Uncertainty handling in fault tree based risk assessment: State of the art and future perspectives

Abstract

Risk assessment methods have been widely used in various industries, and they play a significant role in improving the safety performance of systems. However, the outcomes of risk assessment approaches are subject to uncertainty and ambiguity due to the complexity and variability of system behaviour, scarcity of quantitative data about different system parameters, and human involvement in the analysis, operation, and decision-making processes. The implications for improving system safety are slowly being recognised; however, research on uncertainty handling during both qualitative and quantitative risk assessment procedures is a growing field. This paper presents a review of the state of the art in this field, focusing on uncertainty handling in fault tree analysis (FTA) based risk assessment. Theoretical contributions, aleatory uncertainty, epistemic uncertainty, and integration of both epistemic and aleatory uncertainty handling in the scientific and technical literature are carefully reviewed. The emphasis is on highlighting how assessors can handle uncertainty based on the available evidence as an input to FTA.

Risk Assessment of Oxygen Lance Burning Loss Using Bow-Tie Analysis Based on Fuzzy Theory

“…e fuzzy theory proposed by Khakzad et al [16] addresses such problems and is often employed to solve the problem of uncertainty. In recent study, Yazdi et al discussed the development and improvement of fuzzy theory [17]. Tanaka [18] was the first researcher to apply the fuzzy theory in the FTA.…”

Ignorance‐aware safety and reliability analysis: A heuristic approach

“…It is important to consider that in a general group decision‐making problem, each employed expert always expects that his or her opinions should be accepted by the rest of the group members. In other words, the final evaluation outputs should be close to his or her opinions . It means that if the final evaluation result is close to his or her opinions, subsequently, the experts are willing to accept the final opinions.…”

“…In other words, the final evaluation outputs should be close to his or her opinions. 78,79 It means that if the final evaluation result is close to his or her opinions, subsequently, the experts are willing to accept the final opinions. Otherwise, he or she might refuse it.…”

A novel method for occupational safety risk analysis of high-altitude fall accident in architecture construction engineering

“…Among the different probabilistic risk assessment (PRA) methods, FTA is the most-widely used approach for system safety and reliability evaluation. Fault tree analysis (FTA) is a quantitative risk analysis method and can be applied to major unwanted events (Yazdi, Kabir, and Walkerb 2019). FTA method is an effective tool for the occupational safety analysis of complex system, it looks the fault status that we mostly do not want to happen as the goal of fault analysis system, then look for factors that lead to the occurrence of the fault, and looks for these next-level factors, until the original factors that we do not want to further process.…”

“…Therefore, it is necessary to quantify the failure probability of each basic event to be able to measure the probability of the top event. The criticality of the basic events can also be determined by calculating their relative contributions to the occurrence of the top event (Yazdi, Kabir, and Walkerb 2019). In the DFTA (dynamic fault tree analysis) method, some dynamic logic gates (such as sequence enforcer gates, functional dependency gates, priority and gates, cold spare gates, warm spare gates and so on) are added, which can help to analyze the dynamic and sequential functions of the system.…”