Abstract-Back and Forth Error Compensation and Correction (BFECC) was recently developed for interface computation using a level set method. We show that BFECC can be applied to reduce dissipation and diffusion encountered in a variety of advection steps, such as velocity, smoke density, and image advections on uniform and adaptive grids and on a triangulated surface. BFECC can be implemented trivially as a small modification of the first-order upwind or semi-Lagrangian integration of advection equations. It provides second-order accuracy in both space and time. When applied to level set evolution, BFECC reduces volume loss significantly. We demonstrate the benefits of this approach on image advection and on the simulation of smoke, bubbles in water, and the highly dynamic interaction between water, a solid, and air. We also apply BFECC to dye advection to visualize vector fields.

We show that the bifurcations between dynamical states originating in the nonlinear dynamics of an external-cavity semiconductor laser at constant current can be detected by its terminal voltage V. We experimentally vary the intensity fed back into the gain medium by the external cavity and show that the dc component V(dc) of V tracks the optical intensity-based bifurcation diagram. It is shown using computational results based upon the Lang-Kobayashi model that whereas optical intensity accesses the dynamical-state variable |E|, V is related to population-inversion carrier density N. The change in feedback strength affects N and thereby the quasi-Fermi energy level difference at the p-i-n junction band-gap of the gain medium. The change in the quasi-Fermi energy-level thereby changes the terminal voltage V. Thus V is shown to provide information on the change in the dynamical-state variable N, which complements the more conventionally probed optical intensity.

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-A curvature CPW-fed ultra-wideband monopole antenna on LCP substrate is proposed. The proposed antenna has good performance over the entire UWB frequency range (3.1 -10.6 GHz), which enhanced the impedance bandwidth by adding four notches on rectangular patch. It can be easily mounted in conformal shapes (e.g. cylindrical), because LCP substrate have many attractiveness, especially flexible characteristic, for use in many mm-wave areas. The radiation patterns for both structures have similar performance to the conventional monopole antenna, because the antenna is flexed along its radiating side. The simulated peak-gain variation is less than 5 dBi for both structure, which cover UWB frequency range.

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