Search results for "Acquis"
showing 10 items of 876 documents
Towards automated diffraction tomography: Part I—Data acquisition
2007
Abstract The ultimate aim of electron diffraction data collection for structure analysis is to sample the reciprocal space as accurately as possible to obtain a high-quality data set for crystal structure determination. Besides a more precise lattice parameter determination, fine sampling is expected to deliver superior data on reflection intensities, which is crucial for subsequent structure analysis. Traditionally, three-dimensional (3D) diffraction data are collected by manually tilting a crystal around a selected crystallographic axis and recording a set of diffraction patterns (a tilt series) at various crystallographic zones. In a second step, diffraction data from these zones are com…
Structure solution of zeolites by automated electron diffraction tomography - Impact and treatment of preferential orientation
2014
Abstract In this paper the reliability of structure solution of nano-crystalline porous compounds with preferred orientation based on automated electron diffraction tomography (ADT) is discussed. It will be shown that the limitations of the data acquisition geometry can be overcome by completing the missing diffraction data with additional diffraction information. Apart from different ways of sample preparation, data merging with either additional ADT data sets or intensities derived from X-ray powder diffraction comprise an effective way to improve the accuracy of the structure solution.
Physics, Techniques and Review of Neuroradiological Applications of Diffusion Kurtosis Imaging (DKI)
2016
In recent years many papers about diagnostic applications of diffusion tensor imaging (DTI) have been published. This is because DTI allows to evaluate in vivo and in a non-invasive way the process of diffusion of water molecules in biological tissues. However, the simplified description of the diffusion process assumed in DTI does not permit to completely map the complex underlying cellular components and structures, which hinder and restrict the diffusion of water molecules. These limitations can be partially overcome by means of diffusion kurtosis imaging (DKI). The aim of this paper is the description of the theory of DKI, a new topic of growing interest in radiology. DKI is a higher or…
The ATLAS Level-1 Calorimeter Trigger
2008
The ATLAS Level-1 Calorimeter Trigger uses reduced-granularity information from all the ATLAS calorimeters to search for high transverse-energy electrons, photons, tau leptons and jets, as well as high missing and total transverse energy. The calorimeter trigger electronics has a fixed latency of about 1 microsecond, using programmable custom-built digital electronics. This paper describes the Calorimeter Trigger hardware, as installed in the ATLAS electronics cavern.
Digital filtering and analysis for a semiconductor X-ray detector data acquisition
2007
Abstract Pile-up distortion is a major drawback in X-ray spectroscopy at high count rate. Pulse width narrowing with shaping techniques can lead to the reduction of the pile-up distortion, but a low shaping time reduces the noise filtration and leads to a poor energy resolution. Thus, only a best compromise solution between the pile-up and the noise requirements is achievable. The hardware manipulation needed to adjust the parameters of the traditional electronic shaping amplifiers makes it uneasy to tests various settings in different conditions. Digital techniques can help to overcome such difficulties. A digital signal processing and analysis system for X-ray spectroscopy is described in…
Muon identification with the ATLAS Tile Calorimeter Read-Out Driver for Level-2 trigger purposes
2008
The Hadronic Tile Calorimeter (TileCal) at the ATLAS experiment is a detector made out of iron as passive medium and plastic scintillating tiles as active medium. The light produced by the particles is converted to electrical signals which are digitized in the front-end electronics and sent to the back-end system. The main element of the back-end electronics are the VME 9U Read-Out Driver (ROD) boards, responsible of data management, processing and transmission. A total of 32 ROD boards, placed in the data acquisition chain between Level-1 and Level-2 trigger, are needed to read out the whole calorimeter. They are equipped with fixed-point Digital Signal Processors (DSPs) that apply online …
Discrete wavelet transform based multispectral filter array demosaicking
2013
International audience; The idea of colour filter array may be adapted to multi-spectral image acquisition by integrating more filter types into the array, and developing associated demosaicking algorithms. Several methods employing discrete wavelet transform (DWT) have been proposed for CFA demosaicking. In this work, we put forward an extended use of DWT for mul-tispectral filter array demosaicking. The extension seemed straightforward, however we observed striking results. This work contributes to better understanding of the issue by demonstrating that spectral correlation and spatial resolution of the images exerts a crucial influence on the performance of DWT based demosaicking.
Aider les étudiants par un module de mise à niveau des acquis disciplinaires : Un effet sur les performances aux examens des participants sélectionné…
2013
Document de travail du CIPE; Partant d'un questionnement sur les effets d'un dispositif de remise à niveau disciplinaire sur la réussite aux examens des étudiants entrants à l'université dans le cadre du Plan Réussite en Licence à l'université de Bourgogne, cet article montre l'existence d'effets différents selon le bagage scolaire des étudiants et il souligne les impacts d'un tel programme sur la persévérance dans les études. Les résultats sur la participation réinterrogent sur les processus de sélection des étudiants choisis par l'équipe pédagogique pour suivre ce programme.
Literacy and literacy practices: Plurilingual connected migrants and emerging literacy
2021
Abstract Recent migration towards Europe is characterized by the massive presence of adults whose educational paths have been interrupted and who are thus developing literacy for the first time in a new language. A literacy test elaborated at the University of Palermo, Italy, showed that, on a sample of 774 migrants, about 30 percent could not read and/or write short words. This test assessed the learners’ abilities to read and write, whether in the Roman alphabet or in other writing systems, and whether in Italian or in other languages of learners’ repertoires. These learners with emergent literacy mostly came from sub-Saharan Africa, an area characterized by diverse forms of multilinguali…
Segment duration in Finnish as imitated by Russians
2014
The paper reports findings of a study in which Russian speakers without any prior knowledge of Finnish imitated utterances in that language, and, in particular, how they succeeded in imitating segmental duration. The data was analysed using acoustic measurements of segment duration as well as auditory analysis by four judges. The results show that Russian speakers faced difficulties in imitating some aspects of the complicated Finnish quantity system. On the other hand, many of the imitated words were judged as comprehensible. Index Terms: duration, length, Finnish, imitation, language learning