基于Curvelet变换阈值法的地震数据插值和去噪

成功的信号分离和去噪依赖于所用的变换能否足够稀疏地表达该类信号.事实上,信号在某变换域的系数越稀疏,阈值去噪的效果也就越好.Curvelet变换是一种非自适应的多尺度.多方向性变换,地震数据在Curvelet域有着几乎最优的稀疏表达.最近的研究表明,Curvelet阈值能够得到比小波阈值更好的随机噪声抑制效果,更高的提...     

基于自适应正交变换线性组合器的EP信号压缩方法

研究了自适应正交变换线性组合器（ＡＯＴＬＣ）的原理，并将其应用于ＥＰ信号的数据压缩之中，分析和计算机模拟的结果表明，在保持同样压缩率的情况下，对ＡＯＴＬＣ压缩数据所恢复的ＥＰ信号进行潜伏期变化估计的性能，优于采用常规的差分脉冲编码调掉（ＤＰＣＭ）方法压缩重建ＥＰ信号并估计潜期变化的性能在保持各自潜伏期估计性能相近的情况下，ＡＯＴＬＣ的压缩率优于ＤＰＣＭ，另一方面，ＡＯＴＬＣ具有削弱随机噪声的能力，     

基于分数阶傅里叶变换的声呐探测信号鉴别

针对水下声发射源较多,为能准确鉴别敌我声呐发射源问题.利用数字水印技术,结合分数阶傅里叶变换(FRFT)的良好时频特性,提出了基于分数阶傅里叶变换的声呐水印方法,通过在声呐信号的分数阶傅里叶变换域进行数字水印的嵌入,结合声呐信号在分数阶傅里叶变换的系数特性,选择合适的水印位置.利用嵌入前与嵌入后信号的特性自适应设定水印检测阈值,实现对声呐信号的鉴别.通过仿真分析验证了该方法的可行性,在仿真结果中示出该方法在保证具有较高的分辨力,以及较大的水印容量的同时,水印的鲁棒性较好,检测精度得到了进一步的提高.     

一种基于3/2维谱的水中目标调制信息提取方法

利用目标辐射噪声的调制信息可以实现对目标的高方位分辨。为了能够准确获取目标调制谱特征,提出了一种基于小波变换和多分辨率分析理论的辐射噪声调制信息提取方法。首先提取水下目标辐射噪声的调制包络信息,之后对动态调制包络进行3/2维谱分析,从而得到辐射噪声的谐波信息。最后对实测噪声数据进行了仿真研究,结果表明,该方法可以有效提取噪声中动态调制信息。     

Forecasting container throughput based on wavelet transforms within a decomposition-ensemble methodology: a case study of China

To improve predictive accuracy, new hybrid models are proposed for container throughput forecasting based on wavelet transforms and data characteristic analysis (DCA) within a decomposition-ensemble methodology. Because of the complexity and nonlinearity of the time series of container throughputs at ports, the methodology decomposes the original time series into several components, which are rather simpler sub-sequences. Consequently, difficult forecasting tasks are simplified into a number of relatively easier subtasks. In this way, the proposed hybrid models can improve the accuracy of forecasting significantly. In the methodology, four main steps are involved: data decomposition, component reconstruction based on the DCA, individual prediction for each reconstructed component, and ensemble prediction as the final output. An empirical analysis was conducted for illustration and verification purposes by using time series of container throughputs at three main ports in Bohai Rim, China. The results suggest that the proposed hybrid models are able to forecast better than do other benchmark models. Forecasting may facilitate effective real-time decision making for strategic management and policy drafting. Predictions of container throughput can help port managers make tactical and operational decisions, such as operations planning in ports, the scheduling of port equipment, and route optimization.     

做好站场改造中LKJ电务数据的准确提报

分析了站场改造工程新旧设备更替中,LKJ基础数据测量遇到的困难,并提出了准确提报的测量方法.     

柴油机燃油电控喷射用快速电磁阀设计的几个基本问题

本文从快速电磁阀的作用和功能转换分析出发。提出了设汁高效快速电磁阀的途径和应注意的问题。为了进一步提高其快速性,对多极电磁铁的结构与电磁参数进行了分析。指出为了减小线圈的时间常数,必须有高的功率输入和采用多个小线圈的结构。     

A high-performance low cost inverse integer transform architecture for AVS video standard

A high-performance, low cost inverse integer transform architecture for advanced video standard (AVS) video coding standard was presented. An 8×8 inverse integer transform is required in AVS video system which is compute-intensive. A hardware transform is inevitable to compute the transform for the real-time ap-plication. Compared with the 4×4 transform for H.264/AVC, the 8×8 integer transform is much more complex and the coefficient in the inverse transform matrix Ts is not inerratic as that in H.264/AVC. Dividing the Ts into matrix S8 and R8, the proposed architecture is implemented with the adders and the specific CSA-trees instead of multipliers, which are area and time consuming. The architecture obtains the data processing rate up to 8 pixels per-cycle at a low cost of area. Synthesized to TSMC 0.18 μm COMS process, the architecture attains the operating frequency of 300 MHz at cost of 34 252 gates with a 2-stage pipeline scheme. A reusable scheme is also introduced for the area optimization, which results in the operating frequency of 143 MHz at cost of only 19 758 gates.     

基于连续子波变换的铁路车轮踏面擦伤的在线检测

在分析国内外关于铁路机车车辆车轮擦伤在线检测的应用和方法的基础上,提出了利用连续子波变换对车轮钢轨的振动加速度信号进行分析,当车轮踏面出现擦伤时,其振动信号中的幅值出现突变点。通过对实测数据的分析并与信号的倒谱分析比较证明,这种方法较常规的方法更有效地应用于车轮踏面擦伤的诊断中。     

基于小波变换和Gabor滤波的指纹图像增强算法

在指纹自动识别系统中,图像增强是比较重要的一个环节,它直接影响到指纹识别系统的识别精度．利用指纹图像在经小波多尺度分解后,低频部分集中了指纹图像的主要纹理信息这一特性,提出了一种在小波域对指纹图像进行Gabor滤波增强的算法,实验表明,该算法能够使图像的质量明显得到增强,方便了后续指纹特征的提取。