Izvestiya of Saratov University Mathematics Mechanics Informatics最新文献_第2页

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 考虑角和轴向线性位移约束的蠕变条件下，薄壁圆柱形试样双侧表面硬化后残余应力动力学

IF 0.2

Izvestiya of Saratov University Mathematics Mechanics Informatics Pub Date : 2023-05-22 DOI: 10.18500/1816-9791-2023-23-2-227-240

V. P. Radchenko, E. E. Derevyanka

引用次数: 0

Rate of interpolation of analytic functions with regularly decreasing coefficients by simple partial fractions 用简单部分分式插值系数正则递减解析函数的速率

IF 0.2

Izvestiya of Saratov University Mathematics Mechanics Informatics Pub Date : 2023-05-22 DOI: 10.18500/1816-9791-2023-23-2-157-168

M. Komarov

引用次数: 0

Investigation of the need to use the variable value of the ballistic coefficient when modeling the trajectory of the bullet in the shooter simulator 研究了在射击模拟器中对子弹的弹道进行建模时需要使用弹道系数的可变值

IF 0.2

Izvestiya of Saratov University Mathematics Mechanics Informatics Pub Date : 2023-05-22 DOI: 10.18500/1816-9791-2023-23-2-253-263

S. F. Egorov, A. Y. Vdovin

{"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}

引用次数: 0

Passive damping of vibrations of a cylindrical shell interacting with a flowing fluid 与流动流体相互作用的圆柱壳振动的被动阻尼

IF 0.2

Izvestiya of Saratov University Mathematics Mechanics Informatics Pub Date : 2023-05-22 DOI: 10.18500/1816-9791-2023-23-2-207-226

S. Lekomtsev, V. Matveenko, A. Senin

引用次数: 0

On estimates of the order of the best M-term approximations of functions of several variables in the anisotropic Lorentz-Zygmund space 各向异性Lorentz-Zygmund空间中若干变量函数的最佳m项逼近的阶估计

IF 0.2

Izvestiya of Saratov University Mathematics Mechanics Informatics Pub Date : 2023-05-22 DOI: 10.18500/1816-9791-2023-23-2-142-156

G. Akishev

引用次数: 0

Cylindrical shell with a circular hole under various loads: Comparison of analytical and numerical solutions 各种载荷下带圆孔圆柱壳:解析解与数值解的比较

IF 0.2

Izvestiya of Saratov University Mathematics Mechanics Informatics Pub Date : 2023-05-22 DOI: 10.18500/1816-9791-2023-23-2-195-206

S. Kashtanova, A. V. Rzhonsnitskiy

引用次数: 0

Optimal solution in the model of control over an economic system in the condition of a mass disease 群体性疾病条件下经济系统控制模型的最优解

IF 0.2

Izvestiya of Saratov University Mathematics Mechanics Informatics Pub Date : 2023-05-22 DOI: 10.18500/1816-9791-2023-23-2-264-273

I. Lutoshkin, M. Rybina

{"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}

引用次数: 0

On the approximation of bounded functions by trigonometric polynomials in Hausdorff metric 豪斯多夫度量中三角多项式对有界函数的逼近

IF 0.2

Izvestiya of Saratov University Mathematics Mechanics Informatics Pub Date : 2023-05-22 DOI: 10.18500/1816-9791-2023-23-2-169-182

E. H. Sadekova

引用次数: 0

Hierarchical risk analysis of unmanned aerial vehicle threat models 无人机威胁模型的层次风险分析

IF 0.2

Izvestiya of Saratov University Mathematics Mechanics Informatics Pub Date : 2023-05-22 DOI: 10.18500/1816-9791-2023-23-2-241-252

T. Z. Aralbaev, R. R. Galimov, M. A. Getman, O. V. Klindukh

引用次数: 0

Influence of a polymeric infiltrant on the density of enamel white spot lesions 聚合物浸润剂对牙釉质白斑病变密度的影响