Results 51 to 60 of about 230,931 (257)
Model Motion Control Simulation and Implementation of WDPSS Support in Wind Tunnel Test [PDF]
, 2015 摘要 绳牵引并联机构WDPSS是一种新型低速风洞试验的模型支撑系统，其因灵活度高、模型支撑刚度大、对流场干扰小等诸多优点而逐渐被认识和认可。本文针对该机构进行了运动控制的建模与仿真，根据风洞试验的要求开发了控制系统相关功能模块，并对视觉系统采集信号进行了有效滤波，为将WDPSS的工程应用奠定了基础。本文完成的研究工作与成果如下所述。 首先，针对WDPSS-8原理样机，进行了运动学与动力学分析。通过运动学逆解分析得出绳长与飞机模型位姿之间的关系，根据驱动系统结构特点建立其动力学模型，利用牛顿 ...
王义龙
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Harnessing social media data to track species range shifts
Conservation Biology, EarlyView.Abstract Biodiversity monitoring programs and citizen science data remain heavily biased toward the Global North. Especially in megadiverse countries with limited biodiversity records, incorporating social media data can help address existing data gaps.
Shawan Chowdhury +15 more
wiley +1 more source
Wind Turbine Modeling and Control Study based on LPV Model [PDF]
, 2015 风能是一种清洁可再生能源，其开发和利用越来越受人们的重视。风力发电机是利用风能发电的设备，近年来，风力发电机逐渐向高效率、高可靠性和大型化发展，使风力发电机的动态模型变得更加复杂。为了使风力发电机平稳可靠运行，提高发电效益，对风力发电机进行建模和控制很有必要。本文针对风力发电机的动态非线性特性，基于LPV模型辨识方法对风力发电机建模，后用辨识所得LPV模型设计MPC控制器，对风力发电机进行变桨距控制。论文的主要工作有： （1）讨论风力发电机的原理模型，分别分析各分块原理模型和一些常用的计算机仿真工具。 （
曹力仁
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Biodiversity‐driven spatial conservation planning to delineate temporally stable regions
Conservation Biology, EarlyView.Abstract The accelerating loss of biodiversity underscores the critical need for effective conservation strategies, particularly in the face of climate change and anthropogenic pressures. We devised a conservation planning framework that adopts a temporal stacking approach to species distribution models and landscape connectivity analyses. These models
Mattia Iannella +5 more
wiley +1 more source
Dianci bileiqi, 2019 雷电流数学模型的选择及仿真分析,对感应雷过电压的研究具有重要的意义。对目前感应雷过电压研究领域应用广泛的双指数函数模型,Heidler函数模型,脉冲函数模型3个函数模型,从雷电流的全波、波头两个方面做仿真分析,一阶导数做理论分析,并引入更加精确的双Heidler模型,进行对比分析。总结4种模型各自的优缺点,说明双Heidler模型的精确性及可行性,有助于雷电流模型的选择及感应雷过电压的进一步研究。
陈炜炜, 周懋坤, 詹跃东, 王磊
doaj
Research on Innovations of Financial Arbitrage Models for Foreign-Related Enterprises in China [PDF]
, 2016 摘要 本论文研究的是基于中国涉外企业实需的由与中国市场相关的汇率、利率及其衍生品工具组合而成的无风险和低风险套利模型的创新。论文将创新套利模型分3类：1）利率类套利模型；2）外汇远期类套利模型；3）外汇期权类套利模型。 这些模型均涉及跨市场套利，起到了连通弱关联市场的作用，可辅助提升金融市场效率，某些情况下还能成为市场定价工具。 在外贸行业生存愈发困难的大背景下，本论文所研究的课题对提高外贸企业盈利水平也有重要意义。Abstract The aim of this thesis is to ...
陈庚光
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Defining and identifying relevant stakeholders to advance effective conservation
Conservation Biology, EarlyView.The challenge of defining stakeholders in environmental science and an approach for refining existing definitions. Abstract Stakeholder is a contested term that has spawned a multitude of ad hoc definitions. The ambiguity of these definitions has oftentimes impeded transdisciplinary research in environmental governance and conservation science because ...
Milan Büscher +5 more
wiley +1 more source
"fordi før så skreiv æ Å-G". En studie om andreklassingers valg av stavemåter.
, 2023 The purpose of this master's thesis has been to look at the choices students in Year 2 make when spelling words. The students participating in this research are in the transition between phonological and orthographic writing, and the study will focus on how these students adopt different spelling strategies. The assignment's data material is taken from
openaire +1 more source
NS Family Models and Forecast of yield curves in China [PDF]
, 2016 本文针对国内现有利率预测研究仍以计量模型为主的现象，考察具有经济意义背景的NS类拓展模型对我国利率预测的效果，引入带有无套利条件约束的AFNS模型，以银行间国债市场的中债估值为样本数据，选用基于最大似然估计的卡尔曼滤波对DNS、AFNS模型进行参数估计，以随机游走模型作为基准模型，采用逐次迭代的预测方式对三类模型在不同预测步长之下的利率进行测算，以预测值与实际值误差项的均值、标准差和均方根误差作为评判标准，找寻适合我国银行间债券市场的利率预测工具。 比较后发现，在预测步长较小时 ...
郭媛媛
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Scenarios and strategies for future‐proofing ecosystem management under climatic novelty
Conservation Biology, EarlyView.Abstract Climate change is driving unprecedented declines in dominant, habitat‐forming foundation species across marine and terrestrial ecosystems globally. As climatic novelty becomes the norm, ecosystem reassembly will become increasingly common. Predicting and understanding these transitions, and their implications for future ecosystem functioning ...
Lauren T. Toth +14 more
wiley +1 more source