The problem of choosing a project for a developing engineering network is considered. A mathematical model of a developing engineering network, which even at the design stage allows us to take into account the possibility of expanding or reconstructing the system in case new customers are added to the target product, which is a two-criteria block programming problem with separable criterion functions. In the proposed mathematical model, the first criterion reflects the need to minimize financial costs construction and operation of the network, in order to ensure portability of the target product delivered at the time of designing. The second criterion expresses the requirement of minimizing financial costs for the future development of the system in the future from the achieved level, provided that the vector of the system’s development is known before the engineering network design starts. Taking into account the criteria preference vector, which allows you to take into account the inequality of both cost criteria in the constructed mathematical model and makes it possible comparing criteria of different orders makes it possible to replace the two-criterion optimization problem of choosing a project of a developing engineering network with a single-criterion mathematical programming problem without changing the set of solutions to the problem. The formulated properties of the set of effective vectors of criterion values, that arise when solving a single-criterion problem of optimizing the choice of a choice of a design option for an engineering network by varying all possible values of the criteria preference vector, it gives the most complete information for making a design decision.

ДИФУЗІЙНІ ПРОЦЕСИ З НАКОПИЧУВАЛЬНИМИ ХАРАКТЕРИСТИКАМИ ПРИ ЕКСПЛУАТАЦІЇ БУДІВЕЛЬ Г.В. Гетун 1 , канд. техн. наук, професор, професор кафедри архітектурних конструкцій Ю.П. Буценко 2 , канд. фіз.-мат. наук, доцент, доцент кафедри математичного аналізу та теорії ймовірності О.І. Баліна 1 , канд. техн. наук, доцент, доцент кафедри інформаційних технологій проектування та прикладної математики І.С. Безклубенко 1 , канд. техн. наук, доцент, доцент кафедри інформаційних технологій проектування та прикладної математики А.В. Соломін 2 , канд. фіз.-мат. наук, доцент, доцент кафедри біобезпеки і здоров'я людини 1 Київський національний університет будівництва і архітектури, Київ

The solution of technical problems to ensure the working capacity is largely determined by the effectiveness of theoretical and applied developments in an area of estimation and prediction of their reliability indicators. An effective approach to the analysis of failures and the development of operability and parametric reliability models provides an opportunity to obtain more adequate models of reliability of hydraulic drives of machines, as they more fully take into account the specifics of the structure and functioning of the hydro drive elements of construction machines, their relationships and features of the formation of parameters failures. And this will allow to get more real and accurate results of estimation of reliability indicators of hydraulic drives of both construction and other hydraulic machines. They do not exhaust all possible variants of models that can take place when analyzing the reliability of hydraulic drives of machines, but at the same time they to a certain extent extend and refine the set of known reliability models. Specific in terms of formation of parametrical failures are such consistently connected in terms of the layout of hydraulic elements, as working sections of hydraulic distributors and hydraulic cylinders, which are part of the subsystems of GPs and form the so-called functional areas (FA). Reaching the FA limit is a compatible result of the combined random process of evolution of the volumetric efficiency JCUA  these elements, and the technical condition of the FA is estimated to be generalized by the JCUA, which equals the product of the JCUA of consecutively connected elements: . In this case, the probability of maintaining the capacity of the FA will be: . The processing of diagnostic information and the study of the reliability of GPs in real conditions of their operation showed that the distribution of JCUD hydraulic elements with a sufficient degree of consistency can be described under several theoretical laws. It is considered when the JCUA sections of the hydraulic distributor and hydraulic cylinder are distributed by gamma distribution and exponential distribution. The use of the general methodological approach to the analysis of failures and the construction of models of operability and parametric reliability provides an opportunity to obtain more adequate models of reliability of hydraulic drives of machines, as they more fully take into account the specifics of the structure and functioning of the hydraulic drive elements, They don't exhaust all possible models that can take place when analyzing the reliability of hydraulic drives, but at the same time they are to some extent expanding and refining the range of already known models of reliability.

The emergence of new types of structures and construction technologies related to them became the impetus for the search for new forms of buildings and structures and the development of a new understanding of space. Technical and economic calculations show that the area of coverings in buildings with large hall rooms, as a rule, exceeds the total area of other enclosing structures, and therefore the cost of coverings, taking into account installation work, is of predominant importance in construction estimates. Spatial forms of coverings of hall rooms significantly affect the architectural expressiveness of buildings, and therefore the issue of choosing forms, materials and rational constructive solutions of coverings is extremely relevant. The most important components of the covering systems of buildings and structures are supporting structures, which have unlimited possibilities of interpretation of forms and materials, can be hidden or open and turn into architectural elements. It is obvious that in the process of designing the coverings of buildings and structures, it is necessary to consider and analyze various options for their constructive solutions. The article analyzes the types of arches, their classification, the conditions of use as load-bearing structures of building coatings, as well as some problems of their static operation, which are related to the choice of form and conditions of their support and division into structural elements. The authors considered the problems of calculating and designing arches, choosing rational forms of arches that ensure the prevention of loss of their stability from the bending plane and a high aesthetic level. The main principles and methods of construction and static calculation of arches are presented.

The introduction of hardware redundancy in most cases is used as a method of increasing a reliability of non-repairable (non-recoverable) equipment. In this case, not only the improvement of such an indicator as the probability of failure-free operation can be achieved, but an increase in MTBF as well. The article shows that in the case of introducing redundancy for the restored equipment, additional opportunities arise for organizing self-diagnosis (self-monitoring) of the technical condition of the equipment. On the example of the structure of the popular NonStop solution derived by the Tandem company, specific proposals for the development of real-time signals for indicating the current technical state of the structure in the event of pre-emergency or emergency situations are considered. It is shown, that aforementioned possibilities are practically absent in the majority structures in the case of triple redundancy and significantly improve upon the transition to structures of higher redundancy. Another important and useful feature of such structures is the ability to adapt the signal generation algorithm when a part of the equipment fails in the structure. In the case of "Tandem"-type structure after the failure of one of the elements, the implementation of the adaptation algorithm leads to a structure with triple redundancy of the majority type, which has significant advantages over double-redundant. The analysis of "Tandem"-type structures for various starting positions was carried out. Analytical expressions are obtained for the average transition times from the "Tandem" scheme to the triple redundancy scheme (hereinafter, to the double redundancy scheme with subsequent absence of redundancy), the average reverse transition times in the presence of recovery possibilities, and, based on them, coefficients of readiness are calculated.