We present an approach that takes into account lattice dynamical effects in calculating the optical response of semiconductors by averaging over several perturbed configurations of a supercell extracted from molecular dynamic simulations. The validity of this approach is confirmed by comparing our results for the dielectric function of bulk GaAs in the range of 0 - 700 K with our and other highly accurate ellipsometry measurements. The results of our approach resolve the serious discrepancy in energy and line shape between the latest optical models, all of which neglect lattice dynamics, and experiment

No abstract

No abstract

No abstract

We present a nonlinear model predictive control algorithm for online motion planning and tracking of an omnidirectional autonomous robot. The formalism is based on the minimization of a control Hamiltonian related to the cost function. This minimization is constrained by a nonlinear plant model. The algorithm considers point obstacles and uses a potential field to penalize proximity to those obstacles. A simple and demonstrative example simulation is presented.