Refining UML Models

Requirement model and design model are obtained though integrating use-case diagram,class diagram,sequence diagram and state machine in UML.Consistency checking for these models are proposed,and the refinement rules about these models are achieved.Therefore,consistency checking for these models can be performed at requirement analysis and design stages,code can be generated by refining design model steadily.Following this way,we can find inconsistency problem of the software system at earlier stage,and reduce the cost at debugging the software system after code generation.