modeling

Mathematical modeling of non-stationary gas flow modes along a linear section of a gas transmission system

Article demonstrates the applicability of modeling non-stationary non-isothermal gas flow along a linear section of a gas transmission system by means of using various numerically simulated models and sophisticated numerical techniques.  There are described several models of non-stationary non-isothermal regimes of gas flow along the pipeline section.  They are included in the considered general model and their comparative analysis is carried out by the virtue of numerical simulation.  The finite difference algorithm is used to solve the simultaneous equations of the numerically simulated m

Providing cyber resilience in software-defined networks by secure routing means

This paper is devoted to solving the technical task of providing cyber resilience utilizing secure routing means in Software-Defined Networks (SDN). The work analyzes the SDN architecture and
its main components, the concept of cyber resilience and its means, as well as security issues in SDN. Particular attention is paid to the use of secure routing in software-defined networks.
Numerical research of the model of secure multipath routing of fragmented confidential messages in the SDN data plane was conducted. The calculation of the message compromise probability for

Modeling of production processes with regeneration for ensuring enterprise competitiveness

The article presents the research and rationale of theoretical issues and applied decisions regarding the influence of enterprises and the mechanism of managing production processes with regeneration (renovation) on the competitiveness.  Mathematical tools were developed and methods for calculating basic economic indicators were suggested, namely, the starting factors and direct regulatory costs for materials; the economic and mathematical model of production processes with regeneration was designed, which allows comparing the output of production with the cost of its manufacturing and the

Position Controller Design and Implementation of Ball and Beam System with SMC and PD Control Methods

Today, several methods are proposed and tested for controlling many nonlinear and unstable systems. This study employed the sliding mode control (SMC) and proportional-derivative (PD), which are used to control the position and modeling of ball and beam system that is a fundamental system used to test the control methods. Such systems are nonlinear and unstable due to their nature. Therefore, these systems are affected by external disturbances and this leads to a decrease in the control quality.

MODELING THE IMPACT OF GCI COMPONENTS ON UKRAINE COMPETITIVENESS

Global competition is growing not only on a products/firms level, but also among countries. There are many approaches to interpretation of a concept of the “country competitiveness”, which in particular means “the state of the country in the global market due to the international division of labor, national conditions and factors of production and its ability to compete effectively in world markets”.

EMERGENCY CONDITION OF LOGGIES IN BUILDINGS WITH SUPPORTING BRICK WALLS

This article is devoted to the problems of the existing residential buildings of 70-80 years of construction of the last century, which have been in operation for about 50 years and are subject to immediate technical inspection. The most important factor for the safe operation of such buildings is the quality of construction, as in this period the construction was performed with many shortcomings that are manifested today. The article describes the problem of joints of loggias with the building in the design and construction of multi-storey buildings with load-bearing brick walls.

Modeling of partially regular microreliefs formed on the end faces of rotation bodies by a vibration method

The scheme of formation of a set of variants of grooves of partially regular microreliefs formed on the end faces of rotation bodies by a vibration method has been developed, and the conditions of their existence have been determined. Using a block approach, mathematical models of partially regular microreliefs have been constructed, which described a set of their variants, taking into account such characteristics as the shape of axial lines of continuous regular microroughness, type, and location of axial symmetry lines of grooves, and groove shape.

Modeling of “combined cutter - cone” connection in tricone drill bits

A theoretical analysis of the stiffness of the “cutter-cone” connection was performed. In the article the character and magnitude of the tension at the contact of "cutter-cone" are investigated. An analysis of the surface of the openings for carbide inserts revealed traces of plastic deformation and fretting wear.

Influence of transportation object position in car body on its vibrational loading

Dynamic model for research of object transportation location influence on its vibrating loading by moving through a number of single obstacles, road with random microprofile and rough road is offered. Differential equations and methods of their integration in MATLAB Simulink software product are presented. The values of frequencies and amplitudes of vertical oscillations, vibration acceleration of the transportation object at different locations in the vehicle body were obtained.

Parallel Operation of Transformers Within the Power Supply System of a Mine

Connecting transformers in parallel requires a few of important requirements. During operation of the industrial supply power systems, there are sometimes situations when it becomes desirable to operate of parallel transformers, the characteristics of which do not quite correspond to such a procedure. When transformers are connected in parallel, any difference between their parameters causes the load to be redistributed between them compared to the previous operating mode they had been operating in isolation.