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关于点向式方程的改进意见
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作者 陈国正 《数学通报》 北大核心 2003年第4期44-44,共1页
陈国正老师《关于点向式方程的改进意见》一文是对进行改革的新教材的认真钻研 ,这种精神值得鼓励 .国家规划教材《数学 (基础版 )第二册》(高教社出版 )对于直线的点向式方程的推导 ,只需要用到向量的加法和数量乘法两种运算 ,因此所... 陈国正老师《关于点向式方程的改进意见》一文是对进行改革的新教材的认真钻研 ,这种精神值得鼓励 .国家规划教材《数学 (基础版 )第二册》(高教社出版 )对于直线的点向式方程的推导 ,只需要用到向量的加法和数量乘法两种运算 ,因此所得的点向式方程不仅对于直角坐标系成立 ,而且对于仿射坐标系也成立 .如果采用向量的积来推导 ,由于向量的内积在直角坐标系中才有简洁的计算公式 ,因此所得到的直线方程只对于直角坐标系成立 .此外 ,用内积来推导 ,计算比较繁 .至于新教材在推导直线的点向式方程中 ,“约定当式中某一个分式的分母为零时就表示分子也为零” ,这种约定的合理性 ,可以参看本期发表的《高中和中等职业学校数学教学内容体系的一些改革》 展开更多
关键词 点向式方程 中等职业教育 教材 直线问题 方向向量 《数学(基础版)》
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例说空间解析几何教学中的两个题目 被引量:1
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作者 耿红梅 《科技资讯》 2009年第24期206-206,共1页
本文简要介绍了在高职数学教学中的两个题目并整理给出了多种解法:化空间直线的一般式方程为直线的点向式方程和参数式方程,整理了三种解法;求通过某个已知点和已知直线的平面方程,给出两种解法,以便读者加深对此类题目的理解。
关键词 空间直线 一般式 点向式 平面方程 法式
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NOTE ON FORMULATION OF GEOMETRIC PROPERTIES OF A POLYNOMIAL SYSTEM
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作者 郦志新 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2002年第2期203-207,共5页
This note shows that when studying geometric pro perties, a polynomial system is defined as a line field on a projective space such that its singular set has co dimension at least 2. By this definition, the concept ... This note shows that when studying geometric pro perties, a polynomial system is defined as a line field on a projective space such that its singular set has co dimension at least 2. By this definition, the concept of the degree of a polynomial system does not coincide with the usual one. The usual degenerate polynomial system of degree n+1 should be regarded as a system of degree n . Note that the definition is independent coordinate system. And, by this definition, some geometric properties concerning polynomial vector fields turn out to be evident. 展开更多
关键词 polynomial vector fields line fields geome tric properties
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关于欧氏空间R^n中若干直线方程
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作者 席小忠 《宜春师专学报》 1998年第5期57-60,共4页
给出了欧氏空间 R^n 中直线点向式和一般式两种方程,讨论了直线与直线之间、直线与 n-1维超平面之间的关系.
关键词 直线方程 点向式 平行 垂直 相交 欧氏空间
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Regenerative Strategy for Sum-rate Enhancement in Bi-directional Three-node Cooperation
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作者 胡宁 《High Technology Letters》 EI CAS 2009年第2期151-154,共4页
In bi-directional three-node cooperation, one regenerative strategy with network coding and power optimization is proposed for system sum-rate under a total energy constraint. In this paper, the network coding and pow... In bi-directional three-node cooperation, one regenerative strategy with network coding and power optimization is proposed for system sum-rate under a total energy constraint. In this paper, the network coding and power optimization are applied to improve system sum-rate. But max-rain optimization problem in power allocation is a NP-hard problem. In high Signal-to-Noise Ratio regime, this NP-hard problem is transformed into constrained polynomial optimization problem, which can be computed in polynomial time. Although it is a suboptimal solution, numerical simulations show that this strategy enhances the system sum-rate up to 45% as compared to a traditional four-phase strategy, and up to 13% as compared to the three-phase strategy without power optimization. 展开更多
关键词 bi-directional cooperation network coding power optimization regenerative strategy max-min optimization
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An invariant interest point detector under image affine transformation
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作者 林睿 黄海波 +1 位作者 孙荣川 孙立宁 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第3期914-921,共8页
For vision-based mobile robot navigation, images of the same scene may undergo a general affine transformation in the case of significant viewpoint changes. So, a novel method for detecting affine invariant interest p... For vision-based mobile robot navigation, images of the same scene may undergo a general affine transformation in the case of significant viewpoint changes. So, a novel method for detecting affine invariant interest points is proposed to obtain the invariant local features, which is coined polynomial local orientation tensor(PLOT). The new detector is based on image local orientation tensor that is constructed from the polynomial expansion of image signal. Firstly, the properties of local orientation tensor of PLOT are analyzed, and a suitable tuning parameter of local orientation tensor is chosen so as to extract invariant features. The initial interest points are detected by local maxima search for the smaller eigenvalues of the orientation tensor. Then, an iterative procedure is used to allow the initial interest points to converge to affine invariant interest points and regions. The performances of this detector are evaluated on the repeatability criteria and recall versus 1-precision graphs, and then are compared with other existing approaches. Experimental results for PLOT show strong performance under affine transformation in the real-world conditions. 展开更多
关键词 local orientation tensor interest point detector affine invariant image polynomial expansion
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