Search results for "integral"

A note on Oscar Chisini mean value definition

2012

Mainly on the basis of some notable physical examples reported in a 1929 Oscar Chisini paper, in this brief note it is exposed further possible historic-critical remarks on the definition of statistical mean which lead us towards the realm of Integral Geometry, via the Felix Klein Erlanger Programm.

SPI/INTEGRAL in-flight performance

2003

The SPI instrument has been launched on-board the INTEGRAL observatory on October 17, 2002. SPI is a spectrometer devoted to the sky observation in the 20 keV-8 MeV energy range using 19 germanium detectors. The performance of the cryogenic system is nominal and allows to cool the 19 kg of germanium down to 85 K with a comfortable margin. The energy resolution of the whole camera is 2.5 keV at 1.1 MeV. This resolution degrades with time due to particle irradiation in space. We show that the annealing process allows the recovery of the initial performance. The anticoincidence shield works as expected, with a low threshold at 75 keV, reducing the GeD background by a factor of 20. The digital …

Multidimensional Optical Sensing and Imaging Systems (MOSIS): From Macro to Micro Scales

2017

Multidimensional optical imaging systems for information processing and visualization technologies have numerous applications in fields such as manufacturing, medical sciences, entertainment, robotics, surveillance, and defense. Among different three-dimensional (3-D) imaging methods, integral imaging is a promising multiperspective sensing and display technique. Compared with other 3-D imaging techniques, integral imaging can capture a scene using an incoherent light source and generate real 3-D images for observation without any special viewing devices. This review paper describes passive multidimensional imaging systems combined with different integral imaging configurations. One example…

Exploring students’ metacognition in relation to an integral-area evaluation task

2021

Several studies have been conducted to explore students’ understanding of the integral-area relationships, however, only a few focused on students’ metacognition in relation to this topic. In this study, students’ metacognitive knowledge, skills, and experiences in relation to an integral-area evaluation task are explored using semi-structured interviews and think-aloud protocol. The results show that several students developed monitoring strategies in relation to integral-area relationships; however, they do not use these strategies when solving integral-area tasks. The findings suggest that teachers and lecturers could use monitoring strategies more often when solving mathematical questio…

A PU-integral on a compact Hausdorff space.

2002

A genomic reappraisal of symbiotic function in the aphid/Buchnera symbiosis: reduced transporter sets and variable membrane organisations.

2011

International audience; Buchnera aphidicola is an obligate symbiotic bacterium that sustains the physiology of aphids by complementing their exclusive phloem sap diet. In this study, we reappraised the transport function of different Buchnera strains, from the aphids Acyrthosiphon pisum, Schizaphis graminum, Baizongia pistaciae and Cinara cedri, using the re-annotation of their transmembrane proteins coupled with an exploration of their metabolic networks. Although metabolic analyses revealed high interdependencies between the host and the bacteria, we demonstrate here that transport in Buchnera is assured by low transporter diversity, when compared to free-living bacteria, being mostly bas…

SOME EXAMPLES RELATED TO A CLASS OF FUNCTIONALS WITHOUT GLOBAL MINIMA

2012

Abstract: In this paper, we provide six examples which show the sharpness of the assumptions of a recent deep result of Ricceri about a class of functionals without global minima.

Mejora de la captura y reproducción de imágenes integrales mediante la implementación de técnicas ópticas. Aplicaciones industriales

2022

Las imágenes tridimensionales proporcionan una visión realista del mundo que nos rodea, de ahí el interés por reproducirlas de ese modo. Esto no solo es atractivo desde una perspectiva visual y recreativa, sino que aporta un gran valor al estudio en ciencias y medicina, y al análisis y detección en los procesos industriales. De entre las técnicas que hay para capturar y reproducir imágenes 3D reales, la de imagen integral es la única capaz de hacerlo con luz natural, de forma autoestereoscópica, con paralaje continuo vertical y horizontal, en tiempo real y con tecnología de consumo. Sin embargo, y aunque se han producido grandes avances en los últimos veinte años, la técnica aún presenta ci…

Spectral multipliers and wave equation for sub-Laplacians: lower regularity bounds of Euclidean type

2018

Let $\mathscr{L}$ be a smooth second-order real differential operator in divergence form on a manifold of dimension $n$. Under a bracket-generating condition, we show that the ranges of validity of spectral multiplier estimates of Mihlin--H\"ormander type and wave propagator estimates of Miyachi--Peral type for $\mathscr{L}$ cannot be wider than the corresponding ranges for the Laplace operator on $\mathbb{R}^n$. The result applies to all sub-Laplacians on Carnot groups and more general sub-Riemannian manifolds, without restrictions on the step. The proof hinges on a Fourier integral representation for the wave propagator associated with $\mathscr{L}$ and nondegeneracy properties of the sub…

Dependence of effective properties upon regular perturbations

2022

In this survey, we present some results on the behavior of effective properties in presence of perturbations of the geometric and physical parameters. We first consider the case of a Newtonian fluid flowing at low Reynolds numbers around a periodic array of cylinders. We show the results of [43], where it is proven that the average longitudinal flow depends real analytically upon perturbations of the periodicity structure and the cross section of the cylinders. Next, we turn to the effective conductivity of a periodic two-phase composite with ideal contact at the interface. The composite is obtained by introducing a periodic set of inclusions into an infinite homogeneous matrix made of a di…