https://elib.bsu.by:443/handle/123456789/254275 NPCS Vol.22, no.2 (2019), pp. 104-207 Mon, 20 Apr 2026 13:32:51 GMT 2026-04-20T13:32:51Z https://elib.bsu.by:443/handle/123456789/254345 Заглавие документа: On a Modified Vakhnenko–Parkes Equation Авторы: Sakovich, S. Yu. Аннотация: We show that the modified Vakhnenko–Parkes equation, introduced recently by Wazwaz, is an avatar of the sine-Gordon equation. Tue, 01 Jan 2019 00:00:00 GMT https://elib.bsu.by:443/handle/123456789/254345 2019-01-01T00:00:00Z https://elib.bsu.by:443/handle/123456789/254343 Заглавие документа: Multifractal Security Analysis of Cyberphysical Systems Авторы: Zegzhda, D.; Lavrova, D.; Poltavtseva, M. Аннотация: In this paper authors propose to use multifractal analysis and Kalman filter for security analysis of cyberphysical systems (CPS). First stage of the proposed approach is data reduction caused by time series processing. The second stage is anomaly detection and the third stage is attack prediction. For anomaly detection it has been proposed to use multifractal analysis and time series prediction. Most real processes, as scientific researches are shown, have multifractal nature. Multifractal analysis and Legendre spectrum characteristics calculation allow to detect violation of multifractal properties caused by cyberattack. Kalman filter is used for cyberattack detection at early stage, because it performs system state prediction with high accuracy. The effectiveness of the proposed approach is confirmed by experimental results. Tue, 01 Jan 2019 00:00:00 GMT https://elib.bsu.by:443/handle/123456789/254343 2019-01-01T00:00:00Z https://elib.bsu.by:443/handle/123456789/254342 Заглавие документа: Non-rough Relaxation Solutions of a System with Delay and Sign-Changing Nonlinearity Авторы: Kashchenko, A. Аннотация: In this paper we study nonlocal dynamics of a system of two coupled delay differential equations with a sign-changing compactly supported nonlinearity. The main assumptions in the problem are that nonlinearity is multiplied by a large parameter and a coupling coefficient is sufficiently small. Using asymptotic methods we investigate the existence of relaxation periodic solutions of a given system. We choose a special set in the phase space of the initial system. Then we calculate asymptotics of all solutions of the considered system with initial conditions from a chosen set. By this asymptotics we build a special mapping. Cycles of this mapping correspond to periodic asymptotic (by the discrepancy) solutions of the initial system. Constructed mapping has a two-parameter families of non-rough cycles. Thus, the initial system has two-parameter families of non-rough inhomogeneous relaxation periodic asymptotic (by the discrepancy) solutions. Tue, 01 Jan 2019 00:00:00 GMT https://elib.bsu.by:443/handle/123456789/254342 2019-01-01T00:00:00Z https://elib.bsu.by:443/handle/123456789/254341 Заглавие документа: Cavity Dumping by the Second Harmonic Generation in the Mode-Locked Nd:YAG Laser Авторы: Navitskaya, R. I.; Stashkevitch, I. V. Аннотация: A method of cavity dumping by the second harmonic generation that allows one to obtain short and intensive pulses of laser radiation in the visible band is considered. It is based on intracavity second harmonic generation in lasers with highly-reflective mirrors for the fundamental frequency radiation. The second harmonic generation is obtained with the type II crystal and is controlled with the use of a polarizer and a voltage-activated electrooptic crystal inside the cavity. The method enables one to retain the laser beam quality and propagation direction after transformation into the second harmonic. The method may be implemented in solid-state laser systems operating in different modes: mode-locking, Q-switching, and CW. Most effective second harmonic generation is realized in the mode-locked lasers with ps-duration output pulses and peak intensity up to GW/cm2. We propose a theoretical model and analysis of the cavity dumping by the second harmonic generation in the mode-locked solid-state lasers that is based on the Herman A. Haus approach. The dynamics of the pulse formation in the mode-locked regime is investigated; the parameters of the output second harmonic pulses and their dependence on the main system characteristics are determined. It is shown that the output pulse peak intensity, length, and energy per unit area depend on the pump power and loss coefficient in the cavity: to obtain pulses with higher intensity, energy and smaller length, the pump power should be increased and losses decreased to the minimal value possible. One can obtain the output pulses with the energies per unit area coming to several mJ/cm2. The output pulse parameters may also depend on the dumping period. The cavity dumping repetition rate may be as high as MHz. Tue, 01 Jan 2019 00:00:00 GMT https://elib.bsu.by:443/handle/123456789/254341 2019-01-01T00:00:00Z