Forecasting the mobility parameters of the inhabitants of suburban areas

Potential mobility that meets the requirements of population displacement is determined following the biological and social needs, socio-economic characteristics, production necessity, and cultural needs. Because of the multifactor character and complexity of relationships, it is impossible to determine the potential mobility by a calculation method. The feasibility of different target movements, depending on their distance, is regarded by rural populations differently.

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.

Improved calculation and strength of thermowells during operation

Accurate evaluation of possible safe operation of thermowells essentially depends on the accuracy of the maximum stresses in them during operation. These stresses are generally determined from simple engineering formulas for bulk of canonical shape, mostly cylindrical shells or beams for the relevant boundary conditions. Thus the general solution is obtained step by step. First the tangential stresses are obtained from relations for cylinder subjected to external pressure.

Моделі якості послуг телекомунікаційних мереж

The quality of service models of telecommunication networks was considered. The features of providing of quality of service in the telephone and computer networks was explored. On the basis of this research it sets, that the metropolitan telephone networks are characterized by a higher accuracy, dependability and security by comparison to the computer local area networks. Substantial advantage of computer local area networks above the metropolitan telephone networks is providing a higher speed of the user information transfer, although defect there is an instability of this speed.

Огляд і аналіз моделей надійності програмного забезпечення.

Оглянуто та проаналізовано моделі надійності програмного забезпечення. Наведено класифікацію моделей за різними критеріями. Особливу увагу зосереджено на моделях надійності, що враховують явище недосконалого відлагодження, зокрема на моделях на основі неоднорідного пуассонового процесу з використанням функцій розподілу зусиль тестування. Розглянуто основні функції розподілу зусиль тестування та проаналізовано їх інтеграцію з моделями надійності програмного забезпечення.

Reliability Model of Fault-tolerant System Based on the Majority Structure {3 of 5} With Combined Structural Redundancy and Maintenance

Designing of radio-electronic systems of responsible purpose with hardware-software implementation involves the mandatory provision of their property of fault-tolerance. The property of fault-tolerance are provided by the use of fault-tolerant systems. For these fault- tolerant systems at the stage of system engineering design it is necessary to solve the problem of reliability structural-parametric synthesis. A designer must have a high degree of adequacy of reliability models of fault-tolerant systems with different configurations to solve such a task.

Extending the features of software for reliability analysis of fault-tolerant systems

The developed software ASNA-2, which is an improved version of the software ASNA-1, is based on the technology of automated estimation of reliability indexes of fault-tolerant systems. This software is designed for automated evaluation of the reliability indexes of fault-tolerant hardware – software systems. This paper describes a software ASNA-2 with the peculiarities of procedures of  reliability analysis of fault-tolerant systems.

Analytical reliability model of a redundant repairable system with limited number of restorations

Modern complex mission-critical systems are built as fault-tolerant systems, i.e. having the ability to function while some of their separate elements have a fault. The complexity of such fault-tolerant systems makes their reliability models quite big and complex. Therefore, such requirements for building models, as the high level of credibility and the appropriate level of formalization, are imposed on these models, which allows to implement the automation to their creating and analysis of reliability and, therefore, using modern computer tools.

Estimation of operation reliability of control electronic systems with the use of maximum product problem

In the article there are presented the results of analytical research on the operation reliability of a complex engineering system using the example of a control electronic system. Functioning of such a system is suggested to be considered with the use of a maximum product problem. At the same time an adequate balance between its reliability and efficiency is chosen as a criterion for the estimation of its reliable and efficient functioning.

Research on efficiency of telephone networks with different structures

With the development of communication networks, their structures have also evolved and improved. Today the prospective development and construction of telephone networks of all levels of hierarchy calls for insight into their structures. The aim of this paper is determination and analysis of the efficiency of the most widespread structures of public telephone networks according to specific criteria for effectiveness.