Performance of voice and video conferencing over ATM and gigabit ethernet backbone networks

Gigabit Ethernet and ATM network technologies have been modeled as campus network backbones for the simulation-based comparison of their performance. Real-time voice and video conferencing traffic is used to compare the performance of both backbone technologies in terms of response times and packet end-to-end delays. Simulation results show that Gigabit Ethernet has been able to perform the same and in some cases better than ATM as a backbone network for video and voice conferencing providing network designers with a cheaper solution to meet the growing needs of bandwidth-hungry applications in a campus environment

A COMPARATIVE STUDY OF EMPIRICAL FORMULAE FOR ESTIMATING VOWEL-FORMANT BANDWIDTHS

ABSTRACT: The problem of estimating formant bandwidths (B1, B2, B3, etc.) for spoken vowels, under closed-glottis conditions, has in previous studies been approached in two major ways: one accommodates properties of the vocal tract, and the other is driven by curve fitting of measured data. This paper describes quantitative results obtained from a comparative investigation of selected formulae, which are representative of these two approaches. The accuracy of each formula is assessed using bandwidths measured b

Res. Lett. Inf. Math. Sci., 2005, Vol. 7, pp 19-27 19 Available online at http://iims.massey.ac.nz/research/letters/

this paper is to compare the performance of ATM and Gigabit Ethernet technologies employed as high speed high band-width backbone networks deployed for multimedia communications especially with real time voice and video conferencing application

Forensic speaker analysis and identification by computer : a Bayesian approach anchored in the cepstral domain

This thesis advances understanding of the forensic value of the automatic speech parameters by addressing the following question: what is the potentiality of the speech cepstrum as a forensic-acoustic parameter?Despite many advances in automatic speech and speaker recognition, robust and unconstrained progress in technical forensic speaker identification has been partly impeded by our incomplete understanding of the interaction and relation between forensic phonetics and the techniques employed in state-of-the-art automatic speech and speaker recognition. The posed question underlies the recurrent and longstanding issue of acoustic parameterisation in the area of forensic phonetics, where 1) speakeridentification often must be carried out under less than optimal conditions, and 2) views differ on the usefulness and trustworthiness of the formant frequency measurements.To this end, a new formulation for the forensic evaluation of speech data was derived which is effectively a spectral likelihood ratio with enhanced sensitivity to the local peaks of the formant structure of the speech spectrum of vowel sounds, while retaining the characteristics of the Bayesian framework. This new hybrid formula was used together with a novel approach, which is founded on a statistically-based matched-pairs technique to account for various levels of variation inherent in speech recordings, thereby providing a spectrally meaningful measure of variations between two speech spectra and hence the true worth of speech samples as forensic evidence. The experimental results are obtained based on a forensically-realistic database of a relatively large population of 297 native speakers of Japanese.In sum, the research conducted in this thesis is a major step forward in advancing the forensic-phonetic field which broadens the objective basis of the forensic speaker identification. Beyond advancing knowledge in the field, the semi data-independent nature of the new formula ultimately has great implications in technical forensic speaker identification. It also provides us with a valuable biometric tool with both academic and commercial potential in crime investigation in a field which is already suffering from the lack of adequate data