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Khairetdinov M.S.,Novosibirsk State Technical University | Kovalevskiy V.V.,Institute of Computational Mathematics and Mathematical Geophysics
2016 Dynamics of Systems, Mechanisms and Machines, Dynamics 2016 | Year: 2016

Monitoring of the natural and technogenic environment is one of the most important priority directions in the development of science and technologies. A major problem here is the prediction and prevention of ecological risks for the environment caused by the action of destructive natural and technogenic events and processes. For this purpose a fundamentally new, ecologically clean, and high-resolution method is active vibrational monitoring. It involves tracking of the temporal dynamics of boundary lithosphere-atmosphere' media in response to the action of metrologically precise sounding oscillations of seismic vibrators. The process of excitation of wave fields by such vibrators is accompanied by complex physical phenomena in the source zone, which continue at considerable distances from it. These include nonlinear processes of interaction between the source and the medium and those of radiation of conjugate wave oscillations (seismic, acoustic, electric, and electromagnetic ones). Analysis of these phenomena and estimation of their quantitative characteristics are of purely scientific and practical value. In this paper, original results of experiments aimed at solving the above problems are presented. © 2016 IEEE.

Rodionov A.,Institute of Computational Mathematics and Mathematical Geophysics | Migov D.,Institute of Computational Mathematics and Mathematical Geophysics | Rodionova O.,Novosibirsk State University
IEEE Transactions on Reliability | Year: 2012

This paper contains some algorithms and recommendations that enable increasing efficiency of cumulative updating of all-terminal reliability for a network with unreliable links. The existence of cutnodes, 2-node cuts, and chains in a network structure can be used for faster calculations. © 2012 IEEE.

Plotnikov M.Y.,RAS Institute of Thermophysics | Shkarupa E.V.,Institute of Computational Mathematics and Mathematical Geophysics
Computers and Fluids | Year: 2012

In this work the problem of selection of a number of numerical parameters of the direct simulation Monte Carlo (DSMC) method (such as time step, cell size, and number of time steps) is addressed. We study the errors of the DSMC method relating to the quality and amount of information sampled during simulation for three main macroparameters of a gas flow (density, velocity, and temperature). The expressions for optimal selection of the sampling time step, the number of sampling cells, and the sample size which guarantee attaining a specified level of the error are proposed on the basis of the theory of functional Monte Carlo algorithms. Practical recommendations are given for evaluating the quantities involved in the expressions simultaneously with the calculation of the flow macroparameters. The proposed approaches are examined on the examples of the Fourier problem, the gas recondensation problem between two infinite parallel plates, and the supersonic plane-parallel rarefied gas flow around a flat plate. © 2012 Elsevier Ltd.

Fatyanov A.G.,Institute of Computational Mathematics and Mathematical Geophysics | Terekhov A.V.,RAS Budker Institute of Nuclear Physics
Journal of Computational Physics | Year: 2011

A high-performance parallel algorithm is proposed for modeling the propagation of acoustic and elastic waves in inhomogeneous media. An initial boundary-value problem is replaced by a series of boundary-value problems for a constant elliptic operator and different right-hand sides via the integral Laguerre transform. It is proposed to solve difference equations by the conjugate gradient method for acoustic equations and by the GMRES(k) method for modeling elastic waves. A preconditioning operator was the Laplace operator that is inverted using the variable separation method. The novelty of the proposed algorithm is using the Dichotomy Algorithm [26], which was designed for solving a series of tridiagonal systems of linear equations, in the context of the preconditioning operator inversion. Via considering analytical solutions, it is shown that modeling wave processes for long instants of time requires high-resolution meshes. The proposed parallel fine-mesh algorithm enabled to solve real application seismic problems in acceptable time and with high accuracy. By solving model problems, it is demonstrated that the considered parallel algorithm possesses high performance and efficiency over a wide range of the number of processors (from 2 to 8192). © 2010 Elsevier Inc.

Snytnikov N.V.,Institute of Computational Mathematics and Mathematical Geophysics
CEUR Workshop Proceedings | Year: 2016

We developed parallel algorithm for solving Vlasov-Poisson systems of equations using particle-in-cell method. It uses new technique of dynamic load balancing for processors, which are distributed between subdomains in correspndance with the number of modeling particles located in the subdomain. Domain decomposition method combines grid (eulerian) method for solving Poisson equation with lagrangian paricle method for solving Vlasov equation. It takes into account physical features of the modeling nonstationary rotating disks (both 2D and 3D).

Shakhov V.,Institute of Computational Mathematics and Mathematical Geophysics
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

Wireless Sensor Networks is considered as one of the most important elements in the upcoming Internet of Things. As sensors based applications are widely deployed, limited battery power of the sensor nodes becomes a serious problem. Intrusions or malfunction of legitimate sensor protocols can lead to the quick depletion of sensors batteries and a network failure. Energy harvesting facilities provide an attractive solution to this problem. The potential of the energy harvesting wireless sensor networks can be properly applied if the corresponding efficient network operations protocols will be implemented. Development of this protocols requires the corresponding mathematical tools for system performance evaluation. Most papers in this area focus on some concrete technical problem, but there is lack of papers analyzing common principles of energy harvesting wireless sensor networks operating. In this paper we partially fill this gap. © Springer International Publishing Switzerland 2016.

Marchuk A.G.,Institute of Computational Mathematics and Mathematical Geophysics
Science of Tsunami Hazards | Year: 2016

In this paper, the kinematics of tsunami wave rays and fronts over an uneven bottom are studied. A formula for the wave height along a ray tube is obtained. An exact analytical solution for wave rays and fronts over a sloping bottom is derived. This solution makes possible to determine a tsunami wave height in an area with a sloping bottom from the initial source in the ray approximation. The distribution of wave-height maxima calculated in an area with a sloping bottom is compared to that obtained with a shallow-water model. © 2016 - TSUNAMI SOCIETY INTERNATIONAL.

Afanasyev I.,Institute of Computational Mathematics and Mathematical Geophysics
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

A cellular automata model of population dynamics of eight organisms in Lake Baikal is proposed and investigated. The model allows to take into account spatial organisms distribution, seasonal dependency of birth rates, possible habitat pollution and water streams. Computational experiment is presented. It demonstrates that population dynamics tends to stable oscillating process with period equal to 1 year. The model was verified within production-to-biomass and frequency of occurrence ratios. © 2013 Springer-Verlag Berlin Heidelberg.

Kurbanmuradov O.A.,Turkmen State University | Sabelfeld K.K.,Institute of Computational Mathematics and Mathematical Geophysics
Transport in Porous Media | Year: 2010

A stochastic numerical method is developed for simulation of flows and particle transport in a 2D layer of porous medium. The hydraulic conductivity is assumed to be a random field of a given statistical structure, the flow is modeled in the layer with prescribed boundary conditions. Numerical experiments are carried out by solving the Darcy equation for each sample of the hydraulic conductivity by a direct solver for sparse matrices, and tracking Lagrangian trajectories in the simulated flow. We present and analyze different Eulerian and Lagrangian statistical characteristics of the flow such as transverse and longitudinal velocity correlation functions, longitudinal dispersion coefficient, and the mean displacement of Lagrangian trajectories. We discuss the effect of long-range correlations of the longitudinal velocities which we have found in our numerical simulations. The related anomalous diffusion is also analyzed. © Springer Science+Business Media B.V. 2010.

Terekhov A.V.,Institute of Computational Mathematics and Mathematical Geophysics
Parallel Computing | Year: 2013

In this study, we develop a new parallel algorithm for solving systems of linear algebraic equations with the same block-tridiagonal matrix but with different right-hand sides. The method is a generalization of the parallel dichotomy algorithm for solving systems of linear equations with tridiagonal matrices [1]. Using this approach, we propose a parallel realization of the domain decomposition method (the Schur complement method). The calculation of acoustic wave fields using the spectral-difference technique improves the efficiency of the parallel algorithms. A near-linear dependence of the speedup with the number of processors is attained using both several and several thousands of processors. This study is innovative because the parallel algorithm developed for solving block-tridiagonal systems of equations is an effective and simple set of procedures for solving engineering tasks on a supercomputer. © 2013 Elsevier B.V. All rights reserved.

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