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35. Dynamics of sunspot series on time scales from days to years : correlation of sunspot births, variable lifetimes, and evolution of the high-frequency spectral componentAlexander Shapoval, Jean-Louis Le Mouël, M. Shnirman, Vincent Courtillot, 2017, original scientific article Keywords: sunspots series, average lifetime, average birthrate, data analysis Published in RUNG: 30.03.2021; Views: 2470; Downloads: 105 Link to full text This document has many files! More... |
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39. Industry equilibrium and welfare in monopolistic competition under uncertaintyAlexander Shapoval, V. M. Goncharenko, 2020, original scientific article Abstract: This paper offers a new theory that describes the influence of uncertainty on economic fundamentals. This theory posits that uncertainty can improve social welfare. We argue that in an economy, where spending of the customers for the differentiated good correlates with larger substitutability of its varieties, the equilibrium output decreases and the prices increase when uncertainty appears. Alternatively, if such spending and substitutability anti-correlate, the predictions for the price and output changes are reversed. The arguments are based on general equilibrium modeling with the monopolistic competition of firms which produce varieties of the differentiated good under limited information regarding the consumer demand. The impact of uncertainty on the equilibrium is assessed by using the relationship between the weighted elasticity of substitution between varieties, the elasticity of the consumer utility, and the income share spent on the differentiated good. Keywords: monopolistic competition, uncertain demand, general utility, consumer welfare Published in RUNG: 22.03.2021; Views: 2526; Downloads: 0 This document has many files! More... |
40. Reconstruction of the coupling between solar proxies : when approaches based on Kuramoto and Van der Pol models agree with each otherAnton Savostianov, Alexander Shapoval, M. Shnirman, 2020, original scientific article Abstract: The objective of this paper is to establish that algorithms, which reconstruct the coupling between solar proxies based on the properties of the Kuramoto equations, and algorithms, based on the van der Pol equations, might produce similar estimates. To this end, the inverse problem is formulated as follows: reconstruct the coupling based on the solutions of the corresponding equations. For either system of the equations we construct an algorithm solving the inverse problem and establish that there exists a range of moderate values of the correlation such that the algorithms produce practically identical coupling within the established range. The lower boundary of this range is dependent on the half-difference of the oscillators’ frequencies. Then, we apply the two reconstruction algorithms to solar index ISSN and the geomagnetic index aa, which are proxies to the toroidal and poloidal magnetic fields of the Sun respectively. Their correlation belongs within the range that yields the proximity of the coupling reconstructed with all solar cycles from 11 till 23 except 20 and, possibly, 21. Our finding relate the reconstruction of characteristics of solar activity inferred by Blanter et al [Sol. Phys. 2014, 289, 4309; Sol. Phys. 2016, 291, 1003] from the Kuramoto model to the state of the art solar dynamo theory based on the magnetohydrodynamic equations. Keywords: coupled oscillators, synchronization, solar activity Published in RUNG: 22.03.2021; Views: 2486; Downloads: 0 This document has many files! More... |