离散

Since the decimation of discrete time signals is similar to the sampling of continuous signals, it is also studied in the thesis.

鉴于对离散信号的抽取和对连续信号的采样非常相似，本文还把研究范围拓展到了对离散信号的抽取问题。

The equality of local and global supervisor, the decentralized supervision strategies to optimize the performance measures of globally decomposable tasks are given complete attention.

运用图论的观点，通过对两种无直接关联的DEDS模型的研究，得到一种全新的离散事件优化方法，克服了RW理论已有框架的不足，从而为复杂离散事件系统的多模型集成提供了一条简明的途径。

In a special case of 2 dimensional variables, the probability of the positive definitiveness of the discrete sample covariance matrix is given in term of sample size and variable dimension. Based on the results, the optimal sample size is provided in this thesis.

推出了离散型样本协方差矩阵正定的充要条件，得到了求离散型样本协方差矩阵正定概率的模型，建立了特殊情况下的抽样优化模型。

The combinatorial and delimitative algorithm of engineering structure design with different discrete set and its software system is introduced in this paper.

引 言 离散变量优化设计是指在优化设计过程中，设计变量的取值不是在某一范围内连续变化而是只能取某些符合一定条件的离散值。

The derivation course and the discrete scheme of the first model-Perona-Malik model have been expatiated on emphasis. One item of the P-M model is omitted in the P-M's discrete scheme, and the gradient magnitude is replaced by the absolute value of difference quotient.

Perona-Malik给出的离散格式是一种显式离散格式，这一格式的连续形式省略了原模型中的一项，且用差商的绝对值代替了梯度模。

Since the different dynamics methods such as Newton-Euler method, Lagrange's equations and other methods can be used to develop the dynamic equations of global system, the two different forms of the dynamic equations are ordinary differential equations and differential algebra equations.

通过结合有限段法和多体系统动力学离散时间传递矩阵法，形成了非线性梁有限段离散时间传递矩阵法，该方法保留了有限段法适用于几何非线性大变形分析、自动考虑动力刚度项等优势，又保留了DT-TMM-MS建模方便灵活的特点。

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 surface representation in discrete form and its differential computation are important issues in computer graphics and geometric design.

0引言一般来说，曲面的一阶微分量是指曲面的切平面方向和法向量，二阶微分量是指曲面的曲率等有关量·它们作为重要的曲面信息度量指标，在计算机图形学，机器人视觉和计算机辅助设计等领域发挥了重要的作用·传统的曲面是连续形式的参数曲面和隐式曲面，其微分量的计算已经有了较完备的方法·随着激光测距扫描等三维数据采样技术和硬件设备的长足进步，以及图形工业对任意拓扑结构光滑曲面造型的需求日益迫切，离散形式的曲面———细分曲面、网格曲面和点云曲面正在逐渐成为计算机图形学和几何设计领域的新宠·于是，对这种离散形式的曲面如何估

In Chapter three, we mainly discuss the numerical method of the one dimensional nonlinear Schr〓dinger equation

在第二章中，主要结果是讨论了一维非线性薛定谔方程的保结构离散化方法，采用谱方法给出了此方程的全离散计算格式。

In Chapter two, we discuss structure preserving discretization method for the one dimensional nonlinear Schr〓dinger equation with periodic boundary value condition by means of spectral method.

在第二章中，主要结果是讨论了一维非线性薛定谔方程的保结构离散化方法，采用谱方法给出了此方程的全离散计算格式。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。