Pub Date : 2023-05-22DOI: 10.18500/1816-9791-2023-23-2-227-240
V. P. Radchenko, E. E. Derevyanka
{"title":"Kinetics of residual stresses in thin-walled cylindrical specimens after bilateral surface hardening under creep conditions with rigid constraints on angular and axial linear displacements","authors":"V. P. Radchenko, E. E. Derevyanka","doi":"10.18500/1816-9791-2023-23-2-227-240","DOIUrl":"https://doi.org/10.18500/1816-9791-2023-23-2-227-240","url":null,"abstract":"","PeriodicalId":42789,"journal":{"name":"Izvestiya of Saratov University Mathematics Mechanics Informatics","volume":"44 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82596916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-22DOI: 10.18500/1816-9791-2023-23-2-157-168
M. Komarov
{"title":"Rate of interpolation of analytic functions with regularly decreasing coefficients by simple partial fractions","authors":"M. Komarov","doi":"10.18500/1816-9791-2023-23-2-157-168","DOIUrl":"https://doi.org/10.18500/1816-9791-2023-23-2-157-168","url":null,"abstract":"","PeriodicalId":42789,"journal":{"name":"Izvestiya of Saratov University Mathematics Mechanics Informatics","volume":"38 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74727358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-22DOI: 10.18500/1816-9791-2023-23-2-253-263
S. F. Egorov, A. Y. Vdovin
. When developing electronic shooting simulators for manual automatic weapons that do not use ammunition, it is necessary to achieve the maximum realistic modeling of the bullet flight path for each shot taking into account a set of factors. Traditionally, a system of differential equations of outer ballistics is used in modeling the trajectory. The use of a constant value of the ballistic coefficient in such a mathematical model does not allow to achieve high accuracy of modeling the trajectory for such important for solving the “task of the meeting” parameters as complete flight time and excess of the trajectory for all targeted range of small arms. The initial values in the mathematical model based on the system of differential equations of the outer ballistic are the casting angle (depends on the settings of the sight), the initial speed and the ballistic coefficient of the bullet, and such parameters as the current excess, range, time, speed and direction are calculated. Estimates of the errors of the calculation of the coordinates of the ballistic trajectory at various approaches to the use of the value of the ballistic coefficient are given. It is concluded that at the moment when modeling the flight trajectory of the bullet, simplification based on the use of a constant value of the ballistic coefficient is quite justified but with the relevant requirements of the tactical and technical task the study of ways to increase the accuracy of the trajectory modeling will become relevant. One of these paths is using the value of the ballistic coefficient, depending on the casting angle proposed in this article.
{"title":"Investigation of the need to use the variable value of the ballistic coefficient when modeling the trajectory of the bullet in the shooter simulator","authors":"S. F. Egorov, A. Y. Vdovin","doi":"10.18500/1816-9791-2023-23-2-253-263","DOIUrl":"https://doi.org/10.18500/1816-9791-2023-23-2-253-263","url":null,"abstract":". When developing electronic shooting simulators for manual automatic weapons that do not use ammunition, it is necessary to achieve the maximum realistic modeling of the bullet flight path for each shot taking into account a set of factors. Traditionally, a system of differential equations of outer ballistics is used in modeling the trajectory. The use of a constant value of the ballistic coefficient in such a mathematical model does not allow to achieve high accuracy of modeling the trajectory for such important for solving the “task of the meeting” parameters as complete flight time and excess of the trajectory for all targeted range of small arms. The initial values in the mathematical model based on the system of differential equations of the outer ballistic are the casting angle (depends on the settings of the sight), the initial speed and the ballistic coefficient of the bullet, and such parameters as the current excess, range, time, speed and direction are calculated. Estimates of the errors of the calculation of the coordinates of the ballistic trajectory at various approaches to the use of the value of the ballistic coefficient are given. It is concluded that at the moment when modeling the flight trajectory of the bullet, simplification based on the use of a constant value of the ballistic coefficient is quite justified but with the relevant requirements of the tactical and technical task the study of ways to increase the accuracy of the trajectory modeling will become relevant. One of these paths is using the value of the ballistic coefficient, depending on the casting angle proposed in this article.","PeriodicalId":42789,"journal":{"name":"Izvestiya of Saratov University Mathematics Mechanics Informatics","volume":"69 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74118960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-22DOI: 10.18500/1816-9791-2023-23-2-142-156
G. Akishev
{"title":"On estimates of the order of the best M-term approximations of functions of several variables in the anisotropic Lorentz-Zygmund space","authors":"G. Akishev","doi":"10.18500/1816-9791-2023-23-2-142-156","DOIUrl":"https://doi.org/10.18500/1816-9791-2023-23-2-142-156","url":null,"abstract":"","PeriodicalId":42789,"journal":{"name":"Izvestiya of Saratov University Mathematics Mechanics Informatics","volume":"177 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77477286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-22DOI: 10.18500/1816-9791-2023-23-2-207-226
S. Lekomtsev, V. Matveenko, A. Senin
Аннотация. Оценена
注释。评估
{"title":"Passive damping of vibrations of a cylindrical shell interacting with a flowing fluid","authors":"S. Lekomtsev, V. Matveenko, A. Senin","doi":"10.18500/1816-9791-2023-23-2-207-226","DOIUrl":"https://doi.org/10.18500/1816-9791-2023-23-2-207-226","url":null,"abstract":"Аннотация. Оценена","PeriodicalId":42789,"journal":{"name":"Izvestiya of Saratov University Mathematics Mechanics Informatics","volume":"98 ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72504960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-22DOI: 10.18500/1816-9791-2023-23-2-195-206
S. Kashtanova, A. V. Rzhonsnitskiy
{"title":"Cylindrical shell with a circular hole under various loads: Comparison of analytical and numerical solutions","authors":"S. Kashtanova, A. V. Rzhonsnitskiy","doi":"10.18500/1816-9791-2023-23-2-195-206","DOIUrl":"https://doi.org/10.18500/1816-9791-2023-23-2-195-206","url":null,"abstract":"","PeriodicalId":42789,"journal":{"name":"Izvestiya of Saratov University Mathematics Mechanics Informatics","volume":"12 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74688575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-22DOI: 10.18500/1816-9791-2023-23-2-264-273
I. Lutoshkin, M. Rybina
. In the conditions of а mass disease, governing bodies of an economic system face a number of tasks related to the need to minimize its negative effects. This requires a tool that allows timely predicting the dynamics of the situation and determining what measures need to be taken. In this paper, a specialized mathematical model is proposed as such a tool, taking into account socio-biological and economic factors. The model is a dynamic optimal control problem with a delay in phase variables. The values of the model parameters were estimated using statistical data on the COVID-19 pandemic in the Russian Federation and the Ulyanovsk region. As target functionals, the following are considered: “social criterion” — a decrease in the number of cases; “economic criterion” — an increase in the relative profit of an economic system. To solve the problem, the authors apply a modification of the numerical parameterization method developed in their early studies. The article presents and analyzes the results of the numerical experiment aimed at studying the obtained optimal solutions. It is shown that: the optimal solution for social and economic criteria when changing budgets is stable; most of the parameters of the optimal solution are weakly elastic relative to the values of variables considered; the parameters of the optimal solution when using the economic criterion are more susceptible to change than when using the social criterion; the nature of the change in the parameters of the optimal solution for the Ulyanovsk region and for the Russian Federation is similar. Thus, the paper offers a tool for analyzing an economic problem in conditions of mass disease and confirms the applicability of the tool for finding optimal management strategies in various economic systems.
{"title":"Optimal solution in the model of control over an economic system in the condition of a mass disease","authors":"I. Lutoshkin, M. Rybina","doi":"10.18500/1816-9791-2023-23-2-264-273","DOIUrl":"https://doi.org/10.18500/1816-9791-2023-23-2-264-273","url":null,"abstract":". In the conditions of а mass disease, governing bodies of an economic system face a number of tasks related to the need to minimize its negative effects. This requires a tool that allows timely predicting the dynamics of the situation and determining what measures need to be taken. In this paper, a specialized mathematical model is proposed as such a tool, taking into account socio-biological and economic factors. The model is a dynamic optimal control problem with a delay in phase variables. The values of the model parameters were estimated using statistical data on the COVID-19 pandemic in the Russian Federation and the Ulyanovsk region. As target functionals, the following are considered: “social criterion” — a decrease in the number of cases; “economic criterion” — an increase in the relative profit of an economic system. To solve the problem, the authors apply a modification of the numerical parameterization method developed in their early studies. The article presents and analyzes the results of the numerical experiment aimed at studying the obtained optimal solutions. It is shown that: the optimal solution for social and economic criteria when changing budgets is stable; most of the parameters of the optimal solution are weakly elastic relative to the values of variables considered; the parameters of the optimal solution when using the economic criterion are more susceptible to change than when using the social criterion; the nature of the change in the parameters of the optimal solution for the Ulyanovsk region and for the Russian Federation is similar. Thus, the paper offers a tool for analyzing an economic problem in conditions of mass disease and confirms the applicability of the tool for finding optimal management strategies in various economic systems.","PeriodicalId":42789,"journal":{"name":"Izvestiya of Saratov University Mathematics Mechanics Informatics","volume":"43 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74213276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-22DOI: 10.18500/1816-9791-2023-23-2-169-182
E. H. Sadekova
{"title":"On the approximation of bounded functions by trigonometric polynomials in Hausdorff metric","authors":"E. H. Sadekova","doi":"10.18500/1816-9791-2023-23-2-169-182","DOIUrl":"https://doi.org/10.18500/1816-9791-2023-23-2-169-182","url":null,"abstract":"","PeriodicalId":42789,"journal":{"name":"Izvestiya of Saratov University Mathematics Mechanics Informatics","volume":"55 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84691495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-22DOI: 10.18500/1816-9791-2023-23-2-241-252
T. Z. Aralbaev, R. R. Galimov, M. A. Getman, O. V. Klindukh
{"title":"Hierarchical risk analysis of unmanned aerial vehicle threat models","authors":"T. Z. Aralbaev, R. R. Galimov, M. A. Getman, O. V. Klindukh","doi":"10.18500/1816-9791-2023-23-2-241-252","DOIUrl":"https://doi.org/10.18500/1816-9791-2023-23-2-241-252","url":null,"abstract":"","PeriodicalId":42789,"journal":{"name":"Izvestiya of Saratov University Mathematics Mechanics Informatics","volume":"48 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73248015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-21DOI: 10.18500/1816-9791-2023-23-1-83-94
E. Sadyrin
{"title":"Influence of a polymeric infiltrant on the density of enamel white spot lesions","authors":"E. Sadyrin","doi":"10.18500/1816-9791-2023-23-1-83-94","DOIUrl":"https://doi.org/10.18500/1816-9791-2023-23-1-83-94","url":null,"abstract":"","PeriodicalId":42789,"journal":{"name":"Izvestiya of Saratov University Mathematics Mechanics Informatics","volume":"121 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2023-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86860188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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