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排序方式: 共有95条查询结果,搜索用时 187 毫秒
41.
Mario Bertolotti 《Contemporary Physics》2013,54(2):144-145
‘Flying Triangulation’ (FlyTri) is a recently developed principle which allows for a motion-robust optical 3D measurement of rough surfaces. It combines a simple sensor with sophisticated algorithms: a single-shot sensor acquires 2D camera images. From each camera image, a 3D profile is generated. The series of 3D profiles generated are aligned to one another by algorithms, without relying on any external tracking device. It delivers real-time feedback of the measurement process which enables an all-around measurement of objects. The principle has great potential for small-space acquisition environments, such as the measurement of the interior of a car, and motion-sensitive measurement tasks, such as the intraoral measurement of teeth. This article gives an overview of the basic ideas and applications of FlyTri. The main challenges and their solutions are discussed. Measurement examples are also given to demonstrate the potential of the measurement principle. 相似文献
42.
Alice M. Richardson Peter K. Dunn Rene Hutchins 《International Journal of Mathematical Education in Science & Technology》2013,44(7):1007-1019
Lexical ambiguity arises when a word from everyday English is used differently in a particular discipline, such as statistics. This paper reports on a project that begins by identifying tutors’ perceptions of words that are potentially lexically ambiguous to students, in two different ways. Students’ definitions of nine lexically ambiguous words are also collected at the beginning and end of a semester of introductory statistics study, in a complex design taking account of multiple tutors and multiple words in multiple contexts. Tutor perceptions and actual student difficulties at the beginning of a semester are compared. The lexical ambiguity associated with the word ‘significance’ is shown to be evident in students even after completing an introductory statistics course. 相似文献
43.
Steven Rieber 《Acta Analytica》2002,17(2):75-82
My goal is to defend the indeterminist approach to vagueness, according to which a borderline vague utterance is neither true
nor false. Indeterminism appears to contradict bivalence and the disquotational schema for truth. I agree that indeterminism
compels us to modify each of these principles. Kit Fine has defended indeterminism by claiming that ordinary ambiguous sentences
are neither true nor false when one disambiguation is true and the other is false. But even if Fine is right about sentences,
his point does not seem to generalize to utterances. What the indeterminist needs -- and what ordinary ambiguity does not
provide -- is an ambiguous utterance where what is being said is indeterminate between two different propositions. I will
show that such cases exist. These cases imply that the modifications that indeterminism makes to bivalence and the disquotational
schema are required independently of indeterminism, in fact independently of vagueness. 相似文献
44.
Azadeh Golshan Hamid Abdollahi Samira Beyramysoltan Marcel Maeder Klaus Neymeyr Robert Rajkó Mathias Sawall Romá Tauler 《Analytica chimica acta》2016
Soft modelling or multivariate curve resolution (MCR) are well-known methodologies for the analysis of multivariate data in many different application fields. Results obtained by soft modelling methods are very likely impaired by rotational and scaling ambiguities, i.e. a full range of feasible solutions can describe the data equally well while fulfilling the constraints of the system. These issues are severely limiting the applicability of these methods and therefore, they can be considered as the most challenging ones. The purpose of the current review is to describe and critically compare the available methods that attempt at determining the range of ambiguity for the case of 3-component systems. Theoretical and practical aspects are discussed, based on a collection of simulated examples containing noise-free and noisy data sets as well as an experimental example. 相似文献
45.
46.
鉴于整周模糊度的快速解算是GPS载波相位测姿的一个主要技术难题,从系统实时性、动态性要求出发,给出了一个整周模糊度的快速解算的新方法。其主要特点为:利用三角函数约束条件减少模糊度搜索范围,优选指标不受基线运动状态影响,可利用多历元动态基线数据进行平差。实验结果验证了该算法的有效性。 相似文献
47.
一种改进的LLL模糊度规约算法 总被引:1,自引:0,他引:1
整周模糊度的高效解算是GNSS高精度数据处理中的关键,基于格论进行GNSS模糊度估计时需要通过格基规约来实现最优整周模糊度向量的快速搜索。针对高维情况下常规LLL规约算法辅助整周模糊度解算存在规约耗时较长和规约性能有限的问题,引入最小列旋转QR分解技术对基向量进行预排序,采用延后尺度规约和部分尺度规约来减少规约过程中的冗余尺度规约,以改善LLL算法的执行效果。分别通过模拟和实测数据进行实验,结果表明:改进后的LLL算法可以明显降低格基规约耗时,实测环境下其规约效率相比于传统方法提高了约10倍,且能够保证较好的规约性能,从而有效提升高维模糊度的解算效率。 相似文献
48.
49.
Guji Tian 《偏微分方程(英文版)》2000,13(3):207-216
In this article we discuss the relation between Heisenberg's inequality and logarithmic Heisenberg's (entropy) inequality for ambiguity function. After building up a Heisenberg's inequality, we obtain a connection of variance with entropy by variational method. Using classical Taylor's expansion, we prove that the equality in Heisenberg's inequality holds if and only if the entropy of 2k - 1 order is equal to (2k - 1}!. 相似文献
50.
针对水下运动小目标被动探测与定位问题,提出了分段组合子阵联合处理探测方法,各探测子阵采用相互垂直结构布局,克服了单阵方位模糊及无法定位等问题。研究了分段组合子阵的宽带最小方差无畸变失真响应近场聚焦目标定位方法,实现了近程蛙人等水下小目标被动高精度定位。在此基础上,采用卡尔曼滤波算法对目标运动轨迹进行预测估计,将目标定位信息与跟踪轨迹信息进行匹配,实现高背景噪音下的运动小目标的跟踪处理。理论分析及仿真结果表明,分段子阵联合处理能有效对水下运动小目标进行定位和跟踪,海试试验进一步验证了该方法的有效性。 相似文献