Omnidirectional vision systems can provide panoramic alertness in surveillance, improve navigational capabilities, and produce panoramic images for multimedia. Catadioptric realizations of omnidirectional vision combine reflective surfaces and lenses. A particular class of them, the central panoramic systems, preserve the uniqueness of the projection viewpoint. In fact, every central projection...

The goal of this paper is to provide an intuitive and useful tool for analyzing the impurity-bound-state problem. We develop a semiclassical approach and apply it to an impurity in two-dimensional systems with parabolic or Dirac-like bands. Our method consists of reducing a higher-dimensional problem into a sum of one-dimensional ones using the two-dimensional Green’s functions as a guide. We t...

The goal of this paper is to provide an intuitive and useful tool for analyzing the impurity bound state problem. We develop a semiclassical approach and apply it to an impurity in two dimensional systems with parabolic or Dirac like bands. Our method consists of reducing a higher dimensional problem into a sum of one dimensional ones using the two dimensional Green functions as a guide. We the...

We consider a general class of one-dimensional parabolic systems, mainly coupled in the diffusion term, which, in fact, can be of the degenerate type. We derive some new L1-gradient type estimates for its solutions which are uniform in the sense that they do not depend on the coefficients nor on the size of the spatial domain. We also give some applications of such estimates to gas dynamics, fi...

State feedback design for linear parabolic systems with in-domain actuation and general Robin boundary conditions is considered. To this end the system is shown to be state equivalent to a boundary controlled system. By means of the well established backstepping transformation this latter system is feedback equivalent to a stable parabolic equation. Within the contribution previous results conc...

A class of generalized approximate inverse finite element matrix algorithmic methods for solving nonlinear parabolic and elliptic PDE’s, is presented. Fully parameterized singularly perturbed non-linear parabolic and elliptic PDE’s are considered and explicit preconditioned generalized conjugate gradient type schemes are presented for the efficient solution of the resulting nonlinear systems of...

A simple model for the dynamics of dunes is introduced. The model simulates formation processes of typical shapes dunes: transverse dunes, barchans, seif dunes, star dunes, parabolic dunes and elongated parabolic dunes according to several environmental factors. The results have qualitative correspondence to the real systems. Considering the simplicity of the algorithm and the consequent easine...

This note presents a comparative study of shock profiles in dissipative systems. Main assumption is that both hyperbolic and parabolic model are reducible to the same underlying equilibrium system when dissipative effects are neglected. It will be shown that the highest characteristic speed of equilibrium system determines the critical value of the shock speed for which downstream equilibrium s...

In this paper we introduce and explore conformal parabolic iterated function systems. We deene and study topological pressure, Perron-Frobenius type operators, semi-conformal and conformal measures and the Hausdorr dimension of the limit set. With every parabolic system we associate an innnite hyperbolic conformal iterated function system and we employ it to study geometric and dynamical featur...

In this paper, we consider the solution of linear systems of algebraic equations that arise from parabolic finite element problems. We introduce three additive Schwarz type domain decomposition methods for general, not necessarily selfadjoint, linear, second order, parabolic partial differential equations and also study the convergence rates of these algorithms. The resulting preconditioned lin...