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We have considered a problem on the propagation of shear horizontally polarized surface waves in the framework of a piezoelectric structure with an inhomogeneous coating from a functionally graded material. We assume that physical properties of the coating change in a piecewise continuous way. As a base material of the structure, we use a piezoelectric of hexagonal syngony with a 6mm class symmetry...
The problem of optimal authorization of a user in a system with a role-based access control policy is considered. The main criterion is to minimize the risks of permission leakage. The choice of the role for authorization is based on the analytic hierarchy process. The substantiation of a choice of criteria for formation of a hierarchy of the first level is given. An algorithm for calculating weight...
The goal of any technical modernization of production is to improve economic performance. For the metallurgical industry, this is a reduction in the kWh / tonne. One effective way is to implement FACTS-devices. An important stage in the course of design work is the calculation of the payback period of the implemented equipment. Approved methodology of feasibility study shows a good result.
Modal filters (MFs) based on multiconductor microstrip lines are investigated for the first time in the frequency domain. The frequency dependences of |£21| up to 10 GHz are obtained. Both computational and full-scale experiments are used. A printed circuit board with prototypes of multiconductor MFs are presented. Two-, three-, four- and five-conductor MFs are investigated. The computational experiment...
The ladder filters based on microelectronic BAW resonators with a Bragg reflector are designed. The BAW resonator represents a piezoelectric transducer based on zinc oxide films with thin-film electrodes of aluminum films and a Bragg reflector consisting of four pairs Mo-Al and one pair Mo-SiO2. The ladder filter topology based on the single T-shaped link consisting of three SMR is presented. The...
The article describes one of the Data Assimilation methods application based on the Kalman filter application. The application in forecasting the Ensemble Kalman Filter is shown by the Lorenz attractor model. Errors were taken into account in carrying out the experiment for both the model and the forecasting. The effect of model and filter parameters on the forecasting quality were estimated. As a...
A new class of graphs is introduced in preferential attachment random graphs theory, these graphs are grown by adding an infinite number of complex stochastic increments, consisting of several interconnected vertices. The problems of final degree distributions for vertices and edges of growing graphs are solved by analytic methods. Analytic solution of a graph calibration (synthesis) problem due to...
The paper considers the principle of stabilization for the rotation speed with the use of a magnetic CVT in the form of a magnetic gearbox providing the required reduction coefficient. The paper is devoted to investigations of transients in a autonomous power system consisting of wind turbines with synchronous generators with permanent magnets under sudden change wind speed. The investigation involves...
Traditionally, the using an analog-to-digital conversion demands agreeing with the requirements of Shannon, Nyquist and Kotel'nikov theorem. According to this theorem, the frequency of the conversion should, at least, twice exceed the upper boundary frequency of the spectrum of the converted signal. It is also traditionally considered that the presence of high-frequency noises of more than one quantization...
Derivation of signals is often required to control various dynamic objects [1–8]. Derivation allows increasing the stability of the system, since it allows to react not only to the actual increase in the control error, but also to take into account the tendency of growth or reduction of this error. Derivation increases the margin of stability in phase. There are methods of designing regulators based...
A mathematical model of control stations total power losses and efficiency for centrifugal pumps feeding submersible motors for the oil extraction was developed. The model makes possible to calculate separate components of these power losses. A simplified, convenient for application model of total power losses and efficiency values is proposed depending on the output current of control stations and...
The urgency of reliable navigation for manned and self-driving vehicles in urban environment is growing. The de facto standard of mass-produced navigation systems is global navigation satellite system (GNSS). Standalone work of a GNSS receiver is possible while receiving at least 4 signals from different navigation satellites. Operating of GNSS receiver in an "urban canyon" is broken due...
Radio communication channels for the transmission of discrete messages are typically affected by various types of additive and multiplicative interferences resulting in non-stationary radio lines. The quality of such radio line changes over time and this requires constant adaptation of receiving and transmission apparatus to the conditions of communication. To implement the modes of adaptation, continuous...
Modeling of the Brownian particle motion in the two-dimensional (2D) potential well by means of Langevin-type stochastic equations is performed. The behavior of the collective coordinate variances is in the focus. They are discussed for the cases of coupled and decoupled modes. The decision of some technical problems arising in such work is proposed.
Article deals with the problem of simulation modeling of robust control system for nonlinear plants with the input signal saturation, functioning under a priori uncertainty conditions and in the presence of several statement delays. With the help of computational experiments, the quality of the control system operation under various initial conditions of the controlled plant is illustrated.
The paper describes the direct torque control of the switched reluctance motor drives. A new engineering way for reducing electromagnetic torque ripples in the switched reluctance motor drives was shown. For this purpose, the constructed 3D model which was formed using the Kompas 3D program is presented in the paper. The results of the optimization and simulation using Matlab/Simulink are given.
Ensuring accurate testing of a UHF electronic package is the main requirement for a testing system. There are two problems: metrological certification as generator devices generating test pulses of desired amplitude and at a desired moment of time and the problem of measuring amplitude and time parameters of signals at the outputs of an electronic package. This paper observes the methods of measurement...
The article is devoted to the movement study of the unmanned aerial vehicle, type tricopter, with three controllable drives, all the propellers of which are rotary. The UAV is equipped with swept wings that allow it to provide aerodynamic stability. During take-off and landing the rotors work as lifting rotors, and while moving in the horizontal plane they work as the traction ones, shifting the plane...
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