Search results for "Integral equations"

showing 4 items of 24 documents

On modified α-ϕ-fuzzy contractive mappings and an application to integral equations

2016

Abstract We introduce the notion of a modified α-ϕ-fuzzy contractive mapping and prove some results in fuzzy metric spaces for such kind of mappings. The theorems presented provide a generalization of some interesting results in the literature. Two examples and an application to integral equations are given to illustrate the usability of our theory.

integral equationsGeneralization02 engineering and technologyFixed point01 natural sciencesFuzzy logicSettore MAT/05 - Analisi Matematica0202 electrical engineering electronic engineering information engineeringmodified α-ϕ-fuzzy contractive mappingDiscrete Mathematics and Combinatorics0101 mathematicsα-admissible mapping with respect to ηMathematicsDiscrete mathematicsbusiness.industryApplied Mathematicslcsh:MathematicsUsabilitylcsh:QA1-939Integral equationFuzzy metric space010101 applied mathematicsAlgebraintegral equationfixed point020201 artificial intelligence & image processing$alpha$-admissible mapping with respect to $eta$ fixed point modified $alpha$-$phi$-fuzzy contractive mapping integral equationsbusinessAnalysisJournal of Inequalities and Applications
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On the Fast and Rigorous Analysis of Compensated Waveguide Junctions Using Off-Centered Partial-Height Metallic Posts

2007

In this paper, we present an efficient and rigorous method, based on the 3-D boundary integral-resonant-mode expansion technique, for the analysis of multiport rectangular waveguide junctions compensated with partial-height cylindrical metallic posts. The electrical performance of a great variety of commonly used wideband microwave circuits has been improved drastically thanks to the introduction of a new design parameter, i.e., the relative position of the metallic post in the structure. To the authors' knowledge, this parameter has not been taken into account in previous studies concerning compensated junctions using partial-height metallic posts. The developed tool has been successfully …

integral equationsmethod of momentsRadiationbusiness.industryAcousticsNumerical analysiswaveguide junctionsMethod of moments (statistics)Condensed Matter PhysicsWaveguide (optics)Finite element methodcompensationOpticsPower dividers and directional couplerswaveguide componentsElectrical and Electronic EngineeringWidebandbusinessMicrowaveElectronic circuitMathematicsIEEE Transactions on Microwave Theory and Techniques
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Multi-parameter analysis of the obstacle scattering problem

2022

Abstract We consider the acoustic field scattered by a bounded impenetrable obstacle and we study its dependence upon a certain set of parameters. As usual, the problem is modeled by an exterior Dirichlet problem for the Helmholtz equation Δu + k 2 u = 0. We show that the solution u and its far field pattern u ∞ depend real analytically on the shape of the obstacle, the wave number k, and the Dirichlet datum. We also prove a similar result for the corresponding Dirichlet-to-Neumann map.

integral equationsshape sensitivity analysisassociated exterior Dirichlet problemDirichlet-to-Neumann operatorApplied MathematicsHelmholtz equation; acoustic scattering; associated exterior Dirichlet problem; Dirichlet-to-Neumann operator; shape sensitivity analysis; perturbed domain; integral equationsacoustic scatteringComputer Science ApplicationsTheoretical Computer Scienceperturbed domainMathematics - Analysis of PDEsSettore MAT/05 - Analisi MatematicaSignal ProcessingFOS: Mathematicsacoustic scattering; associated exterior Dirichlet problem; Dirichlet-to-Neumann operator; Helmholtz equation; integral equations; perturbed domain; shape sensitivity analysisHelmholtz equation35J25 35J05 35P25 31B10 45A05Mathematical PhysicsAnalysis of PDEs (math.AP)
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Dependence of effective properties upon regular perturbations

2022

In this survey, we present some results on the behavior of effective properties in presence of perturbations of the geometric and physical parameters. We first consider the case of a Newtonian fluid flowing at low Reynolds numbers around a periodic array of cylinders. We show the results of [43], where it is proven that the average longitudinal flow depends real analytically upon perturbations of the periodicity structure and the cross section of the cylinders. Next, we turn to the effective conductivity of a periodic two-phase composite with ideal contact at the interface. The composite is obtained by introducing a periodic set of inclusions into an infinite homogeneous matrix made of a di…

perturbed domainintegral equationsSettore MAT/05 - Analisi Matematicatransmission problemEffective conductivity; Integral equations; Longitudinal flow; Periodic composite; Perturbed domain; Transmission problemperiodic compositeeffective conductivityLongitudinal flow
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