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Analytic Functions Related to a Balloon-Shaped Domain 与气球形域相关的解析函数
IF 5.4 2区 数学 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2023-12-05 DOI: 10.3390/fractalfract7120865
Adeel Ahmad, Jianhua Gong, Isra Al-shbeil, A. Rasheed, Asad Ali, Saqib Hussain
One of the fundamental parts of Geometric Function Theory is the study of analytic functions in different domains with critical geometrical interpretations. This article defines a new generalized domain obtained based on the quotient of two analytic functions. We derive various properties of the new class of normalized analytic functions X defined in the new domain, including the sharp estimates for the coefficients a2,a3, and a4, and for three second-order and third-order Hankel determinants, H2,1X,H2,2X, and H3,1X. The optimality of each obtained estimate is given as well.
几何函数理论的一个基本部分是研究具有关键几何解释的不同域的解析函数。本文定义了基于两个解析函数的商得到的一个新的广义定义域。我们推导了在新定域上定义的新一类归一化解析函数X的各种性质,包括系数a2,a3和a4的锐估计,以及三个二阶和三阶Hankel行列式H2,1X,H2,2X和H3,1X的锐估计。并给出了得到的每个估计的最优性。
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引用次数: 0
Convergence Rate of the Diffused Split-Step Truncated Euler–Maruyama Method for Stochastic Pantograph Models with Lévy Leaps 有列维跃迁的随机受电弓模型的扩散分步截断欧拉-Maruyama 方法的收敛率
IF 5.4 2区 数学 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2023-12-04 DOI: 10.3390/fractalfract7120861
Amr Abou-Senna, Ghada AlNemer, Yongchun Zhou, Boping Tian
This paper studies the stochastic pantograph model, which is considered a subcategory of stochastic delay differential equations. A more general jump process, which is called the Lévy process, is added to the model for better performance and modeling situations, having sudden changes and extreme events such as market crashes in finance. By utilizing the truncation technique, we propose the diffused split-step truncated Euler–Maruyama method, which is considered as an explicit scheme, and apply it to the addressed model. By applying the Khasminskii-type condition, the convergence rate of the proposed scheme is attained in Lp(p≥2) sense where the non-jump coefficients grow super-linearly while the jump coefficient acts linearly. Also, the rate of convergence of the proposed scheme in Lp(0
本文研究了随机受电弓模型,该模型被认为是随机时滞微分方程的一个子类。一个更一般的跳跃过程,被称为lsamvy过程,被添加到模型中,以获得更好的性能和建模情况,具有突然变化和极端事件,如金融市场崩溃。利用截断技术,我们提出了作为显式格式的扩散分步截断Euler-Maruyama方法,并将其应用于所寻址模型。利用khasminskii型条件,得到了非跳跃系数超线性增长而跳跃系数线性增长的Lp(p≥2)意义下的收敛速度。此外,还讨论了在Lp(0
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引用次数: 0
Adaptive Fuzzy Fault-Tolerant Control of Uncertain Fractional-Order Nonlinear Systems with Sensor and Actuator Faults 具有传感器和执行器故障的不确定分数阶非线性系统的自适应模糊容错控制
IF 5.4 2区 数学 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2023-12-04 DOI: 10.3390/fractalfract7120862
Ke Sun, Zhiyao Ma, Guowei Dong, Ping Gong
In this work, an adaptive fuzzy backstepping fault-tolerant control (FTC) issue is tackled for uncertain fractional-order (FO) nonlinear systems with sensor and actuator faults. A fuzzy logic system is exploited to manage unknown nonlinearity. In addition, a novel FO nonlinear filter-based dynamic surface control (DSC) method is constructed, effectively avoiding the inherent complexity explosion problem in the backstepping recursive process, and in the light of the construction of auxiliary functions, compensating the coupling term introduced by faults. On account of certain assumptions, the stability criterion of the FO Lyapunov function is applied to guarantee the stability of the closed-loop system. Finally, the simulation example verifies the validity of the presented control strategy.
本文研究了具有传感器和执行器故障的不确定分数阶非线性系统的自适应模糊反步容错控制问题。利用模糊逻辑系统来处理未知的非线性。此外,构造了一种新的基于非线性滤波的动态面控制方法,有效地避免了逆推递推过程中固有的复杂性爆炸问题,并根据辅助函数的构造,补偿了故障引入的耦合项。在一定的假设条件下,利用Lyapunov函数的稳定性判据来保证闭环系统的稳定性。最后,通过仿真实例验证了所提控制策略的有效性。
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引用次数: 0
Maclaurin-Type Integral Inequalities for GA-Convex Functions Involving Confluent Hypergeometric Function via Hadamard Fractional Integrals 通过哈达玛分式积分求涉及汇合超几何函数的 GA-Convex 函数的 Maclaurin 型积分不等式
IF 5.4 2区 数学 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2023-12-02 DOI: 10.3390/fractalfract7120860
T. Chiheb, B. Meftah, Abdelkader Moumen, Mohamed Bouye
In this manuscript, by using a new identity, we establish some new Maclaurin-type inequalities for functions whose modulus of the first derivatives are GA-convex functions via Hadamard fractional integrals.
本文利用一个新的恒等式,通过Hadamard分数阶积分,对一阶导数的模为ga凸函数的函数,建立了一些新的maclaurin型不等式。
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引用次数: 0
An Algorithm for Crack Detection, Segmentation, and Fractal Dimension Estimation in Low-Light Environments by Fusing FFT and Convolutional Neural Network 融合FFT和卷积神经网络的弱光环境下裂纹检测、分割和分形维数估计算法
2区 数学 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2023-11-14 DOI: 10.3390/fractalfract7110820
Jiajie Cheng, Qiunan Chen, Xiaocheng Huang
The segmentation of crack detection and severity assessment in low-light environments presents a formidable challenge. To address this, we propose a novel dual encoder structure, denoted as DSD-Net, which integrates fast Fourier transform with a convolutional neural network. In this framework, we incorporate an information extraction module and an attention feature fusion module to effectively capture contextual global information and extract pertinent local features. Furthermore, we introduce a fractal dimension estimation method into the network, seamlessly integrated as an end-to-end task, augmenting the proficiency of professionals in detecting crack pathology within low-light settings. Subsequently, we curate a specialized dataset comprising instances of crack pathology in low-light conditions to facilitate the training and evaluation of the DSD-Net algorithm. Comparative experimentation attests to the commendable performance of DSD-Net in low-light environments, exhibiting superlative precision (88.5%), recall (85.3%), and F1 score (86.9%) in the detection task. Notably, DSD-Net exhibits a diminutive Model Size (35.3 MB) and elevated Frame Per Second (80.4 f/s), thereby endowing it with the potential to be seamlessly integrated into edge detection devices, thus amplifying its practical utility.
弱光环境下裂纹检测和严重程度评估的分割是一个严峻的挑战。为了解决这个问题,我们提出了一种新的双编码器结构,称为DSD-Net,它将快速傅里叶变换与卷积神经网络相结合。在该框架中,我们结合了信息提取模块和注意特征融合模块,有效地捕获上下文全局信息并提取相关的局部特征。此外,我们在网络中引入了一种分形维数估计方法,无缝集成为端到端任务,提高了专业人员在低光环境下检测裂纹病理的熟练程度。随后,我们策划了一个专门的数据集,包括在弱光条件下的裂缝病理实例,以促进DSD-Net算法的训练和评估。对比实验证明了DSD-Net在弱光环境下的良好性能,在检测任务中表现出最高的准确率(88.5%)、召回率(85.3%)和F1分数(86.9%)。值得注意的是,DSD-Net具有较小的模型尺寸(35.3 MB)和更高的每秒帧数(80.4 f/s),从而使其具有无缝集成到边缘检测设备的潜力,从而扩大了其实际效用。
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引用次数: 0
On Mixed Fractional Lifting Oscillation Spaces 关于混合分数阶提升振荡空间
2区 数学 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2023-11-13 DOI: 10.3390/fractalfract7110819
Imtithal Alzughaibi, Mourad Ben Slimane, Obaid Algahtani
We introduce hyperbolic oscillation spaces and mixed fractional lifting oscillation spaces expressed in terms of hyperbolic wavelet leaders of multivariate signals on Rd, with d≥2. Contrary to Besov spaces and fractional Sobolev spaces with dominating mixed smoothness, the new spaces take into account the geometric disposition of the hyperbolic wavelet coefficients at each scale (j1,⋯,jd), and are therefore suitable for a multifractal analysis of rectangular regularity. We prove that hyperbolic oscillation spaces are closely related to hyperbolic variation spaces, and consequently do not almost depend on the chosen hyperbolic wavelet basis. Therefore, the so-called rectangular multifractal analysis, related to hyperbolic oscillation spaces, is somehow ‘robust’, i.e., does not change if the analyzing wavelets were changed. We also study optimal relationships between hyperbolic and mixed fractional lifting oscillation spaces and Besov spaces with dominating mixed smoothness. In particular, we show that, for some indices, hyperbolic and mixed fractional lifting oscillation spaces are not always sharply imbedded between Besov spaces or fractional Sobolev spaces with dominating mixed smoothness, and thus are new spaces of a really different nature.
引入了d≥2的多元信号在Rd上用双曲小波前导表示的双曲振荡空间和混合分数阶提升振荡空间。与主导混合平滑的Besov空间和分数Sobolev空间相反,新空间考虑了每个尺度(j1,⋯jd)上双曲小波系数的几何配置,因此适合于矩形正则性的多重分形分析。我们证明了双曲振荡空间与双曲变分空间密切相关,因此几乎不依赖于所选择的双曲小波基。因此,与双曲振荡空间相关的所谓矩形多重分形分析在某种程度上具有“鲁棒性”,即即使分析小波发生变化也不会改变。研究了双曲型和混合分数阶提升振荡空间与具有混合光滑性的Besov空间之间的最优关系。特别地,我们证明了对于某些指标,双曲型和混合分数阶提升振荡空间并不总是尖锐地嵌套在具有混合光滑性的Besov空间或分数阶Sobolev空间之间,因此是真正不同性质的新空间。
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引用次数: 0
Phase Synchronization and Dynamic Behavior of a Novel Small Heterogeneous Coupled Network 一种新型小型异构耦合网络的相位同步与动态特性
2区 数学 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2023-11-13 DOI: 10.3390/fractalfract7110818
Mengjiao Wang, Jiwei Peng, Shaobo He, Xinan Zhang, Herbert Ho-Ching Iu
Studying the firing dynamics and phase synchronization behavior of heterogeneous coupled networks helps us understand the mechanism of human brain activity. In this study, we propose a novel small heterogeneous coupled network in which the 2D Hopfield neural network (HNN) and the 2D Hindmarsh–Rose (HR) neuron are coupled through a locally active memristor. The simulation results show that the network exhibits complex dynamic behavior and is different from the usual phase synchronization. More specifically, the membrane potential of the 2D HR neuron exhibits five stable firing modes as the coupling parameter k1 changes. In addition, it is found that in the local region of k1, the number of spikes in bursting firing increases with the increase in k1. More interestingly, the network gradually changes from synchronous to asynchronous during the increase in the coupling parameter k1 but suddenly becomes synchronous around the coupling parameter k1 = 1.96. As far as we know, this abnormal synchronization behavior is different from the existing findings. This research is inspired by the fact that the episodic synchronous abnormal firing of excitatory neurons in the hippocampus of the brain can lead to diseases such as epilepsy. This helps us further understand the mechanism of brain activity and build bionic systems. Finally, we design the simulation circuit of the network and implement it on an STM32 microcontroller.
研究异质耦合网络的放电动力学和相同步行为有助于我们理解人类大脑活动的机制。在这项研究中,我们提出了一种新的小型异构耦合网络,其中二维Hopfield神经网络(HNN)和二维Hindmarsh-Rose (HR)神经元通过局部有源记忆电阻器耦合。仿真结果表明,该网络表现出复杂的动态行为,不同于一般的相位同步。更具体地说,随着耦合参数k1的变化,二维HR神经元的膜电位呈现出五种稳定的放电模式。此外,发现在k1的局部区域,随着k1的增加,爆燃的尖峰数增加。更有趣的是,随着耦合参数k1的增加,网络逐渐由同步变为异步,但在耦合参数k1 = 1.96附近突然变为同步。据我们所知,这种异常的同步行为与现有的发现不同。这项研究的灵感来自于这样一个事实,即大脑海马体中兴奋性神经元的偶发性同步异常放电可以导致癫痫等疾病。这有助于我们进一步了解大脑活动的机制,并建立仿生系统。最后,设计了网络仿真电路,并在STM32单片机上实现。
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引用次数: 0
Solving a Nonlinear Fractional Differential Equation Using Fixed Point Results in Orthogonal Metric Spaces 利用正交度量空间中的不动点结果求解非线性分数阶微分方程
2区 数学 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2023-11-12 DOI: 10.3390/fractalfract7110817
Afrah Ahmad Noman Abdou
This research article aims to solve a nonlinear fractional differential equation by fixed point theorems in orthogonal metric spaces. To achieve our goal, we define an orthogonal Θ-contraction and orthogonal (α,Θ)-contraction in the setting of complete orthogonal metric spaces and prove fixed point theorems for such contractions. In this way, we consolidate and amend innumerable celebrated results in fixed point theory. We provide a non-trivial example to show the legitimacy of the established results.
利用不动点定理在正交度量空间中求解一类非线性分数阶微分方程。为了达到我们的目的,我们在完全正交度量空间的集合中定义了一个正交Θ-contraction和一个正交(α,Θ)-收缩,并证明了这些收缩的不动点定理。这样,我们巩固和修正了不动点理论中无数著名的成果。我们提供了一个非平凡的例子来证明所建立的结果的合法性。
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引用次数: 0
Systems of Hilfer–Hadamard Fractional Differential Equations with Nonlocal Coupled Boundary Conditions 具有非局部耦合边界条件的Hilfer-Hadamard分数阶微分方程组
2区 数学 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2023-11-11 DOI: 10.3390/fractalfract7110816
Alexandru Tudorache, Rodica Luca
We study the existence and uniqueness of solutions for a system of Hilfer–Hadamard fractional differential equations. These equations are subject to coupled nonlocal boundary conditions that incorporate Riemann–Stieltjes integrals and a range of Hadamard fractional derivatives. To establish our key findings, we apply various fixed point theorems, notably including the Banach contraction mapping principle, the Krasnosel’skii fixed point theorem applied to the sum of two operators, the Schaefer fixed point theorem, and the Leray–Schauder nonlinear alternative.
研究一类Hilfer-Hadamard分数阶微分方程解的存在唯一性。这些方程受耦合的非局部边界条件的约束,该条件包含Riemann-Stieltjes积分和一系列Hadamard分数阶导数。为了建立我们的关键发现,我们应用了各种不动点定理,特别是包括Banach收缩映射原理,Krasnosel 'skii不动点定理应用于两个算子的和,Schaefer不动点定理和Leray-Schauder非线性替代。
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引用次数: 0
Temporal Fractal Nature of the Time-Fractional SPIDEs and Their Gradient 时间分数型SPIDEs的分形性质及其梯度
2区 数学 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2023-11-11 DOI: 10.3390/fractalfract7110815
Wensheng Wang
Fractional and high-order PDEs have become prominent in theory and in the modeling of many phenomena. In this article, we study the temporal fractal nature for fourth-order time-fractional stochastic partial integro-differential equations (TFSPIDEs) and their gradients, which are driven in one-to-three dimensional spaces by space–time white noise. By using the underlying explicit kernels, we prove the exact global temporal continuity moduli and temporal laws of the iterated logarithm for the TFSPIDEs and their gradients, as well as prove that the sets of temporal fast points (where the remarkable oscillation of the TFSPIDEs and their gradients happen infinitely often) are random fractals. In addition, we evaluate their Hausdorff dimensions and their hitting probabilities. It has been confirmed that these points of the TFSPIDEs and their gradients, in time, are most likely one everywhere, and are dense with the power of the continuum. Moreover, their hitting probabilities are determined by the target set B’s packing dimension dimp(B). On the one hand, this work reinforces the temporal moduli of the continuity and temporal LILs obtained in relevant literature, which were achieved by obtaining the exact values of their normalized constants; on the other hand, this work obtains the size of the set of fast points, as well as a potential theory of TFSPIDEs and their gradients.
分数阶和高阶偏微分方程在理论和许多现象的建模中已经变得突出。本文研究了在一至三维空间中由时空白噪声驱动的四阶时间分数阶随机偏积分微分方程(TFSPIDEs)及其梯度的分形性质。通过使用隐含的显式核,我们证明了TFSPIDEs及其梯度的精确的全局时间连续模和迭代对数的时间规律,并证明了时间快点集合(TFSPIDEs及其梯度的显著振荡无限频繁地发生)是随机分形。此外,我们还评估了它们的豪斯多夫维数和命中概率。已经证实,TFSPIDEs的这些点及其梯度在时间上很可能无处不在,并且随着连续统的功率而密集。它们的命中概率由目标集B的聚类维差(B)决定。一方面,本文的工作强化了相关文献中获得的连续性和时序lls的时间模量,这是通过获得它们的归一化常数的精确值来实现的;另一方面,本工作得到了快速点集合的大小,以及TFSPIDEs及其梯度的潜在理论。
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引用次数: 0
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Fractal and Fractional
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