬
doaj
Marine motor fault diagnosis based on CEEMDAN and BRECAN under strong noise conditions [PDF]
ObjectiveThe background noise in the engine room during actual ship navigation leads to the poor accuracy in fault diagnosis methods. To address this issue, this paper proposes a ship motor fault diagnosis method based on complementary ensemble empirical
Chong YAO +3 more
core +1 more source
Wildlife Letters, Volume 2, Issue 1, Page 5-16, March 2024.Corcovado National Park in Costa Rica is an important ecotourism site. During the COVID‐19 lockdown, we studied the impact of human visitation on wildlife using camera traps on walking trails, comparing closed (control) and open (experimental) trails, pre‐ and post‐lockdown. We assessed activity patterns and photo rates of 13 species. Wildlife behavior
Juan C. Cruz‐Díaz +5 more
wiley +1 more source
A hybrid image watermarking algorithm based on BEMD,DCT and SVD(基于BEMD、DCT和SVD的混合图像水印算法)
Zhejiang Daxue xuebao. Lixue ban, 2023 水印的不可见性和算法的鲁棒性是图像版权保护领域关注的重要问题，然而大多数算法不能很好地平衡二者的关系。为此，提出了一种基于二维经验模态分解（BEMD）、离散余弦变换（DCT）和奇异值分解（SVD）的不可见性高、鲁棒性强的混合图像水印算法。首先，对水印图像采用Arnold置乱，增强算法的安全性，并对置乱后的水印图像进行二维DCT。然后，对宿主图像进行BEMD，得到有限个尺度不同的内蕴模态函数（IMF）及余量，选择与宿主图像相关性较低的IMF执行二维DCT，根据水印的大小对其进行不重叠分块 ...
谭晓东(TAN Xiaodong) +3 more
doaj +1 more source
Zhendong Ceshi yu Zhenduan针对煤矿锚杆钻车姿态估计中惯性导航的多源噪声，提出一种基于噪声敏感先验的改进变分模态分解（variational mode decomposition，简称VMD）惯导异构信号降噪方法。首先，利用加速度和角速度时频域参数特性变化，探究捷联惯导异构信号的噪声敏感差异和多源噪声作用规律；其次，根据异构信号噪声敏感先验和最大峭度变化趋势，构建双分解层，并通过能量波动模型监测在不同分解层下模态分量的能量变化，避免参数固定造成的过分解和欠分解问题，实现对惯导异构信号同步VMD分解；然后，根据皮尔逊相关系数 ...
doaj +1 more source
Gaoya dianqi, 2017 文中搭建了真空断路器试验平台,实现了主轴卡涩等四类机械故障状态。通过将正常及故障状态下的实测振动信号进行经验模态分解,得到所需要的内禀模态函数（intrinsic made function,IMF）,利用能量法求出包含主要故障特征信息的各内禀模态函数分量的能量总量。利用IMF分量能量总量作为特征向量,并以此作为支持向量机输入,分析对比了不同分类策略、核函数的分类时间和分类准确率,经实验分析选用"一对其他"分类策略并且核函数为径向基函数的分类效果最优 ...
冯英 +5 more
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Gaoya dianqi, 2023 随着电力系统中变压器容量的不断增加，变压器绕组松动缺陷引起的影响也愈发严重，故需进行故障诊断。针对利用振动信号进行变压器绕组松动缺陷诊断问题，提出基于变分模态分解（VMD）排列熵（PE）的变压器振动信号特征提取方法与天牛须搜索（BAS）优化支持向量机（SVM）的变压器绕组松动缺陷诊断方法。首先对一台实际110 kV变压器设置不同松动状态，采集绕组正常与不同松动程度状态下振动信号；其次，采用变分模态分解结合排列熵进行变压器绕组松动缺陷特征提取；再次，采用天牛须搜索优化支持向量机算法进行绕组松动状态模式识别。
顾仲翔 +4 more
doaj
Research on landslide deformation rate prediction method based on dynamic serial PSO-BiLSTM [PDF]
This paper proposed a method for predicting landslide deformation rates using a dynamic serial PSO-BiLSTM approach, aiming to overcome the limitation such as insufficient accuracy and low computational efficiency found in existing methods. Initially, the
Liqiu HE, Rui CAO, Yufeng TANG
core +1 more source