Search results for "equation"

showing 10 items of 4219 documents

Corrective meshless particle formulations for time domain Maxwell's equations

2007

AbstractIn this paper a meshless approximation of electromagnetic (EM) field functions and relative differential operators based on particle formulation is proposed. The idea is to obtain numerical solutions for EM problems by passing up the mesh generation usually required to compute derivatives, and by employing a set of particles arbitrarily placed in the problem domain. The meshless Smoothed Particle Hydrodynamics method has been reformulated for solving the time domain Maxwell's curl equations. The consistency of the discretized model is investigated and improvements in the approximation are obtained by modifying the numerical process. Corrective algorithms preserving meshless consiste…

Electromagnetic fieldRegularized meshless methodMathematical optimizationDiscretizationNumerical analysisApplied MathematicsMeshless particle methodMaxwell's equationSmoothed particle hydrodynamicsElectromagnetic transientsSmoothed-particle hydrodynamicssymbols.namesakeSettore MAT/08 - Analisi NumericaSettore ING-IND/31 - ElettrotecnicaComputational MathematicsMaxwell's equationsMaxwell's equationsMesh generationsymbolsElectromagnetic transientApplied mathematicsTime domainMathematicsJournal of Computational and Applied Mathematics
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Highly efficient full-wave electromagnetic analysis of 3-D arbitrarily shaped waveguide microwave devices using an integral equation technique

2015

A novel technique for the full-wave analysis of 3-D complex waveguide devices is presented. This new formulation, based on the Boundary Integral-Resonant Mode Expansion (BI-RME) method, allows the rigorous full-wave electromagnetic characterization of 3-D arbitrarily shaped metallic structures making use of extremely low CPU resources (both time and memory). The unknown electric current density on the surface of the metallic elements is represented by means of Rao-Wilton-Glisson basis functions, and an algebraic procedure based on a singular value decomposition is applied to transform such functions into the classical solenoidal and nonsolenoidal basis functions needed by the original BI-RM…

Electromagnetic fieldSolenoidal vector fieldbusiness.industryAcousticsBoundary (topology)Basis functionCondensed Matter PhysicsIntegral equationlaw.inventionOpticslawSingular value decompositionGeneral Earth and Planetary SciencesElectrical and Electronic EngineeringCoaxialbusinessWaveguideMathematicsRadio Science
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A deep study of the high–energy transient sky

2021

This is an open access article. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds t…

Electromagnetic spectrumESA voyage 2050; High-energy transient sky; Multi-messenger astrophysics; Space mission concept; X–/γ–ray polarimetry; X–/γ–ray telescopes01 natural sciences7. Clean energylaw.inventionSettore FIS/05 - Astronomia E AstrofisicalawNuclear astrophysicsoptical010303 astronomy & astrophysicsmedia_commonPhysicsdensityStrong gravityAstrophysics::Instrumentation and Methods for AstrophysicsnucleosynthesisimagingParticle accelerationHigh-energy transient skyNeutrinoburstparticlelensmedia_common.quotation_subjectAstrophysics::High Energy Astrophysical PhenomenainterferometerSpace mission conceptTelescope0103 physical sciencesTeVequation of statepolarization010308 nuclear & particles physicsGravitational wavenucleusgravitational radiationAmbientaleAstronomyAstronomy and AstrophysicsaccelerationsensitivityMulti-messenger astrophysicsUniversemonitoringelectromagneticX–/γ–ray telescopesangular resolution[SDU]Sciences of the Universe [physics]13. Climate actionSpace and Planetary Sciencegamma raygravitationX–/γ–ray polarimetry[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]ESA voyage 2050
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The role of travel motivations and social media use in consumer interactive behaviour: a uses and gratifications perspective

2020

This paper explores the influence of travel motivations and the gratification provided by social media in consumer stickiness to social media, intention to create user-generated content, and electronic word of mouth (eWOM) review adoption. The study follows a mixed-methods approach. First, a concept mapping study was undertaken to identify the main travel motivations and the gratifications provided by social media when consumers search for information on tourism destinations. A second study using structural equation modelling and SmartPLS 3.2.7 with a sample of 401 heavy users of social media showed the relationships between individual travel motivations and gratifications provided by socia…

Electronic word of mouthsocial medialcsh:TJ807-830Geography Planning and Developmentlcsh:Renewable energy sourcesUser-generated contentuses and gratificationsstickinessSample (statistics)Management Monitoring Policy and Lawtravel motivations:CIENCIAS ECONÓMICAS [UNESCO]Structural equation modeling0502 economics and businessewomSocial mediaSociologylcsh:Environmental scienceslcsh:GE1-350GratificationRenewable Energy Sustainability and the EnvironmentConcept maplcsh:Environmental effects of industries and plants05 social sciencesPerspective (graphical)UNESCO::CIENCIAS ECONÓMICASAdvertisinglcsh:TD194-195eWOM050211 marketing050212 sport leisure & tourismuser-generated content
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Personalization of Fast Conduction Purkinje System in Eikonal-Based Electrophysiological Models with Optical Mapping Data

2010

We present a pipeline for the personalization of model-based Purkinje fast conduction system using fast electrophysiological models and optical mapping data acquired from ex-vivo porcine hearts. The regional density of the Purkinje terminals as well as the latest endocardial activation time were the parameters personalized in an iterative procedure maximizing the similarity between the outcome of the electrophysiological simulations and measurements obtained from optical mapping data. We used a fast wave-front Eikonal-based electrophysiological model that generated the depolarization time maps that were subsequently compared with measurements at each iteration of the optimization stage. The…

ElectrophysiologySimilarity (geometry)Computer scienceEikonal equationPipeline (computing)Optical mappingExperimental dataElectrical conduction system of the heartAlgorithmSimulationPersonalization
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On ( p ( x ),  q ( x ))‐Laplace equations in ℝN without Ambrosetti‐Rabinowitz condition

2021

In the present work, we consider a (p(x), q(x))-elliptic equation describing the behavior of a double-phase anisotropic problem which has relevance in electrorheological fluid applications. The analysis leads to the existence of weak (nonnegative) solutions in the special case of potential terms with critical frequency and a superlinear reaction term. In order to prove the existence result, we combine critical point theory of mountain pass type with related topological and variational methods. Basically, the approach is variational, but we do not impose any Ambrosetti-Rabinowitz type condition for the superlinearity of the reaction. More specifically, we apply the Euler-Lagrange functional …

Elliptic curvevariable exponentLaplace transformVariable exponentCritical frequencyelliptic equationGeneral MathematicsMathematical analysisGeneral Engineering(p(x) q(x))-Laplace operatorcritical frequencyMathematicsMathematical Methods in the Applied Sciences
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Boundary accessibility and elliptic harmonic measures

1988

Suppose G is a bounded domain in R n such that the complement of G satisfies a capacity dcnsity condition. It is shown that all elliptic measures in G have a support set with Moreover, the capacity density condition cannot be removed. A nonlinear version of the result is also given.

Elliptic operatorNonlinear systemPartial differential equationBounded functionMathematical analysisBoundary (topology)Harmonic (mathematics)General MedicineDomain (mathematical analysis)Complement (set theory)MathematicsComplex Variables, Theory and Application: An International Journal
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High order normal form construction near the elliptic orbit of the Sitnikov problem

2011

We consider the Sitnikov problem; from the equations of motion we derive the approximate Hamiltonian flow. Then, we introduce suitable action–angle variables in order to construct a high order normal form of the Hamiltonian. We introduce Birkhoff Cartesian coordinates near the elliptic orbit and we analyze the behavior of the remainder of the normal form. Finally, we derive a kind of local stability estimate in the vicinity of the periodic orbit for exponentially long times using the normal form up to 40th order in Cartesian coordinates.

Elliptic orbitNormal formPerturbation theoryExponential stabilitylaw.inventionsymbols.namesakeExponential stabilitylawCartesian coordinate systemHigh orderRemainderSettore MAT/07 - Fisica MatematicaMathematical PhysicsMathematicsApplied MathematicsMathematical analysisBirkhoff coordinatesEquations of motionAstronomy and AstrophysicsSitnikov problemComputational MathematicsSpace and Planetary ScienceModeling and SimulationSitnikov problemsymbolsBirkhoff coordinates; Exponential stability; Lie-series expansions; Normal form; Perturbation theory; Sitnikov problem; Astronomy and Astrophysics; Space and Planetary ScienceHamiltonian (quantum mechanics)Lie-series expansions
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Associations between structures, processes and outcomes in inter-municipal cooperation in out-of-hours services in Norway: A survey study

2020

Abstract Inter-municipal cooperation (IMC) has gained widespread recognition as a beneficial strategy for improving efficiency and quality in the provision of out-of-hours emergency care services (OOH services). Little attention, however, has been given to the additional costs of cooperation and the relational processes through which benefits and costs are likely to result. Based on survey data from 266 (77%) Norwegian municipalities involved in IMC in OOH services in 2015, this study aimed to investigate how the structure (governance form, complexity and stability) and quality (trust and consensus) of cooperation processes interact to influence the perceived outcomes (benefits and costs) o…

Emergency Medical ServicesHealth (social science)media_common.quotation_subjectStructural equation modeling03 medical and health sciences0302 clinical medicineOut of hoursAfter-Hours CareHistory and Philosophy of ScienceSurveys and QuestionnairesHumansQuality (business)030212 general & internal medicinemedia_commonPublic economicsNorway030503 health policy & servicesCorporate governanceSurvey researchVDP::Medisinske Fag: 700::Idrettsmedisinske fag: 850Peer reviewInter-municipal cooperationVDP::Medisinske Fag: 700::Helsefag: 800Survey data collectionBusiness0305 other medical scienceSocial Science & Medicine
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Student behavioral engagement as a mediator between teacher, family, and peer support and school truancy

2014

This study investigated the associations between student's behavioral engagement; teacher, family, and peer emotional support; and school truancy. Student-reported data of 821 Finnish junior high school students were analyzed using structural equation modeling. Teacher and family support were positively associated with student behavioral engagement, which in turn was negatively associated with truancy. Behavioral engagement mediated the associations between teacher and family emotional support and truancy. The results highlight the pivotal roles of teacher and family emotional support in fostering student behavioral engagement and preventing truancy in junior high schools. Students who are …

Emotional supportSocial PsychologyFamily supporteducationemotional supportStudent engagementPeer supportSocial control theoryStructural equation modelingEducationsocial control theoryBehavioral engagementmental disordersstudent engagementDevelopmental and Educational Psychologyparticipation-identification modelta516TruancyPsychologyschool truancySocial psychologyLearning and Individual Differences
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