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Wyszukujesz frazę "curvature tensor" wg kryterium: Temat


Wyświetlanie 1-6 z 6
Tytuł:
Pseudo-Bochner curvature tensor on Hermitian manifolds
Autorzy:
Matsuo, Koji
Powiązania:
https://bibliotekanauki.pl/articles/965855.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
Hermitian manifold
Hermitian connection
pseudo-Bochner curvature tensor
(Hermitian) pseudo-curvature tensor
Opis:
Our main purpose of this paper is to introduce a natural generalization $B_H$ of the Bochner curvature tensor on a Hermitian manifold $M$ provided with the Hermitian connection. We will call $B_H$ the pseudo-Bochner curvature tensor. Firstly, we introduce a unique tensor P, called the (Hermitian) pseudo-curvature tensor, which has the same symmetries as the Riemannian curvature tensor on a Kähler manifold. By using P, we derive a necessary and sufficient condition for a Hermitian manifold to be of pointwise constant Hermitian holomorphic sectional curvature. Our pseudo-Bochner curvature tensor $B_H$ is naturally obtained from the conformal relation for the pseudo-curvature tensor P and it is conformally invariant. Moreover we show that $B_H$ is different from the Bochner conformal tensor in the sense of Tricerri and Vanhecke.
Źródło:
Colloquium Mathematicum; 1999, 80, 2; 201-209
0010-1354
Pojawia się w:
Colloquium Mathematicum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hypersurfaces with parallel affine curvature tensor R*
Autorzy:
Opozda, Barbara
Verstraelen, Leopold
Powiązania:
https://bibliotekanauki.pl/articles/1293996.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
curvature tensor
induced connection
affine normal
Opis:
In [OV] we introduced an affine curvature tensor R*. Using it we characterized some types of hypersurfaces in the affine space $ℝ^{n+1}$. In this paper we study hypersurfaces for which R* is parallel relative to the induced connection.
Źródło:
Annales Polonici Mathematici; 1999, 72, 1; 25-32
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On weakly symmetric generalized trans-sasakian manifold
Autorzy:
Das, Levejoy S.
Nivas, Ram
Agnihotri, Rupali
Powiązania:
https://bibliotekanauki.pl/articles/1912861.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
Trans-Sasakian manifold
weakly symmetric
Riemannian manifold
curvature tensor
Opis:
In this paper, we have defined the weakly symmetric generalized Trans-Sasakian manifold \(G(WS)_n\) and it has been shown that on such manifold if any two of the vector fields \(\lambda,\gamma,\tau\), defined by equation (0.3) are orthogonal to \(\xi\), then the third will also be orthogonal to \(\xi\). We have also proved that the scalar curvature \(r\) of weakly symmetric generalized Trans-Sasakian manifold \(G(WS)_n\), \((n > 2)\) satisfies the equation \(r = 2n(\alpha^2 − \beta^2)\), where \(\alpha\) and \(\beta\) are smooth function and \(\gamma\not=\tau\).
Źródło:
Commentationes Mathematicae; 2014, 54, 1
0373-8299
Pojawia się w:
Commentationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-scale curvature tensor analysis of machined surfaces
Autorzy:
Bartkowiak, T.
Brown, C.
Powiązania:
https://bibliotekanauki.pl/articles/1203966.pdf
Data publikacji:
2016
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
curvature tensor
surface metrology
multi-scale geometric characterization
machining
tensor krzywizny
metrologia powierzchni
charakterystyka geometryczna
obróbka
Opis:
This paper demonstrates the use of multi-scale curvature analysis, an areal new surface characterization technique for better understanding topographies, for analyzing surfaces created by conventional machining and grinding. Curvature, like slope and area, changes with scale of observation, or calculation, on irregular surfaces, therefore it can be used for multi-scale geometric analysis. Curvatures on a surface should be indicative of topographically dependent behavior of a surface and curvatures are, in turn, influenced by the processing and use of the surface. Curvatures have not been well characterized previously. Curvature has been used for calculations in contact mechanics and for the evaluation of cutting edges. In the current work two parts were machined and then one of them was ground. The surface topographies were measured with a scanning laser confocal microscope. Plots of curvatures as a function of position and scale are presented, and the means and standard deviations of principal curvatures are plotted as a function of scale. Statistical analyses show the relations between curvature and these two manufacturing processes at multiple scales.
Źródło:
Archives of Mechanical Technology and Materials; 2016, 36; 44-50
2450-9469
Pojawia się w:
Archives of Mechanical Technology and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extension of the one-dimensional Stoney algorithm to a two-dimensional case
Autorzy:
Gniazdowski, Zenon
Powiązania:
https://bibliotekanauki.pl/articles/91318.pdf
Data publikacji:
2019
Wydawca:
Warszawska Wyższa Szkoła Informatyki
Tematy:
Stoney formula
Stoney equation
2D Stoney algorithm
tensor of curvature
stress in a thin film
anisotropy
quadric
quadratic form
Opis:
This article presents the extension of the one-dimensional Stoney algorithm to a two-dimensional case. The proposed extension consists in modifying the method of curvature estimation. The surface profile of the wafer before deposition of the thin film and after its deposition was locally approximated by the quadric. From this quadric, a quadratic form and the first degree surface were separated. An eigenproblem was solved for the matrix of this quadratic form. From eigenvectors a new coordinate system was created in which a new formula of the quadric was found. In this new coordinate system, the two-dimensional problem of estimating thecurvaturetensorhasbeensolvedbysolvingtwoindependentone-dimensional problems of curvature estimation. Returning to the primary coordinate system, in this primary system, a solution to the two-dimensional problem was obtained. The article proposes five versions of the two-dimensional Stoney algorithm, with diverse complexity and accuracy. The recommendation for the version of the algorithm that could be practically used was also presented.
Źródło:
Zeszyty Naukowe Warszawskiej Wyższej Szkoły Informatyki; 2019, 13, 20; 41-66
1896-396X
2082-8349
Pojawia się w:
Zeszyty Naukowe Warszawskiej Wyższej Szkoły Informatyki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
No-reference quality metric for high dynamic range imaging system based on curvature analysis in tensor domain
Autorzy:
Jiang, Gangyi
Yu, Jiaowen
Yu, Mei
Song, Yang
Peng, Zongju
Chen, Fen
Powiązania:
https://bibliotekanauki.pl/articles/173642.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
high dynamic range image
no-reference quality metric
tensor domain
curvature analysis
quality-related label feature matrix
Opis:
High dynamic range imaging systems can offer a more complete representation of scene, aiming to capture all brightness information of a visible range of scene, even in extreme lighting conditions.This paper proposes a no-reference quality metric for high dynamic range image (HDRI), in which a combination of tensor decomposition and curvature analysis is used to construct an efficient featureset that is sensitive to degradation levels of patches in HDRIs. Tensor decomposition maintains the majority of color information of an HDRI, and the geometric structure information of the HDRI is then extracted by a curvature analysis. A quality-related label feature matrix is subsequently defined and obtained by using a feature set and a sparse dictionary with quality-related labels. Then, the multi-dimensional local feature set of the HDRI is determined from the quality-related label feature matrix. Finally, the local feature set and other global feature set are pooled to predict the quality of the HDRI. The prediction performance of the proposed metric is verified by three public test databases, and the experimental results indicate that both its Pearson linear correlation coefficientand Spearman rank-order correlation coefficient are better than those of other no-reference metrics.The proposed metric produces statistically better assessment results, implying a higher consistency with human visual perception.
Źródło:
Optica Applicata; 2019, 49, 4; 527-543
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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