Nonlinear System
Mostrando 1-12 de 659 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 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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3. 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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4. 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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5. Low-Overhead Low-Complexity Carrier Phase Recovery Technique for Coherent Multi-Band OFDM-Based Superchannel Systems Enabled by Optical Frequency Combs
Abstract In this paper, we have designed a low-overhead low-complexity carrier phase tracking scheme for OFDM-based superchannel transmission system enabled by optical frequency combs. In this scheme, taking advantage of the broadband phase coherence provided by optical frequency combs among the OFDM-bands, the carrier phase retrieved from pilot-subcarriers
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-03
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6. INTRODUÇÃO ÀS REDES NEURAIS PARA REGRESSÕES NÃO-LINEARES: AJUSTE DE SUPERFÍCIES DE ENERGIA POTENCIAL
The present work demonstrates how neural networks are used to do non-linear regressions. The technique is presented in a simple and didactic manner and applied to fit potential energy surfaces for the FeC molecule and for the reaction H + H2. It shows how to do the fitting for single- and multi-variable system providing examples and code that can be easily e
Quím. Nova. Publicado em: 2021-02
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7. Analysis and Optimization of Ultra-Low-Power Rectifier with High Efficiency for Applications in Wireless Power Transmission and Energy Harvesting
Abstract The system capable of harvesting RF energy from the environment through an antenna and converting it into direct current energy to deliver to a load is known as rectenna. The rectifier circuit is an important part of the rectenna and its modeling is arduous since it employs a non-linear device working at extremely low power levels. In addition, ther
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-03
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8. ANALYTICAL EXPRESSIONS FOR THE CONCENTRATION AND CURRENT IN THE REDUCTION OF HYDROGEN PEROXIDE AT A METAL-DISPERSED CONDUCTING POLYMER FILM
A mathematical model describing the reduction of Hydrogen peroxide (H2O2) to water in a metal dispersed conducting polymer film is discussed. The model is based on a system of reaction-diffusion equations containing a non-linear term related to Michaelis-Menten kinetics of the enzymatic reaction. The approximate analytical expressions corresponding to the co
Quím. Nova. Publicado em: 2020-01
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9. A METHODOLOGY TO OBTAIN ANALYTICAL MODELS THAT REDUCE THE COMPUTATIONAL COMPLEXITY FACED IN REAL TIME IMPLEMENTATION OF NMPC CONTROLLERS
Abstract Model Predictive Control, MPC and NMPC, and real-time optimization, RTO and D-RTO, are known to help plant operability through the mitigation of impacts caused by external disturbances. However, the usage of these tools in industry requires overcoming some challenges, for instance: accurate models of the process, particularly in regard to nonlineari
Braz. J. Chem. Eng.. Publicado em: 09/12/2019
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10. Oscilador Harmônico Duplo difuso
Resumo A descrição do comportamento de um sistema difuso, linear e não-linear, pode ser tratada através da equação de Fokker-Planck. Esta equação tem despertado grande interesse de pesquisadores por sua boa adaptação a diferentes sistemas, tanto clássicos como quânticos. Neste trabalho, utilizamos a equação de Fokker-Planck para encontrar as pr
Rev. Bras. Ensino Fís.. Publicado em: 25/11/2019
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11. The Psychophysiological Responses of the Chronic Ischemic Stroke Patients to the Acute Stress were Changed
Abstract: Mood disorder is one of the complications of stroke. The inability to cope with stress is also a prognosis of depression and anxiety. The aim of this study is to assess the response of stress system in the post stroke patients. Twelve healthy controls (HC) and twelve post-stroke patients after filling in the State-Trait Anxiety Inventory completed
Braz. arch. biol. technol.. Publicado em: 25/11/2019
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12. Summer Cover Crops Shoot Decomposition and Nitrogen Release in a No-Tilled Sandy Soil
ABSTRACT Cover crops have numerous benefits when used in a no-till system. Understanding the processes of decomposition and N release of summer cover crops (SCC) may help select species and management to be used in cropping systems. This study aimed to evaluate C and N loss of SCC shoots. Six SCCs were evaluated: velvet bean (Mucuna aterrima), pearl millet (
Rev. Bras. Ciênc. Solo. Publicado em: 07/11/2019