Function Approximation
Mostrando 13-24 de 213 artigos, teses e dissertações.
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13. Modeling and FPGA-based implementation of an efficient and simple envelope detector using a Hilbert Transform FIR filter for ultrasound imaging applications
Abstract Introduction Although the envelope detection is a widely used method in medical ultrasound (US) imaging to demodulate the amplitude of the received echo signal before any back-end processing, novel hardware-based approaches have been proposed for reducing its computational cost and complexity. In this paper, we present the modeling and FPGA impleme
Res. Biomed. Eng.. Publicado em: 15/01/2018
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14. Improved Electronic Structure and Optical Performance of Bi2Te3-xSex From First-principle Calculations Within TB-mBJ Exchange Potential
Using the first-principle calculations of density functional theory within the (FP-LAPW) method, we have investigated the structural, electronic and optical properties of Bi2Te3-xSex alloys with compositions x = 0, 1, 2 and 3 of Se. The generalized gradient approximation functional of Wu and Cohen (GGA-PBE) is used to calculate ground state structural parame
Mat. Res.. Publicado em: 17/11/2017
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15. Simulation of species concentration distribution in reactive flows with unsteady boundary conditions
Abstract The determination of species concentration profiles in reactive flows with variable inlets is a problem of practical interest to many fields such as in flow reactor transient operation and in cyclic degradable pollutants disposals in watercourses. In these cases, the inflow condition often consists of a time-dependent function, which may imply unste
Braz. J. Chem. Eng.. Publicado em: 2017-10
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16. Multidisciplinary Design Optimization of UAV Under Uncertainty
ABSTRACT: Uncertainty-based multidisciplinary design optimization considers probabilistic variables and parameters and provides an approach to account for sources of uncertainty in design optimization. The aim of this study was to apply a decoupling uncertainty-based multidisciplinary design optimization method without any dependence on probability mathemati
J. Aerosp. Technol. Manag.. Publicado em: 2017-06
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17. A Differential Quadrature Procedure with Direct Projection of the Heaviside Function for Numerical Solution of Moving Load Problem
Abstract Owing to its particular characteristics, the direct discretization of the Dirac-delta function is not feasible when point discretization methods like the differential quadrature method (DQM) are applied. A way for overcoming this difficulty is to approximate (or regularize) the Dirac-delta function with simple mathematical functions. By regularizing
Lat. Am. j. solids struct.. Publicado em: 2016-09
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18. Simple Formulae for Control of Industrial Time Delay Systems
Abstract Control of time delay integrating systems is a challenging and on-going research. In this paper a new structure for control of stable and integrating time delay systems is presented. The control design process is as simple as selection of some constant gains, for which simple formulae are introduced. The design methods are derived analytically, whil
Lat. Am. j. solids struct.. Publicado em: 2016
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19. Elastic analysis of pressurized thick FGM cylinders with exponential variation of material properties using TSDT
AbstractIn this research, the general governing set of differential equations for axisymmetric thick FG pressurized cylinders with exponential function of material properties is derived based on third order shear deformation theory. Afterwards, a general analytical solution of governing equations based on Eigen values problems is conducted for cylinders unde
Lat. Am. j. solids struct.. Publicado em: 2015-06
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20. Comparative Analysis of Ck- and C0-GFEM Applied to Two-dimensional Problems of Confined Plasticity
AbstractFor many practical applications in engineering, a complex structure shows linear elastic behavior over almost all its extension, but exhibits confined plasticity contained in some small critical regions, e.g. stress concentrations in fillets and sharp internal corners. The behavior of C0- and Ck-GFEM is investigated in this class of problems. The fir
Lat. Am. j. solids struct.. Publicado em: 2015-05
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21. Application of nonlocal elasticity and DQM to dynamic analysis of curved nanobeams
In this paper, a new numerical technique, the differential quadrature method (DQM) has been developed for dynamic analysis of the nanobeams in the polar coordinate system. DQ approximation of the required partial derivatives is given by a weighted linear sum of the function values at all grid points. A semicircular arch with small-scale effects is investigat
Lat. Am. j. solids struct.. Publicado em: 2014-10
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22. Ab. initio study of the structural, elastic, electronic and optical properties of Cu3N
Electronic, optical, elastic, properties of Copper nitride (Cu3N) in cubic anti- ReO3 phase have been studied using the full-potential augmented plane waves (FP-LAPW) within density functional theory (DFT) framework. Generalized gradient approximation (GGA), local density approximation (LDA), Perdew - Burke - Ernzerhof generalized parameterization of gradien
Mat. Res.. Publicado em: 01/04/2014
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23. Sensitivity analysis and parameter estimation of heat transfer and material flow models in friction stir welding
Although numerical models of heat transfer and material flow have contributed to understand the underlying mechanisms of friction stir welding (FSW), there are certain input model parameters that can not be easily determined. Thus, the model predictions do not always agree with experimental results. In this work, sensitivity analysis and parameter estimation
Mat. Res.. Publicado em: 08/11/2013
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24. A non-standard optimal control problem arising in an economics application
A recent optimal control problem in the area of economics has mathematical properties that do not fall into the standard optimal control problem formulation. In our problem the state value at the final time the state, y(T) = z, is free and unknown, and additionally the Lagrangian integrand in the functional is a piecewise constant function of the unknown val
Pesqui. Oper.. Publicado em: 2013-04