简化的

This thesis contributes to geometry compression in the following aspects: Proposes a method of progressive spherical mesh parameterization based on local parameterization by directly projecting the deleted vertices to its neighborhood. Based on spherical mesh paramterization, an adaptive subdivision remeshing method by progressivly redistributing of sampling points is proposed, by this means, the main geometry information of the original mesh can be captured with only a small amount of samples, it can also be used in mesh simplification. By regarding attributes binded on mesh vertices as geometry signals and transferring them onto a uint sphere by means of spherical mesh parameterization, meshes with different attributes are compressed with spherical wavelet successfully with high compression rate. As a kind of lossy geometry compression technique, two mesh simplification algorthimes are also presented in this thesis.

归纳起来，本文的主要贡献有：提出了以直接投影局部参数化方法为基础的网格累进球面参数化方法；在网格球面参数化方法的基础之上，提出了一种基于累进优化布点方案的网格细分采样方法，该方法可以用很少的采样点就可以捕获到网格的主要特征，因此我们也将其用于后面的网格简化工作当中；通过将网格顶点上定义的各种属性看成几何信号，并以网格球面参数化为手段将几何信号迁移到单位球面上，从而成功地实现了用球面小波对各种几何信号的压缩；作为一种有损压缩方法，本文还提出了基于统一距离的网格简化算法和基于重采样的网格简化算法。

Now the triangular mesh model simplification algorithm based on edge collapse is very complex.Combining Garland's quadric error metrics algorithm and Hoppe's progressive mesh algorithm,a new algorithm for triangular mesh dynamic model simplification based on cost function is proposed in this paper.

目前基于边折叠的三角网格模型简化算法边折叠计算复杂，没有有效进行动态简化，结合Garland的二次误差度量算法和Hoppe的累进网格算法，提出了基于代价函数的三角网格模型动态简化算法。

According to the features and analysis of a howitzer ,some components are considered as rigid bodies and some as springs.

根据某火炮的结构特点和分析要求，把一些工程元件简化成刚体，另一些工程元件简化成弹簧，用有限多个质量、转动惯量、弹簧和阻尼形成一个离散的参数系统，从而得到火炮系统的简化模型。

The main research contents are stated asfollow: 1. Simplified analysis method of space grids structuresDouble-layer space grids have been assumed as sandwich plate, and are analyzed bythe nontraditional theory of plate with consideration of shear deformation and threegeneralized displacements. Using the theory of energy variation, simplified methodsfor bending, stability and vibration analysis of double-layer space grids have been putforward based upon the idea of split rigidity. The formulas for calculating internalforces, displacements, critical load and natural frequency have been given out. Set thestable cables and bearing cables in hyperbolic paraboloid cable nets are all replaced bytruss-cable to form truss-cable nets structures. Natural vibration analysis method fortruss-cable nets structures has been put forward using the energy variation method andRayleigh method.

主要内容包括： 1、空间网格结构静动力简化分析方法把网架结构简化为夹层板，采用考虑剪切变形的具有三个广义位移的平板弯曲理论进行分析，基于分解刚度思想利用能量变分原理提出了网架结构弯曲、稳定与振动分析的简化计算方法，给出了位移、内力、屈曲临界荷载和固有频率的计算公式；将双曲抛物面索网中的稳定索与承重索均用劲性索代替形成劲性索网结构，基于能量变分法和Rayleigh法给出了劲性索网结构固有振动分析的简化计算公式。

Furthermore, this paper discusses the movement character and visualization method of rigid body and particle system.

针对海量动态目标的简化和调度，本文引入了层次运动模型的思想，从可见性的判断，模型的简化，运动层次的简化等几个方面对运动刚体的LOD方法作了初步的探讨。

This paper introduces a physical feature-sensitive topological simplification algorithm for planar vector fields to solve the physical feature preserving problem ignored by pre-existing methods. Its central idea is to classify the vector field region under the application-specified physical criterion, and combine the feature detection of a vector field with its topological simplification.

针对现有拓扑简化方法忽略物理特征保持的缺陷，提出一种对物理特征敏感的平面向量场拓扑简化算法，其中心思想是使用为应用定制的物理判据分类向量场区域，将向量场的特征检出与拓扑简化关联起来。

Moreover, the prototype provides multi-levels simplification to create LOD models according to users' conditions, such as hardware, system configuration, for scarifying their requirements. It facilitates creating LOD models of complex building in Virtual Geographic Environments.

通过提供多种参数选择，该原型系统不仅能够按照用户指定的感知简化策略执行各种不同等级的模型简化，创建出满足用户需要的简化模型，而且可以按照用户指定的简化阈值进行简化，为虚拟地理环境建设中的复杂建筑物LOD建模提供了一种新工具。

In order to satisfy the user cognitive demands,the simplification map are used to provide the whole route information which includes only simplification route and the landmarks on the way,and the map display contents are visualized depending on the placename"s ranking;the paper also studies the different simplify principles from traditional map synthesis,that is ,releases the veracities of route geometry elements such as length and angle for the sake that the relative user"s task cognitive informations are displayed with clarity and legible on the limited screen;researches on the route simplify algorithms that preserving the topology-coherence.the paper exploits the application software for LBS navigation service.

在满足用户当前认知需求前提下，提出用简化路线图提供整个路线信息，简化图中包含已简化过的路线和路线两边的地标，而且地图内容可视化依据于地名等级；研究不同于传统制图综合原则的路线认知简化原则，即放松路线中几何元素的准确度，以确保与用户任务相关的道路认知信息最大清晰度地展现在有限屏幕上；研究保持拓扑一致性的快速路线简化算法。

In order to simplify the analysis, the load proportion on templets and skeletons was supposed from the viewpoint of structural safety and construction requirements of the bridge, and the skeletons were simulated by beam elements and loads on skeletons were simplified as concentrated loads.

为简化计算，从结构安全和满足桥梁施工要求出发，合理的假定模板系统及劲性骨架的载荷分担率，劲性骨架简化为空间杆系，载荷简化为节点载荷。

This paper, based on the full scale bird impact tests, and detailed analysis the results of high speed photography, dynamic strain gauge, puts forward that triangle pulse simply model could be simplified by bird impact loading of inclined impact process .

对飞机风挡进行全尺寸鸟撞试验，通过对鸟弹撞击风挡玻璃过程高速摄影、动态应变测量等试验结果的分析，提出了斜撞击过程的鸟撞载荷可以简化为三角形脉冲的简化分析模型，利用该简化载荷模型对风挡玻璃鸟撞进行的有限元分析，结果和试验结果很好地相符

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。