User interface design: the WHO, the WHAT, and the HOW revisited

As soon as user interface design is seen as an integral part of business- and user-oriented software development, a framework and a methodology are required for development support. The hereby introduced TADEUS-approach provides both, and is currently being implemented, in order to provide developers with a corresponding environment. The approach is dedicated to the integration of the specification of interacting users (WHO) allowing individual perspectives, as well as the specification of a system´s functionality in a declarative (WHAT) and procedural way (HOW). The design methodology is model-driven and object-oriented. It supports the specification and integration of business models, user models, interaction models, and data models. Any specification may be reused for prototyping and further application development