DSpace Собрание:
http://hdl.handle.net/11701/2479
2019-06-16T03:31:37ZNumerical methods for solving optimal control for Stefan problems
http://hdl.handle.net/11701/2528
Название: Numerical methods for solving optimal control for Stefan problems
Авторы: Nekrasov, Sergej A.; Volkov, Vladimir S.
Краткий осмотр (реферат): The article describes the mathematical model and a numerical method for the calculation
and optimization of temperature fields with regard to phase transformations and the nonlinear
material properties. It proposes a finite-difference method and a computer program that will
effectively implement the computer simulation and optimization of thermal processes during
melting and crystallization of the product. Direct Stefan problem was solved on the basis of
one of the options through “enthalpic” method. The solution of the dual problem is found by
smoothing the concentrated heat capacity and other parameters and characteristics of a feature
such as a delta function. The article deals with a number of examples of optimization problems
under various restrictions: minimizing energy consumption for melting the material, finding the
maximum (minimum) temperature field, as well as two-sided estimate gradient of the solution
at a given point in the area. In the above case, the functions of control are the source of the
bulk power density, the values of which are located in a strip of arbitrary width. The results can be used in the practice of research and design in the field of metallurgy, electrical appliances,
сryogenic etc. Refs 12. Figs 7. Tables 3.2016-06-01T00:00:00ZThe influence of available capacity distribution type and fines on the optimal plan of the available capacity of the hydroelectric power plant
http://hdl.handle.net/11701/2527
Название: The influence of available capacity distribution type and fines on the optimal plan of the available capacity of the hydroelectric power plant
Авторы: Budylin, Mikhail A.; Sokolov, Sergei V.
Краткий осмотр (реферат): The article deals with the optimal hydroelectric power available capacity planning
considering the distribution of available capacity and the penalty for difference between actual
and planned available capacity. It is assumed that the available capacity may be characterized
by different types of symmetrical distributions, and the penalty can range from 0 to ∞
of the difference between actual available capacity and planned. The planned value of the
available capacity is determined, which maximizes the financial results of the hydroelectric
power plants on the wholesale electricity market. Suggestions were made for available capacity
planning optimization. A software package for calculating the optimal plan of available capacity
hydroelectric power is developed. Refs 8. Figs 2.2016-06-01T00:00:00ZQuadrocopter control in emergency mode
http://hdl.handle.net/11701/2526
Название: Quadrocopter control in emergency mode
Авторы: Baranov, Oleg V.
Краткий осмотр (реферат): In this paper the concept of quadrocopter control in emergency mode problem is introduced
and considered. Emergency control mode for the autonomous UAV can be characterized
primarily by the difficulty or impossibility of receiving signals from global satellite navigation
systems. This can happen if the UAV falling into the electromagnetic field of various technical
objects, in dense urban or high mountains, and also in arctic regions. In the military area,
presence of the special regime is dictated by the possibility of using electronic warfare devices.
Several different approaches to solving the problem is offered. The results of numerical
simulation of the emergency landing using a quality criteria are presented. The scheme of
spoofing the navigation signal by integrating inertial measurement unit without hardware
modification is proposed. Refs 17. Figs 4.2016-06-01T00:00:00ZEfficiency assessment of clinical decision support system
http://hdl.handle.net/11701/2525
Название: Efficiency assessment of clinical decision support system
Авторы: Kupeeva, Irina A.; Raznatovskiy, Constantine I.; Ravodin, Roman A.; Karelin, Vladimir V.; Bure, Vladimir M.; Gusarov, Mikhail V.
Краткий осмотр (реферат): In the article the authors developed an intelligent decision support system for medical
solutions (ISPPVR) on dermatology, received the name “Logoderm”. This system has a modular structure and is able to perform an automated analysis of dermatologic diseases’ symptoms. The
introduction of intelligent decision support system for medical solutions to practical medicine
can provide significant economic benefits, as it will relieve patients from having to carry out
costly flights from the cities and towns of the country to the small number of large cities, in
which there are the leading medical centers from that medical field. The article with the help
of statistical analysis conducted study of the efficiency of the developed system. The possibility
of the practical using of this system is proved. Refs 8. Table 1.2016-06-01T00:00:00ZSpecialized container library for purposes of vector graphics dynamic displaying
http://hdl.handle.net/11701/2524
Название: Specialized container library for purposes of vector graphics dynamic displaying
Авторы: Kalinin, Dmitriy V.; Orekhov, Mikhail Yu.
Краткий осмотр (реферат): This paper considers instrumental support issues of complex technological objects modelling
on the level of container library design for the purposes of vector object-oriented 2D open-text
formatted schemes real-time dynamic displaying. Guaranteed rapid key-string search allows
presenting the graphical objects as variable structures — string-indexed associative containers of
mutable-typed attributes, simplifying visualization system development and maintenance under
simulated objects types and dynamic behavior patterns indeterminacy condition. Displaying
system efficiency becomes critically dependent from attribute key-string look-up duration as
modelled object complexity increases and reveals in great amount of scheme graphical objects,
reaching several thousands. Besides this feature, container library must answer some other
specific requirements. This article enumerates them and suggests applicable implementation.
The present paper also adduces the results of test, estimating insertion and look-up speed,
performed for designed container class and its analogues provided by STL and Qt. Refs 12.
Figs 4.2016-06-01T00:00:00ZOn the choice of equivalent stress for the problem of mechanochemical corrosion of spherical members
http://hdl.handle.net/11701/2523
Название: On the choice of equivalent stress for the problem of mechanochemical corrosion of spherical members
Авторы: Sedova, Olga S.; Pronina, Yulia G.
Краткий осмотр (реферат): This paper compares two models of double-sided mechanochemical wear of thick spherical
members subjected to inner and outer pressure. The corrosion rates on the inner and outer
surfaces of the sphere are supposed to be linear functions of the corresponding equivalent
stress. The possible inhibition of the corrosion process is taken into account. One of the models
compared uses the von Mises stress as the equivalent stress while another model uses the
maximum principal stress as the equivalent stress. The effect of hydrostatic pressure on the
durability of the sphere is investigated. It is shown that, unlike the first model, the second one
reflects the effect of hydrostatic pressure. Within the model using the maximum principal stress,
the durability may be considerably smaller or larger, depending on the sign of the difference between the inner and outer pressure. It is demonstrated that when the inhibition constant is
not equal to zero, the difference between the durability calculated by the use of one model and
the durability calculated by the use of another may reach hundreds percent. It is shown that
for high-pressure vessels in the conditions of corrosion the maximum principal stress model is
more appropriate then the von Mises stress model. Refs 30. Figs 3.2016-06-01T00:00:00ZRepeated eigenvalues of a matrix with elements polynomially dependent on a parameter
http://hdl.handle.net/11701/2522
Название: Repeated eigenvalues of a matrix with elements polynomially dependent on a parameter
Авторы: Kalinina, Elizaveta A.
Краткий осмотр (реферат): Earlier matrices with multiple eigenvalues were considered only for theoretical purposes.
However, now such non-generic matrices are also of practical interest because they appear in
different problems of quantum mechanics, nuclear physics, optics and dynamic of mechanical
systems. A square matrix with elements that are linearly dependent on a parameter is considered
in this paper. A method to find the values of the parameter such that the matrix has a repeated
eigenvalue is considered. We find the polynomial whose roots are these values of the parameter
using only finite number of algebraic operations on the matrix elements. The method can be
generalized to matrices with elements algebraically dependent on a parameter. A numerical
example of how to find the required parameter values is considered. Refs 16.2016-06-01T00:00:00ZA criterion of existence and uniqueness of the Lyapunov matrix for a class of time delay systems
http://hdl.handle.net/11701/2521
Название: A criterion of existence and uniqueness of the Lyapunov matrix for a class of time delay systems
Авторы: Egorov, Alexey V.
Краткий осмотр (реферат): The Lyapunov matrix for systems of linear time-delay equations is a matrix-valued function
which is a solution of a special dynamic system with some additional boundary conditions.
This matrix allows to construct the complete type Lyapunov–Krasovskii functionals with a
prescribed derivative, which are used successfully in analysis of behavior of time-delay systems.
It was shown in works of Kharitonov and Chashnikov that the Lyapunov condition, that is
the absence of opposite eigenvalues of the system, guarantees the existence and uniqueness
of the Lyapunov matrix for systems of retarded type with multiple delays and for systems of
neutral type with a single delay. In this contribution, we consider a linear time-invariant system
of neutral type with two delays. It is shown that under a certain constraint the Lyapunov
condition, that is the absence of opposite eigenvalues of the system, is also a criterion of the
existence and uniqueness of the Lyapunov matrix. Refs 14.2016-06-01T00:00:00ZThe problem of estimation of the moment of time of the event occurrence for quadratic loss function
http://hdl.handle.net/11701/2520
Название: The problem of estimation of the moment of time of the event occurrence for quadratic loss function
Авторы: Bure, Artem V.
Краткий осмотр (реферат): Evaluation of the time moment of the appearance of some events on the available statistical
information is of considerable interest. In medicine, agricultural physics, reliability theory, risk
analysis problems of this type arise often. The various restrictions on the choice of the moment
time can be taken by virtue of the specific characteristics of this problem. One of the possible
approaches to solving these problems is the use of fines and loss functions. In this paper we
considered the quadratic loss. Different levels of awareness are considered and the optimal
estimates are found. For unknown distribution function we suggest a minimax approach and
the optimal solution is found also. Defective probability distributions are considered in the
paper. Defective probability distributions are used in applied problems in medicine, in reliability
theory, in risk analysis. Refs 6.2016-06-01T00:00:00Z