查询词典 concave curve

To some extent, using a plane curve to approximate an offset curve of the plane Bézier curve is restricted.

摘要用一条平面曲线来逼近平面Bézier曲线的等距曲线具有一定的局限性。

This paper first analyses and summarizes the ststus quo and evolution trend of encryption, some common used cryptograph are introduced, including the algorithms used in symmetric cryptosystem and asymmetirc cryptosystem. We describe the theory of each algorithms and compare the elliptic curve cryptosystem with the other two asymmetric cryptosystems to show the advantages of this algorithm. Second, the principle of ECC is discussed, including the math foundation of ECC, basic conception of elliptic curves, constructiong idea of ECC, operation on the elliptic curve and so on. Third, the current attacks of ECC were analyzed deeply, and an algorithm based on limited prime number field was constructed. We analyzed its realizability in theory, and implement it by using certain function of MIRACL software package. Latter half in this paper, the implementation model of a simple elliptic curve encryption system which based on GF has been introduced. The paper also put a deep analysis on the algorithm of point addition and point multiplication.

本文首先对密码技术的发展现状及其发展趋势进行了分析和综述，详细的介绍了私钥密码系统和公钥密码系统的发展，说明各种算法的原理和优缺点，并给出了一些典型的密码体制的简要分析，重点将椭圆曲线算法与其它几种公钥密码算法比较，说明椭圆曲线算法的优势；其次，探讨了椭圆曲线密码体制的原理，包括椭圆曲线密码的数学基础、基本概念、椭圆曲线密码体制的构造思想等问题；第三作者对椭圆曲线的攻击现状作了详细的分析，针对所使用的大素数域F_p，设计了素数域上安全椭圆曲线产生的算法，从理论上做了可实施性分析，从软件上做了具体实现；在本文的后半部分，提出了一个简单的基于有限素数域上的椭圆曲线加密方按算实现模型，并对SECES中设计的点加和点乘运算进行了深入分析。

First introduced highway alignment's definition, the significance, the developing process and the CASIO series calculator in the highway surveying computation application; Using the traverse survey computation's two basic mathematical model (azimuth calculation, coordinate calculation), compile the corresponding procedure to solve echo the wire coordinate computation; With the aid in the mathematical model which three, four and so on leveling's field operations calculate, compiles the corresponding procedure to solve the road elevation survey computation; According to relaxes the circular curve principal point and the detail coordinate computation mathematical model, based on this programs the solution to relax the circular curve coordinate principal point and the detail coordinate computation, then further develops this procedure to use to calculate the circular curve principal point and the detail coordinate computation.

首先介绍了公路线路的定义、意义、发展过程和CASIO 系列计算器在公路测量计算的应用；利用导线测量计算的两种基本数学模型，编写相应的程序以解决附和导线坐标计算；借助于三、四等水准测量的外业计算的数学模型，编写相应的程序以解决公路高程测量的计算；根据缓和圆曲线主点及细部点的坐标计算的数学模型，在此基础上编程解决缓和圆曲线坐标主点及细部点坐标的计算，然后进一步开发此程序用以计算圆曲线主点及细部点的坐标计算。

The concept of exponential transformations of rectangular Cartesiancoordinates is introduced, showing that a plane curve is more frequently expressed by a unionof four or fewer quadrantal equations defined uniquely in the respective quadrants whichthe curve covers and are therefore quadrant invariant, then the Fermat curve s with someof their geometric properties are formulated.

引入直角笛卡儿坐标幂变换的概念，说明一平面曲线是较经常地用4个或更少的象限方程的并集来表示的；这些象限方程是在曲线所在的各个象限中惟一定义的，因而是象限不变的。然后列出费马曲线的方程，并简述了费马曲线的一些几何性质

To make the quartic Bézier curve have the desired shape, the new method constructs an additional curve to describe the shape of the quartic Bézier curve.

新方法的优点是曲线须满足的连续性方程是严格三对角占优势的、曲线的不连续点在给定的数据点处、曲线是局部可调整的。

Constructing C 2 interpolation curve by quartic Bézier curve offers additional freedom degrees those can be used to adjust the shape of the curve.

用四次B？zier曲线构造C2 连续的插值曲线可提供额外的自由度，用于控制曲线的形状。新方法构造辅助曲线用于描述B？

In order to overcome these weaknesses, we use quartic B-spline structure the yield curve, which indicates the less node cubic B-spline model is better under the situation that do not use the forward rate curve, if need to make use of forward rate curve to carry on the economy analysis, the suggestion use quartic B-spline method.

为克服这些缺点，我们用四次B-样条构造收益率曲线，实证表明能克服三次B-样条曲线上述缺点。因此，在不使用远期利率曲线情况下较少节点的三次样条模型是较好选择，当需要利用远期利率曲线进行经济分析时，建议使用四次B-样条法。

With the point near the corner and the point on any edge of the corner, a piece of quartic spline curve was constructed to approximately calculate the geometrical parameter of the constructed quintic spline curve, An example of reconstructing a corner was given, and the reconstructed curve was interpolated, after which the feed rate, acceleration and jerk were analyzed respectively.

利用拐角附近点及其一条邻边上的点构建一条四次样条曲线近似计算构建的五次样条曲线几何参数。

If the method is combined with the subdivision method of curve,the rational spline curve with higher-order continuity is presented which is the approximation of offset curve.

该方法与离散算法相结合，可得到等距曲线的高阶连续的有理样条逼近曲线，最后，通过数值实例与已有方法作了比较。

Further, it is found that the limit curve is a uniform rational cubic B-spline curve or the curve's control polygon when its tension parameters tend to zero or infinity respectively.

Barsky[4 ] 将具有张力参数样条的双曲样条曲线引入CAGD ，称之为张力样条参数曲线，并证明了这种曲线是一类泛函问题的极小解。

Listen,point and check your answers.

听，指出并且检查你的答案。

Warming needle is one of effective treatment methods for knee arthralgia aggravated by cold,and it is simple,safety,so it should be developed in clinical acupuncture and moxibustion extensively.

但以本院科针灸门诊在2005年1月—2006年6月期间共收治膝痛患者100余例，经过临床的诊断后，其中施以温针治疗的48例，疗效显著，报道如下。1临床资料本组病例48