查询词典 finite difference approximation

The use of the rational approximation and the Rayleigh quotient leads to that the quality of power-series expansion is significantly improved and the range of approximation is extended with a few of additional operation counts.

在只增加少许计算量的情况下，利用向量值函数的有理逼近方法以及 Rayleigh 商来改善摄动解的逼近质量并扩大其逼近范围。

Some new basic concepts are proposed in this paper, including the approximation space of generalization, rough approximation axiom, disturbance set axiom, classification principle of rough set, principle of nondeterministic even set, principle classification, bit quantum symmetric classification, of concentration, game classification, quantum logic incomparable set, bit space set, protocol relation, rough set function of protocol relation, rough classification algebra, rough simple algebra, etc., and a guess is also proposed.

提出了广义近似空间、粗近似公理、干扰集公理、粗糙集的分类原则、粗选原则、不确定偶集原则、精选原则、对策分类、量子逻辑分类、bit量子对称分类、不可比集、bit空间集、协议关系、粗糙集函数、粗糙分类代数和粗糙单代数等基本概念，并提出了一个猜想；展示了一些新观点；基于协议关系构造了粗糙商代数和粗糙子代数，给出了回避-归并算法及算例。

Since Bloch's Theorem applies only to periodic potentials, and since unceasing random movements of atoms in a crystal disrupt periodicity, Bloch's Theorem is only an approximation, but it has proven to be a tremendously valuable approximation, without which most solid-state physics analysis would be intractable.

由于布洛赫定理仅对周期性势场的情况严格成立，而由于实际的晶体中不可避免的有各种缺陷或者原子相对于平衡位置的位移，所以布洛赫定理对于实际晶体来说只是一个近似。但是布洛赫定理对于固体物理的研究不可或缺。

Spherical approximation triangle demonstration tenets : first approximation using regular t...

三角形逼近球体演示原理：先用正三角形逼近绘出20面体，然后递归分割，把每个面分割为4个三角形，此以来逼近球体。

Spherical approximation triangle demonstration tenets : first approximation using regular tria...

三角形逼近球体演示原理：先用正三角形逼近绘出20面体，然后递归分割，把每个面分割为4个三角形，此以来逼近球体。

The algorithm provided in this text is general and it can be expaned to other field, such as spline approximation, function approximation and the curve fitting.

本文提供的逼近算法具有一般性，可将其推广到其它领域，如样条逼近、函数逼近、曲线拟合。

For this, another tool-simultaneous perturbation stochastic approximation for solving optimization problems is introduced. In fact, SPSA is a simple, easily implemented and efficient stochastic approximation algorithm.

本文将 SPSA算法作为一种快速局部优化方法并将其和遗传算法的整体搜索策略结合起来，提出一种解决多目标优化问题的随机梯度遗传算法，对新算法的执行策略进行了认真的设计。

Model of adaptive session is analyzed, and available bandwidth' future estimation is achieved. The fuzzy nonlinear approximation of immune' suppresser is fulfilled by fuzzy rules' self-tuning with self-tuning factor in full domain. Then, in order to improve the traditional PID algorithm fuzzy nonlinear approximation is combined with immune feedback mechanism to adjust PID factors during the course of multimedia transmission.

分析多媒体流自适应节模型，实现IP网络可用带宽的预估计，采用全论域范围内带有自调整因子的模糊规则自调整方法进行免疫抑制量的模糊非线性逼近，并与免疫反馈机理相结合，多媒体流传输过程中自适应整定PID参数以改进传统PID算法。

Just like we can think of the Gregorian year as an approximation to the tropical year, we can think of the nian as an approximation to the su'.

就像格里高利历中的"年"是对回归年的近似，我们可以认为"年"是对"岁"的近似。

In this paper, a region approximation idea that means using a "fat curve" with a width to approximate the offset curve is proposed, and a complete set of algorithms to approximate offset curve using disk Bézier curve are given and implemented. In the algorithms, the optimal and uniform approximate curve of the offset curve as the central curve of the Disk Bézier curve is found by using Remez method, and then the upper optimal and uniform approximation principle is proposed to compute the error radius function of the Disk Bézier curve. Thus, the whole Disk Bézier curve can be obtained. In the end of this paper, the approximate effect of the Disk Bézier curve is not only analyzed and assessed, but also some specific examples are provided.

提出用一条带宽度的"胖曲线"来逼近上述等距曲线的区域逼近思想，并建立与实现了圆域Bézier曲线等距逼近的整套算法，包括应用Remez方法求出等距曲线的最佳一致逼近曲线作为圆域Bézier曲线的中心曲线，提出上控最佳一致逼近的原理求出圆域Bézier曲线的误差半径函数，以及确定整条圆域Bézier曲线，最后还对该圆域Bézier逼近的效果做了分析和考核，并给出了一些具体实例。

The French are not suggesting a new EU treaty, but they have plenty of other wheezes.

法国人并不是在建议签署一个新的欧盟条约，但他们有许多其他的阴谋。

This letter was written by my brother.

这封信是我弟弟写的。