Browsing by Author "Safranov, Timur"

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    Advanced modeling and forecasting of pollutant concentrations temporal dynamics in the atmosphere of an industrial city (gdansk region)
    (Publishing House of Lviv Polytechnic National University, 2016) Glushkov, Alexander; Safranov, Timur; Khetselius, Olga; Prepelitsa, Georgy; Bunyakova, Yuliya; Bykowszczenko, Nataliya
    In the paper we present the results of an advanced investigation of dynamics of variations of the atmospheric pollutants (sulphur dioxide) concentrations in the air basins of Polish industrial cities (Gdansk region) by using the improved non-linear prediction and chaos theory methods. Chaotic behavior of the sulphurous anhydride concentration time series at two sites in the city of Gdansk has been computed. As usually, to reconstruct the corresponding chaotic attractor, it is necessary to determine time delay and embedding dimension. The former is determined by the methods of autocorrelation function and average mutual information, and the latter is calculated by means of the correlation dimension method and algorithm of false nearest neighbours. Further, the Lyapunov exponents’ spectrum, the Kaplan-Yorke dimension and the Kolmogorov entropy and other invariants are calculated. An existence of a low-D chaos in the cited system is confirmed and using polynominal algorithm with neural networks block allows making an improved short-term forecast of the atmospheric pollutant fluctuations dynamics.
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    Analysis and forecast of the environmental radioactivity dynamics based on the methods of chaos theory: general conceptions
    (Publishing House of Lviv Polytechnic National University, 2016) Glushkov, Alexander; Safranov, Timur; Khetselius, Olga; Ignatenko, Anna; Buyadzhi, Vasily; Svinarenko, Andrey
    For the first time, we present a completely new technique of analysis, processing and forecasting of any time series of the environmental radioactivity dynamics, which schematically is as follows: a) general qualitative analysis of a dynamical problem, typical environmental radioactivity dynamics (including a qualitative analysis from the viewpoint of ordinary differential equations, the “Arnold-analysis”); b) checking for the presence of chaotic (stochastic) features and regimes (the Gottwald-Melbourne’s test; the correlation dimension method); c) reducing the phase space (the choice of time delay, the definition of the embedding space by the correlation dimension methods and false nearest neighbours algorithms); d) determination of the dynamic invariants of a chaotic system (computation of the global Lyapunov dimension la; determination of the Kaplan-Yorke dimension dL and average limits of predictability Prmax on the basis of the advanced algorithms; e) a nonlinear prediction (forecasting) of any dynamical system evolution. The last block really includes new (in the theory of environmental radioactivity dynamics and environmental protection) methods and algorithms of nonlinear prediction such as methods of predicted trajectories, stochastic propagators and neural networks modeling, renormanalysis with blocks of polynomial approximations, wavelet-expansions etc.