Research Reports

11/1998 Quais Anéis Moram em Álgebras de Dimensão Finita - I: Uma História de Uma Teoria
Alexandre Ananin
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11/1998 Generating inexact-Newton methods using least change secant update procedures
José Mario Martínez
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10/1998 A View to Classification of Algebras
Alexandre Ananin
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9/1998 Partitions with "[(N + 1)/2] copies of N"
José Plínio O. Santos, Paulo Mondek
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8/1998 Derivation of Cubic Splines from Cubic Hermite Functions
Saulo Pomponet Oliveira, Petrônio Pulino
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7/1998 The Center-Focus Problem and Reversibility
Marco A. Teixeira, Jiazhong Yang
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6/1998 Controllability of discrete-time control systems on the symplectic group
Carlos J. Braga Barros, Luiz A. B. San Martin

Let x_{n+1} = exp(A+uB)x_{n} be a discrete-time control system on R^{2n}with A and B matrices in the symplectic Lie algebra sp(n, R). This papergives sufficient conditions for the global controllability of the system. Theseconditions are similar to those of [4].


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5/1998 On an Iterative Method for the Approximate Solution of an Initial and Boundary-Value Problem for a Generalized Boussinesq Model
M. Drina Rojas-Medar, Marko A. Rojas-Medar

In this work an iteractive method is proposed for finding the approximate solution of an initial and boundary problem for a nonstationary Generalized Boussinesq model for thermally driven convection. The model allows temperature dependent viscosity and thermal conductivity. We give also the convergence rate bounds for the propost method.


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4/1998 Reconstruction Of A Compactly Supported Function From The Discrete Sampling Of Its Fourier Transform
Jiahong Yin, Alvaro R. De Pierro, Musheng Wei

We derive a new relation between the Discrete Fourier Transform of a discrete sampling set of a compactly supported function and its Fourier transform. From this relation we obtain a new window function. We then propose a new efficient algorithm to reconstruct the original function from the discrete sampling of its Fourier transform, which can adopt the fast Fourier transform and has much better accuracy than those in the literature. Several numerical experiments are also provided to demonstrate the results.


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3/1998 On the number of control sets on flag manifolds of the real simple Lie groups
Carlos J. Braga Barros
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