查询词典 parameterization

To construct the parameterization form of reconstruction surface, a new algorithm for the planar parameterization of quadrilateral meshes is presented.

4提出了基于网格简化的四边形网格参数化算法，为构造重建网格的参数曲面提供了新方法。

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。

The method involves an iterative procedure, which incrementally flattens a 3D triangular mesh by region growing and obtains a parameterization with free boundary. The result is then converted to a parameterization with regular boundary by conformal mapping. Our method accounts for both the angle and area distortion during parameterization, it yields a parameterization with less global distortion and no triangular flipping.

采用区域增长算法逐层展平空间三角网格，得到空间三角网格曲面的自由边界的参数化结果，并利用保形变换将自由边界的参数化结果变换为规则边界的参数化结果；同时兼顾了参数化的角度变形和面积变形，使得参数化结果具有整体变形较小的特点，并能够避免三角形折叠的现象。

Properness of a parameterization is a basic property of rational parametric curves and it has been well studied when the coefficients of the parameterization are rational. However, such coefficients in engineering and CAGD are often represented with float numbers with errors.

有理参数曲线的恰当性是曲线的基本性质，虽然其在有理系数情况下已经有完备的结果，但在工程和CAGD应用中常常得到带误差浮点系数的有理表示形式。

By the above four criteria, it is proved that there does not exist a line parameterization which could satisfy all the four criteria at the same time, and that the line parameterization, formulated as c= ax+y, a∈-a0 ,a0, where a0 is an arbitrary positive number, can not only satisfy the uniqueness, boundedness, and recursiveness criteria, but also achieve the best goodness to the uniformness one.

根据上述四条标准，证明了不存在同时满足这四条标准的直线参数化方式t和直线参数化方式c= ax+y， a∈-a0 ，a0不但满足唯一性、有界性和递归性标准，而且可以获得均匀性标准的最优近似。

Using coupling model M4RC3 and improved MM4, a dust storm and a snow storm were simulated respectively. The effects of radiation parameterization and microphysics parameterization on development of dust storm and snow storm mesoscale system were discussed. Dynamical and thermodynamical diagnoses were also carried out to study the developing mechanism on the systems.

用耦合模式M4RC3和引入三相云显式降水方案后改进和发展的中尺度模式MM4分别对西北地区黑风暴和暴雪进行了数值模拟，讨论了模式中辐射参数化和微物理过程参数化对与黑风暴和暴雪相伴的中尺度系统演变的影响，并对这些系统发生、发展的机制进行了动力学和热力学诊断。

Besides, the solution of large equation set can be avoided and the computation efficiency can be increased using the algorithm for the planar parameterization of quadrilateral meshes, so it provides the basis for the reconstruction of parameterization surfaces for quadrilateral meshes.

此外，该方法避免求解大型方程组，提高了计算效率，可为构造重建四边形网格的参数曲面提供有效方法。

An initial spherical parameterization is firstly constructed by lifting planar parameterization to the sphere through the stereographic projection. Then we introduce an efficient approach based on bary centric coordinate to improve the initial spherical parameterization. At last, a uniform spherical parameterization is generated by a Moebius transformation.

通过立体投影将现有的平面参数化方法推广到球面上，得到一个初始的球面参数化；为了减小变形，引入质心坐标进行全局优化；最后用Moebius变换均匀化最终的球面网格。

Main results are given as follows:(1) By means of the parameterization of convective gustiness, the mesoscale enhancement of surface fluxes is included in CAM3, thus, the parameterization scheme of sea surface turbulent fluxes in CAM3 is improved.

本文通过对流性阵风参数化方法，在CAM3原有海气湍流通量参数化方案(CAM3方案)中引入边界层自由对流和降水深对流对海表湍流通量的贡献，改进了CAM3模式的海气湍流通量参数化方案(CAM3 ME方案，简称ME方案)。

The parameterization scheme of sea surface turbulent fluxes in CAM3 (Community A tmosphere Model Version 3) was improved by the parameterization for win d gustiness, which considers the contribution to sea surface fluxes by the bound ary free convective and precipitation convective. The new parameterization schem e is named CAM3 ME scheme.

通过对流性阵风参数化方法，在CAM3原有海气湍流通量参数化方案(CAM3方案)中引入边界层自由对流和降水深对流对海表湍流通量的贡献，改进了CAM3模式的海气湍流通量参数化方案(CAM3 ME方案)。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。