Qualitative Importance Measures of Systems Components – A New Approach and Its Applications

Abstract

The paper presents an improved methodology of analysing the qualitative importance of components in the functional and reliability structures of the system. We present basic importance measures, i.e. the Birnbaum’s structural measure, the order of the smallest minimal cut-set, the repetition count of an i-th event in the Fault Tree and the streams measure. A subsystem of circulation pumps and fuel heaters in the main engine fuel supply system of a container vessel illustrates the qualitative importance analysis. We constructed a functional model and a Fault Tree which we analysed using qualitative measures. Additionally, we compared the calculated measures and introduced corrected measures as a tool for improving the analysis. We proposed scaled measures and a common measure taking into account the location of the component in the reliability and functional structures. Finally, we proposed an area where the measures could be applied.

Modelling and Resolution of Dynamic Reliability Problems by the Coupling of Simulink and the Stochastic Hybrid Fault Tree Object Oriented (SHyFTOO) Library

“…Other suggested improvements can be found in the literature, such as [40], which integrated prognostic estimations into dependability assessment to avoid using average failure rate data, which leads to outdated system-level dependability estimation, and proposed a new framework, which results in more realistic and accurate dependability predictions. A methodology for combining the Fuzzy logic and FTA are discussed in [41] in order to cope with the information uncertainty due to limited data of the failure components probability, whereas [42] presents an improved methodology for analysing the qualitative importance of components in the functional and reliability structures of a system.…”

Archives of Foundry Engineering

“…However, the most important problem when saturating the preform with liquid metal is the atmospheric air present in the reinforcement capillaries. During the saturation, the capillaries' air pressure increases proportionally to the pressure acting on the metal, making it impossible to fill the moulded part completely, which results in the formation of porosity defects and lowering the quality of the material [2,7,[11][12][13][14][15][16][17][18][19]. Therefore, the fundamental phenomenon to be analysed is the pressure changes in the composite casting during the solidification of its metal matrix.…”

“…Methods are known to eliminate this problem, such as saturation in the autoclave, which consists in immersing the ceramic preform in the liquid metal, where a vacuum is created in the first stage of the process to remove air from the capillaries, and then the pressure in the chamber is equalized, causing the capillaries to be filled with liquid alloy [2,6,8,11,[15][16][17][18][19][20][21][22][23][24]. These methods, although effective, do not fit in with foundry technologies, where, by definition, the shape of the casting is given by the mould.…”

The Comparing of the Selected Temperature Sensors Compatible with the Arduino Platform

“…Two scales were standardized to measure the temperature: the Kelvin and the Celsius temperature scale [2]. The current level of progress is influenced by advanced information technologies [3]. In automation technique, the temperature belongs to the most monitored quantities in production and also non-production processes and the quality and production cost of many products and services often depend on its accuracy [4].…”