Search results for "Matematica"

showing 10 items of 1637 documents

Cross-diffusion effects on stationary pattern formation in the FitzHugh-Nagumo model

2022

<p style='text-indent:20px;'>We investigate the formation of stationary patterns in the FitzHugh-Nagumo reaction-diffusion system with linear cross-diffusion terms. We focus our analysis on the effects of cross-diffusion on the Turing mechanism. Linear stability analysis indicates that positive values of the inhibitor cross-diffusion enlarge the region in the parameter space where a Turing instability is excited. A sufficiently large cross-diffusion coefficient of the inhibitor removes the requirement imposed by the classical Turing mechanism that the inhibitor must diffuse faster than the activator. In an extended region of the parameter space a new phenomenon occurs, namely the exis…

Cross-diffusion FitzHugh-Nagumo Turing instability out-of-phase patterns amplitude equationsApplied MathematicsDiscrete Mathematics and CombinatoricsSettore MAT/07 - Fisica MatematicaDiscrete and Continuous Dynamical Systems - B
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Energy and Personality: A Bridge between Physics and Psychology

2021

[EN] The objective of this paper is to present a mathematical formalism that states a bridge between physics and psychology, concretely between analytical dynamics and personality theory, in order to open new insights in this theory. In this formalism, energy plays a central role. First, the short-term personality dynamics can be measured by the General Factor of Personality (GFP) response to an arbitrary stimulus. This GFP dynamical response is modeled by a stimulus¿response model: an integro-differential equation. The bridge between physics and psychology appears when the stimulus¿response model can be formulated as a linear second order differential equation and, subsequently, reformulat…

Current (mathematics)Differential equationGeneral Mathematics050109 social psychologyStimulus-response modelErmakov–Lewis energy050105 experimental psychologyStimulus (psychology)stimulus–response modelsymbols.namesakeStimulus–response modelQA1-939Computer Science (miscellaneous)0501 psychology and cognitive sciencesEngineering (miscellaneous)Hamiltonian mechanicsPhysicsErmakov-Lewis energyPersonality dynamics05 social sciencesFísicaalgebra_number_theoryAnalytical dynamicsAction (physics)HamiltonianClassical mechanicsMinimum action principlesymbolsGeneral factor of personalityPersonalitatHamiltonian (quantum mechanics)MATEMATICA APLICADAMathematics
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Characterization of ellipsoids through an overdetermined boundary value problem of Monge–Ampère type

2014

Abstract The study of the optimal constant in an Hessian-type Sobolev inequality leads to a fully nonlinear boundary value problem, overdetermined with non-standard boundary conditions. We show that all the solutions have ellipsoidal symmetry. In the proof we use the maximum principle applied to a suitable auxiliary function in conjunction with an entropy estimate from affine curvature flow.

Curvature flowApplied MathematicsGeneral MathematicsMathematical analysisFully nonlinear equationsAuxiliary functionEllipsoidSobolev inequalityOverdetermined systemMaximum principlesMaximum principleSettore MAT/05 - Analisi MatematicaAffine curvatureOverdetermined problemsEntropy (information theory)Boundary value problemMathematics
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High Reynolds number Navier-Stokes solutions and boundary layer separation induced by a rectilinear vortex

2013

Abstract We compute the solutions of Prandtl’s and Navier–Stokes equations for the two dimensional flow induced by a rectilinear vortex interacting with a boundary in the half plane. For this initial datum Prandtl’s equation develops, in a finite time, a separation singularity. We investigate the different stages of unsteady separation for Navier–Stokes solution at different Reynolds numbers Re = 103–105, and we show the presence of a large-scale interaction between the viscous boundary layer and the inviscid outer flow. We also see a subsequent stage, characterized by the presence of a small-scale interaction, which is visible only for moderate-high Re numbers Re = 104–105. We also investi…

D'Alembert's paradoxGeneral Computer SciencePrandtl numberMathematics::Analysis of PDEsFOS: Physical sciencesPhysics::Fluid Dynamicssymbols.namesakeMathematics - Analysis of PDEsHagen–Poiseuille flow from the Navier–Stokes equationsFOS: MathematicsSettore MAT/07 - Fisica MatematicaMathematical PhysicsMathematicsMathematical analysisGeneral EngineeringFluid Dynamics (physics.flu-dyn)Reynolds numberPhysics - Fluid DynamicsMathematical Physics (math-ph)Non-dimensionalization and scaling of the Navier–Stokes equationsBoundary layersymbolsTurbulent Prandtl numberReynolds-averaged Navier–Stokes equationsBoundary layer Unsteady separation Navier Stokes solutions Prandtl’s equation High Reynolds number flows.Analysis of PDEs (math.AP)
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A hybrid multi-criteria approach to GPR image mining applied to water supply system maintenance

2018

[EN] Data processing techniques for Ground Penetrating Radar (GPR) image mining provide essential information to optimize maintenance management of Water Supply Systems (WSSs). These techniques aim to elaborate on radargrams in order to produce meaningful graphical representations of critical buried components of WSSs. These representations are helpful non-destructive evaluation tools to prevent possible failures in WSSs by keeping them adequately monitored. This paper proposes an integrated multi-criteria decision making (MCDM) approach to prioritize various data processing techniques by means of ranking their outputs, namely their resulting GPR image representations. The Fuzzy Analytic Hi…

Data processingComputer scienceGPRWater Supply Systems020209 energy02 engineering and technologyFilter (signal processing)Multiple-criteria decision analysiscomputer.software_genreVisualizationIdentification (information)GeophysicsRankingRadargramsGround-penetrating radarSettore ING-IND/17 - Impianti Industriali Meccanici0202 electrical engineering electronic engineering information engineering020201 artificial intelligence & image processingData miningELECTREMATEMATICA APLICADAcomputerFAHPELECTRE III
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Multi-integrals of finite variation

2020

The aim of this paper is to investigate different types of multi-integrals of finite variation and to obtain decomposition results.

Decomposition of multifunctionsFinite variation54C60General Mathematics010102 general mathematics54C6501 natural sciencesFunctional Analysis (math.FA)28B20 26E25 26A39 28B05 46G10 54C60 54C65Mathematics - Functional Analysis28B0526A3926E25Settore MAT/05 - Analisi MatematicaFinite interval variationFOS: MathematicsDecomposition (computer science)Applied mathematicsMathematics - Functional Analysis; Mathematics - Functional Analysis; 28B20 26E25 26A39 28B05 46G10 54C60 54C6528B200101 mathematicsMultivalued integralMathematics46G10
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Probabilistic Logic under Coherence‚ Model−Theoretic Probabilistic Logic‚ and Default Reasoning in System P

2016

We study probabilistic logic under the viewpoint of the coherence principle of de Finetti. In detail, we explore how probabilistic reasoning under coherence is related to model-theoretic probabilistic reasoning and to default reasoning in System P. In particular, we show that the notions of g-coherence and of g-coherent entailment can be expressed by combining notions in model-theoretic probabilistic logic with concepts from default reasoning. Moreover, we show that probabilistic reasoning under coherence is a generalization of default reasoning in System P. That is, we provide a new probabilistic semantics for System P, which neither uses infinitesimal probabilities nor atomic bound (or bi…

Deductive reasoningSettore MAT/06 - Probabilita' E Statistica MatematicaConditional probability assessments conditional constraints probabilistic logic under coherence model-theoretic probabilistic logic g-coherence g-coherent entailment defaultreasoning from conditional knowledge bases System P conditional objects.conditional constraintsLogicDefault logicStatistics::Other StatisticsProbabilistic logic networkConditional probability assessmentsprobabilistic logic under coherenceNon-monotonic logicSystem PMathematicsg-coherent entailmentHardware_MEMORYSTRUCTURESmodel-theoretic probabilistic logicbusiness.industryProbabilistic logicSystem P; g-coherence; conditional objectsCoherence (statistics)default reasoning from conditional knowledge basesProbabilistic argumentationConditional probability assessments; conditional constraints; probabilistic logic under coherence; model-theoretic probabilistic logic; g-coherence; g-coherent entailment; default reasoning from conditional knowledge bases; System P; conditional objects.Philosophyg-coherenceProbabilistic CTLArtificial intelligencebusinessAlgorithmconditional objectsJournal of Applied Non−Classical Logics
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Probabilistic Logic under Coherence, Model-Theoretic Probabilistic Logic, and Default Reasoning

2001

We study probabilistic logic under the viewpoint of the coherence principle of de Finetti. In detail, we explore the relationship between coherence-based and model-theoretic probabilistic logic. Interestingly, we show that the notions of g-coherence and of g-coherent entailment can be expressed by combining notions in model-theoretic probabilistic logic with concepts from default reasoning. Crucially, we even show that probabilistic reasoning under coherence is a probabilistic generalization of default reasoning in system P. That is, we provide a new probabilistic semantics for system P, which is neither based on infinitesimal probabilities nor on atomic-bound (or also big-stepped) probabil…

Deductive reasoningSettore MAT/06 - Probabilita' E Statistica MatematicaKnowledge representation and reasoningComputer scienceDefault logicDivergence-from-randomness modelLogic modelcomputer.software_genreLogical consequenceProbabilistic logic networkConditional probability assessments conditional constraints probabilistic logic under coherence model-theoretic probabilistic logic g-coherence g-coherent entailment default reasoning from conditional knowledge bases System P conditional objectsprobabilistic logic under coherenceNon-monotonic logicProbabilistic relevance modeldefault reasoningmodel-theoretic probabilistic logicbusiness.industryProbabilistic logicProbabilistic argumentationExpert systemg-coherencesystem pProbabilistic CTLArtificial intelligencebusinesscomputerdefault reasoning; g-coherence; model-theoretic probabilistic logic; probabilistic logic under coherence; system p
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Maximal ℓ p ‐regularity of multiterm fractional equations with delay

2020

[EN] We provide a characterization for the existence and uniqueness of solutions in the space of vector-valued sequences l(p) (Z, X)for the multiterm fractional delayed model in the form Delta(alpha)u(n) + lambda Delta(beta)u(n) = Lambda u(n) + u(n-tau) + f(n), n is an element of Z, alpha, beta is an element of R+, tau is an element of Z, lambda is an element of R, where X is a Banach space, A is a closed linear operator with domain D(A) defined on X, f is an element of l(p)(Z,X) and Delta(Gamma) denotes the Grunwald-Letkinov fractional derivative of order Gamma > 0. We also give some conditions to ensure the existence of solutions when adding nonlinearities. Finally, we illustrate our resu…

DelayMaximal l(p)-regularityMultiterm fractionalGeneral MathematicsFractional equationsGeneral EngineeringApplied mathematicsGrunwald-Letnikov derivativeMATEMATICA APLICADAGrünwald–Letnikov derivativeMathematicsMathematical Methods in the Applied Sciences
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Laboratorio collegato al bando UMI Premio Archimede

2013

Viene descritta un'attività laboratoriale svolta nell'ambito del Progetto Lauree Scientifiche, collegata al Bando UMI sul Premio Archimede.

Didattica della Matematica Archimede Laboratorio didatticoDidattica della matematicaSettore MAT/04 - Matematiche Complementari
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