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Software Engineering PS (WS2000/2001)

© Copyright 2000, Schwaiger Roland










Elaboration Phase

Referenzen: 10

The purpose of the elaboration phase is to analyze the problem domain, establish a sound architectural foundation, develop the project plan and eliminate the highest risk elements of the project. Architectural decisions have to be made with an understanding of the whole system: its scope, major functionality and nonfunctional requirements s.a. performance requirements.

In the elaboration phase, an executable architecture prototype is built in one or more iterations, depending on the scope, size, risk and novelty of the project. This effort should at least address the critical use cases identified in the inception phase, which typically expose the major techical risks of the project. While an evolutionary prototype of a production-quality component is always the goal, this does not exclude the development of one or more exploratory, throw-away prototypes to mitigate specific risks s.a. design/requirements trade-offs, component feasibility study, or demonstrations to investors, and end-users.

The outcome of the elaboration phase is:

  • A use-case model (at least 80% complete) - all use cases and actors have been identified, and most use-case descriptions have been developed.
  • Supplementary requirements capturing the non functional requirements and any requirements that are not associated with a specific use case.
  • A Software Archtitecture Description.
  • An executable architectural prototype.
  • A revised risk list and a revised business case.
  • A development plan for the overall project, including the coarse-grained project plan, showing iterations and evaluation criteria for each iteration.
  • An updated development case specifying the process to be used.
  • A preliminary user manual (optional).

At the end of the elaboration phase is the second important project milestone, the Lifecycle Architecture Milestone. At this point, you examine the detailed system objectives and scope, the choice of architecture, and the resolution of the major risks. The main evaluation criteria for the elaboration phase involves the answers to these questions.

  • Is the vision of the product stable?
  • Is the architecture stable?
  • Does the executable demonstration show that the major risk elements have been addressed and credibly resolved?
  • Is the plan for the construction phase sufficiently detailed and accurate? Is it backed up with a credible basis of estimates?
  • Do all stakeholders agree that the current vision can be achieved if the current plan is executed to develop the complete system, in the context of the current architecture?
  • Is the actual resource expenditure versus planned expenditure acceptable?
The project may be aborted or considerably re-thought if it fails to pass this milestone.

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