FIXED POINTS OF NONEXPANSIVE MAPPINGS ON STAR-SHAPED SUBSETS OF A CONVEX METRIC SPACE

In this paper, we give some characteristic properties of star-shaped sets which include a subset of a convex metric space. Using the characteristic properties, we discuss the existence problems of fixed points of nonexpansive type mappings on star-shaped subsets of convex metric spaces, which generalize the recent results obtained by Ding Xie-ping, Beg and Azam. Finally, we give an example which shows that our generalizations are essential.

Star-shaped Differentiable Functions and Star-shaped Differentials

Based on the isomorphism between the space of star-shaped sets and the space of continuous positively homogeneous real-valued functions, the star-shaped differential of a directionally differentiable function is defined. Formulas for star-shaped differential of a pointwise maximum and a pointwise minimum of a finite number of directionally differentiable functions, and a composite of two directionaUy differentiable functions are derived. Furthermore, the mean-value theorem for a directionaUy differentiable function is demonstrated.

Fruit shape detection by level set

A novel approach for fruit shape detection in RGB space was proposed,which was based on fast level set and Chan-Vese model named as Modified Chan-Vese model(MCV) . This new algorithm is fast and suitable for fruit sorting because it does not need re-initializing. MCV has three advantages compared to the traditional methods. First,it provides a unified frame-work for detecting fruit shape boundary,and does not need any preprocessing even though the raw image is noisy or blurred. Second,if the fruit has different colors at the edges,it can detect perfect boundary. Third,it processed directly in color space without any transformations that may lose much information. The proposed method has been applied to fruit shape detection with promising result.

The shape optimization of the arterial graft design by level set methods

The goal of the arterial graft design problem is to find an optimal graft built on an occluded artery, which can be mathematically modeled by a fluid based shape optimization problem. The smoothness of the graft is one of the important aspects in the arterial graft design problem since it affects the flow of the blood significantly. As an attractive design tool for this problem, level set methods are quite efficient for obtaining better shape of the graft. In this paper, a cubic spline level set method and a radial basis function level set method are designed to solve the arterial graft design problem. In both approaches, the shape of the arterial graft is implicitly tracked by the zero-level contour of a level set function and a high level of smoothness of the graft is achieved. Numerical results show the efficiency of the algorithms in the arterial graft design.

Active Contours and Mumford-Shah Segmentation Based on Level Sets

This paper is to detect regions (objects) boundaries, also to isolate and extract individual components from a medical image. This can be done using an active contours to detect regions in a given image, based on techniques of curve evolution, Mumford Shah functional for segmentation and level sets. The paper classified the images into different intensity regions based on Markov random field, then detected regions whose boundaries are not necessarily defined by gradient by minimizing an energy of Mumford Shah functional for segmentation which can be seen as a particular case of the minimal partition problem. In the level set formulation, the problem becomes a mean curvature flow like evolving the active contour, which will stop on the desired boundary. The stopping term does not depend on the gradient of the image, as in the classical active contour and the initial curve of level set can be anywhere in the image, and interior contours are automatically detected. The final image segmentation is one closed boundary per actual region in the image.

Buckling Optimization of Curved Grid Stiffeners through the Level Set Based Density Method

Stiffened structures have great potential for improvingmechanical performance,and the study of their stability is of great interest.In this paper,the optimization of the critical buckling load factor for curved grid stiffeners is solved by using the level set based density method,where the shape and cross section(including thickness and width)of the stiffeners can be optimized simultaneously.The grid stiffeners are a combination ofmany single stiffenerswhich are projected by the corresponding level set functions.The thickness and width of each stiffener are designed to be independent variables in the projection applied to each level set function.Besides,the path of each single stiffener is described by the zero iso-contour of the level set function.All the single stiffeners are combined together by using the p-norm method to obtain the stiffener grid.The proposed method is validated by several numerical examples to optimize the critical buckling load factor.

基于PS-Level Set的嘴唇几何形状定位模型

针对面向唇读的水平集模型在嘴唇分割中存在边界过收敛和过早收敛的问题,文中提出了一种改进的基于先验知识的水平集模型(简称为PS-Level Set)来进行嘴唇几何形状的定位.PS-Level Set模型利用改进的差值能量函数引入嘴唇形状的先验信息.在曲线演化过程中,反复比较演化曲线和先验曲线的差距,使曲线的演化形状逐渐逼近先验模型形状,从而更精确地收敛于目标物体实际轮廓.实验表明,用PS-Level Set模型定位嘴唇几何形状的准确率比用水平集模型提高了8.38%.

基于多尺度统计形状模型的Levelset分割方法

提出并建立了一种基于小波分析的多尺度统计模型,将该统计模型作为先验知识引入Mumford-Shah能量约束函数,从而指导水平集函数进行图像分割。实验表明,当对拓扑结构复杂的医学图像进行分割时,该方法具有明显的效果,同时分割速度和精度都得到了明显改善。

基于目标监督的先验形状level set模型分割心脏MR图像

提出一种基于目标监督的先验形状level set模型分割心脏MR图像的方法。该方法先根据目标灰度的特征生成特征图像,使得特征图像目标区域灰度趋于一致,再在特征图像的基础上利用先验形状信息的水平集模型对目标进行分割。实验结果表明,该方法能够有效地分割心脏MRI图像。

Shapely值法解决邢台市合作建污水厂费用的合理分担问题

提出将Shapely值方法用于解决污水处理费用的合理分担问题,以河北省邢台市沿河三区合作建污水厂为例进行详细计算和具体分析,得出科学合理的费用分担方案。

Regression Analysis of a Kind of Trapezoidal Fuzzy Numbers Based on a Shape Preserving Operator

Fuzzy regression provides more approaches for us to deal with imprecise or vague problems. Traditional fuzzy regression is established on triangular fuzzy numbers, which can be represented by trapezoidal numbers. The independent variables, coefficients of independent variables and dependent variable in the regression model are fuzzy numbers in different times and TW, the shape preserving operator, is the only T-norm which induces a shape preserving multiplication of LL-type of fuzzy numbers. So, in this paper, we propose a new fuzzy regression model based on LL-type of trapezoidal fuzzy numbers and TW. Firstly, we introduce the basic fuzzy set theories, the basic arithmetic propositions of the shape preserving operator and a new distance measure between trapezoidal numbers. Secondly, we investigate the specific model algorithms for FIFCFO model (fuzzy input-fuzzy coefficient-fuzzy output model) and introduce three advantages of fit criteria, Error Index, Similarity Measure and Distance Criterion. Thirdly, we use a design set and two reference sets to make a comparison between our proposed model and the reference models and determine their goodness with the above three criteria. Finally, we draw the conclusion that our proposed model is reasonable and has better prediction accuracy, but short of robust, comparing to the reference models by the three goodness of fit criteria. So, we can expand our traditional fuzzy regression model to our proposed new model.

Analysis on a Set of 12-parameter Rectangular Plate Element with High Accuracy

It is proved that the so-called a set of 12-parameter rectangular plate elements with high accuracy constructed by using double set parameter method and undetermined method are, in fact, the same one; the real shape function space is nothing but the Adini＇s element＇s, which has nothing to do with the other high degree terms and leads to a new method for constructing the high accuracy plate elements. This fact has never been seen for other conventional and unconventional, conforming and nonconforming rectangular plate elements, such as Quasi-conforming elements, generalized conforming elements and other double set parameter finite elements. Moreover, such kind of rectangular elements can not be constructed by the conventional finite element methods.

不同形状的珊瑚砂颗粒沉降试验研究

珊瑚砂在液体中的沉速是反映泥沙运动特性的一个重要物理量。由于珊瑚砂形状多样,套用现有的珊瑚砂沉速公式进行计算并不合适。针对珊瑚砂颗粒开展形状分析,将珊瑚砂颗粒分成枝棒状、片状和块状3种形状,然后开展单颗粒沉降试验。基于试验数据,分析不同形状珊瑚砂颗粒的沉降特性,与各家理论公式计算结果进行比较分析,选取经典的珊瑚砂颗粒沉速公式,引入颗粒形状系数进行公式修正,从而推求了枝棒状、片状和块状珊瑚砂颗粒的阻力系数和沉降速度公式。该公式充分考虑不规则珊瑚砂颗粒形状的影响,具有更高的计算精度和适用性。

基于形状文法的荆楚青铜酒具重构设计

对传统荆楚青铜酒具的造型研究,通过对其风格演变与器型、纹饰特征进行分析,结合当下对白酒酒具设计新的需求进行实践。运用文献研究法和形状文法对荆楚青铜酒具元素进行提取、转换,通过案例实践分析传统酒具造型运用于现代白酒酒具的设计路径。构建出荆楚传统青铜酒具的创新形态及推演设计过程,丰富现代白酒酒具设计的文化内涵,为同类产品设计研究提供过程参考。

乡村振兴战略省际扩散的时空演进、影响因素及提升路径

基于213份省级政策文本,系统分析了乡村振兴战略省际扩散的时空演进机理,并通过模糊集定性比较分析(fsQCA)方法剖析乡村振兴战略省际扩散的影响因素及路径。研究结果表明,时间上,高位推动使得乡村振兴战略省际扩散曲线呈R型,表现出初期急剧爆发、后期趋缓饱和的特征;空间上,在多中心效应、层级效应和邻近效应的作用下,乡村振兴战略省际扩散整体呈现出由南向西推进的趋势;从影响因素来看,乡村振兴战略省际扩散是多个因素共同作用的结果,且正、反向结果与影响因素组合之间存在着非对称关系;就路径而言,基于核心条件归纳出了4种乡村振兴战略高扩散路径,分别是双重需求型、个人特质型、社会压力型以及经济基础型。基于此,为推动乡村振兴战略省际扩散的持续深入,提出提升信息技术应用水平、增加地方官员异地调任经历、发挥公众和社会舆论的作用、大力发展地区经济等建议。

高层结构-混联Ⅱ型惯容阻尼耗能体系减震性分析

针对高层结构中设置混联Ⅱ型惯容阻尼器组成耗能体系的随机响应分析复杂的问题,提出了结构位移及阻尼器阻尼力响应的封闭解,并基于所获得的封闭解探究了实模态振型数对分析精度的影响和在原结构层间位移超限楼层设置阻尼器能有效减震的布置策略。首先,根据混联Ⅱ型惯容阻尼器力学构造图及设置方式,建立阻尼器阻尼力与结构节点水平位移的微分型本构关系进而重构耗能体系的地震动方程。其次,利用实模态解耦法获得高层结构简明等效的动力学参数,运用功率谱二次式分解法推导出结构节点相对于地面的绝对位移、竖向构件层间位移及阻尼器阻尼力等响应的功率谱精确二次式解进而推导出耗能体系基于双过滤白噪声激励下系列响应的0~2阶谱矩简明封闭解。最后,通过算例,验证了所提封闭解的正确性;研究了实模态振型数对系列响应谱矩分析精度的影响和阻尼器设置位置对结构减震效果的影响。研究表明:对于多自由度结构响应分析时,建议采用原结构自由振动分析时质量参与系数累计达100%时所对应的振型数,可获得稳定的精度和提高大型复杂结构设置混联Ⅱ型惯容阻尼器的响应的分析效率;通过在原结构层间位移超限楼层或连续多层层间位移超限的楼层中间隔一层设置参数合适的混联Ⅱ型惯容阻尼器可有效降低结构的地震动响应,所提惯容阻尼器设置策略具有较好的经济性。所提解析解和惯容系统在高层结构的设置策略可为混联Ⅱ型惯容阻尼器在实际工程应用中提供有益的参考价值。

某U型盾构装配式预制综合管廊研究及设计

本文针对雄安新区某整节段预制拼装综合管廊U型盾构施工进行相关设计计算。通过试验确定垫层及侧缝回填材料配比。侧缝回填采用拌制速凝液态土,可实现快速回填,在保证已安装管节边坡稳定的同时具备一定的阻水效果。U盾总推力确定是保证工程顺利实施的关键,本文充分考虑土层的弹塑性材料特性,分析计算欠挖土体破裂滑动面,采用有限元方法对U型盾构机底部欠挖土体切削反力进行了数值模拟分析,对土体能够提供的总推力作准确计算。相关内容可为同类工程提供参考。

‘京白梨’果形及果重差异影响因素分析

为解决‘京白梨’品质退化的问题,以北京地区‘京白梨’结果树为试材,比较不同秋子梨授粉品种、坐果序位和立地条件(丘陵和平地果园)对‘京白梨’果形和果重的影响。结果表明,利用‘子母梨’、‘山梨’、‘鸭广梨’、‘金香水’和‘寒红’分别给‘京白梨’授粉,‘山梨’、‘寒红’授粉效果最佳,获得的‘京白梨’果重分别为113.60、110.80 g,果形指数均为0.82;3~5序位坐果率高、果重大,优于1~2序位和6~9序位坐果;山地丘陵果园‘京白梨’果重100.77 g、果形指数0.82,而平地果园果重125.08 g、果形指数0.87,果形指数受立地条件影响。综上所述,为保证‘京白梨’果形的典型性,可配置‘山梨’和‘寒红’为授粉品种,疏果保留3~5序位,并在冷凉山区环境种植。

平乐郭氏正骨手法配合钢针撬拨复位治疗MasonⅡ型桡骨头骨折临床观察

目的:观察平乐郭氏正骨手法配合钢针撬拨复位治疗型桡骨头骨折的临床疗效。方法:选择MasonⅡ型桡骨头骨折患者68例,分为观察组37例和对照组31例,在常规术前冷疗、术后石膏固定等治疗基础上,对照组取切开复位微T形钛板内固定术,观察组采用平乐郭氏正骨手法配合钢针撬拨复位固定术。统计对比两组患者手术时间、术中出血量、住院时间、疼痛评分、肘关节功能Broberg-Morrey评分,并评价两种治疗方法安全性。所有患者随访1年。结果:经治疗,两组患者的疼痛评分均较治疗前降低,Broberg-Morrey评分均升高(P<0.05)。组间比较,观察组的手术时间、住院时间均较对照组短,术中出血量少于对照组,术后各个时间点的疼痛评分均低于对照组,Broberg-Morrey评分均高于对照组(均P<0.05)。在安全性方面,两组患者均未发生术后感染、神经损伤等严重并发症,观察组患者术后内固定物克氏针失效2例,对照组延迟愈合1例、骨化性肌炎1例,两组比较,差异无统计学意义(P>0.05)。结论:平乐郭氏正骨手法配合钢针撬拨复位固定治疗MasonⅡ型桡骨头骨折能获得良好的功能复位,达到骨折临床愈合,减少手术创伤,尽快恢复肘关节功能。

物体轮廓形状超像素图割快速提取方法

提出一种水平集框架下物体轮廓形状超像素图割快速提取方法.该方法首先均匀化放置种子点,通过对超像素化演化力的设定,生成具有区域相似特征的超像素,这些超像素对原图像的划分既能保持目标轮廓形状的几何特性,又可避免超像素间的互相重叠.然后构建超像素标号和Heaviside函数的关联关系,应用图割建立M-S能量函数的优化模型.最终利用超像素图割提取目标轮廓的几何形状.实验表明,超像素化的图像像素数目大幅度减少,转化后的优化模型符合图割对能量函数进行优化的要求,图割中最小割/最大流方法避开微分方程的求解,这些措施在保证轮廓形状提取效果的基础上提高提取效率.