The paper describes a multifactorial nonlinear regression model of revenue dynamics of the mining and metallurgical company Severstal, based on retrospective information for 2009-2021. Production volumes by type were used as independent variables: hot-rolled and cold-rolled sheet, galvanized sheet and sheet with other metal coating, rolled products, large diameter pipes, other pipe products and profiles. The criteria of multiple definition and Fisher, as well as the average absolute approximation error, were used as criteria for the adequacy of the model. A model competition was held to select the best regression dependence. As a result, a model is constructed containing inverse transformations of two independent variables in the right part.

Keywords: regression model, least squares method, adequacy criteria, mining and metallurgical company, revenue, model competition

In the work, based on the previously constructed multifactor dynamic regression model of water level in the Iya River (Eastern Siberia), the authors forecast this indicator for June 2023 in three options: pessimistic, optimistic and neutral (base). A comparison of the forecasting results with the actual value of the water level confirmed the high adequacy of the model and good prospects for its future successful use to solve a wide range of applied and practical problems.

Keywords: regression model, river water level, lag time, seasonal variable, forecast, adequacy, criteria

The paper presents a refined regression model of water level dynamics in the Siberian river Iya, which includes six natural factors on the right side (the number of days with precipitation in the Sayan Mountains, average day and night temperatures for the month, the amount of precipitation, snow depth, average atmospheric pressure for the month ) taking into account the delay, as well as a specially generated seasonal variable. The high adequacy of the model is indicated by the values ​​of the criteria of multiple determination, Fisher, and the average relative error of approximation. The constructed model can be effectively used to solve a wide range of forecasting problems.

Keywords: regression model, river water level, lag time, seasonal variable, forecast

Analyses for the current publishes show that the problem of forecast water overflowing is actual and often causing a lot health threaten and other dangerouses. This article offers computing, analysis and development the regression model of the level of Ia river. The final model correspont the real data with proper level. The final calculation means that this model could be used for real forecast for defend the people from water's overflow.

Keywords: model, simulation, river, water level, flood, emergency, forecast, statistics, monitoring, analysis, iya river, Irkutsk region

This article presents the results of computer simulation of electromechanical phase splitter working at idle mode based on a three-phase induction motor type HVA-55 with squirrel cage type rotor. Simulation made on the basis of previous studies of the auxiliary electric drives onboard of AC electric locomotives. These studies include: the development of a mathematical model of the three-phase induction electric machine that is suitable for describing the dynamics of electromagnetic, electromechanical and thermal processes under unbalance the power supply voltage, and also at not equal parameters at the each phase of machine; the development of computer models of various schemes of auxiliary electric drives of AC locomotives, having in its composition induction motor mathematical model. It has been demonstrated that the selected mathematical model of the induction machine can adequately describe the phase splitting process: the conversion of single-phase AC catenary voltage to three-phase voltage for auxiliary loads feeding.

Keywords: induction motor, mathematical model, electromechanical phase splitter, idle mode, AC electri locomotive, electric auxiliary drive, working capacity, start-up capacity, rotor, stator winding phase

Information about authors of issue №4 (2010)

Keywords: authors