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A general approach to constructing gradient methods for parameter identification based on modified weighted Gram – Schmidt orthogonalization and information-type discrete filtering algorithms
Computer Research and Modeling, 2025, v. 17, no. 5, pp. 761-782The paper considers the problem of parameter identification of discrete-time linear stochastic systems in the state space with additive and multiplicative noise. It is assumed that the state and measurements equations of a discrete-time linear stochastic system depend on an unknown parameter to be identified.
A new approach to the construction of gradient parameter identification methods in the class of discrete-time linear stochastic systems with additive and multiplicative noise is presented, based on the application of modified weighted Gram – Schmidt orthogonalization (MWGS) and the discrete-time information-type filtering algorithms.
The main theoretical results of this research include: 1) a new identification criterion in terms of an extended information filter; 2) a new algorithm for calculating derivatives with respect to an uncertainty parameter in a discrete-time linear stochastic system based on an extended information LD filter using the direct procedure of modified weighted Gram – Schmidt orthogonalization; and 3) a new method for calculating the gradient of identification criteria using a “differentiated” extended information LD filter.
The advantages of this approach are that it uses MWGS orthogonalization which is numerically stable against machine roundoff errors, and it forms the basis of all the developed methods and algorithms. The information LD-filter maintains the symmetry and positive definiteness of the information matrices. The algorithms have an array structure that is convenient for computer implementation.
All the developed algorithms were implemented in MATLAB. A series of numerical experiments were carried out. The results obtained demonstrated the operability of the proposed approach, using the example of solving the problem of parameter identification for a mathematical model of a complex mechanical system.
The results can be used to develop methods for identifying parameters in mathematical models that are represented in state space by discrete-time linear stochastic systems with additive and multiplicative noise.
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Probabilistic aspects of “computer analogy” method for solving differential equations
Computer Research and Modeling, 2009, v. 1, no. 1, pp. 21-31Views (last year): 3. Citations: 1 (RSCI).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.
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Introduction to the parallelization of algorithms and programs
Computer Research and Modeling, 2010, v. 2, no. 3, pp. 231-272Views (last year): 53. Citations: 22 (RSCI).Difference of software development for parallel computing technology from sequential programming is dicussed. Arguements for introduction of new phases into technology of software engineering are given. These phases are: decomposition of algorithms, assignment of jobs to performers, conducting and mapping of logical to physical performers. Issues of performance evaluation of algorithms are briefly discussed. Decomposition of algorithms and programs into parts that can be executed in parallel is dicussed.
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Accuracy control for fast circuit simulation
Computer Research and Modeling, 2011, v. 3, no. 4, pp. 365-370Citations: 1 (RSCI).We developed an algorithm for fast simulation of VLSI CMOS (Very Large Scale Integration with Complementary Metal-Oxide-Semiconductors) with an accuracy control. The algorithm provides an ability of parallel numerical experiments in multiprocessor computational environment. There is computation speed up by means of block-matrix and structural (DCCC) decompositions application. A feature of the approach is both in a choice of moments and ways of parameters synchronization and application of multi-rate integration methods. Due to this fact we have ability to estimate and control error of given characteristics.
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Regularization, robustness and sparsity of probabilistic topic models
Computer Research and Modeling, 2012, v. 4, no. 4, pp. 693-706Views (last year): 25. Citations: 12 (RSCI).We propose a generalized probabilistic topic model of text corpora which can incorporate heuristics of Bayesian regularization, sampling, frequent parameters update, and robustness in any combinations. Wellknown models PLSA, LDA, CVB0, SWB, and many others can be considered as special cases of the proposed broad family of models. We propose the robust PLSA model and show that it is more sparse and performs better that regularized models like LDA.
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Subsystem “Developer” as a part of the Retail Payment System
Computer Research and Modeling, 2013, v. 5, no. 1, pp. 25-36In this paper we consider one of the core subsystems of the retail payment system named “Developer”. The Queuing System for modeling this subsystem was developed and information about it is provided. The task for the assignment problem was set up and solved (the modification of the Hungarian algorithm was used). Information about Agent Based Model for subsystem “Developer” and the results of the simulation experiments are given.
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Criteria and convergence of the focal approxmation
Computer Research and Modeling, 2013, v. 5, no. 3, pp. 379-394Methods of the solution of a problem of focal approximation — approach on point-by-point given smooth closed empirical curve by multifocal lemniscates are investigated. Criteria and convergence of the developed approached methods with use of the description, both in real, and in complex variables are analyzed. Topological equivalence of the used criteria is proved.
Keywords: curves, approximation, lemniscates, foci, criterion of curves nearness, basic, shape, invariant, algorithm, freedom degrees.Views (last year): 2. -
Parametric study of the thermodynamic algorithm for the prediction of steady flame spread rate
Computer Research and Modeling, 2013, v. 5, no. 5, pp. 799-804Views (last year): 1. Citations: 1 (RSCI).The stationary flame spread rate has been calculated using the relationship based on the thermodynamic variational principle. It has been shown that proposed numerical algorithm provides the stable convergence under any initial approximation, which could be noticeably far from the searched solution.
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About quality of Kernel based object tracking
Computer Research and Modeling, 2014, v. 6, no. 4, pp. 495-502The kernel based object tracking algorithms were described that take in account the independent changes of the 4 and 5 out of 5 parameters of the elliptic tracking region. It is shown that in tracking this conditions are sufficient and attempts of prediction are not necessary.
Keywords: automatic tracking, kernel based object tracking.Views (last year): 4. Citations: 2 (RSCI). -
Formation of optimal control of nonlinear dynamic object based on Takagi–Sugeno model
Computer Research and Modeling, 2015, v. 7, no. 1, pp. 51-59Views (last year): 2.The algorithm of fuzzy control system essentially nonlinear dynamic object is considered in this article. For solving nonlinear optimal control problem is proposed to use the method of linear quadratic regulation (LQR) with fuzzy Takagi–Sugeno model. The algorithm can be used for the design of deterministic optimal control of nonlinear objects. The algorithm of optimal control for controlling the rotational motion of a space vehicle is proposed.
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