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Ultrahigh spatiotemporal resolution beam signal reconstruction with bunch phase compensation
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作者 You-Ming Deng Yong-Bin Leng +2 位作者 Xing-Yi Xu Jian Chen Yi-Mei Zhou 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第5期99-108,共10页
Various electromagnetic signals are excited by the beam in the acceleration and beam-diagnostic elements of a particle accelerator.It is important to obtain time-domain waveforms of these signals with high temporal re... Various electromagnetic signals are excited by the beam in the acceleration and beam-diagnostic elements of a particle accelerator.It is important to obtain time-domain waveforms of these signals with high temporal resolution for research,such as the study of beam–cavity interactions and bunch-by-bunch parameter measurements.Therefore,a signal reconstruction algorithm with ultrahigh spatiotemporal resolution and bunch phase compensation based on equivalent sampling is proposed in this paper.Compared with traditional equivalent sampling,the use of phase compensation and setting the bunch signal zero-crossing point as the time reference can construct a more accurate reconstructed signal.The basic principles of the method,simulation,and experimental comparison are also introduced.Based on the beam test platform of the Shanghai Synchrotron Radiation Facility(SSRF)and the method of experimental verification,the factors that affect the reconstructed signal quality are analyzed and discussed,including the depth of the sampled data,quantization noise of analog-to-digital converter,beam transverse oscillation,and longitudinal oscillation.The results of the beam experiments show that under the user operation conditions of the SSRF,a beam excitation signal with an amplitude uncertainty of 2%can be reconstructed. 展开更多
关键词 Turn-by-turn bunch phase compensation technique Equivalent sampling Signal reconstruction algorithm Ultrahigh spatiotemporal resolution SSRF
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Iterative Learning Fault Diagnosis Algorithm for Non-uniform Sampling Hybrid System 被引量:2
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作者 Hongfeng Tao Dapeng Chen Huizhong Yang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2017年第3期534-542,共9页
For a class of non-uniform output sampling hybrid system with actuator faults and bounded disturbances,an iterative learning fault diagnosis algorithm is proposed.Firstly,in order to measure the impact of fault on sys... For a class of non-uniform output sampling hybrid system with actuator faults and bounded disturbances,an iterative learning fault diagnosis algorithm is proposed.Firstly,in order to measure the impact of fault on system between every consecutive output sampling instants,the actual fault function is transformed to obtain an equivalent fault model by using the integral mean value theorem,then the non-uniform sampling hybrid system is converted to continuous systems with timevarying delay based on the output delay method.Afterwards,an observer-based fault diagnosis filter with virtual fault is designed to estimate the equivalent fault,and the iterative learning regulation algorithm is chosen to update the virtual fault repeatedly to make it approximate the actual equivalent fault after some iterative learning trials,so the algorithm can detect and estimate the system faults adaptively.Simulation results of an electro-mechanical control system model with different types of faults illustrate the feasibility and effectiveness of this algorithm. 展开更多
关键词 Equivalent fault model fault diagnosis iterative learning algorithm non-uniform sampling hybrid system virtual fault
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S/N Ratio of 4-Channel A/D Geological Radar Non-uniform Sampling Signals 被引量:2
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作者 MA Kai SU Hong-qi 《Journal of China University of Mining and Technology》 EI 2007年第4期534-536,共3页
Using the quantitative error probability density method we studied the S/N ratio of alternately sampled signals digitized by a 4-channel A/D. A complete expression for the S/N ratio of a 4-channel A/D non-uniform samp... Using the quantitative error probability density method we studied the S/N ratio of alternately sampled signals digitized by a 4-channel A/D. A complete expression for the S/N ratio of a 4-channel A/D non-uniform sampling signal was deduced. First we obtained an expression for the S/N ratio of a 1-channel A/D uniform sampling signal when the sampling frequency was equal to or greater than 2 times the frequency of the sampled signal. Based on the S/N ratio of a 2-channel A/D,alternating,non-uniform sampling signal,we analyzed the distribution of quantitative error using the quantitative error probability density method and the distribution convolution formula. From this the S/N ratio expression of a 4-channel A/D sampling signal was deduced. The simulation result shows that the deduced expression is correct. 展开更多
关键词 geological radar 4-channel non-uniform sampling sum distribution S/N ratio
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FAST ALGORITHM FOR NON-UNIFORMLY SAMPLED SIGNAL SPECTRUM RECONSTRUCTION
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作者 Zhu Zhenqian Zhang Zhimin Wang Yu 《Journal of Electronics(China)》 2013年第3期231-236,共6页
In this paper, a fast algorithm to reconstruct the spectrum of non-uniformly sampled signals is proposed. Compared with the original algorithm, the fast algorithm has a higher computational efficiency, especially when... In this paper, a fast algorithm to reconstruct the spectrum of non-uniformly sampled signals is proposed. Compared with the original algorithm, the fast algorithm has a higher computational efficiency, especially when sampling sequence is long. Particularly, a transformation matrix is built, and the reconstructed spectrum is perfectly synthesized from the spectrum of every sampling channel. The fast algorithm has solved efficiency issues of spectrum reconstruction algorithm, and making it possible for the actual application of spectrum reconstruction algorithm in multi-channel Synthetic Aperture Radar (SAR). 展开更多
关键词 Synthetic Aperture Radar (SAR) non-uniform sampling Multi-channel SAR Spectrum reconstruction High-resolution and wide-swath
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入侵意图分析下的软件定义网络DDoS攻击检测方法 被引量:2
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作者 徐涌霞 《成都工业学院学报》 2024年第1期64-68,81,共6页
为在数据样本回溯期内解决因本地信息熵值增大而造成的服务攻击问题,维护软件定义网络的运行安全性,提出入侵意图分析下的软件定义网络分布式拒绝服务(DDoS)攻击检测方法。按照软件定义网络场景重构原则,确定因果网转换标准,实现对识别... 为在数据样本回溯期内解决因本地信息熵值增大而造成的服务攻击问题,维护软件定义网络的运行安全性,提出入侵意图分析下的软件定义网络分布式拒绝服务(DDoS)攻击检测方法。按照软件定义网络场景重构原则,确定因果网转换标准,实现对识别参数的更新处理,完成攻击性行为的入侵意图分析,再定义DDoS数据集,根据攻击行为的时空特性,求解模型参数的取值范围,完成入侵意图分析下软件定义网络DDoS攻击检测方法的设计。实验结果表明,在该算法控制下数据样本回溯期为10 min,低于传统算法,能够较好维护软件定义网络的运行安全性。 展开更多
关键词 软件定义网络 DDOS攻击 样本回溯期 本地信息熵 时空特性
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基于时空扩散的输电走廊图像火灾预警方法
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作者 唐冬来 田富强 +4 位作者 何鹏 谷波 田攀 李军 阮正平 《电子技术应用》 2024年第10期51-56,共6页
为解决输电走廊图像火灾预警误报率高的问题,提出了一种基于时空扩散的输电走廊图像山火预警方法。首先,采用脉宽调制整流感应取电互感器方式实现摄像头取电。其次,对采集图像进行预处理,消除图像噪声对模型火灾识别带来的影响,并提取... 为解决输电走廊图像火灾预警误报率高的问题,提出了一种基于时空扩散的输电走廊图像山火预警方法。首先,采用脉宽调制整流感应取电互感器方式实现摄像头取电。其次,对采集图像进行预处理,消除图像噪声对模型火灾识别带来的影响,并提取输电走廊图像特征,建立正常样本库;在此基础上,通过正常样本比对,筛选出异常样本,并结合时空扩散方法分析烟雾时间维度的形态变化情况,进而识别火灾。最后,在某供电公司的实际应用中,该方法的火灾识别准确率为98.7%,所提方法能有效区分云彩和火灾烟雾特征,实现输电走廊穿越森林火灾的精准识别。 展开更多
关键词 时空扩散 输电走廊 图像 火灾预警 烟雾特征 正常样本库
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大气污染源排放时空分布特征及减排潜力分析 被引量:1
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作者 刘军民 李程 +3 位作者 黄小兰 蒙晓瑞 杜小称 张婷婷 《能源与环保》 2024年第6期174-178,184,共6页
在开展大气污染源时空分布特征研究时,如果不能及时获取目标城市的大气污染源类型,将直接降低对大气污染源时空分布特征的准确性。为此,提出了一种大气污染源排放时空分布特征及减排潜力分析方法。该方法首先确定研究对象,并进行区域概... 在开展大气污染源时空分布特征研究时,如果不能及时获取目标城市的大气污染源类型,将直接降低对大气污染源时空分布特征的准确性。为此,提出了一种大气污染源排放时空分布特征及减排潜力分析方法。该方法首先确定研究对象,并进行区域概况分析,以确定相关污染源类型,并设置监测点以收集污染数据。然后,利用这些数据获取该研究区域大气污染源的排放时空分布特征,并详细分析该研究对象的减排潜力,为后续城市大气污染治理工作提供有力依据。研究结果表明,在安阳市,大气污染源整体呈现出冬夏两季污染严重、春秋污染程度较轻的双峰状态。从空间分布来看,大气污染程度较为严重且分布较为分散。然而,这个城市具有巨大的减排潜力,可通过取缔工业锅炉、提升工业单位污染物净化设备效率等手段来实现减排。这些结果为制定有效的大气污染治理措施提供了重要依据。 展开更多
关键词 大气污染源排放 时空分布特征 减排潜力分析 污染源确定 采样点布设
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基于自校准机制的时空采样图卷积行为识别模型
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作者 曹毅 吴伟官 +2 位作者 张小勇 夏宇 高清源 《工程科学学报》 EI CSCD 北大核心 2024年第3期480-490,共11页
针对现有行为识别算法忽视时空信息上下文的依赖关系和缺乏多层次感受野的特征提取问题,本文提出一种基于自校准机制的时空采样图卷积网络行为识别模型.首先,介绍ST-GCN和3D-GCN、Transformer和自注意力机制的工作原理,并分析了3D-GCN和... 针对现有行为识别算法忽视时空信息上下文的依赖关系和缺乏多层次感受野的特征提取问题,本文提出一种基于自校准机制的时空采样图卷积网络行为识别模型.首先,介绍ST-GCN和3D-GCN、Transformer和自注意力机制的工作原理,并分析了3D-GCN和Transformer不能有效进行时空上下文建模;其次,为有效进行时空上下文建模而提出了一种时空采样图卷积网络,其以时序连续多帧作为时空采样将全局动作分为多个子动作,通过非局部网络计算单一节点与采样频率帧内所有节点的相关性来建立局部跨时空依赖关系,并通过结合非局部网络和时域卷积计算单个采样子动作与全局子动作的相关性以此来建立全局跨时空依赖关系;然后,为了有效地增强多层次的感受野来捕获更具判别力的时域特征,提出了一种时域自校准卷积网络在两个不同的尺度时空中分别进行卷积并特征融合:一种是原始比例尺度的时空,另一种是使用下采样具有较小比例尺度的潜在时空;再者,结合时空采样图卷积网络和时域自校准网络构建基于自校准机制的时空采样图卷积网络行为识别模型,在多流网络下进行端到端的训练.最后,基于NTU-RGB+D和NTU-RGB+D120骨架动作数据集开展了骨架行为识别的相关实验研究,研究结果表明该行为识别模型具有高效的时空特征提取能力以及优秀的性能. 展开更多
关键词 行为识别 时空采样图卷积 时空上下文 时域自校准 多流网络
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考虑预测误差时空相依性的短期风电功率概率预测 被引量:1
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作者 胡文慧 苏欣 +2 位作者 姜林 郭长星 杨茂 《南方电网技术》 CSCD 北大核心 2023年第2期137-144,共8页
由于风电功率点预测误差无法避免,概率预测可以充分描述风电功率的不确定性,进而对调度部门的决策提供进一步指导。当前的风电功率概率预测方法对其物理变化过程挖掘仍不完整。通过挖掘历史风电功率数据和数值天气预报(numerical weathe... 由于风电功率点预测误差无法避免,概率预测可以充分描述风电功率的不确定性,进而对调度部门的决策提供进一步指导。当前的风电功率概率预测方法对其物理变化过程挖掘仍不完整。通过挖掘历史风电功率数据和数值天气预报(numerical weather prediction,NWP)的时空特性,构建了一种考虑误差时空相依性的短期风电概率预测新框架。首先通过门控循环单元(gated recurrent unit,GRU)得到点预测结果;进而,引入多位置NWP,提出了一种考虑时空相依特性的多层次误差场景划分方法;最后,利用Bootstrap抽样法重构形成新的适应建模的误差样本集,进行了不同置信水平下的短期风电功率概率预测。由此得出,在考虑时空相依性的概率预测下,整体框架的效果在中国东北某风电场被验证,对比相同置信水平下,预测精度得到有效明显提高,且评价指标预测区间覆盖率提高0.53%、0.44%、0.32%,预测区间平均带宽缩小2.40%、2.14%,0.06%,证实了所提方法的有效性和可行性。 展开更多
关键词 时空相依性 风电功率短期概率预测 层次聚类 门控循环单元 Bootstrap抽样法
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基于时空信息转换方程的药品销量预测模型 被引量:1
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作者 靳东辉 杨小博 郭炳晖 《计算机应用》 CSCD 北大核心 2023年第S01期107-111,共5页
针对药品销售中高维短时间序列预测问题,利用时空信息转换方程及储备池计算方法构建了一种基于时空信息(STI)转换方程的药品销售量预测模型。首先针对药品销售时间序列数据样本量较小的特点,引入储备池计算方法拓展数据样本信息维度,将... 针对药品销售中高维短时间序列预测问题,利用时空信息转换方程及储备池计算方法构建了一种基于时空信息(STI)转换方程的药品销售量预测模型。首先针对药品销售时间序列数据样本量较小的特点,引入储备池计算方法拓展数据样本信息维度,将多个不同药品销售量时序数据中的动力学信息引入储备池。使用时空信息转换方程对时间信息与空间信息进行转化,最后在储备池运算的基础上对时空信息转化方程求解,对目标药品的销售量进行有效的时间序列预测。通过将提出的基于时空信息转换方程的时序预测模型与神经网络预测模型在特定药品销售数据集进行时序预测验证并进行横向对比,相较于GRU(Gated Recurrent Unit),所提模型在测试时间节点上的均方根误差(MSE)及运算时间分别减小了13.27%和95.60%、皮尔逊相关系数提高了34个百分点;相较于长短期记忆模型(LSTM),所提模型在测试时间节点上的均方根误差及运算时间分别减小了69.85%和98.00%,而皮尔逊相关系数提高了44个百分点;相较于卷积神经网络模型(CNN),在测试节点的均方根误差及运算时间分别减少了48.96%和88.53%,皮尔逊相关系数提高了33个百分点。证明了基于时空信息转换方程的药品销售预测模型在测试集时间节点上的预测效果要优于GRU、LSTM、CNN时序预测模型,同时也说明模型具有更高的运算效率。 展开更多
关键词 医药销售 小样本学习 时序预测 时空信息转换方程 储备池计算 相关性分析
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结合编码信息与超分辨率重建的视频编码方法
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作者 贾奇才 林宏伟 +1 位作者 田子溢 王创 《福建电脑》 2023年第7期21-24,共4页
如何在现有的视频压缩编码框架下保证视频质量的同时,大大降低压缩后视频的码率,仍是一个亟待解决的问题。本文根据现有的视频编码框架高效视频编码,提出了一种结合高效视频编码编码信息与时/空域超分辨率重建的视频编码方法。本系统预... 如何在现有的视频压缩编码框架下保证视频质量的同时,大大降低压缩后视频的码率,仍是一个亟待解决的问题。本文根据现有的视频编码框架高效视频编码,提出了一种结合高效视频编码编码信息与时/空域超分辨率重建的视频编码方法。本系统预先通过时间域自适应抽帧和空间域下采样分别降低了原视频的帧率和空间分辨率,然后通过标准化编解码器进行编码。在解码端,利用基于视频压缩码流信息的时域超分辨算法,将解码后的视频帧率增加到原始视频帧率。最后通过空域超分辨算法将视频重建恢复到原始分辨率。实验结果表明,相较于标准传统HEVC视频编码框架,本文所提出的算法在低码率段极大地降低了压缩视频的码率,同时降低了解码端超分辨重建过程的复杂度。 展开更多
关键词 时空下采样 码流信息 新一代高效视频编码 超分辨重建
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Comprehensive simulation of metagenomic sequencing data with non-uniform sampling distribution
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作者 Shansong Liu Kui Hua +1 位作者 Sijie Chen Xuegong Zhang 《Frontiers of Electrical and Electronic Engineering in China》 CSCD 2018年第2期175-185,共11页
Background: Metagenomic sequencing is a complex sampling procedure from unknown mixtures of many genomes. Having metagenome data with known genome compositions is essential for both benchmarking bioinformatics softwa... Background: Metagenomic sequencing is a complex sampling procedure from unknown mixtures of many genomes. Having metagenome data with known genome compositions is essential for both benchmarking bioinformatics software and for investigating influences of various factors on the data. Compared to data from real microbiome samples or from defined microbial mock community, simulated data with proper computational models are better for the purpose as they provide more flexibility for controlling multiple factors. Methods: We developed a non-uniform metagenomic sequencing simulation system (nuMetaSim) that is capable of mimicking various factors in real metagenomic sequencing to reflect multiple properties of real data with customizable parameter settings. Results: We generated 9 comprehensive metagenomic datasets with different composition complexity from of 203 bacterial genomes and 2 archaeal genomes related with human intestine system. Conclusion: The data can serve as benchmarks for comparing performance of different methods at different situations, and the software package allows users to generate simulation data that can better reflect the specific properties in their scenarios. 展开更多
关键词 SIMULATION metagenomic sequencing data non-uniform sampling nuMetaSim
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旅游客源市场抽样调查信息有效化途径研究 被引量:18
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作者 粟路军 黄福才 《旅游学刊》 CSSCI 北大核心 2009年第4期24-28,共5页
旅游客源市场调查是获取旅游市场基础资料与信息的重要途径,多采用抽样调查方法完成,因此,抽样调查获取的信息有效性是旅游市场研究科学性的前提与基础。在抽样调查具体实施过程中,发现该方法在信息有效性方面存在不尽完美的地方,需要... 旅游客源市场调查是获取旅游市场基础资料与信息的重要途径,多采用抽样调查方法完成,因此,抽样调查获取的信息有效性是旅游市场研究科学性的前提与基础。在抽样调查具体实施过程中,发现该方法在信息有效性方面存在不尽完美的地方,需要加以研究与改进。本文在细致考察旅游客源市场特殊性的基础上,对旅游客源市场抽样调查信息有效化途径进行分析,提炼了一套技术线路,提出多时空配比抽样调查方法,以提高旅游客源市场抽样调查信息有效性,为旅游业发展提供可靠的市场信息支持。 展开更多
关键词 旅游客源市场 抽样调查 时空配比 信息有效化
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路边空气污染移动测量的预处理方法 被引量:4
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作者 王占永 余然 +1 位作者 蔡铭 彭仲仁 《河南科技大学学报(自然科学版)》 CAS 北大核心 2017年第4期98-104,共7页
用移动测量平台对路边空气污染进行测量时,其结果易受异常高值样本、污染背景、时空尺度等因素干扰。评述了异常高值样本剔除、背景校正和时空尺度选择等数据预处理方法,并利用上海市某路边环境中细颗粒物(PM2.5)、超细颗粒物(PM1.0)、... 用移动测量平台对路边空气污染进行测量时,其结果易受异常高值样本、污染背景、时空尺度等因素干扰。评述了异常高值样本剔除、背景校正和时空尺度选择等数据预处理方法,并利用上海市某路边环境中细颗粒物(PM2.5)、超细颗粒物(PM1.0)、黑碳(BC)及一氧化碳(CO)的实测数据,对所选典型方法进行了验证。研究结果表明:针对上述污染物的移动测量,平滑变异系数法可合理剔除其异常高值样本,薄板样条回归平滑法可表征其背景值的时间变化特征,异常高值样本和背景的剔除可增强污染物分布的可比性。相关系数法进一步表明:10 s和20 m的时间和空间尺度组合能更有效地过滤数据噪音并能客观展现污染物指标的空间格局。 展开更多
关键词 交通污染 移动测量 异常样本 背景校正 时空尺度
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植物样品中内源性植物激素时空分布的研究进展 被引量:7
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作者 李玉璇 段春凤 关亚风 《色谱》 CAS CSCD 北大核心 2019年第8期806-814,共9页
内源性植物激素是在植物体中合成,并在整个植物生命周期内调控其生长发育、应对外界刺激等过程中发挥重要作用的一类微量或痕量有机小分子化合物。随着植物激素分析方法的发展,分析样品用量逐渐减少,不同植物组织(或器官)中植物激素的... 内源性植物激素是在植物体中合成,并在整个植物生命周期内调控其生长发育、应对外界刺激等过程中发挥重要作用的一类微量或痕量有机小分子化合物。随着植物激素分析方法的发展,分析样品用量逐渐减少,不同植物组织(或器官)中植物激素的种类和含量差异不断呈现,极大促进了植物激素生理作用的研究。近年来,植物样品中内源性植物激素的时空分布研究已成为植物激素分析的一大热点。该文总结了近五年来,内源性植物激素时空分布的研究进展,主要从分析难点、分析方法、主要植物激素在植物体内的时空分布情况等方面进行讨论和总结,相关内容围绕本研究组在植物激素检测方面的工作展开。最后,展望了植物激素时空分析这一研究领域的未来发展方向。 展开更多
关键词 液相色谱-质谱 样品前处理 时空分布 植物激素 综述
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Imputation of Mean of Ratios for Missing Data and Its Application to PPSWR Sampling 被引量:1
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作者 Guo Hua ZOU Ying Fu LI +1 位作者 Rong ZHU Zhong GUAN 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2010年第5期863-874,共12页
In practical survey sampling, nonresponse phenomenon is unavoidable. How to impute missing data is an important problem. There are several imputation methods in the literature. In this paper, the imputation method of ... In practical survey sampling, nonresponse phenomenon is unavoidable. How to impute missing data is an important problem. There are several imputation methods in the literature. In this paper, the imputation method of the mean of ratios for missing data under uniform response is applied to the estimation of a finite population mean when the PPSWR sampling is used. The imputed estimator is valid under the corresponding response mechanism regardless of the model as well as under the ratio model regardless of the response mechanism. The approximately unbiased jackknife variance estimator is also presented. All of these results are extended to the case of non-uniform response. Simulation studies show the good performance of the proposed estimators. 展开更多
关键词 IMPUTATION item nonresponse jackknife variance estimator non-uniform response PP-SWR sampling
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Linearized Phase Detector Zero Crossing DPLL Performance Evaluation in Faded Mobile Channels 被引量:1
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作者 Qassim Nasir Saleh Al-Araji 《Circuits and Systems》 2011年第3期139-144,共6页
Zero Crossing Digital Phase Locked Loop with Arc Sine block (AS-ZCDPLL) is used to linearize the phase difference detection, and enhance the loop performance. The loop has faster acquisition, less steady state phase e... Zero Crossing Digital Phase Locked Loop with Arc Sine block (AS-ZCDPLL) is used to linearize the phase difference detection, and enhance the loop performance. The loop has faster acquisition, less steady state phase error, and wider locking range compared to the conventional ZCDPLL. This work presents a Zero Crossing Digital Phase Locked Loop with Arc Sine block (ZCDPLL-AS). The performance of the loop is analyzed under mobile faded channel conditions. The mobile channel is assumed to be two path fading channel corrupted by additive white Gaussian noise (AWGM). It is shown that for a constant filter gain, the frequency spread has no effect on the steady state phase error variance when the loop is subjected to a phase step. For a frequency step and under the same conditions, the effect on phase error is minimal. 展开更多
关键词 non-uniform sampling Digital Phase Locked LOOPS ZERO CROSSING DPLL Mobile Faded CHANNELS
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The Irregular Weighted Wavelet Frame Conjugate Gradient Algorithm
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作者 Jiang Li Yi Aichun +1 位作者 Zhang Changfan Zhu Shanhua 《China Communications》 SCIE CSCD 2007年第4期48-54,共7页
The dropping off of data during information transmission and the storage device’s damage etc.often leads the sampled data to be non-uniform.The paper, based on the stability theory of irregular wavelet frame and the ... The dropping off of data during information transmission and the storage device’s damage etc.often leads the sampled data to be non-uniform.The paper, based on the stability theory of irregular wavelet frame and the irregular weighted wavelet frame operator,proposed an irregular weighted wavelet fame conjugate gradient iterative algorithm for the reconstruction of non-uniformly sampling signal. Compared the experiment results with the iterative algorithm of the Ref.[5],the new algorithm has remarkable advantages in approximation error,running time and so on. 展开更多
关键词 non-uniform sampling FRAME ALGORITHM IRREGULAR WAVELET FRAME CONJUGATE gradient ALGORITHM
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A New Method for Ride Quality Analysis of Vehicle
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作者 林建辉 张洁 +1 位作者 高燕 李天瑞 《Journal of Donghua University(English Edition)》 EI CAS 2006年第6期134-136,共3页
Current spectral analysis for evaluating the rail ride quality effectively is based on the sampling data at a uniform time interval, but the train is of fluctuation velocity in motion, which results in a non-uniform i... Current spectral analysis for evaluating the rail ride quality effectively is based on the sampling data at a uniform time interval, but the train is of fluctuation velocity in motion, which results in a non-uniform interval between consecutive sampling data. Therefore the accuracy of routine spectral analysis is in doubt when applying it in evaluating the rail ride quality. This paper presents a new way, namely, re-sampling with variable frequency to eliminate the influence of the train's uneven velocity. Its feature is that there is no need for precision measurement of the train's moving speed. Experiment results from the test-bed of rolling stock vibration show that it is valid. 展开更多
关键词 rail ride quality non-uniform sample resample and reconstitute signal processing.
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Fixed Point Iteration Chaos Controlled ZCDPLL
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作者 Qassim Nasir 《International Journal of Communications, Network and System Sciences》 2016年第11期535-544,共11页
The stable operation of first and second order Zero Crossing Digital Phase Locked Loop (ZCDPLL) is extended by using a Fixed Point Iteration (FPI) method with relaxation. The non-linear components of ZCDPLL such as sa... The stable operation of first and second order Zero Crossing Digital Phase Locked Loop (ZCDPLL) is extended by using a Fixed Point Iteration (FPI) method with relaxation. The non-linear components of ZCDPLL such as sampler phase detector and Digital Controlled Oscillator (DCO) lead to unstable and chaotic operation when the filter gains are high. FPI will be used to stabilize the chaotic operation and consequently extend the lock range of the loop. The proposed stabilized loop can work in higher filter gains which are needed for faster signal acquisition. 展开更多
关键词 non-uniform sampling Digital Phase Locked Loops Zero Crossing DPLL Chaos Control
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