变换

modern compute processors and systems have put many technologies into practice, while compliers make high-performance possible when these technologies are used.the tree-ssa optimization infrastructure in gcc supplies a powerful program analysis framework.the enhanced data dependence analysisinformation allows compliers to change the algorithm for widen locality .whereby the utilization ratio of the resources can be improved which leads to increasing throughput and higher performance.the study focuses on data dependence, matrix transform and cyclic transformation by analyzing their features,algorithm and performance and stating the status quo of gcc cyclic transformation whereby outlook of the study has been made.

现代的计算机处理器和计算机系统实现了很多先进技术，要利用这些技术更需要编译器的支持以取得高性能。 gcc中tree-ssa优化框架提供了一个功能强大的程序分析框架。增强的数据依赖分析信息允许编译器变换一个算法以取得更大的局部性，提高资源的利用率以增大吞吐量，提高性能。该文对数据依赖、矩阵变换、循环变换进行了研究，分析了它们的特点，算法和性能，陈述了gcc中循环变换的现状，对以后的研究做出了一定的展望。

Objective To study the power spectrum density of blood flow ultrasonic Doppler signal using wavelet analysis. Method Doppler signal of blood flow in human common carotid artery was studied with wavelet scalogram analysis, an affine smoothing Wigner Ville transform with a constant "Q" character. Result Wavelet scalogram of blood flow ultrasonic signal had a higher distinguishability than STFT spectrogram in the low frequency portion, but had poorer decussation terms than spectrogram.

对于平稳信号的处理工具仍然是Fourier变换，但是，在实际应用中的绝大多数信号是非平稳的，现在看来处理非平稳信号的主要工具将是小波变换，这主要是因为传统的Fourier变换分析信号时，时间和频率分辨率精度是固定不变的，而利用小波变换分析信号，在信号高频段时间分辨率精度也较高，在信号低频段频率分辨率精度较高，这很符合非平稳信号的特点。

In Two-Transistor Flyback Converter circuit, a power semiconductor device in Flyback Converting circuit has been replaced by two power semiconductor devices which parallel connected with an ultra-fast diode with soft recovery characteristics. Two-Transistor Flyback Converter can reduce greatly the switching stress of the power switch and does not need to degausser, suitable for high input voltage Switching Power Supply.

反激变换是从Buck-Boost变换演变而来的，将反激变换电路中的单个功率开关管用两个替代，并在每个功率开关管上并联一十箝啦的快恢复二极管而形成的双晶体管反激变换电路，能大大降低功率开关管承受的开关应力，且不需要消磁电路，非常适用于高输入电压的开关电源。

We can take Fourier transformation or Laplace transformation towards try to of square distance both ends according to the their lines property, differential calculus property and integral calculus property, its conversion for act for of elephant function square distance, from this algebra square the distance beg an elephant function, then take Fourier negative transformation or Laplace negative transformation have to originally square distance of solution.

我们可以根据他们的线性性质，微分性质和积分性质，对欲求的方程两端取Fourier变换或Laplace变换，将其转化为象函数的代理方程，由这个代数方程求出象函数，然后再取Fourier逆变换或Laplace逆变换就得出原来方程的解。

For the diffractive optical element realizing beam shaping in the fractional Fourier transform domain,the transform matrix calculated by the discrete sampling points was compared with that calculated by the Fresnel integral,and the discretization error of the intensity distribution on the output plane was qualitatively obtained.

针对分数傅里叶变换衍射光学光束整形器件，比较了按离散点与按菲涅耳积分计算得到的变换矩阵间的差距，从中分析得出按离散点计算的变换矩阵引入的离散化误差与分数傅里叶变换系统参数的关系。

The accelerated algorithm of volume rendering based on textures mapping and the wavelet-based multiresolution volume rendering in network are performed by using OpenGL 3D visualization technique. From the point of view of computer graphics, 3D visualization mechanism of volume rendering based on OpenGL textures mapping is studied, including modelview transformation, projection transformation, perspective division, viewport transformation and the ways to embed textures mapping and blending in above four transformations.

利用OpenGL三维可视化技术实现了本文所提出的基于纹理映射的体绘制加速算法和网络环境下基于小波的体数据的多分辨率体绘制，并从计算机图形学的角度，研究了基于OpenGL纹理映射技术的体绘制的三维可视化流程，包括OpenGL的模视变换、投影变换、透视除法、视区变换，以及纹理的定义、映射与融合等步骤在上述四个变换中的嵌入方法。

The paper mainly discusses the distinguishing usage of the isoparamentric transformation idea to deal with complicated physiological structure, such method as fibrous finite element division, material parameter transformation concerned non-homogeneity, numerical integral with multi-layered composite, and inverse mapping considered complex boundary condition and loads.

本文主要介绍了等参变换思想、方法在建模分析中的特色应用，如基于纤维结构的等参有限单元离散、考虑非均匀性的材料参数等参变换、层和数值积分和考虑复杂边界条件及负载特性的逆变换等均是运用等参变换的思路来处理复杂的生理结构问题。

Stability analysis: A stability analysis method for equilibrium point of closed systems is proposed.

本文所提出的闭环系统分析方法在电流模控制变换器及准谐振变换器中的推广应用表明了本方法具有宽广的应用前景，因为它们是传统PWM变换技术在控制方法及主电路变换技术方面的新发展。

At present, most of the image watermarking algorithms based on the wavelet transform fail to take into account the shortcoming that the first generation wavelet transform used in image processing will introduce quantization errors inevitably, because of the storing characteristics of the image. Wavelet transform that maps integers to integers will not introduce quantization errors. Its time-frequency analysis method and multi-scale property accordant with human being vision system makes integer wavelet transform an ideal way for digital watermarking.

目前，大多数基于小波变换的图像水印算法没有考虑到第一代小波变换用于图像处理中不可避免的引入量化误差的缺点，而整数小波变换除了具有小波的多分辨率分析与人类视觉特性一致、具有良好的时频特性等优点以外，还避免了第一代小波变换用于图像处理中引入量化误差等缺点。

A set of complex Morlet wavelet are applied on projection slice of each direction to decompose each projection into several frequency channels,the average and variance extracted are computed in each frequency channel,and then linear regression model is employed to computer realationship feature between frequency channels.1-D DFT is applied to features and the amplitudes of Fourier coefficient are selected as features,then the extracted features are rotation invariant.

该算法是将一定大小的图像进行二维傅里叶变换；其次在变换后的图像中央选择一个圆盘区域，并在方向［0°，180°］内进行等间隔角度频率抽样，实现方向分解，使用一组复Morlet小波对每个方向上的映射切片进行小波变换，从而实现多通道频率分解；在各个频率通道中计算均值和方差作为特征，并利用线性回归模型计算频率通道之间的关系特征；将特征沿方向进行一维傅里叶变换并取其幅值，从而得到旋转不变性特征。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。