查询词典 nine point finite difference scheme

We constructed a finite volume scheme of fifth order Hermite type with high accuracy for twopoint boundary value problems, choosing trial and test spaces as the fifthorder finite element space of Hermite type and the piecewise linear function space respectively. We didn't use higher derivatives as interpolation conditions, which is the same as the thirdorder finite element of Hermite type, but the scheme obtained had higher accuracy.

构造求解两点边值问题的一种Hermite型五次元高精度有限体积法，其中试探函数空间取Hermite型五次有限元空间，与Hermite型三次元相同，未引入更高阶导数作为插值条件，检验函数空间取分段线性函数空间，这样构造的格式求解精度更高。

The model incorporated with the aerodynamical urban canopy scheme is better to simulate the wind field on the urban areas.The conclusions are drawn by the comparisons between the simulation results of the building drag scheme and the aerodynamical urban canopy scheme in a real town: the simulated wind speed with the aerodynamical canopy scheme on the town areas is always lower than that on the surrounding rural areas, but that with the other scheme is not so.

分别采用建筑物拖曳法与建筑物动力冠层方案对一个实际小规模城市进行模拟试验，分析表明引入建筑物动力冠层方案可以模拟出小规模城市地区水平风速偏低的现象；还可以模拟出城市地区建筑物动力作用对湍流活动的影响；对湍流动能模拟结果表明比较符合实际分布情形。

In Gregory scheme, not only the importance of the moist static energy is taken into account, but also the common difficulty of the moist convective adjustment scheme, the determination of the temperature profile, is obviated. At the same time, it can give the vertical profile of the apparent heat source Q〓 and apparent moisture sink Q〓. Gregory scheme has the clear physical image that includes the cumulus updrafts, cumulus downdrafts,cumulus induced subsidence in the environmental air, entrainment,detrainment and evaporation. In addition, the interaction between the cumulus and the environment is described by one-dimensional bulk model. It is simpler than the Arakawa-Schubert scheme and has no difficult to decide the spectrum of clouds accurately.It is propitious to operational use because of its simple calculation. Finally, Gregory scheme is not only suitable for moist convection of all types, but also for dry convection.

在该方案中，既强调了湿静力能能量的重要性，又回避了给定临界温度廓线的困难，并且还能给出真实的视热源Q1，视水汽汇Q2的垂直廓线；同时Gregory方案又具有很清晰的物理图象—积云中的上升运动，下沉运动，环境中的补偿下沉运动，以及卷入，卷出和蒸发等；此外，Gregory方案用总体云群模式来描述云与环境的相互作用，比型积云参数化方案简单，它避开了型方案中云谱需要精确设置的麻烦问题，计算容易，简便；最后，Gregory方案在湿对流中适用于浅，深，中不同的对流深度，并且也适用于干对流过程。

Secure communication scheme based on chaotic synchronization is an entirely new secure communication scheme. Pecora and Carroll propose secure communication scheme based on chaotic synchronization first in 1990. The scheme makes use of the good characteristic of chaotic signals, and has high security. Lots of papers improve on the scheme after it has been proposed.

基于混沌同步的保密通信方案是一种全新的保密通信方式。1990年，Pecora-Carroll首先提出了基于混沌同步的保密通信方案，方案利用了混沌信号所具有的优良特性，具有很高的安全性，之后又有很多文献对该方案进行了改进。

An improved shceme for the old double-way authentication access control scheme based on Harns digital signature is proposed. The new double-way authentication protocol of the improved access control scheme can prevent man-in-the-middle attack and replay attack. After strict formal analysis with BAN logic, the result have proved that the authentication protocol is secure. The improved access control scheme is realized by the mode of single-key-lock-pair. Under new access control scheme, user can own several kinds of access right upon one file under the new scheme without the supposition that the access rights is increase by degrees, and the possibility of overflow problem is significantly reduced by our new method

作为对原双向认证访问控制方案的改进，改进后的双向身份认证协议可以很好的抵抗中间人攻击和重放攻击，经过严密的BAN逻辑形式分析和论证，结果表明该协议是安全的；改进后的访问控制方案用单钥-锁对方案实现，除保持了一般单钥-锁对方案的良好动态特性外，在不需要访问权限递增假设下，实现了用户对文件的多种访问控制权限，并大大减小了溢出问题的发生可能

This paper is devoted to solving linear saddle point problems, Specifically, We consider nonsymmetric systems, written as usual in block form, where the upper left block is an invertible linear operator with positive definite symmetric part. Such saddle point problems arise, for example, in certain finite element and finite difference discretizations of NavierStokes equations, Oseen equations, and mixed finite element discretization of second order convection-diffusion problems.

中文题名求解鞍点问题的迭代方法副题名外文题名论文作者冯丽红导师曹志浩教授学科专业计算数学研究领域\研究方向学位级别博士学位授予单位复旦大学学位授予日期2002 论文页码总数87页关键词鞍点问题迭代方法网格离散线性方程组馆藏号BSLW /2003 /O241 /15 论文针对鞍点问题的求解分析了一些典型的快速算法。

In order to solve parabolic equation of heat conduction with interval parameters, the regions of space are discretized by finite elements and the regions of time are discretized by finite difference. The interval finite element method based on the element is established via the combination of interval analysis and the traditional finite element method.

对具有区间参数的热传导抛物型方程的求解，在空间域上利用有限单元离散，在时间域上利用差分离散，将区间分析和常规的有限元法相结合，建立了求解不确定温度场的基于单元的区间有限元方法。

Finite element discretization was carried out on the mathematical model to get a fully coupled finite element equation with the parameters of element nodal displacement and element nodal pore pressure as unknown variables. Finally, the transient nonlinear finite element equation in incremental form for reservoir fluid-solid coupling is obtained by means of time discretization in implicit difference scheme.

基于与微分方程等价的加权余量公式，在空间域采用有限元离散，对时间域进行隐式差分格式离散，导出了以单元节点位移和单元节点孔隙压力为未知量的储层流固耦合的非线性有限元增量方程。

Firstly, the fully discrete standard finite element Galerkin method and the nonlinear finite element Galerkin method and the modified finite element Galerkin method in which time is discretized by the Euler implicit difference scheme are considered, and the - and - global relative errors and CPU time corresponding to the SG method, the NG method and the MNG method are computed respectively.

首先，对于全离散(时间离散是欧拉显式格式)标准有限元Galerkin方法和非线性有限元Galerkin方法以及修正有限元非线性Galerkin方法，分别进行数值计算，并比较了三种算法的计算解与精确解的误差估计及所耗费的CPU时间，结果验证了MNG方法要优于NG方法，而NG方法又优于SG方法。

In order to get the numerical solution, the paper devises a three hierarchic implicit scheme which eliminates the strict restriction of explicit scheme, thus, it can be used in more areas. By using the energy estimation method, the convergence and stability of the difference scheme are proved and the scheme is second order convergence for time and space.

对求解方程构造了一个三层隐式差分格式，消除了显格式的稳定性对计算步长的严格限制，使之适用范围更广，并用能量估计的方法严格证明了差分格式的收敛性与稳定性，该格式对于时间和空间均具有二阶收敛性。

I want to be a big fish in a small pond.

我要做一条在小池塘里的大鱼。

While the software functioned well, we did not feel the same about their customer support!

虽然该软件运行良好，我们没有同样的感觉他们的客户支持！