共查询到20条相似文献,搜索用时 156 毫秒
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本阐述了逐差法弥补算术平均法处理数据的不足,指出逐差法配合作图法组织教学更直观更形象,用逐差法能获得近似最佳直线方程。 相似文献
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为了解决光流跟踪法定位精度不足、误差累积和特征点匹配法耗时久的问题,设计了一种将随机抽样一致性(random sample consensus,RANSAC)光流跟踪法和改进的特征点匹配法结合的视觉里程计。利用RANSAC光流跟踪法对关键帧之间的小规模运动进行估计,RANSAC算法对光流跟踪的误匹配点进行剔除,大大降低了光流跟踪法存在的误匹配;而关键帧之间的运动估计则利用改进的特征点匹配法,以修正光流跟踪法的估计误差;最后利用卡尔曼滤波将RANSAC光流跟踪法和改进的特征点匹配法进行融合。实验结果表明:该文的算法能够克服光流跟踪法精度不足、误差累积的问题,将平均相对误差由15.5%提升到了2.6%;同时也能在一定程度上提高特征点匹配法的速度,将特征点匹配法的平均耗费时间由37.28 ms提升到了21.07 ms。 相似文献
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测定含重原子晶体的结构,通常都利用Patterson法或以其为基础的重原子法、同晶型法、反常散射法等。此类方法往往会出现多解的情况。作者之一在1965年提出了用直接法消除多解问题的方法。多年来国际上在这方面也一直有类似的探讨。这类方法不仅在分析小分子晶体时有其特点,而且其进一步发展将有助于扩大直接法在生物大分子晶体结构分析中应用的领域,为提高生物大分子晶体结构分析的技术水平作出贡献。作者之一在文献[7]中已用实例说明了此类方法在中心对称情况下的应用。本文则提供非中心对称情况下的成功例子。虽然本例只处理了含重原子晶体Patterson函数的双解问题,但所用手段同样适用于处理同晶型法和反常散射法的双解。 相似文献
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应用直接法测定晶体结构,通常多半采用记号附加法与多解记号附加法进行。在相角测定中,起始套反射的确定成为测定结构成功与否的关键。目前多半采用收敛图方法确定起始套反射。本文则利用衍射指标的相关关系,提出确定起始套反射的优化选择方法,并用一个已知结构例进行了验证。
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本文利用Gear方法计算了"异形环流器极向场三级电源"中一类Stiff方程组。文中详细叙述了Gear方法的用法及自动调整步长和自动变阶问题,并与单步方法进行了比较,结果表明Gear方法比单步方法省机时。 相似文献
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介绍一种自制的磁各向异性测量装置,该装置结构简单,造价低廉,在测量过程中显示工作原理清楚直观,使用磁性薄膜中小颗粒作为样品,测量结果稳定可靠,适合学生实验使用。 相似文献
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用改进的耦合型Level Set方法计算一维双介质可压缩流动 总被引:2,自引:1,他引:1
用带有虚拟流体(Ghost Fluid)修正的Level Set方法计算了一维可压缩双介质流动,把描述流动的Euler方程和描述流体界面运动的Level Set方程耦合起来,得到一个整体的守恒律系统,应用高分辨率差分格式求解;为了解决流体界面附近的数值跳动问题,在界面附近引入了虚拟流体方法的Isobaric修正,并给出了算例. 相似文献
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ZHAO JING-LUN MAO SU-YIN MA JI-HU HAN ZONG-LAI GU YI-DONG DONG YU-JU DAI YI-FANG 《中国物理C(英文版)》1979,3(2):210-215
Using a“preselection-register-operation for reselection”program,a selection systemof the Yunan big cloud chamber set used for cosmic ray reseach is projected andconstructed.A small on-line digital computation technigue is applied to the momentumselector of the system,and a special computation element is designed.According tothe deflection angle and momentum of a charged particle passing through the magniticfield,computation and logieal judgment can be done immediately for the track signal registered before. 相似文献
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T. POTHISIRIK.D. HJELMSTAD 《Journal of sound and vibration》2002,257(1):89-106
Algorithms that estimate structural parameters from modal response using least-squares minimization of force or displacement residuals generally do not have unique solutions when the data are spatially sparse. The number and character of the multiple solutions depend upon the physical features of the structure and the locations of the response measurements. It has been observed that both the number of solutions and the sensitivity of the parameter estimates to measurement noise is greatly influenced by the choice of measurement locations. In this paper, we present a heuristic method to select a near-optimal subset of measurement locations starting from a particular set of measurements, by minimizing the sensitivity of the parameter estimates with respect to observed response. The statistical properties of solution clusters generated from a Monte Carlo samples of noisy data are used to determine the best candidate measurement to be dropped from the current set. The process is repeated until solution sensitivity cannot be significantly reduced. We also show that the laborious Monte Carlo computations can be avoided in certain cases by using a direct computation of sensitivity estimates. A numerical example is provided to illustrate the method and to examine the performance of the proposed algorithm. 相似文献
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The finite element method has been applied to the analysis of acoustic problems with several natural frequencies and mode shapes. First, a recovery-based error estimation is performed following the well-known procedures of structural problems. Then, an h -adaptive refinement strategy is proposed that leads to a finite element mesh with the minimum number of elements and with a specified error for each of the natural frequencies included in the analysis. The procedure provides a useful numerical tool, since the computational requirements are reduced. In addition, results obtained by means of the minimum element size procedure are shown for comparison purposes. The similarity of the meshes given by the two methods is justified on the basis of the equations that lead to the element size of the mesh. The procedure has been applied to some numerical examples to illustrate its validity. 相似文献