Methods and Tools for the Development of Mission-Critical Software-Intensive Systems Size and complexity of Software increase dramatically in new systems. Moreover, it plays a more and more critical role in many application areas such as avionics, space, ground transportation, automotive, medical devices or nuclear plants. Like in many other engineering domains, size and complexity can be mastered by putting more effort in the early stages of the software development life-cycle. This is also the way to go to increase at the same time quality and productivity for a software intensive project. To achieve these goals, Ellidiss offers products, technologies and services that are focused on: An industry proven software design methodology (HOOD). A rigorous architectural design language for the software within its execution environment (AADL). A powerful model processing technology based on the use of the prolog language (LMP).