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  • Development of a mathematical model for testing the natural ventilation: a case study for the Yemeni residents

    The article gives an insight into the traditional passive cooling techniques utilized in Mediterranean and hot climate regions, showcasing the effectiveness of natural ventilation and central patios in improving indoor thermal comfort and reducing energy consumption. The integration of these traditional design elements with modern technologies is crucial for creating environmentally friendly and culturally significant architectural solutions for the future. The discussion then transitions to the importance of energy efficiency and environmental sustainability in modern building design, highlighting the use of Ansys Fluent software for modeling natural ventilation in a residential apartment in Yemen. The article emphasizes the need for engineering and architectural solutions to achieve high performance in energy efficiency and environmental safety in contemporary construction practices.

    Keywords: natural ventilation, Yemeni houses, Spalart-Allmaras model, civil engineering, Ansys Fluent

  • Modeling of the atmospheric boundary layer under various stratification conditions

    The purpose of this article is to analyze the atmospheric boundary layer (ABL) models used in computational fluid dynamics packages, which take into account various conditions of atmospheric stratification. The hypothesis of the study is that in this case, the boundary conditions and model parameters should ensure the a horizontally homogeneous flow in the empty computational domain. An overview of works devoted to this topic is given, as well as an example of calculation results obtained using one of the models. The review shows that the considered models used in computational fluid dynamics packages make it possible to include effects associated with atmospheric stratification and obtain horizontally homogeneous vertical profiles of ABL characteristics. It is also possible to identify issues raised by the authors of works in this area, such as modeling of a stable boundary layer, modeling cases of strong convection and stability.

    Keywords: atmospheric boundary layer, computational fluid dynamics, CFD modeling, vertical profiles of meteorological parameters, boundary conditions, atmospheric stratification, k-ε-model

  • Design of diffusion coatings on steel parts

    The article presents a model for the formation of a thermodiffusion layer on steels. Thermodiffusion coatings on 45 steel and HVG steel were obtained by a chemical-thermal method in a powder mixture. Studies of layered X-ray diffraction phase and microrentgenospectral analysis of the studied coatings have been carried out. on steel. The obtained results of X-ray diffraction and microrentgenospectral analysis of diffusion coatings confirm the correctness of the model of formation of the diffusion layer and the theoretical prerequisites outlined. The results of the study can be used in the preparation of mixtures for thermal diffusion saturation.

    Keywords: diffusion layer, diffusion chrome plating, diffusion coating

  • Determination of the permeability of a porous medium based on thrice periodic minimum Neovius surfaces

    This article presents the results of a study of the filtration flow in a porous material based on a thrice periodic minimum surface (TPMP) Neovius. The Brinkman model was used to determine the profile of the fluid flow velocity in the channel containing the TPMP insert. Based on computational experiments in ANSYS Fluent, the dependence of the permeability of the medium on its porosity is determined. The results of the study can be used to describe filtration processes in the oil and gas industry, hydrogeology and other fields related to filtration flows in rocks and other media.

    Keywords: permeability, filtration, porous medium, minimum surface, TPMP, ANSYS, Brinkman model, numerical modeling, boundary value problem, velocity profile

  • Low-Latency Wavelet Image Processing Using the Winograd Method with Convolution Step

    Wavelets are widely used in various fields of science and technology for processing 1D signals and multidimensional images. However, technical information processing devices are developing more slowly than the amount of digital data is growing. Computational latency is the most important characteristic of such devices. This paper proposes an implementation of the Winograd method with a convolution step 2 to reduce the latency of wavelet image processing. The proposed scheme for implementing calculations has reduced the asymptotic computational complexity of wavelet processing of 2D images to 53% compared to the direct implemettaion method. A theoretical assessment of the computing device characteristics showed a reduction in latency of up to 67%. A promising direction for further research is the hardware implementation of the proposed approach on modern microelectronic devices.

    Keywords: image processing, Winograd method, digital filtering, computational delay, wavelet transform, convolution with step

  • Modeling the behavior of cylindrical shell structures weakened by holes

    Modeling the behavior of cylindrical shell structures weakened by holes when applying a load evenly distributed over the surface, taking into account geometric nonlinearity in the finite element software package ANSYS Mechanical APDL 2022R. Models of cylindrical shell structures with various hole arrangements have been created, and an analysis of the behavior of structures with an increase in the magnitude of the acting external uniformly distributed load has been carried out. Material type: isotropic, steel. Load-deflection graphs are obtained. The values of the critical load at which the structure loses stability are found. The values of internal stresses arising in structures under the influence of a critical load are found. The values of the displacement of the nodes are found: central and quarter under the influence of a critical load.

    Keywords: Shell structures, stress-strain state, loss of stability, finite element method, deflection, supercritical behavior, geometric nonlinearity, step-by-step application of load, load–deflection dependence graph, isotropic material

  • Artificial intelligence and decision theory: current trends

    The activities of modern enterprises and organizations are becoming increasingly complex, which complicates decision-making tasks. In this regard, the issues related to the integration of innovative information technologies in the field of decision-making are being updated. One of these technologies is artificial intelligence, the main advantages of which are the ability to solve time-consuming tasks and perform analysis based on big data in real time. The purpose of the work is to analyze the methods of applying artificial intelligence technologies in the theory of decision-making. The paper considers the fundamental factors associated with the work of artificial intelligence, prospects and current trends in its development in solving decision-making problems. The scientific value of the article consists in an attempt to systematize knowledge regarding the use of intelligent technologies in decision-making theory. The materials of the article can be useful for modern software developers and the management of organizations.

    Keywords: artificial intelligence, algorithm, data analysis, decision-making, model, information technology

  • Using statistical edge-based modeling for motion detection in video

    In this article we present a novel algorithm for detecting moving objects using a stationary camera, which is based on statistical background modeling using edge segments. Traditional algorithms that rely on pixel intensity struggle in dynamic environments due to their inability to handle sudden changes in lighting conditions. These algorithms also tend to produce ghosting artifacts when a sudden change occurs in the scene. To address this issue, edge-based features that are robust to intensity variations and noise have been introduced. However, existing methods that rely on individual edge pixels suffer from scattered edge pixels and cannot effectively utilize shape information. Additionally, traditional segment-based methods struggle with variations in edge shape and may miss moving edges that are close to the background edges. In contrast to conventional approaches, our proposed method constructs the background model using regular training frames that may include moving objects. Furthermore, it avoids the generation of ghosting artifacts. Additionally, our method employs an automatic adaptive threshold for each background edge distribution to facilitate matching. This enhances the robustness of our approach to changes in illumination, camera movement, and background motion. Experimental results demonstrate that our method outperforms other techniques and efficiently detects moving edges despite the aforementioned challenges.

    Keywords: motion detection, edges, canny edge detector, gaussian of color, gaussian of gradient magnitude, normal distribution, adaptive thresholds, statistical map

  • The regression modieling the level of Ia river, Irkutsk State

    Analyses for the current publishes show that the problem of forecast water overflowing is actual and often causing a lot health threaten and other dangerouses. This article offers computing, analysis and development the regression model of the level of Ia river. The final model correspont the real data with proper level. The final calculation means that this model could be used for real forecast for defend the people from water's overflow.

    Keywords: model, simulation, river, water level, flood, emergency, forecast, statistics, monitoring, analysis, iya river, Irkutsk region

  • Algorithm for fragmentation and defragmentation of formal contexts

    A combinatorial problem - the problem of finding the set of all formal concepts of formal concepts is considered. The computational complexity of the problem is that the number of formal concepts depends exponentially on the size of the initial formal context. in the article to solve this problem, an algorithm for fragmentation and defragmentation of the formal context is given, based on the method of decomposing the formal context into fragments. The essence of the method is that the original formal context is divided into various fragments. The fragments have different sizes and a non-empty intersection. Each fragment is subsequently considered as a formal context and can again be subject to decomposition. As a result, a finite set of fragments is formed. Then formal concepts are found in each fragment and combined to form the desired set of all formal concepts of the formal context. The method is “non-distorting”: when dividing the context into fragments, new formal concepts are not formed and the sought-for concepts are not lost. The results of computational experiments are presented, showing the effectiveness of the developed algorithm.

    Keywords: formal concepts analisys, fragmentation algorithm, formal context, object-attribute table, combinatorial problem, the problem of finding the set of all formal concepts

  • Study of synchronization of almost-proportional and almost-periodic characteristics of time series

    In this study, an analysis of the time series was conducted using a class of shift functions for arithmetic and geometric progressions, along with their synchronization using logarithmic decrement. The closing prices of IBM company stocks were taken as the examined data for each trading day. The shift functions of geometric and arithmetic progressions revealed almost-proportions and almost-periods in the examined data. These detected patterns emphasize the importance of applying shift functions in the analysis of time series, allowing the extraction of internal patterns and periodic fluctuations that might go unnoticed with standard analysis methods. Computing the minima and corresponding values of the geometric progression enabled the identification of almost-periods in the data. These results not only confirmed visual observations but also enhanced our understanding of the internal patterns of the time series. The findings underscore the effectiveness of applying methods for analyzing time series based on almost-proportions and metric techniques. These approaches play a crucial role in uncovering hidden patterns and subtle periodicities in data, providing a fundamental foundation for more accurate analysis and successful forecasting.

    Keywords: nearly-proportionalities, synchronization of geometric progression, empirical data, geometric progression, shift functions

  • Investigation of geometric parameters in the approximation of curved surfaces

    The article considers the issue of studying the deviation of geometric parameters of a curved surface and a facet surface approximating it. The approximating surface was constructed by triangulation. To obtain adequate results when approximating a surface, it is necessary that the geometric parameters of the approximated surface differ minimally from the parameters of the faceted surface. One of the most important geometric parameters of a surface is its normal at a given point. The deviation of the normals of the given and approximating surfaces significantly affects the calculation error.

    Keywords: curved surface, faceted surface, normal to the surface, linear frame, tinted image, plane compartment

  • Automation of structural calculations of wooden light-framed buildings

    In connection with the revival of interest in wooden housing construction in Russia, the creation of specialized software systems for the calculation and design of buildings and structures made of wood is becoming relevant. One of the most popular systems in the world is light-frame housing construction. As one of the possible tools for automated design of light-frame wooden buildings, this article presents the FrameCAD program, developed at the Department of Metal, Wood and Plastic Structures of the Don State Technical University. Some of its capabilities are presented, allowing you to design wall fences of light-frame buildings, beamed wooden floors, perform calculations of individual frame elements taking into account the requirements of current regulatory documents and automatically generate albums of drawings of wooden structures in the domestic NormCAD program, as well as specifications for them factory made. FrameCAD has been tested in the design of a number of objects. The software product is developed by engineers who have many years of experience in the actual design and construction of light-frame buildings. It continues to be improved and supplemented, and in the future it may become a replacement for similar foreign complexes.

    Keywords: wooden structures, software package, wall panels, beam overlap, automated calculation

  • The mathematical modeling of heat transfer and hydrodynamics in plate-fin radiators with round fillets profile

    A numerical simulation was used to investigate heat transfer in plate-fin radiators with round fillet profiles of various depths, including 0.55 mm, 1.1 mm, and 1.5 mm. The issue of flowing air around a radiator with a mass flow rate of 10-3 to 4·10-3 кг/с and a temperature of 293 K was solved. The radiator was heated using a heater, whose temperature was set from 323 to 353 K. Changes in heat flow, pressure drop, and energy efficiency indicator were shown depending on the air mass flow, according to the calculation results. The research findings indicate that the radiator featuring round fillet profiles and a depth of 1.65 mm exhibits the highest heat flow and energy efficiency indicators, as well as the lowest pressure drop.

    Keywords: radiator, cooling system, numerical modeling, computational fluid dynamics, heat transfer, heat flow, pressure drop, energy efficiency, calculation, electronics

  • Obtaining an equivalent resistance modulus for a section of river with parallel arms

    The analysis of N.N. Pavlovsky's method for calculating the parameters of the riverbed in the branches is given. The reasons for the limitation of this method have been established. The Lagrange transform is used to find the extremum of the objective function for equations of uneven fluid motion, which makes obtaining an equivalent resistance modulus highly visual and easy to use. The results of the experiment are presented.

    Keywords: calculation method, multi-node sections of rivers, resistance modulus, N.N.Pavlovsky method

  • Modeling of the design of a synthesis gas burner

    The paper describes the process of modeling 3D structures of synthetic gas burners, with the analysis of the simulation results obtained for several types of models and the selection of optimal modes for them. The main use of the burner is planned for boiler equipment for household needs in private as well as apartment buildings, in the absence of central heating. In addition, the article provides a justification for the thermal parameters at the inlet and outlet of the burner.

    Keywords: synthesis gas, combustion, design parameters, combustion chamber, nozzle, modeling

  • Calculation of sediment formation in a porous heat exchanger and assessment of the influence of sediment on heat flow

    Using numerical simulation, particle deposition in a porous heat exchanger was studied; the mechanism of sediment formation was sinvestigated, and the influence of sediment on the heat flow was assessed. The influence of porous heat exchanger length, dust particle size, and air flow velocity on particle deposition efficiency, particle breakthrough, and heat flux value was studied. Research results have shown that with increasing length of the heat exchanger, the efficiency of dust particle deposition increases, which leads to the formation of sediment. In turn, the sediment reduces the value of the heat flow from the porous heat exchanger. Depending on the length of the heat exchanger and air velocity, the reduction in heat flow is 3.43-7.27%.

    Keywords: porous media, heat exchanger, particle deposition, deposition efficiency, particle breakthrough, sediment, heat flow, numerical modeling, computational fluid dynamics, calculation

  • Calculation of three-layer structures made of composite material

    The purpose of the work is to develop a methodology for calculating the stress-strain state of three-layer structures made of composite material under the action of dynamic loads in robotic systems: semi-natural simulation stands, intended mainly for testing the flight characteristics. The stand consists of movable channels that ensure movement of the tested product in three degrees of freedom. The algorithm for creating a three-layer stand made of composite material is as follows. We assign the characteristics of the filler to the model of stand, create surfaces on the model and assign to the created surfaces the characteristics of a multilayer composite material with the orientation of the base of the layers along the lines of the trajectories of maximum stresses. Calculations of a three-layer stand with eight-layer load-bearing layers, with different orientations of the layers, were carried out to determine the structure of a multilayer composite material of maximum strength and rigidity based on theories of the destruction of multilayer materials stating that the destruction of one layer leads to the destruction of the multilayer material as a whole. The stress-strain state of a three-layer of the stand for semi-natural modeling of maximum rigidity and strength was obtained. The developed methodology is applicable to a wide class of problems of calculating the robotic systems made of three-layer composite material.

    Keywords: material characteristics, multilayer composite material, modeling methods, three-layer structures, calculation, analysis

  • Design of a stand for testing the seismic resistance of butterfly check valves

    Tests to determine the seismic stability of elements of pipeline systems, in particular pipeline fittings, are included in the list of those necessary to confirm the operability of the element. In this study, a stand was developed for testing to determine the seismic stability of butterfly check valves, which are a type of pipeline fittings. A finite element analysis was carried out, data on maximum deformations, stresses and displacements of structural elements were obtained, and the response of the installation table to seismic impact was calculated. The resulting displacement values of the table structure do not exceed the limit values specified by the technical requirements and do not lead to distortion of the structure or destruction of joints, which makes it possible to move from design to manufacturing and commissioning of the stand.

    Keywords: vibration tests, seismic resistance test bench, pipeline, pipeline valves, swing back gate, mathematical modeling, finite element method, strength calculation, simulation modeling, stress-strain state

  • On the dynamics of a circular membrane with an elliptical hole

    The effectiveness of the modified Fourier method associated with the use of orthogonal splines is shown when solving the problem of dynamics of a circular membrane with an elliptical hole. A posteriori estimates of the accuracy of the obtained approximate solutions complement the previously proven theoretical convergence of the algorithm and characterize the high accuracy of solutions to the problem of membrane dynamics with a curved boundary. The differences between the approximate solutions of the problem presented in the form of finite series decrease with an increase in the number of grid nodes used in calculations.

    Keywords: Fourier method, orthogonal splines, finite series, dynamics of membrane, a posteriori estimation

  • Solving Poisson's equation using a physics-informed natural gradient descent neural network with Dirichlet distribution

    In this paper, a physics-informed neural network containing natural gradient descent is proposed to solve the boundary value problem of the Poisson equation. Machine learning methods used in solving partial differential equations are an alternative to the finite element method. Traditional numerical methods for solving differential equations are not capable of solving arbitrary problems of mathematical physics with equivalent efficiency, unlike machine learning methods. The loss function of the neural network is responsible for the accuracy of solving initial and boundary value problems of partial differential equations. The more efficiently the loss function is minimized, the more accurate the resulting solution is. The most traditional optimization algorithm is adaptive moment estimation, which is still used in deep learning today. However, this approach does not guarantee achieving a global minimum of the loss function. We propose to use natural gradient descent with the Dirichlet distribution which increase the accuracy of solving the Poisson equation.

    Keywords: natural gradient descent, Poisson equation, Fisher matrix, finite element method, neural networks

  • Mathematical modelling of the stress-strain state of the southern part of the Siberian craton

    The aim of this study is mathematical modelling of the southern part of the Siberian craton using the finite element method. The task of the study is to carry out mathematical modelling of the stress-strain state of the visco-elastic-plastic medium of the Yakutsk-Vilyui large eruptive province on the basis of the boundary value problem. Hypothesis of the study: the possibility of using the results of numerical study to determine the zones of mineral dislocations. In the southern part of the craton, on the territory of the Republic of Sakha-Yakutia, there are the richest oil and gas fields, the largest of which is the Ust-Vilyuyskoye field located in the southern part of the craton. Research method: numerical experiment carried out by the method of mathematical modelling. Results achieved: finite element studies were carried out, the possibility of using numerical methods was determined, the stress-strain state of the plate was analysed, and the locations of anomalies of dislocations of craton rocks were determined to identify potential oil and gas bearing fields.

    Keywords: craton, mathematical modeling, stress-strain state, geophysics, geotectonics, stretching, igneous province, material models, Hardening Soil model, finite element method, mineral dislocation

  • Application of the Hartmann formula for calibration of prism spectral devices in a wide range

    Prism spectral devices have a spectrum-variable dispersion and therefore a nonlinear relationship between the wavelength and the position of spectral lines on the focal surface of a spectral monochromator device, which makes it difficult to calibrate such devices in terms of wavelengths and dispersion.Most often, the well-known Hartmat formula is used for graduation. However, the accuracy of its calculation is satisfactory only in a limited spectral range, and therefore the calculation is carried out on overlapping areas no wider than 200 nm with averaging in overlapping zones. Averaging gives a calibration curve (and, accordingly, a dispersion curve) with gaps at the joints. In this paper, we consider the possibility of using a single calibration for the entire spectrum region, providing smooth, continuous calibration curves. The best result is obtained by using the Hartmann formula for the entire spectral range, after which a set of deviations of the calibration points is determined. This set is interpolated by a polynomial of an arbitrarily chosen order n using the least squares method.

    Keywords: monochromator, spectrum, calibration, dispersion, Hartmann formula, interpolation, polynomial

  • Application of ANI-2x force field for modeling polyphenylene sulfide using classic molecular dynamics

    This work examines the applicability of a specific force field model – ANI-2x – to the polymer polyphenylene sulfide. The order of the actions taken is given and, as a result, the radial distribution function of sulfur atoms in systems with different temperatures is compared. It was shown that qualitatively the ANI-2x field correctly describes the situation during the transition through the glass transition temperature.

    Keywords: poluphenylene sulfide, classic molecular dynamics, machine learning, force field, potential, polymer, computer simulation, model

  • Using segment tree in PostgreSQL

    The article considers an approach to solving the problem of optimizing the speed of aggregating queries to a continuous range of rows of a PostgreSQL database table. A program module based on PostgreSQL Extensions is created, which provides construction of a segment tree for a table and queries to it. Increased query speed by more than 80 times for a table of 100 million records compared to existing solutions.

    Keywords: PostgreSQL, segment tree, query, aggregation, optimization, PosgreSQL Extensions, asymptotics, index, build, get, insert