搜索到78401篇“ FRACTIONAL“的相关文章
调和分数Ornstein-Uhlenbeck金融模型的参数估计
2025年
为了描述金融资产价格过程的长相依性和自相似性,首先构建由调和分数布朗运动驱动的分数Ornstein-Uhlenbeck(O-U)模型.由于调和分数布朗运动是分数布朗运动的推广,故所构建的模型具有更广泛的应用.然后基于离散观测样本,利用最小二乘方法,得到模型漂移参数的估计量,并证明了估计量的相合性和渐近分布.最后,通过模拟展示了所得估计量的有限样本性质,模拟结果显示估计量的值拟合参数真值的效果较好.
王继霞王琳李浩然
关键词:ORNSTEIN-UHLENBECK过程相合性渐近分布
光电稳定平台的分数阶降阶自抗扰控制设计
2025年
为了提高光电稳定平台的动态性能与抗干扰能力,提出一种分数阶降阶自抗扰控制(FO-RADRC)算法。首先,利用系统输出信号的可测性和可靠性,采用降阶线性扩张状态观测器,提高观测效率和精度;然后,采用分数阶PD(FOPD)作为控制律,从而增强系统的稳定性和控制性能。通过数值仿真实验,与线性自抗扰算法和降阶线性自抗扰算法进行了对比分析。结果表明,所提算法在动态性能指标上均优于对比算法,且在不同频率的等效扰动作用下具有更强的扰动抑制能力。这些结果验证了所提改进算法在提升光电稳定平台控制效果方面的有效性和创新性。
陈旭邸宏伟林国余陈佳明
关键词:自抗扰控制
不同分数阶微分形式在盐渍土电导率高光谱反演中的适用性研究
2025年
近年来,部分学者将分数阶微分理论应用到盐渍土电导率高光谱反演中,取得了较为显著的效果。然而,已有研究多采用Grünwald-Letnikov分数阶微分定义形式,对于Riemann-Liouville、Caputo分数阶微分定义形式的应用研究较少,Riemann-Liouville、Caputo分数阶微分定义形式在盐渍土电导率高光谱反演中的适用性尚不明确。基于实测土壤电导率和高光谱数据,考虑常见的Grünwald-Letnikov、Riemann-Liouville和Caputo三类分数阶微分定义形式,通过软件编程实现Grünwald-Letnikov、Riemann-Liouville、Caputo分数阶微分处理函数,比较分析了不同分数阶微分定义形式下,土样高光谱数据在同阶微分处理后的差异性以及随阶数增加后的变化特征。结果表明:土样光谱反射率曲线在不同分数阶微分定义形式下,同阶微分处理后表现出较大差异;在0.1~1阶范围内,随微分阶数的增加,Grünwald-Letnikov、Riemann-Liouville、Caputo分数阶微分处理后高度变异波段数量均呈现出增加趋势;当微分阶数趋于1时,光谱反射率微分值逐渐降低且向0值逼近,波动范围逐渐减小,而光谱数据的变异性却随着波动范围的减小而增强;Grünwald-Letnikov分数阶微分处理在0.6、0.7阶相关系数提升9.5%、6.7%,Riemann-Liouville和Caputo分数阶微分处理后,相关系数分别在0.8~0.9阶、0.7~0.9阶提升1%左右。该研究为高光谱数据预处理提供了一种新的研究思路,为更好的将分数阶微分理论应用到土壤盐渍化遥感反演中提供参考。
周凤玺滕祥帅郝君明王立业
关键词:盐渍土电导率光谱反射率分数阶微分
On limit fractional Volterra hierarchies
2024年
For the limit fractional Volterra(LFV)hierarchy,we construct the n-fold Darboux transformation and the soliton solutions.Furthermore,we extend the LFV hierarchy to the noncommutative LFV(NCLFV)hierarchy,and construct the Darboux transformation expressed by quasi determinant of the noncommutative version.Meanwhile,we establish the relationship between new and old solutions of the NCLFV hierarchy.Finally,the quasi determinant solutions of the NCLFV hierarchy are obtained.
Lixiang ZhangChuanzhong Li
点阵光电技术在眶周年轻化中的应用进展
2024年
眶周是最早体现衰老的区域之一,能真实地反映一个人的衰老程度。眶周老化涉及到黑眼圈、皱纹、泪沟、眼袋等多种问题,会让人出现疲惫、沮丧或愤怒的外观。点阵光电技术采用局灶性光热作用原理,可形成数十个显微热损伤区,刺激胶原再生,使周围正常皮肤组织快速修复,被广泛应用于眶周年轻化的治疗中。本文将对点阵光电技术在眶周年轻化中的应用进行综述,以期为临床实践提供参考。
燕丽陈小英潘萌
关键词:点阵激光光电技术
Binding Number and Fractional k-Factors of Graphs
2024年
In this paper, we consider the relationship between the binding number and the existence of fractional k-factors of graphs. The binding number of G is defined by Woodall as bind(G)=min{ | NG(X) || X |:∅≠X⊆V(G) }. It is proved that a graph G has a fractional 1-factor if bind(G)≥1and has a fractional k-factor if bind(G)≥k−1k. Furthermore, it is showed that both results are best possible in some sense.
Renying Chang
Global Well-Posedness of the Fractional Tropical Climate Model
2024年
In this paper, we consider the Cauchy problem of 3-dimensional tropical climate model. This model reflects the interaction and coupling among the barotropic mode u, the first baroclinic mode v of the velocity and the temperature θ. The systems with fractional dissipation studied here may arise in the modeling of geophysical circumstances. Mathematically these systems allow simultaneous examination of a family of systems with various levels of regularization. The aim here is the global strong solution with the least dissipation. By energy estimate and delicate analysis, we prove the existence of global solution under three different cases: first, with the help of damping terms, the global strong solution of the system with Λ2au, Λv and Λ θ for;and second, the global strong solution of the system for with damping terms;finally, the global strong solution of the system for without any damping terms, which improve the known existence theory for this system.
Meiqi Hu
一种适用于分数电平MMC的改进分数电平调制策略
2024年
分数电平模块化多电平换流器(fractional level modular multilevel converter,FLMMC)可有效改善少子模块MMC的电压质量,但在现有分数电平调制(fractional level modulation,FLM)策略下存在开关损耗较高问题。为降低FLMMC的开关损耗,提出了一种包含子模块能量均衡环节和子模块分类投切环节的改进FLM策略。在能量均衡环节,常规子模块和分数电平子模块均参与每次电平变化时的排序与投切,以实现两种类型子模块之间的能量均衡;在分类投切环节,常规子模块和分数电平子模块根据电平是整数或分数分别进行排序与投切,以减少功率器件的开关次数。基于Matlab/Simulink的仿真结果及物理实验结果表明,所提改进FLM策略可显著降低FLMMC的开关损耗,并获得良好的电平倍增效果。
王琛余欣洋王毅韩创
关键词:模块化多电平换流器开关损耗电压质量
Legendre-Weighted Residual Methods for System of Fractional Order Differential Equations
2024年
The numerical approach for finding the solution of fractional order systems of boundary value problems (BPVs) is derived in this paper. The implementation of the weighted residuals such as Galerkin, Least Square, and Collocation methods are included for solving fractional order differential equations, which is broadened to acquire the approximate solutions of fractional order systems with differentiable polynomials, namely Legendre polynomials, as basis functions. The algorithm of the residual formulations of matrix form can be coded efficiently. The interpretation of Caputo fractional derivatives is employed here. We have demonstrated these methods numerically through a few examples of linear and nonlinear BVPs. The results in absolute errors show that the present method efficiently finds the numerical solutions of fractional order systems of differential equations.
Umme RumanMd. Shafiqul Islam
Analytical study of atmospheric internal waves model with fractional approach
2024年
This study looks at the mathematical model of internal atmospheric waves,often known as gravity waves,occurring inside a fluid rather than on the surface.Under the shallow-fluid assumption,internal atmospheric waves may be described by a nonlinear partial differential equation system.The shallow flow model’s primary concept is that the waves are spread out across a large horizontal area before rising vertically.The Fractional Reduced Differential Transform Method(FRDTM)is applied to provide approximate solutions for any given model.This aids in the modelling of the global atmosphere,which has applications in weather and climate forecasting.For the integer-order value(α=1),the FRDTM solution is compared to the precise solution,EADM,and HAM to assess the correctness and efficacy of the proposed technique.
Trushit PatelHardik PatelRamakanta Meher

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徐保根
作品数:139被引量:340H指数:12
供职机构:华东交通大学
研究主题:控制数 优美图 非连通图 符号边控制数 符号边控制函数
邹妍
作品数:8被引量:9H指数:3
供职机构:华东交通大学
研究主题:控制数 FRACTIONAL 控制函数 类图 联图
隽志才
作品数:207被引量:1,645H指数:22
供职机构:上海交通大学安泰经济与管理学院
研究主题:交通流 城市交通 通勤 交通工程 非集计模型
鲜于建川
作品数:32被引量:154H指数:8
供职机构:上海电机学院商学院
研究主题:通勤 LOGIT模型 通勤出行 出行链 城市交通
胥德平
作品数:32被引量:61H指数:5
供职机构:成都理工大学信息工程学院数学地质四川省重点实验室
研究主题:KRONECKER积 组合差商法 上(下)半连续 色散方程 储层识别