Search results for "Visible"

Estimation de l’indice foliaire et de la biomasse du blé et des adventices par imagerie visible et machine learning : vers un nouvel indicateur non d…

2019

National audience; Cette étude propose d’estimer précocement par imagerie deux variables clés dans la gestion des cultures et dans la compétition culture-adventices : l’indice foliaire (LAI) et la biomasse aérienne sèche (BM). Une expérimentation a été conduite au champ pendant la phase végétative d’une culture de blé. Pour chaque peuplement (culture de blé, adventices), les taux de couverture du sol par la végétation (TCc, TCw) ont été déduits du traitement d’image basé sur une technique de machine learning. LAI et BM ont été mesurés de façon destructive. Puis, une calibration a été réalisée entre TC et LAI d’une part et entre TC et BM d’autre part. Ce travail pourrait, à terme, faciliter …

Showing the Invisible: The Economic Cycle of Stone Tools

2023

This contribution takes place in a broader theme, that of “the invisible economy of recyclable materials”. It aims to illustrate the phenomena of recovery of materials from lithic tools and their consequences. The classification of tools by material, although classic, is not relevant from a technical point of view. The material of a tool, in particular its mechanical properties, is to be taken into consideration in its technical analysis, but it cannot constitute a determining criterion in a classification system. Function should come first, as most functional categories use multiple materials. The most striking example, if one can say so, is that of the striking supports, where one finds, …

L'extension de la clause compromissoire dans les conventions indivisibles

2003

International audience; (Paris, 1re ch. C, 13 févr. 2003, Sidy Diallo c/ G. Andrieu, inédit)

Le poids de l’(in)visibilité

2022

Target 5G visible light positioning signal subcarrier extraction method using particle swarm optimization algorithm

2021

International audience; With the explosive growth of demand for Internet of Things (IoT) applications and the increasing dependence of users on wireless connections, indoor location based service(LBS) under 5G-Public-Private Partnership (5G-PPP) using cases have received more attention and get rapid development. Thanks to the safty, security and customization of 5G network pointed by 5G forum white paper, indoor positioning systems using unified 5G New Radio (NR) signals have become the focus of the next generation of visible light positioning (VLP) systems. In 5G New Radio(NR) frame, totally 192 subcarriers are used to carry positioning reference signal(PRS). In order to improve the positi…

On improving the accuracy of Visible Light Positioning system using deep autoencoder

2020

International audience; DC-biased optical Orthogonal Frequency DivisionMultiplexing (DCO-OFDM)-based visible light positioning (VLP)technology along with the Received Signal Strength(RSS) po-sitioning algorithm is widely used to achieve centimeter levelpositioning accuracy for incoming 5G era, especially indoorenvironment. However, the DCO-OFDM has the peak-to-averagepower ratio (PAPR) issue which imposes the nonlinear distortionand it will directly affect the positioning accuracy in the VLPsystem. The PAPR reduction scheme is urgently needed. There-fore, in this paper, the impact of PAPR reduction scheme onpositioning accuracy is investigated. The positioning accuracywith and without the s…

SmartSpectra: Applying multispectral imaging to industrial environments

2005

SmartSpectra is a smart multispectral system for industrial, environmental, and commercial applications where the use of spectral information beyond the visible range is needed. The SmartSpectra system provides six spectral bands in the range 400-1000nm. The bands are configurable in terms of central wavelength and bandwidth by using electronic tunable filters. SmartSpectra consists of a multispectral sensor and the software that controls the system and simplifies the acquisition process. A first prototype called Autonomous Tunable Filter System is already available. This paper describes the SmartSpectra system, demonstrates its performance in the estimation of chlorophyll in plant leaves, …

Visible Light-Induced Sulfonylation/Arylation of Styrenes in a Double Radical Three-Component Photoredox Reaction

2019

Simultaneous sulfonylation/arylation of styrene derivatives is achieved in a photoredox-catalyzed three-component reaction using visible light. A broad variety of difunctionalized products is accessible in mostly excellent yields and high diastereoselectivity. The developed reaction is scalable and suitable for the modification of styrene-functionalized biomolecules. Mechanistic investigations suggest the transformation to be operating through a designed sequence of radical formation and radical combination.

2018

A visible light-promoted protocol for the redox-neutral coupling of N-hydroxyphthalimide esters with different N-heterocyclic compounds is described. The reaction proceeds through an alkyl radical intermediate generated by reductive decarboxylation of N-hydroxyphthalimide esters. In contrast to the original Minisci protocol, polyalkylation can largely be avoided. Mechanistic investigations revealed a radical chain mechanism which in some cases can proceed even if no photocatalyst is added. This valuable and functional group-tolerant reaction produces substituted heterocycles in moderate to excellent yield. The use of inexpensive starting materials and LEDs as the light source are key featur…

Equilibria involved in the diorganotin(IV) and triorganotin(IV) phosphomycin interaction in aqueous solution

2007

Four new diorganotin(IV), (R = Me, Bu), and triorganotin(IV), (R = Me, Ph), derivatives of the phosphomycin disodium salt antibiotic[(1R,2S)-1,2-epoxypropylphosphonate]Na2 have been synthesized and their solid state configuration studied by X-ray crystallography, FT-IR, Mossbauer, UV–Vis spectroscopies. The X-ray diffraction investigation, performed on the bis[trimethyltin(IV)]- phosphomycin, showed that the coordination geometry at all the Sn atoms is trigonal bipyramidal. The structure of the complex forms an unusual polymeric zig-zag planar network. The FT-IR and the 119Sn Mo¨ssbauer studies supported the formation of trigonal bipyramidal (Tbp) molecular structures, both in the diorganot…