Results 11 to 20 of about 990,138 (190)
Gaoya dianqi, 2021 对GIS的振动信号进行分析可以及时有效的发现设备中存在的故障。在GIS设备的故障诊断中,特征提取是最为关键的步骤,文中针对单一种类的特征提取方法提取到的特征容易缺乏特异性这一缺点,提出了基于复合特征的GIS振动信号特征提取方法。首先将奇异值分解和基于总体最小二乘准则的旋转不变技术这两种时频法结合起来对振动信号中具有明确物理意义的特征量进行提取,对于没有明确物理意义的特征量,通过数据序列法中的变分模态分解和多重分形来对其进行提取;然后将这两种特征量组合得到新的特征量 ...
马星光 +5 more
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, 1999 在计算很多特征向量导数时, 以Nelson法为代表的直接法都显出效率低下, 第二作者为此发展了直接法的一个分支—动柔度法。本文虽是动柔度法的继续, 但就非重特征值情况而言, 它是一种最好的动柔度法, 因为它像Fox法一样, “ 一步求解”便可获得通解, 然而它又不存在Fox法的缺点—支配方程的系数阵为满阵, 所以说, 在计算很多非重特征值的特征向量导数时, 简单动柔度法不仅在计算步骤上比Nelson法简单 ...
张德文, 刘俊
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Fear of Feral Predators Alters Nutritional Responses in Desert Lizards 对野生捕食者的恐惧改变了沙漠蜥蜴的营养响应
Wildlife Letters, EarlyView.Conservation actions meant to support vultures in the Thar desert of India attract large numbers of feral dogs, endangering native prey including the vulnerable Saara hardwickii. Lizards in high‐risk areas eat less food and do not change diet composition but retain more carbon and nitrogen from their diet.
Mihir Joshi, Dror Hawlena, Maria Thaker
wiley +1 more source
, 2012 研究了张量与张量转置的特征值问题,证明了张量的mode-pi特征对与张量p-转置的mode-i特征对是相同的,通过例子说明了张量与张量p-转置的mode-i特征值不一定相等,当mode-i特征值μi和mode-j特征值μj不相等时,对应的特征向量也不一定正交.从而说明了矩阵特征值的性质并不能完全推广到张量情形.此外,还给出了张量与张量p-转置的mode-i特征对相等时指标向量p需要满足的条件.国家自然科学基金项目（１０９６１０１０）；贵州省科学技术基 金项目（黔科合Ｊ字ＬＫＳ［２００９ ...
刘智秉, 陈震, 卢琳璋
core
Functional Ecology, EarlyView.Read the free Plain Language Summary for this article on the Journal blog. Abstract Soil salinization and alkalization often suppress microbial functional activity, triggering negative feedback loops in microbial metabolism, degrading nutrients and agricultural productivity.
Yuqi Chen, Lingying Xu, Xu Zhao
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A systematic review of avian influenza virus transmission models: Gaps and opportunities
Methods in Ecology and Evolution, EarlyView.Abstract Highly pathogenic avian influenza virus (HPAIV) increasingly threatens wild birds, poultry, non‐human mammals and humans, yet gaps and opportunities in avian influenza virus (AIV) transmission modelling have not been comprehensively synthesized.
Shenglai Yin +7 more
wiley +1 more source
Taxonomic and functional diversity of urban bees of the world
Conservation Biology, EarlyView.Abstract Bees play a pivotal role in terrestrial environments. Urbanization can affect these organisms and the ecosystem services they provide. However, knowledge of the global diversity of urban bees is limited. Thus, we summarized data on urban bee species identities and occurrences; compared distributions of all bees with those found in urban ...
João C. F. Cardoso +10 more
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Institutional lessons from the Nordic management model
Conservation Biology, EarlyView.Abstract To improve wildlife management outcomes, in terms of reaching management goals and increasing legitimacy, Nordic countries have developed institutional systems involving stakeholders that aim for a more inclusive and participatory model.
Jens Nilsson +2 more
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Comprehensive and representative conservation planning for biodiversity of ice‐free Antarctica
Conservation Biology, EarlyView.Abstract Antarctica is designated as a natural reserve devoted to peace and science, with Antarctic Specially Protected Areas (ASPAs) serving as the primary instrument for area‐based biodiversity protection. However, the existing ASPA network lacks the comprehensiveness and representativeness required under Annex V, Article 3(2), of the Madrid Protocol.
Wen Wen +3 more
wiley +1 more source
Gaoya dianqi, 2016 针对高压断路器操作机构状态评估过程中线圈电流特征量维数过高的问题,提出了一种基于皮尔森相关系数的特征量优化方法。利用提取的线圈电流特征量构造皮尔森相关系数矩阵,通过分析线圈电流8个特征量间的相关性,并进行特征量优化,得到具有较高分类能力的3个特征量。将优化后的特征量输入神经网络进行高压断路器操作机构的状态评估。实例分析表明特征量优化方法有效降低了特征量的维数,简化了分类器结构,以较少特征量达到了较理想的高压断路器操作机构状态评估效果。
荣强 +4 more
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