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The study purpose is to measure the performance of the Vietnamese garment and textiles industry by means of the Negative Malmquist model using the data envelopment analysis (DEA) method. The empirical results presented the efficient, inefficient cases, and average efficiency for all garment and textile companies in Vietnam during from 2016 to 2020. The main findings determined that five companies, including HTG, TET, MSH, M10, and BDG possessed efficiency scores in whole terms. An overall picture of the garment and textiles industry in Vietnam is used to evaluate the operational process. The research recommends a feasible alternative method to deal with inefficient cases.

The melting temperature, the jumps of volume, enthalpy and entropy at the melting point, the isothermal compressibility, the thermal expansion coefficient, the heat capacity at constant volume, the Grüneisen parameter, the Debye temperature, the electrical resistivity, the thermal conductivity, and the thermal diffusivity for defective and perfect f.c.c. metals are studied by combining the statistical moment method (SMM), the limiting condition of the absolute stability of the crystalline state, the Clapeyron–Clausius equation, the Debye model, the Grüneisen equation, the Wiedemann–Franz law and the Mott equation. Numerical calculations are carried out for Au under high temperature and pressure. Calculated melting curve of Au is in a good agreement with experiments and other calculations. Obtained results are predictive and orient towards new experiments.

The paper is devoted to studying the possibility of using artificial neural networks (ANN) to estimate ground subsidence caused by underground mining. The experiments showed that the most suitable network structure is a network with three layers of perceptrons and four neurons in the hidden layer with the back propagation algorithm (BP) as a training algorithm. The subsidence observation data in the Mong Duong underground coal mine and other parameters, including: (1) the distance from the centre of the stope to the ground monitoring points; (2) the volume of mined-out space; (3) the positions of the ground points in the direction of the main cross-section of the trough; and (4) the time (presented by cycle number), were used as the input data for the ANN. The findings showed that the selected model was suitable for predicting subsidence along the main profile within the subsidence trough. The prediction accuracy depended on the number of cycles used for the network training as well as the time interval between the predicted cycle and the last cycle in the training dataset. When the number of monitoring cycles used for the network training was greater than eight, the largest values of RMS and MAE were less than 10 % compared to the actual maximum subsidence value for each cycle. If the network training was less than eight cycles, the results of prediction did not meet the accuracy requirements.

Introduction To investigate clinical, laboratory findings and identify pre-operative variables associated with increased waiting time to surgery (WTS) and length of hospital stay (LOS) among hip fracture patients. Material and methods This prospective study is conducted between April 2020 and April 2021. Patients’ information was collected from medical records and subjected to analysis using a univariate and multivariate model. Results The study included 118 patients in a mean age of 79.5 years, and the majority were female (68.6 %). Overall, 66.9 % of the patients had at least one comorbidity. Almost all (95.8 %) patients had fractures due to a low-impact fall and an intertrochanteric fracture was the predominant type (61.9 %). The most abnormal laboratory findings at admission were elevated C-reactive protein (CRP) levels (94.9 %) followed by decreased mineral density (85.1 %), anaemia (81.4 %), electrolyte abnormalities (69.4 %) and hypoalbuminemia (66.1 %). The mean of WTS among 115 patients undergoing surgical treatment was 52.1 ± 47 hours and no patient-related factors had a significant influence on WTS. The mean hospital LOS was 15.9 ± 4.7 days. Marked elevation of CRP level (OR = 3.317, p = 0.042), type of surgery (OR = 4.413, p = 0.005) and WTS (OR = 4.602, p = 0.001) were independent predictors of prolonged LOS. Conclusion Most patients with hip fractures are elderly and suffer from many comorbidities and laboratory abnormalities. No patient-related factors are predictors of WTS but the elevation of CRP, type of surgery and time of waiting to surgery influence the LOS.

The problem of compensation of external disturbing influences for MIMO system with input delay is important and relevant. A solution to this problem is proposed in the problems of dynamic objects control and in a number of others. The proposed method is based on the principle of an internal model and requires the identification of perturbation parameters. At the first stage, a scheme for extracting a disturbance is presented which is represented as a sinusoidal signal with an unknown frequency, amplitude, and phase. At the second stage, the problem of identifying the frequencies of a sinusoidal and multisinusoidal signal is solved. In the last stage, an algorithm for stabilizing the state of the object to zero is developed using feedback. A new scheme for compensating external disturbances for a MIMO system with an input delay is proposed. A new algorithm for identifying the frequencies of a multisinusoidal signal is proposed. The analysis of the possibilities of the proposed estimation method using computer simulation in the MATLAB Simulink environment is carried out. The developed method can be effectively applied to a wide class of applied tasks related to the control of robots and robotic manipulators for various purposes.

Introduction. Real-time calibration is essential for maintaining the performance of modern digital phased antenna array (DPAA) systems. Previous papers have proposed a method of real-time internal calibration for all receiving channels. This method uses a calibration signal (CalSig) of the same frequency spectrum as the received signal, modulated in phase and amplitude by the binary phase-shift keying (BPSK) and on–off keying (OOK) codes, respectively. With the purpose of improving the method, we propose an algorithm for estimating the phase and amplitude parameters of each receiving channel on the basis of continuous phase correlation accumulation of CalSig samples.Aim. Synthesis of algorithms and procedures for real-time internal calibration of receiving channels in digital phased antenna arrays.Materials and methods. Calibration algorithms and calibration procedure were analyzed and synthesized using the methods of systems analysis. In addition, the methods of systems engineering and technology, digital processing of radar signals and synthesis of building test models close to actual requirements were applied.Results. The advantage of the proposed calibration algorithm and calibration procedure consists in using CalSig modulated by the BPSK and OOK codes. The results obtained on a small DPAA system with four receiving channels gave the error of phase and amplitude lower than 0.3° and 0.05 dB, and the error of main beam direction lower than 0.2°. The results of testing the developed DPAA model confirmed the simplicity and high calibration accuracy of the approach under study.Conclusion. The proposed calibration algorithm and calibration procedure have the advantage over those proposed in previous research in terms of simplicity and resource efficiency. This fact determines the prospects for using the obtained results.

The paper presents a solution for identifying the frequency of a sinusoidal signal with constant parameters. The issue can be relevant for compensation of disturbances, control of dynamic objects, and other tasks. The authors propose a method to improve the quality of the estimation of the sinusoidal signal frequency and to ensure exponential convergence to zero of the estimation errors. At the first stage, the sinusoidal signal is presented as an output signal of a linear generator of finite dimension. The signal parameters (amplitude, phase, and frequency) are unknown. At the second stage, the Jordan form of the matrix and the delay operator are applied to parameterize the sinusoidal signal. After a series of special transformations, the simplest equation is obtained containing product of one frequency-dependent unknown parameter and a known function of time. To find the unknown parameter, the authors used the methods of gradient descent and least squares. A new algorithm for the parametrization of a sinusoidal signal is presented. The solution is based on transforming the signal model to a linear regression equation. The problem is solved using gradient descent and least squares tuning methods based on a linear regression equation obtained by parametrizing a sinusoidal signal. The results involve the analysis of the capabilities of the proposed estimation method using computer modeling in the Matlab environment (Simulink). The results confirmed the convergence of the frequency estimation errors to the true values. The developed method can be effectively applied to a wide class of tasks related to compensating or suppressing disturbances described by sinusoidal or multisinusoidal signals, for example, to control a surface vessel with compensation of sinusoidal disturbances.

Introduction. With the development of technology and science, passive radar systems operating on the basis of third-party transmitters of illumination signal sources are increasingly attracting research interest. The use of satellite systems as transmitters of opportunity for a radar station makes it possible to monitor coastal sea areas, where the ground sources of illumination signals are absent. Satellite systems can cover any point on the Earth's surface. Passive radar systems can be used to determine the location of ships and monitor navigation. They are also promising as part of vessel traffic control systems.Aim. To develop a model of a passive radar system that uses satellite systems as third-party sources of illumination signals and to conduct an experimental study of a system for monitoring ships in coastal waters.Materials and methods. The AA2-KKС antennas of satellite signals and radio recording tools based on the universal USRP B210 board were used. Signal processing was performed using a program developed in the MATLAB environment.Results. An algorithm for processing satellite signals of the GPS global navigation system in a passive radar system is proposed. An experimental model of the receiving station for such a radar monitoring system was created on the basis of a data input device for a universal USRP board of the B210 series. Experimental results for the receiving station using the satellite signal GPS L1 C/A-code for coastal monitoring were obtained.Conclusion. The developed experimental model of a passive radar receiving station using third-party transmitters of GPS satellitebased illumination signals on the L1 frequency range of the C/A-code type can be used for detecting ships and monitoring coastal navigation. Future research will consider a multiposition modification of such a monitoring system for improving its detection quality and increasing its target positioning accuracy.

The paper considers the optical systems of virtual reality, which use an optical wedge to eliminate or reduce the conflict of convergence and accommodation (vergence- ccommodation conflict, VAC). The inclined surfaces of the optical wedge introduce specific aberrations into the optical system that can critically affect image quality. The authors analyzed wedge aberrations using relationships derived from the third-order aberration theory. In contrast to existing approaches, the relationships were obtained without the assumption of a small refractive angle or wedge thickness. The results demonstrate that in the scheme with an optical wedge, with characteristics typical for virtual reality systems, the dependence of astigmatism on the angular field is linear and significantly exceeds the other types of aberrations. It is shown that to obtain a high-quality image, the most successful compensation for such aberration can be achieved by using diffractive optical elements (kinoforms) or a Fresnel lens. The paper gives examples of optical systems with a wedge, developed taking into account the requirements for the overall dimensions of virtual reality systems and image quality. The obtained ratios for the aberrations of the optical wedge and the inclined surface make it possible to evaluate the correction capabilities of schemes where such elements are used with arbitrary characteristics. The proposed solutions can be used in virtual reality systems with a reduced value of vergence-accommodation conflict.

Khanh Hoa coal mine (Thai Nguyen province) is one of the largest coal mines in the north of Vietnam. For many years, this area suffered from underground fires at coal mine waste dumps, seriously affecting production activities and the environment. This paper presents the results of classification of underground fire areas at Khanh Hoa coal mine using Normalized Diference Coal Fire Index (NDCFI). 03 Landsat 8 OLI_TIRS images taken on December 2, 2013, December 10, 2016, and December 3, 2019 were used to calculate NDCFI index, and then classify the underground fire areas by thresholding method. In the study, the land surface temperature was also calculated from Landsat 8 thermal infrared bands data, and then compared with the results of underground coal fire classification at Khanh Hoa coal mine. The obtained results showed that the NDCFI index can be used effectively in detecting and monitoring underground fire areas at coal mines. The use of the NDCFI index also has many advantages due to its calculation simplicity and rapidness compared to other methods for classifying underground coal fire areas.

Background. The central regions of Vietnam are of strategic importance for the Republic, being, in fact, the gateway to the ASEAN countries. Investing in the exploration and evaluation of mineral resources, in particular ore minerals hidden at great depths, is a specific and necessary task for the country.Aim. To clarify the structural-tectonic scheme of the analysed area and to identify the main fault systems and zoning of the Central Vietnam area by the gravitational field based on classification algorithms.Materials and methods. The objectives were achieved by assessing the total gradient of the gravitational field, analysing the distribution of the field variance and the results of tracing the axes of the gravitational field anomaly. Interpretation processing of gravity data was carried out using the “COSCAD 3D” computer technology of statistical and spectral correlation data analysis.Results. The defined fault systems, which play an important role in the processes of mineral formation, have a northwestern, northeastern and latitudinal strike. The zoning of the study area according to the gravitational field, its characteristics and available geological information made it possible to identify 13 homogeneous areas. Each area is characterised by a certain level of gravitational field, the values of dispersion and total field gradient, as well as correlations between attributes. The classification results confirms the complexity of the geological structure of the area under study and the presence of three main strikes of the systems of tectonic dislocations – northwestern, northeastern and latitudinal.Conclusions. A large number of tectonic dislocations of various strikes and intensities, revealed using the methods of the probabilistic-statistical approach, implemented in the “COSCAD 3D” computer technology, indicates that the area under study is promising in terms of ore deposits.

The epidemic situation and etiological factors of enterovirus infection in Russia and Vietnam were analysed and compared. The identified strains of enteroviruses of 47 types, which circulated in Russia in 2018–2019, belonged to different species: Enterovirus species A (CV-A2, CV-A4, CV-A6, CV-A8, CV-A10, CV-A16, EV-A71), as well as Enterovirus species B and Enterovirus species C. The strains isolated from 87 children from southern Vietnam hospitalised in 2018–2019 into infectious hospitals while having enterovirus infection with exanthema were also studied. All identified strains were represented by Enterovirus species A: EV-A71 — 59 strains, CV-A10 — 20 strains, CV-A16 — 5 strains, CV-A6 — two strains and CV-A2 — one strain. Out of 59 viruses EV-A71, 53 strains belonged to genotype C4 and 6 strains belonged to genotype B5. The sequences of EV-A71 strains of genotype C4 from South Vietnam formed a monophyletic cluster with the sequences of EV-A71 viruses which circulated during 2016–2018 in different provinces of China, and they were very close to EV-A71 strains of the same genotype from the Yunnan Province. These strains were genetically different from Russian viruses and Vietnamese viruses identified in the years 2003–2005 and 2011– 2012. Most of the cases of enterovirus infection from southern Vietnam (78%) caused by EV-A71 virus of genotype C4 were reported in three provinces located in southern Vietnam in the Mekong Delta. The epidemic process and the etiology of enterovirus infection in Russia and Vietnam have common features. At the same time, the epidemic situation in these countries is not the same. The incidence of enterovirus infection is influenced by geographic, climatic, economic and demographic factors that differ in two countries. In the majority of territories of Russia, the climate is temperate or cold, seasonal rises in the incidence rates of enterovirus infection usually occur in the summer, when people go on vacation, spend a lot of time outdoors and swim in open reservoirs. In Vietnam, a constant high-level temperature, a high population density and a large proportion of children determine the higher incidence of enterovirus infection, especially in the southern provinces of Vietnam, compared to Russia. The fact that more than 20% of the Vietnamese population lives in the Mekong Delta, which is the largest river in Indochina, has a significant impact on the epidemic process of enterovirus infection in South Vietnam. The Mekong River which flows through China, Laos, Thailand, Cambodia and Vietnam, and carries huge streams of water, including rainstorm waters and sewages, from all of these countries into the southern provinces of Vietnam, which have the highest incidence rates of enterovirus infection in the country. The results of the research underline the importance of active epidemiological and virological surveillance of enterovirus infection, which plays the key role in informing the public health authorities about the changes in the epidemic situation in order to take appropriate measures and develop the prevention strategies. The goal of anti-epidemic and preventive measures is to reduce the incidence of enterovirus infection and the economic burden of this infection for Russia and Vietnam.

Introduction. Spectrally efficient frequency division multiplexing (SEFDM) is a promising technology for improving spectral efficiency. Since SEFDM signals transmitted on subcarriers are not orthogonal, interchannel interference occurs due to the mutual influence of signals transmitted on adjacent subcarriers. Algorithms for receiving SEFDM signals can be distinguished into element-by-element coherent detection and maximum-likelihood sequence estimation (MLSE). The former method, although being simpler, is characterized by a low bit error rate performance. The latter method, although providing for a higher energy efficiency, is more complicated and does not allow high absolute message rates.Aim. To consider a trade-off solution to the problem of coherent detection of SEFDM signals under the condition of significant interchannel interference, namely, the use of an iterative algorithm of element-by-element processing with decision feedback at each subcarrier frequency.Materials and methods. Analytical expressions for the operation of a demodulator solver were derived. A simulation model for transmission of SEFDM signals was built in the MatLab environment, including element-by-element detection with decision feedback.Results. The simulation results confirmed the efficiency of the proposed algorithm. For error probabilities p =102…103, the energy gains reach values from 0.2 to 7.5 dB for different values of the non-orthogonal subcarrier spacing. At the same time, the efficiency of the detection algorithm with decision feedback turns out to be significantly lower than that when using the detection algorithm MLSE.Conclusion. The proposed detection algorithm can be used in future generations of mobile communications, which require high transmission rates. By reducing the computational complexity of the algorithm, it is possible to provide for a lower power consumption of mobile devices.

The article is devoted to solving the problem of improving the energy efficiency of power plants of high-speed lowtonnage (planing) vessels used for passenger transportation between coastal settlements on the example of the port of Vladivostok located on the Muravyov-Amursky Peninsula, which has mainly land communication with settlements located on the coast. The oversaturation of motor transport, due to the need for communication between localities, which are usually characterized by dense buildings, is one of the main causes of many hours of traffic congestion, which worsen the environmental situation and increase social tension in society. At the same time, the tourist attractiveness of Primorye is also decreasing. One of the promising areas for solving this transport problem is the use of low-tonnage passenger vessels, in particular planing vessels, with hybrid electrified power propulsion systems. According to the available data, such vessels have reduced consumption of fuel and lubricants necessary for the operation of power plants and reduction in harmful emissions into the surrounding atmosphere by more than two times compared to similar traditional diesel vessels. In addition, the prospects of the proposed scientific and technical solution are due to the reduction in the time of passenger transportation while reducing the cost of travel.

Vietnam is an endemic territory of the South-East Asia in terms of the prevalence of hepatitis E virus. However, the data on the prevalence of HEV infection among the indigenous population of Vietnam are limited, whereas the data on various minor ethnic groups are not available. Рopulation of the Northern province Hà Giang is characterized by ethnic diversity and consists of about 22 ethnic groups that have preserved their ethnic identity determining the features of their lifestyle and farming. The goal of the current study was to conduct a cross-sectional examination to assess prevalence of serological markers of HEV infection in the indigenous population of the Northern province of Vietnam, Hà Giang. Materials and methods. A total of 1127 healthy indigenous residents aged 18 to 83 years (average age 42.8±1.5) who lived in three regions (Yên Minh, Bắc Mê and Đông Văn) of Hà Giang province in 2019 were enrolled in the study. The presence of HEV-specific IgG antibodies (anti-HEV IgG) was determined by the ELISA using kits “DS-IFA-ANTI-HEV-G” (LLC NPO “Diagnostic Systems”, Russia). Results. The prevalence of anti-HEV IgG antibodies in the indigenous population in the Hà Giang province was 74.4% (838/1127; 95% CI 71.7–76.8), with the peak occurrence of anti-HEV IgG (87.6%) found in Đông Văn region, which was significantly higher compared to those in the Bắc Mê (χ2 = 16.37, p = 0.000052) and Yên Minh (χ2 = 214.64, p < 0.00001) regions. The Yên Minh Region was characterized by the lowest percentage of subjects involved in the epidemic process (χ2 = 77.55, p < 0.00001). No significant gender-related differences were detected in antiHEV IgG level both in general and in individual regions. The peak frequency of anti-HEV IgG (85.9%) was found in the H’mong ethnic group, which was significantly higher than in the Tay ethnic groups (χ2 = 77.32, p < 0.00001) and in the remaining minor ethnic groups (χ2 = 63.44, p < 0.00001). Conclusion. The results of this study indicate a high seroprevalence of hepatitis E virus in the minor ethnic groups, which preserve the national lifestyle in the Hà Giang province of the Northern Vietnam. As the Hà Giang province is located in remote mountain areas, a number of which are still difficult to access, its low economic status, poor sanitary and hygienic living conditions, lack of high-quality water supply, multinational population following different lifestyles, the contact of population with natural potential sources of HEV infection, including various wild and domestic animals, contribute to the successful spread of the hepatitis E virus in the region and the involvement of all populational age groups in the epidemic process. Taking into account the rapid development of the tourism industry in the Hà Giang Province particularly in the Đông Văn Region, where the Đông Văn Karst Plateau Geopark being recognized by UNESCO as national treasure is located, the results of this study emphasize a need to plan and perform the events aimed for preventing and monitoring HEV infection in endemic regions in Vietnam in order to reduce a risk of spread of hepatitis E virus not only inside, but also outside the country.

Introduction. Ventricular late potentials (VLP) are predictors of cardiac disorders such as sudden death syndrome, myocardial infarction and ventricular tachyarrhythmias. Therefore, VLP assessment allows the severity and possible dangerous consequences of such disorders to be predicted.Aim. To determine errors associated with VLP assessment by high-resolution 12-lead ECG recordings.Materials and methods. VLPs were determined by the modulus of the cardiac electrical vector using signals from orthogonal leads. The conversion error was assessed using synchronous ECG recordings of 12-channel and orthogonal leads, the method of digital filtering (to reduce noise and interference) and the method of identifying characteristic points of the QRS complex and VLPs.Results. The conversion of 12-lead ECG signals into orthogonal signals results in errors associated with the assessment of both the modulus of the cardiac electrical vector and all VLP indicators. The Kors transformation was shown to provide the minimum errors when assessing the cardiac electrical vector modulus in the QRS area, with the errors related to the VRMS assessment not exceeding 0.084 %. The estimation of the QRSd and LAS errors should consider the nature of VLP variations and the zone of uncertainty in their assessment. The ambiguity of the results of assessing the boundaries of violations and the absence of pathologies in cardiac ventricular depolarization indicates the influence of a large number of factors on research accuracy. Errors in the assessment of these factors may result in under- and overestimation of dangerous heart rhythm disturbances and incorrect prediction of the patient' state.Conclusion. The obtained results can be used for reducing errors associated with the assessment of VLP indicators, improving the diagnostic accuracy of dangerous heart rhythm disturbances and predicting disease exacerbation due to structural and morphological disorders of the myocardium.

The article presents a new method for diagnosing the technical condition of radio-electronic components, combining the methods of thermal diagnostics with the technologies of artificial neural networks. The structure of the method is shown, and the composition of the functional blocks is determined. The implementation of the method is a symbiosis of technologies for mathematical and simulation modeling of the technical state of a radio-electronic device with its physical tests and research of characteristics. When developing the method, specialized software tools for design and circuit design were actively used, such as Altium Designer CAD, SolidWorks, NI Multisim, the FloTHERM PCB thermal analysis module, as well as the MATLAB mathematical modeling and calculation package. With the help of these tools, a number of studies were carried out, including sets of numerical values of the power of circuit elements and temperature indicators of the printing unit, both for the correct state of the device and in states with artificially introduced defects. They, in turn, became the basis of the database of electronic node failures. To implement diagnostic procedures and identify the technical condition, an artificial neural network based on selforganizing Kohonen maps was created, its structure, parameters and algorithms of functioning were determined. The diagnostic procedure is based on the analysis of information from the fault database and its comparison with experimental data obtained as a result of a physical experiment. The results of the study showed that the network automatically classifies the characteristic defects of electronic components using the algorithms embedded in it. The list of characteristic defects in the proposed diagnostic method is limited to a discrete set of the most common faults, because, as their number increases, the use of the self-organizing Kohonen network for automatic classification becomes much more complicated and ineffective in terms of performance and reliability of identification. Among the advantages of this technology, it should be noted that the Kohonen network has the ability to convert largedimensional input data into a two-dimensional array. So, the results are easy to visualize and convenient to use when generating reports and recommendations for subsequent decision-making about the possibility of using an electronic device.

Recent developments show that an increasing number of organisations, regardless of type and size, understand that there is a need for them to make an active contribution to society, both socially and environmentally, while maintaining their financial profitability. It is no longer possible to waste resources and ignore the expectations of both internal and external stakeholders. To address these developments, all organisations are required to adapt their business models. Against this background, this paper provides a systematic review of the extant research on sustainable business models (SBMs) in smalland medium-sized enterprises (SMEs) to establish the current body of knowledge and, on this basis, to suggest some promising avenues for future research. Given the impact of SMEs on the majority of economies and their consequent role in addressing present and future societal challenges, there is a clear justification for this study. The review of 85 refereed articles shows that, although a good body of knowledge about the topic has been developed during the period covered in this study, there is still a need for further rigorous research. It appears that certain shortcomings, stressed by some researchers in the past, still prevail. The study’s findings advance the current understanding of SBMs in SMEs and highlight several promising research avenues that scholars who are interested in the study of SBMs, in general, and SBMs in SMEs, in particular, might address.

In this paper, the problem of segmentation of halftone images is considered, in which areas of local maxima and minima (extrema) are distinguished with a monotonic change in the brightness of pixels from local extrema to the boundaries of areas. To solve this problem, a mathematical model is proposed and a segmentation algorithm is developed on the basis of counter-wave growing of local extremum regions. The developed algorithm differs from the known segmentation algorithms by using a set of brightness thresholds (by the number of regions), varying by one in each cycle, starting from the values of local extrema, taking into account the increase or decrease in brightness to select adjacent pixels that are attached to the regions formed from these local extrema. The algorithm provides a greater deviation of pixel brightness from the average value within the region compared to known segmentation algorithms. This does not allow evaluating its efficiency using known indicators based on the variance of the brightness within the region. In this regard, estimates of the monotonicity of changes in the brightness of regions are proposed based on a) the shortest distances from each pixel of the region to the corresponding local extremum along the routes determined by the maximum increase (for the region of the local maximum) or decrease (for the region of the local minimum) the brightness of pixels and b) taking into account the number pixels that break the monotony of the segment brightness change. Using these estimates, it is shown that the proposed algorithm provides segmentation of artificial and natural grayscale images with a monotonic change in the brightness of pixels in the areas of local extrema. These properties allow us to consider the developed algorithm as a basis for the selection of texels, spots, low-contrast objects in images.

The processes of reactive magnetron sputtering of a V target in Ar/O2 gas mixture are investigated. It was found that when using a pulsed current for sputtering and a pressure in the chamber less than 0.06 Pa, the intensities of the emission lines of vanadium at 437.922 nm, argon at 750.386 nm, and oxygen at 777.417 nm with a change in the oxygen concentration in Ar/O2 gas mixtures (ГO2) have no hysteresis and unambiguously depend on the parameters of the sputtering process, which makes it possible to stabilize the process without using feedback systems. By monitoring the sputtering process by optical emission spectroscopy and depositing films on a rotating substrate of diameter 100 mm, vanadium oxide (VOx) films with nonuniformity thickness less than ±2.4 % and surface resistance less than ±2.5 % were obtained. Studies by transmission line method of the influence of the parameters of the reactive magnetron sputtering and subsequent annealing at O2 pressure of 0.04 Pa on the characteristics of thermoresistive structures based on VOx films showed that when the contacts are deposited without ion cleaning, the current-voltage characteristics (IV) and the dependence of the resistance on the length of resistors R(L) are nonlinear, which indicates the presence of a potential barrier in the contacts. Preliminary ion cleaning can significantly improve the linearity of the IV characteristic. The most linear IV characteristics were obtained for Ti contacts. However, the specific contact resistance of the VOx/Ti contact increases with an increase in the oxidation state of the VOx films and reaches ρc = 0.1 Ohm·m2 at the specific resistance of vanadium oxide ρ = 0.1 Ohm·m. The analysis of the dependences of the temperature coefficient of resistance (TCR) and ρ of VOx films on the annealing temperature showed that, upon annealing, ρ and TCR slightly decrease, i. e. there occurs a partial deoxidation of the films. However, unlike annealing at atmospheric pressure, there are no temperature regions at which a sharp decrease in the resistivity and TCR occurs.

Bioactive glasses (Bioglasses) are widely synthesized by the conventional sol-gel method consisting of two main steps for sol and gel formation. However, the conversion from sol to gel requires a long time (5–7 days). In this study, the hydrothermal system was used to quickly synthesize the bioactive glass by reducing the conversion time from sol to gel. The hydrothermal assisted conventional sol-gel method was applied for synthesis of the bioactive glass 70SiO2–30CaO (mol%) (noted as 70S30C). The synthetic glass was investigated by the physical-chemical techniques. The ‘‘in vitro’’ experiments in SBF (Simulated Body Fluid) solution was also performed to evaluate the bioactivity of synthetic material. The obtained results show that the bioactive glass 70S30C was successfully elaborated by using the hydrothermal assisted conventional sol-gel method. The consuming time was reduced compared to the conventional method. The physical-chemical characterization confirmed that the synthetic glass is amorphous material with mesoporous structure consisting of interconnected particles. The specific surface area, pore volume and average pore diameter of synthetic glass were 142.8 m2/g, 0.52 cm3/g, and 19.1 nm, respectively. Furthermore, synthetic bioactive glass exhibited interesting bioactivity when immersed in simulated body fluid (SBF) solution for 1 days and good biocompatibility when cultured in cellular media.

Introduction. Requirements for the quality of information about the trajectory of moving objects provided by sensor networks are increasingly becoming more stringent. For Information and Data Processing Centers (DPC) at control and management command posts, the issue of information mapping and forming the true trajectories of moving objects in the area of intersection of network detection zones is of particular importance. The use of conventional approaches to solving this problem involves issues related to ensuring the efficient provision of users with complete and reliable information about trajectories in real time. In this article, wee propose a new approach to solving this problem using data mining theory, in particular, the methods of data clustering theory. Based on an analysis of the process of processing radar data in a DPC and its similarity with that of data clustering, we synthesized an algorithm for processing the trajectories of moving objects. The algorithm was verified by modelling and experimental research.Aim. To develop a generalized scheme for processing object trajectories (TP) in a DPC and to synthesized a TP algorithm using the methods of data clustering theory.Materials and methods. Data Clustering theory, Systems Engineering theory, Radar Data processing theory (RD), methods of mathematical modelling and experimental research.Results. Based on an analysis of the essence of radar data processing (RD) in a DPC and its similarity with the process of data clustering, an algorithm for processing the trajectories of moving objects was synthesized and verified by modelling and experimental research. A generalized scheme for processing the trajectories of moving objects in a DPC and a TP algorithm for a DPC were synthesized.Conclusions. An algorithm for processing object trajectories was proposed based on a new approach of data clustering theory. A generalized scheme and an algorithm for processing object trajectories (TP) in a DPC were suggested. These developments can be effectively applied in various models, e.g. centralized, hierarchical and decentralized. The synthesized algorithm can provide output information about the true identified trajectories in terms of various indicators of data processing systems (DPS).

THE PURPUSE. The paper considers the influence of the nature of organic solvents on the process of separation of an antioxidant additive added to transformer oil at a concentration of up to 0.40% by weight, and organic solvents used as selective extractants. Based on the analysis of literature data, it is shown that mineral transformer oil is a complex hydrocarbon composition that undergoes oxidative degradation during operation, leading to aging of transformer oil and deterioration of technical conditions of operation of transformer electrical equipment. As a result of this process, peroxide compounds appear in transformer oil, which affect its color, oxidation stability, aging resistance, compatibility with structural parts of equipment, etc. Gas -liquid chromatography was used to determine the "Ionol" antioxidant additive and organic extractants in transformer oil. Experiments were performed on a chromatograph of Chromosomes GC -1000 with a flame ionization detector and a quartz capillary column 30 m long, 0.32 mm in diamet er, filled with a fixed liquid phase Valko Bond VB-WAX P/n with a film thickness of 0.5 microns. The sample was dosed into the gas-liquid chromatograph injector using an automatic liquid dispenser DAZH-23, designed for entering up to twenty-three samples of sorbates and controlled by a computer with the appropriate software.METHODS. Aliphatic alcohols from C1 to C5 were studied as extractants of the antioxidant additive, which are well separated from the ionol both under isothermal conditions and in the mode of linear programming of the column temperature from 40 to 220 °C. Under these conditions the chromatogram of the separation of antioxidant additives, and aliphatic alcohols, which are used to calculate their relative retained volumes, the asymmetry of chromatographic peaks and the column efficiency, which depends on the physico -chemical nature of the solutes to be analyzed and the conditions of the chromatographic experiment.RESULTS. The dependence of the relative volume of retention of aliphatic alcohols on their permittivity, which has a nonlinear form, is established. At the same time, with a decrease in the chain length of alkyl substituents in the aliphatic alcohol molecule, there is a tendency to increase their permittivity. The dependence of the relative retained volume of aliphatic alcohols on the selectivity coefficient of separation with Ionol is linear. In this case, the most optimal separation selectivity, approaching one, is characteristic of the Ionol – Butanol-1 pair. It is shown that the dependence of the logarithm of the retention time of aliphatic alcohols on their boiling points is linear both at a low temperature of the chromatographic column (40 °C) and at a higher temperature (more than 100 °C). CONCLUSION. At the same time, the angle of inclination of the corresponding lines changes in the boiling point of organic solvents, which is associated with a change in the sorption mechanism in a capillary chromatographic column filled with a polar stationary phase.

The paper presents main trends in growth and generation of waste, depending on increase of world GDP and the population of the planet. The main directions in extending the concept of national strategies for sustainable development have been considered with due account of energy and resource conservation problems, as well as the need for the rational use of natural and secondary resources in all countries of the world community. The energy potential use of combustible waste that has not found technological application is considered by many countries as one of the priority areas in the field of unconventional energy. The paper describes the main directions in application of the technology for briquetting multicomponent compositions into solid fuel. The developed production technology makes it possible to process waste products by briquetting them with the addition of various binders, and on the example of a binder component in the form of viscous hydrocarbon-containing waste, the main technological features of obtaining solid multicomponent fuel are presented in the paper. The paper describes the equipment for electrohydraulic treatment, which operates as a part of the preparation line for briquetting of the applied oily waste and that allows to reduce the sulphur content in the waste used, and such approach in general permits to regulate the environmental characteristics of harmful substance emissions at the maximum acceptable level. Taking into account the application aspects of the technology for wet briquetting of materials, the paper reflects the main results of the obtained dependences of humidity on productivity according to the content of the binder component. The proposed algorithm for solving the problem makes it possible to rationally use of substandard combustible industrial waste to obtain a multicomponent solid fuel, while at the production stage, the energy and environmental aspects of the resulting fuel are taken into account with due consideration of the component composition of the fuel.

Last decade saw growing interest to innovative technologies in methods of teaching Russian as a foreign language (henceforward RFL). The article presents a review of most recent scientific publications on modern computer technologies. The material of the research includes conference papers, manuals, monographs, dissertations of 2018-2019, materials of congresses of International Association of Teachers of Russian Language and Literature (MAPRYAL) (2016, 2019), Russian Society of Russian Language and Literature Teachers (ROPRYAL) (2015, 2018), articles in scientific journals “Russian Language Abroad” and “The World of Russian Word” which are considered to be the most authoritative journals in the sphere of methods of teaching RFL. The research methods are descriptive and statistic methods, method of continuous sampling. The research revealed main issues on possibilities and reasonability of using innovative technologies in teaching RFL. The growing number of publications on the issue shows the perspectives of innovative technologies in teaching RFL.

THE PURPOSE. Transformer oil is widely used in high-voltage electrical equipment and acts as a dielectric and also as a cooling medium. It consists of a complex mixture of hydrocarbon compositions with various impurity compounds. During the operation of oil -filled electrical equipment under the influence of the technological operating conditions of high -voltage devices, aging of both transformer oil and solid insulation occurs. In this case, the dielectric properties deteriorate, which can damage the transformer equipme nt. METHODS. To increase the service life of oil-filled electrical equipment, an antioxidant additive is introduced into the transformer oil at the stage of its manufacture, which is most often used as ionol, the concentration of which must be constantly controlled by various instrumental methods. To determine the antioxidant additive in transformer oil, a sample preparation system is used based on liquid-phase extraction with selective solvents, which are used as aliphatic alcohols of various physical and chemical nature. RESULTS. It has been established that ethyl alcohol, which is widely used in the sample preparation system for liquid extraction of ionol, contains a significant amount of water, which has a negative effect on the process of ionol extracti on from transformer oil. In addition, the composition of ethyl alcohol contains impurity substances that can have a negative effect on the process of liquid-phase extraction of ionol from transformer oil. The generalized data on the physicochemical properties of extractants used to extract ionol from transformer oil are presented. CONLUSION. It has been shown that butanol is the most promising organic solvent for the extraction of ionol, which has a higher boiling point compared to ethyl alcohol and contains a small amount of water. It was found that the selectivity of the chromatographic separation of butanol components with an elevated column temperature increases. At the same time, the separation efficiency increases as the number of theoretical plates per meter of chromatographic column increases. As the temperature of the capillary column increases, the symmetry of the chromatographic peaks of the separated components also increases.

Nanocrystalline copper (II) ferrite with a spinel structure doped with holmium was synthesized by co-precipitation using an aqueous solution of NaOH as a precipitant and subsequent annealing at 800°C for 60 min. The doping limit was determined by X-ray phase analysis. The similarity of the real and nominal compositions of the doped samples was established by energy-dispersive X-ray spectroscopy using a scanning electron microscope. The obtained particles had an approximately spherical shape, and their size was 40–70 nm (X-ray phase analysis, transmission electron microscopy). The introduction of Ho3+ cations to х = 0.15 into a CuFe2O4 spinel lattice led to a decrease in the average size of crystallites, an increase in the coercive force of nanopowders, and a decrease in excess magnetization and saturation magnetization. Synthesized CuFe2-xHoxO4 (х = 0, 0.1 and 0.15) nanopowders were magnetically hard materials with high coercive force.

A method has been developed for the separation of anthocyanins and anthocyanidins with high performance liquid chromatography (HPLC). Experimental designs were applied for multivariate optimization of the HPLC experimental conditions with using response surface methodology (RSM). Three independent factors, namely formic acid concentration, initial ratio of acetonitrile in gradient program and flow rate, were used to design mathematical models. The responses were resolutions of four peak couples which were the most difficult to separate including: pelargonidin-3-glucoside and delphinidin, delphinidin and peonidin-3-glucoside, peonidin-3-glucoside and malvidin-3-glucoside, peonidin and malvidin. Variance analysis proved a chosen model was highly fit and the RSM method yielded good results in improving separation of anthocyanins and anthocyanidins. The optimized HPLC parameters were as follows: C18 column (250 mm × 4.6 mm × 5 µm), mobile phase is FA 10 % and ACN used as a gradient; flow rate 0.8 mL.min-1. Using these optimum conditions, separation of compounds with good resolutions and a run time of less than 30 min were archived. The results for method validation satisfied the requirement of AOAC, linearity range from 0.2–10 ppm with R2 ≥ 0.9955, LOD from 0.05–0.1 mg/kg, RSD from 4.79–6.45 % and the recovery is from 85.4 – 109.6 %. The method was applied to determone anthocyanins and anthocyanidins in some fruits and vegetables samples with the content of anthocyanidins being from 5.74 – 218.27 mg/100g. Anthocyanins primarily concentrate in peel of fruits and vegetables, black bean peel contains most anthocyanins.

Ethnic minority migration in Vietnam is a unique type of migration. It is the migration of individuals, groups (families, clans, hamlets), communities of ethnic minorities (to villages, communes, districts, provinces, intra-/inter provinces), regions; the migration could be in the Northwest — Central Highlands direction, or could be rural — urban, rural — rural, urban — rural, rural — industrial zones migration. It could be cross border migration (to China, Laos, Cambodia, Thailand, Myanmar; to Middle East countries). These migration could take various forms: spontaneous migration (free migration), organized migration (planned migration) for reasons such as migration to take refuge, for marriage with foreigners, for economic reasons, for labor export, for familial reunion.

Introduction. An assessing of the sportsman's physiological reserve (PR) and its dynamics is important when planning and carrying out a training, forecasting sportsman's results. An importance of this problem increases in highperformance sports, and energy consumption sports. A complexity of solving of this problem is caused by the requirement of taking into account of the complex of the biomedical parameters and formation of an integral parameter. This parameter reflects functioning of various body systems which provide significant income to the sportsman’s result achievement. Objective. Development of the method and the system of PR assessing allowing complex investigation of the PR during the training process. Method and materials. For achievement of the aim the tasks were formulated and solved using methods of biomedical research and engineering, mathematical processing and analysis of the diagnostically valuable parameters. Results. The complex of the biomedical parameters reflecting sportsman’s body metabolism in condition of physical exercises is formed. They are the heart rate, the heart rate variability, the pulse frequency, the systolic and diastolic pressure, the respiratory rate, the blood saturation, and the stress index by Baevsky. It is important for PR assessing to assess parameters characterizing sportsman’s physiological reserves at the current moment and its dynamics. The circle diagram is proposed for taking into account of all mentioned parameters and its variation dynamics. The value of the integral PR parameter is an area of a polygon, which is obtained on the circle diagram using normalized values of the diagnostically significant parameters. The method of biomedical investigation of the sportsman and the method of PR assessing based on the complex of the body system parameters are developed. The scheme of assessing of sportsman's body physiological reserves before and after the training is proposed. The scheme allows to assess not only sportsman's body energy consumption during the training but also its recovery after the training. General structures of the biotechnical system and a structures of systems of picking up, registration, processing, and analysis of biomedical signals for assessing of sportsman's physiological reserves are developed. Special attention is given to the development of a wearable device for synchronous registration of the complex of biomedical parameters and algorithms of assessing of the diagnostically significant parameters of sportsman's body physiological reserves. Conclusion. The proposed method of sportsman's physiologic reserves investigation and the structure of the system with spatially distributed architecture allow sport medicine doctor and coach to assess an efficiency of sportsman's training process with respect to his potential capabilities, and efficiently control the training process.

At present time, megacities face acute problem of construction of tunnels for laying utility networks. In such large cities as Hanoi, Ho Chi Minh, there are still no solutions to the problem of laying technical pipelines, power cables, water supply and sewage pipelines. The paper describes the method of utility tunnel designing, taking into account rock composition and restricted construction conditions for each specific area, based on the use of small tunnel-boring machine. Using this method ensures reliability and economic feasibility of the tunnel construction project.

Cultural globalization is the fierce and unavoidable tendency that has powerfully influenced the culture of each nation or ethnicity, especially the cultures of developing countries. They are worried about the uniformity of the world culture, which will fade away cultural identity diversity. This paper analyzes some threat and chances of the globalization process and point out several solutions that Vietnam has applied and practiced to preserve cultural identity in the context of cultural globalization.

Background. Complex Au-Cu-U mineralization is found in the metamorphic rocks of central Vietnam in the zones of their contact with Triassic granite intrusions. It is localized in tectonic breccias and cataclasites, which affected Triassic granitoids and Precambrian metaskarn rocks. The greatest differentiation is observed for tectonically disturbed granites of the Hai Van complex and the metasomatically reworked zones of contacts of this complex with metacarbonate and metaultramafic rocks of the Kham Duc complex.Aim. To determine the mineral and elemental composition of complex occurrences of Cu, U and Au in Proterozoic rocks of the Kon Tum province of central Vietnam.Materials and methods. The work was based on the authors’ data obtained during fieldwork and analytical laboratory studies in the 2016–2019 period. The diagnostics of ore mineral composition was carried out using 60 polished sections. The chemical composition of ores was determined for 214 samples by ICP MS and for 374 samples by atomic absorption spectrometry at the Vietnamese Centre for Geological and Experimental Analysis in the city of Hanoi. The geochemical relationships of ore components were established by the method of multivariate statistical correlations.Results. The mineral composition includes pyrrhotite, pyrite, chalcopyrite, molybdenite, magnetite, martite, hematite, cubanite, marcasite, gold, xenotime, sphalerite, uraninite, chalcocite, covellite, goethite, malachite and limonite. According to the petrographic and petrochemical composition, the geological position and the data on isotopic age, the metamorphic formations of the Kham Duc complex can be considered as Neoproterozoic-Cambrian formations having experienced metamorphism in the Ordovician.Conclusion. A scheme of the sequence of mineral formation was outlined. ICP MS results of primary ores showed that, in addition to Cu, the formations under study contain concentrations of Co, Mo, U, Au, Zn, Ni, V, Y, La, and As. A positive correlation was found between Cu, U and Au. A model of hydrothermal ore formation was proposed.

The article substantiates the relevance of the inspection of overhead power lines by determining the mechanical loads of the conductors. The conductor sways under the action of external loads and variable internal mechanical loads. The conductor behaves in span like a pendulum. Using the inclinometric method, it is possible to determine the deviations of the conductor in space from its equilibrium position. Having restored the geometry of the conductor in the span of an overhead power line, mechanical loads can be determined. A model of the harmonic oscillations of the conductor in flight is derived to assess the mechanical loads of the conductor overhead power lines. This mathematical model is based on mathematical models of a flexible thread and a model of a physical pendulum. A conductor is a physical pendulum, where the conductor acts as the body, and in the role of the fixed axis of rotation, a straight line passing through the suspension points of the conductor. The developed model allows you to determine the arrow of its sag from the period of oscillations of the conductor in the span. The article considers algorithms for calculating the conductor sag arrows for two cases: the conductor suspension points are at the same height; conductor suspension points are at different heights. A theoretical calculation is given for a model of a span overhead power line with an estimate of the sensitivity of the developed model and its error in determining the sag of the conductor. Using the arrow of the conductor sag, you can restore its geometry, and hence the mechanical load of the conductor. Therefore, knowing the initial geometric parameters of the span of the overhead power line and the current period of the conductor’s oscillations, it is possible to examine its current state.

Object. The article presents the results of computer research, the purpose of which was to develop dynamic models of low-power twin-shaft gas turbine units (GTU) equipped with automatic excitation and speed regulators with predictive links. Methods. Setting up the regulators of the commissioned gas turbine requires complex calculations. The use of algorithms that make it possible to improve the classical regulators with minimal costs allows us to effectively solve the problems of their settings. These include prognostic algorithms that allow you to configure the automatic control system using one parameter - forecast time. The models presented in the article are implemented using the Simulink package of the MATLAB system. Results. The influence of prognostic algorithms on the quality of controlling the voltage and rotor speed of a gas turbine generator in the modes of connecting and dumping loads is studied. Studies have shown that increasing the coefficient of the amplifier of the auto-predictive speed regulator can significantly reduce overshoot and the transition process, and also has a positive effect on voltage regulation. Conclusions. The results made it possible to formulate the following conclusions: the use of prognostic regulators when connecting an additional load to the gas turbine allows you to remove the oscillation, reduce voltage dips, reduce the transient time by 2.5 s; with a sharp load shedding due to the use of prognostic algorithms, it is possible to completely remove the oscillation, reduce the overshoot of the rotor speed and overvoltage at the generator terminals, and also significantly reduce the transient time for speed compared to classical regulators; the use of prognostic algorithms allows us to obtain acceptable quality indicators of transients without the use of complex regulator tuning procedures.

Introduction. Increasing requirements for improving of information systems for ensuring navigation safety in coastal areas of marine waters determine the search of new engineering and scientific solutions. The creation of a passive coherent location systems (PCL), based on existing sources of electromagnetic radiation (in particular, global navigation satellite system (GNSS) signals) as radar illumination of the monitored space is of particular interest. During development and implementation of the systems, there are a number of problems related to the search of highly efficient processing algorithms, to the optimization of structure and functioning modes when the system is a part of a complex multi-position monitoring system in coastal areas. Aim. Rationale of the structure of bistatic PCL system with GNSS illumination signal, analysis of methods for increasing of the level of reflected signals, development of a general signal processing algorithm of the system receiver unit, formation of proposals for the creation of multi-position radar system (MP radar) for coastal areas navigation monitoring. Materials and methods. Mathematical modeling, theory of signals, methods of digital signal processing. Results. The structure of the bistatic PCL with GNSS illumination signal for monitoring in coastal areas of marine waters to ensure navigation safety has been developed. Methods for increasing the power level of satellite signals at the input of the receiving device have been proposed. General signal processing algorithm and the algorithm of CAF calculation in the bistatic PCL system using GPS C/A code satellite signal for sea surface coastal areas monitoring have been developed. Conclusion. The considered bistatic PCL system with GNSS illumination may be applied as a part of MP radar for monitoring in areas of heavy vessel traffic to ensure the safety, for operational control of marine operations in the high seas, for quick analysis of the situation at sea in an emergency.

This review describes the current situation on highly pathogenic avian influenza virus in 2019 and predicts the possible further spread of avian influenza in Russia. In 2019 outbreaks were reported among wild birds and poultry, as well as human infections with influenza viruses of the subtypes H5Nx, H7N9 and H9N2 in several countries. In 2019, only two outbreaks of highly pathogenic avian influenza H5N8 in Russia occurred. Both outbreaks were recorded in January at poultry farm in the Rostov Region. In addition, in May 2019 avian influenza virus of H14N7 subtype was isolated from a wild bird during the avian influenza virus surveillance in Tomsk Region. In June 2019, a strain of H13N2 subtype was isolated in the territory of Kamchatka Region, then, in August 2019, an influenza virus of H13N6 subtype was isolated in the Saratov Region. It was revealed that some strains of avian influenza virus isolated in Russia have a high degree of identity with strains circulating in South-East Asia. This was shown by the phylogenetic analysis of A/ H5Nx influenza viruses previously isolated in the Saratov Region and the Socialist Republic of Vietnam during the avian influenza virus surveillance. Thus, it was demonstrated again that the territory of Russia plays a key geographical role in the global spread of avian influenza virus.

The wide spread of various radio systems with phase shift keying, including multi-position (MPSK), is due to their high noise immunity and ease of construction of the transmitting and receiving parts of the equipment. In real equipment, additional differential (relative) encoding is used when implementing transmitter and receiver circuits and, accordingly, DMPSK signals are used. One of the ways to receive such signals is to use an autocorrelation demodulator built on a quadrature scheme. The paper studies the noise immunity of an autocorrelation demodulator of signals with differential phase shift keying in the presence of Gaussian noise, Rayleigh fades and harmonic interference in the radio channel. The statistical parameters of signals and interference in the inphase and quadrature channels of the autocorrelation demodulator are determined. For M = 2 and 4, analytical formulas are obtained for the probability of a symbolic error, conditional on the random phase of harmonic. It is verified that the formula at M = 2 without harmonic interference reduces to an expression known from the literature. The values of the unconditional probabilities of symbolic errors are obtained by numerical averaging. It is shown that at a low level of harmonic interference, Rayleigh fading has a dominant effect. With a large level of interference, the additional energy loss can be several decibels, and at M = 4 these losses are significantly greater than at M = 2.

Proverbs as a section of language are a folklore genre that contains much knowledge, wisdom, philosophy, behavior of nations. Research on proverbs themselves is always an interesting job attracting many scholars. More particularly, research on proverbs as tools by language-culture relationship perspective to deeply understand cultures is a much harder task. Using an interdisciplinary approach and typological method in Comparative cultural studies based on the data of more than 151 proverbs processed, the findings of this article will introduce some cultural features of Polish and Vietnamese people as well as East and West. It is just a channel to prove that research on proverbs can help research on culture to affirm the differences and similarities in thought and behavior. Accordingly, this will help the communication and cultural interchange, cooperation, and education better and more effectively.

The purpose of this paper is to contribute to further clarifying the characteristics of marine culture in the Northeast of Vietnam from the theory of cultural ecology. The research results of the article will also be a scientific basis to contribute to the study of Vietnam’s sea and islands from the science of culture. In order to carry out this research, the author uses an analytical-synthesis method, which is used to deeply understand the research object, combining a comparative approach to show the similarities and differences between the marine culture of Northeast Sea and some other areas in Vietnam. The author attaches special importance to the practical survey method: participating in cultural activities of residents of some localities in the Northeast Sea of Vietnam (such as Quan Lan Island, Co To Island, Cat Ba Island...), and conducting interviews with people for the purpose of truly describing phenomena related to marine culture. Previous studies in Vietnam only focused on describing the appearance. They stated the values of Vietnamese coastal culture and some localities in the Northeast, but the theory of approach in marine culture research is unclear. This research uses the theoretical framework of cultural ecology to affirm: the people in the Northeastern region of Vietnam with their thinking have created ways to adapt to the natural environment and always creating material and spiritual values that bring about the highest adaptation to nature to benefit their life activities. The research results of this article can be used as a reference for the culture of the islands in the Northeast in particular and the Vietnamese culture in general, including theoretical research on marine culture, as well as the analysis of marine cultural characteristics from cultural ecology theory

The article describes a bench for studying a system of a flow analyzer based on nuclear (proton) magnetic resonance (PMRA), used for the operational control of proton-containing multicomponent liquids (oils, fuels, oil and chemical products) and mixtures for viscosity and composition (concentration of asphaltenes and resins ) during oil production, oil preparation and use at energy facilities in the analysis of liquid fuel. This article also looks at the equipment that is used to control oil parameters with PMR-Relaxometry. Particular attention should be paid to the analysis of physical and chemical properties of oil components with the use of PMR. The use of sampling equipment for the purpose of controlling the rapid flow of oil parameters by the PMR method will eliminate phase separation in the sampling device and eliminate clogging with waste sediments, ensure efficient homogenization of the fluid flow in the sampler, as well as automate the measurement process.

In this paper described the switching power supply (SPS) unit and represented its importance for electronic circuits in electronic devices. SPS directly affect the operation of electrical circuits and electronic equipment. In particular, this paper describes its use in a portable proton-magnetic resonance (PMR) relaxometer. Especial attention is to the method of constructing the circuit, and also deals with the comparense of the SPS with a transformer power source. This article presents the structure of schematic diagram of the SPS. The SPS structure works without a transformer, which reduces the size of the system and increases overall efficiency. The proposed circuit structure is based on a push-pull controller, a high- frequency converter with an amplifier and a voltage multiplier circuit and a voltage stabilizer. The simulation and experiments confirm the proposed configuration of SPS.

High performance cleaning of a gas stream of solids of small diameter at small pressure losses in the device is one of key indicators at the choice of the abstersive device. In article, the rectangular separator developed by authors for efficient cleaning of gas emissions of boiler installations of solids is offered. The comparative analysis of a separator with the cyclone СN-11-400 is made. The dependence of hydraulic resistance coefficient from dimensionless geometric factor, it determined the global minimum and the ratio of beam separation elements, which are achieved with minimal energy costs. Results on the efficiency of the proposed separation device are obtained for different values of the length of I-beam elements. In particular, it is shown that with a decrease in the length of I-beam elements, the efficiency of separation of small-diameter particles increases. As a result of the numerical experiment, it was determined that when the length of I-beam elements is equal to 13 mm, the highest efficiency is achieved. At a volume flow rate of Q = 0.444 m3/s, the efficiency of the separator is on average 52% higher than that of the cyclone CN-11-400 when separating gas from particles up to 8 microns in diameter.

This article discusses the application of complex methods for detecting, recognizing, distinguishing borders and measuring various parameters of noisy, low-contrast, difficult-to-see images of space, air or ground objects. The problem of detecting, recognizing, distinguishing and measuring parameters of objects images (space or air objects, aircraft, ship, ground transport, people, coasts, etc.) is still among the very complex, completely unsolved radio engineering and telecommunications (“connected”) tasks. Currently, infrared (IR) direction finding, optical (laser location) direction finding and radar are used to detect, recognize, distinguish boundaries and measure the parameters of unknown objects against the background of external natural or artificial interference and noise. These methods have their own advantages and disadvantages, which do not always coincide. Therefore, it is of theoretical and practical interest to use them jointly, multifunctionally, or integrationally to identify objects against the background of external natural or deliberate interference and noise. When applying multifunctional methods for detecting, recognizing, distinguishing borders and measuring parameters of noisy, low-contrast images of objects against the background of external natural or artificial interference and noise. Digital processing of objects is mainly used now, which can be defined as a process during which an image is: modified to obtain a new one, which will be more convenient for research by a computer, or by the human eye; it is transformed into a certain set of characteristics and parameters visible and related to the observation area that are automatically analyzed by the computer, or directly presented to a person, taking into account pre-established criteria for developing a final conclusion about the studied object. Typically, the result of digital processing of the received signals is a new image that can be easily converted to analog form and directly observed on a computer display.

At present, the transfer of information is an integral part of technologies that are actively developing in the framework of the process called the Fourth Industrial Revolution. In this, space-satellite, satellite and other mobile wireless communication systems play an increasingly important role. Almost all of them include multiple access, which means a method of common resource division of the communication channel between subscribers (each mobile station has the ability to use a satellite retransmitter or the base station of a mobile wireless communication system to transmit its signals regardless of the operation of another station). Multiple-access communication systems are used for digital radio and television broadcasting in high-speed communication lines, in wireless local area networks, for data transmission in the microwave range, and also for communication with various mobile partners. In the radio transmitting and receiving paths of communication systems with multiple access, multiple signals are used (the sum of the power of the subscriber signals) with very complex types of digital envelope modulation, so they use wide working bands. With an increase in the quality of information transmission in mobile wireless communication systems, there are special requirements for powerful amplification systems (PAS) of receiving-transmitting tracts, which must have high efficiency and high output power, required bandwidth, network capacity, and linearity of message transmission channels. To achieve maximum efficiency in the PAS, the operating point of its amplifying element should be near the saturation region, on the main nonlinearity of the transfer characteristic. When multiple signals are introduced simultaneously into the PAS, it generates unfiltered intermodulation harmonics (IH). Intermodulation harmonics are formed due to the nonlinearity of the amplitude characteristics and the unevenness of phase-amplitude characteristics and due to the need to work with the highest efficiency of the PAS, which requires a shift of the operating point to the saturation thresholds of their amplifying elements. This, in turn, causes the appearance of IH. Since the harmonic oscillations IH actually represent noise for neighboring communication channels and are not theoretically filtered, an equalizer (otherwise an optimizer) of characteristics, is needed to reduce the level of these interferences in the output (Raman) spectrum of the PAS.

Statics of drying is based on the laws of interaction between the gas medium and the dehydration facility, which seek a thermodynamically equilibrium state. Jackfruit is a wet thermolabile material. With a static equilibrium between the product and the environment, the water content in a hygroscopic state depends on the type of the product, its energy, humidity, and a number of parameters, e.g. temperature and partial pressure of the vapor on the surface. The paper introduces graphical dependences of the activity of water of jackfruit slices on humidity at various ambient temperatures. The authors also give its analogy in semilogarithmic coordinates. It helped to define a range of humidity that determined the type of connection between the moisture of the object and the dry residue. The laws of the mechanism of heat and mass transfer are relevant in determining the dynamics of the dehydration process. Their study can help to intensify the process of moisture removal with rational operating parameters. The present study featured the equilibrium states in the system, which made it possible to find the driving force of moisture transfer and to evaluate the heat carrier potential, as well as to substantiate the values of the parameters and the environment during storage and transportation of the finished dry product. The value of relative moisture content in equilibrium was determined by isothermal sorption curves. The value depends on the pre-treatment of the drying object, the conditions of its contact with the external environment, as well as by the energy and type of relationship between the dry residue and the moisture. The empirical results were arranged in the form of graphical dependences, which made it possible to theoretically obtain their mathematical approximation. The equations of dependence between the equilibrium moisture content of the material and the relative humidity of the vapor-air medium included a lot of constants, which also needed to be determined empirically. The mathematical dependences approximate the isothermal sorption curves, i.e. the relationship between the product’s moisture and water activity indices. The dependences can be used to conduct a thermodynamic analysis of the sorption process and determine the free, bound, and internal energies of the process of moisture absorption by the capillary-porous object of study. The hygroscopic examination of jackfruit is also necessary when making design decisions for the rational implementation of technological operations, including the storage and transportation of dry jackfruit slices.