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基于前向空间线性预测的声源时延估计算法 被引量:2
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作者 徐耀松 李猛 《计算机工程》 CAS CSCD 北大核心 2017年第6期259-263,共5页
在带有混响和噪音的复杂环境中,传统广义互相关时延估计算法的抗噪能力弱、时延估计精度低。为解决该问题,基于前向空间线性预测技术,提出一种时延估计算法。结合多传感器提供的冗余信息与空间相关矩阵,改进不利声学环境下的声达时间差... 在带有混响和噪音的复杂环境中,传统广义互相关时延估计算法的抗噪能力弱、时延估计精度低。为解决该问题,基于前向空间线性预测技术,提出一种时延估计算法。结合多传感器提供的冗余信息与空间相关矩阵,改进不利声学环境下的声达时间差估计方法。采用空-时预测法,根据麦克风阵列输出中包含的语音信号源的空间和时间相关性,在抑制多麦克风噪声的同时最小化语音失真。仿真实验结果表明,与传统广义互相关时延估计算法相比,该算法时延估计错误率更低、稳定性更强。 展开更多
关键词 声源定位 延估计 噪声抑制 空-时预测 前向间线性预测 间相关矩阵
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基于图神经网络的多光伏场站出力短期时-空预测
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作者 刘洪波 王铎皓 +3 位作者 石鹏 李倩倩 王曦 孙黎 《电网与清洁能源》 2025年第1期89-96,共8页
随着可再生能源的快速发展,光伏场站作为重要的电力供应来源之一,其出力短期时-空预测成为电力系统调度和运营的关键问题。提出了一种基于图神经网络的多光伏场站出力短期时-空预测方法,旨在解决以往研究对多光伏场站间光伏出力的时-空... 随着可再生能源的快速发展,光伏场站作为重要的电力供应来源之一,其出力短期时-空预测成为电力系统调度和运营的关键问题。提出了一种基于图神经网络的多光伏场站出力短期时-空预测方法,旨在解决以往研究对多光伏场站间光伏出力的时-空关联难以进行精准建模进而导致预测效果不精确的问题。首先,通过相关性分析方法确定影响光伏出力的核心特征,并构建特征集合。然后,充分考虑光伏场站光伏出力的时域和空域特征对预测效果的影响,将多个光伏场站数据以时-空图的形式进行表达,并通过边特征描述站点之间的关联程度。其次,利用图卷积层对时-空图数据进行学习,有效地捕捉时空图内节点之间的空间特征。最后,将图卷积层输出的空间特征构成时间序列输入至门控循环单元中,完成对时域特征的挖掘。与传统的预测方法相比,新方法有显著的优势。该方法能够充分考虑光伏场站之间的时空关联,提高了预测的准确性和可靠性。 展开更多
关键词 多光伏场站出力-预测 图卷积神经网络 图数据
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A study on the temporal and spatial characteristics of droughts following earthquakes
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作者 张凯 汤懋苍 高晓清 《Applied Geophysics》 SCIE CSCD 2013年第4期488-495,513,共9页
According to the "jacking-up" theory, which relates the cause of earthquakes to outer core convection ascension bodies, the crust will gradually recover after an earthquake. In such cases, the crust is stretched, th... According to the "jacking-up" theory, which relates the cause of earthquakes to outer core convection ascension bodies, the crust will gradually recover after an earthquake. In such cases, the crust is stretched, the underground temperature is reduced, precipitation decreases, and drought occurs. In this paper, precipitation is compared with ground temperature and seismic data to determine the spatial and temporal relationship between earthquakes and subsequent droughts. Our objective is to develop a new method of drought prediction. With a few exceptions in location, the analysis of the first drought to occur after the Ms 〉 7 earthquakes in China's Mainland and the adjacent areas since 1950 shows that droughts tended to occur in regions near earthquake epicenters and in the eastern regions of the epicenters at the same latitude within six months after the earthquakes. In addition, and the differences between the starting time of the earthquakes and the droughts nearly share the same probability of 0 to 6 months. After careful analysis of 34 Ms 〉 6.5 earthquakes occurring in western China from 1980 to 2011, we determined that a second drought tends to occur approximately six months following the first drought, indicating a quasi-half-year period. Moreover, the duration of the quasi-half-year fluctuation increases with the magnitude of earthquake, at approximately 2.5 years for Ms 6.5 earthquake and approximately 5 years for Ms 8 earthquake. 展开更多
关键词 EARTHQUAKE crust recovery quasi-half-year period epicenter drought area side drought area
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A Unified Spatio-Temporal Framework of the Cuerno-Barabasi Stochastic Continuum Model of Surface Sputtering
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作者 Oluwole Emmanuel Oyewande 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第7期165-170,共6页
The nonlinear continuum model proposed by Cuerno and Barabasi is the most successful and widely acceptable theoretical description of oblique incidence ion sputtered surfaces to date and is quite robust in its predict... The nonlinear continuum model proposed by Cuerno and Barabasi is the most successful and widely acceptable theoretical description of oblique incidence ion sputtered surfaces to date and is quite robust in its predictions of the time evolution and scaling of interfaces driven by ion bombardment. However, this theory has thus far predicted only ripple topographies and rough surfaces for short and large scales, respectively. As a result, its application to the interpretation and study of nanodots, predicted by Monte Carlo simulations for, and observed in experiments of, oblique incidence sputtering is still unclear and, hence, an open problem. In this paper, we provide a new insight to the theory, within the same length scale, that explains nanodot formation on off-normal incidence sputtered surfaces, among others, and propose ways of observing the predicted topographies of the MC simulations, as well as possible control of the size of the nanodots, in the framework of the Cuerno-Barabasi continuum theory. 展开更多
关键词 topographic phase diagrams surface nanostructures surface nanodots Cuerno-Barabasi model
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