Reconstruction of convergent smooth B-spline surfaces

Recently, there have been improvements on reconstruction of smooth B-spline surfaces of arbitrary topological type, but the most important problem of smoothly stitching B-spline surface patches (the continuity problem of B-spline surface patches) in surface reconstruction has not been solved in an effective way. Therefore, the motivation of this paper is to study how to better improve and control the continuity between adjacent B-spline surfaces.

In this paper, we present a local scheme of constructing convergent G¹ smooth bicubic B-spline surface patches with single interior knots over a given arbitrary quad partition of a polygonal model. Unlike previous work which only produces (non-controllable) toleranced G¹ smooth B-spline surfaces, our algorithm generates convergent G¹ smooth B-spline surfaces, which means the continuity of the B-spline surfaces tends to G¹ smoothness as the number of control points increases. The most important feature of our algorithm is, in the meaning of convergent approximation order, the ability to control the continuity of B-spline surfaces within the given tolerance and capture the geometric details presented by the given data points.     

Sources of cumulative continuity in personality: A longitudinal multiple-rater twin study.

This study analyzed the etiology of rank-order stability and change in personality over a time period of 13 years in order to explain cumulative continuity with age. NEO five-factor inventory self- and peer report data from 696 monozygotic and 387 dizygotic twin pairs reared together were analyzed using a combination of multiple-rater twin, latent state-trait, and autoregressive simplex models. Correcting for measurement error, this model disentangled genetic and environmental effects on long- and short-term convergent valid stability, on occasional influences, and on self- and peer report-specific stability. Genetic factors represented the main sources that contributed to phenotypic long-term stability of personality in young and middle adulthood, whereas change was predominantly attributable to environmental factors. Phenotypic continuity increased as a function of cumulative environmental effects, which became manifest in stable trait variance and decreasing occasion-specific effects with age. This study's findings suggest a complex interplay between genetic and environmental factors resulting in the typical patterns of continuity in personality across young and middle adulthood. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lipschitz properties of the attainable set of singularly perturbed linear systems

We consider a linear control system containing a small positive parameter η in a part of the derivatives. It is shown that for every ε (0,1) the map: η → attainable set, is Lipschitz continuous with exponent .     

粗糙概念格及构造算法

概念格是数据分析与知识提取的一种有效工具,具有精确性和完备性等特点。针对决策形式背景,采用粗集理论中近似的方法描述格的内涵所拥有的外延,给出了一种粗糙概念格结构,具备了描述不确定知识的能力,在此基础上,给出了粗糙概念格的构造算法CARCL。     

GC 1 multisided Bézier surfaces

This paper presents a new method for generating a tangent-plane continuous (GC¹) multisided surface with an arbitrary number of sides. The method generates piecewise biquintic tensor product Bézier patches which join each other with G¹-continuity and which interpolate the given vector-valued first order cross-derivative functions along the boundary curves. The problem of the twist-compatibility of the surface patches at the center points is solved through the construction of normal-curvature continuous starlines and by the way the twists of surface patches are generated. This avoids the inter-relationship among the starlines and the twists of surface patches at the center points. The generation of the center points and the starlines has many degrees of freedom which can be used to modify and improve the quality of the resulting surface patches. The method can be used in various geometric modeling applications such as filling n-sided holes, smoothing vertices of polyhedral solids, blending multiple surfaces, and modeling surface over irregular polyhedral line and curve meshes.     

改进贝叶斯分类算法在入侵检测中的研究

把朴素贝叶斯分类算法引入到入侵检测中,可以简单方便地区别出入侵事件。但是由于该算法在学习中存在一定的不足和缺陷,主要是属性值之间要求相互条件独立和训练集数据不完备这两个缺陷,导致了它的检测效果并不是很理想。文中针对该算法这两个最主要的缺陷,提出增量学习概念,引入损失幅度参数,改进和完善朴素贝叶斯分类算法。并对改进后的新学习策略进行了分析和研究,给出了其基本实现思想和算法描述,并指出它实现的可能性。     

T-Bézier曲线及G1拼接条件

针对目前NURBS模型的局限性问题,在对T-Bézier基函数及曲线端点特性分析的基础上,提出了k次T-Bézier基函数的表达式,通过重新参数化使其参数区间范围规范为[0,1],给出了椭圆弧和心脏线的T-Bézier表示,并给出T-Bézier曲线间G1拼接的几何条件,所得结论具有明确的几何意义,能够较好地应用于曲面造型中。     

Improvement of free-form surfaces for product styling applications

There are a number of ways of describing free-form surfaces within geometric modelling systems. For product styling and related activities, there is a need to ensure that surface quality is good and that patches join together smoothly. Additional parameters can be introduced to allow surfaces to be modified. This raises the question of whether these can be chosen automatically, and this in turn requires measures of what is a ‘fair’ surface. Measures based on surface curvature are discussed and applied to adjust surface patches presented in terms of point meshes.     

基于量子粒子群优化算法的结构损伤识别

提出一种以广义柔度矩阵为损伤指标,基于量子粒子群优化算法的结构损伤识别方法.该方法根据结构损伤前后广义柔度矩阵差与结构物理参数变化关系,将结构广义柔度矩阵识别问题转化为优化问题,进而采用系统辨识能力较强的量子粒子群优化算法搜索目标函数最优值,从而达到损伤位置和损伤程度同时识别的双重效果.最后通过简支梁数值模拟对该方法的有效性进行了验证.     

基于邻域滤波的图像修复

图像修复是图像恢复研究中的一个重要内容,它的目的是根据图像现有的信息来自动恢复丢失的信息,可以用于对旧图片的修复。大多数现有图像修复算法都非常复杂,而且难于实现。由于图像中的边缘代表了图像的重要信息,所以在设计修复算法时,必须着重考虑边缘的恢复。提出了一种基于图像邻域滤波算法、利用图像的空间连续性,及图像的边缘信息的图像修复算法。该算法实现简单,修复速度快,对小区域的修复效果较好。