Documenting the Progress of the System Development

While UML gives an intuitive image of the system, formal methods provide the proof of its correctness. We can benefit from both aspects by combining UML and formal methods. Even for the combined method we need consistent and compact description of the changes made during the system development. In the development process certain design patterns can be applied. In this paper we introduce progress diagrams to document the design decisions and detailing of the system in successive refinement steps. A case study illustrates the use of the progress diagrams.