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Within the framework of the traditional scope of investigations in the field of acoustic measurements, we consider an autoregressive model of the vocal tract, which is a key link in the speech apparatus of human beings. We mention the existence of an urgent problem of guaranteeing the stability of the autoregressive model in systems with adaptation of their parameters to the observed speech signals of short duration. To overcome this difficulty, we pose the problem of testing the stability of the autoregressive model and adjustment of its parameters according to the results of testing. The required investigations are based on the original authors' technique of the formant analysis of vowel sounds of speech via the synthesis of a recursive shaping filter in the mode of free oscillations. For the solution of the posed problem, we propose a procedure aimed at testing the stability of the autoregressive model of vocal tract and adjustment of its parameters. The method is based on a two-stage algorithm of transformation of the autoregressive model of vocal tract. In the first stage of transformation, the stability of the autoregressive model is checked according to the impulse response of the shaping filter. In the second stage, if the stability of the autoregressive model is violated, its impulse response is modified as a result of the element-by-element multiplication by a variable exponential quantity asymptotically convergent to zero. We develop a regular algorithm for recalculating a modified impulse response into the adjusted vector of autoregressive parameters in the second stage of transformation. According to the results of experimental verification of the proposed method, we make a conclusion that the guaranteed stability of the autoregressive model of the vocal tract is attained with minimal distortions in the frequency domain. The obtained results can be useful for the development and improvement of the systems of automatic speech recognition, digital speech communications, artificial intelligence, and other information systems based on the use of data compression and speech encoding according to the autoregressive model of the vocal tract in the course of automatic processing of speech signals. [ABSTRACT FROM AUTHOR]

The aim of this review is to summarize and comparatively analyze recent reports on studying carbon dioxide conversion to methanol, dimethyl ether, and C2+ hydrocarbons, in particular, olefins, by catalytic hydrogenation. It is shown that the main approaches to providing high activity and selectivity of these processes are the targeted design of catalysts and the selection of conditions for hydrogenation processes, in particular, the use of supercritical CO2 and procedures that are alternative to conventional physicochemical methods for CO2 activation (electrocatalysis, photocatalysis). [ABSTRACT FROM AUTHOR]

This research relates to the field of speech technologies, where the key issue is the optimization of speech signal processing under conditions of a prior uncertainty of its fine structure. The problem of automatic (objective) analysis of the speaker's voice timbre using a speech signal of finite duration is considered. It is proposed to use a universal information-theoretic approach to solve it. Based on the Kullback-Leibler divergence, an expression was obtained to describe the asymptotically optimal decision statistic for differentiating speech signals by the voice timbre. The author highlights a serious obstacle during practical implementation of such statistics, namely: synchronization of the sequence of observations with the pitch of speech signals. To overcome the described obstacle, an objective measure of timbre-based differences in speech signals is proposed in terms of the acoustic theory of speech production and its "acoustic tube" type model of the speaker's vocal tract. The possibilities of practical implementation of a new measure based on an adaptive recursive filter are considered. A full-scale experiment was set up and carried out. The experimental results confirmed two main properties of the proposed measure: high sensitivity to differences in speech signals in terms of voice timbre and invariance with respect to the fundamental pitch frequency. The obtained results can be used when designing and studying digital speech processing systems tuned to the speaker's voice, for example, digital voice communication systems, biometric and biomedical systems, etc. [ABSTRACT FROM AUTHOR]

The problem statement is given and the algorithm for solving problems of plasticity for axisymmetric bodies made of isotropic materials with properties depending on a stress mode and plastic loosening is described. The constitutive equations of the theory of deformation processes along the trajectories of small curvature containing two nonlinear dependences are used. One of them implements the relationship between the first invariants of stress and strain tensors, and the other one implements the relationship between the second invariants of the corresponding deviators. The effect of the dependence of deformation curves on the stress mode and the plastic change in the bulk strain on the results of calculating the stress-strain state of the shell is studied. [ABSTRACT FROM AUTHOR]

The paper reports the results of a kinetic and thermodynamic analysis of non-catalytic partial oxidation of methane and C2–C4 hydrocarbon/hydrogen mixtures (C/H = 1 : 4) at 1400–1700 K. The hydrocarbon conversion sequence and the time periods of the major process stages were identified for isothermal conditions. The initial stage of the oxidative conversion of C2+ hydrocarbons consists of their pyrolysis, primarily into ethylene and propylene, followed by oxidation of the pyrolysis products. In this respect, the kinetics of C2+ hydrocarbon oxidative conversion are different from those of methane conversion, marked by the almost simultaneous and significantly slower occurrence of pyrolysis and oxidation. The subsequent stages involve steam and dry reforming of the oxidation products, namely acetylene and methane; these stages continue until the main products (H2, CO, CO2, and H2O) reach an equilibrium distribution for the given temperature. The study findings are important for the optimization of various techniques for high-temperature syngas production via partial oxidation of C2+ hydrocarbons, as well as Moderate or Intense Low-Oxygen Dilution (MILD) combustion processes. [ABSTRACT FROM AUTHOR]

Reducing carbon dioxide emissions during production is one of the main trends in modern oil and gas chemistry. One of the most realistic possibilities for achieving this is to involve carbon dioxide generated in technological processes as a feedstock for producing gas chemical products. The maximum effect can be achieved in the production of large-scale chemicals, such as syngas, hydrogen, and methanol. We consider such possibilities and present a new combined autothermal process for the joint production of hydrogen and methanol based on non-catalytic matrix conversion of natural gas into syngas, which allows one to almost avoid CO2 emissions. [ABSTRACT FROM AUTHOR]

The task of comparison testing of time series power spectrum parametric estimates is considered. It is shown that an urgent problem that arises in solving it is the optimization of the parameters of spectral estimates under conditions of small samples of observations. To overcome this problem, it is proposed to use the system-wide concept of analysis through time series synthesis. Based on this concept, a regular method was developed for comparison testing of parametric estimates of the power spectrum that are obtained from a time series of finite duration. Within the method, solutions are accepted based on the results of testing statistical hypotheses about the homogeneity of two samples: the finite empirical one, compiled based on the results of observations, and an infinite virtual one, mathematically synthesized according to each individual parametric estimate in the series of spectral alternatives being examined. The principle of minimum informational divergence between samples according to the Kullback–Leibler criterion. An example of the practical application of the developed method is presented in the problem of discrete spectral modeling of speech signals. The ability of the method to identify patterns of unstable parametric estimates of the autoregressive type has been shown. The results obtained are intended for use in the field of speech acoustics, as well as technical and medical diagnostics, where parametric methods of spectral analysis are increasingly used in practice. [ABSTRACT FROM AUTHOR]

A technique to improve the convergence of the process of successive approximations in boundary-value problems of thermoviscoplasticity is proposed. The constitutive equations of the theory of simple processes and the theory of processes of deformation along small-curvature paths are used. It is assumed that the specific works of deformation of elementary volumes of the specimen and the body at certain values of the intensity of tangential stresses and shear strains are equal. A number of approximations in test problems of the shell theory and in a spatial problem under nonaxisymmetric loading are considered. It is shown that the proposed modification of the process of successive approximations halves their number. [ABSTRACT FROM AUTHOR]

Starting from the definition of the main tone of the speaker's speech as the minimum frequency of the linear power spectrum of the vocalized segments of the speech signal, an estimation of potentially achievable accuracy of its measurement under the action of background interference such as white Gaussian noise has been made. Based on this estimation, a suboptimal algorithm for measuring the pitch frequency using a short speech frame has been developed. The developed algorithm effectiveness is confirmed by the results of the experiment, during which the author's software was used. [ABSTRACT FROM AUTHOR]

The task of measuring the spectral density of power of a speech signal in sliding observation window mode is examined. A parametric approach to solving this task using an autoregressive data model is studied. The problem of optimizing the order of an autoregressive model under the conditions of small samples is studied. It is proposed to solve the problem using a hybrid method of spectral analysis based on sequential enumeration of a finite number of variants. The optimization criterion is formulated in terms of an inverse problem: from the speech signal to the voice source. It uses the scale-invariant measure of the spectral distance as the objective function, and the Schuster periodogram as the reference sample. The effectiveness of the hybrid method has been experimentally evaluated on the basis of the author's software. It is shown that with the duration of the observation window no greater than 10 ms, the use of the hybrid method increases the accuracy of spectral analysis by more than 30%, compared to the well-known Berg method, the order of which is established according to the Akaike information criterion. [ABSTRACT FROM AUTHOR]

The problem of the spectral analysis of speech signals in automatic speech recognition systems is considered within the framework of a dynamically developed direction of investigations in the field of acoustic measurements. We indicate that efficiency of the analyzed systems under unfavorable conditions of speech production (noise and insufficient intelligibility of speech sounds) is low as compared with human perception of oral speech. To improve the efficiency of automatic speech recognition systems, we propose to use a two-stage algorithm of spectral analysis of the speech signals. The first stage of processing of speech signals is their parametric spectral analysis performed by using an autoregressive model of the vocal tract of a conventional speaker. The second stage of processing is the transformation (modification) of the obtained spectral estimate according to the principle of frequency-selective amplification of the amplitude of main formants of the intraperiod power spectrum. The software implementation of the proposed algorithm is described on the basis of the computational procedure of fast Fourier transform. By using the software developed by the authors, we performed full-scale experiments and studied an additive mixture of vowel sounds in the speech of a control speaker with white Gaussian noise. The obtained experimental results enable us to conclude that the amplitudes of the main formants of speech signals are amplified by 10–20 dB and, hence, the intelligibility of speech sounds substantially improves. The developed algorithm can be used in the automatic speech recognition systems based on processing of the speech signals in the frequency domain, including the use of artificial neural networks. [ABSTRACT FROM AUTHOR]

The problem of autoregressive modeling of a speech signal based on the data of the discrete Fourier transform in the mode of a sliding window of small duration (milliseconds) is considered. The problem of stability of the formed autoregressive model is investigated. To overcome it, it is proposed to use the envelope of the Schuster periodogram as a reference spectral sample. A new method of autoregressive modeling has been developed, in which the detection of the spectral envelope is carried out using a recirculator of a sequence of samples in the frequency domain. An example of its practical implementation is considered, a full-scale experiment is set up and carried out. Based on the results of the experiment, conclusions were drawn about achieving a significant gain in terms of not only stability, but also the accuracy of the autoregressive model of the speech signal. [ABSTRACT FROM AUTHOR]

The problem of determining the accuracy of an autoregressive model of a speech signal is considered, and a method for measuring the accuracy index in the sliding observation window mode is proposed. As an indicator of accuracy, we used a modified value of the COSH-distance (hyperbolic cosine) of the autoregressive model relative to the eponymous (single phoneme) Schuster periodogram as a reference spectral sample. To study the possibilities of the proposed method, a full-scale experiment was set up and carried out, in which the object of study was a set of autoregressive models of different orders. These models were obtained by Berg's method for the vowel speech sounds of a test speaker. According to the results of the performed measurements for each vowel, the optimal values of the autoregressive order and the corresponding optimal autoregressive model were found. It is shown that this optimization made it possible to increase the accuracy of the autoregressive model of the speech signal by more than 60%, depending on the sound of the test speaker's speech and the characteristics of his vocal tract. The results obtained are intended for use in automatic processing and digital speech transmission systems with radical data compression based on linear prediction coefficients. [ABSTRACT FROM AUTHOR]

This paper describes the results of calculations using the density functional method to determine the parameters governing charge transfer rates in stacks composed of "donor (D)–π-bridge–acceptor (A)–π-bridge–donor (D)" molecules. The Marcus theory is employed to calculate the reorganization energy, which is a property of individual molecules, and the charge transfer integral, which is calculated for molecular dimers. Another important structural property of the molecules is the side substituent of the acceptor block, that is, short linear or branched alkyl chains. These can influence the reorganization energy values and the morphology of the film, which, in turn, impacts the charge transfer integral. Finally, the Einstein–Smoluchowski formula is used to determine the electron and hole mobility for transport along the stacking direction. The calculated values are then compared to experimental data found in the literature for polymers with similar monomer units that only differ in the length of their acceptor block substituent. [ABSTRACT FROM AUTHOR]

A method of numerical analysis of temperature fields and thermoelastoplastic stress–strain state of thin shells with assessment of strength under repeated loading is proposed. The modified constitutive equations of the theory of deformation along paths of small curvature are used, taking into account the perfect Bauschinger effect. A numerical example is given. [ABSTRACT FROM AUTHOR]

Results are presented from studying the temperature dependences of the characteristic intensity of NMR signals and period T1 of relaxation on protons and nuclei of sodium in mixed aqueous solutions of sodium chloride with additions of salts of CaCl2, KCl, MgCl2, and MgSO4 of different concentrations. Effects of ion hydration in the freezing of mixed solutions are shown. The eutectic point of NaCl does not shift in the presence of other salts, period T1 of relaxation on protons experiences a sharp jump in the region of the NaCl eutectic point, and T1 changes only slightly on sodium nuclei. [ABSTRACT FROM AUTHOR]

The problem of determining a fundamental tone frequency of a speech signal in the presence of white Gaussian noise is examined. A method for measuring this frequency is proposed which takes into account the periodic structure of the power spectrum of voiced speech frames and is based on the principle of harmonic energy accumulation in the frequency domain. For this purpose a procedure for equalizing the envelope of the power spectrum is introduced in the algorithm for processing a speech signal using a two-level autoregression model of the observations: within the limits of a single period of the fundamental tone and within an interval of several of these periods. Here adaptation of the order of the autoregression of the lower level to the observed frame is planned. An example of the practical realization of the adaptive method based on the Berg method is examined. The basic advantages of the adaptive method compared to the known analogs are high speed and enhanced noise stability, which are confirmed in a full-scale experiment. A gain in threshold signals of 5-10 dB was obtained through use of the adaptive method. [ABSTRACT FROM AUTHOR]

The development of noncatalytic procedures for processing hydrocarbon gases is an important way to increase the efficiency of gas-chemical processes and decrease their power consumption. The paper deals with thermodynamic and kinetic modeling of noncatalytic processes of the partial oxidation and steam and carbon dioxide conversion of methane in the temperature interval 1400–1800 K and with analysis of the process for syngas production by matrix conversion of rich methane–oxygen mixtures. Comparison of the kinetic calculations with the experimental data demonstrated the possibility of applying published models to the description of the matrix conversion of methane. The possibility of developing a highly efficient technology based on noncatalytic partial oxidation of hydrocarbons for the syngas production without СО2 emission into the environment is discussed. [ABSTRACT FROM AUTHOR]

The reaction of sodium ricinoleate with thiophosphoryl trichloride under various conditions was studied. At a high concentration of sodium ricinoleate, thiophosphoryl trichloride reacts primarily with the alcohol OH group, and the isolated compound contains a sodium acyl group, which was confirmed by IR, 1H, 13C, 31P NMR spectroscopy and elemental analysis data. When the salt solution is diluted 5 times, the reaction proceeds by the mechanism of nucleophilic substitution both on the carboxylate and on the alcohol group. According to gel chromatography data, the molecular weight of the reaction product is close to trisubstituted thiophosphate, the composition and structure of which are confirmed by elemental analysis and IR, 1Н, 13С, 31Р NMR spectroscopy and diffractometry data. During chromatography on silica gel, it decomposes, as during hydrolysis in a slightly acidic medium. [ABSTRACT FROM AUTHOR]

The interaction of two types of modality of a system for processing audiovisual information in the problem of evaluating the emotional state of users of dialogue information systems was studied. In order to enhance the precision of an estimation in real time, it is proposed to use an audio modality for the purpose of detecting speech segments of increased emotionality. As an indicator of the degree of speech emotionality, the intensity of the flow of vowel sounds in a user's speech signal at input to the information system is used. A method has been developed for measuring this indicator from the empirical probability of the occurrence of vowel sounds in the user's a speech signal. An example is presented for practical implementation of the method in soft real time. A full-scale experiment using the authors' software was posed and presented. The advantages of the proposed method are shown: high speed of operation and high sensitivity to the change in the level of speech emotionality of users. Results obtained are intended for developers of advanced information systems with an audiovisual user interface. [ABSTRACT FROM AUTHOR]

Two types of constitutive equations accounting for the stress mode and the loosening of the material during elastoplastic deformation are considered. The constitutive equations of one type include two nonlinear relationships between the first invariants of the stress and strain tensors and between the second invariants of the deviator tensors and include the third invariant of the stress deviator. The constitutive equations of the other type use equivalence stress containing the first and second invariants of the stress tensor. Literature experimental data for tubular isotropic specimens under tension, compression, torsion, and internal pressure are used for assessing the loosening of the material. [ABSTRACT FROM AUTHOR]

Multipotent mesenchymal stromal cells (MSC) were administered to patients after allogeneic hematopoietic stem cell transplantation to prevent the development of acute graft—versus— host disease (GVHD). The injection of MSC did not always prevent the development of GVHD. The aim of the work was to compare the secretome of MSC effective and ineffective in the prevention of GVHD. MSC were obtained from the bone marrow of hematopoietic stem cells donors. The secretome was studied using a TripleTOF 5600+ mass spectrometer with a NanoSpray III ion source coupled to a NanoLC Ultra 2D Plus nano-HPLC System. A total of 1,965 proteins were analyzed. Analysis of the secretome of effective and ineffective MSC samples revealed significant differences in the secretion of 1,119 proteins associated with ribosomes, exosomes, focal contacts, and others. Analysis of proteins secreted by MSC can be used to identify prognostically effective samples. [ABSTRACT FROM AUTHOR]

The kinetic patterns of the attainment of the equilibrium product composition in non-catalytic processes of partial oxidation and of steam and carbon dioxide reforming of hydrocarbons in the temperature range 1400–1800 K, characteristic of these processes, were analyzed. The need for such analysis is caused by the rapidly increasing consumption of natural gas as a chemical feedstock and by growing attention to environmental problems, in particular, to a decrease in СО2 emissions or to partial CO2 utilization. The forward and reverse water gas shift reactions (WGSRs) play an important role in approach to the equilibrium product composition in these processes. Analysis has shown that the elementary reactions characteristic of forward and reverse WGSRs start to play a significant role long before the equilibrium in the system is attained. Already in the intermediate steps of the process, the distribution of the major reaction products, Н2, СО, Н2О, and СО2, almost corresponds to the equilibrium value of Kt = ([H2][CO2])/([CO][H2O]), close to the WGSR equilibrium constant Keq, and further conversion of the products occurs at Kt values close to Keq. [ABSTRACT FROM AUTHOR]

A study on the growing importance of gas chemistry to the world economy and the resulting need to create new catalytic and non-catalytic technologies for converting natural gas and other hydrocarbon gases into chemical products is performed. Existing and promising non-catalytic processes of converting them into synthesis gas are discussed, along with direct ways of obtaining chemical products from methane, the main component of natural gas. [ABSTRACT FROM AUTHOR]

The article proposes a new algorithm for solving the problem of real-time detection of vowel speech sounds based on (R + 1)-element information and the whitening filter method. An example of practical application of the algorithm is described and an assessment of its efficiency is provided. A full-scale experiment is conducted; its results indicate that the proposed algorithm demonstrates a sufficiently high speed and a guaranteed significance level of decisions with minimal performance requirements to the computing equipment. [ABSTRACT FROM AUTHOR]

The article considers the problem of personal biometric data "aging" over time. A method has been proposed to overcome this problem by automatically updating the specified data in the biometric system storage using the speech signals of registered users obtained during latest requests for their identification and online service. The proposed method uses a scale-invariant indicator of the voice template quality. As a result, it is characterized by guaranteed reliability of the decisions made in the conditions of a wide speech signal dynamic range. It was established that the use of a scale-invariant indicator provides the guaranteed significance level of decisions made by a conventional observer. A full-scale experiment implementing the proposed method has been set up and carried out using an authoring software; practical justification for the effectiveness of the proposed method with real speech data has been given. The results obtained are intended for using in the development of new and modernization of existing systems and technologies for automated quality control and updating of personal biometric data. [ABSTRACT FROM AUTHOR]

In this paper it is considered the problem of reduction or reduction of the order p ≫ 1 of an autoregressive model (AR-model) of a speech signal by the criterion of minimum loss of useful information. The problem is formulated as an optimization problem in terms of discrete spectral modeling. It is indicated that the most acute problem in solving is the necessity to scale the AR-model parameters for the simulated signal at each step of iterative calculation process. To overcome this problem, it is proposed to use the measure of information divergence of signals in the frequency domain with the property of scale invariance as the goal functional. On its basis, a new method of the AR-model reduction is developed where the scaling operation exceeds the limits of the iterative optimization procedure. The effectiveness of the proposed method is substantiated theoretically and researched experimentally. It is shown that the main component of the achieved effect is the gain in accuracy of the reduced AR-model in the Kullback–Leibler information metric. The results obtained are addressed to researchers and developers of systems and technologies for digital speech transmission over low-speed communication channels. [ABSTRACT FROM AUTHOR]

A detailed kinetic modeling of the noncatalytic processes of thermal pyrolysis and steam and carbon dioxide reforming of methane revealed almost completely identical kinetics of the methane conversion in these processes. This suggests that, in the temperature range 1400–1800 K, the initial stage of conversion of methane in all these processes is its thermal pyrolysis. The modeling results agree well with the experimental data on methane pyrolysis. For the temperature range examined, the Arrhenius expressions (pre-exponential factors and activation energy) were obtained in the first-order kinetics approximation for the rate of methane conversion in the processes studied. The expressions derived may be useful for making preliminary estimates and carrying out engineering calculations. [ABSTRACT FROM AUTHOR]

In this paper, we consider the problem of autoregressive modeling of a speech signal according to the data of its discrete Fourier transform on intervals of one speech frame (several milliseconds). Based on the information-theoretic approach, a novel method, in which two computational procedures, namely, iterative optimization of autoregressive parameters and their automatic amplitude scaling are separated from each other was developed. A full-scale experiment was set up and carried out. The main advantage of the new method in comparison with its known analogs is shown to be the extremely high rate of convergence of iterations to the optimal solution. [ABSTRACT FROM AUTHOR]

Multipotent mesenchymal stromal cells (MSC) are the key regulators of hematopoiesis. We studied changes in MSC characteristics in patients with myeloid leukemia and patients with lymphoproliferative diseases. MSC were obtained from the bone marrow of patients at the time of diagnostic puncture using a standard technique. Their proliferative potential and expression of genes associated with differentiation and regulation of hematopoiesis were studied. The total cell production of MSC in patients with leukemia at the onset of the disease did not differ from that in the group of healthy donors. The relative expression of the IL6, TGFb1 and TGFb2, PPARG genes was similar in all patients. The relative expression of the JAG1, LIF, IGF1, CSF1, IL1b, and IL1bR1 genes in MSC of patients with leukemia was enhanced and the relative expression of SDF1 was unchanged in comparison with MSC from donors. MSC from patients with leukemia were characterized by enhanced relative expression of PDGFRA and PDGFRB, and reduced expression of SOX9. Changes functions of the stromal microenvironment in patients with hemoblastoses attested to the role of stromal cells in the maintenance and spread of tumor cells. [ABSTRACT FROM AUTHOR]

A technique of numerical analysis of the elastoplastic axisymmetric stress–strain state of thin isotropic shells with different tensile and compressive properties under mechanical loading is described. The technique is based on constitutive equations of plasticity that include either the third invariant or mixed invariants of the stress deviator. To specify the constitutive equations, experimental data known from the literature and obtained in testing tubular iron specimens in tension, compression, and torsion are used. Numerical results are analyzed. [ABSTRACT FROM AUTHOR]

The paper reports the results of a kinetic modeling and thermodynamic analysis of non-catalytic steam reforming (NCSR) of methane and C2–C4 hydrocarbons at 1400–1800 K. The hydrocarbon-to-syngas conversion sequence and the time periods of the major process steps were identified. The initial step consists of hydrocarbon pyrolysis to acetylene and H2 with essentially no involvement of H2O. Noticeable H2O conversion starts at a significantly later point than thermal hydrocarbon conversion, under the effects of radicals formed from the pyrolysis. The H2O conversion results in the generation of OH● radicals, which subsequently react with acetylene to form CO and H2. The key step in the NCSR of C1–C4 hydrocarbons, as well as in their high-temperature interaction with CO2 (carbon-dioxide conversion) is conversion of the acetylene formed from the hydrocarbon pyrolysis. The study findings are important for the optimization of high-temperature syngas production via partial oxidation of hydrocarbons. [ABSTRACT FROM AUTHOR]

Trials of a combined process of matrix conversion of propane–butane mixture and subsequent catalytic steam conversion of the matrix conversion product gas to a hydrogen-containing gas were performed. The optimum ranges of process parameters for the matrix conversion of the propane–butane mixture were determined. Introduction of the additional step of catalytic steam conversion allows improvement of the parameters of the matrix conversion product gas, of which the hydrogen content is the most important parameter. [ABSTRACT FROM AUTHOR]

This study considers a new measure of distortions of speaker speech sounds that is invariant with respect to the gain of speech signal in a communication channel. Properties of the measure are investigated in comparison with its closest analogues. A series of theoretical features has been proved. The new measure is shown to combine advantages of the symmetric Itakura distance in relation to the noise immunity of automatic speech processing, on the one hand, and of the COSH distance in relation to the sensitivity to speech signal distortions, on the other hand. Using the proprietary software, an experiment was set up and conducted. Estimates of the new measure dependence on the signal-to-noise ratio were presented. It has been shown that the logarithmic presentation of this relationship has the pattern close to linear. The obtained results are intended to be used in development of new systems and upgrading of existing systems and technologies for digital signal processing and speech quality analysis under the noise exposure. [ABSTRACT FROM AUTHOR]

A method for the numerical analysis of the elastic and plastic stress–strain state of layered bodies of revolution made of isotropic and orthotropic materials is proposed. For isotropic materials, modified thermoradiation plasticity equations of deformation along trajectories of small curvature are used. The equations of elasticity are used to study the deformation of orthotropic materials. The dependence of the physical and mechanical properties of materials on temperature and radiation is taken into account. For the convenience of developing the algorithm, the relations between the components of the stress and strain tensors in an arbitrary element of the body are written in the form of a generalized Hooke's law for an orthotropic material with additional terms. The loading process is divided into a number of small stages. The components of the stress–strain state are determined at each stage using the method of successive approximations. As an example, the stress–strain state of a thin layered shell under thermomechanical loading and radiation exposure is considered. [ABSTRACT FROM AUTHOR]

The theory of branched-chain processes, created by the founder of the Russian school of chemical physics, Nikolai Nikolaevich Semenov, has become the foundation of modern ideas about the mechanism of gas-phase hydrocarbon conversion processes and the base for a deep understanding of the phenomena occurring in many related fields. However, throughout the 20th century, the chemical processing of hydrocarbon gases remained a secondary area of petroleum chemistry, since liquid petroleum hydrocarbons were the main hydrocarbon feedstock. A radical change in the situation after the start of industrial development of huge unconventional natural gas resources made it necessary to create cost-effective technologies for processing cheaper and more accessible gaseous hydrocarbons into basic petrochemical products. This article discusses new non-catalytic methods for processing hydrocarbon gases, developed at the Institute of Problems of Chemical Physics, Russian Academy of Sciences (IPCP RAS) and the Federal Research Center for Chemical Physics, Russian Academy of Sciences, and promising areas of their application. [ABSTRACT FROM AUTHOR]

Various options for designing the direct oxidation of natural gas to methanol are considered: flow-through, with a distributed supply of the oxidizer along the length of the reactor, and circulation. For each of the considered options for designing the process, the methanol yield was calculated, as well as the parameters at which the resulting blow-off gas can be used as a fuel. The optimal recycling rate in the circulation process has been determined. [ABSTRACT FROM AUTHOR]

The present paper discusses the problem of distortions in speech signals transmitted over a communication channel to a biometric system during voice-based remote identification. A possible rectification approach involves a preliminary correction of the frequency spectrum of the received signal based on the pre-distortion principle. Taking into account a priori uncertainty, a new information indicator of speech signal distortions is proposed, along with a method for its measurement under conditions of small observation samples. An example of fast practical implementation of the method based on a parametric spectral analysis algorithm is considered. Results of an experimental test of the proposed approach are provided for three different communication channel instantiations. It is shown that the proposed method facilitates the transformation of an initially distorted speech signal into compliance with a registered voice template using an acceptable algorithmic information discrimination criterion. The described approach may be used in existing biometric systems and speaker identification technologies. [ABSTRACT FROM AUTHOR]

The article considers the problem of automatic segmentation of a speech signal into phonetic units in conditions of their a priori uncertain spectral composition and correlation properties. A guaranteed significance level criterion is developed based on the information–theoretic approach. An example of practical application of this criterion is considered; a full-scale experiment is set up and conducted. It is shown that the proposed criterion can guarantee a stable significance level when processing speech frames of short duration. [ABSTRACT FROM AUTHOR]

The phenomenon of the voice signal acoustic variability in automatic speech recognition systems is considered. There are two varieties—intra- and inter-speaker speech variability. The probabilistic cluster model of minimal speech units in the Kullback–Leibler information metric is used for their mathematical description and comparison in magnitude. On its basis, theoretical estimates of the voice signal acoustic variability for each of its varieties are obtained separately. The effect of information security in systems with tuning to the authorized user voice is described and quantitatively characterized. The intra-speaker variability is negligible in comparison with the inter-speaker variability of speech, and therefore does not have a noticeable harmful effect on the effectiveness of automatic speech recognition. The computational experiment is set up to confirm and develop the theoretical research results, where two speech streams from two different speakers are considered. The author's software is used for its implementation. According to the experimental results we find that the level of inter-speaker speech variability in a number of cases goes beyond the inter-phonemic differences within a homogeneous speech flow. Therefore, in systems with tuning to the speaker voice, the effect of voice signal acoustic variability is not only unambiguously generally positive, namely: it is an information protection from unauthorized access, but also it is significant in terms of probability-theoretic relation. The obtained results are intended for the development of new and modernization of existing systems for automatic speech recognition, designed to work in a standalone mode. [ABSTRACT FROM AUTHOR]

Refactoring is an integral part of the modern software development process. Often, the refactoring must be performed at the global level with modifications in a large number of files. Making these modifications is a long and painstaking work. However, users rarely employ automated tools for this purpose because they consider them unreliable and difficult to use. In this paper, a new tool for transforming the source code is described. It is based on the intuitively clear specification of transformation rules in the form of short code fragments in C or C++. These rules describe the code before and after the transformation. We believe that, due to the absence of additional abstractions (such as domain-specific languages), this approach can be easily used in practice. Even though the tool uses source code templates, it operates on the level of the abstract syntax tree. This enables the tool to better analyze the code and verify the validity of transformations. [ABSTRACT FROM AUTHOR]

We studied changes in the bone tissue in patients with diffuse large B-cell lymphoma at the onset of the disease (N=41; before chemotherapy) and 5-16 years after the end of treatment (N=47). Osteodensitometry, biochemical markers of osteoporosis in the blood and urine, and gene expression in multipotent mesenchymal stromal cells were analyzed. In multipotent mesenchymal stromal cells of all patients, the expression of genes associated with bone and cartilage differentiation (FGF2, FGFR1, FGFR2, BGLAP, SPP1, TGFB1, and SOX9) was changed. In primary patients, the ratio of deoxypyridinoline/creatinine in the urine and blood level of β-cross-laps were increased, while plasma concentration of vitamin D was reduced, which indicates activation of bone resorption. No differences between the groups were revealed by osteodensitometry. No direct relationship between changes in gene expression in multipotent mesenchymal stromal cells and osteoporosis markers was found. The presence of a tumor in the body affects the bone marrow stroma, but achievement of remission and compensatory mechanisms provide age-appropriate condition of the bone tissue. [ABSTRACT FROM AUTHOR]

The article continues our previous work [V. V. Savchenko and A. V. Savchenko, Izmeritel'naya Tekhnika, No. 12, 46–52 (2019)]. We study the problem of automatic control of the quality of voice samples recorded and stored in the Unified Biometric System. We propose a solution of the problem of timely updates of the collected samples required because their consumer qualities are lost in the course of time. A new indicator of the acoustic quality of voice samples in the Kullback–Leibler information metric is investigated and a new procedure is proposed for measuring this indicator at the times of contact of the users with the system with service requests. An example of practical implementation of the proposed method in the real-time mode is demonstrated. By using software specially developed by the authors, we performed a full-scale experiment and obtained quantitative estimates of the period of updating of voice samples. Some recommendations concerning their practical application are given. The accumulated results can be used for the purposes of development of new systems and technologies (and upgrading of the existing systems) of automatic quality control and adaptive renewal of the biometric personal data samples. [ABSTRACT FROM AUTHOR]

An experimental study and detailed kinetic modeling of characteristics of the matrix conversion of a methane–oxygen mixture with the addition of hydrogen, carbon monoxide, synthesis gas, and steam have been carried out. It has been shown that the most significant effect on the product composition is provided by the admixture of steam, which reduces the yield of acetylene and at the same time increases the H2/CO ratio. The kinetic simulation results appear to agree well with the experimental data obtained. [ABSTRACT FROM AUTHOR]

Interaction of vinyl trichlorosilane with sodium salt of ricinoleic acid is investigated. It is established that the composition and structure of silicon-containing ethers depends on the content of crystallization water in sodium ricinoleate, and the concentration and nature of solvent. Thus, in the case of a mixture of absolute alcohol with ether and low content of crystallization water, the reaction proceeds by hydroxyl of alcohol to form salt-like compounds containing silicon. In the case of a salt with a high content of crystallization water, the reaction proceeds along two reaction centers with the formation of ether and ester simultaneously. The composition and structure of the obtained compounds were established using elemental analysis, IR, 1H, 13C NMR spectroscopy, and gel chromatography. It is proposed to use prepared organosilicon ethers of ricinoleic acid as additives to motor oils instead of castor oil. [ABSTRACT FROM AUTHOR]

The problem of automated quality control of audio recordings containing voice samples of individuals is considered. It is shown that in solving this problem the most acute impediment is the problem of small samples of observations. To overcome the problem, a new, high-speed method of acoustic measurements is proposed, based on the principle of relative stability of the frequency of the fundamental tone of a speech signal within a voice sample of short duration. An example of practical implementation of the developed method according to a scheme with inter-period signal accumulation is considered. Using proprietary software, a full-scale experiment was conducted in which statistical estimates of the effectiveness of the method in noise conditions were obtained. It is shown that when using the proposed method, if the signal-to-noise ratio is lower than 15 dB, an audio recording is rejected with a probability of 0.95 or more as unsuitable for biometric identification of a person. The results obtained are intended for use in the development of new systems and modernization of existing systems and technologies for collection and automated quality control of biometric personal data. The article is intended for a wide circle of specialists in the field of acoustic measurements and digital processing of speech signals, as well as for practitioners who organize the work of authorized organizations in preparing samples of biometric personal data for registration with the unified biometric system (UBS). [ABSTRACT FROM AUTHOR]

It is considered a problem of automatic speech recognition at basic, phonetic level of speech signal processing. It is researched a problem of noise-immunity increase. For its solution it is proposed a criterion of minimum information divergence of the signals with tuning to a speaker voice and automatic scaling of speech template to thin structure of observed (current) speech frame. An example of its practical realization is considered, efficiency characteristics are researched. Applying the author's software we carry out an experiment and obtain qualitative estimations of threshold signals gain in case of application of proposed criterion. It is shown than this gain can be 10 dB and greater under certain conditions. Obtained results and drawn conclusions are intended it to their application for development and modernization of existent systems and techniques of automatic processing and recognition of speech intended it to operation in conditions of intensive noise effect. [ABSTRACT FROM AUTHOR]

We consider the problem of determination of the intelligibility of speech of a speaker according to a finite fragment of the speech signal. It is shown that the main difficulties in the solution of this problem are connected with the necessity of analysis of small samples. To overcome the problem of small samples, we proposed a new high-speed method for measuring the intelligibility of speech signals on the sonic level of its perception. The proposed method is based on the information indicator of speech intelligibility in the Kullback-Leibler metric. We consider an example of practical realization of the new method with the use of a self-regression model of minimum sound units from the speech flow of a speaker. The characteristics of efficiency of the new method are analyzed. It is shown that, under certain conditions, the application of the information indicator enables us to realize the general systems principle of guaranteed result. On the basis of the software developed by the authors, we designed and performed full-scale experiments and established quantitative estimates for the speed of this method. It is shown that, with the help of this method, quite accurate and reliable estimates of the information indicator are obtained for short (2–3 min) segments of speech signals. The accumulated results and the conclusions made on their basis are intended for applications in the development of new systems and improvement of the existing systems of automatic speech processing and recognition intended for the operation in the real-time mode. [ABSTRACT FROM AUTHOR]

The INTernational Gamma-ray Astrophysics Laboratory (INTEGRAL) has detected the Short Gamma-Ray Burst (SGRB), GRB170817A with a signal-to-noise ratio of 4.6 and demonstrated its association with the binary neutron star merging event GW170817 detected by the LIGO and Virgo gravitational wave observatories. The association was immediately evident due to the timing and positional coincidence of this event with the initial error box, derived from gravitational wave (GW) measurements and the contemporaneous detection of a similar gamma-ray signal by Fermi/GBM. This SGRB was detected by the INTEGRAL SPI ACS about 1.7 s after the end of the GW emission, with a fluence of ( 1.4 ± 0.4 ) × 10 - 7 erg cm - 2 in the 75–2000 keV energy range. After the serendipitous detection of the short prompt GRB, INTEGRAL continued the planned observation for about 20 h, and then performed a targeted follow-up ToO observation lasting several days. This ToO observation provided a stringent upper limit on any electromagnetic signal in a very broad energy range, from 3 keV to 8 MeV, in particular constraining the soft gamma-ray afterglow flux to < 7.1 × - 11 erg cm - 2 s - 1 in the range 80–300 keV. Exploiting the unique capabilities of INTEGRAL, we constrained the gamma-ray line emission intensity from radioactive decays expected to be the principal source of the energy behind a kilonova event following a NS–NS coalescence. Finally, we put a stringent upper limit on any delayed bursting activity, for example, from a newly formed magnetar. The INTEGRAL prompt detection and the subsequent continuous observations at all wavelengths have provided important constraints on the high energy emission of the resulting kilonova and the post inspiral object: NS, BH, or a new exotic object. [ABSTRACT FROM AUTHOR]

Trials of oxidative cracking of ethane—propane—n-butane mixtures were performed on an installation with the productive capacity with respect to the gaseous feed of 5 m3 h−1. Ethylene, CO, and hydrogen are the major products of oxidative cracking of oil refinery gases; their total yield can exceed 90%. The yield of ethylene and CO is determined by the total concentration of alkanes in the mixture and is independent on the length of their hydrocarbon chain, whereas the hydrogen yield appreciably decreases with an increase in the alkane chain length. The trials demonstrated high efficiency of the production of ethylene, CO, and hydrogen by oxidative cracking of oil refinery gas mixture components. [ABSTRACT FROM AUTHOR]