Æliens

1

• perspectives of modeling
• requirements engineering -- Fusion
• methods for analysis and design -- a comparative study

2

• {\em object-oriented design} -- decomposition into objects
• object model -- objects suffer and require
• heuristics -- balance between nouns and verbs
• evaluation -- eliminating spurious classes
• class design -- class, responsibilities and collaborations

3

• types -- as an organizing principle
• contracts -- obligations and benefits
• subtyping -- the substitutability requirement
• partial types -- designed to have subtypes

4

• contracts -- formal specification
• verification -- as a design methodology
• runtime consistency -- invariance