查询词典 laplace transform

A method of the optical image encryption based on the frequency splitting domain and Fresnel domain is proposed, after the analysis of the fractional Fourier transform and Fresnel transform, by synthesizing the advantages of multi keys and lensless feature of the fractional Fourier transform and Fresnel transform in the optical image encryption system.

结合分数傅里叶变换及菲涅耳变换，在光学图像加密系统中分别具有多密钥性和无透镜性的优点，提出了基于分频域和菲涅耳域的光学图像加密方法。

Many new detection techniques are proposed, that include: To overcome the faults of cross-terms and short unambiguity range for the common Wigner-Ville Distribution , short-time Fourier transform and Gabor transform are applied to SAR moving target detection. To improve the detection performance of WVD in noise environment, a new technique based on the Cross-WVD is proposed. The application of fractional Fourier transform to chirp signal detection is analyzed and extended to SAR moving target detection. To eliminate the restriction of chirp-Fourier transform, a new modified definition is proposed and applied to SAR moving target detection. To detect multiple moving targets whose scattering intensities are different heavily, the CLEAN technique is combined with the above techniques and the ideal detection performance is achieved. At last, the whole dissertation is concluded.

具体的研究成果如下：针对常用的Wigner-Ville分布在多目标情况下存在交叉项，并且多普勒不模糊范围小的缺点，提出将短时Fourier变换和Gabor变换应用于SAR运动目标检测，分析了其优势所在；为进一步提高Wigner-Ville分布低信噪比条件下的信号检测能力，提出基于互Wigner-Ville分布的运动目标检测方法；分析了分数阶Fourier变换在线性调频信号检测中的应用，提出基于分数阶Fourier变换的运动目标检测算法；对离散Chirp-Fourier变换的定义进行了修正，提出修正的离散Chirp-Fourier变换，克服了限制其应用的约束条件，并用于SAR运动目标检测当中；强度相差较大的多运动目标检测历来是机载SAR技术的一个重点和难点，我们将CLEAN思想融入上述多种算法当中，良好地解决了该问题。

We can see from the existent technology of the natural gas transform, the routs of methane transform include two kinds: direct transform and indirect transform.

因此，我国对天然气的转化催化技术进行研究具有重大的战略意义。

To increase the security of the watermark, a new binary image encryption algorithm based on TD-ERCS map is presented. The watermark is encrypted by a chaos sequence generated by TD-ERCS map; A novel color image watermarking algorithm is proposed based on discrete chaotic map and 2-dimensions discrete wavelet transform. The watermark is encrypted by the new binary image encryption algorithm, and the encrypted watermark is embed into four sub-bands of the most deep level of blue branch of host image by three-level wavelet transform, and the embedded positions are determined by general cat cha otic map; A novel color-image blind detection watermarking algorithm is proposed based on integer wavelet transform and subsampling. The scrambled watermark is encrypted and embed into the low sub-bands after four sub-images of the Y branch of host image is transformed by two-level wavelet transform, and the embedded positions are determined by Logistic chaotic map, this watermarking scheme can realize blind extraction.

为了提高水印图像的安全性，提出了一种基于TD-ERCS混沌映射的二值水印图像的加密算法，该算法利用TD-ERCS映射产生的混沌序列加密水印图像；将离散混沌映射和二维离散小波变换相结合，研究了彩色图像水印新算法，该算法先对混沌序列加密后的水印图像进行小波变换，再嵌入到宿主图像的蓝色分量的最深层的四个子带中，嵌入位置则由广义猫映射确定；将整数小波变换和图像子采样技术应用于数字水印，提出了一种彩色图像盲提取水印算法，水印嵌入时，先对宿主图像在YIQ色彩空间中的Y分量进行子采样，并对得到的四个子图像分别进行二级离散小波变换，然后将置乱并加密后的水印图像嵌入到小波变换后的低频子带中，其嵌入位置由Logistic混沌映射产生的混沌序列确定，实现了水印的盲提取。

By using the spatial finite sine and cosine transform, and the temporal Laplace transform, the existence of the analytic solutions of its initial-boundary problems in a boundedspace domain with Dirichlet and Neumann boundary conditions is derived.

利用空间有限的sine或cosine变换及时间Laplace变换，给出了该方程有限区间上带Dirichlet和Neumann边界条件的两类初边值问题的解析解。

The exact solutions are then obtained for the equations characterizing flows of such fluids under an arbitrary pressure gradient by the method of integral transforms (Fourier Cosine transform and Laplace transform).

运用积分变换方法(Fourier余弦变换和Laplace变换)，求得了在任意压力梯度下流体运动方程的精确解。

This is achieved using Matlab on Laplace transform and inverse transform of the few examples.

这是用Matlab实现的关于Laplace变换及反变换的几个实例。

In the numerical calculation of electromagnetic transient response, the G-S transform method is used frequently for inverse Laplace transform.

在电磁场瞬变响应的数值计算中，常采用G-S变换法作逆拉氏变换。

The harmonic field of electric dipole source on the uniform earth surface is converted into transient field by inverse Laplace transform,and the Bz/ t transient curve is calculated.The Hz transient curves on the stratified earth surface are obtained from cosine transform calculated by broken line approximation.

由逆拉普拉斯变换将均匀大地面上的电偶极子源谐变电磁场转换为瞬变电磁场，并计算出Bzt瞬态曲线；对分层大地面上的瞬变电磁场，采用折线逼近法计算余弦变换得出Hz瞬态曲线。

Experimental results show that the proposed method outperforms the Laplace transform and wavelet transform methods.

实验结果表明该算法比拉普拉斯变换法和小波变换法具有更好的融合效果。

He's a pretty westernised kind of guy.

他是一个非常西化的人。

National spirit is the moral kingpin for a nation to realize common ideal and goal.

一、中华民族精神的基本内涵党的十六大报告指出：在五千多年的发展中，中华民族形成了以爱国主义为核心的团结统一、爱好和平、勤劳勇敢、自强不息的伟大民族精神。