Tree construction

Both types of trees have several uses. 

Analytical trees display clear thinking. By graphically putting a project on paper, the project engineer ensures that he or she has looked at all the alternatives and understands project requirements. 

Analytical trees force individuals to use the deductive analysis process and to think about the events that must occur at lower levels for output events to be generated. 

Analytical trees show how relationships and interfaces occur during a project. 

Root causes are sought and identified when analytical trees are used for accident analysis. 

---

Fault Tree Construction. Eault tree constmction begins at the TOP event and proceeds, level by level, until all fault events have been developed to their basic contributing causes (BASIC events). The analyst begins with the TOP event and, for the next level, determines the immediate. 

Before the analyst begins fault tree construction, it is necessary to document and understand System design,... 

The success of some systems depends on other systems. An event tree is constructed by placing support systems before the supported systems. This may require iterating the event tree construction to get appropriate ordering. If the system dependency is in the fault trees, it is not reflected in the event tree and only becomes apparent when the PSA is calculated. 

Event tree construction and analysis (graphic and text) ... 

It is illustrated in Section 3.4.4 by tracing the paths for leaking engine compression and applied to fault tree construction for the FFTF reactor Fullwood and Erdmann, 1974). The method involves writing Boolean equations for all paths whereby hazardous material may be released. It is primarily useful for enumerating release paths, but not for what started the release It was used to enumerate the possible paths for stealing nuclear bomb material from a facility. 

A dependency analysis determines which systems depend on other systems. This may require iterating the event tree construction to put a support system before the systems affected. 

Fullwood, R. and R. C. Erdman, 1974, On the Use of Leak Path Analysis in Fault Tree Construction for Fast Reactor Safety, CONF-74040I-P3. 

Fussell, J. B. 1975, Computer Aided Fault Tree Construction for Electrical System and Fault Tree Analysis, SIAM, Philadelphia, PA, p 37. 

The fault tree is a graphic representation of the relationships between basic events and the selected top event. Table 4.24 presents the standard symbols used in fault tree construction to show these relationships. 

Other considerations for fault tree construction are (/) assume that faults propagate through normally operating equipment. Never assume that a fault is stopped by the miraculous failure of another piece of equipment. (2) Gates are connected through labeled fault events. The output from one gate is never connected directly into another. 

A) A distance matrix was constructed from the inferred amino acid sequences using a Poisson correction for multiple hits and the tree constructed using the minimum evolution approach. Five hundred bootstrap resamplings were carried out. Branches with bootstrap support values less than 50% are indicated with an asterisk. 

Phylogenetic tree construction is based on cladistics, the systematic classification of groups of organisms on the basis of shared characteristics thought to derive from a common ancestor. The basic assumptions of cladistics are ... 

In dynamic SDR, the positions of members are not pre-assigned. Instead, the spaces in the key tree are dynamically allocated and reclaimed, adapting to the current set of active members. More specifically, the GCKS dynamically creates leaves when new member joins, or discards a subtree when all positions of the subtree are inactive. By doing this, the GCKS maintains active members in a dynamic key tree, rather than a large key tree constructed in advance. 

---