Results 31 to 40 of about 69,960 (229)
Variable Selection and Direction Estimation for Single-index Models via Distance Covariance [PDF]
, 2016 在本文中，我们提出了两种在单指标模型中同时进行变量选择和参数估计的方法：最大化带惩罚项的距离协方差法(PeDcov)和带阀值梯度正则化方法优化距离协方差法(DC-TGDR)。在最大化单指标和响应变量之间距离协方差的过程中，通过惩罚或正则化单指标方向参数，我们可以有效的筛选出重要变量，并排除无关变量。与文献中已有的方法相比，新提出的两种方法从充分降维的角度出发，避免了非参数联系函数的估计，且可以解决响应变量是离散变量时的方向参数估计问题。再者，新提出DC-TGDR方法鼓励变量成组选择 ...
刘西
core
Rare Metals, EarlyView.ABSTRACT Regulating negative parameters of metacomposites is mainly limited by their unclear mechanisms, which affects their practical applications in new sensing, communication, electromagnetic (EM) protection and other fields. This work proposes a dual‐functional competitive design strategy based on the waste corncob‐derived carbon/polyaniline ...
Qiuyun Yang +4 more
wiley +1 more source
Dizhen xuebao, 2021 本文随机选取了100条具有不同地震动峰值特征参数的地震动记录，通过基线校正、积分等方法获取每条地震动的峰值加速度（PGA）、峰值速度（PGV）和峰值位移（PGD）三个参数，进而基于有限元数值模拟，通过对比同一个观测点不同峰值特征参数的特性与不同观测点同一峰值特征参数的特性来研究土坡的地震响应规律，分析各地震动峰值特征参数与土坡地震响应的相关性。计算结果表明：PGA，PGV和PGD与土坡地震响应都具有良好的正相关性，其相关性系数平均值分别为0.868，0.981，0.926 ...
Lurong Du +3 more
doaj +1 more source
Greenhouse gas emissions from croplands of China [PDF]
, 2003 China possesses cropland of 1.33 million km 2. Cultivation of the cropland not only altered the biogeochemical cycles of carbon (C) and nitrogen (N) in the agroecosystems but also affected global climate.
Bohan, Liao +13 more
core +1 more source
Rare Metals, EarlyView.ABSTRACT The Schottky barrier height (SBH), which serves as a pivotal determinant of charge carrier injection efficiency in electronic devices, critically governs electrical behavior at metal/semiconductor interfaces. However, pronounced metal‐induced gap states at metal contact interfaces induce Fermi‐level pinning, which constrains the ...
Xiaofei Liu +10 more
wiley +1 more source
Gaoya dianqi, 2005 电力工程上不但需要知道互感线路的零序集总参数, 有时还需要知道分布参数。通过对线路端电气量的同步测量,可以计算得到线路的集总参数,继而可以分别对互感部分和非互感部分求取线路的分布参数。笔者首先给出了输电线路分布参数模型和集总参数模型之间的转化公式;在此基础上,提出了互感线路分布参数在线测量方法,并通过仿真试验对所提出的方法进行了验证。
郭建全 +4 more
doaj
Using porous metals to enhance heat transfer in phase change materials (PCMs) [PDF]
, 2011 Heat transfer enhancement mechanism of Phase Change Materials (PCMs) by high-porosity metal foams was investigated in this study. The Darcy-Brinkman-Forchheimer modified flow model was employed in the numerical simulations to consider the non-Darcy ...
Tian, Y. (Yuan), Zhao, Changying
core
Interface Issues of Inorganic Solid‐State Electrolytes in Secondary Magnesium Batteries
Rare Metals, EarlyView.ABSTRACT Solid‐state magnesium batteries (SSMBs) have gained significant attention as promising candidates for next‐generation safe energy storage systems because of the abundance of magnesium (Mg) in the earth's crust, superior energy density, and inherent nonflammability.
Jiren Wang +9 more
wiley +1 more source
Flexibility of connection impact the power of heterogeneous FPGA(连接复杂度对非对称FPGA功耗的影响)
Zhejiang Daxue xuebao. Lixue ban, 2010 FPGA因为开发周期短、使用灵活、价格低廉等优点,在嵌入式系统中被广泛应用.随着开发需求的扩大,嵌入有DSP、MCU等宏模块的非对称FPGA应运而生.本文根据非对称FPGA的结构,研究连接复杂度Fc参数对功耗的影响.在不同Fc参数的非对称FPGA结构下对MCNC电路仿真,实验结果表明输入Fc参数在80%,输出Fc参数在70%时,其功耗最低.与Fc参数100%相比,输入Fc参数在80%时,平均功耗减少25.76%,最高功耗减少29.08%;输出Fc参数在70%时,平均功耗减少27.07%,最高功耗减少43.
XUKe-jun(徐科君) +1 more
doaj +1 more source
Dizhen xuebao, 2018 以SMART-1台阵第45号地震的南北分量加速度作为研究对象，计算截止频率fcut分别为8，16和24 Hz，台站间距分别为200，1 000和2 000 m这9种工况的相干系数，并进行曲线拟合，再根据9组拟合参数计算相应的相干系数并进行比较。结果表明：① 截止频率fcut的取值对相干函数统计模型参数和相干系数拟合曲线有很大影响；② 根据较小的截止频率fcut得到的拟合参数计算出的相干系数随频率的衰减很快，反之，根据较大的截止频率fcut得到的拟合参数计算出的相干系数随频率的衰减较慢；③ ...
Haiping Ding, Yi Luo, Weibo Rao, Yue Zhu
doaj +1 more source