double role deeply contributes to most of the problems encountered in information systems design.
Each application development is most of the time independant from all others. But, when examining the applications that have been developed for W e r e n t organisations of the same domain, we straight on notice similarities. As a matter of fact, each application domain, e.g. banks, insurance or medicine, contains a certain unity in aim, the typology of actors, in and out flows, and sometimes even in the internal organization. Intuitively, one can note that there are "classical examples of applications" from which one-off software could be derived.
These observations introduced us to think of a new way of software development. We would like to offer each applicationdomain a way to share the common elements without proposing a ready-to-use solution. Our idea consists in pooling the similarities in a generic system and to provide users with tools to build their personnal application from this system. We also have mowed roles of actors to provide each with tasks more adapted to hisher knowledge. We thus have defined three types of actors : the computer scientist, the user-designer, and the end user. The computer scientist designs the generic model ; the resulting canvas is adapted by the user- designer to the specificities of his service ; the end user uses the specific application like any other one. A synthetic representation of our approach is given on figure 1 :