"Electromagnetic scattering." . . "Predictions." . . "Electromagnetic fields." . . "Numerical Mathematics." . . "Numerical mathematics." . "Ray tracing." . . "Galerkin method." . . "Computations." . . "Numerical methods and procedures." . . "Radiofrequency Wave Propagation." . . "Radiofrequency wave propagation." . "MINNESOTA UNIV MINNEAPOLIS SCHOOL OF MATHEMATICS." . . . . "Computational Electromagnetics"@en . . . . . . . . . . . "Progress in the development of fast, error-controllable algorithms for the simulation of electromagnetic scattering throughout the frequency spectrum is reported. Advances are described in the development of (1) accelerated, high-order methods for the solution of general, penetrable scattering problems in the low-to-moderate frequency regime; (2) spectral methods for the solution of approximate high-frequency models (geometrical optics -GO- ); and (3) general error-controllable high-frequency scattering solvers. Major accomplishments include the completion of work on (1) in relation with scalar scattering models and the extension of the algorithms to vector models and composite backgrounds; the design, implementation and refinement of a spectral/discontinuous Galerkin method to resolve the GO model in phase space; the advancement of a spectral inverse ray-tracing approach; the development of methods for the evaluation of high-frequency scattering off composite rough surfaces; the derivation of general high-frequency scattering solvers applicable to both single- and multiple-scattering configurations consisting of bounded obstacles in two and three dimensions; and the analysis and implementation of strategies to account for and accelerate the evaluation of multiple-scattering effects."@en . . . . . . . . "The objective of the effort sponsored by the present contract consists of the development of a suite of numerical algorithms, founded on a rigorous mathematical basis for the accurate and efficient prediction of electromagnetic scattering returns. The techniques are based on Integral equations, perturbation theory and high frequency approximations; general numerical methods will be sought through suitable combinations of these."@en . . . . . . . "Multiple operation." . . "Simulation." . . "High frequency." . . "Integral equations." . . "Perturbation theory." . . "Approximation(mathematics)" . . . . "Algorithms." . . "Operations Research." . . "Efficiency." . .