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Inverse Differential Operators in Time and Space
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作者 Edwin Eugene Klingman 《Journal of Applied Mathematics and Physics》 2023年第12期3789-3799,共11页
When one function is defined as a differential operation on another function, it’s often desirable to invert the definition, to effectively “undo” the differentiation. A Green’s function approach is often used to ... When one function is defined as a differential operation on another function, it’s often desirable to invert the definition, to effectively “undo” the differentiation. A Green’s function approach is often used to accomplish this, but variations on this theme exist, and we examine a few such variations. The mathematical analysis of  is sought in the form  if such an inverse operator exists, but physics is defined by both mathematical formula and ontological formalism, as I show for an example based on the Dirac equation. Finally, I contrast these “standard” approaches with a novel exact inverse operator for field equations. 展开更多
关键词 Matrix-Inverse differential operators Green’s functions Dirac’s Equation Wave Equations Inverse Curl Operator
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Numerical Solution of System of Fractional Delay Differential Equations Using Polynomial Spline Functions
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作者 Mahmoud N. Sherif 《Applied Mathematics》 2016年第6期518-526,共9页
The aim of this paper is to approximate the solution of system of fractional delay differential equations. Our technique relies on the use of suitable spline functions of polynomial form. We introduce the description ... The aim of this paper is to approximate the solution of system of fractional delay differential equations. Our technique relies on the use of suitable spline functions of polynomial form. We introduce the description of the proposed approximation method. The error analysis and stability of the method are theoretically investigated. Numerical example is given to illustrate the applicability, accuracy and stability of the proposed method. 展开更多
关键词 Fractional differential Equation spline functions Taylor Expansion STABILITY
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AN INTEGRATION METHOD WITH FITTING CUBIC SPLINE FUNCTIONS TO A NUMERICAL MODEL OF 2ND-ORDER SPACE-TIME DIFFERENTIAL REMAINDER——FOR AN IDEAL GLOBAL SIMULATION CASE WITH PRIMITIVE ATMOSPHERIC EQUATIONS
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作者 辜旭赞 张兵 王明欢 《Journal of Tropical Meteorology》 SCIE 2013年第4期388-396,共9页
In this paper,the forecasting equations of a 2nd-order space-time differential remainder are deduced from the Navier-Stokes primitive equations and Eulerian operator by Taylor-series expansion.Here we introduce a cubi... In this paper,the forecasting equations of a 2nd-order space-time differential remainder are deduced from the Navier-Stokes primitive equations and Eulerian operator by Taylor-series expansion.Here we introduce a cubic spline numerical model(Spline Model for short),which is with a quasi-Lagrangian time-split integration scheme of fitting cubic spline/bicubic surface to all physical variable fields in the atmospheric equations on spherical discrete latitude-longitude mesh.A new algorithm of"fitting cubic spline—time step integration—fitting cubic spline—……"is developed to determine their first-and2nd-order derivatives and their upstream points for time discrete integral to the governing equations in Spline Model.And the cubic spline function and its mathematical polarities are also discussed to understand the Spline Model’s mathematical foundation of numerical analysis.It is pointed out that the Spline Model has mathematical laws of"convergence"of the cubic spline functions contracting to the original functions as well as its 1st-order and 2nd-order derivatives.The"optimality"of the 2nd-order derivative of the cubic spline functions is optimal approximation to that of the original functions.In addition,a Hermite bicubic patch is equivalent to operate on a grid for a 2nd-order derivative variable field.Besides,the slopes and curvatures of a central difference are identified respectively,with a smoothing coefficient of 1/3,three-point smoothing of that of a cubic spline.Then the slopes and curvatures of a central difference are calculated from the smoothing coefficient 1/3 and three-point smoothing of that of a cubic spline,respectively.Furthermore,a global simulation case of adiabatic,non-frictional and"incompressible"model atmosphere is shown with the quasi-Lagrangian time integration by using a global Spline Model,whose initial condition comes from the NCEP reanalysis data,along with quasi-uniform latitude-longitude grids and the so-called"shallow atmosphere"Navier-Stokes primitive equations in the spherical coordinates.The Spline Model,which adopted the Navier-Stokes primitive equations and quasi-Lagrangian time-split integration scheme,provides an initial ideal case of global atmospheric circulation.In addition,considering the essentially non-linear atmospheric motions,the Spline Model could judge reasonably well simple points of any smoothed variable field according to its fitting spline curvatures that must conform to its physical interpretation. 展开更多
关键词 NUMERICAL forecast and NUMERICAL SIMULATION 2nd-order SPACE-TIME differential REMAINDER NUMERICAL model cubic spline functions Navier-Stokes PRIMITIVE EQUATIONS quasi-Lagrangian time-split integration scheme global SIMULATION case
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ON APPROXIMATION OF SMOOTH FUNCTIONS FROM NULL SPACES OF OPTIMAL LINEAR DIFFERENTIAL OPERATORS WITH CONSTANT COEFFICIENTS
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作者 Vesselin Vatchev 《Analysis in Theory and Applications》 2011年第2期187-200,共14页
For a real valued function f defined on a finite interval I we consider the problem of approximating f from null spaces of differential operators of the form Ln(ψ) =∑k=0^n akψ(k) where the constant coefficients... For a real valued function f defined on a finite interval I we consider the problem of approximating f from null spaces of differential operators of the form Ln(ψ) =∑k=0^n akψ(k) where the constant coefficients ak C R may be adapted to f. 展开更多
关键词 approximation of analytic function differential operator fundamental set of solutions
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LEIBNIZ′FORMULA OF GENERALIZED DIFFERENCE WITH RESPECT TO A CLASS OF DIFFERENTIAL OPERATORS AND RECURRENCE FORMULA OF THEIR GREEN′S FUNCTION 被引量:1
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作者 许跃生 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1984年第3期1359-1364,共6页
In this paper, Leibniz' formula of generalized divided difference with respect to a class of differential operators whose basic sets of solutions have power form, is considered. The recurrence formula of Green fun... In this paper, Leibniz' formula of generalized divided difference with respect to a class of differential operators whose basic sets of solutions have power form, is considered. The recurrence formula of Green function about the operators is also given. 展开更多
关键词 LEIBNIZ S FUNCTION FORMULA OF GENERALIZED DIFFERENCE WITH RESPECT TO A CLASS OF differential operators AND RECURRENCE FORMULA OF THEIR GREEN
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On the Cardinal Spline Interpolation Corresponding to Infinite Order Differential Operators
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作者 Chen Dirong Department of Mathematics Beijing Normal University Beijing,100875 and Center for Mathematical Sciences Zhejiang University Hangzhou,310027 China 《Acta Mathematica Sinica,English Series》 SCIE CSCD 1994年第3期315-324,共10页
This paper discusses some problems on the cardinal spline interpolation correspond- ing to infinite order differential operators.The remainder formulas and a dual theorem are es- tablished for some convolution classes... This paper discusses some problems on the cardinal spline interpolation correspond- ing to infinite order differential operators.The remainder formulas and a dual theorem are es- tablished for some convolution classes,where the kernels are PF densities.Moreover,the exact error of approximation of a convolution class with interpolation cardinal splines is determined. The exact values of average n-Kolmogorov widths are obtained for the convolution class. 展开更多
关键词 MATH On the Cardinal spline Interpolation Corresponding to Infinite Order differential operators LIM CHEN 卜成
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Boundedness for Multilinear Operators of Pseudo-Differential Operators
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作者 Jiasheng Zeng Rongping Chen +2 位作者 Jiangang Liu Xiaojing Wang Chunsheng Liu 《Advances in Pure Mathematics》 2023年第7期449-462,共14页
In this paper, we establish a sharp function estimate for the multilinear integral operators associated to the pseudo-differential operators. As the application, we obtain the L<sup>p</sup> (1 p norm ... In this paper, we establish a sharp function estimate for the multilinear integral operators associated to the pseudo-differential operators. As the application, we obtain the L<sup>p</sup> (1 p norm inequalities for the multilinear operators. 展开更多
关键词 Multilinear Operator Pseudo-differential Operator Sharp Function Estimate BMO
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DIFFERENTIAL OPERATORS OF INFINITE ORDER IN THE SPACE OF RAPIDLY DECREASING SEQUENCES
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作者 M.MALDONADO J.PRADA M.J.SENOSIAIN 《Acta Mathematica Scientia》 SCIE CSCD 2016年第2期325-333,共9页
We consider the space of rapidly decreasing sequences s and the derivative operator D defined on it. The object of this article is to study the equivalence of a differential operator of infinite order; that is φ(D)... We consider the space of rapidly decreasing sequences s and the derivative operator D defined on it. The object of this article is to study the equivalence of a differential operator of infinite order; that is φ(D) =^∞∑k=0φkD^k.φk constant numbers an a power of D.Dn, meaning, is there a isomorphism X (from s onto s) such that Xφ(D) = D^nX?. We prove that if φ(D) is equivalent to Dn, then φ(D) is of finite order, in fact a polynomial of degree n. The question of the equivalence of two differential operators of finite order in the space s is addressed too and solved completely when n = 1. 展开更多
关键词 Ordinary differential operators sequence spaces operators on function spaces
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ESSENTIAL NORMS OF PRODUCTS OF WEIGHTED COMPOSITION OPERATORS AND DIFFERENTIATION OPERATORS BETWEEN BANACH SPACES OF ANALYTIC FUNCTIONS 被引量:4
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作者 Jasbir Singh MANHAS Ruhan ZHAO 《Acta Mathematica Scientia》 SCIE CSCD 2015年第6期1401-1410,共10页
We obtain several estimates of the essential norms of the products of differen- tiation operators and weighted composition operators between weighted Banach spaces of analytic functions with general weights. As applic... We obtain several estimates of the essential norms of the products of differen- tiation operators and weighted composition operators between weighted Banach spaces of analytic functions with general weights. As applications, we also give estimates of the es- sential norms of weighted composition operators between weighted Banach space of analytic functions and Bloch-type spaces. 展开更多
关键词 differentiation operators weighted composition operators weighted Banachspace of analytic functions Bloch-type spaces essential norms
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Embedding and Maximal Regular Differential Operators in Sobolev-Lions Spaces 被引量:2
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作者 Veli B.SHAKHMUROV 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2006年第5期1493-1508,共16页
This study focuses on vector-valued anisotropic Sobolev-Lions spaces associated with Banach spaces E0, E. Several conditions are found that ensure the continuity and compactness of embedding operators that are optimal... This study focuses on vector-valued anisotropic Sobolev-Lions spaces associated with Banach spaces E0, E. Several conditions are found that ensure the continuity and compactness of embedding operators that are optimal regular in these spaces in terms of interpolations of spaces E0 and E. In particular, the most regular class of interpolation spaces Eα between E0, E depending on α and the order of space are found and the boundedness of differential operators D^α from this space to Eα-valued Lp,γ spaces is proved. These results are applied to partial differential-operator equations with parameters to obtain conditions that guarantee the maximal Lp,γ regularity and R-positivity uniformly with respect to these parameters. 展开更多
关键词 embedding operators Banach-valued function spaces differential operator equations (DOE) maximal regularity operator-valued Fourier multipliers interpolation of Banach spaces
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Some Basic Properties for Certain Classes of p-valent Analytic Functions Using Differential Operator 被引量:1
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作者 ZHANG Hai- Yan TANG Huo +1 位作者 LI Shu-Hai MA Li-Na 《Chinese Quarterly Journal of Mathematics》 2018年第2期132-139,共8页
In this paper, we introduce new subclasses of p-valent analytic functions defined by using differential operator in the open unit disc. We study coefficient inequality, distortion theorem, radius of close to-convexity... In this paper, we introduce new subclasses of p-valent analytic functions defined by using differential operator in the open unit disc. We study coefficient inequality, distortion theorem, radius of close to-convexity, starlikeness and convexity, extreme points and integral operator for functions in these new subclasses. 展开更多
关键词 p-valent functions differential operator Coefficient inequality Distortion theorem RADIUS
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Finite Dimensional Approximation of the Monodromy Operator of a Periodic Delay Differential Equation with Piecewise Constant Orthonormal Functions
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作者 Eli A. Vazquez Joaquin Collado 《Applied Mathematics》 2018年第11期1315-1337,共23页
Using piecewise constant orthonormal functions, an approximation of the monodromy operator of a Linear Periodic Delay Differential Equation (PDDE) is obtained by approximating the integral equation corresponding to th... Using piecewise constant orthonormal functions, an approximation of the monodromy operator of a Linear Periodic Delay Differential Equation (PDDE) is obtained by approximating the integral equation corresponding to the PDDE as a linear operator over the space of initial conditions. This approximation allows us to consider the state space as finite dimensional resulting in a finite matrix approximation whose spectrum converges to the spectrum of the monodromy operator. 展开更多
关键词 MONODROMY Operator PERIODIC Delay differential Equations WALSH functions Block Pulse functions Finite Rank Approximation
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New Results Subclasses of Analytic Functions Define by Opooladifferential Operator
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作者 Fatunsin L. M. Opoola T.O. 《Journal of Mathematics and System Science》 2017年第10期289-295,共7页
In this paper, using Opooladifferential operator, we introduce new subclasses of univalent functions andprovide δ -Neigbhourhoods properties, Inclusion relations for the subclasses of univalent functions.
关键词 Univalent functions Normalised Identity function δ-Neigbhourhoods Inclusion relations Opoola differential operator.
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Numerical Solution of Functional Integral and Integro-Differential Equations by Using B-Splines
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作者 Hesam-Eldien Derili Gherjalar Hossein Mohammadikia 《Applied Mathematics》 2012年第12期1940-1944,共5页
This paper describes an approximating solution, based on Lagrange interpolation and spline functions, to treat functional integral equations of Fredholm type and Volterra type. This method extended to functional integ... This paper describes an approximating solution, based on Lagrange interpolation and spline functions, to treat functional integral equations of Fredholm type and Volterra type. This method extended to functional integral and integro-differential equations. For showing efficiency of the method we give some numerical examples. 展开更多
关键词 LAGRANGE Interpolation B-spline functions FUNCTIONAL Integral EQUATION FUNCTIONAL Integro-differential EQUATION FUNCTIONAL differential EQUATION
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DIFFERENTIAL INEQUALITIES OF OPERATOR-VALUED ANALYTIC FUNCTIONS
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作者 蹇明 《Acta Mathematica Scientia》 SCIE CSCD 2001年第2期166-170,共5页
Some differential inequalities and integral inequalities for operator-valued an- alytic functions are investigated.
关键词 Proper contraction operator-valued analytic function differential inequality integral inequality
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基于拉普拉斯金字塔残差网络的多尺度图像压缩研究
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作者 田学军 章文强 +3 位作者 马梓轩 陈良哲 叶卉荣 舒忠 《印刷与数字媒体技术研究》 CAS 北大核心 2024年第5期33-44,共12页
为了更好地进行图像重建,加强对图像多尺度特征表示和特征融合的处理,本研究提出一种新的多尺度特征融合图像重建网络模型。模型包括迭代降采样和迭代上采样过程。迭代降采样过程是通过在拉普拉斯金字塔残差控制网络模型中将高斯卷积核... 为了更好地进行图像重建,加强对图像多尺度特征表示和特征融合的处理,本研究提出一种新的多尺度特征融合图像重建网络模型。模型包括迭代降采样和迭代上采样过程。迭代降采样过程是通过在拉普拉斯金字塔残差控制网络模型中将高斯卷积核与子采样和高斯平滑滤波迭代操作规则相结合完成的。迭代上采样过程是通过使用拉普拉斯卷积核和二阶差分操作规则实现的。GJ-UNet深度学习网络模型通过其编码器下采样模块实现图像多尺度语义特征的精细分类,并在解码器上采样模块中应用反卷积和卷积操作规则,规范处理图像多尺度语义特征。实验表明,所提出的方法可以实现高精度的特征提取,同时对于图像特征融合的相关性更强,提取的图像边缘信息更清晰且相对噪声信息更低,重建图像的视觉效果基本与原始输入图像相同。本研究有望广泛应用于计算机图像视觉领域。 展开更多
关键词 压缩感知图像重构 图像多尺度特征 拉普拉斯金字塔模型 差分运算 GJ-UNet深度学习网络模型 Dice损失函数
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基于观测数据的地表太阳形状B-样条函数模型
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作者 沈童 赵乐 冯结青 《计算机科学》 CSCD 北大核心 2024年第1期215-224,共10页
描述地面上接收太阳辐射能分布的函数被称为地表太阳形状模型。它对塔式光热太阳能发电中接收器上辐射能密度分布的精确仿真至关重要。光晕辐射能占太阳辐射总能量的百分比,也被称为光晕辐射能占比(CircumSolar Ratio,CSR),它是地表太... 描述地面上接收太阳辐射能分布的函数被称为地表太阳形状模型。它对塔式光热太阳能发电中接收器上辐射能密度分布的精确仿真至关重要。光晕辐射能占太阳辐射总能量的百分比,也被称为光晕辐射能占比(CircumSolar Ratio,CSR),它是地表太阳形状模型中的一个重要参数。目前,常用的地表太阳形状模型普遍存在精度不高、计算所得CSR无法与输入CSR对齐、辐射能分布不连续、模型函数不能解析积分等不足。针对这些问题,文中提出了基于观测数据拟合的地表太阳形状张量积B-样条函数模型。首先,对两个观测数据集进行数据清洗、去噪、归一化、分组平均和拼接,得到具有不同CSR值、随入射角度偏移θ变化的84组太阳辐射能扫描剖面数据;其次,选择变化最剧烈的CSR为0.005这组数据,以θ为自变量,进行带约束的B-样条函数拟合(二次规划问题),拟合过程中,通过差分进化算法优化节点向量,并通过实验确定最优控制系数的数量;然后,采用上述节点向量、控制系数数量,以相同的方式拟合其他CSR值的83组数据;最后,将所得84个单变量B-样条函数模型作为输入,以CSR为自变量对其控制系数进行拟合,并类似地确定节点向量和控制系数数目,最终得到以CSR和θ为自变量、具有12×15个控制系数的张量积B-样条函数模型,即地表太阳形状模型。与已有模型相比,该B-样条函数模型是一个C2光滑的模型,具有CSR对齐、拟合精度高和辐射能分布可解析积分的优点。 展开更多
关键词 太阳形状模型 CSR对齐 B-样条函数拟合 二次规划 差分进化算法
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基于格林函数正交各向异性切口板自由振动特性分析
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作者 杨永育 李腾岳 +2 位作者 程长征 赵航 葛仁余 《振动与冲击》 EI CSCD 北大核心 2024年第5期182-187,201,共7页
正交异性板因重量轻、承载能力强等优点而被广泛运用于工程结构。基于格林函数,结合新兴的近场动力学微分算子(peridynamic differential operator, PDDO),提出一种分析正交各向异性板自由振动特性的方法。首先,将振动控制方程中的位移... 正交异性板因重量轻、承载能力强等优点而被广泛运用于工程结构。基于格林函数,结合新兴的近场动力学微分算子(peridynamic differential operator, PDDO),提出一种分析正交各向异性板自由振动特性的方法。首先,将振动控制方程中的位移函数假设为含格林函数的一阶积分形式;其次,将线性四阶偏微分方程分别在切口板的径向和周向离散成代数方程;最后,通过PDDO构造插值函数表示径向和周向非公共离散点位移,建立自由振动广义特征方程,获得正交各向异性切口板自振频率及振型,证明了该方法的准确性,并分析切口几何参数对结构振动特性的影响规律,为板壳结构设计提供支撑。 展开更多
关键词 正交各向异性切口板 自由振动 格林函数 近场动力学微分算子(PDDO)
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Operator Methods in High Order Partial Differential Equation 被引量:1
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作者 毕光庆 《Chinese Quarterly Journal of Mathematics》 CSCD 2001年第1期88-101,共14页
For linear partial differential equation 〔 2t 2-a 2P( x)〕 m u=f(x,t), where m1,X∈R n,t∈R 1, the author gives the analytic solution of the initial value problem using the operators sh(tP( x) 1/2 )... For linear partial differential equation 〔 2t 2-a 2P( x)〕 m u=f(x,t), where m1,X∈R n,t∈R 1, the author gives the analytic solution of the initial value problem using the operators sh(tP( x) 1/2 )P( x) 1/2 . By representing the operators with integrals, explicit solutions are obtained with an integral form of a given function. 展开更多
关键词 SH operators parial differential equation infinite order differential operators h k(x τ)function
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基于改进遗传算法的酒店配送机器人路径规划仿真研究
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作者 戚英杰 李建荣 李雪林 《江苏建筑职业技术学院学报》 2024年第1期64-68,共5页
针对传统遗传算法初始种群质量不高、种群多样性不足和路径长度不理想的问题,提出了改进遗传算法。通过基于引力场模型生成初始路径,提高初始种群质量;在适应度函数中增加了惩罚因子和激励因子,提升种群质量筛选;引入差分进化算法对种... 针对传统遗传算法初始种群质量不高、种群多样性不足和路径长度不理想的问题,提出了改进遗传算法。通过基于引力场模型生成初始路径,提高初始种群质量;在适应度函数中增加了惩罚因子和激励因子,提升种群质量筛选;引入差分进化算法对种群个体之间的差异进行向量化操作,以突变概率控制种群突变数量,优化种群多样性,从而更好更快地得到全局最优解。采用改进遗传算法、传统遗传算法和蚁群算法对不同栅格地图路径规划进行仿真实验,结果表明:改进遗传算法在处理此类路径规划问题时可以快速找到最优路径,在复杂度较高的M3地图环境下相较于传统遗传算法和蚁群算法最优路径分别缩短了17.39%和7.9%。 展开更多
关键词 改进遗传算法 差分进化算法 路径规划 种群初始化 适应度函数 突变算子
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