Introduction to Design Patterns
Within each engineering discipline, engineers have found that when analysing problems, similar types of sub-problems would tend to recur from time to time. Having had experience from previous project work, they knew that a similar solutions to those problems could be reused. This became the basis for design patterns.
Introduction to the Unified Process
The traditional view of system implementation is seen as a series of steps toward implementation, covering areas such as analysis, design, construction, documentation, handover, etc. Hay (1997) gives a good undertaking of the traditional approach stating: