共查询到20条相似文献，搜索用时 15 毫秒
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在芭蕾舞中,"旋转"占有重要的位置.它是舞蹈语言中令人肯定的组成部分,不同速度的"旋转"可以表达舞者的不同情感,因此"旋转"的训练在芭蕾基训中起着至关重要的作用. 相似文献
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江河 《河北软件职业技术学院学报》2011,13(1):37-38
在网络信息时代,将有限的时间投入到查找无限的信息资源中是不可取的,如何使用户在信息大潮中搜索到有用的信息,已成为研究的重要课题。主动式网页搜索技术成为当今信息系统中重要的研究方向。基于本体的自动网页检索系统会主动提供关键词判断比对,进而提升网页搜集的精确度。 相似文献
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The Bézier curve is one of the most commonly used parametric curves in CAGD and Computer Graphics and has many portant problem, and is also an important research issue in CAD/CAM and NC technology fields. This work investigates the curves to satisfy the given constraints and modify the shape of the curves optimally. Practical examples are also given. 相似文献
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The reproduction characteristics of 343 sows in six different breeding groups were analyzed to estimate the crossbreeding parameters. The results indicated that the ovulation rate and the weights of uterus and ovary are mainly determined by the additive genetic effects while the nonadditive genetic effects play an important role in embryonal traits and litter performance. The heterosis effects in the first litter are larger than those in the second litter because of heterosis x environment interaction. The results also showed the existence of a highly significant maternal heterosis effect on the fertility traits of sows. 相似文献
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This paper presents a quadratic programming method for optimal multi-degree reduction of Bézier curves with G1-continuity. The L2 and l2 measures of distances between the two curves are used as the objective functions. The two additional parameters, available from the coincidence of the oriented tangents, are constrained to be positive so as to satisfy the solvability condition. Finally, degree reduction is changed to solve a quadratic problem of two parameters with linear constraints. Applica 相似文献
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This paper presents a basis for the space of hyperbolic polynomials Γm=span{ 1, sht, cht, sh2t, ch2t, ..., shmt, chmt} on the interval [0,α] from an extended Tchebyshev system, which is analogous to the Bernstein basis for the space of polynomial used as a kind of well-known tool for free-form curves and surfaces in Computer Aided Geometry Design. Then from this basis, we rameter variable t to arbitrary close interval [r, s] (r＜s). 相似文献
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In this paper,a G1, C1, C2 PH-spline is employed as an approximation for a given Bézier curve within error bound and further renders offset which can be regarded as an approximate offset to the Bézier curve. The errors between PH-spline and the Bézier curve, the offset to PH-spline and the offset to the given Bézier curve are also estimated. A new algorithm for constructing offset to the Bézier curve is proposed. 相似文献
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葛莉 《实验室研究与探索》2014,(11):136-140
目前的本体结构,多使用多个组织公用一套访问控制策略,这不利于组织间的机密性保护,降低了系统的安全性。为了实现协同环境下网络访问的互操作性,即在协同网络下实现不同安全策略的代理间的语义兼容,需要使用本体为用户和应用程序提供一个共享的知识与领域。本文在P2P网路中使用OrBAC模型并对该结构进行了研究,提出了一种改进的本体结构,通过O2O使用组织的虚拟原则来扩展OrBAC,使多个组织可同时定义自己的访问控制策略,即每个P2P网络通信参与者都可以在不同的安全策略下建立起语义间的兼容性,从而在保障系统安全性的同时降低系统访问控制的复杂程度。并使用软件Protégé对结果进行了验证。 相似文献
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Bézier curves with shape parameter 总被引：3，自引：0，他引：3
INTRODUCTION The Bézier curves and surfaces form a basic toofor constructing free form curves and surfaces. Manbasis-like Bézier basis are presented. Said (1989) anGoodman and Said (1991) constructed the Ball basisMainar et al.(2001) found some bases for the space{1, t, cost, sint, cos2t, sin2t}, {1, t, t2, cost, sint}, an{1, t, cost, sint, tcost, tsint}. Chen and Wang (2003gave the C-Bézier basis in the space {1, t, t2, …, tn?2sint, cost}. Wang and Wang (2004) put forwarUniform… 相似文献
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张萌 《读与写:教育教学刊》2009,6(7)
本文通过比较专业法语教学和专业性法语教学之间的特点,表明了两者之间既有交叉,又有分别.同时,还指明两者之间的最大分别在于"供与求"之间的关系. 相似文献
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By using some elementary inequalities, authors in this paper makes further improvement for estimating the heights of Bézier curve and rational Bézier curve. And the termination criterion for subdivision of the rational Bézier curve is also improved. The conclusion of the extreme value problem is thus further confirmed. 相似文献
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Least-squares function-valued Padé-type approximation and its application in solving integral equations 总被引：1，自引：0，他引：1
To solve the Fredholm integral equations of the second kind,a new notion of the least-squares orthogonal polyno-mials of function-valued Padé-type approximation is introduced.On the basis of the error formula,the least-squares function-valued Padé-type approximation is constructed.Their existence and uniqueness are studied.A recursive computation formula of the least-squares function-valued Padé-type approximation is given.In the end,an example is given to show that the method is effiective and stable. 相似文献
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Applying homogeneous coordinates, we extend a newly appeared algorithm of best constrained multi-degree reduccomponent in homogeneous coordinates. Compared with the two traditional algorithms of "cancelling the best linear common divisor" and "shifted Chebyshev polynomial", the two new algorithms presented here using reparameterization have advantages of simplicity and fast computing, being able to preserve high degrees continuity at the end points of the curves, do multi-degree reduction at one time, and have good approximating effect. 相似文献
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Ball曲线在多项式空间中得到了广泛的研究,而且在CAD系统中也有着广泛的应用。在C-Bézier基的基础上构造的一组新的基称为C-Ball基,用这组基定义的曲线称为C-Ball曲线。讨论了三角混合多项式空间中的C-Ball基和C-Ball曲线,该曲线继承了Bézier曲线的良好的几何性质,在曲线的升降阶上比Bézier曲线更加方便,且可以通过形状参数对曲线进行形状控制。 相似文献
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Border crossing is a metaphoric term in sociolinguistics referring to a blurring of English use across different domains of social discourses.This article shows how border crossing in English job-seeking discourse is manifested in a real-life English creative résumé,and how this phenomenon brings about two related consequences,informalization and marketization,through critically analyzing the informal and promotional features of the résumé.It then reaches the conclusion that such border crossing phenomenon reflects a voice by the young in reconstructing their self-identities in job-seeking discourse in post-industrialized,post-modern western societies. 相似文献
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A novel reconstruction method from contours lines is provided. First, we use a simple method to get rid of redundant points
on every contour, then we interpolate them by using cubic Bézier spline curve. For corresponding points of different contours,
we interpolate them by the cubic Bézier spline curve too, so the whole surface can be reconstructed by the bi-cubic Bézier
spline surface. The reconstructed surface is smooth because every Bézier surface is patched with G2 continuity, the reconstruction speed is fast because we can use the forward elimination and backward substitution method
to solve the system of tridiagonal equations. We give some reconstruction examples at the end of this paper. Experiments showed
that our method is applicable and effective.
Project supported by the National Natural Science Foundation of China (Nos. 60373070 and 60573147), Postdoctor Foundation
of Shanghai (No. 05R214129), and Zhejiang Education Foundation of China (No. 20050786) 相似文献
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