Search results for "Analisi numerica"

showing 10 items of 111 documents

Lightning-current distribution in MV grids interconnected earthing systems

2017

The paper presents first investigations results on the effects of lightning stroke on medium voltage (MV) installations' earthing systems, connected together with the metal shields of the MV distribution grid cables. The study enables to evaluate the distribution of the lightning current among interconnected earth electrodes in order to assess if the interconnection, usually done for reducing earth potential rise during an earth fault, can give place to dangerous situations far from the installation hit by the lightning stroke. Two case studies of direct lightning stroke are presented and discussed: two interconnected MV substations of the MV grid; a high voltage/medium voltage (HV/MV) stat…

EngineeringEnvironmental Engineering020209 energyEnergy Engineering and Power TechnologyShields02 engineering and technologyLightning arresterLightningIndustrial and Manufacturing EngineeringEarthing systemSettore MAT/08 - Analisi Numerica0202 electrical engineering electronic engineering information engineeringElectronic engineeringElectrical and Electronic EngineeringInterconnectionBondingEarth potential risebusiness.industryElectrical engineeringGridEarthing systemLightningSettore ING-IND/33 - Sistemi Elettrici Per L'EnergiaSettore ING-IND/31 - ElettrotecnicabusinessGlobal Earthing SystemVoltage2017 IEEE International Conference on Environment and Electrical Engineering and 2017 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe)
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On the use of SPH for Mechanical Engineering structural analyses: an elastic linear case

2011

Equilibrium equationSettore MAT/08 - Analisi Numericameshless methodsmothed particle hydrodynamicsSettore ING-IND/16 - Tecnologie E Sistemi Di Lavorazione
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On basins of attraction for a predator-prey model via meshless approximation

2016

Abstract. In this work an epidemiological predator-prey model is studied. It analyzes the spread of an infectious disease with frequency-dependent and vertical transmission within the predator population. In particular we consider social predators, i.e. they cooperate in groups to hunt. The result is a three-dimensional system in which the predator population is divided into susceptible and infected individuals. Studying the dynamical system and bifurcation diagrams, a scenario was identified in which the model shows multistability but the domain of attraction of one equilibrium point can be so small that it is almost the point itself. From a biological point of view it is important to anal…

Equilibrium pointMathematical optimizationeducation.field_of_studyPopulationSeparatrixPhase planeDynamic systemAttractionPredationSettore MAT/08 - Analisi NumericaPhysics and Astronomy (all)Applied mathematicsBasin of attractioneducationPredatorBifurcationMultistabilityMathematics
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On the Consistency Restoring in SPH

2009

Function approximationSettore MAT/08 - Analisi NumericaMeshless particle methodSmoothed Particle Hydrodynamics methodConsistency Restoring
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Diseased Social Predators

2017

Social predators benefit from cooperation in the form of increased hunting success, but may be at higher risk of disease infection due to living in groups. Here, we use mathematical modeling to investigate the impact of disease transmission on the population dynamics benefits provided by group hunting. We consider a predator-prey model with foraging facilitation that can induce strong Allee effects in the predators. We extend this model by an infectious disease spreading horizontally and vertically in the predator population. The model is a system of three nonlinear differential equations. We analyze the equilibrium points and their stability as well as one- and two-parameter bifurcations. …

Genetics and Molecular Biology (all)0106 biological sciences0301 basic medicinegenetic structuresPopulation DynamicsBasic Reproduction NumberBiochemistry01 natural sciencesCommunicable DiseasePredationMathematical modelBehavioral ecologyCooperative BehaviorPredatorMathematical ConceptGeneral Environmental ScienceAllee effectBehavioral ecology; Eco-epidemiology; Foraging facilitation; Group living; Hunting cooperation; Mathematical model; Neuroscience (all); Immunology; Mathematics (all); Biochemistry Genetics and Molecular Biology (all); 2300; Pharmacology; Agricultural and Biological Sciences (all); Computational Theory and Mathematicseducation.field_of_studyEco-epidemiologyEcologyGeneral Neuroscience010601 ecologyGroup livingComputational Theory and MathematicsFacilitationsymbolsLinear ModelGeneral Agricultural and Biological SciencesFood ChainGeneral MathematicsPopulationForagingImmunologyBehavioral ecologyBiologyCommunicable DiseasesModels BiologicalGeneral Biochemistry Genetics and Molecular Biology03 medical and health sciencessymbols.namesakeSettore MAT/08 - Analisi NumericaAnimalsMathematics (all)educationSocial BehaviorPharmacologyPopulation DynamicNeuroscience (all)Biochemistry Genetics and Molecular Biology (all)2300AnimalHunting cooperationSmall population sizeMathematical Concepts030104 developmental biologyForaging facilitationAgricultural and Biological Sciences (all)Predatory BehaviorLinear Models
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An advanced numerical model for human brain activity investigation

2012

Human brain activity numerical modelSettore ING-IND/31 - ElettrotecnicaSettore MAT/08 - Analisi Numerica
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The Poisson problem: A comparison between two approaches based on SPH method

2012

Abstract In this paper two approaches to solve the Poisson problem are presented and compared. The computational schemes are based on Smoothed Particle Hydrodynamics method which is able to perform an integral representation by means of a smoothing kernel function by involving domain particles in the discrete formulation. The first approach is derived by means of the variational formulation of the Poisson problem, while the second one is a direct differential method. Numerical examples on different domain geometries are implemented to verify and compare the proposed approaches; the computational efficiency of the developed methods is also studied.

Integral representationApplied MathematicsMathematical analysisFunction (mathematics)Domain (software engineering)Smoothed-particle hydrodynamicsSettore MAT/08 - Analisi NumericaComputational MathematicsVariational principleApplied mathematicsPoisson problem Meshless method Smoothed Particle Hydrodynamics Consistency restoring Variational principle Differential methodSmoothing kernelPoisson problemDifferential methodMathematicsApplied Mathematics and Computation
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Numerical modelling of electromagnetic sources by integral formulation

2012

Analysis of electromagnetic (EM) transients can be carried out by employing a eld approach in frequency domain, based on an appropriate integral equation. This approach is a powerful method for the analysis of EM antennas and scatterers. Recent work by the authors in modeling electromagnetic scattering in frequency domain are summarized. Thin-wire electric eld integral equation has been handled and possible application in obtaining sources localization information are discussed. Moments method (MoM) is used and time domain analysis is also carried out by discrete Fourier transform. Di erent approaches have been considered by using direct MoM formulation. Simulation results obtained both via…

Inverse problemsSettore MAT/08 - Analisi NumericaSettore ING-IND/31 - ElettrotecnicaIntegral EquationMethod of MomentIntegral Equations; Method of Moments; Inverse problems
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The smoothed particle hydrodynamics method via residual iteration

2019

Abstract In this paper we propose for the first time an iterative approach of the Smoothed Particle Hydrodynamics (SPH) method. The method is widespread in many areas of science and engineering and despite its extensive application it suffers from several drawbacks due to inaccurate approximation at boundaries and at irregular interior regions. The presented iterative process improves the accuracy of the standard method by updating the initial estimates iterating on the residuals. It is appealing preserving the matrix-free nature of the method and avoiding to modify the kernel function . Moreover the process refines the SPH estimates and it is not affected by disordered data distribution. W…

Iterative and incremental developmentComputer scienceMechanical EngineeringComputational MechanicsProcess (computing)General Physics and Astronomy010103 numerical & computational mathematicsBivariate analysisIterated residualResidual01 natural sciencesComputer Science Applications010101 applied mathematicsSmoothed-particle hydrodynamicsSettore MAT/08 - Analisi NumericaDistribution (mathematics)Smoothed particle hydrodynamicMechanics of MaterialsConvergence (routing)Test functions for optimization0101 mathematicsConvergenceAlgorithmAccuracyKernel based method
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Wavelet-like bases for thin-wire integral equations in electromagnetics

2005

AbstractIn this paper, wavelets are used in solving, by the method of moments, a modified version of the thin-wire electric field integral equation, in frequency domain. The time domain electromagnetic quantities, are obtained by using the inverse discrete fast Fourier transform. The retarded scalar electric and vector magnetic potentials are employed in order to obtain the integral formulation. The discretized model generated by applying the direct method of moments via point-matching procedure, results in a linear system with a dense matrix which have to be solved for each frequency of the Fourier spectrum of the time domain impressed source. Therefore, orthogonal wavelet-like basis trans…

Iterative methodThin-wire integral equations in electromagneticsApplied MathematicsFast Fourier transformMathematical analysisMethod of momentsWavelet transformPreconditioningElectric-field integral equationIntegral equationComputational MathematicsSettore MAT/08 - Analisi NumericaSettore ING-IND/31 - ElettrotecnicaWaveletM-band wavelet transformFrequency domainMethod of momentThin-wire integral equations in electromagneticMathematicsSparse matrix
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