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Adaptive split-step Fourier method for simulating ultrashort laser pulse propagation in photonic crystal fibres 被引量:3
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作者 李曙光 邢光龙 +5 位作者 周桂耀 韩颖 侯蓝田 胡明列 栗岩锋 王清月 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第2期437-443,共7页
In this paper, the generalized nonlinear Schrodinger equation (GNLSE) is solved by an adaptive split-step Fourier method (ASSFM). It is found that ASSFM must be used to solve GNLSE to ensure precision when the sol... In this paper, the generalized nonlinear Schrodinger equation (GNLSE) is solved by an adaptive split-step Fourier method (ASSFM). It is found that ASSFM must be used to solve GNLSE to ensure precision when the soliton selffrequency shift is remarkable and the photonic crystal fibre (PCF) parameters vary with the frequency considerably. The precision of numerical simulation by using ASSFM is higher than that by using split-step Fourier method in the process of laser pulse propagation in PCFs due to the fact that the variation of fibre parameters with the peak frequency in the pulse spectrum can be taken into account fully. 展开更多
关键词 photonic crystal fibre ultrashort laser pulse propagation adaptive split-step fourier method
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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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阻尼eKdV-Burgers方程的共形广义多辛Fourier拟谱算法
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作者 李骞 王桂霞 王一辰 《应用数学和力学》 北大核心 2025年第11期1464-1479,共16页
基于Hamilton共形广义多辛理论,研究一类阻尼eKdV-Burgers方程的共形广义多辛Fourier拟谱格式的保结构算法.首先,通过引入中间变量,将方程转化为满足局部守恒的共形广义多辛Hamilton系统,并利用Strang分裂方法,将其分裂为守恒子系统和... 基于Hamilton共形广义多辛理论,研究一类阻尼eKdV-Burgers方程的共形广义多辛Fourier拟谱格式的保结构算法.首先,通过引入中间变量,将方程转化为满足局部守恒的共形广义多辛Hamilton系统,并利用Strang分裂方法,将其分裂为守恒子系统和耗散子系统.进一步,空间上利用Fourier拟谱方法,时间上利用隐中点方法,对该系统进行离散,得到共形广义多辛Fourier拟谱格式,在周期边界条件下,该格式满足全局共形质量守恒律和动量守恒律.数值实例表明该算法是有效的,能够保持系统质量和动量衰减特性. 展开更多
关键词 耗散项 浅水效应 eKdV-Burgers方程 共形广义多辛 fourier拟谱方法 Strang分裂
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结合VMD和Fourier导数的非线性系统识别方法
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作者 田如月 黄天立 唐蕾 《振动与冲击》 北大核心 2025年第23期130-140,共11页
在处理多分量非线性信号时,信号受到噪声干扰使得传统分解方法难以自适应地分离出有效信号分量,同时,传统时频方法在识别瞬时频率时受限于谱图的时频分辨率精度和脊线算法效率等问题,传统时频分析方法识别多自由度非线性系统的瞬时频率... 在处理多分量非线性信号时,信号受到噪声干扰使得传统分解方法难以自适应地分离出有效信号分量,同时,传统时频方法在识别瞬时频率时受限于谱图的时频分辨率精度和脊线算法效率等问题,传统时频分析方法识别多自由度非线性系统的瞬时频率效果不佳。为此,提出了一种结合变分模态分解(variational mode decomposition,VMD)和Fourier导数的多自由度非线性系统识别方法。首先采用信号的傅里叶频谱确定分解模态数K,并采用VMD将多分量信号分解为K个模态分量,提取有效信号分量;然后基于Hilbert变换构造各模态分量的解析复信号;最后基于Fourier导数选取信号相邻两个时间点进行插值、求极限运算求解各分量的瞬时频率,从而识别非线性系统的动态特性。数值模拟无阻尼和有阻尼多分量信号,水平加速度简谐激励和地震激励下含Bouc-Wen滞回系统的两层剪切型结构响应,带阻尼器的三层钢框架结构振动台试验,验证了所提方法的准确性和适用性。数值模拟结果表明,相较于短时傅里叶变换和Hilbert变换,提出的结合VMD和Fourier导数方法的非线性系统瞬时频率识别精度优于短时傅里叶变换和希尔伯特变换方法;振动台试验结果表明,所提方法能准确识别地震激励下非线性结构的瞬时频率。 展开更多
关键词 非线性系统识别 多自由度 fourier导数 变分模态分解(VMD) 瞬时频率
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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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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 Convergence Analyzed by Stochastic C-Stability and Stochastic B-Consistency of Split-Step Theta Method for the Stochastic Differential Equations
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作者 Ping GUO Ye WANG Yining GAO 《Journal of Mathematical Research with Applications》 2025年第3期362-376,共15页
In this paper,the convergence of the split-step theta method for stochastic differential equations is analyzed using stochastic C-stability and stochastic B-consistency.The fact that the numerical scheme,which is both... In this paper,the convergence of the split-step theta method for stochastic differential equations is analyzed using stochastic C-stability and stochastic B-consistency.The fact that the numerical scheme,which is both stochastically C-stable and stochastically B-consistent,is convergent has been proved in a previous paper.In order to analyze the convergence of the split-step theta method(θ∈[1/2,1]),the stochastic C-stability and stochastic B-consistency under the condition of global monotonicity have been researched,and the rate of convergence 1/2 has been explored in this paper.It can be seen that the convergence does not require the drift function should satisfy the linear growth condition whenθ=1/2 Furthermore,the rate of the convergence of the split-step scheme for stochastic differential equations with additive noise has been researched and found to be 1.Finally,an example is given to illustrate the convergence with the theoretical results. 展开更多
关键词 stochastic differential equation stochastic C-stability stochastic B-consistency CONVERGENCE split-step theta method
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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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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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Physics field super-resolution reconstruction via enhanced diffusion model and fourier neural operator
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作者 Yanan Guo Junqiang Song +2 位作者 Xiaoqun Cao Chuanfeng Zhao Hongze Leng 《Theoretical & Applied Mechanics Letters》 2025年第5期498-507,共10页
With the growing demand for high-precision flow field simulations in computational science and engineering,the super-resolution reconstruction of physical fields has attracted considerable research interest.However,tr... With the growing demand for high-precision flow field simulations in computational science and engineering,the super-resolution reconstruction of physical fields has attracted considerable research interest.However,tradi-tional numerical methods often entail high computational costs,involve complex data processing,and struggle to capture fine-scale high-frequency details.To address these challenges,we propose an innovative super-resolution reconstruction framework that integrates a Fourier neural operator(FNO)with an enhanced diffusion model.The framework employs an adaptively weighted FNO to process low-resolution flow field inputs,effectively capturing global dependencies and high-frequency features.Furthermore,a residual-guided diffusion model is introduced to further improve reconstruction performance.This model uses a Markov chain for noise injection in phys-ical fields and integrates a reverse denoising procedure,efficiently solved by an adaptive time-step ordinary differential equation solver,thereby ensuring both stability and computational efficiency.Experimental results demonstrate that the proposed framework significantly outperforms existing methods in terms of accuracy and efficiency,offering a promising solution for fine-grained data reconstruction in scientific simulations. 展开更多
关键词 fourier neural operator Diffusion model Super-resolution reconstruction Flow field simulation Scientific computing
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