Evolutionary Software Development: an Experience Report on Technical and Strategic Requirements Biographical: Andreas Zamperoni Received a Master Degree in Computer Science from the Technical Uni

Traditional software engineering approaches are no longer suitable when dealing with the development of innovative, complex software systems, such as e.g. applications of neural networks for geophysical subsurface modeling. At TNO, we succeeded to deene and to establish a \hybrid" life cycle plan that integrates the developers' view of a creative, exible and unrestricted development process on the basis of evolutionary prototyping with the management's needs for organization, controllability, and clearness of a software project. We report the experiences we made when applying the evolutionary life cycle plan to multilateral software projects, and compare them with systems developed following the traditional approach. In this paper, we focus on the most crucial technical and strategic requirements for (controlled) evolutionary software development. We discuss the issues of team structure, commitment of, and communication with users, frequent testing, integration & version control, component reusability, and management capabilities that become important considerations when replacing a traditional sequential by an evolutionary life cycle plan. where he investigates, evaluates, and enhances software development of geo-scientiic software systems. Bart Gerritsen received a master degree in mechanical engineering specializing in CAD from the Delft Technical University (The Netherlands). He has been, among other, a senior system developer and project leader at Cap Gemini. Since 1991, he is project leader and software quality assurance oocer at TNO Institute of Applied Geoscience (Delft, The Netherlands). He has also been a project leader of the TNO participation at a 20+ man year international project funded by the EC. Bert Bril received a master degree in geophysics from the Delft Technical University (The Netherlands). He has worked as eld geophysicist, and been a senior system developer and at Cap Gemini and Jason Geosystems. Since 1992, he is senior system designer and technical project leader at TNO Institute of Applied Geoscience (Delft, The Netherlands).