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Relations of 3D directional derivatives and expressions of typical differential operators 被引量:3
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作者 YIN Li Lü Gui-xia SHEN Long-jun Laboratory of Computational Physics,Institute of Applied Physics and Computational Mathematics,Beijing 100088,China 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2009年第2期221-229,共9页
Relations of the 3D multi-directional derivatives are studied in this paper. These relations are applied to a geeral second-order linear elliptical operator and the corresponding expression are obtained. These relatio... Relations of the 3D multi-directional derivatives are studied in this paper. These relations are applied to a geeral second-order linear elliptical operator and the corresponding expression are obtained. These relations and expressions play important roles in the meshless finite point method. 展开更多
关键词 3D directional derivative general elliptical operator
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EXISTENCE AND STABILITY RESULTS FOR GENERALIZED FRACTIONAL DIFFERENTIAL EQUATIONS 被引量:3
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作者 A.BEN MAKHLOUF D.BOUCENNA M.A.HAMMAMI 《Acta Mathematica Scientia》 SCIE CSCD 2020年第1期141-154,共14页
In this paper,a sufficient conditions to guarantee the existence and stability of solutions for generalized nonlinear fractional differential equations of orderα(1<α<2)are given.The main results are obtained b... In this paper,a sufficient conditions to guarantee the existence and stability of solutions for generalized nonlinear fractional differential equations of orderα(1<α<2)are given.The main results are obtained by using Krasnoselskii's fixed point theorem in a weighted Banach space.Two examples are given to demonstrate the validity of the proposed results. 展开更多
关键词 nonlinear FRACTIONAL differential EQUATIONS STABILITY analysis generalized FRACTIONAL derivative Krasnoselskii's fixed point THEOREM
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Optimality for Henig Proper Efficiency in Vector Optimization Involving Dini Set-Valued Directional Derivatives
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作者 Guolin Yu Huaipeng Bai 《Applied Mathematics》 2011年第7期922-925,共4页
This note studies the optimality conditions of vector optimization problems involving generalized convexity in locally convex spaces. Based upon the concept of Dini set-valued directional derivatives, the necessary an... This note studies the optimality conditions of vector optimization problems involving generalized convexity in locally convex spaces. Based upon the concept of Dini set-valued directional derivatives, the necessary and sufficient optimality conditions are established for Henig proper and strong minimal solutions respectively in generalized preinvex vector optimization problems. 展开更多
关键词 VECTOR Optimization Dini SET-VALUED directional derivative generalized Preinvex Function Henig PROPER Efficiency
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Extension of covariant derivative(Ⅰ): From component form to objective form 被引量:4
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作者 Ya-Jun Yin 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第1期79-87,共9页
This paper extends the covariant derivative un der curved coordinate systems in 3D Euclid space. Based on the axiom of the covariant form invariability, the classical covariant derivative that can only act on componen... This paper extends the covariant derivative un der curved coordinate systems in 3D Euclid space. Based on the axiom of the covariant form invariability, the classical covariant derivative that can only act on components is ex tended to the generalized covariant derivative that can act on any geometric quantity including base vectors, vectors and tensors. Under the axiom, the algebra structure of the gen eralized covariant derivative is proved to be covariant dif ferential ring. Based on the powerful operation capabilities and simple analytical properties of the generalized covariant derivative, the tensor analysis in curved coordinate systems is simplified to a large extent. 展开更多
关键词 Tensor analysis Classical covariant derivatives generalized covariant derivatives The axiom of the covari-ant form invariability Covariant differential ring
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Extension of covariant derivative(Ⅱ): From flat space to curved space 被引量:4
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作者 Ya-Jun Yin 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第1期88-95,共8页
This paper extends the classical covariant deriva tive to the generalized covariant derivative on curved sur faces. The basement for the extension is similar to the pre vious paper, i.e., the axiom of the covariant fo... This paper extends the classical covariant deriva tive to the generalized covariant derivative on curved sur faces. The basement for the extension is similar to the pre vious paper, i.e., the axiom of the covariant form invariabil ity. Based on the generalized covariant derivative, a covari ant differential transformation group with orthogonal duality is set up. Through such orthogonal duality, tensor analy sis on curved surfaces is simplified intensively. Under the covariant differential transformation group, the differential invariabilities and integral invariabilities are constructed on curved surfaces. 展开更多
关键词 Tensor analysis on curved surfaces Classicalcovariant derivative and generalized covariant derivative Axiom of the covariant form invariability Covariant differ-ential transformation group differential invariabilities andintegral invariabilities
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Two-Order Approximate and Large Stepsize Numerical Direction Based on the Quadratic Hypothesis and Fitting Method 被引量:3
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作者 Xiaoli Yin Chunming Li Yuan Zhang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2020年第3期901-909,共9页
Many effective optimization algorithms require partial derivatives of objective functions, while some optimization problems' objective functions have no derivatives. According to former research studies, some sear... Many effective optimization algorithms require partial derivatives of objective functions, while some optimization problems' objective functions have no derivatives. According to former research studies, some search directions are obtained using the quadratic hypothesis of objective functions. Based on derivatives, quadratic function assumptions, and directional derivatives, the computational formulas of numerical first-order partial derivatives, second-order partial derivatives, and numerical second-order mixed partial derivatives were constructed. Based on the coordinate transformation relation, a set of orthogonal vectors in the fixed coordinate system was established according to the optimization direction. A numerical algorithm was proposed, taking the second order approximation direction as an example. A large stepsize numerical algorithm based on coordinate transformation was proposed. Several algorithms were validated by an unconstrained optimization of the two-dimensional Rosenbrock objective function. The numerical second order approximation direction with the numerical mixed partial derivatives showed good results. Its calculated amount is 0.2843% of that of without second-order mixed partial derivative. In the process of rotating the local coordinate system 360°, because the objective function is more complex than the quadratic function, if the numerical direction derivative is used instead of the analytic partial derivative, the optimization direction varies with a range of 103.05°. Because theoretical error is in the numerical negative gradient direction, the calculation with the coordinate transformation is 94.71% less than the calculation without coordinate transformation. If there is no theoretical error in the numerical negative gradient direction or in the large-stepsize numerical optimization algorithm based on the coordinate transformation, the sawtooth phenomenon occurs. When each numerical mixed partial derivative takes more than one point, the optimization results cannot be improved. The numerical direction based on the quadratic hypothesis only requires the objective function to be obtained, but does not require derivability and does not take into account truncation error and rounding error. Thus, the application scopes of many optimization methods are extended. 展开更多
关键词 directional derivative NUMERICAL differential optimization method QUADRATIC function HYPOTHESIS
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DISCRETE GALERKIN METHOD FOR FRACTIONAL INTEGRO-DIFFERENTIAL EQUATIONS 被引量:1
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作者 P.MOKHTARY 《Acta Mathematica Scientia》 SCIE CSCD 2016年第2期560-578,共19页
In this article, we develop a fully Discrete Galerkin(DG) method for solving ini- tial value fractional integro-differential equations(FIDEs). We consider Generalized Jacobi polynomials(CJPs) with indexes corres... In this article, we develop a fully Discrete Galerkin(DG) method for solving ini- tial value fractional integro-differential equations(FIDEs). We consider Generalized Jacobi polynomials(CJPs) with indexes corresponding to the number of homogeneous initial conditions as natural basis functions for the approximate solution. The fractional derivatives are used in the Caputo sense. The numerical solvability of algebraic system obtained from implementation of proposed method for a special case of FIDEs is investigated. We also provide a suitable convergence analysis to approximate solutions under a more general regularity assumption on the exact solution. Numerical results are presented to demonstrate the effectiveness of the proposed method. 展开更多
关键词 Fractional integro-differential equation(FIDE) Discrete Galerkin(DG) generalized Jacobi Polynomials(GJPs) Caputo derivative
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ONLINE REGULARIZED GENERALIZED GRADIENT CLASSIFICATION ALGORITHMS
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作者 Leilei Zhang Baohui Sheng Jianli Wang 《Analysis in Theory and Applications》 2010年第3期278-300,共23页
This paper considers online classification learning algorithms for regularized classification schemes with generalized gradient. A novel capacity independent approach is presented. It verifies the strong convergence o... This paper considers online classification learning algorithms for regularized classification schemes with generalized gradient. A novel capacity independent approach is presented. It verifies the strong convergence of sizes and yields satisfactory convergence rates for polynomially decaying step sizes. Compared with the gradient schemes, this al- gorithm needs only less additional assumptions on the loss function and derives a stronger result with respect to the choice of step sizes and the regularization parameters. 展开更多
关键词 online learning algorithm reproducing kernel Hilbert space generalized gra-dient Clarke's directional derivative learning rate
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不平行方向导数下的二元函数全微分
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作者 潘璐璐 叶正麟 《高等数学研究》 2024年第2期8-10,共3页
通过利用线性代数中自变量空间的基变换方法,推演出二元函数全微分的两个方向不平行的方向导数的线性组合表示,然后在自变量空间的一般可逆变换下推演出全微分的这种表示,推广了二元函数全微分的表示形式,并解释了其几何意义.
关键词 全微分 方向导数 线性代数 基变换
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一类具有推广的Caputo分数阶导数的微分方程的Ulam稳定性
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作者 张玲玲 王森 +1 位作者 张孝锋 周先锋 《应用数学》 北大核心 2024年第3期847-855,共9页
本文研究一类具有推广的Caputo分数阶导数的微分方程,推广的Caputo分数阶导数可由Conformable导数与经典的Caputo导数结合而得或是推广的分数阶算子.我们利用拉普拉斯变换研究了线性方程的Ulam-Hyers稳定性,分别利用Banach不动点定理和G... 本文研究一类具有推广的Caputo分数阶导数的微分方程,推广的Caputo分数阶导数可由Conformable导数与经典的Caputo导数结合而得或是推广的分数阶算子.我们利用拉普拉斯变换研究了线性方程的Ulam-Hyers稳定性,分别利用Banach不动点定理和Guonwall不等式研究了非线性方程解的存在唯一性和Ulam-Hyers-Rassis稳定性,获得了几个充分条件的定理,并给出一个例子作为所得结果的应用. 展开更多
关键词 Ulam稳定性 推广的Caputo分数阶导数 微分方程
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关于多元函数在一点连续性的思考与探究
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作者 张岩 《吕梁学院学报》 2024年第2期4-7,共4页
本文通过引入多元函数“关于x(或y)连续”以及“沿方向l连续”的概念,使多元微分学的知识点间形成逻辑闭环,使学生对多元微分学的理解与一元微分学的认知形成对应.
关键词 一元微分 多元微分 偏导数 方向导数
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利用Grümwald-Letnikov分数阶方向导数的图像增强方法 被引量:12
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作者 牛为华 孟建良 +1 位作者 崔克彬 王琳倩 《计算机辅助设计与图形学学报》 EI CSCD 北大核心 2016年第1期129-137,共9页
针对传统图像增强过程中存在丢失细节且容易出现欠增强或过增强的不足,提出一种基于Grümwald-Letnikov分数阶方向导数的图像增强方法 .该方法利用基本分数阶微积分的形式,根据数字图像的自相关性将Grümwald-Letnikov分数阶微... 针对传统图像增强过程中存在丢失细节且容易出现欠增强或过增强的不足,提出一种基于Grümwald-Letnikov分数阶方向导数的图像增强方法 .该方法利用基本分数阶微积分的形式,根据数字图像的自相关性将Grümwald-Letnikov分数阶微分与方向导数相结合,定义了新的微分增强模板系数,构造了各个方向的分数阶微分卷积模板,并将其应用于图像增强.实验结果表明,文中方法在对图像高频信息进行提升的同时能够有效地提升图像的中低频信息,使得图像的纹理细节得到增强,特别是边缘信息更加突出,图像的清晰度及信息熵等图像质量指标有明显的提高,增强后图像的视觉效果良好. 展开更多
关键词 Grümwald-Letnikov微分 方向导数 图像增强 微分卷积模板 边界点
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兔骨髓基质干细胞的体外培养及生物学活性研究 被引量:5
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作者 张晨 王坤正 +3 位作者 强辉 时志斌 党晓谦 黄向辉 《西安交通大学学报(医学版)》 CAS CSCD 北大核心 2010年第2期138-142,共5页
目的体外分离培养、鉴定兔骨髓基质干细胞(BMSCs)并探讨其分化潜能。方法应用密度梯度离心联合贴壁筛选的方法,体外分离培养兔骨髓来源的骨髓基质干细胞,培养过程中倒置显微镜下观察其生物学特性,HE染色和CD34、CD44免疫组织化学染色行... 目的体外分离培养、鉴定兔骨髓基质干细胞(BMSCs)并探讨其分化潜能。方法应用密度梯度离心联合贴壁筛选的方法,体外分离培养兔骨髓来源的骨髓基质干细胞,培养过程中倒置显微镜下观察其生物学特性,HE染色和CD34、CD44免疫组织化学染色行细胞学鉴定;应用体外成骨与成脂诱导分化检测其生物学活性。结果体外实验成功分离培养兔BMSCs,HE染色显示细胞均一性好;CD44强阳性表达,CD34阴性表达。诱导成骨结果显示BMSCs具有较强的成骨活性,ALP染色阳性;成脂诱导结果显示BMSCs具有较强的成脂活性,油红"O"脂肪染色阳性。结论BMSCs体外具有潜在的多向分化能力。 展开更多
关键词 骨髓基质干细胞 细胞培养 多向分化
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一类非线性算子的不动点定理及其应用 被引量:4
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作者 林壮鹏 徐远通 郭志明 《中山大学学报(自然科学版)》 CAS CSCD 北大核心 2000年第6期26-29,共4页
利用方向导数及Banach空间常微分方程理论研究一类非线性算子的不动点的存在唯一性 ,推广了著名的Banach压缩映象原理 .同时还给出它们在一些重要的非线性问题上的应用 .
关键词 方向导数 BANACH空间常微分方程 不动点
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巴黎期权的PDE定价及隐性差分方法研究 被引量:6
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作者 宋斌 周湛满 +1 位作者 魏琳 张冰洁 《系统工程学报》 CSCD 北大核心 2013年第6期764-774,共11页
在假设标的资产价格服从几何布朗运动的基础上,指出了已有文献中关于巴黎期权的偏微分方程(PDE)定价方法存在的问题,给出了正确的边界条件和终值条件,利用方向导数将该三维PDE降为二维PDE.进而运用隐性差分方法为巴黎期权定价.并将其与... 在假设标的资产价格服从几何布朗运动的基础上,指出了已有文献中关于巴黎期权的偏微分方程(PDE)定价方法存在的问题,给出了正确的边界条件和终值条件,利用方向导数将该三维PDE降为二维PDE.进而运用隐性差分方法为巴黎期权定价.并将其与显性差分方法比较,数值结果表明,隐性差分方法绝对稳定,收敛速度快且计算成本较低. 展开更多
关键词 巴黎期权 偏微分方程 方向导数 隐性差分 绝对稳定性
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(h,)-Lipschitz函数及其广义方向导数和广义梯度 被引量:7
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作者 徐义红 刘三阳 《数学物理学报(A辑)》 CSCD 北大核心 2006年第2期212-222,共11页
借助于Ben—Tal广义代数运算引进了一种新的函数-(h,)-Lipschitz函数.讨论了它与Lipschitz函数之间的关系,给出了它的广义方向导数和广义梯度,得到了它们的若干性质.作为应用,给出了广义方向导数与切锥之间的关系。
关键词 (h φ)-Lipschitz函数 广义方向导数 广义梯度
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广义微分中值定理 被引量:3
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作者 刘元会 常安定 邓秋霞 《纺织高校基础科学学报》 CAS 2003年第4期294-297,共4页
对于k阶可导函数,利用拉格朗日中值定理,证明了函数的k阶导数与函数值之间的关系;对于s阶可导函数(s>k),证明了函数的s-k阶导数值与函数的s阶导数之间的关系.给出了常见的k=2,k=3,k=4对应的定理及其证明.
关键词 高阶导数 中值定理 微分
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兔骨髓间充质干细胞的分离、培养及鉴定 被引量:11
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作者 刘伟 陈剑 +1 位作者 宋佳 宋滇文 《中国实验诊断学》 2013年第8期1366-1369,共4页
目的探讨兔骨髓间充质干细胞分离、培养和鉴定的方法。方法全骨髓贴壁法提取兔骨髓中的间充质干细胞,流式细胞术检测细胞表面分子CD14、CD29、CD34、CD44、CD45和CD90等标志的表达以及不同代次兔BM-SCsDNA含量。通过定向分化检测兔BMSC... 目的探讨兔骨髓间充质干细胞分离、培养和鉴定的方法。方法全骨髓贴壁法提取兔骨髓中的间充质干细胞,流式细胞术检测细胞表面分子CD14、CD29、CD34、CD44、CD45和CD90等标志的表达以及不同代次兔BM-SCsDNA含量。通过定向分化检测兔BMSCs的多向分化潜能。结果兔骨髓间充质干细胞呈形态较为均一的小梭形、克隆样生长。流式细胞术检测结果显示,传代至第12代和20代的兔骨髓间充质干细胞检测对数生长期细胞的DNA含量结果显示细胞为正常二倍体细胞,无明显变异。细胞表面表达CD29(61.71%)、CD44(60.2%),不表达CD14(0.4%)、CD34(0.34%)、CD45(0.64%)和CD90(0.04%)。兔BMSCs的定向分化结果显示其可向成骨细胞、脂肪细胞及成软骨细胞分化。结论成功获得具有多向分化潜能的兔骨髓间充质干细胞,其具有特定的细胞表面抗原,具有容易获取、增殖能力强等特点,是优良的组织工程种子细胞。 展开更多
关键词 骨髓间充质干细胞 细胞表型 多向分化
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非线性随机种群系统的最优控制 被引量:5
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作者 戴晓娟 张启敏 《昆明理工大学学报(理工版)》 CAS 北大核心 2009年第3期100-104,共5页
讨论一类具有空间扩散的非线性随机种群系统最优控制问题,得到了当外界环境对种群系统产生影响的条件下,控制为最优的必要条件以及由积分-微分方程和变分不等式构成的最优性组,结论是确定性种群系统的扩展.
关键词 种群系统 积分-偏微分方程 方向导数
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BDNF和IGF-1对皮层神经干细胞向神经元定向分化的影响 被引量:3
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作者 沈雪莉 李花 石玉秀 《中国医科大学学报》 CAS CSCD 北大核心 2005年第6期513-515,共3页
目的:探讨脑源性神经营养因子(BDNF)和胰岛素样生长因子1(IGF-1)对大鼠皮层神经干细胞向神经元定向分化的影响。方法:采用细胞培养技术、免疫细胞化学方法观察BDNF和IGF-1对皮层神经干细胞向神经元定向分化的影响。结果:皮层神经干细胞... 目的:探讨脑源性神经营养因子(BDNF)和胰岛素样生长因子1(IGF-1)对大鼠皮层神经干细胞向神经元定向分化的影响。方法:采用细胞培养技术、免疫细胞化学方法观察BDNF和IGF-1对皮层神经干细胞向神经元定向分化的影响。结果:皮层神经干细胞在去除丝裂原后开始进行分化,至7 d可分化为成熟神经元,神经元特异烯醇化酶(NSE)明显阳性。BDNF、IGF-1组与对照组相比,定向分化为神经元的比率增加21.7%(P<0.01)。结论:BDNF,IGF-1对皮层神经干细胞向神经元的定向分化具有促进作用。 展开更多
关键词 神经干细胞 定向分化 神经元 脑源性神经营养因子 胰岛素样生长因子
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