Rolling wave planning vs progressive elaboration

"Software Defects" Please respond to the following:
Measuring and analyzing software defects is critical for software and system development. Describe the relationship between defect detection and rolling-wave adjustments. Determine the measures that may be performed to minimize the activities associated with rolling-wave planning.
Examine the factors that determine the availability of a system. Compare these factors and describe how they are interrelated. Suggest the tests that may be performed to determine these factors.

Classmate:

Measuring and analysing software defects is critical for software and system development. Describe the relationship between defect detection and rolling-wave adjustments. Determine the measures that may be performed to minimize the activities associated with rolling-wave planning.
Rolling Wave Planning is a technique that enables you to plan for a project as it unfolds. This technique, then, requires you to plan iteratively. The planning technique is very similar to those used in SCRUM or other Agile Methodologies. Essentially, when you use Rolling Wave Planning, plan until you have visibility, implement, and then re-plan.

For example, suppose you expect to complete the project in eight months, but only have clarity for the first three months: You would plan only for those three months. As the project progresses and you gain more clarity, you would then plan for the remaining months. The Rolling Wave Planning technique uses progressive elaboration, which is the act of elaborating the work packages in greater detail as the project unfolds.
Rolling Wave Planning is used when you just don’t have enough clarity to plan in detail the entire project. This lack of clarity could come from various factors, such as emerging requirements. Rolling Wave Planning is particularly useful in projects with high uncertainty.

http://www.brighthubpm.com/project-planning/48953-basics-of-rolling-wave-planning/

Examine the factors that determine the availability of a system. Compare these factors and describe how they are interrelated. Suggest the tests that may be performed to determine these factors.

Some factors that affect system availability include:
Management policies
Staff and driver morale
Correct matching of technician skills with their responsibilities
Correct data entry and system setup
Shop organization
Organized and easily accessible service manuals
http://www.government-fleet.com/channel/maintenance/article/story/2013/07/10-factors-affecting-fleet-availability-benchmarks.aspx