查询词典 algebraic surface

Regularity is an important algebraic property of parametric curve and surface, which depends on the parameterization of parametric curve and surface.

正则性是参数曲线曲面的重要代数性质，是由参数曲线曲面的参数化决定的。

For a general parametric curve/surface, we usually cannot compute its exact implicit form. Even though its exact implicit form can be computed, the curve/surface implicitization involves relatively complicated computation and the degree is higher. Moreover, it may have unexpected components and self-intersections. All these unsatisfied properties limit the applications of the exact implicitization. So finding curve/surface approximate implicitization has become a practical problem. In this paper, we present an algorithm to solve the approximate implicitization of a given parametric curve by using a quadratic algebraic spline curve.

由于精确隐式化过程不一定可以实现，即使可以实现隐式曲线曲面的阶数高计算复杂，并且具有不希望的自交点和奇异分支，从而限制了隐式化的运用，所以寻求参数曲线曲面的近似隐式化问题成为很实际又重要的问题，提出利用二次代数样条曲线来实现一般平面参数曲线近似隐式化的一种算法。

Content: This course discusses the line, plane and quadratic surface in space through algebraic methods, and aims at developing the students' ability to solve geometric problems through analytic methods and to relate geometric intuitive image with algebraic quantitative relation.

主要内容：本课程运用代数方法研究空间解析几何中的直线、平面与二次曲面，培养学生运用解析方法解决几何问题的能力，以及将几何直观形象与代数数量关系相联系的能力。

The algebraic surface fitting is implemented only by computing a generalized eigenvector, so this reconstruction method is computationally efficient.

代数曲面的拟合仅计算一个广义特征向量问题就可以完成，因此这种重建方法的计算效率较高。

Since the visualization of implicit algebraic surface is still a difficult problem, it is doubtlessly meaningful to construct some convenient and effective parameterization method for some kind of concrete implicit surfaces.

由于隐式代数曲面的显示问题始终是困扰人们的一个关键性难题，从而针对具体形式的代数曲面，能给出方便有效的参数化方法无疑是有意义的。

The system of differential equations for a geodesic line on an algebraic surface was discredited into a nonlinear system. Then it was solved numerically based on iterative methods.

在算法中，把决定代数曲面测地线的微分方程组离散为一个非线性方程组，然后采用迭代数值方法求解。

The finite difference is used to approximate differential operation; the reflectance map equation described by the first order nonlinear differential equation is transformed into an algebraic equation about the unknown surface heights, and then the objective equation is constructed by the reflectance map equation and gradient information of image. Moreover, the Newton iterative algorithm is utilized to obtain the numerical solution and 3D shape of the surface.

采用有限差分近似微分运算，将一阶非线性微分方程所描述的反射图方程转化为关于未知表面高度的代数方程，再由反射图方程和图像梯度信息构造目标方程，进而用Newton迭代算法求出该方程的数值解，得到表面三维形状。

A frame to construct a blending surface among quadrics with the algebraic tensor-product B-spline surfaces was presented. A C^1 continuous algebraic spline surface was obtained that very smoothly joined the given quadrics.

给出了一种应用代数张量积B样条曲面构造blending曲面的框架并详细讨论了二次代数曲面间blending曲面的构造方法。

If the surface isrepresented by an implicit algebraic equation,the mapping can be constructed bythe theory of parametrization of algebraic surfaces;If the surface is represented byan parametric equation,the parameter values on the parameter plane can be solvedby numerical method or Grobner Basis method.

若曲面由代数隐式方程给出，可通过代数曲面参数化理论构造映射；若曲面由参数方程给出，可通过数值方法或Grobner基方法求解参数型值点。

Take the method of "subarea" and "conjunction" to segment the whole request model to three parts. Making use of boundary continuousness between medium and lining structure at stress and displacement, construct a wave function that can satisfy the stress boundary condition at horizontal surface by the scattering of SH-waves in circular part. And then, availing of the wave function, conjoin the circular part into the semi-circular hollow space at common boundary. The problem can be reduced to solve the question that can only meet the condition of "conjunction". Finally, the solution of the problem can be summarized to a series of algebraic equations and solved numerically by truncating the finite terms of the infinite algebraic equations.

采用"分区"与"契合"的方法，将整个求解区域分割成三部分，利用介质与衬砌结构在边界上的应力、位移的连续性，构造一个可以自动满足水平界面上应力边界条件的圆域对SH波散射的波函数；再利用这一波函数将圆域与半圆形凹陷半空间的"公共边界"进行"契合"，将问题简化成对一个只需满足'契合'边界条件的散射问题的求解；最终归结为对一组无穷代数方程组的求解问题，利用截断有限项的方法对其进行计算。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。