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Научный журнал Моделирование, оптимизация и информационные технологииThe scientific journal Modeling, Optimization and Information Technology

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issn 2310-6018

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metadata of articles for the last 2 years

Formalization of a multi-criteria transport task with time constraints

2024. T.12. № 2. id 1557

Belykh M.A.

DOI: 10.26102/2310-6018/2024.45.2.027

The article considers the mathematical formulation of a multi-criteria transport problem with time constraints. The criteria in it are the cost of transportation, their importance and the time spent on transportation. A feature of this task is the presence of time constraints, such as time windows for customers and the duration of stay of vehicles on the road. As a solution to the multi-criteria problem, the selection of Pareto optimal points is proposed, since this optimization method has a wide range of tasks to apply. The formulation of pareto optimization and the definition of pareto optimality are given. Pareto optimization methods are considered: the lexicographic method and scalarization, the varieties of which are the method of ε-constraints, which is based on the gradation of optimization criteria in descending order of their importance, and the method of linear scalarization, the mechanism of which is based on combining all optimization functions into one. Using the example, we consider the reduction of a formalized multicriteria transport problem to a form suitable for scalarization. The definition of pareto efficiency seems acceptable for the implementation of its mechanisms as part of an adaptive decision support system aimed at solving optimization problems in various fields and operating with heuristic algorithms.

Keywords: optimization problem, multi-criteria transport problem, time-bound problem, pareto optimization, pareto optimality, decision support systems

Numerical method for solving the problem of rational location of technical means of traffic management

2024. T.12. № 3. id 1556

Arutiunian M.A.

DOI: 10.26102/2310-6018/2024.46.3.021

The article presents one of the scientific results obtained by the author during his dissertation research  a combined numerical method for solving the problem of rational placement of technical means of traffic management, based on the use of the gradient descent method together with the Newton-Raphson method. One of the pressing problems of the development of a modern city is raised, which is the formation of a convenient and safe road and transport infrastructure. According to statistics, in the Russian Federation every year almost 20% of the total number of road accidents occur in collisions with pedestrians outside pedestrian crossings. As one of the solutions to the problem under consideration, it is proposed to install technical means of organizing traffic, in particular pedestrian crossings, on those streets on which they are either irrationally located or absent altogether. A mathematical model for the rational placement of technical means of traffic management has been developed and a numerical method for its solution has been proposed. It is noted that the combined numerical method proposed by the author allows one to quickly and accurately find the optimal parameters for the developed mathematical model, which helps to improve its performance and accuracy. It is generalized that the joint application of the considered numerical methods is a fairly effective way to solve the problem.

Keywords: numerical methods, gradient descent method, newton-Raphson method, technical means of traffic management, road safety

The Markov model of cyber attacks and its application to the analysis of information security in automated systems

2024. T.12. № 2. id 1554

Trapeznikov E.V. Magazev A.A. Kasenov A.A.

DOI: 10.26102/2310-6018/2024.45.2.011

The paper presents a description of the Markov model of cyber attacks as a method for analyzing information security in automated systems. Based on the presented model, the work provides a description of two safety metrics - the average time to safety failure (the average number of transitions between states in the corresponding Markov chain before it first enters one of the absorbing states) and the average risk in case of safety failure (the sum of the products of damages during the implementation of each from cyber attacks to the corresponding probabilities of these cyber attacks). An algorithm for estimating input parameters is given based on the relationship between the threat and vulnerability databases CVE, CWE and CAPEC. The relationships described in the work allow us to calculate the vector of probabilities of the occurrence of cyber attacks and the vector of damage from cyber attacks, which are formed as input data for the security assessment model. The paper also addresses the problem of numerical estimation of parameters through CVSS metrics. The study demonstrates that the vector of probabilities of repelling cyber attacks and the vector of probabilities of “delays” of cyber attacks can only be obtained using the method of expert assessments or statistics. The work also provides a description of the developed software product, which allows one to assess the security of an automated system over a given period of time.

Keywords: security metrics, CVSS metric, CVE, CWE, CAPEC, cyberattack model, data collection algorithm, automated system, markov chain, expert assessment method

Information and measuring system of the pneumatic actuator of an industrial robot of specialized purpose model MP-11

2024. T.12. № 2. id 1553

Sandler I.L. Ivanov D.V. Portnov A.A.

DOI: 10.26102/2310-6018/2024.45.2.026

One of the most important tasks faced by developers of pneumatic automation systems is to reduce the time of analysis and design at the research stage. The use of specialized software makes it possible to significantly improve the operation of pneumatic automation systems. Simulation of pneumatic robotic manipulators allows you to identify vulnerabilities, optimize control processes, conduct virtual tests of various work scenarios, which will help improve planning and management, while achieving significant improvements in system performance and reliability. The article presents an information and measuring system for the pneumatic drive of the robot (manipulator) links for specialized industrial purposes of the MP-11 model in the form of a simulation model, which is implemented by the method of simulation of pneumatic systems on the FluidSIM-P (FluidSIM Pneumatic) package of the Festo company. The result of the operation of the information and measuring system are graphs of transient processes of movement of the rods of pneumatic cylinders, which adequately describe the real operating mode of the pneumatic actuator of the manipulator MP-11. The materials of the article are of practical value for specialists involved in the design and analysis of automation systems. In addition, the results of the article may be useful for students and researchers studying the field of automation and system design. Anyone interested in the application of automation technologies in various fields will find valuable information in the article for their work and research.

Keywords: information and measurement system, robot, MP-11, simulation model, pneumatic circuit, transients, fluidSIM-P, pneumatic

Protection against multiple memory faults

2024. T.12. № 2. id 1551

Lepeshkina E.S.

DOI: 10.26102/2310-6018/2024.45.2.025

The problem of multiple faults in the memory chips of on-board equipment of spacecraft as a result of the impact of individual nuclear particles in outer space is considered. A review of the literature showed that the danger of multiple failures is real and will increase as technological standards for the design of electronic components decrease. Double multiple faults are currently the most pressing threat, as they are caused by charged particles with relatively low energies. Double faults can be adjacent or non-adjacent. Adjacent double faults are caused by the simultaneous action of a single nuclear particle. Non-adjacent faults are the result of the accumulation of single failures that occurred at different times in different storage cells of the same memory word. Under certain conditions, the occurrence of double non-contiguous errors can be avoided. To protect against double adjacent errors, correcting codes are used. These codes are relatively new and there is no general description of their construction. These codes are guaranteed to correct single errors and double adjacent errors, but have a significant probability of erroneously correcting a non-adjacent double error. But when moving to practical use, it is necessary to determine the requirements for the type of check matrix for these codes, to find a general algorithm for their construction for different memory word lengths, with low redundancy and high performance, provided that the correcting abilities of the code are subject to the requirements of detecting and correcting only single and double adjacent errors and no additional ones.

Keywords: single memory failures, single and multiple faults, double faults, frequency of multiple faults, measures to protect against multiple failures, double error correction codes

Mathematical model of the channel for measuring mechanical load on an insulator

2024. T.12. № 2. id 1550

Nepomnyashchiy V.Y. Panarin V.M. Maslova A.A. Ryabov P.E. Prokopchina S.V. Kochkarov A.A.

DOI: 10.26102/2310-6018/2024.45.2.024

The relevance of the study is due to the fact that an important factor in the reliable operation of overhead power lines is the proper operation of insulator strings, and damage to the insulator strings’ insulation can lead to an increase in leakage currents, energy losses, including emergency situations when insulators are damaged. Also, adverse weather conditions such as ice, snow, rain, fog, and strong wind can lead to additional losses of electricity. In this regard, this article is aimed at describing a new mathematical model of the channel for measuring the mechanical load on the insulator to assess the technical condition of the insulators, which is implemented as a separate block of the information-measuring system for remote monitoring of overhead line insulators, and provides the control center operator with up-to-date information about the current condition insulators, and also allows you to reduce the number of emergency situations through timely repair or replacement of insulators. The leading method in constructing a mathematical model of a channel for measuring the mechanical load on an insulator is to consider the static load with the prospect of assessing the processes of ice formation on the wires of an overhead power line, which makes it possible to record the dynamics of the increase in the mechanical load on the insulator (fixation of ice formation), as well as without unnecessary labor costs and time resources create an easy-to-use digital model of the energy system, which provides the opportunity to implement the structure, state and operation of a real energy system with sufficient efficiency, completeness and reliability. The article presents a sequence of measured values of the mechanical load sensor on the insulator when quantized in time, which are then compared with the value of the static load on the insulator, determined by the weight of the wire on the span of overhead power lines, and as a result, an assessment of the increase in the mechanical load on the insulator is made and the formation of ice is recorded on overhead lines. The materials of the article are of practical value for operational services of electric grid companies.

Keywords: remote monitoring, overhead power line, insulator, diagnostics, mechanical load, channel

Approaches to predicting changes in the state of supporting components of an information management system

2024. T.12. № 2. id 1549

Shevnina Y.S. Ryabov P.E. Prokopchina S.V. Kochkarov R.A.

DOI: 10.26102/2310-6018/2024.45.2.023

The article presents approaches to predicting the dynamics of the state of supporting components of information and control systems using the example of modeling the power system of a manufacturing enterprise. A method for modeling other types of supporting components based on the proposed approaches is considered. Modeling the state of the power system of a manufacturing enterprise is based on its representation in the form of a set of T-shaped cells consisting of resistance, capacitance and inductance. Forecasting changes in the state of the supporting components of the information and control system is carried out using a multilayer feed-forward neural network, taking into account nonlinear factors determined by the external and internal state of the production environment. Environmental parameters, data on depreciation of actuators and equipment, and regulatory production requirements are used as independent variables, and the power of the enterprise's energy system is used as a dependent variable. In this case, the power calculation is carried out on the basis of the described power system model using T-shaped cells. The model was trained on the basis of accumulated data. The obtained results of modeling the state of the supporting components of information control systems show that using a feedforward neural network model with one hidden layer and six nodes in it to predict the dynamics allows one to obtain an accurate power forecast taking into account various nonlinear factors. Experimental data are presented that prove the effectiveness of the approaches proposed by the authors for predicting the state of supporting components.

Keywords: information and control systems, state forecasting, nonlinear factors, power systems, feedforward neural network

Modeling the scattering of electromagnetic waves on structures in the form of a cube

2024. T.12. № 3. id 1548

Preobrazhensky A.P. Lvovich Y.E. Avetisyan T.V. Preobrazhensky Y.P.

DOI: 10.26102/2310-6018/2024.46.3.006

To date, among the various applied tasks in electrodynamics, it is possible to note the development of various approaches aimed at evaluating and studying the scattering characteristics of various electrodynamic objects. Among them, three-dimensional objects can be distinguished, which include flat surfaces and angular structures. Their contribution to the levels of electromagnetic fields in certain directions can be quite noticeable. In order to correctly solve the problem of scattering of electromagnetic wave scattering characteristics, it is necessary to rely on appropriate methods. At the same time, it is necessary to minimize possible errors, but the three-dimensional problem in question needs to be solved in a relatively short time. In this paper, the construction of a technique related to the determination of the scattering characteristics of a structure in the form of a cube is carried out. This is due to the fact that such structures are part of a large number of modern technical facilities, this must be taken into account during their design. To solve this problem, the method of integral equations was chosen. The results of the simulation are presented. A comparison with experimental data is carried out, and it is shown that the solution converges. A comparison with the characteristics of the Huygens cube is also carried out.

Keywords: numerical simulation of scattering, diffraction of electromagnetic waves, cube structure, integral equation, huygens cube

Classification models of the adaptive potential of a living system

2024. T.12. № 2. id 1547

Petrunina E.V. Safronov R.I. Pshenichny A.E. Filist S.A. Shehine M.T.

DOI: 10.26102/2310-6018/2024.45.2.010

As a result of the research, a method for classifying the adaptive potential of the human body was developed. The method is based on the use of data obtained by conducting a functional test associated with the Heaviside function, through which a model of the transition process in a living system is obtained. Representing a living system as quasi-linear, based on its impedance model, the spectral characteristics of the living system are obtained, on the basis of which descriptors are formed for the machine learning model. To obtain an impedance model of a living system, a three-phase experiment technique is proposed. The three-phase experiment technique consists of modeling the Heaviside function in the process of performing a bicycle ergometer functional test at three levels of the functional state of the human body. This allows us to calculate descriptors for the three “branches” of the adaptive potential classifier. The adaptive potential classifier includes a driver for constructing a linear impedance model of a living system, a descriptor generator, and a decision-making module. As a linear impedance model of a living system, the amplitude-phase-frequency characteristic of a four-terminal network is used, constructed from the transient characteristic of a model of a living system, and the descriptors are calculated using the Voight impedance model, which is adequate to the experimentally obtained amplitude-phase-frequency characteristic of a model of a living system. The quality indicators of the dichotomous classifier of adaptive potential were assessed on an experimental group of undergraduate and graduate students, divided into two classes using an indicator of the activity of regulatory systems. They showed that the level of true positive and true negative results when classifying unknown examples satisfactorily corresponds to expert estimates. This allows us to recommend it for use in practical medicine, for example, in biotechnical rehabilitation systems, sports medicine, as well as for monitoring the dynamics of the patient’s functional state during treatment.

Keywords: adaptation potential, transient response, impedance model, classifier, neural network, algorithm

A method for automated design of an exoskeleton taking into account the user’s anthropometric data

2024. T.12. № 2. id 1545

Драгунов С.

DOI: 10.26102/2310-6018/2024.45.2.009

The method of computer-aided design of the exoskeleton of the lower extremities using parametric design is intended for creating medical exoskeletons of the lower extremities according to the anthropometric parameters of the operator, which allows reducing the error in combining the axes of movement of the exoskeleton joints and the axes of movement of the operator’s joints. The method is based on rebuilding a reference model of the exoskeleton of the lower extremities according to the anthropometric data of the operator and includes the following design procedures: the procedure for taking measurements from the operator, taking the image obtained as a result of 3D scanning, filling out the application form that takes into account operational requirements, outputting the rebuilt exoskeleton model and accompanying documentation. To determine the elemental base of the exoskeleton, a database of electrical and radio components selected for operational requirements is used. To construct a frame corresponding to anthropometric data, a previously created reference model of the lower extremity exoskeleton is used. To test the model, the method also includes a virtual simulation of work by superimposing a rebuilt exoskeleton model on a 3D model of the operator obtained as a result of 3D scanning, followed by checking the animation of movements and the combination of model collisions. To test the effectiveness, we tested the construction of exoskeletons for the anthropometric data of the user using manual and automatic methods.

Keywords: design, CAD, automation, exoskeletons, anthropometric parameters, 3D model

Process control and development of a decision support system for classifying information signals based on Markov models

2024. T.12. № 2. id 1543

Osamah A.R. Kalinin M.Y. Mutin D.I.

DOI: 10.26102/2310-6018/2024.45.2.001

The necessity of controlling the process of classifying information signals based on simple and two-connected Markov models is substantiated. The possibility of combining previously obtained models and a classification algorithm into a decision-making system in order to classify information signals (random processes) is shown according to the criterion of maximizing a posteriori probability. The article proposes a block diagram of the decision-making system, describes the developed software components that consistently implement both auxiliary and basic procedures that allow implementing previously synthesized Markov models and methods for evaluating their parameters, as well as a classification algorithm. The description of the possibility of learning the classification algorithm, both "with a teacher" and in the "self-learning" mode, is given, the volumes of samples of the observations provided by the studied signals for the formation of databases of Markov signal models, Markov models of signal classes are determined. The results of statistical simulation modeling of the dependence of the error probability on the size of the training sample are presented. Block diagrams of some software components of the decision support system are proposed. The results of the implementation of previously developed models, methods and algorithms in the form of software tools are considered, and the functionality of using these tools as part of a decision support system is shown. The results of calculations are presented, showing the adequacy of the solutions obtained and the functionality of the developed software tools. Conclusions are drawn about the possibility of using a decision support system in various subject areas, including when classifying the conditions of the patient's cardiovascular system according to the observed rhythmograms.

Keywords: process control, markov model, classification, a posteriori probability, decision support system, algorithm training

Analysis of adequacy of mathematical models of parameters of partially coherent signals in radio-technical systems

2024. T.12. № 2. id 1541

Glushankov E.I. Kondrshov Z. Sudenkova A. Rylov E.

DOI: 10.26102/2310-6018/2024.45.2.002

The article discusses the analysis of the adequacy of Markov models of parameters of partially coherent signals in radio systems based on stochastic differential equations, carried out in the MATLAB software environment. The results of modeling one-dimensional non-Gaussian and Gaussian continuous, discrete-continuous and mixed random processes are presented. The method of functional (quasi-Gaussian) approximation represents the multidimensional probability distribution density through one-dimensional component densities and elements of the correlation matrix of a vector random process. For the multidimensional probability distribution densities obtained as a result of this representation and the multidimensional stochastic differential equations synthesized on their basis, the modeling of vector random processes describing the parameters of partially coherent signals in continuous communication channels is considered. The compliance of the obtained models with theoretical distributions is assessed using the Kolmogorov-Smirnov goodness-of-fit criterion. The ranges of changes in the parameters included in the SDE at which the model can be considered consistent, as well as the influence of the parameters on the shape of the distributions under consideration, are studied. Based on the results obtained, it is possible to estimate the ranges of changes in the parameters of the models that determine the form of stochastic differential equations, under which the requirements for the adequacy of the obtained models of partially coherent in the spatial and frequency sense of signals in radio systems are met.

Keywords: partially coherent signals, stochastic differential equations, kolmogorov-Smirnov test, rayleigh and Gauss distribution models, functional approximation, white noise, poisson noise

Development of an algorithm for solving the problem of distributing training time in training areas

2024. T.12. № 2. id 1540

Reznikov D.A.

DOI: 10.26102/2310-6018/2024.45.2.008

During their service in the penal system, employees continuously improve their knowledge, skills, and abilities through official training. This article discusses the problem of allocating training time to different areas in order to maximize the value of minimal average grades in those areas. A solution algorithm has been developed. The first step involves determining the maximum possible increase in the minimal average score for one area as well as the amount of time required for this increase. If the resultant score value is lower than the average score in other areas, the second step identifies the maximum possible increases for multiple areas and the corresponding amount of time needed. The article also determines the type of relationship between the increase in average grades for training areas and the time spent on training through the approximation of statistical data. This allows for the analytical solution of the problem. The analysis of the potential use of power and exponential functions for approximation, which allows for the approximate solution of a problem through numerical methods, is also conducted. The resulting values of the coefficient of determination confirm the high accuracy of the approximation. Graphs of the dependency are presented. Two examples of analytical solutions to the problem are provided, illustrating the use of the proposed method. In the first example, all employees have the same initial average training grades in all areas, and in the second example, average grades differ.

Keywords: average grade, average grade increment, learning time, learning curve, approximation, least squares method

A symbolic method for solving the initial boundary value problem for an inhomogeneous continuum transfer equation on a graph

2024. T.12. № 2. id 1539

Rybakov M.A.

DOI: 10.26102/2310-6018/2024.45.2.003

The relevance of the study is due to the need to obtain analytical expressions of approximate solutions to complex technical problems, the mathematical description of which leads to boundary value problems for systems of differential equations in network-like domains and, in particular, on graphs. The article presents the formulation of an initial boundary value problem for an inhomogeneous continuum transfer equation in an n-dimensional network-like region. In the case of n=1, a symbolic method for solving the initial boundary value problem under consideration on a tree graph is proposed. The algorithm is based on the approximation of the partial derivative with respect to a time variable by a difference ratio (a two-layer approximation scheme is used) and the subsequent application of the Laplace transform to the resulting differential-difference system. A block diagram of the algorithm is presented, and a description of the structure of the software package based on the developed algorithm is given. The software package is developed in the Java programming language. To enter the initial data of the initial boundary value problem and output the solution, the web interface of the software package based on the Spring framework is used. To illustrate the operation of the software package, an example of solving an initial boundary value problem with a step-by-step demonstration of the calculation results is considered. The materials of the article are of practical value for specialists in the field of analysis of applied problems of network hydrodynamics, thermal engineering, as well as analysis of diffusion processes in biophysics.

Keywords: symbolic method, differential-difference system, initial boundary value problem, continuum transfer equation, graph-tree

Optimization of structural and component design decisions in CAD of cyberphysical systems

2024. T.12. № 2. id 1538

Lvovich I.Y. Preobrazhenskiy A.P. Lvovich Y.E.

DOI: 10.26102/2310-6018/2024.45.2.022

The article presents the results of a study involving the formation of an optimization model and an interactive procedure for making structural and component decisions based on the principles of building an integrated CAD of cyberphysical systems (CFS). A description is given of the five main levels within which the CFS design process is implemented. Some approaches that were used by the authors during the design of the design elements of the CFS are considered. The description of how the optimization model of structural and component synthesis is formed is given. The main components of such an optimization model are given. The structural elements of the CFS are described on the basis of a set of formed sets. Three groups of indicators in the model are identified. The first group includes reliability and cost, which are calculated for the entire CFS as a whole. The second group includes the indicators calculated for some digital threads. The third group of indicators is related to the principle of covering the entire life cycle of the CFS from project to operation. An interactive procedure for making a structural and component design decision is presented. The generation of solution options is carried out in an automatic randomized search mode by replacing Boolean variables with random ones.

Keywords: cyberphysical system, CAD, structural and component design, optimization, expert assessment

Model for assessing energy and environmental development and security in the context of the transition to sustainable development of developing economies on the example of the BRICS countries

2024. T.12. № 2. id 1537

Shamaeva E.F.

DOI: 10.26102/2310-6018/2024.45.2.007

The connection between the concepts of “security” and “development” is inextricable, since security is a process, not a state. The preservation of the regional socio-economic system as a goal of ensuring security is achievable if the process of maintaining development proceeds in a chronological manner – both today and in the long term. The paper outlines the theoretical and methodological foundations of the energy flow concept for regional socio-economic systems. Based on this concept, the possibility of applying a comprehensive model of assessing energy and environmental development and energy security in the context of the transition to sustainable development of developing economies is proposed and tested using the example of a group of BRICS member countries (with the exception of Ethiopia, Iran and the UAE). Technological generalized efficiency factor is introduced as a key indicator of energy security and development of the regional socio-economic system. A comparative assessment of the economies of the BRICS countries was carried out according to the following indicators: technological total capacity, economic total capacity, technological useful power, economic useful power, the ratio of technological efficiency to economic efficiency. As a result of the analysis, it was found that Egypt among the BRICS countries (with the exception of Ethiopia, Iran and the UAE) has the highest growth rate of technological useful capacity. Also, based on the results of the study, a ranking of the energy security of various countries was compiled.

Keywords: energy and environmental development, energy security, BRICS countries, technological efficiency, economic efficiency

Detecting machine-generated texts with adaptive quantile regression

2024. T.12. № 1. id 1536

Tyurin A.S. Saraev P.V.

DOI: 10.26102/2310-6018/2024.44.1.033

This paper considers the problem of detecting machine-generated texts using various regression model building tools – classical linear regression, logistic regression and quantile regression. Advances in machine learning are creating increasingly realistic texts, which opens the door to misuse. As text generation algorithms become more sophisticated, the complexity of the task of detecting such texts increases, which also requires more sophisticated mathematical modeling methods and more efficient numerical methods. The proposed adaptive quantile regression algorithm is a tool that allows building models with emphasis on different quantiles, which makes it particularly useful for detecting atypical values that may indicate the artificial nature of the texts. The paper also presents a detailed description of the initial open dataset for model training, which is a set of generated texts using the GhatGPT 3 model and random texts from various forums, and analyzes the computational experiments performed. The results show the high efficiency of the proposed method in this field of application.

Keywords: text classification, quantile regression, adaptive algorithm, gradient descent, mathematical modeling, numerical methods

The problem of compromising the image recognition system by purposefully falsifying the training set

2024. T.12. № 2. id 1535

Khmeleva A.A. Demina R.Y. Azhmukhamedov I.M.

DOI: 10.26102/2310-6018/2024.45.2.005

This work is devoted to the problem of the security of image recognition systems based on the use of neural networks. Such systems are used in various fields and it is extremely important to ensure their safety from attacks aimed at artificial intelligence methods. The convolutional neural network ResNet18, the ImageNet verification set for recognizing objects in an image and classifying it to a class, and adversarial attacks aimed at changing the image processed by this neural network are considered. Convolutional neural networks detect and segment the objects that are in the images. The attack was carried out at the detection stage in order not to recognize the presence of objects in the image, as well as at the segmentation stage, the modified image attributed the recognized object to another class. A series of experiments was implemented that showed how an adversarial attack changes different images. To do this, images with animals were taken and an adversarial attack was carried out on them, the analysis of their results allowed us to determine the number of iterations necessary to make a successful attack. The original images were also compared with their versions modified during the attack.

Keywords: neural networks, attacks on neural networks, adversarial attacks, resNet18, transformation matrix

Mathematical modeling of the electrical properties of temporal nanocomposites with a complex structure

2024. T.12. № 2. id 1534

Korchagin S.A.

DOI: 10.26102/2310-6018/2024.45.2.006

During the research, a new modeling method was developed that makes it possible to adapt the electromagnetic response of the environment of a spontaneously ordered nanocomposite in time, using the concept of a temporarily effective environment, which can be used to create new nanostructured materials with specified electrical properties. Using computer technology and mathematical methods, modeling of the dielectric constant of temporal nanocomposites with a complex structure was carried out. A mathematical model developed to describe the dielectric constant of temporal nanocomposites is presented. The model takes into account various factors, such as the geometric parameters of nanoparticles, their concentration, orientation and characteristics of the dielectric matrix. Using the proposed model, numerical experiments were carried out to evaluate the influence of structural features on the dielectric constant of temporal nanocomposites. The work studied the distribution of the electric field in the time domain for nanocomposites with complex configurations and having a dielectric constant that varies periodically with time. The study demonstrated the possibility of using the effective medium model in problems of designing temporal nanocomposites of complex configurations. The research results can be used in practice-oriented problems related to the design of metamaterials with specified electrical properties.

Keywords: mathematical modeling, software, materials made of nanocomposites, computational research, permittivity

Coordination of processes according to probabilistic quality criteria with design symmetrization

2024. T.12. № 1. id 1533

Kuleshov I.V. Akhmedyanova G.F. Akhmedyanova P.A.

DOI: 10.26102/2310-6018/2024.44.1.029

The paper examines the issue of coordinating two processes by directing them towards the design values of the flow realized by these processes. The production process is considered random (since it is associated with the actions of personnel) and, in the first Markov approximation, is described by the Fokker-Planck-Kolmogorov equation. A study of the problem of optimal control of process coordination using probabilistic quality criteria shows that if one thread follows the other according to a tracking scheme, and the other provides the necessary level of readiness for the meeting, both threads will complicate each other’s management. Therefore, design symmetrization has been introduced, in which both the output of one process and the input of the second tend to the value specified by the design. Analysis of the first approximation obtained by the small decision parameter method shows that even with optimal control, the magnitude of control actions increases in proportion to the design value of the probability density and control duration; the increase in control actions over time should occur according to the cube of the exponential, that is, very slowly at the beginning of control and very sharply at the end, a similar pattern of increase is demonstrated by the dependence of control actions on the magnitude of the flow intensity, but it is expressed through hyperbolic functions.

Keywords: optimal control, markov process, probabilistic quality criteria, design symmetrization, small parameter method

Inventory control processes re-engineering and digitalization of a telecom-outsourcing enterprise

2024. T.12. № 1. id 1531

Krotov G.V.

DOI: 10.26102/2310-6018/2024.44.1.026

It is well known that digitalization in the logistics field can significantly increase the awareness of all stakeholders about the presence, status and movements of inventories, help to reduce losses, damage and theft of equipment and materials, and reduce the burden on personnel responsible for inventory control. Nevertheless, the subject area of inventory accounting in telecom-outsourcing organizations is not a widely researched area. The managers solve the arising practical issues of inventory accounting and its optimization following the example of the enterprises in other industries. The purpose of this study is to systematize the directions and methods of optimization of inventory accounting in telecom-outsourcing organization with the help of modern information technologies. The paper examines the links between traditional approaches to inventory accounting, their re-engineering, coordination and digitalization. The methodological aspect of the study includes identification of practical problems in the field of inventory accounting, systematization of terms, search for solutions to similar problems in other industries, identification of problem-solving options and analysis of relevant modern technologies. The main result is a systematized overview of the problems under consideration and ways to solve them with the help of organizational measures and IT. This paper can be useful both for researchers in the field of logistics and optimization theory to choose directions for in-depth study of the mentioned problems, and for practicing managers searching an overview of approaches to inventory optimization.

Keywords: telecom outsourcing, inventory accounting, reengineering, digitalization of business processes, supply chain management

Numerical methods for solving mathematical models of the temperature distribution of strips and rolls during hot rolling with interval parameters

2024. T.12. № 1. id 1528

Dabas M.R. Saraev P.V.

DOI: 10.26102/2310-6018/2024.44.1.028

The article considers the problem of temperature distribution in the strip and working rolls during hot rolling under the conditions of uncertainty of input parameters. The zone of the deformation gap with the formation of a rolling scale strip on the surface is regarded, as a result of which a system of thermal conductivity equations with different initial and boundary conditions is solved in the area of the deformation gap being studied. Next, the zone of the interstand gap is considered, where the heat exchange of the strip with the environment occurs. In all zones, the input parameters are represented as interval numbers. The deformation gap and the interstand gap were discretized from a continuous region into a grid one, systems of linear algebraic equations with tridiagonal interval coefficient matrices were derived using finite difference approximation, and a counter-run method with interval coefficients was presented to solve the obtained systems. The article considers the calculation results for 7 stands running one after another and consisting of a deformation gap and an interstand gap for the case with real input parameters and for the case with interval input parameters, calculations were performed using the developed software for both cases.

Keywords: equation of thermal conductivity, two-sided Thomas algorithm, interval arithmetic, hot rolling, finite difference approximation

Motion control along a program trajectory using a neural network

2024. T.12. № 1. id 1527

Grinyak V.M. Shutov K.S. Artemiev A.V.

DOI: 10.26102/2310-6018/2024.44.1.024

The paper examines the creation of a hardware and software prototype of an unmanned vehicle and testing its hardware and software architecture in an attempt to create a universal standard solution for this type of device. The problem of controlling a drone is considered in such a way that it is possible to flexibly switch the sources of control commands and control algorithms. For this purpose, the subsystems for generating and executing control commands are proposed to be connected via a message queue. It is makes possible to combine autonomous and manual controlled modes of operation of the drone. A method for generating control commands when an object follows a program trajectory, based on a neural network, is proposed. The input data of the network are the coordinates of the program trajectory and the current state of the object, and the output data are control actions. The paper describes the hardware and software components of an automobile-type device, the architecture of its control system, the architecture of a neural network, and possible approaches to its training. The creation of a training set using both simulated and real traffic data is discussed, which allows the self-driving device to “learn” different driving styles. The results of experiments with various training samples are presented, which demonstrate the practical applicability of the proposed control method. Attention is paid to aspects of the neural network structure, including the choice of the number of layers and neurons. The possibility of using “intermediate” points of the program trajectory to improve the properties of the object’s movement is indicated. In general, it is concluded that the use of neural networks is promising in the control of drones, in cases where combining and flexible switching of control algorithms is required.

Keywords: unmanned vehicle, vehicle control, navigation, autonomous vehicle, neural network

Finite element modeling of a metal tubing hanger seal

2024. T.12. № 1. id 1525

Timofeev E.K. Godenko A.E. Lipatov E.Y.

DOI: 10.26102/2310-6018/2024.44.1.022

The process of underwater oil and gas production is accompanied by high values of well pressure, which can reach thousands of atmospheres, while the service life of this equipment, laid down in the technical specifications, can reach 20 years or more. To ensure the safety of the subsea production process throughout the life of the equipment, it is important to pay special attention to the tightness and strength characteristics of metal seals as part of the design. In this regard, this article is aimed at identifying the degree of influence of such a geometric parameter as the depth of the recess on the characteristics of the tightness and strength of metal seals. The finite element method was modelled, using the Ansys calculation complex, of the stress-strain state of the metal seal of a tubing hanger of a standard design during installation and under the influence of well and test pressure. Finite element modeling was carried out using elastoplastic models of material deformations. To analyze the performance of a metal seal design, criteria for assessing strength and tightness are given. During the modeling, parameters characterizing the tightness and strength of the structure were determined. In order to study the degree of influence of the recess depth of the metal seal on the characteristics of tightness and strength, modeling was performed with an increase in this parameter to 80 %. The results of calculations of tightness and strength parameters with different recess depths are presented. The materials of the article are of practical value for design engineers and scientists dealing with the problems of ensuring a hermetic underwater connection using metal seals.

Keywords: subsea production system, metal seal, stress-strain state, tubing hanger, subsea Christmas tree, contact pressure

Model of selective assembly of two elements with dependence of the output parameter as a quotient of the input parameters

2024. T.12. № 1. id 1523

Filipovich O.V.

DOI: 10.26102/2310-6018/2024.44.1.027

The technological process of single-parameter selective assembly of two elements with parameters that are random variables, the values of which are determined by the finishing operations of the manufacturing processes, is considered. It is considered that the dependence between input and output parameters is nonlinear (nonlinear input-output models) and is represented in the form of quotient, and the completing rule is elementary. For a dependence of this type, expressions linking the values of tolerances (including group tolerances), limit deviations and limit values of input and output parameters are given. A method is proposed that helps to calculate group tolerances to fulfil the requirements to the accuracy of the output parameter in the whole area of its permissible values, as well as to determine the boundaries of selective groups. It is based on an iterative procedure, with each iteration consisting of sequentially executed steps. The output data of the previous iteration are the initial data for the next one. As a criterion for the end of the procedure, a given level of accuracy in calculating the average group tolerances is taken. The analytical and probabilistic model is developed, which takes into account the calculated boundaries of selective groups and helps to determine the most important indicators of selective assembly, such as the probability of formation of assembly sets, probabilities of formation of incomplete elements. An example of modelling is given, in which process indicators are determined using the developed method and model with given initial data. Prospects for further research are outlined.

Keywords: selective assembly, mathematical model, nonlinear dependence, quotient, iterative method

Triggers of motor activity measurable by near-infrared functional spectroscopy (fNIRS): a review

2024. T.12. № 2. id 1522

Samandari A.M. Afonin A.N.

DOI: 10.26102/2310-6018/2024.45.2.004

Scientific studies have differed on the interpretation of activity in the primary motor cortex of the brain. Various studies have found that the primary motor cortex is activated only during physical motor tasks. Whereas other studies have appeared that a similar measurable activity can be observed and recorded when arousing or stimulating the motor cortex when performing a mental representation of movement. Consequently, our purpose of this review was to compare the triggers of motor cortex activation during the physical execution and mental representation of the movement by recording the brain signals resulting from the stimulation by using the technique of near-infrared functional spectroscopy based on the neural interface (brain-computer interface). This research reveals differences and comparisons based on various approaches to analyze and systematically realize target triggers of motor cortex activation during training at neural interface (fNIRS). Based on the above, this review concludes by emphasising the fact that triggers of cortical activation in general and under different names cause activity that can be recorded by measuring the various changes that occur in hamoglobin concentration, in other words, that both physical task performance and similar mental representations of movement cause perceptible activity in the motor cortex. This provides the rationale for prosthetic, rehabilitation and other applications. Furthermore, this encourages future research to identify positive triggers for cortical activation to study psychological states of cognitive function and certain pathological conditions, as well as neurophysiological studies.

Keywords: near-infrared functional spectroscopy, triggers, motor cortex, brain-computer interface, physical movement, mental representation of movement

Mathematical model of a universal control system for a walking robot based on reinforcement learning methods

2024. T.12. № 1. id 1520

Kashko V.V. Oleinikova S.A.

DOI: 10.26102/2310-6018/2024.44.1.025

Modern approaches to solving the problem of controlling walking robots with rotary links are disparate algorithms built either on a ready-made locomotor program with its further adaptation or on complex kinematic-dynamic models that require extensive knowledge about the dynamics of the system and the environment, which is often unfeasible in applied problems. Also, the approaches used are strictly related to the configuration of the walking robot, which makes it impossible to use the method in applications with a different configuration (a different number and type of limbs). This article proposes a universal approach to controlling the motion of walking robots based on reinforcement learning methodology. A mathematical model of a control system based on finite discrete Markov processes in the context of reinforcement learning methods is considered. The task is set to build a universal and adaptive control system capable of searching for the optimal strategy for implementing a locomotor program in a previously unknown environment through continuous interaction. The results distinguished by scientific novelty include a mathematical model of this system, which makes it possible to describe the process of its functioning using Markov chains. The difference from existing analogues is the unification of the description of the robot.

Keywords: control system, reinforcement learning, markov decision processes, neural networks, walking robot, artificial intelligence

The concept for designing a telecommunication subsystem of the traffic control system for passenger ships in Moscow

2024. T.12. № 1. id 1518

Shakhnov S.F. Smolentsev S.V. Butsanets A.A. Ivanova A.A.

DOI: 10.26102/2310-6018/2024.44.1.023

The increasing density of water transport traffic in Moscow requires regulating the movement of numerous tourist, pleasure and scheduled boats, as well as ensuring the necessary level of safety for passenger transportation. The government of Moscow is creating a system for organizing the movement of passenger ships (SOMPS), which is designed to solve these problems in the waters of the central pool of Moscow between locks No. 9 and No. 10. The SOMPS concept for Moscow based on the engineering-cybernetic approach is developed in the paper. The choice of a higher-level system (meta-system), the requirements of which the designed system must satisfy, is justified. A block diagram of the SOMPS, which includes five subsystems, is presented. The factors determining the properties of the designed system and the limitations affecting the functioning of the SOMPS are considered. The developed concept of the SOMPS makes it possible to isolate the optimal structure of the telecommunication subsystem, which provides the necessary channels of control, management and information exchange between the SOMPS elements and external systems, and to determine its tasks. The communication channels that are part of the telecommunication subsystem are described. External and internal factors that can affect the functioning of the designed SOMPS and its telecommunication subsystem are presented. The necessity of introducing a module for calculating the meeting point of vessels under bridges into the designed SOMPS is substantiated. Methods for transmitting alarm signals between the SOMPS and external systems are described. An example of the VHF repeaters placement along the passenger route No. 1 on the river bends is presented. A conclusion about the optimality of the telecommunication subsystem structure, which ensures the fulfillment of assigned tasks while minimizing the resources involved is made.

Keywords: telecommunication subsystem, system for organizing the movement of passenger ships, moscow water area, engineering-cybernetic approach, communication channel, traffic management center of Moscow Government, AIS, automated operator workstation

The use of optimization modeling in the management of the iterative process in team-oriented organizational system of the IT industry

2024. T.12. № 1. id 1517

Korchagin S.G.

DOI: 10.26102/2310-6018/2024.44.1.020

The article discusses the process of working on a project in a team-oriented IT system using optimization modeling of the iterative process of purposeful team activity based on management principles in an Agile-oriented organizational system. For such a system, the general principles of flexible development methodologies aimed at accelerating the creation of projects by dividing the final requirements into smaller parts in order to take into account feedback from stakeholders at each stage of work are transformed into problem-oriented ones, which allows us to highlight the management features from the point of view used to consider the process of working on the project. It is shown that these principles are initially implemented at the level of the management center, in particular, the project manager should be well-acquainted with them, then at the team level and only after that the developed optimization programs should be implemented. The results of their application are shown in the description of each management feature. For an objective assessment of the effectiveness of the developed software tools, a comparison of the results of work on similar projects is given. In one, only the principles of flexible project management methodologies were applied; in the other, developed software tools were additionally employed to manage the iterative process of goal achievement in a team-oriented organizational system.

Keywords: agile-oriented organizational system, team activity, multi-alternative optimization, expert assessment, management decision-making

Adaptive quantile regression

2024. T.12. № 1. id 1514

Tyurin A.S.

DOI: 10.26102/2310-6018/2024.44.1.016

The relevance of the research is due to the growing need for fast and accurate tools for building mathematical models. This paper discusses approaches to building adaptive quantile regression because selecting the optimal quantile during the training process can save a large amount of researcher's time. The correct choice of quantile can significantly improve the performance of the model on test datasets and, as a consequence, obtain more reliable predictions when such a mathematical model is actually used. The developed approach is a combination of modified quantile regression and gradient descent, which improves the adaptation of the model to different data. A detailed description of the developed algorithm is given. The paper also presents a comparison of the performance accuracy of the proposed model with traditional quantile regression and gradient descent along with their combinations. It also analyzes the training time of the models, including the number of training epochs. Experiments show that adaptive quantile regression exhibits improved accuracy with reduced training time. The results emphasize the effectiveness of this method in data analysis and prediction, opening new perspectives for more efficient and faster machine learning models.

Keywords: quantile regression, adaptive algorithm, gradient descent, mathematical modeling, numerical methods