Solutions of differential equations with regular coefficients by the methods of Richmond and Runge-Kutta

Numerical solutions of the differential equation which describe the electric field within an inhomogeneous layer of permittivity, upon which a perpendicularly-polarized plane wave is incident, are considered. Richmond's method and the Runge-Kutta method are compared for linear and exponential profiles of permittivities. These two approximate solutions are also compared with the exact solutions

Modified Hilbert transform pair and Kramers-Kronig relations for complex permittivities

Modified versions of the Hilbert transform pair and the Kramers-Kronig relations are derived for the complex permittivity of a plasma/dielectric medium which is singular at the frequency of the applied electric field equal to 0. Such a complex permittivity exists when the plasma/dielectric model allows a loss term but no restoring term. Permittivity, in which both loss and restoring terms are included, is shown to satisfy the standard Hilbert transform pair and, thus, the Kramers-Kronig relations

Angular power spectrums and their relationship to autocorrelation functions of aperture antennas

Normalized angular power spectrum representations have been derived for linear and circular aperture antennas in terms of their autocorrelation functions. Examples of their use are given

An analysis of the effects of secondary reflections on dual-frequency reflectometers

The error-producing mechanism involving secondary reflections in a dual-frequency, distance measuring reflectometer is examined analytically. Equations defining the phase, and hence distance, error are derived. The error-reducing potential of frequency-sweeping is demonstrated. It is shown that a single spurious return can be completely nullified by optimizing the sweep width

Transverse electric scattering widths for strips-Fourier transform technique

A technique which is based on Fourier transformations is introduced for predicting scattering widths. For a strip it is shown that explicit determination of the linear current density is not necessary for bistatic or monostatic scattering width calculations. Comparisons of the predictions of the technique are made with the integral equation technique predictions, which do not require explicit evaluations of linear current densities

Electronic compensation for reflector surface distortion to improve radiation pattern characteristics of antennas

A simple procedure is described for determining the excitation coefficients of an array feed which compensates for the surface distortion of a reflector antenna to improve the radiation pattern in such a way as to approximate the performance of the undistorted antenna. A computer simulation for a practical feed array is presented as an example of compensation for the distortion of an actual antenna

Modeling 3-D objects with planar surfaces for prediction of electromagnetic scattering

Electromagnetic scattering analysis of objects at resonance is difficult because low frequency techniques are slow and computer intensive, and high frequency techniques may not be reliable. A new technique for predicting the electromagnetic backscatter from electrically conducting objects at resonance is studied. This technique is based on modeling three dimensional objects as a combination of flat plates where some of the plates are blocking the scattering from others. A cube is analyzed as a simple example. The preliminary results compare well with the Geometrical Theory of Diffraction and with measured data

Project ASSIST: A Comprehensive, Systemic Change Initiative for Middle Level Schools

Presented at the AERA meeting in San Francisco April 2006.Further information may be found on the Middle Level Leadership Center web site at http://education.missouri.edu/orgs/mllc/3A_ast_overview.phpA list of MOspace items relating to Project ASSIST may be found at https://mospace.umsystem.edu/xmlui/handle/10355/3480/browse?value=Project+ASSIST&type=subjectThis is one of three items marked by the Middle Level Leadership Center as Project ASSIST Recommended Readings. The other two items may be found at http://hdl.handle.net/10355/3554 and https://mospace.umsystem.edu/xmlui/handle/10355/3555From 1996 through 1998, the first two-year ASSIST cohort of eight elementary schools, eight middle schools, and nine high schools attended bi-monthly work sessions at the university. The sessions were designed to build the various teams' knowledge of best educational practice and processes for leading change when they returned to their respective schools. The second two-year cohort of schools began in the fall of 1998 and concluded in the summer of 2000. The second cohort included 12 middle schools from across the state of Missouri. The shift to middle schools only was congruent with the goals of the MLLC and its primary focus on middle level leadership. The findings and discussions presented in this paper are drawn from the 1996-1998 and 1998-2000 Project ASSSIT cohorts

Development of electromagnetic analysis methods for large aperture antennas

Both deterministic and statistical analysis methods for investigating large aperture antenna radiation patterns are examined. The effects of surface errors on radiation patterns are discussed