查询词典 backward difference operator

In this paper, a novel feature MFCC_FWD_BWD, which is based on forward-backward difference dynamic parameters, is presented to satisfy the requirement that the feature construction matrix is invertible for PMC.

本文首先提出了一种基于前后向差分动态参数的特征MFCC_FWD_BWD，该特征满足PMC对特征构造矩阵可逆的要求。

This thesis is divided into six parts. The first chapter is preface, the current status of research in the inverse problems for parabolic partial differential equations is reported; the second chapter is "regularization methods for numerical differentiation and their applications ", in this chapter we investigate many regularization methods from a viewpoint of regularization theory and algorithm, some applications in the inverse problems for parabolic partial differential equations are given; the third chapter is "spectral regularization methods". Based on Fourier analysis, within the framework of regularization theory, we apply the spectral methods to some ill-posed problems. Many numerical experiments are done in order to show the validity of the methods; the fourth chapter is devoted to wavelet dual least squares method and a revised wavelet method; in the fifth chapter,we combine finite difference method with method of lines and apply it to the backward heat conduction problem in time; in the sixth chapter "identification problems for unknown source ", the essence and the degree of two problems related to source identification are pointed out, at the same time, some numerical methods are reported.

本文分为六个部分，第一章前言简要分析了国内外抛物型偏微分方程反问题的研究现状；第二章数值微分的正则化及其应用从正则化理论和算法的角度出发，考察了许多正则化方法，还给出了数值微分在抛物型偏微分方程反问题的一些应用；第三章谱正则化方法是在Fourier分析的基础上，在一般正则化理论的框架下，给出了这种方法在各种不适定问题中的应用，数值实验表明谱方法是有效的；第四章研究了小波对偶最小二乘方法和改进的小波方法；第五章主要研究了有限差分方法结合线方法在时间反向热传导问题中的应用；第六章是未知源识别问题，主要指出了两类未知源问题的不适定程度和不适定本质，同时报告了一些数值方法。

Accordingly, region of relatively backward ministry of Chinese and Western is fostering region economy new point of growth, contractible region economy grows difference.

因此，相对落后的中西部地带在培育区域经济新增长点，缩小地区经济发展差距。。。

The difference for the convective and pressure terms is based on the flux vector splitting method developed by Van Leer, and the alternating forward/backward vertical line Gauss-Siedel relaxation algorithm is employed to solve the differenced equations.

对通量项和压力项用Van Leer发展的迎风方法进行矢通量分裂，对离散方程采用交替方向的垂直线Gauss-Seidel方法迭代求解。

In conclusion, the results of multilevel model analysis showed that the GERD score of resident in Wuhan was relatively higher and had significant difference with that in Guangzhou, however, that in Shanghai, Beijing and Xi\'an had no significant difference compared with that in Guangzhou. That is to say, the prevalence of GERD in Wuhan was relatively higher compared with the other four survey sites; the residents'health status more worse, the GERD score more higher, and the influence of health status on GERD score was also effected by the region difference between Wuhan and Guangzhou; residents lived in rural region with lower education level, worse spirit status were more likely to suffer from GERD; Moreover, those residents who had family history of GI tumors or other GI diseases, some anamneses (such as dyspepsia, gastritis, rheumatic arthritis), and some diseases (such as irritable bowel syndrome and aerophagia) were also more likely to report GERD. However, no significant association was found between GERD and some other factors in this survey, such as sex, age, etc.

总之，多水平模型分析结果显示，与广州相比，上海、北京和西安居民的GERD总评分没有明显的差异，而武汉居民的GERD总评分则相对较高，即表示武汉的GERD发病率在5个调查城市中相对较高；居民的总体健康状况越差，其GERD总评分越高，且其对GERD总评分的影响受到武汉与广州之间地域差异的影响；农村居民、文化程度越低、精神状况越差者更容易患GERD；另外，那些有胃肠道疾病或肿瘤家族史，既往患有胃炎、消化不良、风湿性关节炎，现患有肠易激综合征、吞气症的人，患GERD的可能性更大，而性别、年龄等因素，本研究未发现其与GERD有显著的关系。

The scattering properties of particles with different shape parameters are simulated respectively in the modes of reflection and refraction. Both in the modes of reflection and refraction, the phase difference of non-spherical particle's PDA signal is the unbiased estimate of the corresponding phase difference of ideal spherical particle, and the standard deviation of angle roughness scale on particle surface impacts little on the distribution of phase difference.

本文通过物理光学的方法分析了非理想球形粒子的散射特性，利用物理光学中的稳相点理论，导出了非理想球形粒子散射光的相位表达形式，分析了非理想球形粒子的形状对PDA信号相位及相位差的影响，建立了非理想球形粒子的尺寸分布与PDA信号相位差分布之间的关系。

To against an afterload of 1.96kPa(200mmH_2O), measure two groups of direct flow and antidromic flow, both begin with the pressure difference of 0mmH_2O, add more 20 mmH_2O every time ,measure three tines at each pressure difference, get the average value at each pressure difference.

测试分为顺向和逆向两组，在克服后负荷压强为1.96kPa(200mmH_2O)情况下，分别从0mmH_2O压力差开始，每隔20mmH_2O递增，测量通过静脉外间接人造瓣膜的生理盐水流量，每个压力差值测量3次，取平均值。

The structure of the execution organizations: Three kinds of differences were presented, including natural difference, functional difference between central and local organizations, and difference in division of decision-making.

一、在执行组织结构方面：呈现机关属性的先天差异、中央与地方的功能差异，以及事权划分的纠葛等三项分殊性。

Two new rules represented in equality for Demyanov difference: the Demyanov difference of summations of two pairs of convex compact complementary sets;the Demyanov difference of a set, which is the convex hull of finite number of convex compact sets, and a convex compact set complementary to these sets,are given.

为此给出了两个关于Demyanov差的新的用等式表述的运算法则：两个彼此互补的凸紧集对的和的Demyanov差，有限个凸紧集的凸包和与这些凸紧集正交互补的凸紧集的Demyanov差。

In chapter 5, we study necessary conditions for difference sets and we obtain the following: we proved that there are no nontrivial difference sets in dihedral group of order 4p〓, where p is a prime, d is a positive integer; we give a necessary condition for Hadamard difference sets in some group of order 4p〓, and completely solve a general case left in Dr.

在第五章中，我们研究了差集存在的必要条件。

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。