Nonlinear Time Series
Mostrando 1-12 de 100 artigos, teses e dissertações.
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1. Linear and Nonlinear Heart Rate Variability Analysis in Gonadal Dysgenesis (Swyer Syndrome): A Case Report
Abstract Swyer syndrome is one of the disorders of sexual differentiation. Previous studies have demonstrated increased sympathetic activity with heart rate variability (HRV) analysis with decreasing estradiol levels. One patient presented a pure 46, XY gonadal dysgenesis with female phenotype. Cardiac autonomic modulation was assessed through HRV analysis w
Int. J. Cardiovasc. Sci.. Publicado em: 2021-08
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2. Long-Term Correlations in São Francisco River Flow: The Influence of Sobradinho Dam
Resumo Neste trabalho estudamos a influência da construção da barragem de Sobradinho na vazão diária do rio São Francisco, Brasil, analisando correlações de longo alcance em séries temporais de magnitude e sinal obtidas a partir da anomalia das vazões utilizando o método Detrended Fluctuation Analysis. A série de magnitude está relacionada com a
Rev. bras. meteorol.. Publicado em: 05/08/2019
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3. A detailed comparison of oxygen uptake kinetics at a range of exercise intensities
Abstract Aim: The aim of this study was to comprehensively examine oxygen uptake (V̇O2) kinetics during cycling through mathematical modeling of the breath-by-breath gas exchange responses across eight conditions of unloaded cycling to moderate to high-intensity exercise. Methods: Following determination of GET and V̇O2peak, eight participants (age: 24±
Motriz: rev. educ. fis.. Publicado em: 29/04/2019
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4. Modeling and Experimental Validation of Two Adjacent Portal Frame Structures Subjected to Vibro-impact
Abstract In many engineering applications, there are systems that exhibit a series of collisions in a certain amount of time, for example the impact of floating ice in ships and the rubbing between stationary and rotary parts in turbomachinery. In many of these situations, it is of vital importance to know how the impacts affect the overall system behavior f
Lat. Am. j. solids struct.. Publicado em: 08/04/2019
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5. Simple but accurate periodic solutions for the nonlinear pendulum equation
Abstract Despite its elementary structure, the simple pendulum oscillations are described by a nonlinear differential equation whose exact solution for the angular displacement from vertical as a function of time cannot be expressed in terms of an elementary function, so either a numerical treatment or some analytical approximation is ultimately demanded. Su
Rev. Bras. Ensino Fís.. Publicado em: 21/09/2018
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6. Effects of resistance training protocols on nonlinear analysis of heart rate variability in metabolic syndrome
Despite the various standard non-linear measurements used in autonomic modulation (AM) assessments usually being applied to long time-series, such analyses can sometimes be applied to shorter term series. To overcome this disadvantage, chaotic global methods were formulated by putting together heart rate variability (HRV) linear methods. Chaos provides infor
Braz J Med Biol Res. Publicado em: 11/06/2018
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7. Updating of a Nonlinear Finite Element Model Using Discrete-Time Volterra Series
Abstract In this study, the discrete-time Volterra series are used to update parameters in a nonlinear finite element model. The main idea of the Volterra series is to describe the discrete-time output of a nonlinear system using multidimensional convolutions between the Volterra kernels represented in a Kautz orthogonal basis and the excitations. A metric b
Lat. Am. j. solids struct.. Publicado em: 2017-08
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8. Artificial neural network for prediction of the area under the disease progress curve of tomato late blight
ABSTRACT: Artificial neural networks (ANN) are computational models inspired by the neural systems of living beings capable of learning from examples and using them to solve problems such as non-linear prediction, and pattern recognition, in addition to several other applications. In this study, ANN were used to predict the value of the area under the diseas
Sci. agric. (Piracicaba, Braz.). Publicado em: 2017-02
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9. Classification of Flying Insects with high performance using improved DTW algorithm based on hidden Markov model
ABSTRACT Insects play significant role in the human life. And insects pollinate major food crops consumed in the world. Insect pests consume and destroy major crops in the world. Hence to have control over the disease and pests, researches are going on in the area of entomology using chemical, biological and mechanical approaches. The data relevant to the fl
Braz. arch. biol. technol.. Publicado em: 23/01/2017
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10. Simplified Analytical Approach to Evaluate the Nonlinear Dynamics of Elastic Cylindrical Shells Under Lateral Blast Loads
Abstract This paper presents an analytical solution to predict the nonlinear forced vibrations of elastic thin-walled cylindrical shells under suddenly applied loads. Interest in this problem is motivated by effects due to explosions on fluid-storage metal tanks. The model is based on the energy criterion due to Lagrange, in which the kinematic nonlinear rel
Lat. Am. j. solids struct.. Publicado em: 2016-07
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11. Fire response of a 3D multi-storey building with buckling restrained braces
Abstract This paper investigates the performance of a three-dimensional multi-storey structure with Buckling Restrained Brace system (BRBs) under fire condition, using a sequentially coupled nonlinear thermal stress analysis. Efficiency of using BRBs in enhancing the strength and stiffness of a structural frame is compared with that of Ordinary Concentricall
Lat. Am. j. solids struct.. Publicado em: 2015-11
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12. Long-term correlation of the electrocorticogram as a bioindicator of brain exposure to ionizing radiation
Understanding the effects of radiation and its possible influence on the nervous system are of great clinical interest. However, there have been few electrophysiological studies on brain activity after exposure to ionizing radiation (IR). A new methodological approach regarding the assessment of the possible effects of IR on brain activity is the use of line
Braz J Med Biol Res. Publicado em: 12/06/2015