逼近地

The powerful function of a new computer language MATLAB, produced by the America Mathworks company, is the mathematical software system for the calculation in science engineering. It can efficiently solve problems in science and engineering such as numerical linear hypercomplex system, digital approximation, optimization, numerical quadrature etc. It also has characters of beautiful interface and convenience for users.

MATLAB是Mathworks公司推出的适用於科学和工程计算的数学软件系统，可高效地解决数值线性代数、微分方程数值解、数值逼近、最优化、数值积分等科学和工程问题，且具有可视化图形处理、使用方便、开放式多功能於一体的新一代计算机语言。

At the same time, the simple independent and identically distributed GGD models can be more robust and efficient than subband-dependent GGD models.

研究表明，自然图像多重子带的边缘分布能充分地反映其特征，而广义高斯分布建模在变换域中被认为是对自然图像最逼近和最成功的边缘分布建模方式。

Firstly, This paper processes geometry filtration based on character of orbit's apogee and perigee after orbit model is analyzed and based. Secondly Space Debris is separated into two kinds, coplanar and not coplanar according as location interrelation of target and debris. In Dynamic filtration's processing, considering prediction time limit and orbit perturbation, secular effects which have increaser effect is considered so that some need catching danger time point is appeased, some law about time when target and debris pass intersectant line each other is inferred, when debris and object are in different plane and some similar law also is inferred otherwise. The time list is arithmetical progression. These laws can improve calculation efficiency remarkably; Lastly orbit predict is a course approaching least distance. Danger time point in the last step become beginning time point from which debris and object's position and velocity are calculated by SXP4 Model which is an analytic model.By result, determine that relative movement trend is closer or apart, farther calculate the interval apart from time when predictive least relative distance occurs. Least relative distance and time when least distance occurs is calculated finally. It is a fast approach course adopting varied interval.

本文在分析、建立轨道摄动计算模型的基础上，首先采用基于轨道远、近地点特征对大量编目在册的空间碎片进行初步几何静态筛选，然后根据碎片与目标轨道面的相对位置特点把碎片分为异面与准共面两种情况以进行动态筛选，在筛选过程中考虑到预报时限长度和轨道摄动影响，引入了轨道摄动中具有积累效应的长期项以满足危险时间点的捕捉要求，利用了长期项摄动变化线性的特点导出了碎片与目标异面情况下各自过交线的时间序列成准等差数列的规律性和准共面情况下类似的规律性，从而显著地提高了前期轨道筛选的计算效率；最后对剩余危险碎片和目标飞行器利用SXP4轨道预报模型在前期轨道筛选的基础上以各个危险探测时间点为预报的时间起点，并根据预报计算结果，分析目标和碎片在该时间点的运动趋势是相互远离还是相互接近，推出预计最小相对距离发生时刻相对此刻的时间长度，得到其随时间变化的局部最小相对距离以及危险距离发生的时刻和相对速度，这是一个采用变时间步长、快速逼近最小相对距离的过程。

Considering on the monotonously increasing character of the displacement series in underground engineering, a new integrated intelligent method for displacement prediction is proposed.

针对地下工程变形监测中位移单调增长的特性，根据位移分解原理，采用灰色系统提取位移序列的趋势，用基于免疫进化规划的进化神经网络逼近偏差序列，提出了变形预测的集成智能建模方法，很好地解决了地下工程变形预测的难题。

Ned Ordway lea ned forward, close to Inez , his face aggressive

内德·奥德威探身向前，气势汹汹地逼近伊内兹。

Reusing iterative information ,an approximate inverse function is constructed byinverse interpolation.

重复使用迭代信息反插值构造逆函数的近似，一方面较只使用单点信息能更好地逼近隐式函数，另一方面直接得到显式近似解。

It is predominant that this software engross a lot of system resources, and the track of the knifepoint can draw up the track of the drawing commendably.

本文采用的插补算法简便科学，只耗用相当少的系统资源，刀具轨迹能很好地逼近原图形轨迹。

We also develope the corresponding spherical harmonic-generalized Laguerre polynomial mixed spectral method and apply them successfully to computation of three dimensional problems, exterior problems and nonlinear problems.

在第二章中，我们提出了一类新的广义Laguerre多项式正交逼近，其特点是适用于更多问题并能更好地拟合微分方程真解在无穷远处的性态，从而提高了计算精度。

Moreover, simulation results show that it has a better performance in terms of the probability density functions of the envelope and phase, the level crossing rate, and the average fade duration than the previous methods.

仿真结果表明，改进后的方法生成的复随机过程的幅度、相位的概率密度函数及平均电平通过率、平均衰落持续时间能更好地逼近理论参考值。

In this article, the existence and uniqueness of the generalized solution of this boundary value problem are discussed, the existence and convergence of Galerkin's approximate solution is proved, and Linear dependence of the the error bound on M~2/(1-M~2) is also proved, where M is Ma...

本文证明了这类方程弱解的存在和Galerkin逼近解的存在和收敛，并且还给出了有限元解的误差估计，指出误差界线性地依赖于M~2/(1—M~2)。M为马赫数。也就是说，当流速接近音速时，有限元解的误差将无法控制。

I am sure after a few weeks of adaptation and familiarization I will have no difficulty in functioning on a daily basis in an English speaking society or in participating fully in graduate studies.

在大学的三年的学习生活不仅给予我自身的充实，更重要的是磨练和培养了我较强的自觉能力和严谨，踏实的作风以及不怕困难的精神，对未来充满了信心！

As the first volcanoes erupted, one of the gases that bellowed out was steam.

在第一批火山喷发时，喷出的气体之一就是水蒸汽。