Usually the goals objectives and constraints are

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Unformatted text preview: en more attractive than those that were not selected. Consequently, it is reasonable to expect the system to be defined with increasingly better resolution as time passes. This tendency is formalized at some point (in Phase B) by defining a baseline system definition. Usually, the goals, objectives, and constraints are baselined as the requirements portion of the baseline. The entire baseline is then subjected to configuration control in an attempt to ensure that successive changes are indeed improvements. As the system is realized, its particulars become clearer—but also harder to change. As stated above, the purpose of systems engineering is to make sure that the development process happens in a way that leads to the most cost-effective final system. The basic idea is that before those decisions that are hard to undo are made, the alternatives should be carefully assessed. The systems engineering process is applied again and again as the system is developed. As the system is realized, the issues addressed evolve and the particulars of the activity change. Most of the major system decisions (goals, architecture, acceptable life-cycle cost, etc.) are made during the early phases of the project, so the turns of the spiral (that is, the successive refinements) do not correspond precisely to the phases of the system life cycle. Much of the system architecture can be ''seen" even at the outset, so the turns of the spiral do not correspond exactly to development of the architectural hierarchy, either. Rather, they correspond to the successively greater resolution by which the system is defined. Each of the steps in the systems engineering process is discussed below. NASA Systems Engineering Handbook Fundamentals of Systems Engineering Recognize Need/Opportunity. This step is shown in Figure 3 only once, as it is not really part of the spiral but its first cause. It could be argued that recognition of the need or opportunity for a new system is an entrepreneurial activ ity, rather than an engineering one. The end r...
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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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