中巴资源卫星-02星CCD图像条纹噪声消除方法研究

从遥感影像条纹噪声的周期性特征入手,利用图像的频谱图对图像中条纹噪声的频率分布进行分析,并使用巴特沃斯带阻滤波器对条纹噪声进行消除.实验结果表明,该方法能有效抑制条纹噪声,并能保留图像边缘信息.通过对条纹噪声分析发现中巴资源卫星-02星CCD图像存在4种条纹类型.     

环境噪声的无线传感器网络定位方法

提出了一种基于传感器节点周围环境噪音的定位算法和一个概率生成模型,并说明了传感器节点定位问题同模型中的最大似然估计是等价的。对于仿真传感器节点和Crossbow MICAZ传感器节点都给出了实验结果。     

液压系统噪声的分析与控制方法

噪声是液压系统常见的故障之一,分析处理这一故障有利于维护系统正常运行.文章对液压系统气穴及气泡产生噪声的原因进行了分析,并根据不同噪声产生的机理提出了行之有效的控制措施.     

Simulation of dual transponder carrier ranging measurements

The most dominant error source for microwave ranging is the frequency instability of the oscillator that generates the carrier phase signal. The oscillator noise is very difficult to filter due to its extremely low frequency. A dual transponder carrier ranging method can effectively minimize the oscillator noise by combing the reference phase and the to-and-fro measurement phase from the same single oscillator. This method does not require an accurate time tagging system, since it extracts phases on the same satellite. This paper analyzes the dual transponder carrier ranging system by simulation of the phase measurements with comprehensive error models. Both frequency domain and time domain noise transfer characteristics were simulated to compare them with dual one-way ranging. The simulation results in the two domains conformed to each other and demonstrated that a high level of accuracy can also be achieved by use of the dual transponder carder ranging system, with relatively simple instruments.     

电动滚筒驱动电机噪声的控制分析

电动滚筒是近年来出现的新型带式输送设备的驱动部件,具有适宜在恶劣场合工作的能力。然而,电动滚筒的噪声却带来污染,并在高要求场合应用受到限制,为此必须降低其噪声。在对电动滚筒可能存在的主要噪声源进行分析的基础上,应用频谱识别技术,确定了单相驱动电机是该型电动滚筒的主要噪声源,它使得电动滚筒在100Hz及其高次谐频噪声成分较大。经分析,造成此现象的原因是单相驱动电机的空间不对称驱动力矩,在采用三相电机驱动后,电动滚筒的噪声下降了6～7dB(A)左右,有效地控制了电动滚筒的电磁噪声。     

Navier-Stokes方程可加白噪音的随机小挠动

研究了二维区域上Navier-Stokes方程在较小∈可加白噪音;情形下的挠动,并得到当∈→0时,其随机吸引子是上半连续的.     

Kinematics,coordination, variability,and biological noise in the prone flutter kick at different levels of a “learn-to-swim” programme

Abstract

The purpose of this study was to establish the characteristics of the movement patterns common to flutter kicking of skilled swimmers and to determine how the movement patterns of swimmers at different levels of a “learn-to-swim” programme differ from those of skilled swimmers. Also, the nature of the skill afforded the opportunity to investigate learning of a cyclical multi-joint task from a motor control perspective. The underwater motion of nine children representing three levels of a “learn-to-swim” programme and 10 skilled swimmers were video-recorded while performing nine cycles of prone flutter kicking. Kinematics including joint angular motion and coordination of joint actions were calculated. Fourier analysis was applied to determine the frequency composition of the vertical undulations of the hip, knee, and ankle and to calculate the velocity of the body wave travelling caudally from hip to ankle. Fourier analysis also enabled investigation of biological noise, as distinct from variability. The results indicated the desired joint angles and coordination towards which learners could be guided. An index based on the ratio of hip – knee and knee – ankle body wave velocities showed that the inter-joint coordination of most learners was not appropriate for effective flutter kicking. There was strong evidence to suggest that skilled performance in flutter kicking is characterized by sequencing of joint actions to produce a single sinusoidal body wave moving caudally with not decreasing and preferably increasing velocity, low biological noise, and small variability.     

环境责任与企业债务融资行为实证研究

本文基于节能减排的环境责任,以1998-2010年重污染行业A股上市公司为样本检验了企业和银行节能减排的环境责任对企业的银行长期借款融资的影响。研究发现：固定资产与营运资本是重污染行业企业获得长期借款的重要指标,节能减排的环境责任与企业获得的银行长期借款显著相关,说明＂绿色信贷＂政策对重污染企业节能减排责任行为产生了积极的作用,也引起了企业财务杠杆选择的策略行为。     

基于横噪声消除的医学粘连图像边缘分割算法

针对CCD型医学图像中,在细胞粘连区域信号附近出现的较强的横条纹噪声干扰,影响图像信息的正确性,分割后会存在边界模糊和锯齿条文的问题,为提高医学图像分割效果,提出了一种基于横条纹噪声消除的医学粘连图像边缘分割算法。分析了医学图像中边沿横条纹噪声的原因,通过wold纹理模型与多尺度马尔可夫随机场模型,利用确定性随机场和不确定性随机场的谱属性不同的特征,将医学图像边沿的干扰特征分离开,有利于对粘连医学图像进行分割。实验证明,方法有效地去除了横条纹噪声并很好地保留了图像的边缘和细节信息,同时运算复杂度低。     

基于谱减法的语音增强算法研究

在通信质量日益提升的现代通信时代,对语音信号的处理研究仍然是一个基本而复杂的课题。在语音增强技术中产生了众多处理方法。笔者在谱减法的理论研究基础上,验证了谱减法对语音信号的语音增强在技术上有明显的效果。但是在谱减法中的＂音乐噪声＂处理上还是不如人意,仍然会出现节奏性的噪声,这也是日后不断需要研究的方向,以实现语音增强技术的理想化。