Requirements Specification - 3
Semi-formal/Graphical notations
- Graphical notations have a loose semantics associated with the structure
- Widely used, e.g. SADT [Ross,1977], SSA [DeMarco,1978] [Gane/Sarsen,1979] [Yourdon/Constantine,1979]
Formal/Mathematical notations
- Formal specifications base on a formal semantics (mathematical concept)
- Specifications are unambiguous (reduce the arguments between customer and contractor about system functionality)
- Difficult to understand for customer
- Examples: Finite State Machines, Petri Nets [Peterson,1977], Algebraic Specifications, Z [Hayes,1987], VDM [Jones,1980]