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Zaitsev D.,International Humanitarian University
CEUR Workshop Proceedings | Year: 2010

The universal inhibitor Petri net was constructed that executes an arbitrary given inhibitor Petri net. The inhibitor Petri net graph, its marking and the transitions firing sequence were encoded as 10 scalar nonnegative integer numbers and represented by corresponding places of universal net. The algorithm of inhibitor net executing that uses scalar variables only was constructed on its state equation and encoded by universal inhibitor Petri net. Subnets which implement arithmetic, comparison and copying operations were employed. Source

Zaitsev D.A.,International Humanitarian University
Automatic Control and Computer Sciences | Year: 2013

A technique of the computing grids verification using invariants of infinite Petri nets was presented. Models of square grid structures in the form of parametric Petri nets for such edge conditions as connection of edges and truncated devices were constructed. Infinite systems of linear algebraic equations were composed on parametric Petri nets for calculating p-invariants; their parametric solutions were obtained. P-invariant Petri nets are structurally conservative and bounded that together with liveness are the properties of ideal systems. Liveness investigation based on siphons and traps can be implemented using p-invariants of modified nets. © Allerton Press, Inc., 2013. Source

Goncharuk A.G.,International Humanitarian University
International Journal of Energy Sector Management | Year: 2013

Purpose: The paper aims to test the hypothesis about increasing the efficiency of gas distribution companies in the period of high gas prices on the example of Ukraine that is highly dependent on this energy source. Design/methodology/approach: The basic and super-efficiency models of data envelopment analysis (DEA), Malmquist total factor productivity index, three-factor production function and other tools are used to analyse the efficiency of gas distribution companies. Some factors are examined for their impact on efficiency. The results are based on the samples of 33 Ukrainian gas distribution companies. Findings: The author detects the decreasing returns to scale in the gas distribution sector, which means that Ukrainian gas companies get advantage reducing the volume of gas supply. Rise in prices for imported gas is reflected positively not only on the income of the exporting Russian supplier Gazprom, but also on the profitability of Ukrainian gas distribution companies. The losses associated with the policy decisions regarding a pricing of imported natural gas moved on the consumers of natural gas - the manufacturing sector of the economy and the population. Reallocation of net profit from the key export sectors of Ukraine in the gas sector is mainly caused by the fault of the state regulatory body. Research limitations/implications: The research is limited by single industry and by relatively short data set. The former is explained by requirement of technology (product, service) homogeneity when using DEA tools. The latter is connected with specificity of the industry and generally little numbers of firms in it. Practical implications: The results of researching contain the data and recommendations to companies' management and a state regulatory body to correct and optimize their decisions to make gas distribution system and economy more effective. These results can be practicable for companies' management, present and potential investors and proprietors, regulative public authority. It is possible to use the results of this research to make study for the other industries. Originality/value: This is the first paper that studies the impact of high natural gas prices on the economy and gas distribution system of Ukraine. © Emerald Group Publishing Limited. Source

Goncharuk A.G.,International Humanitarian University
International Journal of Technology, Policy and Management | Year: 2016

The purpose of this study is to define the key sources of investments for steel and chemical companies under the pressure of high gas prices, and the government's capability to activate their investment activity. The author used the traditional methods of structural, dynamic and statistical regression analysis to investigate the sources of investments and to identify the establishing of quantitative relationships between natural gas prices and the company's indicators. When natural gas prices grow an investment activity of the steel and chemical companies is declining. Under the tough pressure of gas prices, these companies use only two sources of investments: long-term loans and depreciation funds. If the company's unprofitability is long-lasting, depreciation is not enough even to cover losses, thus, the company has to accumulate loan debts or to become bankrupt. To ensure break-even operations of such enterprises, the government should keep price for natural gas below certain thresholds. Using the developed models, author determined critical levels of natural gas prices for metallurgical and chemical industries. Copyright © 2016 Inderscience Enterprises Ltd. Source

Zaitsev D.A.,International Humanitarian University
IEEE Transactions on Systems, Man, and Cybernetics: Systems | Year: 2016

We show that Sleptsov place-transition nets (that allow transition firing in multiple instances at a step) run fast by implementing multiplication and division operations in polynomial time. In comparison, Petri nets (PNs) implement the mentioned operations in exponential time. Moreover, PNs are obtained as a special case of Sleptsov nets (SNs) using loops with places having unit marking attached to each transition. In addition, we develop basics of an SN programming technology including basic operations and program composition rules. We provide examples of programs written in SN language for encryption/decryption with the RSA algorithm, calculation of fuzzy logic functions, and parallel calculation of the solutions to Laplace equations. SN computers promise hyper-performance because of a concurrent programming style consisting of a concise graphical language and small granulation of parallel processes on the level of separate events. © 2015 IEEE. Source

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