基于Delaunay三角剖分的地表平均温度模拟

利用Delaunay三角网对目标区域进行剖分,在对地表温度进行高度插值后,运用二重积分的思想建立了基于Delaunayr三角剖分的地表平均温度测量模型.同时以南极地表平均温度的测量为例,将67个自动气象地表台站、46个气象地表台站以及56个高空气象观测站的加权平均温度与地表平均温度的数据进行分析,得到南极2015全年地表平均温度均在-8℃以下,最低温约为-20℃,符合南极大陆地表温度的实际情况.     

An efficient adaptive analysis procedure for node-based smoothed point interpolation method (NS-PIM)

This paper presents an efficient adaptive analysis procedure being able to operate in the framework of the node-based smoothed point interpolation method (NS-PIM). The NS-PIM uses three-node triangular cells and is very easy to be implemented, which make it an ideal candidate for adaptive analysis. In the present adaptive procedure, a new error indicator is devised for NS-PIM settings; two ways are proposed to calculate the local critical value; a simple h-type local refinement scheme is adopted and Delaunay technology is used for regenerating optimal new mesh. A number of typical numerical examples involving stress concentration and solution singularities have been tested. The results demonstrate that the present procedure achieves much higher convergence rate results compared to the uniform refinement, and can obtain upper bound solution in strain energy.     

基于RSSI梯度的AP定位算法(英)

Recent rapid rise of indoor location based services for smartphones has further increased the importance of precise localization of Wi-Fi Access Point(AP).However,most existing AP localization algorithms either exhibit high errors or need specialized hardware in practical scenarios.In this paper,we propose a novel RSSI gradient-based AP localization algorithm.It consists of the following three major steps:firstly,it uses the local received signal strength variations to estimate the direction(minus gradient) of AP,then employs a direction clustering method to identify and filter measurement outliers,and finally adopts triangulation method to localize AP with the selected gradient directions.Experimental results demonstrate that the average localization error of our proposed algorithm is less than 2meters,far outperforming that of the weighted centroid approach.     

基于节点安全预测的火场撤离路径规划

火场烟雾弥漫、能见度低,消防队员很难准确定位并找寻到合适的撤离路径.文中使用人机协作在火场中建立动态三角网基础上,以网络节点为参考点为消防员规划撤离路线.该方案使用基于相似函数的证据理论对火场中各节点采集的烟雾浓度、温度、氧气浓度进行数据融合,并确定节点位置的安全等级;引入预测机制,可以预测短时间内前进路径中节点位置的安全等级的变化.根据安全等级变化,剔除网络中危险节点,使用基于路程换算的A算法计算实时最短的安全路径.通过数据分析表明,该方案能更好的适应火场环境多变的特点.     

激光三角位移计接收光功率与被测表面倾斜的关系及倾斜角测量

以激光在粗糙物体表面的散射理论为基础．详细讨论了被测表面倾斜与激光三角位移计接收光功率的关系，在此基础上提出了在测位移的同时测量该倾斜角的方法．给出了计算机模拟及实测的结果。     

一种关于大位移激光三角法测量参数标定方法的研究

本文介绍了怎样用逼近法来标定激光三角法测大位移中的参数，逼近法是基于最小二乘法原理，标定参 数精确性高．     

Pathwidth of outerplanar graphs

We are interested in the relation between the pathwidth of a biconnected outerplanar graph and the pathwidth of its (geometric) dual. Bodlaender and Fomin [3], after having proved that the pathwidth of every biconnected outerplanar graph is always at most twice the pathwidth of its (geometric) dual plus two, conjectured that there exists a constant c such that the pathwidth of every biconnected outerplanar graph is at most c plus the pathwidth of its dual. They also conjectured that this was actually true with c being one for every biconnected planar graph. Fomin [10] proved that the second conjecture is true for all planar triangulations. First, we construct for each p ≥ 1, a biconnected outerplanar graph of pathwidth 2p + 1 whose (geometric) dual has pathwidth p + 1, thereby disproving both conjectures. Next, we also disprove two other conjectures (one of Bodlaender and Fomin [3], implied by one of Fomin [10]. Finally we prove, in an algorithmic way, that the pathwidth of every biconnected outerplanar graph is at most twice the pathwidth of its (geometric) dual minus one. A tight interval for the studied relation is therefore obtained, and we show that all cases in the interval happen. © 2006 Wiley Periodicals, Inc. J Graph Theory 55: 27–41, 2007     

Bivariate quartic spline spaces and quasi-interpolation operators

In this paper, we study two bivariate quartic spline spaces and , and present two classes of quasi-interpolation operators in the two spaces, respectively. Some results on the operators are given.     

Detection of discontinuities in scattered data approximation

A Detection Algorithm for the localisation of unknown fault lines of a surface from scattered data is given. The method is based on a local approximation scheme using thin plate splines, and we show that this yields approximation of second order accuracy instead of first order as in the global case. Furthermore, the Detection Algorithm works with triangulation methods, and we show their utility for the approximation of the fault lines. The output of our method provides polygonal curves which can be used for the purpose of constrained surface approximation. This revised version was published online in June 2006 with corrections to the Cover Date.     

The flow complex: A data structure for geometric modeling

We study a special case of the critical point (Morse) theory of distance functions namely, the gradient flow associated with the distance function to a finite point set in . The fixed points of this flow are exactly the critical points of the distance function. Our main result is a mathematical characterization and algorithms to compute the stable manifolds, i.e., the inflow regions, of the fixed points. It turns out that the stable manifolds form a polyhedral complex that shares many properties with the Delaunay triangulation of the same point set. We call the latter complex the flow complex of the point set. The flow complex is suited for geometric modeling tasks like surface reconstruction.