Математика, механика, информатика. Рубрика в журнале - Сибирский аэрокосмический журнал
Статья научная
Feature selection is a quite important step in data analysis. Extracting relevant attributes may not only decrease the dimensionality of the dataset and, consequently, reduce time costs spent on the next stages, but also contribute to the quality of the final solution. In this paper we demonstrate some positive effects of the usage of a heuristic feature selection scheme which is based on a two-criterion optimization model. The approach proposed is applied to the speech-based emotion recognition problem, which is currently one of the most important issues in human-machine interactions. A number of high-dimensional multilingual (English, German, Japanese) databases are involved to investigate the effectiveness of the technique presented. Three different multi-objective genetic algorithms and their cooperative modifications are applied as optimizers in combination with classification models such as a Multilayer Perceptron, a Support Vector Machine and Logistic Regression. In most cases we may observe not only a dimensionality reduction, but also an improvement in the recognition quality. To avoid choosing the most effective multi-objective genetic algorithm and the best classifier, we suggest applying a heterogeneous genetic algorithm based on several heuristics and an ensemble of diverse classification models.
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Multigrid finite elements in the calculations of multilayer cylindrical shells
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An effective numerical method for calculating linearly elastic multilayer cylindrical shells under static loading implemented on the basis of Finite Element Method (FEM) procedures using the multilayer curved Lagrangian multi- grid finite elements (MFE) of the shell type was proposed. Such shells are widely used in rocket-space and aircraft engineering. MFE are developed in local Cartesian coordinate systems based on small (basic) shell partitions that take into account their heterogeneous structure, irregular shape, combined loading and fixing. The stress strained state (SSS) in the MFE was described by the equations of the three-dimensional elasticity problem without using the addi- tional kinematical and static hypotheses, which allow one to use MFE for the shells of various thicknesses to be calcu- lated. The procedure of constructing the Langrage polynomials in local curvilinear coordinate systems used to develop the shell MFE is presented. The displacements in the MFE were approximated by the power and Lagrange polynomials of different orders. When constructing a n -grid finite element (FE), n ≥ 2, n-nested grids were used. The fine grid was generated by the basic partition of the MFE; the other (coarse) grids were used to reduce its dimension. According to the method, the nodes of the coarse MFE grids are located on the common boundaries of the different modular layers of the shell. The proposed law of the expansion in the number of discrete models using MFE with a constant thickness, multiple of the shell thickness, provides a uniform and rapid convergence of approximate solutions, allowing one to frame solutions with a small error. Multigrid discrete models have 103…106 times less unknown MFE than the basic ones. The implementation of the MFE for multigrid models requires 104…107 times less computer storage space than for the reference models, which allows one using the proposed method to calculate some large shells. An example of calculating a multilayer cylindrical local loading shell of irregular shape was given. In the calculation, three-grid shell - type FE, developed on the basis of the reference models having from 2 million to 3.7 billion of the nodal MFE unknowns were used. To study the approximate solution convergence and error, a well-known numerical method was used.
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Multilingual technology. System aspects of its organization and usage
Статья научная
System aspects of multilingual adaptive-training technology organization and usage to train multilingual vocabulary are considered. Information vocabulary support of the technology is presented. Its realization is directed at the architectural layer of rules primary, corresponded to the functions of adaptive-training model and multilingual term basis.
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New exact solutions which describe 2-dimensional velocity field for Prandtl’s solution
Статья научная
New velocity fields are found for the well-known Prandtl's solution which describes pressing of a thin layer of plastic material between two parallel stiff and rough plates. The method of construction of other velocity fields is considered.
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Non-parametric algorithms of reconstruction of mutually ambiguous functions from observations
Статья научная
We consider the task of reconstruction of the regression function from observations with errors. Under parametric uncertainty conditions this problem is solved in the following sequence: first the type of regression function with accu- racy to parameters is set, then the next stage is the estimation of these parameters based on training sample elements. The main problem that arises is choosing a parametric structure, i. e. the choice of parameters with an accuracy to the vector of parameters. At the same time more or less inaccuracy can be allowed, descriptions of many variables func- tions with accuracy to parameters cause particular difficulties. Another known way of solving such problems, which is the nonparametric estimation of regression function from observations, in this case the stage of choosing a parametric equation of the regression function is missing. A number of publications is devoted to this area including monographs where the results are in most cases related to the asymptotic properties of the regression function. The article considers the task of reconstruction of mutually ambiguous functions of many arguments from observa- tions with random errors in the conditions of nonparametric uncertainty. This problem has been insufficiently studied, although it has a significant importance in the identification and control of objects of a Wiener and Hammerstein class. The control theory widely uses already known mutually ambiguous specifications that describe the work of items with a loop of hysteresis, backlashes and others. Some modifications of nonparametric estimates of mutually ambiguous fea- tures including multidimensional are given. A series of computing experiments have been conducted where for simplic- ity reasons the simpliest mutually ambiguous curves were taken, parametric structure of these curves for the algorithms was unknown, only observation was known. Numerical studies covered two cases: different sample sizes and various disturbances affecting the studied processes. The reconstruction of mutually ambiguous dependency plays an important role in the development of robots and various robotic systems moving on in an undefined or unknown terrain. As sepa- rate blocks the considered algorithms can be useful in devices that are used in the aerospace industry.
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Numerical investigation of the problem of cohesive running soils punching shear
Статья научная
A special mathematical model generalizing the classical model of the elasticity theory is used for the analysis of directions of the deformations localization in samples of soils with different strengths. Numerical solution of the problems is carried out by means of iterative process, the equations of the elasticity theory with initial stresses being solved on each step thereof on the basis of the finite-element method.
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OLAP-технология как средство мониторинга образовательного процесса
Статья научная
Без тщательного мониторинга образовательного процесса в высшем учебном заведении невозможно всесторонне оценить достижения студента. В целях мониторинга предложено использовать технологию многомерного анализа данных OLAP. Рассмотрен пример внедрения OLAP-технологии в учебный процесс на уровне дисциплины.
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Статья научная
The possibility of factorial analysis application in theestimation of the state of information systems security is considered. The procedure of selection and classification of factors as well as calculation of factors influence on the resultant indicator size are described.
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On classes of functions with binary variables
Статья научная
The scheme proposed below is often used for solving problems and developing optimization algorithms. To solve a specific problem an efficient algorithm of optimization has been developed. The proposed algorithm combines several classes of problems by generelasing and determining a function class. For this reason establishing correlation among available classes of functions with binary variables in different experiments allows to apply even not perfect optimization algorithms. In this paper we consider a question on correlation of the function classes based on the different approaches to classification itself. First approach offers classes of separable, modular and submodular function; second one offers function classes based on structural features of the set of binary variables: monotone, unmonotone and w eakly unmonotone functions. It has been proven that separable functions are always unimodal and monotone ones. The results obtained in this study will allow to use a more efficient algorithm for optimization of separable and modular functions.
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On nonparametric algorithms of object groups control
Статья научная
The paper is devoted to the identification and control of a group of both identical and varied objects. First the con- trol system of a local object is considered. Further on, all random factors acting in the measurement channels of an object are omitted and only the relationships between objects are preserved. Nonparametric algorithms of identification and control are given in a rather general form. The main attention is paid to different relationships between local objects. First the simplest case is considered, that is, a serial technological chain for whose control it is offered to use an external circuit of control when control influences in an external circuit play the role of a setting influence of local systems. The group of objects of a parallel-serial type is the following in complexity and here some feature inherent in many variables figuring in the corresponding section of a group of objects shows itself. This essential feature is that the output variables are measured with different discreteness, and the discreteness of control can significantly vary, includ- ing hours, shifts, days and weeks, depending on the nature of the production process and the scheme of measurement and control of corresponding variables. For example, the fineness of grinding in the production of cement is measured several times per shift, and the activity of cement showing its brand is determined only after 28 days. This circumstance should be taken into account when developing computer systems for identification, control and decision-making. The most difficult are such groups that fit into the scheme of interrelated objects, where feedback takes place in the technological process. The external control circuit can have a hierarchical structure, where the number of hierarchies is related to technical-economic, production-economic factors and in active systems to social factors as well. Control of such complexes is a complicated task, where the application of the theory of adaptive and learning systems is justified. This paper considers a class of algorithms of a non-parametric type, i.e. algorithms oriented to the case when informa- tion for describing objects is insufficient for parameterization, i.e. selection up to a set of vector parameters. Similar algorithms are presented in a rather general way. As a result, some cases of using control systems for groups of objects for thermal power plants are considered, and condensed information is provided for the metallurgical processing of the Norilsk Combine.
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On nonparametric control of a dynamic system
Статья научная
The paper considers the problem of dual control of an inertia-free object whose input is affected by a control vari- able and an observable but uncontrollable variable. The idea of dual control belongs to A. Feldbaum and was devel- oped on the basis of Bayesian approach. In this case, the probability densities of interference, as well as input output variables are known. In particular, the case of Gaussian probability densities was investigated. As a result, algorithms of dual control with the simplest objects of the inertia-free class were obtained. In the case of combined control systems, these studies were carried out by Feldbaum’s followers. Further development of dual control theory was described by Y. Tsypkin. The probability density of the interference was unknown, but the stage of selecting the structure of the control device and the equation of the describing object were necessary. In Tsypkin’s works, the corresponding parametric algorithms for dual control are given. In this case, a simultaneous estimation of the coefficient of the model and the regulator was made on the basis of the method of sto- chastic approximations. Later on nonparametric dual control algorithms were proposed. It is this way of control design that is discussed in the current paper. The parametric model of the object and the parametric structure of the controller were unknown in the problem statement. Nevertheless, it was known from a priori information that the characteristic of the object was one-to-one in control. Below we consider nonparametric control algorithms that combine the processes of simultaneous control and the study of the object with an accuracy of the structure unknown to the parameters, but a priori with a given number of delayed elements of the output variable of the object. In other words, the depth of the memory of the managed object was determined. In this case, a nonparametric algorithm for dual control can function in conditions of passive and active accumulation of information. The technique for representing a one-dimensional inertial-free dynamic system to a multidimensional static one is presented in the paper. Some results of numerical investigation of nonparametric algorithms of dual control are also presented.
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On nonparametric identification and dual control of quasilinear dynamic processes
Статья научная
The problems of identification and control of stochastic objects with a discrete - continuous technological process nature under conditions of nonparametric indeterminacy are considered. This term means a situation when the process structure with the accuracy to within parameters remains unknown. A more general class of dynamical nonlinear proc- esses, later of quasilinear processes, is investigated. The processes in this category are characterized by a low degree of nonlinearity, that is the superposition principle for this type of object is insolvent. Such processes often occur in vari- ous control loops for aerospace objects and systems. Nonparametric models where the dynamic process memory depth is specified on the basis of the selection of essential variables rule are given. According to this rule, the only variables included in the nonparametric model, at which the optimum blurring factor of the kernel is minimal. Nonparametric algorithms of quasilinear objects dual control are given. Control devices built on the basis of these algorithms not only perform the object control function directly, but also its study. The case when the control device corresponding to its inverse model “turns on” at the object input is considered. The process of dual control system training with active information accumulation is analyzed. The results of a numerical study of nonparametric models for quasilinear proc- esses with memory are presented in detail, as well as the results of a computational experiment using the algorithm of nonparametric adaptive dual control. In the simulation, objects characteristics were described by equations with different degrees of nonlinearity, the form of which was unknown, and which, during active information accumulation, were automatically restituted on the basis of the input-output variables process measurement. Also, the influence of various noise levels affecting an object and in measurement channels was investigated. The given computational ex- periments confirmed the possibility of using nonparametric algorithms for identifying and controlling of quasilinear systems.
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On properties of knapsack systems of information protection with the open key in ZP
Статья
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Orbital ordering probed by electron-spin resonance method in magnetic semiconductors
Статья научная
The temperature dependence of the electron-spin resonance in the 80300 K range temperature and magnetic field up to 5 kOe has been investigated in the substance of CoхMn1-хS solid solutions. From the temperature dependence of linewidth and g-value the orbital order is determined. The temperature hysteresis of ESR intensity in CoхMn1-хS is found at the cooling in the magnetic field and without it.
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Статья научная
In the given work the problem of semantic decompression patterns addition to the meaningful sentences generated as functions in multidimensional vector space of the notions of the natural language is considered. The model of adding semantic decompression patterns based on stylistically-oriented sets of generative grammar rules is offered. The complexity of natural language translation problem is discussed. The considered model provides the algorithm of adding semantic decompression patterns that can be used for improving the performance of educational tasks generation software.
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Properties of locally cyclic groups
Статья научная
Locally cyclic group is a group every finite set of elements of which generates a cyclic subgroup. We give examples of periodic locally cyclic groups and locally cyclic torsion-free groups. Properties of locally cyclic groups are studied. A locally cyclic group cannot be mixed, that is, it cannot contain elements of finite and infinite order simultaneously. A locally cyclic group is Abelian. By their properties periodic locally cyclic groups and locally cyclic torsion-free groups are distinguished. The Sylow subgroups of a periodic locally cyclic group are cyclic or quasi-cyclic. A periodic locally cyclic group decomposes into a direct product of Sylow subgroups. By N. F. Sesekin and A. I. Starostin the fol- lowing theorem is proved: a locally finite group, all Sylow p-subgroups of which are quasi-cyclic, is a complete peri- odic locally cyclic group. Here, in addition to this theorem, we consider the structure of a complete periodic locally cyclic group. A complete periodic locally cyclic group decomposes into a direct product of quasi-cyclic subgroups with distinct prime numbers. A complete periodic locally cyclic group is uniquely reconstructed by its lower layer. In this article an example is given of the fact that an arbitrary periodic locally cyclic group is not unique reconstructed by its lower layer. A torsion-free locally cyclic group is isomorphic to a subgroup of the additive group of rational numbers. A periodic locally cyclic group is layer-finite, that is a number of it’s elements of each order is finite. A locally cyclic group can be either a layer-finite or a subgroup of additive groups of rational numbers. The results can be applied when encoding information in space communications.
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Research into the methods of software product developing and maintaining
Статья научная
Currently the development of information and Open Source technologies for the implementation of critical business functions in fields of national economy, including space industry becomes relevant. However, as experience shows there is no uniform method for the process of developing and operating the software product using Open Source technology. The aim of the article is to study classical and modern models and technologies of software analysis and design. It will help choose the optimal model for the development of the method for creating a prototype information system using Open Source technology, and also to define the design environment and the tasks of implementing the prototype of the information system. The article considers a summary table which allows to choose efficient model for developing the method of building the information system, taking into account the specifics of the free software products.
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Research of the semi-Markovian process in conditions of limitedly rare changes in its state
Статья научная
In this work the SM-flow in conditions of limitedly rare changes in its states is considered. In the proposed asymptotic condition there is a probable distribution of a number of events coming from the SM-flow in time t. We have shown that this distribution can be multimodal.
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Researches of hybrid technology of the noncontact acoustic control
Статья научная
This work is devoted to the results of experimental research concerning noncontact acoustic control of products. An advanced method of ultrasonic vibrations excitation in materials is offered. Design features of an electromagnetic acoustic converter for radiation – acoustic control are described.
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Results of computing experiments for water ecological system mathematical modeling
Статья научная
The point-wise imitation and one-dimensional mathematical models of aquatic ecosystems have been overlooked. The developed models are intended for studying ecosystems in the Krasnoyarsk aquatic basin and in separate locations on the Yenisei River. The results of the computing experiments are presented.
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