E critical path activities and how much spare time ie

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Unformatted text preview: e very useful. Two general types of graphical formats, shown in Figure 12, are used. One has activities-on-arrows, with products and dependencies at the beginning and end of the arrow. This is the typical format of the Program Evaluation and Review Technique (PERT) chart. The second, called precedence diagrams, has boxes that represent activities; dependencies are then shown by arrows. Due to its simpler visual format and reduced requirements on computer resources, the precedence diagram has become more common in recent years. The precedence diagram format allows for simple depiction of the following logical relationships: Role of Scheduling • Scheduling is an essential component of planning and managing the activities of a project. The process of creating a network schedule can lead to a much better understanding of what needs to be done, how long it will take, and how each element of the project WBS might affect other elements. A complete network schedule can be used to calculate how long it will take to complete a project, which activities determine that duration (i.e., critical path activities), and how much spare time (i.e., float) exists for all the other activities of the project. (See sidebar on critical path and float calculation). An understanding of the project's schedule is a prerequisite for accurate project budgeting. • • Activity B begins when Activity A begins (StartStart, or SS) Activity B begins only after Activity A ends (Finish-Start, or FS) Activity B ends when Activity A ends (Finish-Finish, or FF). NASA Systems Engineering Handbook Management Issues in Systems Engineering Each of these three activity relationships may be modified by attaching a lag (+ or-) to the relationship, as shown in Figure 12. It is possible to summarize a number of low-level activities in a precedence diagram with a single activity. This is commonly referred to as hammocking. One takes the initial low-level activity, and attaches a summary activity to it using the first relationship described above. The summary activity is then attached to the final low-le...
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This document was uploaded on 02/26/2014 for the course E 515 at University of Louisiana at Lafayette.

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