Narrow Results

Addressed is the physics of sound propagation through a shallow water waveguide whose seabed has a random rough surface. The basic coupled integral equations for the modal amplitudes can be split into forward and backward going coupled integral equations. Numerical solutions of the coupled equations are obtained for multiple roughness realizations from which ensemble averages can be obtained for the modal intensities and cross-mode coherence as a function of range. Sample calculations illustrate some of the basic characteristics of the average cross-mode coherence and intensity with and without seabed attenuation and for different source depths on range scales of 1500 acoustic wavelengths.

Recent works have shown that the model of random Boolean networks, properly modified in order to take into account the influence of random fluctuations, can describe a set of phenomena which are related to cell differentiation. The main results are summarized here, and the methodological implications of this kind of models are discussed.