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Existence of Solution to a Class of Elliptic Equations with Lower Order Terms and Variable Exponents
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作者 Zhongqing LI 《Journal of Mathematical Research with Applications》 CSCD 2024年第6期795-806,共12页
We study a class of nonlinear elliptic equations with nonstandard growth condition.The main feature is that two lower order terms,a non-coercive divergence term divΦ(x,u)and a gradient term H(x,u,▽u)with no growth r... We study a class of nonlinear elliptic equations with nonstandard growth condition.The main feature is that two lower order terms,a non-coercive divergence term divΦ(x,u)and a gradient term H(x,u,▽u)with no growth restriction on u,appear simultaneously in the variable exponents setting.These characteristics prevent us from directly obtaining the existence of solutions by employing the classical theory on existence results.By choosing some appropriate test functions in the perturbed problem,some a priori estimates are obtained under the variable exponent framework.Based on these estimates,we prove the almost everywhere convergence of the gradient sequence{▽u^(ε)}_(ε),which helps to pass to the limit to find a weak solution. 展开更多
关键词 elliptic equations nonstandard growth condition lower order terms weak solutions
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The Lower Orders of Dirichlet and Random Dirichlet Series 被引量:7
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作者 Yu Jiarong (Department of Mathematics,Wuhan University,Wuhan 430072,China) 《Wuhan University Journal of Natural Sciences》 CAS 1996年第1期1-8,共8页
The formulas of the lower orders of Dirichlet series are given by means of the exponents and the convex regularized sequences of the logarithms and the convex regularized sequences of the logarithms of the moduli of t... The formulas of the lower orders of Dirichlet series are given by means of the exponents and the convex regularized sequences of the logarithms and the convex regularized sequences of the logarithms of the moduli of the coefficients. Corresponding results are obtained for some random Dirichlet series. 展开更多
关键词 Dirichlet series random Dirichlet series lower order convex regularization
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THE LOWER ORDER AND LINEAR ORDER OF MULTIPLE DIRICHLET SERIES 被引量:4
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作者 梁美丽 霍颖莹 《Acta Mathematica Scientia》 SCIE CSCD 2017年第1期131-138,共8页
The article investigates the growth of multiple Dirichlet series.The lower order and the linear order of n-tuple Dirichlet series in Cn are defined and some relations between them and the coefficients and exponents of... The article investigates the growth of multiple Dirichlet series.The lower order and the linear order of n-tuple Dirichlet series in Cn are defined and some relations between them and the coefficients and exponents of n-tuple Dirichlet series are obtained. 展开更多
关键词 multiple Dirichlet series lower order linear order
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Theoretical Explanation for Lower Order Harmonic Resonance Phenomenon of Three-Ring Gear Transmissions 被引量:2
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作者 杨建明 张策 +1 位作者 林忠钦 陈关龙 《Journal of Shanghai Jiaotong university(Science)》 EI 2003年第1期71-74,共4页
Dynamic investigations revealed that lower order harmonic resonance phenomenon exists in the three ring gear transmission. That is, when the input speed is close to 1/3, 1/6, 1/9,…, 1/3 n of the primary natural frequ... Dynamic investigations revealed that lower order harmonic resonance phenomenon exists in the three ring gear transmission. That is, when the input speed is close to 1/3, 1/6, 1/9,…, 1/3 n of the primary natural frequency of the transmission, the loads on the bearings and gears are especially high. This paper explained this phenomenon from the viewpoint of parametric resonance in terms of perturbation technique. A conclusion was drawn that the basic reason for this phenomenon is the primary resonance caused by forcing excitation and parametric resonance caused by parametric change. 展开更多
关键词 three ring gear transmission lower order resonance phenomenon natural frequency primary resonance parametric resonance
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THE GENERALIZED LOWER ORDER OF DIRICHLET SERIES 被引量:1
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作者 Qingyuan CHEN Yingying HUO 《Acta Mathematica Scientia》 SCIE CSCD 2020年第4期1141-1151,共11页
In this paper,we study the generalized lower order of entire functions defined by Dirichlet series.By constructing the Newton polygon based on Knopp-Kojima’s formula,we obtain a relation between the coefficients of t... In this paper,we study the generalized lower order of entire functions defined by Dirichlet series.By constructing the Newton polygon based on Knopp-Kojima’s formula,we obtain a relation between the coefficients of the Dirichlet series and its generalized lower order. 展开更多
关键词 Dirichlet series Knopp-Kojima method Newton polygon generalized lower order
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The Lower Order and Type of Solutions of Second Order Differential Equation
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作者 ZHANG Shao-hua WU Zhao-jun SUN Dao-chun 《Chinese Quarterly Journal of Mathematics》 CSCD 2014年第1期14-21,共8页
The main purpose of this paper is to study the lower order and type of second order differential equation w"(z)-A(z)w=0,where A(z)is a polynomial.In the case of A(z)=a_dz^d,the authors prove that the lower order ... The main purpose of this paper is to study the lower order and type of second order differential equation w"(z)-A(z)w=0,where A(z)is a polynomial.In the case of A(z)=a_dz^d,the authors prove that the lower order and the type of all non-trivial solutions w of w"(z)-A(z)w=0 are equal to(d+2)/2 and(2(|a_d|)^(1/2))/(d+2)respectively.In the case of A(z)=a_dz^d+a_(d-1)z^(d-1)+…a_1z+a_0,a_d>0,a_(d-1)>0,…,a_1≥0,a_0≥0,the authors prove that the lower order of all non-trivial solutions w of w"(z)-A(z)w=0 is(d+2)/2. 展开更多
关键词 TYPE order lower order differential equation
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Construction of Split-Plot Designs with General Minimum Lower Order Confounding
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作者 Kexin Li Beichen Han Zhenzhen Niu 《Open Journal of Applied Sciences》 CAS 2023年第3期261-274,共14页
Fractional factorial split-plot design has been widely used in many fields due to its advantage of saving experimental cost. The general minimum lower order confounding criterion is usually used as one of the attracti... Fractional factorial split-plot design has been widely used in many fields due to its advantage of saving experimental cost. The general minimum lower order confounding criterion is usually used as one of the attractive design criterion for selecting fractional factorial split-plot design. In this paper, we are interested in the theoretical construction methods of the optimal fractional factorial split-plot designs under the general minimum lower order confounding criterion. We present the theoretical construction methods of optimal fractional factorial split-plot designs under general minimum lower order confounding criterion under several conditions. 展开更多
关键词 Fractional Factorial Design General Minimum lower order Confounding Criterion Split-Plot Design
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DOA Estimation Based on Sparse Representation of the Fractional Lower Order Statistics in Impulsive Noise 被引量:10
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作者 Sen Li Rongxi He +1 位作者 Bin Lin Fei Sun 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2018年第4期860-868,共9页
This paper is mainly to deal with the problem of direction of arrival(DOA) estimations of multiple narrow-band sources impinging on a uniform linear array under impulsive noise environments. By modeling the impulsive ... This paper is mainly to deal with the problem of direction of arrival(DOA) estimations of multiple narrow-band sources impinging on a uniform linear array under impulsive noise environments. By modeling the impulsive noise as α-stable distribution, new methods which combine the sparse signal representation technique and fractional lower order statistics theory are proposed. In the new algorithms, the fractional lower order statistics vectors of the array output signal are sparsely represented on an overcomplete basis and the DOAs can be effectively estimated by searching the sparsest coefficients. To enhance the robustness performance of the proposed algorithms,the improved algorithms are advanced by eliminating the fractional lower order statistics of the noise from the fractional lower order statistics vector of the array output through a linear transformation. Simulation results have shown the effectiveness of the proposed methods for a wide range of highly impulsive environments. 展开更多
关键词 α-stable distribution direction of arrival(DOA) fractional lower-order statistics impulsive noise sparse representation
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New blind estimation method of evoked potentials based on minimum dispersion criterion and fractional lower order statistics
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作者 Daifeng Zha 《Journal of Biomedical Science and Engineering》 2008年第2期91-97,共7页
Evoked potentials (EPs) have been widely used to quantify neurological system properties. Tra-ditional EP analysis methods are developed under the condition that the background noises in EP are Gaussian distributed. A... Evoked potentials (EPs) have been widely used to quantify neurological system properties. Tra-ditional EP analysis methods are developed under the condition that the background noises in EP are Gaussian distributed. Alpha stable distribution, a generalization of Gaussian, is better for modeling impulsive noises than Gaussian distribution in biomedical signal proc-essing. Conventional blind separation and es-timation method of evoked potentials is based on second order statistics or high order Statis-tics. Conventional blind separation and estima-tion method of evoked potentials is based on second order statistics (SOS). In this paper, we propose a new algorithm based on minimum dispersion criterion and fractional lower order statistics. The simulation experiments show that the proposed new algorithm is more robust than the conventional algorithm. 展开更多
关键词 EVOKED POTENTIALS (EPs) Alpha stable distribution BLIND source separation Minimum dispersion (MD) FRACTIONAL lower order statistics (FLOS)
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Some Results on Entire Functions of Finite Lower Order 被引量:7
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作者 Wu Shengjian Department of Mathematics Peking University Beijing, 100871 China 《Acta Mathematica Sinica,English Series》 SCIE CSCD 1994年第2期168-178,共11页
Let f(z) be an entire function of order λ and of finite lower order μ. If the zeros of f(z) accumulate in the vicinity of a finite number of rays, then (a) λ is finite; (b) for every arbitrary number k<... Let f(z) be an entire function of order λ and of finite lower order μ. If the zeros of f(z) accumulate in the vicinity of a finite number of rays, then (a) λ is finite; (b) for every arbitrary number k<sub>1</sub>】1, there exists k<sub>2</sub>】1 such that T(k<sub>1</sub>r, f)≤k<sub>2</sub>T(r, f) for all r≥r<sub>0</sub>. Applying the above results, we prove that if f(z) is extremal for Yang’s inequality p=g/2, then (c) every deficient value of f(z) is also its asymptotic value; (d) every asymptotic value of f(z) is also its deficient value; (e) λ=μ; (f) ∑a≠∞δ5(a, f)≤1-k(μ). 展开更多
关键词 Some Results on Entire Functions of Finite lower order
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A theory on constructing blocked two-level designs with general minimum lower order confounding 被引量:1
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作者 Yuna ZHAO Shengli ZHAO Min-Qian LIU 《Frontiers of Mathematics in China》 SCIE CSCD 2016年第1期207-235,共29页
Completely random allocation of the treatment combinations to the experimental units is appropriate only if the experimental units are homogeneous. Such homogeneity may not always be guaranteed when the size of the ex... Completely random allocation of the treatment combinations to the experimental units is appropriate only if the experimental units are homogeneous. Such homogeneity may not always be guaranteed when the size of the experiment is relatively large. Suitably partitioning inhomogeneous units into homogeneous groups, known as blocks, is a practical design strategy. How to partition the experimental units for a given design is an important issue. The blocked general minimum lower order confounding is a new criterion for selecting blocked designs. With the help of doubling theory and second order saturated design, we present a theory on constructing optimal blocked designs under the blocked general minimum lower order confounding criterion. 展开更多
关键词 Aliased effect-number pattern general minimum lower orderconfounding second order saturated design Yates order
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Lower Approximation Reduction in Ordered Information System with Fuzzy Decision 被引量:1
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作者 Xiaoyan Zhang Weihua Xu 《Applied Mathematics》 2011年第7期918-921,共4页
Attribute reduction is one of the most important problems in rough set theory. This paper introduces the concept of lower approximation reduction in ordered information systems with fuzzy decision. Moreover, the judgm... Attribute reduction is one of the most important problems in rough set theory. This paper introduces the concept of lower approximation reduction in ordered information systems with fuzzy decision. Moreover, the judgment theorem and discernable matrix are obtained, in which case an approach to attribute reduction in ordered information system with fuzzy decision is constructed. As an application of lower approximation reduction, some examples are applied to examine the validity of works obtained in our works.. 展开更多
关键词 Fuzzy DECISION lower APPROXIMATION REDUCTION orderED Information Systems ROUGH Set
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SαS分布噪声下基于特征值调和平均的稳健频谱感知算法
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作者 杨喜 周睿勇 +4 位作者 雷可君 张耿 张银行 曹秀英 王仁玮 《湖南大学学报(自然科学版)》 北大核心 2025年第8期172-182,共11页
针对SαS分布噪声提出了一种基于分数低阶预处理与特征值调和平均检测相结合的频谱感知算法,该算法以分数低阶预处理接收信号样本协方差矩阵的最大特征值与特征值调和平均之差与最小特征值之比(DMHMM)作为感知判决量.该算法在预处理阶... 针对SαS分布噪声提出了一种基于分数低阶预处理与特征值调和平均检测相结合的频谱感知算法,该算法以分数低阶预处理接收信号样本协方差矩阵的最大特征值与特征值调和平均之差与最小特征值之比(DMHMM)作为感知判决量.该算法在预处理阶段通过分数低阶操作降低SαS分布噪声非高斯特性的影响,在检测阶段利用极值特征值与特征值调和平均设计检测判决量,检测过程避免了对噪声参数的依赖,适应范围广.在此基础上,基于Wishart矩阵特征值几何平均的矩理论,以及高维随机矩阵中最大和最小特征值渐近分布理论,针对DMHMM频谱感知算法提出了一种有效的理论判决门限计算方法,在降低理论门限计算复杂度的同时,提高了非渐近条件下SαS分布噪声中主用户信号检测结果的可靠性.Monte-Carlo仿真结果表明,所提DMHMM频谱感知算法可以获得比半盲DMGM算法更为可靠的检测判决结果,且在检测阶段无需SαS分布噪声的相关参数;由于综合利用了分数低阶预处理后取样协方差矩阵的极值特征值以及特征值调和平均信息,能够更好地反映主用户信号的变化,使得新算法具有比MME和CHME算法更优的检测效果. 展开更多
关键词 频谱感知 SαS分布噪声 分数低阶矩 特征值分布 调和平均
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基于二次分数低阶协方差的双阵元接收阵列超声波风矢量测量
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作者 刘小松 任玮 +2 位作者 单泽彪 张旭 柳鹏 《仪表技术与传感器》 北大核心 2025年第5期107-111,共5页
针对强脉冲噪声背景下超声波风速风向测量性能下降、抗噪声能力不足等问题,提出了一种基于二次分数低阶协方差的双阵元接收阵列超声波风矢量测量方法。所提方法采用一种双阵元接收阵列结构,该结构由单个发射传感器搭配2个接收传感器组成... 针对强脉冲噪声背景下超声波风速风向测量性能下降、抗噪声能力不足等问题,提出了一种基于二次分数低阶协方差的双阵元接收阵列超声波风矢量测量方法。所提方法采用一种双阵元接收阵列结构,该结构由单个发射传感器搭配2个接收传感器组成,在此结构基础上应用二次分数低阶协方差算法对超声波传播时间进行估测,并计算得出实际的风速风向。通过模拟仿真实验对所提方法进行了有效性验证,实验结果表明:所提方法对脉冲噪声具有显著的抑制效果,风速测量误差为0.27 m/s,风向角测量误差为2.7°,达到了超声波测风方法的测量标准。 展开更多
关键词 风速风向测量 脉冲噪声 二次分数低阶协方差 双阵元阵列结构
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4种树苗生长的干旱胁迫响应取决于低序级根性状
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作者 杨智慧 韦柳端 +5 位作者 于淼 董天心 张星宇 张新娜 马冰倩 徐程扬 《林业科学》 北大核心 2025年第9期81-89,共9页
【目的】分析1~3序级根系性状的变化及其对生长在不同土壤干旱胁迫程度中树苗的苗高、地径相对生长量的影响,揭示生物学特性差异较大的树种个体生长对干旱胁迫的1~3序级根系响应机制。【方法】选用生长速度、生态习性差异较大的4个树种... 【目的】分析1~3序级根系性状的变化及其对生长在不同土壤干旱胁迫程度中树苗的苗高、地径相对生长量的影响,揭示生物学特性差异较大的树种个体生长对干旱胁迫的1~3序级根系响应机制。【方法】选用生长速度、生态习性差异较大的4个树种(元宝枫、山桃、栓皮栎和栾树)的1年生实生苗,通过土壤水分梯度控制试验,测量1~5序级根系的平均直径(RD)、比根长(SRL)、比根表面积(SRA)和根组织密度(RTD),利用相对相互作用指数来评价干旱强度对苗木生长和根系性状的相对影响程度,分析了干旱胁迫对苗木的高相对生长量、地径相对生长量的影响,研究了低序级根系RD、SRL、SRA及RTD对高相对生长量、地径相对生长量的影响机制。【结果】土壤干旱对4个树种幼苗的高相对生长量、地径相对生长量均产生极显著的影响(P<0.001),并且这种影响的种间差异极显著(P<0.001),种间差异远大于干旱梯度间差异:严重干旱使元宝枫和栾树幼苗的高、地径生长同步降低,山桃幼苗的高、地径生长在干旱环境中向细、高方向发展,而栓皮栎幼苗的高、地径同步提高。苗木生长差异格局显著受到低序级(1~3序级)根系的RD、SRL、SRA及RTD变化的影响,与高序级(4和5序级)根系性状间相关性较低;幼苗的高相对生长量、地径相对生长量与低序级根的RD、SRA显著正相关(P<0.05),与低序级根的SRL、RTD显著负相关(P<0.05),即苗木的土壤资源获取策略变化在一定程度上决定了苗木地上生长。元宝枫和栾树幼苗的高、地径相对生长量较高,并伴随着较高的低序级根系的RD和SRA,即以资源获取对策适应干旱环境;而山桃和栓皮栎幼苗的高、地径相对生长量较低,并伴随着较高的SRL和RTD,即以保守策略适应干旱环境。【结论】土壤干旱对树木幼苗的高和地径生长的影响与低序级根系性状变化密切相关,且这种关系存在树种差异。在干旱土壤环境中,元宝枫和栾树幼苗依赖大量细根获取土壤资源,属于快速投资收益型;而山桃和栓皮栎的根系直径较大,属于慢速投资收益型。4个树种在土壤干旱环境中吸收根的性状总体上向避旱方向发展。 展开更多
关键词 低序级根 根系功能性状 土壤干旱 树苗相对生长量 树种间差异
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二维下腔室稳态流场降阶模型开发
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作者 商贺 彭敏俊 +2 位作者 夏庚磊 张世琦 朱世杰 《原子能科学技术》 北大核心 2025年第10期2319-2331,共13页
计算流体力学(CFD)程序基于三维Navier-Stokes(N-S)方程组,可实现三维尺度的模拟。但CFD模拟通常需要较长的计算时间,难以实现快速计算,限制了其应用场景。本文采用本征正交分解(POD)方法和稀疏网格理论,构建了二维压力容器下腔室稳态... 计算流体力学(CFD)程序基于三维Navier-Stokes(N-S)方程组,可实现三维尺度的模拟。但CFD模拟通常需要较长的计算时间,难以实现快速计算,限制了其应用场景。本文采用本征正交分解(POD)方法和稀疏网格理论,构建了二维压力容器下腔室稳态流场的非侵入式降阶模型。降阶模型的输入为下腔室两个入口的冷却剂质量流量,输出为下腔室速度场分布。基于稀疏网格理论,通过运行全阶CFD下腔室模型生成快照矩阵,并拟合POD系数与降阶模型输入参数之间的映射关系。在测试集上对构建的降阶模型进行测试,结果表明:所构建的降阶模型可以快速得到不同入口流量下的流场分布数据,且精度满足仿真要求。由于降阶模型仅涉及矩阵代数运算,其计算速度远高于全阶CFD模型,拓宽了CFD的应用范围,有望应用于多尺度耦合、数字孪生等对计算速度要求较高的场景。 展开更多
关键词 POD 稀疏网格 降阶模型 下腔室
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Growth of Meromorphic Solutions of Complex Linear Differential-Difference Equations with Coefficients Having the Same Order 被引量:1
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作者 Shunzhou WU Xiumin ZHENG 《Journal of Mathematical Research with Applications》 CSCD 2014年第6期683-695,共13页
The main purpose of this paper is to study the growth of meromorphic solutions of complex linear differential-difference equations L(z, f) =n∑i=0m∑j=0Aij(z)f^(j)(z + ci) = 0 or F(z)with entire or meromorp... The main purpose of this paper is to study the growth of meromorphic solutions of complex linear differential-difference equations L(z, f) =n∑i=0m∑j=0Aij(z)f^(j)(z + ci) = 0 or F(z)with entire or meromorphic coefficients, and ci, i = 0,..., n being distinct complex numbers,where there is only one dominant coefficient. 展开更多
关键词 linear differential-difference equation meromorphic solution order lower order
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一类具低阶项的拟线性椭圆方程弱解的存在性
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作者 李仲庆 《吉林大学学报(理学版)》 北大核心 2025年第3期685-690,共6页
用非线性偏微分方程中的弱收敛方法,证明一类具梯度项和零阶项的拟线性椭圆方程解的存在性.该方程的主要特点是梯度项的系数函数b∈L N(Ω),但不要求其范数‖b‖N,Ω充分小.首先,通过对有界区域Ω做分割,将解序列{u}0<<1分解成一... 用非线性偏微分方程中的弱收敛方法,证明一类具梯度项和零阶项的拟线性椭圆方程解的存在性.该方程的主要特点是梯度项的系数函数b∈L N(Ω),但不要求其范数‖b‖N,Ω充分小.首先,通过对有界区域Ω做分割,将解序列{u}0<<1分解成一些子函数之和,限定在小的子区域上对子函数做能量估计.其次,通过迭代技术得到{u}0<<1在W^(1,p)_(0)(Ω)上的能量估计.最后,借助Boccardo-Murat技术,证明梯度解序列{u}0<<1的几乎处处收敛性,并基于该收敛性确定方程非线性项的收敛元. 展开更多
关键词 椭圆方程 拟线性 低阶项
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基于分数低阶极坐标图和视觉变换网络的调制识别方法
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作者 孟水仙 朱明波 +3 位作者 刘喆 周嘉晨 尚睿 栾声扬 《无线电工程》 2025年第6期1215-1222,共8页
自动调制识别(Automatic Modulation Classification,AMC)是通信系统中信号检测与解调的关键环节,发挥着重要作用。现有方法通常假设噪声服从高斯分布,但实际环境中含有尖锐峰值的脉冲性噪声普遍存在,导致传统方法因噪声模型失配而性能... 自动调制识别(Automatic Modulation Classification,AMC)是通信系统中信号检测与解调的关键环节,发挥着重要作用。现有方法通常假设噪声服从高斯分布,但实际环境中含有尖锐峰值的脉冲性噪声普遍存在,导致传统方法因噪声模型失配而性能下降。为解决该问题,提出了一种新的AMC方法。该方法以新提出的分数低阶极坐标图(Fractional Lower-Order Polar Plane,FLOPOLA)作为输入特征,以新设计的视觉变换(Vision Transformer,ViT)网络作为轻量化的特征提取器和分类器。蒙特卡洛实验结果表明,在不同的脉冲性噪声条件下,所提出的方法能够取得较高的识别准确率。进一步说明FLOPOLA能够较好地抑制脉冲性噪声中的野点,ViT能够较好地实现特征的提取和分类。所提出的方法能较好地解决脉冲性噪声条件下的AMC问题,具备在高准确率且低功耗场景中的潜在应用价值。 展开更多
关键词 ALPHA稳定分布 自动调制识别 分数低阶统计量 极坐标图
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具有平流项和低阶项的椭圆方程很弱解的局部高阶可积性
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作者 徐秀娟 沈毅 佟玉霞 《中南民族大学学报(自然科学版)》 2025年第2期283-288,共6页
在可测条件下,选取适当的截断函数并利用Hodge分解定理,得到具有平流项和低阶项的非齐次A-调和方程很弱解的局部高阶可积性,从而推广了相关文献中的有关结果.
关键词 平流项 低阶项 很弱解 HODGE分解 高阶可积性
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