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杂波背景下目标回波信号积累预置MTI的递归Radon-Fourier变换方法
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作者 汪海波 巴涛 +3 位作者 黄文华 张余川 庄俊 张海川 《系统工程与电子技术》 北大核心 2025年第9期2913-2924,共12页
雷达系统的时序被分成固定的相参处理间隔(coherent processing interval, CPI),只有接收完整个CPI内的回波数据,才能应用Radon傅里叶变换(Radon-Fourier transform,RFT)方法实现相参积累,导致系统的处理延时至少是一个CPI的长度。对此... 雷达系统的时序被分成固定的相参处理间隔(coherent processing interval, CPI),只有接收完整个CPI内的回波数据,才能应用Radon傅里叶变换(Radon-Fourier transform,RFT)方法实现相参积累,导致系统的处理延时至少是一个CPI的长度。对此,提出一种预置运动目标显示(pre-moving target indication, Pre-MTI)的递归RFT方法,突破RFT方法需要一个整个CPI回波数据的限制。每接收一次回波数据即可实施相参积累,理论上系统处理延时最短到与雷达工作重复周期相当。本文对算法的相参积累增益、相参积累时间和改善因子进行理论分析,给出相应的解析推导。仿真结果表明,通过Pre-MTI处理能够有效抑制杂波,递归RFT变换方法能够对运动目标回波实现有效积累,信噪比和速度分辨率随着递归的脉冲个数增加而增加。通过递归RFT变换方法实线相参积累的系统延时降低,理论上最短延时可达雷达重复周期。 展开更多
关键词 时距联合 相参积累 运动目标显示 Radon傅里叶变换
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Riesz变换在Fourier-Besov空间中的有界性研究
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作者 孟虹宇 彭磊 《哈尔滨师范大学自然科学学报》 2025年第1期10-14,共5页
Riesz变换与Riesz位势在偏微分方程方面的应用广泛,可以有效的表示出方程的算子半群或是估计方程的基本解.探究Riesz变换和Riesz位势在Fourier-Besov空间内的有界性,并证明了Riesz变换和Riesz位势在Fourier-Besov空间的有界性,这为Fouri... Riesz变换与Riesz位势在偏微分方程方面的应用广泛,可以有效的表示出方程的算子半群或是估计方程的基本解.探究Riesz变换和Riesz位势在Fourier-Besov空间内的有界性,并证明了Riesz变换和Riesz位势在Fourier-Besov空间的有界性,这为Fourier-Besov空间的有界性研究提供了新思路. 展开更多
关键词 RIESZ变换 RIESZ位势 fourier-Besov空间 有界性
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Walsh-Kaczmarz-Fourier级数在Orlicz空间中的Norlund平均逼近
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作者 刘倩 吴嘎日迪 《应用数学》 北大核心 2025年第2期542-552,共11页
本文讨论Walsh-Kaczmarz-Fourier级数在Orlicz空间内的Norlund平均逼近问题,借助Orlicz空间内的Holder不等式、Minkowski不等式和连续模等工具,给出了Norlund平均逼近速度的两种估计.文中结果包含Lp空间内的同类结果.
关键词 fourier级数 Norlund平均 ORLICZ空间 连续模
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卫星导航通道失真下伪距偏差Fourier分解模型
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作者 高涵博 林红磊 +1 位作者 欧钢 肖志斌 《导航定位学报》 北大核心 2025年第2期103-110,共8页
针对卫星导航系统收发通道失真引起的伪距测量偏差在不同接收机相关间隔下的不一致性问题,提出一种通道失真下的伪距偏差分解模型:利用通道群时延的傅里叶(Fourier)级数分解,以多径形式表征出接收信号在通道失真下的畸变相关函数及随接... 针对卫星导航系统收发通道失真引起的伪距测量偏差在不同接收机相关间隔下的不一致性问题,提出一种通道失真下的伪距偏差分解模型:利用通道群时延的傅里叶(Fourier)级数分解,以多径形式表征出接收信号在通道失真下的畸变相关函数及随接收机相关间隔变化的过零点偏差(SCB)曲线;在此基础上,利用SCB曲线分析通道参数对接收机不同相关间隔下伪距偏差的影响,提出满足不同一致性设计要求的滤波器参数设计。实验结果表明,提出的模型计算的理论SCB曲线与仿真曲线的均方根误差为7.9 mm,相比于传统模型的均方根误差可减小78%;该模型可为接收机通道优化设计提供分析工具,并为伪距测量校准提供参考。 展开更多
关键词 导航信道 伪距偏差 滤波器 相关函数 通道非理想 傅里叶级数
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Fast full-color pathological imaging using Fourier ptychographic microscopy via closed-form model-based colorization 被引量:2
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作者 Yanqi Chen Jiurun Chen +4 位作者 Zhiping Wang Yuting Gao Yonghong He Yishi Shi An Pan 《Advanced Photonics Nexus》 2025年第2期7-16,共10页
Full-color imaging is essential in digital pathology for accurate tissue analysis.Utilizing advanced optical modulation and phase retrieval algorithms,Fourier ptychographic microscopy(FPM)offers a powerful solution fo... Full-color imaging is essential in digital pathology for accurate tissue analysis.Utilizing advanced optical modulation and phase retrieval algorithms,Fourier ptychographic microscopy(FPM)offers a powerful solution for high-throughput digital pathology,combining high resolution,large field of view,and extended depth of field(DOF).However,the full-color capabilities of FPM are hindered by coherent color artifacts and reduced computational efficiency,which significantly limits its practical applications.Color-transferbased FPM(CFPM)has emerged as a potential solution,theoretically reducing both acquisition and reconstruction threefold time.Yet,existing methods fall short of achieving the desired reconstruction speed and colorization quality.In this study,we report a generalized dual-color-space constrained model for FPM colorization.This model provides a mathematical framework for model-based FPM colorization,enabling a closed-form solution without the need for redundant iterative calculations.Our approach,termed generalized CFPM(gCFPM),achieves colorization within seconds for megapixel-scale images,delivering superior colorization quality in terms of both colorfulness and sharpness,along with an extended DOF.Both simulations and experiments demonstrate that gCFPM surpasses state-of-the-art methods across all evaluated criteria.Our work offers a robust and comprehensive workflow for high-throughput full-color pathological imaging using FPM platforms,laying a solid foundation for future advancements in methodology and engineering. 展开更多
关键词 fourier ptychographic microscopy color transfer dual-color-space constrained model
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基于Exponent Fourier矩的双图像水印方法
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作者 刘西林 贺贤浩 +2 位作者 张昊 岳俊宏 陈泽华 《太原理工大学学报》 北大核心 2025年第3期474-484,共11页
【目的】针对目前大多数图像水印方案都设计为在单一图像中嵌入水印,会导致效率不够高的问题,探讨将水印同时嵌入两幅图像中,以在保证算法鲁棒性能的前提下提高效率。【方法】首先,通过复数表示法将两幅原始图像组合在一起。然后,采用... 【目的】针对目前大多数图像水印方案都设计为在单一图像中嵌入水印,会导致效率不够高的问题,探讨将水印同时嵌入两幅图像中,以在保证算法鲁棒性能的前提下提高效率。【方法】首先,通过复数表示法将两幅原始图像组合在一起。然后,采用量化调制的信息嵌入方法将水印嵌入到组合图像的Exponent Fourier矩中,通过修改前后的Exponent Fourier矩的扰动量重构图像生成补偿图像,将原始组合图像与补偿图像叠加得到嵌入水印的组合图像。最后,对嵌入水印的组合图像进行分解,得到两幅加水印的图像。在提取水印时,需要两幅加入水印的图像,然后进行组合,在组合后的图像中提取水印。【结果】实验验证了所提方法的可行性和其较强的鲁棒性,与传统PCET矩的水印方法相比,所提水印方法对5×5中值滤波、5×5均值滤波、方差为0.03的高斯噪声、噪声密度为0.03的椒盐噪声、压缩因子为10的JPEG压缩攻击,其BER值分别降低了36%、44%、45%、59%、29%;在提取水印时,与分别处理两幅图像相比,提取时间缩短了50%。 展开更多
关键词 图像水印 双图像水印 Exponent fourier
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A Programming Method for Mean Behavior of Fourier Coefficients of Modular Forms on Sparse Sequences
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作者 HU Yuanrui YAO Weili 《数学进展》 北大核心 2025年第4期709-724,共16页
Let f be a primitive holomorphic cusp form with even integral weight k≥2 for the full modular groupΓ=SL(2,Z)andλ_(sym^(j)f)(n)be the n-th coefficient of Dirichlet series of j-th symmetric L-function L(s,sym^(j)f)at... Let f be a primitive holomorphic cusp form with even integral weight k≥2 for the full modular groupΓ=SL(2,Z)andλ_(sym^(j)f)(n)be the n-th coefficient of Dirichlet series of j-th symmetric L-function L(s,sym^(j)f)attached to f.In this paper,we study the mean value distribution over a specific sparse sequence of positive integers of the following sum∑(a^(2)+b^(2)+c^(2)+d^(2)≤x(a,b,c,d)∈Z^(4))λ_(sym^(j))^(i)f(a^(2)+b^(2)+c^(2)+d^(2))where j≥2 is a given positive integer,i=2,3,4 andαis sufficiently large.We utilize Python programming to design algorithms for higher power conditions,combining Perron's formula,latest results of representations of natural integers as sums of squares,as well as analytic properties and subconvexity and convexity bounds of automorphic L-functions,to ensure the accuracy and verifiability of asymptotic formulas.The conclusion we obtained improves previous results and extends them to a more general settings. 展开更多
关键词 automorphic L-function holomorphic cusp form fourier coefficient
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AI-driven Fourier Ptychography and Its Insight for“AI+Optics”(Invited)
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作者 PAN An WANG Aiye +4 位作者 FENG Tianci GAO Huiqin WANG Siyuan XU Jinghao LI Xuan 《光子学报》 北大核心 2025年第9期146-170,共25页
Fourier Ptychographic Microscopy(FPM)is a high-throughput computational optical imaging technology reported in 2013.It effectively breaks through the trade-off between high-resolution imaging and wide-field imaging.In... Fourier Ptychographic Microscopy(FPM)is a high-throughput computational optical imaging technology reported in 2013.It effectively breaks through the trade-off between high-resolution imaging and wide-field imaging.In recent years,it has been found that FPM is not only a tool to break through the trade-off between field of view and spatial resolution,but also a paradigm to break through those trade-off problems,thus attracting extensive attention.Compared with previous reviews,this review does not introduce its concept,basic principles,optical system and series of applications once again,but focuses on elaborating the three major difficulties faced by FPM technology in the process from“looking good”in the laboratory to“working well”in practical applications:mismatch between numerical model and physical reality,long reconstruction time and high computing power demand,and lack of multi-modal expansion.It introduces how to achieve key technological innovations in FPM through the dual drive of Artificial Intelligence(AI)and physics,including intelligent reconstruction algorithms introducing machine learning concepts,optical-algorithm co-design,fusion of frequency domain extrapolation methods and generative adversarial networks,multi-modal imaging schemes and data fusion enhancement,etc.,gradually solving the difficulties of FPM technology.Conversely,this review deeply considers the unique value of FPM technology in potentially feeding back to the development of“AI+optics”,such as providing AI benchmark tests under physical constraints,inspirations for the balance of computing power and bandwidth in miniaturized intelligent microscopes,and photoelectric hybrid architectures.Finally,it introduces the industrialization path and frontier directions of FPM technology,pointing out that with the promotion of the dual drive of AI and physics,it will generate a large number of industrial application case,and looks forward to the possibilities of future application scenarios and expansions,for instance,body fluid biopsy and point-of-care testing at the grassroots level represent the expansion of the growth market. 展开更多
关键词 Computational optical imaging fourier ptychography Artificial Intelligence Highthroughput imaging Multimodal imaging
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Assessment of Optimal Use, Maintenance, Repair and Calibration of Radiation Monitoring Instruments in Nigeria
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作者 Samuel Mofolorunsho Oyeyemi Olumide Olaife Akerele +5 位作者 Sunday Ufuoma Obarhua Francis Adole Agada Wasiu Kofoworola Ayuba Helen Enikpi Alakiu David Olakanmi Olaniyi Ethel Ebere Ofoegbu 《World Journal of Nuclear Science and Technology》 2025年第1期1-16,共16页
The response and performance of radiation detectors for accurate measurements and effective use for radiological safety in medical, industrial, and nuclear sectors are based on the optimal use, maintenance, repair and... The response and performance of radiation detectors for accurate measurements and effective use for radiological safety in medical, industrial, and nuclear sectors are based on the optimal use, maintenance, repair and calibration of radiation monitoring instruments in a secondary standard dosimetry laboratory. In Nigeria, the suboptimal performances of these instruments are attributed to inadequate maintenance practices, insufficient calibration, and limited awareness of proper equipment handling for optimal use. This study assesses the current practices related to the optimal use, maintenance, repair, and calibration of radiation detection equipment across Nigeria’s six geopolitical zones. Using a cross-sectional survey approach, data were collected from Ninety (90) radiation monitoring equipment operators, Radiation Safety Officers, and frontline responders to evaluate their knowledge, awareness, and practices concerning equipment usage, operation, storage, handling, and calibration. The findings reveal significant gaps in knowledge of usage (trained is 43.2%, not trained is 56.8%) and inconsistencies in maintenance practices (as indicated by the regression analysis (β = 0.51, p < 0.01), particularly regarding specialized instruments such as the PackEye, Mobile Detection System (MDS), Radionuclide Identifinder (RID), and Personal Radiation Detectors (PRD). While there is high awareness of the need for regular calibration and handling training, the lack of standardized protocols and training alignment poses challenges to the effective use of these instruments. This study underscores the importance of comprehensive training programs, standardized maintenance protocols, and enhanced awareness initiatives to optimize the usage, performance and safety of radiation monitoring instruments in Nigeria. 展开更多
关键词 Radiation Monitoring instruments Detectors CALIBRATION Radiation Safety Officers PackEye Radionuclide Identifinder Personal Radiation Detectors
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算术数列中Fourier系数的均值估计
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作者 武毅 《兰州文理学院学报(自然科学版)》 2025年第1期1-6,共6页
设f(z)是全模群上权为偶数k的全纯本原尖形式,L(s,sym^(4)f)是与f对应的4次对称幂L-函数,λ_(sym^(4)f)(n)是L(s,sym^(4)f)的Fourier展开的第n个标准化系数.本文借助对称幂L-函数的解析性质研究了算术数列中4次对称幂L-函数Fourier系数... 设f(z)是全模群上权为偶数k的全纯本原尖形式,L(s,sym^(4)f)是与f对应的4次对称幂L-函数,λ_(sym^(4)f)(n)是L(s,sym^(4)f)的Fourier展开的第n个标准化系数.本文借助对称幂L-函数的解析性质研究了算术数列中4次对称幂L-函数Fourier系数的均值估计,即Σ_(n≤x,n≡l(q))λ_(sym^(4)f)(n^(2)). 展开更多
关键词 全纯本原尖形式 对称幂L-函数 算术数列 fourier系数
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The Impact of Quality Nursing on Instrument Quality Management and Department Satisfaction in the Management of Reusable Instruments in the Central Sterile Supply Department
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作者 Jie Li 《Journal of Clinical and Nursing Research》 2025年第6期385-391,共7页
Objective:To evaluate the effectiveness of quality nursing in the management of reusable instruments in the Central Sterile Supply Department(CSSD).Methods:Eleven nurses from the CSSD department were selected from Jan... Objective:To evaluate the effectiveness of quality nursing in the management of reusable instruments in the Central Sterile Supply Department(CSSD).Methods:Eleven nurses from the CSSD department were selected from January to October 2024,and quality nursing activities were implemented in the management of reusable instruments.The completion of quality indicators was analyzed.The instrument quality management scores,department satisfaction,and nurses’professional ability scores before and after nursing management were compared.Results:After nursing intervention,the qualified rates of initial cleaning and final cleaning of sterilization instruments were 99.66%and 100%,respectively.The qualified rate of packaging was 99.97%,the wet package rate was 0.1‰,the loading qualified rate was 99.88%,and the qualified rate of distribution was 99.99%.After nursing intervention,the nurses’instrument quality management scores,department satisfaction,and nurses’professional ability scores were all higher than those before nursing intervention(P<0.05).Conclusion:Quality nursing activities can improve the cleaning,packaging,and sterilization qualified rates of reusable instruments in the CSSD,enhance the effect of instrument quality management,obtain higher department satisfaction from nurses,cultivate their professional abilities,and possess significant nursing management advantages. 展开更多
关键词 Quality nursing Central Sterile Supply Department Reusable instrument management Instrument quality management Department satisfaction
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强非退化条件下Fourier积分算子的加权估计
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作者 刘亚兵 陶双平 《湖北大学学报(自然科学版)》 2025年第4期517-521,共5页
本工作主要目的是研究Fourier积分算子的加权估计并证明当a∈S_(ρ,δ)^(m),0<ρ≤1,0≤δ<1,Ф∈Φ^(2)时,在强非退化条件m=ρ-n/2下,Fourier积分算子T_(φ,a)在加权L^(p)空间上是有界的。
关键词 fourier积分算子 Hörmander类 加权L^(p)空间 A_(p)权
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Application and Innovation of Automotive Electronics Structural Design in Center Console Instruments
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作者 Peijie Jia 《Journal of Electronic Research and Application》 2025年第4期320-326,共7页
This paper introduces the key design aspects of automotive center console instrument systems,including hardware architecture,ergonomics,antenna layout,etc.It elaborates on the application and advantages of various adv... This paper introduces the key design aspects of automotive center console instrument systems,including hardware architecture,ergonomics,antenna layout,etc.It elaborates on the application and advantages of various advanced technologies,such as 3D printing and dual-color injection molding.Additionally,it discusses advancements in structural design,as well as future challenges and the trend of multidisciplinary collaborative innovation. 展开更多
关键词 Automotive center console instrument Structural design Technology application
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Fourier lightfield multiview stereoscope for large field-of-view 3D imaging in microsurgical settings
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作者 Clare B.Cook Kevin C.Zhou +8 位作者 Martin Bohlen Mark Harfouche Kanghyun Kim Paul Reamey Julia S.Foust Gregor Horstmeyer Ramana Balla Amey Chaware Roarke Horstmeyer 《Advanced Photonics Nexus》 2025年第4期74-88,共15页
We present the Fourier lightfield multiview stereoscope(FiLM-Scope).This imaging device combines concepts from Fourier lightfield microscopy and multiview stereo imaging to capture high-resolution 3D videos over large... We present the Fourier lightfield multiview stereoscope(FiLM-Scope).This imaging device combines concepts from Fourier lightfield microscopy and multiview stereo imaging to capture high-resolution 3D videos over large fields of view.The FiLM-Scope optical hardware consists of a multicamera array,with 48 individual microcameras,placed behind a high-throughput primary lens.This allows the FiLM-Scope to simultaneously capture 48 unique 12.8 megapixel images of a 28×37 mm field-of-view,from unique angular perspectives over a 21 deg×29 deg range,with down to 22μm lateral resolution.We also describe a self-supervised algorithm to reconstruct 3D height maps from these images.Our approach demonstrates height accuracy down to 11μm.To showcase the utility of our system,we perform tool tracking over the surface of an ex vivo rat skull and visualize the 3D deformation in stretching human skin,with videos captured at up to 100 frames per second.The FiLM-Scope has the potential to improve 3D visualization in a range of microsurgical settings. 展开更多
关键词 3D imaging fourier light field camera array
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Fourier neural operator for high-resolution fluid flow simulation based on low-resolution data:the vorticity equation as an example
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作者 Hongchao Qu Xiongbo Zheng +1 位作者 Lihong Yang Zhenya Song 《Acta Oceanologica Sinica》 2025年第6期165-177,共13页
In oceanic and atmospheric science,finer resolutions have become a prevailing trend in all aspects of development.For high-resolution fluid flow simulations,the computational costs of widely used numerical models incr... In oceanic and atmospheric science,finer resolutions have become a prevailing trend in all aspects of development.For high-resolution fluid flow simulations,the computational costs of widely used numerical models increase significantly with the resolution.Artificial intelligence methods have attracted increasing attention because of their high precision and fast computing speeds compared with traditional numerical model methods.The resolution-independent Fourier neural operator(FNO)presents a promising solution to the still challenging problem of high-resolution fluid flow simulations based on low-resolution data.Accordingly,we assess the potential of FNO for high-resolution fluid flow simulations using the vorticity equation as an example.We assess and compare the performance of FNO in multiple high-resolution tests varying the amounts of data and the evolution durations.When assessed with finer resolution data(even up to number of grid points with 1280×1280),the FNO model,trained at low resolution(number of grid points with 64×64)and with limited data,exhibits a stable overall error and good accuracy.Additionally,our work demonstrates that the FNO model takes less time than the traditional numerical method for high-resolution simulations.This suggests that FNO has the prospect of becoming a cost-effective and highly precise model for high-resolution simulations in the future.Moreover,FNO can make longer high-resolution predictions while training with less data by superimposing vorticity fields from previous time steps as input.A suitable initial learning rate can be set according to the frequency principle,and the time intervals of the dataset need to be adjusted according to the spatial resolution of the input when training the FNO model.Our findings can help optimize FNO for future fluid flow simulations. 展开更多
关键词 fourier neural operator high-resolution simulation fluid flow vorticity equation
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Masking quantum information in multipartite systems via Fourier and Hadamard matrices
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作者 Chen-Ming Bai Meng-Ya Wang +1 位作者 Su-Juan Zhang Lu Liu 《Communications in Theoretical Physics》 2025年第2期99-109,共11页
Quantum information masking(QIM)is a crucial technique for protecting quantum data from being accessed by local subsystems.In this paper,we introduce a novel method for achieving1-uniform QIM in multipartite systems u... Quantum information masking(QIM)is a crucial technique for protecting quantum data from being accessed by local subsystems.In this paper,we introduce a novel method for achieving1-uniform QIM in multipartite systems utilizing a Fourier matrix.We further extend this approach to construct an orthogonal array with the aid of a Hadamard matrix,which is a specific type of Fourier matrix.This allows us to explore the relationship between 2-uniform QIM and orthogonal arrays.Through this framework,we derive two distinct 2-uniform quantum states,enabling the 2-uniform masking of original information within multipartite systems.Furthermore,we prove that the maximum number of quantum bits required for achieving a2-uniformly masked state is 2^(n)-1,and the minimum is 2^(n-1)+3.Moreover,our scheme effectively demonstrates the rich quantum correlations between multipartite systems and has potential application value in quantum secret sharing. 展开更多
关键词 multipartite systems quantum information masking fourier matrix orthogonal arrays
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Pricing power option under NIG model using fast Fourier transform
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作者 LI Cui-xiang WANG Meng-na +1 位作者 LIU Hui-li LI Wen-han 《Applied Mathematics(A Journal of Chinese Universities)》 2025年第2期327-342,共16页
The aim of this paper is to price power option with its underlying asset price following exponential normal inverse gaussian(NIG)process.We first find the risk neutral equivalent martingale measure Q by Esscher transf... The aim of this paper is to price power option with its underlying asset price following exponential normal inverse gaussian(NIG)process.We first find the risk neutral equivalent martingale measure Q by Esscher transform.Then,using the Fourier transform and its inverse,we derive the analytical pricing formulas of power options which are expressed in the form of Fourier integral.In addition,the fast Fourier transform(FFT)algorithm is applied to calculate these pricing formulas.Finally,Shangzheng 50ETF options are chosen to test our results.Estimating the parameters in NIG process by maximum likelihood method,we show that the NIG prices are much closer to market prices than the Black-Scholes-Merton(BSM)ones. 展开更多
关键词 power option NIG process Esscher transform fourier transform FFT algorithm
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Multi-Scale Fusion Network Using Time-Division Fourier Transform for Rolling Bearing Fault Diagnosis
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作者 Ronghua Wang Shibao Sun +3 位作者 Pengcheng Zhao Xianglan Yang Xingjia Wei Changyang Hu 《Computers, Materials & Continua》 2025年第8期3519-3539,共21页
The capacity to diagnose faults in rolling bearings is of significant practical importance to ensure the normal operation of the equipment.Frequency-domain features can effectively enhance the identification of fault ... The capacity to diagnose faults in rolling bearings is of significant practical importance to ensure the normal operation of the equipment.Frequency-domain features can effectively enhance the identification of fault modes.However,existing methods often suffer from insufficient frequency-domain representation in practical applications,which greatly affects diagnostic performance.Therefore,this paper proposes a rolling bearing fault diagnosismethod based on aMulti-Scale FusionNetwork(MSFN)using the Time-Division Fourier Transform(TDFT).The method constructs multi-scale channels to extract time-domain and frequency-domain features of the signal in parallel.A multi-level,multi-scale filter-based approach is designed to extract frequency-domain features in a segmented manner.A cross-attention mechanism is introduced to facilitate the fusion of the extracted time-frequency domain features.The performance of the proposed method is validated using the CWRU and Ottawa datasets.The results show that the average accuracy of MSFN under complex noisy signals is 97.75%and 94.41%.The average accuracy under variable load conditions is 98.68%.This demonstrates its significant application potential compared to existing methods. 展开更多
关键词 Rolling bearing fault diagnosis time-division fourier transform cross-attention multi-scale feature fusion
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Fusion-based enhancement of multi-exposure Fourier ptychographic microscopy
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作者 Zhiping Wang Tianci Feng +2 位作者 Aiye Wang Jinghao Xu An Pan 《Advanced Photonics Nexus》 2025年第4期1-11,共11页
Fourier ptychographic microscopy(FPM)is an innovative computational microscopy approach that enables high-throughput imaging with high resolution,wide field of view,and quantitative phase imaging(QPI)by simultaneously... Fourier ptychographic microscopy(FPM)is an innovative computational microscopy approach that enables high-throughput imaging with high resolution,wide field of view,and quantitative phase imaging(QPI)by simultaneously capturing bright-field and dark-field images.However,effectively utilizing dark-field intensity images,including both normally exposed and overexposed data,which contain valuable high-angle illumination information,remains a complex challenge.Successfully extracting and applying this information could significantly enhance phase reconstruction,benefiting processes such as virtual staining and QPI imaging.To address this,we introduce a multi-exposure image fusion(MEIF)framework that optimizes dark-field information by incorporating it into the FPM preprocessing workflow.MEIF increases the data available for reconstruction without requiring changes to the optical setup.We evaluate the framework using both feature-domain and traditional FPM,demonstrating that it achieves substantial improvements in intensity resolution and phase information for biological samples that exceed the performance of conventional high dynamic range(HDR)methods.This image preprocessing-based information-maximization strategy fully leverages existing datasets and offers promising potential to drive advancements in fields such as microscopy,remote sensing,and crystallography. 展开更多
关键词 fourier ptychographic microscopy multi-exposure image fusion computational imaging feature-domain nonlinear image fusion
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Research on hybridβ-energy spectral analysis algorithm based on Fourier series function
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作者 Hao Fan Jun Qin +2 位作者 Bao-Hua Liu Tin-Xuan Yuan Wei Zhou 《Nuclear Science and Techniques》 2025年第6期176-186,共11页
With the rapid development of the nuclear power industry on a global scale,the discharge of radioactive e uents from nuclear power plants and their impact on the environment have become important issues in radioactive... With the rapid development of the nuclear power industry on a global scale,the discharge of radioactive e uents from nuclear power plants and their impact on the environment have become important issues in radioactive waste management,radiation protection,and environmental impact assessments.-detection of nuclides requires tedious processes,such as waiting for the radioactive balance of the sample and pretreatment separation,and there is an urgent need for a method specifically designed for mixing rapid energy spectrum measurement method for nuclide samples.The analysis of hybrid-energy spectrum is proposed in this study as a new algorithm,which takes advantage of the spectral analysis of-logarithmic energy spectrum and fitting ability of Fourier series.The logarithmic energy spectrum is obtained by logarithmic conversion of the hybrid linear energy spectrum.The Fourier fitting interpolation method is used to fit the logarithmic energy spectrum numerically.Next,the interpolation points for the‘e ective high-energy window’and‘e ective low-energy window’corresponding to the highest E_(m)nuclide in the hybrid logarithmic fitted energy spectrum are set,and spline interpolation is performed three times to obtain the logarithmic fitted energy spectrum of the highest E_(m)nuclide.Finally,the logarithmic fitted spectrum of the highest E_(m)nuclide is subtracted from the hybrid logarithmic fitted spectrum to obtain a logarithmic fitted spectrum comprised of the remaining lower E_(m)nuclides.The aforementioned process is iterated in a loop to resolve the logarithmic spectra of each nuclide in the original hybrid logarithmic spectra.Then,the radioactivity of E_(m)nuclides to be measured is calculated.In the experimental tests,^(14)C,^(90)Sr,and ^(90)Y spectra,which are obtained using the Fourier fitting interpolation method are compared with the original simulated ^(14)C,^(90)Sr,and ^(90)Y spectra of GEANT4.The measured liquid scintillator data of ^(90)Sr∕^(90)Y sample source and simulated data from GEANT4 are then analyzed.Analysis of the experimental results indicates that the Fourier fitting interpolation method accurately solves ^(14)C,^(90)Sr,and ^(90)Y energy spectra,which is in good agreement with the original GEANT4 simulation.The error in ^(90)Y activity,calculated using the actual detection e ciency,is less than 10%and less than 5%when using the simulated full-spectrum detection e ciency,satisfying the experimental expectations. 展开更多
关键词 Nuclear power effluents Hybridenergy spectrum fourier series Cubic spline interpolation Activity calculation
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