数字调幅广播系统中包络检波方法的研究

介绍了数字调幅广播的检波方法,给出了两种实现检波的实际算法:FFT和DCT,重点论述了两种算法的原理以及在实现数字广播包络检波过程中的工作原理。最后利用MATLAB对这两种方法进行了性能仿真并比较了两种检波方法的误码率。     

基于N维Arnold与DCT变换的信息隐藏算法

文章提出了一种新颖的把隐藏信息嵌入预选图像,通过N维Arnold置乱预选图像实现信息加密,并对载体图像进行DCT变换嵌入置乱图像的信息隐藏算法.主要包括N维Arnold图像置乱、信息的嵌入与提取算法.利用matlab6.5平台进行了算法实验,实验的结果表明该算法具有较强的隐蔽性和鲁棒性,其隐藏信息量大,信息类型多,因此在internet通信领域中具有较高的使用价值.     

Optimization of recharge and pumping rates by means of an inverse 3D model

The paper concerns the optimization of pumping and artificial recharge rates under hydraulic head constraints. This optimization is accomplished by means of an inverse three-dimensional (3D) model which is a combination of a numerical model, sensitivity analyses and nonlinear regression. The optimization criterion used is the minimization of the sum of the squares between the calculated and the desired water table maps. These maps were established for the end of each month of the period from December to August so that the annual average flux is outward from the modeling area. This outward flux will push back the salt water intrusion. The assumed natural recharge rates of the different months equal the mean values of the period 1958–1977. The aquifer parameters describing the water conducting and storing properties are also required as input data as well as the initial hydraulic heads. The optimized parameters are the artificial recharge rates of the months December, January, February and March and the pumping rates of the months April, May, June, July and August. For the first-mentioned months, the pumping rates are considered as known. During the last-mentioned period, no artificial recharge is possible. A unique solution is obtained. To check the optimized rates, a water balance is made. With this balance, it is shown that the treated phreatic aquifer can be used as a subterranean reservoir to store water that is abundantly present in the winter until the summer when water demand is large. It is also proved that the salt-water intrusion can be stopped by the temporal storage of the artificial recharged water.     

高拱坝泄洪振动水弹性模型

以小湾工程为背景，通过水弹性模型实验，判断高拱坝泄洪所引起的振动和影响，采用自己研制的物理和力学性能优良的加重橡胶材料，在计算机的辅助下，建成了１：１５０比尺的水弹性实物模型，完善了对库水－地基－坝体－脉动荷载相互作用的模拟；采用先进的测试手段和分析软件包，对该模型的模态和多种工况泄水响应进行了全面的测试与分析，并采用计算机数值模拟与实验成果相结合的方法对坝身泄洪振动进行了结构动力分析及反分析和反     

AN INVERSE PROBLEM OF WATER WAVE GENERATION IN A WAVE TANK

ＡＮＩＮＶＥＲＳＥＰＲＯＢＬＥＭＯＦＷＡＴＥＲＷＡＶＥＧＥＮＥＲＡＴＩＯＮＩＮＡＷＡＶＥＴＡＮＫＭｉａｏＧｕｏ－ｐｉｎｇ；ＹｏｕＹｕｎ－ｘｉａｎｇ；ＬｉｕＹｉｎｇ－ｚｈｏｎｇ（ＳｈａｎｇｈａｉＪａｏＴｏｎｇＵｎｉｖｅｒｓｉｔｙＳｈａｎｇｈａｉ２０００...     

一个流水线型三维DCT硬件核的设计

在优化3D-DCT算法的基础上,采用流水线型结构,系数转换、矩阵转置、数据装载和截位的通盘解决方式,构造一个流水线型的三维DCT硬件核,使运动图像的压解中DCT运算的CPU耗时下降十几倍,实现实时压缩。     

基于H.263的实时视频编码技术研究

为了提高H．263编码技术现有算法的执行效率，本文提出了一种基于时域预测的预判零方法，该方法在保证一定图像质量的条件下具有较高的判别效率，能节约大量的编码时间：并在此基础上结合“钻石”运动搜索算法、MMX优化技术，实现了利用软件进行实时视频编码。     

一种自适应的帧/场DCT变换在MPEG-2中的应用

结合MPEG-2标准语法详细分析了一种自适应选择帧/场DCT变换的算法，产生了一个符合MPEG-2语义的视频流。     

JPEG算法的研究及其在医学图像中的应用

图像压缩编码的目的就是要用尽量少的比特数表示图像,同时保持复原图像的质量,使它符合特定应用场合的要求。在介绍经典压缩算法中有代表性的编码算法的同时,重点介绍了JPEG基本算法;研究了JPEG算法的基本原理,分模块分析研究了DCT变换、量化、熵编码和游程编码的原理和功能,并且采用MATLAB程序设计语言对JPEG算法进行仿真实现,得到了较好质量的压缩图像。     

基于分布式压缩感知的全极化雷达超分辨成像

基于分布式压缩感知理论,提出了一种全极化逆合成孔径雷达超分辨成像算法,联合各极化通道进行超分辨处理.首先,建立全极化信号模型及超分辨字典,利用各极化通道信号的联合稀疏性将全极化超分辨成像建模为最小L2,1范数的优化问题,运用一种快速算法求解该优化问题.由于利用联合稀疏约束,多极化通道联合成像相比于单通道成像能够获得更好的超分辨性能和噪声抑制能力,最终有效提高图像极化融合的效果.同时,采用快速傅里叶变换操作提升了算法的运算效率.基于backhoe的仿真数据实验验证了该算法的优越性.