一种基于尾匹配q-gram的近似串匹配算法

近似串匹配是生物信息学、文本检索、信号处理等领域的一个基础问题,如何提高近似串匹配的速度一直都是研究的关键问题。提出一种新的在大文本库中快速查找近似匹配的无损过滤算法。为保证在大文本库中的匹配速度,本算法使用了查询速度较快的q-gram索引。为通过提高过滤算法的过滤效率达到提升算法整体性能的目的,详细分析了含有匹配串的文本区域,提取了一些基于尾匹配q-gram特征的新过滤条件,然后用这些特征优化了过滤算法的过滤标准。实验数据表明,新过滤条件有效地提高了算法的过滤效率,提升了算法的整体性能。结果显示新算法适合各种匹配错误率下的近似匹配,算法的通用性较强。     

基于超声波六元阵列测距的WSN节点定位技术研究

基于超声波测距的定位技术以其精度高、范围广和性能稳定等优点,在无线传感器网络中广泛应用。为了实现较大范围的高精度定位,利用自主实现的超声波六元传感器阵列进行TDOA测距,并进行测距误差分析,然后采用基于测地距离的多维定标算法(Geodesic Distance MDS)进行无线传感器网络节点定位。在MATLAB平台下与Cricket采用的迭代式三边定位和AHLoS采用的多点定位算法进行对比仿真实验,结果表明Geodesic Distance MDS算法在不同网络规模和测距误差条件下均能够获得更高的定位精度和较小的定位误差。     

Color recovery of black-and-white halftoned images via categorized color-embedding look-up tables

A new method of recovering the original colors of black-and-white (B&W) halftoned images with homogeneous dot patterns is proposed. The conventional inverse halftoning method, which uses a look-up table (LUT), can establish the relation between the halftoned patterns and the corresponding gray levels, while the conventional reversible color to gray conversion method can recover the original colors from a given color-embedded gray image. To accomplish our goal of original color recovery from B&W halftoned patterns, an approach of combining the conventional inverse halftoning and reversible color to gray conversion is presented in this paper. Differently from the conventional method of inverse halftoning via LUT, four LUTs categorized according to the red, green, blue, and gray reference colors are designed to more accurately map a specific B&W halftone pattern into the corresponding color-embedded gray level based on the observation that the shapes of the halftone patterns depend on input colors, thereby increasing the color recovery accuracy. Also, a color mapping method based on a linear regression which models the relation between the recovered colors and the original colors is introduced to adjust the initially recovered colors more closely to the original colors. Experimental results show that unknown original colors can be recovered from B&W halftoned images via the proposed method.     

气力流槽的设计计算

气力流槽是一种常用的固体粉料、粒料的输送设备。它适用范围广,结构简单,制造价格低廉。本文从理论上论述了影响气力输送物料流量的各个因素,为设计和使用设备提供了理论依据。     

Transport processes during electrowashing of filter cakes

Applications of electric fields during washing of filter cakes increases the removal rate of ions from the cake mother liquor, and under appropriate conditions the field also increases the wash flow rate by electroosmosis. Experimental data that show the key effects of the fields on the rates of ion mass transfer are presented: with the downstream electrode acting as a cathode, cation removal rates are increased whilst the removal rate of the anions is decreased. The concentration profile of the cations with washing time shows an increase in concentration to a value above that of the mother liquor, before it decreases due to displacement by the fresh wash liquor. A model is formulated that describes the advection, dispersion, ion migration and electroosmosis transport processes in the cake. Numerical solution of the model gives cation concentration profiles at the exit of the cake that are in qualitative agreement with the experimental observations. Experimentally measured wash liquor flow rates tend to be lower than what traditional colloid science principles predict by a factor of 5-10: reasons for this difference, supported by experimental work from other researchers, are discussed.     

一种实用直流放大器的设计

本文设计的直流放大器由直流放大模块和测试模块两部分组成。在直流放大模块中设计了稳压电源和混有200mV串模工频干扰的直流信号发生器;测试模块用来检测直流放大器的直流电压增益、输入阻抗、共模抑制比等参数。实验数据表明各性能参数都满足要求。     

基于HSV空间的彩色图像直方图检索技术

传统彩色图像的直方图检索技术基于RGB空间,但研究发现,RGB空间不符合人眼的视觉感应。因此本文提出的算法是在HSV空间上计算彩色图像的三维直方图,通过非均匀的划分三个分量色相H（Hue）、饱和度S（Saturation）和亮度V（Value）的采样区间,得到不同的检索结果。实验结果分析表明,在HSV空间,不同的分量在不同类型的图像中的作用是不一致的。     

基于颜色与投影特征的车牌定位

车牌定位是车牌识别系统的关键技术。定位的准确与否直接影响车牌识别的结果。本文根据车牌的颜色特征和投影特征提出了一种综合颜色特征和投影特征相结合的定位方法,算法分为粗定位和精确定位。该方法较单一特征的定位方法有较好的通用性,可适应于不同背景、不同光照下的汽车图像,能够确定出车牌区域,准确率得到了较大提高。     

Java 反射技术浅谈

反射是指程序可以访问、检测和修改它本身状态或行为的一种能力。通过反射,Java程序可以加载一个运行时才得知名称的class,得到其完整内部信息,并创建其对象,或对其属性进行设值,或调用其方法。反射是提高Java程序的灵活性和可扩展性至关重要的技术,它使得Java软件系统具有自适应能力。     

一种非线性动态系统参数估计方法

从非线性动态系统的参数估计问题出发,介绍了一种新的估计方法——粒子滤波估计法,该方法是一种基于贝叶斯推理和蒙特卡罗方法递推算法,通过动态模型推导了粒子的数值,通过实例分析了该估计方法的性能.结果表明,粒子滤波方法能显著提高估计性能,且精度高,比较灵活.