Semi-Supervised Sound Source Localization Based on Manifold Regularization

Conventional speaker localization algorithms, based merely on the received microphone signals, are often sensitive to adverse conditions, such as: high reverberation or low signal to noise ratio (SNR). In some scenarios, e.g. in meeting rooms or cars, it can be assumed that the source position is confined to a predefined area, and the acoustic parameters of the environment are approximately fixed. Such scenarios give rise to the assumption that the acoustic samples from the region of interest have a distinct geometrical structure. In this paper, we show that the high dimensional acoustic samples indeed lie on a low dimensional manifold and can be embedded into a low dimensional space. Motivated by this result, we propose a semi-supervised source localization algorithm which recovers the inverse mapping between the acoustic samples and their corresponding locations. The idea is to use an optimization framework based on manifold regularization, that involves smoothness constraints of possible solutions with respect to the manifold. The proposed algorithm, termed Manifold Regularization for Localization (MRL), is implemented in an adaptive manner. The initialization is conducted with only few labelled samples attached with their respective source locations, and then the system is gradually adapted as new unlabelled samples (with unknown source locations) are received. Experimental results show superior localization performance when compared with a recently presented algorithm based on a manifold learning approach and with the generalized cross-correlation (GCC) algorithm as a baseline

F0 and duration changes in unstressed vs. stressed syllables connected to postlexical stress and sentence type in Standard Lithuanian

This paper presents an analysis of F0 and duration changes in unstressed vs. stressed syllables con­nected to the postlexical stress and sentence type in Lithuanian. The aim of this analysis is to provide a systematic investigation on Lithuanian lexical stress by examining the F0 and duration differences between stressed and unstressed syllables in different sentence types and postlexical stress positions. The material consists of 540 audio-recorded phrases read by two Standard Lithuanian speakers – a male and a female. The results show that F0 does not consistently mark lexical stress in these two speakers’ data and it rather serves postlexical purposes. Significant differences between lexically stressed and unstressed syllables were found only in exclamations and questions when the target word was post­lexically stressed. Duration was found to be the marker of both lexical and postlexical stress. However, with regard to syllable duration, exclamations behave differently from both questions and statements

Velocity correlations in granular materials

A system of inelastic hard disks in a thin pipe capped by hot walls is studied with the aim of investigating velocity correlations between particles. Two effects lead to such correlations: inelastic collisions help to build localized correlations, while momentum conservation and diffusion produce long ranged correlations. In the quasi-elastic limit, the velocity correlation is weak, but it is still important since it is of the same order as the deviation from uniformity. For system with stronger inelasticity, the pipe contains a clump of particles in highly correlated motion. A theory with empirical parameters is developed. This theory is composed of equations similar to the usual hydrodynamic laws of conservation of particles, energy, and momentum. Numerical results show that the theory describes the dynamics satisfactorily in the quasi-elastic limit, however only qualitatively for stronger inelasticity.Comment: 12 pages (REVTeX), 15 figures (Postscript). submitted to Phys. Rev.

Notes on Smooth and Singular Volumetric Growth

The material structure of bodies undergoing growth is considered. In the geometric framework of a general differential manifold modeling the physical space and a fiber bundle modeling spacetime, body points may be defined for any extensive property for which a smooth flux field exists, even if the property is not conserved. Singular flux fields are considered using the notion of a de Rham current. Writing a generalized balance law using the boundary of the current corresponding to a singular flux field, surface growth is unified with volumetric growth.Comment: 5 figure

Use of the sampled electrical engineering device at diagnosing elements in electric systems

Stages of diagnosing procedures of the electric system elements have been introduced. The specialized mathematical device - sampled electrical engineering is developed for work with massifs of instant values of currents and voltages obtained by digital registrars of electric signals. The key rules and procedures of the sampled electrical engineering device are given