基于视频的车流量检测建模与分析

交通流量信息是智能交通控制中的关键成分。论文在对视频图像进行灰度处理、频域滤波和均衡化的基础上,结合直方图分析、背景差分、动态阈值二值化处理等图像分析过程,提出了双虚拟线平均法检测多车道车流量,并完成参数灵敏度检验。针对初识背景提取时间过长的问题,加入了跳帧法和像素块法,以提高系统效率。考虑到背景的时变性,采用选择更新法进行周期更新。实际结果表明,该方法兼顾了智能交通系统的环境适应性、检测实时性和统计精确性等要求,四个车道车流量统计的准确率均大于90％。     

基于ViBe算法的改进背景减去法

ViBe背景减去算法基于RGB色彩空间对像素进行处理,在光照突然改变的情况下,会造成大面积的背景误判为运动前景;同时会将场景中的运动背景大量的误检为前景. 针对上述问题,本文提出一种结合（r,g,I）标准色彩空间的改进算法. 实验结果表明,改进算法在光照突然变化时对前景的提取具有更好的鲁棒性,同时对于场景中运动的背景像素点,取得了更好的检测效果.     

分布式光纤测温系统在煤矿火灾检测中的应用

摘要：针对煤矿安全存在潜在的火灾问题,文中主要介绍分布式光纤测温原理及其在煤矿火灾监测中的应用。在系统结构上,本文提出了一种优化设计方案。此外,在信号处理方面,本文提出了一种命名为RLN-ELAM的新颖算法,用于检测并消除瑞利噪声对系统测量精度的影响,提高拉曼分布式光纤系统的测量精度。实验结果表明,利用此设计方案和算法后,可以使系统的温度分辨率、空间分辨率均有所提高,测量误差从7%降低到不足2%。在实验室进行的模拟实验中,对温度进行实际测量,结果表明,该煤矿火灾监测系统能够提供详细的温度分布情况并能够及时准确地报警,使工作人员随时掌握煤矿温度分布情况,及时准确地找到火灾发生区。     

钽平台-石墨炉原子吸收法测定高背景废水样品中的Cd、Pb

运用钽平台石墨管测定基体成分复杂的废水样品中的Cd、Pb元素,基本消除了基体残留影响和记忆效应,降低了背景吸收,提高了灵敏度。样品经超声波仪粉碎后直接进样,用校正曲线法测定,简化了操作步骤,减少了测定时间,延长了石墨管使用寿命。其测定值与石墨平台标准加入法测定值结果一致。样品回收率:Cd为96.9%～104%,Pb为98.2%～106%,Cd的相对标准偏差(RSD)为3.04%～4.24%,Pb的RSD为2.93%～6.53%。     

一种基于PCA的MPSK信号码元速率估计方法

针对MPSK信号的码元速率估计问题, 研究了有限数据条件下循环谱的谱线特征受到背景色噪声干扰的现象, 提出了一种基于主分量分析(PCA)的循环谱特征码元速率估计方法。PCA变换抑制了信号循环谱中的背景色噪声, 提高了估计精度, 减小了估计方差。仿真表明, 该方法在有限数据条件下具有良好的估计性能, 适用于不同成形滤波系数的MPSK信号。     

A minimum variance distortionless response filter based on the bifrequency spectrum for single-channel noise reduction

This paper deals with the problem of single-channel noise reduction in the short-time Fourier transform (STFT) domain. Many algorithms have been developed to solve this important problem, most of which generally assume that the STFT coefficients in different frequency bands are uncorrelated, so the noise reduction is achieved by applying a gain function to the STFT of the noisy speech in each frequency band. However, this assumption is not accurate and the STFT coefficients of speech signals between neighboring frequency bands are correlated in practice due to the use of small lengths of the fast Fourier transform (FFT) and overlap add/save techniques in implementation. This paper formulates the noise reduction problem by taking into account the interband correlation using the so-called bifrequency spectrum. Based on this formulation, a single-channel minimum variance distortionless response (MVDR) filter is derived, which is shown to be able to significantly improve the signal-to-noise ratio (SNR) and meanwhile maintain the desired speech not much distorted. Simulations are presented to justify the claimed merits of the developed MVDR filter.     

H ∞ control for discrete‐time nonlinear Markov jump systems with multiplicative noise and sector constraint

This paper addresses the finite horizon H _∞ control problem for a class of discrete‐time nonlinear Markov jump systems with multiplicative noise and nonlinear feedback device. The system nonlinearity occurs in a random way specified by a Bernoulli process, whereas the actuator and sensor nonlinearities are restricted to a sector region. Both the state and the dynamic output feedback H _∞ controllers are devised in terms of difference LMIs. The proposed approach not only allows the resulting system to achieve a prescribed disturbance attenuation level, but also enables the output of actuator/sensor to meet the designated sector condition. Moreover, it is also shown that our approach is well‐adapted for dealing with the discrete‐time Markov jump systems with saturated actuator and sensor. Finally, a backward iterative algorithm is provided to solve the obtained difference LMIs and a numerical example is presented to verify the efficiency of the theoretical results. Copyright © 2013 John Wiley & Sons, Ltd.     

机床噪声及降低噪声的途径

分析了机床噪声的起因，并提出了相应的降噪措施。     

不定积分中的几何背景和表格分部积分法

论述了数学背景对数学发展的重要性,提供了不定积分中的几何背景,介绍了不定积分的表格分部积分法及案例,对改革教学内容和改进教学方法进行了尝试。     

哈尔滨市主要道路交通噪声污染评价

针对哈尔滨市的主要道路交通噪声进行监测,统计并分析整体污染情况、噪声分级状况及空间分布特征。为哈尔滨市今后的道路交通噪声治理工作提供有利的依据,具有较好的实际应用价值。