Nonlinear
Mostrando 1-12 de 2856 artigos, teses e dissertações.
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1. Numerical Analysis and Approximate Travelling Wave Solutions for a Higher Order Internal Wave System
ABSTRACT In this work we focus on the numerical solution of a higher order bidirectional nonlinear model of Boussinesq type involving a nonlocal operator. Based on a von Neumann stability analysis for the linearized problem, an efficient and stable scheme for the nonlinear system is proposed. Our method is based on a numerical scheme known from the literatur
Trends in Computational and Applied Mathematics. Publicado em: 2022
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2. Rotational Steady Waves in a Low-pressure Region
ABSTRACT Nonlinear steady rotational waves in a low-pressure region are investigated. The problem is formulated in a simplified canonical domain through the use of a conformal mapping, which flattens the free surface. Steady waves are computed numerically using a Newton’s method and classified into three types. Besides, our results indicate that there is a
Trends in Computational and Applied Mathematics. Publicado em: 2022
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3. Finite element computational development for thermo-mechanical analysis of plane steel structures exposed to fire
Abstract This article presents a numerical formulation based on finite element procedures for application in nonlinear thermo-mechanical analyses of steel planar structures under fire condition. The mechanical properties of structural elements degrade when subjected to high temperatures, resulting in significant reductions in strength and stiffness. Under th
REM - International Engineering Journal. Publicado em: 2022
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4. A Finite-Difference Time-Domain Formulation for Modeling Air Ionization Breakdown Streamers
Abstract A numerical model based on the finite-difference time-domain (FDTD) method is developed for calculating discharge currents and fields produced due air ionization between two electrodes. Electric conductivity σ of the ionized channel between two electrodes is calculated using non-linear equations, i.e., σ is obtained using functions of time. The fu
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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5. A Note on the McCormick Second-Order Constraint Qualification
ABSTRACT The study of optimality conditions and constraint qualification is a key topic in nonlinear optimization. In this work, we present a reformulation of the well-known second-order constraint qualification described by McCormick in 17. This reformulation is based on the use of feasible arcs, but is independent of Lagrange multipliers. Using such a refo
Trends in Computational and Applied Mathematics. Publicado em: 2022
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6. Rotational Solitary Wave Interactions over an Obstacle
ABSTRACT In this work, we investigate the propagation of rotational solitary waves over a submerged obstacle in a vertically sheared shallow water channel with constant vorticity. In the weakly nonlinear, weakly dispersive regime the problem is formulated in the forced Korteweg-de Vries equation framework. The initial value problem for this equation is solve
Trends in Computational and Applied Mathematics. Publicado em: 2022
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7. A Mathematical Model for Accessing Dengue Hemorrhagic Fever in Infants
ABSTRACT A mathematical model was developed to describe the dynamics of the primary infection of dengue virus in infants who were born to a mother immune to some serotype of the dengue virus. The model is given by a system of nonlinear ordinary differential equations with time-dependent variables for the number of dengue virus antibodies of the infant transf
Trends in Computational and Applied Mathematics. Publicado em: 2022
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8. Efficient Low-Complexity Optimized Channel Estimating Methods for OFDM-Based Low-Voltage Broadband Power Line Communication Systems
Abstract Broadband Power Line Communication (BB-PLC) technology enables data transmission for smart grid applications. Nevertheless, channel equalizers are required in the receiver to estimate and compensate for the nonlinear time-variant impulse response and noise interference effects introduced by the BB-PLC channel. In this paper, we append the Particle S
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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9. Using nonlinear models to define production, production rate, and precocity of strawberry cultivars
ABSTRACT The aim of this study was to evaluate, using logistic model, the differences in early production, production rate and total productivity of two strawberry cultivars with transplants from different origins grown in substrate. The experiment was carried out in a randomized block design (RBD), with two strawberry cultivars (Albion and Camarosa) and two
Revista Ceres. Publicado em: 2022
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10. Sulfonylurea resistance in Amaranthus hybridus from southern Brazil
ABSTRACT Amaranthus hybridus is a C4 broadleaf species widely spread across Brazilian agricultural territory. Recently, several herbicide resistance reports have been documented in southern Brazil, including the reports for enolpyruvilshikymate-3-phosphate (EPSPS)- and acetolactate-synthase (ALS)- inhibitors. The objective of this study was to confirm the ex
Revista Ceres. Publicado em: 2022
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11. ECG Signals Classification Using Overlapping Variables to Detect Atrial Fibrillation
ABSTRACT In the present work a method for the detection of the cardiac pathology known as atrial fibrillation is proposed by calculating different information, statistics and other nonlinear measures over ECG signals. The original database contains records corresponding to patients who are diagnosed with this disease as well as healthy subjects. To formulate
Trends in Computational and Applied Mathematics. Publicado em: 2022
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12. O efeito da temperatura do ar na mortalidade por doenças cerebrovasculares no Brasil entre 1996-2017
Resumo As doenças cerebrovasculares (DCV) estão entre as principais causas de mortalidade no mundo e a temperatura do ar é um dos seus fatores de risco, embora sua relação seja pouco estudada no Brasil. Este artigo objetiva investigar a relação entre temperatura do ar e mortalidade por DCV em 10 microrregiões nas cinco grandes regiões brasileiras. F
Ciência & Saúde Coletiva. Publicado em: 2022