Incidents behaviour models

Step 4. Every element in such a tree will be classified according to the chosen human behaviour model, or at least every "root cause" (the end points of the tree) will be. In this way the fact that any incident usually has multiple causes is fully recognised. Each near miss report is analysed to produce a set of classifications of causal elements instead of the... 

When the EPA considered exposures to insecticide residues in the home they identified at least six possible sources and routes these are given in Table 2.6. Their original approach apportioned the acceptable daily intake (ADI) between the various routes but it soon became clear that this was unrealistic because an individual was unlikely to be exposed via all routes on any one day. The EPA s present strategy is to develop an approach called micro-exposure event modelling. Micro-exposure event modelling is based on statistical data on the frequencies and levels of contamination of food, water, etc. and on behavioural information about the frequency of use of lawn/pet/timber treatments, etc. The combined data are assembled in a probabilistic model called LIFELINE which is able to predict the frequency and level of exposure to a group of hypothetical individuals over their lifetime.12 The model is also able to take account of the relative proportions of different types of accommodation, the incidence of pet ownership or any other data that will affect real levels of exposure. The output from the LIFELINE model allows the exposures of individuals in a population to be modelled over any interval from a single occasion to a lifetime. 

I, Chapters 2 and 3 deal with the general backgrounds of industrial safety (e,g, models of accident causation and of human behaviour) and with the contributions that near miss reporting could make in understanding and controlling accidents and incidents, Also theoretical criticisms of the near miss reporting efforts are discussed here,... 

In this chapter a simple model of incident causation is presented and the relative importance of three groups of factors contributing to industrial safety will be discussed Technical, Organisational and Behavioural Factors. Historic trends or fashions focussing on one of these thpee factors will be described, followed by recent results of the situation in the chemical process industry in the Netherlands. 

In the previous chapters the purposes of near miss reporting have been outlined and a framework of designing such a safety management tool has been presented. The importance of human behaviour as a dominant factor in incident sequences was stressed by developing a system failure classification scheme largely based on a theoretical model of operator behaviour. Also an overview was given of the organisational factors necessary for a successful implementation of a NMMS. 

As an alternative, the current paper presents an approach for analysis of aviation incidents that takes a multi-agent perspective, and is based on formal methods. The approach is an extension of the approach introduced in the work of Bosse and Mogles [4], which was in turn inspired by Blom, Bakker, Blanker, Daams, Everdij and Klompstra [1]. Whereas this approach mainly focuses on the analysis of existing accidents (also called accident analysis or retrospective analysis), the current paper also addresses analysis of potential future accidents (called risk analysis or prospective analysis). This is done by means of a multi-agent simulation framework that addresses both the behaviour of individual agents (operators, pilots) as well as their mutual communication, and interaction with technical systems. By manipulating various parameters in the model, different scenarios can be explored. Moreover, by means of automated checks of dynamic properties, these scenarios can be assessed with respect to their likelihood of the occurrence of accidents. The approach is illustrated by a case study on a runway incursion incident at a large European airport in 1995. 

The various incident and accident scenarios to be considered in a PSA for aNPP are generally characterized by complex interactions over time between the physical process, the behaviour of technical systems, hiunan actions, and stochastic influences. However, the main models to be applied are static event-tree and fault-tree models built on the basis of information from a set of separately performed simulations. 

The time-to-loss-of-strength is strongly sensitive to the accuracy of the radiative component of the total incident heat flux. This kind of the model behaviour was also very recently independently reported in Ref. 7. 

It is therefore possible, once the causes of the incident have been defined, to provide guidance to the investigator to help determine whether a behaviour represented an error or a violation, and whether there may be issues relating to the safety culture of the organisation. A preferred safety culture model can be mapped onto the RCA model. 

For this paper we treat hazard assessment as a combination of two interrelated concepts hazard identification, in which the possible hazardous events at the system boundary are discovered, and hazard analysis, in which the likelihood, consequences and severity of the events are determined. The hazard identification process is based on a model of the way in which parts of a system may deviate fi om their intended behaviour. Examples of such analysis include Hazard and Operability Studies (HAZOP, Kletz 1992), Fault Propagation and Transformation Calculus (Wallace 2005), Function Failure Analysis (SAE 1996) and Failure Modes and Effects Analysis (Villemeur 1992). Some analysis approaches start with possible deviations and determine likely undesired outcomes (so-called inductive approaches) while others start with a particular unwanted event and try to determine possible causes (so-called deductive approaches). The overall goal may be safety analysis, to assess the safety of a proposed system (a design, a model or an actual product) or accident analysis, to determine the likely causes of an incident that has occurred. 

The behaviour of the explosion and effects cannot be predicted with the more commonly used models such as the multi-energy model. More sophisticated models may be able to estimate the explosion hazards and risks for particular sites. Otherwise it is proposed that consequence assessments are based on the experience of the Buncefield incident. 

Figure 2.8.1 3 Domino incident model related to behavioural activity...

The example provided in Figure 2.8.14 relates to the condition of stress and demonstrates how the model can be applied to chronic health and safety issues. It shows how stress incidents can be analysed in such a way to influence the behaviours of managers, supervisors and operators. 

Figure 2.8.14 Behavioural incident model applied to a stress incident...

Many models for accident causation have been used to propose ideas to minimize loss. The systems approach was developed to manage safety. This approach promotes a balance between the assessment of people, behaviour and the infrastructure to support the operation. However, given the adoption of safety systems in many organizatiorrs, there are questions surrotmding organizational incidents that remain tmanswered by many of these systems. 

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