Influence diagram approach

History and Technical Basis. The influence diagram approach (IDA) (also known as the sociotechnical approach to human reliability (STAHR) (see Phillips et al., 1990) is a technique that is used to evaluate human error probabilities as a... 

Phillips, L. D., Embrey, D. E., Humphreys, P., Selby, D. L. (1990). A Sociotechnical Approach to Assessing Human Reliability. In R. M. Oliver J. A. Smith (Eds.), Influence Diagrams, Belief Nets and Decision Making Their Influence on Safety and Reliability. New York Wiley. 

In order to produce methodologies that incorporate physical aspects of the system in the analysis, additive weighting systems have been constructed, like UPM (Brand and Gabbot 1993), and Influence Diagram models have been developed to represent dependencies in a more flexible manner (Zitrou and Bedford 2007). In addition, these modelling approaches represent expert judgment in a quantitative maimer and can be used in cases where limited or even no data exists. 

Several authors have suggested ways (checklists, influence diagrams) for determining beta values (Humphreys, 1987, Brand, 1996, Johnston, 1987, Zitrou and Bedford, 2003, Zitrou et al., 2003, lEC 61508, 2010, lEC 62061, 2005). An overview of these approaches is provided in Rausand and Hokstad (2008). The first approaches, such as Humphreys (1987) and Brand (1996) were developed with basis in the Nuclear industry, and build on insight and experience from this sector. Zitrou and Bedford (2003) and Zitrou et al. (2003) have extended the approach by Brand (1996) to include site-specific factors into influence diagrams. Insight to these methods has to some extent been used as inspiration for the checklists proposed in Section 6. 

This approach is based on six function testing and inspection tasks (i) scheduling (ii) preparation, execution, and restoration (iii) failure reporting (iv) failure analysis (v) implementation and (vi) validation and continuous improvements. Thus, the approach is composed of six tasks based on checklists and analytical methods, such as influence diagrams, cause-defense matrices, and operational sequence diagrams (OSD). The six tasks are described as follows [11] ... 

FIG. 2.4. Mental models approach Influence diagram for risk produced by radon. Source Bostrom, Fischhoff, and Morgan (1992). (In Morgan, Fischhoff, Bostrom,. Atman, 2001, p. 49). Reprinted with the permission of Cambridge University Press. 

Tay] Taylor, J.A., Schaffer, G.B., St. John, D.H., The Role of Iron in the Formation of Porosity in Al-Si-Cu-Based Casting Alloys Part II. A Phase-Diagram Approach , Metall. Mater Trans. A, 30A, 1651-1655 (1999) (Calculation, Crys. Structure, Experimental, 12) [2000Bha] Bhattamishra, A.K., Chattoraj, L, Basu, D.K., De, P.K., Study on the Influence of the Si/Fe Ratio on the Corrosion Behavior of Some Al-Fe-Si Alloys , Z Metallkd., 91(5), 393-396... 

The density functional approach has also been used to study capillary condensation in slit-like pores [148,149]. As in the previous section, a simple model of the Lennard-Jones associating fluid with a single associative site is considered. All the parameters of the interparticle potentials are chosen the same as in the previous section. Our attention has been focused on the influence of association on capillary condensation and the evaluation of the phase diagram [42]. 

Key documents for the technical definition of the process are the flow diagram, the cause-and-effect diagram, and the influence matrix. The details of the cause-and-effect diagram and the influence matrix will be discussed under experimental approach in a later section. 

The approach has similarities with a bow-tie model One starts broad and collects all available process information. A structure is used, e.g., a tree diagram, to create a format for the information needed and collected. One should concentrate on the essentials and collect all relevant factors that influence the process, from the outside to the inside. Setting the boundaries of the process early reduces rework later on however, this clearly limits the degree of design novelty that can be achieved. 

The problem is, therefore, to influence the damping in these two frequency ranges independently of each other. Because time and temperature have analogous effects, we consider the diagram of tan 8 as a function of T for a vulcanized rubber (Figure 7.14). The frequencies for friction are so high that we already approach the peak at... 

Schematic potential energy diagrams for two particles are depicted in Figure 4.34. As two particles approach, the presence of the adsorbed polymer molecules around the particles leads to a steric interaction in which the thickness of the adsorbed layer is greater than half the surface separation distance. Therefore, the particles do not get close to the primary minimum. The steric interaction Vs is influenced by two parameters ...

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