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Enemies of software projects:

• unclear, unstable requirements
• inadequate customer communication
• inefficient team communication
• unecessary complexity
• ineffective team behavior

How People Solve Problems

Software engineering models

• Waterfall
• Spiral
• Controlled Iteration
• Incremental Controlled Iteration

The Waterfall Model

• Based on Construction Model
• Easy to understand
• Once a phase is complete, it is not revisited
• Staff can specialize
• 'Assembly line' approach

Waterfall Model

Problems with the Waterfall

• Software development is about problem solving
• Requirements aren't fully known before design
• design requirements evolve during coding, etc

The Spiral Model

• Four Sectors
• Pass through sectors for prototype
• Another pass to get first Iteration
• Repeat
• More realistic than waterfall
• Difficult and expensive in real world

Spiral Model

The Controlled Iteration Model

• Four Phases:
• Inception
• Elaboration
• Construction
• Transition

Controlled Interation

Design activities

• User level use cases
• Package diagrams
• Sequence diagrams
• Class diagrams
• Class implementation
• System build

UML Guide