Positive tree

Sue = selectively protected sucrose with the primary position tree either at C-1 orC-6 or C-6 ... 

Heumann, K., Mewes, H.-W. (1996) The Hashed Position Tree (HPT) a sufGx tree variant for large data sets stored on slow mass storage devices. In Proceedings of the 3rd South American Workshop on String Processing, Carleton University Press, Ottawa 101-114. 

There are two basic types of analytical tree. The positive tree, or objective tree, which is developed to ensure that a system works properly, and the negative tree, or fault tree, which is generally used for troubleshooting and to investigate system failures (Fig. 10-2). 

These same positive trees are very useful feeder documents for many types of hazard analysis. For example, the item layout for failure mode and effects analysis worksheets can be taken directly from the positive tree for the project. Positive trees can easily be converted into negative trees for troubleshooting or accident analysis. 

The management oversight and risk tree (MORT) chart is a large, complex, negative tree (see Chapter 18). Even though the project evaluation tree (PET) is depicted as a positive tree, it is mentally converted and used as a fault tree for accident analysis applications (see Chapter 16). 

To construct an analytical tree, the first thing to be done is to define the top event. For an objective or positive tree, define what you want to design, build. 

Construct an analytical tree. The tree can be on any subject and either a positive tree or a negative tree. Include at least four tiers in its longest branch, not including the top event as a tier. 

FlgRre 15-7 Positive tree with success probability calculated using reliability data. 

The program developed was the Combat-Oriented Mishap Prevention Analysis System (COMPAS). It used two analytical charts. One, the COMPAS A chart, was basically a big positive tree showing the overall organization of a typical TAC wing, broken down organizationally and then broken down into the people, procedures, and facilities and hardware for that particular part of the organization. 

This technique reverses the logic of fault tree analysis. In positive tree design, a system for successful operation is comprehensively and logically laid out. The positive tree is an excellent planning and assessment tool because it shows all that must be performed and the proper sequencing of events needed to accomplish an objective. 

A second set of procedures that has been developed to analyze safety problems involves the use of analytical trees. Analytical tree-methods are deductive methods asking either "how could this have happened " (fault trees), or "how could we make this happen" (positive trees). Analytical trees derive their name from the logic diagram generated by the method which resembles a multi-branched tree. 

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