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A new approach for pseudo hyperbolic partial differential equations with nonLocal conditions using Laplace Adomian decomposition method
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作者 Mahmut Modanli Sadeq Taha Abdulazeez Ahmad Muhamad Husien 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2024年第4期750-758,共9页
This paper provides a nonlinear pseudo-hyperbolic partial differential equation with non-local conditions.Despite the importance of this problem,the exact solution to this problem is rare in the literature.Therefore,t... This paper provides a nonlinear pseudo-hyperbolic partial differential equation with non-local conditions.Despite the importance of this problem,the exact solution to this problem is rare in the literature.Therefore,the Laplace-Adomian Decomposition Method(LADM)is used to provide a new approach to solving this problem.Additionally,we give a comparison between the exact and approximate solutions at various points with absolute error.The obtained result showed that the proposed method is effective and accurate for this problem and can be used for many other evolution of nonlinear equations in mathematical physics. 展开更多
关键词 pseudo hyperbolic equations nonlocal conditions Laplace-Adomian decomposition method Approximate solutions
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基于高斯滤波的双目相机三维目标检测Pseudo-LiDAR改进算法研究
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作者 李艳明 苏建强 +1 位作者 刘鹏 张丽杰 《光学技术》 CAS CSCD 北大核心 2024年第6期713-720,共8页
Pseudo-LiDAR算法作为双目相机三维目标检测的通用算法之一,因其低成本的立体视觉方案及出色的适应性被广泛应用于在自动驾驶、机器人等领域。但该算法在预测物体边缘会产生过多畸变点从而导致目标与背景之间过渡区域估计误差大;且深度... Pseudo-LiDAR算法作为双目相机三维目标检测的通用算法之一,因其低成本的立体视觉方案及出色的适应性被广泛应用于在自动驾驶、机器人等领域。但该算法在预测物体边缘会产生过多畸变点从而导致目标与背景之间过渡区域估计误差大;且深度估计网络采用四分支结构,计算量大影响运行速度。对以上问题,将Pseudo-LiDAR算法中的Spatial Pyramid Pooling(SPP)四分支结构优化为单分支结构,提高运行速度;创新性构造高斯置信度滤波模块,滤除过渡区域误差大的数据;引入PointVoxel-RCNN(PV-RCNN)作为Pseudo-LiDAR算法中的三维目标检测网络,提升检测精度。在KITTI数据集上的实验结果表明,相较于原算法,在简单、中等和困难等级下的车辆目标三维检测平均精度分别提升了22.36%、26.48%和28.55%。 展开更多
关键词 三维目标检测 双目相机 高斯置信度 pseudo-LiDAR算法
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Pseudo channel:time embedding for motor imagery decoding
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作者 MIAO Zhengqing ZHAO Meirong 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2024年第3期308-317,共10页
Motor imagery(MI)based electroencephalogram(EEG)represents a frontier in enabling direct neural control of external devices and advancing neural rehabilitation.This study introduces a novel time embedding technique,te... Motor imagery(MI)based electroencephalogram(EEG)represents a frontier in enabling direct neural control of external devices and advancing neural rehabilitation.This study introduces a novel time embedding technique,termed traveling-wave based time embedding,utilized as a pseudo channel to enhance the decoding accuracy of MI-EEG signals across various neural network architectures.Unlike traditional neural network methods that fail to account for the temporal dynamics in MI-EEG in individual difference,our approach captures time-related changes for different participants based on a priori knowledge.Through extensive experimentation with multiple participants,we demonstrate that this method not only improves classification accuracy but also exhibits greater adaptability to individual differences compared to position encoding used in Transformer architecture.Significantly,our results reveal that traveling-wave based time embedding crucially enhances decoding accuracy,particularly for participants typically considered“EEG-illiteracy”.As a novel direction in EEG research,the traveling-wave based time embedding not only offers fresh insights for neural network decoding strategies but also expands new avenues for research into attention mechanisms in neuroscience and a deeper understanding of EEG signals. 展开更多
关键词 motor imagery(MI) pseudo channel electroencephalogram(EEG) neural networks
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Long‐life lithium batteries enabled by a pseudo‐oversaturated electrolyte
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作者 Youchun Yu Simeng Wang +6 位作者 Juyan Zhang Weiwei Qian Nana Zhang Guangjie Shao Haiyan Bian Yuwen Liu Lan Zhang 《Carbon Energy》 SCIE EI CAS CSCD 2024年第4期115-127,共13页
The specific energy of Li metal batteries(LMBs)can be improved by using high‐voltage cathode materials;however,achieving long‐term stable cycling performance in the corresponding system is particularly challenging f... The specific energy of Li metal batteries(LMBs)can be improved by using high‐voltage cathode materials;however,achieving long‐term stable cycling performance in the corresponding system is particularly challenging for the liquid electrolyte.Herein,a novel pseudo‐oversaturated electrolyte(POSE)is prepared by introducing 1,1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropyl ether(TTE)to adjust the coordination structure between diglyme(G2)and lithium bis(trifluoromethanesulfonyl)imide(LiTFSI).Surprisingly,although TTE shows little solubility to LiTFSI,the molar ratio between LiTFSI and G2 in the POSE can be increased to 1:1,which is much higher than that of the saturation state,1:2.8.Simulation and experimental results prove that TTE promotes closer contact of the G2 molecular with Li^(+)in the POSE.Moreover,it also participates in the formation of electrolyte/electrode interphases.The electrolyte shows outstanding compatibility with both the Li metal anode and typical high‐voltage cathodes.Li||Li symmetric cells show a long life of more than 2000 h at 1 mA cm^(−2),1 mAh cm^(−2).In the meantime,Li||LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cell with the POSE shows a high reversible capacity of 134.8 mAh g^(−1 )after 900 cycles at 4.5 V,1 C rate.The concept of POSE can provide new insight into the Li^(+)solvation structure and in the design of advanced electrolytes for LMBs. 展开更多
关键词 high voltage lithium metal batteries pseudo‐oversaturated electrolyte solid electrolyte interphases(SEI) solvation structure
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Laboratory Implementation of Direct Torque Controller based Speed Loop Pseudo Derivative Feedforward Controller for PMSM Drive
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作者 Prabhakaran Koothu Kesavan Umashankar Subramaniam Dhafer J.Almakhles 《CES Transactions on Electrical Machines and Systems》 EI CSCD 2024年第1期12-21,共10页
This paper,evaluate the effectiveness of a proposed speed loop pseudo derivative feedforward(PDFF)controller-based direct torque controller(DTC)for a PMSM drive against the performance of existing PI speed controller-... This paper,evaluate the effectiveness of a proposed speed loop pseudo derivative feedforward(PDFF)controller-based direct torque controller(DTC)for a PMSM drive against the performance of existing PI speed controller-based DTC and hysteresis current controller(HCC).The proposed PDFF-based speed regulator effectively reduces oscillation and overshoot associated with rotor angular speed,electromagnetic torque,and stator current.Two case studies,one using forward-to-reverse motoring operation and the other involving reverse-to-forward braking operation,has been validated to show the effectiveness of the proposed control strategy.The proposed controller's superior performance is demonstrated through experimental verification utilizing an FPGA controller for a 1.5 kW PMSM drive laboratory prototype. 展开更多
关键词 Direct torque control pseudo derivative feedforward controller Permanent magnet synchronous motor(PMSM)
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Pseudo S-Asymptotically(ω,c)-Periodic Solutions to Fractional Differential Equations of Sobolev Type
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作者 MAO Hang-ning CHANG Yong-kui 《Chinese Quarterly Journal of Mathematics》 2024年第3期295-306,共12页
In this paper,we firstly recall some basic results on pseudo S-asymptotically(ω,c)-periodic functions and Sobolev type fractional differential equation.We secondly investigate some existence of pseudo S-asymptotical... In this paper,we firstly recall some basic results on pseudo S-asymptotically(ω,c)-periodic functions and Sobolev type fractional differential equation.We secondly investigate some existence of pseudo S-asymptotically(ω,c)-periodic solutions for a semilinear fractional differential equations of Sobolev type.We finally present a simple example. 展开更多
关键词 pseudo S-asymptotically(ω c)-periodic functions Evolution equations Sobolev type Fractional differential equations Existence and uniqueness
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IgG4 Coronary Arteritis Presenting as a Cardiac Pseudo-Tumour
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作者 Elaine Mo-Chee Chau Catherine Yuet-Hung Wong Raymond Hin-Suen Liang 《Case Reports in Clinical Medicine》 2024年第9期345-352,共8页
We report on an unusual case presenting with a cardiac pseudo-tumour on echocardiogram, which corresponded to a large soft tissue mural thickening around the mid-right coronary artery. There were similar but not as th... We report on an unusual case presenting with a cardiac pseudo-tumour on echocardiogram, which corresponded to a large soft tissue mural thickening around the mid-right coronary artery. There were similar but not as thick mural lesions around other parts of the coronary arteries. The so-called “pigs-in-a-blanket” sign on computed tomography (CT) scan was pathognomonic of IgG4 coronary arteritis. The IgG4 level was grossly elevated at more than 10 times the upper limit of normal. Positron emission tomography (PET)-CT scans with 18F-fluoro-deoxy-glucose (FDG) and 68Ga-Fibroblast Activation Protein Inhibitor (FAPI) were performed to assess the extent of organ involvement of the IgG4-related disease. The patient was treated with 8 injections of rituximab with good serological response. However, the coronary arteritis findings on CT scan remained unchanged. 展开更多
关键词 IgG4-Related Disease Coronary Arteritis Cardiac pseudo-Tumour “Pigs-in-a-Blanket” Sign
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Pseudo-Semi-Overlap Functions-Based Fuzzy Rough Sets Applied to Image Edge Extraction
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作者 Ran Yin Minge Chen +2 位作者 Yu Liu Yafei Zhao Jianwei Li 《Journal of Applied Mathematics and Physics》 2024年第7期2347-2366,共20页
As an extension of overlap functions, pseudo-semi-overlap functions are a crucial class of aggregation functions. Therefore, (I, PSO)-fuzzy rough sets are introduced, utilizing pseudo-semi-overlap functions, and furth... As an extension of overlap functions, pseudo-semi-overlap functions are a crucial class of aggregation functions. Therefore, (I, PSO)-fuzzy rough sets are introduced, utilizing pseudo-semi-overlap functions, and further extended for applications in image edge extraction. Firstly, a new clustering function, the pseudo-semi-overlap function, is introduced by eliminating the symmetry and right continuity present in the overlap function. The relaxed nature of this function enhances its applicability in image edge extraction. Secondly, the definitions of (I, PSO)-fuzzy rough sets are provided, using (I, PSO)-fuzzy rough sets, a pair of new fuzzy mathematical morphological operators (IPSOFMM operators) is proposed. Finally, by combining the fuzzy C-means algorithm and IPSOFMM operators, a novel image edge extraction algorithm (FCM-IPSO algorithm) is proposed and implemented. Compared to existing algorithms, the FCM-IPSO algorithm exhibits more image edges and a 73.81% decrease in the noise introduction rate. The outstanding performance of (I, PSO)-fuzzy rough sets in image edge extraction demonstrates their practical application value. 展开更多
关键词 pseudo-Semi-Overlap Functions Fuzzy Rough Set Fuzzy Mathematical Morphology Image Edge Extraction
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基于CNN和Transformer交叉教学的半监督医学图像分割
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作者 杨云 胡雯青 +1 位作者 杨虹 吴亚男 《陕西科技大学学报》 北大核心 2025年第1期185-192,共8页
由于医学图像分割领域缺乏高质量的标注数据,半监督学习方法在医学图像语义分割任务中受到高度重视.为了充分利用卷积神经网络(Convolutional Neural Network,CNN)和Transformer在半监督学习中的优势,本文提出一种基于CNN与Transformer... 由于医学图像分割领域缺乏高质量的标注数据,半监督学习方法在医学图像语义分割任务中受到高度重视.为了充分利用卷积神经网络(Convolutional Neural Network,CNN)和Transformer在半监督学习中的优势,本文提出一种基于CNN与Transformer交叉教学的半监督医学图像分割方法.该方法将经典的深度协同训练从一致性正则化简化为交叉教学,利用循环伪标签方案使两个网络的预测差异转换为无监督损失,以鼓励两个网络具有一致的低熵预测.所提方法在ISIC 2018数据集上进行实验,在采用20%的标注比例时,Dice系数和Jaccard系数分别达到87.25%和79.17%,相比于监督U-Net++的训练结果分别提升了2.89%和3.53%,并且优于目前主流的半监督学习方法,验证了所提方法在半监督医学图像分割上的有效性和泛化性. 展开更多
关键词 半监督学习 图像语义分割 交叉教学 循环伪标签
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Acute Colonic Pseudo-Obstruction (ACPO): An Expanding Colon with Unusual Risk Factors
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作者 Kelly Schulte Alyson Terry +1 位作者 Grace Boyle Dmitriy Scherbak 《Open Journal of Internal Medicine》 2024年第2期167-174,共8页
The distention of the colon without mechanical or anatomical obstruction, Acute Colonic Pseudo-obstruction (ACPO), is a common condition occurring in the critically ill. ACPO in the setting of an acute pulmonary embol... The distention of the colon without mechanical or anatomical obstruction, Acute Colonic Pseudo-obstruction (ACPO), is a common condition occurring in the critically ill. ACPO in the setting of an acute pulmonary embolism and embolic stroke is a rarity. A 76-year-old female with shortness of breath, left hemiparesis and right-sided paresthesias presented with acute pulmonary embolism and acute infarcts of the left caudate nucleus, thalamus and occipital lobe. Her hospitalization was complicated with persistent distention of the large bowel without dilation of the small bowel. Empiric antibiotics were initiated without improvement and laboratory studies including Clostridium difficile were negative. She underwent nasogastric decompression and two decompressive colonoscopies with a resolution of her symptoms. This case illustrates an example of acute abdominal distension, without underlying etiology, in the setting of acute embolism of the pulmonary and cerebral vasculature. Early identification and action with decompressive colonoscopy were key to preventing further bowel damage or rupture. 展开更多
关键词 Acute Colonic pseudo-Obstruction ACPO Ogilvie’s Syndrome Colonic Dilation Acute Embolic Infarcts Cerebrovascular Accident Pulmonary Embolism PE
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基于马尔可夫过程的电动汽车电驱动系统共模干扰抑制方法研究
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作者 张长勇 陈炟名 张云蕾 《汽车技术》 北大核心 2025年第1期41-47,共7页
针对电动汽车电驱动系统的共模干扰问题,提出了一种基于马尔可夫(Markov)过程的三段式伪随机载波频率等效零矢量脉宽调制(PRF-AZSPWM)策略。在等效零矢量作用的基础上,该策略引入双态Markov链生成随机合成信号,使载波频率在一定范围内... 针对电动汽车电驱动系统的共模干扰问题,提出了一种基于马尔可夫(Markov)过程的三段式伪随机载波频率等效零矢量脉宽调制(PRF-AZSPWM)策略。在等效零矢量作用的基础上,该策略引入双态Markov链生成随机合成信号,使载波频率在一定范围内随机变化,同时选择合适的传递概率,将谐波能量扩展到更宽的频率范围。仿真结果表明,提出的方案有效降低了电驱动系统的共模干扰水平,并通过样机试验进一步证明了提出策略的有效性。 展开更多
关键词 电动汽车 电驱动系统 共模干扰 伪随机 马尔可夫过程
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基于核主成分分析的半监督日志异常检测模型
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作者 顾兆军 叶经纬 +2 位作者 刘春波 张智凯 王志 《江苏大学学报(自然科学版)》 CAS 北大核心 2025年第1期64-72,97,共10页
对于具有“组异常”和“局部异常”分布特点的系统日志数据,传统的ADOA(anomaly detection with partially observed anomalies)半监督日志异常检测方法存在为无标签数据生成的伪标签准确性不佳的问题.针对此问题,提出一种改进的半监督... 对于具有“组异常”和“局部异常”分布特点的系统日志数据,传统的ADOA(anomaly detection with partially observed anomalies)半监督日志异常检测方法存在为无标签数据生成的伪标签准确性不佳的问题.针对此问题,提出一种改进的半监督日志异常检测模型.对已知异常样本采用k均值聚类,采用核主成分分析计算无标签样本的重构误差;运用重构误差和异常样本相似分计算出样本的综合异常分,作为其伪标签;依据伪标签计算LightGBM分类器的样本权重,训练异常检测模型.通过参数试验探究了训练集样本比例变化对模型性能的影响.在HDFS和BGL这2个公开数据集上进行试验,结果表明该模型能够提高伪标签的准确性,相较于DeepLog、LogAnomaly、LogCluster、PCA和PLELog等已有模型,精确率和F 1分数均有提升.与传统的ADOA异常检测方法相比,该模型F 1分数在2类数据集上分别提高了0.084和0.085. 展开更多
关键词 系统日志 日志异常检测 组异常 局部异常 半监督 重构误差 核主成分分析 伪标签
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浅圆仓地震侧压力计算公式推导与分析
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作者 张国祥 曾荣 《地震工程学报》 北大核心 2025年第1期33-40,共8页
仓壁侧压力是浅圆仓抗震设计的重要参数,在规范中没有给出确切的浅圆仓仓壁地震侧压力的理论计算公式。对此,基于极限平衡法,将浅圆仓看作特殊的曲线挡墙,取单位弧长的滑动楔体为研究对象,采用拟静力法与旋转地震角法简化地震力以进行... 仓壁侧压力是浅圆仓抗震设计的重要参数,在规范中没有给出确切的浅圆仓仓壁地震侧压力的理论计算公式。对此,基于极限平衡法,将浅圆仓看作特殊的曲线挡墙,取单位弧长的滑动楔体为研究对象,采用拟静力法与旋转地震角法简化地震力以进行极限平衡分析,并推导出浅圆仓锥堆与平堆工况下的地震侧压力计算公式。通过算例分析,比较满仓状态下地震侧压力的实测数据值及理论计算值,初步验证公式的正确性。对地震侧压力进行数值模拟与参数分析,结果表明模型拟合效果良好,仓壁摩擦力影响较大,在计算中不可忽视;在平堆工况下半径取值对大直径浅圆仓地震侧压力的影响较小,可将其简化为直线挡墙计算。研究成果可为完善筒仓规范中地震侧压力的计算推导提供一定的参考依据。 展开更多
关键词 浅圆仓 极限平衡法 滑动楔体 地震侧压力 拟静力法 旋转地震角法
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基于Pseudo-Zernike不变矩的PNN车牌汉字识别 被引量:10
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作者 高全华 王晋国 孙锋利 《计算机工程》 CAS CSCD 北大核心 2009年第4期196-198,共3页
基于不变矩理论,提出一种应用概率神经网络作为识别器的车牌汉字识别技术。利用Pseudo-Zernike矩特征的旋转不变性和良好的抗噪性能,将其作为车牌汉字识别的特征矢量,结合Pseudo-Zernike矩的快速算法和概率神经网络识别器快速学习和识... 基于不变矩理论,提出一种应用概率神经网络作为识别器的车牌汉字识别技术。利用Pseudo-Zernike矩特征的旋转不变性和良好的抗噪性能,将其作为车牌汉字识别的特征矢量,结合Pseudo-Zernike矩的快速算法和概率神经网络识别器快速学习和识别的性能,可适应实时环境下所获取的车牌汉字灰度图像的识别,具有较高的准确率,实验结果表明了该方法的有效性。 展开更多
关键词 车牌识别 pseudo—Zernike不变矩 概率神经网络
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Depression effect of pseudo glycolythiourea acid in flotation separation of copper-molybdenum 被引量:14
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作者 陈建华 蓝丽红 廖幸锦 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第3期824-831,共8页
Pseudo glycolythiourea acid(PGA) was synthesized and used as depressant for flotation separation of Cu and Mo.The results indicate that a low amount of PGA has strong depression effect on chalcopyrite.Mo grade of 26... Pseudo glycolythiourea acid(PGA) was synthesized and used as depressant for flotation separation of Cu and Mo.The results indicate that a low amount of PGA has strong depression effect on chalcopyrite.Mo grade of 26.17% and recovery of 89.83% were achieved with rougher and scavenger one time and cleaners twice,while the recovery of Mo was deceased by 2% when Na2S was used as depressant.Measurement on adsorption of PGA on the mineral surface indicates that PGA and xanthate were adsorbed on mineral surface by competition,and PGA was adsorbed on chalcopyrite surface much stronger than on molybdenite surface.FTIR results indicate a chemical absorption process for PGA on chalcopyrite surface and a physical adsorption process on molybdenite surface.The frontier orbital calculation shows that the S atom is an active center,and the depression of PGA can be explained with the Fermi level of energy based on the electrochemical mechanism. 展开更多
关键词 pseudo glycolythiourea acid(PGA) CHALCOPYRITE MOLYBDENITE depressant Cu-Mo separation competitive adsorption
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Reservoir information extraction using a fractional Fourier transform and a smooth pseudo Wigner-Ville distribution 被引量:5
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作者 王祝文 王晓丽 +3 位作者 向旻 刘菁华 张雪昂 杨闯 《Applied Geophysics》 SCIE CSCD 2012年第4期391-400,494,495,共12页
Currently, it is difficult for people to express signal information simultaneously in the time and frequency domains when analyzing acoustic logging signals using a simple-time or frequency-domain method. It is diffic... Currently, it is difficult for people to express signal information simultaneously in the time and frequency domains when analyzing acoustic logging signals using a simple-time or frequency-domain method. It is difficult to use a single type of time-frequency analysis method, which affects the feasibility of acoustic logging signal analysis. In order to solve these problems, in this paper, a fractional Fourier transform and smooth pseudo Wigner Ville distribution (SPWD) were combined and used to analyze array acoustic logging signals. The time-frequency distribution of signals with the variation of orders of fractional Fourier transform was obtained, and the characteristics of the time-frequency distribution of different reservoirs under different orders were summarized. Because of the rotational characteristics of the fractional Fourier transform, the rotation speed of the cross terms was faster than those of primary waves, shear waves, Stoneley waves, and pseudo Rayleigh waves. By choosing different orders for different reservoirs according to the actual circumstances, the cross terms were separated from the four kinds of waves. In this manner, we could extract reservoir information by studying the characteristics of partial waves. Actual logging data showed that the method outlined in this paper greatly weakened cross-term interference and enhanced the ability to identify partial wave signals. 展开更多
关键词 Fractional Fourier transform smooth pseudo Wigner-Ville distribution arrayacoustic logging signal processing RESERVOIRS
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大亚湾拟菱形藻(Pseudon-itzschiaspp.)种群的季节变化与环境因子的关系 被引量:27
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作者 陈菊芳 徐宁 +4 位作者 王朝晖 黄伟建 谢隆初 江天久 齐雨藻 《环境科学学报》 CAS CSCD 北大核心 2002年第6期743-748,共6页
1997年 7月至 1998年 6月期间 ,对大亚湾海域拟菱形藻种群的季节变化及其与环境因子之间的关系进行研究 .高密度的拟菱形藻出现的温度、盐度范围分别在 2 5 0~ 30 0℃和 2 8 4 0‰~ 31 30‰ .该水域N、Si含量丰富 ,P含量偏低 ,通常... 1997年 7月至 1998年 6月期间 ,对大亚湾海域拟菱形藻种群的季节变化及其与环境因子之间的关系进行研究 .高密度的拟菱形藻出现的温度、盐度范围分别在 2 5 0~ 30 0℃和 2 8 4 0‰~ 31 30‰ .该水域N、Si含量丰富 ,P含量偏低 ,通常情况下 ,P成为拟菱形藻生长的限制因子 ,而春季高峰期中 ,拟菱形藻的消退主要可能与N的迅速耗尽有关 .N、Si、P三种营养盐之间比值的变化亦是影响拟菱形藻生长的重要原因 ,拟菱形藻高密度出现的N∶P、Si∶P、Si∶N范围分别是 6 .2 1~ 32 98、5 9 6 7~ 119 71、3 36~ 17 89. 展开更多
关键词 季节变化 拟菱形藻 大亚湾海域 种群动态 环境因子 海洋污染 赤潮 环境监测
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一种新的Pseudo-Zernike矩的快速算法 被引量:15
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作者 夏婷 周卫平 +1 位作者 李松毅 舒华忠 《电子学报》 EI CAS CSCD 北大核心 2005年第7期1295-1298,共4页
Zernike矩因具有正交性和旋转不变性而广泛应用于模式识别、图像分析等领域.Pseudo-Zernike矩具有与Zernike矩相似的性质,但它较Zernike矩具有更好的抗噪声性.由于pseudo-Zernike矩的复杂性,相关的快速算法的研究尚未得到很好的解决.本... Zernike矩因具有正交性和旋转不变性而广泛应用于模式识别、图像分析等领域.Pseudo-Zernike矩具有与Zernike矩相似的性质,但它较Zernike矩具有更好的抗噪声性.由于pseudo-Zernike矩的复杂性,相关的快速算法的研究尚未得到很好的解决.本文根据pseudo-Zernike矩自身的特点,推导了一种快速有效的计算方法. 展开更多
关键词 ZERNIKE矩 pseudo-Zernike矩 快速算法
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基于小波变换和拟动力法的边坡地震稳定性评价方法
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作者 钱法桥 邓亚虹 +3 位作者 慕焕东 杨楠 刘凡 王梦晨 《岩土力学》 北大核心 2025年第1期88-96,109,共10页
结合简化Bishop法,推导了地震作用下边坡的稳定性计算公式,包括拟静力法(pseudo-static method,简称PSM)、经典拟动力法(pseudo-dynamic method,简称PDM)和修正拟动力法(modified pseudo-dynamic method,简称MPDM)。其中,修正拟动力法... 结合简化Bishop法,推导了地震作用下边坡的稳定性计算公式,包括拟静力法(pseudo-static method,简称PSM)、经典拟动力法(pseudo-dynamic method,简称PDM)和修正拟动力法(modified pseudo-dynamic method,简称MPDM)。其中,修正拟动力法将土体视为Kelvin-Voigt材料,考虑了土体的黏弹特性和放大特性。在此基础上,对修正拟动力法进行了推广,使剪应力在坡顶、坡面处均为0,符合边坡应力特征。然后,基于Morlet小波分析,以El centro波为研究对象获得了地震波的频谱分布特征。通过提取峰值加速度PGA时刻的卓越频率,提出了一种考虑地震动时频特征的边坡地震稳定性评价方法。最后,将各方法与实例进行了验证。结果表明:拟动力法所需参数较少且意义明确,能够快速、准确地评价边坡地震稳定性,与时程分析方法结果接近。该研究成果可为边坡地震危险性评价、地震滑坡灾害范围分析预测、抗震应急抢险提供理论依据。 展开更多
关键词 拟动力 修正拟动力 小波变化 地震 滑坡 稳定性
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The Pseudo-umbilical Surfaces in R^4 and Their Gauss Maps 被引量:1
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作者 许志才 徐森林 《Chinese Quarterly Journal of Mathematics》 CSCD 2001年第1期46-51,共6页
Some properties of the pseudo umbilical surface M in R 4 are discussed and thus the lower for the tolal mean curvature of M is estimated. On the basis of the estimation and by using the Gauss map of M... Some properties of the pseudo umbilical surface M in R 4 are discussed and thus the lower for the tolal mean curvature of M is estimated. On the basis of the estimation and by using the Gauss map of M , a sufficient condition is given for M as a flat torus in R 4 . 展开更多
关键词 the pseudo umbilical surface total mean curvature Gauss map TORUS
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