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Apart from reliability evaluation, the methodology of network systems reliability assessment presented in the article enables the design of modernisation of such systems targeted mainly at ensuring their required reliability. In practice the methodology can be applied for various network systems, e.g. computer, power, gas, water distribution, telecommunications and transport networks. A reliability analysis of a transport network in urban public transport is presented. Calculations were performed for selected criteria of network availability which actually conditions the quality of transport services provided. The basic calculation tool used was the factoring algorithm that enabled the assessment of the impact of individual connections failure (in particular those caused by physical factors) on the reliability of the whole network. The feasibility of modernisation of the network analysed is discussed and the results are presented in diagrams.

The paper presents results of the analysis of the developed models for complex technical objects preventive maintenance scheduling. Models based on two different sets of assumptions were developed. The general problem solved was to determine the joint time of preventive renewal for a group of parts or subassemblies. The purpose of the first model (the model of scheduled preventive maintenance strategy) is to determine the profitability of constant application of a previously developed preventive maintenance schedule for a part undergoing post-failure renewal. The second model (the model of adaptive strategy of a system’s preventive maintenance) allows one to determine a new joint time of preventive renewal for a group of parts each time when one of them is undergoing a post-failure renewal. The initial preventive maintenance strategy for each part or subassembly was obtained using typical tools for maintenance planning (decision-random models based on dynamic programming and Bellman’s principle of optimality). Exemplary simulation calculations with the use of both models were made and their results presented as the total maintenance costs estimated for the renewal strategies developed. The object of the analysis were the chosen geometrical features of a rail vehicle wheel changing due to its wear during operation. Based on this kind of analysis, one can choose a better preventive maintenance model for a specific application area.

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The paper presents a concept of reliability estimation of the renewable technical systems consisting of the objects functioning in koon structures. The estimation is performed using computer simulation. Practical dependence between the failure of the entire system and the failures of the objects and elements from which the objects are made are taken into account as the result of the structural decomposition of the system conducted.Streszczenie: W artykule przedstawiono koncepcję szacowania niezawodności odnawialnych układów technicznych składających się z obiektów funkcjonujących w strukturach typu k z n, przy wykorzystaniu symulacji komputerowej. Występujące w praktyce zależności między uszkodzeniem układu a uszkodzeniami obiektów go tworzących i elementów, z których składają się obiekty, uwzględniono poprzez wykonaną dekompozycję strukturalną układu. Słowa kluczowe: niezawodność, struktury niezawodnościowe, symulacja komputerowa, dekompozycjaA concept of reliability assessment simulation model using systems structural... Koncepcja modelu symulacyjnego do szacowania niezawodności z zastosowaniem..