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Analysis of the Dynamics of Solutions for Hybrid DifferenceLotka–Volterra Systems 差分- otka - volterra混合系统解的动力学分析
IF 0.58
Journal of Applied and Industrial Mathematics Pub Date : 2025-07-11 DOI: 10.1134/S199047892404015X
A. V. Platonov
{"title":"Analysis of the Dynamics of Solutions for Hybrid Difference\u0000Lotka–Volterra Systems","authors":"A. V. Platonov","doi":"10.1134/S199047892404015X","DOIUrl":"10.1134/S199047892404015X","url":null,"abstract":"<p> A difference system of the Lotka–Volterra type is considered. It is assumed that this\u0000system can operate both in some program and perturbed modes. The restrictions on the time of\u0000the system’s stay in these modes, providing the desired dynamical behavior, are investigated. In\u0000particular, the conditions of the ultimate boundedness of solutions and the permanence of the\u0000system are obtained. The direct Lyapunov method is used, and different Lyapunov functions are\u0000constructed in different parts of the state space. The sizes of the domain of permissible initial\u0000values of solutions and the domain of the ultimate bound of solutions corresponding to the\u0000required dynamics of the system are estimated. Constraints are set on the size of the digitization\u0000step of the system.\u0000</p>","PeriodicalId":607,"journal":{"name":"Journal of Applied and Industrial Mathematics","volume":"18 4","pages":"812 - 823"},"PeriodicalIF":0.58,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145143116","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
The Problem of One Machine with Equal Processing Time andPreemption 具有等处理时间和抢占的一机问题
IF 0.58
Journal of Applied and Industrial Mathematics Pub Date : 2024-12-01 DOI: 10.1134/S1990478924030098
K. A. Lyashkova, V. V. Servakh
{"title":"The Problem of One Machine with Equal Processing Time and\u0000Preemption","authors":"K. A. Lyashkova,&nbsp;V. V. Servakh","doi":"10.1134/S1990478924030098","DOIUrl":"10.1134/S1990478924030098","url":null,"abstract":"<p> We consider the problem of minimizing the weighted average execution time of\u0000equal-length jobs performance on one machine at the specified time of job arrival and the\u0000possibility of their interruption. The computational complexity of this problem is currently\u0000unknown. The article proposes an algorithm for preprocessing input data that allows reducing the\u0000problem to a narrower and more regular class of examples. The properties of optimal solutions are\u0000substantiated. Based on them, an algorithm for constructing a finite subset of solutions containing\u0000an optimal schedule has been developed. A parametric analysis of the schedules in this subset has\u0000been carried out that makes it possible to form a subclass of schedules that are optimal at some\u0000values of weights. A polynomially solvable case of the problem is isolated.\u0000</p>","PeriodicalId":607,"journal":{"name":"Journal of Applied and Industrial Mathematics","volume":"18 3","pages":"479 - 488"},"PeriodicalIF":0.58,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757937","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
Extrapolation of Tomographic Images Based on Dataof Multiple Pulsed Probing 基于多脉冲探测数据的层析成像外推
IF 0.58
Journal of Applied and Industrial Mathematics Pub Date : 2024-12-01 DOI: 10.1134/S1990478924030189
I. P. Yarovenko, P. A. Vornovskikh, I. V. Prokhorov
{"title":"Extrapolation of Tomographic Images Based on Data\u0000of Multiple Pulsed Probing","authors":"I. P. Yarovenko,&nbsp;P. A. Vornovskikh,&nbsp;I. V. Prokhorov","doi":"10.1134/S1990478924030189","DOIUrl":"10.1134/S1990478924030189","url":null,"abstract":"<p> This paper proposes a new approach to improving image quality in pulsed X-ray\u0000tomography. The method is based on establishing a functional dependence of the reconstructed\u0000images on the duration of the probing pulses and applying an extrapolation procedure. The\u0000numerical experiments demonstrated that the developed algorithm effectively suppresses the\u0000influence of scattered radiation and significantly increases image contrast. The proposed\u0000alternative approach allows substantially increasing the stability of the method even for media\u0000containing strong scattering inhomogeneities and with a significant level of noise in the projection\u0000data. In addition, the algorithm has greater stability to errors in the source data caused by an\u0000increase in the duration of the probing pulses. The numerical experiments confirmed the high\u0000efficiency of the extrapolation tomography algorithm for recovering the internal structure of the\u0000test object.\u0000</p>","PeriodicalId":607,"journal":{"name":"Journal of Applied and Industrial Mathematics","volume":"18 3","pages":"583 - 597"},"PeriodicalIF":0.58,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757895","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
Solvability of an Initial–Boundary Value Problemfor a Parabolic Equation with a Time-Nonlocal Termin Hölder spaces 具有时间非局部端点Hölder空间的抛物方程初边值问题的可解性
IF 0.58
Journal of Applied and Industrial Mathematics Pub Date : 2024-12-01 DOI: 10.1134/S1990478924030062
A. S. Fomenko
{"title":"Solvability of an Initial–Boundary Value Problem\u0000for a Parabolic Equation with a Time-Nonlocal Term\u0000in Hölder spaces","authors":"A. S. Fomenko","doi":"10.1134/S1990478924030062","DOIUrl":"10.1134/S1990478924030062","url":null,"abstract":"<p> We consider an initial–boundary value problem for a semilinear parabolic differential\u0000equation with a time-nonlocal term. This term contains the integral of the solution over the entire\u0000time interval on which the problem is considered. The solvability of the problem in\u0000Hölder classes is proved. The uniqueness of the solution is established under a constraint\u0000on the length of the time interval over which the solution is integrated in the nonlocal term.\u0000</p>","PeriodicalId":607,"journal":{"name":"Journal of Applied and Industrial Mathematics","volume":"18 3","pages":"441 - 447"},"PeriodicalIF":0.58,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757896","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 Maximum Number of Open Triangles in Graphs withFew Edges 关于少边图中开放三角形的最大数目
IF 0.58
Journal of Applied and Industrial Mathematics Pub Date : 2024-12-01 DOI: 10.1134/S1990478924030128
A. V. Pyatkin
{"title":"On the Maximum Number of Open Triangles in Graphs with\u0000Few Edges","authors":"A. V. Pyatkin","doi":"10.1134/S1990478924030128","DOIUrl":"10.1134/S1990478924030128","url":null,"abstract":"<p> A three-vertex subset is called an open triangle (OT) if it induces a subgraph with exactly\u0000two edges. The problem of finding graphs with maximum number of OTs is considered. It is\u0000proved that, in case of sufficiently many vertices, such a graph is unique in the class of graphs\u0000with constant difference between the numbers of edges and vertices.\u0000</p>","PeriodicalId":607,"journal":{"name":"Journal of Applied and Industrial Mathematics","volume":"18 3","pages":"516 - 520"},"PeriodicalIF":0.58,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757915","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
Convex Continuations of Some DiscreteFunctions 若干离散函数的凸延拓
IF 0.58
Journal of Applied and Industrial Mathematics Pub Date : 2024-12-01 DOI: 10.1134/S1990478924030049
D. N. Barotov
{"title":"Convex Continuations of Some Discrete\u0000Functions","authors":"D. N. Barotov","doi":"10.1134/S1990478924030049","DOIUrl":"10.1134/S1990478924030049","url":null,"abstract":"<p> We construct convex continuations of discrete functions defined on the vertices of the\u0000<span>( n )</span>-dimensional unit cube\u0000<span>( [0,1]^n )</span>, an arbitrary cube\u0000<span>( [a,b]^n )</span>, and a parallelepiped\u0000<span>( [c_1,d_1]times [c_2,d_2]times dots times [c_n,d_n] )</span>. In each of these cases, we constructively prove that, for any discrete function\u0000<span>( f )</span> defined on the vertices of\u0000<span>( mathbb {G} in {[0,1]^n, [a,b]^n, [c_1,d_1]times [c_2,d_2]times dots times [c_n,d_n]} )</span>, first, there exist infinitely many convex continuations to the set\u0000<span>( mathbb {G} )</span>, and second, there exists a unique function\u0000<span>( f_{DM}colon mathbb {G}to mathbb {R} )</span> that is the maximum of convex continuations of\u0000<span>( f )</span> to\u0000<span>( mathbb {G} )</span>. We also show that the function\u0000<span>( f_{DM} )</span> is continuous on\u0000<span>( mathbb {G} )</span>.\u0000</p>","PeriodicalId":607,"journal":{"name":"Journal of Applied and Industrial Mathematics","volume":"18 3","pages":"412 - 423"},"PeriodicalIF":0.58,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757894","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 Influence of Droplet Size on the Breakup InductionPeriod in the Flow behind a Shock Wave 激波后流动中液滴尺寸对破裂诱导期的影响
IF 0.58
Journal of Applied and Industrial Mathematics Pub Date : 2024-12-01 DOI: 10.1134/S1990478924030153
A. A. Shebeleva, A. V. Minakov, S. V. Poplavski, V. M. Boyko
{"title":"On the Influence of Droplet Size on the Breakup Induction\u0000Period in the Flow behind a Shock Wave","authors":"A. A. Shebeleva,&nbsp;A. V. Minakov,&nbsp;S. V. Poplavski,&nbsp;V. M. Boyko","doi":"10.1134/S1990478924030153","DOIUrl":"10.1134/S1990478924030153","url":null,"abstract":"<p> In this paper, we computationally study the influence of the initial diameter of a water\u0000droplet on the dynamics and breakup induction period in the flow behind a passing shock wave.\u0000For this purpose, a series of calculations were performed for a fixed Weber number\u0000<span>( mathrm {We} = 400 )</span> and a variable initial diameter\u0000<span>( d = 1.4, 2.8, 5.6 )</span> mm of the water droplet. The numerical technique is based on the VOF\u0000method, the LES model is used to take into account turbulence, and the technology of adapted\u0000dynamic grids is used to describe the behavior of the interfacial boundary at main turbulent\u0000scales; this has made it possible to resolve secondary water droplets up to 20\u0000<span>( mu )</span>m in size. The droplet shape, the flow structure near and in the droplet wake,\u0000and the nature of mass entrainment were investigated. As a result of the calculations, the\u0000dependences of the breakup time on the dimensionless droplet diameter were obtained, the\u0000breakup induction time was determined, and the time constant of droplet interaction with the flow\u0000was calculated to estimate the droplet breakup lag.\u0000</p>","PeriodicalId":607,"journal":{"name":"Journal of Applied and Industrial Mathematics","volume":"18 3","pages":"548 - 557"},"PeriodicalIF":0.58,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757938","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 Conditions for the Well-Posed Solvabilityof a Factorization Problem and a Classof Truncated Wiener–Hopf Equations 一类分解问题及截断Wiener-Hopf方程的适定可解性条件
IF 0.58
Journal of Applied and Industrial Mathematics Pub Date : 2024-12-01 DOI: 10.1134/S1990478924030177
A. F. Voronin
{"title":"On Conditions for the Well-Posed Solvability\u0000of a Factorization Problem and a Class\u0000of Truncated Wiener–Hopf Equations","authors":"A. F. Voronin","doi":"10.1134/S1990478924030177","DOIUrl":"10.1134/S1990478924030177","url":null,"abstract":"<p> This paper continues the study of the relationship between the convolution equation of the\u0000second kind on a finite interval\u0000<span>( (0, tau ) )</span> (which is also called the truncated Wiener–Hopf equation) and\u0000a factorization problem (which is also called a vector Riemann–Hilbert boundary value problem or\u0000a vector Riemann boundary value problem). The factorization problem is associated with a family\u0000of truncated Wiener–Hopf equations depending on the parameter\u0000<span>( tau in (0,infty ) )</span>. The well-posed solvability of this family of equations is shown depending on\u0000the existence of a canonical factorization of some matrix function. In addition, various possible\u0000applications of the factorization problem and truncated Wiener–Hopf equations are considered.\u0000</p>","PeriodicalId":607,"journal":{"name":"Journal of Applied and Industrial Mathematics","volume":"18 3","pages":"575 - 582"},"PeriodicalIF":0.58,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757914","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
Calculation of Thermal Currents in a Tungsten Plate and in aThin Layer of Tungsten Vapor during Pulse Heating with Allowance for Temperature- andPhase-Dependent Electrical Resistance and Thermo EMF 脉冲加热时钨板和钨蒸气薄层的热电流计算，考虑温度和相位相关电阻和热电动势
IF 0.58
Journal of Applied and Industrial Mathematics Pub Date : 2024-12-01 DOI: 10.1134/S1990478924030086
G. G. Lazareva, V. A. Popov
{"title":"Calculation of Thermal Currents in a Tungsten Plate and in a\u0000Thin Layer of Tungsten Vapor during Pulse Heating with Allowance for Temperature- and\u0000Phase-Dependent Electrical Resistance and Thermo EMF","authors":"G. G. Lazareva,&nbsp;V. A. Popov","doi":"10.1134/S1990478924030086","DOIUrl":"10.1134/S1990478924030086","url":null,"abstract":"<p> In this paper, we consider a model of current distribution in a tungsten specimen and the\u0000evaporated substance when the surface is heated by an electron beam. The model is based on\u0000solving the equations of electrodynamics and the two-phase Stefan problem for calculating the\u0000specimen area temperature in a cylindrical coordinate system. We use a model temperature\u0000distribution in a thin layer of evaporated tungsten that replicates the surface temperature.\u0000Thermal currents are obtained using approximate temperature dependences of the electrical\u0000resistance and thermo emf of tungsten and its vapor. The model parameters are taken from\u0000experiments at the Beam of Electrons for materials Test Applications (BETA) stand, created at\u0000the Budker Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of\u0000Sciences.\u0000</p>","PeriodicalId":607,"journal":{"name":"Journal of Applied and Industrial Mathematics","volume":"18 3","pages":"465 - 478"},"PeriodicalIF":0.58,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757920","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
A Computational Study of Cuttings Transportin a Horizontal Well with an Oil-Based Drilling Fluid Modified by Multiwalled CarbonNanotubes 多壁碳纳米管改性油基钻井液水平井岩屑运移的计算研究
IF 0.58
Journal of Applied and Industrial Mathematics Pub Date : 2024-12-01 DOI: 10.1134/S1990478924030190
V. A. Zhigarev, D. V. Guzei, E. I. Lysakova, V. Ya. Rudyak, A. V. Minakov
{"title":"A Computational Study of Cuttings Transport\u0000in a Horizontal Well with an Oil-Based Drilling Fluid Modified by Multiwalled Carbon\u0000Nanotubes","authors":"V. A. Zhigarev,&nbsp;D. V. Guzei,&nbsp;E. I. Lysakova,&nbsp;V. Ya. Rudyak,&nbsp;A. V. Minakov","doi":"10.1134/S1990478924030190","DOIUrl":"10.1134/S1990478924030190","url":null,"abstract":"<p> We have conducted a computational study of the effect of adding multiwalled carbon\u0000nanotubes (MWCNTs) to oil-based drilling fluids on the efficiency of cuttings removal from\u0000an annular channel simulating a horizontal section of a well. To simulate the process of sludge\u0000transport in an annular channel, a mathematical model based on the Eulerian approach of\u0000a granular medium for a turbulent flow regime has been developed. The rheology of the drilling\u0000fluid modified with MWCNTs was described by the Herschel–Bulkley model with experimentally\u0000determined rheological coefficients. The base oil-based drilling fluid was an inverse emulsion with\u0000a ratio of hydrocarbon and water phases equal to 65/35. The concentration of MWCNTs in\u0000solutions varied from 0.1 to 0.5 wt %. The size of the transported sludge particles varied\u0000from 2 to 7 mm. The flow structure of a two-phase flow in an annular channel for various\u0000concentrations of MWCNTs has been studied. The dependences of the sludge removal efficiency\u0000coefficient, the average slip speed of sludge particles, and pressure losses on the concentration of\u0000nanotubes are obtained. It has been established that the addition of nanotubes leads to a\u0000significant change in the flow pattern of the drilling fluid and, as a result, to a change in the\u0000modes of cuttings transport. Addition of 0.5 wt % of MWCNTs leads to an increase in the\u0000efficiency of well flushing by approximately 40%. Thus, based on the results of the computational\u0000study, it has been shown that the addition of multiwalled nanotubes to oil-based drilling fluids can\u0000lead to an increase in the efficiency of cuttings transport in horizontal wells.\u0000</p>","PeriodicalId":607,"journal":{"name":"Journal of Applied and Industrial Mathematics","volume":"18 3","pages":"598 - 611"},"PeriodicalIF":0.58,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757921","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
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