Semigroup Theory
Mostrando 1-10 de 10 artigos, teses e dissertações.
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1. Estabilização assintótica e controle no problema de conexões em série de vigas / Asymptotic stabilization and control in the problem of serially connected beams
In this work, we study the modell of a system of N beams interconnected with each other, where one of its ends is clamped and the other is submitted to a dissipative mechanism of frictional type. We show that model is well posed, using the semigroup theory, and using energy method, we prove that the system is exponentially stable. Finally, through numerical
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/09/2010
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2. An explicit formulation for the inverse transport problem using only external detectors: Part I: computational modelling
In the present work the inverse problem of identification of radiative properties, the total extinction and scattering coefficients, is analyzed and explicitly formulated based in an elementary semi-group theory. The Chandrasekhar discrete ordinates finite dimensional approximation of the angular variables is used for the direct problem representation with t
Computational & Applied Mathematics. Publicado em: 2010
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3. SoluÃÃes globais e nÃo - globais de uma equaÃÃo parabÃlica nÃo - linear
We study the behaviour of solutions for the nonlinear heat equation with Dirichlet boundary conditions on a bounded subset of RN. We introduce the notion of weak solutions for this type of problem, and study the relation between such solutions and weak solutions for the associated stationary elliptic problem. Basic notions on Lebesgue spaces, Sobolev spaces,
Publicado em: 2008
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4. Semigroups generated by cosets and characteristics functions of semigroups / Semigrupos gerados por classes laterais e funções caracteristicas de semigrupos
This work is made of two parts. In the first one, we gave necessary and sufficient conditions for a family of cosets of a Lie subgroup to generate a subsemigroup with nonempty interior. We apply these conditions to symmetric pairs where the group is semi-simple. As a consequence we prove that for several involutive automorphisms the fixed points subgroup is
Publicado em: 2007
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5. Teoria de semigrupos e aplicações a equações impulsivas com retardamento dependendo do estado / Semigroup theory and applications to impulsive differential equation with state-dependent delay
In this work we stablish the existence of mild solutions for an impulsive abstract functional differential equation with state-dependent delay described in the form x POT. PRIME(t) = Ax(t) + f(t;x IND. p(t, xt)), t BELONGSI = [0,a], x IND. 0=\varphi IS CONTAINEDB, DELTAx(t IND. i) = I IND.ii(x IND.i); i = 1, ...n, where A is the infinitesimal generator of a
Publicado em: 2006
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6. Semigroup theory and controllability of neutral systems / Teoria de semigrupos e controlabilidade de sistemas neutros
Neste trabalho de dissertação de mestrado, fazemos algumas observações a respeito de dois¶ artigos de pesquisa recentes, os quais estabelecem resultados falsos sobre existência de soluções controlabilidade exata de sistemas de controle abstratos do tipo neutro modelados na forma¶8<:¶ d ¶ dt ¶(x(t) + G(t, xt)) = Ax(t) + F(t, xt) + Cu(t), t 2 I = (
Publicado em: 2006
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7. Infinitesimal generators and quasi-units in potential theory
The underlying structure is taken as a strongly superharmonic cone [unk], defined as a partially ordered abelian semigroup with identity 0 which admits a multiplication by nonnegative scalars and satisfies two fundamental axioms of a potentialtheoretic character. In terms of a fixed nonzero element e there is introduced on [unk] a one-parameter family of non
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8. GENERATING FUNCTIONS AND THE SEMIGROUP THEORY OF BRANCHING MARKOV PROCESSES*
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9. The second law as a selection principle: The microscopic theory of dissipative processes in quantum systems
The second law of thermodynamics, for quantum systems, is formulated, on the microscopic level. As for classical systems, such a formulation is only possible when specific conditions are satisfied (continuous spectrum, nonvanishing of the collision operator, etc.). The unitary dynamical group can then be mapped into two contractive semigroups, reaching equil
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10. Microscopic theory of irreversible processes
The microscopic theory of irreversible processes that we developed is summarized and illustrated, using as a simple example the Friedrichs model. Our approach combines the Poincaré's point of view (dynamical interpretation of irreversibility) with the Gibbs-Einstein ensemble point of view. It essentially consists in a nonunitary transformation theory based