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IEEE NW Russia Young Researchers in Electrical and Electronic Engineering Conference (EIConRusNW)

作者： Aleksandra V. Tutueva Ekaterina A. Rodionova Dmitrii O. Pesterev Artur I. Karimov Maria N. Kozak Department of Computer Aided Design Saint Petersburg Electrotechnical University "LETI" St. Petersburg Russia Youth Research Institute Saint Petersburg Electrotechnical University "LETI" St. Petersburg Russia

ISBN: (数字)9781728157610

ISBN: (纸本)9781728157627

computer simulation of systems described by ordinary differential equations imposes a number of requirements to the numerical solvers. One of the most important is a computational efficiency. To evaluate it, usually the maximal error of the numerical solution and the calculation time are used. The most common ways to integrate differential equations are single-step and multistep methods. Single-step integration demonstrates better stability and accuracy. However, such methods slower than multistep counterparts. Thus, both approaches are not optimal according to the mentioned criteria. The hybrid solver that combines the advantages of both integration approaches is seen as prospective. In this article, we consider such solver based on switching between two integrators. The choice of method depends on local error analysis of the obtained numerical solution. Numerical experiments show that such solver is effective for simulation of non-stiff systems described by ordinary differential equations.

关键词： Switches Error analysis Ordinary differential equations Numerical stability Stability analysis Mathematical model Chaos

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CdS Nanocrystallines: Synthesis, Structure and Nonlinear Optical Properties

arXiv

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arXiv 2022年

作者： Yanchuk, Oleksandr Marchuk, Oleg V. Myronchuk, Galyna Moroz, Iryna A. Andrushchak, Nazariy Vyshnevskyi, Oleksii A. Kityk, Iwan V. Kityk, Andriy V. Ozga, Katarzyna Jedryka, Jaroslaw Wojciechowski, Artur Andrushchak, Anatoliy Department of Inorganic and Physical Chemistry Lesya Ukrainka Eastern European National University Lutsk Ukraine Department of Materials Science Lutsk National Technical University Lutsk Ukraine Department of Computer-Aided Design Systems Lviv Polytechnic National University Lviv Ukraine M.P.Semenenko Institute of Geochemistry Mineralogy and Ore Formation NAS of Ukraine Kyiv Ukraine Faculty of Electrical Engineering Czestochowa University of Technology Czestochowa Poland Department of Telecommunication Lviv Polytechnic National University Lviv Ukraine

We report the synthesis, structure and nonlinear optical properties of cadmium sulphide (CdS) nanocrystallines (NCs) synthesized electrochemically both with and without detergent ATLAS G3300. Relevant structural and morphological features are explored by X-ray diffraction and scanning electron microscopy (SEM) techniques. The efficiency of the second harmonic generation (SHG) appears to be strongly dependent on the energy density of the incident fundamental laser radiation and NC sizes. © 2022, CC BY.

关键词： Cadmium sulfide

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Implication of effective length factor on multi-storied reinforced concrete building design 7

Implication of effective length factor on multi-storied rein...

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7th Nirma University International Conference on Engineering: Technologies for Sustainable Development, NUICONE 2019

作者： Purohit, Sharadkumar Jogani, Rutvi Ashokbhai Department of Civil Engineering School of Engineering Institute of Technology Nirma University Ahmedabad India Computer Aided Structural Analysis and Design Department of Civil Engineering School of Engineering Institute of Technology Nirma University Gujarat Ahmedabad India

ISBN: (纸本)9780367337377

Strength and stability are two key aspects of multi-storied Reinforced Concrete (RC) building design. While strength aspect has been given a due importance and is well understood, stability aspect in design is most underrated. Specially, structural design offices accepts codal based values of Effective Length Factor, k, to ensure stability of designed multi-storied RC buildings. Proper estimation of factor ‘k’, thus become important and an integral part of structural design of RC buildings. The present study aim towards realistic determination of effective length factor, k, for multi storied RC building. Implication of effective length factor, k, on structural design of a RC building is studied through geometric parameters like Stiffness Ratio, Inter-storey Drift and Maximum displacement and through design parameters like Axial Force and Bending Moment. It has been observed that, most of the commercial soft wares uses the value for effective length, k, as a unity i.e., 1 and warrants P-Δ effect making building frame as a non-sway frame. However, k-value varies largely and depends on joint stiffness ratio between column-beam. © 2020 Taylor & Francis Group, London, ISBN 978-0-367-33737-7

关键词： Structural design

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The modified Newton attraction law and its connection with cosmological Λ–term

arXiv

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arXiv 2020年

作者： Fimin, Nikolay N. Chechetkin, V.M. Keldysh Institute of Applied Mathematics of RAS 125047 Miusskaya sq. 4 Moscow Russia Institute of Computer Aided Design of RAS 123056 2nd Brestskaya st. 19/18 Moscow Russia

We consider the possibility of generalizing the Newtonian law of gravity and the transition to a general relativistic model for weak fields with the inclusion of a repulsive term identified as a cosmological constant. The analysis includes that of the test particle’s motion in a modified gravitational field of the Hilbert metric and then the problem of the reverse transition from the post–Galilean case to the construction of a modified exact point mass metric which includes the Λ–term. Copyright © 2020, The Authors. All rights reserved.

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Multiband and Wideband Chaotic Waveforms for Hydroacoustics

Multiband and Wideband Chaotic Waveforms for Hydroacoustics

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IEEE NW Russia Young Researchers in Electrical and Electronic Engineering Conference (EIConRusNW)

作者： Timur I. Karimov Olga S. Druzhina Georgii Y. Kolev Valery S. Andreev Denis N. Butusov Department of Computer Aided Design Saint Petersburg Electrotechnical University "LETI" St. Petersburg Russia Youth Research Institute Saint Petersburg Electrotechnical University "LETI" St. Petersburg Russia

ISBN: (数字)9781728157610

ISBN: (纸本)9781728157627

Signals currently used in sonars, namely, chirp signals, have several drawbacks in practical applications, such as strong attenuation over long distances and high influence of crosstalk. In this paper, we propose novel signal types, namely, multi-harmonic and chaotic signals. A comparative analysis of their application effect is performed in case of a limited-band sonar. It is shown that the characteristics of the sonar can be improved using these novel types of signals.

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The use of continuous and discrete markers for solving hydrodynamic problems with movable interface boundaries

The use of continuous and discrete markers for solving hydro...

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International Conference on 50 years of the development of grid-characteristic method, GCM50 2018

作者： Burago, Nikolay G. Nikitin, Alexander D. Nikitin, Ilia S. Ishlinsky Institute for Problems in Mechanics of the RAS 101-1 Prosp. Vernadskogo Moscow Moscow119526 Russia Institute of Computer Aided Design RAS 19/18 2-Ya Brestskaya Ul Moscow123056 Russia

ISBN: (纸本)9783030062279

Algorithms and results of continuous and discrete markers methods application to the problem of heavy viscous fluid flows calculations with free boundaries are described. The three-dimensional non-stationary Navier-Stokes equations and finite element method are used in variational formulation. An interface capturing method is implemented using fixed-grid with a continuous marker-function and (alternatively) discrete Lagrangian markers. The marker-functions have jumps at the interfaces and the interface boundary is detected as a level surface with intermediate value of marker-function. In numerical solutions, such way to detect interface boundary may result in the conservation laws violation even if conservative numerical methods are used. In order to prevent such effects in our algorithms the procedures of marker-function antidiffusion and conservation laws correction are introduced. In addition, in algorithms an immediate removal of possible monotonicity violations is used. Another implemented way to capture moving interfaces is based on the use of discrete Lagrangian markers. In addition to classic variant of the Marker And Cell (MAC) method, the algorithms of creation of new markers and removal of old markers at input and output boundaries are used. It allows us to consider the problems with open boundaries at long times. The improved interpolation at interface boundaries is described. The methods of continuous and discrete markers are used to simulate some set of incompressible viscous fluid flows with moving free boundaries and variable topology of solution region (joining and separation of parts of solution region). The solutions for following flows are presented: (1) falling water drop into water basin, (2) the flow of water from floor to floor through the hole, (3) the collapse of a water column and the oscillations of a fluid in a closed basin, (4) a fountain and a puddle from a vertical jet, and (5) fall of horizontal jets into the pool with water. © 2019,

关键词： Floors

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Hydrodynamic simulation of laser-induced shock waves using the Turbulence Problem Solver software package

引用

Journal of Physics: Conference Series 2021年第1期2057卷

作者： V V Shepelev S V Fortova Institute for Computer-Aided Design (ICAD RAS) 19/18 2nd Brestskaya St. Moscow Russia

The problem of irradiation of a semi-infinite bulk metal target by a single laser pulse, being important for many lase technology applications, is considered. The model for simulating the propagation and attenuation of shock waves, occurring when metals are irradiated with single laser pulse, is presented. The paper describes the computational algorithm based on the model and features of its implementation in C++ in a software package Turbulence Problem Solver (TPS) for modeling a wide class of problems described by hyperbolic equations. The problem is modeled using different approaches and the results are compared. The object-oriented polymorphic architecture of the software complex accelerates and facilitates the process of model development and calibration, allowing for flexible configuration and combination of elements of numerical models: Riemann solvers, various types of and reconstructions, and equations of state of matter.

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Analysis of IIR Filters by Interval Response

Analysis of IIR Filters by Interval Response

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2020 Moscow Workshop on Electronic and Networking Technologies, MWENT 2020

作者： Borges, Vinicius Nepomuceno, Erivelton G. Tutueva, Aleksandra V. Karimov, Artur I. Duque, Carlos Karimov, Timur I. Federal University of São João Del-Rei Electrical Engineering Department São João del-Rei Brazil Petersburg Electrotechnical University Computer Aided Design Department Saint-Petersburg Russia Petersburg Electrotechnical University Youth Research Institute Saint-Petesburg Russia Federal University of Juiz de Fora Power Electronics and Automation Group Juiz de For a Brazil

ISBN: (纸本)9781728125718

The classical theory of signal processing assumes that the designed IIR filters are continuous and have infinitely accurate coefficients. However, when developing filters for real-world digital signal processing tasks, it is necessary to take into account the finite precision of the coefficients representation, especially considering the fixed-point arithmetic. In this paper, we propose a new approach, which we call the interval size approach, making it easy to evaluate the actual digital filter response for various fixed-point arithmetic parameters. We provide Illustrative examples to demonstrate the frequency response bounds evolution as an order, cutoff frequency, and signal frequency are varying. We show that the interval size can be used as a well-suited accuracy factor of a digital filter. © 2020 IEEE.

关键词： Fixed point arithmetic

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Development of a mesoscale mechanical model of ceramic materials with multiscale porosity. Silica refractory case study

引用

AIP Conference Proceedings 2023年第1期2899卷

作者： E. V. Shilko A. S. Grigoriev A. A. Lapshina A. S. Buyakov V. V. Shmakov A. I. Dmitriev A. V. Zabolotskiy K. Andreev Laboratory of Computer-Aided Design of Materials Institute of Strength Physics and Materials Science SB RAS Tomsk 634055 Russia Faculty of Physics Tomsk State University Tomsk 634050 Russia Magnezit Group Satka Chelyabinsk region 456910 Russia Wuhan University of Science and Technology Wuhan 430081 China

The paper is devoted to the development of the mesoscopic mechanical model of porous silica refractory ceramics. The model takes into account the complex morphology of pore structure (channel-type pores and closed round pores) and pore size distribution within several orders of magnitude. Large (mesoscopic) pores are considered explicitly, while small (microscopic) pores concentrated near the interfaces between fine grains are effectively modelled as planar defects in the skeleton. The model was implemented within the numerical method of homogeneously deformable discrete elements. Using computer simulation, we studied the influence of the porosity value on the elastic and strength characteristics of representative volume elements (mesoscopic samples) of refractory. An analysis of the simulation results showed that microscopic defects have a significant influence on the mechanical behavior and macroscopic mechanical properties of the refractory, although the volume fraction of microscopic porosity is insignificant.

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Novel Composition ODE Solver based on Semi- Implicit Integration

Novel Composition ODE Solver based on Semi- Implicit Integra...

引用

International Conference on Soft Computing and Measurements (SCM)

作者： Artem A. Terentev Denis N. Butusov Petr S. Fedoseev Computer-Aided Design Department Saint Petersburg Electrotechnical University “LETI” St. Petersburg Russian Federation Youth Research Institute Saint Petersburg Electrotechnical University “LETI” St. Petersburg Russian Federation

ISBN: (数字)9781728196923

ISBN: (纸本)9781728196930

Semi-implicit numerical integration is an efficient approach to the solution of ordinary differential equations. In this paper, we study the applicability of semi-implicit schemes to the computer simulation of biological neuron taking the Hindmarsh-Rose system as an example. We propose a novel semi-implicit ODE solver based on the composition of three adjoint basic Euler-Cromer methods. The proposed approach uses the preliminary correction of the numerical solution obtained due to the reversibility of the basic method. The mathematical description and analytical order proof of the proposed method are given. The numerical efficiency of the semi-implicit integration techniques is investigated in comparison with well-known 2 nd order solvers: Runge-Kutta 2 method, explicit and implicit midpoint methods, and nonlinear integrator based on Pade approximation. We explicitly show that semi-implicit techniques possess better performance while simulating nonautonomous neuron models.

关键词： Biological system modeling Hafnium Mathematical model Neurons Computational modeling Numerical models Differential equations

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