The paper presents the problem of signal degradation in packet-based voice transmission and its influence on the voice recognition correctness. The Internet is evolving into universal communication network which carries all types of traffic including data, video and voice. Among them the Internet telephony, namely VoIP is going to be an application of a great importance and that is why it is so...

This paper considers the statistical properties of the waves generated by a point source in the subsurface and transmitted towards the surface through a randomly layered medium. The problem is analyzed in a regime of separation of scales and with pressure release boundary conditions at the surface. Using a probabilistic representation of the spectral density of the waves received at the surface...

Wave scattering by many (M = M(a)) small bodies, at the boundary of which transmission boundary conditions are imposed, is studied. Smallness of the bodies means that ka << 1, where a is the characteristic dimension of the body and k = 2π λ is the wave number in the medium in which small bodies are embedded. Explicit asymptotic formulas are derived for the field scattered by a single small scat...

We present an iterative nonoverlapping domain decomposition method with second-order Robin-type transmission conditions for the scalar Helmholtz equation in two dimensions. The analysis of the proposed method parallels that for the traditional Robin-type transmission conditions. The new method requires no additional computational complexity and exhibit a more rapid convergence to the exact solu...

We discuss the properties of a large number N of one-dimensional (bounded) locally periodic potential barriers in a finite interval. We show that the transmission coefficient, the scattering cross section σ, and the resonances of σ depend sensitively upon the ratio of the total spacing to the total barrier width. We also show that a time dependent wave packet passing through the system of poten...

We discuss the properties of a large number N of one-dimensional (bounded) locally periodic potential barriers in a finite interval. We show that the transmission coefficient, the scattering cross section σ, and the resonances of σ depend sensitively upon the ratio of the total spacing to the total barrier width. We also show that a time dependent wave packet passing through the system of poten...

In a quantum theory of gravity, fluctuations about the vacuummay be considered as Planck scale virtual black holes appearing and annihilating in pairs. Incident fields scattering from such fluctuations would lose quantum coherence. In a recent paper Hawking & Ross obtained an estimate for the magnitude of this loss in the case of a scalar field. Their calculation exploited the separability of t...

AIM To describe a novel neural network based oral precancer (oral submucous fibrosis; OSF) stage detection method. METHOD The wavelet coefficients of transmission electron microscopy images of collagen fibres from normal oral submucosa and OSF tissues were used to choose the feature vector which, in turn, was used to train the artificial neural network. RESULTS The trained network was able ...