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Análise bayesiana de dados funcionais com o uso de processo Gaussiano e metanálise: uma aplicação para a marcha humana
(Universidade Federal de São Carlos, 2019-05-02) Milani, Amanda Buosi Gazon; Salasar, Luis Ernesto Bueno; https://lattes.cnpq.br/5464564215528609; https://lattes.cnpq.br/6613038114757534
The term "functional data" arised to accommodate situations in which each observation can be naturally interpreted as a function. These situations have become increasingly common with the availability of measuring instruments capable of recording large volumes of information with high frequency. In this context, a branch of statistics denominated functional data analysis emerged, in which appropriate methods of analysis were developed. An example of application of these techniques is in the study of human gait. The analysis of human movement is fundamental for understanding the normal movement and for proposing and evaluating preventive or rehabilitation programs. In this work, we will consider angular rotation data of the knee during the gait for a population of individuals without previous lesions with the aim of characterizing individual and population patterns. For this, we consider for each individual a Bayesian regression model with Gaussian process, and the conclusions was illustrated by the proposition of different methods for construction of functional predictive bands. To summarize the conclusions across the different individuals of the population, we propose to apply a Bayesian meta-analysis.
Magnetismo d0 em óxidos de In2O3 e (Sn1-xCex)O2
(Universidade Federal de São Carlos, 2019-05-02) Costa, Maria Helena Carvalho da; Souza, Ernesto Chaves Pereira de; https://lattes.cnpq.br/1505400360366643; Oliveira, Adilson Jesus Aparecido de; https://lattes.cnpq.br/4640148190073166; https://lattes.cnpq.br/7479325887608831
We investigated the structural, optical and magnetic properties of two nanoparticles oxide systems: In2O3, prepared by the high energy mechanical milling process, and (Sn1-xCex)O2 produced by the Pechini method, using different synthesis temperatures and the cerium concentration. The structural and morphological properties of nanoparticles were characterized by X-ray diffraction (XRD) techniques, using the Rietveld refinement, field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution (HRTEM). The chemical composition and valence of the ions were investigated using X-ray photoelectron spectroscopy (XPS). Optical properties were studied using UV-Vis and photoluminescence (PL) techniques. Finally, magnetization measurements were performed using the SQUID magnetometry technique. The XRD measurements and the HRTEM images show that the formation of the cubic phase in In2O3 and the tetragonal SnO2 in the NPs of (Sn1-xCex)O2 as the main phases. In addition, in the process of obtaining the samples, we identified that the 96-h milling in the indium oxide led to the formation of the hexagonal phase, H- In2O3. When synthesizing samples of (Sn1-xCex)O2 at a temperature of 750 °C, an orthorhombic phase, O-SnO2, previously only encountered under high pressure and temperature, was formed. The stabilization of these phases at room temperature was associated with the effect of strain and/or defects that led to the establishment of ferromagnetism in our samples, exhibiting anomalous behaviour depending on the coercivity with temperature. We associate this behaviour to the effect of particle size distribution on the magnetic properties of indium oxide and the surface effects on the NPs of (Sn1-xCex)O2. The ferromagnetic behaviour observed in the NPs was related to the singly ionized oxygen vacancies on the surface of the NPs and with the effect of the strain.