Search results for "Matrix"

showing 10 items of 3205 documents

Increasing efficiency of photovoltaic systems under non-homogeneous solar irradiation using improved Dynamic Programming methods

2017

Abstract The paper presents a complete technique, based on the combination of algorithms, devoted to minimize losses and increase efficiency of Total Cross Tied (TCT) connected photovoltaic (PV) systems under non-homogeneous solar irradiation, based on irradiance equalization criterion. Irradiance equalization is achieved by changing the connections of the solar panels adaptively by a dynamic switching matrix so that total solar radiation on parallel circuits is the most equalized. In this paper, the authors introduce two algorithms. The first one is SmartChoice (SC) algorithm, which is combined with Dynamic Programming (DP) in order to create a hybrid method and obtain better results as co…

OptimizationComputer scienceRenewable Energy Sustainability and the Environment020209 energyPhotovoltaic systemEqualization (audio)Irradiance02 engineering and technologyRadiationSeries and parallel circuitsDynamic programmingSettore ING-IND/33 - Sistemi Elettrici Per L'EnergiaMatrix (mathematics)Settore ING-IND/31 - ElettrotecnicaMismatchPhotovoltaic moduleReconfiguration0202 electrical engineering electronic engineering information engineeringElectronic engineeringGeneral Materials ScienceIrradiationMaterials Science (all)
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A hierarchical architecture for increasing efficiency of large photovoltaic plants under non-homogeneous solar irradiation

2019

Abstract Under non-homogeneous solar irradiation, photovoltaic (PV) panels receive different solar irradiance, resulting in a decrease in efficiency of the PV generation system. There are a few technical options to fix this issue that goes under the name of mismatch. One of these is the reconfiguration of the PV generation system, namely changing the connections of the PV panels from the initial configuration to the optimal one. Such technique has been widely considered for small systems, due to the excessive number of required switches. In this paper, the authors propose a new method for increasing the efficiency of large PV systems under non-homogeneous solar irradiation using Series-Para…

OptimizationFabricationRenewable Energy Sustainability and the EnvironmentComputer science020209 energyPhotovoltaic systemControl reconfigurationTopology (electrical circuits)02 engineering and technology021001 nanoscience & nanotechnologySolar irradianceSettore ING-IND/33 - Sistemi Elettrici Per L'EnergiaMatrix (mathematics)Settore ING-IND/31 - ElettrotecnicaMismatchPhotovoltaic moduleReconfiguration0202 electrical engineering electronic engineering information engineeringKey (cryptography)Electronic engineeringGeneral Materials ScienceArchitecture0210 nano-technology
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Contribution à l'étude de la formation des images optiques en microscopie champ proche optique: effet de la sonde en deux dimensions

2004

This work consists in the development of a theoretical tool for the purpose to undertake numerical simulations able to take into account the coupling between the probe and the object. The first part, concerns the combination of the differential method and the algorithms T and S, to overcome numerical problems which appear in the cases where the size of system (probe - object) is more realistic. The developed global model is two-dimensional and applied in polarization TE under the normal diffraction condition. We have used the developed model to study the formation of optical image by monomodes and multimodes probes. The obtained optical images at constant height, have allowed us to study th…

Optique de champ prochePhotonic Scanning Tunnelling Microscopy ( PSTM)Near-field opticImages optiquesMéthode différentielle et Algorithmes matricielsmatrix algorithmsprobe-object couplingCouplage sonde-objetOptical imagesOptical ProbeMéthode différentielle et Algorithmes matriciels.[PHYS.PHYS] Physics [physics]/Physics [physics]differential methodMicroscope à effet Tunnel Photonique (PSTM)
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Hundreds of nuclear and plastid loci yield novel insights into orchid relationships.

2021

Pérez-Escobar, Oscar Alejandro, Dodsworth, Steven, Bogarín, Diego, Bellot, Sidonie, Balbuena, Juan A, Schley, Rowan J, Kikuchi, Izai A, Morris, Sarah K, Epitawalage, Niroshini, Cowan, Robyn, Maurin, Olivier, Zuntini, Alexandre, Arias, Tatiana, Serna-Sánchez, Alejandra, Gravendeel, Barbara, Torres Jimenez, Maria Fernanda, Nargar, Katharina, Chomicki, Guillaume, Chase, Mark W, Leitch, Ilia J, Forest, Félix, Baker, William J (2021): Hundreds of nuclear and plastid loci yield novel insights into orchid relationships. American journal of botany 108 (7): 1166-1180, DOI: http://doi.org/10.5281/zenodo.7778176

OrchidaceaeCharacter evolutionNuclear genemultilocus phylogenetic treesbiologyPhylogenetic treenuclearplastid discordancefungifood and beveragesAngiosperms353Plant ScienceBiodiversitybiology.organism_classificationGenomeDNA sequencingrecombinationNuclear- plastid discordanceincongruenceEvolutionary biologyGeneticsSupermatrixPlastidOrchidaceaeEcology Evolution Behavior and SystematicsTaxonomy
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Shed membrane vesicles and selective localization of gelatinases and MMP-9/TIMP-1 complexes.

1999

OrganellesGelatinasesTissue Inhibitor of Metalloproteinase-1ChemistryGeneral NeuroscienceBlotting WesternCell MembraneBreast NeoplasmsMatrix metalloproteinaseGeneral Biochemistry Genetics and Molecular BiologyCell biologyHistory and Philosophy of ScienceMatrix Metalloproteinase 9GelatinasesTumor Cells CulturedHumansMembrane vesicleFemaleCollagenCollagenasesProtein BindingAnnals of the New York Academy of Sciences
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Low-pressure pyrolysis of tBu2SO: synthesis and IR spectroscopic detection of HSOH.

2005

Sulfenic acid (HSOH, 1) has been synthesized in the gas-phase by low-pressure high-temperature (1150 degrees C) pyrolysis of di-tert-butyl sulfoxide (tBu(2)SO, 2) and characterized by means of matrix isolation and gas-phase IR spectroscopy. High-level coupled-cluster (CC) calculations (CCSD(T)/cc-pVTZ and CCSD(T)/cc-pVQZ) support the first identification of the gas-phase IR spectrum of 1 and enable its spectral characterization. Five of the six vibrational fundamentals of matrix-isolated 1 have been assigned, and its rotational-resolved gas-phase IR spectrum provides additional information on the O-H and S-H stretching fundamentals. Investigations of the pyrolysis reaction by mass spectrome…

Organic ChemistryIntermolecular forceAnalytical chemistryMatrix isolationInfrared spectroscopySulfoxideGeneral ChemistryMass spectrometryCatalysischemistry.chemical_compoundchemistryIntramolecular forceDensity functional theorySpectroscopyChemistry (Weinheim an der Bergstrasse, Germany)
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Correlation, hierarchies, and networks in financial markets

2010

We discuss some methods to quantitatively investigate the properties of correlation matrices. Correlation matrices play an important role in portfolio optimization and in several other quantitative descriptions of asset price dynamics in financial markets. Specifically, we discuss how to define and obtain hierarchical trees, correlation based trees and networks from a correlation matrix. The hierarchical clustering and other procedures performed on the correlation matrix to detect statistically reliable aspects of the correlation matrix are seen as filtering procedures of the correlation matrix. We also discuss a method to associate a hierarchically nested factor model to a hierarchical tre…

Organizational Behavior and Human Resource ManagementEconomics and EconometricsPhysics - Physics and SocietyCorrelation based networkKullback–Leibler divergenceStability (learning theory)FOS: Physical sciencesKullback–Leibler distancePhysics and Society (physics.soc-ph)computer.software_genreHierarchical clusteringFOS: Economics and businessCorrelationMultivariate analysis Hierarchical clustering Correlation based networks Bootstrap validation Factor models Kullback–Leibler distancePortfolio Management (q-fin.PM)Bootstrap validationQuantitative Finance - Portfolio ManagementMathematicsFactor analysisStatistical Finance (q-fin.ST)Covariance matrixMultivariate analysiQuantitative Finance - Statistical FinanceHierarchical clusteringFactor modelTree (data structure)Physics - Data Analysis Statistics and ProbabilityData miningPortfolio optimizationcomputerData Analysis Statistics and Probability (physics.data-an)
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Static output-feedback control under information structure constraints

2013

An important challenge in the static output-feedback control context is to provide an isolated gain matrix possessing a zero-nonzero structure, mainly in problems presenting information structure constraints. Although some previous works have contributed some relevant results to this issue, a fully satisfactory solution has not yet been achieved up to now. In this note, by using a Linear Matrix Inequality approach and based on previous results given in the literature, we present an e cient methodology which permits to obtain an isolated static output-feedback gain matrix having, simultaneously, a zero-nonzero structure imposed a priori. Peer Reviewed

Output feedbackAutomatic controlLMIs:Informàtica::Automàtica i control [Àrees temàtiques de la UPC]:Matemàtiques i estadística::Anàlisi numèrica::Mètodes numèrics [Àrees temàtiques de la UPC]:15 Linear and multilinear algebra; matrix theory [Classificació AMS]Information structureControl (management):15 Linear and multilinear algebra [Classificació AMS]Structure (category theory)Linear matrix inequalityContext (language use)Information structure constraintsOutput-feedback controlMatrius (Matemàtica)Control automàticMatrix (mathematics)Control and Systems EngineeringControl theoryInformation structure constraints; LMIs; Output-feedback controlmatrix theoryA priori and a posterioriElectrical and Electronic EngineeringMatrix inequalitiesMathematics
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Recent Advances in Static Output-Feedback Controller Design with Applications to Vibration Control of Large Structures

2014

Published version of an article in the journal: Modeling, Identification and Control. Also available from the publisher at: http://dx.doi.org/10.4173/mic.2014.3.4 Open Access In this paper, we present a novel two-step strategy for static output-feedback controller design. In the first step, an optimal state-feedback controller is obtained by means of a linear matrix inequality (LMI) formulation. In the second step, a transformation of the LMI variables is used to derive a suitable LMI formulation for the static output-feedback controller. This design strategy can be applied to a wide range of practical problems, including vibration control of large structures, control of oshore wind turbine…

Output feedbackEngineeringDecentralized control:Informàtica::Automàtica i control [Àrees temàtiques de la UPC]Static output-feedbackStructural Vibration ControlControl (management)Vibration control:Enginyeria civil::Materials i estructures [Àrees temàtiques de la UPC]Feedback control systemsMatrius (Matemàtica)VDP::Mathematics and natural science: 400::Mathematics: 410::Analysis: 411lcsh:QA75.5-76.95Structural vibration controlControl d'estructures (Enginyeria):93 Systems Theory; Control [Classificació AMS]Decentralized Control; Static Output-feedback; Structural Vibration Control; Control and Systems Engineering; Software; Modeling and Simulation; Computer Science Applications1707 Computer Vision and Pattern RecognitionComputer Science::Systems and ControlControl theoryControlMatrix inequalitiesController design:93 Systems Theory [Classificació AMS]business.industryComputer Science Applications1707 Computer Vision and Pattern RecognitionControl engineeringDecentralized ControlDecentralised systemComputer Science ApplicationsIdentification (information)Control and Systems EngineeringModeling and SimulationSistemes de control per retroaccióStatic Output-feedbacklcsh:Electronic computers. Computer scienceStructural control (Engineering)businessSoftwareModeling, Identification and Control: A Norwegian Research Bulletin
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Static output-feedback controller design for vehicle suspensions: an effective two-step computational approach

2014

In this study, a novel two-step methodology is applied in designing static output-feedback controllers for a class of vehicle suspension systems. Following this approach, an effective synthesis of static output-feedback controllers can be carried out by solving two consecutive linear matrix inequality optimisation problems. To illustrate the main features of the proposed design strategy, two different static output-feedback H 8 controllers are designed for a quarter-car suspension system. The first of those controllers uses the suspension deflection and the sprung mass velocity as feedback information, whereas the second one only requires the sprung mass velocity to compute the control acti…

Output feedbackEngineeringFrequency responseControl and Optimization:Informàtica::Automàtica i control [Àrees temàtiques de la UPC]Linear matrix inequalitiesVehicle suspensionsDesign strategyControl and Systems Engineering; Human-Computer Interaction; Computer Science Applications1707 Computer Vision and Pattern Recognition; Control and Optimization; Electrical and Electronic EngineeringFeedback control systemsMatrius (Matemàtica)Vehicles -- Ressorts i suspensió:93 Systems Theory; Control [Classificació AMS]Control theoryDeflection (engineering)ControlElectrical and Electronic EngineeringMatrix inequalitiesSuspension (vehicle)Controller design:93 Systems Theory [Classificació AMS]Vehicles--Springs and suspensionbusiness.industryLinear matrix inequality:Matemàtiques i estadística [Àrees temàtiques de la UPC]Control engineeringComputer Science Applications1707 Computer Vision and Pattern RecognitionVehicles -- Springs and suspensionComputer Science ApplicationsHuman-Computer InteractionControl and Systems EngineeringSistemes de control per retroaccióSprung massbusinessStatic output-feedback control
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