A color based face detection system using multiple templates

A color based system using multiple templates was developed and implemented for detecting human faces in color images. The algorithm consists of three image processing steps. The first step is human skin color statistics. Then it separates skin regions from non-skin regions. After that, it locates the frontal human face(s) within the skin regions. In the first step, 250 skin samples from persons of different ethnicities are used to determine the color distribution of human skin in chromatic color space in order to get a chroma chart showing likelihoods of skin colors. This chroma chart is used to generate, from the original color image, a gray scale image whose gray value at a pixel shows its likelihood of representing the skin. The algorithm uses an adaptive thresholding process to achieve the optimal threshold value for dividing the gray scale image into separate skin regions from non skin regions. Finally, multiple face templates matching is used to determine if a given skin region represents a frontal human face or not. Test of the system with more than 400 color images showed that the resulting detection rate was 83%, which is better than most color-based face detection systems. The average speed for face detection is 0.8 second/image (400 x 300 pixels) on a Pentium 3 (800MHz) PC.     

基于内模原理的状态反馈控制在陀螺平台视轴稳定系统中的应用

针对陀螺平台视轴稳定系统快速隔离扰动、稳定视轴的要求,设计了以挠性速率陀螺为核心的两轴陀螺稳定平台。结合某光电侦查导引系统设计过程,在多环路从属控制结构中引入内模控制,使位置环、速度环、电流环顺序依次投入运行,以快速的内环路有效抑制干扰,而主环路仍以窄带宽保证跟踪精度,达到了良好的控制效果,满足了高精度光电侦查导引系统对陀螺稳定平台快速性和稳定性的要求。     

Development of a middle and low latitude theoretical ionospheric model and an observation system data assimilation experiment

On the basis of previous work, we develop a middle and low latitude theoretical ionospheric model in this paper, named Theoretical Ionospheric Model of the Earth in the Institute of Geology and Geophysics, Chinese Academy of Sciences （TIME-IGGCAS）. TIME-IGGCAS solves the equations of mass continuity, motion and energy of electron and ions self-consistently and uses an eccentric dipole field approximation to the Earth＇s magnetic field. We combine the Eulerian and Lagrangian approaches in the model and take account of the plasma ExB drift velocity. Calculation results reveal that the model is steady and credible and can reproduce most large-scale features of ionosphere. By using TIME-IGGCAS, we carried out an observation system data assimilation experiment. Assimilation results show that the ExB drift velocity can be accurately estimated by ingesting the observed foF2 and hmF2 into the model applying nonlinear least-square fit method. We suggest that this work is of great significance in the development of ionospheric data assimilation model to give better nowcast and forecast of ionosphere.     

高层建筑刚性桩复合地基承载受力性状研究

为研究高层建筑刚性桩复合地基的工作机理和荷载传递特性,在南京某高层建筑刚性桩复合地基工程现场进行了多项复合地基原位载荷试验与应力测试.根据试验数据,对复合地基承载机理、应力分布和变化规律进行了分析与探讨.对四桩复合载荷试验进行了数值模拟,分析结果与实测数据吻合较好.研究结果表明:桩体对桩间土的加固效果随荷载水平增加而提高,桩间土承载力提高系数为1.16,发挥系数为0.88~1.00;桩土应力比随荷载增加而增大,最终稳定于15~17之间;加载过程中,刚性桩的承载力发挥滞后于桩间土,桩侧阻力的发挥早于桩端.基于试验和数值模拟的结果,提出承载力取值标准的建议,可供同类工程设计和研究参考.     

构建网络经济时代的ECR营销渠道模式

为适应网络经济时代全球化竞争的需要,我国企业必须重视研究消费者需求及其行为的变化,在改革传统营销渠道模式的基础上,应建立新的需求导向（拉动）型的ECR营销渠道模式。     

基于Morlet组合小波的梳状滤波与包络检波方法

提出一种基于Morlet组合小波的梳状滤波和包络检波方法。梳状滤波在间隔的几个故障调制频率下进行窄带滤波,抑制噪声的能力强;Morlet组合小波构造简单,计算量小,仅改变组合小波的部分参数就可获得良好的滤波效果,方便灵活、适应能力强;Morlet组合小波的实部和虚部分别相当于一个零相移滤波器和一个90°相移滤波器,信号经小波变换后直接满足包络检波条件。工程应用结果表明:该方法对机械振动信号的滤波和包络检波一步到位,与故障特征频率相对应的包络谱谱峰清晰可见,适用于旋转式或往复式运动机械系统的故障诊断。     

压电智能梁振动主动控制分析的新方法

以智能梁为例研究智能结构分析的新理论新方法.以样条有限点法为例,从位移模式出发,以智能本构关系、瞬时变分原理以及样条离散化为基础建立了压电智能梁振动主动控制分析的控制方程,分析了两个典型算例.     

磁层顶电子剪切流K-H不稳定性

磁层顶是由经过舷激波的太阳风和地磁层相互作用而形成的边界层,其上有电流流动.本文将这种电流看成电子剪切流,来讨论夜侧磁层顶的电子剪切流所引起的Kelvin-Helmholtz(K-H)不稳定性问题.电子剪切流受到的洛仑兹力中包括了电场的作用,正是这种作用使得剪切不稳定性要复杂一些.本文对电子剪切流激发的K-H不稳定性进行了细致的分析,从而得知,电子流剪切引起的K-H不稳定性倾向于在磁层顶内侧激发,并且只有当剪切速率在上下两阈值之间时,才可能激发K-H不稳定性.本文对比了夜侧近地磁层顶和磁尾磁层顶,发现当磁层顶两侧电子数密度之比恒定时,高电子数密度的磁层顶侧易产生K-H不稳定性.而磁鞘侧电子数密度n2与磁层侧电子数密度n1之比n2/n1的改变对不稳定性的影响也很显著:较大的n2/n1产生的K-H波主要是在低速区域,其有效增长率较小.     

铀尾矿浸出液对蚕豆(Vicia faba)早期生长的影响

利用室内培养法研究了铀尾矿浸出液对蚕豆(Vicia faba)根尖细胞的微核率、核酸酶活性及对蚕豆种子萌发的影响.结果表明:铀尾矿浸出液达到一定剂量时均可引起蚕豆根尖细胞微核数增加,微核数随浓度增大而逐渐增多,说明铀尾矿对蚕豆幼苗具有明显的遗传毒性效应;铀尾矿对蚕豆种子的萌发率没有影响;铀尾矿促进幼苗的生长,低浓度比高浓度明显;低浓度铀尾矿浸出液对核酸酶有一定的激活作用,高浓度则抑制.当铀尾矿浸出液浓度逐渐增大时,抑制作用逐渐增强.图1,表4,参14.     

钻井泥浆泵泵冲流量测量系统的研制

钻井泥浆泵泵冲流量测量系统是石油钻(修)井行业中一种重要的泥浆泵冲和入口测量的测量仪表.文章介绍了泵冲流量测量系统的原理,阐述了该仪表系统的设计原理及关键技术.该系统能为钻(修)井泥浆注入量提供准确显示.便于司钻和钻(修)井监督们第一时间了解泥浆泵的工作情况和掌握井筒内泥浆的压力状态.实验证明,该系统测量精度.可靠性均很理想,值得推广应用.