Human Reliability Analysis Models

Podofillini, L. Dang, V.N. 2013. A Bayesian Approach to Treat Expert-Elicited Probabilities in Human Reliability Analysis Model Construction. Reliability Engineering System Safety, 117 52-64. 

Human error probabilities can also be estimated using methodologies and techniques originally developed in the nuclear industry. A number of different models are available (Swain, Comparative Evaluation of Methods for Human Reliability Analysis, GRS Project RS 688, 1988). This estimation process should be done with great care, as many factors can affect the reliability of the estimates. Methodologies using expert opinion to obtain failure rate and probability estimates have also been used where there is sparse or inappropriate data. 

Such a task description invites task analysis, which would lead naturally to human reliability analysis (HRA). Indeed, perhaps the earliest work in this field applied HRA techniques to construct fault trees for aircraft structural inspection (Lock and Strutt 1985). The HRA tradition lists task steps, such as expanded versions of the generic functions above, lists possible errors for each step, then compiles performance shaping factors for each error. Such an approach was tried early in the FAA s human factors initiative (Drury et al. 1990) but was ultimately seen as difficult to use because of the sheer number of possible errors and PSFs. It is occasionally revised, such as in the current FRANCIE project (Haney 1999), using a much expanded framework that incorporates inspection as one of a number of possible maintenance tasks. Other attempts have been made to apply some of the richer human error models (e.g.. Reason 1990 Hollnagel 1997 Rouse 1985) to inspection activities (La-toreUa and Drury 1992 Prabhu and Drury 1992 Latorella and Prabhu 2000) to inspection tasks. These have given a broader understanding of the possible errors but have not helped better define the PoD curve needed to ensure continuing airworthiness of the civil air fleet. 

Under the AMM cluster a thematic network (FP-4 project IS ANEW) was set up in order to develop and compare different methods in order to study the interaction between human and technological systems. Attention was focused on methodologies based upon the integrated sequence analysis (ISA) of possible events, considering both the human system and the physical process. Sequences of events are simulated through modeling of the plant system and the actions of the operators. Input data used for the simulation come from different disciplines such as probabilistic safety assessments (PSA) and human reliability analysis studies. The... 

A Bayesian network model for dependence assessment in human reliability analysis... 

A review of decision tree models for assessing Human Reliability Analysis dependence... 

ABSTRACT In Human Reliability Analysis (HRA) the assessment of dependence between human failure events refers to evaluating the influence of the failure on one task on the performance of the subsequent task. In Probabilistic Safety Assessments (PSAs), human action dependencies are commonly evaluated with the THERP method, often extended with Decision Tree (DT) models, to reduce the expert judgment element. This paper compares different DT models used in the HRA practice. The comparison addresses the factors entering the models and the underlying relationships. The comparison shows that, depending on the features of the task under analysis, the results may vary substantially if different DTs are used. Also, often there is limited guidance for the analyst in the assessment of the DT factors this prejudices the repeatability of the assessments because different analysts may very well decide for different assessments. 

Human Reliability Analysis (HRA) is the part of Probabilistic Safety Assessment (PSA) that deals with human performance and its impact on risk. The main activities in an HRA are the identification of the human failure events (HFEs) to model, their analysis, and the quantification of their probability. 

Konstandinidou, M., Nivolianitou, Z., Kyranoudis C. Markatos, N., 2006. A fuzzy modelling application of CREAM methodology for human reliability analysis. Reliability Engineering System Safety 91(6) 706—716. 

Mosleh, A., Chang, Y. H. (2004). Model-based human reliability analysis prospects and requirements. Reliability Engineering and System Safety, 81, 241-253. 

On international level, in addition special aspects like the development of appropriate quantification algorithms in the fire PRA model in order to accurately calculate component importance measures are discussed by Kin and Han (2009). Moreover, in the U. S. a program has heen started to develop a methodology and associated guidance for performing quantitative human reliability analysis for post-fire mitigative human actions modeled in a Fire PSA. 

Failures of human actions are embedded either as basic events in the fault-tree or as function events in the event-tree models of a PSA. Corresponding probabilistic assessments are obtained from the application of HRA (Human Reliability Analysis)-trees. 

All of these techniques rely on past experience to a certain extent. Fault and event trees are the most common frequency modeling techniques for complex situations that require tracking of chains of events. Human reliability analysis and external events analysis can be considered essentially as components of fault and event tree analysis, with the information generated from their application to he fed into the fault and event trees. 

SPAR-H Standardized plant analysis risk human reliability analysis It is useful for the cases where detailed assessments are not called for, as it does not identify or model HFEs. It is possible to quantify HEPs for pre-initiator and post-initiator HFEs. It was initially used for nuclear application, but now has wider applications [12]. 

Models and data requirements for human reliability analysis 1989... 

Mosleh, A., Shen, S.H., Kelly, D.L., Oxstrand, J. Groth, K.M. 2012. A Model-Based Human Reliability Analysis Methodology. Proceedings of the International Conference on Probabilistic Safety Assessment and Management (PS AM 11), Helsinki, Finland. 

Podofillini, L., Dang, V.N., Zio, E., Baraldi, P. Librizzi, M. 2010. Using Models To Incorporate Expert Knowledge In Human Reliability Analysis—A Dependence Assessment Method. Risk Analysis 30(8) 1277-1297. 

The increasing use of Probabilistic Safety Assessment (PSA) to support regulatory and operational decisions requires that methods be developed to the extent possible on an empirically sound basis. For Human Reliability Analysis (HRA), this means that methods should be based on data from operational experience, studies in simulator environments, as well as theoretical cognitive models. A significant step in this direction has been achieved with the International and US HRA Empirical Studies, which aimed at an empirically-based understanding of the strengths and weaknesses of a number of HRA methods (Forester et al. 2013). 

This model has proved to be a useful tool, both in structuring human factors training and in analyzing the requirements of legislation and the current status of organizations (Konstantinos et al., 2011). The model is used in this research to structure the analysis of the factors considered in Human Reliability Analysis tools. 

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