AN EFFICIENT SPEECH GENERATIVE MODEL BASED ON DETERMINISTIC/STOCHASTIC SEPARATION OF SPECTRAL ENVELOPES

The paper presents a speech generative model that provides an efficient way of generating speech waveform from its amplitude spectral envelopes. The model is based on hybrid speech representation that includes deterministic (harmonic) and stochastic (noise) components. The main idea behind the approach originates from the fact that speech signal has a determined spectral structure that is statistically bound with deterministic/stochastic energy distribution in the spectrum. The performance of the model is evaluated using an experimental low-bitrate wide-band speech coder. The quality of reconstructed speech is evaluated using objective and subjective methods. Two objective quality characteristics were calculated: Modified Bark Spectral Distortion (MBSD) and Perceptual Evaluation of Speech Quality (PESQ). Narrow-band and wide-band versions of the proposed solution were compared with MELP (Mixed Excitation Linear Prediction) speech coder and AMR (Adaptive Multi-Rate) speech coder, respectively. The speech base of two female and two male speakers were used for testing. The performed tests show that overall performance of the proposed approach is speaker-dependent and it is better for male voices. Supposedly, this difference indicates the influence of pitch highness on separation accuracy. In that way, using the proposed approach in experimental speech compression system provides decent MBSD values and comparable PESQ values with AMR speech coder at 6,6 kbit/s. Additional subjective listening testsdemonstrate that the implemented coding system retains phonetic content and speaker’s identity. It proves consistency of the proposed approach.The paper presents a speech generative model that provides an efficient way of generating speech waveform from its amplitude spectral envelopes. The model is based on hybrid speech representation that includes deterministic (harmonic) and stochastic (noise) components. The main idea behind the approach originates from the fact that speech signal has a determined spectral structure that is statistically bound with deterministic/stochastic energy distribution in the spectrum. The performance of the model is evaluated using an experimental low-bitrate wide-band speech coder. The quality of reconstructed speech is evaluated using objective and subjective methods. Two objective quality characteristics were calculated: Modified Bark Spectral Distortion (MBSD) and Perceptual Evaluation of Speech Quality (PESQ). Narrow-band and wide-band versions of the proposed solution were compared with MELP (Mixed Excitation Linear Prediction) speech coder and AMR (Adaptive Multi-Rate) speech coder, respectively. The speech base of two female and two male speakers were used for testing. The performed tests show that overall performance of the proposed approach is speaker-dependent and it is better for male voices. Supposedly, this difference indicates the influence of pitch highness on separation accuracy. In that way, using the proposed approach in experimental speech compression system provides decent MBSD values and comparable PESQ values with AMR speech coder at 6,6 kbit/s. Additional subjective listening testsdemonstrate that the implemented coding system retains phonetic content and speaker’s identity. It proves consistency of the proposed approach

THE NEED TO STUDY THE BASIS OF COPYRIGHT AND LICENSE BY STUDENTS OF DIRECTIONS RELATED TO THE DEVELOPMENT OF THE SOFTWARE

The article discusses the main reasons for students to study copyright information system software developers and understanding the difference between them.В статье рассматриваются основные причины необходимости изучения студентами разработчиками информационных систем авторское правое в сфере лицензирования программного обеспечения и понимание разницы между ними

Improving the University Digital Infrastructure Management System: Practice of Social Network Analysis

This article presents the results of applied research aimed at developing topical approaches to solving the problem of dysfunctionality of universities’ digital infrastructures in social media. In the context of the large-scale digitalization and networking processes of modern society, higher education institutions are faced with new challenges that threaten their further sustainability and reduce their competitiveness. As a possible solution to this problem, the authors propose a comprehensive study of university network structures in social media and further implementation of actual practices of online profile management and digital communities. By applying the method of social graphs and automated tools for processing open digital data, a universal algorithm for building and interpreting the resulting visual models is defined. The article substantiates the basic problems faced by modern universities in developing their own digital structures, as well as the ways to solve them, aimed at improving digital infrastructure management, establishing effective communication with target groups, consolidating the organizational structure, developing educational and scientific communities, and promoting the university brand. The proposed interactive digital maps have a high practical potential for direct implementation in the management process of the Russian universities

Instantaneous pitch estimation algorithm based on multirate sampling

The paper presents an algorithm for accurate pitch estimation that takes advantage of the sinusoidal model with instantaneous parameters. The algorithm decomposes the signal into subband components, extracts their instantaneous parameters and evaluates period candidate generating function (PCGF). In order to achieve high accuracy for low and high-pitched sounds it is assumed that possible pitch variation range is proportional to current pitch value. The bandwidths of the decomposition filters and length of the analysis frame are scaled for each period candidate by multirate sampling. The algorithm is compared to other widely used pitch extractors on artificial quasiperiodic signals and natural speech. The proposed algorithm shows a remarkable frequency and time resolution for pitch-modulated sounds and performs well both in clean and noisy conditions

Numerical study of the normal current density behaviour in a narrow - gap glow discharge

A numerical study of normal glow discharge properties was performed in the case of small electrodes separations (0.05-0.4 cm) and moderate gas pressures (10-46 Torr). A recently observed new experimental effect of a considerable reduction in the normal current density for smaller discharge lengths was analyzed both by means of 2D fluid model and by a minimal 1D drift model of gas discharge. A good agreement between theoretical and experimental behaviour was demonstrated. An influence of the electrodes separation and of the gas heating on the value of the normal current density is discussed.Comment: 20 pages, 4 figure

Prolonged repolarization in the early phase of ischemia is associated with ventricular fibrillation development in a porcine model

Background: Repolarization prolongation can be the earliest electrophysiological change in ischemia, but its role in arrhythmogenesis is unclear. The aim of the present study was to evaluate the early ischemic action potential duration (APD) prolongation concerning its causes, expression in ECG and association with early ischemic ventricular fibrillation (phase 1A VF).Methods: Coronary occlusion was induced in 18 anesthetized pigs, and standard 12 lead ECG along with epicardial electrograms were recorded. Local activation time (AT), end of repolarization time (RT), and activation-repolarization interval (ARIc) were determined as dV/dt minimum during QRS-complex, dV/dt maximum during T-wave, and rate-corrected RT–AT differences, respectively. Patch-clamp studies were done in enzymatically isolated porcine cardiomyocytes. IK(ATP) activation and Ito1 inhibition were tested as possible causes of the APD change.Results: During the initial period of ischemia, a total of 11 pigs demonstrated maximal ARIc prolongation >10 ms at 1 and/or 2.5 min of occlusion (8 and 6 cases at 1 and 2.5 min, respectively) followed by typical ischemic ARIc shortening. The maximal ARIc across all leads was associated with VF development (OR 1.024 95% CI 1.003–1.046, p = 0.025) and maximal rate-corrected QT interval (QTc) (B 0.562 95% CI 0.346–0.775, p < 0.001) in logistic and linear regression analyses, respectively. Phase 1A VF incidence was associated with maximal QTc at the 2.5 min of occlusion in ROC curve analysis (AUC 0.867, p = 0.028) with optimal cut-off 456 ms (sensitivity 1.00, specificity 0.778). The pigs having maximal QTc at 2.5 min more and less than 450 ms significantly differed in phase 1A VF incidence in Kaplan-Meier analysis (log-rank p = 0.007). In the patch-clamp experiments, 4-aminopyridine did not produce any effects on the APD; however, pinacidil activated IK(ATP) and caused a biphasic change in the APD with initial prolongation and subsequent shortening.Conclusion: The transiently prolonged repolarization during the initial period of acute ischemia was expressed in the prolongation of the maximal QTc interval in the body surface ECG and was associated with phase 1A VF. IK(ATP) activation in the isolated cardiomyocytes reproduced the biphasic repolarization dynamics observed in vivo, which suggests the probable role of IK(ATP) in early ischemic arrhythmogenesis

Overview of convolutional neural networks for image recognition

Цель работы, результаты которой представлены в рамках статьи, заключалась в исследовании современных архитектур сверточных нейронных сетей для распознавания изображений. В статье рассмотрены такие архитектуры как AlexNet, ZFnet, VGGNet, GoogleNet, ResNet. Характеристикой о качестве распознавания изображения для нейронной сети является ошибка top-5. На основе полученных результатов было выявлено, что на данный момент сетью с наиболее точным результатом является свёрточная сеть ResNet с показателем точности в 3,57%. Преимуществом данного исследования является то, что приведенная статья дает краткую характеристику свёрточной нейронной сети, а также дает представление о современных архитектурах свёртчных сетей, их строением и качественными показателями. The purpose of the work, the results of which are presented in the article, was to study modern architectures of convolutional neural networks for image recognition. This article discusses such architectures as AlexNet, ZF net, Get, Google Net, Reset. The characteristic about the image recognition quality for a neural network is the top-5 error. Based on the results obtained, it was found that at the moment the network with the most accurate result is the RESNET convolutional network with an accuracy rate of 3.57%. The advantage of this study is that this article provides a brief description of the convolutional neural network, as well as gives an idea of modern architectures of convolutional networks, their structure and quality indicators

Association between antiarrhythmic, electrophysiological and antioxidative effects of melatonin in ischemia/reperfusion

Melatonin is assumed to confer cardioprotective action via antioxidative properties. We evaluated the association between ventricular tachycardia and/or ventricular fibrillation (VT/VF) incidence, oxidative stress, and myocardial electrophysiological parameters in experimental ischemia/reperfusion under melatonin treatment. Melatonin was given to 28 rats (10 mg/kg/day, orally, for 7 days) and 13 animals received placebo. In the anesthetized animals, coronary occlusion was induced for 5 min followed by reperfusion with recording of unipolar electrograms from ventricular epicardium with a 64-lead array. Effects of melatonin on transmembrane potentials were studied in ventricular preparations of 7 rats in normal and ?ischemic? conditions. Melatonin treatment was associated with lower VT/VF incidence at reperfusion, shorter baseline activation times (ATs), and activation-repolarization intervals and more complete recovery of repolarization times (RTs) at reperfusion (less baseline-reperfusion difference, ΔRT) (p < 0.05). Superoxide dismutase (SOD) activity was higher in the treated animals and associated with ΔRT (p = 0.001), whereas VT/VF incidence was associated with baseline ATs (p = 0.020). In vitro, melatonin led to a more complete restoration of action potential durations and resting membrane potentials at reoxygenation (p < 0.05). Thus, the antioxidative properties of melatonin were associated with its influence on repolarization duration, whereas the melatonin-related antiarrhythmic effect was associated with its oxidative stress-independent action on ventricular activation.Fil: Sedova, Ksenia A.. Czech Technical University In Prague; República ChecaFil: Bernikova, Olesya G.. Ural Branch of Russian Academy of Sciences; RusiaFil: Cuprova, Julia I.. Czech Technical University In Prague; República ChecaFil: Ivanova, Alexandra D.. Lomonosov Moscow State University; RusiaFil: Kutaeva, Galina A.. Pitirim Sorokin Syktyvkar State University; RusiaFil: Pliss, Michael G.. Almazov National Medical Research Centre; RusiaFil: Lopatina, Ekaterina V.. University of Saint Petersburg; RusiaFil: Vaykshnorayte, Marina A.. Ural Branch Of Russian Academy Of Sciences; RusiaFil: Diez, Emiliano Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Medicas. Instituto de Fisiologia; ArgentinaFil: Azarov, Jan E.. Ural Branch of Russian Academy of Sciences; Rusia. Pitirim Sorokin Syktyvkar State University; Rusi

АЛГОРИТМ ПОДАВЛЕНИЯ ШУМА И АКУСТИЧЕСКОЙ ОБРАТНОЙ СВЯЗИ НА ОСНОВЕ СПЕКТРАЛЬНОГО ВЫЧИТАНИЯ В СЛУХОВОМ ПРОТЕЗЕ НА БАЗЕ СМАРТФОНА

The paper presents a combined noise and acoustic feedback reduction algorithm. The algorithm is based on spectral subtraction and is robust to rapid changes in acoustic feedback path which makes it suitable for using in a smartphone-based hearing aid.В работе предлагается совмещенный алгоритм подавления шума и акустической обратной связи. Алгоритм основан на спектральном вычитании и является устойчивым к резким изменениям параметров пути распространения акустической обратной связи, что делает его подходящим для использования в слуховых протезах на основе смартфонов

Научная школа профессора А. А. Петровского

Two periods of scientific activity of Professor Alexander Alexandrovich Petrovsky, who was a member of the editorial board of the journal "Informatics" for 15 years (2004–2019), are presented. The main scientific results, his contribution to the development of the theory and to the hardware and software of the problem-oriented real-time systems and the processing of audio, speech and graphic information are shown, a list of the most significant works of the scientist is given.Представлены два периода научной деятельности профессора Александра Александровича Петровского, который на протяжении 15 лет (2004–2019) являлся членом редакционной коллегии журнала «Информатика». Показаны основные научные результаты, его вклад в области разработки теории и аппаратно-программных средств проблемно-ориентированных систем реального времени и обработки звуковой, речевой, графической информации, приведен перечень наиболее значимых трудов ученого