bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computational algorithms for modeling systems with piecewise constant parameters
Authors: Skalko Yu I , Gridnev S Yu , Minaeva N V 
Published: May 2021

Abstract
Modeling systems with piecewise constant parameters imposes special requirements on the computational algorithms used. In places where the parameters are discontinuous, the model variables may experience discontinuities or smoothness disturbances. In this case, the conditions for matching the values of the variables on both sides of the discontinuity boundary, reflecting the physical conditions at this boundary, must be satisfied. The paper proposes computational algorithms for modeling these systems, based on the formulation of the initial initial-boundary value problem in the form of a system of partial differential equations for generalized functions. In this case, the initial conditions, conditions on the external and internal boundaries are included in these equations in a weak form. The latter circumstance makes it possible to avoid the need to subordinate the basis functions, according to which the desired solution is expanded, to the conditions on the outer and inner boundaries, which is an important circumstance, especially for problems with many spatial variables. The paper presents a solution to the generalized Riemann problem with conditions on the outer or inner boundary for a differential equation with second-order derivatives with respect to spatial variables. The solution to the Riemann problem is based on the formulation of the problem in the form of a partial differential equation for generalized functions and the construction of a fundamental solution to the problem operator. When constructing a computational algorithm, the solution of the generalized Riemann problem is used on the inner and outer boundaries. The proposed technique allows, by using high-degree polynomials as basis functions, to build computational algorithms of a high order of approximation.
The research of discrete and continuous models of impact devices by numerical methods
Authors: Slidenko A M , Slidenko V M 
Published: May 2021

Abstract
The article gives the research results of discrete and continuous models of an impact device by numerical methods. The discrete model makes it possible to evaluate the process of impulsive force of the striker with the tool taking into account the aftereffect of the resistance of the working medium. For the rod model, the initial boundary conditions are formulated, which take into account the impulsive force with the determination of the impact force by the Hertz method. The characteristics of nonlinear rigid and dissipative constraints depend on the difference in the displacements of the contact rod ends. The interaction of the tool with the working medium, in particular with the rock, is modeled by similar constraints. These processes are described by initial-boundary value problems with wave equations, which are different in initial and boundary conditions. Mixed difference schemes are used to solve problems. For the rods of variable cross-section, the voltage distribution along their length is determined. The results obtained are compared with the solutions by the Fourier method of model problems.
Stability of a three-dimensional plate made of a nonlinear viscoelastic material under superimposed finite deformations
Authors: Sumin A I , Boger A A , Sumin V A , Ryabov S V 
Published: May 2021

Abstract
In this paper, the stability of a three-dimensional plate made of a nonlinear viscoelastic material under finite perturbations is considered. A fairly broad computational experiment has been performed. The permissible boundaries of the region with respect to the final, initial perturbations are established for the given parameters of loading and structures. Finite sequences of bifurcation points are constructed, which confirm, in contrast to stability under small perturbations, the existence of a sequence of stable equilibrium states. New phenomena and characteristic effects are established.
Equivalent series theorem and obtaining some new summable numerical series using fast expansion polynomials
Authors: Chernyshov A D , Saiko D S , Kovaleva E N 
Published: May 2021

Abstract
A theorem on equivalent uniformly converging series is proved, which allows one to find a set of new spectra of summable series. The classification of number series into three classes is given. By expanding special polynomials in Fourier series in terms of various fundamental system of functions, it is possible to summarize a wide class of new numerical series that have a convenient classical form of the first class. These polynomials are borrowed from the fast expansions method of the authors of this article.
Risk-model for communication networks operation stability assessment
Authors: Ananev A V , Ivannikov K S 
Published: May 2021

Abstract
Assessment model of the communication networks operation stability based on the risk theory is developed. Unlike known in the offered model the operation stability level is characterized by scale coefficient of losses in risk expression. The scale coefficient is presented by ratio initial number bonds of fully connected graph to the bonds number after communication network nodes destroying. Such representation of communication networks operation stability allows first, to evaluate a level of influence of the heterogeneous deliberate and inadvertent destabilizing factors influencing a communication network. Second, to predict the communication networks operation stability depending on the nodes number for given defeat probability to a single node of the communication network.
On solving nonlinear differential-functional equations of mechanics and other applications
Authors: Byrdin A P , Sidorenko A A , Sokolova O A 
Published: May 2021

Abstract
The paper presents the results of a study aimed at creating a method for solving the Cauchy problem and the stationary problem for equations containing a linear differential operator with constant coefficients and a nonlinear analytical functional. The method of Volterra-Frechet series is used to obtain a stationary solution of a second-order differential equation with an analytical functional describing the oscillations of a nonlinear vibrator with hereditary behavior. The behavior of the solution and the dependence of energy losses on physical parameters are studied.
On elliptic problems in domains with low dimensional boundaries
Authors: Vasilyev V , Chernova O , Kovalyova L , Kutaiba Sh 
Published: May 2021

Abstract
We study a solvability for some concrete boundary value problems in domains with a low dimensional boundary. Such boundaries are considered as a limit situation of a volume problem for which one or more parameters of a domain tend to their endpoint values. The solvability conditions in Sobolev-Slobodetskii spaces are given using the wave factorization concept for an alliptic symbol..
To the question of the shape of the spatial curve of the fastest descent in the conditions of its rotation
Authors: Gladkov S O , Bogdanova S B 
Published: May 2021

Abstract
The non-linear system of dynamic equations of the movement of the ball, sliding down on rotating with frequency ω on one-dimensional gutter of arbitrary form, is obtained. From the minimum sliding time. defined by the form of this curve. Taking into account the forces of dry and viscous friction, the results of the analytical and numerical solution of the received system of equations are presented.
Solution of the Mainardi Signaling Problems with the Maxwell-Fejer impulse
Authors: Kostina T I , Silaeva M N , Mohamad Alkadi Hamsa , Pritsepov M U 
Published: May 2021

Abstract
In this paper, we study a problem describing the process of slow diffusion (subdiffusion), the mathematical model of which is a differential equation with a fractional derivative. The correct solvability of the Cauchy problem for the equation under consideration is established and the effect of slowing down the process depending on the order of the fractional derivative is shown.
The determination of redundant test patterns based on binary matrix symmetry properties
Authors: Petrukhnova G 
Published: May 2021

Abstract
The object of research are digital circuit control tests. The model of a digital circuit is of a grey-box type. Test patterns (impacts) are combinations of logical zeros and ones, applied to circuit inputs. A binary matrix is the response of a digital circuit to input impacts. The examined faults are of «bridging faults» and «stuck-at faults» types. We distinguish the structural units of a test, as well as transformations, maintaining its structure. The measure of binary matrix symmetry is defined. Based on the measure obtained, the criteria are introduced, which help to calculate the utility of another test impact upon a digital circuit. To investigate the criteria, both pseudo-random and deterministic test sequences have been used. Among others, we have observed such algorithmic sequences as a sliding-ONE test, a logarithmic test, a galloping test pattern and a checkerboard test. The proposed approach gives the possibility to identify and exclude the impacts, not carrying useful information, from a test of combinational circuit control. The developed criteria can also be applied to construct memory tests. The analysis of experimental data allows us to make a conclusion about the advisability of using the proposed mathematical apparatus in the theory and practice of digital device testing, as well as in processes of test development.
Economic-mathematical model of choice of heating system development option
Authors: Podvalny S L , Sotnikova O A , Zolotukhina Ya A , Prokshitst E E 
Published: May 2021

Abstract
The large number of the mathematical models describing the production and technological party of economy and intended for acceptance of effective solutions is so far developed. A considerable part of the constructed models to some extent is used in practice. However, despite the considerable achieved success remains many problems requiring the solution. So, many models carry out only preprocessing of information and its storage, but do not provide to the person, receiving the decision (PRD), means for the analysis of a situation and decision-making.
On the effect of transition from a model with concentrated parameters to a model with distributed parameters
Authors: Polovinkina M V 
Published: May 2021

Abstract
We note from a general point of view that adding diffusion terms to ordinary differential equations, for example, to logistic ones, can in some cases improve sufficient conditions for the stability of a stationary solution. We give examples of models in which the addition of diffusion terms to ordinary differential equations changes the stability conditions of a stationary solution.
Computer system of vibration analysis for evaluating extrusion equipment operability at productions of multi-assortment polymeric films
Authors: Fozilov M M , Chistyakova T B , Polosin A N 
Published: May 2021

Abstract
A computer system of vibration analysis has been developed to evaluate the operability of extrusion equipment. The computer system allows you to timely identify an abnormal situation associated with increased vibration of the extruder screw drive, determine its true cause and form recommendations to the production staff for troubleshooting. The computer system is configured for various types and geometric parameters of extruders used in the extrusion and extrusion-calender production of multi-assortment polymeric films. The algorithm for analyzing vibration signals includes the stages of obtaining the signal spectrum by applying a direct discrete Fourier transform and determining the faulty drive element as a result of analyzing the trend in the amplitudes of the signal harmonics at frequencies characteristic of various types of faulty elements. The computer system is integrated into a single quality control system for multi-assortment polymeric films. The results of testing according to the data of extruders of polymeric film production at plants in Russia and Germany confirmed the performance of the computer system. The use of a computer system allows you to save the life of the extrusion equipment, increase the time periods between its stops, and reduce the repair time.
The third boundary problem for the hyperbolic differential equation of the second order
Authors: Shevchenko G N , Borisenko A Yu 
Published: May 2021

Abstract
This article consider the solvability of the problem for the model linear homogeneous differential equation with partial derivatives of the second order of hyperbolic type on the plane in the square for the case of discontinuous conjugation conditions on the characteristics with the third series boundary conditions on the whole boundary of the region under consideration. Dalamber’s solution is used for this problem solving. The conditions for the single-valued solvability of the defined problem are clarified in this paper. As a result, an exact solution was obtained in an explicit form.
Structure synthesis of visualization system for the adaptive training complexes
Authors: Arkhipov A E , Karpuhskin S V , Kalach A V 
Published: May 2021

Abstract
Classification of the problems that can be solved as a result of development of adaptive training complexes, components and technologies in the system of visualization is proposed. A problem formulation of the structure synthesis for visualization system of adaptive training complex is offered implying the possibility of solution of maximum number of the training problems. A scheme of connections is developed between the problems and technologies, concretization of the visualization components that allow solving of a certain set of tasks.
Logic program invertibility in cryptography problems
Authors: Avkhimovich N 
Published: May 2021

Abstract
This work contains an analysis of problems those occur when the logic programs are used for cryptography problems. We explore the following problems: whether a logic program is invertible; whether one program is an inverse of the other. It was proved coNP-completeness for both problems. The size of logic programs also considered. We have found an instance of a program of linear length such that the length of the inverse program is exponential.
On second solutions of the sixth-order nonlinear mathematical model with measured derivatives
Authors: Borodina Elena , Shabrov Sergey , Golovaneva Faina , Kurkinskaya Eleanora 
Published: May 2021

Abstract
In the present paper the sixth-order nonlinear mathematical model with nonsmooth solutions is studied. We consider a case, when the problem is guaranteed to have one solution and investigate the question on the presence of one more. Using the pointwise approach of Yu. V. Pokorny, which has shown its effectiveness in analyzing models of the second and fourth orders, sufficient conditions of the existence of the second solution for the sixth-order model with derivatives with respect to measure are obtained.
Interpolation and masking effects of heteroassociative compressive transformations
Authors: Dryuchenko M , Sirota A 
Published: May 2021

Abstract
The article considers heteroassociative image transformations, which perform mutual mapping of two neighbouring or nested regions of arbitrary shape within rectangular fragments or blocks covering the image. Specifically, the study focuses on heteroassociative compressive transformations. In the article, we provide theoretical justification of various types of heteroassocia-tive transformations performed using neural network based converters and numerical methods. We also study interpolation and masking effects of the transformations, which can be observed during image processing. These effects are accounted for by the possibility to represent an image as a sum of the deterministic component of the output (which is either linear of nonlinear function of the in-put) and the additive stochastic component of the output responsible for the prediction error. The article analyses occurrence, genetic and heuristic algorithms used to optimise the input and output configuration of the fragments covering the image. The algorithms used allowed us to maximise (minimise) the deterministic and the stochastic component and thus regulate interpolation and masking effects of heteroassociative transformations.
Algorithmic undecidability of recognizing a non-Markovian group property
Authors: Durnev V G , Zetkina A I 
Published: May 2021

Abstract
We prove algorithmic undecidability of the following group property: “the positive theory of a group G coincides with the positive theory of a free non-Abelian group” or (which is equivalent) “the positive theory of a group G coincides with the positive theory of the class of all groups”. This group property is non-Markovian, therefore its algorithmic undecidability does not follow from the fundamental Adyan–Rabin theorem.
Movement of liquid droplets in a shear flow
Authors: Fedyushkin A I 
Published: May 2021

Abstract
The problem of the motion of a particle around a particle in a shear flow for the conditions of weightlessness and normal earth gravity is considered. The cases where the particle density is greater or less than the density of the main buffer moving fluid (oil particles in water and water particles in oil) are presented. On the basis of numerical modeling, the nature of the influences of gravitational, viscous, lifting and frontal forces on the trajectory of fluid particles in a shear fluid flow are shown. of diameter particles. For the considered liquid particles and stratification of the shear velocity field It is established that the minimum distance of approach of liquid droplets is equal approximately 0.07 of diameter particles.
Waveguide phase shifter based on controlled metamaterial
Authors: Ishchenko E A , Pasternak Yu G , Pendyurin V A , Rogozin E A , Fedorov S M 
Published: May 2021

Abstract
The paper present study of the opto-controlled metamaterial integrated into the waveguide design to control the phase of the flowing electromagnetic wave. A change in the metamaterial characteristics occurs when we switching nodes of a system consisting of thin metal conductors. In the course of the study a computer simulation of an electrodynamic system was carried out. It consists of a waveguide with dimensions of 26.4x10.62x200 mm and a metamaterial integrated into the structure, as a result of which, the flowing electromagnetic wave images, phase graphs S21 of the waveguide parameters were obtained.
Horn antenna with integrated metamaterial for beam steering
Authors: Ishchenko E A , Pasternak Yu G , Pendyurin V A , Rogozin E A , Fedorov S M 
Published: May 2021

Abstract
The paper presents a design of pyramidal horn antenna with an active metamaterial integrated in its structure, which allows controlling the direction of antenna radiation in the frequency range from 10.5 to 11 GHz while maintaining a high level of antenna performance and directivity. Pin diodes are used as switching devices located at the nodes.
Optimization of management of scientific departments in departmental organizations
Authors: Kalach A V , Zybin D G , Buharov O E , Baturo A N , Martinovich N V 
Published: May 2021

Abstract
In the paper current types of the organizational management structures have analyzed as well as typical problems of scientific departments are considered and organizational structure is proposed allowing optimization of management for the research center in the frames of organization in a law enforcement agency.
Modeling the solution of some management problems using latent variables
Authors: Kuzmenko R V , Stepanov L V , Moiseev S I , Sysoeva T P , Lukin A N 
Published: May 2021

Abstract
Original approaches to the solution of some common management problems with the use of latent variables are proposed in the work. Calculations of the values of the latent variables in the Rasch model is based on the least squares technique thus allowing to perform computations with the use of standard application packages.
Analysis and investigation of the conservativeness condition in the problem of parametric identification of distributed dynamic processes
Authors: Matveev M G , Sirota E A 
Published: May 2021

Abstract
The problem of bias of OLS estimates arises when solving the problem of parametric identification of distributed dynamic processes. There are various possible solutions to this problem. If the time series is trend-stationary, then these may be “ostationation” methods, which are generally difficult to apply. It is possible to use dimensionality reduction methods, but in this case we will still get biased estimates. In our previous works, it was shown that the problem of biased estimates can be solved using the conservativeness condition. The aim of this work was to investigate the possibility of using the conservativeness condition to improve the quality of estimates of the parametric identification problem, as well as to compare these results with the solution of the problem, in the case of applying a filter to it, as well as ridge regression.
Information support for decision-making in emergency situations
Authors: Nemtinov V , Kalach A , Egorov S , Nemtinova Y 
Published: May 2021

Abstract
In this article, the technology of information support for decision-making in the event of natural and technogenic emergencies is considered. Its implementation was carried out using the created information system (IS) for predicting the consequences of emergency situations, which is based on a single information space of the territory of the subject of the Russian Federation. The paper proposes an approach to creating an IS based on a distributed, peer-to-peer architecture when information resources (in relation to the considered IS) are not only presented as data, but also as various applications of basic ISs. A geographical information system is used as a basic one for solving problems of forecasting development and consequences of emergency situations. The decision support subsystem meets the following requirements: provides forecasts of occurrence and development of emergency situations in the form of predictive bulletins for review and approval of the management; provides paperwork for submission to rapid response services. Calculation of consequences of emergency situations is based on the following methods: assessment of consequences of accidents at explosive and fire-hazardous objects; forecasting and assessment of medical consequences of accidents at explosive and fire-hazardous objects; predicting the extent of contamination with highly toxic substances in accidents (destruction) at hazardous chemical facilities and transport; predicting possible accidents, catastrophes, and natural disasters; assessing damage from man-made, natural and terrorist emergencies, as well as classifying and recording them.
Study of performance and assessment of the state of higher nervous activity of the human operator in the “man-display” system
Authors: Novikova N M 
Published: May 2021

Abstract
The paper discusses the psychophysiological characteristics that describe the state of the nervous system of a human operator when working with a display. Special attention is paid to such characteristics of the nervous system as emotional stability and information transmission rate in the oculomotor system. Methods for measuring these characteristics using digital and literal texts are presented. The measurements were performed using a device developed by the author. The results of the performed experiments make it possible to solve the problem of occupational selection of operators with appropriate characteristics.