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In telephone conversations, only short consecutive utterances can be examined for each speaker, therefore, discriminating between speakers in such conversations is a challenging task which becomes even more challenging when no information about the speakers is known a priori. In this paper, a technique for determining the number of speakers participating in(More)
The detection of unvoiced speech in the presence of additive background noise is complicated by the fact that unvoiced speech is very similar to white noise. The mechanism of production of unvoiced speech is known to be due to turbulent airflow in the constrictions of the vocal tract. Three approaches for detecting unvoiced speech from additive background(More)
Two speaker indexing system for conversations are presented in this paper. The first method involves indexing two-speaker conversations. In this method, two reference models are judiciously chosen from the conversation such that they represent the two different speakers. Models are then matched to the reference speakers using distance-based comparisons. The(More)
The accuracy of present day speaker identification systems (SID) is degraded in adverse acoustical environments. The idea of usable speech is to identify and extract those portions of degraded speech which are considered useful for SID. Recently, a usable speech extraction system was proposed to classify cochannel speech as usable speech and unusable speech(More)
The problem of determining the number of speakers participating in a conversation and building their models in short conversations, within an unknown group of speakers, is addressed in this paper. The lack of information about the number of speakers and the unavailability of sufficient data present a challenging task of efficiently estimating the speaker(More)
Unsupervised speaker indexing is a rapidly developing field in speech processing, which involves determining who is speaking when, without having prior knowledge about the speakers being observed. In this research, a distance-based technique for indexing telephone conversations is presented. Sub-models are formed (using data of approximately equal sizes)(More)
The dipole moment of alamethicin, which produces voltage-dependent conductance in lipid-bilayer membranes, was measured in mixed solvents of ethanol and dioxane. The value of the dipole moment was found to increase from 40 to 75 DU (Debye units), as the concentration of ethanol increased from 0 (pure dioxane) to 40%. The relaxation frequency of alamethicin(More)
Changes in the membrane capacity of squid axons during hyper- and depolarizations are measured between --160 and +40 mV. After corrections for the series resistance and fringe effect, we found that the membrane capacity increased from 0.68 to 1.2 muF/cm2 with depolarization. It was further observed that tetrodotoxin the external medium eliminated the change(More)
Recognizing speakers from their voices is a challenging area of research with several practical applications. Presently speaker verification (SV) systems achieve a high level of accuracy under ideal conditions such as, when there is ample data to build speaker models and when speaker verification is performed in the presence of little or no interference. In(More)
A novel approach to performing speaker clustering in telephone conversations is presented in this paper. The method is based on a simple observation that the distance between populations of feature vectors extracted from different speakers is greater than a preset threshold. This observation is incorporated into the clustering problem by the formulation of(More)