We consider the following communications system: A mobile cellular telephone company would like to serve K users simultaneously. Each user (transmitter) transmits data to the company’s base station (receiver) in the form of bits (0’s and 1’s). By modulating electromagnetic waves of different frequencies, each user’s data can be transmitted on a fixed set of “frequency slots” approved the govern...

In this paper, we present a nonparametric method to estimate the heterogeneity of a random medium from the angular distribution of intensity of waves transmitted through a slab of random material. Our approach is based on the modeling of forward multiple scattering using compound Poisson processes on compact Lie groups. The estimation technique is validated through numerical simulations based o...

Indirect noise generated by the acceleration of entropy or vorticity perturbations through a nozzle is of interest both as an additional source of transmitted noise, but also as a source of combustion instabilities via backward propagating waves. There is a lack of experimental data, mostly due to difficulties in separating direct and indirect noise. Previous experiments attempted to isolate in...

Information on the distance to the target is very important to achieve the practical use of hands-free speech interfaces and nursing-care robots. Many distance measurement methods, which use the time-of-flight (TOF) of a reflected wave measured with reference to the transmitted wave, have been proposed. However, these methods cannot measure short distances because the transmitted wave, which ha...

BACKGROUND Sexually transmitted infections (STIs) are ongoing concerns. The best method for preventing the transmission of these infections is the correct and consistent use of condoms. Few studies have explored the use of games in interventions for increasing condom use by challenging the false sense of security associated with judging the presence of an STI based on attractiveness. OBJECTIV...

Excessive noise pollution is often a problem for neonatal nurseries. Noise involves not only but also vibrations. The main difference between them that can be heard, and vibrations are felt. human ear cannot detect waves outside the range of 20 Hz–20 KHz. Waves from 0 Hz to 80–100 should considered Both transmitted neonate through incubator’s operational mechanisms other sources. Neonatal units...

We study the inverse problem of recovery a compactly supported non-linearity in semilinear wave equation $$u_{tt}-\Delta u+ \alpha (x) |u|^2u=0$$ , two and three dimensions. probe medium with complex-valued harmonic waves wavelength h amplitude $$h^{-1/2}$$ then they propagate weakly non-linear regime; measure transmitted when it exits $${{\,\mathrm{supp}\,}}\alpha $$ . show that one can extrac...

An ultrasonic reflectivity method is proposed for measuring porosity and tortuosity of porous materials having a rigid frame. Porosity is the relative fraction by volume of the air contained within a material. Tortuosity is a geometrical parameter which intervenes in the description of the inertial effects between the fluid filled the porous material and its structure at high frequency range. I...

A monochromatic beam of wavelength λ transmitted through a periodic one-dimensional diffraction grating with lattice constant d will be spatially refocused at distances from the grating that are integer multiples of . This self-refocusing phenomena, commonly referred to as the Talbot effect, has been experimentally demonstrated in a variety of systems ranging from optical to matter waves. Theor...

The transformation of a weakly nonlinear interfacial solitary wave in an ideal twolayer flow over a step is studied. In the vicinity of the step the wave transformation is described in the framework of the linear theory of long interfacial waves, and the coefficients of wave reflection and transmission are calculated. A strong transformation arises for propagation into shallower water, but a we...