Constraint symbol

Sequence from the left. Many times analytical trees are not specifically concerned about sequencing, but a natural sequence or a sequence that must be followed should be indicated with a constraint symbol, and the events should be sequenced from the left to right. 

Another symbol is the oval, which is used as a constraint symbol. Ovals are the footnotes or caveats in the system. They can be used to modify or to show additional information and can be attached to either a general event, a base event, or an undeveloped terminal event. They can be used in conjunction with logic gates. They generally show a specific condition or constraint or modify the meaning of either the event symbol or the gate. 

Special situations can be addressed by attaching a constraint symbol to an and gate or or gate and spelling out any special condition or requirement in the constraint symbol. 

The drives branch indicates that some decisions have already been made about the drives. The and gate indicates that both a hard disk drive and a floppy disk drive are desired. The constraint symbol indicates that internal... 

The next step is carefully wording the undesired top event. This step is important because the wording of the top event determines, to a large extent, the scope of the effort. There are two basic approaches to limiting the scope and thereby focusing the effort. One approach is to state all of the conditions and restrictions in narrative form in the top block. The second approach is to use constraint symbols and/or undeveloped terminal events on the first tier. 

The symbols used on the MORT chart are basically those used for other analytical trees (Chapter 10) and fault tree analysis (Chapter 15). They include the rectangle as the general event symbol, the circle as the base event symbol, the diamond as an undeveloped terminal event, the and gate, the or gate, and the ellipse as a constraint symbol (Rgs. 18-1 and 18-2). 

Constraint symbol Gate constraint Event constraint... 

The primary symbols used for most analytical trees have been used in the MORT event tree as well. These include the rectangle (primary or top event, and secondary, contributory or main events), the diamond (undeveloped event), the circle (basic event), the and gate, the or gate, the oval (conditional or constraint symbol), and the triangle (transfer gate or symbol). In addition to these symbols, the MORT... 

Figure 26 Main results for the Rouse model with constraints. Symbols correspond to grid parameter j=1 with chain iengths /V=16,32,64,128, whereas p=2 results are shown by lines for N=32,64,128,256. The four panels show monomer mean-square displacement (a) and (c), end-to-end relaxation (b), and stress relaxation (d).

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