Sink placement on a 3D terrain for border surveillance in wireless sensor networks

With their distributed nature and redundant operation capability, wireless sensor networks are very suitable for border surveillance scenarios that track intruders trying to breach to a safe side. In such scenarios, keeping the operation going on for as long as possible is the most important aspect of the network. We propose that by placing sink at a carefully selected coordinate will results in a longer living network. We also place restrictions on the candidate locations so that the sensing quality of the network is above a useful predetermined value and the sink is placed in a relatively safe location to avoid destruction. In order to find the suitable coordinates we propose a modified lifetime metric which takes quality and safety measures into account. We also propose a genetic algorithm which uses a discrete event simulator-in-the-loop over a three dimensional terrain to find locations for the sink that fits the given quality and safety restrictions. Using a three dimensional underlying terrain makes the proposed approach more realistic. The results obtained for various sensor network scenarios indicate that the proposed algorithm can find locations that increase the lifetime by also considering the sensing quality and safety.     

A new method of mesh simplification for 3-Dimension terrain using Laplace operator

This paper proposes a new method to simplify mesh in 3D terrain.The 3D terrain is presented by digital elevation model.First,Laplace operator is introduced to calculate sharp degree of mesh point,which indicates the variation trend of the terrain.Through setting a critical value of sharp degree,feature points are selected.Second,critical mesh points are extracted by an recursive process,and constitute the simplified mesh.Third,the algorithm of linear-square interpolation is employed to restore the characteristics of the terrain.Last,the terrain is rendered with color and texture.The experimental results demonstrate that this method can compress data by 16% and the error is lower than 10%.     

基于二叉树和GPU的无缝地形场景渲染方法

设计了一种基于图形处理器(GPU)的无缝地形渲染方法。该方法基于二叉树构建多层次地形网格,该网格用基于行、列号的地形模板表示。在设计过程中,将高程数据转化为适于GPU读取的高程纹理图,再通过顶点纹理提取(VTF)技术从纹理图中采样出高程值用于渲染,整个过程在GPU端完成,提升了地形数据访问效率。同时,采用实时优化自适应网格(ROAM)算法的强制拆分法,通过控制相邻地形块的等级来消除裂缝。最后,采用TriangleStrip方式进行渲染,避免了相邻三角形中顶点坐标数据的重复传递,减少了传递到GPU的数据量。用两块地形数据对算法渲染效率进行了检验,并将算法与Clipmap算法进行了帧率对比。结果表明,该算法有效解决了分块数据的裂缝问题,达到了交互式地形渲染的要求。     

基于贝叶斯核主成分分析的远距离地形标记方法

由于非结构化室外场景外观特征分布存在动态不确定性以及映射偏移特性,因此在室外移动机器人自主导航的过程中采用预确定外观特征并不能非常有效地进行地形标记.为了解决此问题,提出了基于贝叶斯核主成分分析(BKPCA)的远距离地形标记方法.该方法融合了基于贝叶斯公式的聚类中心后验概率,且采用自定义的核函数,实现了原始特征数据结构在低维空间上的保持,能够提取出适合当前场景地形标记的外观特征.实验结果表明,BKPCA模型有效地提高了远距离地形标记的精度.     

基于神经网络的地形匹配方法研究

提出了基于神经网络实现多特征融合的地形匹配算法，充分利用地形的各种不同的统计特征和几何特征，构造了一种地形匹配网络模型．通过对实时图和基准图的分析，给出了计算网络节点之间的权值函数，建立了网络系统能量方程，通过求系统的最小能量得到最佳匹配位置．由于网络能融合地形的不同统计特征和几何特征，所以算法大大提高了系统的抗干扰能力和定位精度，适合于实时图容易发生畸变的地形匹配领域．实验结果表明，定位精度和抗干扰能力均优于传统的地形匹配方法．     

全面预算在企业管理中的实施

本文主要从全面预算的角色定位、预算的目标导向、预算、核算与考核同步协调、预算管理的预警机制等方面对预算管理进行阐述,探讨预算管理对于提升企业管理水平的作用和具体实施办法。     

地形三维可视化的实现与应用

文中讨论了地形三维可视化的原理，详细介绍了高级编程语言与OpenGL结合开发环境下的地形三维可视化的计算机实现过程。在此基础之上，讨论了基于GRID DEM的应用分析功能的实现,包括等高线、坡度图、通视分析以及淹没分析。为三维地形可视化的实施提出了有效的方案。     

小波分析在三维地形数据简化中的应用研究

研究了小波分析在三维地形数据简化中的应用。在分析了小波多分辨率分析理论的基础上,重点探讨了小波多分辨率分析理论在三维地形简化中的应用,提出了实现三维地形数据简化的一种新的方法。     

Rough Terrain Autonomous Mobility—Part 1: A Theoretical Analysis of Requirements

A basic requirement of autonomous vehicles is that of guaranteeing the safety of the vehicle by avoiding hazardous situations. This paper analyses this requirement in general terms of real-time response, throughput, and the resolution and accuracy of sensors and computations. Several nondimensional expressions emerge which characterize requirements in canonical form.The automatic generation of dense geometric models for autonomously navigating vehicles is a computationally expensive process. Using first principles, it is possible to quantify the relationship between the raw throughput required of the perception system and the maximum safely achievable speed of the vehicle. We derive several useful expressions for the complexity of terrain mapping perception under various assumptions. All of them can be reduced to polynomials in the response distance.The significant time consumed by geometric perception degrades real-time response characteristics. Using our results, several strategies of active geometric perception arise which are practical for autonomous vehicles and increasingly important at higher speeds.     

基于复杂地形上三角网数字地面模型的建立

本文提出了一种生成三角网数字地面模型的新方法，它首先利用凸多边形的性质与凸锥的特性来将离散点连成一三角网，计算工作特别快速有效；其次在三角网形成过程中，能将特征信息线作为三角形的边参加构网并采用了优化手段来优化三角网的现状。该方法能有效地限制狭长三角形的出现，并使生成的三角网能密贴地面，真实反映出地表形状。与其它算法相比，该方法具有思路简单明了、成网速度快、编程容易及成网质量高的特点。实际应用表明