共查询到20条相似文献,搜索用时 31 毫秒
1.
The problem of separation of the basic component of an experimental spectrum is considered. An algorithm is described that constructs a stable approximation to the solution by introducing constraints on the measure of variation of the basic component. Applications of the algorithm for the construction of the basic component of a quasi-experimental spectrum are considered.Translated from Matematicheskoe Modelirovanie i Reshenie Obratnykh Zadach Matematicheskoi Fiziki, pp. 76–81, 1993. 相似文献
2.
V. I. Dmitriev 《Computational Mathematics and Modeling》1997,8(3):270-277
We consider the inverse sounding problem for a stratified medium using the variable magnetic field of a loop. A uniqueness
theorem and a theorem ensuring stable determination of the integral conductivity of the medium are proved. An algorithm is
proposed for the solution of the inverse problem based on a transformation from the time domain to the frequency domain.
Translated from Obratnye Zadachi Estestvoznaniya, Published by Moscow University, Moscow, 1997, pp. 87–95. 相似文献
3.
E. E. Malyutina 《Computational Mathematics and Modeling》1999,10(4):393-404
A genetic algorithm is applied to compute the control of a complex dynamic system. Methods are proposed to modify the genetic
algorithm so as to adapt it to variation of the objective function. Comparison with dynamic programming results is carried
out.
The study was supported by the Russian Foundation of Basic Research (grant No. 9607-89110) and Ministry of Science (grants
0201.03.002 and 0201.03.003).
Translated from Chislennye Metody i Vychislitel'nyi Eksperiment, Moscow State University, pp. 82–96, 1998. 相似文献
4.
V. I. Dmitriev A A. Kantsel’ E. S. Kurkina N. V. Peskov 《Computational Mathematics and Modeling》2009,20(2):122-143
We present a mathematical model of underground leaching by solutions filtering through a porous medium. The model describes
the motion of solutions from injection to extraction boreholes, as well as dissolution and secondary deposition in reduced-pH
regions. A numerical algorithm has been developed for solving the problem on a plane in the general case of a homogeneous
medium that contains regions with various nonhomogeneities. The algorithm combines triangulation of the region with the finite
element method. The model also allows slow variation over time of some of the process parameters, such as porosity and the
filtration coefficient. Numerical results are reported for various cases. The model qualitatively describes the main regularities
of underground leaching and can be used to study and understand the detailed dynamics of these processes. The model also fills
gaps in geological prospecting data, and extraction curves constructed for different wells can be applied to determine the
approximate location of a particular nonhomogeneity. Mathematical modeling can help to optimize mineral extraction by underground
leaching.
Translated from Prikladnaya Matematika i Informatika, No. 29, pp. 29–55, 2008. 相似文献
5.
An algorithm is proposed to find the constrained minimum of a function. The algorithm uses differential equations that incorporate
the problem constraints as singular manifolds.
Translated from Obratnye Zadachi Estestvoznaniya, Published by Moscow University, Moscow, 1997, pp. 48–51. 相似文献
6.
Josef Dick. 《Mathematics of Computation》2007,76(260):2077-2085
In this paper we introduce a construction algorithm for extensible polynomial lattice rules and we prove that the construction algorithm yields generating vectors of polynomials which are optimal for a range of moduli chosen in advance. The construction algorithm uses a sieve where the generating vectors are extended by one coefficient in each component at each step and where one keeps a certain number of good ones and discards the rest. We also show that the construction can be done component by component.
7.
A linear operator equation of the first kind is investigated. The solution of this equation contains singularities of various types; namely, along with a smooth background, the solution has sharp bends and jump discontinuities. For the construction of a stable approximated solution, a modified Tikhonov method with a stabilizer in the form of the sum of three functionals is proposed. Each of the functionals accounts for the specific character of the corresponding component of the solution. Convergence theorems are formulated, a general discrete approximation scheme of the regularizing algorithm is justified, and results of numerical experiments are discussed. 相似文献
8.
A. G. Fokin 《Mechanics of Composite Materials》1973,9(3):445-449
A method has been developed, based on the random field theory, for the calculation of the elastic properties of reinforced media. The solution is obtained in the form of an operator series, each term of which is based on the formal component of the second derivative of Green's tensor of incompatibility equations. The zero (singular) approximation of such a series takes into account the local part of interactions between the inhomogeneity grains. The singular approximation was used to calculate the elasticity moduli of unidirectionl reinforced materials.Moscow Institute of Electronics. Translated from Mekhanika Polimerov, Vol. 9, No. 3, pp. 502–506, May–June, 1973. 相似文献
9.
A. A. Frolov E. V. Chizhonkov 《Computational Mathematics and Mathematical Physics》2017,57(11):1808-1821
A numerical asymptotic model for the breaking of two-dimensional plane relativistic electron oscillations under a small deviation from axial symmetry is developed. The asymptotic theory makes use of the construction of time-uniformly applicable solutions to weakly nonlinear equations. A special finite-difference algorithm on staggered grids is used for numerical simulation. The numerical solutions of axially symmetric one-dimensional relativistic problems yield two-sided estimates for the breaking time. Some of the computations were performed on the “Chebyshev” supercomputer (Moscow State University). 相似文献
10.
The direct solution of the vertical electrical sounding problem is considered for three-dimensional quasilayered media. An
efficient fast algorithm is obtained for computing the apparent resistivity curves in the two-dimensional case. A PC implementation
of the algorithm is proposed.
Translated from Obratnye Zadachi Estestvoznaniya, Published by Moscow University, Moscow, 1997, pp. 123–131. 相似文献
11.
A. V. Motavkin L. L. Shcheglov N. G. Egorov B. S. L'vov 《Mechanics of Composite Materials》1969,5(2):237-244
A mechanical model of the interaction between the reinforcing elements and the polymer matrix is proposed for glass-reinforced plastics with a random distribution of the reinforcing elements. On the basis of this model, a theoretical relation is obtained for the variation of the strength utilization factor with increase in the fiber length-to-diameter ratio, with allowance for the glass-to-resin ratio and the elastic characteristics of the components. The theoretical calculations are found to be in satisfactory agreement with the experimental data.All-Union Scientific-Research Institute of Glass-Reinforced Plastics and Glass Fiber, Moscow Region. Moscow Bauman Higher Technical College. Translated from Mekhanika Polimerov, Vol. 5, No. 2, pp. 288–297, March–April, 1969. 相似文献
12.
The article presents a procedure and results of numerical analysis of the structure of flow near an elongated cylinder with
a spherically blunted nose that moves with a supersonic velocity with local injection of gas from its lateral surface. The
analysis is based on the solution of the full Navier-Stokes equations for a compressible gas. Nonstationary fluctuations in
the region of the condensation discontinuity are detected in the given range of Mach and Reynolds numbers.
Translated from Chislennye Metody v Matematicheskoi Fizike, Published by Moscow University, Moscow, 1996. pp. 119–124. 相似文献
13.
V. I. Maksimov 《Computational Mathematics and Modeling》1997,8(3):217-225
The problem of estimating the right-hand side of a nonlinear parabolic equation is considered. A finite-step algorithm based
on the model positional control method and the finite element method is proposed. The algorithm is robust to informational
noise and computational errors.
Translated from Obratnye Zadachi Estestvoznaniya, Published by Moscow University, Moscow, 1997, pp. 23–33. 相似文献
14.
It is suggested to consider the structure of a filled polymer as a set of two or more multifractals. It is shown experimentally that the basic factor determining the fractal dimension of distribution of a disperse filler in the polymer is the size distribution of filler particles.Moscow State Open University, Moscow, Russia. Translated from Mekhanika Kompozitnykh Materialov, Vol. 35, No. 3, pp 269–290, 1999. 相似文献
15.
E. V. Zakharov S. N. Levchenko Yu. Ya. Kharlanov 《Computational Mathematics and Modeling》1997,8(3):282-287
The article considers the mathematical model of a lens antenna in the shape of a homogeneous dielectric torus excited by an
axial magnetic dipole. The boundary-value problem for an elliptical differential equation is posed and reduced by the fundamental
solution method to an integral equation of 2nd kind over the torus section. A numerical algorithm is proposed, and the numerical
results are compared with experimental findings.
Translated from Obratnye Zadachi Estestvoznaniya, Published by Moscow University, Moscow, 1997, pp. 109–115. 相似文献
16.
V. F. Apel'tsin 《Computational Mathematics and Modeling》1997,8(3):245-253
The article compares two approaches to continuation of solutions of external boundary-value problems for the Helmholtz equation
outside the original region in the solution space — analytical continuation and the generalized image method. The comparison
focuses on naturalness and ease of use of the mathematical model for the construction of numerical algorithms.
Translated from Chislennye Metody v Matematicheskoi Fizike, Published by Moscow University, Moscow, 1996, pp. 68–79. 相似文献
17.
Using a model of local interactions an asymptotic theory is constructed for the plane motion of a slender sharpened body of revolution when it is fully immersed in a dense medium and there is no flow separation at the lateral surface. Assuming that at the initial instant of time the dynamic component of the normal stress is much greater than the tensile strength, the domain of variation of the governing, parameters corresponding to asymptotically stable types of motion is found for translational motion of a body at zero angle of attack. 相似文献
18.
Roberto Cavoretto 《Journal of Computational and Applied Mathematics》2010,234(5):1505-5966
In this paper a new efficient algorithm for spherical interpolation of large scattered data sets is presented. The solution method is local and involves a modified spherical Shepard’s interpolant, which uses zonal basis functions as local approximants. The associated algorithm is implemented and optimized by applying a nearest neighbour searching procedure on the sphere. Specifically, this technique is mainly based on the partition of the sphere in a suitable number of spherical zones, the construction of spherical caps as local neighbourhoods for each node, and finally the employment of a spherical zone searching procedure. Computational cost and storage requirements of the spherical algorithm are analyzed. Moreover, several numerical results show the good accuracy of the method and the high efficiency of the proposed algorithm. 相似文献
19.
A simple mathematical model of the motion of a parachute system in space is described and an interactive algorithm for parametric identification of the model is proposed. The algorithm selects the model parameters that minimize the deviation of the calculated dependences from experimental observations on the computer graphic monitor.Moscow. Translated from Dinamicheskie Sistemy, No. 10, pp. 106–111, 1992. 相似文献
20.
The paper considers the problem of determining the velocities of targets in the atmosphere given a set of Doppler spectra produced by continuous Doppler systems. The problem of determining the velocities of particles moving in a closed trajectory (a circle) is examined. A uniqueness theorem is proved for the reconstruction of velocities from two spectra. An algorithm is proposed for determining the sought function, and a numerical experiment is conducted to establish its efficiency.Translated from Matematicheskie Modeli Estestvoznaniya, Published by Moscow University, Moscow, 1995, pp. 162–167. 相似文献