A Low-Latency Multi-layer Prefix Grouping Technique for Parallel Huffman Decoding of Multimedia Standards

Huffman coding is a popular and important lossless compression scheme for various multimedia applications. This paper presents a low-latency parallel Huffman decoding technique with efficient memory usage for multimedia standards. First, the multi-layer prefix grouping technique is proposed for sub-group partition. It exploits the prefix characteristic in Huffman codewords to solve the problem of table size explosion. Second, a two-level table lookup approach is introduced which can promptly branch to the correct sub-group by level-1 table lookup and decode the symbols by level-2 table lookup. Third, two optimization approaches are developed; one is to reduce the branch cycles and the other is parallel processing between two-level table lookup and direct table lookup approaches to fully utilize the advantage of VLIW parallel processing. An AAC Huffman decoding example is realized on the Parallel Architecture Core DSP (PAC DSP) processor. The simulation results show that the proposed method can further improve about 89% of decoding cycles and 33% of table size comparing to the linear search method.

基于小波的信号Lipschitz指数分析和应用

奇异信号往往带有一些重要信息,一般用Lipschitz指数来描述信号的奇异性。在Mallat等人的基础上讨论了奇异信号Lipschitz指数定义和相关理论基础,同时研究了小波变换与信号奇异性关系和Lipschitz指数的计算。利用信号和噪声奇异指数不同的特点应用于去噪声,文中提出了一种对噪声模极大值对应点周围的小波系数进行非线性压缩后重构信号新方法,仿真实验结果表明,这种方法有着较好的去噪效果。     

Degradation of starch by incubation with rumen fluid. A comparison of different starch sources

The degradability of starch from various feedstuffs was investigated in vitro by incubation of 500-mg amounts in 50 ml of a 3:1 rumen fluid/buffer solution at 39°C for 6 h. The rumen fluid was obtained from one of three cows fed on hay or hay and concentrate. The degree of degradation after 6 h incubation varied strongly for the 23 feedstuffs investigated. The degradation of starch from the same feedstuff in rumen fluid from a hay-fed cow was significantly lower than in rumen fluid from a concentrate-fed cow. It seemed that differences in degradability between feedstuffs were not determined by the ration of the donor cow, but merely by the properties of the starch. Processed feedstuffs showed a higher degradation of their starch than the unprocessed feedstuffs, independent of the ration of the donor cow. Particle size influenced degradation, but not of the starch of tapioca meal. A fairly constant ranking in degradability between the various feedstuffs was found. Fermentation of mixtures of feedstuffs showed about the same rate of degradation as found for the single products. Only when great differences in the degree of degradability existed was the degradation of the total starch enhanced. The time of collection of rumen fluid strongly influenced the in-vitro degradation of starch.     

A laboratory evaluation of a novel hot water cabinet for the decontamination of sides of beef

A hot water cabinet based on an idealized distributor design for the decontamination of sides of beef is described and a laboratory evaluation of this novel cabinet is reported.
Beef sides were inoculated with E. coli and exposed to mean water temperatures at the surface tissue ( T _f) of 83.5, 74.2, 66.0 and 44.5°C for 10 or 20 s. Mean log₁₀ reductions of bacteria for 10-s exposures were 2.23, 1.40, 0.91 and 0.2. For 20 s, reductions were 2.98, 2.14, 1.17 and 0.1. There was a significant ( P < 0.05) linear relationship between log reductions and T _f which varied with exposure time. At a T _f of 83.5°C with exposure times greater than 20 s, carcass bloom was judged to be permanently and adversely affected. At shorter times or with lower temperatures this did not occur.
Evaporative heat losses were well correlated with the pressure driving force ( r = 0.89) and gravity driving force ( r = 0.92) for air interchange between the cabinet and its surrounds.
The running cost using the distributor cabinet was one-third of that of an existing spray cabinet when compared at the maximum reduction of log 1.3 (95%) achieved by the spray cabinet. An additional advantage of the distributor cabinet is its constructional simplicity.     

语音信号处理技术

语音信号处理用以实现人一人、人一机器和机器一人的通信，是现代通信领域的重要环节。本文详细介绍了其三个分支，即语音编码、语音合成、语音识别和理解的研究和应用现状及其发展。     

车道线实时检测与偏离预警系统设计与研究

为保证交通安全,设计了一种基于单目视觉的车道偏离检测系统,利用 车载前视摄像 头获取图像,实时对动态图像进行处理,在驾驶员非主观偏离车道时进行报警。首先研 究了图像预处 理技术,包括灰度化、截取有效区域、滤波去噪、图像灰度增强、边缘检测和边缘修复功能 。其次对预处 理后的图像进行车道线检测,为有效识别具有车道线特征的图像,提出了一种改进的Hough 变换算法;对 没有车道线特征或车道线特征不明显的图像,采用了动态检测方法。在此基础上,提出 了一种车道线 纠正算法,即四点标定逆透视变换,将车道图像转化为俯视图,建立图像坐标系与实际俯视 坐标系之间的 关系,得到实际车辆的位置和偏移角度,判断该车辆的情况并作出指示。最后,在实际道路 中对设计中关 键技术以及整个系统进行了实验,大量实验结果表明,本文系统能在多种环境的道路中实现 车道线的准确识别和偏移判断,具有良好的实时性和鲁棒性。     

半导体器件纵向结构模拟工具

介绍了半导体器件纵向结构准三维模拟方法，包括版图信息提取，二维工艺模拟等功能。该模拟器可以根据版图信息和工艺参数自动显示器件上任意切线位置处断面图，稍加修改即可用于对Ｓｉ压力传感器等部分压电器件进行工艺模拟。     

倒锥微孔阵列的激光微加工技术研究进展

激光微加工技术凭借其加工效率高、加工材料广泛、无物理损伤以及操控性强等优点在高精度机械部件的加工上有较好的应用前景,易加工出尺寸微小、数量庞大、高品质的倒锥微孔阵列.首先对激光加工微孔的工作原理和特点进行了介绍,综述了激光在加工微孔阵列、倒锥微孔以及倒锥微孔阵列的研究现状,详细介绍了准分子激光、飞秒激光、纳秒激光在加工...     

基于Matlab的彩色图像分量处理

应用于图像处理的计算机软件技术平台很多,如VC++,Matlab等,Matlab从本质上就可以提供对图像处理的技术支持.在对彩色图像进行概述的基础上,提出彩色分量处理的方法,利用Matlab中的函数对其进行滤波处理,主要是进行平滑和锐化,经过仿真得出其方法效果明显,可改善图像的视觉效果的结论.     

一种基于独立成分分析的水下宽带信号波达方位估计方法

在水下目标特征信息缺乏、声纳阵列孔径有限的条件下,对水下宽带信号开展高分辨率、高精度的波达方位估计研究,具有明显的研究意义和应用价值。利用水下信源统计独立的特点,采用基于独立成分分析的状态一致性变换算法进行方位估计;考虑到水下加性噪声的高斯分布特性,利用小波降噪的预处理技术,消减混合信号中的高斯噪声成分;针对状态一致性变换在低频段的性能退化,提出一种空间重采样修正方法。使用上述基于空间重采样修正的状态一致性变换算法对仿真及海试数据进行处理,目标方位估计结果表明：该方法具有角度分辨率高、需要阵元数少、对先验知识依赖小、低频段性能稳定的优点,相比常规波束形成、子空间法、传统状态一致性变换3类方法更具性能优越性与实用性。