Discrete and Continuous Models and Applied Computational Science最新文献_第2页

Julia language features for processing statistical data Julia语言特性用于处理统计数据

Discrete and Continuous Models and Applied Computational Science Pub Date : 2023-03-30 DOI: 10.22363/2658-4670-2023-31-1-5-26

M. Gevorkyan, A. Korolkova, D. Kulyabov

引用次数: 0

Methods of extracting biomedical information from patents and scientific publications (on the example of chemical compounds) 从专利和科学出版物中提取生物医学信息的方法(以化合物为例)

Discrete and Continuous Models and Applied Computational Science Pub Date : 2023-03-30 DOI: 10.22363/2658-4670-2023-31-1-64-74

Nikolay A. Kolpakov, A. Molodchenkov, Anton V. Lukin

引用次数: 0

Studying the mechanism of electric explosion of metal conductors 金属导体电爆炸机理的研究

Discrete and Continuous Models and Applied Computational Science Pub Date : 2023-03-30 DOI: 10.22363/2658-4670-2023-31-1-75-86

N. Kravchenko, S. Kovtunov

引用次数: 0

Implementation of the Adams method for solving ordinary differential equations in the Sage computer algebra system 实现了在Sage计算机代数系统中求解常微分方程的Adams方法

Discrete and Continuous Models and Applied Computational Science Pub Date : 2023-01-01 DOI: 10.22363/2658-4670-2023-31-2-164-173

M. Malykh, Polina S. Chusovitina

{"title":"Implementation of the Adams method for solving ordinary differential equations in the Sage computer algebra system","authors":"M. Malykh, Polina S. Chusovitina","doi":"10.22363/2658-4670-2023-31-2-164-173","DOIUrl":"https://doi.org/10.22363/2658-4670-2023-31-2-164-173","url":null,"abstract":"This work is devoted to the implementation and testing of the Adams method for solving ordinary differential equations in the Sage computer algebra system. The Sage computer algebra system has, to some extent, trivial means for numerical integration of ordinary differential equations, but at the same time, it is worth noting that this environment is convenient and practical for conducting computer experiments related to symbolic numerical calculations in it. The article presents the FDM package developed on the basis of the RUDN, which contains the developments of recent years, performed by M. D. Malykh and his students, for numerical integration of differential equations. In this package, attention is paid to the visualization of the calculation results, including the construction of various kinds of auxiliary diagrams, such as Richardson diagrams, as well as graphs of dependence, for example, the value of a function or step from a moment in time. The implementation of the Adams method will be considered from this package. In this article, this implementation of the Adams method will be tested on various examples of input data, and the method will also be compared with the Jacobi system. Exact and approximate values will be found and compared, and an estimate for the error will be obtained.","PeriodicalId":34192,"journal":{"name":"Discrete and Continuous Models and Applied Computational Science","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68282925","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

Heterogeneous queueing system with Markov renewal arrivals and service times dependent on states of arrival process 马尔可夫更新到达和服务时间依赖于到达过程状态的异构排队系统

Discrete and Continuous Models and Applied Computational Science Pub Date : 2023-01-01 DOI: 10.22363/2658-4670-2023-31-2-105-119

E. Polin, S. Moiseeva, A. Moiseev

{"title":"Heterogeneous queueing system with Markov renewal arrivals and service times dependent on states of arrival process","authors":"E. Polin, S. Moiseeva, A. Moiseev","doi":"10.22363/2658-4670-2023-31-2-105-119","DOIUrl":"https://doi.org/10.22363/2658-4670-2023-31-2-105-119","url":null,"abstract":"In the proposed work, we consider a heterogeneous queueing system with a Markov renewal process and an unlimited number of servers. The service time for requests on the servers is a positive random variable with an exponential probability distribution. The service parameters depend on the state of the Markov chain nested over the renewal moments. It should be noted that these parameters do not change their values until the end of maintenance. Thus, the devices in the system under consideration are heterogeneous. The object of the study is a multidimensional random process - the number of servers of each type being served with different intensities in the stationary regime. The method of asymptotic analysis under the condition of equivalent growing of service times in the units of servers is applied for the study. The method of asymptotic analysis is implemented in the construction of a sequence of asymptotic of increasing order, in which the asymptotic of the first order determines the asymptotic mean value of the number of occupied servers. The second-order asymptotic allows one to construct a Gaussian approximation of the probability distribution of the number of occupied servers in the system. It is shown that this approximation coincides with the Gaussian distribution.","PeriodicalId":34192,"journal":{"name":"Discrete and Continuous Models and Applied Computational Science","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68283049","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

Quadratures with super power convergence 具有超幂收敛的正交

Discrete and Continuous Models and Applied Computational Science Pub Date : 2023-01-01 DOI: 10.22363/2658-4670-2023-31-2-128-138

A. Belov, Maxim A. Tintul, V. S. Khokhlachev

引用次数: 0

Convergence of the grid method for the Fredholm equation of the first kind with Tikhonov regularization 带Tikhonov正则化的第一类Fredholm方程网格法的收敛性

Discrete and Continuous Models and Applied Computational Science Pub Date : 2023-01-01 DOI: 10.22363/2658-4670-2023-31-2-120-127

A. Belov

引用次数: 0

Chebyshev collocation method for solving second order ODEs using integration matrices 利用积分矩阵求解二阶ode的Chebyshev配置法

Discrete and Continuous Models and Applied Computational Science Pub Date : 2023-01-01 DOI: 10.22363/2658-4670-2023-31-2-150-163

K. Lovetskiy, D. Kulyabov, L. Sevastianov, Stepan V. Sergeev

引用次数: 0

Buckling in inelastic regime of a uniform console with symmetrical cross section: computer modeling using Maple 18 具有对称截面的均匀控制台非弹性状态下的屈曲:使用Maple 18进行计算机建模

Discrete and Continuous Models and Applied Computational Science Pub Date : 2023-01-01 DOI: 10.22363/2658-4670-2023-31-2-174-188

V. Chistyakov, Sergey M. Soloviev

{"title":"Buckling in inelastic regime of a uniform console with symmetrical cross section: computer modeling using Maple 18","authors":"V. Chistyakov, Sergey M. Soloviev","doi":"10.22363/2658-4670-2023-31-2-174-188","DOIUrl":"https://doi.org/10.22363/2658-4670-2023-31-2-174-188","url":null,"abstract":"The method of numerical integration of Euler problem of buckling of a homogeneous console with symmetrical cross section in regime of plastic deformation using Maple18 is presented. The ordinary differential equation for a transversal coordinate (y) was deduced which takes into consideration higher geometrical momenta of cross section area. As an argument in the equation a dimensionless console slope (p=tg theta) is used which is linked in mutually unique manner with all other linear displacements. Real strain-stress diagram of metals (steel, titan) and PTFE polymers were modelled via the Maple nonlinear regression with cubic polynomial to provide a conditional yield point ((t),(sigma_f)). The console parameters (free length (l_0), (m), cross section area (S) and minimal gyration moment (J_x)) were chosen so that a critical buckling forces (F_text{cr}) corresponded to the stresses (sigma) close to the yield strength (sigma_f). To find the key dependence of the final slope (p_f) vs load (F) needed for the shape determination the equality for restored console length was applied. The dependences (p_f(F)) and shapes (y(z)), (z) being a longitudinal coordinate, were determined within these three approaches: plastic regime with cubic strain-stress diagram, tangent modulus (E_text{tang}) approximations and Hook’s law. It was found that critical buckling load (F_text{cr}) in plastic range nearly two times less of that for an ideal Hook’s law. A quasi-identity of calculated console shapes was found for the same final slope (p_f) within the three approaches especially for the metals.","PeriodicalId":34192,"journal":{"name":"Discrete and Continuous Models and Applied Computational Science","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68282991","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 a modification of the Hamming method for summing discrete Fourier series and its application to solve the problem of correction of thermographic images 对离散傅里叶级数求和的Hamming方法的改进及其在热成像图像校正中的应用

Discrete and Continuous Models and Applied Computational Science Pub Date : 2022-12-26 DOI: 10.22363/2658-4670-2022-30-4-342-356

E. Laneev, O. Baaj

{"title":"On a modification of the Hamming method for summing discrete Fourier series and its application to solve the problem of correction of thermographic images","authors":"E. Laneev, O. Baaj","doi":"10.22363/2658-4670-2022-30-4-342-356","DOIUrl":"https://doi.org/10.22363/2658-4670-2022-30-4-342-356","url":null,"abstract":"The paper considers mathematical methods of correction of thermographic images (thermograms) in the form of temperature distribution on the surface of the object under study, obtained using a thermal imager. The thermogram reproduces the image of the heat-generating structures located inside the object under study. This image is transmitted with distortions, since the sources are usually removed from its surface and the temperature distribution on the surface of the object transmits the image as blurred due to the processes of thermal conductivity and heat exchange. In this paper, the continuation of the temperature function as a harmonic function from the surface deep into the object under study in order to obtain a temperature distribution function near sources is considered as a correction principle. This distribution is considered as an adjusted thermogram. The continuation is carried out on the basis of solving the Cauchy problem for the Laplace equation - an ill-posed problem. The solution is constructed using the Tikhonov regularization method. The main part of the constructed approximate solution is presented as a Fourier series by the eigenfunctions of the Laplace operator. Discretization of the problem leads to discrete Fourier series. A modification of the Hamming method for summing Fourier series and calculating their coefficients is proposed.","PeriodicalId":34192,"journal":{"name":"Discrete and Continuous Models and Applied Computational Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46949584","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: 1