Software & Systems

Articles of journal № 2 at 2023 year.

Order result by: Public date | Title | Authors |

1. Absolute stability of explicit difference schemes for the heat equation under Fourier–Tikhonov regularization [№2 за 2023 год]
Author: Bakhmutsky, M.L.
Visitors: 1461
The paper considers the possibility of constructing a simple and absolutely stable explicit difference scheme for the heat equation. Due to the too rigid stability condition, the invention of the sweep method for solving SLAE with three diagonal matrices, and splitting schemes, absolutely stable implicit schemes forced out explicit schemes for the heat equation of programming practice. However, implicit schemes are poorly parallelized. Therefore, programs for solving problems of heat conduction, diffusion, underground hydrodynamics, etc. on huge spatial grids using multiprocessor computing systems require using explicit difference schemes. This is especially true for multiprocessor systems of teraflop and higher performance that combine hundreds of processors. In this case, explicit schemes must be absolutely stable or, in the extreme case, their stability condition must be no more stringent than the same for hyperbolic equations. The paper proposes modifications of explicit difference schemes that approximate a parabolic equation and have absolute countable stability. Countable stability of a solution obtained at each time step by the classical explicit scheme is achieved by the fast Fourier transform and the subsequent Fourier synthesis with Tikhonov regularization. When calculating the direct and inverse Fourier transforms, the author used the Cooley–Tukey algorithm of the fast Fourier transform. There are the results of comparing numerical calculations of model problems with analytical solutions. The absolute stability of the proposed explicit schemes for the heat equation allows their wide use for parallel computations.

2. Information and software support for the automated system of scientific research on the survivability of gas production facilities [№2 за 2023 год]
Author: Valeev, A.F.
Visitors: 1029
The article is devoted to the automation of information processes of scientific research on the survivability of gas production facilities under the conditions of well flooding. The author proposes the structure of an automated system for scientific research of the survivability of gas production facilities, which includes a mathematical apparatus for modeling reservoir-well objects, watering processes and survival aids – various technologies for combating watering. The existing application software on the market for performing hydrodynamic modeling or hydraulic calculations does not allow studying the survivability of gas production objects. Therefore, a newly developed information and software for an automated system of scientific research that will allow assessing the survivability of gas production facilities under conditions of flooding, as well as helping a specialist to make decisions to improve it using technologies to combat flooding in wells. The automated system components are based on system analysis, the theory of hydraulics and oil and gas mechanics, object-oriented programming methods, statistical analysis, graph theory, modeling theory, control theory, nodal analysis method, etc. As a result of predictive modeling, the coefficient of survivability of gas production facilities is calculated taking into account the properties of efficiency, resource intensity when using means of ensuring survivability. Based on the given criterion, the system software offers the best technology to combat the watering of a gas production facility.

3. T5 language models for text simplification [№2 за 2023 год]
Authors: Vasiliev, D.D., Pyataeva, A.V.
Visitors: 1655
The problem of text readability in natural Russian is relevant for people with various cognitive impairments and for people with poor language skills, such as labor migrants or children. Texts constantly surround us in real life, such as various instructions, directions, and recommendations. Increasing the availability of these texts for these categories of citizens is possible by using an automated text simplification algorithm. This article used deep neural architecture transformers as an automated simplification algorithm. The following language models were applied: ruT5-base-absum, ruT5-base-paraphraser, ruT5_base_sum_gazeta, ruT5-base. Experimental studies used two data sets: a data set from the Institute of Philology and Language Communication and data from the open Github repository. The following set of metrics was used to evaluate the models: BLEU, Flesh Readability Index, Automatic Readability Index, and Sentence Length Difference. Further, using a test data set, statistical indicators were extracted from the listed metrics, which became the basis for comparing algorithms with different training parameters. The authors carried out several experiments with these models that used different values of the learning rate parameter for each dataset, batch sizes, and the exclusion of an additional dataset from training. Despite the different metrics, the models outputs did not differ much from each other during manual comparison. The results of experimental studies show the need to increase the data set for model training, as well as the change in the parameters of model training, or the use other algorithms. This study is the first step towards creating a decision support system for automatic text simplification and requires further development.

4. An algorithm and software implementation of test object model synthesis based on the solution of the nonparametric identification equation [№2 за 2023 год]
Authors: Gusenitsa, Ya.N., Mingachev, E.R., Iskhakov, N.U., Kolokolov, M.I.
Visitors: 1087
The paper considers the development of the theory of testing in general and the experimental-theoretical method in particular. In the aspect of this issue, the authors have developed an algorithm for synthesizing a model of a test object based on solving the equation of nonparametric identification of a dynamic system using hyperdelta approximation and the Laplace transform. Unlike the existing ones, the algorithm is applicable to input and output signals of arbitrary shape and physical quantities. In addition, it does not require large computing resources. Taking into account these features, the algorithm enables formalizing a multidimensional relationship between factors and performance characteristics of the test object through repeated use for different input and output signals. The authors have implemented a mathematical library for identifying a test object model and an application with a graphical user interface for automating calculations using the C++ and Python programming languages. The presented software solution is made similar to classical machine learning models. To substantiate the possibility of using the developed algorithm, the authors carried out a computational experiment that involved various types of input and output signals (periodic, non-periodic and random) with different hyperdelta approximation accuracy. Based on the results of the computational experiment, the authors have made recommendations on using the algorithm. In particular, they recommended to increase the number of initial moments of the hyperdelta approximation at high amplitudes of the output signal.

5. Optimal control of non-linear systems via quadratic criteria with bounded controls [№2 за 2023 год]
Authors: Emelyanova, I.I., Pchelintsev, A.N.
Visitors: 1313
The paper suggests a method of developing an optimal control of a single class of nonlinear systems via a quadratic criterion with a bounded type of inequality for the controls. This method is a further derivation from the method of successive approximations suggested in the earlier works of the group of authors, to which the authors of the current paper belong. By modifying the given method, the researchers have managed to state the existence of an optimal control of the problem in question and to synthesize the actual optimal control. The crucial issue of optimal control development is the problem of convergence of the method of successive approximations. Besides, the suggested scheme leads to a computational procedure that implies constructing a solution for a two-point boundary value problem. As known, it causes certain computational difficulties. In order to avoid those difficulties, the paper includes a modified scheme that converges and provides control which is close to an optimal one. It is demonstrated that the developed scheme reduces the initial problem to a sequence of Cauchy problems that can be easily solved using the simplest methods of numerical analysis. To illustrate the suggested method, the paper shows the results of a computational experiment on developing optimal control for a controlled system described with Van der Pol equation. In this case, it turned out that it is the modified scheme that gives the optimal control.

6. Aggregation and analysis of information from logistics companies to build a complex cargo transportation route [№2 за 2023 год]
Authors: Esin, M.S., Korepanova, A.A., Sabrekov, A.A.
Visitors: 957
The work is devoted to optimizing the construction of transportation routes in the field of cargo logistics. There are cases when cargo transportation between two cities by one transport company is more expensive than transportation by different companies with cargo transshipment at intermediate points. Information about such complex routes is of interest to both transport companies, which can find ways to reduce the cost of routes, and ordinary users looking for options for cheaper cargo delivery. The subject of the study is the automation of building the most profitable complex route for cargo transportation performed by several road and rail carriers and passing through intermediate points for transshipment (transfer of cargo). A distinctive feature of the research method used in this work is that it is based on the analysis of data from the calculator websites of carrier companies, which enable dynamical extraction of the transportation cost information is during a query process, as well as on heuristic approaches to building a complex route. The authors formulated the criteria for selecting potential transshipment points and their number. The proposed route cost estimation approach was tested on open data of 40 logistics companies, 9 cargo configurations and routes between 171 cities. As a result of the work, the authors proposed and tested a new heuristic algorithm for constructing a complex cargo transportation route and developed a software module. The test results have shown the effectiveness of the algorithm: using the proposed heuristics, in 10% of cases it is possible to build a complex route between cities, the cost of which might be significantly less than a simple one. The theoretical significance of the work lies in the development of a new algorithm for solving the problem of constructing a complex route for the transportation of goods, the practical significance lies in the implementation of a new module that will be implemented in the existing logistics service Cargotime.ru.

7. A comparative analysis of methods for constructing mathematical models of object functioning using machine learning [№2 за 2023 год]
Authors: Kovalnogov, V.N., Sherkunov, V.V., Hussein Mohamed Hussein, Klyachkin, V.N.
Visitors: 1467
The subject of the study is a technical object; its work is determined by many factors, its performance is charac-terized by some indicator. It is necessary to build a mathematical model that connects this indicator with the values of factors. As an example, the article examines the influence of various factors on the efficiency of burner devices (load, air consumption, methane and biogas, fuel and oxidizer compositions, and others). The efficiency (performance) of the burner device is assessed by the temperature of the flue gases. The problem is solved by machine learning methods, since classical regression analysis methods showed insufficient accuracy. The article explores the effectiveness of the following ap-proaches: the support vector method, random foresting and decision tree boosting. The authors used a localized version 13.3 of the Statistica system for numerical calculations. All three machine learning approaches discussed in the paper have shown a significant increase in the model accuracy on the test sample. The method of boosting decision trees has shown the best results in this example. The recommended model construction technology that provides the necessary forecasting accuracy is first reduced to testing the classical regression analysis (if the resulting model provides the necessary accuracy, then it is preferable from the point of view of its interpretability). If the accuracy is insufficient, the three considered methods of machine learning are used. It this case, it is important to select the parameters of each of the methods, which, on the one hand, would provide the necessary accuracy, on the other hand, would not lead to model retraining. The resulting model can be used to assess the influence of various factors on the efficiency of the technical facility, as well as to predict its functioning quality (in particular in the considered example, to predict the temperature of flue gases).

8. Developing a program self-assembly mechanism based on sockets [№2 за 2023 год]
Author: Kol’chugina, E.A.
Visitors: 1155
The paper focuses on methods and algorithms of spontaneous self-assembly and self-organization of software systems. Among the artificial chemistry models, there are some methods allowing program self-formation. But these methods are very specific and problematic for integration with conventional widespread and well-known imperative programming tools. Thus, it is necessary to offer other types of tools that enable dynamically establishing relations between programs or executing processes. The method previously proposed by the author is based on using Internet sockets connecting program units of different types. Some of these units are servers, some are clients, and some are of a hybrid client-server type. The units are generally considered as artificial atoms that react with each other and form complex substances (i.e. programs of different structures). This paper proposes the algorithms of such program units. Being implemented, these algorithms allow creating collectives of independent interacting program units capable to form different computing configurations. The designed algorithms are the basis for implementing the concept that allows spontaneous formation of the software in accordance with the specified rules under specified conditions. The experiments resulted in computational structures similar to real-world polymers and capable of pumping data through themselves. The obtained results are necessary for organizing a fully automated software development process based on the simulation of spontaneity. The program development process will require less human involvement and will therefore become more efficient and economically profitable.

9. Applying MATLAB in the design of digital filters for selecting Pc5 geomagnetic pulsations [№2 за 2023 год]
Author: Korobeynikov, A.G.
Visitors: 1345
The paper considers a design procedure of an optimal nonrecursive bandpass digital filter with a finite impulse response (FIR-filter) using the MATLAB Filter Design tool and the method of best uniform (Chebyshev) approximation. The filter helps solving the problem of extracting Pc5 geomagnetic pulsations from a data set of geomagnetic field measurements. This type of pulsations was chosen due to the availability of 1-second data in a widely spaced network of ground-based geomagnetic observatories with standardized ground-based geophysical equipment. After proper processing, these data can be used in a detailed analysis of: the disturbance properties in the Earth's magnetic field in the range of long-period pulsations; the nature of the interaction of waves and particles in the magnetosphere. The results of this analysis can be used, for example, in calculating a space weather forecast, which makes this work relevant. The problem of selecting Pc5 ripples is solved by passing the original data set through a band-pass FIR filter with the required characteristics depending on the range of the Pc5 ripple period – 150÷600 seconds. Hereof it follows the limits of the bandwidth equal to 1.7÷6.7 mHz. The choice of a non-recursive band-pass FIR filter is due to the possibility of providing a linear phase-frequency characteristic that excludes phase distortions at the output of the FIR filter; stability by definition of this type of filters. The first condition also ensures that there are no requirements for the phase response of the FIR filter. The operability of the obtained digital filter is demonstrated on the example of processing a real set of measurement data of the geomagnetic field state obtained from the Lycksele geomagnetic observatory (Sweden, Geological Survey of Sweden, international IAGA code LYC), which is a part of the INTERMAGNET international network. The necessary information about this observatory is available on the Internet: https://www.intermagnet.org. Bandpass FIR filter design and calculations were carried out in MATLAB R2022b.

10. A software package for personal identification by step cycle characteristics [№2 за 2023 год]
Authors: Leonov, S.V., Fomina, E.E.
Visitors: 1433
Recently, methods of identifying an individual by gait signs have gained particular interest due to active using of video surveillance systems. A significant advantage of this method is the fact that conducting examinations can be contactless and convenient from the point of view of collecting material. Nowadays, various methods of identifying an individual by gait characteristics are being actively developed. However, due to the large number of conditions affecting the movement manner, the task of identifying a person by gait still does not have a sufficiently accurate solution, so the problem of developing new methods is relevant. The article describes the method of identifying an individual in video shooting frames by such a kinematic indicator as a step cycle. The essence of the method consists in digitizing and quantifying the following step cycle parameters: the duration of double support and transfer periods, the step frequency and the pace of walking. The analysis of the listed indicators will make it possible to draw an expert conclusion about the similarity or difference of two individuals in the videos. To implement the proposed method, the authors have developed a software package for calculating step cycle characteristics. The software package includes the following modules: a module for entering primary information, a module for calculating the main step cycle characteristics, a module for generating a report. The main advantage of this technique and the software package is the ability to process video information from various angles, as well as in the case of fixing an object at a remote distance. The software package can be used in the development of a computer system for hybrid identity identification that includes modules for reading and analyzing biometric information, gait analysis modules for various shooting features.

| 1 | 2 | Next → ►