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Online Wavelet Denoising via a Moving Window 被引量:15
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作者 XIA Rui MENG Ke +1 位作者 QIAN Feng WANG Zhen-Lei 《自动化学报》 EI CSCD 北大核心 2007年第9期897-901,共5页
In this paper,shortcoming of traditional wavelet denoising in real-time signal processing is discussed,requirements of online denoising are considered,and a moving window is introduced into traditional wavelet transfo... In this paper,shortcoming of traditional wavelet denoising in real-time signal processing is discussed,requirements of online denoising are considered,and a moving window is introduced into traditional wavelet transform.Using the moving window,an online wavelet denoising approach is proposed.Some problems of online denoising,such as border distortion and pseudo-Gibbs phenomena,are discussed.To solve these problems,window extension and window cycle spinning are also proposed.Different approaches are tested by the signal widely used in denoising domain.Both the visual results and the quantitative measures are presented to highlight the availability of the new approach. 展开更多
关键词 Discrete wavelet transform online denoising moving window window extension window circle spinning
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On-line Fault Diagnosis in Industrial Processes Using Variable Moving Window and Hidden Markov Model 被引量:9
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作者 周韶园 谢磊 王树青 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2005年第3期388-395,共8页
An integrated framework is presented to represent and classify process data for on-line identifying abnormal operating conditions. It is based on pattern recognition principles and consists of a feature extraction ste... An integrated framework is presented to represent and classify process data for on-line identifying abnormal operating conditions. It is based on pattern recognition principles and consists of a feature extraction step, by which wavelet transform and principal component analysis are used to capture the inherent characteristics from process measurements, followed by a similarity assessment step using hidden Markov model (HMM) for pattern comparison. In most previous cases, a fixed-length moving window was employed to track dynamic data, and often failed to capture enough information for each fault and sometimes even deteriorated the diagnostic performance. A variable moving window, the length of which is modified with time, is introduced in this paper and case studies on the Tennessee Eastman process illustrate the potential of the proposed method. 展开更多
关键词 wavelet transform principal component analysis hidden Markov model variable moving window fault diagnosis
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Double Moving Window MPCA for Online Adaptive Batch Monitoring 被引量:5
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作者 赵立杰 柴天佑 王纲 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2005年第5期649-655,共7页
Online monitoring of chemical process performance is extremely important to ensure the safety of a chemical plant and consistently high quality of products. Multivariate statistical process control has found wide appl... Online monitoring of chemical process performance is extremely important to ensure the safety of a chemical plant and consistently high quality of products. Multivariate statistical process control has found wide applications in process performance analysis, monitoring and fault diagnosis using existing rich historical database.In this paper, we propose a simple and straight forward multivariate statistical modeling based on a moving window MPCA (multiway principal component analysis) model along the time and batch axis for adaptive monitoring the progress of batch processes in real-time. It is an extension to minimum window MPCA and traditional MPCA.The moving window MPCA along the batch axis can copy seamlessly with variable run length and does not need to estimate any deviations of the ongoing batch from the average trajectories. It replaces an invariant fixed-model monitoring approach with adaptive updating model data structure within batch-to-batch, which overcomes the changing operation condition and slows time-varying behaviors of industrial processes. The software based on moving window MPCA has been successfully applied to the industrial polymerization reactor of polyvinyl chloride (PVC) process in the Jinxi Chemical Company of China since 1999. 展开更多
关键词 moving window multiway principal component analysis batch monitoring
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Land use induced blurring of forest-grassland transition in north-west Himalaya-A case study using Moving Split Window boundary detection technique 被引量:1
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作者 Shevita PANDITA Harish Chander DUTT 《Journal of Mountain Science》 SCIE CSCD 2020年第12期3085-3096,共12页
Transition zone or ecotone is a unique community sandwiched between two communities/ecosystems/biomes.These ecotones in Himalaya remained unexplored for many ecological aspects like biodiversity,phyto-sociology,bounda... Transition zone or ecotone is a unique community sandwiched between two communities/ecosystems/biomes.These ecotones in Himalaya remained unexplored for many ecological aspects like biodiversity,phyto-sociology,boundary detection and even impact of change in land use pattern(anthropogenic activity).The most accepted and widespread technique called as Moving Split Window(MSW) technique is used for detection of vegetation and environmental boundaries at four different sites in the lesser stratum of north-west Himalaya.All the four sites were at different distances from the nearest human inhabited area.Anthropogenic activities like grazing,herb collection,wood collection etc.were common at proximal sites.Such activities have led to the change in land use pattern.In this study,we have tried to work out the impact of the change in land use pattern(human interference) on the vegetation and basic environmental parameters like soil pH,electrical conductivity and moisture on forestgrassland ecotone in north-west Himalaya.Data on mountain steepness was also collected and analyzed.The dissimilarity profile using the statistical tool Squared Euclidian Distance(SED) indicated that species turnover locations increase with the increase in distance of ecotones from human settlements.The ecotones at distant locations from human villages are characterized with blunt as well as sharp peaks for vegetation data,however,conditions are reverse in case of the proximal sites.The study also reveals that as the distance between the ecotone and human settlements increases,the complex conditions like multiple vegetation boundaries prevails on the transitions.In this regard,land use induced blurring of forest-grassland transition in north-west Himalaya is summed up in the study. 展开更多
关键词 ECOTONE moving Split window Squared Euclidean Distance TRANSECT Dissimilarity function Environment variables
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Analysis of Landscape Patterns in the Urban-Rural Integrated Area Based on Moving Window: A Case Study of Sanshui District in Foshan City 被引量:1
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作者 CAO Xiaoshu LIU Yongwei LI Tao 《Journal of Landscape Research》 2018年第2期24-30,41,共8页
The urban-rural integrated area in Sanshui District of Foshan City was selected for research, and the impact of landscape pattern around the No.269 provincial highway was analyzed based on the land-use data in 2014 us... The urban-rural integrated area in Sanshui District of Foshan City was selected for research, and the impact of landscape pattern around the No.269 provincial highway was analyzed based on the land-use data in 2014 using the spatial analysis in GIS and the moving window method. The results showed that:(1) within the scope of a 2 km-range buffer zone, with a low degree of heterogeneity, land for construction use and water area were the dominant land-use types, while with a high degree of fragmentation, cultivated land, wooded land, grassland, garden land, land for other farm uses, and land unused were scattered;(2) the 250-m square moving window could well detect the change characteristics of landscape pattern on both sides of the road;(3) the gradient analysis of landscape pattern in urban-rural integrated area, which was conducted with the aid of a 750-m transect on both sides of the road, indicated that there were significant differences between landscape indexes both in the urban-rural integrated area and on both sides of the road;(4) the road that had an obvious cutting and fragmentation impact on the landscape was an important factor leading to the increasing fragmentation and heterogeneity to regional landscapes. 展开更多
关键词 Urban-rural integration Urban-rural gradient analysis Landscape pattern moving window
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Discriminant Analysis of Liquor Brands Based on Moving-Window Waveband Screening Using Near-Infrared Spectroscopy 被引量:6
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作者 Jie Zhong Jiemei Chen +1 位作者 Lijun Yao Tao Pan 《American Journal of Analytical Chemistry》 2018年第3期124-133,共10页
Partial least squares discriminant analysis (PLS-DA) with integrated moving-window (MW) waveband screening was applied to the discriminant analysis of liquor brands with near-infrared (NIR) spectroscopy. Luzhou Laojia... Partial least squares discriminant analysis (PLS-DA) with integrated moving-window (MW) waveband screening was applied to the discriminant analysis of liquor brands with near-infrared (NIR) spectroscopy. Luzhou Laojiao, a popular liquor with strong fragrant flavor, was used as the identified liquor brand (160 samples, negative, 52 vol alcoholicity). Liquors of 10 other brands with strong fragrant flavor were used as the interferential brands (200 samples, positive, 52 vol alcoholicity). The Kennard-Stone algorithm was used for the division of modeling samples to achieve uniformity and representativeness. Based on the MW-PLS-DA, a simplified optimal model set with 157 wavebands was further proposed. This set contained five types of wavebands corresponding to the NIR absorption bands of water, ethanol, and other micronutrients (i.e., acids, aldehydes, phenols, and aromatic compounds) in liquor for practical choice. Using five selected simple models with 4775 - 4239, 7804 - 6569, 6264 - 5844, 9435 - 7896, and 12066 - 10373 cm-1, the validation recognition rates were obtained as 99.3% or higher. Results show good prediction performance and low model complexity, and also provided a valuable reference for designing small dedicated instruments. The proposed method is a promising tool for large-scale inspection of liquor food safety. 展开更多
关键词 LIQUOR Brands NEAR-INFRARED Spectroscopy PARTIAL Least SQUARES DISCRIMINANT Analysis moving-window Waveband SCREENING Simplified Optimal Model Set
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High-Dimensional Regression on Sparse Grids Applied to Pricing Moving Window Asian Options
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作者 Stefan Dirnstorfer Andreas J. Grau Rudi Zagst 《Open Journal of Statistics》 2013年第6期427-440,共14页
The pricing of moving window Asian option with an early exercise feature is considered a challenging problem in option pricing. The computational challenge lies in the unknown optimal exercise strategy and in the high... The pricing of moving window Asian option with an early exercise feature is considered a challenging problem in option pricing. The computational challenge lies in the unknown optimal exercise strategy and in the high dimensionality required for approximating the early exercise boundary. We use sparse grid basis functions in the Least Squares Monte Carlo approach to solve this “curse of dimensionality” problem. The resulting algorithm provides a general and convergent method for pricing moving window Asian options. The sparse grid technique presented in this paper can be generalized to pricing other high-dimensional, early-exercisable derivatives. 展开更多
关键词 Sparse Grid Regression LEAST-SQUARES Monte Carlo moving window Asian OPTION
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State Estimation Moving Window Gradient Iterative Algorithm for Bilinear Systems Using the Continuous Mixed p-norm Technique
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作者 Wentao Liu Junxia Ma Weili Xiong 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第2期873-892,共20页
This paper studies the parameter estimation problems of the nonlinear systems described by the bilinear state space models in the presence of disturbances.A bilinear state observer is designed for deriving identificat... This paper studies the parameter estimation problems of the nonlinear systems described by the bilinear state space models in the presence of disturbances.A bilinear state observer is designed for deriving identification algorithms to estimate the state variables using the input-output data.Based on the bilinear state observer,a novel gradient iterative algorithm is derived for estimating the parameters of the bilinear systems by means of the continuous mixed p-norm cost function.The gain at each iterative step adapts to the data quality so that the algorithm has good robustness to the noise disturbance.Furthermore,to improve the performance of the proposed algorithm,a dynamicmoving window is designed which can update the dynamical data by removing the oldest data and adding the newestmeasurement data.A numerical example of identification of bilinear systems is presented to validate the theoretical analysis. 展开更多
关键词 Bilinear state space model parameter estimation moving window continuous mixed p-norm
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基于半抑制式模糊C均值和区域增长的建筑物点云提取算法
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作者 蔡湛 马洪超 +1 位作者 姚春静 许小龙 《测绘工程》 2026年第1期27-33,共7页
城市三维建模的核心要素在于建筑物的精准表达,随着智慧城市建设的推进,高精度建筑模型的需求呈现指数级增长。文中聚焦机载LiDAR技术这一新型主动遥感手段,其通过发射激光脉冲可直接获取亚米级精度的三维地物点云,为城市数字化建设提... 城市三维建模的核心要素在于建筑物的精准表达,随着智慧城市建设的推进,高精度建筑模型的需求呈现指数级增长。文中聚焦机载LiDAR技术这一新型主动遥感手段,其通过发射激光脉冲可直接获取亚米级精度的三维地物点云,为城市数字化建设提供全新的数据源。针对建筑物三维重建中涉及的滤波、建筑物提取等关键技术问题,开展以下创新性工作:首先,提出融合动态窗口与渐进式区域生长的混合滤波算法,通过引入自适应高差阈值机制,有效解决了传统方法在陡坎等地形突变区域的误分类问题,实验表明该算法在平坦城区的地面点识别准确率略有提升。最后,创新性地将半抑制式模糊聚类与多约束区域生长相结合,通过构建特征空间(含高程方差、λ2特征值、平面性等三维描述因子),实现了建筑内部结构特征与外部轮廓信息的协同挖掘。与现有方法相比,文中算法提取建筑物的完整率和提取质量稍占优势。 展开更多
关键词 机载激光雷达 半抑制式模糊聚类 滤波 移动窗口法 区域增长
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低卫星高度角情况下的周跳探测算法研究
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作者 邢云剑 陈向东 +1 位作者 姜蔚 李开元 《测绘与空间地理信息》 2026年第3期127-130,137,共5页
针对TurboEdit算法在卫星高度角较低时周跳探测性能不佳的问题,提出了正反向窗口平滑滤波和相位电离层残差组合二阶历元间差分结合的周跳探测算法的一组周跳阈值判定条件。通过处理CHAN测站的8颗卫星1 d的数据,对比不同周跳探测算法的... 针对TurboEdit算法在卫星高度角较低时周跳探测性能不佳的问题,提出了正反向窗口平滑滤波和相位电离层残差组合二阶历元间差分结合的周跳探测算法的一组周跳阈值判定条件。通过处理CHAN测站的8颗卫星1 d的数据,对比不同周跳探测算法的探测结果。结果表明,采用正反向窗口平滑滤波和相位电离层残差组合二阶历元间差分结合的周跳探测算法相比于TurboEdit算法的探测能力更优,有效地减少了误检、漏检的现象。 展开更多
关键词 周跳 无几何组合 Melbourne-Wubeena组合 正反向移动窗口平滑 相位电离层残差组合二次历元间差分
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Variance Window Based Car License Plate Localization 被引量:1
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作者 Jing Pang 《Journal of Computer and Communications》 2014年第9期61-69,共9页
In this paper, a new method for discovering the candidate car license plate locations is presented. First, the image is decomposed using a Haar wavelet to get the HL band with vertical edges. Then, the HL band image i... In this paper, a new method for discovering the candidate car license plate locations is presented. First, the image is decomposed using a Haar wavelet to get the HL band with vertical edges. Then, the HL band image is binarized using an Otsu threshold. Next a black top-hat algorithm is applied to reduce the effects of interfering large continuous features other than the license plate. At this time, a moving window based modified variance score calculation is made for areas with white pixels. This work found that the top 3 detected rectangle windows correctly locate the license plate regions with a success rate of about 98.2%. Moreover, the proposed method is robust enough to locate the plates in cases where the rough vehicle position has not been previously discovered and the cars are not centered in the image. 展开更多
关键词 Harr WAVELET BLACK TOP-HAT BINARIZATION moving window Variance SCORE
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让window7跑的更快 丢掉肥肉快速瘦身
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作者 王雷 《计算机与网络》 2014年第13期34-34,共1页
不知道大家有没有注意过,在Vista和Windows 7系统盘的Windows目录下,都同时有一个名为winsxs的文件夹,对于整个Windows文件夹目录来说,这个文件夹就占用了其一半多的大小体积(近3GB)不仅如此,随着系统使用时间的不断延长,winsxs文件夹... 不知道大家有没有注意过,在Vista和Windows 7系统盘的Windows目录下,都同时有一个名为winsxs的文件夹,对于整个Windows文件夹目录来说,这个文件夹就占用了其一半多的大小体积(近3GB)不仅如此,随着系统使用时间的不断延长,winsxs文件夹的体积大小还会变得更大,我的现在已经4G多了,这可真是一块有油水的肥肉啊!想想看吧!对于系统盘空间本来就不很富裕的朋友来说,这快肥肉是肯定会拖慢系统的运行速度。如果仅仅是因为这个原因。 展开更多
关键词 系统盘 可真 运行速度 window7 硬盘分区 复制文件 moved 重装系统 压缩包 内容复制
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基于MW-FDTD与树木精细模型的树林电波传播研究 被引量:3
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作者 刘健明 陈鹏 +2 位作者 杨永钦 苏婷 迟阔 《电波科学学报》 北大核心 2025年第3期559-566,共8页
随着城市低空经济的提出和发展,对城市无线通信信道精细化建模仿真提出了更高的要求。特别是在无人机等应用场景中,城市树林环境对电波传播的影响不可忽略。本文首先提出了树木精细建模方法,相较于传统的树木近似建模方法,所提方法能够... 随着城市低空经济的提出和发展,对城市无线通信信道精细化建模仿真提出了更高的要求。特别是在无人机等应用场景中,城市树林环境对电波传播的影响不可忽略。本文首先提出了树木精细建模方法,相较于传统的树木近似建模方法,所提方法能够更精确地描述树木特征;其次,引入向量化滑动窗时域有限差分(moving window finite-difference time-domain,MW-FDTD)方法,提高了树林电波传播问题的计算效率;最后,针对两类典型城市植被环境,进行了树林电波传播测量,并将测量数据与数值仿真结果进行了对比。数据对比结果表明,与传统MW-FDTD相比,向量化MW-FDTD具有更高的计算效率;与树木近似模型相比,树木精细模型的仿真结果与实测数据的均方根误差更小。 展开更多
关键词 传播模型 时域有限差分(FDTD)法 滑动窗 树木模型 电波传播特性
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移动窗口多普勒平滑伪距增强的GNSS/IMU/单目视觉紧组合定位 被引量:1
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作者 何进辛 高井祥 +1 位作者 潘诚 王永辉 《测绘通报》 北大核心 2025年第1期101-106,共6页
本文针对在多源融合导航系统中GNSS伪距观测值受环境影响较大使得定位精度下降的问题,提出了基于移动窗口的多普勒平滑伪距算法。首先建立基于因子图优化的GNSS/IMU/单目视觉紧组合导航系统模型,然后使用开源数据集验证算法的有效性并... 本文针对在多源融合导航系统中GNSS伪距观测值受环境影响较大使得定位精度下降的问题,提出了基于移动窗口的多普勒平滑伪距算法。首先建立基于因子图优化的GNSS/IMU/单目视觉紧组合导航系统模型,然后使用开源数据集验证算法的有效性并与常规加权多普勒平滑伪距算法进行对比。结果表明,该算法在伪距定位中E、N和U 3个方向上定位精度分别达到1.591、2.892和2.001 m,定位精度分别提升了50.7%、61.7%、56.8%;在多源融合导航定位系统中定位精度分别达到1.390、2.561和1.606 m,比未平滑前的定位精度3个方向上分别提高了9.8%、20.0%和11.1%;同时该结果与常规加权多普勒平滑相比,定位精度分别提升了4.7%、3.1%、0.5%。 展开更多
关键词 多源融合导航 因子图 伪距 移动窗口 多普勒平滑
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基于MS-MWKECA自适应工业过程故障检测 被引量:1
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作者 李晓瑞 刘建昌 郭青秀 《控制与决策》 北大核心 2025年第12期3587-3596,共10页
针对过程数据具有变量非线性耦合、过程尺度多样等特征,提出一种基于多尺度滑动窗口核熵成分分析(MS-MWKECA)自适应工业过程故障检测方法.首先,使用小波变换将过程变量实时地分解成不同的细节尺度和近似尺度,建立基于熵成分分析(KECA)... 针对过程数据具有变量非线性耦合、过程尺度多样等特征,提出一种基于多尺度滑动窗口核熵成分分析(MS-MWKECA)自适应工业过程故障检测方法.首先,使用小波变换将过程变量实时地分解成不同的细节尺度和近似尺度,建立基于熵成分分析(KECA)的局部尺度模型,并筛选具有显著特征的尺度用于数据重构;随后,对重构的数据建立基于滑动窗口KECA的在线检测模型,并且在滑动窗口更新数据的过程中,设计一种自适应权重分配的窗口更新融合策略;最后,在Tennessee-Eastman(TE)过程和热轧生产过程(HSMP)中进行仿真测试,通过对比实验验证所提方法的有效性和优越性. 展开更多
关键词 多尺度 核熵成分分析 自适应权重分配 滑动窗口 故障检测
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2~5年级小学生汉语阅读知觉广度的发展轨迹
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作者 李赛男 王亚丽 +3 位作者 袁小源 刘妮娜 赵淑萍 闫国利 《心理发展与教育》 北大核心 2025年第3期305-312,共8页
阅读知觉广度是指读者在一次注视时能够获得有效信息的范围。以往研究中,系统探讨不同年级小学生汉语阅读知觉广度的实验尚不多见。本研究使用移动窗口技术,探讨小学2~5年级学生阅读知觉广度的发展轨迹。通过要求所有被试阅读一般通用材... 阅读知觉广度是指读者在一次注视时能够获得有效信息的范围。以往研究中,系统探讨不同年级小学生汉语阅读知觉广度的实验尚不多见。本研究使用移动窗口技术,探讨小学2~5年级学生阅读知觉广度的发展轨迹。通过要求所有被试阅读一般通用材料(即二年级水平材料)以及与年龄相匹配的材料,考察不同年级学生的阅读知觉广度。结果发现当所有年级均阅读一般通用材料时,二年级的阅读广度为注视点右侧2个汉字,三到五年级为3个汉字;当阅读年龄匹配材料时,所有年级的阅读知觉广度均为右侧2个汉字。本研究结果说明,材料难度调节小学生的阅读知觉广度。本研究为构建汉语儿童阅读的眼动模型提供了数据支持,同时对于指导小学语文阅读教学具有一定的参考价值。 展开更多
关键词 小学生 阅读发展 知觉广度 移动窗口范式
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滑动窗口分位数映射的净初级生产力空间降尺度方法
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作者 秦云 於琍 +2 位作者 李晓东 程春香 刘秋锋 《地球信息科学学报》 北大核心 2025年第8期1883-1895,共13页
【目的】净初级生产力(NPP)是评估陆地生态系统碳汇的一个关键指标,在全球和区域尺度研究上通常采用生态模型对其进行估算。遥感估算模型虽然准确度较高,但在对未来NPP的预估以及长期生态气候响应研究方面受到了限制;过程机理模型弥补... 【目的】净初级生产力(NPP)是评估陆地生态系统碳汇的一个关键指标,在全球和区域尺度研究上通常采用生态模型对其进行估算。遥感估算模型虽然准确度较高,但在对未来NPP的预估以及长期生态气候响应研究方面受到了限制;过程机理模型弥补了遥感估算模型的上述缺陷,但空间分辨率相对较低。【方法】本文提出了一种滑动窗口分位数映射方法,利用遥感估算模型(CASA)获取的细分辨率植被NPP的纹理特征,对生态机理模型(CEVSA)模拟的粗分辨率NPP进行空间降尺度研究。通过提取2001—2010年CASA-NPP的纹理特征对CEVSA-NPP进行调整后,通过设置一个滑动的窗口,在较小的空间范围内,采用分位数映射法对调整后的CEVSA-NPP进行订正,最后利用2011—2019年的数据对结果进行检验。【结果】以青海省为案例研究区的结果显示,与CEVSA-NPP和CASA-NPP二者之间的偏差相比,降尺度后的NPP值与CASA-NPP更为接近,均方根误差(RMSE)降低了57%,基本保留了CEVSA-NPP原有的变化趋势方向和年际变化特征;农田生态系统和聚落生态系统的RMSE最大,其次是森林生态系统,荒漠生态系统、草地生态系统以及水体与湿地生态系统的RMSE相对较小。【结论】该降尺度方法可用于对过程机理模型模拟结果以及未来预测预估结果分辨率的提升,为开展精细化的区域生态系统碳收支影响评估及极端气候事件对生态系统的影响评估等提供数据和方法支持。 展开更多
关键词 降尺度 净初级生产力 分位数映射 CEVSA模型 CASA模型 滑动窗口 中心差分
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结合移动窗的多因子噪声修正响应重构
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作者 车佳亮 彭珍瑞 《机械科学与技术》 北大核心 2025年第11期1868-1875,共8页
为改善移动窗法估计测量噪声方差时由于权值选取的不确定所导致的测量噪声偏差引起响应重构精度的降低、甚至滤波发散问题,提出了一种结合移动窗的多因子噪声修正卡尔曼滤波(Correction moving-window Kalman filter,CMWKF)结构响应重... 为改善移动窗法估计测量噪声方差时由于权值选取的不确定所导致的测量噪声偏差引起响应重构精度的降低、甚至滤波发散问题,提出了一种结合移动窗的多因子噪声修正卡尔曼滤波(Correction moving-window Kalman filter,CMWKF)结构响应重构方法。首先选取任意经验权值,用改进移动窗法进行噪声方差估计,设计多个修正因子对估计的测量噪声方差进行修正,最后基于卡尔曼滤波算法,使用有限测点的响应重构结构未测量处的响应。通过二维起重机桁架和悬臂梁结构验证所提方法的有效性,结果表明该方法能够较好地改善移动窗噪声方差估计所带来的权值影响,有效重构结构未测点处的响应时程曲线。 展开更多
关键词 移动窗 噪声修正 卡尔曼滤波 响应重构
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浅海中Scholte波的Airy相研究
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作者 罗夏云 陈新宁 刘宝 《兵工学报》 北大核心 2025年第8期397-406,共10页
为研究Scholte波Airy相的形成机理,理清其特征及变化规律,基于浅海半无限弹性海底声场模型,推导求解脉冲声源激发Scholte波的波场表达式。利用高阶交错网格有限差分算法对脉冲声源激发Scholte波进行数值仿真,得到Airy波幅值与传播距离... 为研究Scholte波Airy相的形成机理,理清其特征及变化规律,基于浅海半无限弹性海底声场模型,推导求解脉冲声源激发Scholte波的波场表达式。利用高阶交错网格有限差分算法对脉冲声源激发Scholte波进行数值仿真,得到Airy波幅值与传播距离之间的关系。理论研究结果表明:Scholte波因频散会使其群速度出现一个极小值,导致脉冲信号在传播过程中出现Airy波,其振幅与r^(-5/6)(r为传播距离)呈正比。开展湖上气枪声源激发Scholte波试验,利用滑动窗分析法对试验数据展开分析。试验结果表明:12 Hz以下频段明显存在频散现象,频率高于12 Hz后,随着频率的增加群速度基本保持不变,同时群速度随频率的增加呈先减小后增大的变化规律,再现并印证了理论研究中Scholte波群速度的频散关系。 展开更多
关键词 Scholte波 Airy相 频散特性 滑动窗 群速度
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丹霞地貌发育程度的定量指示及影响因素:以广东丹霞山为例 被引量:1
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作者 傅强 章桂芳 +2 位作者 张珂 王同皓 叶雨朦 《地球科学》 北大核心 2025年第2期782-797,共16页
地貌发育的定量化研究对于深化丹霞地貌的基础研究和多学科融合具有重要意义,而地貌指数可以用于评估区域构造活动及地貌演化,定量指示地貌发育程度,有助于理解丹霞地貌的发育过程及控制因素.因此,以广东丹霞山世界地质公园为研究区,基... 地貌发育的定量化研究对于深化丹霞地貌的基础研究和多学科融合具有重要意义,而地貌指数可以用于评估区域构造活动及地貌演化,定量指示地貌发育程度,有助于理解丹霞地貌的发育过程及控制因素.因此,以广东丹霞山世界地质公园为研究区,基于TecDEM工具箱移动窗口方法选择窗口大小并计算面积高程积分(HI)、地表粗糙度(SR)和地表指数(SI)这3种地貌指数.丹霞山移动窗口边长可选择900 m,由此计算的丹霞组HI集中于0.22~0.47,SR和SI分别集中在1.05~1.14和−0.37~−0.11,SR和SI呈显著的负相关,且高SR和低SI多在赤壁丹崖景观一带分布,表明丹霞山的地貌发育程度整体较高,与学者定义的丹霞山地貌发育阶段相符.分析地貌指数与断裂、地层和河流的定量关系可知:HI值及SR值随着与断裂两侧距离的增大而逐渐下降;锦石岩段的HI值集中于0.29~0.48,在丹霞组中最高,巴寨段及白寨顶段较低;河流两侧的白寨顶段显示出较高的HI值(>0.24),而巴寨段具有较低的HI值,显示其在构造分布和河流的共同作用下呈现较明显的侧蚀. 展开更多
关键词 丹霞地貌 TecDEM工具箱 移动窗口 地貌指数 定量研究 地貌学
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