Selection of optimal data placement using cloud infrastructure

Benefits of using cloud technology are obvious, their application is expanding, as a result, it determines the steady growth of demand. Cloud computing has acquired particular relevance for large companies connected with Internet services, retailing, logistics that generate large volume of business and other information. The use of cloud technologies allows organizing the joint consumption of resources, solving the problems of storing and transferring significant amounts of data. Russian consumer cooperation refers to large territory distributed organizations actively forming their own digital ecosystem. The issue of data storing and processing for consumer coo-peration organizations is very relevant. At the same time, the prices of cloud service providers are significantly different and require solving the problem of minimizing the cost of storing and transferring significant amounts of data. The application of the linear programming method is considered to select the optimal data storage scheme for several cloud service providers having different technical and economic parameters of the package (maximum amount of storage, cost of allocated resources). Mathematical model includes the equation of costs for data storing and transferring and restrictions on the amount of storage, the amount of data and its safety. Software tool that allows to perform numerical calculations is selected Microsoft Excel in combination with the "search for solutions" add-on. In accordance with the mathematical model, the conditions for minimizing the amount of cloud storage costs and the necessary restrictions are established. Initial data are set for three data forming centers, storages of certain size for five cloud service providers and nominal price for information storage and transmission. Calculations of expenses are performed in several variants: without optimization, with the solution of the optimization problem, with price increase by cloud service providers. Results of the calculations confirm the necessity to solve the problem of minimizing the cost of cloud services for corporate clients. The presented model can be expanded for any cost conditions as well as for different areas of cloud applications.

Energy parameters of the vehicle electromagnetic shock absorber

The creation of an electromagnetic shock absorber system is necessary taking into account such parameters of the vehicle and operating conditions as the quality of the roadway, the grades, and the weight and size of the vehicle. A mathematical simulation model of the vehicle was developed to determine energy indicators in various road sections. The MATLAB Simulink programming environment was chosen to create the most practical and functional simulation model. A number of experiments were carried out using various parameters of the vehicle, types of roadways and driving cycles. Simulation results allow obtaining basic characteristics of electromagnetic damper of the selected vehicle, on the basis of which a linear electromagnetic damper shock absorber will be calculated. System energy efficiency was determined when using a vehicle on roads having a different road surface evenness index.

Development of an effective accumulator battery with a voltage inverter in the electric energy storage unit

The article proposes a matching device between an accumulator battery and a voltage inverter in electric energy storage systems based on a reversible DC-DC converter with improved weight, size and cost indicators. Lithium-ion batteries are subject to tough operational requirements. The discharge of such batteries is not recommended to exceed their three-fold capacity (C), while the charge is limited to 0.5C, and low-frequency ripple components should not be present in the charging current. These requirements can be fulfilled with the help of the proposed matching device which is characterized by smaller dimensions and cost achieved due to the choke unit. The article proposes the calculation of the converter circuit and presents the simulation results obtained in the Psim simulation environment (the PowerSim environment). An economic assessment of the converter has been carried out.

Quantum properties of dielectric losses in nanometer layers of solid dielectrics at ultra-low temperatures

Using the methods of quasi-classical kinetic theory, continuum electrodynamics, and non-relativistic quantum theory, we construct and study the quantum kinetic equation of proton relaxation, which, together with the Poisson operator equation describes the mechanism of diffusion tunneling transport of hydrogen ions (protons) in the potential field of a crystal lattice perturbed by a polarizing field (quantum diffusion polarization) in crystals with hydrogen bonds. Using the apparatus of the density matrix (statistical matrix), by complete quantum-mechanical averaging of the polarization operator, studies are carried out of the experimental value of the polarization of the dielectric, as a function of the parameters of the external electric field (amplitude, frequency of electromotive force) and temperature. When calculating the equilibrium density matrix for an ensemble of basic relaxers (hydrogen ions), the proton-proton and proton-phonon interactions are not taken into account, and the Hamilton operator for the phonon subsystem is assumed to be a numerical constant for a given crystal under given experimental conditions (calculated by computer method as a parameter for comparing the theory with the experiment). The influence of the phonon subsystem on the kinetics of the relaxation process is reduced to a weak spatially homogeneous force field acting on protons moving in the field of the main forces of hydrogen bonds. The Hamilton of the proton subsystem is constructed for the model of an ideal proton gas in equilibrium with the ionic subsystem of the crystal lattice, and the equilibrium statistical operator of the proton subsystem is written using the Boltzmann quantum statistics. Theoretically, the size effects are found to be manifested in shifts of the low-temperature (50–100 K) maxima of the dielectric loss angle tangent towards ultra-low temperatures (4–25 K) with a decrease in the amplitudes of the maxima by 3-4 orders of magnitude, with a reduction in the thickness of the crystal layer from 1–10 microns to 1–10 nm. The effect of anomalous displacements of low-temperature maxima, which is explained by the abnormally high quantum transparency of the potential barrier for protons (0.8-0.9) in thin films of a crystal with hydrogen bonds (1-10 nm), causes, near the temperatures of the shifted maxima of dielectric losses (4–25 K), a quasi-ferroelectric state, which is also characterized by abnormally high values of the real component of the complete dielectric permittivity (2.5–3.5millions).

On electromagnetic radiation of individual charges

The aim of the study is to establish the conditions for synchrotron radiation based on significant differences between tangential and centripetal accelerations of electric charges. From the fact that electromagnetic radiation carries away energy, it follows that the energy of the radiating system changes during radiation. Related to this is the following well-known rule: a change in energy is equal to work done. Three relevant theorems are proved. Theorem 1 states that a tangentially accelerated electric charge emits electromagnetic waves. Theorem 2 states that a normally accelerated electric charge does not emit electromagnetic waves. It is a well-known circumstance that the centripetal force does not perform work (since the scalar product of orthogonal vectors must be equal to zero). The proofs of Theorems 1 and 2 are performed in terms of forces. For electric charges, the transition to the terms of accelerations is carried out in accordance with Theorem 3which states that an electric charge satisfies Newton's second law. The tangential acceleration of an electric charge leads to the emission of electromagnetic waves. Generalization of the phenomenon of radiation to acceleration in general, including. normal charge acceleration, is false. The cause of synchrotron radiation should be sought in the tangential acceleration due to Coulomb interactions between the beam charges.

Optimization of torque ripples in direct torque control drives

The article discusses the features of the synthesis of a hybrid method for commutation of a three-phase inverter in a classic version of drives with direct torque control (DTC), which involves the use of relay characteristics in the flux- and torque control blocks. It is proved that the output voltage of a converter based on a B6-inverter formed by only six basic vectors (excluding the zero vector) limits further optimization of flux- and torque ripples in the electrical motors. It has also been proven that with the classical drives with direct torque control, the torque ripples on the motor shaft are indeed higher than in systems with pulse width modulation. An analysis of the method was carried out which could allow reducing the amplitude of the torque ripples when drives with direct torque control are applied for motors supplied with only basic vectors of the inverter due to the modified (hybrid) method of inverter commutation. The conditions under which the hybrid control method of the inverter is really capable of reducing the amplitude of the motor flux- and torque ripples are considered. Based on the analysis of the proposed solution, the law of hybrid control of the inverter is presented by means of the formation of additional vectors of its output voltage via basic vectors of the inverter. The advantages of the method include the simplicity of drive control under development or in the existing drive control system, the implementation of which is carried out exclusively by a software product. With the absence of iterative methods of mathematics, the resources of microprocessor control units are reduced, which makes this method even more attractive in low-budget electrical drives that do not claim to be "high-end" of control blocks. The oscillograms are shown of a flux and current of motor with direct torque control motor application only with six base vectors of the output voltage of a semiconductor inverter and a drive with direct torque control by the hybrid method with additional voltage vectors based on the basic vectors of the inverter.

Simulation of thermal conductivity of rare gases by the stochastic method

One of the main successes of the kinetic theory of gases is the explicit calculation of the transport coefficients of rarefied gases. However, the greatest problems arise when calculating the thermal conductivity coefficient, especially for polyatomic gases. Also, when using different potentials, it is necessary to systematically calculate the so-called Ω-integrals, which in itself is a rather difficult task. For this reason, direct numerical molecular modeling of the processes of transfer of rarefied gases, in particular, the calculation of their transfer coefficients, is also relevant. A well-known method for such modeling is the molecular dynamics method. Unfortunately, until now this method is not available for modeling the processes of rarefied gas transfer. Under nor-mal conditions, the simulation cell should contain tens or even hundreds of millions of molecules during calculations. At the same time, the numerical implementation of the molecular dynamics method is accompanied by a systematic appearance of errors, which is the reason for the appearance of dynamic chaos. With this simulation, the true phase trajectories of the system under consideration cannot be obtained. Therefore, naturally, the idea of developing a method for modeling transport processes arises, in which phase trajectories are not calculated based on Newton's laws, but are simulated, and then are used to calculate any observables. In our works, we developed a method of stochastic molecular modeling (STM) of rarefied gas transfer processes, where this idea was implemented. The efficiency of the SMM method was demonstrated by calculating the coefficients of self-diffusion, diffusion, and viscosity of both monoatomic gases and polyatomic gases. At the same time, the possibility of modeling the most complex transfer process – the energy transfer process – has not yet been considered. This work aims to simulate the thermal conductivity coefficient by the SMM method. Both monoatomic (Ar, Kr, Ne, Xe) and polyatomic gases (CH4, O2) were considered.

Research and application of the crow search algorithm for geometric covering optimization problems

The problem of geometric covering is a special case of the optimal design problem and belongs to the class of cutting and packing problems. The challenge is to position some geometric objects on the surface to be coated so that the entire surface is covered. The complexity of the problems under consideration is due to their belonging to the class of NP-hard problems, which excludes the possibility of solving them by exact methods and requires the development of approximate optimization methods and algorithms. This article discusses the problem of geometric covering of an area with circles from a given set of radii. To solve the problem of geometric covering, a hexagonal grid coverage method with optimization by a metaheuristic algorithm is used. The crow search algorithm is such an algorithm, which is a relatively new metaheuristic algorithm based on the intelligent behavior of crows in a flock. The crow search algorithm includes two control parameters: the awareness probability and the flight length. To study the solution method and check the efficiency, a problem was modeled on the basis of a real design of automatic irrigation systems, and the results of experiments with different values of control parameters were presented.

The fluctuation-dissipation theorem and the autocorrelation function of thermal radiation

A new relatively simple derivation of the fluctuation-dissipation theorem (FDT) is presented. The generalized coordinate of the system is changed by an external force and is expressed by means of causal susceptibility, its Fourier transform – the transfer function, generalized impedance and active resistance. These characteristics describe heat dissipation on the resistor and the result is generalized to the dissipative system which is under the action of macroscopic force. The fluctuation voltage on the resistor is obtained by decomposing the thermal chaotic motion of free charges along the conductor into a Fourier series. The number of standing waves and the average energy of the quantum oscillation state at a fixed temperature give the thermal power of charge transfer. By comparing with the Joule-Lenz law and by generalizing the result to an arbitrary isothermal system, the mean square of the fluctuating force and dispersion of the generalized coordinate caused by the thermal motion are obtained. The autocorrelation functions of the generalized coordinate and the random force, and their spectral densities are expressed through the considered characteristics. The content of FDT is that the power of heat release, the spectral densities of the fluctuating force and the autocorrelation are proportional to the imaginary part of the transfer function of the system. The result is used for thermal radiation in a cavity the walls of which contain electric dipoles excited by thermal motion. The transfer function, the fluctuating force acting on the charge, the dispersion of the electric field strength, time autocorrelation of the electric field strength and its spectral density are obtained. Real and imaginary components, the modulus and phase are found for complex relative autocorrelation of the electric field strength and the coherence time is determined.

Structure and operation algorithm of the data collection module of the Super c-τ factory electromagnetic calorimeter

The study is devoted to the development of a data collection module of the electromagnetic calorimeter of the Super c-τ factory collider. The data collection module is one of the main parts of the data acquisition system of the electromagnetic calorimeter. It is designed for analog and digital signal processing of scintillation counters, calculating its main characteristics (amplitude, time of occurrence and quality of fitting), and participates in the launch of the detector data acquisition system. A prototype of the module on which the module will be debugged and the algorithm of the device will be checked is being developed. The algorithm of the module includes the calculation of signal characteristics and the formation of packets for data transmission. Signal characteristics are calculated by approximating a function defined either by the least squares method or by the method of χ2 function minimization. In the course of a mathematical experiment, it was found that the method of χ2 function minimization gave more accurate calculation values than the least squares method. However, it requires an experiment with scintillation counters to determine the necessary coefficients. Therefore, the coefficients of the approximating curve are determined by the least squares method in the proto-type and the method of χ2 function minimization is used in the module. Based on the results obtained, an algorithm of the module operation was compiled, which was then implemented in the field-programmable gate array Altera Cyclone 10GX.