Results 31 to 40 of about 4,388 (119)
Deep quantile regression for growth and maturation reaction norms
Methods in Ecology and Evolution, Volume 17, Issue 1, Page 111-124, January 2026.Abstract Understanding species' growth and maturation responses to anthropogenic and environmental pressures is crucial for tracking demographic shifts, phenotypic change and ensuring population sustainability. Traditional regression methods often focus on modelling the conditional mean of life‐history traits, potentially overlooking heterogeneity in ...
Guankui Liu +4 more
wiley +1 more source
Ultrasound in Obstetrics &Gynecology, Volume 66, Issue 6, Page 747-753, December 2025.ABSTRACT Objective Ultrasound‐based fetal growth assessment is an essential part of clinical decision‐making in modern obstetric care. This study aimed to evaluate the impact of maternal and fetal characteristics on the accuracy and precision of sonographic fetal weight estimation.
M. Granfors +4 more
wiley +1 more source
The Political Empowerment of Women and Industrialization in Africa
Politics &Policy, Volume 53, Issue 6, December 2025.ABSTRACT This study examines the effect of political empowerment of women on industrialization in Africa. The results, after controlling for cross‐sectional dependence, show that women's political implication causes industrialization. The fixed effects Driscoll/Kraay standard error and the GMM estimators reveal that women's political empowerment ...
Tii N. Nchofoung +2 more
wiley +1 more source
四川大学学报. 自然科学版, 2006 讨论了误差形式是广义误差分布的随机单位根过程的估计和检验问题.在误差为广义误差分布时对随机单位根过程进行了估计,并利用近似极大似然估计方法构造了相应的检验统计量,同时还得到了统计量在混合相依条件下的极限分布.
毛瑞华, 李竹渝
doaj
基于数据相关性分析的全光纤电流互感器误差状态在线评估方法研究
Gaoya dianqi, 2022 全光纤电流互感器是特高压输电系统中电流测量的关键设备，复杂的物理结构导致其测量误差易受多种因素的影响，稳定性较差。常规的误差检测方法是定期利用标准互感器进行比对测试，无法及时发现误差状态的劣化趋势，且经济性较差。针对这一问题，文中提出了一种基于相关性分析的全光纤电流互感器误差状态评估方法：采集换流站同一测量点下三台全光纤电流互感器的测量数据，在电气物理相关性的约束下，针对全光纤电流互感器的测量数据进行主元分形，将误差评估映射为Q统计量的变化分析。数据分析表明 ...
叶剑涛 +5 more
doaj
Xibei Gongye Daxue Xuebao, 2022 针对高频方波注入法零低速下永磁同步电机无位置传感器控制存在的高频转矩脉动问题, 提出了一种基于双高频方波注入法的双绕组永磁同步电机无位置传感器控制策略。建立永磁同步电机高频数学模型, 分析得到转矩脉动与注入信号的解析关系。对于同相位表贴式双绕组永磁同步电机, 当第一套绕组注入高频方波时, 依据2套绕组的位置关系, 推导了第二套绕组应当注入方波信号的形式, 使同一时刻产生的高频转矩脉动代数和为零, 以消除高频转矩脉动。提取2套绕组高频信号中包含的转子位置估计误差, 比较得到同一时刻误差最小值 ...
ZHOU Qixun +4 more
doaj +1 more source
Ultrasound in Obstetrics &Gynecology, Volume 65, Issue 5, Page 624-632, May 2025.ABSTRACT Objectives Placental insufficiency contributes to many obstetric pathologies, but there is no bedside clinical tool to evaluate placental perfusion. We have developed a method to acquire multiple three‐dimensional (3D) power Doppler (PD) ultrasound (US) volumes of placental vasculature, with infrared camera tracking of the precise spatial ...
A. Xue +5 more
wiley +1 more source
Gaoya dianqi, 2019 基于移动式特高频（UHF）天线阵列的敞开式变电站局部放电巡检与定位系统获得应用,但天线间距一般较小,使放电源距离定位准确度较低。文中提出了基于时差法的放电源波达方向估计方法,利用两对相交天线UHF信号入射角与方位角、俯仰角的几何关系,推导得到方位角与俯仰角的计算公式;为了分析时差误差对方位角及俯仰角估计误差的影响,建立了基于蒙特卡罗法的波达方向估计误差仿真模型,进而对放电源位置、阵列尺寸及天线阵列布置对方位角与俯仰角估计准确度的影响进行分析;实验测试了方位角与俯仰角的估计准确度,最后将其应用于现场220
徐越峰 +6 more
doaj
Landscape‐scale predictions of future grassland conversion to cropland or development
Conservation Biology, Volume 39, Issue 1, February 2025.Abstract Grassland conservation planning often focuses on high‐risk landscapes, but many grassland conversion models are not designed to optimize conservation planning because they lack multidimensional risk assessments and are misaligned with ecological and conservation delivery scales.
Kevin W. Barnes +2 more
wiley +1 more source
Jixie chuandong, 1989 文中介绍了圆柱齿轮齿面误差采用三座标测量和二维信号处理的测量和数据处理方法,提出了改进的二维Kimura谱估计并用于估计斜齿轮齿面周期误差的频率成份。实验分析表明:（1）改进的Kimura谱估计有尖锐的谱峰和高的分辨率;（2）齿面误差的功率谱估计能很好的揭示圆柱齿轮齿面波形的特征和诊断机床一刀具一工件系统的主要周期误差源。这对齿轮自动化生产中的测量和精度改善是很有实际意义的。
余忠华, 吴昭同
doaj