带参数的二次三角多项式样条曲线

给出了带有参数λ的二次三角多项式样条曲线。与三次B样条曲线类似,曲线的每一段由相继的4个控制顶点生成。对于等距节点,在一般情形下,曲线达到了C1连续,而当λ=1时,曲线达到了C3连续。λ有明确的几何意义,λ越大,曲线越逼近控制多边形。还给出了用此种曲线表示椭圆和整圆的方法,在相同的控制顶点下,可生成一簇椭圆弧和圆弧。     

基于三点分段的三角多项式样条曲线

给出了m(m=1,2,3)次三角多项式样条曲线。与二次B样条曲线类似,曲线的每一段由相继的3 个控制顶点生成;对于等距节点,一次三角多项式样条曲线是C1连续、二次三角多项式样条曲线是G2连续、三次三角多项式样条曲线是C3连续,且讨论了3 种曲线对控制多边形的逼近及与二次B样条曲线的对比。还给出了一次三角多项式样条曲线表示椭圆和整圆的方法。通过加权混合可得到一类三角多项式样条曲线,曲线的形状随着次数m和形状参数λ的变化而改变。     

平面场仿射变换的若干新结论

对平面场 的仿射变换问题作了进一步研究,给出9个定理,揭示了平面场仿射变换中一些量化关系,给出了例题。     

空间仿射变换中的定点等比平面族

对空间仿射变换作了进一步研究，提出并用解析法证明了空间仿射变换下，平面图形变换前后，其面积之比为定值的平面位置的分布规律，而且确定了这些平面的位置，建立了空间仿射变换中定点等比平面族的新概念。在此基础上得到了三轴椭球体的一个性质。最后，给出了实例，并在实例中，用精确的数学表达式，给出在预设三轴椭球体上截出预定断面面积的全部位置和这些平面的包络面方程。     

基于面部曲线弹性匹配的三维人脸识别方法

提出一种基于面部径向曲线弹性匹配的三维人脸识别方法。使用人脸曲面上的多条曲线表征人脸曲面,提取三维人脸上从鼻尖点发射的多条面部径向曲线,对其进行分层弹性匹配和点距对应匹配,根据人脸不同部位受表情影响程度不同,对不同曲线识别相似度赋予不同权重进行加权融合作为总相似度用于识别。测试结果表明该方法具有很好的识别性能,并且对表情、遮挡和噪声具有较好的鲁棒性。     

基于小波计算的平面物体射影不变性的识别

利用非均匀有理B样条从单幅图像中提取平面物体在射影变换下的几何不变特征,建立经典框架.讨论用小波计算框架的一维和二维特征不变矩的方法以减少计算量.实验结果表明所选取的特征不变量和算法有较小的计算量,对二维平面物体的识别有很好的性能,特别是允许景物中有部分的遮挡物存在.     

基于小波计算的平面物体射影不变性的识别

利用非均匀有理B样条从单幅图像中提取平面物体在射影变换下的几何不变特征,建立经典框架.讨论用小波计算框架的一维和二维特征不变矩的方法以减少计算量.实验结果表明所选取的特征不变量和算法有较小的计算量,对二维平面物体的识别有很好的性能,特别是允许景物中有部分的遮挡物存在.     

基于小波计算的平面物体射影不变性的识别

利用非均匀有理B样条从单幅图像中提取平面物体在射影变换下的几何不变特征,建立经典框架。讨沦用小波计算框架的一维和二维特征不变矩的方法以减少计算量。实验结果表明所选取的特征不变量和算法有较小的计算量,对二维平面物体的识别有很好的性能,特别是允许景物中有部分的遮挡物存在。     

平面中线上分布的大规模散乱数据点局部基自然样条插值

给出了平面中线上分布的散乱数据点的自然样条的局部插值基,并证明了这个基等价于自然样条的截幂基,给出了这些基函数的局部紧支集。做出了算法并且给出了算例,效果良好。     

Clustering Random Curves Under Spatial Interdependence With Application to Service Accessibility

Service accessibility is defined as the access of a community to the nearby site locations in a service network consisting of multiple geographically distributed service sites. Leveraging new statistical methods, this article estimates and classifies service accessibility patterns varying over a large geographic area (Georgia) and over a period of 16 years. The focus of this study is on financial services but it generally applies to any other service operation. To this end, we introduce a model-based method for clustering random time-varying functions that are spatially interdependent. The underlying clustering model is nonparametric with spatially correlated errors. We also assume that the clustering membership is a realization from a Markov random field. Under these model assumptions, we borrow information across functions corresponding to nearby spatial locations resulting in enhanced estimation accuracy of the cluster effects and of the cluster membership as shown in a simulation study. Supplementary materials including the estimation algorithm, additional maps of the data, and the C++ computer programs for analyzing the data in our case study are available online.     

彩色面阵CCD光电系统在白血球自动识别中的应用研究

近年来,彩色面阵CCD的发展尤为引人注目。单片式彩色面阵CCD避免了二片、三片式的芯片多、成本高、信号不易处理的缺点,成为彩色面阵CCD发展的主流。目前,国外单片式彩色面阵CCD已达到实用阶段。我们把彩色面阵CCD应用于显微图象处理,建立了一套实现白血球自动分类识别的光电系统。     

Plane Problem for Layered Composites with Periodic Array of Interfacial Cracks Under Compressive Static Loading

The current paper addresses the problem of 2-D modelling of the onset of failure process in a layered composite with periodic array of interfacial cracks under static compression along layers. The statement of the problem is based on the most accurate approach, the model of piecewise-homogenous medium. The condition of plane strain state is considered. The shear and the extensional buckling modes are examined. The laminae are modelled by transversally isotropic material (a matrix reinforced by continuous parallel fibres). The complex non-classical failure mechanics problem is solved utilizing finite element analysis. It is found that the 0°-plies volume fraction, the crack length and the mutual position of cracks influence the critical strain in the composite.     

Structural and Phase Transformations in the Ni- and Fe-Based Plasma Coatings Under the Effect of High Energy

Specific features of the structure and phase composition of sprayed coatings were investigated. The main physical and mechanical properties of Ni and Fe based coatings are determined. The variation of the structure on different levels and of the phase composition of coating with the coating process subjected to the effect of strong ultrasound loading are examined. The consequences of laser and electron beam melting sprayed coatings are studied.     

Distribution of Stresses Near Angular Notches on an Orthotropic Elastic Plane Under Conditions of Antiplane Deformation

Materials Science - By using a solution of the antiplane eigenvalue problem of the theory of elasticity for an elastic orthotropic wedge, we construct the distribution of singular stresses and...     

A Method of Feature Extraction on Recovery Curves for Fast Recognition Application With Metal Oxide Gas Sensor Array

In the fast recognition applications of electronic nose, not only the recognition time is important, another parameter response-recovery time also needs to be considered. The response-recovery time could be defined as the time from the beginning of measuring one sample to the state of being ready for new sample measurement. An electronic nose with nine metal oxide (MOX) gas sensors and a method of feature extraction on sensor recovery curves were presented in this paper. The electronic nose was designed to reduce the recognition time and the response-recovery time synchronously. In the sampling module of the electronic nose, there were two pumps, which could let the sensor quickly recovered. The feature extraction method could rapidly extract features from sensor recovery curves with robust information. Nine volatile organic compounds (VOCs) gas samples were measured with the electronic nose. The correct recognition ratios under 10 and 15 s recognition time are 91.0% and 95.8%, respectively. The mean response-recovery time of these sensors in the measurements was 33.5 s, which was about 42.7% of the response-recovery time in typical traditional gas sample measurements. The results show that the proposed feature extraction method could extract robust information with short recognition time and response-recovery time.