GOLD PRICESFORECASTING USING TRIPLE EXPONENTIAL METHOD

Governments, organizations, and citizens have taken an interest in gold price fluctuations. Gold price forecasting that is accurate may effectively capture price shift tendencies and reduce the effects of gold market volatility. However, due to the multi-factor and nonlinear nature of the gold market. The triple exponential smoothing strategy is used in this study to predict the rise in a value over time since it can replicate trends and seasonal patterns. according to the gold price swings pattern and seasonal components at the same time To calculate system accuracy, the Mean Absolute Percentage Error is employed (MAPE). With alpha 0.15 and beta 0.85 as parameter values, the triple exponential smoothing (TES) approach achieves an accuracy rate of 86.93 percent and a MAPE of 12.49 percent in this study.

Model of pulsating current traction motor taking into consideration magnetic losses in steel

The aim of the work is to develop a mathematical model of the traction motor of the pulsating current of an electric locomotive taking into account the magnetic losses in the motor steel to determine the starting parameters depending on the voltage of the armature winding. Methodology. Mathematical modeling of electromagnetic processes in a traction motor of pulsating current is applied taking into account the nonlinear nature of the armature inductance, the inductance of the excitation winding and the nonlinear nature of the universal magnetic characteristic. The magnetic losses in the steel of the traction motor were taken into account by establishing the dependence of these losses on the frequency of reversal, the magnetic flux in the magnetic circuit of the motor and the geometric dimensions of the motor. Results. The mathematical model of calculation of starting parameters of the traction engine of the pulsating current of the traction drive of the electric locomotive of alternating current taking into account the equation of instantaneous value of losses in engine steel is developed. The dynamic characteristics of the traction motor with pulsating current are obtained. It allows to investigate starting parameters of the traction engine on the basis of the received mathematical model and to design elements of the traction drive of the electric locomotive according to the specification, to choose optimum design parameters. Originality. For the first time a comprehensive study of the pulsating current traction motor was carried out taking into account the nonlinear nature of the armature inductance, excitation winding inductance and nonlinear nature of the universal magnetic characteristic and taking into account the magnetic losses in the motor steel. Practical significance. The model of the traction motor of pulsating current taking into account losses in steel of the engine on the basis of the carried-out calculation is developed. Experimental studies have confirmed the adequacy of the model, which allows to apply the obtained model to develop a mathematical model of an AC electric locomotive to study the electrodynamic processes in it at different modes of operation of the electric locomotive.

Testing the magnetoactive elastomer sample for compression with the test machine

A sample of a magnetoactive silicone composite with ferromagnetic fillers is examined on a testing machine. The dependences of the change in the values of the moduli of longitudinal elasticity on deformation are plotted for various modes of compression of the sample. The characteristics of the linear and nonlinear dynamics of changes in the moduli of longitudinal elasticity are given as a function of the magnitudes of the deformations of the material during compression. Within the limits of deformation of the sample, which is 24% of its height, the moduli of longitudinal elasticity are linear. The nonlinear nature of the change in the compression modulus occurs when the sample is deformed over 40%. When the compression ratio of the sample was up to 72%, the compression modulus increased by a factor of 9 without the action of a magnetic field and by a factor of 22 under the action of a magnetic field. The influence of the magnetic field on the growth of the compression moduli with the increase in the compression force ranges is shown. The property of the material to self-healing (“shape memory”) was established after testing in the mode of maximum compression of ultimate loads.

Variation Trends of Fractal Dimension in Epileptic EEG Signals

Epileptic diseases take EEG as an important basis for clinical judgment, and fractal algorithms were often used to analyze electroencephalography (EEG) signals. However, the variation trends of fractal dimension (D) were opposite in the literature, i.e., both D decreasing and increasing were reported in previous studies during seizure status relative to the normal status, undermining the feasibility of fractal algorithms for EEG analysis to detect epileptic seizures. In this study, two algorithms with high accuracy in the D calculation, Higuchi and roughness scaling extraction (RSE), were used to study D variation of EEG signals with seizures. It was found that the denoising operation had an important influence on D variation trend. Moreover, the D variation obtained by RSE algorithm was larger than that by Higuchi algorithm, because the non-fractal nature of EEG signals during normal status could be detected and quantified by RSE algorithm. The above findings in this study could be promising to make more understandings of the nonlinear nature and scaling behaviors of EEG signals.

Shadow of a noncommutative-inspired Einstein–Euler–Heisenberg black hole

We consider the orbits of test particles moving in the gravitational field of a noncommutative-inspired Einstein–Euler–Heisenberg black hole. Using the geometric metric, we determine the circular orbits followed by massless particles, comparing them with the circular photon orbits coming from the Plebanski pseudo-metric that takes into account the nonlinear nature of the Euler–Heisenberg electrodynamics. Using the impact parameter of the photon orbits, we define the shadow of the noncommutative-inspired black hole and discuss the constraints on the model by comparing its shadow with the prediction from General Relativity.

The Approach for Studying Variability of Sea Wave Spectra in a Wide Range of Wavelengths from High-Resolution Satellite Optical Imagery

The development and validation of a method for remote measurement of the spectra of sea waves, which significantly expands the capabilities to study surface waves in large water areas in a wide range of wavelengths, is described. The applied approach is based on the use of retrieving operators, which are constructed by the method of numerical simulation, taking into account the nonlinear nature of brightness field modulation by the slopes of the sea surface. Retrieving operators have a set of parameters that are adapted to the real conditions of aerospace imaging. To assess the adequacy of the retrieving of wave spectra recorded from satellite images, they are compared with the spectra obtained by ground-based means under controlled conditions. The studies have shown the adequacy of remote measurement of the spectra of slopes and elevations of sea waves with wavelengths in the range 0.1–1 m. The possibility of using the developed method for studying the variability of sea waves in the coastal zone under conditions of limited fetch, including in the presence of anthropogenic disturbances, is shown.

Nonlinear models of the Phillips curve

The recent flattening of the Phillips curve has stimulated new empirical research and theoretical discussions regarding the nonlinear nature of the changes in the parameters. The objective of the present paper is twofold: to detect the relevant type of the implied nonlinearity and look for some general model capable of generating a Phillips curve mimicking the empirical one. We find evidence of a convex US price Phillips curve, from 1961 q1 to 2019 q4, assessed both by piecewise and threshold models. The result presents some degree of novelty regarding the role of supply shocks and model-specific convexities; in addition, it supports the use of a regime-switching macro system. The latter accomplishes three tasks. It can generate a Phillips curve resembling its empirical counterparts; it creates a medium-run endogenous cycle where unemployment is not a NAIRU; finally, it opens new perspectives on economic policy issues.

MODEL OF INTERACTIONS AND PHASE STATES IN THE DISTRIBUTION OF THE FREQUENCY RESOURCE IN THE GROUPING OF RADIO ELECTRONIC MEANS OF A 5G MOBILE COMMUNICATION NETWORK

Subject: interaction models and phase states in the distribution of the frequency resource in the grouping of radio electronic means of the 5G mobile communication network. Purpose: development of a dynamic model of multiple interactions of n-elements of a complex 5G mobile communication system, which takes into account the nature of inter-element connections and phase states in the group use of the frequency resource. Tasks: on the basis of a complex model of an n-element system with multiple interactions, to develop a mathematical model for describing the electromagnetic environment of a grouping of radio electronic means in a state space with a group use of a frequency resource; to analyze the phase states of interaction of the elements of the grouping system of radio-electronic means of the mobile communication system in which they can function without deteriorating the quality indicators, which reflect the total level of the group influence of the emitting elements on the receiving devices, under conditions of optimal distribution of the frequency resource. Methods: mathematical method of the state space of the system, which describes the nonlinear nature and phase states of the system, taking into account the intensity of the interaction of its elements. Results: A mathematical model of the electromagnetic environment of a grouping of radio-electronic devices based on the Volterra model has been developed, which characterizes their nonlinear nature of interactions in the group use of the frequency resource. A recurrent expression is obtained for modeling the assessment of the aggregate nature of electromagnetic interactions in a group of radio-electronic means. Modeling of the dynamics of interaction and phase states of the grouping of radioelectronic devices in the group use of the frequency resource has been carried out. Conclusions: It is shown that using a model that simulates the dynamics of interactions of a group of radioelectronic, it is possible to analyze its state in the future. This model makes it possible to analyze the grouping of radio-electronic means with different, specific parameters of individual types of radio electronic devices, the nature and intensity of their interaction in the grouping with the current distribution of resources.

Nonlinear distortion compensation method for locating maneuvering targets

В работе предложен метод решения проблемы в области обработки радиолокационных сигналов с линейной частотной модуляцией (ЛЧМ), обеспечивающий компенсацию нелинейных изменений радиальной скорости локационного объекта (ЛО) при его маневрировании. Метод основан на компенсации искажений радиолокационных сигналов, отраженных от ЛО, вызванных нелинейным характером изменения радиальной скорости при маневрировании в предположении линейного изменения скорости за время когерентного накопления (КН). Приведены результаты моделирования обработки сигналов с реализованным методом компенсации. A method for solving the problem in the field of radar signal processing with linear frequency modulation is proposed. The method provides compensation for nonlinear changes in the radial velocity of a aircraft during its maneuvering. The method is based on the compensation of reflected pulses distortions caused by the nonlinear nature of the change in radial velocity of a aircraft during its maneuvering. It is assumed that during the time of doppler process the radial velocity changes linearly. The results of signal processing simulation with the implemented method are presented.