INFLUENCE OF SPECIFIC VOIP TRANSMISSION CONDITIONS ON SPEAKER RECOGNITION PROBLEM

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 important to assess how specific conditions and distortions of the Internet transmission (speech coding and most of all packet loss and delay) can influence speaker recognition problem. The Gaussian Mixture Models classification, the feature extraction, the Internet speech transmission standards and the signal degradation methodology applied in the tested system were overviewed. The experiments carried out for two most commonly applied encoders (G.711 and G.723) and three network conditions (poor, average and with no packet loss) revealed a minor significance of the packet loss problem in the tested text-independent system

INFLUENCE OF SPECIFIC VOIP TRANSMISSION CONDITIONS ON SPEAKER RECOGNITION PROBLEM

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 important to assess how specific conditions and distortions of the Internet transmission (speech coding and most of all packet loss and delay) can influence speaker recognition problem. The Gaussian Mixture Models classification, the feature extraction, the Internet speech transmission standards and the signal degradation methodology applied in the tested system were overviewed. The experiments carried out for two most commonly applied encoders (G.711 and G.723) and three network conditions (poor, average and with no packet loss) revealed a minor significance of the packet loss problem in the tested text-independent system

Effect of short HV pulses on bacteria and fungi

The survival of three kinds of microorganisms under strongpulse electric field conditions was investigated with a possible application of the electric pulse method for sterilization of consumable liquids. The results of the investigations of survival ratio of Gram-negative (Escherichia coli, Yersinia enterocolitica) and Gram-positive (Staphylococcus aureus, Listeria monocytogenes) bacteria and yeastlike fungi (Candida albicans) are presented. The HV pulses with peak voltage U = 0 to 100 kV and rise time t, = 0.5 to 1.2 ps were applied. The microorganisms were suspended in an NaCl solution with 7 = 6 to 13 mS/cm conductivity and pH = 7.2. The experimental setup and the dependency of the microorganism survival ratio on the rise time, peak voltage and on the number of pulses applied, are presented. It has been found that the lethal effect on microorganisms caused by HV pulses depends on the pulse parameters as well as on the kind of microorganism being treated

Inactivation of Yersinia enterocolitica Gram-negative bacteria using high voltage technique

High voltage pulses of peak voltages U=5-75 kV and rise times tp=500-1300 ns were applied with repetition frequency f=lHz in order to cause the irreversible electroporation of Gram negative bacteria Yersinia enterocolitica. The bacteria were suspended in NaCl solution of pH=7.2 and conductivity y ~0.8-1.3 S/m. The suspension was placed in glass tube immersed in the cylindrical electrode system gap filled with distilled water. Such an electrode system will protect the bacteria suspension from the chemical processes at the electrode-liquid interface due to conduction and pre-breakdown phenomena. The current chopping electrode system was connected in parallel to the sample in order to avoid heat generation from direct discharge of the pulse through the suspension. The dependence of the survival ratio s=N/No (the number of bacteria per cm3 after pulse treatment, N, divided by the number of bacteria per cm3 before treatment, NJ of Y. enterocolitica on peak voltage of the pulse, number of pulses applied and on various rise times of pulses have been measured. The reduction by 6 orders of magnitude of Y. enterocolitica living cells per cm3 was achieved. The results show that considerable inactivation of microbes can be achieved by the application of short (tp 4000 ns) high voltage pulses for bacteria suspension without directly exposing the bacteria suspension to the electrodes. It is therefore possible to use the electrode system proposed as a means for sterilization of liquid foods

SpeechDat(E) - Eastern European Telephone Speech Databases

Contains fulltext : 76435.pdf (author's version ) (Open Access)6 p