上海南站钢屋盖Y形主梁极限承载力分析

上海南站是国内外第一座大型圆形火车站建筑,该建筑屋盖为预应力索梁结构体系,大跨度钢梁特殊的平面呈Y形,截面为橄榄形薄壁闭口截面,使结构设计有较大难度。介绍了结构局部模型边界条件的确定方法,运用大型有限元分析软件MSC.MARC详细分析了该梁的极限承载力,为该结构设计提供了可靠的计算依据,为此类结构的分析提供有价值的参考资料。计算结果表明,只有综合考虑结构的几何和材料非线性才能准确评估出结构的极限承载力。     

非接触眼压计的人眼瞳孔定位算法研究

为了提高非接触眼压计自动化程度,加快人眼瞳孔定位效率,提出了一种采用基于XLD轮廓的多模板匹配算法,可实现对人眼瞳孔快速精确定位,并增加了非接触眼压计瞳孔定位检测范围,提高了自动化水平。同时对误检图像,采用了双边滤波、阈值分割和腐蚀膨胀处理,再通过设定参数得到瞳孔区域,最后使用Hough变换实现对误检图像的重新定位。实验结果表明,所提出的方法的定位成功率在99%以上,误差在5像素以内,平均定位为0.121s,能够精准、快速的得到人眼瞳孔的中心坐标,可以满足非接触眼压计对瞳孔精确定位和快速定位的要求,同时对个体瞳孔差异、姿态差异、瞳孔部分被遮挡、边缘光斑影响等干扰因素有较强的鲁棒性和泛化性。     

铁四院生产科研大楼深基坑支护设计与施工综述

在铁四院生产科研大楼深基坑工程中成功应用了2层椭圆形组合结构内支撑,并实现了椭圆环内主楼区域在其周边地下室尚未施工完毕的情况下提前施工至地上的意图,加快了主体结构的施工进度,圆满实现了社会及经济效益。     

Why higher resolution graphics cards are needed in colour vision research

The colour resolution of a 14‐bit and an 8‐bit per channel graphics card were evaluated and compared with the just noticeable difference between colours (varying only in luminance) for: (1) a standard observer (based on the CIE 1976 L*u*v* colour space) and (2) real observers in a colour discrimination task. The results of this study show that an 8‐bit per channel graphics card seems adequate for colour discrimination experiments where stimuli only vary in luminance. However, considering that the resolution of the graphics card should be equal to the Nyquist rate, an 8‐bit per channel card turns out to be inadequate. For colour discrimination experiments where stimuli only vary in chromaticity, there is an undersampling of the colour space with respect to MacAdam ellipses when using 8‐bit per channel graphics cards. The extremely fine colour resolution of a 14‐bit per channel graphics card overcomes these problems. Its use allows more accurate measurements of achromatic and chromatic discrimination thresholds and avoids experimental (spatial or luminance) artefacts, such as bandings that can occur on achromatic or chromatic gradients. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2011     

透视仿射变换在轴测椭圆中的应用与分析

本文介绍透视仿射交换在轴测椭圆中的应用和作图分析。通过求出对应椭圆的长短轴，可作出实形轴测椭圆。透视仿射交换可用于求两个几何体任意截交线。     

用仿射对应求4点椭圆的方法及应用

本文是应用仿射对应原理,以椭圆曲线上4个点及其中心,求作椭圆的方法。以及用此方法解决某些一般形式的二次曲面中的一些几何作图问题。     

点位方差及误差椭圆的有关问题

本文讨论了在常规测量中应该用平均点位方差来表示待定点的点位精度,在要求较高的工程测量或变形观测中,则要采用某些特定方向的点位方差或置信误差椭圆(球)来进行误差预计或精度评定。     

A Deformable Template Model, with Special Reference to Elliptical Templates

This paper suggests a high-level continuous image model for planar star-shaped objects. Under this model, a planar object is a stochastic deformation of a star-shaped template. The residual process, describing the difference between the radius-vector function of the template and the object, is allowed to be non-stationary. Stationarity is obtained by a time change. A parametric model for the residual process is suggested and straightforward parameter estimation techniques are developed. The deformable template model makes it possible to detect pathologies as demonstrated by an analysis of a data set of cell nuclei from a benign and a malignant tumour, using stochastic deformations of ellipses.     

等距线方程式的一个推论

本文根据曲线等距线方程式,用反证法证明了椭圆的等距线不是椭圆,用数值计算法验证了这一结论,进而推论出“已知曲线和它的等距线不都是同名曲线。”     

椭圆曲线密码算法在零知识证明方案中的应用

论文结合零知识证明与椭圆曲线密码体制二者的特点,提出了一种新的零知识证明体制,它与安全性基于一般大数分解问题的零知识证明体制相比,在安全性、计算量及通信量等方面具有更大的优势。