SUBJECTS tree experiment

Like checklists, the comprehensiveness of the various predefined trees varies. Some are very detailed with numerous categories and subcategories, whereas others may not fully reach root causes. This is hardly surprising, as the predefined trees are essentially a graphical representation of numerous checklists, organized by subject matter, such as human error, equipment failure, or other topics. The more comprehensive techniques were developed from many years of incident experience and management system experience across the chemical and allied industries. 

The use of checklists to supplement another root cause analysis method can be a very powerful technique, for example, human factors checklist(s) may be used in conjunction with logic trees. The checklist may be used as a guide during development of a logic tree, or as a check after the tree has been developed. The checklist essentially acts as a memory jogger to direct the investigation team. This is especially helpful if the team lacks previous experience in the subject matter. 

Masters and Houston (1966) have reported statements from a number of subjects who purportedly "felt" the interior of the body during psychedelic experiments. One subject told about sensing his "interior landscape," describing the "trees, vines, streams, waterfalls, hills, and valleys" of the body. Another described the sensation of blood flowing... 

The construction of fault trees is by far not a trivial task, but requires a lot of expert knowledge and experience. The quantification of fault trees is for the time being extremely problematic, because the available databases for the determination of unreliability data of components and other probability data need significant further development. However, the existing databases and subjective estimated values may be used if two different plant designs are to be compared with each other, as the absolute values at the end of the calculation are not of interest but, instead, their relative comparison. 

Indeed, the work shows that Boyle was enthralled with many Helmontian experiments, particularly that of the willow tree, which was supposed to show that all vegetables mm into water. His alter-ego Cameades carried out similar experiments that confirmed Van Hehnont s observations. He also paid close attention to Van Helmont s account of a wondrous solvent, the Alkahest, which was supposed to dissolve all bodies into water. Although Cameades admitted that he had not made the Alkahest, his interest in the subject suggests that he was inclined to believe in it [34]. As pointed out above, the acceptance of the Helmontian view that there is a universal solvent that could transform everything into elementary water implied an automatic rejection of the tria prima. 

In general, a logic tree consists a classical statistical tool for dealing with this type of assessment problems, in which based of the overall knowledge available, the engineer sets up a number of alternative models and associates to each choice a weight factor representative of his subjective (based on judgment or experience) belief on the validity of the choice. In this manner ... 

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