Results 41 to 50 of about 16,500 (146)

Effect of uneven tolerance to human disturbance on dominance interactions of top predators

open access: yesConservation Biology, Volume 39, Issue 2, April 2025.
Abstract Anthropogenic activities may alter felid assemblage structure, facilitating the persistence of tolerant species (commonly mesopredators), excluding ecologically demanding ones (top predators) and, consequently, changing coexistence rules. We aimed to determine how human activities influence intraguild relationships among top predators and ...
Pablo Villalva   +2 more
wiley   +1 more source

多种敷设方式下集群电缆的直流载流量仿真研究

open access: yesGaoya dianqi, 2022
为了研究集群电缆敷设方式、回路间距、回路数以及排列方式对交流集群电缆直流载流量的影响,以10 kV交流配电网中广泛使用的三芯交联聚乙烯(XLPE)电缆为例,通过有限元仿真软件建立集群电缆的温度场和流场耦合仿真模型,得到了直埋敷设、排管敷设和沟槽敷设下集群电缆以双极式直流拓扑结构运行时的直流载流量、温度分布和流场分布。结果表明:随着回路间距和回路数的增大,集群电缆载流量的变化速率逐渐减小。直埋敷设下集群电缆之间的热场相互作用最大,而沟槽敷设下集群电缆之间的热场相互作用最小 ...
王启隆   +3 more
doaj  

Uncovering Xi Jinping's Policy Agenda: Text As Data Approach

open access: yesThe Developing Economies, Volume 63, Issue 1, Page 9-46, March 2025.
How many agendas has Xi Jinping put forth and promoted since taking office in 2012, and what are the types of agendas? How much of political attention has each agenda received, and how has the allocation of attention changed over time? We utilize a dataset of presidential statements, speeches, and reports from 2012 to 2022 and employed automated text ...
Jaehwan Lim, Asei Ito, Hongyong Zhang
wiley   +1 more source

Examining the structure of plant–lemur interactions in the face of imperfect knowledge

open access: yesConservation Biology, Volume 39, Issue 1, February 2025.
Abstract Biotic interactions, such as plant–animal seed dispersal mutualisms, are essential for ecosystem function. Such interactions are threatened by the possible extinction of the animal partners. Using a data set that includes plant–lemur interactions across Madagascar, we studied the current state of knowledge of these interactions and their ...
Jadelys Tonos   +6 more
wiley   +1 more source

基于ERA和Gabor最优分解的结构阻尼比识别方法

open access: yesZhendong Ceshi yu Zhenduan
针对密集模态情况下难以有效识别结构阻尼比的问题,提出了一种基于特征系统实现算法(eigensystem realization algorithm,简称ERA)和Gabor最优分解的结构阻尼比识别方法。首先,采用结构自由振动响应,利用特征系统实现算法对结构频率进行识别,得到结构各阶频率的最小差异,并根据Gabor分解的时频分辨率确定Gabor分解的参数取值范围;其次,根据Gabor分解幅值曲线的线性拟合残差标准值,提出基于残差标准值最小化的Gabor形状参数确定原则 ...
doaj   +1 more source

变压器油中溶解气体在线监测装置运行质量指标及评价体系

open access: yesGaoya dianqi, 2021
变压器油中溶解气体在线监测是对油浸式变压器绝缘状况进行实时监测的有效技术手段。对油中溶解气体在线监测装置进行运行质量评价,对装置选型、供应商评价和保障变压器运行可靠性具有重要意义。现有的变电在线监测装置运行质量评价研究存在数据规模小和评价指标有限等问题。为提高评价水平,文中统计分析了大型数据集中在线监测装置的厂家分布、运行年限分布、数据质量等重要信息,然后建立了油中溶解气体在线监测装置运行质量的模糊层次综合评价模型;最后对数据集进行评价结果分析统计,证明了该评价体系反映各厂家监测装置实际应用情况的准确性。
刘慧鑫   +4 more
doaj  

Routine 36‐week scan: prediction of small‐for‐gestational‐age neonate

open access: yesUltrasound in Obstetrics &Gynecology, Volume 65, Issue 1, Page 20-29, January 2025.
ABSTRACT Objectives First, to compare the predictive performance of routine ultrasonographic estimated fetal weight (EFW) at 31 + 0 to 33 + 6 and 35 + 0 to 36 + 6 weeks' gestation for delivery of a small‐for‐gestational‐age (SGA) neonate. Second, to compare the predictive performance of EFW at 36 weeks' gestation for SGA vs fetal growth restriction ...
S. Adjahou   +5 more
wiley   +1 more source

基于Spark的高压断路器机械寿命预测评估

open access: yesGaoya dianqi, 2020
电力系统中高压断路器普遍采用液压操动机构,其机械寿命是考核断路器可靠性和稳定性的基础,文中提出运用数据驱动方法建立退化过程与特征参量之间的数学映射关系,实现高压断路器液压操动机构的机械寿命预测。基于Hadoop+Spark大数据平台及其生态组件,将采集的数据存储在Hadoop分布式文件系统中,利用Spark运算框架处理数据,结合Spark ML机器学习库中的回归算法,训练模型并进行验证评估,从评估结果来看:文中创建的广义线性回归算法模型的均方根误差为52.96,R-平方系数为0.92 ...
段雄英   +4 more
doaj  

FB-YOLOv7

open access: yes
道路头盔和车辆目标检测的最小数据集。完整版可访问地址:https://universe.roboflow.com/helmetdetection-beozr/helmet-detection-wwlwvhttps://universe.roboflow.com/yolov3-zkcgl/daylight ...
Minjie Fang (18456417)
core   +1 more source

Linking extinction risk to the economic and nutritional value of sharks in small‐scale fisheries

open access: yesConservation Biology, Volume 38, Issue 6, December 2024.
Abstract To achieve sustainable shark fisheries, it is key to understand not only the biological drivers and environmental consequences of overfishing, but also the social and economic drivers of fisher behavior. The extinction risk of sharks is highest in coastal tropical waters, where small‐scale fisheries are most prevalent.
Andrew J. Temple   +7 more
wiley   +1 more source

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