Результаты поиска по 'Formalism':
Найдено статей: 46
  1. Koganov A.V.
    Agreement of Relation Theory and EPR Effect by individual state of quantum particle
    Computer Research and Modeling, 2015, v. 7, no. 1, pp. 3-34

    We consider effect of Einstein, Podolsky, Rosen in connection with quantum mechanic and relative theory. We sow that may introduce in quantum mechanic the individual state for quantum particle which eliminate the contradiction quantum mechanics with relative theory of type long-range action between correlated particles. In article we develop the apparatus for individual state introducing in quantum mechanic formalism and build the EPR effect model without contradictory. We describe the general mechanism of Bell inequalities infringement and analogical effects.

    Views (last year): 1.
  2. Editor’s note
    Computer Research and Modeling, 2024, v. 16, no. 7, pp. 1533-1538
  3. Matyushkin I.V.
    Cellular automata methods in mathematical physics classical problems solving on hexagonal grid. Part 2
    Computer Research and Modeling, 2017, v. 9, no. 4, pp. 547-566

    The second part of paper is devoted to final study of three classic partial differential equations (Laplace, Diffusion and Wave) solution using simple numerical methods in terms of Cellular Automata. Specificity of this solution has been shown by different examples, which are related to the hexagonal grid. Also the next statements that are mentioned in the first part have been proved: the matter conservation law and the offensive effect of excessive hexagonal symmetry.

    From the point of CA view diffusion equation is the most important. While solving of diffusion equation at the infinite time interval we can find solution of boundary value problem of Laplace equation and if we introduce vector-variable we will solve wave equation (at least, for scalar). The critical requirement for the sampling of the boundary conditions for CA-cells has been shown during the solving of problem of circular membrane vibrations with Neumann boundary conditions. CA-calculations using the simple scheme and Margolus rotary-block mechanism were compared for the quasione-dimensional problem “diffusion in the half-space”. During the solving of mixed task of circular membrane vibration with the fixed ends in a classical case it has been shown that the simultaneous application of the Crank–Nicholson method and taking into account of the second-order terms is allowed to avoid the effect of excessive hexagonal symmetry that was studied for a simple scheme.

    By the example of the centrally symmetric Neumann problem a new method of spatial derivatives introducing into the postfix CA procedure, which is reflecting the time derivatives (on the base of the continuity equation) was demonstrated. The value of the constant that is related to these derivatives has been empirically found in the case of central symmetry. The low rate of convergence and accuracy that limited within the boundaries of the sample, in contrary to the formal precision of the method (4-th order), prevents the using of the CAmethods for such problems. We recommend using multigrid method. During the solving of the quasi-diffusion equations (two-dimensional CA) it was showing that the rotary-block mechanism of CA (Margolus mechanism) is more effective than simple CA.

    Views (last year): 6.
  4. Bozhko A.N., Livantsov V.E.
    Optimization of geometric analysis strategy in CAD-systems
    Computer Research and Modeling, 2024, v. 16, no. 4, pp. 825-840

    Computer-aided assembly planning for complex products is an important engineering and scientific problem. The assembly sequence and content of assembly operations largely depend on the mechanical structure and geometric properties of a product. An overview of geometric modeling methods that are used in modern computer-aided design systems is provided. Modeling geometric obstacles in assembly using collision detection, motion planning, and virtual reality is very computationally intensive. Combinatorial methods provide only weak necessary conditions for geometric reasoning. The important problem of minimizing the number of geometric tests during the synthesis of assembly operations and processes is considered. A formalization of this problem is based on a hypergraph model of the mechanical structure of the product. This model provides a correct mathematical description of coherent and sequential assembly operations. The key concept of the geometric situation is introduced. This is a configuration of product parts that requires analysis for freedom from obstacles and this analysis gives interpretable results. A mathematical description of geometric heredity during the assembly of complex products is proposed. Two axioms of heredity allow us to extend the results of testing one geometric situation to many other situations. The problem of minimizing the number of geometric tests is posed as a non-antagonistic game between decision maker and nature, in which it is required to color the vertices of an ordered set in two colors. The vertices represent geometric situations, and the color is a metaphor for the result of a collision-free test. The decision maker’s move is to select an uncolored vertex; nature’s answer is its color. The game requires you to color an ordered set in a minimum number of moves by decision maker. The project situation in which the decision maker makes a decision under risk conditions is discussed. A method for calculating the probabilities of coloring the vertices of an ordered set is proposed. The basic pure strategies of rational behavior in this game are described. An original synthetic criterion for making rational decisions under risk conditions has been developed. Two heuristics are proposed that can be used to color ordered sets of high cardinality and complex structure.

  5. Andreeva A.A., Kazymov B.I., Lobanov A.I., Panyukov S.V., Yaremin B.I.
    Mathematical model of blood clotting in the portal vein
    Computer Research and Modeling, 2026, v. 18, no. 3, pp. 561-587

    Portal vein thrombosis (PVT) is a significant complication during both the pre-transplant and postoperative periods of liver transplantation. The multifactorial etiology of PVT, the paradoxical hemostatic state in liver cirrhosis and the limited usefulness of standard coagulation tests highlight the necessity of formalized models to assess thrombosis risk.

    Objective: Using a mathematical model of the blood coagulation system, investigate the influence of hemodynamic conditions and coagulation factor levels on the likelihood of thrombus formation in the portal vein.

    The portal vein is modelled as a flow-through reactor with rapid convective mixing. The mathematical model is based on Panteleev et al. (2010) detailed kinetic scheme, incorporating equations for the extrinsic pathway of coagulation activation, positive and negative feedback loops, and inhibition of active factors. The resulting system of ordinary differential equations was integrated using a one-stage Rosenbrock method with complex coefficients.

    Thrombin generation was shown to exhibit threshold dependence on blood flow velocity. Above a critical velocity, the initiation phase does not transition to the amplification phase. This corresponds to physiological conditions that prevent thrombus formation. We demonstrated that, at reduced fibrinogen concentrations characteristic of hepatic dysfunction, the critical velocity threshold above which thrombus formation is suppressed increases. This indicates the system’s heightened susceptibility to stasis. Protein C deficiency had minimal effect on thrombogenesis dynamics under the modeled conditions. The modeling results qualitatively agree with clinical data on fibrinogen distribution in PVT patients ($n$ = 932, Sklifosovsky Research Institute).

  6. Stroganov A.V., Aristov V.V.
    Probabilistic aspects of “computer analogy” method for solving differential equations
    Computer Research and Modeling, 2009, v. 1, no. 1, pp. 21-31

    Method which allows to obtain explicit form of the solution as a part of power series of the argument step is developed. Formalization of characteristics of the algorithm analogous to operations of a computer is performed. The operation of transfer from one rank to another leads to a probability scheme of the algorithm that averages unknown intermediate steps in higher ranks of the series. The stochastic characteristics of the method are studied and illustrated. Examples of solving nonlinear equations and systems of nonlinear differential equations are presented.

    Views (last year): 3. Citations: 1 (RSCI).
  7. Rezaev R.O., Trifonov A.Y., Shapovalov A.V.
    The Einstein−Ehrenfest system of (0, M)-type and asymptotical solutions of the multidimensional nonlinear Fokker−Planck−Kolmogorov equation
    Computer Research and Modeling, 2010, v. 2, no. 2, pp. 151-160

    Semiclassical approximation formalism is developed for the multidimensional Fokker–Planck–Kolmogorov equation with non-local and nonlinear drift vector with respect to a small diffusion coefficient D, D→0, in the class of trajectory concentrated functions. The Einstein−Ehrenfest system of (0, M)-type is obtained. A family of semiclassical solutions localized around a point driven by the Einstein−Ehrenfest system accurate to O(D(M+1)/2) is found.

    Views (last year): 2.
  8. Pechenyuk A.V.
    Benchmarking of CEA FlowVision in ship flow simulation
    Computer Research and Modeling, 2014, v. 6, no. 6, pp. 889-899

    In the field of naval architecture the most competent recommendations in verification and validation of the numerical methods were developed within an international workshop on the numerical prediction of ship viscous flow which is held every five years in Gothenburg (Sweden) and Tokyo (Japan) alternately. In the workshop “Gothenburg–2000” three modern hull forms with reliable experimental data were introduced as test cases. The most general case among them is a containership KCS, a ship of moderate specific speed and fullness. The paper focuses on a numerical research of KCS hull flow, which was made according to the formal procedures of the workshop with the help of CEA FlowVision. Findings were compared with experimental data and computational data of other key CEA.

    Views (last year): 1. Citations: 5 (RSCI).
  9. Kuznetsov M.B., Polezhaev A.A.
    The mechanism of formation of oscillons — localized oscillatory structures
    Computer Research and Modeling, 2015, v. 7, no. 6, pp. 1177-1184

    A formal model mechanism of oscillon formation is proposed. These structures were found in a variety of physical systems and a chemical Belousov–Jabotinsky reaction proceeding in an aerosol OT water-inoil microemulsion. Via the proposed mechanism oscillons occur as a result of interaction of two subsystems. In the first subsystem for a proper set of parameters solitary stationary structures may arise as a result of hard local excitation. These structures influence spatial distribution of the second subsystem parameter that leads to local oscillations in the subsystem.

    Views (last year): 6. Citations: 1 (RSCI).
  10. Ivanov S.D.
    Web-based interactive registry of the geosensors
    Computer Research and Modeling, 2016, v. 8, no. 4, pp. 621-632

    Selection and correct applying of the geosensor — the instrument of mineral geothermobarometry is challenging because of the wide variety of existing geosensors on the one hand and the availability of specific requirements for their use on the other. In this paper, organization of the geosensors within the computer system called interactive registry was proposed for reducing the labor intensity of the geosensors usage and providing information support for them. The article provides a formal description of the thermodynamic geosensor, as a function of the minerals composition and independent parameters, as well as the basic steps of pressure and temperature estimation which are common for all geosensors: conversion to the formula units, calculation of the additional parameters and the calculation of the required values. Existing collections of geosensors made as standalone applications, or as spreadsheets was examined for advantages and disadvantages of these approaches. Additional information necessary to use the geosensor was described: paragenesis, accuracy and range of parameter values, reference and others. Implementation of the geosensors registry as the webbased application which uses wiki technology was proposed. Usage of the wiki technology allows to effectively organize not so well formalized additional information about the geosensor and it’s algorithm which had written in a programming language into a single information system. For information organization links, namespaces and wiki markup was used. The article discusses the implementation of the applications on the top of DokuWiki system with specially designed RESTful server, allowing users to apply the geosensors from the registry to their own data. Programming language R uses as a geosensors description language. RServe server uses for calculations. The unittest for each geosensor allows to check the correctness of it’s implementation. The user interface of the application was developed as DokuWiki plug-in. The example of usage was given. In the article conclusion, the questions of the application security, performance and scaling was discussed.

    Views (last year): 5.
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