查询词典 difference equation

The analysis in theory proves that cellular automaton is equal with a stochastic process that described by stochastic difference equations. The primary differential equation is expectation of this stochastic process. And its variance function is controllable. These results show that cellular automata are in agreement with primary differential equation in the statistical sense.

理论分析证明：该方法设计的细胞自动机等价于一个可用随机差分方程描述的随机过程，该随机过程以原微分方程为期望函数，并且，其方差函数是可控的，表明细胞自动机和原微分方程在统计意义上是一致的。

It's proved that the long duration response is stable under stationary random excitation, when the mean equation of the temperature in all parts of heat conductor shows no difference with the heat conduction differential equation under classical stationary heat conduction condition.

研究表明，在平稳随机激励下，导热系统的长时间响应也是平稳的。

In Chapter 2, starting from the basic fractional ordinary differential equations,weapply a high order approximation of fractional derivative advanced by Lubich to frac-tional differential equation, construct a high numerical difference scheme to solve thefractional differential equation, present error analysis of the algorithms theoretically,and prove the consistency ,convergency and stability.

接下来的第二章中，首先从基本的分数阶常微分方程出发，对Lubich提出的一个关于分数阶导数的高阶近似，将其应用于分数阶微分方程，构造高阶数值差分格式来进行分数阶微分方程的数值求解，并在理论上给出这一算法的误差分析，证明了它的相容性，收敛性和稳定性。

He difference between quantities equation and numerical value equation is analyzed in detail.

从定义、概念、应用以及相互关系等方面对量方程式和数值方程式进行了分析对比，指出了正确使用这两种方程式的重要性和方法。

Among used machine learning methods, the gradient descent method is widely used to train various classifiers, such as Back-propagation neural network and linear text classifier. However, the gradient descent method is easily trapped into a local minimum and slowly converges. Thus, this study presents a gradient forecasting search method based on prediction methods to enhance the performance of the gradient descent method in order to develop a more efficient and precise machine learning method for Web mining.However, a prediction method with few sample data items and precise forecasting ability is a key issue to the gradient forecasting search method. Applying statistic-based prediction methods to implement GFSM is unsuitable because they require a large number of data items to model a prediction model. In the contrast with statistic-based prediction methods, GM(1,1) grey prediction model does not need a large number of data items to build a prediction model, and it has low computational load. However, the original GM(1,1) grey prediction model uses a mathematical hypothesis and approximation to transform a continuous differential equation into a discrete difference equation in order to model a forecasting model.

其中梯度法是一个最常被使用来实现机器学习的方法之一，然而梯度法具有学习速度慢以及容易陷入局部最佳解的缺点，因此，本研究提出一个梯度预测搜寻法则(gradient forecasting search method， GFSM)来改善传统梯度法的缺点，用来提升一些以梯度学习法则为基础的分类器在资讯探勘上的效率与正确性；而一个所需资料量少、计算复杂度低且精确的预测模型是梯度预测搜寻法能否有效进行最佳解搜寻之关键因素，传统统计为基础之预测方法的缺点是需要较大量的数据进行预测，因此计算复杂度高，灰色预测模型具有建模资料少且计算复杂度低等优点，然而灰色预测理论以连续之微分方程式为基础，并且透过一些数学上的假设与近似，将连续之微分方程式转换成离散之差分方程式来对离散型资料进行建模及预测，这样的作法不尽合理，且缺乏数学理论上的完备性，因为在转换过程中已经造成建模上的误差，且建模过程仅考虑相邻的两个资料点关系，无法正确反应数列未来的变化趋势。

The finite difference method is employed to discretize the governing equations and the projection method is used to derive a pressure Poisson equation that can ensure the satisfaction of continuity equation.

控制方程式采用有限差分法求解，并利用投影法导出压力的波松方程，使得能自动满足连续方程式。

In the simplified model, the governing equation of heat conduction is discretized using implicit finite difference method, and the computational domain is discretized using cell centered scheme, and the solution of Maxwell equation is used to determine the distribution of the internal heating sources.

使用的简化模型中热传导方程的离散采用隐式差分法、区域的离散采用内节点法，并以Maxwell方程的解确定内热源分布。

And we show that random walk model converges to the stable law of Lévy-Feller advection-dispersion equation by use of a properly scaled transition to vanish-ing space and time steps,We propose an explicit finite difference approximation for Lévy-Feller advection-dispersion equation.

第三章讨论描述服从某种稳定分布反常扩散的非对称空间分数阶对流-扩散方程——Lévy-Feller对流-扩散方程，首先利用Fourier变换和Laplace变换给出方程的基本解，然后利用Grünwald-Letnikov分数阶导数移位离散算子离散方程中的Riesz-Feller分数阶导数得到离散格式，证明此格式可以解释为离散随机游走模型，并且证明了当时间和空间步长以一定的比率同时趋于0时，所提出的离散随机游走模型收敛到Lévy-Feller对流-扩散过程的稳定分布。

Use of the finite difference method for Volterra equation here as a variable element of the equation, As the same...

用差分方法求解沃尔泰拉方程，此处为一个变元的方程，由于该方程同时含有微分和积分，一般求解有一定的困难。

In the first part we consider the convergence and stability of finite difference scheme for Landau-Lifshitz equation in one dimensions space and 2d radial symmetric Landau-Lifshitz equation.

在第一部分，我们研究一维Landau-Lifshitz方程非齐次边值问题和二维柱对称Landau-Lifshitz方程Neumann边值问题的有限差分格式。

You have to walk your own alk in this life.

次生中你必须走自己的路。

To start with, the thesis analyses ***ism in terms of the generic masculine words, word order and semantic derogation of women in greater detail.

论文首先从阳性词泛指，词序，词义的贬降等方面对英语中的性别歧视现象进行了详细的分析。