DOI: 10.26102/2310-6018/2022.36.1.025
The article considers the problem of modeling large data array processing in distributed information and telecommunication systems. The analysis of the problem, associated with the incorrect operation of the information system, is conducted. It is shown that distributed systems allow distribution of logic and data across multiple physical servers, which, with the correct allocation of resources and logic, makes it possible to reduce the risks of failures. It is demonstrated how the calculation of productivity loss percentage from a failure in one of the distributed information system components is carried out. A fragment of the diagram, outlining the options for the store information system application, is examined. If it is necessary to purchase physical servers when building an information system, then it is possible to calculate the coefficient of decrease in the performance of the information system in the event of a failure on one of the servers while ensuring the conditions for simultaneous operation of servers. The graph, illustrating the dependence of the performance change on the number of nodes that comprise the distributed network, is given. The analysis indicates that the cases when there are not too many servers have the greatest effect on reducing the risks from adding nodes to a distributed system. If a distributed system already consists of many different servers and any logic is duplicated on many of them, the risk reduction from adding an additional server will be negligible.
Keywords: distributed data processing, information system, modeling, information transfer, algorithm
DOI: 10.26102/2310-6018/2022.36.1.021
The paper discusses the issues of developing a method for visualizing the internal structures of the body, based on the restoration of the acoustic nonlinear parameter distribution. The process of occurrence and propagation of the second harmonic wave in tissues with high nonlinearity and attenuation is considered. The use of the relative acoustic nonlinear parameter in relation to the absolute nonlinear parameter of the medium is proposed. To solve the problem of restoring the distribution of the relative acoustic nonlinear parameter in biological media, an equation is obtained that eliminates the necessity to measure changes in absolute pressure values for both the fundamental frequency wave and its second harmonic. Mathematical expressions are derived that enable accounting for the attenuation processes for the fundamental frequency and for its second harmonic, taking into consideration the influence of the medium in which the object under study is placed. Expressions for determining the relative acoustic nonlinear parameter are acquired. Drawing on these expressions, the construction of a visualization system, utilizing algorithms for restoring the distribution of the acoustic nonlinear parameter in the cross section of a biological object, is presented. The main advantage of these equations is that there is no need to identify changes in the absolute amplitudes of the fundamental frequency and second harmonic waves. The outlined methods for calculating the nonlinear characteristics of biological tissues make it possible to simplify the technical implementation of ultrasound imaging systems.
Keywords: ultrasound imaging, nonlinear parameter, second harmonic, nonlinear acoustics, structure of biological objects
DOI: 10.26102/2310-6018/2022.37.2.014
In the digital era mobile devices are becoming the main instrument of human social interaction. With the growing popularity of instant messengers, the role of chatbots in the mobile environment appears to be more and more significant. Intelligent interactive chatbots are often used in mobile applications and help improve the interaction between companies and their customers, which ultimately increases customer loyalty to that organization. Chatbots allow companies to communicate with customers on an individual basis, without involving employees and thereby saving time, money, and human resources. The majority of chatbots works with scripted algorithms and they are not universal. This is due to the simplicity and speed of development. However, in this case, there is a risk of missing many choices in the decision tree. Chatbots based on neural networks can solve this problem, but it should be taken into consideration that both of them have a drawback – long processing of messages and feedback. In the context of the scenario approach, this is caused by long branch transitions. For neural networks, complexity arises because of the feedback processing algorithm. In that instance, the application of the service will not be justified, customer loyalty to the organization will deteriorate. In this connection, the article discusses an alternative approach to creating chatbots with the aid of neural network technologies and text representation methods, which avoids the problems described above. As a means of chatbot design, the following technologies were utilized: Python 3.6, genism libraries, sklearn, scipy, pandas, word2vec and doc2vec technology. The article also describes a way to accelerate chatbot feedback and training using KD-Trees.
Keywords: neural networks, chatbot, word2vec technology, messengers, word embedding
DOI: 10.26102/2310-6018/2022.36.1.001
Currently, the problem of collective decision-making is one of the most relevant in the organization of effective management in social and economic systems. One of the main issues in the theory of expert assessments is the assessment of the group solution quality. The article discusses the matters of assessing the socio-economic indicator by independent experts. The centered random variables sums value of individual estimates is accepted as the error of group estimation. The situation is examined when the values of the indicator have an arbitrary distribution with known and unknown parameters. Two algorithms have been developed to determine the required amount of experts depending on the accuracy and reliability of the assessment. The first algorithm is used to find the confidence interval of mathematical expectation when the variance of the indicator is not specified. In this event, an iterative process is undertaken to ascertain the volume of representativeness for the confidence interval of variance with a given accuracy and reliability. The second algorithm is employed to construct a confidence interval for variance when the number of experts is more than three. The important task of quantifying the proportion (percentage) of possible errors within a predefined interval in measuring the indicator has been solved. An econometric model is designed for the Laplace function. The case of determining the number of experts to evaluate an indicator having a uniform and exponential distribution over a given interval is considered. An example of the practical implementation of the devised method is shown.
Keywords: approximation, significance level, estimation accuracy, laplace function, econometric model, expert, estimation, probability distribution
DOI: 10.26102/2310-6018/2022.36.1.002
The paper describes a method for adapting the educational process in adaptive role-playing learning games using dynamic content matching of nonlinear learning and game scenarios. The training scenario and the game scenario, associated with it, are represented by structurally ordered spaces. The mechanism of dynamic content matching of nonlinear training and game scenarios implemented in the game is based on the activation of predefined game events in relation to the plot path chosen by the player. Triggers are assigned to each visible and invisible object of the game world in conformity with the constructed knowledge space. When a character enters a game situation tied to the trigger's scope, a system of dialog boxes is enabled to complete the objective, set by this game situation. The player dynamically builds their game scenario depending on the choice of a strategy for mastering the knowledge space and performing the corresponding game tasks while the method of dynamic content matching, executed in the game, ensures the development of the entire space in terms of any strategy formed by the player. The means of the method employment in the Cammi learning role-playing game for studying object-oriented programming and the C++ language is defined.
Keywords: learning game, adaptive learning game, training course, adaptation model, adaptation method, nonlinear scenario, knowledge space
DOI: 10.26102/2310-6018/2022.36.1.024
Nowadays, the problems of the economy decarbonization and the transition to renewable energy sources are becoming more relevant. Hydrogen, above all, is among the decarbonated gases, the use of which is considered the most promising. It is regarded not only as an energy carrier but also as a means of storing excess energy, produced by renewable sources. The steam methane reforming, at the outlet of which a hydrogen-enriched gas stream is obtained, is deemed to be the most well-developed scheme. Adsorptive gas separation systems are widely used to extract hydrogen from the steam reforming gas. Mathematical modeling plays an important role in the design of adsorption gas separation plants. Optimization and control systems synthesis can be carried out with the help of a mathematical model for the process under review. The article proposes a mathematical model for the hydrogen extraction technological process by the pressure swing adsorption method employing a 6-beds gas separation unit. For the numerical solution of the mathematical model equations, the method of lines was applied, which converts partial differential equations to a system of ordinary differential equations. The integration of resulting equations system was undertaken with the aid of the Runge-Kutta method with automatic step selection. The results of numerical simulation calculations of the system dynamic operating modes are given. It is concluded that the proposed mathematical model for the adsorption process of gas separation is allowed for solving the problems of numerical simulation studies, optimization and control systems synthesis
Keywords: adsorbent, adsorber, adsorption, activated carbon, regeneration, zeolite
DOI: 10.26102/2310-6018/2022.36.1.014
The article shows the methodology and results of laboratory tests to determine the performance indicators of operators with combined multi-band images, namely, video and thermal images acquired from the same object at the same scale and with the same sweep parameters. The images were presented in two versions. In the first one, tests were carried out to detect specified objects in a combined image from video and thermal imaging cameras. In the second one, the same detection procedure was undertaken on interpolated images, when each pixel of the resulting image contained information from both sensors. The relevance of the work done lies in obtaining the probabilistic characteristics of a given object detection from simply superimposed images and images subjected to spatial interpolation, which confirms the increase in the information content of the interpolated images, but in practical terms. The tests were run with the involvement of a large number of operators, each of which worked with images only once. As a result of the tests, data were collected on the time of object detection by each operator and the probabilistic characteristics of detection were calculated. A comparative analysis of the findings was carried out in order to ascertain the efficiency of operations with interpolated and non-interpolated images. The sufficiency of the conducted experiments is proved.
Keywords: laboratory tests, combined images, interpolated images, detection time, probabilistic characteristics of detection, practical increase in information content
DOI: 10.26102/2310-6018/2022.36.1.013
One of the most important problems of creating 3D models with the aid of three-dimensional scanning systems is automatic processing to eliminate noise obtained due to the application of scanning devices with insufficient accuracy. The aim of the study is to develop a fully automatic approach for solving the problem of denoising in polygon meshes acquired after three-dimensional scanning. The principal method to overcome this is the application of neural networks that allow processing of polygon meshes to be performed automatically. The article presents an overview and comparative analysis of existing methods of denoising in polygon meshes. The mathematical formulation of noise elimination problem is provided. The description of the algorithms used to prepare data for neural network training is given. The method of polygon meshes filtering by the means of a bilateral filter, the method of principal components for reducing the dimension of data, the k-means clustering algorithm, the algorithm for updating vertex positions by updated face normals are employed. Details of a fully connected feedforward neural network implementation are described. The results of the study are outlined. The analysis of the findings is carried out utilizing the quality metrics of the Hausdorff distance and the average value of the angle between the normals of polygon meshes with and without noise.
Keywords: neural networks, data science, polygon meshes, mesh denoising, three-dimensional scanning, bilateral filter
DOI: 10.26102/2310-6018/2022.37.2.002
Making and analysing fire incidence forecasts is the issue which is in the focus of the attention of the supervisory activity directorate of the Ministry of the Russian Federation for Civil Defence, Emergencies and Elimination of Consequences of Natural Disasters because it concerns safety of human life and, thus, the tasks of solving this problem, and therefore planning and optimization of unit personnel. At the same time, about 30% of the control measures total number, carried out by fire supervision authorities, pertained to scheduled inspections. This article demonstrates the correlation between fire dynamics forecasting and scheduled inspections and determines the magnitude of the lag or delay in conducting scheduled inspections in relation to the number of fires. The mathematical and statistical model is based on the example of statistical data on the fire incidence in the Nizhny Novgorod region and the Russian Federation from 2010 to 2020. To define and address this problem, the mathematical apparatus of time series theory was used, in particular, the method with distributed lags - the Almon technique. The findings allow us to conclude that mathematical models with distributed lags, performed by means of the Almon technique, can be employed to predict fire incidence in the EMERCOM of Russia system, as well as to schedule inspections of the state fire services of the EMERCOM of Russia and formulate proposals for optimizing the personnel of the EMERCOM units.
Keywords: EMERCOM of Russia, fire incidence, scheduled inspections, mathematical and statistical forecasting model, time series, model with distributed lags, the Almon technique
DOI: 10.26102/2310-6018/2022.36.1.012
The developed information training system contains visual, generalized, structured material on mechanical stability, accident rate as well as ecological and biological features of the main woody plant species used in the landscaping of Donetsk: systematics, biology and ecology, biogeography, representation in the environment of Donetsk, mechanical stability and accident rate, crown shape, crown structure, wind resistance, resistance to anthropogenic factors, critical age in the environment of Donetsk, the presence of a cross-section/core sample in the xylotheque, recommendations for gardeners, landscaping concepts, illustrations. The information system is educational in nature and allows the researcher to quickly and visually familiarize themselves with the ecological and biological features of the growth and development of woody plants in the steppe zone, drawing on the example of the industrial city of Donetsk, as well as with the methodology of monitoring studies to assess the mechanical stability of woody plants, to learn to analyze the dependences of mechanical stability parameters for 18 species of woody plants growing in the Donetsk environment and to find and accurately identify the positive and negative aspects of employing various woody plant species for the purpose of landscaping in an industrial city. At the end of the training, there is an opportunity to evaluate the acquired knowledge and skills through interactive testing for each section. The described information system summarizes the results of Russian and foreign studies on the ecological and biological characteristics of the species presented and supplements them with information about the features of growth, physical and mechanical properties of wood, mechanical resistance to dynamic (wind) and static loads (glaciation, snow sticking, etc.) in a large industrial city. The information system is aimed at high-quality training of future specialists in the field of biology and ecology, contributes to the implementation of the results obtained in the educational process (as a study guide for students and postgraduates of biological universities). It can also be utilized in environment state monitoring and in assessing the accident rate of woody plants.
Keywords: information system, algorithm, distance learning, mechanical stability, ecology of woody plants, tree stability, landscaping concept, selection of species
DOI: 10.26102/2310-6018/2022.37.2.004
In the article, errors that occur when using the most common current sources with low output resistance (voltage amplifiers), feeding coils of biological object modification sets by means of a magnetic field are identified with the aid of the proposed modeling methods. To exemplify the operability of the models under consideration, oscillograms of changes in the magnetic field induction time in the coil of the set, when it is powered by a voltage amplifier having a low output resistance, are given. As an alternative, it is suggested to employ a developed and assembled specialized current source with a high output resistance, voltage-controlled (ITUN), designed to work with an inductive load. The magnetic field, generated by the coil of the set, fully corresponds to the current, flowing through it from the current source. The article describes the layout of such current source, as well as a high-speed system for limiting the input signal, which enables the protection of the circuit power elements from overloads that occur when working on an inductive load. As an illustration of the effectiveness of the magnetic field creation method, the oscillograms of the change from the induction time of the magnetic field produced in the coil of the set, when it is powered from the current source layout, are presented. In order to implement the layout of the magnetic set and monitor the state of the magnetic field being measured, a high-speed magnetometer was additionally designed and built, which allows reading data in real time.
Keywords: magnetic set, ITUN, magnetometer, magnetic field, modification of biological objects
DOI: 10.26102/2310-6018/2022.36.1.011
The article discusses and substantiates the principle of multi-range images combining and processing based on matrix devices with charge coupling. The developed principle is proposed as an alternative to the software implementation of the task of multi-range images combining and processing. The analysis of existing methods of combining multi-range images is carried out and the insufficiency of these methods in terms of increasing the resulting image information content is confirmed. The method for images combining and processing with a view to enhancing the information content, which is performed by means of digital methods, is considered. The possibility and prospects of the specified problem employment with the aid of discrete-analog systems, namely, the basis of matrix devices with charge coupled, have been affirmed. The principle of a two-stage impact on charge packets, which form image pixels in matrix devices with charge-coupled devices, is suggested with the aim of dividing them in specified proportions, indicated in the digital method, and introducing the necessary division parts into adjacent storage cells. The application simplicity of the procedure for dividing and moving parts of the charge packets by changing the voltages on the phase buses of the matrix device with charge coupling is shown. The transfer characteristic of the charge coupled matrix device in the outlined mode is determined analytically. The coefficient of the transfer characteristic squareness is ascertained.
Keywords: charge coupled matrix device, images, processing, charge packets, charge pack division
DOI: 10.26102/2310-6018/2022.36.1.010
In this article, suggestions are given for modeling the processes of cell separation by the magnitude of magnetic susceptibility. On the basis of the proposed model, an operating separation unit was created, and its description was given. To improve the efficiency of the operating separation unit, in comparison with existing equivalents, design solutions were introduced. It has been experimentally established that a lattice, consisting of rods of soft magnetic steel, which is a spatially periodic polygradient structure, can secrete cells of various magnetic susceptibility when the magnitude of the external magnetic field, applied to this structure, and the constant flow rate of the working medium, pumped through it, change. Additionally, we have also developed a technique for isolating cells with different magnetic susceptibility by means of the operating unit. The derived method makes it possible to acquire "spectra" of the magnetic susceptibility of cell samples. After the calibration of the unit, it is possible to predict the expected results of the cell separation analysis. The efficiency of the devised separator rises with an increase in the number of rows (rods) in the periodic structure. The accuracy of the findings depends on the pumping time. With weak fields, the shutter speed needs to be accelerated. Non-magnetic or weakly magnetic biological cells may remain in the swirl zones. This phenomenon negatively affects the quality of the samples obtained, especially with weak magnetic fields.
Keywords: separator, magnetic field, biocells, magnetic susceptibility, high-gradient magnetic separation, method of biocell separation
DOI: 10.26102/2310-6018/2022.36.1.009
The article completes a series of three original publications, related to the modeling of seismic risks in the geological environment in design and construction of critical infrastructure facilities. The preparation of the series is aimed at achieving the goal of finding a quantitative correspondence of seismic risks, calculated according to mathematical models, with seismic impacts, regulated in the Seismic building design code (SP 14.13330.2018). For this purpose, the tasks are solved: in the first article the criteria for choosing test territories are justified, and the territory of Armenia and neighboring states is selected as a test region; in the second - by the example of the test area, an assessment of the probabilistic seismic risk was performed with the help of specially created mathematical models at the regional and local scale levels; in the third - mathematical models and software were developed to determine the compliance of the calculated seismic effects, regulated by the design code with the values of the probabilistic seismic risk, obtained using mathematical modeling. The final article concludes that the prospects for further research are associated with the construction of a new seismic intensity scale of possible earthquakes as a function of the calculated probabilistic seismic risk and the depth of the possible earthquake source, as well as the creation of a special normalization scale that enables to transfer the probabilistic seismic risk, calculated for any region, into intensity as a measure of shaking in points of a single macro seismic scale. The construction of similar scales is highly relevant for the calculated kinematic parameters, currently employed in the design code – peak acceleration, displacement velocity and the actual displacement of the ground.
Keywords: modeling, seismic risk, geological environment, test area, building codes and regulations
DOI: 10.26102/2310-6018/2022.36.1.008
The article presents the description and results of the implementation of regional and local mathematical models, created to address the problem of estimating stresses, deformations and displacements in the geological environment. In the regional model, the main factors, causing the occurrence of stresses, displacements and deformations of the geological environment, are the inhomogeneities of the anomalous gravitational field distribution in isostatic reduction and the features of the Moho surface relief. To describe a local deterministic model, which is employed to estimate the stress-strain state of a three-dimensional elastic space, the displacement equations, solved by the Galerkin method, are utilized. Computer versions of models, provided with digital information, open up fundamentally new opportunities for the construction sector in carrying out the tasks of assessment, analysis and forecasting of the geological environment seismic characteristics. Mathematical models and calculations, obtained with their application, are a reliable basis in the field of design and construction of buildings and structures under difficult geological conditions. Survey work and the construction itself require significant material, technical and financial resources. It is concluded that the use of modern digital technologies for assessing, analyzing and predicting seismic risks reduces unjustified losses and develops the intellectual component of the methods exploited as well as methods of design surveys.
Keywords: construction, computer modeling, geological environment, stress-dynamic state, seismic risk
DOI: 10.26102/2310-6018/2022.36.1.007
The article considers the model for solving the problem of seismic risk quantitative correlation, calculated on the basis of modeling, with seismic impacts regulated in the Seismic building design code. The paper is the first part in a series of scientific publications on the subject. For the first time, it substantiates the criteria for selecting test territories, describes the methodology for verifying the adequacy of seismic risk assessment models, characterizes a probabilistic model of energy transitions in a stress-strain geological environment, and presents an approach to evaluating model parameters through the potential energy transformation indicators of the stress-strain geological environment. The content of the other two parts of the series is indicated. Armenia and neighboring states meet the criteria for choosing a region for practical testing of the model: high seismicity, the necessary information base and proven adequacy of the seismic risk model application at all deep levels of the earthquake epicenter locations. The method of the adequacy verification of the seismic risk assessment mathematical model, using the Student's criterion, is examined in detail. It is shown that when estimating the parameters of transitions between states of the model, described by the Kolmogorov equations, it is important to take into account both the influence of regional fields (anomalous gravitational field) and local fields (modern tectonic movements). Thus, a rationale is provided for employing two deterministic models – regional and local - for practical evaluation of stresses and displacements in the geological environment.
Keywords: model, seismic risk, stress-deformed geological environment, test territory, criterion, regional and local geophysical fields
DOI: 10.26102/2310-6018/2022.36.1.016
The task of detecting and observing targets has always been relevant. One of the most important objectives of radar development is to improve target recognition. There are two ways to achieve this – firstly, the installation of more powerful radar systems, which is very expensive and hard to implement under the conditions of limited space, for example, on airplanes; secondly, the quality of the received signal can be enhanced with the aid of mathematical methods, which allows to considerably save on setting up additional equipment. One of the main problems of recognition is the fact that the number and angular location of targets can be difficult to determine from the signal received by the radar system. This problem can be addressed by employing a wavelet transform. This method enables to overcome the Rayleigh criterion, that makes it possible to obtain an angular super-resolution (to surmount the classical diffraction limit of the spatial resolution of an image focused by a lens that is less than half the radiation wavelength). The article uses a mathematical model of a radar station to present the results of numerical experiments to achieve super-resolution by means of algebraic methods at a significant noise level. We examine the suitability of utilizing different types of wavelets, namely the Haar wavelet, the symmetric Haar wavelet, and the Wave wavelet.
Keywords: wavelet transform, computer modeling, super-resolution, target search, simulation model
DOI: 10.26102/2310-6018/2022.36.1.006
The employment of machine learning systems is an effective way to achieve goals, operating with large amounts of data, which contributes to their widespread implementation in various fields of activity. At the same time, such systems are currently vulnerable to malicious manipulations that can lead to a violation of integrity and confidentiality, which is confirmed by the fact that these threats were included in the Information Security Threats Databank by the Federal Service for Technical and Expert Control (FSTEC) in December 2020. Under these conditions, ensuring the safe use of machine learning systems at all stages of the life cycle is an important task. This explains the relevance of the study. The paper discusses the existing security methods, proposed by various researchers and described in the scientific literature, their shortcomings, and prospects for further application. In this respect, this review article aims to identify research issues, relating to machine learning system security, with a view to subsequent development of technical and scientific solutions, regarding the matter. The materials of the article are of practical value for information security specialists and developers of machine learning systems.
Keywords: machine learning, malicious impact, integrity, confidentiality, security