193 research outputs found

    Про один підхід до ідентифікації особи за контуром профілю носа

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    У статті розглядається підхід для ідентифікації особи за контуром профілю носа. Для знаходження простору ознак пропонується використовувати апроксимацію за допомогою B-сплайнів. Алгоритмічна реалізація підходу використовує моделювання структури бази даних у вигляді n- вимірного куба.В статье рассматривается подход для идентификации личности по контуру носа. Для нахождения пространства признаков предлагается использовать аппроксимацию с помощью B-сплайнов. Алгоритмическая реализация подхода использует моделирование структуры базы данных в виде n-мерного куба.An approach of human identification by the nose contour profile is researched in the paper. B-splines approximation is suggested for determining the feature space. Algorithmic implementation of the approach uses database structure in the form of n-dimensional cube

    Emission-Line Properties of z > 4 Quasars

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    We present results of a program of high signal-to-noise spectroscopy for 44 QSOs at redshifts > 4 using the MMT and Keck observatories. The quasar spectra cover 1100 -- 1700 A in the rest frame for sources spanning a luminosity range of approximately 2 orders of magnitude. Comparisons between these data and spectra of lower redshift quasars reveal a high degree of similarity, although differences are present in the profiles and the strengths of some emission features. An examination of the luminosity dependence of the emission lines reveals evidence for a weak or absent Baldwin effect among z > 4 QSOs. We compare measurements for objects in our sample with results from other high redshift surveys characterized by different selection techniques. Distributions of equivalent widths for these different ensembles are consistent with a common parent population, suggesting that our sample is not strongly biased, or in any case, subject to selection effects that are not significantly different from other surveys, including the Sloan Digital Sky Survey. Based on this comparison, we tentatively conclude that the trends identified here are representative of high z QSOs. In particular, the data bolster indications of supersolar metallicities in these luminous, high-z sources, which support scenarios that assume substantial star formation at epochs preceding or concurrent with the QSO phenomena.Comment: 26 pages (incl. 9 figures), AASTeX v5.0, to appear in The Astrophysical Journa

    Rubber Impact on 3D Textile Composites

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    A low velocity impact study of aircraft tire rubber on 3D textile-reinforced composite plates was performed experimentally and numerically. In contrast to regular unidirectional composite laminates, no delaminations occur in such a 3D textile composite. Yarn decohesions, matrix cracks and yarn ruptures have been identified as the major damage mechanisms under impact load. An increase in the number of 3D warp yarns is proposed to improve the impact damage resistance. The characteristic of a rubber impact is the high amount of elastic energy stored in the impactor during impact, which was more than 90% of the initial kinetic energy. This large geometrical deformation of the rubber during impact leads to a less localised loading of the target structure and poses great challenges for the numerical modelling. A hyperelastic Mooney-Rivlin constitutive law was used in Abaqus/Explicit based on a step-by-step validation with static rubber compression tests and low velocity impact tests on aluminium plates. Simulation models of the textile weave were developed on the meso- and macro-scale. The final correlation between impact simulation results on 3D textile-reinforced composite plates and impact test data was promising, highlighting the potential of such numerical simulation tools

    Numerical Validation of Multiphysic Imperfect Interfaces Models

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    We investigate some mathematical and numerical methods based on asymptotic expansions for the modeling of bonding interfaces in the presence of linear coupled multiphysic phenomena. After reviewing new recently proposed imperfect contact conditions (Serpilli et al., 2019), we present some numerical examples designed to show the efficiency of the proposed methodology. The examples are framed within two different multiphysic theories, piezoelectricity and thermo-mechanical coupling. The numerical investigations are based on a finite element approach generalizing to multiphysic problems the procedure developed in Dumont et al. (2018)

    Spatial spread of infectious diseases with conditional vector preferences

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    We explore the spatial spread of vector-borne infections with conditional vector preferences, meaning that vectors do not visit hosts at random. Vectors may be differentially attracted toward infected and uninfected hosts depending on whether they carry the pathogen or not. The model is expressed as a system of partial differential equations with vector diffusion. We first study the non-spatial model. We show that conditional vector preferences alone (in the absence of any epidemiological feedback on their population dynamics) may result in bistability between the disease-free equilibrium and an endemic equilibrium. A backward bifurcation may allow the disease to persist even though its basic reproductive number is less than one. Bistability can occur only if both infected and uninfected vectors prefer uninfected hosts. Back to the model with diffusion, we show that bistability in the local dynamics may generate travelling waves with either positive or negative spreading speeds, meaning that the disease either invades or retreats into space. In the monostable case, we show that the disease spreading speed depends on the preference of uninfected vectors for infected hosts, but also on the preference of infected vectors for uninfected hosts under some circumstances (when the spreading speed is not linearly determined). We discuss the implications of our results for vector-borne plant diseases, which are the main source of evidence for conditional vector preferences so far.The MODCOV19 CNRS platform, the European Agricultural Fund for Rural Development (EAFRD) within the DPP “Santé & Biodiversité” framework, the DST/NRF SARChI Chair in Mathematical Models and Methods in Biosciences and Bioengineering at the University of Pretoria, South Africa, the Conseil Régional de la Réunion (France), the Conseil Départemental de la Réunion (France), the European Agricultural Fund for Rural Development (EAFRD) and the Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), France.https://link.springer.com/journal/2852024-08-03hj2024Mathematics and Applied MathematicsNon

    A Pitfall in the Diagnosis of Unresectable Liver Metastases: Multiple Bile Duct Hamartomas (von Meyenburg Complexes)

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    Von Meyenburg complexes (VMC) are a cluster of benign liver malformations including biliary cystic lesions, with congenital fibrocollagenous stroma. This rare entity can mimick multiple secondary hepatic lesions. We report a case of a 56-year-old woman who had multiples liver lesions 12 years after operation for breast cancer. Biopsy of the hepatic lesion confirmed the diagnosis of VMC. Preoperative discovery of multiple gray-white nodular lesions scattered on the surface of the liver should not always contraindicate curative liver resection. The diagnosis of VMC should be known and confirmed with liver biopsy

    A new 3MW ECRH system at 105 GHz for WEST

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    The aim of the WEST experiments is to master long plasma pulses (1000s) and expose ITER-like tungsten wall to deposited heat fluxes up to 10 MW/m2^2. To increase the margin to reach the H-Mode and to control W-impurities in the plasma, the installation of an upgraded ECRH heating system, with a gyrotron performance of 1MW/1000s per unit, is planned in 2023. With the modifications of Tore Supra to WEST, simulations at a magnetic field B0_0∼3.7T and a central density ne0_{e0}∼6 × 1019^{19} m3^{−3} show that the optimal frequency for central absorption is 105 GHz. For this purpose, a 105 GHz/1MW gyrotron (TH1511) has been designed at KIT in 2021, based on the technological design of the 140 GHz/1.5 MW (TH1507U) gyrotron for W7-X. Currently, three units are under fabrication at THALES. In the first phase of the project, some of the previous Tore Supra Electron Cyclotron (EC) system components will be re-installed and re-used whenever possible. This paper describes the studies performed to adapt the new ECRH system to 105 GHz and the status of the modifications necessary to re-start the system with a challenging schedule

    Boosting Institute of Chemistry, Technology and Metallurgy in water biomonitoring - BIOLAWEB

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    Project "Boosting Institute of Chemistry, Technology and Metallurgy in Water Biomonitoring" (BIOLAWEB) aims to strengthen the research and innovation capacity of the Institute of Chemistry, Technology and Metallurgy, National Institute of the Republic of Serbia, University of Belgrade (UB-ICTM) in biodiversity assessment and biomonitoring. UB-ICTM researchers made a noticeable contribution to the study of biodiversity, community ecology, and conservation of water bodies in South-Eastern Europe. However, a knowledge on index development and intercalibration following the EU standards for lakes and watercourse monitoring is still lacking in this geographic region. Similarly, there is a knowledge gap in DNA-based ecological status assessment in SEE.Abstract from ExcellMater Conference 2024 (ExcellMater Conference 2024: Innovative biomaterials for novel medical devices) published in Supplementary Issue
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