Effective complex permittivity tensor of a periodic array of cylinders

We determine the effective complex permittivity of a two-dimensional composite, consisting of an arbitrary doubly periodic array of identical circular cylinders in a homogeneous matrix, and whose dielectric properties are complex-valued. Efficient formulas are provided to determine the effective complex permittivity tensor which are in excellent agreement with numerical calculations. We also show that in contrast to the real-valued case, the real and imaginary parts of the effective complex-valued tensor can exhibit non-monotonic behavior as functions of volume fraction of cylinders, and can be either greater or less than that of the constituents.Comment: 13 pages, 14 figure

On the determination of the boundary impedance from the far field pattern

We consider the Helmholtz equation in the half space and suggest two methods for determining the boundary impedance from knowledge of the far field pattern of the time-harmonic incident wave. We introduce a potential for which the far field patterns in specially selected directions represent its Fourier coefficients. The boundary impedance is then calculated from the potential by an explicit formula or from the WKB approximation. Numerical examples are given to demonstrate efficiency of the approaches. We also discuss the validity of the WKB approximation in determining the impedance of an obstacle.Comment: 10 pages, 4 figure

The effect of disorder on the wave propagation in one-dimensional periodic optical systems

The influence of disorder on the transmission through periodic waveguides is studied. Using a canonical form of the transfer matrix we investigate dependence of the Lyapunov exponent $\gamma$ on the frequency $\nu$ and magnitude of the disorder $\sigma$. It is shown that in the bulk of the bands $\gamma \sim \sigma^2$, while near the band edges it has the order $\gamma \sim \sigma^{2/3}$. This dependence is illustrated by numerical simulations.Comment: 15 pages, 4 figure

AI RE Mission Planning CE: From Integration and Fusion to Adaptive SA at the Tactical Edge

NPS NRP Executive SummaryAI RE Mission Planning CE: From Integration and Fusion to Adaptive SA at the Tactical EdgeII Marine Expeditionary Forces (II MEF)Fleet Numerical Meteorology and Oceanography Center (FNMOC)This research is supported by funding from the Naval Postgraduate School, Naval Research Program (PE 0605853N/2098). https://nps.edu/nrpChief of Naval Operations (CNO)Approved for public release. Distribution is unlimited.

Alien Registration- Godin, Major A. (Westbrook, Cumberland County)

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Improve the Effectiveness of the Decision-Maker Orientation Processes in Making Sense of the Events & Phenomena Presented by the Battlespace

NPS NRP Executive SummaryImprove the Effectiveness of the Decision-Maker Orientation Processes in Making Sense of the Events & Phenomena Presented by the BattlespaceFleet Numerical Meteorology and Oceanography Center (FNMOC)This research is supported by funding from the Naval Postgraduate School, Naval Research Program (PE 0605853N/2098). https://nps.edu/nrpChief of Naval Operations (CNO)Approved for public release. Distribution is unlimited.